USEPA 2004 Guidelines for Water Reuse - (2023)

EPA/625/R-04/108 September 2004

Guidelines for Water Reuse

U.S. Environmental Protection Agency Municipal Support Division Office of Wastewater Management Office of Water Washington, DC

Technology Transfer and Support Division National Risk Management Research Laboratory Office of Research and Development Cincinnati, OH

U.S. Agency for International Development Washington, DC


This document was produced by Camp Dresser & McKee, Inc. under a Cooperative Research and Development Agreement with the US Environmental Protection Agency. It has been subjected to the Agency’s peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.



In an effort to help meet growing demands being placed on available water supplies, many communities throughout the U.S. and the world are turning to water reclamation and reuse. Water reclamation and reuse offer an effective means of conserving our limited high-quality freshwater supplies while helping to meet the ever growing demands for water. For many years, effluent discharges have been accepted as an important source for maintaining minimum stream flows. The investment in treatment technologies required to meet restrictive discharge limits has lead an increasing number of industries and communities to consider other uses for their treated wastewater effluents as a means to recover at least a part of this investment. Further, as sources of water supplies have become limited, there has been greater use and acceptance of reclaimed wastewater effluents as an alternative source of water for a wide variety of applications, including landscape and agricultural irrigation, toilet and urinal flushing, industrial processing, power plant cooling, wetland habitat creation, restoration and maintenance, and groundwater recharge. In some areas of the country, water reuse and dual water systems with purple pipe for distribution of reclaimed water have become fully integrated into local water supplies. The 2004 Guidelines for Water Reuse examines opportunities for substituting reclaimed water for potable water supplies where potable water quality is not required. It presents and summarizes recommended water reuse guidelines, along with supporting information, as guidance for the benefit of the water and wastewater utilities and regulatory agencies, particularly in the U.S. The document updates the 1992 Guidelines document by incorporating information on water reuse that has been developed since the 1992 document was issued. This revised edition also expands coverage of water reuse issues and practices in other countries. It includes many new and updated case studies, expanded coverage of indirect potable reuse and industrial reuse issues, new

information on treatment and disinfection technologies, emerging chemicals and pathogens of concern, economics, user rates and funding alternatives, public involvement and acceptance (both successes and failures), research activities and results, and sources of further information. It also includes as an updated matrix of state regulations and guidelines, and a list of state contacts. This information should be useful to states in developing water reuse standards, and revising or expanding existing regulations. It should also be useful to planners, consulting engineers and others actively involved in the evaluation, planning, design, operation or maintenance of water reclamation and reuse facilities. Benjamin H. Grumbles Assistant Administrator for Water U.S. EPA Paul Gilman Assistant Administrator for Research & Development U.S. EPA Jacqueline E. Schafer Deputy Assistant Administrator Bureau for Economic Growth, Agriculture and Trade U.S. Agency for International Development



Chapter 1



INTRODUCTION ........................................................................................................................................ 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Objectives of the Guidelines ............................................................................................ 1 Water Demands and Reuse .............................................................................................. 1 Source Substitution .......................................................................................................... 2 Pollution Abatement ......................................................................................................... 3 Treatment and Water Quality Considerations ................................................................... 3 Overview of the Guidelines .............................................................................................. 4 References ....................................................................................................................... 5


TYPES OF REUSE APPLICATIONS ......................................................................................................... 7 2.1 Urban Reuse .................................................................................................................... 7 2.1.1 Reclaimed Water Demand ................................................................................... 8 2.1.2 Reliability and Public Health Protection ............................................................... 9 2.1.3 Design Considerations ....................................................................................... 10 Water Reclamation Faciliities ............................................................... 10 Distribution System .............................................................................. 10 2.1.4. Using Reclaimed Water for Fire Protection ........................................................ 12 Industrial Reuse ............................................................................................................. 13 2.2.1 Cooling Water .................................................................................................... 13 Once-Through Cooling Water Systems ................................................. 13 Recirculating Evaporative Cooling Water Systems ............................... 13 Cooling Water Quality Requirements .................................................... 15 2.2.2 Boiler Make-up Water ........................................................................................ 16 2.2.3 Industrial Process Water ................................................................................... 17 Pulp and Paper Industry ....................................................................... 17 Chemical Industry ................................................................................ 17 Textile Industry .................................................................................... 17 Petroleum and Coal .............................................................................. 20 Agricultural Reuse .......................................................................................................... 20 2.3.1 Estimating Agricultural Irrigation Demands ........................................................ 21 Evapotranspiration ................................................................................ 21 Effective Precipitation, Percolation and Surface Water Runoff Losses ...................................................................................... 21 2.3.2 Reclaimed Water Quality ................................................................................... 22 Salinity ................................................................................................. 23 Sodium ................................................................................................. 23 Trace Elements .................................................................................... 24 Chlorine Residual .................................................................................. 24 Nutrients ............................................................................................... 24 2.3.3 Other System Considerations ........................................................................... 26 System Reliability ................................................................................ 26





Page Site Use Control ................................................................................... 26 Monitoring Requirements ...................................................................... 26 Runoff Controls .................................................................................... 26 Marketing Incentives ............................................................................ 27 Irrigation Equipment .............................................................................. 27 Environmental and Recreational Reuse .......................................................................... 27 2.4.1 Natural and Man-made Wetlands ....................................................................... 28 2.4.2 Recreational and Aesthetic Impoundments ....................................................... 30 2.4.3 Stream Augmentation ........................................................................................ 30 Groundwater Recharge ................................................................................................... 31 2.5.1 Methods of Groundwater Recharge ................................................................... 32 Surface Spreading ................................................................................ 32 Soil-Aquifer Treatment Systems .......................................................... 35 Vadose Zone Injection .......................................................................... 37 Direct Injection ..................................................................................... 38 2.5.2 Fate of Contaminants in Recharge Systems ..................................................... 38 Particulate Matter ................................................................................. 39 Dissolved Organic Constituents ........................................................... 39 Nitrogen ................................................................................................ 40 Microorganisms .................................................................................... 40 2.5.3 Health and Regulatory Considerations ............................................................... 41 Augmentation of Potable Supplies ................................................................................. 41 2.6.1 Water Quality Objectives for Potable Reuse ..................................................... 42 2.6.2 Surface Water Augmentation for Indirect Potable Reuse ................................... 44 2.6.3 Groundwater Recharge for Indirect Potable Reuse ............................................ 45 2.6.4 Direct Potable Water Reuse .............................................................................. 46 Case Studies ............................................................................................................. 48 2.7.1 Water Reuse at Reedy Creek Improvement District .......................................... 49 2.7.2 Estimating Potable Water Conserved in Altamonte Springs due to Reuse ............................................................................................................ 50 2.7.3 How Using Potable Supplies to Supplement Reclaimed Water Flows can Increase Conservation, Hillsborough County, Florida ....................... 51 2.7.4 Water Reclamation and Reuse Offer an Integrated Approach to Wastewater Treatment and Water Resources Issues in Phoenix, Arizona. ............................................................................................................. 54 2.7.5 Small and Growing Community: Yelm, Washington .......................................... 55 2.7.6 Landscape Uses of Reclaimed Water with Elevated Salinity; El Paso, Texas ................................................................................................. 57 2.7.7 Use of Reclaimed Water in a Fabric Dyeing Industry ........................................ 58 2.7.8 Survey of Power Plants Using Reclaimed Water for Cooling Water .................................................................................................... 58 2.7.9 Agricultural Reuse in Tallahassee, Florida ........................................................ 60 2.7.10 Spray Irrigation at Durbin Creek WWTP Western Carolina Regional Sewer Authority .................................................................................. 60 2.7.11 Agricultural Irrigation of Vegetable Crops: Monterey, California ......................... 62 2.7.12 Water Conserv II: City of Orlando and Orange County, Florida ......................... 62 2.7.13 The Creation of a Wetlands Park: Petaluma, California ..................................... 64 2.7.14 Geysers Recharge Project: Santa Rosa, California .......................................... 64 2.7.15 Advanced Wastewater Reclamation in California .............................................. 65 2.7.16 An Investigation of Soil Aquifer Treatment for Sustainable Water ..................... 66 2.7.17 The City of West Palm Beach, Florida Wetlands-Based Water Reclamation Project .......................................................................................... 67







Page 2.7.18 Types of Reuse Applications in Florida ............................................................. 69 2.7.19 Regionalizing Reclaimed Water in the Tampa Bay Area .................................... 70 References ................................................................................................................................. 71

2.8 3

TECHNICAL ISSUES IN PLANNING WATER REUSE SYSTEMS .......................................................... 77 3.1 Planning Approach ......................................................................................................... 77 3.1.1 Preliminary Investigations ................................................................................. 78 3.1.2 Screening of Potential Markets ......................................................................... 78 3.1.3 Detailed Evaluation of Selected Markets ........................................................... 79 Potential Uses of Reclaimed Water ................................................................................ 80 3.2.1 National Water Use ........................................................................................... 81 3.2.2 Potential Reclaimed Water Demands ................................................................ 81 3.2.3 Reuse and Water Conservation ......................................................................... 85 Sources of Reclaimed Water .......................................................................................... 86 3.3.1 Locating the Sources ........................................................................................ 86 3.3.2 Characterizing the Sources ............................................................................... 87 Level of Treatment and Processes ....................................................... 87 Reclaimed Water Quality ...................................................................... 88 Reclaimed Water Quantity .................................................................... 89 Industrial Wastewater Contributions ..................................................... 90 Treatment Requirements for Water Reuse ..................................................................... 90 3.4.1 Health Assessment of Water Reuse ................................................................. 91 Mechanism of Disease Transmission ................................................... 91 Pathogenic Microorganisms and Health Risks ..................................... 92 Presence and Survival of Pathogens .................................................... 95 Pathogens and Indicator Organisms in Reclaimed Water ..................... 96 Aerosols ............................................................................................... 98 Infectious Disease Incidence Related to Wastewater Reuse ............................................................................. 100 Chemical Constituents ....................................................................... 102 Endocrine Disrupters .......................................................................... 104 3.4.2 Treatment Requirements ................................................................................. 106 Disinfection ........................................................................................ 107 Advanced Wastewater Treatment ....................................................... 109 3.4.3 Reliability in Treatment .................................................................................... 113 EPA Guidelines for Reliability ............................................................. 113 Additional Requirements for Reuse Applications ................................ 115 Operator Training and Competence .................................................... 118 Quality Assurance in Monitoring ......................................................... 118 Seasonal Storage Requirements .................................................................................. 118 3.5.1 Identifying the Operating Parameters .............................................................. 120 3.5.2 Storage to Meet Irrigation Demands ................................................................ 121 3.5.3 Operating without Seasonal Storage ............................................................... 122 Supplemental Water Reuse System Facilities ............................................................. 122 3.6.1 Conveyance and Distribution Facilities ............................................................ 122 Public Health Safeguards ................................................................... 124 Operations and Maintenance .............................................................. 127 3.6.2 Operational Storage ......................................................................................... 128 3.6.3 Alternative Disposal Facilities ......................................................................... 129 Surface Water Discharge .................................................................... 130 Injection Wells .................................................................................... 130








Page Land Application ................................................................................. 131 Environmental Impacts ................................................................................................ 132 3.7.1 Land Use Impacts ........................................................................................... 132 3.7.2 Stream Flow Impacts ...................................................................................... 133 3.7.3 Hydrogeological Impacts ................................................................................. 134 Case Studies ............................................................................................................... 134 3.8.1 Code of Good Practices for Water Reuse ........................................................ 134 3.8.2 Examples of Potable Water Separation Standards from the State of Washington ........................................................................................ 135 3.8.3 An Example of using Risk Assessment to Establish Reclaimed Water Quality .................................................................................................. 136 References ................................................................................................................... 137



3.9 4

WATER REUSE REGULATIONS AND GUIDELINES IN THE U.S. ....................................................... 149 4.1 Inventory of Existing State Regulations and Guidelines ............................................... 149 4.1.1 Reclaimed Water Quality and Treatment Requirements .................................. 153 Unrestricted Urban Reuse ................................................................... 153 Restricted Urban Reuse ...................................................................... 154 Agricultural Reuse - Food Crops ......................................................... 155 Agricultural Reuse – Non-food Crops .................................................. 156 Unrestricted Recreational Reuse ........................................................ 157 Restricted Recreational Reuse ........................................................... 158 Environmental – Wetlands .................................................................. 159 Industrial Reuse ................................................................................. 159 Groundwater Recharge ....................................................................... 160 Potable Reuse ....................................................................... 161 4.1.2 Reclaimed Water Monitoring Requirements ..................................................... 162 4.1.3 Treatment Facility Reliability ........................................................................... 162 4.1.4 Reclaimed Water Storage ................................................................................ 164 4.1.5 Application Rates ............................................................................................ 164 4.1.6 Groundwater Monitoring ................................................................................... 165 4.1.7 Setback Distances for Irrigation ...................................................................... 165 Suggested Guidelines for Water Reuse ........................................................................ 165 Pathogens and Emerging Pollutants of Concern (EPOC) ............................................. 172 Pilot Testing ................................................................................................................. 172 References ................................................................................................................... 173

4.2 4.3 4.4 4.5 5

LEGAL AND INSTITUTIONAL ISSUES ................................................................................................. 175 5.1 Water Rights Law ......................................................................................................... 175 5.1.1 Appropriative Rights System ........................................................................... 176 5.1.2 Riparian Rights System ................................................................................... 176 5.1.3 Water Rights and Water Reuse ....................................................................... 176 5.1.4 Federal Water Rights Issues ........................................................................... 177 Water Supply and Use Regulations .............................................................................. 178 5.2.1 Water Supply Reductions ................................................................................ 178 5.2.2 Water Efficiency Goals .................................................................................... 178 5.2.3 Water Use Restrictions .................................................................................... 179 Wastewater Regulations ............................................................................................... 179 5.3.1 Effluent Quality Limits ..................................................................................... 180 5.3.2 Effluent Flow Limits ......................................................................................... 180




Chapter 5.4 5.5


5.7.6 5.7.7 5.7.8

Safe Drinking Water Act – Source Water Protection .................................................... 180 Land Use and Environmental Regulations .................................................................... 181 5.5.1 General and Specific Plans ............................................................................. 181 5.5.2 Environmental Regulations .............................................................................. 182 Special Environmental Topics ............................................................ 183 5.6 Legal Issues in Implementation .................................................................................... 183 5.6.1 Construction Issues ........................................................................................ 183 System Construction Issues .............................................................. 184 Onsite Construction Issues ................................................................ 184 5.6.2 Wholesaler/Retailer Issues .............................................................................. 184 Institutional Criteria ............................................................................. 185 Institutional Inventory and Assessment .............................................. 185 5.6.3 Customer Issues ............................................................................................. 186 Statutory Customer Responsibilities ................................................... 186 Terms of Service and Commercial Arrangements .............................. 187 5.7 Case Studies ............................................................................................................... 187 5.7.1 Statutory Mandate to Utilize Reclaimed Water: California ......................................................... 187 5.7.2 Administrative Order to Evaluate Feasibility of Water Reclamation: Fallbrook Sanitary District, Fallbrook, California ....................................................................... 188 5.7.3 Reclaimed Water User Agreements Instead of Ordinance: ........................................................................................................... 188 Central Florida 5.7.4 Interagency Agreement Required for Water Reuse: Monterey County Water Recycling Project, Monterey, California .............................................................. 189 5.7.5 Public/Private Partnership to Expand Reuse Program:The City of Orlando, Orange County and The Private Sector – Orlando, Florida ........................................................................................................... 190 Inspection of Reclaimed Water Connections Protect Potable Water Supply: Pinellas County Utilities, Florida ............................................................................................... 191 Oneida Indian Nation/Municipal/State Coordination Leads to Effluent Reuse: Oneida Nation, New York .............................................................................................. 191 Implementing Massachusetts’ First Golf Course Irrigation System Utilizing Reclaimed Water: Yarmouth, Massachusetts ........................................................................... 196 5.8 References ................................................................................................................... 198 FUNDING WATER REUSE SYSTEMS .................................................................................................. 199 6.1 6.2 Decision Making Tools ................................................................................................. 199 Externally Generated Funding Alternatives .................................................................. 200 6.2.1 Local Government Tax-Exempt Bonds ............................................................ 200 6.2.2 State and Federal Financial Assistance .......................................................... 201 State Revolving Fund ......................................................................... 201 Federal Policy .................................................................................... 202 Other Federal Sources ....................................................................... 202 State, Regional, and Local Grant and Loan Support ........................... 203 6.2.3 Capital Contributions ....................................................................................... 203 Internally Generated Funding Alternatives ................................................................... 204 6.3.1 Reclaimed Water User Charges ...................................................................... 204 6.3.2 Operating Budget and Cash Reserves ............................................................. 205 6.3.3 Property Taxes and Existing User Charges .................................................... 205 6.3.4 Public Utility Tax ............................................................................................. 206 6.3.5 Special Assessments or Special Tax Districts ............................................... 206 6.3.6 Impact Fees .................................................................................................... 206




Chapter 6.4 6.5 6.6 6.7

Page Incremental Versus Proportionate Share Costs ........................................................... 206 6.4.1 Incremental Cost Basis ................................................................................... 206 6.4.2 Proportionate Share Cost Basis ...................................................................... 207 Phasing and Participation Incentives ........................................................................... 208 Sample Rates and Fees ............................................................................................... 209 6.6.1 Connection Fees ............................................................................................. 209 6.6.2 User Fees ....................................................................................................... 209 Case Studies ............................................................................................................... 209 6.7.1 Unique Funding Aspects of the Town of Longboat Key Reclaimed Water System ................................................................................................. 209 6.7.2 Financial Assistance in San Diego County, California ..................................... 212 6.7.3 Grant Funding Through the Southwest Florida Water Management District......................................................................................................212 6.7.4 Use of Reclaimed Water to Augment Potable Supplies: An Economic Perspective (California) ............................................................. 213 6.7.5 Impact Fee Development Considerations for Reclaimed Water Projects: Hillsborough County, Florida ............................................................. 215 6.7.6 How Much Does it Cost and Who Pays: A Look at Florida’s Reclaimed Water Rates ................................................................................... 216 6.7.7 Rate Setting for Industrial Reuse in San Marcos, Texas ................................. 218 References ................................................................................................................... 219

6.8 7

PUBLIC INVOLVEMENT PROGRAMS .................................................................................................. 221 7.1 7.2 7.3 Why Public Participation? ............................................................................................ 221 7.1.1 Informed Constituency .................................................................................... 221 Defining the “Public” ..................................................................................................... 222 Overview of Public Perceptions ................................................................................... 222 7.3.1 Residential and Commercial Reuse in Tampa, Florida .................................... 223 7.3.2 A Survey of WWTP Operators and Managers ................................................. 223 7.3.3 Public Opinion in San Francisco, California .................................................... 223 7.3.4 Clark County Sanitation District Water Reclamation Opinion Surveys ........................................................................................................... 223 Involving the Public in Reuse Planning ........................................................................ 224 7.4.1 General Requirements for Public Participation ................................................ 226 Public Advisory Groups or Task Forces ............................................. 228 Public Participation Coordinator .......................................................... 229 7.4.2 Specific Customer Needs ................................................................................ 229 Urban Systems .................................................................................. 229 Agricultural Systems .......................................................................... 229 Reclaimed Water for Potable Purposes .............................................. 230 7.4.3 Agency Communication .................................................................................. 230 7.4.4 Public Information Through Implementation .................................................... 231 7.4.5 Promoting Successes ..................................................................................... 231 Case Studies ............................................................................................................... 231 7.5.1 Accepting Produce Grown with Reclaimed Water: Monterey, California ......................................................................................................... 231 7.5.2 Water Independence in Cape Coral – An Implementation Update in 2003 ........................................................................................................... 232 7.5.3 Learning Important Lessons When Projects Don’t Go as Planned .................. 234 San Diego, California .......................................................................... 234 Public Outreach May not be Enough: Tampa, Florida ........................ 235




Chapter 7.5.4

Page Pinellas County, Florida Adds Reclaimed Water to Three R’s of Education ........................................................................................................ 236 7.5.5 Yelm, Washington, A Reclaimed Water Success Story .................................. 237 7.5.6 Gwinnett County, Georgia – Master Plan Update Authored by Public ......................................................................................................... 237 7.5.7 AWWA Golf Course Reclaimed Water Market Assessment ............................ 238 References ................................................................................................................... 240

7.6 8

WATER REUSE OUTSIDE THE U.S. .................................................................................................... 241 8.1 8.2 Main Characteristics of Water Reuse in the World ....................................................... 241 Water Reuse Drivers .................................................................................................... 242 8.2.1 Increasing Water Demands ............................................................................. 243 8.2.2 Water Scarcity ................................................................................................ 243 8.2.3 Environmental Protection and Public Health ................................................... 245 Water Reuse Applications – Urban and Agriculture ...................................................... 245 Planning Water Reuse Projects .................................................................................... 246 8.4.1 Water Supply and Sanitation Coverage ........................................................... 247 8.4.2 Technical Issues ............................................................................................. 247 Water Quality Requirements ............................................................... 249 Treatment Requirements .................................................................... 252 8.4.3 Institutional Issues .......................................................................................... 253 8.4.4 Legal Issues .................................................................................................... 253 Water Rights and Water Allocation ..................................................... 253 Public Health and Environmental Protection ....................................... 254 8.4.5 Economic and Financial Issues ...................................................................... 254 Examples of Water Reuse Programs Outside the U.S. ................................................ 255 8.5.1 Argentina ......................................................................................................... 255 8.5.2 Australia .......................................................................................................... 255 Aurora, Australia ................................................................................. 255 Mawson Lakes, Australia ................................................................... 256 Virginia Project, South Australia ......................................................... 256 8.5.3 Belgium ........................................................................................................... 257 8.5.4 Brazil ........................................................................................................... 258 Sao Paulo, Brazil ................................................................................ 258 Sao Paulo International Airport, Brazil ................................................ 259 8.5.5 Chile ........................................................................................................... 259 8.5.6 China ........................................................................................................... 260 8.5.7 Cyprus ........................................................................................................... 261 8.5.8 Egypt ........................................................................................................... 261 8.5.9 France ........................................................................................................... 262 8.5.10 Greece ........................................................................................................... 262 8.5.11 India ........................................................................................................... 263, India ................................................................................ 264 8.5.12 Iran ........................................................................................................... 264 8.5.13 Israel ........................................................................................................... 265 8.5.14 Italy ........................................................................................................... 266 8.5.15 Japan ........................................................................................................... 267 8.5.16 Jordan ........................................................................................................... 267 8.5.17 Kuwait ........................................................................................................... 268 8.5.18 Mexico ........................................................................................................... 269 8.5.19 Morocco .......................................................................................................... 271

8.3 8.4




Page, Morocco ................................................................................. 271 Namibia ........................................................................................................... 272 Oman ........................................................................................................... 272 Pakistan .......................................................................................................... 273 Palestinian National Authority ......................................................................... 274 Peru ........................................................................................................... 275 Saudi Arabia .................................................................................................... 275 Singapore ........................................................................................................ 276 South Africa .................................................................................................... 277 Spain ........................................................................................................... 278 Brava, Spain ............................................................................ 278, Spain .................................................................................... 279 de l’Emporda Natural Preserve, Spain ............................. 279 City of Victoria, Spain ................................................................. 279 8.5.29 Sweden ........................................................................................................... 279 8.5.30 Syria ........................................................................................................... 280 8.5.31 Tunisia ........................................................................................................... 280 8.5.32 United Arab Emirates ...................................................................................... 282 8.5.33 United Kingdom ............................................................................................... 282 8.5.34 Yemen ........................................................................................................... 283 8.5.35 Zimbabwe ........................................................................................................ 284 References ........................................................................................................... 284 8.5.20 8.5.21 8.5.22 8.5.23 8.5.24 8.5.25 8.5.26 8.5.27 8.5.28


STATE REUSE REGULATIONS AND GUIDELINES ................................................................ 289 STATE WEBSITES ........................................................................................................... 441 ABBREVIATIONS AND ACRONYMS ....................................................................................... 443 INVENTORY OF RECLAIMED WATER PROJECTS ................................................................ 445


Table 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 2-13 2-14 2-15 3-1 3-2 3-3 3-4 3-5 Page Typical Cycles of Concentration (COC) ............................................................................................ 14 Florida and California Reclaimed Water Quality ................................................................................ 15 North Richmond Water Reclamation Plant Sampling Requirements ................................................. 18 Industrial Process Water Quality Requirements ............................................................................... 19 Pulp and Paper Process Water Quality Requirements ...................................................................... 19 Efficiencies for Different Irrigation Systems ..................................................................................... 22 Recommended Limits for Constituents in Reclaimed Water for Irrigation ......................................... 25 Comparison of Major Engineering Factors for Engineered Groundwater Recharge .......................................................................................................................................... 33 Water Quality at Phoenix, Arizona SAT System .............................................................................. 37 Factors that May Influence Virus Movement to Groundwater ........................................................... 41 Physical and Chemical Sampling Results from the San Diego Potable Reuse Study .................................................................................................................................... 47 San Diego Potable Reuse Study: Heavy Metals and Trace Organics Results .................................. 48 Average Discharge Rates and Quality of Municipal Reclaimed Effluent in El Paso and Other Area Communities .............................................................................................. 57 Treatment Processes for Power Plant Cooling Water ....................................................................... 59 Field Sites for Wetlands/SAT Research ........................................................................................... 67 Designer Waters ............................................................................................................................... 89 Infectious Agents Potentially Present in Untreated Domestic Wastewater ....................................... 93 Ct Requirements for Free Chlorine and Chlorine Dioxide to Achieve 99 Percent Inactivation of E. Coli Compared to Other Microorganisms ................................................. 95 Microorganism Concentrations in Raw Wastewater .......................................................................... 96 Microorganism Concentrations in Secondary Non-Disinfected Wastewater ...................................... 96


Table 3-6 3-7 3-8 3-9 3-10 3-11 12-12 3-13a 3-13b 3-14 3-15 3-16 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 4-9 4-10 4-11 4-12 4-13

Page Typical Pathogen Survival Times at 20-30 oC .................................................................................. 97 Pathogens in Untreated and Treated Wastewater ............................................................................. 98 Summary of Florida Pathogen Monitoring Data ................................................................................ 99 Operational Data for Florida Facilities ............................................................................................... 99 Some Suggested Alternative Indicators for Use in Monitoring Programs ........................................ 100 Inorganic and Organic Constituents of Concern in Water Reclamation and Reuse ...................................................................................................................................... 103 Examples of the Types and Sources of Substances that have been Reported as Potential Endocrine Disrupting Chemicals .................................................................. 105 Microfiltration Removal Performance Data ..................................................................................... 112 Reverse Osmosis Performance Data ............................................................................................. 112 Summary of Class I Reliability Requirements ................................................................................ 115 Water Reuse Required to Equal the Benefit of Step Feed BNR Upgrades ...................................... 131 Average and Maximum Conditions for Exposure ............................................................................ 137 Summary of State Reuse Regulations and Guidelines ................................................................... 152 Number of States with Regulations or Guidelines for Each Type of Reuse Application .................. 151 Unrestricted Urban Reuse ............................................................................................................... 153 Restricted Urban Reuse .................................................................................................................. 154 Agricultural Reuse – Food Crops .................................................................................................... 155 Agricultural Reuse – Non-Food Crops ............................................................................................. 157 Unrestricted Recreational Reuse .................................................................................................... 158 Restricted Recreational Reuse ....................................................................................................... 158 Environmental Reuse – Wetlands ................................................................................................... 159 Industrial Reuse ............................................................................................................................. 160 Groundwater Recharge ................................................................................................................... 161 Indirect Potable Reuse ................................................................................................................... 163 Suggested Guidelines for Water Reuse .......................................................................................... 167


Table 5-1 6-1 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 7-1 7-2 7-3 7-4 8-1 8-2 8-3 8-4 8-5 8-6 8-7 8-8 8-9

Page Some Common Institutional Patterns ............................................................................................. 185 Credits to Reclaimed Water Costs .................................................................................................. 208 User Fees for Existing Urban Reuse Systems ............................................................................... 210 Discounts for Reclaimed Water Use in California ........................................................................... 209 Estimated Capital and Maintenance Costs for Phase IVA With and Without Federal and State Reimbursements ............................................................................................... 214 Cost Estimate for Phase I of the GWR System ............................................................................. 214 Total Annual Benefits ..................................................................................................................... 215 Reclaimed Water Impact Fees ....................................................................................................... 216 Average Rates for Reclaimed Water Service in Florida .................................................................. 217 Percent Costs Recovered Through Reuse Rates ........................................................................... 218 Positive and Negative Responses to Potential Alternatives for Reclaimed Water .............................................................................................................................................. 224 Survey Results for Different Reuse ................................................................................................ 227 Trade Reactions and Expectations Regarding Produce Grown with Reclaimed Water ............................................................................................................................ 232 Chronology of WICC Implementation .............................................................................................. 233 Sources of Water in Several Countries ........................................................................................... 242 Wastewater Flows, Collection, and Treatment in Selected Countries in 1994 (Mm3/year) ............................................................................................................................. 247 Summary of Water Quality Parameters of Concern for Water Reuse ............................................. 250 Summary of Water Recycling Guidelines and Mandatory Standards in the United States and Other Countries ....................................................................................... 251 Life-Cycle Cost of Typical Treatment Systems for a 40,000 Population-Equivalent Flow of Wastewater ..................................................................................... 254 Summary of Australian Reuse Projects .......................................................................................... 257 Water Demand and Water Availability per Region in the Year 2000 ................................................ 259 Effluent Flow Rates from Wastewater Treatment Plants in Metropolitan Sao Paulo .................................................................................................................. 259 Water Reuse at the Sao Paulo International Airport ........................................................................ 260




8-10 8-11 8-12 8-13 8-14 8-15 8-16 8-17

Major Reuse Projects ..................................................................................................................... 263 Uses of Reclaimed Water in Japan ................................................................................................ 268 Water Withdrawal in Kuwait ............................................................................................................ 269 Reclaimed Water Standards in Kuwait ............................................................................................ 270 Effluent Quality Standards from the Sulaibiya Treatment and Reclamation Plant .......................................................................................................................... 270 Plant Performance Parameters at the Drarga Wastewater Treatment Plant ................................... 273 Reclaimed Water Standards for Unrestricted Irrigation in Saudi Arabia .......................................... 276 Wastewater Treatment Plants in the Cities of Syria ....................................................................... 281


Figure 1-1 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 2-13 2-14 2-15 2-16 2-17 2-18 Page Estimated and Projected Urban Population in the World ...................................................................... 2 Potable and Nonpotable Water Use – Monthly Historic Demand Variation, Irvine Ranch Water District, California .................................................................................................. 9 Potable and Nonpotable Water Use – Monthly Historic Demand Variation, St. Petersburg, Florida ......................................................................................................................... 9 Cooling Tower .................................................................................................................................... 14 Comparison of Agricultural Irrigation, Public/Domestic, and Total Freshwater Withdrawals ..................................................................................................................... 20 Agricultural Reuse Categories by Percent in California ...................................................................... 20 Three Engineered Methods for Groundwater Recharge ...................................................................... 32 Schematic of Soil-Aquifer Treatment Systems .................................................................................. 36 Contaminants Regulated by the National Primary Drinking Water Regulations ........................................................................................................................................ 43 Water Resources at RCID .................................................................................................................. 50 Altamonte Springs Annual Potable Water Demands per Capita ......................................................... 51 Estimated Potable Water Conserved Using Best LEM Method .......................................................... 52 Estimated Potable Water Conserved Using the CCM Method ............................................................ 52 Estimated Potable Water Conserved Using Both Methods ................................................................ 53 Estimated Raw Water Supply vs. Demand for the 2002 South/Central Service Area ...................................................................................................................................... 53 North Phoenix Reclaimed Water Service Area ................................................................................... 56 Durbin Creek Storage Requirements as a Function of Irrigated Area ................................................. 61 Project Flow Path ............................................................................................................................... 68 Growth of Reuse in Florida ................................................................................................................. 69


Figure 2-19 3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 3-10 3-11 3-12 3-13 3-14 3-15 3-16 3-17 3-18 3-19 3-20 3-21 3-22 3-23 4-1

Page Available Reclaimed Water in Pasco, Pinellas, and Hillsborough Counties ........................................ 70 Phases of Reuse Program Planning .................................................................................................. 77 1995 U.S. Fresh Water Demands by Major Uses ............................................................................... 81 Fresh Water Source, Use, and Disposition ........................................................................................ 82 Wastewater Treatment Return Flow by State, 1995 ........................................................................... 83 Total Withdrawals ............................................................................................................................... 83 Average Indoor Water Usage (Total = 69.3 gpcd) .............................................................................. 84 Potable and Reclaimed Water Usage in St. Petersburg, Florida ........................................................ 86 Three Configuration Alternatives for Water Reuse Systems .............................................................. 87 Reclaimed Water Supply vs. Irrigation Demand ................................................................................. 90 Generalized Flow Sheet for Wastewater Treatment ......................................................................... 107 Particle Size Separation Comparison Chart ..................................................................................... 109 Average Monthly Rainfall and Pan Evaporation ............................................................................... 120 Average Pasture Irrigation Demand and Potential Supply ................................................................ 121 Example of Multiple Reuse Distribution System .............................................................................. 124 Reclaimed Water Advisory Sign ....................................................................................................... 125 Florida Separation Requirements for Reclaimed Water Mains .......................................................... 126 Anticipated Daily Reclaimed Water Demand Curve vs. Diurnal Reclaimed Water Flow Curve ............................................................................................................................. 129 TDS Increase Due to Evaporation for One Year as a Function of Pond Depth ............................................................................................................................................... 130 Orange County, Florida, Redistribution Constructed Wetland ........................................................... 132 A Minimum 5-Foot (1.5 m) Horizontal Pipe Separation Coupled with and 18-Inch (46 cm) Vertical Separation ................................................................................................. 135 Irrigation Lateral Separation ............................................................................................................. 136 Lateral Crossing Requirements ........................................................................................................ 136 Parallel Water – Lateral Installation .................................................................................................. 136 California Water Reuse by Type (Total 358 mgd) ............................................................................. 150


Figure 4-2 6-1 6-2 7-1 7-2 7-3 7-4 7-5 8-1 8-2a 8-2b 8-3a 8-3b 8-4

Page California Water Reuse by Type (Total 584 mgd) ............................................................................. 150 Comparison of Reclaimed Water and Potable Water Rates in Southwest Florida .............................................................................................................................................. 211 Comparison of Rate Basis for San Marcos Reuse Water ................................................................. 218 Public Beliefs and Opinions ............................................................................................................. 225 Support of Recycled Water Program Activities ................................................................................ 225 Survey Results for Different Reuse .................................................................................................. 226 Public Participation Program for Water Reuse System Planning ..................................................... 227 Survey Responses ........................................................................................................................... 239 World Populations in Cities .............................................................................................................. 243 Countries with Chronic Water Stress Using Non-Renewable Resources .......................................... 244 Countries with Moderate Water Stress ............................................................................................. 244 Countries with Total Water Supply and Sanitation Coverage Over 80 Percent ....................................................................................................................................... 248 Countries with Total Water Supply and Sanitation Coverage Over 50 Percent ....................................................................................................................................... 248 Future Demand for Irrigation Water Compared with Potential Availability of Reclaimed Water for Irrigation in the West Bank, Palestine ............................................................. 274




The Guidelines for Water Reuse debuted in 1980 and was updated in 1992. Since then, water reuse practices have continued to develop and evolve. This edition of the Guidelines offers new information and greater detail about a wide range of reuse applications and introduces new health considerations and treatment technologies supporting water reuse operations. It includes an updated inventory of state reuse regulations and an expanded coverage of water reuse practices in countries outside of the U. S. Dozens of reuse experts contributed text and case studies to highlight how reuse applications can and do work in the real world. The 2004 Guidelines for Water Reuse document was built upon information generated by the substantial research and development efforts and extensive demonstration projects on water reuse practices throughout the world, ranging from potable reuse to wetlands treatment. Some of the most useful sources drawn upon in developing this update include: proceedings from American Water Works Association/Water Environment Federal (AWWA/WEF) Water Reuse conferences, WEF national conferences, and WateReuse conferences; selected articles from WEF and AWWA journals; materials provided by the Guidelines review committee; and a series of WERF reports on water reclamation and related subjects published by the National Research Counsel/National Academy of Sciences, WEF/AWWA. Please note that the statutes and regulations described in this document may contain legally binding requirements. The summaries of those laws provided here, as well as the approaches suggested in this document, do not substitute for those statutes or regulations, nor are these guidelines themselves any kind of regulation. This document is intended to be solely informational and does not impose legally-binding requirements on EPA, States, local or tribal governments, or members of the public. Any EPA decisions regarding a particular water reuse project will be made based on the applicable statutes and regulations. EPA will continue to review and update these guidelines as necessary and appropriate.

This version of the Guidelines for Water Reuse document was developed by Camp Dresser & McKee Inc. (CDM) through a Cooperative Research and Development Agreement (CRADA) with the U.S. Environmental Protection Agency (EPA) under the direction of Robert L. Matthews, P.E., DEE as Project Director and David K. Ammerman, P.E. as Project Manager, with hands-on assistance from Karen K. McCullen, P.E., Valerie P. Going, P.E., and Lisa M. Prieto, E.I. of CDM. These developers also wish to acknowledge the help of Dr. James Crook, P.E., Dr. Bahman Sheikh; Julia Forgas, Gloria Booth, and Karen Jones of CDM, as well as; MerriBeth Farnham of Farnham and Associates, Inc. and Perry Thompson of Thompson and Thompson Graphics Inc. Partial funding to support the preparation of the updated Guidelines document was provided by EPA and the U.S. Agency for International Development (USAID). The Guidelines document was prepared by CDM with contributions from more 100 participants from other consulting firms, state and federal agencies, local water and wastewater authorities, and academic institutions. We wish to acknowledge the direction, advice, and suggestions of the sponsoring agencies, notably: Mr. Robert K. Bastian and Dr. John Cicmanec of EPA, as well as Dr. Peter McCornick, P.E., Dr. John Austin, and Mr. Dan Deely of USAID. We would also like to thank the many technical reviewers who so painstakingly reviewed this document. Our special thanks go to the following group of our colleagues who took the time to share their life experiences and technical knowledge to make these Guidelines relevant and user-friendly. The contributors are broken up into three categories: those who directly authored and/or edited text, those who attended the technical review meeting (TRC), and those who were general reviewers. Some contributors are listed more than once to demonstrate their multiple roles in the preparation of the document.


Please note that the listing of these contributors in no way identifies them as supporters of this document or represents their ideas and/or opinions on the subject. These persons are the leaders in the field and their expertise from every angle has added to the depth and breadth of the document. The following colleagues contributed in the way of editing or submitting text and/or case studies. The asterisks annotate those who were part of the international efforts. *Dr. Felix P. Amerasinghe International Water Management Institute Sri Lanka Daniel Anderson, P.E. CDM West Palm Beach, Florida Anthony J. Andrade Southwest Florida Water Management District Brooksville, Florida Laura Andrews, P.E. CDM Sarasota, Florida Ed Archuleta El Paso Water Utilities El Paso, Texas *Dr. Takashi Asano University of California at Davis Davis, California Richard W. Atwater Inland Empire Utilities Agency Rancho Cucamonga, California Shelly Badger City of Yelm Yelm, Washington John E. Balliew, P.E. El Paso Water Utilities El Paso, Texas Kristina Bentson Katz and Associates La Jolla, California Randy Bond SE Farm Facility - City of Tallahassee Tallahassee, Florida

*Brandon G. Braley, P.E. CDM International Cambridge, Massachusetts Dennis Cafaro Resource Conservation Systems Bonita Springs, Florida Kasey Brook Christian University of Florida Gainesville, Florida Dr. Russell Christman University of North Carolina – Chapel Hill Chapel Hill, North Carolina *Max S. Clark, P.E. CDM International Hong Kong Pat Collins Parsons Santa Rosa, California Aimee Conroy Phoenix Water Services Department Phoenix, Arizona Dr. Robert C. Cooper BioVir Laboratories, Inc. Benicia, California Robin Cort Parsons Engineering Science, Inc. Oakland, California *Geoffrey Croke PSI-Delta Australia Dr. James Crook, P.E. Environmental Consultant Norwell, Massachusetts Phil Cross Woodard & Curran, Inc./Water Conserv II Winter Garden, Florida Katharine Cupps, P.E. Washington Department of Ecology Olympia, Washington *Jeroen H. J. Ensink International Water Management Institute India


William Everest Orange County Water Department Fountain Valley, California David Farabee Environmental Consultant Sarasota, Florida Dr. Peter Fox National Center for Sustainable Water Supply Arizona State University Tempe, Arizona Monica Gasca Los Angeles County Sanitation Districts Whittier, California Jason M. Gorrie, P.E. CDM Tampa, Florida Brian J. Graham, P.E., DEE United Water Carlsbad, California Gary K. Grinnell, P.E. Las Vegas Valley Water District Las Vegas, Nevada Michael Gritzuk Phoenix Water Services Department Phoenix, Arizona *Dr. Ross E. Hagan USAID Egypt Raymond E. Hanson, P.E. Orange County Utilities Water Reclamation Division Orlando, Florida Earle Hartling Los Angeles County Sanitation Districts Whittier, California Roy L. Herndon Orange County Water District Fountain Valley, California *Dr. Ivanhildo Hesponhol Polytechnic School, University of São Paolo Brazil

Lauren Hildebrand, P.E. Western Carolina Regional Sewer Authority Greenville, South Carolina Dr. Helene Hilger University of North Carolina – Charlotte Charlotte, North Carolina Stephen M. Hoffman CDM Orlando, Florida Keith Israel Monterey Regional Water Pollution Control Agency Monterey, California Joe Ann Jackson PBS&J Orlando, Florida Robert S. Jaques Monterey Regional Water Pollution Control Agency Monterey, California Laura Johnson East Bay Municipal Utility District Oakland, California Leslie C. Jones, P.E. CDM Charlotte, North Carolina Sara Katz Katz & Associates La Jolla, California Diane Kemp CDM Sarasota, Florida *Mario Kerby Water Resources Sustainability Project Morocco *Dr. Valentina Lazarova Suez Environment - CIRSEE France Thomas L. Lothrop, P.E., DEE City of Orlando Orlando, Florida


Peter M. MacLaggan, P.E., Esq. Poseidon Resources Corporation San Diego, California Rocco J. Maiellano Evesham Municipal Utilities Authority Evesham, New Jersey *Chris Marles SA Water Australia Ted W. McKim, P.E. Reedy Creek Energy Services Lake Buena Vista, Florida Dianne B. Mills CDM Charlotte, North Carolina Dr. Thomas M. Missimer, PG CDM Ft. Myers, Florida Dr. Seiichi Miyamoto Texas A&M University/Agricultural Research Center El Paso, Texas *Dr. Rafael Mujeriego Universidad Politécnica de Cataluña Spain Richard Nagel, P.E. West and Central Basin Municipal Water Districts Carson, California Margaret Nellor Los Angeles County Sanitation Districts Whittier, California David Ornelas, P.E. El Paso Water Utilities El Paso, Texas Ray T. Orvin Western Carolina Regional Sewer Authority Greenville, South Carolina *Francis Pamminger Yarra Valley Water Ltd. Australia Jeffrey F. Payne, P.E., DEE CDM Charlotte, North Carolina

Paul R. Puckorius Puckorius & Associates, Inc. Evergreen, Colorado William F. Quinn, Jr. El Paso Water Utilities El Paso, Texas Roderick D. Reardon, P.E., DEE CDM Orlando, Florida Craig L. Riley, P.E. State of Washington Department of Health Spokane, Washington Martha Rincón Los Angeles County Sanitation Districts Whittier, California Dr. Joan Rose Michigan State University East Lansing, Michigan Eric Rosenblum City of San Jose San Jose, California Steve Rossi Phoenix Water Services Department Phoenix, Arizona Dr. A. Charles Rowney, P.E. CDM Orlando, Florida Robert W. Sackellares GA-Pacific Corporation Atlanta, Georgia Richard H. Sakaji California Department of Health Services Berkeley, California *Dr. Lluis Sala Consorci de la Costa Brava Spain *Ahmad Sawalha USAID West Bank & Gaza Dr. Larry N. Schwartz CDM Orlando, Florida


*Dr. Christopher Scott, P.E. International Water Management Institute India Kathy F. Scott Southwest Florida Water Management District Brooksville, Florida *Naief Saad Seder Jordan Valley Authority - Ministry of Water & Irrigation Jordan Dr. David L. Sedlak University of California - Berkeley Berkeley, California *Manel Serra Consorci de la Costa Brava Spain *Dr. Bahman Sheikh Water Reuse Consulting San Francisco, CA Wayne Simpson, P.E. Richard A. Alaimo & Associates Mount Holly, New Jersey Dr. Theresa R. Slifko Orange County Government Orlando, Florida Michael P. Smith, P.E. CDM Tampa, Florida Melissa J. Stanford National Regulatory Research Institute Columbus, Ohio Keith Stoeffel Washington Department of Ecology Spokane, Washington Stephen C. Stratton National Council for Air and Stream Improvement, Inc. Research Triangle Park, North Carolina Robert D. Teegarden, P.E. Orange County Utilities Engineering Division Orlando, Florida

Andy Terrey Phoenix Water Services Department Phoenix, Arizona Hal Thomas City of Walla Walla Public Works Walla Walla, Washington Sandra Tripp, P.E. CDM Charlotte, North Carolina Joseph V. Towry City of St. Petersburg Water Systems Maintenance Division St. Petersburg, Florida Jay Unwin National Council for Air and Stream Improvement, Inc. Research Triangle Park, North Carolina Joe Upchurch Western Carolina Regional Sewer Authority Greenville, South Carolina *Daniel van Oosterwijck Yarra Valley Water Australia Florence T. Wedington, P.E. East Bay Municipal Utility District Oakland, California Nancy J. Wheatley, J.D. Water Resources Strategies Siasconset, Massachusetts Lee P. Wiseman, P.E., DEE CDM Orlando, Florida *Ralph Woolley Brisbane City Council Australia David Young CDM Cambridge, Massachusetts


The following persons attended the TRC in Phoenix, Arizona. Dr. Barnes Bierck, P.E. Environmental Engineering Consultant Chapel Hill, North Carolina Dr. Herman Bouwer U.S. Water Conservation Laboratory Phoenix, Arizona Dennis Cafaro Resource Conservation Systems Bonita Springs, Florida Lori Ann Carroll Sarasota County Environmental Services Sarasota, Florida Tracy A. Clinton Carollo Engineers Walnut Creek, California Katharine Cupps, P.E. Washington Department of Ecology Olympia, Washington Gary K. Grinnell, P.E. Las Vegas Valley Water District Las Vegas, Nevada Dr. Helene Hilger University of North Carolina - Charlotte Charlotte, North Carolina Robert S. Jaques Monterey Regional Water Pollution Control Agency Monterey, California Heather Kunz CH2M Hill Atlanta, Georgia Keith Lewinger Fallbrook Public Utility District Fallbrook, California Craig Lichty, P.E. Kennedy/Jenks Consultants San Francisco, California Jeff Mosher WateReuse Association Alexandria, Virginia

Richard Nagel, P.E. West and Central Basin Municipal Water Districts Carson, California Joan Oppenheimer MWH Pasadena, California Jerry D. Phillips, P.E. Jacobs Civil, Inc. Orlando, Florida Alan H. Plummer, P.E., DEE Alan Plummer Associates, Inc. Fort Worth, Texas Fred Rapach, R.E.P. Palm Beach County Water Utilities Department West Palm Beach, Florida Roderick D. Reardon, P.E., DEE CDM Orlando, Florida Alan E. Rimer, P.E., DEE Black & Veatch International Company Cary, North Carolina Todd L. Tanberg, P.E. Pinellas County Utilities Clearwater, Florida Dr. Donald M. Thompson, P.E. CDM Jacksonville, Florida Don Vandertulip, P.E. Pape-Dawson Engineers, Inc. San Antonio, Texas Michael P. Wehner, MPA, REHS Orange County Water District Fountain Valley, California Nancy J. Wheatley, J.D. Water Resource Strategies Siasconset, Massachusetts


Robert Whitley Whitley, Burchett and Associates Walnut Creek, California Ronald E. Young, P.E., DEE Elsinore Valley Municipal Water District Lake Elsinore, California The following contributors reviewed portions or all of the text. Earnest Earn Georgia Department of Natural Resources Atlanta, Georgia Christianne Ferraro, P.E. Florida Department of Environmental Protection Orlando, Florida Patrick Gallagher CDM Cambridge, Massachusetts Robert H. Hultquist State of California Department of Health Services Sacramento, California Frank J. Johns II, P.E. Arcadis G&M Inc. Highlands Ranch, Colorado C. Robert Mangrum, P.E. CH2M Hill Deerfield Beach, Florida Kate Martin Narasimhan Consulting Services Irvine, California David MacIntyre PB Water Orlando, Florida Dr. Choon Nam Ong National University of Singapore Singapore Henry Ongerth Consulting Engineer Berkeley, California David R. Refling, P.E., DEE Boyle Engineering Corporation Orlando, Florida

The following individuals also provided review comments on behalf of the U.S. EPA: Howard Beard EPA Office of Water/Office of Groundwater and Drinking Water Dr. Phillip Berger EPA Office of Water/Office of Groundwater and Drinking Water Bob Brobst EPA Region 8 Denver, Colorado Glendon D. Deal USDA/RUS David Del Porto Ecological Engineering Group, Inc. Dr. Jorg Drewes Colorado School of Mines Alan Godfree United Utilities Water PLC Jim Goodrich EPA ORD/NRMRL Cincinnati, Ohio Dr. Hend Gorchev EPA Office of Water/Office of Science and Technology Dr. Fred Hauchman EPA ORD/NHEERL Research Triangle Park, North Carolina Mark Kellet Northbridge Environmental Dr. Robert A. Rubin UDSDA Extension Service NCSU on detail to EPA OWM Ben Shuman USDA/RUS Carrie Wehling EPA Office of General Counsel/Water Law Office Nancy Yoshikawa EPA Region 9 San Francisco, California



CHAPTER 1 Introduction
The world’s population is expected to increase dramatically between now and the year 2020 - and with this growth will come an increased need for water to meet various needs, as well as an increased production of wastewater. Many communities throughout the world are approaching, or have already reached, the limits of their available water supplies; water reclamation and reuse have almost become necessary for conserving and extending available water supplies. Water reuse may also present communities with an alternate wastewater disposal method as well as provide pollution abatement by diverting effluent discharge away from sensitive surface waters. Already accepted and endorsed by the public in many urban and agricultural areas, properly implemented nonpotable reuse projects can help communities meet water demand and supply challenges without any known significant health risks. any kind of regulation. In addition, neither the U.S. Environmental Protection Agency (EPA) nor the U.S. Agency for International Development (USAID) proposes standards for water reuse in this publication or any other. This document is intended to be solely informational and does not impose legally-binding requirements on EPA, states, local or tribal governments, or members of the public. Any EPA decisions regarding a particular water reuse project will be made based on the applicable statutes and regulations. EPA will continue to review and update these guidelines as necessary and appropriate. In states where standards do not exist or are being revised or expanded, the Guidelines can assist in developing reuse programs and appropriate regulations. The Guidelines will also be useful to consulting engineers and others involved in the evaluation, planning, design, operation, or management of water reclamation and reuse facilities. In addition, an extensive chapter on international reuse is included to provide background information and discussion of relevant water reuse issues for authorities in other countries where reuse is being planned, developed, and implemented. In the U.S., water reclamation and reuse standards are the responsibility of state agencies.


Objectives of the Guidelines

Water reclamation for nonpotable reuse has been adopted in the U.S. and elsewhere without the benefit of national or international guidelines or standards. Twenty-five states currently have regulations regarding water reuse. The World Health Organization (WHO) guidelines for agricultural irrigation reuse (dated 1989) are under revision (World Health Organization Website, 2003). The primary purpose of the 2004 EPA Guidelines for Water Reuse is to present and summarize water reuse guidelines, with supporting information, for the benefit of utilities and regulatory agencies, particularly in the U.S. The Guidelines cover water reclamation for nonpotable urban, industrial, and agricultural reuse, as well as augmentation of potable water supplies through indirect reuse. Direct potable reuse is also covered, although only briefly since it is not practiced in the U.S. Please note that the statutes and regulations described in this document may contain legally binding requirements. The summaries of those laws provided here, as well as the approaches suggested in this document, do not substitute for those statutes or regulations, nor are these guidelines themselves


Water Demands and Reuse

Growing urbanization in water-scarce areas of the world exacerbates the situation of increasing water demands for domestic, industrial, commercial, and agricultural purposes. Figure 1-1 demonstrates the rapid growth rate of the urban population worldwide. In the year 2000, 2.85 billion people (out of a worldwide population of 6.06 billion) were living in urban regions (United Nations Secretariat, 2001). This increasing urban population results in a growing water demand to meet domestic, commercial, industrial, and agricultural needs. Coupled with depleting fresh water sources, utility directors and managers are faced with the challenge to supply water to a growing customer base.


Figure 1-1

Estimated and Projected Urban Population in the World

the year 2010. Likewise, California has a statutory goal of doubling its current use by 2010. Texas currently reuses approximately 230 mgd (8.7 x 105 m3) and Arizona reuses an estimated 200 mgd (7.6 x 105 m3). While these 4 states account for the majority of the water reuse in the U.S., several other states have growing water reuse programs including Nevada, Colorado, Georgia, North Carolina, Virginia, and Washington. At least 27 states now have water reclamation facilities, and the majority of states have regulations dealing with water reuse (Gritzuk, 2003).


Source Substitution

Adapted from: United Nations Secretariat, 2001.

The U.S. Bureau of Reclamation is developing a program, Water 2025, to focus attention on the emerging need for water. Explosive population growth in urban areas of the western U.S., along with a growing demand for available water supplies for environmental and recreational uses, is conflicting with the national dependence on water for the production of food and fiber from western farms and ranches (Department of the Interior/Bureau of Reclamation, 2003). The goals of Water 2025 are to:

Under the broad definition of water reclamation and reuse, sources of reclaimed water may range from industrial process waters to the tail waters of agricultural irrigation systems. For the purposes of these Guidelines, however, the sources of reclaimed water are limited to the effluent generated by domestic wastewater treatment facilities (WWTFs). The use of reclaimed water for nonpotable purposes offers the potential for exploiting a “new” resource that can be substituted for existing potable sources. This idea, known as “source substitution” is not new. In fact, the United Nations Economic and Social Council enunciated a policy in 1958 that, “No higher quality water, unless there is a surplus of it, should be used for a purpose that can tolerate a lower grade.” Many urban, commercial, and industrial uses can be met with water of less than potable water quality. With respect to potable water sources, EPA policy states, “Because of human frailties associated with protection, priority should be given to selection of the purest source” (EPA, 1976). Therefore, when the demand exceeds the capacity of the purest source, and additional sources are unavailable or available only at a high cost, lower quality water can be substituted to serve the nonpotable purposes. Since few areas enjoy a surplus of high quality water, and demand often exceeds capacity, many urban residential, commercial, and industrial uses can be satisfied with water of less than potable water quality. In many instances, treated wastewater may provide the most economical and/or available substitute source for such uses as irrigation of lawns, parks, roadway borders, and medians; air conditioning and industrial cooling towers; stack gas scrubbing; industrial processing; toilet flushing; dust control and construction; cleaning and maintenance, including vehicle washing; scenic waters and fountains; and environmental and recreational purposes. The economics of source substitution with reclaimed water are site-specific and dependent on the marginal costs of new sources of high-quality water and the costs of waste-

Facilitate a more forward-looking focus on waterstarved areas of the country Help stretch or increase water supplies, satisfy the demands of growing populations, protect environmental needs, and strengthen regional, tribal, and local economies Provide added environmental benefits to many watersheds, rivers, and streams Minimize water crises in critical watersheds by improving the environment and addressing the effects of drought on important economies Provide a balanced, practical approach to water management for the next century





Meanwhile, water reuse in the U.S. is a large and growing practice. An estimated 1.7 billion gallons (6.4 million m3) per day of wastewater is reused, and reclaimed water use on a volume basis is growing at an estimated 15 percent per year. In 2002, Florida reclaimed 584 mgd (2.2 x 106 m3) of its wastewater while California ranked a close second, with an estimated total of 525 mgd (2.0 x 106 m3) of reclaimed water used each day. Florida has an official goal of reclaiming 1 billion gallons per day by


water treatment and disposal. Understandably, the construction of reclaimed water transmission and distribution lines to existing users in large cities is expensive and disruptive. As a result, wastewater reclamation and reuse will continue to be most attractive in serving new residential, commercial, and industrial areas of a city, where the installation of dual distribution systems would be far more economical than in already developed areas. Use of reclaimed water for agricultural purposes near urban areas can also be economically attractive. Agricultural users are usually willing to make long-term commitments, often for as long as 20 years, to use large quantities of reclaimed water instead of fresh water sources. One potential scenario is to develop a new reclaimed water system to serve agricultural needs outside the city with the expectation that when urban development replaces agricultural lands in time, reclaimed water use can be shifted from agricultural to new urban development.

reclaimed water is often distributed at a flat rate or at minimal cost to the users. However, where reclaimed water is intended to be used as a water resource, metering is appropriate to provide an equitable method for distributing the resource, limiting overuse, and recovering costs. In St. Petersburg, Florida, disposal was the original objective; however, over time the reclaimed water became an important resource. Meters, which were not provided initially, are being considered to prevent wasting of the reclaimed water.


Treatment and Water Quality Considerations


Pollution Abatement

While the need for additional water supply in arid and semi-arid areas has been the impetus for numerous water reclamation and reuse programs, many programs in the U.S. were initiated in response to rigorous and costly requirements to remove nitrogen and phosphorus for effluent discharge to surface waters. By eliminating effluent discharges for all or even a portion of the year through water reuse, a municipality may be able to avoid or reduce the need for the costly nutrient removal treatment processes. For example, the South Bay Water Recycling Project in San Jose, California, provides reclaimed water to 1.3 million area residents. By reusing this water instead of releasing it to the San Francisco Bay, San Jose has avoided a sewer moratorium that would have had a devastating impact on the Silicon Valley economy (Gritzuk, 2003). The purposes and practices may differ between water reuse programs developed strictly for pollution abatement and those developed for water resources or conservation benefits. When systems are developed chiefly for the purpose of land treatment or disposal, the objective is to treat and/or dispose of as much effluent on as little land as possible; thus, application rates are often greater than irrigation demands. On the other hand, when the reclaimed water is considered a valuable resource (i.e., an alternative water supply), the objective is to apply the water according to irrigation needs. Differences are also apparent in the distribution of reclaimed water for these different purposes. Where disposal is the objective, meters are difficult to justify, and

Water reclamation and nonpotable reuse typically require conventional water and wastewater treatment technologies that are already widely practiced and readily available in many countries throughout the world. When discussing treatment for a reuse system, the overriding concern continues to be whether the quality of the reclaimed water is appropriate for the intended use. Higher level uses, such as irrigation of public-access lands or vegetables to be consumed without processing, require a higher level of wastewater treatment and reliability prior to reuse than will lower level uses, such as irrigation of forage crops and pasture. For example, in urban settings, where there is a high potential for human exposure to reclaimed water used for landscape irrigation, industrial purposes, and toilet flushing, the reclaimed water must be clear, colorless, and odorless to ensure that it is aesthetically acceptable to the users and the public at large, as well as to assure minimum health risk. Experience has shown that facilities producing secondary effluent can become water reclamation plants with the addition of filtration and enhanced disinfection processes. A majority of the states have published treatment standards or guidelines for one or more types of water reuse. Some of these states require specific treatment processes; others impose effluent quality criteria, and some require both. Many states also include requirements for treatment reliability to prevent the distribution of any reclaimed water that may not be adequately treated because of a process upset, power outage, or equipment failure. Dual distribution systems (i.e., reclaimed water distribution systems that parallel a potable water system) must also incorporate safeguards to prevent crossconnections of reclaimed water and potable water lines and the misuse of reclaimed water. For example, piping, valves, and hydrants are marked or color-coded (e.g. purple pipe) to differentiate reclaimed water from potable water. Backflow prevention devices are installed, and hose bibs on reclaimed water lines may be prohibited to preclude the likelihood of incidental human misuse. A strict


industrial pretreatment program is also necessary to ensure the reliability of the biological treatment process by excluding the discharge of potentially toxic levels of pollutants to the sanitary sewer system. Wastewater treatment facilities receiving substantial amounts of highstrength industrial wastes may be limited in the number and type of suitable reuse applications.

The document has been arranged by topic, devoting separate chapters to each of the key technical, financial, legal and institutional, and public involvement issues that a reuse planner might face. A separate chapter has also been provided to discuss reuse applications outside of the U.S. These chapters are:


Overview of the Guidelines

This document, the Guidelines for Water Reuse, is an update of the Guidelines for Water Reuse developed for EPA by Camp Dresser & McKee Inc. (CDM) and published by EPA in 1992 (and initially in 1980). In May 2002, EPA contracted with CDM through a Cooperative Research and Development Agreement (CRADA) to update the EPA/USAID Guidelines for Water Reuse (EPA/625/R-92/004: Sept 1992). As with the 1992 Guidelines, a committee, made up of national and international experts in the field of water reclamation and related subjects, was established to develop new text, update case studies, and review interim drafts of the document. However, unlike the 1992 version, the author and reviewer base was greatly expanded to include approximately 75 contributing authors and an additional 50 reviewers. Major efforts associated with the revisions to this edition of the Guidelines include:
„ Updating the state reuse regulations matrix and add-

Chapter 2, Types of Reuse Applications – A discussion of reuse for urban, industrial, agricultural, recreational and habitat restoration/enhancement, groundwater recharge, and augmentation of potable supplies. Direct potable reuse is also briefly discussed. Chapter 3, Technical Issues in Planning Water Reuse Systems – An overview of the potential uses of reclaimed water, the sources of reclaimed water, treatment requirements, seasonal storage requirements, supplemental system facilities (including conveyance and distribution), operational storage, and alternative disposal systems. lines in the U.S. – A summary of existing state standards and regulations as well as recommended guidelines.


„ Chapter 4, Water Reuse Regulations and Guide-


ing a list of state contacts

Chapter 5, Legal and Institutional Issues – An overview of reuse ordinances, user agreements, water rights, franchise law, and case law. Chapter 6, Funding Water Reuse Systems – A discussion of funding and cost recovery options for reuse system construction and operation, as well as management issues for utilities. Chapter 7, Public Involvement Programs – An outline of strategies for educating and involving the public in water reuse system planning and reclaimed water use. Chapter 8, Water Reuse Outside the U.S. – A summary of the issues facing reuse planners outside of the U.S., as well as a comprehensive review of the variety of reuse projects and systems around the world.

Updating U.S. Geological Survey (USGS) information on national water use and reuse practices Expanding coverage of indirect potable reuse issues, emphasizing the results of recent studies and practices associated with using reclaimed water to augment potable supplies Expanding coverage of industrial reuse issues outside of the U.S





„ Expanding coverage of reuse projects and practices


„ Adding more case studies to illustrate experience in

all areas of water reclamation
„ Expanding the discussion of health issues to include

emerging chemicals and pathogens

Updating the discussion of treatment technologies applicable to water reclamation project funding mechanisms

„ Updating information on economics, user rates, and




Department of the Interior/Bureau of Reclamation. Water 2025: Preventing Conflict and Crisis in the West. [Updated 6 June 2003; cited 30 July 2003]. Available from Gritzuk, M. 2003. Testimony-The Importance of Water Reuse in the 21st Century, presented by Michael Gritzuk to the Subcommittee on Water & Power Committee on Resources, U.S. House of Representatives, March 27, 2003. United Nations Secretariat – Population Division – Department of Economic and Social Affairs. 2001. World Urbanization Prospects: The 1999 Revision. ST/ESA/ SER.A/194, USA. U.S. Environmental Protection Agency. 1976. National Interim Primary Drinking Water Regulations. EPA 570/ 9-76-003, Washington, D.C. World Heath Organization (WHO). Water Sanitation and Health (WSH). [Updated 2003; cited 31 July 2003]. Available from



CHAPTER 2 Types of Reuse Applications
Chapter 2 provides detailed explanations of major reuse application types. These include:
„ Urban „ Ornamental landscape uses and decorative water fea„ Industrial „ Agricultural „ „ Environmental and recreational „ Groundwater recharge „ Augmentation of potable supplies „ Commercial uses such as vehicle washing facilities,

laundry facilities, window washing, and mixing water for pesticides, herbicides, and liquid fertilizers tures, such as fountains, reflecting pools, and waterfalls Dust control and concrete production for construction projects

„ Fire protection through reclaimed water fire hydrants „ Toilet and urinal flushing in commercial and industrial

buildings Quantity and quality requirements are considered for each reuse application, as well as any special considerations necessary when reclaimed water is substituted for more traditional sources of water. Case studies of reuse applications are provided in Section 2.7. Key elements of water reuse that are common to most projects (i.e., supply and demand, treatment requirements, storage, and distribution) are discussed in Chapter 3. Urban reuse can include systems serving large users. Examples include parks, playgrounds, athletic fields, highway medians, golf courses, and recreational facilities. In addition, reuse systems can supply major water-using industries or industrial complexes as well as a combination of residential, industrial, and commercial properties through “dual distribution systems.” A 2-year field demonstration/research garden compared the impacts of irrigation with reclaimed versus potable water for landscape plants, soils, and irrigation components. The comparison showed few significant differences; however, landscape plants grew faster with reclaimed water (Lindsey et al., 1996). But such results are not a given. Elevated chlorides in the reclaimed water provided by the City of St. Petersburg have limited the foliage that can be irrigated (Johnson, 1998). In dual distribution systems, the reclaimed water is delivered to customers through a parallel network of distribution mains separate from the community’s potable water distribution system. The reclaimed water distribution system becomes a third water utility, in addition to wastewater and potable water. Reclaimed water systems are operated, maintained, and managed in a manner similar to the potable water system. One of the oldest municipal dual distribution systems in the U.S., in St. Petersburg,


Urban Reuse

Urban reuse systems provide reclaimed water for various nonpotable purposes including:
„ Irrigation of public parks and recreation centers, ath-

letic fields, school yards and playing fields, highway medians and shoulders, and landscaped areas surrounding public buildings and facilities
„ Irrigation of landscaped areas surrounding single-family

and multi-family residences, general wash down, and other maintenance activities
„ Irrigation of landscaped areas surrounding commer-

cial, office, and industrial developments
„ Irrigation of golf courses


Florida, has been in operation since 1977. The system provides reclaimed water for a mix of residential properties, commercial developments, industrial parks, a resource recovery power plant, a baseball stadium, and schools. The City of Pomona, California, first began distributing reclaimed water in 1973 to California Polytechnic University and has since added 2 paper mills, roadway landscaping, a regional park and a landfill with an energy recovery facility. During the planning of an urban reuse system, a community must decide whether or not the reclaimed water system will be interruptible. Generally, unless reclaimed water is used as the only source of fire protection in a community, an interruptible source of reclaimed water is acceptable. For example, the City of St. Petersburg, Florida, decided that an interruptible source of reclaimed water would be acceptable, and that reclaimed water would provide backup only for fire protection. If a community determines that a non-interruptible source of reclaimed water is needed, then reliability, equal to that of a potable water system, must be provided to ensure a continuous flow of reclaimed water. This reliability could be ensured through a municipality having more than one water reclamation plant to supply the reclaimed water system, as well as additional storage to provide reclaimed water in the case of a plant upset. However, providing the reliability to produce a non-interruptible supply of reclaimed water will have an associated cost increase. In some cases, such as the City of Burbank, California, reclaimed water storage tanks are the only source of water serving an isolated fire system that is kept separate from the potable fire service. Retrofitting a developed urban area with a reclaimed water distribution system can be expensive. In some cases, however, the benefits of conserving potable water may justify the cost. For example, a water reuse system may be cost-effective if the reclaimed water system eliminates or forestalls the need to:

tem is a requirement of the community’s land development code. In 1984, the City of Altamonte Springs, Florida, enacted the requirement for developers to install reclaimed water lines so that all properties within a development are provided service. This section of the City’s land development code also stated, “The intent of the reclaimed water system is not to duplicate the potable water system, but rather to complement each other and thereby provide the opportunity to reduce line sizes and looping requirements of the potable water system” (Howard, Needles, Tammen, and Bergendoff, 1986a). The Irvine Ranch Water District in California studied the economic feasibility of expanding its urban dual distribution system to provide reclaimed water to high-rise buildings for toilet and urinal flushing. The study concluded that the use of reclaimed water was feasible for flushing toilets and urinals and priming floor drain traps for buildings of 6 stories and higher (Young and Holliman, 1990). Following this study, an ordinance was enacted requiring all new buildings over 55 feet (17 meters) high to install a dual distribution system for flushing in areas where reclaimed water is available (Irvine Ranch Water District, 1990). The City of Avalon, California, conducted a feasibility study to assess the replacement of seawater with reclaimed water in the City’s nonpotable toilet flushing/fire protection distribution system. The study determined that the City would save several thousand dollars per year in amortized capital and operation and maintenance costs by switching to reclaimed water (Richardson, 1998).


Reclaimed Water Demand

Obtain additional water supplies from considerable distances seawater desalination)

„ Treat a raw water supply source of poor quality (e.g.,

The daily irrigation demand for reclaimed water generated by a particular urban system can be estimated from an inventory of the total irrigable acreage to be served by the reclaimed water system and the estimated weekly irrigation rates. These rates are determined by such factors as local soil characteristics, climatic conditions, and type of landscaping. In some states, recommended weekly irrigation rates may be available from water management agencies, county or state agricultural agents, or irrigation specialists. Reclaimed water demand estimates must also take into account any other permitted uses for reclaimed water within the system. An estimate of the daily irrigation demand for reclaimed water can also be made by evaluating local water billing records. For example, in many locations, second water meters measure the volume of potable water used outside the home, primarily for irrigation. An evaluation of the water billing records in Orlando, Florida, showed the average irrigation demand measured on the resi-

„ Treat wastewater to stricter surface water discharge

requirements In developing urban areas, substantial cost savings may be realized by installing a dual distribution system as developments are constructed. A successful way to accomplish this is to stipulate that connecting to the sys-


dential second meter was approximately 506 gpd (1.9 m3/d), compared to 350 gpd (1.3 m3/d) on the first meter, which measured the amount of water for in-house use (CDM, 2001). This data indicates that a 59 percent reduction in residential potable water demand could be accomplished if a dual distribution system were to provide irrigation service. Water use records can also be used to estimate the seasonal variation in reclaimed water demand. Figure 2-1 and Figure 2-2 show the historic monthly variation in the potable and nonpotable water demand for the Irvine Ranch Water District in California and St. Petersburg, Florida, respectively. Although the seasonal variation in demand is different between the 2 communities, both show a similar trend in the seasonal variation between potable and nonpotable demand. Even though St. Petersburg and Irvine Ranch meet much of the demand for irrigation with reclaimed water, the influence of these uses can still be seen in the potable water demands. For potential reclaimed water users, such as golf courses, that draw irrigation water from onsite wells, an evaluation of the permitted withdrawal rates or pumping records can be used to estimate their reclaimed water needs.

Figure 2-2.

Potable and Nonpotable Water Use - Monthly Historic Demand Variation, St. Petersburg, Florida

Figure 2-1.

Potable and Nonpotable Water Use - Monthly Historic Demand Variation, Irvine Ranch Water District, California

estimated by determining the volume of water required to maintain a desired water elevation in the impoundment. For those systems using reclaimed water for toilet flushing as part of their urban reuse system, water use records can again be used to estimate demand. According to Grisham and Fleming (1989), toilet flushing can account for up to 45 percent of indoor residential water demand. In 1991, the Irvine Ranch Water District began using reclaimed water for toilet flushing in high-rise office buildings. Potable water demands in these buildings have decreased by as much as 75 percent due to the reclaimed water use (IRWD, 2003).


Reliability and Public Health Protection

In assessing the reuse needs of an urban system, demands for uses other than irrigation must also be considered. These demands are likely to include industrial, commercial, and recreational uses. Demands for industrial users, as well as commercial users, such as car washes, can be estimated from water use or billing records. Demands for recreational impoundments can be

In the design of an urban reclaimed water distribution system, the most important considerations are the reliability of service and protection of public health. Treatment to meet appropriate water quality and quantity requirements and system reliability are addressed in Section 3.4. The following safeguards must be considered during the design of any dual distribution system:
„ Assurance that the reclaimed water delivered to the

customer meets the water quality requirements for the intended uses



Prevention of improper operation of the system water lines

„ Prevention of cross-connections with potable

„ Prevention of improper use of nonpotable water

larly for large cities, operational storage facilities may be located at appropriate locations in the system and/or near the reuse sites. When located near the pumping facilities, ground or elevated tanks may be used; when located within the system, operational storage is generally elevated. Sufficient storage to accommodate diurnal flow variation is essential to the operation of a reclaimed water system. The volume of storage required can be determined from the daily reclaimed water demand and supply curves. Reclaimed water is normally produced 24 hours per day in accordance with the diurnal flow at the water reclamation plant and may flow to ground storage to be pumped into the system or into a clear well for high-lift pumping to elevated storage facilities. In order to maintain suitable water quality, covered storage is preferred to preclude biological growth and maintain chlorine residual. Refer to Section 3.5.2 for a discussion of operational storage. Since variations in the demand for reclaimed water occur seasonally, large volumes of seasonal storage may be needed if all available reclaimed water is to be used, although this may not be economically practical. The selected location of a seasonal storage facility will also have an effect on the design of the distribution system. In areas where surface storage may be limited due to space limitations, aquifer storage and recovery (ASR) could prove to be a viable enhancement to the system. Hillsborough County, Florida has recovered ASR water, placed it into the reuse distribution system, and is working to achieve a target storage volume of 90 million gallons (340,700 m3) (McNeal, 2002). A detailed discussion of seasonal storage requirements is provided in Section 3.5. The design of an urban distribution system is similar in many respects to a municipal potable water distribution system. Materials of equal quality for construction are recommended. System integrity should be assured; however, the reliability of the system need not be as stringent as a potable water system unless reclaimed water is being used as the only source of fire protection. No special measures are required to pump, deliver, and use the water. No modifications are required because reclaimed water is being used, with the exception that equipment and materials must be clearly identified. For service lines in urban settings, different materials may be desirable for more certain identification. The design of distribution facilities is based on topographical conditions as well as reclaimed water demand requirements. If topography has wide variations, multilevel systems may have to be used. Distribution mains must be sized to provide the peak hourly demands at a pressure adequate for the user being served. Pressure

To avoid cross connections, all above-ground appurtenances and equipment associated with reclaimed water systems must be clearly marked. National color standards have not been established, but most manufacturers, counties, and cities have adopted the color purple for reclaimed water lines. The State of Florida has accepted Pantone 522C as the color of choice for reclaimed water material designation. Florida also requires signs to be posted with specific language in both English and Spanish identifying the resource as nonpotable. Additional designations include using the international symbol for “Do Not Drink” on all materials, both surface and subsurface, to minimize potential cross connections. A more detailed discussion of distribution safeguards and cross connection control measures is presented in Section 3.6.1, Conveyance and Distribution Facilities.


Design Considerations

Urban water reuse systems have 2 major components: 1. Water reclamation facilities 2. Reclaimed water distribution system, including storage and pumping facilities Water Reclamation Facilities

Water reclamation facilities must provide the required treatment to meet appropriate water quality standards for the intended use. In addition to secondary treatment, filtration, and disinfection are generally required for reuse in an urban setting. Because urban reuse usually involves irrigation of properties with unrestricted public access or other types of reuse where human exposure to the reclaimed water is likely, reclaimed water must be of a higher quality than may be necessary for other reuse applications. In cases where a single large customer needs a higher quality reclaimed water, the customer may have to provide additional treatment onsite, as is commonly done with potable water. Treatment requirements are presented in Section 3.4.2. Distribution System

Reclaimed water operational storage and high-service pumping facilities are usually located onsite at the water reclamation facility. However, in some cases, particu-


requirements for a dual distribution system vary depending on the type of user being served. Pressures for irrigation systems can be as low as 10 psi (70 kPa) if additional booster pumps are provided at the point of delivery, and maximum pressures can be as high as 100 to 150 psi (700 to 1,000 kPa). The peak hourly rate of use, which is a critical consideration in sizing the delivery pumps and distribution mains, may best be determined by observing and studying local urban practices and considering time of day and rates of use by large users to be served by the system. The following design peak factors have been used in designing urban reuse systems:
System Altamonte Springs, Florida (HNTB, 1986a) Apopka, Florida (Godlewski et al., 1990) Aurora, Colorado (Johns et al., 1987) Boca Raton, Florida (CDM, 1990a) Irvine Ranch Water District, California (IRWD, 1991) - Landscape Irrigation - Golf Course and Agricultural Irrigation San Antonio Water System (SAWS), Texas (SAWS Website, 2004) Sea Pines, South Carolina (Hirsekorn and Ellison, 1987) St. Petersburg, Florida (CDM, 1987) Peaking Factor 2.90 4.00 2.50 2.00

and a peak factor of 2.0 for agricultural and golf course irrigation systems (IRWD, 1991). The peak factor for landscape irrigation is higher because reclaimed water use is restricted to between 9 p.m. and 6 a.m. This restriction may not apply to agricultural or golf course use. Generally, there will be “high-pressure” and “low-pressure” users on an urban reuse system. The high-pressure users receive water directly from the system at pressures suitable for the particular type of reuse. Examples include residential and landscape irrigation, industrial processes and cooling water, car washes, fire protection, and toilet flushing in commercial and industrial buildings. The low-pressure users receive reclaimed water into an onsite storage pond to be repumped into their reuse system. Typical low-pressure users are golf courses, parks, and condominium developments that use reclaimed water for irrigation. Other low-pressure uses include the delivery of reclaimed water to landscape or recreational impoundments, or industrial or cooling tower sites that have onsite tanks for blending and/or storing water. Typically, urban dual distribution systems operate at a minimum pressure of 50 psi (350 kPa), which will satisfy the pressure requirements for irrigation of larger landscaped areas such as multi-family complexes, and offices, commercial, and industrial parks. A minimum pressure of 50 psi (350 kPa) should also satisfy the requirements of car washes, toilet flushing, construction dust control, and some industrial uses. Based on requirements of typical residential irrigation equipment, a minimum delivery pressure of 30 psi (210 kPa) is used for the satisfactory operation of in-ground residential irrigation systems. For users who operate at higher pressures than other users on the system, additional onsite pumping will be required to satisfy the pressure requirements. For example, golf course irrigation systems typically operate at higher pressures (100 to 200 psi or 700 kPa to 1,400 kPa), and if directly connected to the reclaimed water system, will likely require a booster pump station. Repumping may be required in high-rise office buildings using reclaimed water for toilet flushing. Additionally, some industrial users may operate at higher pressures. The design of a reuse transmission system is usually accomplished through the use of computer modeling, with portions of each of the sub-area distribution systems representing demand nodes in the model. The demand of each node is determined from the irrigable acreage tributary to the node, the irrigation rate, and the daily irrigation time period. Additional demands for uses other than irrigation, such as fire flow protection, toilet flushing, and

6.80 2.00 1.92 2.00 2.25

The wide range of peaking factors reflects the nature of the demands being served, the location of the reuse system (particularly where irrigation is the end use), and the experience of the design engineers. San Antonio’s low peaking factor was achieved by requiring onsite storage for customer demands greater than 100 acre-feet per year (62 gpm). These large customers were allowed to receive a peak flow rate based on a 24-hour delivery of their peak month demand in July. This flat rate delivery and number of large irrigation customers resulted in a low system peaking factor. For reclaimed water systems that include fire protection as part of their service, fire flow plus the maximum daily demand should be considered when sizing the distribution system. This scenario is not as critical in sizing the delivery pumps since it will likely result in less pumping capacity, but is critical in sizing the distribution mains because fire flow could be required at any point in the system, resulting in high localized flows. The Irvine Ranch Water District Water Resources Master Plan recommends a peak hourly use factor of 6.8 when reclaimed water is used for landscape irrigation


industrial uses must also be added to the appropriate node. The 2 most common methods of maintaining system pressure under widely varying flow rates are: (1) constantspeed supply pumps and system elevated storage tanks, which maintain essentially consistent system pressures, or (2) constant-pressure, variable-speed, high-service supply pumps, which maintain a constant system pressure while meeting the varying demand for reclaimed water by varying the pump speed. While each of these systems has advantages and disadvantages, either system will perform well and remains a matter of local choice. The dual distribution system of the City of Altamonte Springs, Florida operates with constant-speed supply pumps and 2 elevated storage tanks, and pressures range between 55 and 60 psi (380 kPa and 410 kPa). The urban system of the Marin Municipal Water District, in California, operates at a system pressure of 50 to 130 psi (350 kPa and 900 kPa), depending upon elevation and distance from the point of supply, while Apopka, Florida operates its reuse system at a pressure of 60 psi (410 kPa). The system should be designed with the flexibility to institute some form of usage control when necessary and provide for the potential resulting increase in the peak hourly demand. One such form of usage control would be to vary the days per week that schools, parks, golf courses, and residential areas are irrigated. In addition, large users, such as golf courses, will have a major impact on the shape of the reclaimed water daily demand curve, and hence on the peak hourly demand, depending upon how the water is delivered to them. The reclaimed water daily demand curve may be “flattened” and the peak hourly demand reduced if the reclaimed water is discharged to golf course ponds over a 24-hour period or during the daytime hours when demand for residential landscape irrigation is low. These methods of operation can reduce peak demands, thereby reducing storage requirements, pumping capacities, and pipe diameters. This in turn, can reduce construction cost.

robust distribution system, the increased pipe size and storage required for fire flows results in increased residence time within the distribution system, and a corresponding potential reduction in reclaimed water quality. In Rouse Hill, an independent community near Sydney, Australia, reclaimed water lines are being sized to handle fire flows, allowing potable line sizes to be reduced. Due to a shortage of potable water supplies, the City of Cape Coral, Florida, designed a dual distribution system supplied by reclaimed water and surface water that provides for fire protection and urban irrigation. This practice was possible due to the fact that nonpotable service, including the use of reclaimed water for fire protection, was part of the planning of the development before construction. However, these benefits come at the cost of elevating the reclaimed water system to an essential service with reliability equal to that of the potable water system. This in turn, requires redundancy and emergency power with an associated increase in cost. For these reasons, the City has decided to not include fire protection in its future reclaimed water distribution systems. This decision was largely based on the fact that the inclusion of fire protection limited operations of the reclaimed water distribution system. Specifically, the limited operations included the lack of ability to reduce the operating pressure and to close valves in the distribution system. In some cases, municipalities may be faced with replacing existing potable water distribution systems, because the pipe material is contributing to water quality problems. In such instances, consideration could be given to converting the existing network into a nonpotable distribution system capable of providing fire protection and installing a new, smaller network to handle potable demands. Such an approach would require a comprehensive cross connection control process to ensure all connections between the potable and nonpotable system were severed. Color-coding of below-ground piping also poses a challenge. To date, no community has attempted such a conversion. More often, the primary means of fire protection is the potable water system, with reclaimed water systems providing an additional source of water for fire flows. In the City of St. Petersburg, Florida, fire protection is shared between potable and reclaimed water. In San Francisco, California, reclaimed water is part of a dual system for fire protection that includes high-rise buildings. Reclaimed water is also available for fire protection in the Irvine Ranch Water District, California. In some cases, site-specific investigations may determine that reclaimed water is the most cost-effective means of providing fire protection. The City of Livermore, California, determined that using reclaimed water for fire protection at airport hangers and a wholesale warehouse store would be less expensive than up-


Using Reclaimed Water for Fire Protection

Reclaimed water may be used for fire protection, but this application requires additional design efforts (Snyder et al., 2002). Urban potable water distribution systems are typically sized based on fire flow requirements. In residential areas, this can result in 6-inch diameter pipes to support fire demands where 2-inch diameter pipes may be sufficient to meet potable needs. Fire flow requirements also increase the volume of water required to be in storage at any given time. While this results in a very


grading the potable water system (Johnson and Crook, 1998).


Industrial Reuse

Industrial reuse has increased substantially since the early 1990s for many of the same reasons urban reuse has gained popularity, including water shortages and increased populations, particularly in drought areas, and legislation regarding water conservation and environmental compliance. To meet this increased demand, many states have increased the availability of reclaimed water to industries and have installed the necessary reclaimed water distribution lines. As a result, California, Arizona, Texas, Florida, and Nevada have major industrial facilities using reclaimed water for cooling water and process/ boiler-feed requirements. Utility power plants are ideal facilities for reuse due to their large water requirements for cooling, ash sluicing, rad-waste dilution, and flue gas scrubber requirements. Petroleum refineries, chemical plants, and metal working facilities are among other industrial facilities benefiting from reclaimed water not only for cooling, but for process needs as well.

1970s. The Rawhide Energy Station utility power plant in Fort Collins, Colorado, has used about 245 mgd (10,753 l/s) of reclaimed water for once through cooling of condensers since the 1980s. The reclaimed water is added to a body of water and the combined water is used in the once-through cooling system. After one-time use, the water is returned to the original water source (lake or river). Recirculating Evaporative Cooling Water Systems

Recirculating evaporative cooling water systems use water to absorb process heat, and then transfer the heat by evaporation. As the cooling water is recirculated, makeup water is required to replace water lost through evaporation. Water must also be periodically removed from the cooling water system to prevent a buildup of dissolved solids in the cooling water. There are 2 common types of evaporative cooling systems that use reclaimed water: (1) cooling towers and (2) spray ponds. Cooling Tower Systems


Cooling Water

For the majority of industries, cooling water is the largest use of reclaimed water because advancements in water treatment technologies have allowed industries to successfully use lesser quality waters. These advancements have enabled better control of deposits, corrosion, and biological problems often associated with the use of reclaimed water in a concentrated cooling water system. There are 2 basic types of cooling water systems that use reclaimed water: (1) once-through and (2) recirculating evaporative. The recirculating evaporative cooling water system is the most common reclaimed water system due to its large water use and consumption by evaporation. Once-Through Cooling Water Systems

As implied by the name, once-through cooling water systems involve a simple pass of cooling water through heat exchangers. There is no evaporation, and therefore, no consumption or concentration of the cooling water. Very few once-through cooling systems use reclaimed water and, in most instances, are confined to locations where reuse is convenient, such as where industries are located near an outfall. For example, Bethlehem Steel Company in Baltimore, Maryland, has used 100 mgd (4,380 l/s) of treated wastewater effluent from Baltimore’s Back River Wastewater Treatment Facility for processes and once-through cooling water system since the early

Like all recirculating evaporative systems, cooling water towers are designed to take advantage of the absorption and transfer of heat through evaporation. Over the past 10 years, cooling towers have increased in efficiency so that only 1.75 percent of the recirculated water is evaporated for every 10 °F (6 oC) drop in process water heat, decreasing the need to supplement with makeup water. Because water is evaporated, the dissolved solids and minerals will remain in the recirculated water. These solids must be removed or treated to prevent accumulation on the cooling equipment as well as the cooling tower. This removal is accomplished by discharging a portion of the cooling water, referred to as blow-down water. The blow-down water is usually treated by a chemical process and/or a filtration/softening/clarification process before disposal. Buildup of total dissolved solids can occur within the reclamation/industrial cooling system if the blowdown waste stream, with increased dissolved solids, is recirculated between the water reclamation plant and the cooling system. The Curtis Stanton Energy Facility in Orlando, Florida, receives reclaimed water from an Orange County wastewater facility for cooling water. Initially, the blow-down water was planned to be returned to the wastewater facility. However, this process would eventually increase the concentration of dissolved solids in the reclaimed water to a degree that it could not be used as cooling water in the future. So, as an alternative, the blow-down water is crystallized at the Curtis Stanton facility and disposed of at a landfill. The City of San Marcos, Texas, identified the


following indirect impacts associated with receiving the blow-down water back at their wastewater treatment plant: reduced treatment capacity, impact to the biological process, and impact to the plant effluent receiving stream (Longoria et al., 2000). To avoid the impacts to the wastewater treatment plant, the City installed a dedicated line to return the blow-down water directly to the UV disinfection chamber. Therefore, there was no loss of plant capacity or impact to the biological process. The City has provided increased monitoring of the effluent-receiving stream to identify any potential stream impacts. Cooling tower designs vary widely. Large hyperbolic concrete structures, as shown in Figure 2-3, range from 250 to 400 feet (76 to 122 meters) tall and 150 to 200 feet (46 to 61 meters) in diameter, and are common at utility power plants. These cooling towers can recirculate approximately 200,000 to 500,000 gpm (12,600 to 31,500 l/s) of water and evaporate approximately 6,000 to 15,000 gpm (380 to 950 l/s) of water. Smaller cooling towers can be rectangular boxes constructed of wood, concrete, plastic, and/or fiberglass reinforced plastic with circular fan housings for each cell. Each cell can recirculate (cool) approximately 3,000 to 5,000 gpm (190 to 315 l/s). Petroleum refineries, chemical plants, steel mills, smaller utility plants, and other processing industries can have as many as 15 cells in a single cooling tower, recirculating approximately 75,000 gpm (4,700 l/s). Commercial air conditioning cooling tower systems can recirculate as little as 100 gpm (6 l/s) to as much as 40,000 gpm (2,500 l/s).

The cycles of concentration (COC) are defined as the ratio of a given ion or compound in the cooling tower water compared to the identical ion or compound in the makeup water. For example, if the sodium chloride level in the cooling tower water is 200 mg/l, and the same compound in the makeup water is 50 mg/l, then the COC is 200 divided by 50, or 4, often referred to as 4 cycles. Industries often operate their cooling towers at widely different cycles of concentration as shown in Table 2-1. The reason for such variations is that the cooling water is used for different applications such as wash water, ash sluicing, process water, etc. Spray Ponds

Spray ponds are usually small lakes or bodies of water where warmed cooling water is directed to nozzles that Table 2-1. Typical Cycles of Concentration (COC)
Industry Utilities Fossil Nuclear Petroleum Refineries Chemical Plants Steel Mills HVAC Paper Mills Typica l COC 5-8 6-10 6-8 8-10 3-5 3-5 5-8

Figure 2-3.

Cooling Tower


spray upward to mix with air. This spraying causes evaporation, but usually only produces a 3 to 8 º F drop in temperature. Spray ponds are often used by facilities, such as utility power plants, where minimal cooling is needed and where the pond can also be incorporated into either decorative fountains or the air conditioning system. Reclaimed water has some application related to spray ponds, usually as makeup water, since there are often restrictions on discharging reclaimed water into lakes or ponds. In addition, there is a potential for foaming within the spray pond if only reclaimed water is used. For example, the City of Ft. Collins, Colorado, supplies reclaimed water to the Platte River Power Authority for cooling its 250 megawatt (MW) Rawhide Energy Station. The recirculation cooling system is a 5.2-billion-gallon (20-million-m3) lake used to supply 170,000 gpm (107,000 l/s) to the condenser and auxiliary heat exchangers. Reclaimed water is treated to reduce phosphate and other contaminants, and then added to the freshwater lake. Cooling Water Quality Requirements

The City of Las Vegas and Clark County Sanitation District uses 90 mgd (3,940 l/s) of secondary effluent to supply 35 percent of the water demand in power generating stations operated by the Nevada Power Company. The power company provides additional treatment consisting of 2-stage lime softening, filtration, and chlorination prior to use as cooling tower makeup. A reclaimed water reservoir provides backup for the water supply. The Arizona Public Service 1,270-MW Palo Verde nuclear power plant is located 55 miles from Phoenix, Arizona, and uses almost all of the City of Phoenix and area cities’ reclaimed water at an average rate of 38,000 gpm (2,400 l/s). In a partnership between the King County Department of Metropolitan Services (Seattle, Washington), the Boeing Company, and Puget Sound Power and Light Company, a new 600,000-square-foot (55,740-m2) Customer Service Training Center is cooled using chlorinated secondary effluent (Lundt, 1996). In Texas, The San Antonio Water System (SAWS) has a provision in its service agreement that allows for adjustment in the reclaimed water rates for cooling tower use if the use of reclaimed water results in fewer cycles of concentration. Corrosion Concerns

The most frequent water quality problems in cooling water systems are corrosion, biological growth, and scaling. These problems arise from contaminants in potable water as well as in reclaimed water, but the concentrations of some contaminants in reclaimed water may be higher than in potable water. Table 2-2 provides some reclaimed water quality data from Florida and California. In Burbank, California, about 5 mgd (219 l/s) of municipal secondary effluent has been successfully utilized for cooling water makeup in the City’s power generating plant since 1967. The reclaimed water is of such good quality that with the addition of chlorine, acid, and corrosion inhibitors, the reclaimed water quality is nearly equal to that of freshwater. There are also numerous petroleum refineries in the Los Angeles area in California that have used reclaimed water since 1998 as 100 percent of the makeup water for their cooling systems. Table 2-2.

The use of any water, including reclaimed water, as makeup in recirculating cooling tower systems will result in the concentration of dissolved solids in the heat exchange system. This concentration may or may not cause serious corrosion of components. Three requirements should be considered to identify the cooling system corrosion potential: 1. Calculation of the concentrated cooling water quality – most often “worst” case but also “average expected” water quality

Florida and California Reclaimed Water Quality
Water Constituents Conductivity Calcium Hardness Total Alkalinity Chlorides Phosphate Ammonia Suspended Solids Orlando Tampa Los Angeles 2000 – 2700 260 – 450 140 – 280 250 – 350 300 – 400 4 – 20 10 – 45 San Francisco 800 – 1200 50 – 180 30 – 120 40 – 200 20 – 70 2 –8 2 – 10

1200 – 1800 600 – 1500 180 – 200 100 – 120 150 – 200 20 – 40 18 – 25 10 – 15 3–5 60 – 100 30 – 80 10 – 20 5 – 15 3–5



Identification of metal alloys in the process equipment that will contact cooling water– primarily heat exchanger/cooler/condenser tubing but also all other metals in the system, including lines, water box, tube sheet, and cooling tower Operating conditions (temperatures and water flow) of the cooling tower – primarily related to the heat exchanger tubing but also the other metals in the system


However, even when freshwater is used in cooling towers, chemicals added during the treatment process can contribute a considerable concentration of nutrients. It is also important to have a good biological control program in place before reclaimed water is used. Ammonia and organics are typical nutrients found in reclaimed water that can reduce or negate some commonly used biocides (particularly cationic charged polymers). Concerns The primary constituents for scale potential from reclaimed water are calcium, magnesium, sulfate, alkalinity, phosphate, silica, and fluoride. Combinations of these minerals that can produce scale in the concentrated cooling water generally include calcium phosphate (most common), silica (fairly common), calcium sulfate (fairly common), calcium carbonate (seldom found), calcium fluoride (seldom found), and magnesium silicate (seldom found). All constituents with the potential to form scale must be evaluated and controlled by chemical treatment and/or by adjusting the cycles of concentration. Reclaimed water quality must be evaluated, along with the scaling potential to establish the use of specific scale inhibitors. Guidelines for selection and use of scale inhibitors are available as are scale predictive tools.

Depending upon its level of treatment, the quality of reclaimed water can vary substantially. The amount of concentration in the cooling system will also vary substantially, depending on the cycles of concentration within the system. Certainly, any contamination of the cooling water through process in-leakage, atmospheric conditions, or treatment chemicals will impact the water quality. Biological Concerns

Biological concerns associated with the use of reclaimed water in cooling systems include:

Microbiological organisms that contribute to the potential for deposits and microbiologically induced corrosion (MIC) Nutrients that contribute to microbiological growth



Boiler Make-up Water

Microbiological organisms (bacteria, fungus, or algae) that contribute to deposits and corrosion are most often those adhering to surfaces and identified as “sessile” microorganisms. The deposits usually occur in low flow areas (2 feet per second [0.6 m/s] or less) but can stick to surfaces even at much greater flow rates (5 to 8 feet per second [1.5 to 2 m/s]). The deposits can create a variety of concerns and problems. Deposits can interfere with heat transfer and can cause corrosion directly due to acid or corrosive by-products. Indirectly, deposits may shield metal surfaces from water treatment corrosion inhibitors and establish under-deposit corrosion. Deposits can grow rapidly and plug heat exchangers, cooling tower film fill, or cooling tower water distribution nozzles/sprays. Reclaimed water generally has a very low level of microbiological organisms due to the treatment requirements prior to discharge. Chlorine levels of 2.0 mg/l (as free chlorine) will kill most sessile microorganisms that cause corrosion or deposits in cooling systems. Nutrients that contribute to microbiological growth are present in varying concentrations in reclaimed water.

The use of reclaimed water for boiler make-up water differs little from the use of conventional public water supply; both require extensive additional treatment. Quality requirements for boiler make-up water depend on the pressure at which the boiler is operated. Generally, the higher the pressure, the higher the quality of water required. Very high pressure (1500 psi [10,340 kPa] and above) boilers require make-up water of very high quality. In general, both potable water and reclaimed water used for boiler water make-up must be treated to reduce the hardness of the boiler feed water to close to zero. Removal or control of insoluble scales of calcium and magnesium, and control of silica and alumina, are required since these are the principal causes of scale buildup in boilers. Depending on the characteristics of the reclaimed water, lime treatment (including flocculation, sedimentation, and recarbonation) might be followed by multi-media filtration, carbon adsorption, and nitrogen removal. High-purity boiler feed water for high-pressure boilers might also require treatment by reverse osmosis or ion exchange. High alkalinity may contribute to foaming, resulting in deposits in the superheater, reheater, or tur-


bines. Bicarbonate alkalinity, under the influence of boiler heat, may lead to the release of carbon dioxide, which is a source of corrosion in steam-using equipment. The considerable treatment and relatively small amounts of makeup water required normally make boiler make-up water a poor candidate for reclaimed water. Since mid-2000, several refineries located in southern Los Angeles, California, have used reclaimed water as their primary source of boiler make-up water. Through the use of clarification, filtration, and reverse osmosis, high-quality boiler make-up water is produced that provides freshwater, chemical, and energy savings. The East Bay Municipal Utility District in California provides reclaimed water to the Chevron Refinery for use as boiler feed water. Table 2-3 shows the sampling requirements and expected water quality for the reclaimed water.

gallons of freshwater per ton (67 to 71 liters per kilogram) (NCASI, 2003). About a dozen pulp and paper mills use reclaimed water. Less than half of these mills use treated municipal wastewater. Tertiary treatment is generally required. The driver is usually an insufficient source of freshwater. SAPPI’s Enstra mill in South Africa has been using treated municipal wastewater since the early 1940s. In Lake Tahoe, California, the opportunities for using treated wastewater in pulping and papermaking arose with the construction of tertiary wastewater facilities (Dorica et al.,1998). Some of the reasons that mills choose not to use treated municipal wastewater include:
„ „

Concerns about pathogens Product quality requirements that specifically preclude its use Possibly prohibitive conveyance costs ing, and biofouling problems due to the high degree of internal recycling involved


Industrial Process Water

The suitability of reclaimed water for use in industrial processes depends on the particular use. For example, the electronics industry requires water of almost distilled quality for washing circuit boards and other electronic components. On the other hand, the tanning industry can use relatively low-quality water. Requirements for textiles, pulp and paper, and metal fabricating are intermediate. Thus, in investigating the feasibility of industrial reuse with reclaimed water, potential users must be contacted to determine the specific requirements for their process water. A full-scale demonstration plant, operated at Toppan Electronics, in San Diego, California, has shown that reclaimed water can be used for the production of circuit boards (Gagliardo et al., 2002). The reclaimed water used for the demonstration plant was pretreated with microfiltration. Table 2-4 presents industrial process water quality requirements for a variety of industries. Pulp and Paper Industry


„ Concerns about potentially increased corrosion, scal-

Table 2-5 shows the water quality requirements for several pulp and paper processes in New York City. Chemical Industry

The water quality requirements for the chemical industry vary greatly according to production requirements. Generally, waters in the neutral pH range (6.2 to 8.3) that are also moderately soft with low turbidity, suspended solids (SS), and silica are required; dissolved solids and chloride content are generally not critical (Water Pollution Control Federation, 1989). Textile Industry

The historical approach of the pulp and paper industry has been to internally recycle water to a very high degree. The pulp and paper industry has long recognized the potential benefits associated with water reuse. At the turn of the century, when the paper machine was being developed, water use was approximately 150,000 gallons per ton (625 liters per kilogram). By the 1950s, the water usage rate was down to 35,000 gallons per ton (145 liters per kilogram) (Wyvill et al., 1984). An industry survey conducted in 1966 showed the total water use for a bleached Kraft mill to be 179,000 gallons per ton (750 liters per kilogram) (Haynes, 1974). Modern mills approach a recycle ratio of 100 percent, using only 16,000 to 17,000

Waters used in textile manufacturing must be non-staining; hence, they must be low in turbidity, color, iron, and manganese. Hardness may cause curds to deposit on the textiles and may cause problems in some of the processes that use soap. Nitrates and nitrites may cause problems in dyeing. In 1997, a local carpet manufacturer in Irvine, California, retrofitted carpet-dyeing facilities to use reclaimed water year-round (IRWD, 2003). The new process is as effective as earlier methods and is saving up to 500,000 gallons of potable water per day (22 l/s).


Table 2-3.

North Richmond Water Reclamation Plant Sampling Requirements
Sample Type Parameter Frequency Target Value2 Max. 2 NTU, Min. 300 CT, 2.2 MPN/100 ml NA


Samples Required for Compliance with RWQCB Order 90-137 Chevron Tie-In Reclaimed Water Effluent Filter Influent, Filter Effluent, Chlorine Contact Basin Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Reclaimed Water Effluent Grab

Turbidity, Total Chlorine 1 2 Residual , Total Coliform Flow


24-hour composite


Samples Required for Compliance with EBMUD-Chevron Agreement; Chevron’s NPDES Permit Online Analyzers3 24-hour composite 24-hour composite pH, Turbidity, Free Chlorine Residual Orthophosphate (PO4) Calcium, Total Iron, Magnesium, Silica, TSS Ammonia (NH3-N), Chloride Continuous Daily 6.5-7.5, 2 NTU, <4.0 mg/l <1.4 mg/l 50 mg/l, 0.1 mg/l, 20 mg/l, 10 mg/l, <1.0 mg/l, <175 mg/l >90% Survival <50 mg/l, Report Only <1.0 mg/l Report Only4


96-hour flow through Rainbow trout acute bioassay Weekly 24-hour composite 24-hour composite 24-hour composite Grab Grab COD, TOC (Grab), Selenium, Weekly Surfactants Total Chromium, Hexavalent Cr, Ag, As, TOC, Cd, Monthly Cyanide, Cu, Hg, Pb, Ni, Zn – mg/� Total Phenolics, PAHs Oil and Grease, Total Sulfides Volatile Organics, Halogenated Volatile Organics TCDD Equivalents, Tributyltin, Halogenated Volatile Organics, Polychlorinated Biphenyls, Pesticides Quarterly Quarterly Twice/Year

Report Only4 Report Only4 Report Only4

Reclaimed Water Effluent



Report Only


NOTES: 1. Chlorine residual may vary based on CT calculation (contact time x residual = 300 CT); 90 minute minimum contact time. 2. Sample must be collected at reclaimed water metering station at pipeline tie-in to Chevron Refinery cooling towers; 90 minute chlorine contact time requirement. 3. Readouts for online analyzers are on graphic panel in Operations Center. 4. “Report Only” parameters are used for pass-through credit for reclaimed water constituents as provided for in Chevron’s National Pollutant Discharge Elimination System (NPDES) permit. Source: Yologe, 1996 18

Table 2-4.

Industrial Process Water Quality Requirements
Pulp & Paper Textiles Pulp & Paper Bleached 0.1 0.05 20 12 200 50 100 10 10 6-10 Chemical Petrochem & Coal 0.05 1.0 75 30 300 350 1,000 10 6-9 Sizing Suspension 0.01 0.3 0.05 25 100 5 5 Scouring, Bleach & Dye 0.1 0.01 25 100 5 5 Cement


Mechanical Piping 0.3 0.1 1,000 30 6-10 -

Chemical, Unbleached 1.0 0.5 20 12 200 50 100 10 30 6-10 -

Cu Fe Mn Ca Mg Cl HCO3 NO3 SO4 SiO2 Hardness Alkalinity TDS TSS Color pH CCE

0.1 0.1 68 19 500 128 5 100 50 250 125 1,000 5 20 6.2-8.3 -

2.5 0.5 250 250 35 400 600 500 6.5-8.5 -

*All values in mg/l except color and pH. Source: Water Pollution Control Federation, 1989.

Table 2-5.

Pulp and Paper Process Water Quality Requirements
Chemical, Unbleached 1 0.5 20 12 200 50 100 10 30 6 - 10 Pulp and Paper, Bleached 0.1 0.05 20 12 200 50 100 10 10 6 - 10

Parameter Iron Manganese Calcium Magnesium Chlorine Silicon Dioxide Hardness TSS Color pH


Mechanical Pulping 0.3 0.1 1,000 30 6 - 10

All values in mg/l except color and pH.

Source: Adamski et al., 2000


Petroleum and Coal

Figure 2-4.

Processes for the manufacture of petroleum and coal products can usually tolerate water of relatively low quality. Waters generally must be in the 6 to 9 pH range and have moderate SS of no greater than 10 mg/l.

Comparison of Agricultural Irrigation, Public/Domestic, and Total Freshwater Withdrawals


Agricultural Reuse

This section focuses on the following specific considerations for implementing a water reuse program for agricultural irrigation:
„ Agricultural irrigation demands „ Reclaimed water quality „

Other system considerations for approximately 48 percent of the total volume of reclaimed water used within the state (California State Water Resources Control Board, 2002). Figure 2-5 shows the percentages of the types of crops irrigated with reclaimed water in California. Agricultural reuse is often included as a component in water reuse programs for the following reasons:
„ Extremely high water demands for agricultural irriga-

Technical issues common to all reuse programs are discussed in Chapter 3, and the reader is referred to the following subsections for this information: 3.4 – Treatment Requirements, 3.5 – Seasonal Storage Requirements, 3.6 – Supplemental Facilities (conveyance and distribution, operational storage, and alternative disposal). Agricultural irrigation represents a significant percentage of the total demand for freshwater. As discussed in Chapter 3, agricultural irrigation is estimated to represent 40 percent of the total water demand nationwide (Solley et al., 1998). In western states with significant agricultural production, the percentage of freshwater used for irrigation is markedly greater. For example, Figure 24 illustrates the total daily freshwater withdrawals, public water supply, and agricultural irrigation usage for Montana, Colorado, Idaho, and California. These states are the top 4 consumers of water for agricultural irrigation, which accounts for more than 80 percent of their total water demand. The total cropland area in the U.S. and Puerto Rico is estimated to be approximately 431 million acres (174 million hectares), of which approximately 55 million acres (22 million hectares) are irrigated. Worldwide, it is estimated that irrigation water demands exceed all other categories of water use and make up 75 percent of the total water usage (Solley et al., 1998). A significant portion of existing water reuse systems supply reclaimed water for agricultural irrigation. In Florida, agricultural irrigation accounts for approximately 19 percent of the total volume of reclaimed water used within the state (Florida Department of Environmental Protection, 2002b). In California, agricultural irrigation accounts


Figure 2-5.

Agricultural Reuse Categories by Percent in California



Significant water conservation benefits associated with reuse in agriculture applications

„ Ability to integrate agricultural reuse with other reuse

face membranes, is a function of available soil moisture, season, and stage of growth. The rate of transpiration may be further impacted by soil structure and the salt concentration in the soil water. Primary factors affecting evaporation and transpiration are relative humidity, wind, and solar radiation. Practically every state in the U.S. and Canada now has access to weather information from the Internet. California has developed the California Irrigation Management Information System (CIMIS), which allows growers to obtain daily reference evapotranspiration information. Data are made available for numerous locations within the state according to regions of similar climatic conditions. State publications provide coefficients for converting these reference data for use on specific crops, location, and stages of growth. This allows users to refine irrigation scheduling and conserve water. Other examples of weather networks are the Michigan State University Agricultural Weather Station, the Florida Automated Weather Network, and the Agri-Food Canada Lethbridge Research Centre Weather Station Network. Numerous equations and methods have been developed to define the evapotranspiration term. The Thornthwaite and Blaney-Criddle methods of estimating evapotranspiration are 2 of the most cited methods. The Blaney-Criddle equation uses percent of daylight hours per month and average monthly temperature. The Thornthwaite method relies on mean monthly temperature and daytime hours. In addition to specific empirical equations, it is quite common to encounter modifications to empirical equations for use under specific regional conditions. In selecting an empirical method of estimating evapotranspiration, the potential user is encouraged to solicit input from local agencies familiar with this subject. Effective Precipitation, Percolation, and Surface Water Runoff Losses

Due to saltwater intrusion to its agricultural wells, the City of Watsonville, California, is looking to develop 4,000 acre-feet per year (2,480 gpm) of reuse for the irrigation of strawberries, artichokes, and potentially certified organic crops (Raines et al., 2002). Reclaimed water will make up 25 percent of the estimated new water required for irrigation.


Estimating Agricultural Irrigation Demands

Because crop water requirements vary with climatic conditions, the need for supplemental irrigation will vary from month to month throughout the year. This seasonal variation is a function of rainfall, temperature, crop type, stage of plant growth, and other factors, depending on the method of irrigation being used. The supplier of reclaimed water must be able to quantify these seasonal demands, as well as any fluctuation in the reclaimed water supply, to assure that the demand for irrigation water can be met. Unfortunately, many agricultural users are unable to provide sufficient detail about irrigation demands for design purposes. This is because the user’s seasonal or annual water use is seldom measured and recorded, even on land surfaces where water has been used for irrigation for a number of years. However, expert guidance is usually available through state colleges and universities and the local soil conservation service office. To assess the feasibility of reuse, the reclaimed water supplier must be able to reasonably estimate irrigation demands and reclaimed water supplies. To make this assessment in the absence of actual water use data, evapotranspiration, percolation and runoff losses, and net irrigation must be estimated, often through the use of predictive equations. Evapotranspiration

Evapotranspiration is defined as water either evaporated from the soil surface or actively transpired from the crop. While the concept of evapotranspiration is easily described, quantifying the term mathematically is difficult. Evaporation from the soil surface is a function of the soil moisture content at or near the surface. As the top layer of soil dries, evaporation decreases. Transpiration, the water vapor released through the plants’ sur-

The approach for the beneficial reuse of reclaimed water will, in most cases, vary significantly from land application. In the case of beneficial reuse, the reclaimed water is a resource to be used judiciously. The prudent allocation of this resource becomes even more critical in locations where reclaimed water is assigned a dollar value, thereby becoming a commodity. Where there is a cost associated with using reclaimed water, the recipient of reclaimed water will seek to balance the cost of supplemental irrigation against the expected increase in crop yields to derive the maximum economic benefit. Thus, percolation losses will be minimized because they represent the loss of water available to the crop and wash fertilizers out of the root zone. An exception to this occurs when the reclaimed water has a high salt concen-


tration and excess application is required to prevent the accumulation of salts in the root zone. Irrigation demand is the amount of water required to meet the needs of the crop and also overcome system losses. System losses will consist of percolation, surface water runoff, and transmission and distribution losses. In addition to the above losses, the application of water to crops will include evaporative losses or losses due to wind drift. These losses may be difficult to quantify individually and are often estimated as single system efficiency. The actual efficiency of a given system will be site specific and vary widely depending on management practices followed. Irrigation efficiencies typically range from 40 to 98 percent (Vickers, 2001). A general range of efficiencies by type of irrigation system is shown in Table 2-6. Since there are no hard and fast rules for selecting the most appropriate method for projecting irrigation demands and establishing parameters for system reliability, it may be prudent to undertake several of the techniques and to verify calculated values with available records. In the interest of developing the most useful models, local irrigation specialists should be consulted.


Reclaimed Water Quality

The chemical constituents in reclaimed water of concern for agricultural irrigation are salinity, sodium, trace elements, excessive chlorine residual, and nutrients. Sensitivity is generally a function of a given plant’s tolerance to constituents encountered in the root zone or deposited on the foliage. Reclaimed water tends to have higher concentrations of these constituents than the groundwater or surface water sources from which the water supply is drawn. The types and concentrations of constituents in reclaimed wastewater depend upon the municipal water supply, the influent waste streams (i.e., domestic and industrial contributions), amount and composition of infiltration in the wastewater collection system, the wastewater treatment processes, and type of storage facilities. Conditions that can have an adverse impact on reclaimed water quality may include:
„ Elevated TDS levels „ Industrial discharges of potentially toxic compounds

into the municipal sewer system

Saltwater (chlorides) infiltration into the sewer system in coastal areas

Table 2-6.

Efficiencies for Different Irrigation Systems
Potential On-Farm Efficiency1 (Percent) 75-85 55-70 40-50 80-90 70-85 60-80 65-80 60-65 60-65 80-95

Irrigation System Gravity (Surface) Improved gravity2 Furrow Flood Sprinklers Low energy precision application (LEPA) Center pivot3 Sideroll Solid set Hand-move Big gun Microirrigation Drip

Efficiencies shown assume appropriate irrigation system selection, correct irrigation design, and proper management. 2 Includes tailwater recovery, precision land leveling, and surge flow systems. 3 Includes high- and low-pressure center pivot. Source: Vickers, 2001. 22

For example, reclaimed water is used mostly for ridge and furrow irrigation at the High Hat Ranch in Sarasota, Florida, although a portion of the reclaimed water is used for citrus irrigation via microjet irrigation. To achieve successful operation of the microjet irrigation system, filters were installed to provide additional solids removal treatment to the reclaimed water used for citrus irrigation. Salinity

Salinity reduces the water uptake in plants by lowering the osmotic potential of the soil. This, in turn, causes the plant to use a large portion of its available energy to adjust the salt concentration within its tissue in order to obtain adequate water. This results in less energy available for plants to grow. The problem is more severe in hot and dry climatic conditions because of increased water demands by plants and is even more severe when irrigation is inadequate. One location where subsurface drainage is being evaluated is in California’s San Joaquin Valley. The drainage management process is called “integrated on-farm drainage management” and involves reusing the drainage water and using it to irrigate more salt-tolerant crops. The final discharge water goes into solar evaporators that collect the dry agricultural salt. Further complications of salinity problems can occur in geographic locations where the water table is high. A high water table can cause a possible upward flow of high salinity water into the root zone. Subsurface drainage offers a viable solution in these locations. Older clay tiles are often replaced with fabric-covered plastic pipe to prevent clogging. This subsurface drainage technique is one salinity-controlling process that requires significant changes in irrigation management. There are other techniques that require relatively minor changes including more frequent irrigation schedules, selection of more salttolerant crops, seed placement, additional leaching, bed forming, and pre-plant irrigation. Sodium

Salinity is the single most important parameter in determining the suitability of the water to be used for irrigation. Salinity is determined by measuring the electrical conductivity (EC) and/or the total dissolved solids (TDS) in the water. Estimates indicate that 23 percent of irrigated farmland has been damaged by salt (Postel, 1999). The salinity tolerance of plants varies widely. Crops must be chosen carefully to ensure that they can tolerate the salinity of the irrigation water, and even then the soil must be properly drained and adequately leached to prevent salt build-up. Leaching is the deliberate over-application of irrigation water in excess of crop needs to establish a downward movement of water and salt away from the root zone. The extent of salt accumulation in the soil depends on the concentration of salts in the irrigation water and the rate at which salts are removed by leaching. Salt accumulation can be especially detrimental during germination and when plants are young (seedlings). At this stage, damage can occur even with relatively low salt concentrations. Concerns with salinity relate to possible impacts to the following: the soil’s osmotic potential, specific ion toxicity, and degradation of soil physical conditions. These conditions may result in reduced plant growth rates, reduced yields, and, in severe cases, total crop failure. The concentration of specific ions may cause one or more of these trace elements to accumulate in the soil and in the plant. Long-term build-up may result in animal and human health hazards or phytotoxicity in plants. When irrigating with municipal reclaimed water, the ions of most concern are sodium, chloride, and boron. Household detergents are usually the source of boron and water softeners contribute sodium and chloride. Plants vary greatly in their sensitivity to specific ion toxicity. Toxicity is particularly detrimental when crops are irrigated with overhead sprinklers during periods of high temperature and low humidity. Highly saline water applied to the leaves results in direct absorption of sodium and/or chloride and can cause leaf injury.

The potential influence sodium may have on soil properties is indicated by the sodium-adsorption-ratio (SAR), which is based on the effect of exchangeable sodium on the physical condition of the soil. SAR expresses the concentration of sodium in water relative to calcium and magnesium. Excessive sodium in irrigation water (when sodium exceeds calcium by more than a 3:1 ratio) contributes to soil dispersion and structural breakdown, where the finer soil particles fill many of the smaller pore spaces, sealing the surface and greatly reducing water infiltration rates (AWWA, 1997). For reclaimed water, it is recommended that the calcium ion concentration in the SAR equation be adjusted for alkalinity to include a more correct estimate of calcium in the soil water following irrigation, specifically adj RNa. Note that the calculated adj RNa is to be substituted for the SAR value. Sodium salts influence the exchangeable cation composition of the soil, which lowers the permeability and affects the tilth of the soil. This usually occurs within the first few inches of the soil and is related to high sodium


or very low calcium content in the soil or irrigation water. Sodium hazard does not impair the uptake of water by plants but does impair the infiltration of water into the soil. The growth of plants is thus affected by an unavailability of soil water (Tanji, 1990). Calcium and magnesium act as stabilizing ions in contrast to the destabilizing ion, sodium, in regard to the soil structure. They offset the phenomena related to the distance of charge neutralization for soil particles caused by excess sodium. Sometimes the irrigation water may dissolve sufficient calcium from calcareous soils to decrease the sodium hazard appreciably. Leaching and dissolving the calcium from the soil is of little concern when irrigating with reclaimed water because it is usually high enough in salt and calcium. Reclaimed water, however, may be high in sodium relative to calcium and may cause soil permeability problems if not properly managed. Trace Elements

in nutrient solutions or sand cultures to which the pollutant has been added. This does not mean that if the suggested limit is exceeded that phytotoxicity will occur. Most of the elements are readily fixed or tied up in soil and accumulate with time. Repeated applications in excess of suggested levels might induce phytotoxicity. The criteria for short-term use (up to 20 years) are recommended for fine-textured neutral and alkaline soils with high capacities to remove the different pollutant elements. Chlorine Residual

The elements of greatest concern at elevated levels are cadmium, copper, molybdenum, nickel, and zinc. Nickel and zinc have visible adverse effects in plants at lower concentrations than the levels harmful to animals and humans. Zinc and nickel toxicity is reduced as pH increases. Cadmium, copper, and molybdenum, however, can be harmful to animals at concentrations too low to impact plants. Copper is not toxic to monogastric animals, but may be toxic to ruminants. However, their tolerance to copper increases as available molybdenum increases. Molybdenum can also be toxic when available in the absence of copper. Cadmium is of particular concern as it can accumulate in the food chain. It does not adversely affect ruminants due to the small amounts they ingest. Most milk and beef products are also unaffected by livestock ingestion of cadmium because the cadmium is stored in the liver and kidneys of the animal, rather than the fat or muscle tissues. In addition, it was found that the input of heavy metals from commercial chemical fertilizer impurities was far greater than that contributed by the reclaimed water (Engineering Science, 1987). Table 2-7 shows EPA’s recommended limits for constituents in irrigation water. The recommended maximum concentrations for “longterm continuous use on all soils” are set conservatively to include sandy soils that have low capacity to leach (and so to sequester or remove) the element in question. These maxima are below the concentrations that produce toxicity when the most sensitive plants are grown

Free chlorine residual at concentrations less than 1 mg/ l usually poses no problem to plants. However, some sensitive crops may be damaged at levels as low as 0.05 mg/l. Some woody crops, however, may accumulate chlorine in the tissue to toxic levels. Excessive chlorine has a similar leaf-burning effect as sodium and chloride when sprayed directly on foliage. Chlorine at concentrations greater than 5 mg/l causes severe damage to most plants. Nutrients

The nutrients most important to a crop’s needs are nitrogen, phosphorus, potassium, zinc, boron, and sulfur. Reclaimed water usually contains enough of these nutrients to supply a large portion of a crop’s needs. The most beneficial nutrient is nitrogen. Both the concentration and form of nitrogen need to be considered in irrigation water. While excessive amounts of nitrogen stimulate vegetative growth in most crops, it may also delay maturity and reduce crop quality and quantity. The nitrogen in reclaimed water may not be present in concentrations great enough to produce satisfactory crop yields, and some supplemental fertilizer may be necessary. In addition, excessive nitrate in forages can cause an imbalance of nitrogen, potassium, and magnesium in grazing animals. This is a concern if the forage is used as a primary feed source for livestock; however, such high concentrations are usually not expected with municipal reclaimed water. Soils in the western U.S. may contain enough potassium, while many sandy soils of the southern U.S. do not. In either case, the addition of potassium with reclaimed water has little effect on crops. Phosphorus contained in reclaimed water is usually at too low a level to meet a crop’s needs. Yet, over time, it can build up in the soil and reduce the need for phosphorus supplementation. Excessive phosphorus levels do not appear to pose any problems to crops, but can be a problem in runoff to surface waters.


Table 2-7.

Recommended Limits for Constituents in Reclaimed Water for Irrigation
Long-Term Use (mg/l) 5.0 0.10 0.10 Short-Term Use (mg/l) 20 2.0 0.5 Remarks Can cause nonproductiveness in acid soils, but soils at pH 5.5 to 8.0 will precipitate the ion and eliminate toxicity. Toxicity to plants varies widely, ranging from 12 mg/L for Sudan grass to less than 0.05 mg/L for rice. Toxicity to plants varies widely, ranging from 5 mg/L for kale to 0.5 mg/L for bush beans. Essential to plant growth, with optimum yields for many obtained at a fewtenths mg/L in nutrient solutions. Toxic to many sensitive plants (e.g., citrus) at 1 mg/L. Usually sufficient quantities in reclaimed water to correct soil deficiencies. Most grasses are relatively tolerant at 2.0 to 10 mg/L. Toxic to beans, beets, and turnips at concentrations as low as 0.1 mg/L in nutrient solution. Conservative limits recommended. Not generally recognized as an essential growth element. Conservative limits recommended due to lack of knowledge on toxicity to plants. Toxic to tomato plants at 0.1 mg/L in nutrient solution. Tends to be inactivated by neutral and alkaline soils. Toxic to a number of plants at 0.1 to 1.0 mg/L in nutrient solution. Inactivated by neutral and alkaline soils. Not toxic to plants in aerated soils, but can contribute to soil acidification and loss of essential phosphorus and molybdenum. Can inhibit plant cell growth at very high concentrations. Tolerated by most crops at concentrations up to 5 mg/L; mobile in soil. Toxic to citrus at low doses - recommended limit is 0.075 mg/L. Toxic to a number of crops at a few-tenths to a few mg/L in acidic soils. Nontoxic to plants at normal concentrations in soil and water. Can be toxic to livestock if forage is grown in soils with high levels of available molybdenum. Toxic to a number of plants at 0.5 to 1.0 mg/L; reduced toxicity at neutral or alkaline pH. Toxic to plants at low concentrations and to livestock if forage is grown in soils with low levels of selenium. Effectively excluded by plants; specific tolerance levels unknown Toxic to many plants at relatively low concentrations. Toxic to many plants at widely varying concentrations; reduced toxicity at increased pH (6 or above) and in fine-textured or organic soils. Remarks Most effects of pH on plant growth are indirect (e.g., pH effects on heavy metals’ toxicity described above). Below 500 mg/L, no detrimental effects are usually noticed. Between 500 and 1,000 mg/L, TDS in irrigation water can affect sensitive plants. At 1,000 to 2,000 mg/L, TDS levels can affect many crops and careful management practices should be followed. Above 2,000 mg/L, water can be used regularly only for tolerant plants on permeable soils. Concentrations greater than 5 mg/l causes severe damage to most plants. Some sensitive plants may be damaged at levels as low as 0.05 mg/l.

Constituent Aluminum Arsenic Beryllium




Cadmium Chromium Cobalt Copper Fluoride Iron Lead Lithium Manganese Molybdenum Nickel Selenium Tin, Tungsten, & Titanium Vanadium Zinc Constituent pH

0.01 0.1 0.05 0.2 1.0 5.0 5.0 2.5 0.2 0.01 0.2 0.02 0.1 2.0

0.05 1.0 5.0 5.0 15.0 20.0 10.0 2.5 10.0 0.05 2.0 0.02 1.0 10.0

Recommended Limit 6.0


500 - 2,000 mg/l

Free Chlorine Residual

<1 mg/l

Source: Adapted from Rowe and Abdel-Magid, 1995.

Numerous site-specific studies have been conducted regarding the potential water quality concerns associated with reuse irrigation. The overall conclusions from the Monterey (California) Wastewater Reclamation Study for Agriculture (Jaques, 1997) are as follows:


Irrigation with filtered effluent (FE) or Title-22 effluent (T-22) appears to be as safe as well water. Few statistically significant differences were found in soil or plant parameters, and none were found to



be attributable to different types of water. None of the differences had important implications for public health.
„ Yields of annual crops were often significantly higher

with reclaimed water.

No viruses were detected in any of the reclaimed waters, although viruses were often detected in the secondary effluent prior to the reclamation process. the FE process in removing viruses when the influent was seeded at high levels of virus concentration. However, both processes demonstrated the ability to remove more than 5 logs of viruses during the seeding experiments. (Jaques, 1997)

Reliability in quality involves providing the appropriate treatment for the intended use, with special consideration of crop sensitivities and potential toxicity effects of reclaimed water constituents (See Sections 3.4 and 2.3.2). Reliability in quantity involves balancing irrigation supply with demand. This is largely accomplished by providing sufficient operational and seasonal storage facilities (See Sections 3.5 and 3.5.2.) It is also necessary to ensure that the irrigation system itself can reliably accept the intended supply to minimize the need for discharge or alternate disposal. Site Use Control

„ The T-22 process was somewhat more efficient than

This and other investigations suggest that reclaimed water is suitable for most agricultural irrigation needs.


Other System Considerations

In addition to irrigation supply and demand and reclaimed water quality requirements, there are other considerations specific to agricultural water reuse that must be addressed. Both the user and supplier of reclaimed water may have to consider modifications in current practice that may be required to use reclaimed water for agricultural irrigation. The extent to which current irrigation practices must be modified to make beneficial use of reclaimed water will vary on a case-by-case basis. Important considerations include:
„ „

Many states require a buffer zone around areas irrigated with reclaimed water. The size of this buffer zone is often associated with the level of treatment the reclaimed water has received and the means of application. Additional controls may include restrictions on the times that irrigation can take place and restrictions on the access to the irrigated site. Such use area controls may require modification to existing farm practices and limit the use of reclaimed water to areas where required buffer zones cannot be provided. See Chapter 4 for a discussion of the different buffer zones and use controls specified in state regulations. Signs specifying that reclaimed water is being used may be required to prevent accidental contact or ingestion. Monitoring Requirements

System reliability Site use control

Monitoring requirements for reclaimed water use in agriculture differ by state (See Chapter 4). In most cases, the supplier will be required to sample the reclaimed water quality at specific intervals for specific constituents. Sampling may be required at the water reclamation plant and, in some cases, in the distribution system. Groundwater monitoring is often required at the agricultural site, with the extent depending on the reclaimed water quality and the hydrogeology of the site. Groundwater monitoring programs may be as simple as a series of surficial wells to a complex arrangement of wells sampling at various depths. Monitoring must be considered in estimating the capital and operating costs of the reuse system, and a complete understanding of monitoring requirements is needed as part of any cost/benefit analysis. Runoff Controls

„ Monitoring requirements „

Runoff controls

„ Marketing incentives „ Irrigation equipment

System Reliability

System reliability involves 2 basic issues. First, as in any reuse project that is implemented to reduce or eliminate surface water discharge, the treatment and distribution facilities must operate reliably to meet permit conditions. Second, the supply of reclaimed water to the agricultural user must be reliable in quality and quantity for successful use in a farming operation.

Some irrigation practices, such as flood irrigation, result in a discharge of irrigation water from the site (tail water). Regulatory restrictions of this discharge may be few or none when using surface water or groundwater sources;


however, when reclaimed water is used, runoff controls may be required to prevent discharge or a National Pollutant Discharge Elimination System (NPDES) permit may be required for a surface water discharge. Marketing Incentives

In many cases, an existing agricultural site will have an established source of irrigation water, which has been developed by the user at some expense (e.g., engineering, permitting, and construction). In some instances, the user may be reluctant to abandon these facilities for the opportunity to use reclaimed water. Reclaimed water use must then be economically competitive with existing irrigation practices or must provide some other benefits. For example, in arid climates or drought conditions where potable irrigation is restricted for water conservation purposes, reclaimed water could be offered as a dependable source of irrigation. Reclaimed water may also be of better quality than that water currently available to the farmer, and the nutrients may provide some fertilizer benefit. In some instances, the supplier of reclaimed water may find it cost effective to subsidize reclaimed water rates to agricultural users if reuse is allowing the supplier to avoid higher treatment costs associated with alternative means of disposal. Irrigation Equipment

plete or partial clogging of emitters. Close, regular inspections of emitters are required to detect emitter clogging. In-line filters of an 80 to 200 mesh are typically used to minimize clogging. In addition to clogging, biological growth within the transmission lines and at the emitter discharge may be increased by nutrients in the reclaimed water. Due to low volume application rates with micro-irrigation, salts may accumulate at the wetted perimeter of the plants and then be released at toxic levels to the crop when leached via rainfall.


Environmental and Recreational Reuse

Environmental reuse includes wetland enhancement and restoration, creation of wetlands to serve as wildlife habitat and refuges, and stream augmentation. Uses of reclaimed water for recreational purposes range from landscape impoundments, water hazards on golf courses, to full-scale development of water-based recreational impoundments, incidental contact (fishing and boating) and full body contact (swimming and wading). As with any form of reuse, the development of recreational and environmental water reuse projects will be a function of a water demand coupled with a cost-effective source of suitable quality reclaimed water. As discussed in Chapter 4, many states have regulations that specifically address recreational and environmental uses of reclaimed water. For example, California’s recommended treatment train for each type of recreational water reuse is linked to the degree of body contact in that use (that is, to what degree swimming and wading are likely). Secondary treatment and disinfection to 2.2 total coliforms/100 ml average is required for recreational water bodies where fishing, boating, and other non-body contact activities are permitted. For nonrestricted recreational use that includes wading and swimming, treatment of secondary effluent is to be followed by coagulation, filtration, and disinfection to achieve 2.2 total coliforms/100 ml and a maximum of 23 total coliforms/100 ml in any one sample taken during a 30-day period. In California, approximately 10 percent (47.6 mgd) (2080 l/s) of the total reclaimed water use within the state was associated with recreational and environmental reuse in 2000 (California State Water Resources Control Board, 2002). In Florida, approximately 6 percent (35 mgd or 1530 l/s) of the reclaimed water currently produced is being used for environmental enhancements, all for wetland enhancement and restoration (Florida Department of Environmental Protection, 2002). In Florida, from 1986 to 2001, there was a 53 percent increase (18.5 mgd to 35 mgd or 810 l/s to 1530 l/s) in the reuse flow used for

By and large, few changes in equipment are required to use reclaimed water for agricultural irrigation. However, some irrigation systems do require special considerations. Surface irrigation systems (ridge and furrow, graded borders) normally result in the discharge of a portion of the irrigation water from the site. Where reclaimed water discharge is not permitted, some method of tail water return or pump-back may be required. In sprinkler systems, dissolved salts and particulate matter may cause clogging, depending on the concentration of these constituents as well as the nozzle size. Because water droplets or aerosols from sprinkler systems are subject to wind drift, the use of reclaimed water may necessitate the establishment of buffer zones around the irrigated area. In some types of systems (i.e., center pivots), the sprinkler nozzles may be dropped closer to the ground to reduce aerosol drift and thus minimize the buffer requirements. In addition, some regulatory agencies restrict the use of sprinkler irrigation for crops to be eaten raw, because it results in the direct contact of reclaimed water with the fruit. When reclaimed water is used in a micro-irrigation system, a good filtration system is required to prevent com-


environmental enhancements (wetland enhancement and restoration). Two examples of large-scale environmental and recreational reuse projects are the City of West Palm Beach, Florida, wetlands-based water reclamation project (see case study 2.7.17) and the Eastern Municipal Water District multipurpose constructed wetlands in Riverside County, California. The remainder of this section provides an overview of the following environmental and recreational uses:
„ Natural and man-made wetlands „ Recreational and aesthetic impoundments „ Stream augmentation

For wetlands that have been altered hydrologically, application of reclaimed water serves to restore and enhance the wetlands. New wetlands can be created through application of reclaimed water, resulting in a net gain in wetland acreage and functions. In addition, man-made and restored wetlands can be designed and managed to maximize habitat diversity within the landscape. The application of reclaimed water to wetlands provides compatible uses. Wetlands are often able to enhance the water quality of the reclaimed water without creating undesirable impacts to the wetlands system. This, in turn, enhances downstream natural water systems and provides aquifer recharge. A great deal of research has been performed documenting the ability of wetlands, both natural and constructed, to provide consistent and reliable water quality improvement. With proper execution of design and construction elements, constructed wetlands exhibit characteristics that are similar to natural wetlands, in that they support similar vegetation and microbes to assimilate pollutants. In addition, constructed wetlands provide wildlife habitat and environmental benefits that are similar to natural wetlands. Constructed wetlands are effective in the treatment of BOD, TSS, nitrogen, phosphorus, pathogens, metals, sulfates, organics, and other toxic substances. Water quality enhancement is provided by transformation and/or storage of specific constituents within the wetland. The maximum contact of reclaimed water within the wetland will ensure maximum treatment assimilation and storage. This is due to the nature of these processes. If optimum conditions are maintained, nitrogen and BOD assimilation in wetlands will occur indefinitely, as they are primarily controlled by microbial processes and generate gaseous end products. In contrast, phosphorus assimilation in wetlands is finite and is related to the adsorption capacity of the soil and long-term storage within the system. The wetland can provide additional water quality enhancement (polishing) to the reclaimed water product. In most reclaimed water wetland projects, the primary intent is to provide additional treatment of effluent prior to discharge from the wetland. However, this focus does not negate the need for design considerations that will maximize wildlife habitats, and thereby provide important ancillary benefits. For constructed wetlands, appropriate plant species should be selected based on the type of wetland to be constructed as well as the habitat goals. Treatment performance information is available regarding certain wetland species as well as recommendations regarding species selection (Cronk and Fennessy, 2001).

The objectives of these reuse projects are typically to create an environment in which wildlife can thrive and/ or develop an area of enhanced recreational or aesthetic value to the community through the use of reclaimed water.


Natural and Man-made Wetlands

Over the past 200 years, approximately 50 percent of the wetlands in the continental United States have been destroyed for such diverse uses as agriculture, mining, forestry, and urbanization. Wetlands provide many worthwhile functions, including flood attenuation, wildlife and waterfowl habitat, productivity to support food chains, aquifer recharge, and water quality enhancement. In addition, the maintenance of wetlands in the landscape mosaic is important for the regional hydrologic balance. Wetlands naturally provide water conservation by regulating the rate of evapotranspiration and, in some cases, by providing aquifer recharge. The deliberate application of reclaimed water to wetlands can provide a beneficial use, and therefore reuse, by fulfilling any of the following objectives: 1. 2. To create, restore, and/or enhance wetlands systems To provide additional treatment of reclaimed water prior to discharge to a receiving water body To provide a wet weather disposal alternative for a water reuse system (See Section 3.6.4.)



Wetlands do not provide treatment of total suspended solids. In addition, a salinity evaluation may be necessary because effluent with a high salt content may cause impacts to wetland vegetation. In some cases, salt tolerant vegetation may be appropriate. Design considerations will need to balance the hydraulic and constituent loadings with impacts to the wetland. Impacts to groundwater quality should also be evaluated. The benefits of a wetland treatment system include:

downstream surface waters. A wetlands application system was selected because the wetlands: (1) serve as nutrient sinks and buffer zones, (2) have aesthetic and environmental benefits, and (3) can provide cost-effective treatment through natural systems. The Arcata wetlands system was also designed to function as a wildlife habitat. The Arcata wetlands system, consisting of three 10-acre (4-hectare) marshes, has attracted more than 200 species of birds, provided a fish hatchery for salmon, and contributed directly to the development of the Arcata Marsh and Wildlife Sanctuary (Gearheart, 1988). Due to a 20-mgd (877-L/s) expansion of the City of Orlando, Florida, Iron Bridge Regional Water Pollution Control Facility in 1981, a wetland system was created to handle the additional flow. Since 1981, reclaimed water from the Iron Bridge plant has been pumped 16 miles (20 kilometers) to a wetland that was created by berming approximately 1,200 acres (480 hectares) of improved pasture. The system is further divided into smaller cells for flow and depth management. The wetland consists of 3 major vegetative areas. The first area, approximately 410 acres (166 hectares), is a deep marsh consisting primarily of cattails and bulrush with nutrient removal as the primary function. The second area consists of 380 acres (154 hectares) of a mixed marsh composed of over 60 submergent and emergent herbaceous species used for nutrient removal and wildlife habitat. The final area, 400 acres (162 hectares) of hardwood swamp, consists of a variety of tree species providing nutrient removal and wildlife habitat. The reclaimed water then flows through approximately 600 acres (240 hectares) of natural wetland prior to discharge to the St. Johns River (Jackson, 1989). EPA (1999a) indicated that little effort had been made to collect or organize information concerning the habitat functions of treatment wetlands. Therefore, the Treatment Wetland Habitat and Wildlife Use Assessment document (U.S. EPA, 1999a) was prepared. The document was the first comprehensive effort to assemble wide-ranging information concerning the habitat and wildlife use data from surface flow treatment wetlands. The data have been gathered into an electronic format built upon the previous existing North American Treatment Wetland Database funded by the EPA. The report indicates that both natural and constructed treatment wetlands have substantial plant communities and wildlife populations. There are potentially harmful substances in the water, sediments, and biological tissues of treatment wetlands. However, contaminant concentration levels are generally below published action levels. There is apparently no documentation indicating that harm has occurred in any wetland intentionally designed to improve water quality.

Improve water quality through the use of natural systems Protect downstream receiving waters Provide wetland creation, restoration, or enhancement Provide wildlife and waterfowl habitat Offer relatively low operating and maintenance costs A reasonable development cost Maintain “green space” Attenuate peak flows One component of a “treatment train”; can be used in areas with high water table and/or low permeable soils Aesthetic and educational opportunities

„ „

„ „

„ „ „ „


Potential limitations of a wetland treatment systems include:
„ Significant land area requirements „ „

May have limited application in urban settings Potential for short-circuiting, which will lead to poor performance

„ Potential for nuisance vegetation and algae „

May need to be lined to maintain wetland hydroperiod

A number of cities have developed wetlands enhancement systems to provide wildlife habitats as well as treatment. In Arcata, California, one of the main goals of a city wetland project was to enhance the beneficial use of 29

The Yelm, Washington, project in Cochrane Memorial Park, is an aesthetically pleasing 8-acre (3-hectare) city park featuring constructed surface and submerged wetlands designed to polish the reclaimed water prior to recharging groundwater. In the center of the park, a fish pond uses the water to raise and maintain rainbow trout for catch and release (City of Yelm, 2003). A number of states including Florida, South Dakota, and Washington, provide regulations to specifically address the use of reclaimed water in wetlands systems. Where specific regulations are absent, wetlands have been constructed on a case-by-case basis. In addition to state requirements, natural wetlands, which are considered waters of the U.S., are protected under EPA’s NPDES Permit and Water Quality Standards programs. The quality of reclaimed water entering natural wetlands is regulated by federal, state and local agencies and must be treated to at least secondary treatment levels or greater to meet water quality standards. Constructed wetlands, on the other hand, which are built and operated for the purpose of treatment only, are not considered waters of the U.S. Wetland treatment technology, using free water surface wetlands, has been under development, with varying success, for nearly 30 years in the U.S. (U.S. EPA, 1999b). Several key documents that summarize the available information and should be used to assist in the design of wetland treatment systems are: Treatment Wetlands (Kadlec and Kngith, 1996), Free Water Surface Wetlands for Wastewater Treatment (U.S. EPA, 1999b), Constructed Wetlands for Pollution Control: Process, Performance, Design and Operation (IWA, 2000), and the Water Environment Federation Manual of Practice FD-16 Second Edition. Natural Systems for Wastewater Treatment, Chapter 9; Wetland Systems, (WEF, 2001).

ing in odors, an unsightly appearance, and eutrophic conditions. Reclaimed water impoundments can be easily incorporated into urban developments. For example, landscaping plans for golf courses and residential developments commonly integrate water traps or ponds. These same water bodies may also serve as storage facilities for irrigation water within the site. In Lubbock, Texas, approximately 4 mgd (175 l/s) of reclaimed water is used for recreational lakes in the Yellowhouse Canyon Lakes Park (Water Pollution Control Federation, 1989). The canyon, which was formerly used as a dump, was restored through the use of reclaimed water to provide water-oriented recreational activities. Four lakes, which include man-made waterfalls, are used for fishing, boating, and water skiing; however, swimming is restricted. Lakeside Lake is a 14-acre (6-hectare) urban impoundment in Tucson, Arizona. The lake was constructed in the 1970s in the Atterbury Wash to provide fishing, boating, and other recreational opportunities. The lake is lined with soil/cement layers and has a concrete shelf extending 6 feet (2 meters) from the shore around the perimeter. A berm crosses the lake from east to west, creating a north and south bay. The Arizona Game and Fish Department (AGFD) stock the lake with channel catfish, rainbow trout, bluegill, redear and hybrid sunfish, crappie, and large mouth bass on a seasonal basis. The lake was initially supplied by groundwater and surface runoff but began receiving reclaimed water from the Roger Road Treatment Plant in 1990 (up to 45,000 gpd) (170 m3/d). A mechanical diffuser was installed on the lake bottom in 1992 to improve dissolved oxygen concentrations (PBS&J, 1992).


Recreational and Aesthetic Impoundments


Stream Augmentation

For the purposes of this discussion, an impoundment is defined as a man-made water body. The use of reclaimed water to augment natural water bodies is discussed in Section 3.4.3. Impoundments may serve a variety of functions from aesthetic, non-contact uses, to boating and fishing, as well as swimming. As with other uses of reclaimed water, the required level of treatment will vary with the intended use of the water. As the potential for human contact increases, the required treatment levels increase. The appearance of the reclaimed water must also be considered when used for impoundments, and treatment for nutrient removal may be required as a means of controlling algae. Without nutrient control, there is a high potential for algae blooms, result-

Stream augmentation is differentiated from a surface water discharge in that augmentation seeks to accomplish a beneficial end, whereas discharge is primarily for disposal. Stream augmentation may be desirable to maintain stream flows and to enhance the aquatic and wildlife habitat as well as to maintain the aesthetic value of the water courses. This may be necessary in locations where a significant volume of water is drawn for potable or other uses, largely reducing the downstream volume of water in the river. As with impoundments, water quality requirements for stream augmentation will be based on the designated use of the stream as well as the aim to maintain an acceptable appearance. In addition, there may be an em-


phasis on creating a product that can sustain aquatic life. The San Antonio Water System in Texas releases its high quality (Type 1) reclaimed water to the San Antonio River. Reclaimed water is used instead of pumped groundwater to sustain the river flow through a city park, zoo, and downtown river walk. A second stream augmentation flows to Salado Creek, where reclaimed water replaces the flow from an abandoned artesian well. Also, reclaimed water is used in a decorative fountain at the City Convention Center with the fountain discharging into a dead-end channel of the downtown river walk waterway. Several agencies in southern California are evaluating the process in which reclaimed water would be delivered to streams in order to maintain a constant flow of highquality water for the enhancement of aquatic and wildlife habitat as well as to maintain the aesthetic value of the streams.

agement system. The treatment achieved in the subsurface environment may eliminate the need for costly advanced wastewater treatment processes. The ability to implement such treatment systems will depend on the method of recharge, hydrogeological conditions, requirements of the downgradient users, as well as other factors. Aquifers provide a natural mechanism for storage and subsurface transmission of reclaimed water. Irrigation demands for reclaimed water are often seasonal, requiring either large storage facilities or alternative means of disposal when demands are low. In addition, suitable sites for surface storage facilities may not be available, economically feasible, or environmentally acceptable. Groundwater recharge eliminates the need for surface storage facilities and the attendant problems associated with uncovered surface reservoirs, such as evaporation losses, algae blooms resulting in deterioration of water quality, and creation of odors. Aquifer storage and recovery (ASR) systems are being used in a number of states to overcome seasonal imbalances in both potable and reclaimed water projects. The tremendous volumes of storage potentially available in ASR systems means that a greater percentage of the resource, be it raw water or reclaimed water, can be captured for beneficial use. While there are obvious advantages associated with groundwater recharge, possible limitations include (Oaksford, 1985):


Groundwater Recharge

This section addresses planned groundwater recharge using reclaimed water with the specific intent to replenish groundwater. Although practices such as irrigation may contribute to groundwater augmentation, the replenishment is an incidental byproduct of the primary activity and is not discussed in this section. The purposes of groundwater recharge using reclaimed water may be: (1) to establish saltwater intrusion barriers in coastal aquifers, (2) to provide further treatment for future reuse, (3) to augment potable or nonpotable aquifers, (4) to provide storage of reclaimed water for subsequent retrieval and reuse, or (5) to control or prevent ground subsidence. Pumping of aquifers in coastal areas may result in saltwater intrusion, making them unsuitable as sources for potable supply or for other uses where high salt levels are intolerable. A battery of injection wells can be used to create a hydraulic barrier to maintain intrusion control. Reclaimed water can be injected directly into an aquifer to maintain a seaward gradient and thus prevent inland subsurface saltwater intrusion. This may allow for the additional development of inland withdrawals or simply the protection of existing withdrawals. Infiltration and percolation of reclaimed water takes advantage of the natural removal mechanisms within soils, including biodegradation and filtration, thus providing additional in situ treatment of reclaimed water and additional treatment reliability to the overall wastewater man-

Extensive land areas may be needed for spreading basins. Costs for treatment, water quality monitoring, and injection/infiltration facilities operations may be prohibitive. Recharge may increase the danger of aquifer contamination due to inadequate or inconsistent pretreatment. Not all recharged water may be recoverable due to movement beyond the extraction well capture zone or mixing with poor-quality groundwater. groundwater supply system (including the groundwater reservoir itself) is generally larger than that required for a surface water supply system. The fact that the aquifer does not compete with overlying land uses provides a significant advantage. However, this reservoir cannot adversely impact existing uses of the aquifer.




„ The area required for operation and maintenance of a


Figure 2-6.

Three Engineered Methods for Groundwater Recharge


Hydrogeologic uncertainties, such as transmissivity, faulting, and aquifer geometry, may reduce the effectiveness of the recharge project in meeting water supply demand. ter laws may not protect water rights and may present liability and other legal problems.

„ Inadequate institutional arrangements or groundwa-

The degree to which these factors might limit implementation of a groundwater recharge system is a function of the severity of the site specific impediments balanced against the need to protect existing water sources or expand raw water supplies.


Methods of Groundwater Recharge

quire water quality comparable to drinking water, if potable aquifers are affected. Low-technology treatment options for surface spreading basins include primary and secondary wastewater treatment with the possible use of lagoons and natural systems. Reverse osmosis is commonly used for direct injection systems to prevent clogging, however, some ASR systems have been operating successfully without membrane treatment when water was stored for irrigation. The cost of direct injection systems can be greatly reduced from the numbers presented in Table 2-8 if the aquifer is shallow and nonpotable. Vadose zone injection wells are a relatively new technology, and there is uncertainty over maintenance methods and requirements; however, it is clear that the removal of solids and disinfection is necessary to prevent clogging. Surface Spreading

Groundwater recharge can be accomplished by surface spreading, vadose zone injection wells, or direct injection. These methods of groundwater recharge use more advanced engineered systems as illustrated in Figure 2-6 (Fox, 1999). With the exception of direct injection, all engineered methods require the existence of an unsaturated aquifer. Table 2-8 provides a comparison of major engineering factors that should be considered when installing a groundwater recharge system, including the availability and cost of land for recharge basins (Fox, 1999). If such costs are excessive, the ability to implement injection wells adjacent to the reclaimed water source tends to decrease the cost of conveyance systems for injection wells. Surface spreading basins require the lowest degree of pretreatment while direct injection systems re-

Surface spreading is a direct method of recharge whereby the water moves from the land surface to the aquifer by infiltration and percolation through the soil matrix. An ideal soil for recharge by surface spreading would have the following characteristics:
„ Rapid infiltration rates and transmission of water „

No layers that restrict the movement of water to the desired unconfined aquifer No expanding-contracting clays that create cracks when dried that would allow the reclaimed water to



Table 2-8.

Comparison of Major Engineering Factors for Engineered Groundwater Recharge
Vadose Zone Injection Wells Unconfined Removal of Solids $25,000-75,000 per well 1,000-3,000 m /d per well Drying and Disinfection 5-20 Years Vadose Zone and Saturated Zone

Recharge Basins Aquifer Type Pretreatment Requirements Estimated Major Capital Costs (US$) Capacity Maintenance Requirements Estimated Life Cycle Soil AquiferTreatment Unconfined Low Technology Land and Distribution System 100-20,000 m /hectare-day Drying and Scraping >100 Years Vadose Zone and Saturated Zone

Direct Injection Wells Unconfined or Confined High Technology $500,000-1,500,000 per well 2,000-6,000 m /d per well Disinfection and Flow Reversal 25-50 Years Saturated Zone

bypass the soil during the initial stages of the flooding period
„ Sufficient clay and/or organic-rich sediment contents


Physical character and permeability of subsurface deposits

„ Depth to groundwater „

to provide large capacities to adsorb trace elements and heavy metals, as well as provide surfaces on which microorganisms can decompose organic constituents. The cation exchange capacity of clays also provides the capacity to remove ammonium ions and allow for subsequent nitrogen transformations

Specific yield, thickness of deposits, and position and allowable fluctuation of the water table Transmissivity, hydraulic gradients, and pattern of pumping lateral movement of groundwater


A supply of available carbon that would favor rapid denitrification during flooding periods, support an active microbial population to compete with pathogens, and favor rapid decomposition of introduced organics (Fox, 2002; Medema and Stuyfsand, 2002; Skjemstad et al., 2002). BOD and TOC in the reclaimed water will also be a carbon source

„ Structural and lithologic barriers to both vertical and

„ Oxidation state of groundwater throughout the receiv-

ing aquifer Although reclaimed water typically receives secondary treatment including disinfection and filtration prior to surface spreading, other treatment processes are sometimes provided. Depending on the ultimate use of the water and other factors (dilution, thickness of the unsaturated zone, etc.), additional treatment may be required. Nitrogen is often removed prior to surface spreading to eliminate concerns over nitrate contamination of groundwater and to simplify the permitting of storage systems as part of an overall reuse scheme. When extract water is used for potable purposes, post-treatment by disinfection is commonly practiced. In soil-aquifer treatment systems where the extracted water is to be used for nonpotable purposes, satisfactory water quality has been obtained at some sites using primary effluent for spreading providing that the hydraulic loading rates are low to prevent

Unfortunately, some of these characteristics are mutually exclusive, and the importance of each soil characteristic is dependent on the purpose of the recharge. For example, adsorption properties may be unimportant if recharge is primarily for storage. After the applied recharge water has passed through the soil zone, the geologic and subsurface hydrologic conditions control the sustained infiltration rates. The following geologic and hydrologic characteristics should be investigated to determine the total usable storage capacity and the rate of movement of water from the spreading grounds to the area of groundwater withdrawal:


the development of anaerobic conditions (Carlson et al., 1982 and Lance et al., 1980). For surface spreading of reclaimed water to be effective, the wetted surfaces of the soil must remain unclogged, the surface area should maximize infiltration, and the quality of the reclaimed water should not inhibit infiltration. Operational procedures should maximize the amount of water being recharged while optimizing reclaimed water quality by maintaining long contact times with the soil matrix. If nitrogen removal is desired and the major form of applied nitrogen is total kjehldal nitrogen, then maintenance of the vadose zone is necessary to allow for partial nitrification of ammonium ions adsorbed in the vadose zone. The depth to the groundwater table should be deep enough to prevent breakthrough of adsorbed ammonium to the saturated zone to ensure continuous and effective removal of nitrogen (Fox, 2002). Techniques for surface spreading include surface flooding, ridge and furrow systems, stream channel modifications, and infiltration basins. The system used is dependent on many factors such as soil type and porosity, depth to groundwater, topography, and the quality and quantity of the reclaimed water (Kopehynski et al., 1996). a. Surface Flooding Reclaimed water is spread over a large, gently sloped area (1 to 3 percent grade). Ditches and berms may enclose the flooding area. Advantages are low capital and operations and maintenance (O&M) costs. Disadvantages are large area requirements, evaporation losses, and clogging. b. Ridge and Furrow Water is placed in narrow, flat-bottomed ditches. Ridge and furrow is especially adaptable to sloping land, but only a small percentage of the land surface is available for infiltration. c. Stream Channel Modifications Berms are constructed in stream channels to retard the downstream movement of the surface water and, thus, increase infiltration into the underground. This method is used mainly in ephemeral or shallow rivers and streams where machinery can enter the streambeds when there is little or no flow to construct the berms and prepare the ground surface for recharge. Disadvantages may include a frequent need for re-

placement due to wash outs and possible legal restrictions related to such construction practices. d. Riverbank or Dune Filtration Riverbank and dune filtration generally rely on the use of existing waterways that have natural connections to groundwater systems. Recharge via riverbank or sand dune filtration is practiced in Europe as a means of indirect potable reuse. It is incorporated as an element in water supply systems where the source is untreated surface water, usually a river. The surface water is infiltrated into the groundwater zone through the riverbank, percolation from spreading basins, canals, lakes, or percolation from drain fields of porous pipe. In the latter 2 cases, the river water is diverted by gravity or pumped to the recharge site. The water then travels through an aquifer to extraction wells at some distance from the riverbank. In some cases, the residence time underground is only 20 to 30 days, and there is almost no dilution by natural groundwater (Sontheimer, 1980). In Germany, systems that do not meet a minimum residence time of 50 days are required to have post-treatment of the recovered water and similar guidelines are applied in the Netherlands. In the Netherlands, dune infiltration of treated Rhine River water has been used to restore the equilibrium between fresh and saltwater in the dunes (Piet and Zoeteman, 1980; Olsthoorn and Mosch, 2002), while serving to improve water quality and provide storage for potable water systems. Dune infiltration also provides protection from accidental spills of toxic contaminants into the Rhine River. Some systems have been in place for over 100 years, and there is no evidence that the performance of the system has deteriorated or that contaminants have accumulated. The City of Berlin has greater than 25 percent reclaimed water in its drinking water supply, and no disinfection is practiced after bank filtration. e. Infiltration Basins Infiltration basins are the most widely used method of groundwater recharge. Basins afford high loading rates with relatively low maintenance and land requirements. Basins consist of bermed, flat-bottomed areas of varying sizes. Long, narrow basins built on land contours have been effectively used. Basins constructed on highly permeable soils to achieve high hydraulic rates


are called rapid infiltration basins. Basin infiltration rates may sometimes be enhanced or maintained by creation of ridges within the basin (Peyton, 2002). The advantage of ridges within the basin is that materials that cause basin clogging accumulate in the bottom of the ridges while the remainder of the ridge maintains high infiltration rates. Rapid infiltration basins require permeable soil for high hydraulic loading rates, yet the soil must be fine enough to provide sufficient soil surfaces for biochemical and microbiological reactions, which provide additional treatment to the reclaimed water. Some of the best soils are in the sandy loam, loamy sand, and fine sand range. When the reclaimed water is applied to the spreading basin, the water percolates through the unsaturated zone to the saturated zone of the groundwater table. The hydraulic loading rate is preliminarily estimated by soil studies, but final evaluation is completed through operating in situ test pits or ponds. Hydraulic loading rates for rapid infiltration basins vary from 65 to 500 feet per year (20 to 150 meters per year), but are usually less than 300 feet per year (90 meters per year) (Bouwer, 1988). Though management techniques are site-specific and vary accordingly, some common principles are practiced in most infiltration basins. A wetting and drying cycle with periodic cleaning of the bottom is used to prevent clogging. Drying cycles allow for desiccation of clogging layers and re-aeration of the soil. This practice helps to maintain high infiltration rates, and microbial populations to consume organic matter, and helps reduce levels of microbiological constituents. Re-aeration of the soil also promotes nitrification, which is a prerequisite for nitrogen removal by denitrification. Periodic maintenance by cleaning of the bottom may be done by deep ripping of the soils or by scraping the top layer of soil. Deep ripping sometimes causes fines to migrate to deeper levels where a deep clogging layer may develop. The Orange County Water District (California) has developed a device to continuously remove clogging materials during a flooding cycle. Spreading grounds can be managed to avoid nuisance conditions such as algae growth and insect breeding in the percolation ponds. Generally, a number of basins are rotated through fill-

ing, draining, and drying cycles. Cycle length is dependent on both soil conditions and the distance to the groundwater table. This is determined through field-testing on a case-by-case basis. Algae can clog the bottom of basins and reduce infiltration rates. Algae further aggravate soil clogging by removing carbon dioxide, which raises the pH, causing precipitation of calcium carbonate. Reducing the detention time of the reclaimed water within the basins minimizes algal growth, particularly during summer periods where solar intensity and temperature increase algal growth rates. The levels of nutrients necessary to stimulate algal growth are too low for practical consideration of nutrient removal as a method to control algae. Also, scarifying, rototilling, or discing the soil following the drying cycle can help alleviate clogging potential, although scraping or “shaving” the bottom to remove the clogging layer is more effective than discing it. Removing the hard precipitant using an underwater machine has also been accomplished (Mills, 2002). Soil-Aquifer Treatment Systems

Soil-Aquifer Treatment (SAT) systems usually are designed and operated such that all of the infiltrated water is recovered via wells, drains, or seepage into surface water. Typical SAT recharge and recovery systems are shown in Figure 2-7. SAT systems with infiltration basins require unconfined aquifers, vadose zones free of restricting layers, and soils that are coarse enough to allow high infiltration rates, but fine enough to provide adequate filtration. Sandy loams and loamy or fine sands are the preferred surface soils in SAT systems. Recent work on SAT removal of dissolved organic carbon (DOC), trace organics, and organic halides has shown positive results (Fox et al., 2001; Drewes et al., 2001). The majority of trace organic compounds are removed by biodegradation and organic chlorine and organic bromine are removed to ambient levels. Short-term DOC removal is enhanced by maintaining aerobic conditions in the unsaturated zone (Fox, 2002). In the U.S., municipal wastewater usually receives conventional primary and secondary treatment prior to SAT. However, since SAT systems are capable of removing more BOD than is in secondary effluent, efficient secondary treatment may not be necessary in cases where the wastewater is subjected to SAT and subsequently reused for nonpotable purposes. Higher organic content may enhance nitrogen removal by denitrification in the SAT system and may enhance removal of synthetic organic compounds by stimulating greater microbiological activity in the soil. However low hydraulic loading


Figure 2-7.

Schematic of Soil-Aquifer Treatment Systems

rates must be used to prevent anaerobic conditions from developing which can prevent complete biodegradation in the sub-surface. More frequent cleaning of the basins would increase the cost of the SAT, but would not necessarily increase the total system cost. Where hydrogeologic conditions permit groundwater recharge with surface infiltration facilities, considerable improvement in water quality may be achieved through the movement of wastewater through the soil, unsaturated zone, and saturated zone. Table 2-9 provides an example of overall improvement in the quality of secondary effluent in a groundwater recharge SAT system. These water quality improvements are not limited to soil aquifer treatment systems and are applicable to most groundwater recharge systems where aerobic and/or anoxic conditions exist and there is sufficient storage time. These data are the result of a demonstration project in the Salt River bed, west of Phoenix, Arizona (Bouwer and Rice, 1989). The cost of SAT has been shown to be less than 40 percent of the cost of equivalent aboveground treatment (Bouwer, 1991). It should also be noted that the SAT product water was recovered from a monitoring well located adjacent to the recharge basin. Most SAT systems allow for considerable travel time in the aquifer and provide the opportunity for improvement in water quality. An intensive study, entitled, “An Investigation of Soil Aquifer Treatment for Sustainable Water Reuse,” was

conducted to assess the sustainability of several different SAT systems with different site characteristics and effluent pretreatments (AWWARF, 2001). (See case study 2.7.16). In all of the systems studied, water quality improvements were similar to the results presented by Bouwer (1984). When significant travel times in the vadose or saturated zone existed, water quality improvements exceeded the improvements actually observed by Bouwer (1984). The 3 main engineering factors that can affect the performance of soil aquifer treatment systems are: effluent pretreatment, site characteristics, and operating conditions (Fox, 2002). Effluent Pretreatment – Effluent pretreatment directly impacts the concentrations of biodegradable matter that are applied to a percolation basin. Therefore, it is a key factor that can be controlled as part of a SAT system. One of the greatest impacts of effluent pretreatment during SAT is near the soil/water interface where high biological activity is observed. This condition occurs because both the highest concentrations of biodegradable matter and oxygen are present. Both organic carbon and ammonia may be biologically oxidized. They are the water quality parameters that control the amount of oxygen demand in applied effluents. One of the greatest impacts of effluent pretreatment is to the total oxygen demand of applied water. Near the soil/water surface, biological activity with an effluent that has high total oxygen demand will result in the use of all the dissolved oxygen. Aerobic


Table 2-9.

Water Quality at Phoenix, Arizona, SAT System
Secondary Effluent (mg/l) Total dissolved solids Suspended solids Ammonium nitrogen Nitrate nitrogen Organic nitrogen Phosphate phosphorus Fluoride Boron Biochemical oxygen demand Total organic carbon Zinc Copper Cadmium Lead Fecal coliforms/100 mL a Viruses, pfu/100 mL b 750 11 16 0.5 1.5 5.5 1.2 0.6 12 12 0.19 0.12 0.008 0.082 3500 2118 Recovery W ell Samples (mg/l) 790 1 0.1 5.3 0.1 0.4 0.7 0.6 <1 1.9 0.03 0.016 0.007 0.066 0.3 <1

a Chlorinated effluent b Undisinfected effluent Source: Adapted from Bouwer and Rice, 1989. conditions can be maintained with effluents that have low total oxygen demand. It should also be noted that the majority of oxygen demand exerted during wetting is from the oxidation of organic carbon while ammonia is removed by adsorption (Kopchynski et al., 1996). Site Characteristics – Site characteristics are a function of local geology and hydrogeology. Site selection is often dependent on a number of practical factors including suitability for percolation, proximity to conveyance channels and/or water reclamation facilities, and the availability of land. The design of SAT systems must accommodate the site characteristics. The design options are primarily limited to the size and depth of percolation basins and the location of recovery wells. Increasing the depth of percolation basins can be done to access high permeability soils. The location of recovery wells affects the travel time for subsurface flow and mounding below the percolation basins. Operating Conditions – The operation of SAT systems with wet/dry cycles is a common operating strategy. The primary purpose of wet/dry cycle operation is to control the development of clogging layers and maintain high infiltration rates, and in some cases, to disrupt insect life cycles. As a clogging layer develops during a wetting cycle, infiltration rates can decrease to unacceptable rates. The drying cycle allows for the desiccation of the clogging layer and the recovery of infiltration rates during the next wetting cycle. Operating conditions are dependent on a number of environmental factors including temperature, precipitation and solar incidence. Therefore, operating conditions must be adjusted to both local site characteristics and weather patterns. Vadose Zone Injection

Vadose zone injection wells for groundwater recharge with reclaimed water were developed in the 1990s and have been used in several different cities in the Phoenix, Arizona, metropolitan area. Typical vadose zone injection wells are 6 feet (2 meters) in diameter and 100 to 150 feet (30 to 46 meters) deep. They are backfilled with porous media and a riser pipe is used to allow for water to enter at the bottom of the injection well to prevent air entrainment. An advantage of vadose zone injection wells is the significant cost savings as compared to direct injection wells. The infiltration rates per well are often similar to direct injection wells. A significant disadvantage is that they cannot be backwashed and a severely clogged well can be permanently destroyed. Therefore, reliable pretreatment is considered essential to maintaining the performance of a vadose zone injection well. Because of the considerable cost savings associated with vadose


zone injection wells as compared to direct injection wells, a life cycle of 5 years for a vadose injection well can still make the vadose zone injection well the economical choice. Since vadose zone injection wells allow for percolation of water through the vadose zone and flow in the saturated zone, one would expect water quality improvements commonly associated with soil aquifer treatment to be possible. Direct Injection

cern, such as NDMA and 1,4-dioxane into recovery wells. In these cases, the final pretreatment step was reverse osmosis. Since reverse osmosis effectively removes almost all nutrients, improvements in water quality by microbial activity might be limited in aquifers that receive reverse osmosis treated water. These emerging pollutants of concern have not been observed in soil aquifer treatment systems using spreading basins where microbial activity in the subsurface is stimulated. Ideally, an injection well will recharge water at the same rate as it can yield water by pumping. However, conditions are rarely ideal. Injection/withdrawal rates tend to decrease over time. Although clogging can easily be remedied in a surface spreading system by scraping, discing, drying and other methods, remediation in a direct injection system can be costly and time consuming. The most frequent causes of clogging are accumulation of organic and inorganic solids, biological and chemical contaminants, and dissolved air and gases from turbulence. Very low concentrations of suspended solids, on the order of 1 mg/l, can clog an injection well. Even low concentrations of organic contaminants can cause clogging due to bacteriological growth near the point of injection. Many criteria specific to the quality of the reclaimed water, groundwater, and aquifer material have to be taken into consideration prior to construction and operation. These include possible chemical reactions between the reclaimed water and groundwater, iron precipitation, ionic reactions, biochemical changes, temperature differences, and viscosity changes. Most clogging problems are avoided by proper pretreatment, well construction, and proper operation (Stuyzand, 2002). Injection well design and operations should consider the need to occasionally reverse the flow or backflush the well much like a conventional filter or membrane. In California and Arizona, injection wells are being constructed or retrofitted with dedicated pumping or backflushing equipment to maintain injection capacity and reduce the frequency of major well redevelopment events.

Direct injection involves pumping reclaimed water directly into the groundwater zone, which is usually a well-confined aquifer. Direct injection is used where groundwater is deep or where hydrogeological conditions are not conducive to surface spreading. Such conditions might include unsuitable soils of low permeability, unfavorable topography for construction of basins, the desire to recharge confined aquifers, or scarcity of land. Direct injection into a saline aquifer can create a freshwater “plume” from which water can be extracted for reuse, particularly in ASR systems (Pyne, 1995). Direct injection is also an effective method for creating barriers against saltwater intrusion in coastal areas. Direct injection requires water of higher quality than for surface spreading because of the absence of vadose zone and/or shallow soil matrix treatment afforded by surface spreading and the need to maintain the hydraulic capacity of the injection wells, which are prone to physical, biological, and chemical clogging. Treatment processes beyond secondary treatment that are used prior to injection include disinfection, filtration, air stripping, ion exchange, granular activated carbon, and reverse osmosis or other membrane separation processes. By using these processes or various subsets in appropriate combinations, it is possible to satisfy present water quality requirements for reuse. In many cases, the wells used for injection and recovery are classified by the EPA as Class V injection wells. Some states require that the injected water must meet drinking water standards prior to injection into a Class V well. For both surface spreading and direct injection, locating the extraction wells as great a distance as possible from the recharge site increases the flow path length and residence time in the underground, as well as the mixing of the recharged water with the natural groundwater. Treatment of organic parameters does occur in the groundwater system with time, especially in aerobic or anoxic conditions (Gordon et al., 2002; Toze and Hanna, 2002). There have been several cases where direct injection systems with wells providing significant travel time have allowed for the passage of emerging pollutants of con-


Fate of Contaminants in Recharge Systems

The fate of contaminants is an important consideration for groundwater recharge systems using reclaimed water. Contaminants in the subsurface environment are subject to processes such as biodegradation by microorganisms, adsorption and subsequent biodegradation, filtration, ion exchange, volatilization, dilution, chemical oxidation and reduction, chemical precipitation and complex formation, and photochemical reactions (in spreading basins) (Fox, 2002; Medema and Stuyzand, 2002). For surface spreading operations, chemical and micro-


biological constituents are removed in the top 6 feet (2 meters) of the vadose zone at the spreading site. Particulate Matter

Particles larger than the soil pores are strained off at the soil-water interface. Particulate matter, including some bacteria, is removed by sedimentation in the pore spaces of the media during filtration. Viruses are mainly removed by adsorption and interaction with anaerobic bacteria (Gordon et al., 2002). The accumulated particles gradually form a layer restricting further infiltration. Suspended solids that are not retained at the soil/water interface may be effectively removed by infiltration and adsorption in the soil profile. As water flows through passages formed by the soil particles, suspended and colloidal solids far too small to be retained by straining are thrown off the streamline through hydrodynamic actions, diffusion, impingement, and sedimentation. The particles are then intercepted and adsorbed onto the surface of the stationary soil matrix. The degree of trapping and adsorption of suspended particles by soils is a function of the suspended solids concentration, soil characteristics, and hydraulic loading. Suspended solids removal is enhanced by longer travel distances underground. For dissolved inorganic constituents to be removed or retained in the soil, physical, chemical, or microbiological reactions are required to precipitate and/or immobilize the dissolved constituents. Chemical reactions that are important to a soil’s capability to react with dissolved inorganics include cation exchange reactions, precipitation, surface adsorption, chelation, complexation, and weathering (dissolution) of clay minerals. While inorganic constituents such as chloride, sodium, and sulfate are unaffected by ground passage, many other inorganic constituents exhibit substantial removal. For example, iron and phosphorus removal in excess of 90 percent has been achieved by precipitation and adsorption in the underground, although the ability of the soil to remove these and other constituents may decrease over time. Heavy metal removal varies widely for different elements, ranging from 0 to more than 90 percent, depending on the speciation of the influent metals. Dissolved Organic Constituents

are indications that biodegradation is enhanced if the aquifer material is finely divided and has a high specific surface area, such as fine sand or silt. However, such conditions can lead to clogging by bacterial growths. Coarser aquifer materials such as gravel and some sands have greater permeability and, thus, less clogging. However, biodegradation may be less rapid and perhaps less extensive. The biodegradation of easily degradable organics occurs a short distance (few meters) from the point of recharge. A large body of literature shows that biodegradable compounds do not survive long in anoxic or aerobic groundwater and only chemical compounds that have high solubility and extensive half-lives are of great concern (i.e. chlorinated solvents). Specific groups of compounds also require longer times due to their complex biodegradation pathways; however, the product water from SAT may be compared to membrane processed water since select groups of compounds may persist in both cases (Drewes et al., 2003). The end products of complete degradation under aerobic conditions include carbon dioxide, sulfate, nitrate, phosphate, and water. The end products under anaerobic conditions include carbon dioxide, nitrogen, sulfide, and methane. The mechanisms operating on refractory organic constituents over long time periods typical of groundwater environments are not well understood. However, sustainable removal has been observed over significant time periods demonstrating that biodegradation is the major removal mechanism since accumulation of organic carbon in the sub-surface is not observed (AWWARF, 2001). The degradation of organic contaminants may be partial and result in a residual organic product that cannot be further degraded at an appreciable rate (Khan and Rorije, 2002), and such metabolites are often difficult to identify and detect (Drewes et al., 2001). Results were presented in a 2001 AWWARF study entitled, “An Investigation of Soil Aquifer Treatment for Sustainable Water Reuse.” This investigation demonstrated the potential removal ability of an entire SAT system where travel times are expected to be on the order of 6 months or greater before water is recovered. Since most trace organic compounds are present at concentrations that cannot directly support microbial growth, the sustainable removal mechanism for these compounds is co-metabolic. The microbes catalyze the mineralization of the organic compounds, but the microorganisms do not get enough energy from the trace organic compounds to support growth. In the study, the majority of compounds analyzed were below detection limits after 6 months of travel time in the sub-surface. Therefore, it appears that significant time in the sub-surface is required in a microbially active aquifer to efficiently remove trace organics that are potentially biodegradable by co-

Dissolved organic constituents are subject to biodegradation and adsorption during recharge. Biodegradation mainly occurs by microorganisms attached to the media surface (Skjemstad et al., 2002). The rate and extent of biodegradation is strongly influenced by the nature of the organic substances and by the presence of electron acceptors such as dissolved oxygen and nitrate. There


metabolism. One would expect similar results for aerobic or anoxic (nitrate-reducing) aquifers. But results are not conclusive for anaerobic aquifers. Several pharmaceutical compounds do appear to be recalcitrant in a microbially active aquifer at concentrations in the part per trillion range. A bench scale study of an unconfined aquifer irrigated with reclaimed water found antipyrine moved rapidly through the soil, while caffeine was subject to adsorption and microbial degradation (Babcock et al., 2002). Endocrine-disrupting activity has also been evaluated during soil aquifer treatment and results consistently suggest that soil aquifer treatment rapidly reduces endocrine-disrupting activity to ambient levels (Turney et al., In Press). Since the majority of compounds that are suspected to cause endocrine disruption are either strongly adsorbed or biodegradable, the results are consistent with microbial activity providing sustainable removal of organics during soil aquifer treatment. Nitrogen

The 2 major forms of nitrogen in reclaimed water are typically ammonia and nitrate. As reported by AWWARF (2001), the concentrations and forms of nitrogen in applied effluents are a strong function of effluent pretreatment. Secondary effluents contained ammonia nitrogen at concentrations up to 20 mg-N/l while denitrified effluents contained primarily nitrate nitrogen at concentrations less than 10 mg-N/l. Ammonia nitrogen is the major form of oxygen demand in secondary effluents that are not nitrified. Nitrogen can be efficiently removed during effluent pretreatment; however, appropriately operated SAT systems have the capacity to remove nitrogen in secondary effluents. The removal of nitrogen appears to be a sustainable, biologically mediated process. When ammonia is present in reclaimed water, the ammonia is removed by adsorption during wetting when insufficient oxygen is available to support nitrification. Nitrification of adsorbed ammonia occurs during subsequent drying cycles as re-aeration of vadose zone soils occurs. Nitrate is weakly adsorbed and is transported with bulk water flow during SAT. Removal of nitrate was consistently observed at all sites where anoxic or anaerobic conditions were present (AWWARF, 2001). The biological removal mechanism for denitrification was found to be site specific. The 2001 AWWARF study entitled, “An Investigation of Soil Aquifer Treatment for Sustainable Water Reuse.” investigated the mechanism of anaerobic ammonia oxidation (ANAMMOX) as a sustainable mechanism for ni-

trogen removal. During SAT, it is possible for adsorbed ammonia to serve as an electron donor to convert nitrate to nitrogen gas by ANAMMOX. Evidence for ANAMMOX activity was obtained in soils obtained from the Tucson site. Since adsorbed ammonia is available for nitrification when oxygen reaches soils containing adsorbed ammonia, ANAMMOX activity could occur as nitrate percolates through soils containing adsorbed ammonia under anoxic conditions. This implies that there is a sustainable mechanism for nitrogen removal during SAT when effluent pretreatment does not include nitrogen removal and the majority of applied nitrogen is ammonia. Appropriate wetting/drying cycles are necessary to promote nitrification in the upper vadose zone during drying cycles. The more mobile nitrate passes over soils with adsorbed ammonia under anoxic conditions deeper in the vadose zone. Extended wetting cycles with short dry cycles will result in ammonia adsorbed at increasing depths as adsorption sites become exhausted. Extended drying cycles will result in reaeration of soils at greater depths resulting in nitrification of adsorbed ammonia at greater depths. A mechanistic model was developed to provide guidelines for the operation of soil aquifer treatment systems to sustain nitrogen removal (Fox, 2003). Microorganisms

The survival or retention of pathogenic microorganisms in the subsurface depends on several factors including climate, soil composition, antagonism by soil microflora, flow rate, and type of microorganism. At low temperatures (below 4 °C or 39 °F) some microorganisms can survive for months or years. The die-off rate is approximately doubled with each 10 °C (18 oF) rise in temperature between 5 and 30 °C (41 and 86 °F) (Gerba and Goyal, 1985). Rainfall may mobilize bacteria and viruses that had been filtered or adsorbed, and thus, enhance their transport. The nature of the soil affects survival and retention. For example, rapid infiltration sites where viruses have been detected in groundwater were located on coarse sand and gravel types. Infiltration rates at these sites were high and the ability of the soil to adsorb the viruses was low. Generally, coarse soil does not inhibit virus migration. Other soil properties, such as pH, cation concentration, moisture holding capacity, and organic matter do have an affect on the survival of bacteria and viruses in the soil. Resistance of microorganisms to environmental factors depends on the species and strains present. Drying the soil will kill both bacteria and viruses. Bacteria survive longer in alkaline soils than in acid soils (pH 3 to 5) and when large amounts of organic matter are present. In general, increasing cation concentration and


decreasing pH and soluble organics tend to promote virus adsorption. Bacteria and larger organisms associated with wastewater are effectively removed after percolation through a short distance of the soil mantle. Lysimeter studies showed a greater than 99 percent removal of bacteria and 95 to 99 percent removal of viruses (Cuyk et al., 1999). Factors that may influence virus movement in groundwater are given in Table 2-10. Proper treatment (including disinfection) prior to recharge, site selection, and management of the surface spreading recharge system can minimize or eliminate the presence of microorganisms in the groundwater. Once the microorganisms reach the groundwater system, the oxidation state of the water significantly affects the rate of removal (Medema and Stuyfzand, 2002; Gordon et al., 2002).

One problem with recharge is that boundaries between potable and nonpotable aquifers are rarely well defined. Some risk of contaminating high quality potable groundwater supplies is often incurred by recharging “nonpotable” aquifers. The recognized lack of knowledge about the fate and long-term health effects of contaminants found in reclaimed water obliges a conservative approach in setting water quality standards and monitoring requirements for groundwater recharge. Because of these uncertainties, some states have set stringent water quality requirements and require high levels of treatment – in some cases, organic removal processes – where groundwater recharge impacts potable aquifers.


Augmentation of Potable Supplies


Health and Regulatory Considerations

Constraints on groundwater recharge are conditioned by the use of the extracted water and include health concerns, economic feasibility, physical limitations, legal restrictions, water quality constraints, and reclaimed water availability. Of these constraints, health concerns are the most important as they pervade almost all recharge projects (Tsuchihashi et al., 2002). Where reclaimed water will be ingested, health effects due to prolonged exposure to low levels of contaminants must be considered as well as the acute health effects from pathogens or toxic substances. [See Section 3.4.1 Health Assessment of Water Reuse and Section 2.6 Augmentation of Potable Supplies.] Table 2-10.

This section discusses indirect potable reuse via surface water augmentation, groundwater recharge, and direct potable reuse. For the purpose of this document, indirect potable reuse is defined as the augmentation of a community’s raw water supply with treated wastewater followed by an environmental buffer (Crook, 2001). The treated wastewater is mixed with surface and/or groundwater, and the mix typically receives additional treatment before entering the water distribution system. Direct potable reuse is defined as the introduction of treated wastewater directly into a water distribution system without intervening storage (pipe-to-pipe) (Crook, 2001). Both such sources of potable water are, at face value, less desirable than using a higher quality source for drinking.

Factors that May Influence Virus Movement to Groundwater
Factor Comments Fine-textured soils retain viruses more effectively than light-textured soils. Iron oxides increase the adsorptive capacity of soils. Muck soils are generally poor adsorbents. Generally, adsorption increases when pH decreases. However, the reported trends are not clearcut due to complicating factors. Adsorption increases in the presence of cations. Cations help reduce repulsive forces on both virus and soil particles. Rainwater may desorb viruses from soil due to its low conductivity. Generally compete with viruses for adsorption sites. No significant competition at concentrations found in wastewater effluents. Humic and fulvic acids reduce virus adsorption to soils. Adsorption to soils varies with virus type and strain. Viruses may have different isoelectric points. The higher the flow rate, the lower virus adsorption to soils. Virus movement is less under unsaturated flow conditions.

Soil Type pH


Soluble Organics Virus Type Flow Rate Saturated vs. Unsaturated Flow

Source: Gerba and Goyal, 1985.


A guiding principle in the development of potable water supplies for almost 150 years was stated in the 1962 Public Health Service Drinking Water Standards: “. . . water supply should be taken from the most desirable source which is feasible, and efforts should be made to prevent or control pollution of the source.” This was affirmed by the EPA (1976) in its Primary Drinking Water Regulations: “ . . priority should be given to selection of the purest source. Polluted sources should not be used unless other sources are economically unavailable. . . “

compounds under the NPDWR as outlined by the 1986 and 1996 SDWA amendments. MCLs are thought of as standards for individual chemicals. However, contaminants can be regulated by specifying treatment processes and performance standards without directly measuring the contaminant. Because of the sheer numbers of potential chemicals, traditional wastewater treatment processes are not the panacea for all potable water quality concerns, particularly since current analytical methods are insufficient to identify all potential contaminants at concentrations of health significance. If the analytical method does not have sufficient sensitivity, then the presence of contaminants may go unobserved. Water reuse agencies in California observed problems with specific chemicals and trace organics being discharged to wastewater treatment plants. These elements were detected in the final effluents, only after analytical detection limits were lowered. Additional concerns have been raised regarding the fate and transport of trace organic compounds (Daughton and Temes 1999 and Sedlak et al., 2000). These include endocrine disruptors, pharmaceuticals, hormones, antibiotics, anti-inflammatories, and personal care products (antibacterial soaps, sunscreen, bath gels, etc.) that are present in municipal wastewaters. None of these individual compounds are regulated or monitored by maximum contaminant levels (MCLs) in the SDWA. Some indirect water reuse projects (San Diego and Denver) have started using toxicological assays to compare the drinking water source to the reclaimed water. While these studies have generally shown that the assay results show no difference between the reclaimed water and the source water used for domestic supply, there are concerns that current toxicological methods are not sensitive enough to characterize the impact of reclaimed water on human health in the 10-4 and 10-6 risk range. As part of the 1996 SDWA amendments, EPA is charged with developing an evaluation that considers the health impact of an identified contaminant to sensitive subpopulations. In 1996 and 1999, the Rand Corporation conducted epidemiological studies to monitor the health of those consuming reclaimed water in Los Angeles County (Sloss et al., 1996 and Sloss et al., 1999). The 1996 ecologic study design looked at selected infectious disease occurrence as well as cancer incidence and mortality. Investigators could find no link between the incidence of infectious disease or cancer rates and exposure to reclaimed water. The 1999 study focused on adverse birth outcomes (prenatal development, infant mortality, and birth defects). Similar results were reported for the 1999 study; there was no association between reclaimed water and adverse


Water Quality Objectives for Potable Reuse

Development of water quality requirements for either direct or indirect potable reuse is difficult. The task involves a risk management process that entails evaluating, enumerating, and defining the risks and potential adverse health impacts that are avoided by the practice of physically separating wastewater disposal and domestic water supply. By physically separating wastewater disposal and domestic water supply by environmental storage, the life cycle of waterborne diseases can be broken, thereby preventing or reducing disease in the human population. As the physical proximity and perceived distance between reclaimed water and domestic water supply decreases, human contact with and consumption of reclaimed water become more certain, and the potential impacts to human health become harder to define. From a regulatory standpoint, there is a tendency to use the Safe Drinking Water Act (SDWA) National Primary Drinking Water Regulations (NPDWR) as a starting point for defining potable water quality objectives. For years, water reuse advocates have argued that reclaimed water from municipal wastewater meets the requirements of the NPDWR. However, the original purpose of the NPDWR was not intended to define potable water quality when the source is municipal wastewater. There has been a dramatic increase in the ability to detect chemicals in recent years. Considering the hundreds of thousands of chemicals manufactured or used in the manufacturing of products, the number of chemicals regulated by the SDWA represent a small fraction of these compounds. The 1986 SDWA amendments required EPA to promulgate 25 new maximum contaminant levels (MCLs), or drinking water treatment requirements, for specific contaminants every 3 years (Calabrese et al. 1989). However, the 1996 SDWA amendments reduced that number by requiring the agency to “consider” regulating up to 5 contaminants every 5 years. Figure 2-8 shows the potential impact to the number of regulated


Figure 2-8.

Contaminants Regulated by the National Primary Drinking Water Regulations

birth outcomes. However, epidemiological studies are limited, and these studies are no exception. Researchers noted several weaknesses in their study design that contribute to the overall uncertainty associated with the findings. They found that it was difficult to get an accurate assessment of reclaimed water exposure in the different areas. In addition to the uncertainties associated with toxicological and epidemiological studies, current analytical systems are insensitive to the contaminants of concern. Surrogates are often used as performance-based standards. Microbiological water quality objectives are defined by surrogates or treatment performance standards that do not measure the contaminant of concern, but nevertheless, provide some indication the treatment train is operating properly, and the product is of adequate quality. It is then assumed that under similar conditions of operation, the microbiological contaminant of concern is being removed concurrently. For example, coliforms are an indicator of microbiological water quality. While there are documents discussing the criteria for an ideal surrogate (AWWARF and KIWA, 1988), no surrogate meets every criterion. Hence, the shortcomings of the surrogate should also be remembered. In 1998, the National Research Council (NRC) published, “Issues in Potable Reuse,” an update of its 1980 report. In this update, the NRC did not consider addressing direct potable reuse for the reason that, without added protection (such as storage in the environment), the NRC did not view direct potable reuse as a viable option. Rather than face the risks associated with direct, pipe-to-pipe

potable reuse, the NRC emphasized that there are far more manageable, nonpotable reclaimed water applications that do not involve human consumption. The focus of health impacts shifts from the acute microbiologicallyinduced diseases, for nonpotable reuse, to the diseases resulting from long-term chronic exposure, e.g., cancer or reproductive effects, for potable reuse. While direct potable reuse may not be considered a viable option at this time, many states are moving forward with indirect potable reuse projects. For many cities or regions, the growing demand for water, lack of new water resources, and frequent calls for water conservation in low and consecutive low rainfall years have resulted in the need to augment potable supplies with reclaimed water. Indeed, in some situations, indirect potable reuse may be the next best alternative to make beneficial use of the resource. Further, the lack of infrastructure for direct nonpotable reuse may be too cumbersome to implement in a timely manner. With a combination of treatment barriers and added protection provided by environmental storage, the problem of defining water quality objectives for indirect potable reuse is manageable. By employing treatment beyond typical disinfected tertiary treatment, indirect potable reuse projects will provide additional organics removal and environmental storage (retention time) for the reclaimed water, thereby furnishing added protection against the unknowns and uncertainty associated with trace organics. However, these processes will be operated using performance standards based on surrogates that do not address specific contaminants. Until better


source control and protection programs are in place to deal with the myriad of chemicals discharged into the wastewater collection systems, or until analytical and toxicological testing becomes more sensitive, the concern over low-level contaminant concentrations will remain. If and when contaminants are found, treatment technologies can be applied to reduce the problem. EPA (2001) has identified several drinking water treatment processes capable of removing some endocrine disruptors. Examples are granular activated carbon and membrane treatment. Potable reuse, whether direct or indirect, is not a riskfree practice. No human engineered endeavor is risk-free, but with appropriate treatment barriers (and process control) water quality objectives will be defined by an acceptable risk. Given the unknowns, limitations, and uncertainty with the current state of science and technology, it is not possible to establish the threshold at which no observed effect would occur, just as it is not reasonable to expect current scientific techniques to demonstrate the absence of an impact on human health.

More recent indirect potable reuse projects that involve surface water augmentation are exemplified by the Upper Occoquan Sewage Authority (UOSA) treatment facilities in northern Virginia, which discharge reclaimed water into Bull Run, just above Occoquan Reservoir, a water supply source for Fairfax County, Virginia. The UOSA plant, in operation since 1978, provides AWT that is more extensive than required treatment for nonpotable reuse and accordingly provides water of much higher quality for indirect potable reuse than is required for nonpotable reuse (Joint Task Force, 1998). In Clayton County, Georgia, wastewater receives secondary treatment, and then undergoes land treatment, with the return subsurface flow reaching a stream used as a source of potable water. The Clayton County project, which has been in operation for 20 years, is being upgraded to include wetlands treatment and enhancements at the water treatment plant (Thomas et al., 2002). While UOSA now provides a significant portion of the water in the system, varying from an average of about 7 percent of the average annual flow to as much as 80-90 percent during drought periods, most surface water augmentation indirect potable reuse projects have been driven by requirements for wastewater disposal and pollution control. Their contributions to increased public water supply were incidental. In a comprehensive, comparative study of the Occoquan and Clayton County projects, the water quality parameters assessed were primarily those germane to wastewater disposal and not to drinking water (Reed and Bastian, 1991). Most discharges that contribute to indirect potable water reuse, especially via rivers, are managed as wastewater disposal functions and are handled in conformity with practices common to all water pollution control efforts. The abstraction and use of reclaimed water is almost always the responsibility of a water supply agency that is not related politically, administratively, or even geographically to the wastewater disposal agency (except for being downstream). Increasing populations and a growing scarcity of new water sources have spurred a small but growing number of communities to consider the use of highly-treated municipal wastewater to augment raw water supplies. This trend toward planned, indirect potable reuse is motivated by need, but made possible through advances in treatment technology. These advances enable production of reclaimed water to almost any desired quality. Planned, indirect potable reuse via surface water augmentation and groundwater recharge is being practiced in the U.S. and elsewhere. Notwithstanding the fact that some proposed, high profile, indirect potable reuse projects have been defeated in recent years due to public or political opposition to perceived health concerns, indirect potable reuse will likely increase in the future.


Surface Water Augmentation for Indirect Potable Reuse

For many years, a number of cities have elected to take water from large rivers that receive substantial wastewater discharges. These cities based their decisions, in part, on the assurance that conventional filtration and disinfection eliminates the pathogens responsible for waterborne infectious disease. These water sources were generally less costly and more easily developed than upland supplies or underground sources. Such large cities as Philadelphia, Cincinnati, and New Orleans, drawing water from the Delaware, Ohio and Mississippi Rivers, respectively, are thus practicing indirect potable water reuse. The many cities upstream of their intakes can be characterized as providing water reclamation in their wastewater treatment facilities, although they were not designed, nor are they operated, as potable water sources. NPDES permits for these discharges are intended to make the rivers “fishable and swimmable,” and generally do not reflect potable water requirements downstream. These indirect potable reuse systems originated at a time when the principal concern for drinking water quality was the prevention of enteric infectious diseases and issues relating to chemical contaminants received lesser attention. Nevertheless, most cities do provide water of acceptable quality that meets current drinking water regulations. Unplanned or incidental indirect potable reuse via surface water augmentation has been, and will continue to be, practiced widely.



Groundwater Recharge for Indirect Potable Reuse

As mentioned in Section 2.5.1, Methods of Groundwater Recharge, groundwater recharge via surface spreading or injection has long been used to augment potable aquifers. Although both planned and unplanned recharge into potable aquifers has occurred for many years, few healthrelated studies have been undertaken. The most comprehensive health effects study of an existing groundwater recharge project was carried out in Los Angeles County, California, in response to uncertainties about the health consequences of recharge for potable use raised by a California Consulting Panel in 1975-76. In November 1978, the County Sanitation Districts of Los Angeles County (Districts) initiated the “Health Effects Study,” a $1.4-million-project designed to evaluate the health effects of using treated wastewater for groundwater recharge based on the recommendations of the 1976 Consulting Panel. The focus of the study was the Montebello Forebay Groundwater Replenishment Project, located within the Central Groundwater Basin in Los Angeles County, California. Since 1962, the Districts’ reclaimed water has been blended with imported river water (Colorado River and State Project water) and local stormwater runoff, and used for replenishment purposes. The project is managed by the Water Replenishment District of Southern California (WRD) and is operated by the Los Angeles County Department of Public Works. The Central Groundwater Basin is adjudicated; 85 groundwater agencies operate over 400 active wells. Water is percolated into the groundwater using 2 sets of spreading grounds: (1) the Rio Hondo Spreading Grounds consist of 570 acres (200 hectares) with 20 individual basins and (2) the San Gabriel River Spreading Grounds consist of 128 acres (52 hectares) with 3 individual basins and portions of the river. The spreading basins are operated under a wetting/drying cycle designed to optimize inflow and discourage the development of vectors. From 1962 to 1977, the water used for replenishment was disinfected secondary effluent. Filtration (dual-media or mono-media) was added later to enhance virus inactivation during final disinfection. By 1978, the amount of reclaimed water spread averaged about 8.6 billion gallons per year (33 x 103 m3 per year) or 16 percent of the total inflow to the groundwater basin with no more than about 10.7 billion gallons (40 million m3) of reclaimed water spread in any year. The percentage of reclaimed water contained in the extracted potable water supply ranged from 0 to 11 percent on a long-term (1962-1977) basis (Crook et al., 1990).

The primary goal of the Health Effects Study was to provide information for use by health and regulatory authorities to determine if the use of reclaimed water for the Montebello Forebay Project should be maintained at the present level, cut back, or expanded. Specific objectives were to determine if the historical level of reuse had adversely affected groundwater quality or human health, and to estimate the relative impact of the different replenishment sources on groundwater quality. Specific research tasks included:
„ Water quality characterizations of the replenishment

sources and groundwater in terms of their microbiological and chemical content.

Toxicological and chemical studies of the replenishment sources and groundwater to isolate and identify organic constituents of possible health significance Field studies to evaluate the efficacy of soil for attenuating chemicals in reclaimed water Hydrogeologic studies to determine the movement of reclaimed water through groundwater and the relative contribution of reclaimed water to municipal water supplies Epidemiologic studies of populations ingesting reclaimed water to determine whether their health characteristics differed significantly from a demographically similar control population




During the course of the study, a technical advisory committee and a peer review committee reviewed findings and interpretations. The final project report was completed in March, 1984 as summarized by Nellor et al. in 1985. The results of the study did not demonstrate any measurable adverse effects on either the area groundwater or health of the people ingesting the water. Although the study was not designed to provide data for evaluating the impact of an increase in the proportion of reclaimed water used for replenishment, the results did suggest that a closely monitored expansion could be implemented. In 1986, the State Water Resources Control Board, Department of Water Resources and Department of Health Services established a Scientific Advisory Panel on Groundwater Recharge to review the report and other pertinent information. The Panel concluded that it was comfortable with the safety of the product water and the continuation of the Montebello Forebay Project. The Panel felt that the risks, if any, were small and probably


not dissimilar from those that could be hypothesized for commonly used surface waters. Based on the results of the Health Effects Study and recommendations of the Scientific Advisory Panel, the Regional Water Quality Control Board in 1987 authorized an increase in the annual quantity of reclaimed water to be used for replenishment from 32,700 acre-feet per year to 50,000 acre-feet per year (20,270 gpm to 31,000 gpm or 1,280 to 1,955 l/s). In 1991, water reclamation requirements for the project were revised to allow for recharge up to 60,000 acre-feet per year (37,200 gpm or 2,350 l/s) and 50 percent reclaimed water in any one year as long as the running 3-year total did not exceed 150,000 acrefeet per year (93,000 gpm or 5,870 l/s) or 35 percent reclaimed water. The average amount of reclaimed water spread each year is about 50,000 acre-feet per year (31,000 gpm or 1,955 l/s). Continued evaluation of the project is being provided by an extensive sampling and monitoring program, and by supplemental research projects pertaining to percolation effects, epidemiology, and microbiology. The Rand Corporation has conducted additional health studies for the project as part of an ongoing effort to monitor the health of those consuming reclaimed water in Los Angeles County (Sloss et al., 1996 and Sloss et. al., 1999). These studies looked at health outcomes for 900,000 people in the Central Groundwater Basin who are receiving some reclaimed water in their household water supplies. These people account for more than 10 percent of the population of Los Angeles County. To compare health characteristics, a control area of 700,000 people that had similar demographic and socioeconomic characteristics was selected, but did not receive reclaimed water. The results from these studies have found that, after almost 30 years of groundwater recharge, there is no association between reclaimed water and higher rates of cancer, mortality, infectious disease, or adverse birth outcomes. The Districts, along with water and wastewater agencies and researchers in 3 western states, are currently conducting research to evaluate the biological, chemical, and physical treatment processes that occur naturally as the reclaimed water passes through the soil on the way to the groundwater. The SAT Project was developed to better understand the impact of SAT on water quality in terms of chemical and microbial pollutants (see Case Study 2.7.16). This work will continue to address emerging issues such as the occurrence and significance of pharmaceutically active compounds (including endocrine disruptors and new disinfection byproducts) and standardized monitoring techniques capable of determining pathogen viability. The Groundwater Replenishment

(GWR) System is an innovative approach to keeping the Orange County, California, groundwater basin a reliable source for meeting the region’s future potable water needs (Chalmers et al., 2003). A joint program of the Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD), the GWR System will protect the groundwater from further degradation due to seawater intrusion and supplement existing water supplies by providing a new, reliable, high-quality source of water to recharge the Orange County Groundwater Basin (see Case Study 2.7.15).


Direct Potable Water Reuse

Direct potable reuse is currently practiced in only one city in the world, Windhoek, Namibia. This city uses direct potable reuse on an intermittent basis only. In the U.S., the most extensive research focusing on direct potable reuse has been conducted in Denver, Colorado; Tampa, Florida; and San Diego, California. A considerable investment in potable reuse research has been made in Denver, Colorado, over a period of more than 20 years. This research included operation of a 1-mgd (44-l/s) reclamation plant in many different process modes over a period of about 10 years (Lauer, 1991). The product water was reported to be of better quality than many potable water sources in the region. The San Diego Total Resource Recovery Project was executed to demonstrate the feasibility of using natural systems for secondary treatment with subsequent advanced wastewater treatment to provide a water supply equivalent or better than the quality of imported water supplied to the region (WEF/ AWWA, 1988). Tables 2-11 and 2-12 show the advanced wastewater treatment effluent concentrations of minerals, metals, and trace organics for the San Diego Project. Microbial analysis performed over a 2.5-year period, showed that water quality of advanced wastewater treatment effluent was low in infectious agents. Specifically, research showed:
„ Spiking studies were conducted to determine the re-

moval level of viruses. Results of 4 runs showed an overall virus removal rate through the primary, secondary, and advanced wastewater treatment plants of between 99.999 9 percent and 99.999 99 percent. Levels of removal were influenced by the number of viruses introduced. Viruses were not detected in more than 20.2 x 104 l of sample.
„ Enteric bacterial pathogens (that is, Salmonella, Shi-

gella, and Campylobacter) were not detected in 51 samples of advanced wastewater treatment effluent.
„ Protozoa and metazoa of various types were absent


in the advanced wastewater treatment effluent. Giardia lamblia were not recovered, and based on recovery rates of cysts from raw wastewater, removal rates were estimated to be 99.9 percent (WEF/ AWWA, 1998) The treatment train operated in San Diego, after secondary treatment, includes the following processes:
„ Coagulation with ferric chloride „ Multimedia filtration „ „


Reverse osmosis

Most of these unit processes are well understood. Their performance can be expected to be effective and reliable in large, well-managed plants. However, the heavy burden of sophisticated monitoring for trace contaminants that is required for potable reuse may be beyond the capacity of smaller enterprises. The implementation of direct, pipe-to-pipe, potable reuse is not likely to be adopted in the foreseeable future in the U.S. for several reasons:
„ Many attitude (opinion) surveys show that the public

Ultraviolet disinfection pH adjustment with sulfuric acid

will accept and endorse many types of nonpotable reuse while being reluctant to accept potable reuse. In general, public reluctance to support reuse in-

„ Cartridge filter

Table 2-11.

Physical and Chemical Sampling Results from the San Diego Potable Reuse Study
Minimum Detection Limit 15 na 1 1 4 0.13 0.1 0.01 0.05 1 0.2 0.1 0.1 1 0.01 0.5 0.008 0.5 1 0.005 Number of Samples < MDL 6 892 68 85 96 13 69 13 91 28 39 96 24 16 20 16 18 14 20 15

Constituents General COD pH SS TOC Anions Chloride Fluoride Ammonia Nitrite Nitrate Phosphate Silicate Sulfate Cations Boron Calcium Iron Magnesium Manganese Potassium Sodium Zinc

Number of Samples


Arithmetic Mean

Standard Deviation

90th Percentile

611 892 116 611 97 37 71 37 91 88 39 96 24 21 21 21 21 21 21 20

mg/L ⎯ mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L

<15.0 8.2 1.6 <1.0 33.93 <0.125 1.26 <0.01 1.81 <1.00 1.2 6.45 0.24 3.817 0.054 1.127 0.011 0.608 16.999 0.009

44.8 0.2 3.5

2.7 ⎯ 5.6 1.1 81.1 0.241 2.92 0.03 5.77 2.2 1.83 14.6 0.368 3.87 0.135 7.89 0.042 3.42 54.2 0.02

3.0a 31.39 0.33 2.04 0.05 2.70



0.42 5.72 0.085 12.262 0.077 6.706 0.041 2.599 15.072 0.008

Analysis gave negative result for mean. Source: WEF/AWWA, 1998.


Table 2-12.

San Diego Potable Reuse Study: Heavy Metals and Trace Organics Results

Constituents Metals Arsenic Cadmium Chromium Copper Lead Mercury Nickel Selenium Silver Organics Bis (2-ethyl hexyl phthalate) Benzyl/butyl phthalate Bromodichloromethane Chloroform Dibutyl phthalate Dimethylphenol Methyl chloride Naphthalene 1,1,1 – Trichloroethane 1,2 – Dichlorobenzene 4 - Nitrophenol Pentachlorophenol Phenol
a b

Number of Samples


Minimum Detection Limit

Number of Samples > MDL 5 1 10 18 15 0 19 2 2 6 1 0 0 1 0 6 0 0 0 0 0 0

Arithmetic Mean

Standard Deviation

11 10 19 20 18 8 20 12 16 33 33 33 33 33 33 33 33 33 33 33 33 33

µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L

1 1 1 6 1 1 1.2 6 5 2.5 2.5 3.1 1.6 2.5 2.7 2.8 1.6 3.8 4.4 2.4 3.6 1.5

<1 1 2 18 3 1 6 4 3 <2.50 2.5 3.1 1.6 2.64 2.7 <2.80 1.6 3.8 4.4 2.4 3.6 1.5

8 0.3 3 20 7 0c 7 3 4


3.27b 0.02c 0.00c 0.00c 0.78 7.91 0 0 0 0 0 0


<MDL was taken to be equal to MDL. Analysis gave negative result for mean. c Statistics were calculated using conventional formulas. Source: WEF/AWWA, 1998. creases as the degree of human contact with reclaimed water increases. Further, public issues have been raised relevant to potential health impacts which may be present in reclaimed water.
„ Indirect potable reuse is more acceptable to the pub-

passes through the environment.
„ Direct potable reuse will seldom be necessary. Only

lic than direct potable reuse, because the water is perceived to be “laundered” as it moves through a river, lake, or aquifer (i.e. the Montebello Forebay and El Paso projects). Indirect reuse, by virtue of the residence time in the watercourse, reservoir or aquifer, often provides additional treatment. Indirect reuse offers an opportunity for monitoring the quality and taking appropriate measures before the water is abstracted for distribution. In some instances, however, water quality may actually be degraded as it

a small portion of the water used in a community needs to be of potable quality. While high quality sources will often be inadequate to serve all urban needs in the future, the use of reclaimed water to replace potable quality water for nonpotable purposes will release more high quality potable water for future use.


Case Studies

The following case studies are organized by category of reuse applications:


Urban Industrial Agricultural Environmental and Recreational Groundwater Recharge Augmentation of Potable Supplies Miscellaneous

Sections 2.7.1 through 2.7.6 Sections 2.7.7 through 2.7.8 Sections 2.7.9 through 2.7.12 Section 2.7.13 Section 2.7.14 through 2.7.16 Section 2.7.17 Section 2.7.18 through 2.7.19

mixing and cleanup), cooling tower make up, fire fighting (suppression and protection), irrigation of all types of vegetation and landscaping, and all of the nonpotable needs for clean water within the treatment facility. All product water bound for the reuse system is metered. There is a master meter at the master pumping station, and all customers are metered individually at the point of service. Rates are typically set at 75 to 80 percent of the potable water rate to encourage connection and use. Rates are based on volumetric consumption to discourage wasteful practices. New customers are required by tariff to connect to and use the reclaimed water system. If the system is not available, new customers are required to provide a single point of service to facilitate future connection. Existing customers using potable water for nonpotable purposes are included in a master plan for future conversion to reclaimed water. Demands for reclaimed water have sometimes exceeded supply capabilities, especially during the months of April and May, when rainfall is lowest and demand for irrigation is at its highest. RCID has a number of means at its disposal to counteract this shortfall. The primary means uses 2, formerly idle, potable water wells to supplement the reclaimed water systems during high demand. These wells can provide up to 5,000 gpm (315 l/s) of additional supply. A secondary means requests that major, selected customers return to their prior source of water. Two of the golf courses can return to surface waters for their needs and some of the cooling towers can be quickly converted to potable water use (and back again). Total water demand within RCID ranges from 18 to 25 mgd (180 to 1,100 l/s) for potable and nonpotable uses. Reclaimed water utilization accounts for 25 to 30 percent of this demand. Over 6 mgd (260 l/s) is typically consumed on an average day and peak day demands have exceeded 12 mgd (525 l/s). Providing reclaimed water for nonpotable uses has enabled RCID to remain within its consumptive use permit limitations for groundwater withdrawal, despite significant growth within its boundaries. Reclaimed water has been a major resource in enabling RCID to meet water use restrictions imposed by the water management districts in alleviating recent drought impacts. Figure 2-9 is a stacked bar graph that shows the historical contribution reclaimed water has made to the total water resource picture at RCID. The continued growth of the RCID reclaimed water system is expected to play an ever-increasing and critical role in meeting its water resource needs. Because alternative sources of water (e.g., surface water, brackish water, and stormwater) are not easily and reliably available and are prohibitively costly to obtain, it makes eco-


Water Reuse at Reedy Creek Improvement District

Reedy Creek Improvement District (RCID) provides municipal services to the Walt Disney World Resort Complex, located in Central Florida. In 1989, RCID faced a challenge of halting inconsistent water quality discharges from its wetland treatment system. The solution was a twofold approach: (1) land was purchased for the construction of rapid infiltration basins (RIBs) and (2) plans were drafted for the construction of a reuse distribution system. The RIBs were completed in 1990. Subsequently, all surface water discharges ceased. The RIBs recharge the groundwater via percolation of applied effluent to surficial sands and sandy clays. Eighty–five 1acre basins were built and operate on a 6 to 8 week rotational cycle. Typically, 10 or 11 basins are in active service for a 1-week period; while the remaining basins are inactive and undergo maintenance by discing of the bottom sands. Initially, the RIBs served as the primary mechanism for reuse and effluent disposal, receiving 100 percent of the effluent. But the trend has completely reversed in recent years, and the RIBs serve primarily as a means of wet-weather recharge or disposal of sub-standard quality water. The majority of the effluent is used for public access reuse. In the past 3 years, over 60 percent of the effluent volume was used for public access reuse. Initially, the reclaimed water distribution system served 5 golf courses and provided some landscape irrigation within RCID. In the past 10 years, the extent and diversity of uses has grown and now includes washdown of impervious surfaces, construction (such as concrete


Figure 2-9.

Water Resources at RCID

nomic sense for RCID to maximize its use of reclaimed water.


Estimating Potable Water Conserved in Altamonte Springs due to Reuse

It is taken for granted that implementing a reclaimed water system for urban irrigation will conserve potable water, but few efforts have been made to quantify the benefits. An analysis was performed to define the potential value of urban reuse for a moderately sized city, Altamonte Springs, Florida. Altamonte Springs began implementing its reclaimed water system in 1990. First, annual potable water-use data were analyzed to ascertain if a significant difference could be seen between periods before and after reuse. Figure 2-10 shows the historical potable water demands from 1977 to 2000, expressed as gallons of water used per capita per day. Figure 2-10 indicates a much greater potable water demand before reuse was implemented than after. In 1990, the demand dropped by about 20 gallons per capita-day (76 liters per capita-day) in just one year. Two differing methods were used to estimate the total potable water conserved through implementing a re-

claimed water system. The first method, a linear extrapolation model (LEM), assumes that the rate of increasing water use per capita for 1990 to 2000 increases as it did from 1977 to 1989. Then, the amount conserved per year can be estimated by taking the difference in the potential value from the linear model and the actual potable water used. Figure 2-11 predicts the amount of potable water saved by implementing the reuse system from 1990 to 2000. The other method used a more conservative, constant model (CCM). This model averages the gallons of potable water per capita-day from the years before reuse and assumes that the average is constant for the years after reuse. Figure 2-12 indicates this model’s estimate of potable water conserved. In the year 2000, the LEM model estimates that 102 gallons per capita-day (386 liters per capita-day) of potable water are saved. In the same year, the CCM method estimates a net savings of 69 gallons per capita-day. Figure 2-13 shows the comparison of the amount conserved using the 2 different methods.



How Using Potable Supplies to Supplement Reclaimed Water Flows can Increase Conservation, Hillsborough County, Florida

How Augmentation Can Help While peak season demand is what limits the number of customers a utility can connect, it is also short lived, lasting between 60 to 90 days. Augmenting reclaimed water supplies during this time of peak demand can allow a municipality to increase the number of customers served with reclaimed water while preserving the reliability (level of service) of the system. To illustrate this point, consider the Hillsborough County South/Central reclaimed water system. Reclaimed water supplies from the Falkenburg, Valrico, and South County Water Reclamation Facilities (WRFs) are expected to be an annual average of 12.67 mgd (555 l/s) in 2002. However, to avoid shortfalls in the peak demand season, the County will need to limit connections to an average annual demand of 7.34 mgd (321 l/s) or less. The County presently has a waiting list of customers that would demand an annual average of approximately 10.69 mgd (468 l/s). What if augmentation water were used to allow the County to connect these customers instead of making these customers wait? Water balance calculations indicate that from July through March, there will be more than enough reclaimed water to meet expected demands. However, in April, May, and June, reclaimed water demands will exceed available supplies and customers will experience shortages. Using a temporary augmentation supply of water could offset these shortages during this 60 to 90 day period.

Ensuring that an adequate source is available is one of the first steps in evaluating a potable water project. However, consideration of how many reclaimed water customers can be supplied by the flows from a water reclamation facility is seldom part of the reuse planning process. The problem with this approach has become apparent in recent years, as a number of large urban reuse systems have literally run out of water during peak reclaimed water demand times. In order to understand why this happens, it is important to understand the nature of demands for reclaimed water. Figure 2-14 illustrates expected seasonal reclaimed water demands for irrigation in southwest Florida. Every operator of a potable water system in this area expects demands to increase by 20 to 30 percent during April through June as customers use drinking water to meet peak season irrigation demands. For reclaimed water systems, which are dedicated to meeting urban irrigation demands, the peak season demands may increase by 50 to 100 percent of the average annual demand. It is, of course, the ability to meet these peak season demands that define the reliability of a utility system, including a reclaimed water system.

Figure 2-10.

Altamonte Springs Annual Potable Water Demands per Capita


Figure 2-11.

Estimated Potable Water Conserved Using Best LEM Method

Figure 2-12.

Estimated Potable Water Conserved Using the CCM Method


Figure 2-13.

Estimated Potable Water Conserved Using Both Method

Figure 2-14.

Estimated Raw Water Supply vs. Demand for the 2002 South/Central Service Area

Figure 2-14 illustrates the expected seasonal supply curve for 2002. The bottom curve shows the expected demand for the limited case where the County does not augment its water supplies. The top curve indicates how the County can meet current demand by augmenting its reclaimed water supply during April through June. The

limited reclaimed water system is constrained by peak seasonal demands (not exceeding supply) since customers expect year round service. For the system to meet all of the potential demands that have been identified, sufficient reclaimed water augmentation must be used to make up the differences in supply and demand.


The obvious question that must be answered is, “Can using supplemental water actually conserve water resources?” The answer is yes, to a point. The existing, limited reuse system serves an average annual demand of 7.34 mgd (321 l/s), conserving an annual average of 6.07 mgd (266 l/s) of potable water resources. This level of conservation is based on the County’s experiences with reductions in potable water demand after reclaimed water becomes available. In order to provide service to the entire 10.69 mgd (468 l/s) reclaimed water demand, the County will need an average annual supply of supplemental water of 0.5 mgd (22 l/s). For the purposes of this analysis, it is assumed this supplemental water comes from the potable water system and so is subtracted from the “Annual Average Potable Water Conserved.” This 0.5 mgd potable water supplemental supply increases the total volume of water conserved from 6.07 to 7.23 mgd (266 to 321 l/s). Therefore, 1.16 mgd (51 l/s) more potable water is conserved by using supplemental water. Therefore, an investment of 0.5 mgd (22 l/ s) of supplemental water allows the County to save 1.16 mgd (51 l/s) of potable water resources or, put another way, for each gallon (3.8 liters) of supplemental water used we realize a 2.32-gallon (8.8-liter) increase in water resources conserved. There are, of course, limitations to this practice. As more supplemental water is used, the amount of reclaimed water used (as a percentage of the total demand) decreases. Eventually, the supplemental water used will be equal to the water resources conserved. That is the break-even point. In this case potable water was used as the supplemental water, but in reality, other nonpotable supplies, such as raw groundwater, would likely be used. Short-term supplementation, such as that described above, is one of many tools that can be used by a reclaimed water provider to optimize its system. Utilities can also maximize their existing reclaimed water resources and increase efficiency by instituting Best Management Practices (BMPs). Examples of BMPs include individual metering, volume-based, water-conserving rate structures, planned interruption, peak season “interruptible service”, and time-of-day and day-of-week restrictions. When a reclaimed water provider is already experiencing either a long-term supply/demand imbalance or temporary drought effects, that provider should first use BMPs, before considering reclaimed water supplementation. Utilities should also investigate opportunities for enhanced reclaimed water storage capacity including innovative technological solutions, such as aquifer storage and recovery, and wet-weather discharge points that produce a net environmental benefit. Instituting BMPs and the other options mentioned can enable a reclaimed water utility to delay, lessen, or potentially eliminate the

need for augmentation of their reclaimed water system during peak reclaimed water demand periods.


Water Reclamation and Reuse Offer an Integrated Approach to Wastewater Treatment and Water Resources Issues in Phoenix, Arizona.

The rapidly developing area of North Phoenix is placing ever-increasing demands on the city’s existing wastewater collection system, wastewater treatment plants, and potable water resources. As an integrated solution to these issues, water reclamation and reuse have become an important part of Phoenix Water Services Department’s operational strategy. Cave Creek Reclaimed Water Reclamation Plant (CCWRP), in northeast Phoenix, began operation in September 2001. The facility uses an activated sludge nitrification/denitrification process along with filtration and ultraviolet light disinfection to produce a tertiary-grade effluent that meets the Arizona Department of Environmental Quality’s A+ standards. CCWRP is currently able to treat 8 mgd (350 l/s) and has an expansion capacity of 32 mgd (1,400 l/s). The Phoenix reclamation plant delivers reclaimed water through a nonpotable distribution system to golf courses, parks, schools, and cemeteries for irrigation purposes. The reclaimed water is sold to customers at 80 percent of the potable water rate. CCWRP’s sister facility, North Gateway Water Reclamation Plant (NGWRP), will serve the northwest portion of Phoenix. The design phase has been completed. The NGWRP will have an initial treatment capacity of 4 mgd (175 l/s) with an ultimate capacity of 32 mgd (1,400 l/s). The plant is modeled after the Cave Creek facility using the “don’t see it, don’t hear it, don’t smell it” design mantra. Construction will be preformed using the construction manager-at-risk delivery method. Phoenix is using geographic information system (GIS) technology to develop master plans for the buildout of the reclaimed water distribution system for both the Cave Creek and North Gateway reclamation plants. Through GIS, potential reclaimed water customers are easily identified. GIS also provides information useful for determining pipe routing, reservoir, and pump station locations. The goal is to interconnect the 2 facilities, thus building more reliability and flexibility into the system. The GIS model is dynamically linked to the water system, planning, and other important databases so that geospacial information is constantly kept up to date. A


hydraulic model is being used in conjunction with the GIS model to optimize system operation. Irrigation demand in Phoenix varies dramatically with the seasons, so groundwater recharge and recovery is a key component of the water reuse program. Phoenix is currently exploring the use of vadose zone wells because they do not require much space and are relatively inexpensive to construct. This method also provides additional treatment to the water as it percolates into the aquifer. A pilot vadose zone well facility has been constructed at the NGWRP site to determine the efficacy of this technology. A vadose zone recharge facility along with a recovery well is being designed for the CCWRP site. Nonpotable reuse and groundwater recharge with high quality effluent play an important role in the City’s water resources and operating strategies. The North Phoenix Reclaimed Water System (Figure 2-15) integrates multiple objectives, such as minimizing the impact of development in the existing wastewater infrastructure by treating wastewater locally and providing a new water resource in a desert environment. By using state-of-the-art technology, such as GIS, Phoenix will be able to plan the buildout of the reclaimed water system to maximize its efficiency and minimize costs.

(871 m3/d). The facility has a design capacity to reclaim up to 1.0 mgd (44 l/s). State standards require the use of treatment techniques for source control, oxidation, coagulation, filtration, and disinfection. Final reclaimed water requirements include a daily average turbidity of less than 2.0 NTU with no values above 5.0 NTU, total coliform less than 2.2 per 100 ml as a 7-day median value and total nitrogen below 10 mg/l. Major facility components include a septic tank effluent pumping (STEP) collection system, activated sludge biological treatment with nitrogen removal using Sequencing Batch Reactor (SBR) technology, flow equalization, an automated chemical feed system with in-line static mixers to coagulate remaining solids prior to filtration, a continuous backwash, upflow sand media filtration system, and chlorine disinfection. The facility also includes an on-line computer monitoring system. Process monitors provide continuous monitoring of flow, turbidity, and chlorine residual. Alarms provide warning when turbidity reaches 2.0 NTU, the flow to the filters shuts off at 3.0 NTU, and the intermediate pumps shut down at 3.5 NTU. Chlorine concentrations are set for an auto-dialer alarm if the flash mixer falls below 1.5 mg/l or if the final residual is below 0.75 mg/l. Only reclaimed water that meets the required standard is sent to upland use areas. Reclaimed water in Yelm is primarily used for seasonal urban landscape irrigation at local schools and churches, city parks, and a private residence along the distribution route. The true showcase of the Yelm project is Cochrane Memorial Park, an aesthetically pleasing 8acre city park featuring constructed surface and submerged wetlands designed to polish the reclaimed water prior to recharging groundwater. In the center of the park, a fishpond uses reclaimed water to raise and maintain stocked rainbow trout for catch and release. The City also uses reclaimed water for treatment plant equipment washdown and process water, fire fighting, street cleaning, and dust control. Although summers in western Washington are quite dry, during the winter rainy season there is not sufficient irrigation demand for reclaimed water. Excess water is sent to generate power in the Centralia Power Canal, a diversion from the Nisqually River. Based on state law, reclaimed water that meets both the reclamation standards and state and federal surface water quality requirements is “no longer considered a wastewater.” However, per their settlement agreement, Yelm is continuing to pursue the goal of 100 percent upland reuse via a program to add reclaimed water customers and uses. Yelm recently updated its Comprehensive Water Plan to emphasize an increased dependence on reclaimed water to replace potable water consumption to the greatest


Small and Growing Community: Yelm, Washington

The City of Yelm, Washington, a community of 3,500 residents, is considered one of western Washington’s fastest growing cities. In response to a determination from Thurston County that the continued use of septic systems in the Yelm area posed a risk to public health, the City developed a sewage plan. The original plan was to treat and discharge wastewater to the Nisqually River. However, the headwaters of the Nisqually River begin in Mount Rainier National Park and end in a National Wildlife Refuge before discharging into the Puget Sound Estuary. The river supports 5 species of Pacific salmon— chinook, coho, pink, chum, and steelhead—as well as sea-run cutthroat trout. Based on a settlement agreement with local environmental groups, the City agreed to pursue upland reuse of their Class A reclaimed water with the goal of eliminating the Nisqually River as a wastewater discharge location to augment surface water bodies only during times when reclaimed water could not be used 100 percent upland. Reclaimed water also plays a very important role in water conservation as Yelm has limited water resources. The reclamation plant went on line in August of 1999 and currently reclaims and reuses approximately 230,000 gpd


Figure 2-15.

North Phoenix Reclaimed Water System


extent possible. The City is constructing storage capacity to provide collection of reclaimed water during nonpeak periods for distribution during periods of peak demand. This will allow more efficient use of reclaimed water and eliminate the need for potable make-up water. Yelm is planning to use reclaimed water for bus washing, concrete manufacturing, and additional irrigation purposes. Sources: Washington State Department of Ecology and City of Yelm, 2003.


Landscape Uses of Reclaimed Water with Elevated Salinity: El Paso, Texas

(Table 2-13). Reclaimed water from the Hervey Plant has the lowest salinity (680 ppm), and a large portion of it is now being injected into an aquifer for recovery as potable water. Reclaimed water from the Haskell Plant and the Northwest plant have elevated levels of salinity, and are likely to be the principal reclaimed sources for irrigation from now into the near future. The cause of elevated salinity at the Northwest Plant is currently being investigated, and it appears to be related to intrusion of shallow saline groundwater into sewer collection systems located in the valley where high water tables prevail. Reuse of reclaimed water from the Hervey Plant on a golf course proceeded without any recognizable ill effects on turf or soil quality. This golf course is located on sandy soils developed to about 2 feet (60 cm) over a layer of caliche, which is mostly permeable. Broadleaf trees have experienced some foliar damage, but not to the extent of receiving frequent user complaints. This golf course uses low pressure, manual sprinklers, and plantings consist mostly of pines, which are spray resistant. Reuse of reclaimed water from the Northwest Plant, however, has caused severe foliar damage to a large number of broadleaf trees (Miyamoto and White, 2002). This damage has been more extensive than what was projected based on the total dissolved salts of 1200 ppm. However, this reclaimed water source has a Na concentration equal to or higher than saline reclaimed water sources in this part of the Southwest (Table 2-13). Foliar damage is caused primarily through direct salt adsorption through leaves. This damage can be minimized by reducing direct sprinkling onto the tree canopy. The use of low-trajectory nozzles or sprinklers was found to be

Because of declining reserves of fresh groundwater and an uncertain supply of surface water, the Public Service Board, the governing body of El Paso Water Utilities, has adopted a strategy to curtail irrigation use of potable water by substituting reclaimed municipal effluent. This strategy has been implemented in stages, starting with irrigation of a county-operated golf course using secondary effluent from the Haskell Plant, and a city-owned golf course with tertiary treated effluent from the Fred Hervey Plant. More recently, the reuse projects were expanded to use secondary effluent from the Northwest Plant to irrigate a private golf course, municipal parks, and school grounds (Ornelas and Brosman, 2002). Reclaimed water use from the Haskell Plant is also being expanded to include parks and school grounds. Salinity of reclaimed water ranges from 680 to 1200 ppm as total dissolved salts (TDS) depending on the plant

Table 2-13.

Average Discharge Rates and Quality of Municipal Reclaimed Effluent in El Paso and Other Area Communities
Reuse Area (acres) Water Quality TDS (ppm ) 680 980 1200 1800 1650 EC (dS m 1) 0.9 1.6 2.2 2.7 2.4 SAR Na (ppm ) 150 250 350 310 330 Cl (ppm ) 180 280 325 480 520 Soil Type

Plant Treatm ent Plants Capacity (m gd) El Paso Fred Hervey Haskell Northwest Alamogordo Odessa
1 2

10 27 17 ---

150 329 194 ---

3.7 7.3 11.0 2 1.9

Calciorthid, Aridisols Torrifluvent, Entisols Paleorthid, Aridisols Camborthid, Aridisols Paleustal, Alfisols



These water sources contain substantial quantities of Ca and SO4. Reclaimed water quality of this source changes with season.

Sources: Ornela and Brosman, 2002; Miyamoto and White, 2002; Ornelas and Miyamoto, 2003; and Miyamoto, 2003.


effective through a test program funded by the Bureau of Reclamation (Ornelas and Miyamoto, 2003). This finding is now used to contain salt-induced foliar damage. Another problem associated with the conversion to reclaimed water has been the sporadic occurrence of salt spots on the turf in areas where drainage is poor. This problem has been contained through trenching and subsoiling. Soil salinization problems were also noted in municipal parks and school grounds that were irrigated with potable water in the valley where clayey soils prevail. This problem is projected to increase upon conversion to reclaimed water from the Haskell Plant unless salt leaching is improved. The Texas A&M Research Center at El Paso has developed a guideline for soil selection (Miyamoto, 2003), and El Paso City Parks, in cooperation with Texas A&M Research Center, are initiating a test program to determine cost-effective methods of enhancing salt leaching. Current indications are that increased soil aerification activities, coupled with topdressing with sand, may prove to be an effective measure. If the current projection holds, reuse projects in El Paso are likely to achieve the primary goal, while demonstrating that reclaimed water with high Na and Cl concentrations (greater than 359 ppm) can be used effectively even in highly diverse soil conditions through site improvements and modified management practices.

any existing use of tertiary treated wastewater in fabric dyeing. General Dye and Finishing (General Dye) is a fabric dyeing facility located in Santa Fe Springs, California. This facility uses between 400 and 500 acre-feet per year (250 to 310 gpm) of water, primarily in their dye process and for boiler feed. CBMWD is working with the plant manager to convert the facility from domestic potable water to reclaimed water for these industrial purposes. A 1-day pilot test was conducted on October 15, 2002 using reclaimed water in one of the 12 large dye machines used at the facility. A temporary connection was made directly to the dye machine fill line using a 1-inch hose from an air release valve on the CBMWD reclaimed water system. General Dye conducted 2 tests with the reclaimed water, using reactive dye with a polycotton blend and using dispersed dye with a 100-percent polyester fabric. Both test loads used about 800 pounds of fabric with blue dyes. The identical means and methods of the dyeing process typically employed by General Dye with domestic water were also followed using reclaimed water. General Dye did not notice any difference in the dyeing process or quality of the end product using the reclaimed water versus domestic water. A 1-week demonstration test was conducted between November 20 and November 27, 2002, based on the successful results of the 1-day pilot test. A large variety of colors were used during the demonstration test. No other parameters were changed. Everything was done exactly the same with the reclaimed water that would have been done with the domestic water. As with the pilot test, the results indicated that reclaimed water can successfully be used in the fabric dyeing process, resulting in plans for a full conversion of the General Dye facility to reclaimed water for all process water needs.


Use of Reclaimed Water in a Fabric Dyeing Industry

The Central Basin Municipal Water District (CBMWD) reclaimed water system began operation in 1992 and currently serves approximately 3,700 acre-feet per year (2,300 gpm) for a variety of irrigation, commercial, and industrial uses. Industrial customers include the successful conversion of Tuftex Carpets in Santa Fe Springs, which was the first application in California of reclaimed water used for carpet dyeing. A significant benefit to using reclaimed water is the consistency of water quality. This reduces the adjustments required by the dye house that had previously been needed due to varying sources of water (e.g. Colorado River, State Water Project, or groundwater). Since completion of the initial system, CBMWD has continued to explore expansion possibilities, looking at innovative uses of reclaimed water. The fabric dyeing industry represents a significant potential for increased reclaimed water use in CBMWD and in the neighboring West Basin Municipal Water District (WBMWD). More than 15 dye houses are located within the 2 Districts, with a potential demand estimated to be greater than 4,000 acre-feet per year (2,500 gpm). A national search of reclaimed water uses did not identify


Survey of Power Plants Using Reclaimed Water for Cooling Water

A wide variety of power facilities throughout the U.S. were contacted and asked to report on their experience with the use of treated wastewater effluent as cooling water. Table 2-14 presents a tabulation of data obtained from contacts with various power facilities and related wastewater treatment plants that supply them with effluent water. Table 2-14 also provides a general summary of the treatment process for each WWTP and identifies treatment performed at the power plant.


Table 2-14.

Treatment Processes for Power Plant Cooling Water
Ave rage Cooling Wate r Supply & Re turn Flow (m gd) Supply = 0.65 Return = 0 Zero discharge; all blow -dow n evaporated or leaves plant in sludge. Was te w ate r Tre atm e nt Plant Proce s s e s Secondary treatment with Alum, Floc & Polymer; Additions settle solids, remove phosphorus Tre atm e nt for Cooling Wate r (by Pow e r Plant) Further treatment with clarification process, Flash Mix, Slow Mix. Also additions of ferric sulfate, polymer & sodium hypochlorite

Pow e r Facility & Location

1. Lancaster County Resource Recovery Facility Marietta, PA

2. PSE&G Ridgefield Park, NJ

Supply = 0.3 – 0.6 (make-up Water chemistry controlled supply to cooling towers) BlowSecondary Treatment, 85% down disposed of with plant with biocide, pH control, and minimum removal of solids wastewater to local sewer surfactant system. Supply = 0.7 (includes irrigation water) Blow-down of 0.093-mgd mixed with plant wastewater is returned to WWTP. Supply = 2.72 (annual avg.) to Clark Sta. Return = 0 Blow-down is discharged to holding ponds for evaporation Supply = 0.65 Cooling tower blow-down is discharged to a local sewage system and eventually returned to the WWTP. Advanced treatment with high level of disinfection. Partial tertiary treatment, removes phosphorus. Advanced Secondary treatment with nitrification, denitrification and biological phosphorus removal. Tertiary treatment through dual media filter & disinfection in chlorine contact tank. Primary & secondary settling. Biological nutrient removal, with post filtration via sand filters. Chlorine addition, biocide, surfactant, tri-sodium phosphate, pH control with sulfuric acid.

3. Hillsborough County Solid Waste to Energy Recovery Facility (operated by O gden Martin Corp.) Tampa, FL

4. Nevada Power – Clark and Sunrise Stations Las Vegas, NV

None at present time. Previously treated with lime & softener; discontinued 2-3 years ago.

5. Panda Brandywine Facility Brandywine, MD

Addition of corrosion inhibitors, sodium hypochlorite, acid for pH control, and anti-foaming agents.

6. Chevron Refineries; El Segundo, CA Approx = 3-5 Richmond, CA Return = 0

Tertiary treatment El Segundo: Ammonia Stripping plant across Richmond Plant uses Nalco street. Chemical for further Richmond: Caustic Soda treatment. Treatment Plant Specifically for Chevron. Advanced Wastewater treatment including filtration, disinfection & biological nutrient removal to within 5:5:3:1* PH adjustment with acid, addition of scale inhibitors and chlorine. Control of calcium level. All chemical adjustments done at cooling towers.

7. Curtis Stanton Energy Center O range County, FL (near O rlando)

Supply = 10 Return = 0 Blow-down is evaporated in brine concentrator and crystallizer units at power plant for zero discharge.

8. Palo Verde Nuclear Plant Phoenix, AZ

Tertiary treatment plant consisting of trickling filters WWTPs provide secondary for ammonia removal, 1s t and Total Supply to (3) units = 72 treatment. Treated effluent 2 nd stage clarifiers for not transmitted to Palo Return = 0 removal of phosphorus, Zero discharge facility; all blow- Verde is discharged to magnesium, and silica. riverbeds (wetlands) under Cooling tower water is down is evaporated in ponds. State of Arizona permits. further controlled by addition of dispersants, defoaming agents, and sodium

* 5:5:3:1 refers to constituent limits of 5 mg/l BOD, 5 mg/l TSS, 3 mg/l nitrogen and 1 mg/l phosphorus. Source: DeStefano, 2000 59

It is important to note that, in all cases for the facilities contacted, the quality of wastewater treatment at each WWTP is governed by the receiving water body where the treated effluent is discharged, and its classification. For example, if the water body serves as a source of drinking water or is an important fishery, any treated effluent discharged into it would have to be of high quality. Effluent discharged to an urban river or to the ocean could be of lower quality.

Major crops produced include corn, soybeans, coastal Bermuda grass, and rye. Corn is stored as high-moisture grain prior to sale, and soybeans are sold upon harvest. Both the rye and Bermuda grass are grazed by cattle. Some of the Bermuda grass is harvested as hay and haylage. Cows are allows to graze in winter.



Agricultural Reuse in Tallahassee, Florida

Spray Irrigation at Durbin Creek WWTP Western Carolina Regional Sewer Authority

The Tallahassee agricultural reuse system is a cooperative operation where the city owns and maintains the irrigation system, while the farming service is under contract to commercial enterprise. During the evolution of the system since 1966, extensive evaluation and operational flexibility have been key factors in its success. The City of Tallahassee was one of the first cities in Florida to use reclaimed water for agricultural purposes. In 1966, the City began to use reclaimed water from its secondary wastewater treatment plant for spray irrigation. In 1971, detailed studies showed that the system was successful in producing crops for agricultural use. The studies also concluded that the soil was effective at removing SS, BOD, bacteria, and phosphorus from the reclaimed water. Until 1980, the system was limited to irrigation of 120 acres (50 hectares) of land used for hay production. Based upon success of the early studies and experience, a new spray field was constructed in 1980, southeast of Tallahassee. The southeast spray field has been expanded 3 times since 1980, increasing its total area to approximately 2100 acres (840 hectares). The permitted application rate of the site is 3.16 inches per week (8 cm per week), for a total capacity of 24.5 mgd (1073 l/s). Sandy soils account for the high application rate. The soil composition is about 95 percent sand, with an interspersed clay layer at a depth of approximately 33 feet (10 meters). The spray field has gently rolling topography with surface elevations ranging from 20 to 70 feet (6 to 21 meters) above sea level. Secondary treatment is provided to the City’s Thomas P. Smith wastewater reclamation plant and the Lake Bradford Road wastewater reclamation plant. The reclaimed water produced by these wastewater reclamation plants meet water quality requirements of 20 mg/l for BOD and TSS, and 200/100 ml for fecal coliform. Reclaimed water is pumped approximately 8.5 miles (13.7 km) from the treatment plant to the spray field and distributed via 16 center-pivot irrigation units.

The Durbin Creek Wastewater Treatment Facility, located near Fountain Inn, South Carolina, is operated by the Western Carolina Regional Sewer Authority (WCRSA). The plant discharges to Durbin Creek, a relatively small tributary of the Enoree River. Average flow from the Durbin Creek Plant is 1.37 mgd (5.2 x 103 m3/day) with a peak flow of 6.0 mgd (22.7 x 103 m3/day) during storm events. The plant is permitted for an average flow of 3.3 mgd (12.5 x 103 m3/day). The Durbin Creek plant is located on an 200-acre (81hectare) site. Half of the site is wooded with the remaining half cleared for land application of biosolids. Hay is harvested in the application fields. Much of the land surrounding the plant site is used as a pasture and for hay production without the benefit of biosolids applications. As a result of increasingly stringent NPDES permit limits and the limited assimilative capacity of the receiving stream, WCRSA began a program to eliminate surface water discharge at this facility. Commencing in 1995, WCRSA undertook a detailed evaluation of land application and reuse at Durbin Creek. The initial evaluation focused on controlling ammonia discharged to the receiving stream by combining agricultural irrigation with a hydrograph-controlled discharge strategy. In order to appreciate the potential for reuse and land application to address current permit issues facing the Durbin Creek WWTP, a brief discussion of their origin is necessary. South Carolina develops waste load allocations calculated by a model that is based on EPA discharge criteria. Model inputs include stream flow, background concentrations of ammonia, discharge volume, water temperature, pH, and whether or not salmonids are present. Because water temperature is part of the model input, a summer (May through October) and a winter (November through April) season are recognized in the current NPDES permit. Ammonia concentrations associated with both acute and chronic toxicity are part of the model output. The stream flow used in the model is the estimated 7-day, 10-year low flow event (7Q10). For the receiving stream, the 7Q10 value is 2.9 cfs (0.08 m3/s).


The permitted flow of 3.3 mgd (12.5 x 103 m3/day) is used as the discharge volume in the model. A detailed evaluation of the characteristics of the receiving water body flow was required to evaluate the potential of reuse to address the proposed NPDES limits. The probability of occurrence of a given 7-day low flow rate was then determined using an appropriate probability distribution. The annual summer and winter 7Q10 flows for the Durbin Creek site were then estimated with the following results: Annual Summer Winter 7Q10 2.9 cfs (0.08 m3/s) 7Q10 (May through October) 2.9 cfs (0.08 m3/s) 7Q10 (November through April) 6.4 cfs (0.18 m3/s)

The next step was to evaluate various methods of diverting or withholding a portion of the design discharge flow under certain stream flow conditions. The most prominent agricultural enterprise in the vicinity of the Durbin Creek WWTP is hay production. Thus, WCRSA decided to investigate agricultural reuse as its first alternative disposal method. To evaluate how irrigation demands might vary over the summer season, a daily water balance was developed to calculate irrigation demands. The irrigation water balance was intended to calculate the consumptive need of an agricultural crop as opposed to hydraulic capacities of a given site. This provision was made because farmers who would potentially receive reclaimed water in the future would be interested in optimizing hay production and could tolerate excess irrigation as a means of disposal. Results of this irrigation water balance were then combined with the expected stream flow to evaluate the requirements of integrating agricultural irrigation with a hydrograph control strategy. The results of this analysis are provided in Figure 2-16, which indicates the storage volume required as a function of the irrigated area given a design flow of 3.3 mgd (12.5 x 103 m3/day). As shown in Figure 2-16, if no irrigated area is provided, a storage volume of approximately 240 million gallons (900 x 103 m3) would be required to

The predicted annual 7Q10 of 2.9 cfs (0.08 m3/s) matched the value used by the state regulatory agency and confirmed the validity of the analysis. The winter 7Q10 was found to be more than double that of the summer 7Q10. This information was then used in conjunction with the state’s ammonia toxicity model to develop a conceptual summer and winter discharge permit for effluent discharge based on stream flow.

Figure 2-16.

Durbin Creek Storage Requirements as a Function of Irrigated Area


achieve compliance with a streamflow dependent permit. This storage volume decreases dramatically to approximately 50 million gallons (190 x 103 m3) if 500 acres (200 hectares) of irrigated area are developed. As irrigated area increases from 500 to 1,200 acres (200 to 490 hectares), the corresponding ratio of increased irrigated area to reduction in storage is less. As indicated in Figure 2-16, storage could hypothetically be completely eliminated given an irrigated area of approximately 1,900 acres (770 hectares). The mathematical modeling of stream flows and potential demands has demonstrated that reuse is a feasible means of achieving compliance with increasingly stringent NPDES requirements in South Carolina.

or on samples of crops grown with the reclaimed water. No tendency was found for metals to accumulate in soils or on plant tissues. Soil permeability was not impaired. By the time the study was completed in 1987, the project had gained widespread community support for water reclamation. As a result of the MWRSA, a water reclamation plant and distribution system were completed in 1997. The project was designed to serve 12,000 acres (4,850 hectares) of artichokes, lettuce, cauliflower, broccoli, celery, and strawberries. Delivery of reclaimed water was delayed until spring of 1998 to address new concerns about emerging pathogens. The reclaimed water was tested for E. Coli 0157:H7, Legionella , Salmonella , Giardia , Cryptosporidium, and Cyclospora. No viable organisms were found and the results were published in the Recycled Water Food Safety Study. This study increased grower and buyer confidence. Currently, 95 percent of the project acreage is voluntarily using reclaimed water. Growers felt strongly that health department regulations should be minimal regarding use of reclaimed water. The MRWPCA succeeded in getting the County Health Department to approve wording requirements for signs along public roads through the project to say, “No Trespassing,” rather than previously proposed wording that was detrimental to public acceptance of reclaimed water. Similarly, field worker safety training requires only that workers not drink the water, and that they wash their hands before eating or smoking after working with reclaimed water. Three concerns remain: safety, water quality, and long term soil health. To address safety, pathogen testing continues and results are routinely placed on the MRWPCA website at The water quality concern is partly due to chloride, but mostly due to sodium concentration levels. MRWPCA works with sewer users to voluntarily reduce salt levels by using more efficient water softeners, and by changing from sodium chloride to potassium chloride for softener regeneration. In 1999, the agency began a program of sampling soils from 3 different depth ranges 3 times each season from 4 control sites (using well water) and 9 test sites (using reclaimed water). Preliminary results indicate that using reclaimed water for vegetable production is not causing the soil to become saline.


Agricultural Irrigation of Vegetable Crops: Monterey, California

Agriculture in Monterey County, located in the central coastal area of California, is a $3 billion per year business. The northern part of the county produces a variety of vegetable crops, many of which may be consumed raw. As far back as the 1940s, residential, commercial, industrial, and agricultural users were overdrawing the County’s northern groundwater supply. This overdraw lowered the water tables and created an increasing problem of saltwater intrusion. In the mid-1970s, the California Central Coast Regional Water Quality Control Board completed a water quality management plan for the area, recommending reclaimed water for crop irrigation. At that time, agricultural irrigation of vegetable crops with reclaimed water was not widely accepted. To respond to questions and concerns from the agricultural community, the Monterey Regional Water Pollution Control Agency (MRWPCA) sponsored an 11-year, $7-million pilot and demonstration project known as the Monterey Wastewater Reclamation Study for Agriculture (MWRSA). Study objectives were to find answers to questions about such issues as virus and bacteria survival on crops, soil permeability, and yield and quality of crops, as well as to provide a demonstration of field operations for farmers who would use reclaimed water. Five years of field operations were conducted, irrigating crops with 2 types of tertiary treated wastewater, with a well water control for comparison. Artichokes, broccoli, cauliflower, celery, and several varieties of lettuce were grown on test plots and a demonstration field. Crops produced with reclaimed water were healthy and vigorous, and the system operated without complications. The results of the study provided evidence that using reclaimed water can be as safe as irrigating with well water, and that large scale water reclamation can be accomplished. No virus was found in reclaimed water used for irrigation


Water Conserv II: City of Orlando and Orange County, Florida

As a result of a court decision in 1979, the City of Orlando and Orange County, Florida, were mandated to cease discharge of their effluent into Shingle Creek, which


flows into Lake Tohopekaliga, by March 1988. The City and County immediately joined forces to find the best and most cost-effective solution. Following several rounds of extensive research, the decision was made to construct a reuse project in West Orange and Southeast Lake counties along a high, dry, and sandy area known as the Lake Wales Ridge. The project was named Water Conserv II. The primary use of the reclaimed water would be for agricultural irrigation. Daily flows not needed for irrigation would be distributed into rapid infiltration basins (RIBs) for recharge of the Floridan aquifer. Water Conserv II is the largest reuse project of its type in the world, a combination of agricultural irrigation and RIBs. It is also the first reuse project in Florida permitted by the Florida Department of Environmental Protection to irrigate crops produced for human consumption with reclaimed water. The project is best described as “a cooperative reuse project by the City of Orlando, Orange County, and the agricultural community.” The City and County jointly own Water Conserv II. The project is designed for average flows of 50 mgd (2,190 l/s) and can handle peak flows of 75 mgd (3,285 l/s). Approximately 60 percent of the daily flows are used for irrigation, and the remaining ±40 percent is discharged to the RIBs for recharge of the Floridan aquifer. Water Conserv II began operation on December 1, 1986. At first, citrus growers were reluctant to sign up for reclaimed water. They were afraid of potential damage to their crops and land from the use of the reclaimed water. The City and County hired Dr. Robert C.J. Koo, a citrus irrigation expert at the University of Florida’s Citrus Research Center at Lake Alfred, to study the use of reclaimed water as an irrigation source for citrus. Dr. Koo concluded that reclaimed water would be an excellent source of irrigation water for citrus. The growers were satisfied and comfortable with Dr. Koo’s findings, but wanted long-term research done to ensure that there would be no detrimental effects to the crop or land from the long-term use of reclaimed water. The City and County agreed, and the Mid Florida Citrus Foundation (MFCF) was created. The MFCF is a non-profit organization conducting research on citrus and deciduous fruit and nut crops. All research is conducted by faculty from the University of Florida’s Institute of Food and Agricultural Sciences (IFAS). The MFCF Board of Directors is comprised of citrus growers in north central Florida and representatives from the City of Orlando, Orange County, the University of Florida IFAS, and various support industries. Goals of the MFCF are to develop management practices that will allow growers in the northern citrus area to re-establish citrus and grow

it profitably, provide a safe and clean environment, find solutions to challenges facing citrus growers, and promote urban and rural cooperation. All research conducted by the MFCF is located within the Water Conserv II service area. Reclaimed water is used on 163 of the 168 acres of research. MFCF research work began in 1987. Research results to date have been positive. The benefits of irrigating with reclaimed water have been consistently demonstrated through research since 1987. Citrus on ridge (sandy, well drained) soils respond well to irrigation with reclaimed water. No significant problems have resulted from the use of reclaimed water. Tree condition and size, crop size, and soil and leaf mineral aspects of citrus trees irrigated with reclaimed water are typically as good as, if not better than, groves irrigated with well water. Fruit quality from groves irrigated with reclaimed water was similar to groves irrigated with well water. The levels of boron and phosphorous required in the soil for good citrus production are present in adequate amounts in reclaimed water. Thus, boron and phosphorous can be eliminated from the fertilizer program. Reclaimed water maintains soil pH within the recommended range; therefore, lime no longer needs to be applied. Citrus growers participating in Water Conserv II benefit from using reclaimed water. Citrus produced for fresh fruit or processing can be irrigated by using a direct contact method. Growers are provided reclaimed water 24 hours per day, 7 days per week at pressures suitable for micro-sprinkler or impact sprinkler irrigation. At present, local water management districts have issued no restrictions for the use of reclaimed water for irrigation of citrus. By providing reclaimed water at pressures suitable for irrigation, costs for the installation, operation, and maintenance of a pumping system can be eliminated. This means a savings of $128.50 per acre per year ($317 per hectare per year). Citrus growers have also realized increased crop yields of 10 to 30 percent and increased tree growth of up to 400 percent. The increases are not due to the reclaimed water itself, but the availability of the water in the soil for the tree to absorb. Growers are maintaining higher soil moisture levels. Citrus growers also benefit from enhanced freeze protection capabilities. The project is able to supply enough water to each grower to protect his or her entire production area. Freeze flows are more than 8 times higher than normal daily flows. It is very costly to the City and County to provide these flows (operating costs average $15,000 to $20,000 per night of operation), but they feel it is well worth the cost. If growers were to be frozen out, the project would lose its customer base. Sources of water to meet freeze flow demands include normal daily flows of 30 to 35 mgd (1,310 to 1,530 l/s), 38 million


gallons of stored water (143,850 m3), 80 mgd (3,500 l/s) from twenty-five 16-inch diameter wells, and, if needed, 20 mgd (880 l/s) of potable water from the Orlando Utilities Commission. Water Conserv II is a success story. University of Florida researchers and extension personnel are delighted with research results to date. Citrus growers sing the praises of reclaimed water irrigation. The Floridan aquifer is being protected and recharged. Area residents view the project as a friendly neighbor and protector of the rural country atmosphere.


The Creation of a Wetlands Park: Petaluma, California

A plan has been developed to connect the 2 parcels via trails for viewing the tidal marsh, the polishing wetlands, and the riparian/creek area. The plan also calls for restoration and expansion of the riparian zone, planting of native vegetation, and restoration/enhancement of the tidal marsh. The polishing wetlands will be constructed on a portion of the 133 acres (54 hectares) of uplands. The remainder of the upland areas will either be restored for habitat or cultivated as a standing crop for butterfly and bird foraging. Landscaping on the wetlands site will be irrigated with reclaimed water. A renowned environmental artist developed the conceptual plan with an image of the dog-faced butterfly formed by the wetland cells and trails. Funding for acquisition of the land and construction of the trails and restoration projects has been secured from the local (Sonoma County) open space district and the California Coastal Conservancy in the amount of $4 million. The citizen’s alliance has continued to promote the concept. The alliance recently hosted a tour of the site with the National Audubon Society, asking that the site be considered for the location of an Audubon Interpretive Center.

The City of Petaluma, California, has embarked on a project to construct a new water reclamation facility. The existing wastewater plant was originally built in 1938, and then upgraded over the years to include oxidation ponds for storage during non-discharge periods. The city currently uses pond effluent to irrigate 800 acres (320 hectares) of agricultural lands and a golf course. As part of the new facility, wetlands are being constructed for multiple purposes including treatment (to reduce suspended solids, metals, and organics), reuse, wildlife habitat, and public education and recreation. The citizens of Petaluma have expressed a strong interest in creating a facility that not only provides wastewater treatment and reuse, but also serves as a community asset. In an effort to further this endeavor, the citizens formed an organization called the Petaluma Wetlands Park Alliance. Currently, the project is being designed to include 30 acres (12 hectares) of vegetated wetlands to remove algae. The wetlands will be located downstream from the City’s oxidation ponds. The vegetated treatment wetlands will not be accessible to the general public for security reasons. However, an additional 30 acres (12 hectares) of polishing wetlands with both open water and dense vegetation zones will be constructed on an adjacent parcel of land. These polishing wetlands will be fed by disinfected water from the treatment wetlands, so public access will be allowed. Berms around all 3 wetland cells will provide access trails. The parcel of land where the polishing wetlands will be constructed has many interesting and unique features. An existing creek and riparian zone extend through the upland portion of the parcel down to the Petaluma River. The parcel was historically farmed all the way to the river, but in an El Nino event, the river levees breached and 132 acres (53 hectares) of land has been returned to tidal mudflat/marsh. The parcel is directly adjacent to a city park, with trails surrounding ponds for dredge spoils.


Geysers Recharge Project: Santa Rosa, California

The cities of central Sonoma County, California, have been growing rapidly, while at the same time regulations governing water reuse and discharge have become more stringent. This has taxed traditional means of reusing water generated at the Laguna Wastewater Plant and Reclamation Facility. Since the early 1960s, the Santa Rosa Subregional Water Reclamation System has provided reclaimed water for agricultural irrigation in the Santa Rosa Plain, primarily to forage crops for dairy farms. In the early 1990s, urban irrigation uses were added at Sonoma State University, golf courses, and local parks. The remaining reclaimed water not used for irrigation was discharged to the Laguna de Santa Rosa from October through May. But limited storage capacity, conversion of dairy farms to vineyards (decreasing reclaimed water use by over two-thirds), and growing concerns over water quality impacts in the Laguna de Santa Rosa, pressured the system to search for a new and reliable means of reuse. In the northwest quadrant of Sonoma County lies the Geysers Geothermal Steamfield, a super-heated steam resource used to generate electricity since the mid 1960s. At its peak in 1987, the field produced almost 2,000 megawatts (MW), enough electricity to supply an estimated 2 million homes and businesses with power. Geysers operators have mined the underground steam to such


a degree over the years that electricity production has declined to about 1,200 MW. As a result, the operators are seeking a source of water to recharge the deep aquifers that yield steam. Geothermal energy is priced competitively with fossil fuel and hydroelectric sources, and is an important “green” source of electricity. In 1997, a neighboring sewage treatment district in Lake County successfully implemented a project to send 8 mgd (350 l/s) of secondary-treated water augmented with Clear Lake water to the southeast Geysers steamfields for recharge. In 1998, the Santa Rosa Subregional Reclamation System decided to build a conveyance system to send 11 mgd (480 l/s) of tertiary-treated water to the northwest Geysers steamfield for recharge. The Santa Rosa contribution to the steamfield is expected to yield an additional 85 MW or more of electricity production. The conveyance system to deliver water to the steamfield includes 40 miles (64 km) of pipeline, 4 large pump stations, and a storage tank. The system requires a lift of 3,300 feet (1,005 meters). Distribution facilities within the steamfield include another 18 miles (29 km) of pipeline, a pump station, and tank, plus conversion of geothermal wells from production wells to injection wells. The contract with the primary steamfield operator, Calpine Corporation, states that Calpine is responsible for the construction and operation of the steamfield distribution system and must provide the power to pump the water to the steamfield. The Subregional Reclamation System, in turn, is responsible for the construction and operation of the conveyance system to the steamfield and provides the reclaimed water at no charge. The term of the contract is for 20 years with an option for either party to extend for another 10 years. One of the major benefits of the Geysers Recharge Project is the flexibility afforded by year-round reuse of water. The system has been severely limited because of seasonal discharge constraints and the fact that agricultural reuse is not feasible during the wet winter months. The Geysers steamfield will use reclaimed water in the winter, when no other reuse options are available. However, during summer months, demand for reuse water for irrigation is high. The system will continue to serve agricultural and urban users while maintaining a steady but reduced flow of reclaimed water to the Geysers. A detailed daily water balance model was constructed to assist in the design of the initial system and to manage the optimum blend of agricultural, urban, and Geysers recharge uses. In addition to the benefits of power generation, the Geysers Recharge Project will bring an opportunity for agricultural reuse along the Geysers pipeline alignment,

which traverses much of Sonoma County’s grape-growing regions. Recent listings of coho salmon and steelhead trout as threatened species may mean that existing agricultural diversions of surface waters will have to be curtailed. The Geysers pipeline could provide another source of water to replace surface water sources, thereby preserving the habitat of the threatened species.


Advanced Wastewater Reclamation in California

The Groundwater Replenishment (GWR) System is a regional water supply project sponsored jointly by the Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD) in southern California. Planning between OCWD and OCSD eventually led to the decision to replace Water Factory 21 (WF21) with the GWR System. OCSD, an early partner with OCWD in WF21, will continue to supply secondary wastewater to the GWR System. As one of the largest advanced reclaimed water facilities in the world, the GWR System will protect the groundwater from further degradation due to seawater intrusion and supplement existing water supplies by providing a new, reliable, high-quality source of water to recharge the Orange County groundwater basin. For OCSD, reusing the water will also provide peak wastewater flow disposal relief and postpone the need to construct a new ocean outfall by diverting treated wastewater flows that would otherwise be discharged to the Pacific Ocean. The GWR System addresses both water supply and wastewater management needs through beneficial reuse of highly treated wastewater. OCWD is the local agency responsible for managing and protecting the lower Santa Ana River groundwater basin. Water supply needs include both the quantity and quality of water. The GWR System offers a new source of water to meet future increasing demands from the region’s groundwater producers, provides a reliable water supply in times of drought, and reduces the area’s dependence on imported water. The GWR System will take treated secondary wastewater from OCSD (activated sludge and trickling filter effluent) and purify it using microfiltration (MF), reverse osmosis (RO) and ultraviolet (UV) disinfection. Lime is added to stabilize the water. This low-salinity water (less than 100 mg/l TDS) will be injected into the seawater barrier or percolated through the ground into Orange County’s aquifers, where it will blend with groundwater from other sources, including imported and Santa Ana River stormwater, to improve the water quality. The GWR System will produce a peak daily production capacity of 78,400 acre-feet per year (70 mgd or 26,500 m3/yr) in the initial phase and will ultimately produce nearly 145,600 acre-


feet per year (130 mgd or 492,100 m3/yr) of a new, reliable, safe drinking water supply, enough to serve over 200,000 families. Over time, the water produced by the GWR System will lower the salinity of groundwater by replacing the high-TDS water currently percolated into the groundwater basin with low-TDS reclaimed water from the GWR System. The project conforms to the California State Constitution by acknowledging the value of reclaimed water. Less energy is used to produce the GWR System water than would be required to import an equivalent volume of water, reducing overall electrical power demand in the region. The GWR System will also expand the existing seawater intrusion barrier to protect the Orange County groundwater basin from further degradation. The groundwater levels have been lowered significantly in some areas of the groundwater basin due to the substantial coastal pumping required to meet peak summer potable water demands. The objective of the barrier is to create a continuous mound of freshwater that is higher than sea level, so that the seawater cannot migrate into the aquifer. As groundwater pumping activities increase, so do the amounts of freshwater required to maintain the protective mound. OCWD currently operates 26 injection wells to supply water to the barrier first created in the mid 1970s. Additional water is required to maintain a suitable barrier. To determine optimal injection well capacities and locations, a Talbert Gap groundwater computer model was constructed and calibrated for use as a predictive tool. Based on the modeling analysis, 4 new barrier wells will be constructed in an alignment along the Santa Ana River to cut off saltwater intrusion at the east end of the Talbert Gap. The modeling results also indicate that a western extension of the existing barrier is required. Twelve new barrier wells will be constructed at the western end of the Talbert Gap to inhibit saltwater intrusion under the Huntington Beach mesa. The project benefits OCSD’s wastewater management effort as well as helping to meet Orange County’s water supply requirements. The GWR System conforms to the OCSD Charter, which supports water reuse as a scarce natural resource. By diverting peak wastewater effluent discharges, the need to construct a new ocean outfall is deferred, saving OCSD over $175 million in potential construction costs. These savings will be used to help off-set the cost of the GWR system where OCSD will pay for half of the Phase 1 construction. The GWR System also reduces the frequency of emergency discharges near the shore, which are a significant environmental issue with the local beach communities.


An Investigation of Soil Aquifer Treatment for Sustainable Water

An intensive study, entitled, “An Investigation of Soil Aquifer Treatment for Sustainable Water Reuse,” was conducted to assess the sustainability of several different SAT systems with different site characteristics and effluent pretreatments (AWWARF, 2001). The sites selected for study and key characteristics of the sites are presented in Table 2-15. Main objectives of the study were to: (1) examine the sustainability of SAT systems leading to indirect potable reuse of reclaimed water; (2) characterize the processes that contribute to removal of organics, nitrogen, and viruses during transport through the infiltration interface, soil percolation zone, and underlying groundwater aquifer; and (3) develop relationships among above-ground treatment and SAT for use by regulators and utilities. The study reported the following results:
„ Dissolved organic carbon (DOC) present in SAT prod-

uct water was composed of natural organic matter (NOM), soluble microbial products that resemble NOM, and trace organics.

Characterization of the DOC in SAT product water determined that the majority of organics present were not of anthropenic origin. The frequency of pathogen detection in SAT products waters could not be distinguished from the frequency of pathogen detection in other groundwaters. Nitrogen removal during SAT was sustained by anaerobic ammonia oxidation.



The study reported the following impacts:

Effluent pretreatment did not affect final SAT product water with respect to organic carbon concentrations. A watershed approach may be used to predict SAT product water quality. Removal of organics occurred under saturated anoxic conditions and a vadose zone was not necessary for an SAT system. If nitrogen removal is desired during SAT, nitrogen must be applied in a reduced form, and a vadose zone combined with soils that can exchange ammonium ions is required.



Table 2-15.

Field Sites for Wetlands/SAT Research
Facility Key Site Characteristics Deep vadose zone (>100 feet) with extensive vadose zone monitoring capabilities and several shallow groundwater wells located downgradient. Shallow vadose zone (5-20 feet). Multi-depth sampling capabilities below basins. Array of shallow groundwater wells located from 500 feet to greater than 10,000 feet from recharge site. Horizontal flow and shallow (<21 feet) saturated zone sampling capabilities. Majority of flow infiltrates into groundwater. Vadose zone (20-50 feet). Water supply is a mixture of reclaimed water and other available water sources. Multi-depth sampling capabilities. Shallow vadose zone (10-20 feet). Water supply is a mixture of reclaimed water and other available water sources. Multi-depth sampling capabilities. Horizontal flow and shallow (<3 feet) vadose zone sampling capabilities. Approximately 25% of flow infiltrates into groundwater. Deep vadose zone (>100 feet). Multi-depth and downgradient sampling capabilities exist. Wastewater treatment applied is similar to facilities in Mesa and Phoenix, Arizona. However, drinking water supply is based only on local groundwater.

Sweetwater Wetlands/Recharge Facility, AZ

Mesa Northwest, AZ Phoenix Tres Rios Cobble Site, AZ Rio Hondo/Montebello Forebay, CA

San Gabriel/Montebello Forebay, CA Riverside Water Quality Control Plant Hidden Valley Wetlands, CA East Valley (Hansen Spreading Grounds), CA Avra Valley Wastewater Treatment Facility, AZ

„ The distribution of disinfection by-products produced

during chlorination of SAT product water was affected by elevated bromide concentrations in reclaimed water.


The City of West Palm Beach, Florida Wetlands-Based Water Reclamation Project

The City of West Palm Beach water supply system consists of a 20-square-mile (52-km2) water catchment area and surface water allocation from Lake Okeechobee, which flows to a canal network that eventually terminates at Clear Lake, where the City’s water treatment plant is located. As part of the Everglades restoration program, the timing, location, and quantity of water releases to the South Florida Water Management District (SFWMD) canals from Lake Okechobee will be modified. More water will be directed towards the Everglades for hydropattern restoration and less water will be sent to the SFWMD canals. This translates into less water available for water supplies in the lower east coast area. Therefore, indirect potable reuse, reuse for aquifer recharge purposes, and aquifer storage and recovery are some of the alternative water supply strategies planned by the City of West Palm Beach.

The City of West Palm Beach has developed a program to use highly treated wastewater from their East Central Regional Wastewater Treatment Plant (ECRWWTP) for beneficial reuse including augmentation of their drinking water supply. Presently, all of the wastewater effluent from the ECRWWTP (approximately 35 mgd [1,530 l/s] average daily flow) is injected over 3,000 feet (914 meters) into the groundwater (boulder zone) using 6 deep wells. Rather than continuing to dispose of the wastewater effluent, the City of West Palm Beach developed the Wetlands-Based Water Reclamation Project (WBWRP). The project flow path is shown in Figure 2-17. To protect and preserve its surface water supply system and to develop this reuse system to augment the water supply, the City purchased a 1,500-acre (607-hectare) wetland reuse site. This site consists of a combination of wetlands and uplands. A portion of this property was used for the construction of a standby wellfield. The standby wellfield site covers an area of 323 acres (131 hectares) and consists of wetlands and uplands dominated by Melaleuca trees. Two important goals of the project were to: (1) develop an advanced wastewater treatment facility at the ECRWWTP that could produce reclaimed water that, when discharged, would be compatible with the hydrology and water quality at the wetland


reuse site, and (2) produce a reliable water supply to augment the City’s surface water supply. Treatment was to be provided by the reclaimed water production facility, wetlands, and through aquifer recharge. Groundwater withdrawal would meet drinking water and public health standards. Monitoring was performed at the wetland reuse site from July 1996 to August 1997. The purpose of this monitoring was to establish baseline conditions in the wetlands prior to reclaimed water application and to determine the appropriate quality of the reclaimed water that will be applied to the wetland reuse site. In addition to the monitoring of background hydrology, groundwater quality, and surface water quality, the baseline-monitoring program investigated sediment quality, vegetation, fish, and the presence of listed threatened and endangered plant and animal species. Groundwater samples from the wetland reuse site and the standby wellfield met the requirements for drinking water except for iron. Iron was detected in excess of the secondary drinking water standards of 0.3 mg/l at all of the wells, but not in excess of the Class III surface water quality criteria of 1.0 mg/l. Total nitrogen (TN) concentrations in the wetlands ranged from 0.67 mg/l to 3.85 mg/l with an average value of 1.36 mg/l. The concentration of total phosphorus (TP) was low throughout the wetlands, ranging from less than 0.01 to 0.13 mg/l, with an average value of 0.027 mg/l. In 1995, the City of West Palm Beach constructed a 150,000-gpd (6.6-l/s) AWT constructed wetlands demonstration project. The goals of this project were to demonstrate that an AWT facility could produce an effluent quality of total suspended solids (TSS), 5-day carbonaceous Figure 2-17. Project Flow Path

biochemical oxygen demand (CBOD5), TN, and TP goals of 5, 5, 3, and 1 mg/l, respectively, and that wetlands could provide some additional treatment prior to discharge. The demonstration facility met the AWT goals as well as all of the surface water quality standards, state and federal drinking water standards (except for iron), and all public health standards (absence of Cryptosporidum, Giardia, enteric viruses, and coliforms). A hydrologic model capable of simulating both groundwater flow and overland flow was constructed and calibrated to assess the hydrology, hydrogeology, and potential hydraulic conveyance characteristics within the project area. The model indicated that maintenance of viable wetlands (i.e., no extended wet or dry periods) can be achieved at the wetland reuse site, the standby wellfield, and with aquifer recharge to augment the water supply. Reclaimed water will initially be applied to the wetland reuse site at a rate of 2 inches (5 cm) per week, which corresponds to a reclaimed water flow of approximately 6 mgd (263 l/s) over 770 acres (312 hectares) of the 1,415-acre (573-hectare) site. The results of the modeling indicate that up to 6 mgd (263 l/s) of reclaimed water can be applied to the wetland reuse site without producing more than an 8-inch (20-cm) average rise in surface water levels in the wetlands. A particle tracking analysis was conducted to evaluate the fate of discharge at the wetland reuse site and the associated time of travel in the surficial aquifer. The particle tracking analysis indicated that the travel time from the point of reclaimed


water application to the point of groundwater discharge (from the standby wellfield to the M Canal) ranged from 2 to 34 years. The M Canal flows into the City’s surface water reservoir. Based on the results of the demonstration project, a 10mgd (438-l/s) reclaimed water facility was designed with operational goals for TN and TP of less than 2.0 mg/l and 0.05 mg/l (on an annual average basis) respectively, in order to minimize change in the wetland vegetation. A commitment to construction and operation of a high-quality reclaimed water facility has been provided to meet these stringent discharge requirements. Public participation for this project consisted of holding several tours and meetings with regulatory agencies, public health officials, environmental groups, media, and local residents from the early planning phases through project design. Brochures describing the project drivers, proposed processes, safety measures, and benefits to the community were identified. A public relations firm was also hired to help promote the project to elected officials and state and federal policy makers.

Figure 2-18.

Growth of Reuse in Florida

Source: Florida DEP, 2002b includes discussion of landscape irrigation, agricultural irrigation, industrial uses, groundwater recharge, indirect potable reuse, and a wide range of urban reuse activities. This rule also addresses reclaimed water ASR, blending of demineralization concentrate with reclaimed water, and the use of supplemental water supplies. Given the complexity of the program and the number of entities involved, program coordination is critical. The Reuse Coordinating Committee, which consists of representatives of the Florida DEP, Florida’s 5 water management districts, Florida Department of Health, the Public Service Commission, Florida Department of Agriculture and Consumer Services and Florida Department of Community Affairs, meets regularly to discuss reuse activities and issues. In addition, permitting staffs from the water management districts and the Florida DEP meet regularly to discuss local reuse issues and to bring potential reclaimed water users and suppliers together. Indeed, statutory and rule provisions mandate the use of reclaimed water and implementation of reuse programs (York et al., 2002). Florida’s Water Reuse Program incorporates a number of innovations and advancements. Of note is the “Statement of Support for Water Reuse”, which was signed by the heads of the agencies comprising the Reuse Coordinating Committee. EPA Region 4 also participated as a signatory party. The participating agencies committed to encouraging, promoting, and facilitating water reuse in Florida. In addition, working as a partner with the Water Reuse Committee of the Florida Water Environment Association, Florida DEP developed the “Code of Good Practices for Water Reuse.” This is a summary of key management, operation, and public involvement concepts that define quality reuse programs.


Types of Reuse Applications in Florida

Florida receives an average of more than 50 inches (127 cm) of rainfall each year. While the state may appear to have an abundance of water, continuing population growth, primarily in the coastal areas, contributes to increased concerns about water availability. The result is increased emphasis on water conservation and reuse as a means to more effectively manage state water resources (FDEP, 2002a). By state statute, Florida established the encouragement and promotion of water reuse as formal state objectives (York et al., 2002). In response, the Florida Department of Environmental Protection (FDEP), along with the state’s water management districts and other state agencies, have implemented comprehensive programs designed to achieve these objectives. As shown in Figure 2-18, the growth of reuse in Florida during 1986 to 2001 has been remarkable (FDEP, 2002b). In 2001, reuse capacity totaled 1,151 mgd (50,400 l/s), which represented about 52 percent of the total permitted capacity of all domestic wastewater treatment facilities in the state. About 584 mgd (25,580 l/s) of reclaimed water were used for beneficial purposes in 2001. The centerpiece of Florida’s Water Reuse Program is a detailed set of rules governing water reuse. Chapter 62610, Florida Administrative Code (Florida DEP, 1999),


As outlined in the Water Conservation Initiative (FDEP, 2002a), the future of Florida’s Water Reuse Program will be guided by the need to ensure that reclaimed water is used efficiently and effectively in Florida (York et al., 2002). The Water Conservation Initiative report contains 15 strategies for encouraging efficiency and effectiveness in the Water Reuse Program.

the SWFWMD and has experienced prolonged growth that has strained potable water supplies. A profile of the Tampa Bay area is given below:

Home to nearly 2.5 million people who live in the 3 counties (Pasco, Hillsborough, and Pinellas) referred to as the Tampa Bay area. is the public, using 306.2 million mgd (13,410 l/s), representing 64 percent of the water total use in the area in the year 2000. There are 38 wastewater treatment facilities in the Tampa Bay area operated by 19 public and private utilities. In 2000 these facilities:


Regionalizing Reclaimed Water in the Tampa Bay Area

„ The largest water user group in the Tampa Bay area

The Southwest Florida Water Management District (SWFMWD) is one of 5 water management districts in the state responsible for permitting groundwater and surface water withdrawals. The Tampa Bay area is within Figure 2-19.

Available Reclaimed Water in Pasco, Pinellas, and Hillsborough Counties


- Produced an annual average of 201 mgd (8,800 l/s) of treated wastewater. - 73 mgd (3,200 l/s) of reclaimed water was used for beneficial purposes, representing 36 percent use of available flows. - Of the 73 mgd (3,200 l/s), 44 mgd (1,930 l/s) (60 percent) of reclaimed water replaced the use of traditional, high-quality (potable) water resources. As the regulatory authority responsible for managing water supplies in the region, SWFWMD views the offset achieved through use of reclaimed water as an important contribution to the regional water supply. The District’s “Regional Water Supply Plan” includes a goal to effectively use 75 percent of available reclaimed water resources in order to offset existing or new uses of high quality water sources. The objectives to meet the goal by 2020 or earlier are collectively designed to enhance the use and efficiency of reclaimed water by:



When a National Technical Information Service (NTIS) number is cited in a reference, that reference is available from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 (703) 487-4650 Adamski, R., S. Gyory, A. Richardson, and J. Crook. 2000. “The Big Apple Takes a Bite Out of Water Reuse.” 2000 Water Reuse Conference Proceedings, January 30 – February 2, 2000. San Antonio, Texas. American Water Works Association, California-Nevada Section. 1997. Guidelines for the Onsite Retrofit of Facilities Using Disinfected Tertiary Recycled Water. American Water Works Association Research Foundation (AWWARF); KIWA. 1988. “The Search for a Surrogate,” American Water Works Association Research Foundation, Denver, Colorado. American Water Works Association Research Foundation (AWWARF). 2001. “An Investigation of Soil Aquifer Treatment for Sustainable Water Reuse.” Order Number 90855. Babcock, R., C. Ray, and T. Huang. 2002. “Fate of Pharmaceuticals in Soil Following Irrigation with Recycled Water.” WEFTEC 2002 Proceedings of the 75th Annual Conference and Exposition, McCormick Place, Chicago, Illinois. Bouwer, H. 1991. “Role of Groundwater Recharge in Treatment and Storage of Wastewater for Reuse.” Water Science Technology, 24:295-302. Bouwer, H. 1991. “Simple Derivation of the Retardation Equation and Application to Referential Flow and Macrodispersion.” Groundwater, 29(1): 41-46. Bouwer, H. 1988. “Systems for Artificial Recharge for Groundwater.” Proceedings of the International Symposium. Annaheim, California. American Society of Civil Engineers. Bouwer, H., and R.C. Rice. 1989. “Effect of Water Depth in Groundwater Recharge Basins on Infiltration Rate.” Journal of Irrigation and Drainage Engineering, 115:556568.

Maximizing reclaimed water locally to meet water demands in service areas Increasing the efficiency of use through technology for dealing with wet-weather flows and demand management (i.e., meters, education, etc.) Interconnecting systems to move excess flows to areas where the water is needed, when it is needed, for a regional water resource benefit



There is not enough reclaimed water in the Tampa Bay area to meet all of the irrigation and other needs in the region. However, there are opportunities to transport excess reclaimed water flows that cannot be used locally to achieve benefits to areas of high demand or other beneficial uses, such as natural system restoration. As a first step in evaluating how reclaimed water may be used in the Tampa Bay Area, the SWFWMD developed an inventory of existing water reclamation facilities, their locations, total flow and flows already committed to beneficial reuse, and flows that might be available for an expanded reuse program (Figure 2-19). Subsequent planning efforts will build on this information to evaluate interconnections between reuse systems for optimal use.


Calabrese, E.J., C.E. Gilbert, and H. Pastides. 1989. Safe Drinking Water Act, Lewis Publishers, Chelsea, Michigan. California State Water Resources Control Board. 2002. 2002 Statewide Recycled Water Survey.California State Water Resources Control Board, Office of Water Recycling, Sacramento, California. Available from index.html. California State Water Resources Control Board. 1990. California Municipal Wastewater Reclamation in 1987. California State Water Resources Control Board, Office of Water Recycling, Sacramento, California. California State Water Resources Control Board. 1980. Evaluation of Industrial Cooling Systems Using Reclaimed Municipal Wastewater. California State Water Resources Control Board, Office of Water Recycling, Sacramento, California. Camp Dresser & McKee Inc. 2001. City of Orlando, Phase I Eastern Regional Reclaimed Water Distribution System. Prepared for the City of Orlando, Florida, by Camp Dresser & McKee Inc., Maitland, Florida. Camp Dresser & McKee Inc. 1990a. City of Boca Raton, Florida Reclaimed Water System Master Plan. Prepared for the City of Boca Raton, Florida, by Camp Dresser & McKee Inc., Ft. Lauderdale, Florida. Camp Dresser & McKee Inc. 1990b. Effluent Reuse Feasibility Study and Master Plan for Urban Reuse. Prepared for the Manatee County Public Works Department and the Southwest Florida Water Management District by Camp Dresser & McKee Inc., Sarasota, Florida. Camp Dresser & McKee Inc. 1987. City of St. Petersburg Reclaimed Water System Master Plan Update. Prepared for the City of St. Petersburg, Florida, by Camp Dresser & McKee Inc., Clearwater, Florida. Carlson, R.R., K.D. Lindstedt, E.R. Bennett, and R.B. Hartman. 1982. “Rapid Infiltration Treatment of Primary and Secondary Effluents.” Journal WPCF, 54: 270-280. Chalmers, R.B., M. Patel, W. Sevenandt and D. Cutler. 2003. Meeting the Challenge of Providing a Reliable Water Supply for the Future, the Groundwater Replenishment System. WEFTEC 2003. City of Yelm. 2003. 2003 Ground Water Monitoring and Use Information. Provided by Shelly Badger, City Ad-

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Johns, F.L., R. J. Neal, and R. P. Arber Associates, Inc. 1987. “Maximizing Water Resources in Aurora, Colorado Through Reuse.” Water Reuse Symposium IV Proceedings. August 2-7, 1987. Denver, Colorado. Johnson, L.J., and J. Crook, 1998, “Using Reclaimed Water in Building for Fire Suppressions.” Proceedings of the Water Environment Federation 71st Annual Conference and Exposition. Orlando, Florida. Johnson, W.D. 1998. “Innovative Augmentation of a Community’s Water Supply – The St. Petersburg, Florida Experience.” Proceedings of the Water Environment Federation, 71st Annual Conference and Exposition. October 3-7, 1998. Orlando, Florida. Joint Task Force. 1998. Using Reclaimed Water to Augment Potable Water Supplies. Special publication prepared by a joint task force of the Water Environment Federation and the American Water Works Association. Published by the Water Environment Federation. Alexandria, Virginia. Kadlec, R.H., and R.L. Knight. 1996. “Treatment Wetlands.” Lewis Press, Boca Raton, Florida. Khan, S. J., and E. Rorije. 2002. “Pharmaceutically active compounds in aquifer storage and recovery.” Management of Aquifer Recharge for Sustainability. A. A. Belkema Publishers. Lisse, P. 169-179. Kopchynski, T., Fox, P., Alsmadi, B. and M. Berner. 1996. “The Effects of Soil Type and Effluent Pre-Treatment on Soil Aquifer Treatment”, Wat. Sci. Tech., 34:11, pp. 235-242. Lance, J.C., R.C. Rice, and R.G. Gilbert. 1980. “Renovation of Sewage Water by Soil Columns Flooded with Primary Effluent.” Journal WPCF, 52(2): 381-388. Lauer, W.C. 1991. “Denver’s Direct Potable Water Reuse Demonstration Project.” Proceedings of the International Desalination Association. Conference on Desalination and Water Reuse. Topsfield, Massachusetts. Lindsey, P., R., K. Waters, G. Fell, and A. Setka Harivandi. 1996. “The Design and Construction of a Demonstration/Research Garden Comparing the Impact of Recycled vs. Potable Irrigation Water on Landscape Plants, Soils and Irrigation Components.” Water Reuse Conference Proceedings. American Water Works Association. Denver, Colorado. Longoria, R.R., D.W. Sloan, and S.M. Jenkins. 2000. “Rate Setting for Industrial Reuse in San Marcos, Texas.”

2000. WateReuse Conference Proceedings, January 30 – February 2, 2003. San Antonio, Texas. Lundt, M. M., A. Clapham, B.W. Hounan, and R.E. Finger. 1996. “Cooling with Wastewater.” Water Reuse Conference Proceedings. American Water Works Association, Denver, Colorado. McNeal, M.B. 2002. “Aquifer Storage Recovery has a Significant Role in Florida’s Reuse Future.” 2002 WateReuse Symposium, September 8 – 11. Orlando, Florida. Medema, G. J., and P. J. Stuyzand. 2002. “Removal of Micro-organisms upon Recharge, Deep Well Injection and River Bank Infiltration in the Netherlands.” Management of Aquifer Recharge for Sustainability: A. A. Belkema Publishers. Lisse, p. 125-131. Mills, W. R. 2002. “The Quest for Water Through Artificial Recharge and Wastewater Recycling.” Management of Aquifer Recharge for Sustainability: A. A. Balkema Publishers, p. 3-10. Miyamoto, S., and J. White. 2002. “Foliar Salt Damage of Landscape Plants Induced by Sprinkler Irrigation.” Texas Water Resources Inst. TR 1202. Miyamoto, S. 2003. “Managing Salt Problems in Landscape Use of Reclaimed Water in the Southwest.” Proceedings of the Reuse Symposium. 2003. San Diego, California. National Research Council. 1998. Issues in Potable Reuse. National Academy Press. Washington, D.C. National Research Council. 1980. Drinking Water and Health, Vol. 2. pp. 252-253. National Academy Press. Washington, D.C. NCASI. 2003. Memo report from Jay Unwin. April 23, 2003. Nellor, M.H., R.B. Baird, and J.R. Smyth. 1985. “Health Effects of Indirect Potable Reuse.” Journal AWWA. 77(7): 88-96. Oaksford, E.T. 1985. Artificial Recharge: Methods, Hydraulics, and Monitoring. In: Artificial Recharge of Groundwater. T. Asano (ed) pp 69-127, Butterworth Publishers, Boston Massachusetts. Olsthoorn, T. N., and M. J. M. Mosch. 2002. “Fifty years Artificial in the Amsterdam Dune Area, In. Management


of Aquifer Recharge for Sustainability.” A. A. Balkema Publishers, Lisse, p. 29-33. Ornelas, D., and D. Brosman. 2002. “Distribution System Startup Challenges for El Paso Water Utilities.” 2002 Reuse Symposium. Orlando, Florida. Ornelas, D., and S. Miyamoto. 2003. “Sprinkler Conversion for Minimizing Foliar Salt Damage.” Proceedings of the WateReuse Symposium. 2003. San Antonio, Texas. Overman, A.R., and W.G. Leseman. 1982. “Soil and Groundwater Changes under Land Treatment of Wastewater.” Transactions of the ASAE. 25(2): 381-87. Payne, J.F., A. R. Overman, M. N. Allhands, and W. G. Leseman. 1989. “Operational Characteristics of a Wastewater Irrigation System.” Applied Engineering in Agriculture, Vol. 5(3): 355-60. PBS&J. 1992. Lakeside Lake Load Analysis Study Prepared for Arizona Department of Environmental Quality Peyton, D. 2002. “Modified Recharge Basin Floors to Control Sediment and Maximize Infiltration Efficiency. Management of Aquifer Recharge for Sustainability: A. A. Balkema Publishers. Lisse, p. 215-220. Piet, G.J. and B.C.J. Zoeteman. 1980. Organic Water Quality Changes During Sand Bank and Dune Filtration of Surface Waters in the Netherlands. Journal AWWA, 72(7) 400-414. Public Health Service. 1962. Drinking Water Standards. Publication No. 956, Washington, D.C. Pyne, R.D.G. 2002. “Groundwater Recharge and Wells: A Guide to Aquifer Storage Recovery.” Lewis Publishers, Boca Raton, Florida, p. 376. Pyne. 1995. Groundwater Recharge and Wells: A Guide to Aquifer Storage and Recovery. CRC. Boca Raton. Raines, H.K., B. Geyer, M. Bannister, C. Weeks, and T. Richardson. 2002. “Food Crop Irrigation with Recycled Water is Alive and Well in California.” 2002 WateReuse Symposium, September 8 –11. Orlando, Florida. Reed, S. and R. Bastian. 1991. “Potable Water Via Land Treatment and AWT.” Water Environment & Technology. 3(8): 40-47. Rice, R.C., and H. Bouwer. 1980. “Soil-Aquifer Treatment Using Primary Effluent.” Journal WPCF. 51(1): 84-88.

Richardson, T.G. 1998. “Reclaimed Water for Residential Toilet Flushing: Are We Ready?” Water Reuse Conference Proceedings, American Water Works Association, Denver, Colorado. Rowe, D.R. and I.M. Abdel-Magid. 1995. Handbook of Wastewater Reclamation and Reuse. CRC Press, Inc. 550 p. SAWS website. 2004. Sanitation Districts of Los Angeles County. 2002. 20012002 Annual Groundwater Recharge Monitoring Report. Sanitation Districts of Los Angeles County. Whittier, California. Sedlak, D.L., J.L. Gray, and K.E. Pinkston. 2000. “Understanding Microcontaminants in Recycled Water,” Env. Sci. Tech. News. 34 (23). Skjemstad, J. O., M. H. B. Hayes, and R. S. Swift. 2002. “Changes in Natural Organic Matter During Aquifer Storage. Management of Aquifer Recharge for Sustainability: A. A. Balkema Publishers. Lisse, p. 149-154. Sloss, E., D. F. McCaffrey, R. D. Fricker, S. A. Geschwind, and B.R. Ritz. 1999. “Groundwater Recharge with Reclaimed Water Birth Outcomes in Los Angeles County, 1982-1993.” RAND Corporation. Santa Monica, California. Sloss, E, S. A. Geschwind, D. F. McCaffrey, and B. R. Ritz. 1996. “Groundwater Recharge with Reclaimed Water: An Epidemiologic Assessment in Los Angeles County, 1987-1991.” RAND Corporation. Santa Monica, California. Sontheimer, H. 1980. “Experience with Riverbank Filtration Along the Rhine River.” Journal AWWA , 72(7): 386390. Snyder, J. K., A. K. Deb, F. M. Grablutz, and S. B. McCammon. 2002. “Impacts of Fire Flow and Distribution System Water Quality, Design, and Operation.” AWWA Research Foundation. Denver, Colorado. Solley, Wayne B., R. R. Pierce, H. and A. Perlman. 1998. “U.S. Geological Survey Circular 1200: Estimated Use of Water in the United States in 1995.” Denver, Colorado. Southwest Florida Water Management District. 2002. “Tampa Bay Area Regional Reclaimed Water Initiative.”


Southwest Florida Water Management District, Brooksville, Florida. State of California. 1987. Report of the Scientific Advisory Panel on Groundwater Recharge with Reclaimed Wastewater. Prepared for State Water Resources Control Board, Department of Water Resources, and Department of Health Services. Sacramento, California. Stuyzand, P. J. 2002. “Quantifying the Hydrochemical Impact and Sustainability of Artificial Recharge Systems. Management of Aquifer Recharge for Sustainability: A. A. Balkema Publishers. Lisse, p. 77-82. Tanji, K.K. (ed.) 1990. Agricultural Salinity Assessment and Management. American Society of Civil Engineers. New York, New York. Thomas, M., G. Pihera, and B. Inham. 2002. “Constructed Wetlands and Indirect Potable Reuse in Clayton County, Georgia.” Proceedings of the Water Environment Federation 75th Annual Technical Exhibition & Conference (on CD-ROM), September 28 – October 2, 2002. Chicago, Illinois. Toze, S., and J. Hanna. 2002. “The Survival Potential of Enteric Microbial Pathogens in a Reclaimed Water ASR Project.” Management of Aquifer Recharge for Sustainability: A. A. Balkems Publishers. Lisse, p. 139142. Tsuchihashi, R., T. Asano, and R. H. Sakaji. 2002. “Health Aspects of Groundwater Recharge with Reclaimed Water.” Management of Aquifer Recharge for Sustainability. A. A. Belkema Publishers. Lisse, p. 11-20. Turney, D.T., Lansey, K.E., Quanrud, D.M. and R. Arnold (In Press) “Endocrine Disruption in Reclaimed Water: Fate During Soil Aquifer Treatment.” Journal of Environmental Engineering. U.S. EPA. 2001. “Removal of Endocrine Disruptor Chemicals Using Drinking Water Treatment Processes.” Technology Transfer and Support Division. Cincinnati, Ohio, EPA/625/R-00/015. U.S. EPA . 1999a. “Treatment Wetland Habitat and Wildlife Use Assessment: Executive Summary” EPA 832-S99-001. Office of Water. Washington, D.C. U.S. EPA. 1999b. “Free Water Surface Wetlands for Wastewater Treatment: A Technology Assesment” EPA832-S-99-002. Office of Water. Washington, D.C.

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CHAPTER 3 Technical Issues In Planning Water Reuse Systems
This chapter considers technical issues associated with planning the beneficial reuse of reclaimed water derived from domestic wastewater facilities. These technical issues include the:

Technical issues of concern in specific reuse applications are discussed in Chapter 2, “Types of Reuse Applications.”

Identification and characterization of potential demands for reclaimed water of reclaimed water to determine their potential for reuse


Planning Approach

„ Identification and characterization of existing sources

One goal of the Guidelines for Water Reuse is to outline a systematic approach to planning for reuse so that planners can make sound preliminary judgments about the local feasibility of reuse, taking into account the full range of key issues that must be addressed in implementing reclamation programs. Figure 3-1 illustrates a 3-phase approach to reuse planning. This approach groups reuse planning activities into successive stages that include preliminary investigations, screening of potential markets, and detailed evaluation of selected markets. Each stage of activity builds on previous stages until enough information is available to develop a conceptual reuse plan and to begin negotiating the details of reuse with selected users. At each stage, from early planning through implementation, public involvement efforts play an important role. Public involvement efforts provide guidance to the planning process and outline steps that must be taken to support project implementation.

„ Treatment requirements for producing a safe and re-

liable reclaimed water that is suitable for its intended applications

Storage facilities required to balance seasonal fluctuations in supply with fluctuations in demand Supplemental facilities required to operate a water reuse system, such as conveyance and distribution networks, operational storage facilities, alternative supplies, and alternative disposal facilities Potential environmental impacts of implementing water reclamation Identification of knowledge, skills, and abilities necessary to operate and maintain the proposed system




Figure 3-1.

Phases of Reuse Program Planning



Preliminary Investigations

„ What

are the legal liabilities of a purveyor or user of reclaimed water?

This is a fact-finding phase, meant to rough out physical, economic, and legal/institutional issues related to water reuse planning. The primary task is to locate all potential sources of effluent for reclamation and reuse and all potential markets for reclaimed water. It is also important to identify institutional constraints and enabling powers that might affect reuse. This phase should be approached with a broad view. Exploration of all possible options at this early planning stage will establish a practical context for the plan and also help to avoid creating dead-ends in the planning process. Questions to be addressed in this phase include:

The major task of this phase involves conducting a preliminary market assessment to identify potential reclaimed water users. This calls for defining the water market through discussions with water wholesalers and retailers, and by identifying major water users in the market. The most common tools used to gather this type of information are telephone contacts and/or letters to potential reuse customers. Often, a follow-up phone contact is needed in order to determine what portion of total water use might be satisfied by reclaimed water, what quality of water is required for each type of use, and how the use of reclaimed water might affect the user’s operations or discharge requirements. This early planning stage is an ideal time to begin to develop or reinforce strong working relationships, among wastewater managers, water supply agencies, and potential reclaimed water users. These working relationships will help to develop solutions that best meet a particular community’s needs. Potential users will be concerned with the quality of reclaimed water and reliability of its delivery. They will also want to understand state and local regulations that apply to the use of reclaimed water. Potential customers will also want to know about constraints to using reclaimed water. They may have questions about connection costs or additional wastewater treatment costs that might affect their ability to use the product.

What local sources of effluent might be suitable for reuse? What are the potential local markets for reclaimed water? What other nontraditional freshwater supplies are available for reuse? What are the present and projected reliability benefits of fresh water in the area? What are the present and projected user costs of fresh water in the area? What sources of funding might be available to support the reuse program? How would water reuse “integrate,” or work in harmony with present uses of other water resources in the area? What public health considerations are associated with reuse, and how can these considerations be addressed? ter reuse?







Screening of Potential Markets



„ What are the potential environmental impacts of wa-


What type of reuse system is likely to attract the public’s interest and support? What existing or proposed laws and regulations affect reuse possibilities in the area? What local, state, or federal agencies must review and approve implementation of a reuse program?



The essence of this phase is to compare the unit costs of fresh water to a given market and the unit costs of reclaimed water to that same market. On the basis of information gathered in preliminary investigations, one or more “intuitive projects” may be developed that are clear possibilities, or that just “seem to make sense.” For example, if a large water demand industry is located next to a wastewater treatment plant, there is a strong potential for reuse. The industry has a high demand for water, and costs to convey reclaimed water would be low. Typically, the cost-effectiveness of providing reclaimed water to a given customer is a function of the customer’s potential demand versus the distance of the customer from the source of reclaimed water. In considering this approach, it should be noted that a concentration of smaller customers might represent a service area that would be as cost-effective to serve as a single large user. Once these anchor customers are identified, it is often beneficial to search for smaller customers located along the proposed path of the transmission system.


The value of reclaimed water – even to an “obvious” potential user will depend on the:

„ How complicated would program implementation be,

given the number of agencies that would be involved in each proposed system?
„ To what degree would each system advance the “state-

Quality of water to be provided, as compared to the user’s requirements Quantity of fresh water available and the ability to meet fluctuating demand of agencies responsible for enforcing applicable laws

of-the-art” in reuse?
„ „ What level of chemical or energy use would be asso-

ciated with each system?
„ Effects of laws that regulate reuse, and the attitudes „ How would each system impact land use in the area?


Present and projected future cost of fresh water to the user

These questions all involve detailed study, and it may not be cost-effective for public entities to apply the required analyses to every possible reuse scenario. A useful first step is to identify a wide range of candidate reuse systems that might be suitable in the area and to screen these alternatives. Then, only the most promising project candidates move forward with detailed evaluations. In order to establish a comprehensive list of reuse possibilities, the following factors should be taken into account:

Levels of treatment – if advanced wastewater treatment (AWT) is currently required prior to discharge of effluent, cost savings might be available if a market exists for secondary treated effluent. Project size – the scale of reuse can range from conveyance of reclaimed water to a single user up to the general distribution of reclaimed water for a variety of nonpotable uses. Conveyance network – different distribution routes will have different advantages, taking better advantage of existing rights-of-way, for example, or serving a greater number of users.


Review of user requirements could enable the list of potential markets to be reduced to a few selected markets for which reclaimed water could be of significant value. The Bay Area Regional Water Recycling Program (BARWRP) in San Francisco, California used a sophisticated screening and alternative analysis procedure. This included use of a regional GIS-based market assessment, a computer model to evaluate cost-effective methods for delivery, detailed evaluation criteria, and a spreadsheet-based evaluation decision methodology (Bailey et al., 1998). The City of Tucson, Arizona, also used a GIS database to identify parcels such as golf courses, parks, and schools with a potential high demand for turf irrigation. In Cary, North Carolina, the parcel database was joined to the customer-billing database allowing large water users to be displayed on a GIS map. This process was a key element in identifying areas with high concentrations of dedicated irrigation meters on the potable water system (CDM, 1997). As part of an evaluation of water reclamation by the Clark County Sanitation District, Nevada, the alternatives analysis was extended beyond the traditional technical, financial, and regulatory considerations to include intangible criteria such as:
„ Public acceptance including public education „ „


Sensitivity to neighbors Administrative agencies for the project

In addition to comparing the overall costs estimated for each alternative, several other criteria can be factored into the screening process. Technical feasibility may be used as one criterion, and the comparison of estimated unit costs of reclaimed water with unit costs of fresh water, as another. An even more complex screening process may include a comparison of weighted values for a variety of objective and subjective factors, such as:

„ Institutional arrangements to implement „

Impacts to existing developments as facilities are constructed

Source: Pai et. al., 1996

How much flexibility would each system offer for future expansion or change? How much fresh water use would be replaced by each system?


Detailed Evaluation of Selected Markets


The evaluation steps contained in this phase represent the heart of the analyses necessary to shape a reuse program. At this point, a certain amount of useful data


should be known including the present freshwater consumption and costs for selected potential users and a ranking of “most-likely” projects. In this phase, a more detailed look at conveyance routes and storage requirements for each selected system will help to refine preliminary cost estimates. Funding and benefit options can be compared, user costs developed, and a comparison made between the costs and benefits of fresh water versus reclaimed water for each selected system. The detailed evaluation will also look in more detail at the environmental, institutional, and social aspects of each project. Questions that may need to be addressed as part of the detailed evaluation include:


What are the prospects of industrial source control measures in the area, and would institution of such measures reduce the additional treatment steps necessary to permit reuse? candidate reuse system? Are they likely to remain in their present locations? Are process changes being considered that might affect their ability to use reclaimed water?

„ How “stable” are the potential users in each selected

What are the specific water quality requirements of each user? What fluctuation can be tolerated? What is the daily and seasonal water use demand pattern for each potential user? Can fluctuations in demand best be met by pumping capacity or by using storage? Where would storage facilities best be located? If additional effluent treatment is required, who should own and operate the additional treatment facilities? What costs will the users in each system incur in connecting to the reclaimed water delivery system? Will industrial users in each system face increased treatment costs for their waste streams as a result of using reclaimed water? If so, is increased internal recycling likely, and how will this affect their water use? to be spread over the entire service area?

Many of these questions can be answered only after further consultation with water supply agencies and prospective users. Both groups may seek more detailed information as well, including the preliminary findings made in the first 2 phases of effort. The City of Tampa set the following goals and objectives for their first residential reclaimed water project:
„ „


Demonstrate customer demand for the water Demonstrate customer willingness to pay for the service subsidized by any utility customer not receiving reclaimed water


„ Show that the project would pay for itself and not be



Make subscription to the reclaimed water service voluntary


Source: Grosh et. al., 2002 Detailed evaluations should lead to a preliminary assessment of technical feasibility and costs. Comparison among alternative reuse programs will be possible, as well as preliminary comparison between these programs and alternative water supplies, both existing and proposed. In this phase, economic comparisons, technical optimization steps, and environmental assessment activities leading to a conceptual plan for reuse might be accomplished by working in conjunction with appropriate consulting organizations.


„ Will customers in the service area allow project costs


What interest do potential funding agencies have in supporting each type of reuse program being considered? What requirements would these agencies impose on a project eligible for funding? to make a change to their irrigation patterns or to provide better control of any irrigation discharges?


Potential Uses of Reclaimed Water

„ Will use of reclaimed water require agricultural users

„ What payback period is acceptable to users who must

invest in additional facilities for onsite treatment, storage, or distribution of reclaimed water?

Urban public water supplies are treated to satisfy the requirements for potable use. However, potable use (drinking, cooking, bathing, laundry, and dishwashing) represents only a fraction of the total daily residential use of treated potable water. The remainder may not require water of potable quality. In many cases, water used for nonpotable purposes, such as irrigation, may be drawn from the same ground or surface source as


municipal supplies, creating an indirect demand on potable supplies. The Guidelines examine opportunities for substituting reclaimed water for potable water supplies where potable water quality is not required. Specific reuse opportunities include:
„ Urban „

The remainder of the water use categories are mining and industrial/commercial with 8 percent of the demand. The 2 largest water use categories, thermoelectric power and agricultural irrigation, account for 80 percent of the total water use. These water uses present a great potential for supplementing with reclaimed water. Figure 3-3 provides a flow chart illustrating the source, use, and disposition of fresh water in the U.S. Of the 341,000 mgd (129 x 107 m3/d) of fresh water used in the U.S., only 29 percent is consumptively used and 71 percent is return flow. This amounts to a total of 241,000 mgd (91 x 107 m3/d), of which 14 percent originates from domestic and commercial water use. Domestic wastewater comprises a large portion of this number. Figure 3-4 shows estimated wastewater effluent produced daily in each state, representing the total potential reclaimed water supply from existing wastewater treatment facilities. Figure 3-5 shows the estimated water demands by state in the United States. Estimated water demands are equal to the total fresh and saline withdrawals for all water-use categories (public supply, domestic, commercial, irrigation, livestock, industrial, mining, and thermoelectric power). Areas where high water demand exists might benefit by augmenting existing water supplies with reclaimed water. Municipalities in coastal and arid states, where water demands are high and freshwater supplies are limited, appear to have a reasonable supply of wastewater effluent that could, through proper treatment and reuse, greatly extend their water supplies. Arid regions of the U.S. (such as the southwest) are candidates for wastewater reclamation, and significant reclamation projects are underway throughout this region. Yet, arid regions are not the only viable candidates for water reuse. Local opportunities may exist for a given municipality to benefit from reuse by extending local water supplies and/or reducing or eliminating surface water discharge. For example, the City of Atlanta, Georgia, located in the relatively water-rich southeast, has experienced water restrictions as a result of recurrent droughts. In south Florida, subtropical conditions and almost 55 inches (140 cm) per year of rainfall suggest an abundance of water; however, landscaping practices and regional hydrogeology combine to result in frequent water shortages and restrictions on water use. Thus, opportunities for water reclamation and reuse must be examined on a local level to judge their value and feasibility.


„ Agricultural „ Environmental and Recreational „ Groundwater Recharge „ Augmentation of Potable Supplies

The technical issues associated with the implementation of each of these reuse alternatives are discussed in detail in Chapter 2. The use of reclaimed water to provide both direct and indirect augmentation of potable supplies is also presented in Chapter 2.


National Water Use

Figure 3-2 presents the national pattern of water use in the U.S. according to the U.S. Geological Survey (Solley et al., 1998). Total water use in 1995 was 402,000 mgd (152 x 107 m3/d) with 341,000 mgd (129 x 107 m3/d) being fresh water and 61,000 mgd (23 x 107 m3/d) saline water. The largest freshwater demands were associated with agricultural irrigation/livestock and thermoelectric power, representing 41 and 39 percent, respectively, of the total freshwater use in the United States. Public and domestic water uses constitute 12 percent of the total demand. Figure 3-2. 1995 U.S. Fresh Water Demands by Major Uses


Potential Reclaimed Water Demands

Source: Solley et. al., 1998

Residential water demand can further be categorized as indoor use, which includes toilet flushing, cooking, laundry, bathing, dishwashing, and drinking; or outdoor use,


Figure 3-3.

Fresh Water Source, Use and Disposition

Source: Solley et. al., 1998


Figure 3-4.

Wastewater Treatment Return Flow by State, 1995

Source: Solley et al., 1998

Figure 3-5.

Total Withdrawals

Source: Solley et al., 1998


which consists primarily of landscape irrigation. Outdoor use accounts for approximately 31 percent of the residential demand, while indoor use represents approximately 69 percent (Vickers, 2001). Figure 3-6 presents the average residential indoor water use by category. It should be noted that these are national averages, and few residential households will actually match these figures. Inside the home, the largest use of water is toilet flushing (almost 30 percent). The potable use (cooking, drinking, bathing, laundry, and dishwashing) represents about 60 percent of the indoor water use or about 40 percent of the total residential (outdoor and indoor) demand. Reclaimed water could be used for all nonpotable uses (toilet flushing and outdoor use), which are approximately 50 percent of the total residential water demand. Leaks are neglected in these calculations. Approximately 38 billion gallons of water is produced daily in the U.S. for domestic and public use. On average, a typical American household consumes at least 50 percent of their water through lawn irrigation. The U.S. has a daily requirement of 40 billion gallons (152 million m3) a day of fresh water for general public use. This requirement does not include the 300 billion gallons (1,135 million m3) used for agricultural and commercial purposes. For example, a dairy cow must consume 4 gallons (15 l) of water to produce 1 gallon (4 l) of milk, and it takes 300 million gallons (1.1 million m3) of water to produce a 1day supply of U.S. newsprint (American Water Works Association Website, 2003). The need for irrigation is highly seasonal. In the North where turf goes dormant, irrigation needs will be zero in the winter months. However, irrigation demand may repFigure 3-6. Average Indoor Water Usage (Total = 69.3 gpcd)

resent a significant portion of the total potable water demand in the summer months. In coastal South Carolina, winter irrigation use is estimated to be less than 10 percent of the total potable demand. This increases to over 30 percent in the months of June and July. In Denver, during July and August when temperatures exceed 90 °F (32 °C), approximately 80 percent of all potable water may be used for irrigation. Given the seasonal nature of urban irrigation, eliminating this demand from the potable system through reuse will result in a net annual reduction in potable demands and, more importantly, may also significantly reduce peak-month potable water demands. It is not surprising then that landscape irrigation currently accounts for the largest urban use of reclaimed water in the U.S. This is particularly true of urban areas with substantial residential areas and a complete mix of landscaped areas ranging from golf courses to office parks to shopping malls. Urban areas also have schools, parks, and recreational facilities, which require regular irrigation. Within Florida, for example, studies of potable water consumption have shown that 50 to 70 percent of all potable water produced is used for outside purposes, principally irrigation. The potential irrigation demand for reclaimed water generated by a particular urban area can be estimated from an inventory of the total irrigable acreage to be served by the reuse system and the estimated weekly irrigation rates, determined by factors such as local soil characteristics, climatic conditions, and type of landscaping. In some states, recommended weekly irrigation rates are available from water management agencies, county or state agricultural agents, and irrigation specialists. Reclaimed water demand estimates should also take into account any other proposed uses for reclaimed water within the proposed service area, such as industrial cooling and process water, decorative fountains, and other aesthetic water features. Agricultural irrigation represents 40 percent of total water demand nationwide and presents another significant opportunity for water reuse, particularly in areas where agricultural sites are near urban areas and can easily be integrated with urban reuse applications. Such is the case in Orange County, California, where the Irvine Ranch Water District provides reclaimed water to irrigate urban landscape and mixed agricultural lands (orchards and vegetable row crops). As agricultural land use is displaced by residential development in this growing urban area, the District has the flexibility to convert its reclaimed water service to urban irrigation. In Manatee County, Florida, agricultural irrigation is a significant component of a county-wide water reuse pro-

Source: Vickers, 2001


gram. During 2002, the County’s 3 water reclamation facilities, with a total treatment capacity of 34.4 mgd (1,500 l/s), provided about 10.2 mgd (446 l/s) of reclaimed water. This water was used to irrigate golf courses, parks, schools, residential subdivisions, a 1,500-acre (600-hectare) gladioli farm, and about 6,000 acres (2,400 hectares) of mixed agricultural lands (citrus, ridge and furrow crops, sod farms, and pasture). The original 20-year reuse agreements with the agricultural users are being extended for 10 years, ensuring a long-term commitment to reclaimed water with a significant water conservation benefit. The urban reuse system has the potential to grow as development grows. Manatee County has more than 385 acres (154 hectares) of lake storage (1,235 million gallons or 47 x 105 m3 of volume) and 2 reclaimed water aquifer storage and recovery (ASR) projects. A detailed inspection of existing or proposed water use is essential for planning any water reuse system. This information is often available through municipal billing records or water use monitoring data that is maintained to meet the requirements of local or regional water management agencies. In other cases, predictive equations may be required to adequately describe water demands. Water needs for various reuse alternatives are explored further in Chapter 2. In addition to expected nonpotable uses for reclaimed water, a review of literature shows consideration and implementation of reuse projects for a wide variety of demands including toilet flushing, commercial car washing, secondary and primary sources of fire protection, textile mills to maintain water features, cement manufacturing, and make-up water for commercial air conditioners. By identifying and serving a variety of water uses with reclaimed water, the utilization of reclaimed water facilities can be increased, thereby increasing the cost effectiveness of the system while at the same time increasing the volume of potable water conserved.

the District’s service area for groundwater recharge, landscape irrigation, agricultural, commercial, and industrial purposes. It is estimated that more than 195 billion gallons (740 x 106 m3) of reclaimed water will be reused by 2010. Due to long-term conservation programs, additional supply agreements, and an increase in the reclaimed water supply the District expects to meet the area’s water needs for the next ten years even during times of critical drought (Metropolitan, 2002). Perhaps the greatest benefit of urban reuse systems is their contribution to delaying or eliminating the need to expand potable water supply and treatment facilities. The City of St. Petersburg, Florida, has experienced about a 10 percent population growth since 1976 without any significant increase in potable water demand because of its urban reuse program. Prior to the start-up of its urban reuse system, the average residential water demand in a study area in St. Petersburg was 435 gallons per day (1,650 l/d). After reclaimed water was made available, the potable water demand was reduced to 220 gallons per day (830 l/d) (Johnson and Parnell, 1987). Figure 3-7 highlights the City of St. Petersburg’s estimated potable water savings since implementing an urban reuse program. In 2001, Florida embarked on the Water Conservation Initiative (FDEP, 2002) – a program designed to promote water conservation in an effort to ensure water availability for the future. Recognizing the conservation and recharge potential of water reuse, a Water Reuse Work Group was convened to address the effective and efficient use of reclaimed water as a component in overall strategies to ensure water availability. The Water Reuse Work Group published its initial report in 2001 (FDEP, 2001) and published a more detailed strategy report in 2003 (FDEP, 2003). The final reuse strategy report includes 16 major strategies designed to ensure efficient and effective water reuse. Of particular note are strategies that encourage the use of reclaimed water meters and volume-based rates, in addition to encouraging groundwater recharge and indirect potable reuse. Currently, approximately 20 percent of all water supplied by the Irvine Ranch Water District in southern California is reclaimed water. Total water demand is expected to reach 69 mgd (3,024 l/s) in Irvine by 2010. At that time Irvine expects to be able to provide service to meet approximately 26 mgd (1,139 l/s) of this demand with reclaimed water (Irvine Ranch Water District, 2002). An aggressive urban reuse program in Altamonte Springs, Florida is credited with a 30 percent reduction in potable water demands (Forest et al., 1998).


Reuse and Water Conservation

The need to conserve the potable water supply is an important part of urban and regional planning. For example, the Metropolitan Water District of Southern California predicted in 1990 that by the year 2010 water demands would exceed reliable supplies by approximately 326 billion gallons (1,200 x 109 m3) annually (Adams, 1990). To help conserve the potable water supplies, the Metropolitan Water District developed a multi-faceted program that includes conservation incentives, rebate programs, groundwater storage, water exchange agreements, reservoir construction, and reclaimed water projects. Urban reuse of reclaimed water is an essential element of the program. In 2001, approximately 62 billion gallons (330 x 106 m3) of reclaimed water were used in


Figure 3-7.

Potable and Reclaimed Water Usage in St. Petersburg, Florida


Sources of Reclaimed Water


Locating the Sources

Under the broad definition of water reclamation and reuse, sources of reclaimed water may range from industrial process waters to the tail waters of agricultural irrigation systems. For the purposes of these guidelines, however, the sources of reclaimed water are limited to the effluent generated by domestic wastewater treatment facilities (WWTFs). Treated municipal wastewater represents a significant potential source of reclaimed water for beneficial reuse. As a result of the Federal Water Pollution Control Act Amendments of 1972, the Clean Water Act of 1977 and its subsequent amendments, centralized wastewater treatment has become commonplace in urban areas of the U.S. In developed countries, approximately 73 percent of the population is served by wastewater collection and treatment facilities. Yet only 35 percent of the population of developing countries is served by wastewater collection. Within the U.S., the population generates an estimated 41 billion gallons per day (1.8 x 106 l/s) of potential reclaimed water (Solley et al., 1998). As the world population continues to shift from rural to urban, the number of centralized wastewater collection and treatment systems will also increase, creating significant opportunities to implement water reuse systems to augment water supplies and, in many cases, improve the quality of surface waters.

In areas of growth and new development, completely new collection, treatment, and distribution systems may be designed from the outset with water reclamation and reuse in mind. In most cases, however, existing facilities will be incorporated into the water reuse system. In areas where centralized treatment is already provided, existing WWTFs are potential sources of reclaimed water. In the preliminary planning of a water reuse system incorporating existing facilities, the following information is needed for the initial evaluation:
„ Residential areas and their principal sewers „ Industrial areas and their principal sewers „ Wastewater treatment facilities „ Areas with combined sewers „

Existing effluent disposal facilities

„ Areas and types of projected development „ Locations of potential reclaimed water users

For minimizing capital costs, the WWTFs ideally should be located near the major users of the reclaimed water. However, in adapting an existing system for water reuse, other options are available. For example, if a trunk


sewer bearing flows to a WWTF passes through an area of significant potential reuse, a portion of the flows can be diverted to a new “satellite” reclamation facility to serve that area. The sludge produced in the satellite reclamation facility can be returned to the sewer for handling at the WWTF. By this method, odor problems may be reduced or eliminated at the satellite reclamation facility. However, the effects of this practice can be deleterious to both sewers and downstream treatment facilities. Alternatively, an effluent outfall passing through a potential reuse area could be tapped for some or all of the effluent, and additional treatment could be provided, if necessary, to meet reclaimed water quality standards. These alternative configurations are illustrated in Figure 3-8. Figure 3-8. Three Configuration Alternatives for Water Reuse Systems


Characterizing the Sources

Existing sources must be characterized to roughly establish the wastewater effluent’s suitability for reclamation and reuse. To compare the quality and quantity of available reclaimed water with the requirements of potential users, information about the operation and performance of the existing WWTF and related facilities must be examined. Important factors to consider in this preliminary stage of reuse planning are:
„ Level of treatment (e.g., primary, secondary, advanced)

and specific treatment processes (e.g., ponds, activated sludge, filtration, disinfection, nutrient removal, disinfection)
„ Effluent water quality „ Effluent quantity (use of historical data to determine

daily and season at average, maximum, and minimum flows)
„ Industrial wastewater contributions to flow „

System reliability mission)

„ Supplemental facilities (e.g., storage, pumping, trans-

Level of Treatment and Processes

Meeting all applicable treatment requirements for the production of safe, reliable reclaimed water is one of the keys to operating any water reuse system. Thus careful analysis of applicable state and local requirements and provision of all necessary process elements are critical in designing a reuse system. Because of differing environmental conditions from region to region across the country, and since different end uses of the reclaimed water require different levels of treatment, a universal quality standard for reclaimed water does not exist. In the past, the main objective of treatment for reclaimed water was secondary treatment and disinfection. As wastewater effluent is considered a source for more and more uses, such as industrial process water or even potable supply water, the treatment focus has expanded beyond secondary treatment and disinfection to include treatment for other containments such as metals, dissolved solids, and emerging contaminants (such as pharmaceutical residue and endocrine disruptors). However, at this early planning stage, only a preliminary assessment of the compatibility of the secondary effluent quality and treatment facilities with potential reuse applications is needed. A detailed discussion of treatment re-


quirements for water reuse applications is provided in Section 3.4. Knowledge of the chemical constituents in the effluent, the level of treatment, and the treatment processes provided is important in evaluating the WWTF’s suitability as a water reclamation facility and determining possible reuse applications. An existing plant providing at least secondary treatment, while not originally designed for water reclamation and reuse, can be upgraded by modifying existing processes or adding new unit processes to the existing treatment train to supply reclaimed water for most uses. For example, with the addition of chemicals, filters, and other facilities to ensure reliable disinfection, most secondary effluents can be enhanced to provide a source of reclaimed water suitable for unrestricted urban reuse. However, in some parts of the U.S., the effluent from a secondary treatment system may contain compounds of concern. Such effluent may not be used because it could result in water quality problems. In these cases, treatment processes must be selected to reduce these compounds before they are released. This can create additional disposal issues as well. A typical example would be the presence of elevated TDS levels within the effluent, resulting in problems where the reclaimed water is used for irrigation (Sheikh et al., 1997; Dacko, 1997; Johnson, 1998). In some cases, existing processes necessary for effluent disposal practices may no longer be required for water reuse. For example, an advanced wastewater treatment plant designed to remove nitrogen and/or phosphorus would not be needed for agricultural or urban irrigation, since the nutrients in the reclaimed water are beneficial to plant growth. In addition to the unit processes required to produce a suitable quality of reclaimed water, the impact of any return streams (e.g., filter backwash, RO concentrate return, etc.) to the WWTF’s liquid and solids handling processes should be considered. Reclaimed Water Quality

trial reuse, however, nutrients may encourage biological growths that could cause fouling. Where the latter uses are a small fraction of the total use, the customer may be obliged to remove the nutrients or blend reclaimed water with other water sources. The decision is based on case-by-case assessments. In some cases, the water quality data needed to assess the suitability of a given source are not included in the WWTF’s existing monitoring requirements and will have to be gathered specifically for the reuse evaluation. Coastal cities may experience saltwater infiltration into their sewer system, resulting in elevated chloride concentrations in the effluent or reclaimed water. Chloride levels are of concern in irrigation because high levels are toxic to many plants. However, chloride levels at WWTFs typically are not monitored. Even in the absence of saltwater infiltration, industrial contributions or practices within the community being served may adversely impact reclaimed water quality. The widespread use of water softeners may increase the concentration of salts to levels that make the reclaimed water unusable for some applications. High chlorides from saltwater infiltration led the City of Punta Gorda, Florida to cease reclaimed water irrigation in 2001. This facility had irrigated an underdrained agricultural site for almost 20 years, but flow discharged from the underdrains caused a violation of conductivity limitations in the receiving water. Damage to landscape plants in the City of St. Petersburg, Florida, was traced to elevated chlorides in the reclaimed water. This coastal city operates 4 reclamation plants and those serving older beach communities are prone to saltwater infiltration. In response to this problem, the City initiated on-line monitoring of conductance in order to identify and halt the use of unacceptable water. The City also developed a planting guide for reclaimed water customers to identify foliage more and less suitable for use with reclaimed water service (Johnson, 1998). The Carmel Area Wastewater District in California experienced a similar problem with golf course turf associated with elevated sodium. This was due to a combination of the potable water treatment processes being used, and the prevalence of residential and commercial water softeners. Solutions included the use of gypsum, periodic use of potable water for irrigation to flush the root zone, a switch from sodium hydroxide to potassium hydroxide for corrosion control, and attempts to reduce the use of self-regenerating water softeners (Sheikh et al., 1997). Some coastal communities, or areas where salinity is a concern, have begun to restrict the discharge of chemical salts into the sanitary sewer system either by requiring their placement in a special brine line or by charging a fee for their treatment and removal (Sheikh and Rosenblum, 2002). A California state law recently gave

Effluent water quality sampling and analysis are required as a condition of WWTF discharge permits. The specific parameters tested are those required for preserving the water quality of the receiving water body, (e.g., biochemical oxygen demand, suspended solids, coliforms or other indicators, nutrients, and sometimes toxic organics and metals). This information is useful in the preliminary evaluation of a wastewater utility as a potential source of reclaimed water. For example, as noted earlier, the nitrogen and phosphorus in reclaimed water represents an advantage for certain irrigation applications. For indus-


local jurisdictions the ability to prohibit the use of selfregenerating water softeners that had been previously exempt from regulation by a prior statute (California Health and Safety Code). The West Basin Municipal Water District in southwest Los Angeles County, California, created designer reclaimed water of different qualities to increase their reclaimed water customer base. Table 3-1 describes the 5 different grades of designer water they produce and supply to their 200-square mile area of customers. For the purpose of reuse planning, it is best to consider reclaimed water quality from the standpoint of water supply, (i.e., what quality is required for the intended use?). Where a single large customer dominates the demand for reclaimed water, the treatment selected may suit that particular, major customer. In Pomona, California, activated carbon filters were used in place of conventional sand filters at the reclamation plant to serve paper mills that require low color in their water supply. Industrial reuse might be precluded if high levels of dissolved solids, dissolved organic material, chlorides, phosTable 3-1.
Grade Name

phates, and nutrients are present, unless additional treatment is provided by the industrial facility. Recreational reuse might be limited by nutrients, which could result in unsightly and odorous algae blooms. Trace metals in high concentrations might restrict the use of reclaimed water for agricultural and horticultural irrigation. Reclaimed Water Quantity

Just as the potable water purveyor must meet diurnal and seasonal variations in demand, so too must the purveyor meet variations in demand for reclaimed water. Diurnal and seasonal fluctuations in supply and demand must be taken into account at the preliminary design stage of any water reclamation system. Such an approach is warranted, given the fact that diurnal and seasonal supplies and demands for reclaimed water often exhibit more variations than that of potable water and, in many cases, the peaks in supply and demand are independent of one another. For example, WWTF flows tend to be low at night, when urban irrigation demand tends to be high. Seasonal flow fluctuations may occur in resort areas due to the influx

Five Grades of Reclaimed Water Produced by West Basin MWD
Grade 1 Tertiary Secondary effluent; additional filtration and disinfection Landscape; golf course irrigation Grade 2 Nitrified Tertiary water with ammonia removal Cooling towers Grade 3 Pure RO Grade 4 Softened RO Grade 5 Ultra-Pure RO


Secondary water plus micro-Grade 3 plus lime softening Double pass RO filtration and RO treatment Low pressure boiler feed for refineries Indirect potable reuse for the Water Replenishment District Softening the water preserves the pipes that deliver the water to the injection wells. Microfiltration and RO have been perceived as providing acceptable treatment for indirect potable reuse. High pressure boiler feed for refineries


Quality Drivers

Human contact and health requirements

Need to reduce contaminants that cause Need to remove ammonia scaling; strong desire to to reduce corrosion use the water multiple times in the process

High pressure increases the need to further reduce contaminants that cause scaling. Desire to use the water multiple times in the process


No contractual guarantee; 100% reliable due to constant source 25 - 40% discount from baseline standard 2,600

No information provided Approximately 20% discounted from baseline standard 8,300

No contractual guarantees. No contractual guarantees. No contractual guarantees May be perceived as more Probably perceived as more reliable reliable 100% price premium Equal to baseline standard 20% discount from baseline compared to the baseline or slightly higher standard standard 6,500 7,300 2,600

Price 2001-02 Volume (AF)

Adapted from: “West Basin Municipal Water District: 5 Designer (Recycled) Waters to Meet Customer’s Needs” produced by Darryl G. Miller, General Manager, West Basin Municipal Water District, Carson, California.


of tourists, and seasons of high flow do not necessarily correspond with seasons of high irrigation demand. Figure 3-9 illustrates the fluctuations in reclaimed water supply and irrigation demand in a southwest Florida community. Treatment facilities serving college campuses, resort areas, etc. also experience significant fluctuations in flow throughout the year. Where collection systems are prone to infiltration and inflow, significant fluctuations in flow may occur during the rainy season. Information about flow quantities and fluctuations is critical in order to determine the size of storage facilities needed to balance supply and demand in water reuse systems. A more detailed discussion of seasonal storage requirements is provided in Section 3.5. Operational storage requirements to balance diurnal flow variations are detailed in Section 3.6.3. Industrial Wastewater Contributions

with substantial industrial flows will require identification of the constituents that may interfere with particular reuse applications, and appropriate monitoring for parameters of concern. Wastewater treatment facilities receiving substantial amounts of high-strength industrial wastes may be limited in the number and type of suitable reuse applications.


Treatment Requirements for Water Reuse

Industrial waste streams differ from domestic wastewater in that they may contain relatively high levels of elements and compounds, which may be toxic to plants and animals or may adversely impact treatment plant performance. Where industrial wastewater flow contributions to the WWTF are significant, reclaimed water quality may be affected. The degree of impact will, of course, depend on the nature of the industry. A rigorous pretreatment program is required for any water reclamation facility that receives industrial wastes to ensure the reliability of the biological treatment processes by excluding potentially toxic levels of pollutants from the sewer system. Planning a reuse system for a WWTF Figure 3-9.

One of the most critical objectives in any reuse program is to ensure that public health protection is not compromised through the use of reclaimed water. To date there have not been any confirmed cases of infectious disease resulting from the use of properly treated reclaimed water in the U.S. Other objectives, such as preventing environmental degradation, avoiding public nuisance, and meeting user requirements, must also be satisfied, but the starting point remains the safe delivery and use of properly treated reclaimed water. Protection of public health is achieved by: (1) reducing or eliminating concentrations of pathogenic bacteria, parasites, and enteric viruses in the reclaimed water, (2) controlling chemical constituents in reclaimed water, and/ or (3) limiting public exposure (contact, inhalation, ingestion) to reclaimed water. Reclaimed water projects may vary significantly in the level of human exposure incurred, with a corresponding variation in the potential for health risks. Where human exposure is likely in a reuse application, reclaimed water should be treated to a high degree prior to its use. Conversely, where public access to

Reclaimed Water Supply vs. Irrigation Demand


a reuse site can be restricted so that exposure is unlikely, a lower level of treatment may be satisfactory, provided that worker safety is not compromised. Determining the necessary treatment for the intended reuse application requires an understanding of the:
„ Constituents of concern in wastewater „ Levels of treatment and processes applicable for re-

Reclaimed water quality standards have evolved over a long period of time, based on both scientific studies and practical experience. Chapter 4 provides a summary of state requirements for different types of reuse projects. While requirements might be similar from state to state, allowable concentrations and the constituents monitored are state-specific. Chapter 4 also provides suggested guidelines for reclaimed water quality as a function of use.

ducing these constituents to levels that achieve the desired reclaimed water quality

Which treatment processes are needed to achieve the required reclaimed water quality? While it must be acknowledged that raw wastewater may pose a significant risk to public health, it is equally important to point out that current treatment technologies allow water to be treated to almost any quality desired. For many uses of reclaimed water, appropriate water quality can be achieved through conventional, widely practiced treatment processes. Advanced treatment beyond secondary treatment may be required as the level of human contact increases.


Health Assessment of Water Reuse

The types and concentrations of pathogenic organisms found in raw wastewater are a reflection of the enteric organisms present in the customer base of the collection system. Chemical pollutants of concern may also be present in untreated wastewater. These chemicals may originate from any customer with access to the collection system, but are typically associated with industrial customers. Recent studies have shown that over-the-counter and prescription drugs are often found in wastewater. The ability for waterborne organisms to cause disease is well established. Our knowledge of the hazards of chemical pollutants varies. In most cases, these concerns are based on the potential that adverse health effects may occur due to long-term exposure to relatively low concentrations. In addition, chemicals capable of mimicking hormones have been shown to disrupt the endocrine systems of aquatic animals. In order to put these concerns into perspective with respect to water reclamation, it is important to consider the following questions.

„ Which sampling/monitoring protocols are required to

ensure that water quality objectives are being met? As with any process, wastewater reuse programs must be monitored to confirm that they are operating as expected. Once a unit process is selected, there are typically standard Quality Assurance/Quality Control (QA/QC) practices to assure that the system is functioning as designed. Reuse projects will often require additional monitoring to prevent the discharge of substandard water to the reclamation system. On-line, real-time water quality monitoring is typically used for this purpose. Mechanism of Disease Transmission

What is the intended use of the reclaimed water? Consideration should be given to the expected degree of human contact with the reclaimed water. It is reasonable to assume that reclaimed water used for the irrigation of non-food crops on a restricted agricultural site may be of lesser quality than water used for landscape irrigation at a public park or school, which in turn may be of a lesser quality than reclaimed water intended to augment potable supplies.

„ Given the intended use of reclaimed water, what con-

centrations of microbiological organisms and chemicals of concern are acceptable?

For the purposes of this discussion, the definition of disease is limited to illness caused by microorganisms. Health issues associated with chemical constituents in reclaimed water are discussed in Section Diseases associated with microorganisms can be transmitted by water to humans either directly by ingestion, inhalation, or skin contact of infectious agents, or indirectly by contact with objects or individuals previously contaminated. The following circumstances must occur for an individual to become infected through exposure to reclaimed water: (a) the infectious agent must be present in the community and, hence, in the wastewater from that community; (b) the agents must survive, to a significant degree, all of the wastewater treatment processes to which they are exposed; (c) the individual


must either directly or indirectly come into contact with the reclaimed water; and (d) the agents must be present in sufficient numbers to cause infection at the time of contact. The primary means of ensuring reclaimed water can be used for beneficial purposes is first to provide the appropriate treatment to reduce or eliminate pathogens. Treatment processes typically employed in water reclamation systems are discussed below and in Section 3.4.2. Additional safeguards are provided by reducing the level of contact with reclaimed water. Section 3.6 discusses a variety of cross-connection control measures that typically accompany reuse systems. The large variety of pathogenic microorganisms that may be present in raw domestic wastewater is derived principally from the feces of infected humans and primarily transmitted by consumption. Thus, the main transmission route is referred to as the “fecal-oral” route. Contaminated water is an important conduit for fecal-oral transmission to humans and occurs either by direct consumption or by the use of contaminated water in agriculture and food processing. There are occasions when host infections cause passage of pathogens in urine. The 3 principal infections leading to significant appearance of pathogens in urine are: urinary schistosomiasis, typhoid fever, and leptospirosis. Coliform and other bacteria may be numerous in urine during urinary tract infections. Since the incidence of these diseases in the U.S. is very low, they constitute little public health risk in water reuse. Microbial agents resulting from venereal infections can also be present in urine, but they are so vulnerable to conditions outside the body that wastewater is not a predominant vehicle of transmission (Feachem et al., 1983 and Riggs, 1989). Pathogenic Microorganisms and Health Risks

Most of the organisms found in untreated wastewater are known as enteric organisms; they inhabit the intestinal tract where they can cause disease, such as diarrhea. Table 3-2 lists many of the infectious agents potentially present in raw domestic wastewater. These microbes can be classified into 3 broad groups: bacteria, parasites (parasitic protozoa and helminths), and viruses. Table 3-2 also lists the diseases associated with each organism. a. Bacteria

Bacteria are microscopic organisms ranging from approximately 0.2 to 10 µm in length. They are distributed ubiquitously in nature and have a wide variety of nutritional requirements. Many types of harmless bacteria colonize in the human intestinal tract and are routinely shed in the feces. Pathogenic bacteria are also present in the feces of infected individuals. Therefore, municipal wastewater can contain a wide variety and concentration range of bacteria, including those pathogenic to humans. The numbers and types of these agents are a function of their prevalence in the animal and human community from which the wastewater is derived. Three of the more common bacterial pathogens found in raw wastewater are Salmonella sp, Shigella sp. and enteropathogenic Escherichia coli which have caused drinking water outbreaks with significant numbers of cases of hemolytic uremic syndrome (HUS) and multiple deaths (e.g. Walkerton, Ontario; Washington County, NY; Cabool, MO; Alpine, WY). Bacterial levels in wastewater can be significantly lowered through either a “removal” or an “inactivation” process. The removal process involves the physical separation of the bacteria from the wastewater through sedimentation and/or filtration. Due to density considerations, bacteria do not settle as individual cells or even colonies. Typically, bacteria can adsorb to particulate matter or floc particles. These particles settle during sedimentation, secondary clarification, or during an advanced treatment process such as coagulation/flocculation/sedimentation using a coagulant. Bacteria can also be removed by using a filtration process that includes sand filters, disk (cloth) filters, or membrane processes. Filtration efficiency for a sand or cloth filter is dependent upon the effective pore size of the filtering medium and the presence of a “pre-coat” layer, usually other particulate matter. Because the pore sizes inherent to microfiltration and ultrafiltration membranes (including those membranes used in membrane bioreactors), bacteria are, to a large extent, completely removed due to size exclusion. Ultimately, the sedimented or filtered bacteria are removed from the overall treatment system through the sludge and backwash treatment system.

The potential transmission of infectious disease by pathogenic agents is the most common concern associated with reuse of treated municipal wastewater. Fortunately, sanitary engineering and preventive medical practices have combined to reach a point where waterborne disease outbreaks of epidemic proportions have, to a great extent, been controlled. However, the potential for disease transmission through water has not been eliminated. With few exceptions, the disease organisms of epidemic history are still present in today’s sewage. The level of treatment today is more related to severing the transmission chain than to fully eradicating the disease agents. Many infectious disease microbes affecting individuals in a community can find their way into municipal sewage.


Table 3-2.

Infectious Agents Potentially Present in Untreated Domestic Wastewater
Pathoge n Dis e as e Shigellos is (bac illary dy s entery ) Ty phoid fev er Salmonellos is Cholera G as troenteritis and s eptic emia, hemoly tic uremic s y ndrome (HUS) Yers inios is Leptos piros is G as troenteritis , reac tiv e arthritis Amebias is (amebic dy s entery ) G iardias is (gas troenteritis ) Cry ptos poridios is , diarrhea, fev er Diarrhea As c arias is (roundw orm infec tion) Ancy lostomiasis (hook worm infection) Nec atorias is (roundworm infec tion) Cutaneous larv a migrams (hook worm infec tion) Strongy loidias is (threadworm infection) Tric hurias is (whipw orm infec tion) Taenias is (tapeworm infec tion) Enterobias is (pinwork infec tion) Hy datidos is (tapeworm infec tion) G as troenteritis , heart anomolies , meningitis , others Infec tious hepatitis Res piratory dis eas e, ey e infec tions , gas troenteritis (serotype 40 and 41) G as troenteritis G as troenteritis Diarrhea, vomiting, fev er G as troenteritis G as troenter itis G as troenteritis

Bac teria Shigella ( s pp.) Salmonella typhi Salmonella (1700 s eroty pes s pp.) Vib ro c holerae Es c heric hia c oli (enteropathogenic ) Yers inia enteroc olitic a Leptos pira (s pp.) Campylob ac ter jejune Protoz oa Entamoeb a his tolytic a G iardia lamb lia Cryptos poridium Mic ros poridia Helminths As c aris lumb ric oides Anc ylos toma (s pp) Nec ator americ anus Anc ylos toma (s pp.) Strongloides s terc oralis Tric huris tric hiura Taenia (s pp.) Enterob ius vermic ularis Ec hinoc oc c us granulos us (s pp.) Virus es Enteroviruses (polio, echo, coxsackie, new enterovirus es, serotype 68 to 71) Hepatitis A and E v irus Adenov irus Rotav irus Parv ov irus Noroviruses As trov irus C alic iv irus Coronav irus

Source: Adapted from National Research Council, 1996; Sagik et. al., 1978; and Hurst et. al., 1989 Inactivation of bacteria refers to the destruction (death) of bacteria cells or the interference with reproductive ability using a chemical or energy agent. Such inactivation is usually referred to as disinfection. The most common disinfectants used in wastewater treatment are free chlorine, chloramines, ultraviolet (UV) light, and ozone. Chlorine, a powerful chemical oxidant, generally inactivates bacterial cells by causing physiological damage to cell membranes and damage to the internal cell components. Chloramines, chlorine substituted ammonia compounds, generally inactivate bacteria cells by disrupting DNA, thus causing direct cell death and/or inhibiting ability to reproduce. UV light also inactivates bacteria by damaging the DNA, thus inhibiting the ability to reproduce. Ozone, another powerful oxidant, can cause cell inactivation by direct damage to the cell wall and membrane, disruption of enzymatic reaction, and damage to DNA. The relative effectiveness of each chemical disinfectant is generally related to the product of disinfectant concentration and the disinfectant contact time. This prod-


uct is commonly referenced as the “Ct” value. Tables of various Ct values required to inactivate bacteria (and other pathogens, such as viruses and protozoans) are readily available in the literature for clean (filtered) water applications. These Ct values are a function of temperature, pH, and the desired level of inactivation. In recognition of the many constraints associated with analyzing wastewater for all of the potential pathogens that may be present, it has been common practice to use a microbial indicator or surrogate to indicate fecal contamination of water. Some bacteria of the coliform group have long been considered the prime indicators of fecal contamination and are the most frequently applied indicators used by state regulatory agencies to monitor water quality. The coliform group is composed of a number of bacteria that have common metabolic attributes. The total coliform groups are all gram-negative aspogenous rods, and most are found in feces of warm-blooded animals and in soil. Fecal coliforms are, for the most part, bacteria restricted to the intestinal tract of warm-blooded animals and comprise a portion of the total coliform group. Coliform organisms are used as indicators because they occur naturally in the feces of warm-blooded animals in higher concentrations than pathogens, are easily detectable, exhibit a positive correlation with fecal contamination, and generally respond similarly to environmental conditions and treatment processes as many bacterial pathogens. Where low levels of coliform organisms are used to indicate the absence of pathogenic bacteria, there is consensus among microbiologists that the total coliform analysis is not superior to the fecal coliform analysis. Specific methods have been developed to detect and enumerate Escherichia coli for use as a potential indicator organism. b. Parasitic Protozoa and Helminths

There are several helminthic parasites that occur in wastewater. Examples include the roundworm Ascaris as well as other nematodes such as the hookworms and pinworm. Many of the helminths have complex life cycles, including a required stage in intermediate hosts. The infective stage of some helminths is either the adult organism or larvae, while the eggs or ova of other helminths constitute the infective stage of the organisms. The eggs and larvae, which range in size from about 10 µm to more than 100 µm, are resistant to environmental stresses and may survive usual wastewater disinfection procedures. Helminth ova are readily removed by commonly used wastewater treatment processes such as sedimentation, filtration, or stabilization ponds. A 1992 study in St. Petersburg, Florida, showed helminths were completely removed in the secondary clarifiers (Rose and Carnahan, 1992). In recent years, the protozoan parasites have emerged as a significant human health threat in regards to chlorinated drinking water. In particular, the protozoa such as Giardia lamblia , Cryptosporidium pavum , and Cyclospora cayetanensis have caused numerous waterborne and/or foodborne outbreaks. Microsporidia spp. have also been implicated as a waterborne pathogen (Cotte et al., 1999). Protozoan pathogens can be reduced in wastewater by the same previously described mechanisms of removal and inactivation. Cryptosporidium oocysts are 4 to 6 mm in diameter while Giardia cysts range between 8 to 16 mm in diameter. Due to the relatively large size compared to bacteria, the protozoa can be removed by properly designed and operated sedimentation and filtration systems commonly employed in wastewater and water treatment. In terms of inactivation, commonly used disinfectants such as chlorine are not as effective for inactivating the protozoa as compared to bacteria and viruses. Table 3-3 shows the relative microbial resistance to disinfection compared to E. coli. For the chemical disinfectants, a higher Ct value is required to show an equal level of inactivation as compared to bacteria. Advanced disinfection using irradiation such as UV or electron beam treatments have been shown to be effective for inactivating the pathogens with the necessary fluence or dose being roughly equivalent to that required by some bacteria. c. Viruses

The most common parasites in domestic untreated wastewater include several genera in the microspora, protozoa, trematode, and nematode families. Since the parasites cannot multiply in the environment, they require a host to reproduce and are excreted in the feces as spores, cysts, oocysts, or eggs, which are robust and resistant to environmental stresses such as dessication, heat, and sunlight. Most parasite spores, cysts, oocysts, and eggs are larger than bacteria and range in size from 1 µm to over 60 µm. While these parasites can be present in the feces of infected individuals who exhibit disease symptoms, carriers with unapparent infections can also excrete them, as may be the case with bacteria and viral infections as well. Furthermore, some protozoa such as Toxoplasma and Cryptosporidium are among the most common opportunistic infections in patients with acquired immunodeficiency syndrome (AIDS) (Slifko et al., 2000).

Viruses are obligate intracellular parasites able to multiply only within a host cell and are host-specific. Viruses occur in various shapes and range in size from 0.01 to 0.3 µm in cross-section and are composed of a nucleic acid core surrounded by an outer coat of protein. Bacte-


riophage are viruses that infect bacteria as the host; they have not been implicated in human infections and are often used as indicators in seeded virus studies. Coliphages are host specific viruses that infect the coliform bacteria. Enteric viruses multiply in the intestinal tract and are released in the fecal matter of infected persons. Not all types of enteric viruses have been determined to cause waterborne disease, but over 100 different enteric viruses are capable of producing infections or disease. In general, viruses are more resistant to environmental stresses than many of the bacteria, although some viruses persist for only a short time in wastewater. The Enteroviruses, Rotavirus, and the Enteric Adenoviruses, which are known to cause respiratory illness, gastroenteritis, and eye infections, have been isolated from wastewater. Of the viruses that cause diarrheal disease, only the Noroviruss and Rotavirus have been shown to be major waterborne pathogens (Rose, 1986) capable of causing large outbreaks of disease. There is no evidence that the Human Immunodeficiency Virus (HIV), the pathogen that causes AIDS, can be transmitted via a waterborne route (Riggs, 1989). The results of one laboratory study (Casson et al., 1992), where primary and undisinfected secondary effluent samples were inoculated with HIV (Strain IIIB) and held for up to 48 hours at 25° C (77° F), indicated that HIV survival was significantly less than Polio virus survival under similar conditions. A similar study by Casson et al. in 1997 indicated that untreated wastewater spiked with blood cells infected with the HIV exhibited a rapid loss of HIV, although a small fraction remained stable for 48 hours. Similar to bacteria and protozoan parasites, viruses can be both physically removed from the wastewater or inactivated. However, due to the relatively small size of typical viruses, the sedimentation and filtration processes

are less effective at removal. Significant virus removal can be achieved with ultrafiltration membranes, possibly in the 3- to 4-log range. However, for viruses, inactivation is generally considered the more important of the 2 main reduction methods. Due to the size and relatively noncomplex nature of viruses, most disinfectants demonstrate reasonable inactivation levels at relatively low Ct values. Interestingly, for UV light disinfection, relatively high fluence values are required to inactivate viruses when compared to bacteria and protozoans. It is believed that the protein coat of the virus shields the ribonucleic acid (RNA) from UV light. a. Presence Bacteria, viruses, and parasites can all be detected in wastewater. Studies of pathogens have reported average levels of 6.2, 5.8, and 5.3 log cfu/100ml of Yersinia, Shigella, and Salmonella detected in primary-clarified sewage influent over a 2-year period in a U.S. facility (Hench et al., 2003). Salmonella may be present in concentrations up to 10,000/l. The excretion of Salmonella typhi by asymptomatic carriers may vary from 5 x 103 to 45 x 106 bacteria/g of feces. But there are few studies in recent years, which have directly investigated the presence of bacterial pathogens and have focused more often on the indicator bacteria. Concentrations excreted by infected individuals range from 106 cysts, 107 oocysts and as high as 1012 virus particle per gram of feces for Giardia, Cryptosporidium, and Rotavirus, respectively (Gerba, 2000). Pathogen levels in wastewater can vary depending on infection in the community. Levels of viruses, parasites, and indicator bacteria reported in untreated and secondary treated effluents are shown in Tables 3-4 and 3-5. These tables illustrate the tremendous range in the concentrations of microorganPresence and Survival of Pathogens

Table 3-3.

Ct Requirements for Free Chlorine and Chlorine Dioxide to Achieve 99 Percent Inactivation of E. Coli Compared to Other Microorganisms
% Greater Cl2 Ct Requirement Compared to E. Coli NA 96% 196-199% >200% % Greater Chloramine Ct Requirement Compared to E. Coli NA 170% 117-135% >194%

Microbe E. Coli Poliovirus Giardia Cryptosporidium

Cl2 Ct 0.6 1.7 54-250 >7,200

Chloramine Ct 113 1,420 430-580 >7,200

Adapted from: Maier, 2000


isms that may be found in raw and secondary wastewater. The methods currently used to detect Cryptosporidium oocysts and Giardia cysts are limited since they cannot assess viability or potential infectivity. Therefore, the health risks associated with finding oocysts and cysts in the environment cannot be accurately ascertained from occurrence data and the risks remain unknown. Dowd et al. (1998) described a polymerase chain reaction (PCR) method to detect and identify the microsporidia (amplifying the small subunit ribosomal DNA of microsporidia). They found isolates in sewage, surface waters, and ground waters. The strain that was most often detected was Enterocytozoon bieneusi, which is a cause of diarrhea and excreted from infected individuals into wastewater. Microsporidia spores have been shown to be stable in the environment and remain infective for days to weeks outside their hosts (Shadduck, 1989; Waller, 1980; Shadduck and Polley, 1978). Because of their small size (1 to 5 µm), they may be difficult to remove using conventional filtration techniques. However, initial studies using cell culture suggest that the spores may be more susceptible to disinfection (Wolk et al., 2000). Under experimental conditions, absorption of viruses and E. coli through plant roots, and subsequent acropetal translocation has been reported (Murphy and Syverton, 1958). For example, one study inoculated soil with Polio virus, and found that the viruses were detected in the leaves of plants only when the plant roots were damaged or cut. The likelihood of translocation of pathogens through trees or vines to the edible portions of crops is extremely low, and the health risks are negligible.

Table 3-5.

Microorganism Concentrations in Secondary Non-Disinfected Wastewater
Average Concentrations (CFU, PFU, or Cysts/Oocysts per 100L) 7,764 2,186 20 to 650 5 to 2,297 140

Organism Fecal Coliforms Enterococci Enteric virus Giardia cysts Cryptosporidium oocysts

Source: NRC, 1998 b. Survival Most pathogens do not increase in numbers outside of their host, although in some instances the ova of helminths do not mature to the larval stage until they are in the soil. In all cases, the numbers decrease at various rates, depending on a number of factors including the inherent biologic nature of the agent, temperature, pH, sunlight, relative humidity, and competing flora and fauna. Examples of relative survival times for some pathogens are given in Table 3-6. These values are intended to indicate relative survival rates only, and illustrate the various persistence of selected organisms. Pathogens and Indicator Organisms in Reclaimed Water

Table 3-4.

Microorganism Concentrations in Raw Wastewater
Range in Average Concentrations (CFU, PFU or Cysts/Oocysts) 105 to 105 10 4 to 10 5 1 to 10 3 10 2 to 10 4 1 to 10

Organism Fecal Coliforms/100L Enterococi/100L Shigella /100mL Salm onella /100mL Helminth ova/100mL Enteric virus/100L Giardia cysts/100L Cryptosporidium oocysts/100L

There have been a number of studies regarding the presence of pathogens and indicator organisms in reclaimed water and such studies continue as experience in this field expands. Koivunen et al. (2003) compared the reduction of fecal coliforms to the reduction of Salmonella by conventional biological treatment, filtration, and disinfection. Fecal coliform bacteria were present at 1000fold greater concentration, and the Salmonella bacteria were reduced to non-detectable levels by advanced treatment (greater than 99.9 percent). Fecal coliform bacteria were a good, conservative indicator of such reductions. However, given the numbers of Salmonellae in secondary effluents and the fact that 18 carried multiple antibiotic resistance, the authors concluded that without proper additional advanced treatment, there may be a significant public health risk. A year-long study investigated a conventional reuse treatment facility in St. Petersburg, Florida (Rose et al., 1996). In this facility, deep-bed sand filtration and disinfection, with total chlorine residual (4 to 5 mg/L) were the barriers assessed through both monitoring of naturally occurring bacteria, protozoa, and viruses, as well as through seeded challenge studies. Removals were 5 log for human vi-

1 to 5 x10 3 0.39 to 4.9x10 4 0.2 to 1.5 x10 3

Source: NRC, 1998 and Maier et. al., 2000


Table 3-6.

Typical Pathogen Survival Times at 20-30 oC
Survival Time (days) Fresh Water & Sewage <120 but usually <50
a,c a

Pathogen Viruses

Crops <60 but usually <15 <30 but usually <15 <30 but usually <15 <10 but usually <5 <5 but usually <2

Soil <100 but usually <20 <70 but usually <20 <70 but usually <20

Enterovirusesb Bacteria Fecal coliforms
a Shigella spp.

<60 but usually <30 <60 but usually <30 <30 but usually <10 <30 but usually <10

Salmonella spp.

--<20 but usually <10

Vibrio cholerae Protozoa

Entamoeba histolytica cysts Helminths Ascaris lumbricoides eggs

<30 but usually <15

<10 but usually <2

<20 but usually <10

Many months

<60 but usually <30

Many months

a b c d

In seawater, viral survival is less and bacterial survival is very much less, than in fresh water. Includes polio-, echo-, and coxsackieviruses Fecal coliform is not a pathogen but is often used as an indicator organism V. cholerae survival in aqueous environments is a subject of current uncertainty.

Source: Adapted from Feacham et. al., 1983 ruses and coliphage indicators, with anywhere from 1.5 to 3 log reductions by disinfection. A 3 log reduction for protozoa was achieved and greater than 1 log reduction was achieved for bacteria and indicators. Protozoan viability was not evaluated. In this study, Enterococci and Clostridium were not included as alternative indicators. Only the phage was used as a virus indicator. Seeded trials using bacteriophage demonstrated a 1.5 and 1.6 log reduction by filtration and disinfection, respectively. A second study was done at the Upper Occoquan Sewage Authority (UOSA) in Fairfax County, Virginia. Samples were collected once per month for 1 year from 8 sites from the advanced wastewater reclamation plant (Rose et al., 2000). The 8 sites were monitored for indicator bacteria, total and fecal coliforms, enterococci, Clostridium, coliphage (viruses which infect E.coli), human enteric viruses, and enteric protozoa. Multimedia filtration reduced the bacteria by approximately 90 percent, but did not effectively reduce the coliphage or enteroviruses. The enteric protozoa were reduced by 85 to 95.7 percent. Chemical lime treatment was the most efficient barrier to the passage of microorganisms (reducing these microorganisms by approximately 99.99 percent for bacteria, 99.9 percent for Clostridium and enteroviruses, and 99 percent for protozoa). Disinfection was achieved through chlorination (free chlorine residuals of 0.2 to 0.5 mg/l), and effectively achieved another 90 to 99 percent reduction. Overall, the plant was able to achieve a 5 to 7 log reduction of bacteria, 5 log reduction of enteroviruses, 4 log reduction of Clostridium, and 3.5 log reduction of protozoa. Total coliforms, enterococci, Clostridium, coliphage, Cryptosporidium, and Giardia were detected in 4 or fewer samples of the final effluent. No enteroviruses or fecal coliforms were detected. Protozoa appeared to remain the most resistant microorganisms found in wastewater. However, as with the St. Petersburg study, protozoan viability in these studies was not addressed. Table 3-7 provides a summary of influent and effluent microbiological quality for the St. Petersburg and Upper Occaquan studies for enterovirus, Cryptosporidium, and Giardia. Enteroviruses were found 100 percent of the time in untreated wastewater. The enteric protozoa, Cryptosporidium, and Giardia were found from 67 to 100 percent of the time in untreated wastewater. Giardia cysts were found to be more prevalent, and at higher concentrations than oocysts in wastewater, perhaps due to the increased incidence of infection in populations compared to cryptosporidiosis and higher asymptomatic infections. Levels of oocysts in sewage are similar throughout the world (Smith and Rose, 1998). However, crops irrigated with wastewater of a poorer quality in


Table 3-7

Pathogens in Untreated and Treated Wastewater
Organism Enterovirus (PFU/100l) Untreated W astew ater % Positive 100 67 100 100 100 100 Average Value 1,033 1,456 6,890 1,100 1,500 49,000 Reclaim ed W ater % Positive 8 17 25 0 8.3 17 Average Value 0.01 0.75 0.49 0 0.037 1.1

St. Petersburg, FL

Cryptosporidium (oocysts/100l) Giardia (cysts/100l) Enterovirus (PFU/100l)

Upper Occoquan, VA Cryptosporidium (oocysts/100l) Giardia (cysts/100l)

Source: Walker-Coleman et. al., 2002; Rose and Carnahan, 1992; Sheikh and Cooper, 1998; Rose et. al., 2001; Rose and Quintero-Betancourt, 2002; and York et. al., 2002 Israel contained more oocysts than cysts (Armon et al., 2002). The results of these studies indicate that the treatment processes employed are capable of significantly reducing or eliminating these pathogens. The State of Florida recognizes that Giardia and Cryptosporidium are pathogens of increasing importance to water reclamation and now requires monitoring for these pathogens (Florida DEP, 1999). Results of this monitoring are presented in Table 3-8. The Florida facilities highlighted in this table generally feature secondary treatment, filtration, and high-level disinfection. Table 3-9 includes the associated data from these facilities for TSS, turbidity, and total chlorine residual. Visual inspection studies in Florida and elsewhere routinely found Giardia cysts and Cryptosporidium oocysts in reclaimed water that received filtration and high-level disinfection and was deemed suitable for public access uses. A number of more detailed studies which considered the viability and infectivity of the cysts and oocysts suggested that Giardia was likely inactivated by chlorine but 15 to 40 percent of detected Cryptosporidium oocysts may survive (Keller, 2002; Sheikh, 1999; Garcia, 2002; Genacarro, 2003; Quintero, 2003). Other studies evaluating UV and the electron beam as alternatives to chlorine disinfection found that both parasites were easily inactivated (Mofidi 2002 and Slifko 2001). Both Giardia cysts and Cryptosporidium oocysts required less than 10mJ/cm2 for complete inactivation by UV (Mofidi 2002 and Slifko 2001). In December 2003, the Water Environment Research Foundation (WERF) initiated a series of workshops on indicators for pathogens in wastewater, stormwater, and biosolids. The first workshop considered the state of science for indicator organisms. Potential indicators for further study were identified in an attempt to improve upon current indicator organism use and requirements. The results of this effort are summarized in Table 3-10. Subsequent phases of this effort will evaluate the usefulness of the selected list of indicators and compare them with current indicators. Detailed studies will then be conducted using the most promising indicators in field studies at various sites in the U.S. Aerosols

Aerosols are defined as particles less than 50 µm in diameter that are suspended in air. Viruses and most pathogenic bacteria are in the respirable size range; hence, the inhalation of aerosols is a possible direct mean of human infection. Aerosols are most often a concern where reclaimed water is applied to urban or agricultural sites with sprinkler irrigation systems, or where it is used for cooling water make-up. The concentration of pathogens in aerosols is a function of their concentration in the applied water and the aerosolization efficiency of the spray process. During spray irrigation, the amount of water that is aerosolized can vary from less than 0.1 percent to almost 2 percent, with a mean aerosolization efficiency of 1 percent or less. Infection or disease may be contracted indirectly by deposited aerosols on surfaces such as food, vegetation, and clothes. The infective dose of some pathogens is lower for respiratory tract infections than for infections via the gastrointestinal tract. Therefore, for some pathogens, inhalation may be a more likely route for disease transmission than either contact or ingestion. The infectivity of an inhaled aerosol depends on the depth of the respiratory penetration and the presence of pathogenic organisms capable of infecting the respiratory sys-


Table 3-8.

Summary of Florida Pathogen Monitoring Data
Statistic Number of observations % having detectable concentrations 25 percentile (#/100 l) 50 percentile (#/100 l) 75 percentile (#/100 l) 90 percentile (#/100 l) Maximum (#/100 l) Giardia 69 58% ND 4 76 333 3,096 Cryptosporidium 68 22% ND ND ND 2.3 282

Notes: (a) All numeric data are total numbers of cysts or oocysts per 100 L. (b) ND indicates a value less than detection. Source: Walker-Coleman, et. al., 2002.

Table 3-9.

Operational Data for Florida Facilities
Statistic Minimum 10 percentile 25 percentile 50 percentile 75 percentile 90 percentile Maximum TSS (mg/l) 0.19 0.4 0.8 1 1.76 2.1 6 Turbidity (NTU) 0.31 0.45 0.65 0.99 1.36 1.8 4.5 Chlorine Residual (mg/l) 1.01 1.9 2.32 4.1 5 7.1 10.67

Source: Walker-Coleman et. al., 2002

tem. Aerosols in the 2 to 5 µm size range are generally excluded from the respiratory tract, with some that are subsequently swallowed. Thus, if gastrointestinal pathogens are present, infection could result. A considerably greater potential for infection occurs when respiratory pathogens are inhaled in aerosols smaller than 2 µm in size, which pass directly to the alveoli of the lungs (Sorber and Guter, 1975). One of the most comprehensive aerosol studies, the Lubbock Infection Surveillance Study (Camann et al., 1986), monitored viral and bacterial infections in a mostly rural community surrounding a spray injection site near Wilson, Texas. The source of the irrigation water was undisinfected trickling filter effluent from the Lubbock Southeast water reclamation plant. Spray irrigation of the wastewater significantly elevated air densities of fecal coliforms, fecal streptococci, mycobacteria, and coliphage above the ambient background levels for at least 650 feet (200 meters) downwind. The geometric

mean concentration of enteroviruses recovered 150 to 200 feet (44 to 60 meters) downwind was 0.05 pfu/m3, a level higher than that observed at other wastewater aerosol sites in the U.S. and in Israel (Camann et al., 1988). While disease surveillance found no obvious connection between the self-reporting of acute illness and the degree of aerosol exposure, serological testing of blood samples indicated that the rate of viral infections was slightly higher among members of the study population who had a high degree of aerosol exposure (Camann et al., 1986). For intermittent spraying of disinfected reclaimed water, occasional inadvertent contact should pose little health hazard from inhalation. Cooling towers issue aerosols continuously, and may present a greater concern if the water is not properly disinfected. Although a great deal of effort has been expended to quantify the numbers of fecal coliforms and enteric pathogens in cooling tower waters, there is no evidence that they occur in large num-


Table 3-10

Some Suggested Alternative Indicators for Use in Monitoring Programs
Param e te r Pathoge n Pre s e nce F+ RNA coliphages Viruses Somatic coliphages Adenovirus JC virus E. coli Bacteria Enterococci Bifidob acteria Clostridium perfringens Parasites Non-microbial indicators Pathogens as possible indicators Sulfite reducing Clostridium spp. Fecal sterols Cryptosporidium Giardia

Source: WERF Workshop, 2003

bers, although the numbers of other bacteria may be quite large (Adams and Lewis, n.d.). No documented disease outbreaks have resulted from the spray irrigation of disinfected, reclaimed water. Studies indicate that the health risk associated with aerosols from spray irrigation sites using reclaimed water is low (U.S. EPA, 1980b). However, until more sensitive and definitive studies are conducted to fully evaluate the ability of pathogens contained in aerosols to cause disease, the general practice is to limit exposure to aerosols produced from reclaimed water that is not highly disinfected. Exposure is limited through design or operational controls. Design features include:
„ Setback distances, which are sometimes called buffer

„ Not spraying when wind is blowing toward sensitive

areas subject to aerosol drift or windblown spray
„ Irrigating at off-hours, when the public or employees

would not be in areas subject to aerosols or spray All these steps would be considered part of a best management plan for irrigation systems regardless of the source of water used. Most states with reuse regulations or guidelines include setback distances from spray areas to property lines, buildings, and public access areas. Although predictive models have been developed to estimate microorganism concentrations in aerosols or larger water droplets resulting from spray irrigation, setback distances are determined by regulatory agencies in a somewhat arbitrary manner, using levels of disinfection, experience, and engineering judgment as the basis. Infectious Disease Incidence Related to Wastewater Reuse


Windbreaks, such as trees or walls around irrigated areas with large orifices to reduce the formation of fine mist

„ Low pressure irrigation systems and/or spray nozzles

„ Low-profile sprinklers „

Surface or subsurface methods of irrigation

Operational measures include:

Spraying only during periods of low wind velocity

Epidemiological investigations have focused on wastewater-contaminated drinking water supplies, the use of raw or minimally-treated wastewater for food crop irrigation, health effects to farm workers who routinely contact poorly treated wastewater used for irrigation, and the health effects of aerosols or windblown spray emanating from spray irrigation sites using undisinfected wastewater. These investigations have all provided evidence of infectious disease transmission from such prac-


tices (Lund, 1980; Feachem et al., 1983; Shuval et al., 1986). Review of the scientific literature, excluding the use of raw sewage or primary effluent on sewage farms in the late 19th century, does not indicate that there have been no confirmed cases of infectious disease resulting from reclaimed water use in the U.S. where such use has been in compliance with all appropriate regulatory controls. However, in developing countries, the irrigation of market crops with poorly treated wastewater is a major source of enteric disease (Shuval et al., 1986). Occurrences of low level or endemic waterborne diseases associated with exposure to reclaimed water have been difficult to ascertain for several reasons:
„ Current detection methods have not been sufficiently

framework does not explicitly acknowledge the differences between health effects due to chemical exposure versus those due to microbial exposure. Those differences include acute versus chronic health effects, potential for person-to-person transmission of disease, and the potential need to account for the epidemiological status of the population (Olivieri, 2002). Microbial risk analyses require several assumptions to be made. These assumptions include a minimum infective dose of selected pathogens, concentration of pathogens present, quantity of pathogens ingested, inhaled, or otherwise contacted by humans, and probability of infection based on infectivity models. The use of microbial risk assessment models have been used extensively by the U.S. Department of Agriculture (USDA) to evaluate food safety for pathogens such as Listeria Monocytogenes in ready to eat foods (USDA, n.d.). The World Health Organization (WHO) and Food and Agriculture Organization (FAO) also provide risk assessment methodologies for use in evaluating food safety (Codex Alimentarius). In order to assess health risks associated with the use of reclaimed water, pathogen risk assessment models to assess health risks associated with the use of reclaimed water have been used as a tool in assessing relative health risks from microorganisms in drinking water (Cooper et al., 1986; Gerba and Haas, 1988; Olivieri et al., 1986; Regli et al., 1991; Rose et al., 1991; Gale, 2002) and reclaimed water (Asano and Sakaji, 1990; EOA, Inc., 1995; Rose and Gerba, 1991; Tanaka et al., 1998; Patterson et al., 2001). Most of the models calculated the probability of individual infection or disease as a result of a single exposure. One of the more sophisticated models calculates a distribution of risk over the population by utilizing epidemiological data such as incubation period, immune status, duration of disease, rate of symptomatic development, and exposure data such as processes affecting pathogen concentration (EOA, Inc., 1995). At the present time, no wastewater disinfection or reclaimed water standards or guidelines in the U.S. are based on risk assessment using microorganism infectivity models. Florida is investigating such an approach and has suggested levels of viruses between 0.04 to 14/ 100 l, depending on the virus (ranging from Rotavirus infectivity to a less infectious virus), viable oocysts at 22/ 100 l, and viable cysts at 5/100 l (York and WalkerColeman, 1999). Microbial risk assessment methodology is a useful tool in assessing relative health risks associated with water reuse. Risk assessment will undoubtedly play a role in future criteria development as epidemiological-based models are improved and refined.

sensitive or specific enough to accurately detect low concentrations of pathogens, such as viruses and protozoa, even in large volumes of water.

Many infections are often not apparent, or go unreported, thus making it difficult to establish the endemicity of such infections. The apparently mild nature of many infections preclude reporting by the patient or the physician. sensitive to detect low-level transmission of these diseases through water.


„ Current epidemiological techniques are not sufficiently


Illness due to enteroviral or parasite infections may not become obvious for several months or years. contact can become a secondary mode of transmission of many pathogens, thereby obscuring the role of water in its transmission.

„ Once introduced into a population, person-to-person

Because of the insensitivity of epidemiological studies to provide a direct empirical assessment of microbial health risk due to low-level exposure to pathogens, methodologies have increasingly relied on indirect measures of risk by using analytical models for estimation of the intensity of human exposure and the probability of human response from the exposure. Microbial risk assessment involves evaluating the likelihood that an adverse health effect may occur from human exposure to one or more potential pathogens. Most microbial risk assessments in the past have used a framework originally developed for chemicals that is defined by 4 major steps: (1) hazard identification, (2) dose-response identification, (3) exposure assessment, and (4) risk characterization. However, this


Chemical Constituents



The chemical constituents potentially present in municipal wastewater are a major concern when reclaimed water is used for potable reuse. These constituents may also affect the acceptability of reclaimed water for other uses, such as food crop irrigation or aquaculture. Potential mechanisms of food crop contamination include:

The organic make-up of raw wastewater includes naturally occurring humic substances, fecal matter, kitchen wastes, liquid detergents, oils, grease, and other substances that, in one way or another, become part of the sewage stream. Industrial and residential wastes may contribute significant quantities of synthetic organic compounds. The need to remove organic constituents is related to the end use of reclaimed water. Some of the adverse effects associated with organic substances include:
„ Aesthetic effects – organics may be malodorous and

Physical contamination, where evaporation and repeated applications may result in a buildup of contaminants on crops Uptake through the roots from the applied water or the soil, although available data indicate that potentially toxic organic pollutants do not enter edible portions of plants that are irrigated with treated municipal wastewater (National Research Council, 1996)


impart color to the water
„ Clogging – particulate matter may clog sprinkler heads

or accumulate in soil and affect permeability
„ Foliar uptake „

With the exception of the possible inhalation of volatile organic compounds (VOCs) from indoor exposure, chemical concerns are less important where reclaimed water is not to be consumed. Chemical constituents are a consideration when reclaimed water percolates into groundwater as a result of irrigation, groundwater recharge, or other uses. These practices are covered in Chapter 2. Some of the inorganic and organic constituents in reclaimed water are listed in Table 3-11. a. Inorganics

Proliferation of microorganisms – organics provide food for microorganisms substances deplete the dissolved oxygen content in streams and lakes. This negatively impacts the aquatic life that depends on the oxygen supply for survival

„ Oxygen consumption – upon decomposition, organic

„ Use limitation – many industrial applications cannot

tolerate water that is high in organic content

In general, the health hazards associated with the ingestion of inorganic constituents, either directly or through food, are well established (U.S. EPA, 1976). EPA has set maximum contaminant levels (MCLs) for drinking water. The concentrations of inorganic constituents in reclaimed water depend mainly on the source of wastewater and the degree of treatment. Residential use of water typically adds about 300 mg/l of dissolved inorganic solids, although the amount added can range from approximately 150 mg/l to more than 500 mg/l (Metcalf & Eddy, 2002). As indicated in Table 3-11 the presence of total dissolved solids, nitrogen, phosphorus, heavy metals, and other inorganic constituents may affect the acceptability of reclaimed water for different reuse applications. Wastewater treatment using existing technology can generally reduce many trace elements to below recommended maximum levels for irrigation and drinking water. Uses in wetlands and recreational surface waters must also consider aquatic life protection and wetland habitat.

Disinfection effects – organic matter can interfere with chlorine, ozone, and ultraviolet disinfection, thereby making them less available for disinfection purposes. Further, chlorination may result in formation of potentially harmful disinfection byproducts organic compounds may result in acute or chronic health effects.

„ Health effects – ingestion of water containing certain

The wide range of anthropogenic organic contaminants in streams influenced by urbanization (including wastewater contamination) includes pharmaceuticals, hormones, antioxidants, plasticizers, solvents, polynuclear aromatic hydrocarbons (PAHs), detergents, pesticides, and their metabolites (Kolpin et al., 2002). The stability and persistence of these compounds are extremely variable in the stream/sediment environment. A recent comprehensive study of the persistence of anthropogenic and natural organic molecules during groundwater recharge suggests that carbamezepine may survive long enough to serve as a useful tracer compound of wastewater origin (Clara et al., 2004).


Table 3-11.

Inorganic and Organic Constituents of Concern in Water Reclamation and Reuse
Cons titue nt Suspended Solids M e as ure d Param e te rs Suspended solids (SS), including volatile and fixed solids Re as ons for Conce r n Organic contaminants, heavy metals, etc. are absorbed on particulates. Suspended matter can shield microorganisms from disinfectants. Excessive amounts of suspended solids cause plugging in irrigation systems. Aesthetic and nuisance problems. Organics provide food for microorganisms, adversely affect disinfection processes, make water unsuitable for some industrial or other uses, consume oxygen, and may result in acute or chronic effects if reclaimed water is u Nitrogen, phosphorus, and potassium are essential nutrients for plant growth and their presence normally enhances the value of the water for irrigation. When discharged to the aquatic environment, nitrogen and phosphorus can lead to the growth of undesir

Biodegradable Organics

Biochemical oxygen demand, chemical oxygen demand, total organic carbon


Nitrogen, Phosphorus, Potassium

Stable Organics

Specific compounds (e.g., pesticides, chlorinated hydrocarbons)

Some of these organics tend to resist conventional methods of wastewater treatment. Some organic compounds are toxic in the environment, and their presence may limit the suitability of reclaimed water for irrigation or other uses. Chlorine reacts with man

Hydrogen Ion Concentration


The pH of wastewater affects disinfection, coagulation, metal solubility, as well as alkalinity of soils. Normal range in municipal wastewater is pH = 6.5 - 8.5, but industrial waste can alter pH significantly. Some heavy metals accumulate in the environment and are toxic to plants and animals. Their presence may limit the suitability of the reclaimed water for irrigation or other uses. Excessive salinity may damage some crops. Specific inorganics electrical conductivity ions such as chloride, sodium, and boron are toxic to specific elements (e.g., in some crops, sodium may pose soil permeability Na, Ca, Mg, Cl, and B problems). Excessive amounts of free available chlorine (>0.05 Chlorine chlorine mg/l) may cause leaf-tip burn and damage some sensitive crops. However, most chlorine in reclaimed water is in a combined form, which does not cause crop damage. Some concerns are expre

Heavy Metals

Specific elements (e.g., Cd, Zn, Ni, and Hg)

Dissolved Inorganics

Total dissolved solids, electrical Conductivity, specific elements (e.g., Na, Ca, Mg, Cl, and B)

Residual Chlorine

Free and combined chlorine

Source: Adapted from Pettygrove and Asano, 1985


The health effects resulting from organic constituents are of primary concern for indirect or direct potable reuse. In addition, these constituents may be of concern where reclaimed water is utilized for food crop irrigation, where reclaimed water from irrigation or other beneficial uses reaches potable groundwater supplies, or where the organics may bioaccumulate in the food chain (e.g., in fish-rearing ponds). Traditional measures of organic matter such as BOD, chemical oxygen demand (COD), and total organic carbon (TOC), are widely used as indicators of treatment efficiency and water quality for many nonpotable uses of reclaimed water. However, these measures have only indirect relevance related to evaluating toxicity and health effects. Sophisticated analytical instrumentation makes it possible to identify and quantify extremely low levels of organic constituents in water. Examples include gas chromatography/tandem mass spectrometry (GC/MS/ MS) or high performance liquid chromatography/mass spectrometry (HPLC/MS). These analyses are costly and may require extensive and difficult sample preparation, particularly for nonvolatile organics. Organic compounds in wastewater can be transformed into chlorinated organic species where chlorine is used for disinfection purposes. In the past, most attention was focused on the trihalomethane (THM) compounds; a family of organic compounds typically occurring as chlorine or bromine-substituted forms of methane. Chloroform, a commonly found THM compound, has been implicated in the development of cancer of the liver and kidney. Improved analytical capabilities to detect extremely low levels of chemical constituents in water have resulted in identification of several health-significant chemicals and disinfection byproducts in recent years. For example, the extremely potent carcinogen, N-nitrosodimethylamine (NDMA) is present in sewage and is produced when municipal wastewater effluent is disinfected with chlorine or chloramines (Mitch et al, 2003). In some situations, the concentration of NDMA present in reclaimed water exceeds action levels set for the protection of human health, even after reverse osmosis treatment. To address concerns associated with NDMA and other trace organics in reclaimed water, several utilities in California have installed UV/H2O2 treatment systems for treatment of reverse osmosis permeate. Quality standards have been established for many inorganic constituents. Treatment and analytical technology has demonstrated the capability to identify, quantify, and control these substances. Similarly, available technology is capable of eliminating pathogenic agents from contaminated waters. On the basis of available information, there is no indication that health risks from using

highly treated reclaimed water for potable purposes are greater than those from using existing water supplies (National Research Council, 1994). Yet, unanswered questions remain about organic constituents, due mainly to their potentially large numbers and unresolved health risk potentials related to long-term, low-level exposure. Assessment of health risks associated with potable reuse is not definitive due to limited chemical and toxicological data and inherent limitations in available epidemiological and toxicological methods. The results of epidemiological studies directed at drinking water have generally been inconclusive, and extrapolation methodologies used in toxicological assessments provide uncertainties in overall risk characterization (National Research Council, 1998). Endocrine Disrupters

In addition to the potential adverse effects of chemicals described in Section, certain chemical constituents present in wastewater also can disrupt hormonal systems. This phenomenon, which is referred to as endocrine disruption, can occur through a variety of mechanisms associated with hormone synthesis, hormone receptor binding, and hormone transformation. As a result of the many mechanisms through which chemicals can impact hormone function, a large number of chemicals are classified as endocrine disrupters. However, the exact types of chemicals that are classified as endocrine disrupters vary among researchers. Table 3-12 highlights a number of example sources of potential endocrine disrupters. For example, the oxyanion, perchlorate, is an endocrine disrupter because it affects the thyroid system (U.S. EPA, 2002). The herbicide, atrazine, is an endocrine disrupter because it affects an enzyme responsible for hormone regulation (Hayes et al. 2002). A USGS project recently sampled 139 streams in 30 states for any 1 of 95 endocrine disrupters. The results indicated that 80 percent of the streams had at least 1 of these compounds (McGovern and McDonald, 2003). The topic of endocrine disruption has significant implications for a wide variety of chemicals used by industry, agriculture, and consumers. As a result, the EPA, the European Union (EU), and other government organizations are currently evaluating approaches for regulating endocrine-disrupting chemicals. With respect to water reuse, the greatest concerns associated with endocrine disruption are related to a series of field and laboratory studies demonstrating that chemicals in wastewater effluent caused male fish to exhibit female characteristics (Purdom et al., 1994; Harries et al., 1996; Harries et al., 1997). This process, which is referred to as feminization, has been attributed mostly to the presence of steroid hormones excreted by humans


(Desbrow et al., 1998 and Snyder et al., 2001). The hormones involved in fish feminization include the endogenous (i.e., produced within the body) hormone 17b-estradiol as well as hormones present in pharmaceuticals (e.g., ethinyl estradiol in birth control pills). Other chemicals capable of feminizing fish are also present in wastewater. These include nonylphenol and alkylphenol polyethoxylates, both of which are metabolites of nonionic detergents formed during secondary wastewater treatment (Ahel et al., 1994). The specific endocrine-disrupting chemicals in reclaimed water can be quantified using modern analytical methods. As indicated previously, the compounds most likely to be responsible for feminization of fish include steroid hormones (e.g., 17b-estradiol and ethinyl estradiol) and detergents metabolites (e.g., nonylphenol and alkylphenol polyethoxylates). Although these compounds cannot be quantified at the levels expected in reclaimed water with the gas chromatography/mass spectrometry (GC/MS) techniques routinely used to quantify priority pollutants, they can be measured with equipment available in many modern laboratories. For the hormones, analytical methods such as gas chromatography/tandem mass spec-

trometry (GC/MS/MS) (Ternes et al., 1999, Huang and Sedlak, 2001), high performance liquid chromatography/ mass spectrometry (HPLC/MS) (Ferguson et al., 2001), or immunoassays (Huang and Sedlak, 2001 and Snyder et al., 2001) are needed to detect the low concentrations present in wastewater effluent (e.g., ethinyl estradiol concentrations are typically less than 2 υg/l in wastewater effluent). Although the endocrine-disrupting detergent metabolites are present at much higher concentrations than the hormones, their analysis also requires specialized analytical methods (Ahel et al., 1994) not available from many commercial laboratories. Bioassays can also be used to quantify the potential of reclaimed water to cause endocrine disruption. These methods are attractive because they have the potential to detect all of the difficult-to-measure endocrine-disrupting chemicals in 1 assay. The simplest bioassays involve in vitro tests, in which a hormone receptor from a mammalian cell is used to detect endocrine-disrupting chemicals. Among the different in vitro assays, the Yeast Estrogen Screen (YES) assay has been employed most frequently (Desbrow et al., 1998). Comparisons between in vitro bioassays and chemical measurements yield

Table 3-12.

Examples of the Types and Sources of Substances that have been Reported as Potential Endocrine-Disrupting Chemicals
Examples of Substances Examples of Uses Examples of Sources incineration and landfill runoff agricultural runoff agricultural runoff harbors industrial and municipal effluents industrial effluent municipal effluents municipal effluents pulp mill effluents

Category Polychlorinated Compounds

polychlorinated dioxins and industrial production of polychlorinated biphenyls byproducts (mostly banned) insecticides (many phased out) pesticides antifoulants on ships surfactants (and their metabolites) plasticisers produced naturally by animals contraceptives present in plant material

Organochlorine Pesticides DDT, dieldrin, and lindane Current Use Pesticides Organotins Alkylphenolics Phthalates Sex Hormones Synthetic Steroids Phytoestrogens atrazine, trifluralin, and permethrin tributyltin nonylphenol and octylphenol dibutyl phthalate and butylbenzyl phthalate 17-beta estradiol and estrone ethinylestradiol isoflavones, lignans, coumestans

Source: Adapted from McGovern and McDonald, 2003 and Berkett and Lester, 2003


consistent results, indicating that steroid hormones are the most significant endocrine disrupting chemicals in wastewater effluent. Unfortunately, in vitro bioassays do not always detect compounds that disrupt hormone systems through mechanisms other than binding to hormone receptors. As a result, in vivo bioassays, usually performed with fish, may provide more accurate results. A clear dose-related response to various endocrine-disrupting compounds has been established in fish; however, little is known about species differences in sensitivity to exposure. Individual responses to exposure may also vary widely (Routledge et al., 1998). Because many laboratories are unable to perform in vivo bioassays under the necessary conditions (e.g., flow-through tests with rainbow trout), in vivo bioassays are not always practical. Available data suggest that nitrification/denitrification and filtration can reduce the concentrations of hormones and detergent metabolites while reverse osmosis lowers concentrations to levels that are unlikely to cause endocrine disruption (Huang and Sedlak, 2001 and Fujita et al., 1996). The current focus of research on disruption of the estrogen system may be attributable to the relative ease of detecting this form of endocrine disruption. As additional research is performed, other chemicals in wastewater effluent may be found to disrupt hormonal systems through mechanisms yet to be documented. For example, although results from in vitro bioassays suggest that the steroid hormones are most likely responsible for feminization of fish, it is possible that other endocrine disrupters contribute to the effect through mechanisms that cannot be detected by the bioassays. The ecological implications associated with the feminization of fish are unknown. The potential of reclaimed water to cause endocrine disruption in humans is also unknown. It is anticipated that problems associated with endocrine disruption could occur, given prolonged consumption of substantial volumes of polluted water. The compounds in wastewater effluent that are believed to be responsible for feminization of fish may not pose a serious risk for humans because of differences between human and fish physiology. For example, the hormone 17b-estradiol is not used in the oral form in clinical applications because it would be metabolized before it could reach its target. Nevertheless, the evidence of endocrine disruption in wildlife and the absence of data about the effects of low-level exposure to endocrine disrupting compounds in humans has led to new scrutiny regarding endocrine-disrupting chemicals in reclaimed water.


Treatment Requirements

Untreated municipal wastewater may include contributions from domestic and industrial sources, infiltration and inflow from the collection system, and, in the case of combined sewer systems, urban stormwater runoff. The quantity and quality of wastewater derived from each source will vary among communities, depending on the number and type of commercial and industrial establishments in the area and the condition of the sewer system. Levels of wastewater treatment are generally classified as preliminary, primary, secondary, and advanced. Advanced wastewater treatment, sometimes referred to as tertiary treatment, is generally defined as anything beyond secondary treatment. A generalized flow sheet for municipal wastewater treatment is shown in Figure 310. In the last decade, significant advances were made in wastewater treatment equipment, design, and technology. For example, biological nutrient removal (BNR) processes have become more refined. Membranes are capable of producing higher quality effluent at higher flux rates and lower pressures than was possible before. Membrane bioreactors (MBRs) have shown to be effective in producing a high quality effluent, while greatly reducing a treatment plant’s footprint. Microfiltration, used in some locations to replace conventional media filtration, has the advantage of effectively removing all parasite cysts (e.g., Giardia and Cryptosporidium). Advances in UV radiation technology have resulted in a cost competitive disinfection process capable of reducing the concentration of most pathogens to extremely low levels. Wastewater treatment from raw to secondary is well understood and covered in great detail in other publications such as the Manual of Practice (MOP) 8, Design of Municipal Wastewater Treatment Plants, 4th Edition, (WEF, 1998). In this edition of the Guidelines for Water Reuse the discussion about treatment processes will be limited to those with a particular application to water reuse and reclamation. Such processes generally consist of disinfection and treatment beyond secondary treatment, although some limited access reuse programs may use secondary effluent without concern. It should be pointed out that treatment for particular pollutants at the water reclamation facility is not always the best answer. Source controls should also be investigated. In Orange County, California, 1,4-dioxane (listed as a probable human carcinogen based on animal studies) was found in 9 production wells at levels greater than the California action levels. This problem was solved by working with a treatment plant customer who voluntarily ceased discharge


of 1,4-dioxane to the sewer system (Woodside and Wehner, 2002). Disinfection

The most important process for the destruction of microorganisms is disinfection. In the U.S., the most common disinfectant for both water and wastewater is chlorine. Ozone and UV light are other prominent disinfectants used at wastewater treatment plants. Factors that should be considered when evaluating disinfection alternatives include disinfection effectiveness and reliability, capital costs, operating and maintenance costs, practicality (e.g., ease of transport and storage or onsite generation, ease of application and control, flexibility, complexity, and safety), and potential adverse effects. Examples of adverse effects include toxicity to aquatic life or formation of toxic or carcinogenic substances. The predomiFigure 3-10.

nant advantages and disadvantages of disinfection alternatives are well known and have been summarized by the EPA in their Wastewater Technology Fact Sheets on Ultraviolet Disinfection (September 1999), Ozone Disinfection (September 1999), and Chlorine Disinfection (September 1999), Design Manual entitled, “Municipal Wastewater Disinfection” and Water Environment Federation (WEF) Manual of Practice FD-10 (1996). The efficiency of chlorine disinfection depends on the water temperature, pH, degree of mixing, time of contact, presence of interfering substances, concentration and form of chlorinating species, and the nature and concentration of the organisms to be destroyed. In general, bacteria are less resistant to chlorine than viruses, which in turn, are less resistant than parasite ova and cysts.

Generalized Flow Sheet for Wastewater Treatment
Preliminary Primary Effluent for� Subsequent Use
Low-Rate Processes
Disinfection/� Pathogen Removal Chlorine� UV

Secondary Effluent for� Subsequent Use
Stabilization Ponds� Aerated Lagoons� Wetlands� Overland Flow� Soil-Aquifer Treatment (SAT) High-Rate Suspended Growth (SG)� • Activated Sludge� • Membrane � � Bioreactor (MBR)� Attached Growth (AG)� • Trickling Filter (TF)� • Biological Aerated � � Filter (BAF)� • Upflow Anaerobic � � Sludge Blanket � � (UASB)� • Rotating Biological � Contactor (RBC) � Mixed Growth (MG)� • Integrated Fixed-� � Film Activated � � Sludge (IFAS)� • MBR� • Trickling Filter/� � Secondary � � Clarification � � (TF/SC)
Disinfection/� Pathogen Removal Chlorine� UV

Advanced Effluent for� Subsequent Use
Disinfection/� Pathogen Removal Chlorine� UV

Nitrogen Removal Screening� Comminution� Grit removal Sedimentation Selective Ion Exchange� Overland Flow� Biological Nutrient Removal (BNR)

Fats, Oils,� and Grease� Removal

Chemically Enhanced� Pretreatment� (CEPT)

Phosphorus Removal Chemical Precipitation� Biological

Suspended Solids Removal • Chemical Coagulation� � Filtration� • Low-Pressure �� � Membranes–Ultrafiltration � � (UF) and Microfiltration (MF)� • Nanofiltration (NF) and � � Reverse Osmosis (RO) � � Membranes� • Advanced Oxidation �� � Processes

Sludge Processing

Secondary� Sedimentation

Organics & Metals Removal Carbon Adsorption� Chemical Precipitation

Disposal Dissolved Solids Removal

Source: Adapted from Pettygrove and Asano, 1985

Reverse Osmosis� Electrodialysis� Distillation� Ion Exchange� Nanofiltration


The chlorine dosage required to disinfect wastewater to any desired level is greatly influenced by the constituents present in the wastewater. Some of the interfering substances are:

Organic constituents, which consume the disinfectant Particulate matter, which protects microorganisms from the action of the disinfectant Ammonia, which reacts with chlorine to form chloramines, a much less effective disinfectant species than free chlorine



by the cellular nucleic acids. This can prevent replication by eliminating the organism’s ability to cause infection. UV radiation is frequently used for wastewater treatment plants that discharge to surface waters to avoid the need for dechlorination prior to release of the effluent. UV is receiving increasing attention as a means of disinfecting reclaimed water for the following reasons: (1) UV may be less expensive than disinfecting with chlorine, (2) UV is safer to use than chlorine gas, (3) UV does not result in the formation of chlorinated hydrocarbons, and (4) UV is effective against Cryptosporidium and Giardia, while chlorine is not. The effectiveness of UV radiation as a disinfectant (where fecal coliform limits are on the order of 200/100 ml) has been well established, and is used at small- to mediumsized wastewater treatment plants throughout the U.S. Today, UV radiation to achieve high-level disinfection for reuse operations is acceptable in some states. In recognition of the possible harmful effects of chlorine, the Florida Department of Environmental Protection (FDEP) encourages the use of alternative disinfection methods (FDEP, 1996). The WERF published a final report entitled, “Disinfection Comparison of UV Irradiation to Chlorination: Guidance for Achieving Optimal UV Performance.” This report provides a broad-based discussion of the advantages and disadvantages of chlorine and UV, using an empirical model to determine the UV dose required for various levels of coliform inactivation. The report also includes cost information and a comparison of chlorination/dechlorination and UV systems (WERF, 1995). Studies in San Francisco, California, indicated that suspended solids play a major role in UV efficiency. This included the finding that, as the concentration of particles 7 mm and larger increase, the ability to achieve acceptable disinfection with UV decreases. Thus, filtration must be optimized to manage this problem (Jolis et al., 1996). The goal of UV disinfection in reuse applications typically is to inactivate 99.999 percent or more of the target pathogens (Swift et al., 2002). The 2000 National Water Research Institute (NWRI) guidelines provide detailed guidance for the design of UV systems that will achieve high-level disinfection to meet some state standards for public access reuse. The 2000 NWRI guidelines also include a well-defined testing protocol and validation test as a means to provide reasonable assurance that the domestic wastewater treatment facility can meet the high-level disinfection criteria (NWRI and AWWA, 2000). The Bethune Point WWTP in Daytona Beach, Florida, is the largest UV disinfection system in the state of Florida designed for reuse operations. This facility is also the

In practice, the amount of chlorine added is determined empirically, based on desired residual and effluent quality. Chlorine, which in low concentrations is toxic to many aquatic organisms, is easily controlled in reclaimed water by dechlorination, typically with sulfur dioxide. Chlorine is a regulated substance with a threshold quantity of 2,500 pounds (1130 kg). If a chlorine system contains a larger quantity of chlorine than the threshold quantity, a Risk Management Plan (RMP) must be completed. Two main factors of the RMP that prompt many municipalities to switch to alternative disinfection systems are: (1) the RMP is not a one-time requirement, it has to be updated every 5 years; and (2) concern over public reaction to the RMP, which requires that a “kill zone” be geographically defined around the treatment facility. This “kill zone” may include residential areas near the treatment plant. Thus, RMP requirements and decreasing chemical costs for commercial grade sodium hypochlorite have resulted in many municipalities switching from chlorine gas to commercial grade sodium hypochlorite to provide disinfection of their wastewater. Ozone (O3), is a powerful disinfecting agent and chemical oxidant in both inorganic and organic reactions. Due to the instability of ozone, it must be generated onsite from air or oxygen carrier gas. Ozone destroys bacteria and viruses by means of rapid oxidation of the protein mass, and disinfection is achieved in a matter of minutes. Ozone is a highly effective disinfectant for advanced wastewater treatment plant effluent, removing color, and contributing dissolved oxygen. Some disadvantages to using ozone for disinfection are: (1) the use of ozone is relatively expensive and energy intensive, (2) ozone systems are more complex to operate and maintain than chlorine systems, and (3) ozone does not maintain a residual in water. UV is a physical disinfecting agent. Radiation at a wavelength of 254 mm penetrates the cell wall and is absorbed


first public access reuse facility in Florida with UV disinfection to be permitted for unrestricted public access (Elefritz, 2002). Placed into service in December 1999, the Bethune Point WWTP UV disinfection system is a medium pressure/high intensity system designed for a dose of 80mW-s/cm2 (800 J/m2) to achieve the high-level disinfection standard. The City of Henderson, Nevada water reclamation facility conducted collimated beam studies of a low pressure/high intensity UV disinfection system. The studies demonstrated that the disinfection goal of 20 fecal coliforms per 100 ml was achievable with a minimum UV dose of 200 J/m2 (Smith and Brown, 2002). Other disinfectants, such as onsite chlorine generation, gamma radiation, bromine, iodine, and hydrogen peroxide, have been considered for the disinfection of wastewater. These disinfectants are not generally used because of economical, technical, operational, or disinfection efficiency considerations. Advanced Wastewater Treatment

of removing the constituents of concern are shown in Figure 3-11. The principal advanced wastewater treatment processes for water reclamation are:

Filtration – Filtration is a common treatment process used to remove particulate matter prior to disinfection. Filtration involves the passing of wastewater through a bed of granular media or filter cloth, which retain the solids. Typical media include sand, anthracite, and garnet. Removal efficiencies can be improved through the addition of certain polymers and coagulants. UV Treatment of NDMA – UV Treatment, considered an Advanced Oxidation Technology (AOT), is the only proven treatment to effectively reduce NDMA. The adsorption of ultraviolet light, even the UV portion of sunlight, by NDMA causes the molecule to disassociate into harmless fragments (Nagel et al., 2001). A study done at West Basin Municipal Water District in Carson, California proved NDMA concentrations were reduced by both low and medium pressure UV (Nagel et al., 2001). to any wastewater treatment process that biologically converts ammonia nitrogen sequentially to ni-


Advanced wastewater treatment processes are those beyond traditional secondary treatment. These processes are generally used when high quality reclaimed water is needed. Examples include: (1) urban landscaping, (2) food crops eaten raw, (3) contact recreation, and (4) many industrial applications. Individual unit processes capable

„ Nitrification – Nitrification is the term generally given

Figure 3-11.

Particle Size Separation Comparison Chart

Adapted from AWWA, 1990


trite nitrogen and nitrate nitrogen. Nitrification does not remove significant amounts of nitrogen from the effluent; it only converts nitrogen into another chemical form. Nitrification can be achieved in many suspended and attached growth treatment processes when the processes are designed to foster the growth of nitrifying bacteria. In the traditional activated sludge process, this is accomplished by designing the process to operate at a solids retention time (SRT) that is long enough to prevent slow-growing nitrifying bacteria from being wasted out of the system. Nitrification will also occur in trickling filters that operate at low BOD/TKN ratios either in combination with BOD removal, or as a separate advanced treatment process following any type of secondary treatment. A well-designed and -operated nitrification process will produce an effluent containing 1.0 mg/l or less of ammonia nitrogen.
„ Denitrification – Denitrification is any wastewater treat-

of less than 0.1 mg/l, while biological phosphorus removal will usually produce an effluent phosphorus concentration between 1.0 and 2.0 mg/l.
„ Coagulation-Sedimentation – Chemical coagulation

with lime, alum, or ferric chloride followed by sedimentation removes SS, heavy metals, trace substances, phosphorus, and turbidity.
„ Carbon Adsorption – One effective advanced waste-

ment method that completely removes total nitrogen. As with ammonia removal, denitrification is usually best achieved biologically, in which case it must be preceded by nitrification. In biological denitrification, nitrate nitrogen is used by a variety of heterotrophic bacteria as the terminal electron acceptor in the absence of dissolved oxygen. In the process, the nitrate nitrogen is converted to nitrogen gas, which escapes to the atmosphere. The bacteria in these processes also require a carbonaceous food source. Denitrification can be achieved using many alternative treatment processes including variations of many common suspended growth and some attached growth treatment processes, provided that the processes are designed to create the proper microbial environment. Biological denitrification processes can be designed to achieve effluent nitrogen concentrations between 2.0 and 12 mg/l of nitrate nitrogen.
„ Phosphorus Removal – Phosphorus can be removed

water treatment process for removing biodegradable and refractory organic constituents is granular activated carbon (GAC). Carbon adsorption can reduce the levels of synthetic organic chemicals in secondary effluent by 75 to 85 percent. The basic mechanism of removal is by adsorption of the organic compounds onto the carbon. Carbon adsorption proceeded by conventional secondary treatment and filtration can produce an effluent with a BOD of 0.1 to 5.0 mg/ l, a COD of 3 to 25 mg/l, and a TOC of 1 to 6 mg/l. Carbon adsorption treatment will also remove several metal ions, particularly cadmium, hexavalent chromium, silver, and selenium. Activated carbon has been used to remove uncharged species, such as arsenic and antimony, from an acidic stream. Carbon adsorption has also been reported as an effective means of removing endocrine disrupting compounds (Hunter and Long, 2002).

from wastewater through chemical or biological methods, or a combination. The choice of methods will depend on site-specific conditions, including the amount of phosphorus to be removed and the desired effluent phosphorus concentration. Chemical phosphorus removal is achieved by precipitating the phosphorus from solution through the addition of iron, aluminum, or calcium salts. Biological phosphorus removal relies on the culturing of bacteria that will store excess amounts of phosphorus when exposed to anaerobic conditions, followed by aerobic conditions in the treatment process. In both cases, the phosphorus is removed from the treatment process with the waste sludge. Chemical phosphorus removal can attain effluent orthophosphorus concentrations

Membrane Processes – In recent years, the same factors that favor the use of membranes for potable water treatment (increasing demand, decreasing source water quality, and more stringent regulatory standards) are influencing their use in treating wastewaters prior to reuse. Improvements in membrane technologies which separate suspended solids, dissolved compounds, and human pathogens (protozoan cysts, bacteria and viruses) from reclaimed water have inspired greater confidence in the use of reclaimed water for purposes which include both direct and indirect human contact. Membrane filters became commercially available in 1927 from the Sartorius Company in Germany. Until the mid-1940s, these filters were used primarily to remove microorganisms and particles from air and water. The first viable reverse osmosis membrane was developed in 1960 by researchers at the University of California at Los Angeles (UCLA). The first commercial reverse osmosis (RO) treatment plant went into service in 1965 in Coalinga, California. The use of membrane filtration systems was initially limited to specialized applications including industrial separation processes and seawater desalination. By


the 1980s, membrane technology was well established. For many years, membranes were not used for wastewater treatment due to rapid fouling. Prior to 1990, there were a few notable exceptions, including a highly publicized 5-mgd RO system at the Water Factory 21 reclamation plant in Orange County, California. This system went into service in 1975. The plant used cellulose acetate membranes with lime clarification and multi-media filtration for pretreatment prior to the RO system. Another notable exception was a 3.3-mgd (12 x 103-m3/d) Petromin plant in Riyadh, Saudia Arabia. The large-scale use of membranes for wastewater reclamation did not become feasible until the1980s, when the Australian firm, Memtec, developed a hollow fiber microfiltration membrane system with an air backwash that could provide sustainable operation for wastewater. The Orange County Water District (California) began pilot testing in 1992 to investigate this new microfiltration system as pretreatment for reverse osmosis. The use of this new microfiltration system, followed by thin film composite RO membranes, proved to be a tremendous improvement over the then-conventional system of lime clarification, sand filtration, and cellulose acetate membranes. Between 1994 and 2000, over half a dozen new dual membrane water reclamation systems were constructed in California and Arizona. Pressure-driven membrane treatment systems are broadly categorized by the size particles rejected by the membrane, or by the molecular weight cut off (MWCO). These classifications include:

(sand) filters following biological treatment. UF membranes have smaller pore sizes than MF membranes and will provide complete removal of bacteria and protozoan cysts, and 4 to 6 log removal for viruses. Otherwise, UF membranes perform the same basic functions in wastewater applications as MF membranes. NF and RO, while retaining smaller particles including molecules and ions, require higher driving pressures, higher levels of pretreatment (prefiltration), and typically operate at lower recovery rates. For wastewater treatment, the main emphasis has been on MF, UF, and RO membranes. MF and UF have the ability to remove biological contaminants (e.g., bacteria and viruses), and to reduce fouling on downstream reverse osmosis membranes. NF or RO systems are needed where the removal of colloidal and/or dissolved materials is required. Membrane Bioreactors (MBRs) MBRs typically consist of UF or MF membranes. These membranes are used to replace conventional gravity clarifiers, and return activated sludge systems in conventional activated sludge biological treatment systems. The membranes can be immersed directly into the aeration tanks, or the mixed liquor can be pumped to external pressure-driven membrane units. MBRs exhibit a number of unique advantages:

Sludge settling characteristics no longer affect final effluent quality. Biological processes can be operated at much higher suspended solids concentrations and thereby provide greater treatment capacity per unit volume. MF and UF membranes provide nearly complete removal of protozoan cysts, suspended solids, and bacteria, as well as partial removal of viruses. In addition to removing suspended solids, UF membranes can retain large organic molecules, improving the biodegradation of otherwise resistant compounds such as grease or emulsified oils. Longer sludge ages (as long as 30 to 45 days) are possible, improving the biodegradation of resistant compounds and improving nitrification performance under adverse conditions (such as low temperature). proving process control.

Microfiltration (MF) Ultrafiltration (UF) Nanofiltration (NF) Reverse Osmosis (RO)

0.1 µ m 0.01 µ m 0.001 µm 0.0001 µm

or 500, 000 MWCO or 20,000 MWCO or 200 MWCO or < 100 MWCO

Figure 3-11 shows a particle size separation comparison chart for conventional filtration, microfiltration, ultrafiltration, and reverse osmosis. Tables 3-13a and 3-13b contain microfiltration and reverse osmosis removal data (Metcalf and Eddy, 2002). MF systems are used to remove relatively large suspended particles including particulates, large colloids, and oil. This includes providing about 3 to 6 log (99.9 percent to 99.9999 percent) removal of bacteria. In wastewater treatment, MF systems can be used to replace secondary clarifiers and more conventional


„ Wasting occurs directly from the aeration basin, im-

„ Submerged MBR systems are well suited to upgrade

existing systems with minimum new construction required and low impact to ongoing operations.


Table 3-13a.

Microfiltration Removal Performance Data
MF Influent (m g/l) 10-31 11-32 24-150 8-46 498-622 21-42 <1-5 6-8 90-120 93-115 2-50 NTU MF Effluent (m g/l) 9-16 <2-9.9 16-53 <0.5 498-622 20-35 <1-5 6-8 90-120 93-115 0.03-0.08 NTU Average Reduction Reported in Reduction (%) Literature (%) 57 86 76 97 0 7 0 0 0 0 >99 45-65 75-90 70-85 95-98 0-2 5-15 0-2 0-2 0-1 0-1 ---

Constituent TOC BOD COD TSS TDS NH3-N NO 3-N PO 4 SO 4 Cl



Data collected from the Dublin San Ramon Sanitary District for the period from April 2000 through December, 2000. Typical flux rate during test period was 1600 l/m2·d.

Adapted from: Metcalf and Eddy, 2002 Table 3-13b. Reverse Osmosis Performance Data
Constituent TOC BOD COD TSS TDS NH 3-N NO 3-N PO 4 SO 4 Cl

RO Influent (m g/l) 9-16 <2-9.9 16-53 <0.5 498-622 20-35 <1-5 8-Jun 90-120 93-115 0.03-0.08 NTU

RO Effluent (m g/l) <0.5 <2 <2 ~0 9-19 1-3 0.08-3.2 0.1-1 <0.5-0.7 0.9-5.0 0.03 NTU

Average Reduction Reporte d in Reduction (%) Lite rature (%) >94 >40 >91 >99 --96 96 ~99 99 97 50 85-95 30-60 85-95 95-100 90-98 90-98 65-85 95-99 95-99 90-98 40-80



Data collected from the Dublin San Ramon Sanitary District for the period from April 1999 through December, 1999. Typical flux rate during test period was 348 l/m2·d.

Adapted from: Metcalf and Eddy, 2002 Submerged membrane assemblies, either MF or UF, are typically composed of bundles of hollow fiber or flat sheets of microporous membranes. Filtrate is drawn through the membrane assemblies by means of a vacuum applied to the product side of the membrane. Turbulence on the exterior (feed side) is maintained by diffused aeration to reduce fouling. Low-pressure membrane filtration (MF or UF) can be used following secondary clarification to provide a


higher degree of solids removal. Operating in a conventional (pressurized) flow pattern, clarified effluent is further treated to remove particulate material (MF) or colloidal material (UF). Typical operating pressures range from 20 to 100 psi (100 to 700 KPa), and reject flows range from 2 to 50 percent. MF and UF membranes can be used to pre-treat flow prior to NF or RO treatment. Higher-pressure NF and RO systems are used to remove dissolved organic and inorganic compounds. The smaller pore size (lower MWCO) results in higher quality product water, which may meet primary and secondary drinking water standards. The higher rates of rejection also result in increasing problems for disposing of the concentrate streams.
„ Other Processes – Other advanced wastewater treat-

„ Operator certification to ensure that qualified person-

nel operate the water reclamation and reclaimed water distribution systems
„ Instrumentation and control systems for on-line moni-

toring of treatment process performance and alarms for process malfunctions

A comprehensive quality assurance program to ensure accurate sampling and laboratory analysis protocol ter of unacceptable quality for re-treatment or alternative disposal

„ Adequate emergency storage to retain reclaimed wa-

„ Supplemental storage and/or water supply to ensure

that the supply can match user demands

ment processes of constituent removal include ammonia stripping, breakpoint chlorination for ammonia removal, and selective ion exchange for nitrogen removal.


Reliability in Treatment

A strict industrial pretreatment program and strong enforcement of sewer use ordinances to prevent illicit dumping into the collection system of hazardous materials or other materials that may interfere with the intended use of the reclaimed water responsibilities and duties of the operations staff to ensure the reliable production and delivery of reclaimed water

A high standard of reliability, similar to water treatment plants, is required at wastewater reclamation plants. Because there is potential for harm (i.e., in the event that improperly treated reclaimed water is delivered to the use area), water reuse requires strict conformance to all applicable water quality parameters. The need for reclamation facilities to reliably and consistently produce and distribute reclaimed water of adequate quality and quantity is essential and dictates that careful attention be given to reliability features during the design, construction, and operation of the facilities. A number of fallible elements combine to make up an operating water reclamation system. These include the power supply, individual treatment units, mechanical equipment, the maintenance program, and the operating personnel. An array of design features and non-design provisions can be employed to improve the reliability of the separate elements and the system as a whole. Backup systems are important in maintaining reliability in the event of failure of vital components. Particularly critical units include the disinfection system, power supply, and various treatment unit processes. For reclaimed water production, EPA Class I reliability is recommended as a minimum criteria. Class I reliability requires redundant facilities to prevent treatment upsets during power and equipment failures, flooding, peak loads, and maintenance shutdowns. Reliability for water reuse should also consider:

„ A comprehensive operating protocol that defines the

Many states have incorporated procedures and practices into their reuse rules and guidelines to enhance the reliability of reclaimed water systems. Florida requires the producer of reclaimed water to develop a detailed operating protocol for all public access systems. This protocol must identify critical monitoring and control equipment, set points for chlorine and turbidity, actions to be taken in the event of a failure to achieve these limits, and procedures to clear the substandard water and return to normal operations (FAC 62-610). Washington is in the process of developing Water Reclamation Facilities Reliability Assessment Guidance, which includes an alarm and reliability checklist. EPA Guidelines for Reliability

More than 30 years ago, before the Federal Water Quality Administration evolved into the EPA, it recognized the importance of treatment reliability, issuing guidelines entitled, “Federal Guidelines: Design, Operation and Maintenance of Waste Water Treatment Facilities” (Federal Water Quality Administration, 1970). These guidelines provided an identification and description of various reliability provisions and included the following concepts or principles regarding treatment plant reliability:



All water pollution control facilities should be planned and designed to provide for maximum reliability at all times. Each facility should be capable of operating satisfactorily during power failures, flooding, peak loads, equipment failure, and maintenance shutdowns. Such reliability can be obtained through the use of various design techniques that will result in a facility that is virtually “fail-safe” (Federal Water Quality Administration, 1970).

Piping and pumping flexibility Dual chlorination systems Automatic residual control Automatic alarms Other Factors Engineering report Qualified personnel Effective monitoring program Effective maintenance and process control program In 1974, EPA subsequently published a document entitled, “Design Requirements for Mechanical, Electric, and Fluid Systems and Component Reliability” (U.S. EPA, 1974). While the purpose of that publication was to provide reliability design criteria for wastewater treatment facilities seeking federal financial assistance under PL 92-500, the criteria are useful for the design and operation of all wastewater treatment plants. These requirements established minimum standards of reliability for wastewater treatment facilities. Other important reliability design features include on-line monitoring (e.g., turbidimeters and chlorine residual analyzers, and chemical feed facilities. Table 3-14 presents a summary of the equipment requirements under the EPA guidelines for Class I reliability treatment facilities. As shown in Table 3-14, the integrity of the treatment system is enhanced by providing redundant, or oversized unit processes. This reliability level was originally specified for treatment plants discharging into water bodies that could be permanently or unacceptably damaged by improperly treated effluent. Locations where Class I facilities might be necessary are indicated as facilities discharging near drinking water reservoirs, into shellfish waters, or in proximity to areas used for water contact sports (U.S. EPA, 1974). While over 30 years old, the definition of Class I Reliability given in Table 3-14 is still referenced in the regulations of many states as the minimum level of reliability required for water reclamation projects.



The following points highlight more specific subjects for consideration in preparing final construction plans and specifications to help accomplish the above principles:
„ Duplicate dual feed sources of electric power „ Standby onsite power for essential plant elements „ Multiple process units and equipment „ Holding tanks or basins to provide for emergency stor-

age of overflow and adequate pump-back facilities

Flexibility of piping and pumping facilities to permit rerouting of flows under emergency conditions Provision for emergency storage or disposal of sludge (Federal Water Quality Administration, 1970)


The non-design reliability features in the federal guidelines include provisions for qualified personnel, an effective monitoring program, and an effective maintenance and process control program. In addition to plans and specifications, the guidelines specify submission of a preliminary project planning and engineering report, which will clearly indicate compliance with the guideline principles. In summary, the federal guidelines identify the following 8 design principles and 4 other significant factors that appear to be appropriate to consider for reuse operations: Design Factors Duplicate power sources Standby power Multiple units and equipment Emergency storage


Table 3-14.

Summary of Class I Reliability Requirements

Unit Mechanically-Cleaned Bar Screen Pumps

Clas s I Re quire m e nt A back-up bar screen shall be provided (may be manually cleaned). A back-up pump shall be provided for each set of pumps which perform the same function. Design flow will be maintained with any 1 pump out of service. If comminution is provided, an overflow bypass with bar screen shall be provided. There shall be sufficient capacity such that a design flow capacity of 50 % of the total capacity will be maintained with the largest unit out of service. There shall be a sufficient number of units of a size such that a design capacity of at least 75 % of the total flow will be maintained with 1 unit out of service. At least 2 basins of equal volume will be provided. At least 2 mechanical aerators shall be provided. Design oxygen transfer will be maintained with 1 unit out of service. At least 2 basins or a back-up means of mixing chemicals separate from the basins shall be provided. There shall be a sufficient number of units of a size such that 75% of the design capacity will be maintained with the largest unit out of service. At least 2 basins shall be provided. There shall be sufficient number of units of a size such that the capacity of 50% of the total design flow may be treated with the largest unit out of service.

Comminution Facilities Primary Sedimentation Basins


Aeration Basins Mechanical Aerator Chemical Flash Mixer Final Sedimentation Basins

Flocculation Basins Disinfectant Contact Basins

Source: Adapted from U.S. Environmental Protection Agency, 1974

Additional Requirements for Reuse Applications


Piping and Pumping Flexibility

Different degrees of hazard are posed by process failures. From a public health standpoint, it is logical that a greater assurance of reliability should be required for a system producing reclaimed water for uses where direct or indirect human contact with the water is likely, than for water produced for uses where the possibility of contact is remote. Similarly, where specific constituents in reclaimed water may affect the acceptability of the water for any use (e.g., industrial process water), reliability directed at those constituents is important. Standby units or multiple units should be encouraged for the major treatment elements at all reclamation facilities. For small installations, the cost may be prohibitive and provision for emergency storage or disposal is a suitable alternative.

Process piping, equipment arrangements, and unit structures should provide for efficiency, ease of operation and maintenance, and maximum flexibility of operation. Flexibility plans should permit the necessary degree of treatment to be obtained under varying conditions. All aspects of plant design should allow for routine maintenance of treatment units without deterioration of the plant effluent. No pipes or pumps should be installed that would circumvent critical treatment processes and possibly allow inadequately treated effluent to enter the reclaimed water distribution system. The facility should be capable of operating during power failures, peak loads, equipment failures, treatment plant upsets, and maintenance shutdowns. In some cases, it may be necessary to divert the wastewater to emergency storage facilities or


discharge the wastewater to approved, non-reuse areas. During power failures or in the case of an equipment failure, standby portable diesel-driven pumps can also be used. b. Emergency Storage or Disposal

Where emergency storage is to be used as a reliability feature, storage capacity is an important consideration. This capacity should be based on estimates of how long it will take to return the facilities to normal operations and the penalties (regulatory or otherwise) associated with loss of treatment and discontinuation of reclaimed water service. c. Alarms

The term “emergency storage or disposal” means to provide for the containment or alternative treatment and disposal of reclaimed water whenever the quality is not suitable for use. It refers to something other than normal operational or seasonal storage (e.g., storage that may be used to hold reclaimed water during wet weather times until it is needed for use). Provisions for emergency storage or disposal may be considered to be a basic reliability provision for some reclamation facilities. Where such provisions exist, they may substitute for multiple or standby units and other specific features. Provisions for emergency storage or disposal may include:
„ Holding ponds or tanks „ Approved alternative disposal locations such as per-

colation areas, evaporation-percolation ponds, or spray disposal areas
„ Deep injection wells „

Alarm systems should be installed at all water reclamation plants, particularly at plants that do not receive fulltime attention from trained operators. Minimum instrumentation should consist of alarms at critical treatment units to alert an operator of a malfunction. This concept requires that the plant either be constantly attended, or that an operator be on call whenever the reclamation plant is in operation. In the latter case, a remote sounding device would be needed. If conditions are such that rapid attention to failures cannot be assured, automatically actuated emergency control mechanisms should be installed and maintained. Supervisory control and data acquisition (SCADA) systems may be employed to accomplish this objective, so long as information is made available to locations that are staffed when operators are not on site at the remote reclaimed water facilities. If a critical process were to fail, the condition may go unnoticed for an extended time period, and unsatisfactory reclaimed water would be produced for use. An alarm system will effectively warn of an interruption in treatment. Requirements for warning systems may specify the measurement to be used as the control in determining a unit failure (e.g., dissolved oxygen) in an aeration chamber or the requirements could be more general in nature, merely specifying the units or processes that should be included in a warning system. The latter approach appears more desirable because it allows for more flexibility in the design. Alarms could be actuated in various ways, such as failure of power, high water level, failure of pumps or blowers, loss of dissolved oxygen, loss of coagulant feed, high head loss on filters, high effluent turbidity, or loss of disinfection. In addition to the alarm system, it is critical to have a means available to take corrective action for each situation, which has caused the alarm to be activated. As noted above, provisions must be available to otherwise treat, store, or dispose of the wastewater until the corrections have been made. Alternative or supplemental features for different situations might include an automatic switchover mechanism to emergency power and a self-starting generator, or an automatic diversion mechanism which discharges wastewater from the various treatment units to emergency storage or disposal.

Pond systems having an approved discharge to receiving waters or discharge to a reclaimed water use area for which lower quality water is acceptable Provisions to return the wastewater to a sewer for subsequent treatment and disposal at the reclamation or other facility Any other facility reserved for the purpose of emergency storage or disposal of untreated or partiallytreated wastewater



Automatically-actuated emergency or disposal provisions should include all of the necessary sensors, instruments, valves, and other devices to enable fully automatic diversion of the wastewater in the event of failure of a treatment process, and a manual reset to prevent automatic restart until the failure is corrected. For either manual or automatic diversion, all of the equipment other than the pump-back equipment should either be independent of the normal power source or provided with a standby power source. Irvine Ranch Water District in California automatically diverts its effluent to a pond when it exceeds a turbidity of 2 NTU. The water is then recirculated into the reclamation plant influent.



Instrumentation and Control

„ „

Ability to provide service and Reliability

Major considerations in developing an instrumentation/ control system for a reclamation facility include:
„ Ability to analyze appropriate parameters „

Source: WPCF, 1989 Ability to maintain, calibrate, and verify accuracy of on-line instruments Monitoring and control of treatment process performance Monitoring and control of reclaimed water distribution Methods of providing reliability Operator interface and system maintenance Each water reclamation plant is unique, with its own requirements for an integrated monitoring and control instrumentation system. The process of selecting monitoring instrumentation should address aspects such as frequency of reporting, parameters to be measured, sample point locations, sensing techniques, future requirements, availability of trained staff, frequency of maintenance, availability of spare parts, and instrument reliability (WPCF, 1989). Such systems should be designed to detect operational problems during both routine and emergency operations. If an operating problem arises, activation of a signal or alarm permits personnel to correct the problem before an undesirable situation is created. System control methods should provide for varying degrees of manual and automatic operation. Functions of control include the maintenance of operating parameters within preset limits, sequencing of physical operations in response to operational commands and modes, and automatic adjustment of parameters to compensate for variations in quality or operating efficiency. System controls may be manual, automated, or a combination of manual and automated systems. For manual control, operations staff members are required to physically carry out all work tasks, such as closing and opening valves and starting and stopping pumps. For automated control, no operator input is required except for the initial input of operating parameters into the control system. In an automated control system, the system automatically performs operations such as the closing and opening of valves and the starting and stopping of pumps. These automated operations can be accomplished in a predefined sequence and timeframe and can also be initiated by a measured parameter. Automatic controls can vary from simple float switches that start and stop pumps to highly sophisticated computer systems that gather data from numerous sources, compare the data to predefined parameters, and initiate actions in order to maintain system performance within required criteria. For example, in the backwashing of a filter, instrumentation that monitors head loss across a filter signals the automated control system that a predefined head loss value has been exceeded. The control system, in turn, initiates the backwashing sequence through the opening of valves and starting of pumps. A simple, but effective, means of maintaining control in the event of a power failure might include a judicious se-



„ „

The potential uses of the reclaimed water determine the degree of instrument sophistication and operator attention required in a water reuse system. For example, health risks may be insignificant for reclaimed water used for non-food crop irrigation. On the other hand, if wastewater is being treated for indirect potable reuse via groundwater recharge, risks are potentially high. Consequently, the instruments must be highly sensitive so that even minor discrepancies in water quality are detected rapidly. Selection of monitoring instrumentation is governed by the following factors:
„ „ „ „

Sensitivity Accuracy Effects of interferences Frequency of analysis and detection

„ Laboratory or field application „ „

Analysis time Sampling limitations

„ Laboratory requirements „ „

Acceptability of methods Physical location


lection of how control valves respond to loss of power. For example, in a reuse system with a pair of control valves routing water either to customers or to a reject location, it is reasonable to expect that the valve to the customers should fail to the closed position, while the valve to reject would fail to the open position. Operator Training and Competence

„ Standard Methods for the Examination of Water and

Wastewater (American Public Health Association, 1989)
„ Handbook for Analytical Quality Control in Water and

Wastewater Laboratories (U.S. EPA, 1979a)
„ Methods for Chemical Analysis of Water and Wastes

(U.S. EPA, 1983)
„ Methods for Organic Chemical Analysis of Municipal

Regardless of the automation built into a plant, mechanical equipment is subject to breakdown, and qualified, well-trained operators are essential to ensure that the reclaimed water produced will be acceptable for its intended use. The facilities operation should be based on detailed process control with recording and monitoring facilities, a strict preventive maintenance schedule, and standard operating procedure contingency plans all structured to provide reliable product water quality. The plant operator is considered to be the most critical reliability factor in the wastewater treatment system. All available mechanical reliability devices and the best possible plant design are to no avail if the operator is not capable and conscientious. Three operations personnel considerations influence reliability of treatment: operator attendance, operator competence, and operator training. The knowledge, skills, and abilities that an operator must possess varies, depending on the complexity of the plant. Most regulatory agencies require operator certification as a reasonable means to expect competent operation. Frequent training via continuing education courses or other means enhances operator competence. Actions of the system operator have the potential to adversely affect water quality and public perception of the reclaimed water system. Therefore, a knowledgeable, attentive operator is critical to avoid potential threats to water quality. Consideration should be given to provide special training and certification for reclaimed water operations staff. Quality Assurance in Monitoring

and Industrial Wastewater (U.S. EPA, 1996)
„ Handbook for Sampling and Sample Preservation of

Water and Wastewater (U.S. EPA, 1982) Typically, the QA plan associated with sampling and analysis is a defined protocol that sets forth data quality objectives and the means to develop quality control data. This serves to quantify precision, bias, and other reliability factors in a monitoring program. Strict adherence to written procedures ensures that the results are comparable, and that the level of uncertainty is verifiable. Quality assurance/quality control (QA/QC) plans and procedures are well documented in referenced texts. QA/QC measures should be dictated by the severity of the consequences of acting on the “wrong answer” or on an “uncertain” answer. QA/QC procedures are often dictated by regulatory agencies, and do constitute necessary operating overhead. For reuse projects, this overhead may be greater than for wastewater treatment and disposal. Sampling parameters required for reclamation extend beyond those common to wastewater treatment. For example, turbidity measurements are sometimes required for reclamation, but not for wastewater treatment and disposal. Monitoring for chlorides may be necessary for reuse in coastal communities. Adequate record keeping of reclaimed water system operations is essential to the overall monitoring program. Many facilities find it reasonable and compatible with their usual practice and requirements to include routine reporting of plant operations and immediate notification of emergency conditions.

Quality assurance (QA) in monitoring of a reclamation program includes: (1) selecting the appropriate parameters to monitor, and (2) handling the necessary sampling and analysis in an acceptable manner. Sampling techniques, frequency, and location are critical elements of monitoring and quality assurance. Standard procedures for sample analysis may be found in the following references:


Seasonal Storage Requirements

Managing and allocating reclaimed water supplies may be significantly different from the management of traditional sources of water. Traditionally, a water utility drawing from groundwater or surface impoundments uses the resource as a source and as a storage facility. If the


entire yield of the source is not required, the water is simply left for use at a later date. Yet in the case of reuse, reclaimed water is continuously generated, and what cannot be used immediately must be stored or disposed of in some manner. Depending on the volume and pattern of projected reuse demands, seasonal surface storage requirements may become a significant design consideration and have a substantial impact on the capital cost of the system. Seasonal storage systems will also impact operational expenses. This is particularly true if the quality of the water is degraded in storage by algae growth and requires re-treatment to maintain the desired or required water quality. Pilot studies in California investigated the use of clarifiers with coagulation and continuous backwash filtration versus the use of dissolved air flotation with clarification and filtration. The estimated present worth costs of these 2 strategies for treating reclaimed water returned from storage ponds were calculated at $1.92/gal ($0.51/l) and $2.17/gal ($0.57/l), respectively (Fraser and Pan, 1998). The need for seasonal storage in reclaimed water programs generally results from 1 of 2 requirements. First, storage may be required during periods of low demand for subsequent use during peak demand periods. Second, storage may be required to reduce or eliminate the discharge of excess reclaimed water into surface water or groundwater. These 2 needs for storage are not mutually exclusive, but different parameters are considered in developing an appropriate design for each one. In fact, projects where both water conservation and effluent disposal are important are more likely to be implemented than those with a single driver. Drivers for the creation of an urban reuse system in Tampa, Florida included water conservation as well as the fact that any reclaimed water diverted to beneficial reuse helped the City to meet its obligations to reduce nitrogen loadings to area surface waters (Grosh et al., 2002). At the outset, it must be recognized that the use of traditional storage methods with finite capacities (e.g., tanks, ponds, and reservoirs) must be very large in comparison to the design flows in order to provide 100 percent equalization of seasonal supplies and demands. With an average flow of 18 mgd (68 x 103 m3/d) and a storage volume of 1,600 million gallons (6 x 106 m3), the City of Santa Rosa, California, still required a seasonal discharge to surface water to operate successfully (Cort et al., 1998). After attempting to operate a 3.0 mgd (11 x 103 m3/d) agricultural reuse system with 100 mg (0.4 x 106 m3) of storage, Brevard County, Florida, decided to add manmade wetlands with a permitted surface water discharge as part of its wet weather management system (Martens et al., 1998).

ASR of reclaimed water involves the injection of reclaimed water into a subsurface formation for storage, and recovery for beneficial use at a later time. ASR can be an effective and environmentally-sound approach by providing storage for reclaimed water used to irrigate areas accessible to the public, such as residential lawns and edible crops. These systems can minimize the seasonal fluctuations inherent to all reclaimed water systems by allowing storage of reclaimed water during the wet season when demand is low, and recovery of the stored water during dry periods when demand is high. Because the potential storage volume of an ASR system is essentially unlimited, it is expected that these systems will offer a solution to the shortcomings of the traditional storage techniques discussed above. The use of ASR was also considered as part of the Monterey County, California reuse program in order to overcome seasonal storage issues associated with an irrigation-based project (Jaques and Williams, 1996). Where water reuse is being implemented to reduce or eliminate wastewater discharges to surface waters, state or local regulations usually require that adequate storage be provided to retain excess wastewater under a specific return period of low demand. In some cold climate states, storage volumes may be specified according to projected non-application days due to freezing temperatures. Failure to retain reclaimed water under the prescribed weather conditions may constitute a violation of an NPDES permit and result in penalties. A method for preparing storage calculations under low demand conditions is provided in the EPA Process Design Manual: Land Treatment of Municipal Wastewater (U.S. EPA, 1981 and 1984). In many cases, state regulations will also include a discussion about the methods to be used for calculating the storage that is required to retain water under a given rainfall or low demand return interval. In almost all cases, these methods will be aimed at demonstrating sites with hydrogeologic storage capacity to receive wastewater effluent for the purposes of disposal. In this regard, significant attention is paid to subsurface conditions as they apply to the percolation of effluent into the groundwater with specific concerns as to how the groundwater mound will respond to effluent loading. The remainder of this section discusses the design considerations for seasonal storage systems. For the purpose of discussion, the projected irrigation demands of turf grass in a hot, humid location (Florida) and a hot, arid location (California) are used to illustrate storage calculations. Irrigation demands were selected for illustration because irrigation is a common use of reclaimed water, and irrigation demands exhibit the largest seasonal fluc-


tuations, which can affect system reliability. However, the general methodologies described in this section can also be applied to other uses of reclaimed water and other locations as long as the appropriate parameters are defined.


Identifying the Operating Parameters

In many cases, a water reuse system will provide reclaimed water to a diverse customer base. Urban reuse customers typically include golf courses and parks and may also include commercial and industrial customers. Such is the case in both the City of St. Petersburg, Florida, and Irvine Ranch Water District, California, reuse programs. These programs provide water for cooling, washdown, and toilet flushing as well as for irrigation. Each water use has a distinctive seasonal demand pattern and, thereby, impacts the need for storage. Reuse systems have significant differences with traditional land application systems starting with the fundamental objectives of each. Land application systems seek to maximize hydraulic loadings while reuse systems provide nonpotable waters for uses where a higher quality of water is not required. Historical water use patterns should be used where available. Methodologies developed for land application systems are generally poorly suited to define expected demands of an irrigation-based reuse system and should be replaced with methodologies expressly developed to estimate irrigation needs. This point was illustrated well by calculations of storage required to prevent a discharge based on: (1) actual golf course irrigation use over a 5-year period and (2) use of traditional land application water

balance methods using site-specific hydrogeological information and temperature and rainfall corresponding to the 5-year record of actual use. Use of historical records estimated a required storage volume of 89 days of flow, while traditional land application methods estimated a required storage volume of 196 days (Ammerman et al., 1997). It should also be noted that, like potable water, the use of reclaimed water is subject to the customer’s perceived need for water. The primary factors controlling the need for supplemental irrigation are evapotranspiration and rainfall. Evapotranspiration is strongly influenced by temperature and will be lowest in the winter months and highest in midsummer. Water use for irrigation will also be strongly affected by the end user and their attention to the need for supplemental water. Where uses other than irrigation are being investigated, other factors will be the driving force for demand. For example, demand for reclaimed water for industrial reuse will depend on the needs of the specific industrial facility. These demands could be estimated based on past water use records, if data are available, or a review of the water use practices of a given industry. When considering the demand for water in a manmade wetland, the system must receive water at the necessary time and rate to ensure that the appropriate hydroperiod is simulated. If multiple uses of reclaimed water are planned from a single source, the factors affecting the demand of each should be identified and integrated into a composite system demand. Figure 3-12 presents the average monthly potential evaporation and average monthly rainfall in southwest Florida and Davis, California (Pettygrove and Asano,

Figure 3-12.

Average Monthly Rainfall and Pan Evaporation


1985). The average annual rainfall is approximately 52 inches (132 cm) per year, with an average annual potential evaporation of 71 inches (180 cm) per year in Florida. The average annual rainfall in Davis is approximately 17 inches (43 cm) per year with a total annual average potential evaporation rate of approximately 52 inches (132 cm) per year. In both locations, the shape of the potential evaporation curve is similar over the course of the year; however, the distribution of rainfall at the sites differs significantly. In California, rainfall is restricted to the late fall, winter, and early spring, with little rainfall expected in the summer months when evaporation rates are the greatest. The converse is true for the Florida location, where the major portion of the total annual rainfall occurs between June and September.

months, reflecting the region’s seasonal influx of tourists. The seasonal irrigation demand for reclaimed water in Florida was calculated using the Thornthwaite equation. (Withers and Vipond, 1980). It is interesting to note that even in months where rainfall is almost equal to the potential evapotranspiration, a significant amount of supplemental irrigation may still be required. This occurs as a result of high intensity, short duration, rainfalls in Florida coupled with the relatively poor water-holding capacity of the surficial soils. The average monthly irrigation demand for California, shown in Figure 3-12, is based on data developed by Pruitt and Snyder (Pettygrove and Asano, 1985). Because significant rainfall is absent throughout most of the growing season, the seasonal pattern of supplemental irrigation for the California site is notably different from that of Florida. For the California example, it has been assumed that there is very little seasonal fluctuation in the potential supply of reclaimed water. If the expected annual average demands of a reclaimed water system are approximately equal to the average annual available supply, storage is required to hold water for peak demand months. Using monthly supply and demand factors, the required storage can be obtained from the cumulative supply and demand. The results of this analysis suggest that, to make beneficial use of all available water under average conditions, the Florida reuse program will require approximately 90 days of storage, while California will need approximately 150 days. These calculations are based on the estimated consumptive demand of the turf grass. In actual practice, the estimate would be refined, based on site-specific conditions. Such conditions may include the need to leach


Storage to Meet Irrigation Demands

Once seasonal evapotranspiration and rainfall have been identified, reclaimed water irrigation demands throughout the seasons can be estimated. The expected fluctuations in the monthly need for irrigation of grass in Florida and California are presented in Figure 3-13. The figure also illustrates the seasonal variation in wastewater flows and the potential supply of irrigation water for both locations. In both locations, the potential monthly supply and demand are expressed as a fraction of the average monthly supply and demand. To define the expected fluctuations in Florida’s reclaimed water supply, historic flow data are averaged for each month. The reclaimed water supply for the Florida example indicates elevated flows in the late winter and early spring with less than average flows in the summer

Figure 3-13. Average Pasture Irrigation Demand and Potential Supply


salts from the root zone or to intentionally over-apply water as a means of disposal. The vegetative cover receiving irrigation will also impact the condition under which supplemental water will be required. Drought conditions will result in an increased need for irrigation. The requirements of a system to accommodate annual irrigation demands under drought conditions should also be examined.


Operating without Seasonal Storage

Given the challenges of using storage to equalize seasonal supplies and demands, it is not surprising that many utilities choose to commit only a portion of the available reclaimed water flow to beneficial reuse. A partial commitment of reclaimed water may also have applications in the following situations:

The cost of providing storage for the entire flow is prohibitive Sufficient demand for the total flow is not available entire flow is prohibitive


present more challenges for both internal and external corrosion than typically experienced in the potable water system. Generally, reclaimed water is more mineralized with a higher conductance and chloride content and lower pH, enhancing the potential for corrosion on the interior of the pipe. Because reclaimed water lines are often the last pipe installed, there is an increased opportunity for stray current electrolysis or coating damage (Ryder, 1996). Design requirements will also be affected by the policies governing the reclamation system (e.g., what level of shortfall, if any, can be tolerated?). Where a dual distribution system is created, the design will be similar to that of a potable system in terms of pressure and volume requirements. However, if the reclaimed water distribution system does not provide for an essential service such as fire protection or sanitary uses, the reliability of the reclamation system need not be as stringent. This, in turn, reduces the need for backup systems, thereby reducing the cost of the system. In addition, an urban reuse program designed primarily for irrigation will experience diurnal and seasonal flows and peak demands that have different design parameters than the fire protection requirements generally used in the design of potable water systems. The target customer for many reuse programs may be an entity that is not traditionally part of municipal water/ wastewater systems. Such is the case with agricultural and large green space areas, such as golf courses, that often rely on wells to provide for nonpotable water uses. Even when these sites are not directly connected to municipal water supplies, reclaimed water service to these customers may be desirable for the following reasons:

„ The cost of developing transmission facilities for the


Total abandonment of existing disposal facilities is not cost-effective

Systems designed to use only a portion of the reclaimed water supply are plentiful. It should be noted that a partial commitment of reclaimed water may be able to achieve significant benefits in terms of environmental impacts. Specifically, many surface water discharge permits are based on the 7-day, 10-year (7Q10) low flow expected in the receiving water body. Such events invariably coincide with extended periods of low rainfall, which, in turn, tend to increase the amount of water diverted away from disposal and into the reuse system.

The potential user currently draws water from the same source as that used for potable water, creating an indirect demand on the potable system. The potential user has a significant demand for nonpotable water and reuse may provide a cost-effective means to reduce or eliminate reliance on existing effluent disposal methods. The potential user is seeking reclaimed water service to enhance the quality or quantity (or both) of the water available. A municipal supplier is seeking an exchange of nonpotable reclaimed water for raw water sources currently controlled by the prospective customer.



Supplemental Water Reuse System Facilities
Conveyance and Distribution Facilities

The distribution network includes pipelines, pump stations, and storage facilities. No single factor is likely to influence the cost of water reclamation more than the conveyance or distribution of reclaimed water from its source to its point of use. The design requirements of reclaimed water conveyance systems vary according to the needs of the users. Water quality is, of course, a consideration as well. Reclaimed water systems may


The conveyance and distribution needs of these sites may vary widely and be unfamiliar to a municipality. For example, a golf course may require flows of 500 gpm (38


l/s) at pressures of 120 psi (830 kPa). However, if the golf course has the ability to store and repump irrigation water, as is often the case, reclaimed water can be delivered at atmospheric pressure to a pond at approximately one-third the instantaneous demand. Where frostsensitive crops are served, an agricultural customer may wish to provide freeze protection through the irrigation system. Accommodating this may increase peak flows by an order of magnitude. Where customers that have no history of usage on the potable system are to be served with reclaimed water, detailed investigations are warranted to ensure that the service provided would be compatible with the user needs. These investigations should include an interview with the system operator as well as an inspection of the existing facilities. Figure 3-14 provides a schematic of the multiple reuse conveyance and distribution systems that may be encountered. The actual requirements of a system will be dictated by the final customer base and are discussed in Chapter 2. The remainder of this section discusses issues pertinent to all reclaimed water conveyance and distribution systems. A concentration or cluster of users results in lower customer costs for both capital and O&M expenses than a delivery system to dispersed users. Initially, a primary skeletal system is generally designed to serve large institutional users who are clustered and closest to the treatment plant. A second phase may then expand the system to more scattered and smaller users, which receive nonpotable water from the central arteries of the nonpotable system. Such an approach was successfully implemented in the City of St. Petersburg, Florida. The initial customers were institutional (e.g., schools, golf courses, urban green space, and commercial). However, the lines were sized to make allowance for future service to residential customers. As illustrated in St. Petersburg and elsewhere, once reclaimed water is made available to large users, a secondary customer base of smaller users often request service. To ensure that expansion can occur to the projected future markets, the initial system design should model sizing of pipes to satisfy future customers within any given zone within the service area. At points in the system, where a future network of connections is anticipated, such as a neighborhood, turnouts should be installed. Pump stations and other major facilities involved in conveyance should be designed to allow for planned expansion. Space should be provided for additional pumps, or the capacities of the pumps may be expanded by changes to impellers and/or motor size. Increasing a pipe diameter by one size is economically justified since over

half the initial cost of installing a pipeline is for excavation, backfill, and pavement. A potable water supply system is designed to provide round-the-clock, “on-demand” service. Some nonpotable systems allow for unrestricted use, while others place limits on the hours when service is available. A decision on how the system will be operated will significantly affect system design. Restricted hours for irrigation (i.e., only evening hours) may shift peak demand and require greater pumping capacity than if the water was used over an entire day or may necessitate a programmed irrigation cycle to reduce peak demand. The Irvine Ranch Water District, California, though it is an “on-demand” system, restricts landscape irrigation to the hours of 9 p.m. to 6 a.m. to limit public exposure. Due to the automatic timing used in most applications, the peak hour demand was found to be 6 times the average daily demand and triple that of the domestic water distribution system (Young et al., 1987). The San Antonio Water System (Texas) established a requirement for onsite storage for all users with a demand greater than 100 acre-feet per year as a means of managing peak demands. As noted previously, attributes such as freeze protection may result in similar increases in peak demands of agricultural systems. System pressure should be adequate to meet the user’s needs within the reliability limits specified in a user agreement or by local ordinance. The Irvine Ranch Water District, California runs its system at a minimum of 90 psi (600 kPa). The City of St. Petersburg, Florida currently operates its system at a minimum pressure of 60 psi (400 kPa). However, the City of St. Petersburg is recommending that users install low-pressure irrigation devices, which operate at 50 psi (340 kPa) as a way of transferring to a lower pressure system in the future to reduce operating costs. The City of Orlando, Florida is designing a regional urban reuse system with a target minimum pressure in the transmission main of 50 psi (350 KPa) at peak hour conditions (CDM, 2001). When significant differences in elevations exist within the service area, the system should be divided into pressure zones. Within each zone, a maximum and minimum delivery pressure is established. Minimum delivery pressures may be as low as 10 psi (70 kPa) and maximum delivery pressures may be as high as 150 psi (1,000 kPa), depending on the primary uses of the water. Several existing guidelines recommend operating the nonpotable system at pressures lower than the potable system (i.e., 10 psi, 70 kPa lower) in order to mitigate any cross-connections. However, experience in the field indicates that this is difficult to achieve at all times throughout the distribution system.


Figure 3-14.

Example of a Multiple Reuse Distribution System

Public Health Safeguards

„ Establish that public health is the overriding concern „ Devise procedures and regulations to prevent cross-

The major concern guiding design, construction, and operation of a reclaimed water distribution system is the prevention of cross-connections. A cross-connection is a physical connection between a potable water system used to supply water for drinking purposes, and any source containing nonpotable water through which potable water could be contaminated. Another major concern is to prevent improper use or inadvertent use of reclaimed water as potable water. To protect public health from the outset, a reclaimed water distribution system should be accompanied by health codes, procedures for approval (and disconnection) of service, regulations governing design and construction specifications, inspections, and operation and maintenance staffing. Public health protection measures that should be addressed in the planning phase are identified below.


Develop a uniform system to mark all nonpotable components of the system Prevent improper or unintended use of nonpotable water through a proactive public information program nonpotable system


„ Provide for routine monitoring and surveillance of the


Establish and train special staff members to be responsible for operations, maintenance, inspection, and approval of reuse connections

„ Develop construction and design standards



Provide for the physical separation of the potable water, reclaimed water, sewer lines and appurtenances

ply with the revised wording requirements as part of the permit renewal process for FDEP (FDEP, 1999). Figure 3-15. Reclaimed Water Advisory Sign

Successful methods for implementing these measures are outlined below. a. Identification of Pipes and Appurtenances

All components and appurtenances of the nonpotable system should be clearly and consistently identified throughout the system. Identification should be through color coding and marking. The nonpotable system (i.e., pipes, pumps, outlets, and valve boxes) should be distinctly set apart from the potable system. The methods most commonly used are unique colorings, labeling, and markings. Nonpotable piping and appurtenances are painted purple or can be integrally stamped or marked, “CAUTION NONPOTABLE WATER – DO NOT DRINK” or “CAUTION: RECLAIMED WATER – DO NOT DRINK,” or the pipe may be wrapped in purple polyethylene vinyl wrap. Another identification method is to mark pipe with colored marking tape or adhesive vinyl tape. When tape is used, the words (“CAUTION: RECLAIMED WATER – DO NOT DRINK”) should be equal to the diameter of the pipe and placed longitudinally at 3-feet (0.9-meters) intervals. Other methods of identification and warning are: stenciled pipe with 2- to 3-inch (5- to 8-cm) letters on opposite sides, placed every 3 to 4 feet (0.9 to 1.2 meters); for pipe less than 2 inches (5 cm), lettering should be at least 5/8-inch (1.6 cm) at 1-foot (30-cm) intervals; plastic marking tape (with or without metallic tracer) with lettering equal to the diameter of pipe, continuous over the length of pipe at no more than 5-foot (1.5-meter) intervals; vinyl adhesive tape may be placed at the top of the pipe for diameters 2.5 to 3 inches (6 to 8 cm) and along opposite sides of the pipe for diameters 6 to 16 inches (15 to 40 cm), and along both sides and on top of the pipe for diameters of 20 inches (51 cm) or greater (AWWA, 1994). The FDEP requires all new advisory signs and labels on vaults, service boxes, or compartments that house hose bibs, along with all labels on hose bibs, valves, and outlets, to bear the words, “do not drink” and “no beber,” along with the equivalent standard international symbol. In addition to the words, “do not drink” and “no beber,” advisory signs posted at storage ponds and decorative water features also bear the words, “do not swim” and “no nadar,” along with the equivalent standard international symbols. Figure 3-15 shows a typical reclaimed water advisory sign. Existing advisory signs and labels will be retrofitted, modified, or replaced in order to com-

Valve boxes for hydraulic and electrical components should be colored and warnings should be stamped on the cover. The valve covers for nonpotable transmission lines should not be interchangeable with potable water covers. For example, the City of Altamonte Springs, Florida uses square valve covers for reclaimed water and round valve covers for potable water. Blow-off valves should be painted and carry markings similar to other system piping. Irrigation and other control devices should be marked both inside and outside. Any constraints or special instructions should be clearly noted and placed in a suitable cabinet. If fire hydrants are part of the system, they should be painted or marked and the stem should require a special wrench for opening. b. Horizontal and Vertical Separation of Potable from Nonpotable Pipes

The general rule is that a 10-foot (3-meter) horizontal interval and a 1-foot (0.3-meter) vertical distance should be maintained between potable (or sewer) lines and nonpotable lines that are parallel to each other. When these distances cannot be maintained, special authorization may be required, though a minimum lateral distance of 4 feet (1.2 meters) (St. Petersburg) is generally mandatory. The State of Florida specifies a 5-foot (1.5meter) separation between reclaimed water lines and water lines or force mains, with a minimum of 3-foot (0.9meter) separation from pipe wall to pipe wall (FDEP, 1999). This arrangement allows for the installation of reclaimed water lines between water and force mains that are separated by 10 feet (3 meters). The potable water should be placed above the nonpotable, if possible. Un-


der some circumstances, using a reclaimed water main of a different depth than that of potable or force mains might be considered to provide further protection from having an inadvertent cross–connection occur. Nonpotable lines are usually required to be at least 3 feet (90 cm) below ground. Figure 3-16 illustrates Florida’s separation requirements for nonpotable lines. c. Prevent Onsite Ability to Tie into Reclaimed Water Lines

„ Air gap „ Reduced-pressure principal backflow prevention as-


Double-check valve assembly

„ Pressure vacuum breaker „ Atmospheric vacuum breaker

The Irvine Ranch Water District, California has regulations mandating the use of special quick coupling valves for onsite irrigation connections. For reclaimed water, these valves are operated by a key with an Acme thread. This thread is not allowed for the potable system. The cover on the reclaimed water coupler is different in color and material from that used on the potable system. Hose bibs are generally not permitted on nonpotable systems because of the potential for incidental use and possible human contact with the reclaimed water. Below-ground bibs placed inside a locking box or that require a special tool to operate are allowed by Florida regulations (FDEP, 1999). d. Backflow Prevention

The AWWA recommends the use of a reduced-pressure principal backflow prevention assembly where reclaimed water systems are present. However, many communities have successfully used double-check valve assemblies. The backflow prevention device will prevent water expansion into the water distribution system. At some residences, the tightly closed residential water system can create a pressure buildup that causes the safety relief on a water heater to periodically discharge. This problem was solved by the City of St. Petersburg, Florida, by providing separate pressure release valves, which allow for the release of water through an outdoor hose bibb. If potable water is used as make-up water for lakes or reservoirs, there should be a physical break between the potable water supply pipe and receiving reservoir. The air gap separating the potable water from the reservoir containing nonpotable water should be at least 2 pipe diameters. There should never be any permanent connection between nonpotable and potable lines in the system. In most cases, backflow prevention devices are not provided on a reclaimed water system. However, the San Antonio Water System (Texas) requires a reduced-pres-

Where the possibility of cross-connection between potable and reclaimed water lines exists, backflow prevention devices should be installed onsite when both potable and reclaimed water services are provided to a user. The backflow prevention device is placed on the potable water service line to prevent potential backflow from the reclaimed water system into the potable water system if the 2 systems are illegally interconnected. Accepted methods of backflow prevention include:

Figure 3-16.

Florida Separation Requirements for Reclaimed Water Mains


sure principal backflow preventer on the potable supply to properties using reclaimed water. In addition, the City requires customers to use a double-check assembly or air gap on the reclaimed water supply. This provision is basic to maintaining a consistent water quality in the San Antonio reclaimed water supply. It is prudent to periodically inspect the potable system to confirm that crossconnections do not exist. The City of San Antonio alternately shuts down the potable and reclaimed water at a site. The inactive system is then checked for residual pressure, indicating a cross- connection. Where possible, dye tests are also conducted (Baird, 2000). The City of Altamonte Springs, Florida takes its entire reuse system off line for 2 days each year as part of its cross-connection control program. e. Safeguards when Converting Existing Potable Lines to Nonpotable Use

In cases where parts of the system are being upgraded and some of the abandoned potable water lines are being transferred to the nonpotable system, care must be taken to prevent any cross-connections from occurring. As each section is completed, the new system should be shutdown and drained and each water user checked to ensure that there are no improper connections. Additionally, a tracer, such as potassium permanganate, may be introduced into the nonpotable system to test whether any of it shows up at any potable fixture. In existing developments where an in-place irrigation system is being converted to carry reclaimed water, the new installation must be inspected and tested with tracers or some other method to ensure separation of the potable from the nonpotable supply. It may warrant providing a new potable service line to isolated potable facilities. For example, if a park is converting to reclaimed water, rather than performing an exhaustive evaluation to determine how a water fountain was connected to the existing irrigation system, it could be simpler to supply a new service lateral from the new water main. Operations and Maintenance

Differences in maintenance procedures for potable and nonpotable systems cannot generally be forecast prior to the operation of each system. For instance, the City of St. Petersburg, Florida flushes its nonpotable lines twice a year during the off-season months. The amount of water used in the flushing is equal to a day’s demand of reclaimed water. The Irvine Ranch Water District (California) reports no significant difference in the 2 lines, though the reclaimed lines are flushed more frequently (every 2 to 3 years versus every 5 to 10 years for potable) due to suspended matter and sediment picked up during lake storage. Verification that adequate disinfection has occurred as part of treatment prior to distribution to reclaimed water customers is always required. However, maintenance of a residual in the transmission/distribution system is not required. Florida requires a 1-mg/ l chlorine residual at the discharge of the chlorine contact basin, but no minimum residual is required in the reclaimed water piping system. The State of Washington is an exception in that it does require a minimum of 0.5mg/l-chlorine residual in the distribution lines. a. Blow-Offs/Flushing Hydrants

Even with sufficient chlorination, residual organics and bacteria may grow at dead spots in the system, which may lead to odor and clogging problems. Flushing and periodic maintenance of the system can significantly allay the problem. In most cases, the flushing flow is directed into the sewage system. b. Flow Recording

Even when a system is unmetered, accurate flow recording is essential to manage the growth of the system. Flow data are needed to confirm total system use and spatial distribution of water supplied. Such data allow for efficient management of the reclaimed water pump stations and formulations of policies to guide system growth. Meters placed at the treatment facility may record total flow and flow-monitoring devices may be placed along the system, particularly in high consumption areas. c. Permitting and Inspection

Maintenance requirements for the nonpotable components of the reclaimed water distribution system should be the same as those for potable. As the system matures, any disruption of service due to operational failures will upset the users. From the outset, such items as isolation valves, which allow for repair to parts of the system without affecting a large area, should be designed into the nonpotable system. Flushing the line after construction should be mandatory to prevent sediment from accumulating, hardening, and becoming a serious future maintenance problem.

The permitting process includes plan and field reviews followed by periodic inspections of facilities. This oversight includes inspection of both onsite and offsite facilities. Onsite facilities are the user’s nonpotable water facilities downstream from the reclaimed water meter. Offsite facilities are the agency’s nonpotable water facilities up to and including the reclaimed water meter.


Though inspection and review regulations vary from system to system, the basic procedures are essentially the same. These steps are described below. (1) Plan Review – A contractor (or resident) must request service and sign an agreement with the agency or department responsible for permitting reclaimed water service. Dimensioned plans and specifications for onsite facilities must conform to regulations. Usually, the only differences from normal irrigation equipment will be identification requirements and special appurtenances to prevent cross-connections. Some systems, however, require that special strainer screens be placed before the pressure regulator for protection against slime growths fouling the sprinkler system, meter, or pressure regulator. The plans are reviewed and the agency works with the contractor to make sure that the system meets all requirements. Systems with crossconnections to potable water systems must be denied. Temporary systems should not be considered. Devices for any purpose other than irrigation should be approved through special procedures. Installation procedures called out on the plan notes are also reviewed because they provide the binding direction to the landscape contractor. All points of connection are reviewed for safety and compatibility. The approved record drawings (“as-builts”) are kept on file. The “asbuilts” include all onsite and offsite nonpotable water facilities as constructed or modified, and all potable water and sewer lines. (2) Field Review – Field review is generally conducted by the same staff involved in the plan review. Staff looks for improper connections, unclear markings, and insufficient depths of pipe installation. A cross-connection control test is performed, followed by operation of the actual onsite irrigation system to ensure that overspraying and overwatering are not occurring. Any problems identified are then corrected. Follow-up inspections are routine, and in some cases, fixed interval (e.g. semi-annual) inspections and random inspections are planned. (3) Monitoring – A number of items should be carefully monitored or verified, including:

mal education to their personnel so that these contractors are familiar with the regulations governing reclaimed water installations
„ Submitting all modifications to approved fa-

cilities to the responsible agencies

Detecting and recording any breaks in the transmission main Randomly inspecting user sites to detect any faulty equipment or unauthorized use system to test pressure, chlorine residual, and other water quality parameters


„ Installing monitoring stations throughout the

A reclaimed water supplier should reserve the right to withdraw service for any offending condition subject to correction of the problem. Such rights are often established as part of a user agreement or a reuse ordinance. Chapter 5 provides a discussion of the legal issues associated with reclaimed water projects.


Operational Storage

As with potable water distribution systems, a reclaimed water system must provide sufficient operational storage to accommodate diurnal fluctuations in demand and supply. The volume required to accommodate this task will depend on the interaction of the supply and demand over a 24-hour period. Designs are dependent on assessments of the diurnal demand for reclaimed water. Such assessments, in most cases, require a detailed investigation of the proposed user or users. When possible, records of actual historical use should be examined as a means to develop demand requirements. Where records are absent, sitespecific investigations are in order. In some cases, pilot studies may be warranted prior to initiating a full-scale reuse program. Figure 3-17 presents the anticipated diurnal fluctuation of supply and urban irrigation demand for a proposed reclaimed water system in Boca Raton, Florida (CDM, 1991). This information was developed based on the historic fluctuations in wastewater flow experienced in Boca Raton and the approximate fluctuations in the reclaimed water urban irrigation demand experienced in the St. Petersburg, Florida urban reuse program. Operational storage may be provided at the reclamation facility, as remote storage out in the system, or as a combination of both. For example, the City of Altamonte

Requiring that landscape contractors or irrigation contractors provide at least mini-


Figure 3-17.

Anticipated Daily Reclaimed Water Demand Curve vs. Diurnal Reclaimed Water Flow Curve

Springs, Florida, maintains ground storage facilities at the reclamation plant and elevated storage tanks out in the reclaimed water system. Large sites, such as golf courses, commonly have onsite ponds capable of receiving water throughout the day. Such onsite facilities reduce operational storage requirements that need to be provided by the utility. In the City of Naples, Florida where reclaimed water is provided to 9 golf courses, remote booster pump stations deliver reclaimed water to users from a covered storage tank located at the reclamation plant. Operational storage facilities are generally covered tanks or open ponds. Covered storage in ground or elevated tanks is used for unrestricted urban reuse where aesthetic considerations are important. Ponds are less costly, in most cases, but generally require more land per gallon stored. Where property costs are high or sufficient property is not available, ponds may not be feasible. Open ponds also result in water quality degradation from biological growth, and chlorine residual is difficult to maintain. Ponds are appropriate for onsite applications such as agricultural and golf course irrigation. In general, ponds that are already being used as a source for irrigation are also appropriate for reclaimed water storage. In addition to the biological aspects of storing reclaimed water in onsite impoundments, the concentration of various constituents due to surface evaporation may present a problem. Reclaimed water often has a more elevated concentration of TDS than other available sources of water. Where evaporation rates are high

and rainfall is low, the configuration of onsite storage ponds was found to have significant impacts on water quality in terms of TDS (Chapman and French, 1991). Shallow ponds with a high area-to-volume ratio experience greater concentrations of dissolved solids due to surface evaporation. Dissolved solids increase in all ponds, but deeper ponds can mitigate the problem. Figure 3-18 summarizes the expected concentration levels of TDS with varying pond depth for reclaimed water with an influent concentration of 1,112 and 1,500 mg/l of TDS, assuming water is lost from storage through evaporation only.


Alternative Disposal Facilities

Beneficial water reclamation and reuse can effectively augment existing water supplies and reduce the water quality impacts of effluent discharge. Yet 100 percent reuse of the effluent may not always be feasible. In such cases, some form of alternative use or disposal of the excess water is necessary. For the purposes of this section, the discharge of reclaimed water will be considered “disposal,” regardless of whether it is for subsequent reuse or permanent disposal. Where reclamation programs incorporate existing wastewater treatment facilities, an existing disposal system will likely be in place and can continue to be used for partial or intermittent disposal. Common alternative disposal systems include surface water discharge, injection wells, land application, and wetlands application.


Figure 3-18.

TDS Increase Due to Evaporation for One Year as a Function of Pond Depth

In the City of Petaluma, California the ability to protect the downstream habitat by eliminating surface water discharges from May through September played a major role in considering reuse. (Putnam, 2002). Injection Wells

Injection wells, which convey reclaimed water into subsurface formations, are also used as an alternative means of disposal, including eventual reuse via groundwater recharge. Thus, the purpose of the disposal (permanent or for future reuse) will typically determine the type and regulatory framework of the injection wells. The EPA Underground Injection Control (UIC) program has categorized injection wells into 5 classes, only 2 of which (Class I and V) apply to reclaimed water disposal. Class I injection wells are technologically sophisticated and inject hazardous and non-hazardous wastes below the lowermost underground source of drinking water (USDW). Injection occurs into deep, isolated rock formations that are separated from the lowermost USDW by layers of impermeable clay and rock. In general, owners and operators of most new Class I injection wells are required to:

These methods are described below. Surface Water Discharge

Intermittent surface water discharge may provide an acceptable method for the periodic disposal of excess reclaimed water. While demand for reclaimed water normally declines during wet weather periods, it is during wet weather periods that surface waters are generally more able to assimilate the nutrients in reclaimed water without adverse water quality impacts. Conversely, during the warm summer months when surface water bodies are often most susceptible to the water quality impacts of effluent discharges, the demand for irrigation water is high and an excess of reclaimed water is less likely. Thus, the development of a water reuse program with intermittent discharges can reduce or eliminate wastewater discharges during periods when waters are most sensitive to nutrient concentrations while allowing for discharges at times when adverse impacts are less likely. By eliminating discharges for a portion of the year through water reuse, a municipality may also be able to avoid the need for costly advanced wastewater treatment nutrient removal processes often required for a continuous discharge. The New York City’s investigation into water reclamation included a comparison of the reduction in nitrogen loadings that could be achieved through BNR treatment or beneficial reuse. Table 3-15 provides a summary of this effort and indicates the volume of water that must be diverted to reuse in order to equal the nutrient reduction that would be realized from a given level of BNR treatment.

Site the injection wells in a location that is free of faults and other adverse geological features. Drill to a depth that allows the injection into formations that do not contain water that can potentially be used as a source of drinking water. These injection zones are confined from any formation that may contain water that may potentially be used as a source of drinking water. inside another pipe (casing). This outer pipe has cement on the outside to fill any voids occurring between the outside pipe and the hole that was bored for the well (borehole). This allows for multiple layers of containment of the potentially contaminating injection fluids.

„ Inject through an internal pipe (tubing) that is located

„ Test for integrity at the time of completion and every

5 years thereafter (more frequently for hazardous waste wells).

Monitor continuously to assure the integrity of the well.

Class V injection wells will likely include nearly all reclaimed water injection wells that are not permitted as Class I injection wells. Under the existing federal regulations, Class V injection wells are “authorized by rule” (40 CFR 144), which means they do not require a federal


permit if they do not endanger underground sources of drinking water and comply with other UIC program requirements. However, individual states may require specific treatment, well construction, and water quality monitoring standards compliance before permitting any injection of reclaimed water into aquifers that are currently or could potentially be used for potable supply. A discussion about potential reclaimed water indirect potable reuse guidelines is contained in Chapter 4. Injection wells are a key component of the urban reuse program in the City of St. Petersburg, Florida. The city operates 10 wells, which inject excess reclaimed water into a saltwater aquifer at depths between 700 and 1,000 feet (210 and 300 meters) below the land surface. Approximately 50 percent of the available reclaimed water is disposed of through injection. When originally installed, the wells were permitted as Class I injection wells with the primary use for the management of excess reclaimed water, but also were employed to dispose of any reclaimed water not meeting water quality standards. The City is in the permitting process to convert the wells to Class V injection wells, for primary use as an ASR system. Under suitable circumstances, excess reclaimed water can be stored in aquifers for subsequent reuse. In Orange County, California injection of reclaimed water into potable supply aquifers has been conducted for seawater intrusion control and groundwater recharge since 1976 and has expanded in recent years to Los Angeles County, California. New advanced water treatment and injection projects are underway in both counties to supply the majority of coastal injection wells in Orange and Los Angeles counties with reclaimed water to reduce dependence on imported water from the Colorado River and northern California. Additional discussion about reclaimed water recharge can be found in Chapter 2.

Land Application

In water reuse irrigation systems, reclaimed water is applied in quantities to meet an existing water demand. In land treatment systems, effluent may be applied in excess of the needs of the crop. Land application systems can provide reuse benefits, such as irrigation and/or groundwater recharge. However, in many cases, the main focus of land application systems is to avoid detrimental impacts to groundwater that can result from the application of nutrients or toxic compounds. In some cases, a site may be amenable to both reuse and “land application”. Such are the conditions of a Tallahassee, Florida sprayfield system. This system is located on a sand ridge, where only drought-tolerant flora can survive without irrigation. By providing reclaimed water for irrigation, the site became suitable for agricultural production of multiple crop types. However, because of the extreme infiltration and percolation rates, it is possible to apply up to 3 inches per week (8 cm per week) of reclaimed water without significant detrimental impacts to the crop (Allhands and Overman, 1989). The use of land application as an alternative means of disposal is subject to hydrogeological considerations. The EPA manual Land Treatment of Municipal Wastewater (U.S. EPA, 1981) provides a complete discussion of the design requirements for such systems. The use of land application systems for wet weather disposal is limited unless high infiltration and percolation rates can be achieved. This can be accomplished through the use of rapid infiltration basins or manmade wetlands. In cases where manmade wetlands are created, damaged wetlands are restored, or existing wetlands are en-

Table 3-15.

Nitrogen Mass Removal Strategies: Nutrient Removal vs. Water Reuse
Enhance d Ste p Fe e d BNR & Se parate Ce ntrate Tr e atm e nt (lbs /d) 12,500 9,500 3,500 6,500 5,000

Wate r Pollution Control Facility

1998 Total Flow (m gd)

1998 Efflue nt TN (lbs /d)

Ste p Fe e d BNR Proje cte d TN Dis charge (lbs /d) 24,000 16,000 3,500 11,000 7,500

Equivale nt Wate r Re us e (m gd) 39 22 33 56 36

Equivale nt Wate r Re us e (m gd) 128 67 33 85 48

Wards Island Hunts Point Tallman Island Bowery Bay 26 Ward

224 134 59 126 69

29,000 19,000 7,700 19,700 15,500


hanced, wetlands application may be considered a form of water reuse, as discussed in Section 2.5.1. Partial or intermittent discharges to wetlands systems have also been incorporated as alternative disposal means in water reuse systems, with the wetlands providing additional treatment through filtration and nutrient uptake. A wetlands discharge is used in Orange County, Florida, where a portion of the reclaimed water generated by the Eastern Service Area WWTF is reused for power plant cooling, and the remainder is discharged by overland flow to a system of manmade and natural wetlands. Figure 3-19 shows the redistribution construction wetlands system. Application rates are managed to simulate natural hydroperiods of the wetland systems (Schanze and Voss, 1989).

vestigation of environmental impacts is required, it may be subject to state policies. The following conditions are given as those that would induce an EIS in a federally-funded project:
„ „

The project may significantly alter land use. The project is in conflict with any land use plans or policies. Wetlands will be adversely impacted.


„ Endangered species or their habitat will be affected. „


Environmental Impacts

The project is expected to displace populations or alter existing residential areas. The project may adversely affect a flood plain or important farmlands. The project may adversely affect parklands, preserves, or other public lands designated to be of scenic, recreational, archaeological, or historical value. The project may have a significant adverse impact upon ambient air quality, noise levels, surface or groundwater quality or quantity. The project may have adverse impacts on water supply, fish, shellfish, wildlife, and their actual habitats.

Elimination or reduction of a surface water discharge by reclamation and reuse generally reduces adverse water

Figure 3-19.

Orange County, Florida, Redistribution Constructed Wetland


The types of activities associated with federal EIS requirements are outlined below. Many of the same requirements are incorporated into environmental assessments required under state laws.

quality impacts to the receiving water. However, moving the discharge from a disposal site to a reuse system may have secondary environmental impacts. An environmental assessment may be required to meet state or local regulations and is required whenever federal funds are used. Development of water reuse systems may have unintended environmental impacts related to land use, stream flow, and groundwater quality. Formal guidelines for the development of an environmental impact statement (EIS) have been established by the EPA. Such studies are generally associated with projects receiving federal funding or new NPDES permits and are not specifically associated with reuse programs. Where an in-

Land Use Impacts

Water reuse can induce significant land use changes, either directly or indirectly. Direct changes include shifts in vegetation or ecosystem characteristics induced by alterations in water balance in an area. Indirect changes include land use alterations associated with industrial, residential, or other development made possible by the added supply of water from reuse. Two cases from Florida illustrate this point.
„ A study in the Palm Beach County, Florida area de-

termined that reuse could provide water supply sufficient to directly and substantially change the hydroperiod in the area. This change was significant enough to materially improve the potential for sus-


taining a wetlands ecosystem and for controlling the extent and spread of invasive species. In short, the added reuse water directly affected the nature of land cover in the area.

for irrigation or other purposes can cause an increase in base flows, if the prevailing groundwater elevation is raised. (Groundwater effects are discussed further in Section 3.7.3.)

Indirect changes were also experienced in agricultural land use in the Orange County, Florida area. Agricultural use patterns were found to be materially influenced by water reuse associated with the Water Conserv II project. Commercial orange groves were sustained and aided in recovery from frost damage to crops by the plentiful supply of affordable water generated by reuse. The added reuse water affected the viability of agriculture, and therefore, indirectly affected land use in the area.

Increases in stream flows during wet periods can result from reduced soil moisture capacity in a tributary watershed, if there is pervasive use of recharge on the land surface during dry periods. In such a case, antecedent conditions are wetter, and runoff greater, for a given rainstorm. The instream system bears the consequences of this change.

It is important to note that the concurrent effects of land use changes discussed in Section 3.7.1 can exacerbate either of the above effects. Instream flow reduction is also possible, and can be more directly evident. For example, the Trinity River in Texas, in the reaches near the City of Dallas, maintains a continuous flow of several hundred cubic feet per second during dry periods. This flow is almost entirely composed of treated effluent from discharges further upstream. If extensive reuse programs were to be implemented at the upstream facilities, dry weather flows in this river would be jeopardized and plans for urban development downstream could be severely impacted due to lack of available water. In addition to water quantity issues, reuse programs can potentially impact aesthetics or recreational use and damage ecosystems associated with streams where hydrologic behavior is significantly affected. Where wastewater discharges have occurred over an extended period of time, the flora and fauna can adapt and even become dependent on that water. A new or altered ecosystem can arise, and a reuse program implemented without consideration of this fact could have an adverse impact on such a community. In some cases, water reuse projects have been directly affected by concerns for instream flow reduction that could result from a reuse program. The San Antonio Water System (SAWS) in Texas defined the historic spring flow at the San Antonio River headwaters during development of their reclaimed water system. In cooperation with downstream users and the San Antonio River Authority, SAWS agreed to maintain a release of 55,000 acre-feet per year (68 x 106 m3 per year) from its water reclamation facilities. This policy protects and enhances downstream water quality and provides 35,000 acre-feet per year (43 x 106 m3 per year) of reclaimed water for local use. In the State of Washington, reuse water can be discharged to a stream as stream flow augmentation. Un-

Other examples of changes in land use as a result of available reuse water include the potential for urban or industrial development in areas where natural water availability limits the potential for growth. For example, if the supply of potable water can be increased through recharge using reuse supply, then restrictions to development might be reduced or eliminated. Even nonpotable supplies, made available for uses such as residential irrigation, can affect the character and desirability of developed land in an area. Similar effects can also happen on a larger scale, as municipalities in areas where development options are constrained by water supply might find that nonpotable reuse enables the development of parks or other amenities that were previously considered to be too costly or difficult to implement. Commercial users such as golf courses, garden parks, or plant nurseries have similar potential for development given the presence of reuse supplies. The potential interactions associated with land use changes are complex, and in some cases the conclusion that impacts are beneficial is subjective. An increase in urban land use, for example, is not universally viewed as a positive change. For this reason, the decision-making process involved in implementing a reclamation program should result from a careful consideration of stakeholder goals.


Stream Flow Impacts

Instream flows can either increase or decrease as a consequence of reuse projects. In each situation where reuse is considered, there is the potential to shift water balances and effectively alter the prevailing hydrologic regime in an area. Two examples of the way flows can increase as a result of a reuse project are as follows:
„ In streams where dry weather base flows are ground-

water dependant, land application of reclaimed water


der this provision, reclaimed water can be discharged to surface water for purposeful uses such as:


Case Studies
Code of Good Practices for Water Reuse

If the flow is to maintain adequate flows for aquatic life and therefore the stream is acting as a conduit

„ If the reclaimed water is going to be used downstream

In the City of Sequim, Washington 0.1 cfs (2.8 l/s) of reclaimed water is discharged into the Bell Stream to keep the benthic layer wet. The flow is not intended to maintain an environment for fish, but instead to maintain other small species that live in the streambed. To date, no studies have been conducted to show the effects to the ecosystem. The implication of these considerations is that a careful analysis of the entire hydrologic system is an appropriate consideration in a reuse project if instream impacts are to be understood. This is particularly the case when the magnitude of the flows impacted by the reuse program is large, relative to the quantities involved in the hydrologic system that will be directly impacted by the reuse program.

The Florida Department of Environmental Protection (FDEP) and the Florida Water Environment Association’s (FWEA) Water Reuse committee have developed the Code of Good Practices for Water Reuse in Florida (FDEP, 2002). The Code of Good Practices includes 16 principles and is designed to aid reuse utilities as they implement quality water reuse programs. Protection of Public Health and Environmental Quality Public Health Significance – To recognize that distribution of reclaimed water for nonpotable purposes offers potential for public contact and that such contact has significance related to the public health. Compliance – To comply with all applicable state, federal, and local requirements for water reclamation, storage, transmission, distribution, and reuse of reclaimed water. Product – To provide reclaimed water that meets state treatment and disinfection requirements and that is safe and acceptable for the intended uses when delivered to the end users. Quality Monitoring and Process Control – To continuously monitor the reclaimed water being produced and rigorously enforce the approved operating protocol such that only high-quality reclaimed water is delivered to the end users. Effective Filtration – To optimize performance of the filtration process in order to maximize the effectiveness of the disinfection process in the inactivation of viruses and to effectively remove protozoan pathogens. Cross-Connection Control – To ensure that effective cross-connection control programs are rigorously enforced in areas served with reclaimed water. Inspections – To provide thorough, routine inspections of reclaimed water facilities, including facilities located on the property of end users, to ensure that reclaimed water is used in accordance with state and local requirements and that cross-connections do not occur.


Hydrogeological Impacts

As a final environmental consideration of water reuse, the groundwater quality effects of the reclaimed water for the intended use must be reviewed. The exact concerns of any project are evaluated on a case-by-case basis. One of the better-known sources of potential groundwater pollution is nitrate, which may be found in, or result from, the application of reclaimed water. However, additional physical, chemical, and biological constituents found in reclaimed water may pose an environmental risk. In general, these concerns increase when there are significant industrial wastewater discharges to the water reclamation facility. Impacts of these constituents are influenced by the hydrogeology of the reuse application site. Where karst conditions exist, for example, constituents may potentially exist within the reclaimed water that will ultimately reach the aquifer. In many reclaimed water irrigation programs, a groundwater-monitoring program is required to detect the impacts of reclaimed water constituents.


Reuse System Management Water Supply Philosophy – To adopt a “water supply” philosophy oriented towards reliable delivery of a high-quality reclaimed water product to the end users. Conservation – To recognize that reclaimed water is a valuable water resource, which should be used efficiently and effectively to promote conservation of the resource. Partnerships – To enter into partnerships with the Department of Environmental Protection, the end users, the public, the drinking water utility, other local and regional agencies, the water management district, and the county health department to follow and promote these practices. Communications – To provide effective and open communication with the public, end users, the drinking water utility, other local and regional agencies, the Department of Environmental Protection, the water management district, and the county health department. Contingency Plans – To develop response plans for unanticipated events, such as inclement weather, hurricanes, tornadoes, floods, drought, supply shortfalls, equipment failure, and power disruptions. Preventative Maintenance – To prepare and implement a plan for preventative maintenance for equipment and facilities to treat wastewater and to store, convey, and distribute reclaimed water. Continual Improvement – To continually improve all aspects of water reclamation and reuse. Public Awareness Public Notification – To provide effective signage advising the public about the use of reclaimed water and to provide effective written notification to end users of reclaimed water about the origin of, the nature of, and proper use of reclaimed water. Education – To educate the public, children, and other agencies about the need for water conservation and reuse, reuse activities in the state and local area, and environmentally sound wastewater management and water reuse practices.


Examples of Potable Water Separation Standards from the State of Washington

Efforts to control cross-connections invariably increase as part of the implementation of dual distribution systems involving potable and nonpotable lines. A fundamental element of these cross-connection control elements is the maintenance of a separation between potable and nonpotable pipelines. While the specific requirements often vary from state to state, common elements typically include color-coding requirements as well as minimum vertical and horizontal separations. Excerpts from the State of Washington, “Reclaimed Water – Potable Water Separation Standards,” are provided below as an example of these requirements. Policy Requirements: Potable water lines require protection from any nonpotable water supply, including all classes of reclaimed water. For buried pipelines, proper pipe separation must be provided. General Requirements: Standard potable-nonpotable pipe separation standards should be observed at: 1. 2. Parallel Installations: Minimum horizontal separation of 10 feet (3 meters) pipe-to-pipe. Pipe Crossings: Minimum vertical separation of 18 inches (0.5 meters) pipe-to-pipe, with potable lines crossing above nonpotable.

Special Conditions: Special laying conditions where the required separations cannot be maintained may be addressed as shown in the following examples. Figure 3-20. A Minimum 5-foot (1.5-meter) Horizontal Pipe Separation Coupled with an 18-inch (46-cm) Vertical Separation


Figure 3-21.

Irrigation Lateral Separation

Special Condition Number 2 - Inadequate Horizontal Separation: Site limitations will likely result in parallel pipe installations with less than 48 inches (1.2 meters) of pipe-to-pipe separation. In these instances, a minimum pipe-to-pipe separation of 18 inches (46 cm) shall be provided, and the reclaimed water irrigation lateral shall be installed a minimum of 18 inches (46 cm) above the potable water pipeline. An impervious barrier, such as PVC sheeting, installed between the irrigation lateral and the waterline for the length of the run is recommended. Figure 3-23. Parallel Water - Lateral Installation

Pipeline Separation: Minimum pipeline separation between any potable water line and reclaimed water irrigation laterals shall be 48 inches (1.2 meters) pipe-to-pipe separation. Special Condition Number 1- Irrigation Lateral Crossings: Reclaimed water irrigation laterals will commonly cross above potable water lines due to normal depths of bury. To provide adequate protection, the reclaimed water irrigation lateral shall be cased in pressure-rated pipe to a minimum distance of 4 feet (1.2 meters) on each side of the potable water line. Figure 3-22. Lateral Crossing Requirements


An Example of Using Risk Assessment to Establish Reclaimed Water Quality

Historically, the microbiological quality of both wastewater effluents and reclaimed water has been based on indicator organisms. This practice has proved to be effective and will likely continue into the foreseeable future. However, given uncertainties in the use of indicator organisms to control pathogens in reclaimed water and in other waters, regulatory agencies could consider developing a number of guidelines or standards for selected pathogens using microbiological risk assessment. Development of risk-based guidelines or standards could include: 1. 2. 3. Selection of appropriate pathogens Selection of microbial risk models Structuring of exposure scenarios


4. 5.

Selection of acceptable risk levels Calculation of the concentration of the pathogen that would result in a risk equal to the acceptable level of risk

As an example, York and Walker-Coleman (York and Walker-Coleman, 1999, 2000) used a risk assessment approach to evaluate guidelines for nonpotable reuse activities. These investigations developed guidelines for Giardia, Cryptosporidium, and enteroviruses using the following models:
Organism Echovirus 12 (moderately infective) Rotavirus (highly infective) Cryptosporidium Giardia Model Used Pi = 1 - (1 + N/β ) (beta-Poisson) Pi = 1 - (1 + N/β ) (beta-Poisson) Pi = 1 – e-rN (exponential) Pi = 1 – e
-rN -α -α

of 365 days during the year. In addition, a worst-case scenario involving ingestion of 100 ml of reclaimed water on a single day during the year was evaluated. These exposure scenarios were judged representative of the use of reclaimed water to irrigate a residential lawn. The exposure scenarios could be adjusted to fit other reuse activities, such as irrigation of a golf course, park, or school. The results of this exercise are summarized in Table 3-16. It is important to note that, particularly for the protozoan pathogens, the calculations assume that all pathogens present in reclaimed water are intact, viable, and fully capable of causing infection. A Giardia infectivity study conducted by the Los Angeles County Sanitation District (Garcia et al., 2002) demonstrated that Giardia cysts passing through a water reclamation facility were not infectious. This basic approach could be applied to other waters and could be used to establish consistency among the various water programs.

Parameters α = 0.374 β = 186.7 α = 0.26 β = 0.42 r = 0.00467 r = 0.0198




Source: Rose and Carnahan, 1992, Rose et al., 1996 Since specific types of viruses typically are not quantified when assessing viruses in reclaimed water, assumptions about the type of viruses present were required. For the purpose of developing a risk assessment model, it was assumed that all viruses would be highly infective rotaviruses. Helminths were not evaluated, since data from St. Petersburg, Florida showed that helminths were consistently removed in the secondary clarifiers of a water reclamation facility (Rose and Carnahan, 1992, Rose et al., 1996). In this analysis, an annual risk of infection of 1x10-4 was used as the “acceptable level of risk.” Two exposure scenarios were evaluated. Average conditions were evaluated based on the assumption that an individual would ingest 1.0 ml of reclaimed water (or its residue) on each Table 3-16.

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Average and Maximum Conditions for Exposure

Organism Giardia Cryptosporidium Enterovirus (a)

Units Viable, infectious cysts/100 l Viable, infectious oocysts/100 l PFU/100 l

Calculated Allowable Concentrations Average 1.4 5.8 0.044 Maximum 5 22 0.165

Note: (a) Assumes all viruses are highly infective Rotavirus. Source: York and Walker-Coleman, 1999, 2000


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124503. Environmental Monitoring and Support Laboratory. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1981. Process Design Manual: Land Treatment of Municipal Wastewater. EPA 625/1-81-013. EPA Center for Environmental Research Information. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1980b. Wastewater Aerosols and Disease. Proceedings of Symposium. September 19-21, 1979. EPA-600/9-80-028, NTIS No. PB81-169864. U.S. Environmental Protection Agency, Health Effects Research Laboratory. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1979a. Handbook for Analytical Quality Control in Water and Wastewater Laboratories. EPA-600/4-79-019. Environmental Monitoring and Support Laboratory. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1983. Methods for Chemical Analysis of Water and Wastes. EPA-600/ 4-79-020, NTIS No. PB84-128677. Environmental Monitoring and Support Laboratory. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1976. Quality Criteria for Water. U.S. Environmental Protection Agency. Washington, D.C. U.S. Environmental Protection Agency. 1974. Design Criteria for Mechanical, Electric, and Fluid Systems and Component Reliability. EPA-430-99-74-01. EPA Office of Water Program Operations, Municipal Construction Division. Washington, D.C. University of California Division of Agriculture and Natural Resources. 1985. Turfgrass Water Conservation Projects: Summary Report. Washington, D.C. Vickers, A., 2001. Handbook of Water Use and Conservation. Waterplow Press. Amherst, Massachusetts. Walker-Coleman, L.; D.W. York; and P. Menendez. 2002. “Protozoan Pathogen Monitoring Results for Florida’s Reuse Systems.” Proceedings of Symposium XVII. WateReuse Association. Orlando, Florida. Waller, T. 1980. Sensitivity of Encephalitozoon cuniculi to Various Temperatures, Disinfectants and Drugs. Lab. Anim. Sci. 13:277-285. Washington State Department of Ecology. 2003. “Water Reclamation and Reuse Program General Sewer and

Facility Plan Development Reliability Assessment Guidance.” Water Environment Federation. 2003. Summary of WERF Workshop on Indicators for Pathogens in Wastewater, Stormwater and Biosolids, San Antonio, TX, December 11-12, 2003. Water Environment Federation. 1998. Design of Municipal Wastewater Treatment Plants. WEF Manual of Practice No. 8, Fourth Edition, Water Environment Federation, Alexandria, Virginia. Water Environment Federation. 1996. Wastewater Disinfection Manual of Practice FD-10. Water Environment Federation. Alexandria, Virginia. Water Environment Research Foundation. 2003. Summary of WERF Workshop on Indicators for Pathogens in Wastewater, Stormwater, and Biosolids. San Antonio, Texas. December 11-12, 2003. Water Environment Research Foundation. 1995. Disinfection Comparison of UV Irradiation to Chlorination: Guidance for Achieving Optimal UV Performance (Final Report). Project 91-WWD-1. Water Environment Research Foundation. Alexandria, Virginia. Water Pollution Control Federation. 1989. Water Reuse (Second Edition). Manual of Practice SM-3. Water Pollution Control Federation. Alexandria, Virginia. Withers, B., and S. Vipond. 1980 Irrigation Design and Practice. Cornell University Press. Ithaca, New York. Wolk, D.M., C.H. Johnson, E.W. Rice, M.M. Marshall, K.F. Grahn, C.B. Plummer, and C.R. Sterling. 2000. “A Spore Counting Method and Cell Culture Model for Chlorine Disinfection Studies of Encephalitozoon syn. Septata intestinali.” Applied and Environmental Microbiology, 66:1266-1273. Woodside, G.D., and Wehner, M.P. 2002. “Lessons Learned from the Occurrence of 1,4-dioxane at Water Factory 21 in Orange County Califorina.” Proceedings of the 2002 Water Reuse Annual Symposium. Alexandria, Virginia. WateReuse Association, 202: CD-ROM. York, D.W., and L. Walker-Coleman. 1999. “Is it Time for Pathogen Standards?” Proceedings of the 1999 Florida Water Resources Conference . AWWA, FPCA, and FW&PCOA. Tallahassee, Florida.


York, D.W., L. Walker-Coleman, and P. Menendez. 2002. “Pathogens in Reclaimed Water: The Florida Experience.” Proceedings of Water Sources 2002. AWWA and WEF. Las Vegas, NV. York, D.W., and L. Walker-Coleman. 2000. “Pathogen Standards for Reclaimed Water.” Water Environment & Technology. 12(1): 58. York, D.W., and L. Walker-Coleman. 1999. “Is it Time for Pathogen Standards?” Proceedings of the 1999 Florida Water Resources Conference. AWWA, FPCA and FW&PCOA. April 25-28, 1999. Tallahassee, Florida. York, D.W., and N.R. Burg. 1998. “Protozoan Pathogens: A Comparison of Reclaimed Water and Other Irrigation Waters.” Proceedings of Water Reuse 98. AWWA and WEF. Lake Buena Vista, Florida. Young, R., K. Thompson, and C. Kinner. 1997. “Managing Water Quality Objectives in a Large Reclaimed Water Distribution System.” Proceedings for the Water Environment Federation, 70th Annual Conference and Exposition. October 18-22, 1997. Chicago, Illinois.3 Young, R.E., K. Lewinger, and R. Zenik. 1987. “Wastewater Reclamation – Is it Cost Effective? Irvine Ranch Water District – A Case Study.” Proceedings of the Water Reuse Symposium IV. August 2-7, 1987. AWWA Research Foundation. Denver, Colorado.



CHAPTER 4 Water Reuse Regulations and Guidelines in the U.S.

Most reuse programs operate within a framework of regulations that must be addressed in the earliest stages of planning. A thorough understanding of all applicable regulations is required to plan the most effective design and operation of a water reuse program and to streamline implementation. Regulations refer to actual rules that have been enacted and are enforceable by government agencies. Guidelines, on the other hand, are not enforceable but can be used in the development of a reuse program. Currently, there are no federal regulations directly governing water reuse practices in the U.S. Water reuse regulations and guidelines have, however, been developed by many individual states. As of November 2002, 25 states had adopted regulations regarding the reuse of reclaimed water, 16 states had guidelines or design standards, and 9 states had no regulations or guidelines. In states with no specific regulations or guidelines on water reclamation and reuse, programs may still be permitted on a case-bycase basis. Regulations and guidelines vary considerably from state to state. States such as Arizona, California, Colorado, Florida, Georgia, Hawaii, Massachusetts, Nevada, New Jersey, New Mexico, North Carolina, Ohio, Oregon, Texas, Utah, Washington, and Wyoming have developed regulations or guidelines that strongly encourage water reuse as a water resources conservation strategy. These states have developed comprehensive regulations or guidelines specifying water quality requirements, treatment processes, or both, for the full spectrum of reuse applications. The objective in these states is to derive the maximum resource benefits of the reclaimed water while protecting the environment and public health. Other states have developed water reuse regulations with the primary intent of providing a disposal alternative to discharge to surface waters, without considering the management of reclaimed water as a resource. This section provides an inventory of the various state water reuse regulations throughout the U.S. and updates

recommended guidelines that may aid in the development of more comprehensive state or even federal standards for water reuse. Water reuse outside the U.S. is discussed in Chapter 8.


Inventory of Existing State Regulations and Guidelines

The following inventory of state reuse regulations and guidelines is based on a survey of all states conducted specifically for this document. Regulatory agencies in all 50 states were contacted and information was obtained concerning their regulations governing water reuse. All of the information presented in this section is considered current as of November 2002. California and Florida compile comprehensive inventories of reuse projects by type of reuse application. These inventories are compiled by the California Water Resources Control Board (CWRCB) in Sacramento and the Florida Department of Environmental Protection (FDEP) in Tallahassee, respectively. The inventories are available for viewing or downloading from each agency’s website. Florida’s 2001 Reuse Inventory shows a total of 461 domestic wastewater treatment facilities with permitted capacities of 0.1 mgd (4.4 l/s) or more that produce reclaimed water. These treatment facilities serve 431 reuse systems and provide 584 mgd (25,600 l/s) of reclaimed water for beneficial purposes. The total reuse capacity associated with these systems is 1,151 mgd (50,400 l/s) (FDEP, 2002). California’s May 2000 Municipal Wastewater Reclamation Survey, estimated a total of 358 mgd (14,800 l/s) treated municipal wastewater was being reused. This represents a 50 percent increase from the survey undertaken by CWRCB in 1987. The wastewater is treated at 234 treatment plants and is being reused at approximately 4,840 sites (CWRCB, 2000). Figures 4-1 and 4-2 show the types of reuse occurring in California and Florida, respectively.


Figure 4-1.

California Water Reuse by Type (Total 358 mgd)

Most states do not have regulations that cover all potential uses of reclaimed water. Arizona, California, Colorado, Florida, Hawaii, Nevada, New Jersey, Oregon, Texas, Utah, and Washington have extensive regulations or guidelines that prescribe requirements for a wide range of end uses of the reclaimed water. Other states have regulations or guidelines that focus upon land treatment of wastewater effluent, emphasizing additional treatment or effluent disposal rather than beneficial reuse, even though the effluent may be used for irrigation of agricultural sites, golf courses, or public access lands. Based on the inventory, current regulations and guidelines may be divided into the following reuse categories:

Source: Adapted from California Environmental Protection Agency

Unrestricted urban reuse – irrigation of areas in which public access is not restricted, such as parks, playgrounds, school yards, and residences; toilet flushing, air conditioning, fire protection, construction, ornamental fountains, and aesthetic impoundments. Restricted urban reuse – irrigation of areas in which public access can be controlled, such as golf courses, cemeteries, and highway medians. Agricultural reuse on food crops – irrigation of food crops which are intended for direct human consumption, often further classified as to whether the food crop is to be processed or consumed raw. Agricultural reuse on non-food crops – irrigation of fodder, fiber, and seed crops, pasture land, commercial nurseries, and sod farms. Unrestricted recreational reuse – an impoundment of water in which no limitations are imposed on bodycontact water recreation activities. Restricted recreational reuse – an impoundment of reclaimed water in which recreation is limited to fishing, boating, and other non-contact recreational activities. ate manmade wetlands, enhance natural wetlands, and sustain or augment stream flows.

Figure 4-2.

Florida Water Reuse by Type (Total 584 mgd)





Source: 2001 Florida Water Reuse Inventory „

Every 5 years, the U.S. Geological Survey (USGS) compiles an estimate of national reclaimed water use that is entered in a national database system and publishes its findings in a national circular, Estimated Use of Water in the United States. The 1995 publication estimated that approximately 983 mgd (43,060 l/s) of the effluent discharged in the U.S. was released for beneficial reuse, an increase of 55 mgd (2,410 l/s) from the 1990 estimate (Perlman et al., 1998). More current estimates were not available from the USGS at the time of this update, but it is anticipated that the 2000 publication will be available at the time these guidelines are published.

„ Environmental reuse – reclaimed water used to cre-

„ Industrial reuse – reclaimed water used in industrial

facilities primarily for cooling system make-up water, boiler-feed water, process water, and general washdown.


„ Groundwater recharge – using either infiltration

basins, percolation ponds, or injection wells to recharge aquifers.


Indirect potable reuse – the intentional discharge of highly treated reclaimed water into surface waters or groundwater that are or will be used as a source of potable water.

Table 4-2 shows the number of states with regulations or guidelines for each type of reuse. The category of unrestricted urban reuse has been subdivided to indicate the number of states that have regulations pertaining to urban reuse not involving irrigation. States with regulations or guidelines pertaining to the use of reclaimed water for the following unrestricted urban reuse categories are:

Table 4-1 (on the following page) provides an overview of the current water reuse regulations and guidelines by state and by reuse category. The table identifies those states that have regulations, those with guidelines, and those states that currently do not have either. Regulations refer to actual rules that have been enacted and are enforceable by government agencies. Guidelines, on the other hand, are not enforceable but can be used in the development of a reuse program. The majority of current state regulations and guidelines pertain to the use of reclaimed water for urban and agricultural irrigation. At the time of the survey, the only states that had specific regulations or guidelines regarding the use of reclaimed water for purposes other than irrigation were Arizona, California, Colorado, Florida, Hawaii, Massachusetts, Nevada, New Jersey, North Carolina, Oregon, South Dakota, Texas, Utah, and Washington. The 1995 Substitute Senate Bill 5605, “Reclaimed Water Act,” passed in the State of Washington, states that reclaimed water is no longer considered wastewater (Van Riper et al., 1998). Table 4-2.

Toilet Flushing – Arizona, California, Florida, Hawaii, Massachusetts, New Jersey, North Carolina, Texas, Utah, and Washington Fire Protection – Arizona, California, Florida, Hawaii, New Jersey, North Carolina, Texas, Utah, and Washington Hawaii, New Jersey, North Carolina, Oregon, Utah, and Washington


„ Construction Purposes – Arizona, California, Florida,


Landscape or Aesthetic Impoundments – Arizona, California, Colorado, Florida, Hawaii, Nevada, New Jersey, North Carolina, Oregon, Texas, and Washington Street Cleaning – Arizona, California, Florida, Hawaii, North Carolina, and Washington


Number of States with Regulations or Guidelines for Each Type of Reuse Application

Type of Reuse Unrestricted Urban Irrigation Toilet Flushing Fire Protection Construction Landscape Impoundment Street Cleaning Restricted Urban Agricultural (Food Crops) Agricultural (Non-food Crops) Unrestricted Recreational Restricted Recreational Environmental (Wetlands) Industrial Groundwater Recharge (Nonpotable Aquifer) Indirect Potable Reuse

Number of States 28 28 10 9 9 11 6 34 21 40 7 9 3 9 5 5


Table 4-1.

Summary of State Reuse Regulations and Guidelines
Unrestricted Urban Reuse

Change from 1992 Guidelines for (2) Water Reuse

Agricultural Reuse Food Crops

Agricultural Reuse Non-Food Crops

No Regulations or (1) Guidelines

Restricted Urban Reuse

Industrial Reuse


Alabama Alaska Arizona Arkansas (3) California Colorado Connecticut Delaware Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming

z z z z z z (4) z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z


z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z

z z z z z z z z z z z z z z z

z z z z z z z z

z z z z z

z z

z z

z z


z z z

z z z


z z z z z z z z

z z z z z z z z z z z

z z z z

z z z z z z z z z z z z z z z z z z z z z z


z z


z z




z z z z z

z z z z z

z z z z z z z

z z



z z z








(1) (2)


Specific regulations on reuse not adopted: however, reclamation may be approved on a case-by-case basis N - no change NR - no guidelines or regulations to regulations U - updated guidelines or regulations NG - no guidelines or regulations to guidelines GR - guidelines to regulations RG - regulations to guidelines Has regulations for landscape irrigation excluding residential irrigation; guidelines cover all other uses


Indirect Potable Reuse z z z z

Environmental Reuse

Groundwater Recharge

Unrestricted Recreational Reuse

Restricted Recreational Reuse



It is important to understand that because a state does not have specific guidelines or regulations for a particular type of reuse as defined in this chapter, it does not mean that the state does not allow that type of reuse under other uses. Also, some states allow consideration of reuse options that are not addressed within their existing guidelines or regulations. For example, Florida’s rules governing water reuse enable the state to permit other uses, if the applicant demonstrates that public health will be protected.

limit on turbidity is usually specified to monitor the performance of the treatment facility. This discussion on reclaimed water quality and treatment requirements is based on the regulations from the following states: Arizona, California, Florida, Hawaii, Nevada, Texas, and Washington. These regulations were chosen because these states provide a collective wisdom of successful reuse programs and long-term experience. Unrestricted Urban Reuse


Reclaimed Water Quality and Treatment Requirements

Requirements for water quality and treatment receive the most attention in state reuse regulations. States that have water reuse regulations or guidelines have set standards for reclaimed water quality and/or specified minimum treatment requirements. Generally, where unrestricted public exposure is likely in the reuse application, wastewater must be treated to a high degree prior to its application. Where exposure is not likely, however, a lower level of treatment is usually accepted. The most common parameters for which water quality limits are imposed are biochemical oxygen demand (BOD), total suspended solids (TSS), and total or fecal coliform counts. Total and fecal coliform counts are generally used as indicators to determine the degree of disinfection. A Table 4-3. Unrestricted Urban Reuse
Arizona Secondary treatment, filtration, and disinfection NS NS 2 NTU (Avg) 5 NTU (Max) Fe cal None detectable (Avg) 23/100 ml (Max)

Unrestricted urban reuse involves the use of reclaimed water where public exposure is likely in the reuse application, thereby necessitating a high degree of treatment. In general, all states that specify a treatment process require a minimum of secondary treatment and treatment with disinfection prior to unrestricted urban reuse. However, the majority of states require additional levels of treatment that may include oxidation, coagulation, and filtration. Texas does not specify the type of treatment processes required and only sets limits on the reclaimed water quality. Table 4-3 shows the reclaimed water quality and treatment requirements for unrestricted urban reuse. Where specified, limits on BOD range from 5 mg/l to 30 mg/l. Texas requires that BOD not exceed 5 mg/l (monthly

California Oxidized, coagulated, filtered, and disinfected NS NS 2 NTU (Avg) 5 NTU (Max) Total 2.2/100 ml (Avg) 23/100 ml (Max in 30 days)

Florida Secondary treatment, filtration, and high- level disinfection 20 mg/l CBOD5 5.0 mg/l NS Fe cal 75% of samples below detection 25/100 ml (Max)

Haw aii Oxidized, filtered, and disinfected

Ne vada Secondary treatment and disinfection

Te xas

Was hington Oxidized, coagulated, filtered, and disinfected 30 mg/l 30 mg/l 2 NTU (Avg) 5 NTU (Max)

Treatm ent



BOD5 TSS Turbidity

NS NS 2 NTU (Max) Fe cal 2.2/100 ml (Avg) 23/100 ml (Max in 30 days)

30 mg/l NS NS Fe cal 2.2/100 ml (Avg)

5 mg/l NS 3 NTU Fe cal 20/100 ml (Avg)

Total 2.2/100 ml (Avg)


23/100 ml (Max)

75/100 ml (Max)

23/100 ml (Max)

NS - Not specified by state regulations 153

average) except when reclaimed water is used for landscape impoundments. In that case, BOD is limited to 10 mg/l. Nevada, on the other hand, requires that BOD not exceed 30 mg/l prior to unrestricted urban reuse. Limits on TSS vary from 5 mg/l to 30 mg/l. Florida requires a TSS limit of 5.0 mg/l prior to disinfection and Washington requires that TSS not exceed 30 mg/l. Average fecal and total coliform limits range from nondetectable to 20/100 ml. Higher single sample fecal and total coliform limits are allowed in several state regulations. Florida requires that 75 percent of the fecal coliform samples taken over a 30-day period be below detectable levels, with no single sample in excess of 25/100 ml, while Texas requires that no single fecal coliform count exceed 75/100 ml. In general and where specified, limits on turbidity range from 2 to 5 NTU. Most of the states require an average turbidity limit of 2 NTU and a not-to-exceed limit of 5 NTU, although Hawaii’s guidelines identify a not-to-exceed limit of 2 NTU. Florida requires continuous on-line monitoring of turbidity as an indicator that the TSS limit of 5.0 mg/l is being met. No limit is specified but turbidity setpoints used in Florida generally range from 2 to 2.5 NTU. California specifies different turbidity requirements for wastewater that has been coagulated and passed through natural and undisturbed soils or a bed of filter media, as well as wastewater passed through membranes. For the first, turbidity is not to exceed 5 NTU for Table 4-4. Restricted Urban Reuse
Arizona California Flor ida Secondary treatment, filtration, and high-level disinfection 20 mg/l CBOD 5 5 mg/l NS Fe cal 75% of samples below detection 25/100 ml (Max)

more than 5 percent of the time within a 24-hour period and not to exceed 10 NTU at any time. For the latter, turbidity is not to exceed 0.2 NTU more than 5 percent of the time within a 24-hour period and not to exceed 0.5 NTU at any time. At this time, no states have set limits on certain pathogenic organisms for unrestricted urban reuse. However, Florida does require monitoring of Giardia and Cryptosporidium with sampling frequency based on treatment plant capacity. For systems less than 1 mgd (44 l/s), sampling is required one time during each 5-year period. For systems equal to or greater than 1 mgd (44 l/ s), sampling is required one time during each 2-year period. Samples are to be taken following the disinfection process. Restricted Urban Reuse

Restricted urban reuse involves the use of reclaimed water where public exposure to the reclaimed water is controlled; therefore, treatment requirements may not be as strict as for unrestricted urban reuse. Six states, which regulate both unrestricted and restricted urban reuse, adjusted requirements downward for the restricted category. Florida imposes the same requirements on both unrestricted and restricted urban access reuse. Table 4-4 shows the reclaimed water quality and treatment requirements for restricted urban reuse.

Haw aii

Ne vada Secondary treatment and disinfection

Te xas

Was hington

Tr e atm e nt

Secondary – Secondary treatment and 23, oxidized, disinfection and disinfected

O x idiz ed and disinfected



O x idiz ed and disinfected

BOD5 TSS Turbidity

NS NS NS Fe cal 200/100 ml (Avg) 800/100 ml (Max)

NS NS NS Total 23/100 ml (Avg) 240/100 ml (Max in 30 days)

NS NS 2 NTU (Max) Fe cal 23/100 ml (Avg) 200/100 ml (Max)

30 mg/l NS NS Fe cal 23/100 ml (Avg) 240/100 ml (Max)

20 mg/l NS 3 NTU Fe cal 200/100 ml (Avg) 800/100 ml (Max)

30 mg/l 30 mg/l 2 NTU (Avg) 5 NTU (Max) Total 23/100 ml (Avg) 240/100 ml (Max)

Colifor m


NS - Not specified by state regulations 154

Table 4-5.

Agricultural Reuse - Food Crops
A r iz o n a Sec ondary treatm ent, filtration, and dis infec tion NS NS 2 N T U (Av g) 5 N T U (M ax ) Fe cal N one detec table (Av g) 23/100 m l (M ax ) C alifo r n ia O x idiz ed, c oagulated, filtered, and dis infec ted NS NS 2 N T U (Av g) 5 N T U (M ax ) T o tal 2.2/100 m l (Av g) 23/100 m l (M ax in 30 day s ) Fe cal 75% of s am ples below detec tion 25/100 m l (M ax ) Fe cal 2.2/100 m l (Av g) 23/100 m l (M ax in 30 day s ) Fe cal 200/100 m l (Av g) 400/100 m l (M ax ) Fe cal 20/100 m l (Av g) 75/100 m l (M ax ) Flo r id a Sec ondary treatm ent, filtration, and high-lev el dis infec tion 20 m g/l C BO D 5 5 m g/l NS Haw aii O x idiz ed, filtered, and dis infec ted Ne vad a Sec ondary treatm ent and dis infec tion T e xas W as h in g to n O x idiz ed, c oagulated, filtered, and dis infec ted 30 m g/l 30 m g/l 2 N T U (Av g) 5 N T U (M ax ) T o tal 2.2/100 m l (Av g) 23/100 m l (M ax )

T r e atm e n t

N S (1)

BOD5 T SS T u r b id ity

NS NS 2 N T U (M ax )

30 m g/l NS NS

5 m g/l NS 3 NTU

C o lifo r m


NS - Not specified by state regulations

In general, the states require a minimum of secondary or biological treatment followed by disinfection prior to restricted urban reuse. Florida requires additional levels of treatment with filtration and possibly coagulation prior to restricted urban reuse. As in unrestricted urban reuse, Texas does not specify the type of treatment processes required and only sets limits on the reclaimed water quality. Where specified, limits on average BOD range from 20 mg/l to 30 mg/l. Florida and Texas require that BOD not exceed 20 mg/l, while Nevada and Washington require that BOD not exceed 30 mg/l prior to restricted urban reuse. Limits on TSS vary from 5 mg/l to 30 mg/l. Florida requires that TSS not exceed 5.0 mg/l, while Washington requires that TSS not exceed 30 mg/l. As in unrestricted urban reuse, for those states that do not specify limitations on BOD or TSS, a particular level of treatment is usually specified. Average fecal coliform limits range from non-detectable to 200/100 ml, with some states allowing higher single sample fecal coliform limits. As for unrestricted urban reuse, Florida requires that 75 percent of the fecal coliform samples taken over a 30-day period be below detectable levels, with no single sample in excess of 25/100 ml. Arizona and Texas require that no single fecal coliform count exceed 800/100 ml.

Washington is the only state that sets a limit on turbidity for restricted urban reuse with an average turbidity limit of 2 NTU and a not-to-exceed at any time limit of 5 NTU. At this time, no states have set limits on certain pathogenic organisms for restricted urban reuse. However, Florida does require monitoring of Giardia and Cryptosporidium with sampling frequency as noted in Section Agricultural Reuse - Food Crops

The use of reclaimed water for irrigation of food crops is prohibited in some states, while others allow irrigation of food crops with reclaimed water only if the crop is to be processed and not eaten raw. Nevada allows only surface irrigation of fruit or nut bearing trees. Treatment requirements range from secondary treatment in Nevada for irrigation of processed food crops, to oxidation, coagulation, filtration, and disinfection in Arizona, California, Florida, Hawaii, and Washington. Table 4-5 shows the reclaimed water quality and treatment requirements for irrigation of food crops. Most states require a high level of treatment when reclaimed water is used for edible crops, especially those that are to be consumed raw. As in other reuse applications, however, existing regulations on treatment and


water quality requirements vary from state to state and depend largely on the type of irrigation employed and the type of food crop being irrigated. For example, for foods consumed raw, Washington requires that the reclaimed water be oxidized and disinfected when surface irrigation is used, with the mean total coliform count not to exceed 2.2/100 ml. When spray irrigation is utilized, Washington requires that the reclaimed water be oxidized, coagulated, filtered, and disinfected, with the mean total coliform count not to exceed 2.2/100 ml. For processed foods, Washington requires only oxidation and disinfection regardless of the type of irrigation, with a 7-day mean total coliform count of 240/100 ml. Where specified, limits on BOD range from 5 mg/l to 30 mg/l. Texas requires a monthly average BOD limit of 5 mg/l when reclaimed water will be used to irrigate unprocessed food crops. In Texas, spray irrigation is not permitted on foods that may be consumed raw, and only irrigation types that avoid reclaimed water contact with edible portions of food crops are acceptable. Florida requires that the annual average CBOD not exceed 20 mg/l after secondary treatment with filtration and highlevel disinfection, while Texas requires that the BOD not exceed 30 mg/l (monthly average) when the reclaimed water is treated using a pond system and is to be used to irrigate food crops undergoing processing. Limits on TSS vary from 5 mg/l to 30 mg/l. Florida requires that TSS not exceed 5.0 mg/l in any one sample prior to disinfection, while Washington requires that the TSS not exceed 30 mg/l (monthly average). In Florida, direct contact (spray) irrigation of edible crops that will not be peeled, skinned, cooked, or thermally-processed before consumption is not allowed except for tobacco and citrus. Indirect contact methods (ridge and furrow, drip, subsurface application system) can be used on any type of edible crop. California allows for direct contact irrigation with the edible portion of the crop. Average fecal and total coliform limits range from nondetectable to 200/100 ml. Arizona requires no detectable limit for fecal coliform when reclaimed water will be used for spray irrigation of food crops. Florida requires that 75 percent of the fecal coliform samples taken over a 30-day period be below detectable levels, with no single sample in excess of 25/100 ml. Conversely, Nevada requires a maximum fecal coliform count of less than 400/100 ml with only surface irrigation of fruit and nut bearing trees. Again, some states allow higher single sample coliform counts. Limits on turbidity range from 2 to 10 NTU. For example, California requires that turbidity not exceed 2 NTU within a 24-hour period, not exceed 5 NTU more than 5 per-

cent of the time, and not exceed a maximum of 10 NTU at any time for reclaimed water that has been coagulated and passed through natural undisturbed soils or a bed of filter media and is irrigated on food crops to be consumed raw. California requires that the turbidity not exceed 0.2 NTU more than 5 percent of the time and not exceed a maximum of 0.5 NTU at any time for reclaimed water that has been passed through a membrane and is irrigated on food crops to be consumed raw. Hawaii requires that the detectable turbidity not exceed 5 NTU for more than 15 minutes and never exceed 10 NTU prior to filtration for reclaimed water used for spray irrigation of food crops. At this time, no states have set limits on certain pathogenic organisms for agricultural reuse on food crops. Florida does require monitoring of Giardia and Cryptosporidium with sampling frequency as noted in Section Agricultural Reuse – Non-food Crops

The use of reclaimed water for agricultural irrigation of non-food crops presents a reduced opportunity of human exposure to the water, resulting in less stringent treatment and water quality requirements than other forms of reuse. In the majority of the states, secondary treatment followed by disinfection is required, although Hawaii also requires filtration. Table 4-6 shows the reclaimed water quality and treatment requirements for irrigation of non-food crops. Where specified, limits on BOD range from 5 mg/l to 30 mg/l. Texas requires that BOD not exceed 5 mg/l (monthly average) except when reclaimed water is used for landscape impoundments, in which case BOD is limited to 10 mg/l. Florida requires that the annual average CBOD not exceed 20 mg/l after secondary treatment and basic disinfection. Washington and Nevada require that BOD not exceed 30 mg/l as a monthly average. Limits on TSS vary from 20 mg/l to 30 mg/l. Florida requires that the annual average TSS not exceed 20 mg/l except when a subsurface application is used, in which case the single sample TSS limit is 10 mg/l. Washington requires a monthly mean of 30 mg/l TSS. Average fecal and total coliform limits range from 2.2/100 ml for Hawaii to 200/100 ml for Arizona and Florida. There are several states that do not require disinfection if certain buffer requirements are met. For example, Nevada requires no disinfection with a minimum buffer zone of 800 feet for spray irrigation of non-food crops. Some states allow higher single sample coliform counts. For example, Arizona requires that no single fecal coliform count ex-


Table 4-6.

Agricultural Reuse - Non-Food Crops
A r iz o n a C alifo r n ia Flo r id a Sec ondary treatm ent, bas ic dis infec tion 20 m g/l C BO D 5 20 m g/l Haw aii O x idiz ed, filtered, and dis infec ted NS NS Ne vad a Sec ondary treatm ent and dis infec tion 30 m g/l NS T e xas W as h in g to n O x id iz e d and dis infec ted

T r e atm e n t

Sec ondary Sec ondary -23, treatm ent and O x idiz ed, and dis infec tion dis infec ted NS NS NS NS


(1 )


5 m g/l NS

30 m g/l 30 m g/l 2 N T U (Av g)

T u r b id ity




2 N T U (M ax )


3 NTU 5 N T U (M ax )

Fe cal 200/100 m l (Av g) 800/100 m l (M ax )

T o tal 23/100 m l (Av g) 240/100 m l (M ax in 30 day s )

Fe cal 200/100 m l (Av g) 800/100 m l (M ax )

Fe cal 2.2/100 m l (Av g) 23/100 m l (M ax )

Fe cal 200/100 m l (Av g) 400/100 m l (M ax )

Fe cal 20/100 m l (Av g) 75/100 m l (M ax )

T o tal 23/100 m l (Av g) 240/100 m l (M ax )

C o lifo r m

NS - Not specified by state regulations

ceed 4,000/100 ml when reclaimed water will be used for irrigation of pasture for non-dairy animals. At this time, Hawaii, Texas, and Washington require limits on turbidity for reclaimed water used for agricultural reuse on non-food crops. Washington requires that the turbidity not exceed 2 NTU as an average and not exceed 5 NTU at any time. Texas requires a turbidity limit of 3 NTU for reclaimed water that will be used for irrigation of pastures for milking animals. Hawaii, on the other hand, requires the detectable turbidity not exceed 5 NTU for more than 15 minutes and never exceed 10 NTU prior to filtration for reclaimed water used for spray irrigation of pastures for milking and other animals. At this time, no states have set limits on certain pathogenic organisms for agricultural reuse on non-food crops. Unrestricted Recreational Reuse

Nevada requires secondary treatment with disinfection, while California requires oxidation, coagulation, clarification, filtration, and disinfection. Where specified, limits on BOD range from 5 mg/l to 30 mg/l. Texas requires that BOD not exceed 5 mg/l as a monthly average, while Washington requires that BOD not exceed 30 mg/l prior to unrestricted recreational reuse. Washington is the only state to set a limit on TSS and requires 30 mg/l or less as a monthly average. All states, except Texas, require that the median total coliform count not exceed 2.2/100 ml, with no single sample to exceed 23/100 ml. Texas requires that the median fecal coliform count not exceed 20/100 ml, with no single sample to exceed 75/ 100 ml. Limits on turbidity generally range from 2 NTU to 5 NTU. Most of the states require an average turbidity limit of 2 NTU and a not-to-exceed limit of 5 NTU. California specifies different turbidity requirements for wastewater that has been coagulated and passed through natural and undisturbed soils or a bed of filter media as well as wastewater passed through membranes. For the first, turbidity is not to exceed 5 NTU for more than 5 percent of the time within a 24-hour period and not to exceed 10 NTU at any time. For the latter, turbidity is not to exceed 0.2 NTU more than 5 percent of the time within a 24-hour period and not to exceed 0.5 NTU at any time. Texas requires a turbidity limit of 3 NTU, and Nevada does not specify a limit on turbidity.

As with unrestricted urban reuse, unrestricted recreational reuse involves the use of reclaimed water where public exposure is likely, thereby necessitating a high degree of treatment. Only 4 of the 7 states (California, Nevada, Texas, and Washington) have regulations or guidelines pertaining to unrestricted recreational reuse. Table 4-7 shows the reclaimed water quality and treatment requirements for unrestricted recreational reuse.


Table 4-7.

Unrestricted Recreational Reuse
A r iz o n a C alifo r n ia O x idiz e d, c oag ulate d, c la rified , filter ed , an d dis in fec ted NS
(2 )

Flo r id a

Haw aii

Ne vad a Se c on dar y tr eatm en t an d dis infe c tion 30 m g/l NS NS Fe c al 2.2 /10 0 m l (Av g ) 23/100 m l (Max )

T e x as

W as h in g t o n O x idiz e d, c oag ulate d, filter ed , an d dis in fec ted 3 0 m g /l 3 0 m g/l 2 N T U (Av g ) 5 N T U (Max ) Fe cal 2 .2/1 00 m l ( Av g) 2 3 /1 0 0 m l (M ax )

T r e a tm e n t


(1 )




BOD 5 T SS T u r b id ity




5 m g/l NS 3 NTU Fe cal 2 0 /1 0 0 m l ( A v g ) 75 /10 0 m l ( M ax )

NS 2 N T U (Av g ) 5 N T U (Max ) T o tal

C o lif o r m


2 .2/1 00 m l ( Av g) 23/1 00 m l ( M a x in 3 0 da y s )



(1) NR - Not regulated by the state (2) NS - Not specified by state regulations

Table 4-8.

Restricted Recreational Reuse
Ar iz o n a C alifo r n ia Sec ondary -23, ox idiz ed, and dis infec ted NS NS NS T o tal 2.2/100 ml (Av g) 23/100 ml (Max in 30 day s ) Flo r id a
(1 )

Haw aii O x idiz ed, filtered, and dis infec ted NS NS 2 NT U (Max ) Fe cal 2.2/100 ml (Av g) 23/100 ml (Max )

Ne vad a Sec ondary treatment and dis infec tion 30 mg/l NS NS Fe cal 200/100 ml (Av g) 23/100 ml (Max )

T e xas NS

Was h in g to n O x idiz ed and dis infec ted 30 mg/l 30 mg/l 2 NT U (Av g) 5 N T U (Max )

Tr e atm e nt BOD5 T SS T u r b id ity

Sec ondary treatment, filtration, and dis infec tion NS
(2 )



20 mg/l NS NS Fe cal 200/100 ml (Av g) 800/100 ml (Max )

NS 2 NT U (Av g) 5 NT U (Max ) Fe cal None detec table (Av g) 23/100 ml (Max )

T o tal 2.2/100 ml (Av g)

Colifor m


23/100 ml (Max )

(1) NR - Not regulated by the state (2) NS - Not specified by state regulations

At this time, no states have set limits on certain pathogenic organisms for unrestricted recreational reuse. Restricted Recreational Reuse

State regulations and guidelines regarding treatment and water quality requirements for restricted recreational reuse are generally less stringent than for unrestricted rec-

reational reuse since the public exposure to the reclaimed water is less likely. Six of the 7 states (Arizona, California, Hawaii, Nevada, Texas, and Washington) have regulations pertaining to restricted recreational reuse. With the exception of Arizona and Hawaii, which require filtration, the remaining states require secondary treatment with disinfection. Texas does not specify treatment process requirements. Table 4-8 shows the reclaimed wa-


ter quality and treatment requirements for restricted recreational reuse. Nevada, Texas, and Washington have set limits on BOD ranging from 20 mg/l to 30 mg/l as a monthly average. Only Washington has set limits on TSS of 30 mg/l as a monthly average. Arizona requires no detectable fecal coliform in 4 of the last 7 daily samples and a single sample maximum of 23/100 ml. California, Hawaii, Nevada, and Washington require that the median total coliform count not exceed 2.2/100 ml. Texas, on the other hand, requires that the median fecal coliform count not exceed 200/100 ml and that a single sample not exceed 800/100 ml. Limits on turbidity are specified for Arizona, Hawaii, and Washington. Arizona and Washington require a turbidity of less than 2 NTU as an average and a not-to-exceed maximum of 5 NTU. Hawaii specifies an effluent turbidity requirement of 2 NTU. California, Nevada, and Texas have not specified turbidity requirements for restricted recreational reuse. At this time, no states have set limits on certain pathogenic organisms for restricted recreational reuse. Environmental - Wetlands

pertaining to the use of reclaimed water for creation of artificial wetlands and/or the enhancement of natural wetlands. Table 4-9 shows the reclaimed water quality and treatment requirements for environmental reuse. Florida has comprehensive and complex rules governing the discharge of reclaimed water to wetlands. Treatment and disinfection levels are established for different types of wetlands, different types of uses, and the degree of public access. Most wetland systems in Florida are used for tertiary wastewater treatment; and wetland creation, restoration, and enhancement projects can be considered reuse. Washington also specifies different treatment requirements for different types of wetlands and based on the degree of public access. General compliance requirements of 20 mg/l BOD and TSS, 3 mg/l total Kjeldahl nitrogen (TKN), and 1 mg/l total phosphorus must be met for all categories. Industrial Reuse

Five of the 7 states (California, Florida, Hawaii, Texas, and Washington) have regulations or guidelines pertaining to industrial reuse of reclaimed water. Table 4-10 shows the reclaimed water quality and treatment requirements for industrial reuse. Reclaimed water quality and treatment requirements vary based on the final use of the reclaimed water and exposure potential (see Appendix A, Table A-8 for a sum-

A review of existing reuse regulations shows only 2 of the 7 states (Florida and Washington) have regulations Table 4-9. Environmental Reuse - Wetlands
A r iz o n a T r e atm e n t BOD5 T SS NR

C alif o r n ia NR NR NR

Flo r id a (1 ) Ad v an c ed treatm ent 5 m g/l C BO D 5 5 m g/l

Haw aii NR NR NR

Ne vad a NR NR NR

T e xas NR NR NR

W as h in g to n O x idiz ed , c oagulated, and dis infec ted 20 m g/l 20 m g/l Fe cal


C o lifo r m








2.2/100 m l (Av g) 23/100 m l (M ax )

T o t al A m m o n ia T o t al Ph o s p h o r u s



2 m g/l




N ot to ex c eed c hr onic s tandards for fres hw ater 1 m g/l



1 m g/l




(1) Florida requirements are for discharge of reclaimed water to receiving wetlands (2) NR - Not regulated by the state (3) NS - Not specified by state regulations


Table 4-10.

Industrial Reuse(1)
Ar izona Califor nia O xidiz ed and disinfec ted NS

Flor ida Sec ondary treatment and basic dis infec tion 20 mg/l 20 mg/l NS Fe cal 200/100 ml (Av g) 800/100 ml (Max )

Haw aii O xidiz ed and disinfec ted NS NS NS Fe cal 23/100 ml (Av g) 200/100 ml (Max )

Ne vada

Te xas

Was hington O xidiz ed and dis infec ted NS NS NS Total

Tr e atm e nt





BOD5 TSS Tur bidity



20 mg/l --3 NTU Fe cal

NS NS Total 23/100 ml (Av g) 240/100 ml (Max in 30 days)

Colifor m



200/100 ml 23/100 ml (Av g) (Av g) 800/100 ml (Av g) 240/100 ml (Av g)

(1) All state requirements are minimum values. Additional treatment may be required depending on expected public exposure. Additional regulations for industrial systems are contained in Appendix A. (2) NR - Not regulated by the state (3) NS - Not specified by state regulations

mary of each state’s regulations). For example, California has different requirements for the use of reclaimed water as cooling water, based on whether or not a mist is created. If a mist is created, oxidation, coagulation, filtration, and disinfection are required and total coliform limits of 2.2/100 ml as a weekly median must be met. If a mist is not created, only oxidation and disinfection are required and total coliform limits of 23/100 ml as a weekly median must be met. Groundwater Recharge

fers, that is not their primary intent and experience suggests current practices are protective of raw water supplies. Based on a review of the existing reuse regulations and guidelines, California, Florida, Hawaii, and Washington have regulations or guidelines for reuse with the specific intent of groundwater recharge of aquifers. Table 4-11 shows reclaimed water quality and treatment requirements for groundwater recharge via rapid-rate application systems. For groundwater recharge, California and Hawaii do not specify required treatment processes and determine requirements on a case-by-case basis. The California and Hawaii Departments of Health Services base the evaluation on all relevant aspects of each project including treatment provided, effluent quality and quantity, effluent or application spreading area operation, soil characteristics, hydrogeology, residence time, and distance to withdrawal. Hawaii does require a groundwater monitoring program. Washington has extensive guidelines for the use of reclaimed water for direct groundwater recharge of nonpotable aquifers. It requires Class A reclaimed wa-

Spreading basins, percolation ponds, and infiltration basins have a long history of providing both effluent disposal and groundwater recharge. Most state regulations allow for the use of relatively low quality water (i.e., secondary treatment with basic disinfection) based on the fact that these systems have a proven ability to provide additional treatment. Traditionally, potable water supplies have been protected by requiring a minimum separation between the point of application and any potable supply wells. These groundwater systems are also typically located so that their impacts to potable water withdrawal points are minimized. While such groundwater recharge systems may ultimately augment potable aqui-


Table 4-11.

Groundwater Recharge (1)

Ar iz on a

Califor nia (2)

Flor ida Sec ondary treatment and bas ic dis infec tion NS

Haw aii

Ne vada

Te xas

Was hin gto n O x idiz ed, c oagulated, filtered, and dis infec ted 5 mg/l 5 mg/l 2 NT U (Av g) 5 NT U (Max ) T otal 2.2/100 ml (Av g) 23/100 ml (Max )

T r e atm e n t





BOD5 TSS Tu r bid ity

NR NR NR Cas e-by -c as e bas is

NR NR Cas e-by -c as e bas is NR


10.0 mg/l NS

Co lifo r m





T otal Nitr og e n


12 mg/l




(1) All state requirements are for groundwater recharge via rapid-rate application systems. Additional regulations for recharge of potable aquifers are contained in Section and Appendix A. (2) Groundwater recharge in California and Hawaii is determined on a case-by-case basis (3) NR - Not regulated by the state (4) NS - Not specified by state regulations ter defined as oxidized, coagulated, filtered, and disinfected. Total coliform is not to exceed 2.2/100 ml as a 7-day median and 23/100 ml in any sample. Weekly average BOD and TSS limits are set at 5 mg/l. Turbidity is not to exceed 2 NTU as a monthly average and 5 NTU in any sample. Additionally, groundwater monitoring is required and is based on reclaimed water quality and quantity, site-specific soil and hydrogeologic characteristics, and other considerations. Washington also specifies that reclaimed water withdrawn for nonpotable purposes can be withdrawn at any distance from the point of injection and at any time after direct recharge. Florida requires that TSS not exceed 5.0 mg/l in any sample, be achieved prior to disinfection, and that the total nitrogen in the reclaimed water be less than 12 mg/ l. Florida also requires continuous on-line monitoring of turbidity; however, no limit is specified. Indirect Potable Reuse Indirect potable reuse involves the use of reclaimed water to augment surface water sources that are used or will be used for public water supplies or to recharge groundwater used as a source of domestic water supply. Unplanned indirect potable water reuse is occurring in many river systems today. Many domestic wastewater treatment plants discharge treated effluent to surface waters upstream of intakes for domestic water supply treatment plants. Additionally, many types of beneficial reuse projects inadvertently contribute to groundwater augmentation as an unintended result of the primary activity. For example, irrigation can replenish groundwater sources that will eventually be withdrawn for use as a potable water supply. Indirect potable reuse systems, as defined here, are distinguished from typical groundwater recharge systems and surface water discharges by both intent and proximity to subsequent withdrawal points for potable water use. Indirect potable reuse involves the intentional introduction of reclaimed water into the raw water supply for the purposes of increasing the total volume of water available for potable use. In order to accomplish this objective, the point at which reclaimed water is introduced into the environment must be selected to ensure it will flow to the point of withdrawal. Typically the design of these systems assumes there will be little to no additional treatment in the environment after discharge, and all applicable water quality requirements are met prior to release of the reclaimed water. Based on a review of the existing reuse regulations and guidelines, 4 of the 7 states (California, Florida, Hawaii,


and Washington) have regulations or guidelines pertaining to indirect potable reuse. For groundwater recharge of potable aquifers, most of the states require a pretreatment program, public hearing requirements prior to project approval, and a groundwater monitoring program. Florida and Washington require pilot plant studies to be performed. In general, all the states that specify treatment processes require secondary treatment with filtration and disinfection. Washington is the only state that specifies the wastewater must be treated by reverse osmosis. California and Hawaii do not specify the type of treatment processes required and determine requirements on a case-by-case basis. Most states specify reclaimed water quality limitations for TSS, nitrogen, total organic carbon (TOC), turbidity, and total coliform. Florida requires that TSS not exceed 5.0 mg/l in any sample and be achieved prior to disinfection. Florida and Washington require the total nitrogen in the reclaimed water to be less than 10 mg/l. Washington has a limit of 1 mg/l for TOC, while Florida’s limit is set at 3 mg/l as a monthly average. Florida also requires an average limit of 0.2 mg/l for total organic halides (TOX). Turbidity limits vary greatly where specified. For example, Washington specifies a limit of 0.1 NTU as a monthly average and 0.5 NTU as a maximum at any time. Florida requires continuous on-line monitoring of turbidity; however, no limit is specified. Fecal coliform limits also vary greatly from state to state. Washington requires a limit of 1/100 ml for total coliform as a weekly median and a not to exceed limit of 5/100 ml in any one sample for direct injection into a potable aquifer. The states that specify reclaimed water quality limitations require the reclaimed water to meet drinking water standards. Most states specify a minimum time the reclaimed water must be retained underground prior to being withdrawn as a source of drinking water. Washington requires that reclaimed water be retained underground for a minimum of 12 months prior to being withdrawn as a drinking water supply. Several states also specify minimum separation distances between a point of recharge and the point of withdrawal as a source of drinking water. Florida requires a 500-foot (150-meter) separation distance between the zone of discharge and potable water supply well. Washington requires the minimum horizontal separation distance between the point of direct recharge and point of withdrawal as a source of drinking water supply to be 2,000 feet (610 meters). Table 4-12 shows the reclaimed water quality and treatment requirements for indirect potable reuse. Florida includes discharges to Class I surface waters (public water supplies) as indirect potable reuse. Discharges less than 24 hours travel time upstream from

Class I waters are also considered as indirect potable reuse. Surface water discharges located more than 24 hours travel time to Class I waters are not considered indirect potable reuse. For discharge to Class I surface waters or water contiguous to or tributary to Class I waters (defined as a discharge located less than or equal to 4 hours travel time from the point of discharge to arrival at the boundary of the Class I water), secondary treatment with filtration, high-level disinfection, and any additional treatment required to meet TOC and TOX limits is required. The reclaimed water must meet primary and secondary drinking water standards, except for asbestos, prior to discharge. TSS must not exceed 5.0 mg/l in any sample prior to disinfection and total nitrogen cannot exceed 10 mg/l as an annual average. The reclaimed water must also meet TOC limitations of 3 mg/l as a monthly average and 5 mg/l in any single sample. Outfalls for surface water discharges are not to be located within 500 feet (150 meters) of existing or approved potable water intakes within Class I surface waters.


Reclaimed Water Monitoring Requirements

Reclaimed water monitoring requirements vary greatly from state to state and again depend on the type of reuse. For unrestricted urban reuse, Oregon requires sampling for coliform daily, while for agricultural reuse of non-food crops, sampling for total coliform is only required once a week. Oregon also requires hourly monitoring of turbidity when a limit on turbidity is specified. For unrestricted and restricted urban reuse, as well as agricultural reuse on food crops, Florida requires the continuous on-line monitoring of turbidity and chlorine residual. Even though no limits on turbidity are specified in Florida, continuous monitoring serves as an online surrogate for suspended solids. In addition, Florida requires that the TSS limit be achieved prior to disinfection and has a minimum schedule for sampling and testing flow, pH, chlorine residual, dissolved oxygen, TSS, CBOD, nutrients, and fecal coliform based on system capacity. Florida also requires an annual analysis of primary and secondary drinking water standards for reclaimed water used in irrigation for facilities greater than 100,000 gpd (4.4 l/s). Monitoring for Giardia and Cryptosporidium must also be performed with frequency dependent on system capacity. Other states determine monitoring requirements on a case-by-case basis depending on the type of reuse.


Treatment Facility Reliability

Some states have adopted facility reliability regulations or guidelines in place of, or in addition to, water quality


Table 4-12.

Indirect Potable Reuse (1)
A r iz o n a C alif o r n ia (2 ) Flo r id a A dv a nc ed tr ea tm e nt, filtr a tio n, an d h ig h- lev e l d is infe c tio n 20 m g /l 5.0 m g /l NS
(4 )

Ha w aii

Ne va d a

T e xas

W as h in g t o n O x id iz e d , c o ag ula te d, filte r e d, r e v e r s e - o s m o s is tr ea te d, a nd d is in fec te d 5 m g /l 5 m g /l 0.1 N T U ( A v g ) 0.5 N T U ( M ax ) T o tal

T r e atm e n t


(3 )



BOD 5 T SS T u r b id it y




T o tal C o lif o r m NR C a s e- by - c as e ba s is A ll s a m p le s le s s th a n de te c tion 10 m g /l 3 m g /l ( A v g ) 5 m g /l ( M ax ) C om p lia nc e w ith m o s t pr im ar y an d s ec on d ar y C as e-by c a s e b a s is NR NR

1/1 0 0 m l ( A v g ) 5/1 0 0 m l ( M ax )

T o t al Nit r o g e n T OC P r im ar y an d S e co n d a r y Stan d ar d s




1 0 m g/l




1 .0 m g/l




C o m p lia n c e w ith m os t pr im ar y a nd s e c o nd a r y

(1) Florida requirements are for the planned use of reclaimed water to augment surface water sources that will be used as a source of domestic water supply (2) Indirect potable reuse in California and Hawaii is determined on a case-by-case basis (3) NR - Not regulated by the state (4) NS - Not specified by state regulations

requirements. Generally, requirements consist of alarms warning of power failure or failure of essential unit processes, automatic standby power sources, emergency storage, and the provision that each treatment process be equipped with multiple units or a back-up unit. Articles 8, 9, and 10 of California’s Title 22 regulations provide design and operational considerations covering alarms, power supply, emergency storage and disposal, treatment processes, and chemical supply, storage, and feed facilities. For treatment processes, a variety of reliability features are acceptable in California. For example, for all biological treatment processes, one of the following is required:
„ Alarm (failure and power loss) and multiple units ca-


Alarm (failure and power loss) and short-term (24hour) storage or disposal provisions and standby replacement equipment storage or disposal provisions

„ Alarm (failure and power loss) and long-term (20-day)

pable of producing biologically oxidized wastewater with one unit not in operation

Florida requires Class I reliability of treatment facilities when reclaimed water is used for irrigation of food crops and for restricted and unrestricted urban reuse. Class I reliability requires multiple treatment units or back-up units and a secondary power source. In addition, a minimum of 1 day of reject water storage is required to store reclaimed water of unacceptable quality for additional treatment. Florida also requires staffing at the water reclamation facility 24 hours/day, 7 days/week or 6 hours/day, 7 days/week. The minimum staffing requirement may be reduced to 6 hours/day, 7 days/week if reclaimed water


is delivered to the reuse system only during periods when a qualified operator is present, or if additional reliability features are provided. Florida has also established minimum system sizes for treatment facilities to aid in assuring the continuous production of high-quality reclaimed water. Minimum system size for unrestricted and restricted urban reuse and for use on edible crops is 0.1 mgd (4.4 l/s). A minimum system size is not required if reclaimed water will be used only for toilet flushing and fire protection uses. Other states that have regulations or guidelines regarding treatment facility reliability include Georgia, Hawaii, Indiana, Massachusetts, North Carolina, Oregon, Utah, Washington, and Wyoming. Washington’s guidelines pertaining to treatment facility reliability are similar to California’s regulations. Georgia, Massachusetts, North Carolina, Oregon, and Wyoming require that multiple treatment units be provided for all essential treatment processes and a secondary or back-up power source be supplied.


Reclaimed Water Storage

Current regulations and guidelines regarding storage requirements are primarily based upon the need to limit or prevent surface water discharge and are not related to storage required to meet diurnal or seasonal variations in supply and demand. Storage requirements vary from state to state and are generally dependent upon geographic location and site conditions. For example, Florida requires a minimum storage volume equal to 3 days of the average design flow, while South Dakota requires a minimum storage volume of 210 days of the average design flow. The large difference in time is primarily due to the high number of non-irrigation days due to freezing temperatures in the northern states. In addition to the minimum storage requirement, Florida also requires that a water balance be performed based on a 1-in-10 year rainfall recurrence interval and a minimum of 20 years of climatic data to determine if additional storage is required beyond the minimum requirement of 3 days. Most states that specify storage requirements do not differentiate between operational and seasonal storage, with the exception of Delaware, Georgia, and Ohio, which require that both operational and wet weather storage be considered. The majority of states that have storage requirements in their regulations or guidelines require that a water balance be performed on the reuse system, taking into account all inputs and outputs of water to the system based on a specified rainfall recurrence interval.

Presently, Florida is the only state with regulations or guidelines for aquifer storage and recovery (ASR) of reclaimed water. ASR systems using reclaimed water are required to meet the technical and permitting requirements of Florida’s Department of Environmental Protection underground injection control program and obtain an underground injection control construction and operation permit in addition to the domestic wastewater permit. Water recovered from the ASR system must meet the performance standards for fecal coliform as specified for high-level disinfection. Specifically, the fecal coliform limits require 75 percent of samples to be below detection limits, and any single sample is not to exceed 25/100 ml before use in a reuse system. Preapplication treatment and disinfection requirements vary depending on the class of groundwater receiving injected reclaimed water, but may be as stringent as to require that reclaimed water meet primary and secondary drinking water standards and TOC and TOX limits prior to injection. Monitoring of the reclaimed water prior to injection and after recovery from the ASR system is required. In addition, a groundwater monitoring plan must be implemented before placing the ASR system into operation. The monitoring plan must be designed to verify compliance with the groundwater standards and to monitor the performance of the ASR system. As part of the monitoring plan, a measure of inorganics concentration (such as chlorides or total dissolved solids) and specific conductance of the water being injected, the groundwater, and the recovered water are required to be monitored. In some cases, an extended zone of discharge for the secondary drinking water standards and for sodium can be approved. Injection wells and recovery wells used for ASR are to be located at least 500 feet from any potable water supply well. For potable water supply wells that are not public water supply wells, a smaller setback distance may be approved if it can be demonstrated that confinement exists such that the system will not adversely affect the quantity or quality of the water withdrawn from the potable water supply well. If the ASR well is located in the same aquifer as a public supply well, the permitting agencies may require a detailed analysis of the potential for reclaimed water entry into the public supply well.


Application Rates

When regulations specify application or hydraulic loading rates, the regulations generally pertain to land application systems that are used primarily for additional wastewater treatment for disposal rather than reuse. When systems are developed chiefly for the purpose of land treatment and/or disposal, the objective is often to dispose of as much effluent on as little land as possible;


thus, application rates are often far greater than irrigation demands and limits are set for the maximum hydraulic loading. On the other hand, when the reclaimed water is managed as a valuable resource, the objective is to apply the water according to irrigation needs rather than maximum hydraulic loading, and application limits are rarely specified. Many states do not have any specific requirements regarding reclaimed water irrigation application rates, as these are generally based on site conditions; however, most states emphasizing beneficial reuse recommend a maximum hydraulic loading rate of no more than 2 inches per week (5.1 cm per week). Delaware’s regulations require that the maximum design wastewater loading be limited to 2.5 inches per week (6.4 cm per week). Florida recommends a maximum annual average of 2 inches per week (5.1 cm per week). Those states emphasizing land treatment or disposal may recommend a hydraulic loading rate of up to 4 inches per week (10.2 cm per week). In addition to hydraulic loading rates, some states also have limits on nitrogen loading. For example, Alabama, Arkansas, and Tennessee all require that the effluent from the reuse system have a nitrate-nitrogen concentration of 10 mg/l or less, while Missouri and Nebraska both require that the nitrogen loading not exceed the nitrogen uptake of the crop.


Setback Distances for Irrigation

Many states have established setback distances or buffer zones between reuse irrigation sites and various facilities such as potable water supply wells, property lines, residential areas, and roadways. Setback distances vary depending on the quality of reclaimed water and the method of application. For example, Nevada requires a 400- to 800-foot (120- to 240-meter) buffer, depending on disinfection level, for a spray irrigation system, but when surface irrigation is used as the application method, no buffer is required. For restricted and unrestricted urban reuse and irrigation of food crops, Florida requires a 75foot (23-meter) setback to potable water supply wells; but for agricultural reuse on non-food crops, Florida requires a 500-foot (150-meter) setback to potable water supply wells and a 100-foot (30-meter) setback to property lines. Florida will allow reduced setback distances for agricultural reuse on non-food crops if additional disinfection and reliability are provided or if alternative application techniques are used. Colorado recommends a 500-foot (150-meter) setback distance to domestic supply wells and a 100-foot (30-meter) setback to any irrigation well regardless of the quality of the reclaimed water. Due to the high degree of treatment required, Oregon and Nevada do not require setback distances when reclaimed water is used for unrestricted urban reuse or irrigation of food crops. However, setback distances are required for irrigation of non-food crops and restricted urban reuse. In Nevada, the quality requirements for reclaimed water are based not only on the type of reuse, but also on the setback distance. For example, for restricted urban reuse and a 100-foot (30-meter) buffer zone, Nevada requires that the reclaimed water have a mean fecal coliform count of no more than 23/100 ml and not exceed a maximum daily number of 240/100 ml. However, with no buffer zone, the reclaimed water must have a mean fecal coliform count of no more than 2.2/100 ml and not exceed a maximum daily number of 23/100 ml.


Groundwater Monitoring

Groundwater monitoring programs associated with reclaimed water irrigation generally focus on water quality in the surficial aquifer and are required by Alabama, Arkansas, Delaware, Florida, Hawaii, Illinois, Iowa, Massachusetts, Missouri, New York, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, West Virginia, and Wisconsin. In general, these groundwater monitoring programs require that 1 well be placed hydraulically upgradient of the reuse site to assess background and incoming groundwater conditions within the aquifer in question. In addition 2 wells must be placed hydraulically downgradient of the reuse site to monitor compliance. Florida normally requires a minimum of 3 monitoring wells at each reuse site. For reuse projects involving multiple sites, Florida may allow monitoring at selected example sites. Some states also require that a well be placed within each reuse site. South Carolina’s guidelines suggest that a minimum of 9 wells be placed in golf courses (18 holes) that irrigate with reclaimed water. Sampling parameters and frequency of sampling are generally considered on a case-by-case basis.


Suggested Guidelines for Water Reuse

Table 4-13 presents suggested wastewater treatment processes, reclaimed water quality, monitoring, and setback distances for various types of water reuse. Suggested guidelines are presented for the following categories:
„ „

Urban Reuse Restricted Access Area Irrigation


„ Agricultural Reuse - Food Crops



-Food crops not commercially processed -Commercially processed food crops and surface irrigation of orchards and vineyards
„ Agricultural Reuse – Non-Food Crops

„ Sound engineering practice

-Pasture for milking animals and fodder, fiber, and seed crops
„ „ „ „ „ „

These guidelines are not intended to be used as definitive water reclamation and reuse criteria. They are intended to provide reasonable guidance for water reuse opportunities, particularly in states that have not developed their own criteria or guidelines. Adverse health consequences associated with the reuse of raw or improperly treated wastewater are well documented. As a consequence, water reuse regulations and guidelines are principally directed at public health protection and generally are based on the control of pathogenic microorganisms for nonpotable reuse applications and control of both health significant microorganisms and chemical contaminants for indirect potable reuse applications. These guidelines address health protection via suggested wastewater treatment unit processes, reclaimed water quality limits, and other controls (setback distances, etc.). Both treatment processes and water quality limits are recommended for the following reasons:

Recreational Impoundments Landscape Impoundments Construction Uses Industrial Reuse Environmental Reuse Groundwater Recharge -Spreading or injection into aquifers not used for public water supply Indirect Potable Reuse -Spreading into potable aquifers -Injection into potable aquifers -Augmentation of surface supplies


These guidelines apply to domestic wastewater from municipal or other wastewater treatment facilities having a limited input of industrial waste. The suggested guidelines are predicated principally on water reclamation and reuse information from the U.S. and are intended to apply to reclamation and reuse facilities in the U.S. Local social, economic, regulatory, technological, and other conditions may limit the applicability of these guidelines in some countries (see Chapter 8). It is explicitly stated that the direct application of these suggested guidelines will not be used by the United States Agency for International Development (USAID) as strict criteria for funding. The suggested treatment processes, reclaimed water quality, monitoring frequency, and setback distances are based on:

Water quality criteria that include the use of surrogate parameters may not adequately characterize reclaimed water quality. known to produce reclaimed water of acceptable quality obviate the need to monitor the finished water for certain constituents, e.g., some health-significant chemical constituents or pathogenic microorganisms.

„ A combination of treatment and quality requirements


Expensive, time-consuming, and, in some cases, questionable monitoring for pathogenic organisms, such as viruses, is eliminated without compromising health protection.

„ Treatment reliability is enhanced.

Water reuse experience in the U.S. and elsewhere

„ Research and pilot plant or demonstration study data „

Technical material from the literature lines (see Appendix A)

„ Various states’ reuse regulations, policies, or guide-

It would be impractical to monitor reclaimed water for all of the chemical constituents and pathogenic organisms of concern, and surrogate parameters are universally accepted. In the U.S., total and fecal coliforms are the most commonly used indicator organisms in reclaimed water as a measure of disinfection efficiency. While coliforms are adequate indicator organisms for many bacterial pathogens, they are, by themselves, poor indicators of parasites and viruses. The total coliform analysis includes enumeration of organisms of both fecal and nonfecal origin, while the fecal coliform analysis is spe-


Table 4-13.

Suggested Guidelines for Water Reuse 1

Types of Reuse
Urban Reuse All types of landscape irrigation, (e.g., golf courses, parks, cemeteries) – also vehicle washing, toilet flushing, use in fire protection systems and commercial air conditioners, and other uses with similar access or exposure to the water Restricted Access Area Irrigation Sod farms, silviculture sites, and other areas where public access is prohibited, restricted or infrequent Agricultural Reuse – Food Crops Not Commercially Processed 15 Surface or spray irrigation of any food crop, including crops eaten raw. Agricultural Reuse – Food Crops Commercially 15 Processed Surface Irrigation of Orchards and Vineyards

Š Secondary 4 Š Filtration 5 Š Disinfection 6

Reclaimed 2 Water Quality
Š pH = 6-9 Š < 10 mg/l BOD 7 Š < 2 NTU 8 Š No detectable fecal 9,10 coli/100 ml Š 1 mg/l Cl2 residual (minimum)

Š pH - weekly Š BOD - weekly Š Turbidity continuous Š Coliform - daily Š Cl2 residual continuous

Reclaimed Water Monitoring

Setback 3 Distances
Š 50 ft (15 m) to potable water supply wells

Š See Table 2-7 for other recommended limits. Š At controlled-access irrigation sites where design and operational measures significantly reduce the potential of public contact with reclaimed water, a lower level of treatment, e.g., secondary treatment and disinfection to achieve < 14 fecal coli/100 ml, may be appropriate. Š Chemical (coagulant and/or polymer) addition prior to filtration may be necessary to meet water quality recommendations. Š The reclaimed water should not contain measurable levels of 12 viable pathogens. Š Reclaimed water should be clear and odorless. Š A higher chlorine residual and/or a longer contact time may be necessary to assure that viruses and parasites are inactivated or destroyed. Š A chlorine residual of 0.5 mg/l or greater in the distribution system is recommended to reduce odors, slime, and bacterial regrowth. Š See Section 3.4.3. for recommended treatment reliability. Š See Table 2-7 for other recommended limits. Š If spray irrigation, TSS less than 30 mg/l may be necessary to avoid clogging of sprinkler heads. Š See Section 3.4.3 for recommended treatment reliability.

Š Secondary 4 Š Disinfection 6

Š pH = 6-9 Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum) 11

Š pH - weekly Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š 300 ft (90 m) to potable water supply wells Š 100 ft (30 m) to areas accessible to the public (if spray irrigation)

Š Secondary 4 Š Filtration 5 Š Disinfection 6

Š pH = 6-9 Š < 10 mg/l BOD 7 Š < 2 NTU 8 Š No detectable fecal coli/100 ml 9,10 Š 1 mg/l Cl2 residual (minimum) 11

Š pH - weekly Š BOD - weekly Š Turbidity continuous Š Coliform - daily Š Cl2 residual continuous

Š 50 ft (15 m) to potable water supply wells

Š See Table 2-7 for other recommended limits. Š Chemical (coagulant and/or polymer) addition prior to filtration may be necessary to meet water quality recommendations. Š The reclaimed water should not contain measurable levels of viable pathogens. 12 Š A higher chlorine residual and/or a longer contact time may be necessary to assure that viruses and parasites are inactivated or destroyed. Š High nutrient levels may adversely affect some crops during certain growth stages. Š See Section 3.4.3 for recommended treatment reliability. Š See Table 2-7 for other recommended limits. Š If spray irrigation, TSS less than 30 mg/l may be necessary to avoid clogging of sprinkler heads. Š High nutrient levels may adversely affect some crops during certain growth stages. Š See Section 3.4.3 for recommended treatment reliability.

Š Secondary 4 6 Š Disinfection

Š pH = 6-9 Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum)

Š pH - weekly Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š 300 ft (90 m) to potable water supply wells Š 100 ft (30 m) to areas accessible to the public (if spray irrigation)

Agricultural Reuse – Nonfood Crops Pasture for milking animals; fodder, fiber, and seed crops

Š Secondary 4 Š Disinfection 6

Š pH = 6-9 Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum)

Š pH - weekly Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š 300 ft (90 m) to potable water supply wells Š 100 ft (30 m) to areas accessible to the public (if spray irrigation)

Š See Table 2-7 for other recommended limits. Š If spray irrigation, TSS less than 30 mg/l may be necessary to avoid clogging of sprinkler heads. Š High nutrient levels may adversely affect some crops during certain growth stages. Š Milking animals should be prohibited from grazing for 15 days after irrigation ceases. A higher level of disinfection, e.g., to achieve < 14 fecal coli/100 ml, should be provided if this waiting period is not adhered to. Š See Section 3.4.3 for recommended treatment reliability.


Table 4-13.

Suggested Guidelines for Water Reuse 1
Reclaimed Water Monitoring
Š pH - weekly Š BOD - weekly Š Turbidity continuous Š Coliform - daily Š Cl2 residual continuous

Types of Reuse
Recreational Impoundments Incidental contact (e.g., fishing and boating) and full body contact with reclaimed water allowed

Š Secondary 4 Š Filtration 5 Š Disinfection 6

Reclaimed 2 Water Quality
Š pH = 6-9 Š < 10 mg/l BOD 7 Š < 2 NTU 8 Š No detectable fecal coli/100 ml 9,10 Š 1 mg/l Cl2 residual (minimum) 11

Setback 3 Distances
Š 500 ft (150 m) to potable water supply wells (minimum) if bottom not sealed

Š Dechlorination may be necessary to protect aquatic species of flora and fauna. Š Reclaimed water should be non-irritating to skin and eyes. Š Reclaimed water should be clear and odorless. Š Nutrient removal may be necessary to avoid algae growth in impoundments. Š Chemical (coagulant and/or polymer) addition prior to filtration may be necessary to meet water quality recommendations. Š The reclaimed water should not contain measurable levels of viable pathogens. 12 Š A higher chlorine residual and/or a longer contact time may be necessary to assure that viruses and parasites are inactivated or destroyed. Š Fish caught in impoundments can be consumed. Š See Section 3.4.3. for recommended treatment reliability. Š Nutrient removal may be necessary to avoid algae growth in impoundments. Š Dechlorination may be necessary to protect aquatic species of flora and fauna. Š See Section 3.4.3 for recommended treatment reliability.

Landscape Impoundments Aesthetic impoundment where public contact with reclaimed water is not allowed Construction Use Soil compaction, dust control, washing aggregate, making concrete Industrial Reuse Once-through cooling

Š Secondary 4 Š Disinfection 6

Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum) 11

Š pH - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š 500 ft (150 m) to potable water supply wells (minimum) if bottom not sealed

Š Secondary 4 Š Disinfection 6

Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum) 11

Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š Worker contact with reclaimed water should be minimized. Š A higher level of disinfection, e.g., to achieve < 14 fecal coli/100 ml, should be provided when frequent work contact with reclaimed water is likely. Š See Section 3.4.3 for recommended treatment reliability.

Š Secondary 4 Š Disinfection 6

Š pH = 6-9 Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum) 11 ---------------------------Š Variable depends on recirculation ratio (see Section 2.2.1) pH = 6-9 Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14 Š 1 mg/l Cl2 residual (minimum) 11

▪ pH - weekly ▪ BOD - weekly ▪ TSS - daily ▪ Coliform - daily ▪ Cl2 residual continuous ---------------------Š pH - weekly Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous

Š 300 ft (90 m) to areas accessible to the public

Š Windblown spray should not reach areas accessible to workers or the public.

--------------------Recirculating cooling towers

-----------------------Š Secondary 4 Š Disinfection 6 (chemical coagulation 5 and filtration may be needed)

------------------------Š 300 ft (90 m) to areas accessible to the public. May be reduced or eliminated if high level of disinfection is provided.

----------------------------------------------------------------------------Š Windblown spray should not reach areas accessible to workers or the public. Š Additional treatment by user is usually provided to prevent scaling, corrosion, biological growths, fouling and foaming. Š See Section 3.4.3 for recommended treatment reliability.

Other Industrial Uses Environmental Reuse Wetlands, marshes, wildlife habitat, stream augmentation Š Variable Š Secondary 4 and disinfection 6 (minimum) Variable, but not to exceed: Š < 30 mg/l BOD 7 Š < 30 mg/l TSS Š < 200 fecal coli/100 ml 9,13,14

Depends on site specific uses (See Section 2.2.3) Š BOD - weekly Š TSS - daily Š Coliform - daily Š Cl2 residual continuous Š Dechlorination may be necessary to protect aquatic species of flora and fauna. Š Possible effects on groundwater should be evaluated. Š Receiving water quality requirements may necessitate additional treatment. Š The temperature of the reclaimed water should not adversely affect ecosystem. Š See Section 3.4.3 for recommended treatment reliability.


Table 4-13.

Suggested Guidelines for Water Reuse 1

Types of Reuse
Groundwater Recharge By spreading or injection into aquifers not used for public water supply Indirect Potable Reuse Groundwater recharge by spreading into potable aquifers

Š Site-specific and use dependent Š Primary (minimum) for spreading Š Secondary 4 (minimum) for injection Š Secondary 4 Š Disinfection 6 Š May also need filtration 5 and/or advanced wastewater treatment 16

Reclaimed Water Quality 2
Š Site-specific and use dependent

Reclaimed Water Monitoring
Š Depends on treatment and use

Setback Distances 3
Š Site-specific

Š Facility should be designed to ensure that no reclaimed water reaches potable water supply aquifers Š See Section 2.5 for more information. Š For spreading projects, secondary treatment may be needed to prevent clogging. Š For injection projects, filtration and disinfection may be needed to prevent clogging. Š See Section 3.4.3 for recommended treatment reliability. Š The depth to groundwater (i.e., thickness to the vadose zone) should be at least 6 feet (2 m) at the maximum groundwater mounding point. Š The reclaimed water should be retained underground for at least 6 months prior to withdrawal. Š Recommended treatment is site-specific and depends on factors such as type of soil, percolation rate, thickness of vadose zone, native groundwater quality, and dilution. Š Monitoring wells are necessary to detect the influence of the recharge operation on the groundwater. Š See Sections 2.5 and 2.6 for more information. Š The reclaimed water should not contain measurable levels of viable pathogens after percolation through the vadose zone. 12 Š See Section 3.4.3 for recommended treatment reliability.

Š Secondary 4 Š Disinfection 6 Š Meet drinking water standards after percolation through vadose zone

Includes, but not limited to, the following: Š pH - daily Š Coliform daily Š Cl2 residual continuous Š Drinking water standards quarterly Š Other 17 depends on constituent Š BOD - weekly Š Turbidity continuous Includes, but not limited to, the following: Š pH - daily Š Turbidity continuous Š Total coliform daily Š Cl2 residual continuous Š Drinking water standards quarterly Š Other 17 depends on constituent Includes, but not limited to, the following: Š pH - daily Š Turbidity continuous Š Total coliform daily Š Cl2 residual continuous Š Drinking water standards quarterly Š Other 17 depends on constituent

Š 500 ft (150 m) to extraction wells. May vary depending on treatment provided and site-specific conditions.

Indirect Potable Reuse Groundwater recharge by injection into potable aquifers

Š Secondary 4 Š Filtration 5 Š Disinfection 6 Š Advanced wastewater treatment 16

Includes, but not limited to, the following: Š pH = 6.5 - 8.5 Š < 2 NTU 8 Š No detectable total coli/100 ml 9,10 Š 1 mg/l Cl2 residual (minimum) 11 Š < 3 mg/l TOC Š < 0.2 mg/l TOX Š Meet drinking water standards

Š 2000 ft (600 m) to extraction wells. May vary depending on site-specific conditions.

Š The reclaimed water should be retained underground for at least 9 months prior to withdrawal. Š Monitoring wells are necessary to detect the influence of the recharge operation on the groundwater. Š Recommended quality limits should be met a the point of injection. Š The reclaimed water should not contain measurable levels of viable pathogens after percolation through the vadose zone. 12 Š See Sections 2.5 and 2.6 for more information. Š A higher chlorine residual and/or a longer contact time may be necessary to assure virus and protozoa inactivation. Š See Section 3.4.3 for recommended treatment reliability.

Indirect Potable Reuse Augmentation of surface supplies

Š Secondary 4 Š Filtration 5 Š Disinfection 6 Š Advanced wastewater treatment 16

Includes, but not limited to, the following: Š pH = 6.5 - 8.5 Š < 2 NTU 8 Š No detectable total coli/100 ml 9,10 Š 1 mg/l Cl2 residual (minimum) 11 Š < 3 mg/l TOC Š Meet drinking water standards

Š Site-specific

Š Recommended level of treatment is site-specific and depends on factors such as receiving water quality, time and distance to point of withdrawal, dilution and subsequent treatment prior to distribution for potable uses. Š The reclaimed water should not contain measurable levels of viable pathogens. 12 Š See Sections 2.6 for more information. Š A higher chlorine residual and/or a longer contact time may be necessary to assure virus and protozoa inactivation. Š See Section 3.4.3 for recommended treatment reliability.


Footnotes 1. These guidelines are based on water reclamation and reuse practices in the U.S., and they are especially directed at states that have not developed their own regulations or guidelines. While the guidelines should be useful in may areas outside the U.S., local conditions may limit the applicability of the guidelines in some countries (see Chapter 8). It is explicitly stated that the direct application of these suggested guidelines will not be used by USAID as strict criteria for funding. 2. Unless otherwise noted, recommended quality limits apply to the reclaimed water at the point of discharge from the treatment facility. 3. Setback distances are recommended to protect potable water supply sources from contamination and to protect humans from unreasonable health risks due to exposure to reclaimed water. 4. Secondary treatment processes include activated sludge processes, trickling filters, rotating biological contractors, and may include stabilization pond systems. Secondary treatment should produce effluent in which both the BOD and TSS do not exceed 30 mg/l. 5. Filtration means the passing of wastewater through natural undisturbed soils or filter media such as sand and/or anthracite, filter cloth, or the passing of wastewater through microfilters or other membrane processes. 6. Disinfection means the destruction, inactivation, or removal of pathogenic microorganisms by chemical, physical, or biological means. Disinfection may be accomplished by chlorination, UV radiation, ozonation, other chemical disinfectants, membrane processes, or other processes. The use of chlorine as defining the level of disinfection does not preclude the use of other disinfection processes as an acceptable means of providing disinfection for reclaimed water. 7. As determined from the 5-day BOD test. 8. The recommended turbidity limit should be met prior to disinfection. The average turbidity should be based on a 24-hour time period. The turbidity should not exceed 5 NTU at any time. If TSS is used in lieu of turbidity, the TSS should not exceed 5 mg/l. 9.Unless otherwise noted, recommended coliform limits are median values determined from the bacteriological results of the last 7 days for which analyses have been completed. Either the membrane filter or fermentation-tube technique may be used. 10. The number of fecal coliform organisms should not exceed 14/100 ml in any sample. 11. Total chlorine residual should be met after a minimum contact time of 30 minutes. 12. It is advisable to fully characterize the microbiological quality of the reclaimed water prior to implementa tion of a reuse program. 13. The number of fecal coliform organisms should not exceed 800/100 ml in any sample. 14. Some stabilization pond systems may be able to meet this coliform limit without disinfection. 15. Commercially processed food crops are those that, prior to sale to the public or others, have undergone chemical or physical processing sufficient to destroy pathogens. 16. Advanced wastewater treatment processes include chemical clarification, carbon adsorption, reverse osmosis and other membrane processes, air stripping, ultrafiltration, and ion exchange. 17. Monitoring should include inorganic and organic compounds, or classes of compounds, that are known or uspected to be toxic, carcinogenic, teratogenic, or mutagenic and are not included in the drinking water standards.


cific for coliform organisms of fecal origin. Therefore, fecal coliforms are better indicators of fecal contamination than total coliforms, and these guidelines use fecal coliform as the indicator organism. Either the multipletube fermentation technique or the membrane filter technique may be used to quantify the coliform levels in the reclaimed water. The Guidelines suggest that, regardless of the type of reclaimed water use, some level of disinfection should be provided to avoid adverse health consequences from inadvertent contact or accidental or intentional misuse of a water reuse system. For nonpotable uses of reclaimed water, 2 levels of disinfection are recommended. Reclaimed water used for applications where no direct public or worker contact with the water is expected should be disinfected to achieve an average fecal coliform concentration not exceeding 200/100 ml because:

that regulate drinking water standards for producing potable drinking water. These guidelines do not include suggested specific parasite or virus limits. Parasites have not been shown to be a problem at water reuse operations in the U.S. at the treatment and quality limits recommended in these guidelines, although there has been considerable interest in recent years regarding the occurrence and significance of Giardia and Cryptosporidium in reclaimed water. Viruses are of concern in reclaimed water, but virus limits are not recommended in these guidelines for the following reasons: A significant body of information exists indicating that viruses are reduced or inactivated to low or immeasurable levels via appropriate wastewater treatment, including filtration and disinfection (Yanko, 1993).
„ The identification and enumeration of viruses in waste-

Most bacterial pathogens will be destroyed or reduced to low or insignificant levels in the water The concentration of viable viruses will be reduced somewhat Disinfection of secondary effluent to this coliform level is readily achievable at minimal cost Significant health-related benefits associated with disinfection to lower, but not pathogen-free, levels are not obvious


water are hampered by relatively low virus recovery rates, the complexity and high cost of laboratory procedures, and the limited number of facilities having the personnel and equipment necessary to perform the analyses.
„ The laboratory culturing procedure to determine the



presence or absence of viruses in a water sample takes about 14 days, and an additional 14 days are required to identify the viruses.

For uses where direct or indirect contact with reclaimed water is likely or expected, and for dual water systems where there is a potential for cross-connections with potable water lines, disinfection to produce reclaimed water having no detectable fecal coliform organisms per 100 ml is recommended. This more restrictive disinfection level is intended for use in conjunction with tertiary treatment and other water quality limits, such as a turbidity less than or equal to 2 NTU in the wastewater prior to disinfection. This combination of treatment and use of water quality limits has been shown to produce reclaimed water that is essentially free of measurable levels of bacterial and viral pathogens. For indirect potable uses of reclaimed water, where reclaimed water is intentionally introduced into the raw water supply for the purposes of increasing the total volume of water available for potable use, disinfection to produce reclaimed water having no detectable total coliform organisms per 100 ml is recommended. Total coliform is recommended, in lieu of fecal coliform, to be consistent with the Safe Drinking Water Act (SDWA) National Primary Drinking Water Regulations (NPDWR)

While recombinant DNA technology provides new tools to rapidly detect viruses in water (e.g., nucleic acid probes and polymerase chain reaction technology), methods currently in use are not able to quantify viruses or differentiate between infective and noninfective virus particles. ing the health significance of low levels of viruses in reclaimed water.

„ There is no consensus among virus experts regard-

„ There

have been no documented cases of viral disease resulting from the reuse of wastewater at any of the water reuse operations in the U.S.

The removal of suspended matter is related to the virus issue. Many pathogens are particulate-associated and that particulate matter can shield both bacteria and viruses from disinfectants such as chlorine and UV radiation. Also, organic matter consumes chlorine, thus making less of the disinfectant available for disinfection. There is general agreement that particulate matter should be reduced to low levels, e.g., 2 NTU or 5 mg/l TSS, prior to disinfection to ensure reliable destruction of patho-


genic microorganisms during the disinfection process. Suspended solids measurements are typically performed daily on a composite sample and only reflect an average value. Continuously monitored turbidity is superior to daily suspended solids measurements as an aid to treatment operation. The need to remove organic matter is related to the type of reuse. Some of the adverse effects associated with organic substances are that they are aesthetically displeasing (may be malodorous and impart color), provide food for microorganisms, adversely affect disinfection processes, and consume oxygen. The recommended BOD limit is intended to indicate that the organic matter has been stabilized, is nonputrescible, and has been lowered to levels commensurate with anticipated types of reuse. TSS limits are suggested as a measure of organic and inorganic particulate matter in reclaimed water that has received secondary treatment. The recommended BOD and TSS limits are readily achievable at well operated water reclamation plants. The suggested setback distances are somewhat subjective. They are intended to protect drinking water supplies from contamination and, where appropriate, to protect humans from exposure to the reclaimed water. While studies indicate the health risk associated with aerosols from spray irrigation sites using reclaimed water is low, the general practice is to limit, through design or operational controls, exposure to aerosols and windblown spray produced from reclaimed water that is not highly disinfected. Unplanned or incidental indirect potable reuse occurs in many states in the U.S., while planned or intentional indirect potable reuse via groundwater recharge or augmentation of surface supplies is a less-widely accepted practice. Whereas the water quality requirements for nonpotable water uses are tractable and not likely to change significantly in the future, the number of water quality constituents to be monitored in drinking water (and, hence, reclaimed water intended for potable reuse) will increase and quality requirements will become more restrictive. Consequently, it would not be prudent to suggest a complete list of reclaimed water quality limits for all constituents of concern. Some general and specific information is provided in the guidelines to indicate the extensive treatment, water quality, and other requirements that are likely to be imposed where indirect potable reuse is contemplated.


Pathogens and Emerging Pollutants of Concern (EPOC)

As needs for alternative water supplies grow, reclaimed water will be used more in both direct nonpotable applications and indirect potable reuse projects. Future monitoring for pathogens and other EPOCs will likely be necessary to ensure that reclaimed water is a safe water source. For example, California regulations require monthly sampling and analysis for Giardia, enteric viruses, and Cryptosporidium for the use of reclaimed water for impoundments during the first year of operation (State of California, 2000). After the first year, the reclaimed water may be sampled and analyzed quarterly and monitoring may be discontinued after 2 years of operation with the approval of the California Department of Health Services (DHS). As previously discussed, Florida requires monitoring of Giardia and Cryptosporidium with sampling frequency based on treatment plant capacity for specific types of reuse. The DHS updated the draft regulations for Groundwater Recharge Reuse in July 2003 to require monitoring of EPOCs. Each quarter, during the first year of operation, the reclaimed water shall be analyzed for: unregulated chemicals; priority toxic pollutants; chemicals with state action levels; and other chemicals that the DHS has specified (California DHS, 2003). Chemicals with state action levels are defined as chemicals that have been detected at least once in drinking water supplies or chemicals of interest for some specific reason. The other chemicals as specified by the DHS include N-Nitrosodiethylamine (NDEA) and N-Nitrosopyrrolidine. The draft regulations also require annual monitoring of pharmaceuticals, endocrine disrupting chemicals, and other chemical indicators of municipal wastewater presence. The draft regulations state that these samples are being collected for information purposes, and there are no standards for the contaminants listed and no standards anticipated at this time (California DHS, 2003). Although no illnesses to date have been directly connected to the use of reclaimed water, in order to better define pathogens and EPOCs contained in reclaimed water, it is recommended to continue with ongoing research and additional monitoring for Giardia , Cryptosporidium, and other EPOCs.


Pilot Testing

Because it is desirable to fully characterize the reclaimed water to be produced and to compare its quality to other water sources in the area, pilot testing should be conducted in support of some of the more sensitive types of


reuse, like groundwater recharge by injection and indirect potable reuse. Pilot testing can be used to demonstrate the ability of the selected unit processes to meet project objectives and to refine the design of sophisticated treatment trains. Pilot testing also can be used to demonstrate the ability of the treatment and disinfection units to effectively control pathogens and organic compounds. As part of this activity, the EPOCs, including pharmaceutically active substances, endocrine disrupters, and personal care products, can be evaluated. Ideally, pilot testing should build on previous work as opposed to repeating it.



California Department of Health Services. 2003. Groundwater Recharge Reuse Regulations July 2003 Draft, Title 22, California Code of Regulations, Division 4. Environmental Health, Chapter 3. Recycling Criteria. California State Water Resources Control Board. 2000. California Municipal Wastewater Reclamation Survey. index.html. Florida Department of Environmental Protection. 2002. 2001 Reuse Inventory. reuse/. Hilger, H.A., 2003. “An Assessment of North Carolina Water Reuse Regulations: Their Application to a New Reclamation Facility and Their Key Features Compared to Other State Reuse Regulations,” North Carolina Water Resources Research Institute, Raleigh, North Carolina. Perlman, H.A., Pierce, R.R., and Solley, W.B. 1998. Estimated Use of Water in the U.S. in 1995. U.S. Geological Survey Circular 1200. State of California. 2000. California Code of Regulations, Title 22, Division 4, Environmental Health, Chapter 3 Recycling Criteria. Van Riper, C., G. Schlender and M. Walther, 1998. “Evolution of Water Reuse Regulations in Washington State.” WateReuse Conference Proceedings, AWWA, Denver, Colorado. Yanko, W.A. 1993. “Analysis of 10 Years of Virus Monitoring Data from Los Angeles County Treatment Plants Meeting California Wastewater Reclamation Criteria.” Water Environ. Research, 65(3):221-226.



CHAPTER 5 Legal and Institutional Issues
Although specific laws vary widely, most states have adopted a number of rules and policies that both support and challenge the development of reclaimed water projects. Since public health regulations are reviewed in detail in Chapter 4, this chapter focuses on other issues that emerge during the various stages of planning and implementing water reuse projects, including relevant rules promulgated by federal, state, and local jurisdictions. Laws, policies, rules, and regulations that affect project planning include water rights laws, water use, and wastewater discharge regulations, as well as laws that restrict land use and protect the environment. Included in project implementation issues are policies that guide the development of reclaimed water rates and agreements between reclaimed water producers, wholesalers, retailers, and customers, as well as rules affecting system construction and liability for water reuse. Some legal matters are quite technical, and the body of statutory and case law in the area of water reuse is relatively small. The majority of the rules and policies are focused on areas where water reuse has been practiced, and expansion to other areas might raise issues not discussed here. Therefore, managers should carefully consider the legal and institutional aspects of a new reuse project, and obtain counsel to help weigh alternatives and risks. However, even a review of the basic issues should allow reuse planners to identify the most important questions early in the planning process where they can be most effectively addressed. This section also expands upon the following guidelines that can assist managers in addressing legal and institutional issues during the planning and implementation phases of a reuse system:
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Forging and maintaining contact with the appropriate agencies Developing a realistic schedule Assessing cash flow needs Considering institutional structure Identifying steps to minimize liability Preparing contracts

„ „ „ „ „


Water Rights Law

A water right is a right to use water – it is not a right of ownership. In the U.S., the state generally retains ownership of “natural” or public water within its boundaries, and state statutes, regulations, and case law govern the allocation and administration of the rights of private parties and governmental entities to use such water. A “water right” allows water to be diverted at one or more particular points and a portion of the water to be used for one or more particular purposes. A basic doctrine in water rights law is that harm cannot be rendered upon others who have a claim to the water. Water rights are an especially important issue since the rights allocated by the states can either promote reuse measures, or they can pose an obstacle. For example, in water-limited areas, where water reuse might be most attractive, water rights laws might prohibit the use of potable water for nonpotable purposes, while at the same time restricting the use of reclaimed water in a consumptive fashion that prevents its return to the stream. State laws allocate water based on 2 types of rights – the appropriative doctrine and the riparian doctrine. These will be described in general terms, after which there will be a brief analysis of their application to water reuse projects.

Identifying the legal and institutional drivers for reuse Developing a public education program




Appropriative Rights System


The appropriative rights system is found in most western states and in areas that are water-limited. (California has both appropriative and riparian rights.) It is a system by which the right to use water is appropriated – that is, it is assigned or delegated to the consumer. The basic notion is first in time, first in right. In other words, the right derives from beneficial use on a first-come, first-served basis and not from the property’s proximity to the water source. The first party to use the water has the most senior claim to that water. The senior users have a continued right to the water, and a “late” user generally cannot diminish the quantity or quality of the water to the senior user. This assures that senior users have adequate water under almost any rainfall conditions, and that later users have some moderate assurance to the water. The last to obtain water rights may be limited to water only during times when it is available (wet season). The right is for a specific quantity of water, but the appropriator may not divert more water than can be used. If the appropriated water is not used, it will be lost. Generally, appropriative water rights are acquired pursuant to statutory law; thus, there are comprehensive water codes that govern the acquisition and control of the water rights. The acquisition of the water right is usually accompanied by an application to state officials responsible for water rights and granted with a permit or license. The appropriative rights doctrine allows for obtaining water by putting it to beneficial use in accordance with procedures set forth in state statutes and judicial decisions. The appropriative water rights system is generally used for groundwater throughout the U.S. Water percolating through the ground is controlled by 3 different appropriative methods: absolute ownership, reasonable use rule, or specific use rule. Absolute ownership occurs when the water located directly beneath a property belongs to the property owner to use in any amount, regardless of the effect on the water table of the adjacent land, as long as it is not for a malicious use. The reasonable use rule limits groundwater withdrawal to the quantity necessary for reasonable and beneficial use in connection with the land located above the water. Water cannot be wasted or exported. The specific use rule occurs when water use is restricted to one use. During times of excess water supply, storage alternatives may be considered as part of the reuse project so that water may be used at a later date. A determination of the ownership or rights to use this stored reclaimed water will need to be made when considering this alter-


Riparian Rights System

The riparian water rights system is found primarily in the east and in water-abundant areas. The right is based on the proximity to water and is acquired by the purchase of the land. A riparian user is not entitled to make any use of the water that substantially depletes the stream flow or that significantly degrades the quality of the stream. Such riparian use can only be for a legal and beneficial purpose. The right of one riparian owner is generally correlative with the rights of the other riparian owners, with each landowner being assured some water when available. Water used under a riparian right can be used only on the riparian land and cannot be extended to another property. However, unlike the appropriative doctrine, the right to the unused water can be held indefinitely and without forfeiture. This limits the ability of the water authority to quantify the amount of water that has a hold against it and can lead to water being allocated in excess of that available. This doctrine does not allow for storage of water.


Water Rights and Water Reuse

In arid parts of the western U.S., reclaimed water often constitutes a more reliable supply than rights to surface water or groundwater granted by a water authority. This is particularly true when a user has low-priority rights that are curtailed or withdrawn in times of shortage. (Such subordinate rights are sometimes referred to as “paper water” as opposed to “wet water” which refers to the possession of an actual supply.) Because of the difficulty in obtaining an uninterrupted supply, reclaimed water has simultaneously become an attractive alternative water source and the largest block of unappropriated water in the West. Consequently, it is important to understand who retains control of the reclaimed water among the discharger, water supplier, other appropriators, and environmental interests. For example, in Washington State, the municipal corporation of the City of Walla Walla was taken to court by a local irrigation district that wanted the city to continue to discharge wastewater effluent into Mill Creek, a natural channel, for irrigation use. The court decreed on 2 occasions that the city must discharge all of its wastewater effluent, at all seasons of the year, into the creek (Superior Court of the State of Washington, 1927 and 1971). According to Colgne and MacLaggan (1995) the downstream water user’s right to reclaimed water depends on the state’s water allocation system:


Some states issue permits to the owners of reclaimed water or to appropriators of it when discharged into a natural water course. These states granting permits to the appropriators of reclaimed water do so treating such discharges into a reclaimed watercourse as if it has been abandoned and thus available for appropriation. Other states issue appropriation permits containing a provision that clarifies that the permit does not, in itself, give the permittee a right against a party discharging water upstream who may cease to discharge the water to the watercourse in the future. In other words, state law can either promote or constrain reuse projects depending on how its system of water rights regards the use and return of reclaimed water. In general, the owner of a wastewater treatment plant that produces effluent is generally considered to have first rights to its use and is not usually bound to continue its discharge. However, when a discharger’s right to reuse is constrained, such restrictions are usually based on issues resulting from one of the following scenarios:

propriative law, and in times of water shortage, it is possible that a more important use could make claim to reclaimed water that, for example, is being used for industrial process water.

Reduced Withdrawal – A water reuse program that reduces withdrawals from the water supply will probably pose no third-party conflict with water rights issues, but the impact of such reductions on projectproponent water rights should be evaluated. In some instances, such as when water rights or allocations are based on historic usage, reductions could jeopardize the amount of water a customer is entitled to, especially during times of drought. This has a negative effect on the marketing of reclaimed water. Therefore, where possible, assurances should be made that historic allocations will not be reduced to the point that the customer will suffer damage during periods of shortage.


Federal Water Rights Issues

Reduced Discharge – Reduction or elimination of effluent discharge flows due to certain types of reuse (e.g. evaporative cooling, groundwater infiltration) could result in legal challenges from downstream users, especially when the reduced flow results in serious economic losses or negative impacts on the environment. When the use of reclaimed water reduces or eliminates the discharge of wastewater to the watercourse, downstream users may make claim damages against the owner of the reuse project. The nature of the legal challenge would depend on the water rights system used. These issues are less well defined for groundwater than for streams and rivers. Changes in Point-of-Discharge or Place-of-Use – Occurs in states with appropriative rights where laws are designed to protect the origin of the water by limiting the place-of-use or by requiring the same point of discharge. In riparian states, the place-ofuse can also be an issue when reclaimed water is distributed to users located outside the watershed from which the water was originally drawn. Hierarchy of Use – Generally with water reuse, the concepts of “reasonable use” and “beneficial use” should not present an obstacle, particularly if such reuse is economically justified. Nevertheless, a hierarchy of use still exists in both riparian and ap-

Although most water rights issues are decided according to state law, in certain cases federal water laws may impact the planning of water reuse projects. This most often occurs when the project augments, reduces, or otherwise impacts the supply of water to more than one state, to protected Native American tribes, or to other countries. In addition to these areas of federal involvement, the federal government also has the right to adequate water from sources on or adjacent to its own property to meet the required needs of the land. Some of the water rights laws that may apply to this situation are listed below.
„ Multi-State and Federal Water Allocations – The fed-



eral government may claim jurisdiction in disputes between states regarding the allocation of limited water supplies. This has been particularly true in the West where 5 states (Arizona, California, Colorado, Nevada, and Utah) are served by the Colorado River where the flow is not always sufficient to supply all the nominal allocations. A federal interest may also be invoked when water owned by the federal government is allocated to various parties within the same state. In such cases, the federal government may serve as the “honest broker” between parties. Or, in instances were the federal interest is strong enough, the government may support the implementation of an appropriate solution to allocation conflicts by funding recommended improvements. In either situation, the availability of alternative water supplies (e.g. reclaimed water) may constitute an important factor in determining water rights and entitlements. (This is also discussed in


Section 5.2 “Water Supply and Use.”)
„ Native American Water Rights – Although there have

been many court decisions relating to the water rights of Indian reservations and other federal lands, there is still a great deal of uncertainty as to how these decisions should be interpreted. If there is a possibility that a water reuse project will conflict with the federal reserved water rights, either from an Indian reservation or other federal reserve, a very careful legal interpretation of such water rights should be obtained.

served or reused. Often these standards serve to promote reuse by requiring water users to reduce their total or per capita water use as compared to an established baseline. In some cases, certain uses of potable water (i.e., irrigation, power plant cooling) are considered “unreasonable” and are prohibited unless other, nonpotable sources have been determined to be “environmentally undesirable or economically unsound” (California Water Code Section 13550). There are 3 main types of water supply and use rules discussed here:
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International Water Rights – Another area of federal interest with respect to water rights is in the distribution of water supplies across state lines, or in international or boundary waters (e.g. the Great Lakes, the Tijuana River). In such situations, where the use of reclaimed water might reduce the access to water supply between states, or to another nation, federal jurisdiction may be imposed. Water Rights on Federal Property – Referred to as federal reserved water rights, the quantity of water reserved by the federal government does not have to be established at the time of the land’s acquisition. In addition, these water rights are not lost due to non-use or abandonment and can be designated for purposes other than that which they were originally intended, as long as consumption does not increase. These rights may be set aside by executive order, statute, treaty, or agreement (Weinberg and Allan, 1990). Water may also be appropriated by the federal government for purposes established by Congress and carried out on non-reserved lands. Like the water rights associated with federal reserves, this right to water for non-reserved lands may not cause harm to other water users and the appropriation may not take priority over already existing appropriations. There is some question as to whether there is sufficient legal basis for claiming water under the non-reserved rights scenario.

Water supply reductions Water efficiency goals Water use restrictions


Water Supply Reductions


Water supply reductions are often imposed during periods of drought. For example, Florida has identified water conservation goals for the water management districts to implement (FDEP, 1999). To meet these goals and to help ensure that enough water is available to meet anticipated potable water demands, Florida issued a water shortage order in 2001 to limit the number of irrigation days per week. Where water shortages are common, cutbacks may be imposed by statute, or they may be written into water allocation agreements between the various parties, (e.g., Colorado River Agreement, Monterey Agreement). During such times, appropriate water rights may be invoked so that the senior rightsholders receive their full allocations, or have their allocations reduced less than those with more junior rights. Whatever the cause, water shortages often provide a powerful incentive to implement water reuse projects to augment supplies, especially where reductions are frequent and other less costly methods (e.g., water conservation) have already been implemented. When the supply is curtailed by the federal or state government, local water agencies may adopt tiered rates, priority categories, and other pricing and allocation strategies to minimize the impact of drought on customers by making sure that water is available for firefighting, public health, and other critical purposes. One side effect of such restrictions is an increased public awareness of the cost associated with water supply—costs that water reuse projects can help to avoid. The frequency of restrictions can also help planners evaluate the risk of such shortages, which in turn can increase the calculated value of the reuse projects.


Water Supply and Use Regulations

Water supply and use legislation in the context of the Guidelines is distinct from water rights law in that it covers policies and regulations, which determine how an agency or entity with water rights may decide to distribute that supply to various parties. Over the past decade, it has become increasingly common for federal, state, and even local entities to set standards for how water may be used as a condition of supplying water to its customers, including the extent to which it must be con-



Water Efficiency Goals

Water efficiency goals can be either mandatory or voluntary. When voluntary goals (or targets) are promulgated, public support for conservation and reuse are usually stimulated by advertising or outreach campaigns designed to underscore the importance of protecting limited supplies. When mandatory goals are set, however, compliance is related to fees and availability of service. On a local level, the consequences for failing to meet mandatory goals can range from higher use fees (e.g. tiered water rates, surcharges) to termination of service. Where water efficiency is required on a state level, incentives are frequently used to encourage compliance, and meeting certain targets is a prerequisite for qualifying for grants or loans or even for receiving a greater percent of an agency’s normal allocation. When water reuse projects are planned in areas where voluntary or mandatory goals are in place, project managers should be sure that the proposed reuse types qualify as water efficiency measures so that reclaimed water customers can take advantage of the resulting benefits.

ties or consequences result from non-compliance. In the case of local water restrictions, it may not be necessary to test the enforceability of the statutes, since the potential consequences of non-compliance may be sufficient to persuade most customers to use reclaimed water for appropriate purposes. Otherwise, penalties should be specified at a level adequate to deter violation. Such penalties may include disconnection of service and a fee for reconnection with fines and jail time for major infractions (e.g., Mesa, Arizona and Brevard County, Florida). However, other regulations designed to protect water customers from termination may mitigate or even neutralize that particular penalty option. Where local ordinances require the use of reclaimed water, they may also include a variety of other requirements regulating its supply and use, including rules for customer connection, inspection, and facility management. Many cities require customers within a given distance of existing or proposed reclaimed water pipes to connect to the reclaimed water system. This may be coupled with restrictions on the use of potable water for nonpotable purposes, such as irrigation. Some cities have gone as far as to prohibit the use of other nonpotable water (i.e. groundwater or surface water) where reclaimed water is available. These rules are examined more closely in a later section, 5.5.3 Customer Agreements.


Water Use Restrictions

Water use restrictions may either prohibit the use of potable water for certain purposes, or require the use of reclaimed water in place of potable water. Ordinances requiring water reuse, however, generally allow otherwise prohibited and “unreasonable” uses of potable water to occur when reclaimed water is unavailable, is unsuitable for the specific use, is uneconomical, or when its use would have a negative impact on the environment. On a federal level, there have been discussions in recent years on encouraging the passage of federal water use restrictions as part of a “green building” regulation, such that all federally-sponsored projects must evaluate the use of reclaimed water during the planning process. However, no such rules have yet been proposed. On a state level, water use restrictions are important because they give local jurisdictions a legal foundation for regulating local use. They may also be effective in promoting water reuse, particularly when such rules also require state agencies to evaluate alternative supplies for all state-funded projects. Local water use restrictions can help to encourage reuse when the practice is generally accepted and readily available at a cost below other supplies. However, an important consideration in evaluating the implementation of such restrictions is deciding what type of penal-


Wastewater Regulations

Both federal and state agencies exercise jurisdiction over the quality and quantity of wastewater discharge into public waterways. The primary authority for the regulation of wastewater is the Federal Water Pollution Control Act, commonly referred to as the Clean Water Act (CWA) (Public Law 92-500). While the legislative origin of the CWA stretches back to the Rivers and Harbors Act of 1899, the 1972 CWA assigned the federal government specific responsibilities for water quality management designed to make all surface waters “fishable and swimmable” (Cologne and MacLaggan, 1995). The CWA requires states to set water quality standards, thus establishing the right to control pollution from wastewater treatment plants, as long as such regulations are at least as stringent as federal rules. Primary jurisdiction under the CWA is with the EPA, but in most states the CWA is administered and enforced by the state water pollution control agencies. Wastewater discharge regulations mostly address treated effluent quality—specifically the removal of chemical pollutants and biological pathogens that could have a deleterious effect on receiving waters. Even in regions of the U.S. where rainfall is plentiful (i.e., Florida),


regulations that establish criteria for discharged wastewater water quality can provide a powerful incentive to reuse treated effluent. Although less common, discharge permits may also restrict the quantity of effluent discharged to a receiving body to limit its effect on the local ecosystem. Such regulations may be continuous or seasonal, and may or may not correspond to a period when reclaimed water is in demand. As with water quality limits, it is important for those planning reuse projects to meet with treatment plant managers to understand the extent of discharge limitations and how they may be alleviated by supplying treated effluent for reuse.


Effluent Quality Limits

Wastewater discharge regulations are important to water reuse managers for a number of reasons. First, reuse projects can be implemented as an alternative to high levels of treatment when discharge regulations require advanced treatment methods, such as nutrient removal. Second, the level of treatment required by the NPDES permit may be adequate to meet most health regulations, reducing the investment needed to meet reuse standards. By the same token, the level of reliability required by NPDES standards may be less rigorous than what paying customers expect, so that supplementary treatment systems are needed to ensure continuous production. These issues should be thoroughly explored by those planning water reuse projects prior to project design and implementation.

The CWA regulates discharge of pollutants into navigable waters through permits issued pursuant to the National Pollution Discharge Elimination System (NPDES). Under the CWA, the term “navigable waters” means waters of the U.S. The federal courts follow the Tenth Circuit Court’s conclusion that this definition is an expression of congressional intent “to regulate discharges made into every creek, stream, river or body of water that in any way may affect interstate commerce” (United States vs. Earth Sciences Inc., 1979). The goal of the CWA is to “restore and maintain the chemical, physical and biologic integrity of the nation’s waters.” The CWA sets forth specific goals to conserve water and reduce pollutant discharges and directs the EPA Administrator to assist with the development and implementation of water reclamation plans, which will achieve those goals. Major objectives of the CWA are to eliminate all pollutant discharges into navigable waters, stop discharges of toxic pollutants in toxic amounts, develop waste treatment management plans to control sources of pollutants, and to encourage water reclamation and reuse. Pursuant to this goal, the EPA has evaluated major waterways in the U.S. to determine which ones fail to meet federal water quality standards. Waterbodies listed as “impaired” according to Section 303(d) of the CWA are protected by strict limits on the discharge of the specific pollutants of concern that could further degrade their water quality. In addition to limits on the concentration of specific contaminants, discharge regulations may also include limits on the total mass of a pollutant discharged to the receiving stream – known as total maximum daily load (TMDL) limits – and on the quality of the water in the receiving stream itself (e.g. minimum dissolved oxygen limits). These regulations are usually the result of extended negotiations between federal, state, and local agencies.


Effluent Flow Limits

Although less common than water quality regulations, the quantity of treatment plant effluent discharged to a receiving body may also be limited by regulation, such as the Endangered Species Act (ESA). Such regulations may be continuous or seasonal, and may or may not correspond to periods associated with reclaimed water demand as required by the NPDES permit. For instance, state regulators in California required the San Jose/Santa Clara Water Pollution Control Plant (serving the Silicon Valley area of northern California) to reuse treated effluent as an alternative to limiting discharge into the south end of San Francisco Bay during the summer dry-weather period (May through October). In this instance the limitation was due not to contaminants, but to the fact that the point of discharge was a saltwater marsh which was made brackish by the discharge of relatively fresh treated effluent. The salt marsh in question is home to 2 endangered species (Rosenblum, 1998). Further discussion of the Endangered Species Act is in Section 5.4.2. Effluent quantity may also be limited due to the demand for the reclaimed water by communities in the area. In a 1984 decision by the California State Water Resources Control Board, the Fallbrook Sanitary District (a wastewater discharger near San Diego) was enjoined to show cause why their treated effluent was discharged to the Pacific Ocean rather than made available for reuse by the local community. As discussed in the citation above, the foundation of this ruling (which has not been tested by the courts) lies with that state’s prohibition against wasting water and the “unreasonable” use of potable water when reclaimed water is available. This case also illustrates a trend towards viewing water of any quality suitable for some type of reuse, such that its discharge may be limited for the sake of preserving a scarce public resource.



Safe Drinking Water Act – Source Water Protection

In 1996, the 104th Congress reauthorized and amended Title XIV of the Public Health Services Act (commonly known as the Safe Drinking Water Act). One of the amendments included was Section 132, Source Water Assessment, which requires that the EPA administrator publish guidance for states exercising primary enforcement responsibility for public water systems to carry out directly or through delegation, (for the protection and benefit of public water systems and for the support of monitoring flexibility), a source water assessment program within the state’s boundaries. The program requirements include: (a) delineating the boundaries of the assessment areas in such state from which one or more public water systems in the state receive supplies of drinking water, using all reasonably available hydrogeologic information on the sources of the supply and the water flow, recharge, discharge, and any other reliable information deemed necessary to adequately determine such areas; and (b) identifying contaminants regulated under this title for which monitoring is required under this title or any unregulated contaminants which the state has determined may present a threat to public health. To the extent practical, the origins of such contaminants within each delineated area should be determined so that the susceptibility of the public water systems to such contaminants can be decided. A state may establish a petition program under which a community water system, municipal or local government, or political subdivision of a state may submit a source water quality protection partnership petition requesting state assistance in the development of a voluntary, incentive-based partnership to reduce the presence of drinking water contaminants, and to obtain financial or technical assistance necessary to set up the source water of a community water system. A petition may only address contaminants that are pathogenic organisms for which regulations are established, or for which regulations have been proposed or promulgated and are detected by adequate monitoring methods in the source water at the intake structure or in any community water system collection, treatment storage, or distribution facilities at levels above the maximum contaminant level (MCL), or that are not reliable and consistently below the MCL.

mulgated and enforced by federal and state governments, most land use regulations are developed and enforced by local jurisdictions. But while they are generally considered to be local matters, land use decisions are always made in the context of federal environmental laws and state planning regulations that also influence their determination. The following section reviews the key elements of local land use planning, as well as the underlying environmental regulations and their effect on planning reclaimed water projects.


General and Specific Plans

Most communities in the U.S. engage in some type of structured planning process whereby the local jurisdiction regulates development according to a general plan. A general plan is designed to serve as “a basis for rational decisions regarding a city’s or county’s long-term physical development [and] embodies public policy relative to the distribution of future land uses, both public and private” (State of California, 1998 and State of Florida, 2002). General plans can be adopted by ordinance and are sometimes reinforced with zoning regulations and similar restrictions. In some states, communities are legally required to adopt these general plans, and projects that significantly deviate from them must be rejected, modified, or permitted by variance. The cost of extending utilities into undeveloped areas is an important criterion when deciding where to permit development in a community, as is the availability of resources. Even after a general plan is adopted and an area is planned for a particular type of development, developers may be required to prepare specific plans that demonstrate sufficient water supply or wastewater treatment capacity to meet the needs of their developments. Several western states have also adopted laws that require communities to adopt water management plans and identify additional supplies to support new developments. Such rules actually encourage the implementation of reuse projects that reduce the use of limited resources. In chronically water-short or environmentally sensitive areas, use of reclaimed water may even be a prerequisite for new developments. However, the local planning process can also pose a challenge to reuse projects by subjecting them to the scrutiny of a public that may have many misconceptions about reclaimed water. Federal and state environmental assessment regulations (which are often included in the local planning process) require public notice of published plans and advertised hearings to solicit opinion from all parties potentially affected by the proposed project. It is not unusual at such hearings to hear opposition to the use of reclaimed water for rea-


Land Use and Environmental Regulations

Land use policies regulate the development and use of property which might be served by reclaimed water systems. Unlike water and wastewater laws that are pro-


sons ranging from health effects to growth inducement to environmental justice. These concerns often mask underlying worries about growth or political issues that may be hard to deal with directly. However, unless the specific concerns are thoroughly addressed in the planning process, it is unlikely that the project will proceed to the point that the underlying issues can emerge to be dealt with. Furthermore, failure of a reuse project to conform to general plan guidelines and local requirements will render the project vulnerable to challenge in the courts or to appeal before the regulatory bodies even after the project is approved.

ticularly important when evaluating the economics of reuse projects to consider how reclaimed water serves to augment water supply and divert wastewater from impacted waters, and to include both direct and indirect benefits. The evaluation should include the consideration of preserving a habitat that might be depleted by importing surface water supplies or the avoided cost of mitigating such an impact. A steady stream of research has appeared in the literature during the past decade suggesting appropriate methods of contingent valuation for environmental benefits (Sheikh et al., 1998). On the other hand, environmental assessment regulations also require the careful assessment of any negative impacts of reclaimed water projects. Examples of common environmental impacts include the visual impact of tanks and reservoirs and the disturbance of underground cultural resources and hazardous materials by underground pipelines. Less common, but equally significant, projects that provide reclaimed water for irrigation over unconfined aquifers are sometimes required to demonstrate that use of nonpotable water will not contribute to the degradation of underlying groundwater. In such cases, mitigation may include a monitoring program or even additional treatment to match groundwater quality. Rules to protect aquifers from infiltration by reclaimed water may also be adopted. The manager of a reclaimed water project must be familiar with not only the federal and state regulations guiding the environmental assessment process, but also their interpretation by the local jurisdiction. For example, the federal NEPA process requires a public scoping, dissemination of a Notice of Intent, and at least one public meeting preceding the solicitation and consideration of public comments on project impacts and their mitigation. By contrast, the California Environmental Quality Act (CEQA) mandates specific periods during which project information must be published and encourages—but does not require—formal hearings during project review. However, many lead agencies do conduct public hearings on environmental assessment reports, either independently or in the course of their own public planning process (California Department of Water Resources, 2002 and State of Florida, 2002). Public review requirements have a significant effect on project schedules. In addition to the time required to assemble site information and assess the potential impacts of the project, there are mandatory public review periods that range from 1 to 6 months depending on the nature of the impact and the type of permit required. A comprehensive implementation schedule should be


Environmental Regulations

A number of state and federal environmental regulations promote the use of reclaimed water by limiting the amount of water available to communities or restricting the discharge of wastewater into receiving streams. The ESA in particular has been applied to require water users to maintain minimum flows in western rivers to protect the habitat of various species of fish whose survival is threatened by increases in water temperature and restricted access to breeding grounds. Similarly, as noted previously, the provisions of the CWA can impose limits on both the quality and quantity of treated effluent an agency is allowed to discharge. A community with limited water supply or wastewater treatment capabilities has a real incentive to build a reclaimed water project that augments existing sources and reduces discharge. Broader in scope, the National Environmental Policy Act (NEPA) requires an assessment of environmental impacts for all projects receiving federal funds, and then the mitigation of all significant impacts. Many states also have equivalent rules that mandate environmental assessment and mitigation planning for all projects prior to construction. Combined with other laws that protect biological, scenic, and cultural resources, these laws can result in a de facto moratorium on the construction of large-scale water diversions (by dams) that flood the habitat of protected species or inundate pristine canyons or areas of historical significance. Even where such projects are allowed to go forward, they may be less cost-effective than water reuse projects that provide a comparable supply with fewer and less expensive mitigations. Both federal and state environmental assessment regulations generally require an economic analysis of alternatives, including the “no project” alternative in which nothing is built. A number of guidance documents are available suggesting approaches to evaluating both the costs and benefits of water projects, including water reuse alternatives. It is par-


developed and periodically revised, including lengthy review procedures, the timing of any public hearings that must be held, and the time needed to enact any required legislation. It is especially important to identify any permit review procedures and whether they can occur concurrently or must occur consecutively, and in what order. Special Environmental Topics

resents a clear benefit to the neighborhoods where it is available, the population at large does not always share this view. The project manager of a water reuse program should discuss project plans with representatives from all affected communities to gauge their sensitivity to this issue, and provide additional information about reclaimed water to help alleviate neighborhood concerns.

In addition to the assessment of environmental impacts commonly encountered by construction of all types of water projects, there are some topics of special concern for the evaluation of reuse projects that reflect the safety of reclaimed water use, including growth inducement, environmental justice, and detection of emerging pathogens. Because the project proponent or lead agency must, by law, address all material questions raised during the assessment process, these topics should be considered at some point during project planning—if only to note that they do not apply. One environmental impact associated with reclaimed water projects is the potential for growth inducement. Indeed, where communities are constrained by a limited water supply, the availability of a reliable source of reclaimed water can allow more growth than might otherwise occur. However, there are many other factors that contribute to the increase in population in an area, and substitution of nonpotable for potable water may only reduce the negative impact a community’s existing water use has on the neighboring environment. In any case, the question of growth inducement must be addressed in evaluating the overall impact of reclaimed water projects. The question of environmental justice may come up during the permitting of water reuse projects. The term “environmental justice” refers to the historic pattern of siting undesirable environmental facilities (e.g. wastewater treatment plants, landfills and transfer stations, solid waste incinerators) in or adjacent to economically depressed neighborhoods, whose populations may have a proportionally large percentage of people of color or ethnic minorities. An environmental justice policy attempts to ensure that all such facilities are distributed equally throughout the community, so that no one segment bears a disproportionate share of the impact. This policy is reinforced by a number of federal rules pertaining to environmental review of federally-funded projects, the ultimate source of which is the constitutional right to equal protection under the law. While it is reasonable to argue that reclaimed water distribution facilities should not be grouped with other more noxious facilities, and that the use of reclaimed water rep-


Legal Issues in Implementation

Just as there are many laws and policies that influence the planning and overall design of water reuse projects, their detailed design, construction, and implementation is also governed by a number of rules and regulations. For example, state health departments may require minimum setback distances between potable and nonpotable pipelines (addressed in Chapter 4), while dual distribution facilities at the customer’s site may have to be constructed to meet Uniform Plumbing Code standards. Similarly, a value engineering study of the system design may need to be performed in order for the project to qualify for state or federal funding, which may add to the time required for project review and impact the ultimate construction schedule. Following construction, various parties need to coordinate their efforts to produce, distribute, deliver, and pay for reclaimed water. Each of these parties must be organized to comply with their contractual obligation, with appropriate legal agreements between the parties to clearly spell out and enforce responsibilities. Indeed, there are a range of legal agreements that may be necessary in order for reclaimed water to be delivered to the end customer for reuse. The following section examines laws and regulations pertaining to project construction (both system wide and on-site), agreements between water wholesalers and retailers, and customer agreements to ensure payment and proper handling of reclaimed water by the end user.


Construction Issues

In general, there are 2 types of regulations associated with construction of reuse projects: 1) Rules governing system construction, including large-diameter mains, pump stations, reservoirs, and other appurtenances required to deliver reclaimed water to groups of customers 2) Rules for on-site construction, specifically separation of existing pipelines into potable and


nonpotable systems, or the installation of new reclaimed water pipelines separate from the potable system As noted in Chapter 4, state health departments often promulgate regulations for both system and on-site construction, but these rules may be administered by county or even local health departments. State agencies may also take the lead in ensuring that project designs meet the requirements for grant funding, but their rules are frequently adopted from existing federal grant or loan programs. Local agencies may adopt their own special rules incorporating state regulations with additional requirements specific to local jurisdictions. System Construction Issues


Formal review of all designs to ensure that they meet professional standards and present the most “cost-effective” solutions to engineering problems. This review often includes value engineering of the project by professionals who were not involved in the original design. Institution of a revenue program identifying additional sources of funds to pay for the initial construction. This is especially true when grant funds are provided for construction on a reimbursement basis, to ensure that the project sponsor will be able to afford the project without the support of grant funds. they will individually and collectively use a specific quantity of reclaimed water once it is supplied.


„ Identification of customers, with some evidence that

Chapter 4 includes a detailed analysis of water reuse regulations and design guidelines in various states. These issues are included here only to provide a comprehensive picture of the overall legal context in which reuse projects are developed and built. Regulations impacting system construction include both rules governing utility construction in general and rules specifically aimed at water reuse projects. Regulations governing general utility construction include requirements to observe and maintain proper easements for pipelines and facilities, local codes with respect to acceptable building materials and construction practices, as well as all applicable contract and labor laws (which is beyond the scope of this chapter). Prior to and during design of any system construction project, the project manager should become familiar with state and local construction regulations and obtain all necessary permits from local agencies, utilities, and other parties so as not to delay project construction. In addition to these general rules, many states have rules specifically pertaining to the construction of reclaimed water systems. These regulations frequently designate physical separation distances between reclaimed water and potable and wastewater lines, as well as details for pipeline crossings (e.g., nonpotable below potable). Where it is not practical to maintain minimum distances, some states allow construction of nonpotable pipelines adjacent to potable lines provided that they are cased in suitable materials. From a legal perspective, federal and state grant and loan programs are established by statute and often establish construction-related rules that projects must meet to qualify for funding. Typically these include:

Early in the process, agencies that accept grants or loans should be aware of the requirements of their particular programs with respect to project design and funding. On-site Construction Issues

Like system construction regulations, standards for constructing distribution pipelines on a customer’s site (e.g. irrigation systems) are usually a combination of state regulations and local ordinances specifically regarding the use of reclaimed water. State regulations generally focus on requirements to prevent accidental or intentional cross-connection of potable and nonpotable systems by separating the pipelines, requiring clear identification of nonpotable facilities, and installing backflow prevention devices, where appropriate. Local agencies may adopt individual regulations by ordinance, or they may adopt general regulations like the Uniform Plumbing Code, whose Appendix J includes special rules for installing reclaimed water lines inside buildings where potable water is also served. Once again, the manager of a reuse project should become familiar with all pertinent regulations during the design phase to ensure that the system meets state and local codes. See Chapter 4 for a detailed discussion of regulations that have been adopted in various jurisdictions throughout the U.S. Once on-site facilities have been constructed, state and local regulations often require that cross-connection tests be performed to ensure complete separation between potable and nonpotable systems. Depending on the quality of the water provided and the type of use, agencies may also restrict the times of use and require periodic inspection and reporting on system operation, even after the on-site system has been installed and


approved. This topic is addressed more closely in Section 5.5.3 Customer Agreements.


Wholesaler/Retailer Issues

Los Angeles County, which sells reclaimed water to several purveyors, including the municipal Pomona Water Department, who then redistributes it to a number of users. Institutional Criteria

One of the first steps in implementing a water reuse program is the identification of roles and responsibilities for the production and wholesale and retail distribution of reclaimed water. Many different types of institutional structures can be utilized for implementing a water reuse project and responsibility for reclaimed water production and wholesale and retail distribution can be assigned to different groups depending on their historical roles and technical and managerial expertise (Table 5-1). The various departments and agencies within a government may come into conflict over the proposed reuse system unless steps are taken early in the planning stages to find out who will be involved and to what level. Close internal coordination between departments and branches of local government will be required to ensure a successful reuse program. Obtaining the support of other departments will help to minimize delays caused by interdepartmental conflicts. A good example of integrated authority is the Irvine Ranch Water District in California, an independent, selffinancing entity responsible for all phases of reclaimed water production and distribution. Under its original enabling legislation, the district was strictly a water supply entity; but in 1965, state law was amended to assign it sanitation responsibilities within its service area. This put the district is in a good position to deal directly, as one entity, with conventional potable water and nonpotable water services. Such a position contrasts markedly with other institutional arrangements in the Los Angeles area, where agency relationships are often more complex. For instance, the Pomona Water Reclamation Plant is operated by the Sanitation Districts of Table 5-1. Some Common Institutional Patterns

In evaluating alternative institutional arrangements, responsible managers should determine the best municipal organizations or departments to operate a reclamation and reuse program. For example, even if the municipal wastewater treatment service is permitted by law to distribute reclaimed water, it might make more sense to organize a reuse system under the water supply agency or under a regional authority (assuming that such an authority can be established under the law). Among the criteria that should be considered in developing a viable arrangement is the ability of the proposed entity to finance the project and enter into the following types of agreements:

Financing Power – The agency responsible for financing the project should be able to assume bonded indebtedness, if such financing is likely, a determination should be made as to what kind of debt could be assumed, how much, and how debt must be retired. In addition, the evaluation should include the method for recovering the costs of operating the water reclamation facility and any restrictions placed on them by virtue of the institutional structure, including kinds of accounting practices to be imposed upon the entity. Contracting Power – Any constraints on how and with whom services can be contracted should be identified, as well as the method of approving such agreements. For example, if contracts are required with other municipalities, they may have limitations on the nature of the corporate structure or legal au-


Type of Institutional Arrangement Separate Authorities Wholesaler/Retailer System Joint Powers Authority (for Production and Distribution only) Integrated Production and Distribution

Production Wastewater Treatment Agency Wastewater Treatment Agency Joint Powers Authority Water/Wastewater Authority

W holesale Distribution Wholesale Water Agency Wastewater Treatment Agency Joint Powers Authority Water/Wastewater Authority

Retail Distribution Retail Water Company Retail Water Company Retail Water Company Water/Wastewater Authority


thorization of entities with whom they enter into agreement. Institutional Inventory and Assessment

It is necessary to develop a thorough understanding of which organizations and institutions are concerned with which aspects of a proposed reuse system. This understanding should include an inventory of required permits and agency review requirements prior to construction and operation of the reuse system, economic arrangements, subsidies, groundwater and surface water management policies, and administrative guidelines and issues. The following institutions should be involved or at a minimum, contacted: federal and state/regulatory agencies, administrative and operating organizations, and general units of government. On occasion there is an overlap of agency jurisdiction. For example, it is possible for one agency to control the water in the upper reaches of a stream and a separate agency to control the water in the lower reaches. Unless these agencies can work together, there may be little hope of a successful project. One of the best ways to gain the support of other agencies is to make sure that they are involved from the beginning of the project and are kept informed as the project progresses. Any potential conflicts between these agencies should be identified as soon as possible. Clarification on which direction the lead agency should follow will need to be determined. By doing this in the planning stages of the reuse project, delays in implementation may be avoided.

appropriate regard for public health. In fact, the agency responsible for reclaimed water distribution should consider adopting an ordinance requiring customers to meet these standards of performance as a condition of receiving reclaimed water. Or, if that is not appropriate, the agency should encourage the jurisdictions where the customers are located to pass such ordinances. In some cases, the requirements for customer performance have been delegated by the state to the reclaimed water purveyor, who in turn is empowered to delegate them to their customers. For instance, where reclaimed water is still statutorily considered effluent, the agency’s permit to discharge wastewater may be delegated by the agency to customers whose reuse sites are legally considered to be distributed outfalls of the reclaimed water, with concomitant responsibilities. The second group of agreements, those agreements made between parties, are more variable and reflect the specific circumstances of the individual projects and the customers they serve. These include rates and charges, fees, rebates, terms of service, and other special conditions of use between reclaimed water suppliers and customers. Not all reclaimed water systems require development of a reclaimed water ordinance. This is particularly true where there are a limited number of users. For example, it is not uncommon for a reclaimed water supplier providing service to a small number of large users, such as agriculture or industrial customers, to forego development of a reuse ordinance and rely instead on user agreements. In other instances, such as water intensive activities, a single user may well encumber all of the water available from a given reclaimed water source. Where such conditions exist, it is often more appropriate to deal with the customer through the negotiation of a reclaimed water user agreement. However, all of the customer issues discussed should still be addressed in developing customer agreements. Statutory Customer Responsibilities


Customer Issues

Finally, a key link in the chain of institutional arrangements required to implement water reclamation projects is the relationship between the water purveyor and the water customer. Again, there are 2 dimensions to this arrangement: 1) The legal requirements established by state and local jurisdictions defining the general responsibilities of the 2 parties to protect the public 2) The specific items of agreement between the parties, including commercial arrangements and operational responsibilities The legal requirements are usually stipulated in state laws, agency guidelines, and local ordinances designed to ensure that reclaimed water is used safely and with

Protective measures are required to avoid cross-connection of reclaimed water lines with potable water lines. In the event that these responsibilities are codified in a local ordinance, the ordinance and its provisions should be clearly spelled out in the customer agreement. (Local ordinances may, in turn, reference state regulations on this subject, in which case they should provide specific citations, in addition to general references, for the sake of clarity.) As noted in Chapter 4, required protections may include the mandatory backflow preventers, use of color-coded


pipes for the reclaimed and potable water, and periodic inspection of the system. Inspection is recommended to determine if there are any illegal connections, violations of ordinances, or cross-connections. It is important that the ordinance or agreement state which party is responsible for inspection, under what conditions and with what frequency inspection may be required, as well as the consequences if users refuse to perform or allow inspection (i.e., disconnection of service). A customer agreement (or the corresponding local ordinance) might also specify the type of irrigation system required in order to receive reclaimed water. This could include the requirements for system design (e.g., a permanent below-ground system) or construction details (e.g., specific pipe materials or appurtenances like quick disconnect fittings on hose bibs used for hand watering). The requirements for an irrigation system timer may also be included. The customer agreement may also include details on financing on-site construction to separate potable and nonpotable piping systems. It is not uncommon for local agencies to fund all or part of the cost of retrofitting a customer’s existing system in order to defray the overall cost of reclaimed water use. In such instances, the agency may provide grant funds to the customer to cover the cost of construction or may even construct the facilities at the agency’s expense after obtaining a rightof-entry from the customer. In other cases, the cost of the construction may be covered by reductions in the normal rates over a period of time. Although not included in a customer agreement, a local ordinance might also define when property owners will be required to connect to the reuse system. Examples include the requirement for turf grass facilities (e.g., parks, golf courses, cemeteries, schools) to connect when the system becomes available, requirements for new developments to connect prior to being inhabited, and requirements for all properties to connect as the reuse system becomes available. These agreements might also specify what equipment is available to the customer and how it can be used. For example, Florida allows hose bibs on the reclaimed water system but they must be placed in below-ground, locking boxes. Local ordinances may also contain requirements for public education about the reuse project, including information on the hazards of reclaimed water, the requirements for service, the accepted uses, and the penalties for violation. In Cocoa Beach, Florida, reclaimed water applicants must be provided an informative brochure to explain public safety and reuse in accordance with the

City’s ordinance. A detailed discussion of public information programs is provided in Chapter 7. Terms of Service and Commercial Arrangements

Any reclaimed water connection fees and rates associated with service should be addressed in an appropriate rate ordinance passed by the local jurisdiction. Reclaimed water rate ordinances should be separate from those regulations that control reclaimed water use, and may include an “escalator clause” or other means of providing for regular increases proportional to the cost of potable water in the local area. (See Chapter 6 for a discussion of the development of the financial aspects of water reuse fees and rates). In addition to these considerations, it is often helpful to establish various other terms of service that are particular to the water reuse program and its customers. For example, the customer agreement may specify a certain level of reliability that may or may not be comparable to that of the potable system. When reclaimed water is used for an essential service, such as fire protection, a high degree of system reliability must be provided. However, if reclaimed water use is limited to irrigation, periodic shortages or service interruption may be tolerable. The reclaimed water supplier may also wish to retain the right to impose water use scheduling as a means of managing shortages or controlling peak system demands.


Case Studies
Statutory Mandate to Utilize Reclaimed Water: California

Underscoring the fact that potable water resources are strained and in many cases reclaimed water represents the next best supply, some states have integrated reclaimed water into the codes and policies that govern water resources in general. An example of such a case from California is Article 7, Water Reuse from the California Code of Regulations, Section 13550, Legislative Findings and Declarations; Use of Potable Water for Nonpotable Uses Prohibited. a) The Legislature hereby finds and declares that the use of potable domestic water for nonpotable uses, including, but not limited to, cemeteries, golf courses, parks, highway landscaped areas, and industrial and irrigation uses, is a waste or an unreasonable use of the water within the meaning of Section 2 of Article X of the California Constitution


if reclaimed water is available which meets all of the following conditions, as determined by the state board, after notice to any person or entity who may
be ordered to use reclaimed water or to cease using potable water and a hearing held pursuant to Article 2 (commencing with Section 648) of Chapter 1.5 of Division 3 of Title 23 of the California Code of Regulations:

son subject to this article to furnish information, which the state board determines to be relevant to making the determination required in subdivision (a).

(1) The source of reclaimed water is of adequate quality for these uses and is available for these uses. In determining adequate quality, the state board shall consider all relevant factors, including, but not limited to, food and employee safety, and level and types of specific constituents in the reclaimed water affecting these uses, on a user-by-user basis. In addition, the state board shall consider the effect of the use of reclaimed water in lieu of potable water on the generation of hazardous waste and on the quality of wastewater discharges subject to regional, state, or federal permits. (2) The reclaimed water may be furnished for these uses at a reasonable cost to the user. In determining reasonable cost, the state board shall consider all relevant factors, including, but not limited to, the present and projected costs of supplying, delivering, and treating potable domestic water for these uses and the present and projected costs of supplying and delivering reclaimed water for these uses, and shall find that the cost of supplying the treated reclaimed water is comparable to, or less than, the cost of supplying potable domestic water. (3) After concurrence with the State Department of Health Services, the use of reclaimed water from the proposed source will not be detrimental to public health. (4) The use of reclaimed water for these uses will not adversely affect downstream water rights, will not degrade water quality, and is determined not to be injurious to plant life, fish, and wildlife.
In making the determination pursuant to subdivision (a), the state board shall consider the impact of the cost and quality of the nonpotable water on each individual user.

HISTORY: Added by Stats.1977, c. 1032, p. 3090, Section 1, eff. Sept. 23, 1977. Amended by Stats.1978, c. 380, p. 1205, Section 148; Stats.1978, c. 894, p. 2821, Section 1, eff. Sept. 20, 1978; Stats.1991, c. 553 (A.B.174), Section 1.


Administrative Order to Evaluate Feasibility of Water Reclamation: Fallbrook Sanitary District, Fallbrook, California

In 1984 the California State Water Resources Control Board considered a complaint filed by the Sierra Club to enjoin an unreasonable use of water by a wastewater discharger (California State Water Resources Control Board Order 84-7). At issue was a permit issued by the Board authorizing the Fallbrook Sanitary District to discharge up to 1.6 mgd (6000 m3/d) of treated wastewater to the ocean. The Sierra Club alleged that under the circumstances, the discharge of the district’s wastewater to the ocean, where it cannot be recovered for beneficial use, constitutes a waste of water. Before a wastewater discharger can be required to reclaim water, a determination must be made whether the particular discharge constitutes a waste or unreasonable use of water. Water Code Section 13550, with its focus on prohibiting the use of potable water for nonpotable applications, provided no guidance to the State Board in this instance. Thus, in making its determination, the State Board sought guidance from the state’s constitutional prohibitions on waste and related case law. In keeping with the case law, which indicates that a reasonable use of water today may be a waste of water at some time in the future, the State Board ordered the district, and all future applicants proposing a discharge of once-used water into the ocean, to evaluate the feasibility of reclaiming its wastewater. The State Board insisted that water reclamation be carefully analyzed as an alternative, or partial alternative, to the discharge of once-used wastewater to the ocean in all water-short areas of the state. In adopting its order, the State Board recognized the requirements were consistent with the Board’s authority to conduct investigations and prevent

c) The state board may require a public agency or per-


waste of water (California Water Code). Information provided by Cologne and Maclaggan (1995) “Legal Aspects of Water Reclamation” in Wastewater Reclamation and Reuse.

the city boundaries. Clearly there are other examples of the need for a user agreement when dealing with a larger customer. Orange County, Florida, provides over 10 mgd (438 l/s) of make-up water from its water reclamation facility to the Curtis Stanton Energy Center. The Curtis Stanton Energy Center, located on the east side of Orlando, is owned by the Orlando Utilities Commission and provides electric power to the greater Orlando area. There are unique aspects to the relationship between these 2 entities with respect to the supply of reclaimed water for cooling purposes including stringent water quality requirements, delivery schedules, fees, and means for handling the blow-down water.


Reclaimed Water User Agreements Instead of Ordinance: Central Florida

While most reclaimed water systems with multiple users will require the adoption of a reclaimed water ordinance, there may be cases where an ordinance is not required, particularly when there are a limited number of users in the system. An example would include the provision of reclaimed water to several large agricultural users where the need for control extends to only a few parties. In such cases, it may be entirely appropriate to handle the requirements of the supplier and the users through a user agreement. Orlando, Florida’s reclaimed water program (in concert with Orange County, Florida) began with about 20 citrus growers under the Water Conserv II Irrigation Program in 1986. Orlando/Orange County entered into a 20-year agreement with each of the growers, with the agreement specifying the responsibilities of both the supplier and the user. Each of these agreements was identical except for the volume of flow provision. The agreement covered suppliers’ contractual requirements including “no cost” provision of reclaimed water, water quality limits, minimum pressures, volume of water and delivery schedules, and indemnity provisions for third party claims. From the users’ side, the agreements addressed issues such as requirements to take a certain volume of water, transfer of land allowances, inspection requirements, and buyout provisions if the agreement was terminated prior to the 20 year term. As Orlando’s reclaimed system grew, each of the users, either agricultural or commercial, were required to enter into a user agreement. For the commercial users, an agreement was developed similar in some respects to the grower agreement. These commercial agreements evolved over time, but all contained the same basic requirements. For example, each of them stated that the customer would pay the user fee for the reclaimed water when such a rate was established by the City. It was not until 2002 that the City elected to adopt monthly user rates with the growth of the reclaimed system for single-family residences. These rates were implemented shortly after the adoption of a reclaimed water ordinance, which governs all aspects of the reclaimed water system within


Interagency Agreement Required for Water Reuse: Monterey County Water Recycling Project, Monterey, California

The Monterey County Water Recycling Project (MCWRP) consists of a tertiary water recycling plant and water distribution system. Since beginning operation in the spring of 1998, over 14 billion gallons (53 million m3) of reclaimed water have been produced for irrigation of food crops such as artichokes, lettuce, cauliflower, celery, and strawberries. The project was designed to reduce seawater intrusion along the northwest portion of Monterey County (California) by using reclaimed water instead of groundwater. The reclaimed water is supplied by the regional wastewater provider, the Monterey Regional Water Pollution Control Agency (MRWPCA). However, the responsibility for water planning rests with the Monterey County Water Resources Agency (MCWRA). Thus, 2 types of agreements were required. The first was a contract between MRWPCA and MCWRA for the sale, disposition, and operation of MCWRP. The second was a series of ordinances between MCWRA and the growers that governed the providing of water for the end user. The focus of this case study is on the contract between MRWPCA and MCWRA. The base agreement was signed in 1992 and contained the following key provisions: A. Project Ownership, Operation, and Maintenance

The project will be owned and operated by MRWPCA MRWPCA will be reimbursed for the actual



cost of its operation

MRWPCA will supply water on a daily basis except for infrequent shut-downs Water will be provided in accordance with a specified demand schedule

Reuse Program: The City of Orlando, Orange County And The Private Sector – Orlando, Florida
The Orange County National Golf Center (OCNGC) is a unique and innovative public/private partnership formed by Orange County, the City of Orlando, and Team Classic Golf Services, Inc. The Orange County National is one of the largest golf centers in the State of Florida, devoted solely to golf and golf instruction. The Orange County National Golf Course project represents an expansion of the successful Conserv II reuse program jointly owned and operated by the City of Orlando and Orange County, Florida. (See the case study, 3.8.6 Water Conserv II Chapter 3 for additional details.) The County and City purchased 660 acres (270 hectares) of additional land adjacent to 2 of its original rapid infiltration basins (RIB) sites in the rolling hills of west Orange County, originally intended solely for the construction of new RIBs. Large RIB sites in this area typically consist of a series of basins interspersed across the site with large areas of open land between them. In fact, RIBs typically occupy as little as 15 percent of the site, with the remaining area being available for other uses. Hoping to achieve multiple uses on the new lands, the County commissioned a study to determine the feasibility of building a municipal golf course. The results of the feasibility study were very encouraging, and the County and City agreed to pursue this option with the County acting as the lead-contracting agency. During a subsequent regulatory and permitting delay in the RIB expansion program, an internationally renowned golf instructor and course developer, Mr. Phil Ritson, approached the Orange County Parks Department and the Orange County Convention Center in search of land to construct a public golf course. After considerable debate, all parties agreed to investigate the feasibility of co-locating RIBs and golf facilities on Conserv II property owned jointly by the City and County. Project planning for the golf course began in 1991. Using a four-step process, the team completed the following before construction started: (1) a business feasibility plan; (2) a request for interested golf course developers; (3) a leasehold agreement; and (4) a capital-financing plan. Each step was crucial and built on the work of the previous steps. The business feasibility study showed excess demand for golf and high potential for a golf course development. This analysis, along with the primary environmental concerns, such as protection of on-site wetlands


B. Maintenance of Water Quality

Water produced will be suitable for irrigation of food crops MRWPCA will monitor water quality cal growers, will be formed


„ Water Quality Committee, which includes lo-

C. Records and Audits

Accounting system required that allocates project costs Annual project audit required


D. Project Repairs and Maintenance
„ „

Reserve for replacement established MCWRA will cover uninsured costs

E. Indemnification and Insurance

Each party will hold each other harmless from damages and amounts of project insurance are defined

„ Types

F. Term of Agreement/Dispute Resolution

Provisions for extension of the Agreement are defined Options to cancel/terminate are described Requirement to meet and confer in the case of disputes

„ „

Three amendments to the agreement have been negotiated in order to clarify the details of the agreement. Overall, this contract has worked well.


Public/Private Partnership to Expand


acreage and a preliminary survey of threatened and endangered species, was used to develop a request for business proposals. In September 1993, after the City and County had selected and approved Team Classic Golf Services, Inc. as a partner, the difficult work began – negotiating terms for the long-term lease, securing financing for the deal, and setting up a team which would work to the mutual benefit of all the partners. The major breakthrough in the project came when Team Classic acquired private sector financing totaling $51.5 million. A public/private partnership was established through a 55 year leasehold agreement. Forming a partnership with the municipal government and private sector parties took 6 years from its conceptual and planning stages until the start of construction. In addition to RIBs, the OCNGC incorporated several other environmental benefits. The site includes a number of isolated wetland areas that had been degraded through lowered water tables and invasion of undesirable plant species. The combined golf course RIB and surface water management system was designed to restore and maintain more desirable water elevations, and the invading plant species were removed and replaced by hand-planted native species appropriate to the wetland type. The site was developed in a low-density layout, leaving natural upland habitat areas between the golf holes. Today, 54 holes of golf are open along with a 42-acre (17-hectare) practice range and a 9-hole executive course. The facilities also include a 33,000 square-foot (3,070- m2) clubhouse, 50-room campus lodge, a Pro Studio with 5,000 square feet (465 m2) of instructional space, and an institute housing classrooms and administrative offices. It is estimated that private sector investment will exceed $100M at completion. Accessibility has been increased through a multi-tiered fee structure that provides reduced rates to Florida residents and even greater reductions for Orlando and Orange County residents. Rent is paid to the City and County in tiered lease payments tied to time and financial performance of the golf course development. As the golf center is more successful, the lease payments will increase. University of Florida Institute of Food and Agricultural Sciences (IFAS) is using the site as part of a study, which is co-funded by the County and City. The study is examining the effects of reclaimed water use on golf courses, including the effects of fertilizer and pesticide applications. The study results are being used to develop best management practices for golf courses irrigated with reclaimed water.


Inspection of Reclaimed Water Connections Protect Potable Water Supply: Pinellas County Utilities, Florida

Few things are more important than a safe, potable water supply. Therefore, cross connection control must be taken seriously and comprehensive inspections are absolutely necessary to ensure the public’s health. In addition, state and local ordinances and policies must be thoroughly and uniformly enforced. This has become even more important considering the potential threats to our drinking water. Pinellas County, Florida, began its Cross Connection Control and Backflow Prevention Program in 1977. Major improvements to the inspection process were implemented in 1994 and 2002. Inspections have uncovered remote hose bibs (to docks, etc.), hidden and/or forgotten valves, and interconnections between the potable and well systems with inexpensive and leaking ball or gate valves. Pinellas County requires that the reclaimed water connection remain in the locked position and that the irrigation system be separated until the day of inspection. The owner, or their legal representative, must sign an application (see copy following this case study) agreeing to use the reclaimed water for its intended purpose and agreeing to inform future owners of these conditions. Owners must schedule an inspection and are to be present to operate the entire system. First, the inspector verifies that the backflow prevention device is installed on the potable meter. Pinellas County inspectors check all zones for potential cross-connections and overspray into public waters, sidewalks, and roadways. A “dry” run, with the potable source on and the reclaimed source off, is then conducted. This helps to limit the possibility of reclaimed water entering the building. Certainly, it is far less intrusive and more cost-effective than flushing the potable plumbing system if a cross-connection occurs. Then the “wet” run, with the reclaimed water connected and the potable water supply turned off at the meter, begins. This uncovers any remote connections and any cross-connections under the reclaimed pressure. A 1-page report (see copy following this case study) with a “point of disconnect” (POD) sketch is completed by the inspector. A reclaimed water curb marker is glued to the curb indicating that the property has passed the inspection. This information is then entered into a database. Initially, contractors who are unfamiliar with this process have minor concerns about the length of time for this inspection. A typical, well-prepared residential property



1. The Pinellas County Utilities Inspector briefly explains the inspection procedure. 2. The Inspector asks the questions necessary to complete the Reclaimed Water Cross-Connection Inspection form, and records the information on the form. 3. The Inspector checks to see if the reclaimed service line has been connected to the irrigation system and checks to make sure that the reclaimed service valve is locked off. 4. The Inspector walks around the building, checking to make sure that all hose bibbs have water flowing from them, and to see if a pressure relief valve is attached, that all reclaimed valve box covers and exposed pipes located above ground (except risers for bush spray heads) are purple in color from the factory or painted with Pantone Purple 522C (Florida Building Code - Plumbing 608.8; DEP 62-610.469(7)(f)) using light stable colorants, and that all sprinkler heads are attached. 5. The Inspector asks to see the Point of Disconnect (POD) from the potable, well, or other water source. 6. The Inspector starts the Dry Run by having the Contractor or Homeowner operate each of the solenoid valves, one zone at a time, and then checks to see if any other water source is being used for irrigation. 7. The Inspector asks the Contractor or Homeowner to connect the irrigation system to the reclaimed service line, and then unlocks the reclaimed water service valve. 8. The Inspector starts the Wet Run, by opening all hose bibbs and then closing the potable water at the water meter and letting the hose bibbs completely drain. Next, the reclaimed water service valve and the Homeowner’s shut-off valve are opened, and each irrigation zone on the property is run, one zone at a time. When each zone is fully pressurized, the Inspector checks each hose bibb to make sure no water is coming out of them and also checks for over spray. 9. The Inspector turns the potable water back on and then turns off all of the hose bibbs. 10. The Inspector installs a Reclaimed Water curb marker on the curb or road edge. 11. The Inspector makes a drawing on the form, depicting the locations of buildings, streets, driveways, sidewalks, POD, Pinellas County water meter, and the reclaimed box. Any areas with no irrigation present are identified, and each component of the drawing is labeled. The location of the POD is referenced by measurements taken at right angles to the building’s walls. 12. The Inspector returns to the office and enters the information into the MAXIMO Work Management computer program.


Pinellas County Application for Reclaimed Water Service and Cross-Connection Inspection Forms As reclaimed water service becomes more common, utilities create the forms required to keep track of customers and address concerns critical to distribution of nonpotable water. The following forms present the application for service and cross-connection inspection forms currently used by the Pinellas County Utilities in Florida.


Owner’s Full Name and Service Address Please Print in Ink

Mailing Address (If different than service address) Please Print in Ink


inspection is completed in 45 to 60 minutes. Approximately 8,000 inspections have been conducted and contractors work successfully with the County’s experienced inspectors. Information provided by the Pinellas County Utilities Department – Cross-Connection Control and Backflow Prevention Program, 1998, Clearwater, Florida.


Oneida Indian Nation/Municipal/ State Coordination Leads to Effluent Reuse: Oneida Nation, New York

the conservation of existing potable water supplies, and reduced pollutant loads into Oneida Creek and, ultimately, Oneida Lake, which is part of the Great Lakes watershed. The Nation also made its position clear that the NYSDEC had no jurisdiction over activities on Nation land. The NYSDEC concurred with the Nation and City’s reclaimed project concept plan, and expressed its basic support of the project. It outlined for the Nation and the City the regulatory framework and procedural steps for expediting the project. To formally commit the City to the project, the City Council and Mayor needed to pass a resolution to authorize the technical staff of its Public Works Department to proceed with the project. The project team elected to use one of the City’s semi-monthly council meetings as the forum to present the benefits of the project. Informational fact sheets were prepared for the meeting, which described in simple terms what reclaimed water is, the current uses of reclaimed water by other communities, and the environmental benefits of reclaiming highly treated wastewater. The fact sheets were distributed before the meeting so that elected officials, the public, and the news media could prepare questions before the council meeting. Factual and candid information was presented on water reclamation – its need in the overall growth plans of the Nation, its environmental benefits and, through its use, the conservation of limited potable water supplies. The City Council unanimously approved a resolution pledging the City’s support and commitment to cooperate with the Nation on this project. The implementation phase of the project included the following major milestones:
„ Preparing a draft reuse agreement between the Na-

The Oneida Indian Nation is in a period of strong economic growth. The cornerstone of its economic development is the Turning Stone Casino Resort, the only casino in New York State. The casino and other Nation enterprises are located in an area of central New York with limited water resources. The viability of future enterprise development is linked to the Nation’s ability to adequately meet its water supply and wastewater treatment needs. For the Nation’s planned golf course complex, reclaimed water has been identified as a viable water resource for irrigation water. Implementing water reclamation required inter-governmental cooperation between the Nation and the reclaimed water supplier, the City of Oneida. Regulatory or jurisdictional cooperation between the New York State Department of Environmental Conservation (NYSDEC) and the Nation also was required because the Nation, being sovereign, is free to establish its own environmental standards for its lands, while the City is regulated by the NYSDEC. The project was further complicated by the fact that the NYSDEC does not have reclaimed water quality or treatment standards for unrestricted reuse. An estimate of the peak irrigation demand for the Nation’s proposed golf course complex is 670,000 gpd (2540 m3/d), which is well in excess of the potable water allocation available to the Nation (150,000-250,000 gpd, 570-950 m3/d). Investigation of the area’s water resources identified the City of Oneida’s wastewater treatment plant as a water source. The City subsequently agreed to support the Nation’s concept for a water reclamation project. Reclaimed water use is not a common practice in New York State. In fact, the state does not have reclaimed water quality or treatment standards for either restricted or unrestricted urban reuse. In the initial stages of the project, a stakeholders meeting was held with representatives of the Nation, the City, and the NYSDEC. The environmental benefits of the project were discussed at this meeting – the reuse of a water resource,

tion and the City
„ Completing the State Environmental Quality Review

(SEQR) process to demonstrate the project’s environmental benefits and lack of significant negative impacts

Obtaining approval from the NYSDEC for a State Pollutant Discharge Elimination System (SPDES) permit modification to allow the city to deliver its treated water to the Nation’s irrigation pond Completing a preliminary design of the project.


Each of these project aspects is discussed below: Reuse Agreement – The agreement addresses reclaimed water quality and characteristics. The City of Oneida will be responsible for delivering to the Nation


reclaimed water of sufficient quality to meet the requirements of the City’s SPDES permit and target water quality conditions identified in the reuse agreement. While the entire cost of constructing the project will be borne by the Nation, the planned treatment and pumping systems will be installed at the City’s wastewater treatment plant site. The City will be responsible for operating the reclaimed water system. As needed, the Nation will contract with a third party for major maintenance and repair work for the facilities and pipeline. Other provisions of the agreement include easement and usage rights to allow the City access to Nation land to operate and monitor the reclaimed system, standard conditions regarding good faith commitments, a limited waiver of sovereign immunity for the purpose of implementing and enforcing the agreement, indemnification, notices, and amendments and assignments. SEQR Review Process – The first step in the SEQR process was for the City to formally request “lead agency” status. This required sending a letter of notice, along with a basic project description, to the potentially interested agencies (including NYSDEC, County Departments of Health, EPA, Army Corps of Engineers, and New York State Department of Transportation). After a required 30-day public comment period, during which no other agency challenged the City’s lead agency request, the City became lead agency for SEQR purposes. An environmental assessment of the project was completed and resulted in a recommendation to the City Council that a “negative declaration” (akin to the ”finding of no significant impact” under NEPA) be declared. As an “unlisted action,” the project’s SEQR conclusion did not need any additional public comment period after the City’s negative declaration. SPDES Permit Modification – To deliver water to an outfall location other than its permitted discharge point (Oneida Creek), the NYSDEC required that the City complete a SPDES permit modification request. Currently, the permit application is under review by the NYSDEC. It is anticipated that the City will obtain the permit modification with few exceptions to the proposed plan. Early involvement and open communication with the NYSDEC was a key success factor in preparing the application based on specific guidance form the NYSDEC. Preliminary Design – The design report addressed the preliminary design criteria and basis of design for the needed reclaimed water system components, including operation and control strategies. The system design includes a provision that would allow the City to process

a portion of its secondary treated effluent through the reclaimed system filter (i.e., providing tertiary treatment) for discharge to the creek outfall in the event there is no demand for reclaimed water. This provision would allow the City to discharge a higher quality water to the creek, but it would not obligate the City to provide a higher level of treatment than is now required by its existing permit. This provision is a secondary benefit, not the driving force behind the project or future permit requirements. In New York State, where water reclamation is not commonly practiced, the Nation, the City of Oneida, the NYSDEC and other local agencies collaborated in an inter-governmental and multi-jurisdictional effort to make this project possible. A key reason for the successful collaboration was effective communication among all project stakeholders. All involved parties shared the conviction that the project was a win-win proposition for the Nation, the City, and the environment. Early, twoway communication that consistently focused on the project’s benefits resulted in full and unanimous support of the project at each of the legal decision-making junctions.


Implementing Massachusetts’ First Golf Course Irrigation System Utilizing Reclaimed Water: Yarmouth, Massachusetts

For the first time in the Commonwealth of Massachusetts, reclaimed water is being used as the source water to irrigate a golf course – The Links at Bayberry Hills, which is owned and operated by the Town of Yarmouth. This project required a team effort on the part of everyone involved and many years to successfully implement. The town developed a landfill closure/reuse plan that provided for a 9-hole expansion of the adjacent townowned Bayberry Hills Golf Course with 7 of the 9 holes located over the capped landfill. However, since the town already needed additional drinking water supplies to handle peak summer demands in this tourist community, in the spring of 1996, the town began discussions with the Department of Environmental Protection (DEP) about utilizing the effluent from the adjacent YarmouthDennis Septage Treatment Plant (STP) as the source of irrigation water. The Yarmouth-Dennis STP had an existing biological treatment process followed by sand filtration and ultraviolet (UV) light disinfection. The original facility was not designed to meet stringent reclaimed water standards. After evaluating several options it was determined that the installation of an ozone treatment system prior to


filtration was the most efficient option to meet the proposed standards. A reclaimed water sampling plan was developed in discussions with the DEP. A two-phase sampling program was required. The phase 1 preliminary sampling program was performed in conjunction with the start-up of the new ozone treatment system and consisted of daily fecal coliform testing and continuous turbidity monitoring of the final effluent form the UV channel. Results of the sampling indicated that the proposed fecal coliform and turbidity standards could be attained. The phase 2 program consisted of comparing the results of influent septage samples from the equalization tanks and final effluent samples from the UV channel for the following parameters: Enteric Viruses, Giardia and Cryptosporidium, Heterotrophic Plate Counts (HPC), Coliphage (Male-specific and Somatic), and Clostridium perfingens. Results for these parameters indicated similar log removals with and without the ozone treatment. Development of Groundwater Discharge Permit to Use Reclaimed Water The sampling programs were developed to convince DEP that utilizing reclaimed water in Yarmouth was viable and that the interim guidelines could be attained. However, there were several steps necessary to acquire the revised groundwater discharge permit for the project. In total, it took 4 years to acquire the permit that finally allowed the reclaimed water to be utilized. The first step, which began in 1996, involved working closely with the DEP to develop a means for permitting this type of facility; Massachusetts was one of the remaining states that did not have guidelines or regulations for permitting reclaimed water facilities. Ultimately, DEP issued a set of “Interim Guidelines on Reclaimed Water” in May 1999 (Revised January 2000). These guidelines provided a mechanism for permitting reclaimed water projects under the DEP’s groundwater discharge permit regulations. A site hearing process allowed for a public comment period regarding modifications to the existing YarmouthDennis STP groundwater discharge permit so that it would include the reclaimed water and new application site. Based on all the work that had been done leading up to these events, there were very few comments received and the new groundwater discharge permit was issued on June 28, 2000. DEP added some additional monitoring parameters to the reclaimed water portion of the permit to help develop a historical database of viral and pathogenic values. The MS2 Coliphage, a viral indicator, will be sampled twice per month for the March through Novem-

ber use period, and can be tested using a fairly inexpensive means. Giardia, Cryptosporidium, and Clostridium perfringens will be sampled 4 times during the use period, which involves expensive testing procedures that take weeks to conduct. Although the reclaimed water is not to be ingested, it is believed that DEP will utilize this data in the future to develop an even greater confidence level that the current stringent reclaimed water standards are protective of public health. Groundwater Protection Management Plan Because of the unique way in which the reclaimed water portion of the groundwater discharge permit was written, the implementation of reclaimed water requires close coordination between the treatment plant staff and the golf course staff. Therefore, a Groundwater Protection Management Plan was developed to address these coordination issues. The overall purpose of the plan is to protect the area groundwater. To achieve that purpose, the plan provides an understanding of the issues involved and defines the responsibilities of the various parties. The treatment plant staff are responsible for the groundwater discharge permit compliance, which includes the reclaimed water applied as well as the water collected in the underflow from the golf course. The golf course staff are responsible for the operation and maintenance of the Links at Bayberry Hills. Thus, without close coordination between the 2 parties, permit compliance would be difficult. Based on the coordination requirements and the uniqueness of this golf course, there were 4 basic elements addressed within the Groundwater Protection Management Plan. The first element deals with the schedule for using the reclaimed water. Town water will be used during the spring months when the golf course staff will be “waking the course up” with different fertilizer applications depending on the previous winter weather conditions. This is also a period when the town can use its own potable water supply. However, in the summer months, when town water supplies are stretched, reclaimed water will be used on the golf course. It is anticipated this will occur beginning in July and will continue until November, or until the reclaimed water supplies of up to 21 million gallons by permit are depleted. The second element deals with the requirement for the use of slow release fertilizers. The third element deals with the need to reduce the quantity of commerciallyapplied fertilizer when reclaimed water is in use. The


fourth element addresses the coordination between the treatment plant staff and the golf course staff so that the above 3 elements are being done. Thus, an approval form requiring the signature of both parties has been developed for use prior to any fertilizer application on the golf course. It is believed that the Groundwater Protection Management Plan addresses the key issues between the treatment plant staff and the golf course staff so that, over time, as personnel change, the Town of Yarmouth will have an adequately maintained golf course and adequately protected groundwater supplies. It will also provide the ability to comply with the reclaimed water permit limits. Implementation of the reclaimed water project for the Town of Yarmouth has been a challenge for all parties involved due to its innovative nature for the Commonwealth of Massachusetts. However, all parties worked together to find a way to get this project implemented without compromising public health issues.

State of California. 1998. “General Plan Guidelines”, Governor’s Office of Planning and Research, (November, 1998), p.10. pub_org.html State of Florida, Florida’s Growth Management Act. 2002. Chapter 163, Part II, Florida Statutes. The Local Government Comprehensive Planning and Land Development Act. Tallahassee, Florida. State of Florida, Sunshine Law. 2002. Chapter 286, Florida Statutes. Tallahassee, Florida. Blalock Irrigation District vs. The City of Walla Walla Case 18888 Decree. March 25, 1927. Superior Court of the State of Washington. City of Walla Walla vs. Blalock Irrigation District Case 54787 Decree. September 28, 1971. Water Reclamation and Reuse, Water Quality Management Library Volume 10, edited by Takashi Asano, CRC Press 1998. Weinberg, E. and R.F. Allan. 1990. Federal Reserved Water Rights. In: Water Rights of the Fifty States and Territories, American Water Works Association, Denver, Colorado.



California Department of Water Resources Recycled Water Task Force. White Paper of the Public Information, Education and Outreach Workgroup on Better Public Involvement in the Recycled Water Decision Process (December, 2002 Draft). California State Water Resources Control Board. 1984. “In The Matter Of The Sierra Club, San Diego Chapter” Order 84-7. Cologne, Gordon and Peter MacLaggan. 1995. “Legal Aspects of Water Reclamation” in Wastewater Reclamation And Reuse (ed. Takashi Asano) American Water Works Association (Denver CO) ISBN: 1566763053 Federal Water Pollution Control Act, Public Law 92-500, 33 U.S.C. 1251-1387. Florida Department of Environmental Protection. 1999. “Water Resource Implementation Rule.” Chapter 62-40, Florida Administrative Code. Florida Department of Environmental Protection. Tallahassee, Florida. Rosenblum, Eric. “Nonpotable Recycling in San Jose, California Leads Silicon Valley Towards Sustainable Water Use”, Proceedings of the Advanced Wastewater Treatment, Recycling and Reuse Conference, Milan, Italy, September 14-16, 1998. Sheikh, Bahman., E. Rosenblum. “Accounting for the Benefits of Water Reuse,” Proceedings, AWWA/WEF 1998 Water Reuse Conference (February, 1998)


CHAPTER 6 Funding Water Reuse Systems
Like the development of other utilities, the implementation of reuse facilities generally requires a substantial capital expense. Capital improvements at the wastewater treatment facility are normally required, but transmission lines can also add significantly to capital costs. In an urban setting, reuse lines must often be added to the existing transmission infrastructure, requiring careful construction processes. And unless agricultural, industrial, and recreational reuse sites are close to reclaimed water sources, these sites will require new transmission facilities as well. In addition to the capital costs associated with reclaimed water facilities, there are also additional operation, maintenance, and replacement (OM& R) costs, including those associated with power and water quality monitoring, as well as administrative costs, such as customer billing. And, in almost all cases, implementation of a reuse system involves enhanced cross-connection programs with an associated increase in cost. These costs are typically calculated into a reclaimed water rate, expressed either as a gallonage charge or a fixed monthly fee. Even in situations where reclaimed water systems are developed in response to effluent disposal needs and customers are encouraged to make use of an “unlimited” supply at little to no charge, provisions should still be made for the day when conservation of the reclaimed water supply will be required. Another factor impacting costs is the potential drop in revenues associated with a reduction in potable water use after implementation of a reuse system. This loss of revenue can be particularly challenging if the water and wastewater systems are owned by different utilities. Consequently, multiple financial alternatives should be investigated to fund a reclaimed water system.
„ Cost-Effectiveness – the analysis of alternatives us-

ing an effectiveness scale as a measurement concept. EPA formulated “Cost-Effectiveness Analysis Guidelines” as part of its Federal Water Pollution Control Act (40 CFR Part 35, Subpart E, Appendix A). This technique requires the establishment of a single base criterion for evaluation, such as annual water production of a specific quality expressed as an increase in supply or decrease in demand. Alternatives are ranked according to their ability to produce the same result. The alternatives can include such factors as their impact on quality of life, environmental effects, etc. which are not factored into a cost/benefit analysis.

Cost/Benefit – the relationship between the cost of resources and the benefits expected to be realized using a discounted cash-flow technique. Non-monetary issues are not factored into these calculations. Financial Feasibility – the ability to finance both the capital costs and OM&R costs through locally raised funds. Examples of revenue sources include user fees, bonds, taxes, grants, and general utility operating revenues.


In the context of these definitions, the first analysis to be performed when considering a reuse system would be a cost-effectiveness analysis. This involves analyzing the relevant costs and benefits of providing additional water from fresh water sources versus reclaimed water.
Benefits that can be considered include:


Decision Making Tools

Environmental - the reduction of nutrient-rich effluent discharges to surface waters
- the conservation of fresh water supplies - reduction of saltwater intrusion

To clarify the issues to be discussed, some general terms are defined as follows:



Economic - delay in or avoidance of expanding existing water supply and treatment facilities Delay in, or elimination of, enhancements to the existing potable water treatment systems Delay in, or elimination of, enhancements to the existing wastewater treatment systems

ous externally generated capital funding source alternatives include:



Local Government Tax-Exempt Bonds – The total capital cost of construction activities for a reuse project could be financed from the sale of long-term (20-30 year) bonds. Capital needs could be funded partially through state or local grants programs or through SRF loans, particularly those programs designed specifically to support reuse.

„ Grants and State Revolving Fund (SRF) Programs –

Shared benefits should also be considered. For instance, if a benefit is received by water customers from a delay in expanding the water supply (deferred rate increase), a portion of reclaimed water costs could be shared by existing and future water customers. A similar analysis can also be made for wastewater customers who benefit from a delay in, or elimination of, increased levels of treatment associated with more stringent discharge limits. The cost/benefit analyses are conducted once feasible alternatives are selected. The emphasis of these analyses is on defining the economic impact of the project on various classes of users, (e.g., industrial, commercial, residential, agricultural). The importance of this step is that it relates the marketability of reuse relative to alternative sources, based on the end use. To elaborate, given the cost of supplying reclaimed water versus fresh water for urban use, what is the relationship of water demand to price, given both abundant and scarce resources? The present worth value of the benefits are compared to determine whether the project is economically justified and/ or feasible. As part of meeting a requirement to secure a 100-year water supply, an expansion of the reuse system was found to be more cost-effective than traditional effluent disposal coupled with increasing water supplies (Gray et al., 1996). Finally, financial feasibility determines whether sufficient financial resources can be generated to construct and operate the required reclamation facilities. Specific financial resources available will be explained in subsections 6.2, 6.3, and 6.4.

„ Capital Contribution – At times, there are special agree-

ments reached with developers or industrial users, requiring the contribution of either assets or money to offset the costs of a particular project.


Local Government Tax-Exempt Bonds

A major source of capital financing for local governments is to assume debt – that is, to borrow money by selling municipal bonds, which enables the municipality to spread the cost of the project over many years. This approach reduces the annual amount that must be raised as compared to funding the entire capital project on a “pay-as-you-go” basis from rate revenues. With many water reclamation projects, local community support will be required to finance the project. If revenue bond financing is used, this matches the revenue stream from the use of reclaimed facilities with the costs of the debt used for construction, but does not normally require voter approval. However, voter approval may be required for general obligation bonds. The types of bonds commonly used for financing public works projects are:


Externally Generated Funding Alternatives

General Obligation Bonds – Repaid through collected general property taxes or service charge revenues, and generally require a referendum vote. Underlying credit support is the full faith taxation power of the issuing entity. Special Assessment Bonds – Repaid from the receipts of special benefit assessments to properties (and in most cases, backed by property liens if not paid by property owners). Underlying credit support is the property tax liens on the specially benefited properties. Revenue Bonds – Repaid through user fees and service charges derived from operating reuse facilities (useful in regional or sub-regional projects because revenues can be collected from outside the


It is difficult to create a totally self-supporting reuse program financed solely by reclaimed water user fees. To satisfy the capital requirements for implementation of a reuse program, the majority of the construction and related capital costs are often financed through long-term water and wastewater revenue bonds, which spread the cost over multiple decades. Supplemental funds may be provided by grants, developer contributions, etc., to mitigate or offset the annual revenue requirement. The vari-



geographical limits of the borrower). Underlying credit support is the pledged revenues, such as user fees or special charges.

ating an adequate stream of revenues through local sources. State Revolving Fund

Short-Term Notes – Usually repaid through general obligation or revenue bonds. These are typically used as a method of construction or interim financing until they can be incorporated into the long-term debt.

The local government must substantiate projections of the required capital outlay, of the anticipated OM&R costs, of the revenue-generating activities (i.e., the user charge system, etc.), and of the “coverage” anticipated – that is, the extent to which anticipated revenues will more than cover the anticipated capital and OM&R costs. A local government finance director, underwriter, or financial advisor can describe the requirements to justify the technical and economic feasibility of the reuse project. Since reuse facilities are often operated as part of a water and wastewater utility fund, bonds issued will probably be issued by the combined utility and thus any financial information presented will be for a combined enterprise fund. The reuse operation will most likely not have to stand alone as a self-sufficient operation and will appear financially stronger.

The SRF is a financial assistance program established and managed by the states under general EPA guidance and regulations and funded jointly by the federal government (80 percent) and state matching money (20 percent). It is designed to provide financial assistance to local agencies to construct water pollution control facilities and to implement non-point source, groundwater, and estuary management activities, as well as potable water facilities. Under SRF, states make low-interest loans to local agencies. Interest rates are set by the states and must be below current market rates and may be as low as 0 percent. The amount of such loans may be up to 100 percent of the cost of eligible facilities. Loan repayments must begin within 1 year after completion of the facility and must be completely amortized in 20 years. Repayments are deposited back into the SRF to be loaned to other agencies. The cash balance in the SRF may be invested to earn interest, which must accrue to the SRF. States may establish eligibility criteria within the broad limits of the Clean Water State Revolving Fund (CWSRF). Basic eligible facilities include secondary and advanced treatment plants, pump stations, and force mains needed to achieve and maintain NPDES permit limits. States may also allow for eligible collection sewers, combined sewer overflow correction, stormwater facilities, and the purchase of land that is a functional part of the treatment process. Water conservation and reuse projects eligible under the Drinking Water State Revolving Fund (DWSRF) include installation of meters, installation or retrofit of water efficient devices such as plumbing fixtures and appliances, implementation of incentive programs to conserve water (e.g., rebates, tax breaks, vouchers, conservation rate structures), and installation of dual-pipe distribution systems as a means of lowering costs of treating water to potable standards. In addition to providing loans to water systems for water conservation and reuse, states can use their DWSRF set-aside funds to promote water efficiency through activities such as: development of water conservation plans, technical assistance to systems on how to conserve water (e.g., water audits, leak detection, rate structure consultation), development and implementa-


State and Federal Financial Assistance

Where available, grant programs are an attractive funding source, but require that the proposed system meets grant eligibility requirements. These programs reduce the total capital cost borne by system beneficiaries thus improving the affordability and viability of the project. Some funding agencies have an increasingly active role in facilitating water reuse projects. In addition, many funding agencies are receiving a clear legislative and executive mandate to encourage water reuse in support of water conservation. To be financially successful over time, a reuse program, however, must be able to “pay for itself.” While grant funds may underwrite portions of the capital improvements necessary in a reuse project – and in a few states, state-supported subsidies can also help a program to establish itself in early years of operation – grant funds should not be expanded for funding needs associated with annual operating costs. In fact, most federally- funded grant and loan programs explicitly prohibit the funding of OM&R costs. Once the project is underway, the program should strive to achieve self-sufficiency as quickly as possible – meeting OM&R costs and debt service requirements of the local share of capital costs by gener-


tion of ordinances or regulations to conserve water, drought monitoring, and development and implementation of incentive programs or public education programs on conservation. States select projects for funding based on a priority system, which is developed annually and must be subjected to public review. Such priority systems are typically structured to achieve the policy goals of the state and may range from “readiness to proceed” to very specific water quality or geographic area objectives. Each state was allowed to write its own program regulations for SRF funding, driven by its own objectives. Some states, such as Virginia, provide assistance based on assessing the community’s economic health, with poorer areas being more heavily subsidized with lower interest loans. Further information on the SRF program is available from each state’s water pollution control agency. Federal Policy

a rural area varies depending upon the statutory language authorizing the program. Most of these programs are administered through the USDA Rural Development Office in each state. Rural Utilities Service (RUS) offers funds through the Water and Waste Program, in the form of loans, grants, and loan guarantees. The largest is the Water and Waste Loan and Grant Program, with approximately $1.5 billion available nationwide per year. This program offers financial assistance to public bodies, eligible not-for-profits and recognized tribal entities for development (including construction and non-construction costs) of water and wastewater infrastructure. Unincorporated areas are typically eligible, as are communities with less than 10,000 people. Grants may be available to communities meeting income limits to bring user rates down to a level that is reasonable for the serviced population. Interest rates for loan assistance depend on income levels in the served areas as well. The Rural Development offices act to oversee the RUS-funded projects from initial application until the operational stage. Other Rural Development programs are offered by the Rural Housing Service and the Rural Business-Cooperative Service. Rural Housing Service offers the Community Facilities Program that may fund a variety of projects for public bodies, eligible not-for-profits, and recognized tribal entities where the project serves the community. This includes utility projects and may potentially include a water reuse project, if proper justification is provided. The Rural Business-Cooperative Service offers the Rural Business Enterprise Grant program to assist grantees in designing and constructing public works projects. A water reuse system serving a business or industrial park could potentially receive grant assistance through this program. An individual eligible business could apply for loan guarantees through the Rural Business-Cooperative Service to help finance a water reuse system that would support the creation of jobs in a rural area. Other agencies that have funded projects in cooperation with USDA may provide assistance for water reuse projects if eligibility requirements are met include the Economic Development Administration, Housing and Urban Development (Community Development Block Grant), Appalachian Regional Commission, and the Delta Regional Commission. Finally, the Bureau of Reclamation, authorized under Title XVI, the Reclamation Wastewater and Groundwater Study and Facilities Act; PL 102-575, as amended, Reclamation Recycling and Water Conservation Act of 1996; PL 104-266, Oregon Public Lands Transfer and Protection Act of 1998; PL 105-321, and the Hawaii

The Clean Water Act of 1977, as amended, supports water reuse projects through the following provisions:

Section 201 of PL 92-500 was amended to ensure that municipalities are eligible for “201” funding only if they have “fully studied and evaluated” techniques for “reclaiming and reuse of water.” A 201 facility plan study must be completed to qualify for state revolving loan funds. Section 214 stipulates that the EPA administrator “shall develop and operate a continuing program of public information and education on water reclamation and reuse of wastewater. . .” Section 313, which describes pollution control activities at federal facilities, was amended to ensure that wastewater treatment facilities will utilize “recycle and reuse techniques: if estimated life-cycle costs for such techniques are within 15 percent of the most cost-effective alternative.” Other Federal Sources



There are a number of federal sources that might be used to generate funds for a water reuse project. While there are many funding sources, only certain types of applicants or projects are eligible for assistance under each program. The U.S. Department of Agriculture (USDA) has several programs that may provide financial assistance for water reuse projects in rural areas, but the definition of


Water Resources Act of 2000; PL 106-566, provides for the Bureau to conduct appraisal and feasibility studies on water reclamation and reuse projects. The Bureau can then fund construction of reuse projects after Congressional approval of the appropriation. This funding source is restricted to activities in the 17 western states unless otherwise authorized by Congress. Federal participation is generally up to 25 percent of the capital cost. Information about specific funding sources can be found in the Catalog of Federal and Domestic Assistance, prepared by the Federal Office of Management and Budget and available in federal depository libraries. It is the most comprehensive compilation of the types and sources of funding available. State, Regional, and Local Grant and Loan Support

projects have been completed and are currently providing reclaimed water for a variety of non-potable uses. A comprehensive water reuse study in California concluded that funding was the primary constraint in implementing new water reuse projects (California State Water Resources Control Board, 1991). To assist with the financial burden, grant funds are now available from the California Department of Water Resources for water conservation and groundwater management. Proposition 13 Safe Drinking Water, Clean Water, Watershed Protection and Flood Protection Bond Act provides funds for:
„ „ „ „ „ „ „

Agriculture water conservation capital outlay Groundwater recharge construction loans Groundwater storage construction grants Infrastructure rehabilitation feasibility study grants Infrastructure rehabilitation construction grants Urban streams restoration program grants Urban water conservation capital outlay grants

State support is generally available for wastewater treatment facilities, water reclamation facilities, conveyance facilities, and, under certain conditions, for on-site distribution systems. A prime source of state-supported funding is provided through SRF loans. Although the number of states that have developed other financial assistance programs that could be used for reuse projects is still limited, there are a few examples. Texas has developed a financial assistance program that includes the Agriculture Water Conservation Grants and Loans Program, the Water Research Grant Program, and the Rural Water Assistance Fund Program. There is also a planning grant program – Regional Facility Planning Grant Program and Regional Water Planning Group Grants – that funds studies and planning activities to evaluate and determine the most feasible alternatives to meet regional water supply and wastewater facility needs. Local or regional agencies, such as the regional water management districts in Florida, have taxing authority. In Florida, a portion of the taxes collected has been allocated to the funding of alternative water sources including reuse projects, which have been given a high priority, with as much as 50 percent of a project’s transmission system eligible for grant funding. Various methods of prioritization exist, with emphasis on those projects that are of benefit to multi-jurisdictional users. The State of Washington began its process of addressing water reclamation and reuse issues by passing the Reclaimed Water Act of 1992. In 1997, the State Legislature provided $10 million from the Centennial Clean Water Fund to help fund 5 demonstration projects. These

AB303, the Local Groundwater Management Assistance Act of 2000, also provides grants. Funds have been used by Daly City, California to develop a groundwater-monitoring program and to refine models of the Westside Basin aquifer. The passage of California’s Proposition 50 in November 2002 makes funds available for projects to “protect urban communities from drought, increase supplies of clean drinking water, reduce dependence on imported water, reduce pollution of rivers, lakes, streams, and coastal waters, and provide habitat for fish and wildlife.” This includes financing for “groundwater recharge and management projects.” The State Water Resources Control Board (SWRCB) and the U.S. Bureau of Reclamation have played major roles in providing capital funding for local projects.


Capital Contributions

In certain circumstances, where reclaimed water is to be used for a specific purpose, such as cooling water, it may be possible to obtain the capital financing for new transmission facilities directly from one or more major users that benefit from the available reclaimed water supply.


One example of such a capital contribution would be construction of a major reuse transmission line by a developer who then transfers ownership to the utility for operation and maintenance. Another example is a residential housing developer, golf course, or industrial user who may provide the pipeline, financing for the pipeline, or provide for a pro-rata share of construction costs for a specific pipeline. In the event the private entity initially bears the entire capital cost of the improvement, such an approach may include provisions for reimbursement to the entity from future connections to the contributed facility for a specified period of time.

negligible fee may have been adopted to support the “all you can use” mentality. Very often a fixed rate will be used to simplify billing and eliminate penalties for overuse in the form of increased costs. While such an approach may seem to be justified when a project begins, this rationale for basing user fees falls by the wayside as water resources become stressed and reclaimed water supplies become a valuable resource. User charges would be utilized to generate a stream of revenues with which to defray the OM&R costs of the reuse facility and the debt service of any bonds or loans issued. In a reclaimed water user charge system, the intent of an equitable rate policy is to allocate the cost of providing reuse services to the recipient. With a user charge system, it is implicit that there be select and identifiable user categories to which the costs of treatment and distribution can be allocated. There are 2 prime means of allocating costs that are to be incorporated into a user charge: the proportionate share cost basis and the incremental cost basis. These 2 methods are discussed in more detail in Section 6.4. Determining an equitable rate policy requires consideration of the different service needs of individual residential users (single-family and multi-family) as compared to other “larger” users with bigger irrigable areas, such as golf courses and green spaces. In many cases, a lower user rate can be justified for such large users than for residential customers. As an example, large users may receive reclaimed water into on-site storage facilities and then subsequently repump the water into the irrigation system, enabling the supplier to deliver the reclaimed water, independent of daily peak demands, using lowpressure pumps rather than providing high-pressure delivery on demand as required by residential users. Some multi-family customers may be treated as “large” users under this example, unless the reclaimed water is delivered at high pressure directly into the irrigation system. This flexibility in delivery and the low-pressure requirements can often justify the lower rate. At the same time, keeping reclaimed water rates competitive for large users when considering alternative sources of water, such as groundwater, is another consideration. The degree of income from other sources, such as the general fund and other utility funds, must be considered in determining the balance of funding that must come from reuse rates. Residential user fees must be set to make water reuse an attractive option to potable water or groundwater. Alternatively, local regulations can prescribe that reclaimed water must be used for irrigation and other outdoor nonpotable uses in areas where it is available so usage becomes less sensitive to pricing. Although re-


Internally Generated Funding Alternatives

While the preceding financing alternatives describe the means of generating construction capital, there is also a need to provide funding for OM&R costs, as well as debt service on borrowed funds. Examples of various internally-generated funding sources are highlighted, with details, in the following subsections. In most cases, a combination of several funding sources will be used to recover capital and OM&R costs. The following alternatives may exist for funding water reuse programs.
„ „ „

Reclaimed water user charges Operating budget and cash reserves of the utility Local property taxes and existing water and wastewater user charges Public utility tax Special assessments or special tax districts Connection fees

„ „ „

The City of Reno, Nevada, used a combination of special assessment districts bonds, revenue bonds, developer agreements, connection fee charges, user fees, and general fund advances as part of the creation of its reclaimed water system (Collins, 2000).


Reclaimed Water User Charges

The first source of funding considered should be a charge to those receiving reclaimed water services. As noted in the introduction, reclaimed water systems may well begin life as effluent disposal programs. Under such circumstances, reclaimed water “customers” are likely to be encouraged to use as much water as they want. A


claimed water may have to be priced below potable water to encourage its use, reuse rates may also be set to discourage indiscriminate use by instituting volume (per gallon) charges rather than a flat fee; however, as reclaimed water has become recognized as an increasingly valuable element of an overall water resources plan, the trend is to meter reuse consumption to better monitor and control its use.

revenues designated for expenses associated with the reuse project. Similarly, the user charge currently paid for water and wastewater services could be increased. Like using the operating budget or cash reserves, the use of property taxes or user charges may be desirable if the expenditures for the project are not anticipated to be sizable or if a general benefit accrues to the entire community. Ad valorem property taxes, unlike user charges, raise funds on the basis of assessed value of all taxable property, including residential, commercial, and industrial. Property value can be an appropriate means of allocating the costs of the service improvements if there is a “general good” to the community. It is also a useful means of allocating the cost of debt service for a project in which there is general good to the community and in which the specific OM&R costs are allocated to the direct beneficiaries. A contribution of ad valorem property tax revenues might be appropriate for such reuse applications as:
„ „ „


Operating Budget and Cash Reserves

Activities associated with the planning and possible preliminary design of reuse facilities could be funded out of an existing wastewater utility/department operating budget. A water supply agency seeking to expand its water resources would find it appropriate to apply a portion of its operating funds in a similar way. It could be appropriate, for example, to utilize funds from the operating budget for planning activities or business costs associated with assessing the reuse opportunity. Furthermore, if cash reserves are accruing for unspecified future capital projects, those funds could be used for design and construction costs, or a portion of the operating revenues from utility revenues can be set aside in a cash reserve for future needs. The obvious advantage of using this alternative source of funding is that the utility board or governing body of the water and/or wastewater department or utility can act on its own initiative to allocate the necessary resources. These sources are especially practical when relatively limited expenditures are anticipated to implement or initiate the reuse program, or when the reuse project will provide a general benefit to the entire community (as represented by the present customers of the utility). In addition, utilizing such resources is practical when the reclaimed water will be distributed at little or no cost to the users, and therefore, will generate no future stream of revenues to repay the cost of the project. While it is ideal to fully recover all direct costs of each utility service from customers, it may not be practical during the early phases of a reuse system implementation.

Irrigation of municipal landscaping Fire protection Water for flushing sewers Groundwater recharge for saltwater intrusion barriers Parks and recreational facility irrigation



All such projects have benefits, either to the residents of the municipality in general, or to those who can be isolated in an identifiable special district. Resources generated by increasing any existing user charges can be used in a similar manner. However, to do so equitably, benefits of the proposed project should primarily accrue to those presently utilizing the services of the water or wastewater utility. This would be the case, for example, when water reuse precludes the need to develop costly advanced treatment facilities or a new water supply source. Contributions from the water and wastewater systems may be warranted whenever there is a reduction in the average day or peak day water demand or when the reuse system serves as a means of effluent disposal for the wastewater system. The City of St. Petersburg, Florida, for example, provides as much as 50 percent of the urban reuse system operations costs from water and wastewater system funds. The significant reduction in potable water demand achieved through water reuse has


Property Taxes and Existing User Charges

If the resources available in the operating budget or the cash reserves of the utility are not sufficient to cover the necessary system, OM&R activities, and capital financing debt, then another funding source to consider is revenues generated by increasing existing levies or charges. If some utility costs are currently funded with property taxes, levies could be increased and the new


allowed the City to postpone expansion of its water treatment plant.


Public Utility Tax

The State of Washington took a rather innovative approach to funding when it passed a major water bill in 2001. The new law addresses several key areas in water resource management, including an incentive program to promote conservation and distribution of reclaimed water. The Public Utility Tax (Chapter 82.16 Revised Code of Washington) is levied on gross income of publicly and privately-owned utilities. The incentive program (Chapter 237), which exempts 75 percent of the amounts received for reclaimed water services for commercial and industrial uses, also allows reclaimed water utilities to deduct from gross income 75 percent of amounts expended to improve consumer water use efficiency or to otherwise reduce the use of water by the consumer. (Focus, Washington State Department of Ecology, August 2001) Examples of eligible measures are:
„ Measures that encourage the use of reclaimed water

Special assessments may be based on lot front footage, lot square footage, or estimated gallon use relative to specific customer types. This revenue alternative is especially relevant if the existing debt for water and wastewater precludes the ability to support a reuse program, or if the area to be served is an independent service area with no jurisdictional control over the water or wastewater systems. The implementation of reclaimed water systems will reduce potable water consumption, corresponding to a reduction of revenues. This must be factored into the funding analysis.


Impact Fees

in lieu of drinking water for landscape or crop irrigation

Measures that encourage the use of moisture sensors, flow timers, low-volume sprinklers, or drip irrigation for efficiencies in reclaimed water use

Impact fees, or capacity fees, are a means of collecting the costs of constructing an infrastructure element, such as water, wastewater, or reuse facilities, from those new customers benefiting from the service. Impact fees collected may be used to generate construction capital or to repay borrowed funds. Frequently, these fees are used to generate an equitable basis for cost recovery between customers connecting to the system in the early years of a program and those connecting in the later years. The carrying costs (interest expenses) are generally not fully recovered through the impact fee, although annual increases above a base cost do provide equity between groups connecting in the early years and those in later years. Impact fees for water reuse systems are implemented at the discretion of the governing body. However, requiring a fee to be paid upon applying for service prior to construction can provide a strong indication of public willingness to participate in the reuse program. Incentive programs can be implemented in conjunction with impact fees by waiving the fee for those users who make an early commitment to connect to the reclaimed water system (e.g., for the first 90 days after construction completion) and collecting the fee from later connections.

Many variations on this incentive theme could be adopted by states, such as imposing a utility tax directly on large water users and granting exemptions for reclaimed water use.


Special Assessments or Special Tax Districts

When a reuse program is designed to be a self-supporting enterprise system, independent of both the existing water and wastewater utility systems, it may be appropriate to develop a special tax or assessment district to recover capital costs directly from the benefited properties. The advantage of this cost recovery mechanism is that it can be tailored to collect the costs appropriate to the benefits received. The City of Cape Coral, Florida, is one example of an area using special assessments to fund dual-water piping capital costs for fire protection and irrigation water. This special assessment was levied at an approximate cost of $1,600 per singlefamily residence with financing over 8 years at 8 percent annual interest. In addition, a monthly user charge is also applied to the water and wastewater billing to assist in defraying operating costs.


Incremental Versus Proportionate Share Costs
Incremental Cost Basis

The incremental cost basis allocates only the marginal costs of providing service to the customer. This system can be used if the community feels that the marginal reclaimed water user is performing a social good by conserving potable water, and should be allocated only the additional increment of cost of the service. However, if the total cost savings realized by reuse are being enjoyed only by the marginal user, then in effect, the rest of the community is subsidizing the service. For example,


an ocean outfall used as the primary means of effluent disposal could be tapped and reclaimed water mains extended to provide irrigation to one or more developments in an area that formerly used potable water. In this example, it may be appropriate to charge the developments only for the cost of installing the additional mains plus any additional treatment that might be required.

claimed water service. This could occur, for example, if treatment for nutrient removal had been required for a surface water discharge but would not be necessary for agricultural reuse. As previously noted, because reclaimed water is a different product from potable water and has restrictions on its use, it may be considered a separate, lower valued class of water and priced below potable water. Thus, it may be important that the user charges for reuse be below, or at least competitive with, those for potable water service. However, often the current costs of constructing reuse facilities cannot compete with the historical costs of an existing potable water system. One means of creating a more equitable basis for comparison is to associate new costs of potable water supplies to the current costs of potable water, as well as any more costly treatment methods or changes in water treatment requirements that may be required to meet current regulations. When creating reuse user fees, it may be desirable to deduct incremental potable water costs from those charged for reuse because reuse is allowing the deferral or elimination of developing new potable water supplies or treatment facilities. The perceived inequalities between reclaimed water and potable water may be eliminated where potable water is in short supply and subject to seasonal (or permanent) restrictions. For customers that cannot tolerate uncertainty in deliveries, a source of reclaimed water free from restrictions might be worth more than traditional supplies. To promote certain objectives, local communities may want to alter the manner of cost distribution. For example, to encourage reuse for pollution abatement purposes by eliminating a surface water discharge, the capital costs of all wastewater treatment, reclaimed water transmission, and reclaimed water distribution can be allocated to the wastewater service costs. To promote water conservation, elements of the incremental costs of potable water may be subtracted from the reuse costs to encourage use of reclaimed water. For water reuse systems, the proportionate share basis of allocation may be most appropriate. The allocation should not be especially difficult, because the facilities required to support the reuse system should be readily identifiable. As shown in the previous equations, it is appropriate to allocate to wastewater charges the costs of all treatment required for compliance with NPDES permits. All additional costs, including the costs of reclamation and conveyance of reclaimed water, would be allocated to the water reuse user charge.


Proportionate Share Cost Basis

Under the commonly used proportionate share basis, the total costs of the facilities are shared by the parties in proportion to their usage. In apportioning the costs, consideration must be given to the quantity and quality of the water, the reserve capacity that must be maintained, and the use of any joint facilities, particularly means of conveyance. In determining the eventual cost of reuse to the customer base, the apportionment of costs among wastewater users, potable water users, and reclaimed water users must be examined. The allocation of costs among users also must consider the willingness of the local community to subsidize a reuse program. A proportional allocation of costs can be reflected in the following equations: Total wastewater service = wastewater treatment to permitted disposal standards + effluent disposal + transmission + collection water treatment + water supply + transmission + distribution

Total potable water service =

Total reclaimed water service = [reclaimed water treatment – treatment to permitted disposal standards] + additional transmission + additional distribution + additional storage These equations illustrate an example of distributing the full costs of each service to the appropriate system and users. The first equation distributes only the cost of treating wastewater to currently required disposal standards, with any additional costs for higher levels of treatment, such as filtration, coagulation, or disinfection, assigned to the cost of reclaimed water service. In the event that the cost of wastewater treatment is lowered by the reuse alternative because current effluent disposal standards are more stringent than those required for the reuse system, the credit accrues to the total cost of re-


General and administrative costs should also be allocated proportionately to all services just as they would be in a cost-of-service allocation plan for water and wastewater service. In some cases, lower wastewater treatment costs may result from initiating reclaimed water usage. Therefore, the result may be a reduction in the wastewater user charge. In this case, depending on local circumstances, the savings could be allocated to either the wastewater customer or the reclaimed water customer, or both. Table 6-1 provides a range of credits that can be applied to the financial analysis of water reclamation projects based on experience in California (Sheikh et al., 1998). With more than one category or type of reclaimed water user, different qualities of reclaimed water may be needed. If so, the user charge becomes somewhat more complicated to calculate, but it is really no different than calculating the charges for treating different qualities of wastewater for discharge. If, for example, reclaimed water is distributed for 2 different irrigation needs with one requiring higher quality water than the other, then the user fee calculation can be based on the cost of treatment to reach the quality required. This assumes that it is cost-effective to provide separate delivery systems to customers requiring different water quality. Clearly this will not always be the case, and a cost/benefit analysis of treating the entire reclaimed water stream to the highest level required must be compared to the cost of separate transmission systems. Consideration should also be given to providing a lower level of treatment to a single reclaimed water transmission system with additional treatment provided at the point of use as required by the customer. Estimating the operating cost of a reclaimed water system involves determining those treatment and distribution components that are directly attributable to the reclaimed water system. Direct operating costs involve additional treatment facilities, distribution, additional water quality monitoring, and inspection and monitoring staff. Table 6-1. Credits to Reclaimed Water Costs
Benefit Water supply Water supply reliability Effluent disposal Downstream watershed Energy conservation

Any costs saved from effluent disposal may be considered a credit. Indirect costs include a percentage of administration, management, and overhead. Another cost is replacement reserve, i.e., the reserve fund to pay for system replacement in the future. In many instances, monies generated to meet debt service coverage requirements are deposited into replacement reserves.


Phasing and Participation Incentives

The financing program can be structured to construct the water reuse facilities in phases, with a target percentage of the potential customers committed to using reclaimed water prior to implementation of each phase. This commitment assures the municipal utility decision makers that the project is indeed desired and ensures the financial stability to begin implementation. Incentives, such as a reduction or waiver of the assessment or connection fee for those connections to the system within a set time frame, can be used to promote early connections or participation. The San Antonio, Texas, reclaimed water system charges for reclaimed water will be $280/ acre-foot ($0.86/1,000 gallons), the same as the cost of potable water. As an incentive for users to sign up for this service, the city offered a one-time $900/acre-foot ($2.76/1,000 gallons) credit to cover the user’s costs of converting to reclaimed water (Martinez, 2000). Adequate participation to support implementation can be determined by conducting an initial survey in a service area, followed by a formal voted service agreement for each neighborhood. If the required percentage of residents in a given neighborhood agree to participate, facilities will be constructed in that area. Once this type of measure is taken, there is an underlying basis for either assessing pipeline costs, or charging using a monthly fixed fee, because the ability to serve exists. The rate policy may also include a provision for assessments or charges for undeveloped properties within a neighborhood served by a reclaimed water system.

Applicability Very common Very common Very common Common Situational

Value ($/acre-feet) $300 - $1,100 $100 - $140 $200 - $2,000 $400 - $800 0 to $240



Sample Rates and Fees
Connection Fees

Connection charges to a dual distribution system are often based on the size of the reclaimed water system being served. For example, in Cocoa Beach, Florida, customers are charged a connection fee based on the size of the reclaimed water service line. The connection fees are $100, $180, and $360 for a 3/4-inch, 1-inch, and 1-1/2-inch service line, respectively. As an alternative to connection fees, a flat monthly rate can be charged to each user for a specified length of time until the capital costs associated with the system are paid off. This alternative is often preferred to spread out the costs associated with connection fees.

Figure 6-1 provides the results of a similar survey of potable and reclaimed water rates for utilities in southwest Florida (Personal Communication with Dennis Cafaro, 2003). With the exception of Barron Collier utilities, reclaimed water rates tend to be less than 50 percent of the potable water rates, with some rates for reuse less than 20 percent that of potable water. These results provide additional evidence that reclaimed water rates are highly dependent on local conditions.


User Fees

The procedure for establishing rates for reclaimed water can be similar to the procedure for establishing potable water and wastewater rates. If reclaimed water is metered, then user rates can be based upon the amount of reclaimed water used. This will tend to temper excessive use. If meters are not used, then a flat rate can be charged. Table 6-2 presents user fees for a number of existing urban reuse systems. It is common for the cost of reclaimed water service to be based on a percentage of the cost of potable water service. One might assume that reclaimed water rates would always be less than that of potable water but this may not be the case. A recent survey of reclaimed water utilities in California (Table 6-3) shows the range of discounts for reclaimed water (Lindow and Newby, 1998). This survey clearly shows that reclaimed water can command rates equal to that of potable water depending on the specific nature of local water resources.

To further reinforce the concept that reclaimed water is a valuable resource, utilities may consider not only charging for reclaimed water by the gallon, but also implementing a conservation rate structure to encourage efficient use. Conservation rate structures provide economic incentives for consumers to limit water use. To the extent possible, they should achieve similar results in all customer classes, be equitable within and among customer classes, support the utility’s financial requirements, and can be revenue neutral. Structures can significantly reduce water use without government expenditure or new regulation, while helping to protect both the quantity and quality of water resources. For example, at system startup some residential customers in the City of Venice, Florida were charged a flat rate for reclaimed water service. When the rate structure was changed to charge customers for the actual volume of water used, including an inclining conservation rate, demand was reduced by 10 to 15 percent. However, no change in the peak demand water use was observed – suggesting peak use was driven by actual need and reductions were the result of more efficient water use in low demand periods (Farabee et al., 2002).


Case Studies
Unique Funding Aspects of the Town of Longboat Key, Florida Reclaimed Water System

Table 6-3.

Discounts for Reclaimed Water Use in California
Jurisdiction Cost Percentage of Potable W ater (%) 53 56 80 80 85 90 100 100 100

City of Long Beach Marin Municipal Water District City of Milpitas Orange County Water District San Jose Water Company Irvine Ranch Water District Carlsbad Municipal Water District East Bay Municipal Utility District Otay Water District

Longboat Key is a barrier island community located on Florida’s Gulf coast. The town lies within 2 counties—the northern portion of Longboat Key is in Manatee County and the southern portion is in Sarasota County. The island is surrounded by the Gulf of Mexico on the west and Sarasota Bay on the east. The town’s geographical location severely limits local water resources. Since its inception in 1972, the Town of Longboat Key has received potable water and wastewater services from Manatee County.

Landscape irrigation accounts for approximately a quarter of the town’s potable water use. In 2002, it was necessary for the town to seek an alternative water source for irrigation since its current potable water use exceeded what is available through Manatee County agreement al-


Table 6-2.

User Fees for Existing Urban Reuse Systems

Location Amarillo, Texas

User Fee $0.15/1,000 gallons Residential (not metered): ▪ $8/month/acre Commercial (metered): ▪ $0.26/1,000 gallons

Cocoa Beach, Florida


Colorado Springs, Colorado

$0.00685/cubic foot ($0.91/1,000 gallons) Major agriculture: ▪ $0.10/1,000 gallons Agriculture, golf course: ▪ $0.20/1,00 gallons Other: ▪ $0.55/1,000 gallons $0.71/1,000 gallons

County of Maui, Hawaii


Henderson, Nevada


San Rafael, California


Tier 1: $2.02/CCF for 0-100% of water budget Tier 2: $3.89/CCF for 100-150% of water budget Tier 3: $7.64/CCF for over 150% of water budget Inside service area: ▪ $280/AF ($0.86/1,000 gallons) for 0-25 AF/month ▪ $260/AF ($0.80/1,000 gallons) for 25-50 AF/month ▪ $240/AF ($0.74/1,000 gallons) for 50-100 AF/month ▪ $220/AF ($0.68/1,000 gallons) for 100-200 AF/month ▪ $200/AF ($0.61/1,000 gallons) for 200+ AF/month Residential (not metered): ▪ $10.36/month for first acre + $5.92/month for each additional acre $0.18/1,000 gallons Residential - Flat Rate ($/month) ▪ Average = $13.81 ▪ Range = $0.00 - $350.003 Residential - Gallonage Charge ($/1,000 gallons) ▪ Average = $0.32 ▪ Range = $0.00 - $1.25 Non-Residential - Flat Rate ($/month) ▪ Average = $445.35 ▪ Range = $0.00 - $12,595.00 Non-Residential Gallonage Charge ($/1,000 gallons) ▪ Average = $0.26 ▪ Range = $0.00 - $2.50

South Bay, California


St. Petersburg, Florida Wheaton, Illinois1


Summary of Florida Reuse Systems



User fees as reported in management practices for nonpotable water reuse, Project 97IRM-6, Water Environment Research Foundation, 2001.
Reuse Rates as reported in the Florida Department of Environmental Protection, Reuse Inventory Report, June 2002.



Includes lump sum rates charged to residential developments as well as individual residential customers.


Figure 6-1.

Comparison of Reclaimed Water and Potable Water Rates in Southwest Florida

locations. Historically, the town has also used groundwater to meet approximately 80 percent of its irrigation demands. However, a decline in groundwater quality attributed to saltwater intrusion caused by long-term withdrawals and probable overpumping has been observed. After the review and evaluation of many alternatives, the Town of Longboat Key opted for a reclaimed water system with supply provided by an adjoining jurisdiction, the City of Sarasota, Florida. The project will require:

The Longboat Key reclaimed water transmission system will connect to the City of Sarasota’s existing reclaimed water system. Two and a half million gallons per day of reclaimed water will be available from the City of Sarasota. The conceptual planning cost for the project is estimated to be $28,166,000. The reclaimed water rate structure has been designed so the system can be financially self-sufficient. The end user costs are the true cost of providing the service. The estimated cost per 1,000 gallons will be approximately $2.67. By obtaining funding through the SRF loan program, the town will be able to satisfy the capital requirements for system implementation. Since loan repayments are not required to begin until 1 year after completion of the facility, semi-annual debt service payments and OM&R costs will be satisfied from the operating revenues of the reclaimed water system. Water and wastewater revenues are not intended to be used to pay for the reclaimed water system, but instead will serve as a backup pledge to the pledge of reclaimed water revenues for the SRF loan. To the extent that water and wastewater revenues are used to make any semi-annual loan payments, the town intends to reim-

Installation of a subaqueous reclaimed water transmission main across Sarasota Bay Construction of aquifer storage and recovery facilities


„ Construction of delivery pumping stations „

Construction of a 2.5-million-gallon (9,460-m3) storage tank Construction of associated distribution mains



burse its water and wastewater revenues fund with reclaimed water revenues. The reclaimed water revenue source is contingent on commitments in the form of user agreements from condominium and homeowner’s associations. The public has voted for a town-required referendum authorizing the financing of a reclaimed water system.

salination Research and Innovation Partnership (DRIP), Water Environmental Research Foundation (WERF), Proposition 13, etc.


Financial Assistance in San Diego County, California

RWDF provides Authority member agencies financial assistance up to $100 per acre-foot ($0.31 per 1,000 gallons) for the development of reclaimed water projects capable of relieving a demand on the Authority. Project expenses must exceed project revenues. Funding is available for up to 25 years based on financial need. local projects during the initial years of operation. The Metropolitan Water District of Southern California offers an incentive of up to $250 per acre-foot ($0.77 per 1,000 gallons) for up to 25 years for reclaimed water and groundwater development projects that offset demands for imported water.

Water reclamation is an important component of the San Diego region’s local water resources. A number of agencies in San Diego continue to implement and expand their water reuse projects. Currently, about 12,000 acrefeet (3.9 billion gallons) per year of reclaimed water is beneficially reused within the service area of Water Authoriy Board of the County of San Diego (Authority). Approximately 64 percent of the water is used for agriculture, landscape irrigation, and other municipal and industrial uses; the remaining 36 percent is recharged into groundwater basins. This number is projected to increase to over 53,000 acre-feet per year (17.3 billion gallons per year) by 2020. Financial assistance programs play a critical role in the development of reclaimed water supplies. There are a number of financial assistance programs available to San Diego County agencies: the Authority’s Financial Assistance Program (FAP) and Reclaimed Water Development Fund (RWDF); the Metropolitan Water District of Southern California’s Local Resources Program (LRP); the U.S. Bureau of Reclamation’s Title XVI Grant Program; and the State Water Resources Control Board’s low-interest loan programs. Together, these programs offer funding assistance for all project phases, from initial planning and design to construction and operation. Examples of how these funds facilitate water reuse projects in San Diego are described below:

„ LRP is designed to ensure the financial feasibility of


Grant Funding Through the Southwest Florida Water Management District

FAP provides loans to Authority member agencies for water reuse facilities planning, feasibility investigations, preliminary engineering studies, and research projects related to water reuse and/or groundwater development. The Authority provides funding on a 50:50 cost sharing basis up to $50,000 for any given project activity. opment in the form of grants. In order to receive FAP funding for these types of studies, a local agency must have secured partial funding from at least one other source such as the American Water Works Association Research Foundation (AWWARF), De-

The Southwest Florida Water Management District (SWFWMD) is 1 of 5 water management districts in Florida with responsibilities for: water quality, natural systems improvement, flood protection, and water supply in a 10,000-square-mile (25,900-km2) area. The SWFWMD is unique among the water management districts in Florida in that, beyond the similar structure of the governing boards, it has 9 basins with jurisdictional boundaries encompassing the major watersheds making up the District. In 8 of the 9 basins, populations have increased such that boards have been appointed to react to local, sub-regional water resource issues. These boards sponsor projects in coordination with local governments, private citizens, and private businesses, to improve, protect, and restore the water resources of their respective areas. These basin boards, like the Governing Board, have the authority to levy ad valorem taxes up to 0.5 of a mil within their boundaries. The SWFWMD basin boards have provided local funds for local water resource-related projects since the District’s creation in 1961. Originally, the focus of the basin boards and the Governing Board was on funding flood control projects. In the late 1980s, the basin priorities began to shift to the identification and funding of projects that focus on water conservation and the development of alternative water sources. Recognizing the importance of their ability to support local governments by providing solutions to the growing issues surrounding water supply, the basins adopted a

„ FAP funds are also available for research and devel-


more proactive role in addressing local non-regulatory water issues. The Cooperative Funding Initiative, New Water Sources Initiative, and Water Supply and Resource Development funding was established in recognition of the growing need for a structured approach to projects in order to maximize the SWFWMD’s effectiveness in choosing and funding water resource projects and budgeting for their completion. The SWFWMD funds up to 50 percent of a project’s capital cost and over the past 15 years has budgeted more than $182,000,000 in financial contributions towards reclaimed water development. As a result of Governing Board and basin board participation, more than 214 reuse projects totaling $494,000,000 in capital costs have been funded since Fiscal Year 1987. Source: SWFWMD, 2003.

The cost of Phase IA is estimated at approximately $52 million. Up to 25 percent of this cost is being funded by the federal government through the Federal Reclamation Projects Authorization and Adjustment Act of 1992. Up to 50 percent of the total cost is being funded by the State of California through the Environmental Water Act of 1989. The remaining 25 percent of the total cost is being funded by ratepayers through special conservation and reclamation rate adjustments. Table 6-4 provides calculations, in cost per acre-foot, for reclaimed water with and without federal and state requirements. Based on these funding reimbursement percentages, Phase IA of the EVWRP will provide water at an estimated cost of $478 per acre-foot ($1.47 per 1,000 gallons), with a net cost of approximately $194 per acrefoot ($0.60 per 1,000 gallons) when state and federal funding is considered. Even if state or federal funding had not been available, the EVWRP would still provide a new reliable source of water at a cost comparable to other water supplies, and significantly less expensive than other new supply options. (According to the City Of Los Angeles Department of Water and Power Urban Water Management Plan Fiscal Year 1997-1998 Annual Update, seawater might be desalinated using new technology, which has produced desalted ocean water at a cost of about $800 per acre-foot ($2.35 per 1,000 gallons) in pilot tests, or approximately $2,000 per acre-foot ($6.14 per 1,000 gallons) using current technology.) Furthermore, the EVWRP has other benefits, which have not been quantified, such as the reduction of water imported from the Mono Basin and improved water system reliability resulting from a new local supply of water. Orange County Groundwater Replenishment (GWR) System Under the Orange County GWR System, highly treated reclaimed water will be pumped to either existing spreading basins, where it will percolate into and replenish the groundwater supply, or to a series of injection wells that act as a seawater intrusion control barrier. The GWR System will be implemented in 3 phases, providing a peak daily production capacity of 78,400 acre-feet per year (70 mgd) by the year 2007, 112,000 acre-feet per year (100 mgd) by 2013, and 145,600 acre-feet per year (130 mgd) by 2020. Table 6-5 shows a conservative preliminary estimate of the capital and OM&R costs for Phase I of the GWR System based on December 2003 estimates. The expected project benefits and their economic values (avoided costs) include:


Use of Reclaimed Water to Augment Potable Supplies: An Economic Perspective (California)

To accurately assess the cost-effectiveness of any reuse project, including an indirect potable water reuse project, all potential benefits of the project must be considered. The beneficial effects of an indirect potable reuse project often extend beyond the sponsoring agency, providing regional benefits and, in many cases, benefits that extend statewide and beyond. In certain settings, indirect potable reuse projects may provide for large-scale beneficial use of reclaimed water with relatively modest additional infrastructure requirements. Examples of 2 such indirect potable reuse projects are underway in California: the East Valley Water Recycling Project (EVWRP), and the Orange County Groundwater Replenishment (GWR) System. East Valley Water Recycling Project Phase IA of the EVWRP includes approximately 10 miles (16 km) of 54-inch (137-cm) diameter pipeline and a pumping station to deliver tertiary treated reclaimed water from the Donald C. Tillman Water Reclamation Plant to the Hansen Spreading Grounds. Phase IA also includes an extensive monitoring well network designed to track the reclaimed water as it travels through the San Fernando Groundwater Basin from the spreading grounds to domestic production wells. This project will initially deliver up to 10,000 acre-feet per year (6,200 gpm) to the Hansen Spreading Grounds. Phase IB of the EVWRP will include construction of an additional pipeline to deliver reclaimed water to the Pacoima Spreading Grounds.


Table 6-4.

Estimated Capital and Maintenance Costs for Phase IVA With and Without Federal and State Reimbursements
Without Federal and State Reimbursement With 25% Federal and 50% State Reimbursement $52,000,000 $26,000,000 $13,000,000 $13,000,000 $944,436 $100 10,000 AF $194 per acre-foot ($0.60 per 1,000 gal)

Capital Costs State Reimbursement (50%) Federal Reimbursement (25%) Net DWP Capital Expenditure Amortized Net Capital Expenditure (6% interest for 30 years) Operation & Maintenance Cost per Acre-foot Annual Delivery Cost of Delivered Water (AF)

$52,000,000 -0-0$52,000,000 $3,777,743 $100 10,000 AF $478 per acre-foot ($1.47 per 1,000 gal)

1. Alternative Water Supply – If the GWR System is not implemented, Water Factory 21 would have to be rehabilitated at a construction cost of approximately $100 million to provide the water needed for seawater intrusion control via groundwater injection. Additional imported water at a yearly cost of approximately $4 million to $10 million would have to be purchased for use at the spreading basins as recharge water. In times of drought, there is also a penalty imposed on using imported water supplies, ranging from $175 to $250 per acre-foot, potentially adding fees up to $10.7 million a year. By implementing the GWR System, approximately $27.4 million in annual costs are avoided. 2. Salinity Management – The OCWD uses water from the Santa Ana River (consisting of upstream treated wastewater discharges and stormwater) and imported water (from the Colorado River Aqueduct and the State Water Project) to percolate into the forebay Table 6-5.

area of the Orange County groundwater basin. The treated wastewater discharges and water from the Colorado River are high in TDS, with concentrations over 700 mg/l. Higher TDS water can cause corrosion of plumbing fixtures and water heaters. Normalized costs for more frequent replacement of plumbing and water using fixtures and appliances are estimated to range from $100 to $150 per household each year. Over time, the reverse osmosis-treated product from the GWR System will lower the overall TDS content of the groundwater basin, saving the average household approximately $12.50 per year (or $25/acre-foot, $0.08 per 1,000 gallons). Industries and other large water users might also realize significant savings. From the standpoint of salinity management, the GWR System provides an annual benefit of $16.9 million. 3. Delay/Avoid Ocean Outfall Construction – Implementation of the GWR System will divert up to 100 mgd

Cost Estimate for Phase I of the GWR System

Capital Costs Operation & Maintenance Grant Receipts Interest Power Cost Capacity Utilization

$453.9 Million $26.7 Million/year $89.8 Million 2.6% amortized over 25 years $0.11per kwh 50% Barrier injection 50% Recharge percolation


(4,380 l/s) of peak wastewater flow during Phase I from the Sanitation District’s ocean outfall disposal system. The estimated $175 million cost of a new ocean outfall can be delayed at least 10 years by applying several peak reduction methods, including diverting water to the GWR system instead of discharging to the ocean outfall. Economic Summary The annual cost to implement the GWR System – including capital, OM&R, engineering, administration, and contingencies, at 2.6 percent interest and amortized over a 25-year period – would be approximately $37.1 million. Totaling the avoided costs, the total annual benefits are as shown in Table 6-6. This results in a maximum benefit-to-cost ratio of 1.33 ($49.2/$37.1). Based on this analysis, Orange County Water District and Orange County Sanitation District have decided to move forward with the implementation of this project. The EVWRP and the GWR System exemplify how indirect potable reuse projects, when compared to other water supply and wastewater management options, can offer the greatest benefits for the least cost. The ultimate success of these projects would be attributable to project sponsors reaching out and forming alliances with the full array of beneficiaries. The EVWRP and the GWR System exemplify how indirect potable reuse projects, when compared to other water supply and wastewater management options, can offer the greatest benefits for the least cost. The ultimate success of these projects would be attributable to project sponsors reaching out and forming alliances with the full array of beneficiaries.

Source: WateReuse Association, 1999. Updated by CDM/ OCWD Project Team, 2004.


Impact Fee Development Considerations for Reclaimed Water Projects: Hillsborough County, Florida

Hillsborough County is located on the central-west coast of the State of Florida. The unincorporated area encompasses 931 square miles (2,411 km2), or more than 86 percent of the total county area. Approximately 650,000 residents live in unincorporated Hillsborough County, and most of them are served by various community services provided by the County. The Hillsborough County Water Department is responsible for providing treatment and delivery of potable water, wastewater collection, and treatment and distribution of reclaimed water within unincorporated Hillsborough County. The Department currently saves about 10 mgd (440 l/s) of potable water through reuse. Future expansion of the reclaimed water system is expected to save about 30 mgd (1,315 l/s) of potable water by the year 2020. Florida continues to be a rapidly growing state. To address the need for additional infrastructure, local governments have turned to development impact fees. Development impact fees are charges applied to new development to pay for the construction of new facilities or for the expansion of existing ones to meet these demands. Water and wastewater utilities are no exception. At least half of Florida’s 67 counties use some form of impact fees to pay for expansion of their water and wastewater utility that is necessitated by growth in the community. The following 3 criteria must be met to justify these fees: (1) there must be a reasonable connection between growth from new development and the resultant need for the

Table 6-6.

Total Annual Benefits

Item Orange County Water District (OWCD) Cost Avoidance Salinity Management Orange County Sanitation District (OCSD), Delay in outfall Total Benefits

Total Annual Cost Avoidance (Millions $) $27.40 $16.90 $4.90 $49.20


new service; (2) the fees charged cannot exceed a proportionate share of the cost incurred in accommodating the new users paying the fee; and (3) there must be a reasonable connection between the expenditure of the fees that are collected and the benefits received by the new customers paying the fees. Several years ago, Hillsborough County decided to fund a portion of the cost of new reclaimed water projects through the capacity fee mechanism. It was recognized that the service benefits reclaimed water customers as well as new customers to the system that do not necessarily receive the reclaimed service. Specifically, reclaimed water projects have the unique characteristic of providing capacity in both the water and wastewater components of a traditional utility. The Department’s potable water investment since 1986, when the majority of the debt for the existing system was issued, is approximately $175 million with a corresponding potable water capacity of 54.5 mgd (2,400 l/ s). The level of service prior to potable water conservation benefits derived from using reclaimed water was approximately 350 gpd (1,325 l/d) per Equivalent Residential Connection (ERC). Based on this level of service, the 54.5 mgd (2,400 l/s) potable water capacity would serve 155,714 ERCs. However, since reclaimed water service has been implemented, the Department has been able to reduce the level of service to 300 gpd (1,135 l/d) per ERC. The same 54.5 mgd (2,400 l/s) of capacity is now able to serve 181,667 ERCs with no additional investment in potable water capacity. This equates to 25,953 additional ERCs being served due to reclaimed water use – or a potable water capacity avoidance at the 350-gpd (1,325 l/d) level of service of 9.1 mgd (400 l/s). Assuming a cost of $5.25 per gpd for additional potable water capacity based on desalination treatment, the potable water capacity cost avoided is approximately $47.78 million. The Department has 8 wastewater treatment plants with a total permitted treatment capacity of 48.5 mgd (2,125 l/s). These treatment plants have permitted effluent disposal capacity in the form of a surface-water discharge Table 6-7. Reclaimed Water Impact Fees

for 24 mgd (1,050 l/s). The difference of 24.5 mgd (1,075 l/s) is the effluent disposal benefit obtained from reclaimed water. Using a cost of $2.40 per gpd for either land application or deep-well injection methods for alternate effluent disposal, this results in an effluent disposal cost avoided of approximately $58.8 million. Using these calculations, the total cost avoided for both water and wastewater is $106.58 million. The potable water capacity cost avoided and the effluent disposal cost avoided were each divided by this total cost to determine the allocation of reclaimed water project costs associated with water and wastewater. This resulted in a reclaimed water project cost split of 45 percent to water and 55 percent to wastewater. The current North service area capacity fee is $1,335 for water and $1,815 for wastewater. For the South/Central service area, the current capacity fee is $1,440 for water and $1,970 for wastewater. Table 6-7 provides the percentage of the capacity fees that have been attributed to reclaimed water projects in these service areas.


How Much Does it Cost and Who Pays: A Look at Florida’s Reclaimed Water Rates

Reclaimed water is becoming an increasingly valuable water resource in Florida in terms of groundwater recharge, conservation of potable quality water, and drinking water cost savings to the consumer (since reclaimed water is usually less expensive than drinking water to the consumer). In fact, reuse has become so popular that some utilities have had trouble keeping up with the demand. In order to meet the high demand for reclaimed water, some utilities have used other sources (i.e., groundwater, surface water, etc.) to augment their reclaimed water supply. Others deal with high reclaimed water demand by imposing watering restrictions on reuse customers, and/or limiting or prohibiting new customer connections to the reuse system. Many reclaimed water suppliers used these methods to try to meet demands when the

Service Area North South/Central

Percent of Water Capacity Fee Allocated to Reclaimed Water 8 6

Percent of Wastewater Fee Allocated to Reclaimed Water 29 18


state was faced with a drought, but a few suppliers still struggled. The need to conserve and properly manage reclaimed water as a valuable resource became very clear. In the past, many utilities provided reclaimed water at no cost to the customer or based on a fixed monthly charge, regardless of use. Since the water was free or sold at low flat rates, customers used as much as they wanted, which was usually more than they needed. Now, many utilities are moving towards volume-based charges for reclaimed water service. Although the main intent of charging reuse customers for reclaimed water is to recover the costs associated with reuse facilities, reuse customers that are charged by the gallon for reclaimed water service tend to be more conservative in their use of the water supply. 1999 Florida Reclaimed Water Rates Every year, the Florida Department of Environmental Protection publishes the Reuse Inventory that contains a good deal of useful information regarding water reclamation facilities in Florida, including reuse rates charged by facilities. The 1999 Reuse Inventory (FDEP, 2000) compiles rates under 2 categories, Residential and Non-Residential. A survey based on information from the 1999 Reuse Inventory for 176 reuse systems revealed the following: Non-Residential Category: Forty-five percent of the reuse systems provided reclaimed water free of charge, 33 percent charged by the gallon, about 10 percent charged a flat rate, and 12 percent incorporated the base facility charge and the gallonage charge. Residential Category: Eight percent of the systems surveyed provided reclaimed water free of charge, 12 percent by the gallon, 22 percent charged a flat rate, and about 10 percent utilized the base facility charge and the gallonage charge. (48 percent of the systems surveyed

did not provide residential service.) The average rates associated with each rate type are shown in Table 6-8. According to an AWWA survey, reuse rates are developed in many different ways. Out of 99 facilities surveyed, 19 percent set the rate at a percentage of the potable water rate, 14 percent base the rate on the estimated cost of the reuse service, 24 percent set the rate to promote use, 9 percent base the rate on market analysis, and 33 percent use other methods to develop reuse rates. The survey also revealed what percentages of costs were recovered through reuse rates for these facilities as shown in Table 6-9. Fifty-three percent of 97 facilities surveyed charge a uniform rate for reclaimed water, approximately 6 percent charge inclining block rates, 2 percent charge declining block rates, and 6 percent charge seasonal rates. The other 33 percent used some other type of rate structure (AWWA, 2000). The survey shows that the majority of reuse customers are metered. The average metered rate of 16 surveyed facilities was $1.12/1,000 gallons. In order to determine the relationship between how much reclaimed water a reuse customer used and how much they were charged for the service, the Southwest Florida Water Management District (SWFWMD) conducted a survey of utilities in Pinellas County that provided reclaimed water to residential customers. This survey revealed that residential customers who were charged a flat rate used an average of 1,112 gallons of reclaimed water per day, while residential customers who were charged per 1,000 gallons only used an average of 579 gallons per day (Andrade, 2000). The average metered rate charged by these utilities was $0.61/1000 gallons. The average flat rate charged by these utilities was $9.77/ month. Based on the average usage of 1,112 gallons per day reported for residential customers, this flat rate translates to a metered rate of $0.29/1000 gallons. Source: Coleman and Andrade, 2001

Table 6-8.

Average Rates for Reclaimed Water Service in Florida

Non-Residential Flat Rate 1* Flat Rate 2** Metered Rate Flat Rate with Metered Rate $19.39/month $892,89/month $0.26/1,000 gallons $29.99/month+$0.39/1,000 gallons $6.85/month


Not Applicable $0.39/1,000 gallons $7.05/month+$0.34/1,000 gallons


Table 6-9.

Percent Costs Recovered Through Reuse Rates

Percent of Costs Recovered Under 25 Percent 25 to 50 Percent 51 to 75 Percent 76 to 99 Percent 100 Percent Unknown

Percent of Utilities Recovering Costs 32 5 5 14 13 31


Rate Setting for Industrial Reuse in San Marcos, Texas

The newly expanded San Marcos 9-mgd (395-l/s) advanced tertiary wastewater treatment plant is a state-ofthe-art facility that produces some of the highest quality effluent in the State of Texas. The permit requirements are the toughest the Texas Natural Resources Conservation Commission deploys: 5/5/2/1/6 (BOD5/TSS/NH3/ PO4/DO). Since coming on-line last year, the quality of the effluent has consistently been better than the permit limits require. In this region of the state, the use of groundwater is discouraged and surface water is becoming less available and more costly; therefore, reclaimed water is becoming a marketable commodity. In January 1999,

American National Power approached the City of San Marcos, as well as other cities in the Central Texas area between Austin and San Antonio, with a list of resources required for the power co-generation facility they were to build – The Hays Energy Project (HEP) – in anticipation of the imminent electrical power deregulation in Texas. Principal on the list was a reliable, economical source of both potable and process water, and a means of disposing of their domestic wastewater and process wastewater. The City had no existing wastewater treatment plant effluent customers and no historical basis for setting a rate to charge the HEP for delivering to them basically the City’s entire effluent flow.

Figure 6-2.

Comparison of Rate Basis for San Marcos Reuse Water


In considering rates to this industrial customer, the City of San Marcos investigated both the actual cost of producing and delivering reclaimed water as well as the market value of reclaimed water. By including only those facilities over and above what was required for normal wastewater treatment and disposal, the actual cost of delivering reclaimed water was determined to be between $0.25 to $0.54/1,000 gallons. A review of the existing costs of alternate suppliers of water in the region was then conducted to define the market value of reclaimed water to the industrial customers. This investigation included reuse rates charged elsewhere in the state and determined that the cost of alternate water supplies might range from $0.40 to $0.90/1,000 gallons. The results of this investigation are summarized in Figure 6-2. Based on the results of this investigation, the City was able to consider reclaimed water as a commodity and set the charges as a function of available supplies, the demand for water and the benefits of the service. Through this process, the City established a charge of $0.69/1,000 gallon as shown in Figure 6-2. Source: Longoria et al., 2000.

76th Annual Florida Water Resources Conference, Jacksonville, Florida. Collins, J.M. 2000. “The Price of Reclaimed Water in Reno, Nevada,” 2000 Water Reuse Conference Proceedings, San Antonio, Texas. Farabee, D.L., P.S. Wilson, J. Saputo. 2002. “How Volume Pricing Affects Residential Reuse Demands,” WEFTEC 2002, Proceedings of the 75th Annual Conference and Exposition, Chicago, Illinois. Florida Department of Environmental Protection. 2002.2001 Reuse Inventory, Tallahassee, Florida. Florida Department of Environmental Protection. 1999 Reuse Inventory. Tallahassee, Florida: Florida Department of Environmental Protection. 2000. Gray, B. P., M. Craig, B.E. Hemken. 1996 “Integrated Water Resources Planning for Scottsdale, Arizona,” Water Reuse Conference Proceedings, American Water Works Association, Denver, Colorado. Gorrie, J.M., V.P. Going, M.P. Smith and J. Jeffers. 2003. “Impact Fee Development Considerations for Reclaimed Water Projects,” 2003 FWRC Proceedings, Tampa, Florida. Lindow, D., J. Newby. 1998. “Customized Cost-Benefit Analysis for Recycled Water Customers,” Water Reuse Conference Proceedings, American Water Works Association, Denver, Colorado. Longoria, R.R., D.W. Sloan, S.M. Jenkins. 2000. “Rate Setting for Industrial Reuse in San Marcos, Texas,” 2000 Water Reuse Conference Proceedings, San Antonio, Texas. Martinez, P.R. 2000. “San Antonio Water System Recycled Water Program: An Alternative Water Supply – Short Term Management Resources,” 2000 Water Reuse Conference Proceedings, San Antonio, Texas. Sheikh, B., E. Rosenblum, S. Kosower, E. Hartling.1998. “Accounting for the Benefit of Water Reuse,” Water Reuse Conference Proceedings, American Water Works Association, Denver, Colorado. Southwest Florida Water Management District. Annual Alternative Water Supply Report FY 2003. Southwest Florida Water Management District, 2003, Brooksville, Florida.



Andrade, Anthony. 2000. “Average Reclaimed Water Flows for Residential Customers in Pinellas County.” Brooksville, FL: Southwest Florida Water Management District. American Water Works Association. 2000. “AWWA/WEF Water Reuse Rates and Charges Survey Report.” American Water Works Association. Personal Communication with Dennis Cafaro, 2003. California State Water Resources Control Board. 1991. Water Recycling 2000: California’s Plan for the Future. Office of Water Recycling, Sacramento, California. Camp Dresser & McKee Inc. and Orange County Water District, 2004. Project team consists of Richard Corneille, Robert Chalmers, and Mike Marcus. City Of Los Angeles Department of Water and Power Urban Water Management Plan Fiscal Year 1997-1998 Annual Update – page 19. Coleman, L.W., A. Andrade. 2001. “How Much Does it Cost and Who Pays: A Look at Florida’s Reclaimed Water Rates,” Technical Program and Proceedings of the


Washington State Department of Ecology. Focus Sheets. August 2001. Water Environment Research Foundation. 2001. Management Practices for Nonpotable Water Reuse. Project 97IRM-6. Alexandria, Virginia. WateReuse Association. 1999. “Use of Recycled Water to Augment Potable Supplies: An Economic Perspective.”


CHAPTER 7 Public Involvement Programs
In the years since this manual was first developed, the world has seen ever-increasing demands for water, often from competing interests, and often in the face of declining water supplies. As a result, water quality and quantity have become important public topics in many arenas, and regulatory agencies often require some level of stakeholder involvement in water management decisions. This is strikingly different from the past when members of the public were often informed about projects only after final decisions had been made. Today, responsible leaders recognize the need to incorporate public values with science, technology, and legal aspects to create real, workable solutions tailored to meet specific needs. In the area of water reuse, the opportunities for meaningful public involvement are many. This chapter provides an overview of the key elements of public planning, as well as several case studies illustrating public involvement and/or participation approaches. In general, effective public participation programs invite two-way communication, provide education, and ask for meaningful input as the reuse program is developed and refined. Depending on the project, public involvement can involve limited contact with a number of specific users, or can be expanded to include the formation of a formal advisory committee or task force. Often, public information efforts begin by targeting the most impacted stakeholders. Over time, as an early education base is built among stakeholders, the education effort then broadens to include the public at large. Regardless of the audience, all public involvement efforts are geared to help ensure that adoption of a selected water reuse program will fulfill real user needs and generally recognized community goals including public health, safety, and program cost. The term, “two-way communications flow” cannot be too highly emphasized. In addition to building community support for a reuse program, public participation can also provide valuable community-specific information to the reuse planners. Citizens have legitimate concerns, quite often reflecting their knowledge of detailed technical information. In reuse planning, especially, where one sector of “the public” comprises potential users of reclaimed water, this point is critical. Potential users generally know what flow and quality of reclaimed water are acceptable for their applications.


Why Public Participation?

Public involvement or participation programs work to identify key audiences and specific community issues at a very early stage, offering information and opportunities for input in a clear, understandable way. Effective public involvement begins at the earliest planning stage and lasts through implementation and beyond. Public participation begins with having a clear understanding of the water reuse options available to the community. Once an understanding of possible alternatives is developed, a list of stakeholders, including possible users, can be identified and early public contacts may begin. Why begin contacting stakeholders before a plan is in place? These citizen stakeholders can provide early indications regarding which reuse program will be best accepted on a community-wide level. Beyond that, informed citizens can help identify and resolve potential problems before they occur and develop alternatives that may work more effectively for the community.


Informed Constituency

By taking time during the planning stages to meet with citizens, communities will have a much greater opportunity to develop a successful reuse program. Many citizens may have a pre-conceived notion about reclaimed water and its benefits. It is important to identify each stakeholder’s issues and to address questions and concerns in a clear, matter-of-fact way. This two-way dialogue will lead to informed input regarding reuse alternatives.


A public participation program can build, over time, an informed constituency that is comfortable with the concept of reuse, knowledgeable about the issues involved in reclamation/reuse, and supportive of program implementation. Ideally, citizens who have taken part in the planning process will be effective proponents of the selected plans. Having educated themselves on the issues involved in adopting reclamation and reuse, they will also understand how various interests have been accommodated in the final plan. Their understanding of the decision-making process will, in turn, be communicated to larger interest groups – neighborhood residents, clubs, and municipal agencies – of which they are a part. Indeed the potential reuse customer who is enthusiastic about the prospect of receiving service may become one of the most effective means of generating support for a program. This is certainly true with the urban reuse programs in St. Petersburg and Venice, Florida. In these communities, construction of distribution lines is contingent on the voluntary participation of a percentage of customers within a given area. In other communities where reuse has not been introduced in any form, the focus may begin with very small, specific audiences. For instance, a community may work closely with golf course owners and superintendents to introduce reuse water as a resource to keep the golf course in prime condition, even at times when other water supplies are low. This small, informed constituency can then provide the community with a lead-in to other reclaimed water options in the future. Golf course superintendents spread the word informally, and, as golfers see the benefits, the earliest of education campaigns has subtly begun. Later, the same community may choose to introduce an urban system, offering reclaimed water for irrigation use. Since many reuse programs may ultimately require a public referendum to approve a bond issue for funding reuse system capital improvements, diligently soliciting community viewpoints and addressing any concerns early in the planning process can be invaluable in garnering support. Public involvement early in the planning process, even as alternatives are beginning to be identified, allows ample time for the dissemination and acceptance of new ideas among the constituents. Public involvement can even expedite a reuse program by uncovering any opposition early enough to adequately address citizen concerns and perhaps modify the program to better fit the community.

lics” with differing interests, motivations, and approaches to policy issues. For example, in discussing public participation for wastewater facilities and reuse planning the following publics may be identified: general public, potential users, environmental groups, special interest groups, home owners associations, regulators and/or regulating agencies, educational institutions, political leaders, and business/academic/community leaders. In an agricultural area, there may be another different set of publics including farmers. For example, several government agencies in California held a Reuse Summit in 1994, at which they endorsed the creation of the public outreach effort by creating the following mission statement (Sheikh et al., 1996): “To activate community support for water recycling through an outreach program of educating and informing target audiences about the values and benefits of recycled water.” During that summit they also identified 8 public audiences: Local Elected Officials, Regulatory Agency Staff, General Public, Environmental Community, City Planning Staffs, Agricultural Community, Schools, and Newspaper Editorial Boards. From the outset of reuse planning, informal consultation with members of each of the groups comprising “the public”, and formal presentations before them, should both support the development of a sound base of local water reuse information and, simultaneously, build a coalition that can effectively advocate reuse in the community. Keeping in mind that different groups have different interests at stake, each presentation should be tailored to the special needs and interests of the audience. If a reuse program truly has minimal impact on the general public, limited public involvement may be appropriate. For example, use of reclaimed water for industrial cooling and processing – with no significant capital improvements required of the municipality – may require support only from regulatory, technical, and health experts, as well as representatives from the prospective user and its employees. Reuse for pastureland irrigation in isolated areas might be another example warranting only limited public participation.


Overview of Public Perceptions


Defining the “Public”

Many contemporary analyses of public involvement define “the public” as comprising various subsets of “pub-

One of the most tried and true methods of determining the public’s perception of reuse programs is surveys. Surveys can determine whether or not there will be a large enough consumer base to sustain a program, if the pro-


gram will be favorable enough to progress to the conceptual and design stage, and the overall success of the project after implementation. The following projects highlight different survey strategies and results across the nation.


Clark County Sanitation District Water Reclamation Opinion Surveys


Residential and Commercial Reuse in Tampa, Florida

A survey done by the City of Tampa for its residential reuse project included a direct mailing and public opinion survey. Information was sent to 15,500 potable water customers in the conceptual project area. Out of the pool of potential reuse customers, 84 percent of the residential users and 94 percent of the commercial users in the South Tampa area thought that reclaimed water was safe for residential and commercial landscape irrigation. Of the same group, 84 percent of the residential responders and 90 percent of the commercial responders replied that the project was appealing. The responses met the design criteria of 90 percent participation (Grosh et al., 2002).

Clark County (Las Vegas, Nevada) conducted a series of 4 different surveys. The surveys included a face-toface intercept survey at the Silver Bowl Park, a direct mail survey with local residents in the Silver Bowl Park area, a direct mail survey to local residents in the Desert Breeze Park vicinity, and face-to-face intercepts with attendees of the EcoJam Earth Day Event. A total of 883 persons participated in the survey (Alpha Communications Inc., 2001). The majority (63.8 to 90.1 percent) of the responses were very positive, replying that the “…overall benefits of reclaimed water usage are very beneficial.” There was a small minority who had concerns with “…environmental safety, bacteria, or germ build-up and general health risks to children” (Alpha Communications Inc., 2001). Figure 7-3 shows a graphical representation of the average public opinion responses from the 4 surveys regarding reuse for 4 different uses: golf course irrigation, park irrigation, industrial cooling, and decorative water features. Another portion of the survey asked if there were any benefits of using reclaimed water at park facilities. Table 7-1 lists the responses. There is no question that the public’s enthusiasm for reuse (as noted in the cited studies) could reflect the hypothetical conditions set up by the survey questions and interviews used rather than signify a genuine willingness to endorse local funding of real programs that involve distribution of reclaimed water for nonpotable use in their neighborhood. Survey results do indicate, however, that, at least intellectually, “the public” is receptive to use of reclaimed water in well thought out programs. The results also support conclusions that this initial acceptance hinges in large measure on:


A Survey of WWTP Operators and Managers

A study done by Hall and Rubin in 2002 surveyed 50 wastewater operators and managers. Seventy percent of the responders stated that they believed that reuse would be an important part of their operation in 5 years. The majority (66 percent) thought that water reuse should be considered as an element of all water and wastewater expansion facility permits. Ninety percent wanted funding agencies to consider financial incentives to encourage more water reuse. Table 7-1 lists the survey results (in percentages) to the inquiry for potential use alternatives for reclaimed water.


Public Opinion in San Francisco, California

The City of San Francisco, California, surveyed the general public to measure public acceptance of a proposed reclaimed water project. Figures 7-1 and 7-2 graphically demonstrate the responses that were collected. The overall majority strongly felt that reclaimed water was beneficial. Figure 7-2 shows that the responders felt positively about all of the proposed uses of reclaimed water: fire fighting, irrigation of golf courses and parks, street cleaning, toilet flushing, and drought protection.

The public’s awareness of local water supply problems and perception of reclaimed water as having a place in the overall water supply allocation scheme ter and how it would be used

„ Public understanding of the quality of reclaimed wa-


Confidence in local management of the public utilities and in local application of modern technology ered involve minimal risk of accidental personal exposure

„ Assurance that the reuse applications being consid-


Table 7-1.

Positive and Negative Responses to Potential Alternatives for Reclaimed Water
Use Yes 84 82 85 74 89 82 30 76 90 82 67 80 84 56 87 78 84 15 18 40 No 16 18 15 26 11 18 70 24 10 18 33 20 16 44 13 22 16 85 82 60

Irrigation of Athletic Fields Irrigation of Office Parks and Business Campuses Irrigation of Highway Right-of-way Residential Landscape Irrigation and Maintenance Golf Course Irrigation Irrigation of Agricultural Crops Irrigation of Crops for Direct Human Consumption Vehicle Wash Water Concrete Production Dust Control Stream Augmentation Toilet Flushing Fire Protection Ornamental Ponds/Fountains Street Cleaning Industrial Process Water Wetland Creation Pools/Spas Potable Reuse – Direct Potable Reuse – Indirect

Adapted from Hall and Rubin, 2002


Involving the Public in Reuse Planning

Even where water reclamation is common, there is a need to establish a flow of information to and from potential reuse customers, so that they can have a clear understanding of the program and provide input regarding their needs and concerns. Equally important is the need to address these concerns and answer any questions in a timely manner. This can help assure the public that their issues are being heard and that reuse planners are being forthcoming in their efforts. Probably the most important step in encouraging the public acceptance is to establish and communicate the expected project benefits. If the project is intended to

extend water resources, then preliminary studies should address how much water will be made available through reclamation and compare the costs to those needed to develop other potable water sources. If reclamation costs are not competitive, then overriding non-economic issues must exist to equalize the value of the 2 sources. When reclamation is considered for environmental reasons, such as to reduce or eliminate surface water discharge, then the selected reuse alternative must also be competitive with other disposal options. Above all, the public must be aware of and understand all of the benefits. However, most potential reuse programs invoice choices among systems with widely different economical and environmental impacts, which are of varying degrees of


Figure 7-1.
100 90 80 70 60 50 40 30 20 10 0

Public Beliefs and Opinions

Agree Disagree

Reclaimed Wasteful to Water Will Help Discharge in Dry Years Reclaimed Water into the Ocean

Reclaimed Reclaimed Government Water Will Water Will Will Make Save Money Maintain Lake Reclaimed in Long Run Water Levels Water Safe

Government Reclaimed Reclaimed Cannot Be Water Will Cost Water is Trusted With Too Much Unsafe Reclaimed

City Doesn’t Need Extra Water

Adapted from Filice 1996

Figure 7-2.
100 90 80 70 60 50 40 30 20 10 0

Support of Recycled Water Program Activities

Support Oppose

Fight Fires

Water Parks & Golf Courses

Clean Streets

Flush Toilets in Buildings

Reduce Rationing (During Droughts)

Adapted from Filice 1996


Figure 7-3.
90 80 70 60
% Response

Survey Results for Different Reuse

Golf Courses Parks Industrial Cooling Water Features

50 40 30 20 10 0 Very Beneficial Some Benefit


Little Benefit

Not at all Beneficial

Data Source: Alpha Communications 2001

importance to many segments of the public. That is why development of the expected project benefits is so important because once they are firmly established, they become the plants of a public information program – the “why” the program is necessary and desirable. Without such validation, reclamation programs will be unable to withstand public scrutiny and the likelihood of project failure increases. In addition, only after the “why” is established can the “who” and “how” in public involvement truly be determined.

tives. If additional facts or studies are needed, consider beginning them in the earliest stages so that additional scientific data can be made available later in the process. Unanswered questions can damage the credibility of the program effort.
„ Create a master list of stakeholders, including agen-


General Requirements for Public Participation

cies, departments, elected officials, potential customers, and others who will be impacted in some way. It might be helpful to identify the level of interest different individuals and groups will have in the reuse planning process. Begin public outreach to specific target audiences in the form of informal meetings involving direct contact, limiting the number invited at any one time so that individual discussion is more easily accomplished Determine whether a task force or advisory committee is needed. If so, take steps to formally advertise and be sure to include representatives from the target audience groups. Plan a schedule and target date for reaching consensus on reuse alternatives; then plan well-prepared meetings that invite two-way communications. Bring in outside experts, such as scientists, to answer questions when needed.

Figure 7-4 provides a flow chart of a public participation program for water reuse system planning. The following items suggest an example approach that a community might consider in developing a reuse program. Note that information tools will vary depending upon how broad or involved an information program is needed.


Determine, internally, the community’s reuse goals and the associated options and/or alternatives to be further considered. Identify any scientific/technical facts that exist, or are needed, to help explain the issues and alterna-



Figure 7-4.

Public Participation Program for Water Reuse System Planning

Specific Users Survey

General Survey

Alternatives Identification & Evaluation

Plan of Study

Plan Selection

Project Implementation

Preliminary Investigation

CustomerSpecific Workshops

Public Notification/ Involvement

Customer-Specific Information Program(s)

Target Audience

Broader Public Group

Table 7-2.

Survey Results for Different Reuse
Tools News media, editorial boards, program web site, traveling exhibits, brochures, educational videos, school programs, open houses Neighborhood meetings, speeches and presentations to citizen/stakeholder groups, direct mail letters and surveys, program “hotlines” for answering information or managing construction complaints Public workshops, public meetings, presentations to elected bodies, public hearings, advisory committees, special task forces

Purpose Communitywide Education/Information Direct Stakeholder or Citizen Contact

Formalized Process

From the task force or advisory committee, the community should be able to identify public issues that need further attention, and determine which additional public information tools will be needed. Table 7-2 outlines a number of public information tools that can be used in the public participation process. Once the issues are identified and public reaction is anticipated, the following tools may be useful in conveying information to the broader public:

eral distribution survey may be helpful in identifying level of interest, potential customers, and any initial concerns that the population might have. Where specific concerns are identified, later public information efforts can be tailored to address them. These tailored efforts could include participation by other public agencies that can provide information on water reuse and regulatory requirements, informal discussions with some potential users to determine interest or fill data gaps, and initial background reports to appropriate local decision- making bodies.

Citizen survey. Can be conducted via direct mail or telephone and might be accompanied by media releases to help increase the number of surveys returned or calls answered. In the early stages, a gen-

As the program progresses to alternative identification and evaluation, another survey might be considered. This survey could help confirm earlier re-


sults, monitor the effectiveness of the ongoing education program, or target specific users. Note that the percentage of citizens who take the time to participate in a survey varies widely from one community to another. This should not be the only tool relied upon in gathering input.
„ Open houses. Advertise periodic public open houses

Once a reuse program has been determined, additional public information efforts will be needed throughout the implementation phase, including notification to citizens prior to construction occurring near their home or business. Then, as the reuse program goes on-line, additional media relations and direct mailings will be needed. In the case of urban reuse, this will include information to help homeowners through the connection process. The City of Tampa’s residential reclaimed water project (Florida) is one example of a successful comprehensive public participation program. The City used the services of Roberts Communication to conduct a targeted public education program, which included the following elements (Grosh et al., 2002):
„ Opinion leader interviews „

where information is made available and knowledgeable people are on hand to answer questions. Maps, displays, and brief slide demonstrations are all useful open house tools.

Program website. Increasingly, citizens are turning to websites as important information sources. Such a website can be purely informational or it can invite citizens to ask questions. The website should be updated on a regular basis and can include: its own survey or results of a citizen survey, answers to frequently asked questions, information regarding other successful programs in nearby communities, or a slideshow-style presentation that outlines the program goals and alternatives being considered. it can be very helpful to spend extra time with reporters who will be covering the topic on a regular basis, providing added background data, plant tours, and informal updates at appropriate times. This helps to provide accurate, balanced reports. The media can also be helpful in making survey data known, and in posting maps of construction areas once program implementation is underway.

Public opinion survey

„ Speakers bureau „

Direct mail to potential customers letters

„ Media relations. In addition to project news releases,

„ Newsletter article for homeowner association news-

Public Advisory Groups or Task Forces

„ Direct mail updates or occasional newspaper inserts.

These updates allow the community to address questions or issues - not relying specifically on a media report.

Briefings for government officials. Because water reclamation programs often end up with a vote by a city council, county commission, or other elected body, it is vital that each elected official be wellinformed throughout the reuse planning process. Therefore, informal briefings for individual officials can be an invaluable tool. These briefings are often conducted prior to public workshops and formal votes, and allow questions to be answered in advance of a larger, public setting. a tour of an existing project that is similar to the one proposed can be an especially useful tool in providing information to key stakeholders, such as an advisory committee, elected body, or the media.

If the scope or potential scope of the reuse program warrants (e.g., reclaimed water may be distributed to several users or types of users, or for a more controversial use), a public advisory group or task force can be formed to assist in defining system features and resolving problem areas. In its regulations for full-scale public participation programs, EPA requires that such group membership contain “substantially equivalent” representation from the private (non-interested), organized, representative, and affected segments of the public. It is recommended that, for reuse planning, group membership provide representation from potential users and their employees, interest groups, neighborhood residents, other public agencies, and citizens with specialized expertise in areas (such as public health) that pertain directly to reclamation/reuse. The advantage of an advisory group or task force is that it offers an opportunity to truly educate a core group that may later become unofficial “spokespersons” for the project. For such a group to be successful, members must see that their input is being put to meaningful use. Depending upon the community need, either an advisory committee or task force may be appropriate. Advisory committees are generally formed for an indeterminate period to continuously provide input regard-

„ Plant or project tours. During the education process,


ing issues related to the topic. So, if an advisory committee is formed for reuse water, the committee may be kept as a recommending body to city council, county commission, or other elected body, regarding all future reclaimed water projects or issues. Often, members of the advisory group are designated to serve 2-year terms. With the development of a task force, the objectives are clearly defined and the task force disbands once the objectives have been met. Often, a task force can be a better short-term solution. Whether a community chooses a task force or advisory committee, it is very important to take steps to institutionalize the group and its activities so that its efforts are formally recognized as meaningful by the elected body. This group can effectively focus on the task at hand—planning and implementation of a reuse program in which the legitimate interests of various sectors of the public have been fully considered and addressed. In order to achieve this, the proposed formation of the advisory group or task force should be publicized to solicit recommendations for, and expression of interest in, membership. Often, the community and its leadership will be aware of candidates who would be ideal to fulfill this role. Whether a short-lived task force or a longer-term advisory committee, the group’s responsibilities should be well-defined. Its meetings should be open to the public at times and places announced in advance. Interpretive meeting minutes should be kept and made available to the public. During an initial meeting, the group’s members should designate a single individual who can serve as a contact point for the news media. The group should fully recognize its shared responsibility for developing a sound reuse program that can serve both user requirements and community objectives. In subsequent public meetings, the group will assert its combined role as a source of information representing numerous interests, and an advocate of the reuse program as it gains definition. Public Participation Coordinator

larger community, should be thoroughly informed of the reuse planning process, be objective in presenting information, and have the ‘clout’ necessary to communicate and get fast response on issues or problems raised by citizens involved in the process. To accomplish this goal, many communities involved in urban and agricultural reuse have created a dedicated reuse coordinator position. The responsibilities of such a position will vary according to specific conditions and preferences of a given municipality. In many programs, the reuse coordinator is part of the wastewater treatment department. However, the position can be associated with the water system, or independent of either utility.


Specific Customer Needs

As alternatives for water reuse are being considered, the customers associated with each alternative should be clearly identified, and then the needs of these customers must be ascertained and addressed. In the past, failure to take this step has resulted in costly and disruptive delays to reclamation projects. Early involvement of citizen stakeholders is a key to program success and is based on tailoring a program to the specific user type and type of reuse system. Urban Systems

In urban reuse programs, the customer base may consist of literally thousands of individuals who may be reached through the local media, publicly advertised workshops, open houses, or neighborhood meetings. Identification of homeowner associations and civic organizations may allow for presentations to a larger number of potential customers at a single time. The Monterey Regional Water Pollution Control Agency (MRWPCA) is one example of a public information program that reaches a large urban audience. It has an active school education program with classroom demonstrations to about 2,300 children each year. Booths at the County Fair and other local events reach another 7,500 people. Speeches to civic and service groups reach another 900 people. Together with the 800 people who tour the water reclamation plant each year, 5 percent of the service area population is being educated each year. Bimonthly billing inserts add to the local understanding and appreciation of water reclamation. Agricultural Systems

EPA regulations for full-scale public participation programs require appointment of a public participation coordinator – an individual skilled in developing, publicizing, and conducting informal briefings and work sessions as well as formal presentations for various community groups. The appointment of a public participation coordinator helps ensure that one accurate source of information is available, and that individuals who show interest are given an opportunity to provide meaningful input. Such a person, whether an agency staff member, advisory group member or specialist engaged from the

In agricultural reuse programs, the issues of concern may differ from those of the urban customer. In such pro-


grams, the user is concerned with the suitability of the reclaimed water for the intended crop. Water quality issues that are of minor importance in residential irrigation may be of significant importance for agricultural production. For example, nitrogen in reclaimed water is generally considered a benefit in turf and landscape irrigation. However, as noted in the Sonoma Case Study in Chapter 3, the nitrogen in agricultural reclaimed water could result in excessive foliage growth at the expense of fruit production. Similarly, while turf grass and many ornamental plants may not be harmed by elevated chlorides, the same chloride levels may delay crop maturation and affect the product marketability, as occurred in the strawberry irrigation study for the Irvine Ranch Water District discussed in Section 3.4. For these reasons and others, it is necessary to modify the public participation approach used for the urban customer when developing an agricultural program. Agencies traditionally associated with agricultural activities can provide an invaluable source of technical information and means of transmitting information to the potential user. Local agricultural extension agents may prove to be the most important constituency to communicate as to the benefits of reclamation to the agricultural community. The agents will likely know most, if not all, of the major agricultural sites in the area. In addition, they will be familiar with the critical water quality and quantity issues facing the local agricultural market. Finally, the local farmers usually see the extension office as a reliable source of information and are likely to seek their opinion on issues of concern, as might be the case with new reclamation projects. The local extension agent will be able to discuss the issues with local farmers and hopefully endorse the project if they are familiar with the concept of reuse. The local soils conservation service may also prove an important target of a preliminary information program. Lack of endorsement from these agencies can hinder the implementation of agricultural reclamation. Reclaimed Water for Potable Purposes

Regulatory agencies, health departments, and other health and safety-related groups will be key audiences throughout the process. These are groups the public turns to for answers; therefore, it is very important to develop strong working relationships. Representatives from local agencies are also most likely to understand the issues that need to be addressed and can provide meaningful input regarding reuse options. Endorsement from these agencies is critical to program acceptance by the public.


Agency Communication

As noted in Chapters 4 and 5, the implementation of wastewater reclamation projects may be subject to review and approval by numerous state and local regulatory agencies. In locations where such projects are common, the procedures for agency review may be well-established. Where reclamation is just starting, formal review procedures may not exist. In either case, establishing communication with these agencies early in the project is as important as addressing the needs of the potential customers. Early meetings may serve as an introduction or may involve detailed discussions of the permitability of a given project. As with all other types of stakeholders, the proposed project must be understood and endorsed by the permitting agencies. It may also be appropriate to contact other agencies that may still become involved with a public education program. In fact, early coordination with key agencies, such as a community health department, is an important consideration for a couple of reasons. First, the agency may not be well-informed about the community’s reuse goals. Early discussions can help to answer questions and identify issues at a time when the issues can most easily be addressed. Second, because the public often turns to these agencies for information, early meetings will help to ensure that citizens receive accurate, consistent answers. If a citizen were to ask one agency a question and receive a different answer than the community representative gave, credibility of the program can be undermined. Where multiple departments in the same agency are involved, direct communication with all concerned departments will ensure coordination. It is worthwhile to establish a master list of the appropriate agencies and departments that will be copied on status reports and periodically asked to attend review meetings. And while this communication will be beneficial in developing any reclamation project, it will be critical when specific regulatory guidance on a proposed project does not exist. Such a condition is most likely to occur in states lacking detailed regulations or in states with very restrictive regulations that discourage reuse projects.

While “reuse” of water has occurred naturally over the ages, the concept of treating wastewater to a level that is acceptable for drinking is the most difficult type of water reuse to gain public acceptance. In such cases public health and safety issues are of utmost importance and citizen questions will need to be fully addressed. Therefore, a comprehensive public participation effort will be required, initially focusing on the water problems to be addressed, and then turning to a thorough look at possible solutions.



Public Information Through Implementation

use has been in place for more than 10 years, the City launched an education campaign gently reminding citizens to conserve.

No matter the type of reclaimed water project, some level of construction will be involved at the implementation stage. Citizens who may not have had an opinion prior to construction could become negative if the process does not go smoothly. This can be especially challenging in urban reuse programs when citizen “disruptions” are more visible. Whenever possible, minimal disruption to sidewalks and driveways should be planned, along with a speedy restoration effort. It will be worthwhile for the community to have a formal construction complaint process in place that offers one phone number to call regarding problems, and a tracking system that documents how quickly complaints are resolved. Public information regarding construction activities can be made available through the local media. The community will also need an information program regarding connections to the system, with emphasis on making the process as simple as possible for each customer.


Case Studies
Accepting Produce Grown with Reclaimed Water: Monterey, California

For many years some vegetables and fruits have been grown in foreign countries with reclaimed water and then sold in the U.S. This practice suggests acceptance on the part of the distributors and consumers. In Orange County, California, the Irvine Company has been furrow irrigating broccoli, celery, and sweet corn with reclaimed water for over 20 years. In 1983, as part of the Monterey Wastewater Reclamation Study for Agriculture (see description in Section 3.8), individuals involved with produce distribution were interviewed regarding the use of reclaimed water for vegetable irrigation. One hundred and forty-four interviews were conducted with:


Promoting Successes

In communities where the use of reclaimed water is new, short-term project successes can become a strong selling point for later, larger programs. Such is the case with communities that may begin an urban program by using reclaimed water in highly visible public medians. Citizens who drive pass these medians are likely to note improvements over time and see “reclaimed water” signs posted at the site. Over time, as a reuse program becomes more established, the public information specialists will need to look for other opportunities to talk about how the program is helping the community. These follow-up information efforts provide an important role in making reuse water a long-term solution for the community. Reclaimed water has been actively and successfully used in urban applications for more than 30 years. These long-term successes have helped to encourage more and more communities to make use of this resource. As citizens have grown to accept and embrace the use of reclaimed water, a new need for education has arisen because the supply of reclaimed water is limited and should not be wastefully used any more than potable water should not be over-used. The problem of reclaimed water over-use seems to be especially true in communities that do not have metering systems to track the specific amount of water used. Metering systems, and a sliding scale for payment according to the amount used, are examples of approaches that some communities use to encourage conservative use of the reclaimed water. In Cape Coral, Florida, where urban re-

Brokers and receivers at terminal markets throughout the U.S. and Canada Buyers for major cooperative wholesalers in principal cities Buyers, merchandisers, and store managers with small, medium, and large chains



The primary focus of the interviews was the need or desire to label produce grown with reclaimed water. The results are given in Table 7-3. The responses indicated the product would be accepted, and that labels would not be considered necessary. According to federal, state, and local agency staff, the source of the water used for irrigation was not subject to labeling requirements. Produce trade members indicated labeling would only be desirable if it added value to the product. Buyers stated that good appearance of the product was foremost. An abbreviated update of the 1983 survey was conducted in 1995 and led to these same conclusions. Since 1998, the Monterey Regional Water Pollution Control Agency (MRWPCA) has been providing reclaimed water for nearly 12,000 acres (4,900 hectares) of vegetables and strawberries. Growers, especially those with a world known brand, are reluctant to advertise the source of water used on their crops. They believe the water is as


Table 7-3.

Trade Reactions and Expectations Regarding Produce Grown with Reclaimed Water

Reaction or Expectation Would Carry Would Not Carry Don’t Know TOTAL Would Not Expect it to be Labeled Would Expect it to be Labeled Don’t Know TOTAL

Respondents Knowledgeable About Reclaimed Water 64% 20% 16% 100% 68% 20% 12% 100%

Respondents Not Aware of Reclaimed Water 50% 25% 25% 100% 67% 25% 8% 100%

Total Number of Respondents=68 Source: Monterey Regional Water Pollution Control Agency, 2002

good as or better than other irrigation water but are concerned with perception issues. Consequently, 3 approaches are being followed to address these concerns: operating the treatment plant beyond the regulatory requirements, low profile education of local residents, and planning for real or perceived problems with the produce. MRWPCA strives to meet Title 22 requirements (<2 NTU, >5 ppm chlorine residual, <23 MPN max.) when the water enters the distribution system. This is usually 1 day after being held in an open storage pond following treatment. During the peak growing season, chlorine residual is maintained in the water until it is applied to the crops. The storage pond is sampled for fecal coliform, emerging pathogens, Clostridium, and priority pollutants. All the results are shared with the growers via the MRWPCA’s website ( and through monthly grower meetings. MRWPCA has an active school education program with classroom demonstrations to about 2,300 children each year. Booths at the county fair and other local events reach another 7,500 people. Speeches to civic and service groups reach another 900. Along with 800 people coming to tour the water reclamation plant each year, 5 percent of the service area population is being educated each year. Bimonthly billing inserts add to the local understanding and appreciation of water reclamation. The Water Quality and Operations Committee is a group consisting of project growers, the county health department, and the reclaimed water purveyors. It meets monthly and decides policy issues for the project. That group hired a public relations firm to plan for a crisis, and a crisis communication manual was prepared. The committee is

editing the manual, continuing to prepare for different possible scenarios, and preparing to train members on how to deal with the press. The growers are still concerned about perception issues, but are confident that they have prepared for most possibilities.


Water Independence in Cape Coral An Implementation Update in 2003

The City of Cape Coral, Florida, is one of the fastest growing communities in the country. At 33 years old, this southwest Florida community has a year-round population of more than 113,000 people. However, like many Florida communities, the population fluctuates with more than 18,000 additional residents in the winter months. What makes the City truly unique is its vast developerplanned canal system, with platted lots throughout the community. City planners knew well in advance that they would eventually need to supply water to more than 400,000 residents. Water supply concerns, coupled with a need to find an acceptable method for ultimately disposing of 42 mgd of wastewater effluent, prompted the City to develop a program called, “Water Independence in Cape Coral” (WICC). WICC includes a unique dual-water system designed to provide potable water through one set of pipes and secondary, irrigation water through a second set of pipes. This secondary water would be provided through reclaimed water and freshwater canals. Implementation of WICC did not come easy. The WICC master plan was prepared, presented, and adopted by the City with relatively little interest from the public. However, when attempts were made to move forward with


Phase 1 (issuance of special property assessment notices), some members of the public became very vocal and were successful in delaying the project. From the time the City committed to proceed, it took 6.5 years to start up Phase 1. Table 7-4 lists the chronology of the WICC implementation and highlights the challenges faced by the City in moving forward. The City began using the secondary water system in 1992. Had a public awareness campaign been launched in the early years, it could have addressed citizen concerns prior to finalizing the special assessment program. Cape Coral’s experience provides a valuable lesson to other communities introducing reuse water. During the first 8 years of using secondary water, Cape Coral was able to conserve more than 4 billion gallons (15 million m3) of potable water that would previously have been used for irrigation purposes. The system works by pumping reclaimed water from storage tanks to the distribution system. Five canal pump stations transfer surface water from freshwater canals, as needed. Variable speed effluent pumps respond to varying customer de-

mands. The secondary water is treated and filtered before going into the distribution system. In 2002, the City successfully used secondary water to irrigate more than 15 miles (24 km) of landscaped medians. Other benefits have included the availability of year round irrigation at a reasonable price to customers, the deferred expansion of a City wellfield, the deferred construction of a second reverse osmosis water treatment facility by a number of years, and nearly zero discharge of effluent into the nearby Caloosahatchee River. As Cape Coral residents came to accept secondary water as an irrigation source, the City found a need to launch an entirely different kind of education campaign. In response to “over-watering” by some customers and concerns by regulatory agencies, the City began to enforce limited watering days and times, just as with potable water. The City’s new education campaign underscored the message that secondary water should be recognized as a resource, not a “disposal issue.” The City created a friendly “Cape Coral Irrigator,” using a smiling alligator,

Table 7-4.

Chronology of WICC Implementation
City WICC report prepared WICC concept is born WICC master plan adopted Assessment hearing with 1,200 vocal citizens WICC program stopped City Council election Pro-WICC/Anti-WICC campaign Low voter turnout/Anti-WICC prevailed Deadlocked City Council State water management threatens potable allocation cutback Supportive rate study Supportive citizen's review committee Requested increase to potable water allocation denied WICC referendum 60% voter turnout WICC wins 2-to-1 Second assessment hearing Construction started for Phase I Phase 1 starts up Phase 2 start up is scheduled Phase 3 start up is scheduled

November 1985 January 1988 April 1988

November 9, 1988

November 1988 October 1989

November 1989 December 1989 February 1990 March 1992 September 1992 October 1994


to remind homeowners about dry season watering times and good conservation practices. The City also created an Irrigator Hotline for people to call to confirm watering schedules, and the City’s Code Enforcement began issuing citations to violators to make the message clear. As Cape Coral continues to grow, the City is looking to expand its secondary system at the same time that crews bring water and sewer service to new areas of this 114square-mile (295-km2) community. In another creative endeavor, the City is working to increase the supply of secondary water through weir improvements by seasonally raising weirs to store more water in the canals. These weir improvements may make it possible to supply secondary water to an even larger customer base. Cape Coral has one of the largest, fully integrated water management systems in the country and will bear watching in the future.


Convening a public advisory committee early in the project’s development, which included a broad cross section of community interests Engaging members of the advisory committee and others, including the Sierra Club, County Medical Society, and Chamber of Commerce, to speak on behalf of the project Developing easy-to-understand information materials and disseminating them widely to potential stakeholders Making presentations to community groups and held numerous workshops and open houses



„ Taking members of the public and key stakeholders


Learning Important Lessons When Projects Do Not Go as Planned

on tours of the pilot plant where taste tests were held using repurified water

Briefing policy-makers and their staffs

Over the last decade, reclaimed water proponents have been highly successful in convincing the public about the benefits of reclaimed water for irrigation. That “hurdle” has, for the most part, been surpassed. But public questions and concerns continue to emerge about using reclaimed water for anything related to potable supplies. Today, science and technology make it possible to treat reclaimed water to drinking water standards. But, even as an indirect water supply source, case studies continue to find hesitation by citizens to embrace highly treated reclaimed water as a potable water source. This is especially true when other water supply options become available. Over time, and as more successes in the potable reclaimed water arena are achieved, this hurdle may also be surpassed. The following 2 case studies illustrate some of the challenges that can emerge as programs strive to move forward from the conceptual stage. San Diego, California

While the project team worked to educate and involve stakeholders in the process from the early planning stages, the following “outside” factors emerged and may have influenced public perception:

Once the project moved from concept to design, the City of San Diego’s wastewater department took over as the lead agency. This may have served to portray the project as a wastewater disposal solution rather than a water supply solution. Lesson to consider: If possible, stay with the same project team, especially leadership, from inception through completion. Keep the project goal clear and unchanging. Try to avoid sending mixed messages. During the 5 years from concept to design, another water supply alternative emerged. Proponents of an agricultural water transfer positioned it as a superior alternative to indirect potable reuse and launched an aggressive promotional campaign. In fact, the 2 projects were complementary, one providing a new source of imported water, the other a locally controlled water source. Lesson to consider: If a new alternative is proposed in a public forum, it needs to be formally recognized and evaluated before the original or an enhanced concept can move forward. Otherwise, the credibility of the original concept may be harmed. In some instances, ideas can be blended through public involvement to develop a more tailored community solution. The goal is to partner with others wherever



In 1993, the City of San Diego began exploring the feasibility of using highly treated wastewater, or reclaimed water, to augment imported water supplies. The concept of this “Water Repurification Project” was to treat reclaimed water to an even higher standard and then pipe it into a surface water reservoir. There, the reclaimed water would blend with the raw water supply, thus increasing the water supply available. Some positive public involvement efforts undertaken by the Water Repurification Project team included:


possible and to avoid an “us versus them” environment.

Lesson to Consider: Developing ongoing relationships with knowledgeable reporters and editorial boards is critical.

The time when the project was ready for final approval from the San Diego City Council coincided with several competitive elections. The project became a political issue. Key votes were delayed until after the election. Lesson to consider: Much time is often dedicated to educating community leaders about a project. Elections can disrupt the timing of implementation because added time is then needed to educate new leaders. When possible, big picture planning should consider key election dates, timing project deadlines and approvals prior to any major shifts on a council or commission.

The National Research Council issued a report on indirect potable reuse just prior to the project’s consideration by the San Diego City Council. While the report was largely favorable, the executive summary included a statement that indirect potable reuse should be considered an “option of last resort.” That comment made national news and was viewed as scientific validation that the project was unsafe. Spurred by local media coverage and direct mail from political candidates criticizing the project, a group of County residents formed to actively oppose the project. The “Revolting Grandmas” attended all hearings and public meetings to speak against the project and wrote letters to the media and elected officials. Members of the Revolting Grandmas lived outside the City’s jurisdiction and, therefore, had not been included on project mailing lists to receive accurate information for the past 5 years. Lesson to Consider: While it may be impossible to identify every stakeholder group in the process, this situation highlights just how critical early identification of a complete list of stakeholders can be.



A State Assembly member running for re-election called for special state hearings on the project, providing a forum for the candidate’s allies to attack the project. The same candidate sent a direct-mail “survey” to constituents asking if they supported “drinking sewage.” An underdog City Council candidate raised the issue of environmental justice by stating, inaccurately, that while the wastewater source was the affluent part of the city, the water recipients were in lower economic and ethnically diverse neighborhoods. Even though this was not true, the misinformation spread with the help of local radio talk show personalities and African-American activists. Several African-American ministers appeared at City Council hearings to protest politicians “using them as guinea pigs.” Lesson to consider: If the public hears a particular “fact” as little as 3 times, then, regardless of whether or not the information is true, this “fact” will begin to be perceived as truth. This is why it is so important to correct inaccuracies whenever possible, as quickly as possible. If, for instance, a newspaper article provides incorrect facts about a project and no one calls the reporter to correct the story, then the report is filed in the newspaper archives as factual. The next time a story is needed about the project, a different reporter then uses the previous story for background information. This article is very likely to repeat the wrong information.


A private developer of gray water systems attacked the project repeatedly with elected officials and the media, claiming gray water was a superior water supply option. The company president argued gray water was safer and more cost-effective than indirect potable reuse. Lesson to Consider: Sometimes, providing a direct response to a party with an opposing view can be the correct response. But, at other times, providing a response may serve to validate the other person’s claims in the eyes of the public. It is important to evaluate the level of response needed on a caseby-case basis.

Public Outreach May not be Enough: Tampa, Florida

„ Even after briefings, the lead editorial writer for water

issues at The San Diego Union-Tribune felt any kind of water reuse was too costly and ill advised. News reporters borrowed the “Toilet to Tap” description (used by media covering a groundwater project in Los Angeles) in their ongoing coverage.

In the late 1990s, the City of Tampa, Tampa Bay Water, and the SWFWMD, in cooperation with the EPA, studied the feasibility of developing a water purification project for the area. Reclaimed water, treated further at a supplemental water reclamation treatment facility, would be blended with surface water and treated again at the City’s water treatment facility. A public outreach program was


developed to enhance and improve the public’s understanding of the region’s water problem, its long history of conflict over water issues, and public perceptions about government and indirect potable reuse. While there were significant challenges to overcome, a public information program began to make headway through the use of the following efforts:
„ Identified and interviewed key stakeholders, conducted


A National Research Council report critical of indirect potable reuse was released just prior to when the Tampa Bay Water Board was called upon to approve the project. The report created a perception that the scientific community was not in favor of indirect potable reuse.

focus groups, and conducted a public opinion survey
„ Developed project fact sheets, frequently asked ques-

The Tampa project shows the importance of gaining support of policymakers, senior staff and elected officials. It may be worthwhile to consider these among the first target audiences, before working toward a broader public involvement effort.

tions materials, and brochures
„ Drafted a comprehensive communication plan for the



Pinellas County, Florida Adds Reclaimed Water to Three R’s of Education

Formed a public working committee and developed its operating framework guide to the Independent Advisory Committee’s recommendations.

„ Developed a project video, website, and layperson’s

When Pinellas County Utilities renovated the South Cross Bayou Water Reclamation Facility, the department saw an opportunity to use the new facility as a learning laboratory to teach “real-life” science to students and other County residents. The effort to make the vision a reality began more than a year ago with the construction of an Educational/Welcome Center that is now home to a multifaceted, hands-on educational program. Initially focusing on high school science students and adult visitors, utility officials worked closely with County high school teachers to develop “Discover a Cleaner Tomorrow” as an appropriate curriculum to enhance classroom learning. The curriculum was designed to support National Science Standards, Sunshine State Standards, and student preparedness for the Florida Comprehensive Assessment Test (FCAT) tests. Through a partnership with the Pinellas County School Board, a certified science educator modifies the curriculum for each visiting class and teaches the scientific principles and methods involved in water reclamation. Before they visit the South Cross Bayou site, students are introduced to the topic of wastewater treatment through an animated video focusing on the role of bacteria. The video sets the tone for serious learning through humor in the light-hearted production. When they arrive at the site, students are introduced to the facility tour with a second short feature, a sequel to the classroom video. A third video was developed for the general public. Titled “Undissolved Mysteries,” it features a detective/narrator who roams through the facility uncovering the mysteries of water reclamation. After the video presentations, visitors board a tram that transports them through the 35-acre site. Hands-on investigation helps students and other visitors gain a better understanding of wastewater treatment processes.

„ Supported the Ecosystem Team Permitting process

that resulted in permit issuance
„ Conducted public meetings, open houses, and work-

shops Although the outreach program reached a broad audience and the project was permitted, it has yet to be implemented. Several factors contributed to the lack of implementation, including a lack of support among agency policymakers and senior staff. Specific examples include:
„ Policymakers viewed the project as a choice among

seawater desalination, creating a new reservoir in an old phosphate pit, and developing the purified water project. Many policymakers considered desalination the preferred option.

The City of Tampa Department of Sanitary Sewers was the main project proponent, positioning the project from the wastewater side. The City of Tampa Water Department was not actively involved. A general manager of a local water agency vocally opposed the project. Tampa Bay Water, the region’s water agency, did not speak out to counter the opposition.



Students test the wa