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HomeMy WebLinkAboutDPR A Path ForwardDIRECT POTABLE REUSE A Path Forward CALIFORNIA DIRECT POTABLE REUSE A PATH FORWARD George Tchobanoglous, Ph.D., P.E. Professor Emeritus Department of Civil and Environmental Engineering University of California, Davis Harold Leverenz, Ph.D., P.E. Research Associate Department of Civil and Environmental Engineering University of California, Davis Margaret H. Nellor, P.E. Principal Nellor Environmental Asso ciates, Inc., Austin, TX Texas Engineering Firm F ‐8738 James Crook, Ph.D., P.E. Environmental Engineering Consultant Boston, Massachusetts With Contributions by Takashi Asano, Ph.D., P.E. Jeff Mosher David Smith, Ph.D., P.E. Disclaimer This report was sponsored by the WateReuse Research Foundation and WateReuse California. The project sponsors and their Board Members assume no responsibi lity for the content of this publication or for the opinions or statements of facts expre ssed in the report. The mention of trade names of commercial products does not represent or imply the approval or endor sement of the WateReus e Research Foundation, WateReuse California, or their Boar d Members. This report is published solely for informational purposes. For more information, contact: WateReuse Research Foundation 1199 North Fairfax Street, Suite 410 Alexandria, VA 22314 703-548-0880 703-548-5085 (fax) www.WateReuse.org/Foundation © Copyright 2011 by the WateReuse Research Foundat ion and WateReuse California. All rights reserved. Printed in the United States of America Printed on Recycled Paper iii CONTENTS LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . vi LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . vii ACRONYMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . x CHAPTER 1: INTRODUCTION . . . . . . . . . . . . . . . . . . . . . 1 1-1 BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . 2 Amount of Water Recycled . . . . . . . . . . . . . . . . . . . 3 Barriers to Achieving Recycling Goal . . . . . . . . . . . . . . . . 3 1-2 RATIONALE FOR DIRECT POTABLE REUSE . . . . . . . . . . . . 3 1-3 SCOPE OF THIS REPORT . . . . . . . . . . . . . . . . . . . . 5 1-4 REPORT ORGANIZATION . . . . . . . . . . . . . . . . . . . . 6 CHAPTER 2: WORKSHOPS ON POTABLE REUSE . . . . . . . . . . . . . 8 2-1 RESEARCH NEEDS FOR THE POTABLE REUSE OF MUNICIPAL WASTEWATER, 1975 . . . . . . . . . . . . . . . . . . . . . 8 Purpose of Workshop . . . . . . . . . . . . . . . . . . . . . 9 Organization of Workshop . . . . . . . . . . . . . . . . . . . . 9 Workshop Findings . . . . . . . . . . . . . . . . . . . . . . . 9 Workshop Conclusion . . . . . . . . . . . . . . . . . . . . . . 10 2-2 PROTOCOL DEVELOPMENT: CRITERIA AND STANDARDS FOR POTABLE REUSE AND FEASIBLE ALTERNATIVES, 1980 . . . . . . . . . . . 11 Purpose of Workshop . . . . . . . . . . . . . . . . . . . . . 11 Organization of Workshop . . . . . . . . . . . . . . . . . . . . 11 Workshop Findings . . . . . . . . . . . . . . . . . . . . . . . 11 Workshop Recommendations . . . . . . . . . . . . . . . . . . 13 2-3 DIRECT POTABLE REUSE WORKSHOP, 2010 . . . . . . . . . . . . 14 Purpose of Workshop . . . . . . . . . . . . . . . . . . . . . . 14 Organization of Workshop . . . . . . . . . . . . . . . . . . . . 14 Workshop Findings . . . . . . . . . . . . . . . . . . . . . . . 14 Workshop Recommendations . . . . . . . . . . . . . . . . . . 15 2-4 REVIEW OF WORKSHOPS’ FINDINGS AND CONCLUSIONS . . . . . 15 CHAPTER 3: REVIEW OF DIRECT POTABLE REUSE PROJECTS . . . . . . 17 3-1 CITY OF WINDHOEK, NAMIBIA . . . . . . . . . . . . . . . . . 18 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 18 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . 19 3-2 PURE CYCLE CORPORATION . . . . . . . . . . . . . . . . . 19 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 20 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . 22 3-3 DENVER POTABLE REUSE DEMONSTRATION STUDY . . . . . . . . 22 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 22 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . 23 iv 3-4 INTERNATIONAL SPACE STATION . . . . . . . . . . . . . . . . 24 Treatment Process Flow Diagrams . . . . . . . . . . . . . . . . . 24 Water Recovery System . . . . . . . . . . . . . . . . . . . . . 24 Urine Processor Assembly . . . . . . . . . . . . . . . . . . . . 25 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . 26 3-5 VILLAGE OF CLOUDCROFT, NEW MEXICO . . . . . . . . . . . . 26 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 27 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . 28 3-6 BIG SPRINGS, TX . . . . . . . . . . . . . . . . . . . . . . . 28 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 29 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . 30 3-7 ORANGE COUNTY WATER DISTRICT . . . . . . . . . . . . . . . 30 Treatment Process Flow Diagram . . . . . . . . . . . . . . . . . 31 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . 31 3-8 REVIEW OF DIRECT POTABLE REUSE SYSTEMS . . . . . . . . . 31 CHAPTER 4: TECHNICAL ISSUES IN DIRECT POTABLE REUSE . . . . . . 34 4-1 INTRODUCTION TO DPR SYSTEMS . . . . . . . . . . . . . . . 35 Advanced Wastewater Treatment Processes . . . . . . . . . . . . . 35 Balancing Water Chemistry . . . . . . . . . . . . . . . . . . . 37 Engineered Storage Buffer for Flow Retention and Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . 38 Blending with Other Water Supply Sources . . . . . . . . . . . . . 38 Multiple Barriers . . . . . . . . . . . . . . . . . . . . . . . . 39 4-2 ENGINEERED STORAGE BUFFERS FOR FLOW RETENTION AND QUALITY ASSURANCE . . . . . . . . . . . . . . . . . . . . . . . . 40 Environmental Buffer . . . . . . . . . . . . . . . . . . . . . . 41 Engineered Storage Buffer . . . . . . . . . . . . . . . . . . . . 43 4-3 MEASURES TO ENHANCE RELIABILITY . . . . . . . . . . . . . . 45 Source Control . . . . . . . . . . . . . . . . . . . . . . . . 46 Enhanced Fine Screening . . . . . . . . . . . . . . . . . . . . 46 Elimination of Untreated Return Flows . . . . . . . . . . . . . . . 47 Flow Equalization . . . . . . . . . . . . . . . . . . . . . . . 47 Operational Mode for Biological Treatment . . . . . . . . . . . . . 48 Improved Performance Monitoring . . . . . . . . . . . . . . . . . 49 Ongoing Pilot Testing . . . . . . . . . . . . . . . . . . . . . . 50 4-4 MONITORING AND CONSTITUENT DETECTION . . . . . . . . . . 50 Types of Monitoring . . . . . . . . . . . . . . . . . . . . . . 51 Monitoring Strategies . . . . . . . . . . . . . . . . . . . . . . 51 Monitoring Locations . . . . . . . . . . . . . . . . . . . . . . 52 Monitoring at the Engineered Buffer . . . . . . . . . . . . . . . . 52 4-5 FUTURE DEVELOPMENTS IN DPR . . . . . . . . . . . . . . . 52 New Wastewater Treatment Processes . . . . . . . . . . . . . . 54 Blending with Natural Waters . . . . . . . . . . . . . . . . . . . 54 New Advanced Treatment Technology . . . . . . . . . . . . . . . 54 Redundant Reverse Osmosis . . . . . . . . . . . . . . . . . . 54 4-6 SUMMARY OF ISSUES FOR IMPLEMENTATION OF DPR . . . . . . . 54 v CHAPTER 5: PUBLIC ACCEPTANCE ISSUES IN DIRECT POTABLE REUSE . . . . . . . . . . . . . . . . . . . . . . 58 5-1 PUBLIC PERCEPTION OF DPR PROJECTS . . . . . . . . . . . . 58 5-2 CHALLENGES FOR DIRECT POTABLE REUSE . . . . . . . . . . . 59 5-3 IMPLEMENTATION STRATEGIES FOR DIRECT REUSE . . . . . . . 60 CHAPTER 6: RESEARCH NEEDS IN DIRECT POTABLE REUSE . . . . . . . 62 6-1 RESEARCH TOPIC: SIZING OF ENGINEERED STORAGE BUFFER . . . . . . . . . . . . . . . . . . . . . . 62 6-2 RESEARCH TOPIC: TREATMENT TRAIN RELIABILITY . . . . . . . . 64 6-3 RESEARCH TOPIC: BLENDING REQUIREMENTS . . . . . . . . . . 65 6-4 RESEARCH TOPIC: ENHANCED MONITORING TECHNIQUES AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . 66 6-5 RESEARCH TOPIC: EQUIVALENT ADVANCED TREATMENT TRAINS . . . . . . . . . . . . . . . . . . . . . 67 6-6 RESEARCH TOPIC: COMMUNICATION RESOURCES FOR DPR . . . . 68 6-7 RESEARCH TOPIC: ACCEPTANCE OF DIRECT POTABLE REUSE . . . . . . . . . . . . . . . . . . . . . . . 70 6-8 RESEARCH TOPIC: ACCEPTANCE OF POTABLE RE USE . . . . . . . 71 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . 73 APPENDIXES A TEXT: SENATE BILL 918 . . . . . . . . . . . . . . . . . . . . 77 B LETTER TO BIG SPRINGS, TEXAS FROM TEXAS COMMISSION ON ENVIRONMENTAL QUALITY . . . . . . . . 85 vi FIGURES 3-1 Water Reclamation Process Flow Diagrams at the Goreangab Water Reclamation Plant in Windhoek, Namibia . . . . . . . . . . . . . . 19 3-2 Pictorial view of Pure Cycle Corporat ion closed water-recycling system process flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . 21 3-3 Schematic view of Pure Cycle Corporation closed water-recycling system process flow diagram . . . . . . . . . . . . . . . . . . . . . . 21 3-4 Treatment process flow diagram for the Denver, CO potable water reuse demonstration project . . . . . . . . . . . . . . . . . . . . . . 23 3-5 Treatment process flow diagram for the treatment of condensate from the temperature and humidity control system and distillate from the urine recover system on the International Space Station . . . . . . . . . . . . . 25 3-6 Treatment process flow diagram for the treatment of urine on the International Space Station . . . . . . . . . . . . . . . . . . . 26 3-7 Schematic of Cloudcroft, NM DPR treatment process flow diagram . . . . 27 3-8 Schematic of Big Springs, TX treatment process flow diagram . . . . . 29 3-9 Schematic flow diagram for 2.65 x 10 4 m 3 /d (70 Mgal/d) advanced water treatment facility at the Orange County Water District, Fountain Valley, CA . . . . . . . . . . . . . . . . . . . . . . 32 4-1 Summary of opportunities for indirect and direct potable reuse . . . . . 36 4-2 Potable reuse treatment scenarios . . . . . . . . . . . . . . . . 37 4-3 Illustration of management, operational, and technological barriers in direct potable reuse . . . . . . . . . . . . . . . . . . . . . . . . . 40 4-4 Proven and conceptual engineered buffer systems. . . . . . . . . . . . . . . 44 4-5 Typical wastewater-treatment plant flow diagram incorporating flow equalization . . . . . . . . . . . . . . . . . . . . . . . 48 4-6 Representative sampling locations DPR treatment process flow diagram . . 52 4-7 Potential potable reuse treatment scenarios . . . . . . . . . . . . . 55 vii TABLES 4-1 Summary of monitoring locations in DPR systems . . . . . . . . . . . 53 4-2 Technical issues in the implementation of direct potable reuse . . . . . . 56 5-1 Public acceptance issues in the implementation of direct potable reuse . . . . . . . . . . . . . . . . . . . . . . . . . 61   viii ACRONYMS ac-ft/yr Acre-feet per year ft Feet AWT Advanced water treatment CDPH California Department of Public Health CEC Constituents of emerging concern CRMWD Colorado River Municipal Water District DPR Direct potable reuse ECLSS Environmental control and life support systems gal/d Gallons per day GWRS Groundwater Replenishment System HACCP Hazard analysis and critical control points IPR Indirect potable reuse ISS International Space Station kWh Kilowatt-hour MCL Maximum contaminant levels Mgal/d Million gallons per day mo Month NASA National Aeronautics and Space Administration NDMA N-nitrosodimethylamine NWRI National Water Research Institute OCWD Orange County Water District OCSD Orange County Sanitation District RFP Request for proposals QRRA Quantitative relative risk assessment RWC Recycled water contribution SWRCB State Water Resources Control Board TECQ Texas Commission for Environmental Quality TDS Total dissolved solids TOC Total organic carbon UPA Urine processor assembly U.S. United States U.S. EPA U.S. Environmental Protection Agency WHO World Health Organization UVA Ultraviolet absorbance WRRF WateReuse Research Foundation WRS Water recovery system yr year ix PREFACE Terms used throughout this report are summ arized in the following table for ease of reference. Term Definition a Advanced treatment Removal of residual trace constituents following treatment by micro- and ultrafiltration, with or without deminer alization, as required for specific water reuse applications. Barrier A measure used to limit the presence of specific constituents, such as pathogens. Barriers could include cons umer education, source control, wastewater treatment pr ocesses, dilution and natural attenuation in the water body, storage in reservoirs, effective drinking water treatment, and extensive raw and treated water monitoring to ensure high quality drinking water. De facto indirect potable reuse The withdrawal of drinking water from rivers or surface water reservoirs that contain varying amount of treated wastewater discharged from upstream cities, industries, and agricultural areas. Direct potable reuse The introduction of purified water from an engineered storage buffer either directly into a potable water supply distribution system downstream of a water treatment plant, or into the raw water supply immediately upstream of a water treatment plant. In direct potable reuse, purified water is not placed into an environmental buffer. Engineered storage buffer Water storage containm ent facility of sufficient volu metric capacity to retain purified water for a sufficient period of time to allow for the measurement and reporting of specific constituents to be assured that the quality of water provided meets all applicable public health standards prior to discharge to the potable water system. Environmental buffer A groundwater aquifer or surface water storage reservoir into which purified water is placed and where it must remain for a specified period of time, before bring withdrawn for potable purposes. Indirect potable reuse The planned incorporation of purified water into an environmental buffer for a specified period of time before br ing withdrawn for potable purposes. Multiple barriers An engineered system in which a number of independent barriers are combined in series to achieve a high degree of reliability. Product water Water discharged from a specified treatment train. Purified water Advanced treated water whose quality has been deemed safe for human consumption, regardless of the source of the water. Recycled water contribution (RWC) The volume of recycled water divided by the total volume of water (recycled plus dilution water from other sources). Secondary treatment Removal of biodegradable organic matter (in solution or suspension) and suspended solids, with or without nutrient removal. Disinfection is also typically included in the definition of conventional secondary treatment. Tertiary treatment Removal of residual suspended and colloidal solids (after secondary treatment), usually by granular medium filtration, microscreens, cloth filters, or membranes (e.g., micro- and ultrafiltration). a The definitions presented in this table are co nsistent with, but not direct statements from, Senate Bill 918 and/or California Department of Public Health (CDPH) draft groundwater recharge regulations.  x   ACKNOWLEDGMENTS Dr. Takashi Asano reviewed several dr afts of the report and provided constructive criticisms and suggestions. Mr. Jeff Mosher reviewed the report and provided comments. Dr. Davi d Smith, prepared a firs t draft of Chapter 1 and reviewed and commented on several drafts of the report. Mr. Tom Richardson reviewed the draft and provided constr uctive comments and suggestions. Dr. Harvey Collins and Dr. Rhodes Trussell graci ously made time available from their busy schedules to discuss DPR with the authors. 1 1 INTRODUCTION Due to increasing water scarcity, the limits of current conventional water supplies, and the need for water agencies to maximize beneficial use of all available water resources, water agencie s and others are interested in defining the guidelines and criteria needed for direct potable reuse (DPR) in which purified water is introduced directly in to a potable water supply distribution system or into the raw water supply imm ediately upstream of a water treatment plant. Reflecting the increased interest in DPR, the Governor of the State of California signed into law Senate Bill 918 in September 2010. This bill mandates that the California Depart ment of Public Health (CDPH) adopt uniform water recycling criteria for indirect potable reuse (IPR) for groundwater recharge by the end of 2013. If an expert panel convened pursuant to the bill finds that the criteria for surface water augmentation would adequately protect public health, the development of criteria for surface wate r augmentation by the end of 2016 is also mandated in the bill. Further, the bill requires CDPH to in vestigate the feasibility of developing regulatory crit eria for DPR and to provide a final report on that investigation to the Legislature by the end of 2016. The full text of Senate Bill 918 may be found in Appendix A. The Ca lifornia Water Code (SWRCB, 2011) has been amended to include the provis ions of Senate Bill 918. In light of the interest in DPR, the purpos e of this report is to provide a general overview current knowledge related to DPR and to identify the information that must develop through targeted studies to inform the public, public and private water agencies, and regulatory agencies regar ding the feasibility of implementing DPR as a viable water supply management option. Although the background information on DPR and the needed research identified in this report are applicable across the country and throughout the world, the primary focus is on providing information so that the feasibility of DPR can be evaluated in California. 2 1-1 BACKGROUND Primary uses of recycled water in California are for irrigation of agricultural crops, landscape irrigation, and groundwater re charge. Although irri gation with treated wastewater has been occurring for decades, it is reaching logistical and economic constraints. The augmentation of drinking water sources with purified water through groundwater recharge or surface water additions is known as indirect potable reuse (IPR). Groundwater rechar ge is becoming of greater interest in areas needing to augment or diversify their water supply. Compliance with CDPH draft regulations (CDPH, 2008) for groundwater recharge requires (1) a minimum residence time in an aquifer, called an environmental buffer; and (2) tertiary or advanced wastewater treat ment depending on the type of recharge application (surface spreading versus inject ion) in combination with the allowable recycled water contribution (RWC) and other sources of recharge water not of wastewater origin, which serve to dilute the recycled water. The draft recharge regulations do not specify the water sour ce used for dilution, but would allow dilution with groundwater. Compliance with drinking water and other water quality standards is determined in the product water, with the exception of disinfection byproducts for surface spreading projects , where compliance is determined after passage through the vadose zone. The CDPH is also in the process of devel oping draft regulations for surface water augmentation that are likely to include similar types of requirements regarding retention time, treatment, and blending with the surface water. The primary benefit of an environmental buffer is to prov ide time to react should treatment be inadequate due to process failure or other fa ctors. In the past, it was thought that the extended residence time afforded by the environmental buffer would also provide for additional treatm ent. While an environmental buffer is relevant for tertiary treated water, any water quality benefits afforded by the retention of water that has been purified with reverse osmo sis and advanced oxidation, or other types of advanced treatment, in an envir onmental buffer are minor, if any. 3 Amount of Water Recycled In 2009, the California State Water Re sources Control Board (SWRCB) approved a Recycled Water Policy which includes a goal to increase the use of recycled water over 2002 levels by at least 1 million ac-ft/yr (acre-feet per year) by 2020 and by at least 2 million ac-ft/yr by 2030 (SWRCB, 2009). As of 2010, actual recycling is estimated to be 650,000 ac-ft (Br yck et al., 2008). While this volume of water represents a major ac hievement, it falls far short of the State’s goal, and only represents only about 19% of the approximately 3.5 million ac-ft of treated wastewater discharged to the ocean each year. Barriers to Achieving Recycling Goal A number of barriers make it difficult to achieve the State’s water recycling goal, including: • Expansion of agricultural i rrigation, in general, is not feasible due to the long distance between the large sources of recycled water (cities) and the major agricultural demand (rural areas). • Cost and disruption to construct pi pe systems to convey recycled water and the need to provide winter water storage facilities furt her limit agricultural reuse. • Landscape irrigation may not be economic ally feasible due to the dispersed nature of the demand. • The cost of providing parallel distribut ion of tertiary treated supply is high due to the fact that the dist ance between large users in most communities is large and most water is consumed by small user s that are not served efficiently and seasonality issues. • Historically, the value of water fr om surface and groundwa ter supply sources has not reflected the true costs of provid ing the supply, result ing in a distinct economic disadvantage for the production of purified water. 1-2 RATIONALE FOR DIRECT POTABLE REUSE In the future, a decision to implement DP R, which would occur on a case-by-case basis, will be based on a combination of environmental and economic factors. 4 Communities deciding to implement DPR would be influenced by the same factors that have driven some communi ties to implement IPR plus some additional factors. The typical factors driving communities to IPR include the following: • The need for construction and operat ion of a parallel recycled water distribution system required to supply tert iary water to irrigation sites is avoided. Regardless of cost, insta llation of parallel distribution systems may not be feasible in some urban environments due to space and disruption constraints. • Alternative sources of water are ei ther of poor quality or prohibitively expensive. • Traditional sources of surface wate r supply are being reduced because of diversions to meet environmental pr otection regulations, reductions in allocations, and reductions in flow brought about by climate change. • Groundwater has been overdrafted and only poor quality groundwater is now available in some areas. • With advanced treatment technology it is now possible to remove contaminants effectively and reliably to extremely low levels that have no known health concerns. • Recycled water is a reliable source of supply which exists in close proximity to the demand. Additional factors that would drive some communities to DPR include the following: • Communities that lack suitable hydrogeology for groundwater recharge cannot implement IPR projects based on the current CDPH draft regulations. While no regulations hav e been established for surface water augmentation, when draft ed they are likely to include blending and residence time requirements that may lim it this type of reuse application to large reservoirs (which are not available to many communities). • Direct potable reuse is potentially le ss costly than the use of tertiary recycled water for irrigation. The typica l cost for parallel distribution of 5 tertiary treated supply is $400 - $2100/ac -ft whereas the typical cost for advanced membrane treatment includi ng advanced oxidation is $700 - $1,200/ac-ft (Atwater, 2008; Lich ty, 2008; and Richardson, 2011). • Direct potable reuse, in which purified water is introduced into the water supply without the need for an extended residence time in an environmental buffer, may represent a feasible alternative approach for some communities to augment and diversify their water supply portfolio. • Direct potable reuse may require le ss energy than is required for other water supply sources. For example, t he energy required to provide 1 ac-ft to an Orange County water system (Deshmukh, 2010; Taffler et al., 2008) is: o Ocean desalination = 3,700 kWh (kilowatt-hour) o State Project water = 3,500 kWh o Colorado River water = 2,500 kWh o Purified water = 800 - 1,500 kWh • Direct potable reuse avoids potential water quality issues associated with groundwater and surface water sources (e.g., contamination plumes or illicit surface water discharges). • Current technology is sufficient to replace the environmental buffer with an engineered storage buffer through a comb ination of monitoring, storage, and treatment reliability measures. Fu ture monitoring technology may obviate the need for an engi neered storage buffer. 1-3 SCOPE OF THIS REPORT The scope of this report is to identif y information and the types of research studies that are necessary to provide a starting rationale for the discussion of the feasibility of DPR, incl uding; engineering, economic , regulatory, and public acceptance considerations. The focus of the recommended research studies is on the following two potential barriers to DPR implementation: 6 • Science and Engineering. Studies needed to identify information on the methods and means of implementi ng DPR with and wi thout an engineered storage buffer as a substitute for t he environmental buffer now required. • Public Acceptance. Studies and activi ties needed to gain a sufficient level acceptance of DPR by the public such that it is not a barrier to implementation are described. Specifically, the results of the studies described in this report are intended to provide information and background material for consideration by the CDPH expert panel that will be convened purs uant to Senate Bill 918 to provide recommendations to CDPH regarding the f easibility of developing uniform water recycling criteria for DPR. Nothing in th is report should be regarded as an implicit or explicit statement t hat the outcome of the DP R feasibility discussion is foregone in favor of, or against DPR. 1-4 REPORT ORGANIZATION This report is organized into the following six chapters: 1. Introduction 2. Workshops on Potable Reuse 3. Review of Direct Potable Reuse Projects 4. Technical Issues in Direct Potable Reuse 5. Public Acceptance Issues in Direct Potable Reuse 6. Research Needs in Direct Potable Reuse A review of the important workshops on potable reuse, held over the past 35 years, is presented in Chapter 2. The purpose, organization, findings, and recommendations or conclusions are presen ted for each workshop. DPR projects that have been implemented in the past and/or are currently in operation or planned are reviewed in Chapter 3. The revi ew of these DPR projects is intended to provide perspective on the different process configurati ons that have been used to achieve DPR. Based on the mate rial presented in Chapters 2 and 3, the technical issues that must be addressed if DPR is to become a viable option are identified and discussed in Chapter 4. P ublic acceptance issues that must be 7 addressed if DPR is to be a viable option are presented and discussed in Chapter 5. From the delin eation of the issues in Chapters 4 and 5, research projects designed to resolve the issues associated with DPR are presented in Chapter 6. References cited in the report are presented fo llowing Chapter 6. 8 2 WORKSHOPS ON POTABLE REUSE The purpose of this chapter is to review past and current thinking with respect to issues on potable reuse. The literature c ontains thousands of articles, reports, presentations, and analyses that deal with some aspect of DPR. From this vast amount of available material, three reports stand out as being seminal with respect to DPR. They are: 1. Research Needs for the Potable R euse of Municipal Wastewater (U.S. EPA, 1975) 2. Protocol Development: Criteria and Standards for Potable Reuse and Feasible Alternatives (U.S. EPA, 1980) 3. Direct Potable Reuse Workshop (CUWA et al., 2010) Each of these reports reflects the best thinking at the time from academics, consultants, practitioners, the public, and regulators. Not surprisingly, many of the issues identified in t he 1975 workshop are still timely. In what follows, each of these reports is reviewed with respect to (1) the purpose of the workshop; (2) the organization of the workshop; (3) workshop findings; and (4) workshop conclusions or summary or recommendat ions, depending on the format used. In most cases, material from the wor kshop summaries has been quoted directly rather than paraphrasing, so that the flavor of the report is not lost. 2-1 RESEARCH NEEDS FOR THE POTABLE REUSE OF MUNICIPAL WASTEWATER, 1975 Just three years after the passage of the Clean Water Act and the formation of the U.S. Environmental Protection A gency (U.S. EPA), a workshop was held in Boulder, CO, on March 17-20, 1975, on Research Needs for the Potable Reuse of Municipal Wastewater (U.S. EPA, 1975). 9 Purpose of Workshop The stated objective of the workshop was to : “define and establish the priorities for research needed to develop confidence in the reuse of wastewater for potable purposes” (U.S. EPA, 1975). Organization of Workshop “The first day of the workshop was devot ed to the presentation and discussion of current research and demonstration activities related to treatment technology and health effects associated with current and proposed water reuse applications.” The second and third days of the workshop were devoted to small group discussions. The discussion groups were as follows: 1. Treatment reliability and effluent quality control for potable reuse, 2. Wastewater treatment for potable reuse, 3. Health effects of potable reuse associated with inorga nic pollutants, 4. Health effects of potable reus e associated with viruses and other biological pollutants, 5. Health effects of potable reuse associated with organi c pollutants, and 6. Socio-economic aspects of potable reuse” (U.S. EPA, 1975). Workshop Findings The principal findings from the sma ll group discussions were as follows. 1. Treatment reliability and effluent quality control for potable reuse . The following research areas were iden tified: (1) establish water quality standards for potable reuse, (2) define r equirements for fail/safe reliability, and (3) define allowable limits of product quality variability. 2. Wastewater treatment for potable reuse . A large-scale demonstration effort to “characterize the long-term e ffectiveness and reliability of various alternative treatment systems for producing a potable q uality product” (U.S. EPA, 1975) was identified as the principal need. 3. Health effects of potable reuse a ssociated with inorganic pollutants . This group identified the balanced use of epidemiological and toxicological methods as being extremely importan t. An epidemiological program was recommended that included an “. . . a ssessment of the relationship 10 between current water qual ity and the incidence and prevalence of chronic diseases, as well as a determination of the body burdens of inorganic substances. Recommended toxicological studies included in vitro screening of concentra ted toxicants, in vivo animal toxicity testing, and population dose estimation.” (U.S. EPA, 1975) 4. Health effects of potable reuse associated with viruses and other biological pollutants. This group “. . . highlighted the development and evaluation of rapid and relatively simp le methods for detection of viruses having major public health significance as being among the areas warranting extensive research.” (U.S . EPA, 1975) Another high priority research recommendation was “Determining the degree and mechanisms of removal and inactivation of viruses in reclaimed waters .” (U.S. EPA, 1975) 5. Health effects of potable reuse associated with organic pollutants . The principal recommendation from this group was “. . . that EPA should develop a viable and visible program to assess the potability of reused water.” (U.S. EPA, 1975) 6. Socio-economic aspects of potable reuse . The two principal recommendations from this group were to : (1) “. . . identify the extent to which the U.S. population is presently being supplied former wastewater as a part of the raw water supply and (2) that a public education program be undertaken to indicate the true pict ure concerning the current practice of indirect water re cycling.” (U.S. EPA, 1975) Workshop Conclusion The conclusion from the workshop was that it was “. . . appar ent that there are many specific research needs related to treatment technology and reliability, health effects, and socio-economic considerations for potable water reuse. The importance of proceeding with the accomplishm ent of this research is related not only to the recognized need fo r future direct reuse, but also because of the insight these investigations will provide concerning our current supply sources, 11 many of which are currently influenced by upstream discharges of municipal and industrial wastewaters.” (U.S. EPA, 1975) 2-2 PROTOCOL DEVELOPMENT: CRITERIA AND STANDARDS FOR POTABLE REUSE AND FEASIBLE ALTERNATIVES, 1980 In 1980, the U.S. EPA sponsored a workshop on Protocol Development: Criteria and Standards for Potable Reuse and Feasible Alternatives . The workshop was held at Airlie House in Warrenton, VA on July 29-31, 1980 (U.S. EPA, 1980). Purpose of Workshop “The purpose of this workshop was not to develop specific criteria and standards but to provide guidance with respect to approaches, problems, solutions and needed research or investigations for establishing a pathway to protocol development for potable reuse criteria and standards and for consideration of non -potable options” (U.S. EPA, 1980). Organization of Workshop The workshop was organized into two major sections. The firs t section included introductory papers that outlined the broad issues. The second section included six work groups that presented their reports and revi sed issue papers with conclusions and recommendations regarding protocol development for potable reuse criteria and standards, and non-potable options (U.S. EPA, 1980). The six groups were: 1. Chemistry, 2. Toxicology, 3. Microbiology, 4. Engineering, 5. Ground-Water Recharge, and 6. Non-Potable Options. Workshop Findings The principal findings from the sma ll group discussions were as follows. 1. Chemistry . "Specific analytical methods exist for 114 specific organic priority pollutants and for other designated organic contaminants in 12 drinking water. Analytical quality control has been established for these contaminant analyses and is being tested. However, many more specific organic contaminants remain without systematic methodology or quality control procedures. Broad spectrum analysis to determine the presence of many organic chemicals si multaneously is needed on a routine basis to help define the presence and variability of these components." (U.S. EPA, 1980) 2. Toxicology. "Prevention of excessive exposure to inorganic, radiologic and particulate substances can generally be handled by setting maximum contaminant levels (MCLs) and by app lication of appropriate treatment technology. However the management of risks from organic substances presents more complex problems. Where adequate information is available on specific organics of concern, additional MCLs should be set. With respect to the non-MCL and unknown organic fractions an innovative approach was recommended." (U.S. EPA, 1980) 3. Microbiology. "Proposals for direct potable reuse require a complete reevaluation of the means fo r biological control. There should be no detectable pathogenic agents in potable reuse water. Potable reuse requires stricter microbiological standards, including quality control monitoring than the current national coliform MCLs for drinking water." (U.S. EPA, 1980) 4. Engineering. "In considering the various available treatment systems and approaches, it was felt that treatment technology does not appear to be a limiting factor and that maximum-flexibility should be allowed in treatment designs so that the most cost effective approaches can be implemented which will meet health requirement s, including fail-safe operation. However, because present national drinking water standards are not intended for direct potable reuse wa ters, comprehensive standards and criteria should include specific require ments for direct reuse applications." (U.S. EPA, 1980) 13 5. Ground-Water Recharge. “Important benefits can be obtained by ground- water recharge. In addition to providing an economical means of storage with reduced evapotranspiration, subsurface passage removes some contaminants and retards the movement of others by means of filtration, biodegradation, volatilization, sorption, chemical precipitation, and ion exchange. Its use as part of a syste m to produce potable reuse water is encouraged." (U.S. EPA, 1980) 6. Non-Potable Options . "In the United States t here are now more than 500 successful wastewater reuse projects utilizing non-potable options: such options are the preferred method of r euse and should be considered in the decision-making proce ss before the potable reuse option. However, a variety of steps need to be taken before non-potable options can be given maximum utilization." (U.S. EPA, 1980) Workshop Recommendations The principal recommendations resulting from this workshop were as follows: 1. "Development of comprehensive standar ds and criteria to define potable water regardless of source. 2. Undertaking a detailed characteriza tion of potential sources of reclaimed water covering variability, frequen cy and concentration ranges for the various contaminants. 3. Undertaking a major e ffort to examine unknown or inadequately known organic chemical components. 4. Conduct of toxicological concentrate studies as a key element in a decision-making protocol in volving many factors. 5. More stringent microbi ology requirements. 6. Serious consideration of ground-wate r recharge options for potable reuse. 7. Serious consideration of non-potable reuse options for extending available public water supply." (U.S. EPA, 1980) 14 2-3 DIRECT POTABLE REUSE WORKSHOP, 2010 In 2010, WateReuse California held the Direct Potable Reuse Workshop with the California Urban Water Agencies and Natio nal Water Research Institute (NWRI), as cosponsors . The workshop was held in Sacramento, CA on April 26-27, 2010 (CUWA et al., 2010). Purpose of Workshop The objective of the Direct Potable Reuse Workshop was to identify information gaps that need to be addressed so that di rect potable reuse regulations can be developed as appropriate. Organization of Workshop The workshop was organized into parts involving presentations of prepared introductory white papers and breakout group deliberations. Two white papers were sponsored in advance of the wor kshop. NWRI sponsored the development of Regulatory Aspects of Direct Potable Reuse in California (Crook, 2010) and WateReuse California spons ored the development of Public and Political Acceptance of Direct Potable Reuse (Nellor and Millan, 2010). In addition, research topics developed at the Wa teReuse Research Foundation (WRRF) Research Needs Workshop (WRRF, 2009) were summarized. A discussion period followed each presentation. In the second part of the workshop, parti cipants were separated into four groups, based on areas of expertise, to deliberate on the following four focus areas: 1. Treatment, 2. Monitoring, 3. Regulatory, and 4. Public Acceptance. Workshop Findings Information gaps in the following subject areas were addressed at the workshop in the context of the four focus areas identified above: • Public acceptance. • Communication between water supply chain agencies, and the 15 public/customers. • Microbial and chemical constituents of concern. • Effectiveness and reliability of treatment unit processes. • Multiple barriers of protection. • Monitoring needs (treatment processes and product water). • Use of indicators/surrogates for both microbial and chemical constituents. • Redundancy in treatment. • Management and operational controls. • Permitting issues. Workshop Recommendations The results of the workshop were summa rized in a report (CUWA et al., 2010). The principal outcome of the works hop was the identified need to develop a workplan based on the workshop recomme ndations, including research topics (an important element of this report), funding sour ces, and appropriate timing, which is the subject of this report. 2-4 REVIEW OF WORKSHOPS’ FINDINGS AND CONCLUSIONS In assessing the findings of the three wo rkshops, the similarities are striking. Many, if not all, of the issues identif ied in the 1975 workshop were still being debated and discussed in the 1980 wor kshop and are still being debated and discussed in the 2010 workshop. The most significant technological changes between the 1975 and 1980 workshops and t he 2010 workshop are in the areas of biological and chemical analysis and engineering technology. The rapid development of analytical capabilities in the areas of microbiology, toxicology, and chemical analysis, with specific em phasis on trace organic constituents is well beyond what was imagined in the early workshops. The technological changes have similarly been remarkable, es pecially in the areas of membrane technology and advanced oxidation. With the treatment technologies now available, as discussed in Chapters 3 and 4, it is possible to remove chemical and microbial constituents of concern to very 16 low and what are believed to be insignificant levels with regard to human health. With ongoing technological developments, even more robust treatment process performance will be achieved. What remain s to be technologically resolved to obtain regulatory approval for DPR is related to: (1) the need for and size of engineered buffers, (2) system reliabi lity, and (3) appropriate monitoring techniques; these subjects are examined in Chapter 4. In each of the three workshops, public acceptance was identified as a barrier to DPR; this issue is further examined in Chapter 5. The needed research for both technological and public acceptance issues is proposed in Chapter 6. At the April 2010 workshop, a number of legal and regulatory challenges were identified regarding re gulatory authority fo r DPR under California’s current laws and regulations. For example, until water recycling requirements are established for DPR, DPR is prohibited under Califor nia Water Code section 13524. In addition, further clarification is needed to define the point at which recycled water transitions from legal author ity under state and federal wa stewater laws to water laws. This situation is particularly co mplex because recycled water is treated as a waste for purposes of permitting under va rious sections of the California Water Code. The manner in which recycled water is “discharged” will also have an impact on applicable water quality requirement s. For example, if the recycled water is directly introduced into a wate r treatment plant or distribution system, only drinking water laws and regulations would apply, albeit with potentially added scrutiny as part of a water supply’s source water assessment. If recycled water is introduced into a reservoir imm ediately upstream of a water treatment plant’s intake, then both wastewater and drinking water laws would apply, and in some cases the applicable wastewater qua lity standards might be more stringent than drinking water requirements. It is expected that these kinds of issues will be explored as part of the Senate Bill 918 panel deliberations regarding DPR feasibility. 17 3 REVIEW OF DIRECT POTABLE REUSE PROJECTS An overview of projects that are exam ples of DPR, witho ut an environmental buffer, is presented in this chapter. The projects described include examples that (1) have been undertaken in the past, (2) are currently in operat ion, or (3) are under design/construction. The importance of these examples is that the treatment process flow diagrams and tr eatment technologies employed have been accepted by various regulatory authorities as being able to produce safe potable drinking water, and that the impl ementation of these projects has been accepted by the public. Although not an ex ample of DPR, the Orange County Water District (OCWD) Groundwater Replenishment System (GWRS) is also included because the purified water that is produced for groundwater recharge represents an example where the water is safe for direct potable reuse and can serve as a benchmark for other suitable technologies (Burris, 2010). The seven selected projects to be reviewed are: 1. City of Windhoek, Namibia, 2. Pure Cycle Corporation, Colorado, 3. Denver Potable Reuse Demonstration Project, 4. National Aeronautics and Space Admi nistration (NASA) International Space Station, 5. Village of Cloudcroft, New Mexico, 6. Big Springs, Texas, and 7. Orange County Water District GWRS, California. The treatment process flow diagrams and the specific technologies used will serve as a basis for the development of alternative treatment strategies in Chapter 4, which, in turn, will serve as the basis for identifying unresolved questions concerning DPR. 18 The focus of the following review is prim arily on treatment technologies and not specific constituents, micr obial properties, toxicological properties, or public acceptance. Based on the reported studies, it is clear that with existing proven technologies, the production of safe potable drinking water is achievable. What needs to be researched are the methods and facilities that are necessary to provide a measure of reliability that will satisfy regulators and secure public acceptance. These measures are likely to be in excess of what is now provided by most water treatment systems. 3-1 CITY OF WINDHOEK, NAMIBIA The City of Windhoek is the capital of Na mibia, the most arid country in Sub- Saharan Africa. The Country has a surface area of 825,000 km 2 (319,000 mi 2 ) and has a total population of 2.2 million, making it one of the least populated countries in the world. The population of Windhoek is approximately 250,000. Since 1968, Windhoek has been adding high ly-treated reclaimed water to its drinking water supply system. The blending of reclaimed water with potable water takes place directly in the pipeline t hat feeds its potable water distribution network. The reclaimed water meets Namibia Drin king Water Guideli nes, World Health Organization Guidelines, and South Afri ca Rand Guidelines. The project is operated whereby intermediate treated water criteria have to be maintained at certain unit process. Failure to meet thes e criteria precludes the delivery of final reclaimed water into the distribution system. Treatment Process Flow Diagram The initial Goreangab Treatm ent Plant (see Figure 3-1a ), now called the “Old” Goreangab Plant, went through a series of upgrades with the last upgrade undertaken in 1997 as illustrated on Figure 3-1b. The design of the new plant is based on the experience gained over 30 years of water reclamation and reuse, but also includes new processes such as ozonation and ultrafiltration. Before the latter two processes were adopted, they were pilot tested over a 30-month period, to verify the performance with this specific raw water. 19 Figure 3-1 Water Reclamation Process Flow Diagrams at the Goreangab Water Reclamation Plant in Windhoek, Namibia. (a) original process flow diagram and (b) the new 1997 process flow diagram. Adapted from du Pisani (2005); Lahnsteiner and Lempert (2005). Lessons Learned From the Windhoek experience it is ev ident that highly treated municipal wastewater (reclaimed water) can be reused successfully for potable purposes. In the case of Windhoek, a combination of factors, with the lack of alternative water sources probably the most notable, makes DPR a viable option, even in financial terms. It is furt hermore evident that the te chnology exists to produce water reliably that meets all drinking wate r guidelines and to provide the user with an acceptable level of confidence as to the risk of DPR. 3-2 PURE CYCLE CORPORATION In the late 1970’s, the Pure Cycle Co rporation developed a complete water recycling system for the produc tion of potable drinking wate r. A number of these systems were installed in Colorado at individual homes during the period 1976 through 1982. The systems operated su ccessfully for a number of years (Harding, 2011). Ultimately, the com pany could no longer service them for financial reasons and their use was discont inued. It is interesting to note that even after the company could no longer service the systems, owners of the 20 systems petitioned the state to allow them to continue to use the water recycling systems. Treatment Process Flow Diagram The pictorial drawing of t he treatment process taken fr om the Patent issued to the Pure Cycle Corporation is shown on Fi gure 3-2. A schem atic block diagram of the process flow diagram is shown on Figure 3-3. The oper ation of the system can be described as follows. First, household wastewater is discharged to a holding tank. Then, water from the holding tank passes through a grinder (optional) and is pumped to a buffer tank which has two compartments. One compartment serves as a holding tank fo r untreated wastewater, with a capacity of one days flow, and the second serves as a holding tank for waste solids from the biological treatment pr ocess. Wastewater from the holding tank is then pumped to the biological treatment proce ss, which is compri sed of biological treatment section and a filtration section. The biological treatment section emplo ys rotating disks to which bacteria are attached (commonly known as a rotating bi ological contactor). The filter process employs rotating disks covered with a porous cloth media which serves as an effluent filter (similar to current cloth f ilters). The biologically treated and filtered wastewater is then pumped to an ultraf iltration membrane unit (or a dual bed filtration unit, as identified in the patent). Effluent from th e membrane filter is then passed through a dual bed ion-exchange co lumn, which also includes organic absorbents. Effluent from the ion exch ange process is passed through a UV unit for additional protection against pathogens before being discharged to a clean water storage tank for domestic use. A dditional details may be found in the original patent (U.S. Patent, 1979). The entire system was highly instrumented and controlled with a microprocessor with three principal elements: monitor, control, and alarm, details of whic h may be found in t he U.S. Patent. 21 Figure 3-2 Pictorial view of Pure Cycle Corporation closed water-recycling system process flow diagram (From U.S. Patent No. 4,145,279) Figure 3-3 Schematic view of Pure Cycle Corporation closed water-recycling system process flow diagram (Adapted from U.S. Patent No. 4,145,279) 22 Lessons Learned Using the unit processes available in the late 1970s, it was possible to put together a treatment syst em that produced potable drinking water from wastewater. The inclusion of a holding tank for flow equalization allowed the biological treatment process to operate at a constant flow rate, which reduced treatment variability. The biological treatment system was essentially the same as current biological treatm ent systems. The microfilt ration unit was essentially the same as used today, except there has been a significant improvement in the formulation, design, and fabrication (and, thus, effectiveness) of membranes. The ion exchange process used in the Pure Cycle system has been replaced with reverse osmosis in most recent adv anced treatment designs, although some agencies are reexamining the use of ion exchange. The Pure Cycle systems would probably still be in use if the ec onomics of servicing them were more favorable. 3-3 DENVER POTABLE REUSE DEMONSTRATION PROJECT In the period from 1985 to 1992, the City of Denver conduct ed a potable reuse demonstration project. The objective of t he project was to exam ine the feasibility of converting secondary effluent from a wa stewater treatment plant to water of potable quality that could be piped direct ly into the drinking water distribution system. The influent to the potable reuse demonstration plant was unchlorinated secondary effluent treated at the Denver Metropolitan Wastewater Reclamation District's regional wastewater treatment facility. The tr eatment processes at this facility consisted of screening, grit remo val, primary sedim entation, activated sludge, secondary sedimentation, and nitr ification for part of its influent. However, the portion fed to the demonstr ation plant was not nitrified. Final product water from the demons tration plant was never used for DPR, but stored and shown as part of the proj ect’s public outreach program. Treatment Process Flow Diagram The 3,785 m 3 (1 Mgal/d) potable reuse demonstration plant (0.38 m 3 /d [0.1 Mgal/d] after carbon adsorption) as illust rated in Figure 3-4, employed advanced 23 Figure 3-4 Treatment process flow diagram for the Denver, CO potable water reuse demonstration project (Adapted from Lauer and Rogers, 1998). treatment consisting of multiple treatm ent processes and operations to achieve the desired high constituent removal. The various processes included high-pH lime treatment, sedimentation, recarbonation, filtration, UV irradiation, carbon adsorption, reverse osmosis, air st ripping, ozonation, chloramination, and ultrafiltration. Initial tr eatment at the potable water demonstration plant consisted of aeration, followed by a high-pH lime treatment, and then by addition of ferric chloride to aid the sedimentation pr ocess. Following sedimentation, recarbonation was used to adjust the pH to approximately 7.8. A tri-media filter system followed the chemical treatment step. The filtration system removed turbidity to 0.5 NTU. Lessons Learned Conducted over a 13 year per iod, it was possible to demonstrate the reliable production of potable water from unchl orinated secondary treated municipal wastewater by means of advanced water tr eatment. The long-term operation of the research treatment facility provi ded valuable information regarding the effectiveness of various advanced water tr eatment processes for the removal of natural and anthropogenic constituents fr om water. Based on comprehensive physical, chemical and micr obiological testing, the pro duct water was found to be 24 comparable to the existing City of Denv er potable water supply. No adverse health effects were identified based on extensive toxicity and carcinogenicity studies as well as reproductive studies . A public outreach/education program was conducted as part of the project. A 1985 survey indicated that a majority of the public was not supportive of potable water reuse; however a 1990 focus group urged the utility to move forward with the project (Lohman and Milliken, 1985). Additional information on the D enver project can be found in Lauer and Rogers (1998). 3-4 INTERNATIONAL SPACE STATION To expand the International Space Station (ISS) crew size from three to six members, it was necessary to develop regenerative Environm ental Control and Life Support Systems (ECLSS). The ECLSS is comprised of the Water Recovery System (WRS) and the Urine Processor A ssembly (UPA) (Carter, 2009). These two systems are used to produce potabl e water from a combination of condensate and urine collected on ISS. Although not directly applicable to DPR of recycled water, this example is inclu ded to illustrate the range of technologies that have been applied to the pur ification of wastewater. Treatment Process Flow Diagrams The treatment process flow diagrams for the two water treatment modules on the ISS are described below. Water Recovery System A schematic of the water recovery system is shown on Figure 3-5. The WRS is used to treat condensate from the tem perature and humidity control system and distillate from the urine recover system . Water from these tw o sources is stored in a wastewater holding tank. From t he holding tank gas is removed from the water before it is pumped through a filter to remove particulate matter. Effluent from the particulate filter is next passed through filtration beds, operated on series, where inorganic and organic constituent s are removed. From the filtration beds water is passed through a catalytic reactor to remove low molecular organic constituents not removed by the filtration process. 25 Figure 3-5 Treatment process flow diagram for the treatment of condensate from the temperature and humidity control system and distillate from th e urine recovery system on the International Space Station (Adapted from Carter, 2009). Low molecular organic constituents are re moved by thermal oxidation in the presence of oxygen and a catalyst. A regenerative heat exchanger is used to recover heat from the catalytic reac tor for enhanced efficiency. A water/gas separator is to remove excess oxygen and oxidation byproducts before the process water is returned to the water distribution system. An ion exchange bed is used to remove dissolved oxidation bypr oducts from the water. Iodine is added to the water from the i on exchange bed before it is discharged to the product water storage tank. If the treated water does not meet s pecifications, the water is diverted and passed through the process again. Urine Processor Assembly A schematic of the urine tr eatment module on the ISS is illustrated on Figure 3-6. As shown, urine from the urinal facilitie s on the ISS is transferred to a wastewater storage tank. From the st orage tank urine is blended with water from the recycle filter tank. The bl ended water is transferred to the distillation unit with a positive displacement pump (i.e., peristaltic pump). Following distillation, the saturated vapor is transferred to a water gas separ ator where water is separated from the 26 Figure 3-6 Treatment process flow diagram for the treatment of urine on the International Space Station (Adapted from Carter, 2009). vapor. The condensate from the evaporat or and the water from the water/gas separator are blended and pumpe d to the water distribution system (Carter, 2009). Lessons Learned Because of the complexity of these systems, it has been a challenge to achieve long-term reliability. Following a successful demonstration period, water from the water recovery system was approved for consumption by the ISS crew in April, 2009. While the urine separ ation system can produce pot able water, it has not yet been certified because of operation diffi culties with the distillation unit and the recycle filter tank assembly. Work is currently under way to resolve the operating issues (Carter, 2009). For any future DPR projects, the le sson from the ISS systems is that use of ex isting, proven technology wo uld improve reliability. 3-5 VILLAGE OF CLOUDCROFT, NEW MEXICO The village of Cloudcroft, NM is a small mountain community, located south of Albuquerque, NM at an elev ation of 8,600 ft. The pe rmanent population is about 850, but increases to more than 2,000 during the weekends and holidays. The average water demand is about 180,000 gal/d (gallons per day) with a peak demand of about 360,000 gal/d. The water sources include springs and wells, which have experienced reduced flow s due to drought conditions. The community had resorted to water hauling on the weekends. Re cognizing that a 27 long-term alternative was needed, a plan was developed to augment the potable water system with purified (highly treat ed) wastewater. The plan involved blending 100,000 gal/d of pur ified wastewater with a slightly greater (51%) amount of spring water and/or well water. The blended water is placed in a storage reservoir (blending tank) with a det ention time of about two weeks. Water from the storage reservoir is treated bef ore being placed into the distribution system. The plant is scheduled to begin oper ation in the fall quarter of 2011. Treatment Process Flow Diagram The process flow diagram treatment is shown on Figure 3-7. As shown, the advanced wastewater treatm ent plant employs a memb rane bioreactor followed by disinfection followed by reverse osmo sis and advanced oxidation. The purified water is then blended with natural waters (spring/ground water) and placed in a blending/buffer (storage) t ank. Water from the rese rvoir is then treated by ultrafiltration, UV disinfection, passed through activated carbon, and disinfected again before being introduced into the distribution system. In reviewing the proposed treatment proce ss for Cloudcroft, it is interesting to note that many of the unit processes em ployed are similar to those employed in the OCWD system (see subsequent discussion). Figure 3-7 Schematic of Cloudcroft, NM DPR treatment process flow diagram (Adapted from Livingston, 2008). 28 Lessons Learned Acceptance of the Cloudcroft reuse syst em by the health authorities was predicated on three conditions: (1) the wa stewater had to be treated with reverse osmosis and advanced oxidation, (2) t he highly treated water had to be blended with a greater parentage (51%) of natural surface or groundwater and held in a storage reservoir, and (3) the blended water had to be treated through a water treatment plant before being introduced into the distribution system. Note that the potable water treatment system is superio r to most conventional systems due to the use of ultrafiltration (i .e., microbial barrier) and ot her barriers. Blending the highly treated water with natural water a llowed the health authorities to define the process as “indirect potable reuse.” O peration of the potabl e reuse system was to have started in the fall of 2009. Un fortunately, construction problems have delayed the completion of the project, which is now scheduled to go on line in the fall of 2011. Public enthusiasm and backing for the project remains high (Livingston, 2011). 3-6 BIG SPRINGS, TX Subject to extensive periods of limited rainfall, the communities in the Permian Basin of West Texas, have experienc ed a number of serious water supply issues. Although water reclamation has be en practiced for a long period of time, the drought conditions have forced the co mmunities to look for other water supply sources. To this end, the Colorado River M unicipal Water District (CRMWD), which supplies water to a number of cities within the basin, has undertaken an initiative to "reclaim 100% of the wa ter, 100% of the time." Key elements of the initiative are: (1) to im plement facilities to capture wastewater effluent before it is discharged, (2) to bu ild local and regional treatment facilities to reclaim the captured water, and (3) to implement facilities to blend the reclaimed water with other water supply sources. The first project to be undertaken by the CRMWD is Big Springs, TX . The plan is to capture 2.5 Mgal/d of filtered secondary effl uent, treat the effluent wit h advanced treatment, blend the treated water in the CRMWD raw wa ter transmission line, and treat the 29 blended water in the CRMWD water tr eatment plant before distribution. Construction is scheduled to commence in 2011 and facility startup is scheduled for early 2012 (Sloan et al., 2009). Treatment Process Flow Diagram The Big Springs water reclamation flow diagram is shown on Figure 3-8. As shown, the advanced wastewat er treatment plant, used to treat effluent diverted from the wastewater treatment facility, employs membrane filtration followed by reverse osmosis and advanced oxidation. The water, which has been subjected to advance treatment, is then blended with raw water in the CRMWD raw water transmission line. The blended water is then treated in a conventional water treatment facility. Concentrate (brine) from the reverse osmosis process is discharged to a brackish stream for whic h a concentrate discharge permit had to be obtained. Figure 3-8 Schematic of Big Springs, TX treatment process flow diagram (Adapted from Sloan et al., 2009). 30 Lessons Learned The important factors in the CRMWD decision to move forward with the project included: 1. Seasonality of nonpotable reuse options, which limit the volume of water that could be recycled, 2. Limited number of potentially large users, 3. Large transmission distances because of low-density development, 4. Limited landscaping due to the arid conditions, 5. High total dissolved solids (TDS) concentrations in the treated effluent, especially chloride, 6. Opportunity to recycle year round by blending with raw water sources; and 7. Alternative sources of supply ar e far away and at a lower elevation resulting in high transmission costs (Sloan et al., 2009). The implementation of this project in volved an ongoing public education program coupled with a feasibility study an d close cooperation with the Texas Commission for Environmental Quality (TCE Q). In their deli berations, the TCEQ conducted an extensive evaluat ion before accepting the pr oject. As part of the acceptance process, the TCEQ develop ed comprehensive operation, monitoring and reporting requirements, wh ich are described in their acceptance document in the form of a letter to the district. Because of the t horoughness of this document, it is included in Appendix B of this report for ea sy reference. 3-7 ORANGE COUNTY WATER DISTRICT In closing this chapter on DPR projects, it is appropriate to consider the OCWD’s groundwater replenishment system (GWRS) that went into operation in 2007. Currently, GWRS is the largest water recl amation facility of its kind in the world employing the latest advanced treatment te chnologies. The GWRS is considered here because the product water, as r eported by Burris (2010), has been studied exhaustively and determined to be highly pu rified, meeting all applicable numeric drinking water standards. 31 Treatment Process Flow Diagram The source of water for GWRS is undi sinfected secondary effluent from the Orange County Sanitation District (OCSD). The advanced water treatment facility (AWTF) process flow diagram, shown on Fi gure 3-9, includes the following unit processes: microfiltration, cartridge filtration, reverse osmosis, advanced oxidation (UV photolysis and hydrogen perox ide), carbon dioxide stripping, and lime addition. The product water is disc harged to existing spreading basins and sea water barrier injection wells. Puri fied water and other sources of dilution water introduced to the spreading basins mix with water from other sources and percolates into the groundwater aquifers , where it eventually becomes part of Orange County’s drinking water supply. Water pumped to the injection wells serves as a barrier to salt water intrus ion and also becomes part of the drinking water supply. Lessons Learned The product water from the GWRS m eets and/or exceeds, all of the CDPH requirements for potable water and the Santa Ana Regional Water Quality Control Board requirements for IPR. The performance of the facility has validated the effectiveness of the process flow di agram shown on Figure 3-9. Because of initial concerns for public acceptance and safety, an extensive public outreach program was conducted to demonstrate t he safety of GWRS product water and groundwater quality. Extensiv e monitoring on an ongoing basis is integral part to the program to assure the sa fety of the purified water. 3-8 REVIEW OF DIRECT POTABLE REUSE SYSTEMS The DPR treatment systems reviewed abov e incorporate a number of different unit processes grouped in configurations to remove the particulate, colloidal, and dissolved inorganic and organic consti tuents found in the effluent from wastewater treatment facili ties or other water source s. It should be noted that while all of the treatment processes re move dissolved organic constituents, only specific treatment processes provide fo r the removal of total dissolved solids (TDS). 32 Figure 3-9 Schematic flow diagram for 2.65 x 10 4 m 3 /d (70 Mgal/d) advanced water treatment facility at the Orange County Water District, Fountain Valley, CA The only difference between the OCWD system and a conceptual DPR system is that recycled water from the OCWD syst em is introduced into an environmental buffer for a minimum of six months, where it is presumed that it may receive some additional treatment and lose its i dentity as recycled water. However, because of the high level of purification, further treatm ent in the environment is not required. Thus, the OCWD system could, with the addition of an engineered buffer, be used for DPR, either by introduc tion into the water supply distribution system directly or to the head works of a water treatment facility. With one minor exception, the system developed for Cloudcroft, New Mexico (see Figure 3-7) is similar to the OCWD system. The principa l difference is that purified water is blended with other water supply source s in a blending tank and then treated further (to remove cont aminants added by the natural water) before introduction to the water supply distribution system. It is important to a cknowledge that the Cloudcroft design was specifically intended so that the projec t could be classified as IPR, even though arguably it could be considered a type of DPR project. The 33 distinction between IPR and DPR points out the need to further investigate the relevance of engineered storage buffers. In the future, an almost unlimited number of different configurations of unit processes could be proposed for treatment of wastewater for DPR. Because evaluating the merits of each individual c onfiguration is not within the scope of this report, the quality of the water produced using the technology used by the OCWD is proposed as a benchmark agains t which other tr eatment process configurations can be evaluated with one exception; namel y TDS, which is likely to be a site specific, project-by-project i ssue. It is clear, ho wever, that (1) the need for and size of engineered buffers, (2) system reliability, and (3) appropriate monitoring techniques will have to be evaluated for each proposed treatment process configuration. 34 4 TECHNICAL ISSUES IN DIRECT POTABLE REUSE Treated wastewater that is discharged to the environment (except for discharges to the ocean) is invariably taken up as water supply, perhaps within hours of discharge, and is referred to commonly as unplanned, or de facto , potable reuse. The effects of treatment, dilution, time, and commingling with environmental water are considered by many to be adequa te for the conversion of treated water into a potable water supply source. Conversely, planned potable reuse systems, where wastewater is processed to a qua lity suitable for water supply, are often deemed too controversial as a result of public perception and/or political considerations. However, as water supply becomes more limited, treatment technology improves, and the public becom es better informed of the nature of their local water supplies, increas ed emphasis will be placed on the planned augmentation of drinking water suppl ies with highly treated wastewater. As a result of the dev elopment and demonstration of full-scale advanced treatment processes, the use of purif ied water that has been recovered from municipal wastewater directly for potabl e purposes is now receiving increased interest as a viable alternative for DPR. It is also recognized that there is a continuum of possibilities for potable reuse ranging from direct injection into potable water distribution systems (DPR) to long-term storage in the environment prior to reuse (IPR). While the focus of this chapter is on the direct discharge (with blending) to a potable water system , the concepts are equally applicable to systems with a high recycled water contributi on (RWC) with limited retention time in the environment. It is expected that systems with short environmental retention times prior to potable reuse wi ll also need to incorporate the concepts discussed in this section. 35 The purpose of this chapter is to develop a framework for t he identification of knowledge gaps that will form the basis fo r the research topics discussed in Chapter 6. This chapter includes an intr oduction to DPR systems, a discussion of engineered storage buffers, measures to improve reliability, monitoring systems, and anticipated future developments in DPR. In addition, a su mmary review of research issues and needs for the implem entation of DPR, derived from the material presented in this chapter, is pr esented at the end of this chapter. 4-1 INTRODUCTION TO DPR SYSTEMS An overview of general water supply and treatment alternatives is shown on Figure 4-1. Direct potable reuse, as illust rated with the dark line on Figure 4-1, is inclusive of both the introduction of highly treated reclaimed water either directly into the potable water supply distri bution system downstream of a water treatment plant, or into the raw water supply immediately upstream of a water treatment plant. As shown on Figure 4-1, in addition to conventional secondary and/or tertiary facilities, the principal elements that comprise a DPR system include (1) advanced wastewat er treatment processes, (2) facilities for balancing water chemistry, (3) engineered buffers for flow retention and quality assurance, and (4) blending of purified water with other natural waters. Each of these elements is considered briefly in the fo llowing discussion. The relationship of these elements to the multip le barrier concept developed for water treatment is also considered. Advanced Wastewater Treatment Processes There has been a rapid increase in the development of technologies for the purification of water, including improvements in systems such as reverse osmosis, electrodialysis, and distillation for demineralization and the removal of trace constituents, as well as in proc esses to accomplish advanced oxidation, such as ozonation alone or with hydr ogen peroxide, UV alone or with hydrogen peroxide, and other comb inations of ozone and UV to accomplish photolysis and/or high levels of hydroxyl radi cal production. Examples of advanced treatment processes used for the removal or destruction of trace constituents 36 Figure 4-1 Summary of opportunities for direct and indirect potable reuse. The bold solid line corresponds to a system in which an engineered storage buffer is used to replace an environmental buffer. The bold dashed line corresponds to a DPR system in which an engineered storage buffer is not used. with and without reverse osmosis are shown on Figure 4-2. With the exception of flow equalization and the engineered buffer, to be discussed subsequently, the flow scheme shown on Figure 4-2a is repr esentative of the pr ocess configuration employed currently at the OCWD GWRS fo r production of potable supply. As the purified water from OCWD’s GWRS meets or exceeds all potable drinking water standards and reduces unregulated chemicals t hat are known or suspected to be 37 Figure 4-2 Potable reuse treatment scenarios: (a) process employing reverse osmosis, (b) process employing nanofiltration, and (c) process em ploying nanofiltration and electrodialysis of health concern to non-measurable or de minimus levels, it is considered to be safe for direct human cons umption (Burris, 2010). Because of the cost and logistical iss ues associated with the management of brines from reverse osmosis systems, espec ially in inland locations, there is an interest in the development of advanced processes that are able to remove or convert trace constituents without physical separation of constituents from the product water. Two proposed flow diagr ams both without reverse osmosis are shown on Figures 4-2b and 4-2c. It should be noted that the DPR system currently in use in the City of Windhoek, Namibia (see Chapter 3-2) does not use reverse osmosis. Balancing Water Chemistry Following demineralization, purified water may need to be remineralized for public health concerns (e.g. absence of magnesium and calcium), to enhance taste, to prevent downstream corrosion (e .g., calcium saturation index), and to minimize damage to soils (e.g., sodium adsorption ratio) and crops (e.g., magnesium deficiency). Balancing can be accomplished by recarbonation and addition of trace minerals and salts or by blending with other water supply sources. Proprietary blending processe s are also available. Blending with a portion of the brine is often used in seawater desalination. T he level of chemical balancing required will depend on the characteristics of the product water, the 38 volumetric blending ratio with other water sources, and the chem istry of the other water sources. Balancing of water chemistry in a DP R system could be conducted at various locations in the water system, including just prior to t he engineered storage buffer, after storage in the buffer, or after blending with al ternative supplies. It is important to verify the quality of t he chemicals used for water chemistry balancing to ensure that contaminants ar e not being introduced into the purified water inadvertently. Engineered Storage Buffer for Flow Retention and Quality Assurance Storage buffers can be environmental (i .e., natural) or engineered (i.e., constructed) facilities used between wa stewater treatment systems and potable water systems to, in general, compensate fo r process variability, reliability, and unknowns. For example, a process with a large degree of variability in product water quality may require a large buffer to allow sufficient time to detect and respond to process deficiencies prior to introduction into the potable supply. Alternately, a process t hat has a small degree of variability in product water quality (including raw source water quality) taking into consideration the level of blending with other water sources (see next section) may require only a small or no buffer facility. Both environmenta l and engineered storage buffer systems for flow retention and quality assurance are described in greater detail below. Blending with Other Water Supply Sources The amount of blending with other water supply sources will depend on a number of site-specific factors, including the availability of alternative water supply sources, regulatory requirements, and public acceptance. Like the environmental buffer, blending facilitates a loss of identity for the product water and, therefore, may diminish some public op position. However, it is important to note that blending with alternative water supply sources should not be considered to be necessary for public health protection, with the exception of mineral balance as discussed above, as it is assumed that the purified water will be of the highest quality and the alternative source water may be subject to 39 contamination if derived fr om environmental sources. It has also been proposed that blending of recycled water with other water supply sources could take place prior to introduction into an advanced treatment process, thus providing treatment purification of the entire water supply. Multiple Barriers Fundamental to the practice of planned pot able reuse is the use of multiple barriers to ensure the quality of the product water. It is important to note that the treatment systems discussed above are c onsistent with the multiple barrier concept, which has been the cornerstone of the safe drinking water program and consists of coordinated technical, oper ational, and managerial barriers that help prevent contamination at the source, enhance treatment, and ensure a safe supply of drinking water for consumers. Although no single barrier is perfect, significant protection is afforded when a number of ind ependent barriers are combined in series. Ideally, the failure of a single barrier does not result in the failure of the system. Thus, the use of mult iple barriers results in an overall high level of reliability. Based on this concept, the management, operational, and technological barriers for direct potabl e reuse shown on Figure 4-3, provides a significant level of protection from the system being out of compliance. For potable reuse applications, multiple barriers, as shown on Figure 4-3, include: (1) consumer and bus iness education, (2) source control for dischargers to the wastewater collection system, (3 ) equalization of flow and constituent concentrations and monitoring for sele cted constituents, (4) robust and redundant conventional secondary and tert iary treatment processes, (5) equalization and monitoring for enhanced proc ess reliability and detection of selected constituents (6) robust and redundant advanced treatment, and (7) an engineered buffer for quality assurance. It should be noted that conventional, tertiary, and advanced treatment contain multiple barriers within themselves. The optional conventional potable wate r treatment system, depicted on Figure 4- 3, provides a further set of barriers but is not needed unless purified water is blended with other water supplie s that require treatment. 40 Figure 4-3 Illustration of management, operati onal, and technological barriers in direct potable reuse. As noted on the diagram, the barriers associated with conventional, tertiary, advanced, and potable treatment processes are comprised of a number of individual barriers. 4-2 ENGINEERED STORAGE BUFFERS FOR FLOW RETENTION AND QUALITY ASSURANCE As noted in the introduction to this chapter, the key difference between IPR systems that employ advanced water treatment (AWT) and the proposed DPR systems is the utilization of an environmental (quality assurance) buffer, especially in the case where the purifi ed water will be added directly to the water 41 supply distribution system. For example, as described previously, the advanced treatment system in operation at the OCWD GWRS has been determined to produce recycled water that meets curr ent drinking water standards. While OCWD currently injects and percolates recycled water into a groundwater basin that serves as an environmental buffer, it is reasonable to expect that the OCWD facility could be converted to a DPR system with addition of a buffer for quality assurance. The questions that need to be addressed are (1) is it necessary to add an engineered storage buffer to replac e the environmental buffer and (2) what are the appropriate treatment per formance monitoring requirements for evaluating quality assurance. Thus, t he design and integration associated with the engineered buffer system is a ke y research area required for the development of DPR projects. Environmental buffer Environmental buffers include surface water and groundwater systems that are used for the temporary storage of recycled wa ter prior to reuse. A large natural buffer promotes a loss of identity for re cycled water, which can have an important psychological impact, time for the natural breakdown of constituents present in partially treated wastewater, and time to react to a consti tuent of concern that is detected in the water. A retention time of six months is specified in the draft CDPH regulations (CDPH, 2008) developed for indirect potable reuse through groundwater recharge using recycled water r egardless of the level of treatment (tertiary and AWT). The six-month ti me period was based on the assumption that one log of virus reduction could be achieved for each month of residence time in the groundwater aquifer, thus, achi eving an overall virus reduction of six logs. The six-log virus reduction was thought to be needed to meet public health concerns, which was relevant when tertiary effluent was being ap plied. The draft regulations also specify requirements for the initial RWC, which is limited to either 20% for tertiary treatment or 50% for AWT at project startup, with provisions for increasing the RWC, in part, based on the removal of total organic carbon (TOC) achieved during soil aquifer treatment or AWT. Requirements are in development for surface wate r augmentation using recycled water. 42 The rationale for the draft CDPH gr oundwater recharge regulations was developed during a time when analytical monitoring technology for chemical constituents was not as well developed as it is today, and TOC was used as a gross measurement of organic constituent s in the recycled water (Crook et al., 2002). Early drafts of the groundwater recharge regulations limited the organic matter of wastewater origin to 1 mg/L in the groundwater at t he point where it can be used as a drinking water source. This level was based on a recommendation of a California scientific advisory committ ee on groundwater recharge. It was the opinion of the panel that, at a TOC concent ration of 1 mg/L, the gross level of organic contamination would be reduced to levels such that there would be little chance that any specific organic chemical would be present at levels that would constitute a health hazard (State of Calif ornia, 1987). The TOC level (which is used to determine the allowable RWC) has since been reduced to 0.5 mg/L in the draft recharge regulati ons. The TOC in OCWD product water is consistently below 0.5 mg/L. The performance of curr ent wastewater tr eatment processes and their reliability have significantly im proved in recent years, as has the capability to detect and measure chemic al constituents at extremely low concentrations, and the existing st andards requiring passage through an environmental buffer for an extended period of time may no longer be warranted. When water is introduced to the environment it is subject to evaporative losses and various forms of potentia l contamination, includi ng commingling with urban and agricultural runoff, animal waste, and/or dissolution of compounds present in sediments and aquifers. It is, therefore, expected that purified water obtained from a combination of properly operated advanced tr eatment processes will result in a shift to an engineered storage buffer that provides an adequate safety factor and keeps control of the purifi ed water quality with the water agency. Another consideration related to large environmental buffers is that if a constituent is detected at levels of c oncern in the product water, a significant amount of time may be required befor e the off-speculation water can be 43 extracted fully from the buffer and retreated, discharged, or used for nonpotable applications, even after problems in t he treatment process have been corrected. Engineered Storage Buffer As described previously, when there are many unknowns and issues related to treatment reliability, it was deemed nece ssary to place treated wastewater into an environmental buffer to provide natural treatment and loss of identity, and a relatively long retention period (six months ) to allow time for corrective action in the event that the product water does not meet all regulatory requirements. However, when water is treated to a high level of purity, placement into an environmental system does not necessarily result in improved water quality, and can instead expose the purified water to potential environmental contaminants. Thus, when purified water can be produced with a system with proven performance and reliability and the quality ca n be validated rapidly, a relatively small engineered storage buffer, if any, may be sufficient for use prior to discharge directly into t he potable water system. The engineered buffer consists of a well-defined, natural or constructed, confined aquifer or storage facility. Important f eatures of the engineered buffer include: 1. Fully controlled environment, 2. Contained to prevent contamination and evaporative losses, 3. No source of contaminants from within the buffer itself, 4. Ability to divert flow out of the buffer as needed, 5. Accommodation of monito ring and sampling equipment, 6. Well-characterized and optimized hydraulics, and 7. High level of security. Several proven and conceptual engineered buffer designs are shown on Figure 4-4. As shown, the buffer can be a st andalone facility or incorporated into the transport and distribution system, depending on site-specif ic factors and needs. 44 Figure 4-4 Proven and conceptual engineered buffer systems: (a) above ground tanks, (b) covered and lined surface storage reservoirs, (c) large diameter subsurface pipelines, (d) enclosed subsurface storage reservoirs, (e) confined aquifers, (f) engineered aquifers. The specific design of the engineered storage buffer will be a function of several factors, including: 1. Site specific constraints, 2. Capabilities of t he monitoring and constituent detection system, 3. Flow rate and degree of fl ow equalization required, and 4. Required safety factors. In general, the storage requirements will be controlled by the time required for constituent analysis and overall reliabili ty of the monitoring system. Purified water must be retained in the buffer for su fficient time to validate the quality of the water for specified constituents and su rrogate measures prior to blending into a potable water system. Thus, there is a need to identify key monitoring parameters that can be eval uated expediently to veri fy system performance and product water quality. In t he event that off-speculati on product water is detected in the buffer, it would be necessary to divert the off-speculation batch to an 45 alternate (pre-determined) discharge loca tion or metered back into a specified point in the AWT treatment process. A buffer storage system composed of severa l tanks may provide a higher level of control than using a larger single storage tank; however, this scheme may result in increased monitoring and process contro l costs. For exam ple, in a system composed of four storage tanks with a m onitoring system that requires 24 hours to validate water quality, one-quarter of t he flow could be placed into one of the tanks and held until analytical results were available. One implication of the engineered buffer concept is that, with some additional infrastructure, a system like that of OCWD’s could blend the purified water directly with the area’s water supply system , allowing for greater flexibility in system operation. For example, when there are periods of purified water production in excess of the immediate potable demand, purified water could be placed into the groundwater aquifer for long-term storage and travel to remote well locations. 4-3 MEASURES TO ENHANCE RELIABILITY The conversion of existing wastewater treat ment facilities for incorporation into potable reuse systems will r equire increased scrutiny and possibly upgrades to wastewater management infrastructure and related activities. In general, conventional wastewater treatment syst ems will need to be des igned or modified to optimize their overall performance to enhance the reliability of the water purification system. Measures that can be taken to enhance the reliability of a DPR system include: enhanced source control, enhanced physical screening, upstream flow equalization, e limination of untreated return flows, switching mode of operation of biological treatment processes, impr oved performance monitoring systems, and the use of pilot test fac ilities for the ongoing evaluation of new technologies and process modifications. 46 Source Control The control of substances that are not compatible with recycled water systems is an important aspect of wate r reuse projects. Some wastewater constituents, including a variety of radionuclide s, industrial chemicals, pesticides, pharmaceuticals, and compounds found in consumer products have been found to pass through conventional wastewater treatment systems with little or no removal. The presence of these substances in recycled water, typically in trace amounts, will continue to be a significant factor in public and regulatory acceptance. These constituents also limit the applicability of recycled water or require a significant investment to remo ve during treatment. In addition, where surface waters are used as a discharge location for treated wa stewater, there is potential for detrimental ecological impacts. In its 2008 draft groundwater recharge regulations, the CDPH included a number of specific requirements for enhanced source control programs, includi ng tools to identify and rapidly address contaminants of concern and outreach programs to manage and minimize the discharge of contaminants of concern at the source. Agencies that administer source contro l programs for DPR s hould ensure that they have regulatory authority and manage ment actions under their wastewater ordinances to address constituents of conc ern. These program elements include: outreach, focused inspection, monitori ng, permitting, enforcement programs, imposition of industry-specif ic treatment or best management practices, diversion of waste, and onsite pretreatment systems that limit the discharge of difficult to treat constituents. Enhanced Fine Screening The benefits of enhanced screening include (1) removal of constituents that can impede treatment performance (e.g., solid phase oils and grease, rags, plastic materials, etc.) and (2) alte ration of the wastewater par ticle size distribution, which enhances the kinetics of biological treatment. For example, to enhance the performance of membrane bior eactors, the influent wa stewater must first be screened with an 800 μ m screen. Similar requirements should be used for 47 conventional activated sludge processes, and, especially, those used in water recycling treatment trains. Elimination of Untreated Return Flows Currently, return flows from sludge thickeners, sludge dewatering (e.g., centrifuges and belt presses), sludge stabi lization (e.g., digester supernatant), and sludge drying facilities are returned to the wastewater treatment plant headworks for reprocessing. In many in stances these return flows contain constituents that deteriorate overa ll plant performance (e.g., nitrogenous compounds, colloidal material and total dissolved solids). The presence of nitrogenous compounds in return flows often impacts the ability of the biological treatment process to achieve low levels of nitrogen, which, in turn, affects the performance of microfiltration membranes . Separate systems for the treatment of return flows are now being installed at a number of treatment plants that need to meet more stringent discharge requirements. In biologica l treatment plants to be used in conjunction with advanced treatment facilities for DPR, return flows should be processed separately. Flow Equalization Flow equalization is a method used to improve the performanc e and variability of the downstream treatment processes and to reduce the size and cost of treatment facilities. Flow equalization can occur in the secondary treatment process as illustrated on Figure 4-5 or preceding advanced treatment as illustrated previously on Figure 4-2. The principal benefits for biological wastewater treatment syst ems from flow equalizati on include: (1) enhanced biological treatment, because shock loading s are eliminated or can be minimized, spikes or high concentrations of inhibiti ng substances can be diluted, and pH can be stabilized; (2) reduced process variabi lity, (3) enhanced removal of trace constituents, (4) improved performanc e of secondary sedimentation tanks following biological treatm ent through improved consistency in solids loading; (5) reduced surface area requirements for e ffluent filtration, improved filter performance, and more uniform filter-ba ckwash cycles are possible by lower 48 Figure 4-5 Typical wastewater-treatment plant flow diagram incorporating flow equalization: (a) in- line equalization and (b) off-lin e equalization. (Adapted from Tchobanoglous et al., 2003). hydraulic loading; (6) improved operation an d reliability of disinfection systems; and (7) in chemical treatment, damping of mass loading improves chemical feed control and process reliability (Tchobano glous et al., 2003). In advanced wastewater treatment, the principal benefits include: (1 ) reduced variability of incoming water quality; (2) enhanced perform ance at constant flow operation; and (3) reduced wear and tear on membr anes caused by fluctuating flows and loads. Operational Mode for Biological Treatment To enhance the performance of advanc ed treatment facilities employing membranes and reverse osmosis, the bi ological treatment process should be operated in a nitrification or nitrification/denitrific ation mode. It has been observed that the performance of mi crofiltration membranes is enhanced significantly when wastewater has been treated in an activated sludge process operated such that nitrogen in the form of a mmonia is nitrified (oxidized). In fact, it is well established oper ationally that for a memb rane bioreactor to function properly the activated sludge process must be operated to nitrify completely. If the activated sludge process does not nitrif y completely, biological clogging of 49 the membranes can occur resulting in decreased performance and increased operational costs. Because there is a pot ential to form disinfection byproducts and N-nitrosodimethylamine (NDMA) w hen the activated sludge process is operated in either the nitrification or nitrification/denitrification mode, the process must be monitored and controlled properly. Improved Performance Monitoring The food processing industry has, over the years, applied a vari ety of techniques including the Pareto principle, preser vation and control measures, and statistical quality control charts to assure the safe ty of food products. In 1971, the hazard analysis critical control point (HACCP) c oncept was introduced to the public, food industry, and regulators. As presented in 1971, the HACCP concept was based on the following three principles, derived from work done in the late 1950s and early 1960s by the Pillsbury Company in collaboration with NA SA and the U.S. Army Natick Laboratories to develop f ood for the space program (WHO, 1997; Charisis, 2004): 1. Assessment of hazards associated with growing, harvesting processing and manufacturing, distribution, market ing, preparation, and/or use of a given raw material or food product. 2. Determination of critical control poi nts required to control any identified hazards. 3. Establishment of procedures to monitor critical control points. The HACCP method, as it is know n today, was published in 1992 and has evolved significantly from the initial form and now involves the following steps: 1. Conduct a hazard analysis, 2. Identify critical control points, 3. Establish preventive meas ures with critical limits, 4. Establish procedures to monitor critical control points, 5. Establish corrective actions, 6. Establish verification procedures, and 7. Establish record keeping procedures. 50 Over the past 40 years, the HACCP method and other sim ilar programs have been applied to a number of industries. The use of HACCP is becoming more common in the environmental field (NRMMC et al., 2006). A report delineating the application of the HACCP method fo r distribution system monitoring was prepared for the U.S. EPA in 2006 (U .S. EPA, 2006). In 2009, the WateReuse Research Foundation funded a project Utilization of HACCP Approach for Evaluating Integrity of Tr eatment Barriers for Reuse (WRF-09-03) to develop an approach for monitoring and managing micr obial water quality in reclaimed water, based on the HACCP method. The use of performance evaluation techniques such as HACCP should be a critical element of any ongoing performance monitoring and control progr am, especially when the wastewater treatment facility is producing wa ter for advance treatment for DPR. Ongoing Pilot Testing Because of the rapid development of new technologies for water purification and the limited data available to benchmar k these new technologies, it is recommended that permanent pilot scale test facilities be incorporated into the design of advanced treatment processes for DPR. In addition to the evaluation and validation of new technologies and propos ed process modifications, the pilot facilities can be used to investigate operatio nal and reliability issues that arise from time to time in the operation of full scale facilitie s. Considerations in setting up a pilot-plant test program include: (1 ) a clear understanding of the reason for conducting the pilot-plant tests (e.g., prediction of process performance and reliability), (2) the scale of the pilot plant that is required to establish performance and reliability data, (3) physical design fact ors, (4) design of the pilot testing program, and (5) nonphysical features su ch the degree of innovation involved, process complexity, and materials of construction. 4-4 MONITORING AND CONSTITUENT DETECTION While there have been a num ber of recent improvem ents in online monitoring and constituent detection, it is not, at present, feasible to provide real-time monitoring of all constituents of concern. However, the identification of surrogate 51 and indicator constituents that can be us ed to assess performance reliability of key unit processes can be used in plac e of direct measurements for all constituents of interest. Types of Monitoring The two basic types of monitoring systems that are applied are real-time and off- line. Real time measurements are used for the constant acquisition of water quality data or other process parameters and are used extensively in tracking the performance and operation of individual unit processes. For example, membrane processes may include real-time monitoring of pressure, particle size, TDS, ultraviolet absorbance (UVA), and/or TOC to assure membrane integrity. Off-line measurements are conducted in a laboratory to verify the measurements made by real-time monitoring equipment an d for the detailed characterization of individual constituents such as NDMA and 1,4-dioxane, and for different classes of constituents. Monitoring Strategies An Indicator compound is an individual constituent that represents certain physiochemical and biodegradable characterist ics of a family of constituents of concern that are relevant to fate and transport duri ng treatment. Therefore, indicators can be used to predict the pr esence or absence of other constituents provided that the indicator is removed by similar mechanisms and to the same degree as the other constit uents. A surrogate compound is a bulk parameter that can serve as a measure of performanc e for individual unit processes or operations. Some surrogate par ameters that are measured continuously, such as UVA, conductivity, and TOC, can be correla ted with the removal of individual or groups of constituents. The use of indi cators and surrogates is somewhat site specific and will need to be established for individ ual treatment operations (Drewes et al., 2010). Howe ver, after these parameter s are established they can be used to enhance the monitoring program through rapid detection programs. The ability to detect constituents of concer n rapidly will reduce the overall size of the engineered buffer facilities that are used for quality assurance. 52 Monitoring Locations Monitoring at specific locations is us ed: (1) to assess process performance and reliability, (2) for process control, and (3) to verify compliance with public health or other regulatory requirem ents. Suggested monitori ng locations are illustrated on Figure 4-6 and are summarized in Table 4-1. Monitoring at the Engineered Buffer As described previously, the engineered storage buffer is a key monitoring location because it may be the final safeguar d prior to distribution in the potable water system. Thus, the development of the monitoring program needs to be planned carefully to ensure that all constituents of importance can be assessed in the product water with sufficient s peed and accuracy to justify the size and design of the buffer facilities. It is at this point that off-speculation water would be diverted to an alternate location, such as the wastewater treat ment facility or a specified point in the purification process. 4-5 FUTURE DEVELOPMENTS IN DPR An important element for developing future DPR proj ects is defining what constitutes an acceptable treatment process train and identifying the corresponding knowledge gaps that would provide a basis for CDPH to develop implementation and approval crit eria. For purposes of this discussion only, it is assumed that any advanced treatment pr ocess train should be equipped with Figure 4-6 Representative sampling locations DPR treatment process flow diagram 53 flow equalization and monitoring of the in fluent to the advanced process as well as development of an engi neered buffer and monitori ng system for the advanced treatment-treated effluent. It is also reasonable to expect that as further advancements take place in the development of future treatment technologies and monitoring capabilities, the size of the engineered buffer can be reduced or the buffer could be eliminated. Thus, there is a need to maintain flexibility in the development of DPR regulations to accommodate the inevitable technology breakthroughs that will take place in the future. Examples of future developments are illustrated on Figure 4-7 and discussed below. Table 4-1 Summary of monitoring locations in DPR systems Monitoring location Description Process control Influent • Influent monitoring can provide data on constituents of concern that can be used to reject flow from the proces s or make process modifications that will facilitate constituent removal. • It is recommended that all advanced treatment operations incorporate on- line flow equalization facilities to facilitate flow compositing and retention while monitoring activities are conducted. Process performance and reliability Individual processes • Critical treatment operations can be mo nitored to ensure that the desired level of performance is being achieved on a continuous basis. For example, data on the rejection of TDS or TOC in a reverse osmosis system can be used to ensure that the process is meeting performance expectations and, when there is a reduction in performance, appropriate operation and maintenance activities can be implemented to maintain quality standards. Water quality assurance and compliance Effluent • Due to limitations associated with real-time monitoring systems, it is necessary to provide flow retention of the purified water to assure that the water quality has met all applicable standards prior to discharge to a potable water system. • The primary purpose of an engineered storage buffer is to retain purified water for sufficient time so that required analytical procedures needed for quality assurance can be completed and verified. 54 New Wastewater Treatment Processes With the range of research currently being conducted, it is reasonable to assume new and improved biological wastewater tr eatment processes will be developed. In the future, it is conceivable that t he activated sludge treatment process might be replaced by a series of membrane processes (see Figure 4-7a). Blending with Natural Waters Depending on the circumstances, it may be appropriate to bl end purified water with natural water before treatment by advanced water treatment facilities employing ultrafiltration and UV disinfecti on (see Figure 4-7b). The flow diagram for the Cloudcroft, NM, DPR system, as descr ibed in Section 3-5 in Chapter 3, employs this type of arrangement. New Advanced Treatment Technology As noted previously, in locations where t he cost and logistical issues associated with the management of brines from reve rse osmosis systems are overwhelming, a variety of new advanced treatment processes are currently under development for the oxidation of trace organics, without the removal of dissolved solids (see Figure 4-7c). It is lik ely that enhanced biological treatment processes will be developed to complement new types of advanced treatment technologies. Redundant Reverse Osmosis The process flow diagram shown on Figur e 4-7d, which incorporates redundant reverse osmosis processes, is present ed to demonstrate that essentially any level of reliability can be achieved with commercially available technology. With a redundant treatment step and improved m onitoring it may be possible to eliminate the need for the engineered buffer. 4-6 SUMMARY OF ISSUES FOR IMPLEMENTATION OF DPR Based on the material presented in this chapter, a number of issues can be identified that must be resolved and/or consider ed before DPR can become a reality. The principal issues are summa rized in Table 4-2. In reviewing the various issues, it is clear that a number of them are interrelated. For example, as 55 noted previously, the design and integration a ssociated with the engineered buffer system is a key research area required for the dev elopment of DPR projects. More specifically, the sizing of an engineered buffer, which could be built today, is directly related to the re sponse times for the m onitoring results to become available. With improved on-line monitoring equipment and methods, the capacity of the engineer ed storage buffer could be reduced significantly or even eliminated. Figure 4-7 Potential potable reuse treatment scenarios: (a) new biological treatment process, (b) blending with natural waters, (c) new advanced wastewater treatment technology, and (d) redundant barrier employing reverse osmosis. 56 Table 4-2 Technical issues in the implementation of direct potable reuse Consideration Comments / questions Source control • Identification of constituents that may be difficult to remove (depends on technologies used). • Development of baseline s ources and concentrations of selected constituents. • Define the improvements that need to be made to existing source control programs where DPR is to be implemented Influent monitoring • Development of influent monitoring systems, including constituents, parameters, and monitoring recommendations. • Investigate potential benefits of various influent monitoring schemes that may be used for early detection of constituents. • Consideration of how influent monitoring data could be used to adapt treatment operations depending on variable influent characteristics. Flow equalization • Determination of the optimum location and type (in- or off-line) in secondary treatment process with respect to enhanced reliability and removal of trace constituents. • Determination of optimum size of flow equalization before advanced treatment. • Quantify the benefits of flow equalization on the performance and reliability of biological and other pretreatment processes Wastewater treatment • Quantify benefits of optimiz ing conventional (primary, secondary, and tertia ry) processes to impr ove overall reliability of entire system. • Quantify the benefits of complete ni trification or nitrification and denitrification on the performanc e of membrane systems used for DPR applications Performance monitoring • Determine monitoring schemes to document reliability of treatment performance for each unit process and validate end- of-process water quality. Analytical/monitoring requirements • Selection of constituents a nd parameters that will require monitoring, including analytical methods, detection limits, quality assurance/quality control methods, and frequency. • Determination of how monitoring systems should be designed in relation to process design. • Development of appropriate monitoring systems for use with alternative buffer designs. Advance wastewater treatment (water purification) • Develop baseline data for tr eatment processes employing reverse osmosis. OCWD can be used as a benchmark. • Development of alternative treatment schemes with and without demineralization that can be used for water purification. • Quantify benefit of second stage (redundant) reverse osmosis. Continued on following page 57 Table 4-2 Continued Consideration Comments / questions Engineered storage buffer • Development of sizing guidelines based principally on existing analytical, detection, and monitoring capabilities to assess technical and economic feasibilit y of utilizing engineered storage buffer. • Characterize the impact of existing monitoring response times on the safety and economic feasibility of implementing an engineered storage buffer. Balancing mineral content • Development of recommendations for balancing water supply mineral content in consideration of site-specific factors, such as magnesium and calcium. • Determination of potential impacts of various water chemistries on infrastructure and public acceptance. • Development of specifications for chemicals used for balancing water quality. Blending • Development of guidance on what level of blending, if any, is required based on the quality of the purified water and alternative water sources. • Investigation of the significanc e of and rationale for blend ratios in terms of engineered buffer, protection of public health, public acceptance, and regulatory acceptance. • Investigation of potential impac ts of purified water on drinking water distribution system, e.g., corrosion issues, water quality impacts, etc. Emergency facilities • Stand-by power systems in the event of power loss or other emergency. • Availability of all replacement parts and components that would be required in the event of a process breakdown. • Process redundancy so that treatment trains can be taken off- line for maintenance. • Facilities for the by-p ass or discharge of off-speculation water in the event that the water does not meet the established quality requirements. Pilot testing • Utilization of a review panel for advice and recommendations on the design, operation, monitoring plan for a project’s pilot system to ensure that it will be representative of the proposed full-scale system. • Development of monitoring protocol for collection of baseline data for “raw” water input to AW T pilot plant; how much testing and for what duration (e.g., 6 mo. to 1 yr.). • Development of pilot study design so that results can be used to assess reliability with proposed source water. 58 5 PUBLIC ACCEPTANCE ISSUES IN DIRECT POTABLE REUSE The purpose of this chapter is to revi ew past and current knowledge on public acceptance of DPR. This review is bas ed on information available from ongoing or planned DPR projects, the 2009 WRRF Research Needs Workshop (WRRF, 2009), the white paper by Nellor and M illan (2010), and the report on the 2010 Direct Potable Reuse Workshop (CUWA et al., 2010). Research needs in public acceptance issues that must be addressed if DPR is to be a viable water supply option are given in Sections 6-6 th rough 6-8 in the following chapter. 5-1 PUBLIC PERCEPTION OF DPR PROJECTS Background information on the Windhoek, Cloudcroft, and Big Springs DPR projects was provided in Chapter 3. A combination of factors has made DPR a viable option for each of t hese communities, with the lack of alternative water supply sources being the most notable. Other important factors in the development of these DPR projects include availability of advanced water treatment technologies, monitoring, im proved water quality, emergency shutdown capabilities, and public out reach/acceptance. For the two projects being implemented in the U.S., DPR was accepted without dispute. Outreach for Cloudcroft incl uded public meetings, involvement with wastewater master planning and implement ation, Village Council meetings, and ensuring that business leaders underst ood the need for the project, with the result that there was broad support for the project (L ivingston, 2008). Outreach for Big Springs included public meetings, radio interviews with call-in, newspaper articles, and use of the internet to highlight water scarcity and the need for improved water quality and to describe t he proposed reclamation concept (Sloan et at., 2010). The public out reach effort in Big Springs is ongoing. To date, 59 public reaction to the Big Springs DPR project has been generally positive or at least neutral. The role of unplanned, or de facto , potable reuse in the context of planned potable reuse was discussed in Chapter 4. Often, communi ties considering potable reuse are unaware of the role of unplanned reuse in their overall water supply. The purpose of WateReuse Research Foundation Project “Effect of Prior Knowledge of ‘Unplanned’ Potable R euse on the Acceptance of ‘Planned’ Potable Reuse ” (WRF-09-01) is to evaluate how acceptance of planned potable reuse changes when people are inform ed about the long history and everyday reality of unplanned potable reuse. The project, to be completed in 2012, is designed to address both IPR and DPR, t hereby providing insight into the relationship between public acceptance with or without an environ mental buffer. 5-2 CHALLENGES FOR DIRECT POTABLE REUSE A number of challenges related to public perception and acceptance of DPR in California have been identified based on (1 ) a review of prior studies regarding public opinion and strategies about pot able reuse; (2) what has been learned from successful and unsuccessful IPR pr ojects; (3) what has been learned about communicating with the public regarding constituents of emerging concern (CEC) such as pharmaceuticals, personal care products, and endocrine disrupting chemicals; and (4) recommendations from experts with experience on planning and implementing IPR projects (Nellor and Millan, 2010). O ne of the primary conclusions of the review was that DPR is expected to face the same public acceptance challenges faced by IPR. Contingent on CDPH appr oving regulations that would allow DPR, the following four challenges should be addressed prior to seeking public support for DPR: 1. The water reuse community must it self support DPR before seeking public acceptance. At the present time, support within the California water reuse community is not universal, which will confound efforts to request public support. 60 2. A standard public involvement pr ogram should be developed for potable reuse that builds on lessons learned from IPR projec ts, research regarding CEC risk communications, and current efforts on how to communicate about water, including terminology and messages. This challenge will be aided by WRF-07-03 (“Talking about Wate r – Vocabulary and Images that Support Informed Decisions about Wate r Recycling and Desalination”) that is (1) assessing the influence of words, images and concepts on the public perception of recycled water; (2 ) identifying preferred terminology; and (3) determining if improved knowledge and understanding of the water cycle, water science, and technology improves acceptance. This study is scheduled to be completed in June 2011. 3. Public outreach/participation t ools should be developed to provide a complete picture of the water cycle, including the ubiquitous presence of CECs and their relative risk. Agreement must be reached among the water reuse community about how to explain the water cycle and the role of water reuse, and to communicate effectively about perceived risks. As discussed in Chapter 3, while advanc ed water treatment technologies can remove constituents of concern to low and what are believed to be insignificant levels with regard to human health, the public and regulators still consider CECs to be an issue that must be addressed for DPR, particularly in terms of relative risk. 4. California will need to develop regulat ions for DPR before projects can move forward and be embraced by the public. Even if technology can be proven safe, technology in the absence of regulatory oversight and controls can catalyze mistrust an d fear, even though purified water is known to be safe. 5-3 IMPLEMENTATION STRATEGIES FOR DIRECT REUSE Participants at the 2010 Direct Reuse Wo rkshop identified five tasks as the highest priorities in addressing public a cceptance issues related to implementing DPR in California as shown in Table 5-1. 61 Table 5-1 Public acceptance issues in the impl ementation of direct potable reuse Issue Description Possible Resources a Develop appropriate terminology • Develop water recycling terminology that is understandable by stakeholders and consistent with regulations to instill credibility and product confidence. • Examples where resolution of key terms is needed include product water, non-potable reuse, and direct versus indirect potable reuse. • WRF-07-03 (“Talking about Water – Vocabulary and Images that Support Informed Decisions about Water Recycling and Desalination”) Survey stakeholders • Identify stakeholders. • Determine purpose of surveys. For example how the public differentiates between DPR and IPR; the role of natural treatment and environmental buffers in public acceptance; opposition to DPR; why the public accepts DPR. • Develop survey questions. • WRF-09-01 (“Effect of Prior Knowledge of ‘Unplanned’ Potable Reuse on the Acceptance of ‘Planned’ Potable Reuse”) Develop messages • Use agreed upon terminology and information obtained from stakeholder surveys. • Identify audience (should include supporters, opponents, water reuse community, water community). • Identify key objectives and contents of messages. • Hawley et al., 2008 • WRF-09-07 (“Risk Assessment Study of PPCPs in Recycled Water to Support Public Acceptance”) Develop a communications strategy • Determine when to initiate outreach so that efforts are proactive and consider all supply alternatives. • Incorporate experience learned from successful and unsuccessful potable reuse projects and other critical factors. • Identify the types of information and methods of communication that will be most useful. • Identify strategies for community leaders/decision makers and the press. • Identify strategies to work with opponents. • WRF-01-004: An interactive website to help community's plan and introduce potable reuse projects Implement the communications strategy • Use the information developed by the prior tasks. a Descriptions for WateReuse Research Foundation projects are available at: http://www.watereuse.org/sites/defaul t/files/u8/Total_Project%20List101910.pdf . 62 6 RESEARCH NEEDS IN DIRECT POTABLE REUSE Issues that must be cons idered in the implementati on of DPR were identified previously in Table 4-2 and Table 5-1. From the list of issues identified in Tables 4-2 and 5-1, eight have been selected as bei ng the most critical with respect to the development of guidance for eval uating and, if appropr iate, implementing DPR. Five of the eight proposals are technology based and three are related to public acceptance. For these eight, draft research proposals have been prepared and are presented below. It is ant icipated that if these proposals are developed into full RFPs, they would be modified and expande d consistent with the research program of the WateReuse Research Foundation and/or other funding organizations. The spec ific research topics are: 1. Sizing of engineered storage buffer, 2. Treatment tr ain reliability, 3. Blending requirements, 4. Enhanced monitoring techniques and methods, 5. Equivalent advanced treatment trains, 6. Communication resources for DPR, 7. Acceptance of direct potable reuse, and 8. Acceptance of potable reuse. 6-1 RESEARCH TOPIC: SIZING OF ENGINEERED STORAGE BUFFER Full Title Design Considerations for Sizing Engineered Storage Buffers Rationale The availability of an engin eered storage buffer is a key element in direct potable reuse, using current treatment and m onitoring techniques. The engineered buffer is designed to provide a final monitori ng point where the water quality can be 63 validated for potable reuse before being intr oduced either directly into the potable water supply distribution system downstr eam of a water treatment plant. The engineered storage buffer must be of su fficient capacity to allow for the measurement of specific constituents to be assured that the quality of water provided meets all applicab le public health standards. An engineered storage buffer may not be needed where the purified water is blended with the raw water supply immediately upstream of a water treatment plant. Engineered buffers can be placed at any point in the water purificat ion process, but are essential prior to introduction into the potable water distribution system, based on current technology. In the future, with enhanced treatment reliability measures and monitoring techniques, an engineered st orage buffer may not be necessary. Objectives The specific objectives of this proposed research project are to: 1. Develop procedure and guidance for the design of engineered storage buffers based on current treatment performance, reliability, analytical, detection, and monitoring capabilities. 2. Develop operational strategies fo r managing off-speculation product water. 3. Define the impact of monitoring respons e times for selected constituents on the economic feasibility of im plementing an engineered buffer. 4. Evaluate the design of monitoring syst ems that can be used to minimize the size of the engineer ed storage buffer. Benefits The engineered storage buffer is the final remaining piece of infrastructure needed in the development of direct potable reuse systems using current treatment and monitoring techniques. Reduc ing the volumetric capacity of the storage buffer to a reasonable size will allo w for the recycling of large amounts of water, both in locations that do not have either suitable gr oundwater aquifers or surface storage reservoirs of sufficient c apacity to comply with existing retention time requirements, and when DPR has been determined to be the most technically and economically viable option. 64 6-2 RESEARCH TOPIC: TR EATMENT TRAIN RELIABILITY Full Title Impacts of Treatment Trai n and Process Operation Modifications to Enhance the Performance and Reliability of Secondary, Tertiary, and Advanced Treatment Systems Rationale Enhanced screening, flow equaliza tion, the eliminat ion of untreated return flows, and switching from conventiona l to nitrification/denitrif ication mode of operation of the activated sludge process are proc ess modifications that can be used to improve the performance and variability of the downstream biological treatment processes and to reduce the size and co st of treatment facilities. Objectives The specific objectives of this proposed research project are to: 1. Assess the benefits of improved screeni ng of raw wastewater on biological treatment reliability and performance. 2. Determine the optimum location and type (in-line or off-line) of flow equalization with respect to performance and reliability of biological treatment processes. 3. Determine the impact of flow equalizati on on the biological removal of trace constituents. 4. Determine the impact of switchin g from conventional to NDN mode of operation of the activated sludge pr ocess on the removal of trace constituents. 5. Assess the impact on process variabili ty and reliability of eliminating the return of untreated return flows, especially on nitrif ication and denitrification. 6. Determine the optimum size of flow equalization before advanc ed treatment if influent flow equalization is not used. Benefits Although each of the interventions cit ed above will have benefits, the impact of flow equalization and the removal of unt reated return flows is perhaps the greatest. The principal benefits of flow equalization and the removal of untreated 65 return flows for biological wastewater treatment systems include: (1) enhanced biological treatment, because shock loading s are eliminated or can be minimized, inhibiting substances can be diluted, and pH can be stabilized; (2) reduced process variability, (3) enhanced removal of trace constituents, (4) improved performance of secondary sedimentation tanks following biological treatment through improved consistency in solid s loading; (5) reduced surface area requirements for effluent filtration, improved filter performance, and more uniform filter-backwash cycles are possible by lower hydraulic loading; and (6) in chemical treatment, damping of mass l oading improves chemical feed control and process reliability. In advanced wastew ater treatment, the principal benefits include: (1) reduction or elimination of shock loading, (2) enhanced performance at constant flow operation, and (3) r educed wear and tear on membranes caused by fluctuating flows and loads. 6-3 RESEARCH TOPIC: BLENDING REQUIREMENTS Full Title Evaluation of Blending Require ments for Purified Water. Rationale The amount of blending with other water supply sources will depend on a number of site specific factors, including the availability of alternative water supply sources, regulatory requirements, and pub lic acceptance. Blending, like the use of an environmental buffer, facilitates a loss of identity for the product water and, therefore, may diminish some public opposition. However, it is important to note that blending with alternative water supply sources should not be considered to be necessary for water quality improvement as it is assumed that the recycled water will be of the highest quality and t he alternative source water may be subject to contamination if derived from environmental sources. Depending on the circumstances, it may be appropriate to blend tertiary effluent with natural water before treatment by advanced water treatment facilities employing reverse osmosis and advance oxidation. 66 Objectives The specific objectives of this proposed research project are to: 1. Develop guidance on what level of blending, if any, is required based on purified water quality and different water sources. 2. Assess various blend ratios and rationale for high blend rates. 3. Assess potential impacts of purified water on drinking water distribution systems (e.g., corrosion issues). 4. Develop recommendations for balanc ing water supply mineral content in consideration of site-specific factors, such seasonal water quality changes in alternative water supply sources. 5. Determine potential impacts of various water chemistries on infrastructure and public acceptance. 6. Develop specification for chemic als used for balancing water quality. Benefits The principal benefits of this research ar e to define the crit eria and requirements for blending reverse osmosis purified water with other water supply sources of varying water quality in DPR applications to meet specific water quality objectives. 6-4 RESEARCH TOPIC: ENHANC ED MONITORING TECHNIQUES AND METHODS Full Title Enhanced Monitoring Techniques and Me thods for Direct Potable Reuse Rationale As described previously, the engineered storage buffer is a key monitoring location because it may be the final barrier prior to distribution in the potable water system. Thus, the development of the monitoring program needs to be planned carefully to ensure that all constituents of importance can be assessed in the product water with sufficient s peed and accuracy to justify the size and design of the buffer facilities. It is at this point that off-speculation water could be diverted to an alternate location, such as the wastewater tr eatment facility, a 67 specified point in the purific ation process, or to a site where the water could be used for a nonpotable application. Objectives The specific objectives of this proposed research project are to: 1. Determine constituents and parameters t hat will require monitoring, including analytical methods, time to obtain resu lts, reliability of method, detection limits, and frequency. 2. Determine how monitoring systems should be designed in relation to process design. 3. Develop appropriate monitoring sy stem for use with alternative buffer designs. 4. Evaluate monitoring techniques and surrogate parameters used in other industries utilizing high purity wate r for use in DPR applications. 5. Pilot test selected monitoring techniqu es for DPR applications, if appropriate. Benefits The principal benefit would be to allo w the design of engineered buffers of reasonable size to facilitate the reuse of significant amounts of water now discharged to the ocean (or elsewhere). Discharge of water to the ocean will become of greater concern as it is anticipated that 80% of the world’s population will live within 200 km (124 mi) of a coastal area by 2025. 6-5 RESEARCH TOPIC: EQUIVALE NT ADVANCED TREATMENT TRAINS Full Title Equivalency of Advanced Wastewater Treat ment Trains and Processes for Direct Potable Reuse Rationale As noted previously, in locations where t he cost and logistical issues associated with the management of brines from reve rse osmosis systems are overwhelming, a variety of new advanced treatment pr ocesses are currently under development for the oxidation of trace organics and select ive demineralization. It is likely that 68 enhanced biological treatment processes will be developed to complement new types of advanced wastewater treatment technologies. Objectives The specific objectives of this proposed research project are to: 1. Develop baseline data and criteria for treatment pr ocesses employing reverse osmosis (e.g., OCWD can be used as a benchmark). 2. Develop alternative treatment schem es, with and without demineralization, that can be used for the production of purified water for DPR. 3. Evaluate alternative treat ment trains with respect to constituent removal, economics, process residuals, reliability, and long-term sustainability. Benefits The development of equivalen cy criteria will make it possi ble to apply a variety of alternative treatment technologies, curr ently available and/or under development, for DPR. The availability of non-re verse osmosis processes for advanced treatment will be of great benefit to inland communities seeking to implement DPR. 6-6 RESEARCH TOPIC: COMMUNICATION RESOURCES FOR DPR Full Title Develop Standard Terminology, Messaging, and Communication Materials for Planning and Implementation of DPR Rationale Implementation of DPR at the statewide level requires discussion and buy-in from policy makers, legisl ators, regulators, and the public. Prior to engaging in this dialog, it will be necessary to develop standardized terminology, and effective messaging and communicati on materials that can be used in discussions regarding DPR and its role as part of the California water supply. Standardized terminology is needed because, at present, different agencies tend to use different terms when describing the same concept related to water reuse, and, especially, with respect to DPR and IP R. Based on public opinion studies, the use of appropriate terminology and clear communication (e.g., messaging) 69 are of fundamental importance with regard to public acceptance of potable reuse. Based on preliminary results from WR F 07-03, it has been found that the greatest change in public opinion, t hat occurred with clear knowledge and understanding about water quality, was the acceptance of DPR. Regrettably, water industry communications are full of technical jargon and fail to put water use and reuse in perspective. This failure in communication creates a situation where it is easy to confuse the public about what is being communicated and it is also easy to stigmatize water’s quality by the history of where it once was rather than the fact that it is safe to drink. Objectives 1. Develop standardized terminology for water reuse including DPR and IPR that is understandable by stakeholders and consistent with regulations to instill credibility and product confidence. 2. Use the outcome of the terminology and public perception research to develop the effective messaging and comm unications materials for different stakeholders. 3. The communication materials should also include information that can be used to develop functional outreach materials. 4. To ensure that the information developed is pertinent for use in California and takes into consideration how Californians prefer to receive information, focus group testing or surveys may be needed 5. Conduct workshops with the Californi a water industry to ensure cooperative use of the material developed. Benefits Development of standardized terminology and effective communication materials will enable communities in California to understand the conc ept of DPR. The information developed in this project will also be vital for outreach and policy decisions regarding DPR. This project would build on the results of WRF-07-03, “Talking about Water: Words and Images that Can Enhance Public Acceptance of Water Recycling and Desalination ”, and WRF-09-01, “Effect of Prior 70 Knowledge of ‘Unplanned’ Potable R euse on the Acceptance of ‘Planned’ Potable Reuse .” 6-7 RESEARCH TOPIC: ACCEPTANCE OF DIRECT POTABLE REUSE Full Title California Direct Potable Reuse Summit Rationale Currently there is disagreem ent within the California water community (water and wastewater) about pursuing DPR based on (1 ) skepticism that DPR is a viable option, (2) concern about potential negative backlashes on ongoing IPR projects, (3) concern that this effort will direct f unds away from non-potable reuse projects, and (4) a belief that it’s not safe to dire ctly drink recycled water with or without an engineered storage buffer. The summit will build on discussions held at the 2010 Direct Potable Reuse Workshop, but will be directed specifically at “policy grounding” and to consolidate and/or clar ify the water industry’s positions regarding DPR. Objectives 1. Bring together California water pr ofessionals for facilitated policy level discussions regarding areas where t here may be agreement or disagreement regarding the value or need for DPR as a part of the state’s water supply portfolio. This activity is envisioned as a 1 to 2 day meeting with about 20 participants and a facilitator. 2. Participants will be invited that have different perspectives about the value and viability of DPR in California, including California water industry professionals, advisors to politicians and water industry professions, public health regulators, and elected offici als that serve on water agency boards. 3. Develop a position statem ent on DPR in California. 4. Establish a framework for revisiti ng the position statement over time. Benefits This effort is important as it will be unlik ely that the public will support a concept that is not supported (or at least not opposed) by the water community. It can 71 also aid in the formation of alliances and the identification of potential sources of funding/support for research and the development of information on DPR implementation. 6-8 RESEARCH TOPIC: ACCEPT ANCE OF POTABLE REUSE Full Title Effect of Prior Knowledge on the Acc eptance of Planned Potable Reuse in California Rationale This project would add a second phase to WRF-09-01, “Effect of Prior Knowledge of ‘Unplanned’ Potable R euse on the Acceptance of ‘Planned’ Potable Reuse ”, to provide information specific to California public perceptions of potable reuse. The scope of WRF-09-01 is limited to unplanned potable reuse via surface water, IPR via surface wate r, and DPR without an engineered storage buffer; California is not included as part of the focus group testing or survey research. The proposed study would add a second phase WRF-09-01 to determine how acceptance of planned potable reuse changes when people are informed about the long history and everyday reality of unplanned potable reuse in California. The study would use and modify the material s and methodologies developed for WRF-09-01 and apply them to communities in California for water supplies derived from surface water and groundwater. The scenarios tested would include unplanned pot able reuse (surface water and groundwater), IPR (groundwater recharge and surface wa ter augmentation), and DPR (with and without an engineered storage buffer). It will provide insight of public perceptions regarding different models of potable reuse. Objectives 1. Modify background explanation of the water cycle developed for WRF-09-01 to address unplanned potable reuse via surface water and groundwater. 2. Develop real-world un planned potable reuse scenar ios for California that address surface water and groundwater. 72 3. Develop scenarios for unpl anned potable reuse, IPR, and DPR to be tested by two to three focus groups in differ ent California communities. Each focus group would consist of one sub-group t hat receives background information on the water cycle and one sub-group that does not. 4. Based on the outcome of focus groups , conduct survey research to validate whether the conclusions drawn from the focus group meetings can be considered representative of t he broader public in California. Benefits The results of this study would help to clarify whether communities considering the use of recycled water for potable r euse (both IPR and DPR) would be more accepting of water recycling if they had prior knowledge and understanding of ‘unplanned’ water reuse via discharges of treated wast ewater into water supply sources. This project will, therefore, either validate or refute the proposition that information and messages related to prior knowledge of consumption of wastewater in drinking water via unplan ned reuse enhances or effects public acceptance of planned IPR and DPR. The results of this study will also be used to assess whether communities are more willing to accept potable reuse if it involves environmental buffers and/or engineered storage buffers. 73 REFERENCES Anderson, P., N. Denslow, J.E. Drewes, A. Olivieri, D. Schlenk, and S. 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Milliken (1985) "Inf ormational/Educational Approaches to Public Attitudes on Potable Reuse of Wastewater," Denver Research Institute, Denver, CO. Nellor, M.H. and Millan, M. (2010) Public and Political Acceptance of Direct Potable Reuse , WateReuse California, Sacramento, CA. NRMMC, EPHC, and HLMC (2006) National Guidelines for Water Recycling: Managing Health and Environmental Risks , Natural Resource Management Ministerial Council, Envir onment Protection and Heritage Council, and Australian Health Mi nisters’ Conference, Australia. Richardson, T. (2011) Personal communication with D. Smith. Sloan, D.W., Wingert, C., and Cadena, I. (2010) “Potable Reuse in the Permian Basin.” Presented at the 25 th WateReuse Symposium, Washington, D.C. 75 State of California (1987) Report of the Sc ientific Advisory Panel on Groundwater Recharge with Reclaimed Wastewater . Report prepared for the State of California, State Water Resources Control Board, Department of Water Resources, and Department of Health Services, Sacramento, California. SWRCB (2009). Water Recycling Policy. California State Water Resources Control Board, Sacramento, California. http://www.swrcb.ca.gov/water_issues /programs/water_recycling_policy/doc s/recycledwaterpolicy_approved.pdf SWRCB (2011). California Water Code. California State Water Resources Control Board, Sacramento, California. (http://www.leginfo.ca.gov/cgibin/calawquery?codesection=wat&codebody= &hits=20) Taffler, D., D. Lesley, and A. Zelenka (2008) “Hidden Potential – Recycled Water and the Water-Energy-Carbon Nexus,” Water Environment & Technology. 11, 20. Tchobanoglous, G., F.L. Burton, and H.D. Stensel (2003) Wastewater Engineering: Treatment and Reuse , 4th ed., Metcalf and Eddy, Inc., McGraw-Hill Book Company, New York. U.S. EPA (1975) Research Needs for the Potable Reuse of Municipal Wastewater , EPA-600/9-75-007, U.S. Environmental Protection Agency, Cincinnati, OH. U.S. EPA (1980) Report of Workshop Proce edings: Protocol Development: Criteria and Standards for Potable Reuse and Feasible Alternatives , EPA- 570/9-82-005, U.S. Environm ental Protection Agency, Office of Drinking Water, Washington, DC. U.S. EPA (2006) Hazard Analysis Critical Control Point (HACCP) Strategies for Distribution System Monitoring, Ha zard Assessment and Control, Office of Ground Water and Drinking Water, Standards and Risk Management Division U.S. Environmental Protection Agency, Washington DC U.S. Patent (1979) U.S. Patent number 4,145,279, i ssued on Mar. 20, 1979, US Patent Office, Washington DC. WHO (1997) HACCP–Introducing the Hazard Analysis and Critical Control Point System , World Health Organization Geneva, Switzerland. WRRF (2009) Research Needs Workshop , WateReuse Research Foundation, Alexandria, VA.                                                                                 Appendix A Text: Senate Bill 918   78 Senate Bill No. 918 An act to amend Sections 13350 and 13521 of, and to add Chapter 7.3 (commencing with Section 13560) to Division 7 of, the Water Code, relating to water recycling. LEGISLATIVE COUNSEL’S DIGEST SB 918, Pavley. Water recycling. (1) Existing law establishes the State Water Resources Control Board and the California regional water quality control boards as the principal state agencies with authority over matters relating to water quality. Existing law requires the State Department of Public Health to establish uniform statewide recycling criteria for each varying type of use for recycled water where the use involves the protection of public health. This bill would require the State Department of Public Health to adopt uniform water recycling criteria for indirect potable water reuse for groundwater recharge, as defined, by December 31, 2013. The bill would require the department to develop and adopt uniform water recycling criteria for surface water augmentation, as defined, by December 31, 2016, if a specified expert panel convened pursuant to the bill finds that the criteria would adequately protect public health. The bill would require the department to investigate the feasibility of developing uniform water recyc ling criteria for direct potable reuse, as defined, and to provide a final report on that investigation to the Legislature by December 31, 2016. The bill would require the department, in consultation with the State Water Resources Control Board, to report to the Legislature from 2011 to 2016, inclusive, as part of the annual budget process, on the progress towards developing and adopting the water recycling criteria for surface water augmentation and its investigation of the feasibility of developing water recycling criteria for direct potable reuse. The bill would require the State Water Resources Control Board to enter into an agreement with the department to assist in implementing the water recycling criteria provisions. (2) Existing law imposes specified civil liabilities for violations of water quality requirements, and requires all funds generated by the imposition of those liabilities to be deposited in the Waste Discharge Permit Fund. Existing law requires these moneys to be expended by the State Water Resources Control Board, upon appropriation by the Legislature, to assist California regional water quality control boards and other public agencies in cleaning up or abating the effects of waste on waters of the state. This bill would require those funds to additionally be made available, upon appropriation by the Legislature, to the state board for purposes of assisting with the development and adoption of the water recycling criteria. The people of the State of California do enact as follows: SECTION 1. Section 13350 of the Water Code is amended to read: 13350. (a) A person who (1) violates a cease and desist order or cleanup and abatement order hereafter issued, reissued, or amended by a regional board or the state   79 board, or (2) in violation of a waste discharge requirement, waiver condition, certification, or other order or prohibition issued, reissued, or amended by a regional board or the state board, discharges waste, or causes or permits waste to be deposited where it is discharged, into the waters of the state, or (3) causes or permits any oil or any residuary product of petroleum to be deposited in or on any of the waters of the state, except in accordance with waste discharge requirements or other actions or provisions of this division, shall be liable civilly, and remedies may be proposed, in accordance with subdivision (d) or (e). (b) (1) A person who, without regard to intent or negligence, causes or permits a hazardous substance to be discharged in or on any of the waters of the state, except in accordance with waste discharge requirements or other provisions of this division, shall be strictly liable civilly in accordance with subdivision (d) or (e). (2) For purposes of this subdivision, the term “discharge” includes only those discharges for which Section 13260 directs that a report of waste discharge shall be filed with the regional board. (3) For purposes of this subdivision, the term “discharge” does not include an emission excluded from the applicability of Section 311 of the Clean Water Act (33 U.S.C. Sec. 1321) pursuant to Environmental Protection Agency regulations interpreting Section 311(a)(2) of the Clean Water Act (33 U.S.C. Sec. 1321(a)(2)). (c) A person shall not be liable under subdivision (b) if the discharge is caused solely by any one or combination of the following: (1) An act of war. (2) An unanticipated grave natural disaster or other natural phenomenon of an exceptional, inevitable, and irresistible character, the effects of which could not have been prevented or avoided by the exercise of due care or foresight. (3) Negligence on the part of the state, the United States, or any department or agency thereof. However, this paragraph shall not be interpreted to provide the state, the United States, or any department or agency thereof a defense to liability for any discharge caused by its own negligence. (4) An intentional act of a third party, the effects of which could not have been prevented or avoided by the exercise of due care or foresight. (5) Any other circumstance or event that causes the discharge despite the exercise of every reasonable precaution to prevent or mitigate the discharge. (d) The court may impose civil liability either on a daily basis or on a per gallon basis, but not on both. (1) The civil liability on a daily basis shall not exceed fifteen thousand dollars ($15,000) for each day the violation occurs. (2) The civil liability on a per gallon basis shall not exceed twenty dollars ($20) for each gallon of waste discharged. (e) The state board or a regional board may impose civil liability administratively pursuant to Article 2.5 (commencing with Section 13323) of Chapter 5 either on a daily basis or on a per gallon basis, but not on both. (1) The civil liability on a daily basis shall not exceed five thousand dollars ($5,000) for each day the violation occurs.   80 (A) When there is a discharge, and a cleanup and abatement order is issued, except as provided in subdivision (f), the civil liability shall not be less than five hundred dollars ($500) for each day in which the discharge occurs and for each day the cleanup and abatement order is violated. (B) When there is no discharge, but an order issued by the regional board is violated, except as provided in subdivision (f), the civil liability shall not be less than one hundred dollars ($100) for each day in which the violation occurs. (2) The civil liability on a per gallon basis shall not exceed ten dollars ($10) for each gallon of waste discharged. (f) A regional board shall not administratively impose civil liability in accordance with paragraph (1) of subdivision (e) in an amount less than the minimum amount specified, unless the regional board makes express findings setting forth the reasons for its action based upon the specific factors required to be considered pursuant to Section 13327. (g) The Attorney General, upon request of a regional board or the state board, shall petition the superior court to impose, assess, and recover the sums. Except in the case of a violation of a cease and desist order, a regional board or the state board shall make the request only after a hearing, with due notice of the hearing given to all affected persons. In determining the amount to be imposed, assessed, or recovered, the court shall be subject to Section 13351. (h) Article 3 (commencing with Section 13330) and Article 6 (commencing with Section 13360) apply to proceedings to impose, assess, and recover an amount pursuant to this article. (i) A person who incurs any liability established under this section shall be entitled to contribution for that liability from a third party, in an action in the superior court and upon proof that the discharge was caused in whole or in part by an act or omission of the third party, to the extent that the discharge is caused by the act or omission of the third party, in accordance with the principles of comparative fault. (j) Remedies under this section are in addition to, and do not supersede or limit, any and all other remedies, civil or criminal, except that no liability shall be recoverable under subdivision (b) for any discharge for which liability is recovered under Section 13385. (k) Notwithstanding any other law, all funds generated by the imposition of liabilities pursuant to this section shall be deposited into the Waste Discharge Permit Fund. These moneys shall be separately accounted for, and shall be expended by the state board, upon appropriation by the Legislature, to assist regional boards, and other public agencies with authority to clean up waste or abate the effects of the waste, in cleaning up or abating the effects of the waste on waters of the state, or for the purposes authorized in Section 13443, or to assist in implementing Chapter 7.3 (commencing with Section 13560). SEC. 2. Section 13521 of the Water Code is amended to read: 13521. The State Department of Public Heal th shall establish uniform statewide recycling criteria for each varying type of use of recycled water where the use involves the protection of public health. SEC. 3. Chapter 7.3 (commencing with Section 13560) is added to Division 7 of the Water Code, to read:   81 CHAPTER 7.3. DIRECT AND INDIRECT POTABLE REUSE 13560. The Legislature finds and declares the following: (a) In February 2009, the state board unanimously adopted, as Resolution No. 2009-0011, an updated water recycling policy, which includes the goal of increasing the use of recycled water in the state over 2002 levels by at least 1,000,000 acre-feet per year by 2020 and by at least 2,000,000 acre-feet per year by 2030. (b) Section 13521 requires the department to establish uniform statewide recycling criteria for each varying type of use of recycled water where the use involves the protection of public health. (c) The use of recycled water for indirect potable reuse is critical to achieving the state board’s goals for increased use of recycled water in the state. If direct potable reuse can be demonstrated to be safe and feasible, implementing direct potable reuse would further aid in achieving the state board’s recycling goals. (d) Although there has been much scientific research on public health issues associated with indirect potable reuse through groundwater recharge, there are a number of significant unanswered questions regarding indirect potable reuse through surface water augmentation and direct potable reuse. (e) Achievement of the state’s goals depends on the timely development of uniform statewide recycling criteria for indirect and direct potable water reuse. (f) This chapter is not intended to delay, invalidate, or reverse any study or project, or development of regulations by the departmen t, the state board, or the regional boards regarding the use of recycled water for indirect potable reuse for groundwater recharge, surface water augmentation, or direct potable reuse. (g) This chapter shall not be construed to delay, invalidate, or reverse the department’s ongoing review of projects consistent with Section 116551 of the Health and Safety Code. 13561. For purposes of this chapter, the foll owing terms have the following meanings: (a) “Department” means the State Department of Public Health. (b) “Direct potable reuse” means the planned introduction of recycled water either directly into a public water system, as defined in Section 116275 of the Health and Safety Code, or into a raw water supply immediately upstream of a water treatment plant. (c) “Indirect potable reuse for groundwater recharge” means the planned use of recycled water for replenishment of a groundwater basin or an aquifer that has been designated as a source of water supply for a public water system, as defined in Section 116275 of the Health and Safety Code. (d) “Surface water augmentation” means the planned placement of recycled water into a surface water reservoir used as a source of domestic drinking water supply. (e) “Uniform water recycling criteria” has the same meaning as in Section 13521. 13561.5. The state board shall enter into an agreement with the department to assist in implementing this chapter. 13562. (a) (1) On or before December 31, 2013, the department shall adopt uniform water recycling criteria for indirect potable reuse for groundwater recharge. (2) (A) Except as provided in subparagraph (C), on or before December 31, 2016, the   82 department shall develop and adopt uniform water recycling criteria for surface water augmentation. (B) Prior to adopting uniform water recycling criteria for surface water augmentation, the department shall submit the proposed criteria to the expert panel convened pursuant to subdivision (a) of Section 13565. The expert panel shall review the proposed criteria and shall adopt a finding as to whether, in its expert opinion, the proposed criteria would adequately protect public health. (C) The department shall not adopt uniform water recycling criteria for surface water augmentation pursuant to subparagraph (A), unless and until the expert panel adopts a finding that the proposed criteria would adequately protect public health. (b) Adoption of uniform water recycling criteria by the department is subject to the requirements of Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code. 13563. (a) (1) The department shall investigate and report to the Legislature on the feasibility of developing uniform water recycling criteria for direct potable reuse. (2) The department shall complete a public review draft of its report by June 30, 2016. The department shall provide the public not less than 45 days to review and comment on the public review draft. (3) The department shall provide a final report to the Legislature by December 31, 2016. The department shall make the final report available to the public. (b) In conducting the investigation pursuant to subdivision (a), the department shall examine all of the following: (1) The availability and reliability of recycled water treatment technologies necessary to ensure the protection of public health. (2) Multiple barriers and sequential treatment processes that may be appropriate at wastewater and water treatment facilities. (3) Available information on health effects. (4) Mechanisms that should be employed to protect public health if problems are found in recycled water that is being served to the public as a potable water supply, including, but not limited to, the failure of treatment systems at the recycled water treatment facility. (5) Monitoring needed to ensure protection of public health, including, but not limited to, the identification of appropriate indicator and surrogate constituents. (6) Any other scientific or technical issues that may be necessary, including, but not limited to, the need for additional research. (c) (1) Notwithstanding Section 10231.5 of the Government Code, the requirement for submitting a report imposed under paragraph (3) of subdivision (a) is inoperative on December 31, 2020. (2) A report to be submitted pursuant to paragraph (3) of subdivision (a) shall be submitted in compliance with Section 9795 of the Government Code. 13563.5. (a) The department, in consultation with the state board, shall report to the Legislature as part of the annual budget process, in each year from 2011 to 2016, inclusive, on the progress towards developing and adopting uniform water recycling   83 criteria for surface water augmentation and its investigation of the feasibility of developing uniform water recycling criteria for direct potable reuse. (b) (1) A written report submitted pursuant to subdivision (a) shall be submitted in compliance with Section 9795 of the Government Code. (2) Pursuant to Section 10231.5 of the Government Code, this section is repealed on January 1, 2017. 13564. In developing uniform recycling criteria for surface water augmentation, the department shall consider all of the following: (a) The final report from the National Water Research Institute Independent Advisory Panel for the City of San Diego Indirect Potable Reuse/Reservoir Augmentation (IPR/RA) Demonstration Project. (b) Monitoring results of research and studies regarding surface water augmentation. (c) Results of demonstration studies conducted for purposes of approval of projects using surface water augmentation. (d) Epidemiological studies and risk assessments associated with projects using surface water augmentation. (e) Applicability of the advanced treatment technologies required for recycled water projects, including, but not limited to, indirect potable reuse for groundwater recharge projects. (f) Water quality, limnology, and health risk assessments associated with existing potable water supplies subject to discharges from municipal wastewater, stormwater, and agricultural runoff. (g) Recommendations of the State of California Constituents of Emerging Concern Recycled Water Policy Science Advisory Panel. (h) State funded research pursuant to Section 79144 and subdivision (b) of Section 79145. (i) Research and recommendations from the United States Environmental Protection Agency Guidelines for Water Reuse. (j) Other relevant research and studies regarding indirect potable reuse of recycled water. 13565. (a) (1) The department shall convene and administer an expert panel for the purposes of advising the department on public health issues and scientific and technical matters regarding development of uniform water recycling criteria for indirect potable reuse through surface water augmentation and investigation of the feasibility of developing uniform water recycling criteria for direct potable reuse. (2) The expert panel shall be comprised, at a minimum, of a toxicologist, an engineer licensed in the state with at least three years’ experience in wastewater treatment, an engineer licensed in the state with at least three years’ experience in treatment of drinking water supplies and knowledge of drinking water standards, an epidemiologist, a microbiologist, and a chemist. (3) Members of the expert panel may be reimbursed for reasonable and necessary travel expenses. (b) (1) The department may appoint an advisory group, task force, or other group, comprised of no fewer than nine representatives of water and wastewater agencies, local public health officers, environmental organizations, environmental justice organizations,   84 public health nongovernmental organizations, and the business community, to advise the department regarding the development of uniform water recycling criteria for direct potable reuse. (2) Environmental, environmental justice, and public health nongovernmental organization representative members of the advisory group, task force, or other group may be reimbursed for reasonable and necessary travel expenses. 13566. In performing its investigation of the feasibility of developing the uniform water recycling criteria for direct potable reuse, the department shall consider all of the following: (a) Recommendations from the expert panel appointed pursuant to subdivision (a) of Section 13565. (b) Recommendations from an advisory group, task force, or other group appointed by the department pursuant to subdivision (b) of Section 13565. (c) Regulations and guidelines for these activi ties from jurisdictions in other states, the federal government, or other countries. (d) Research by the state board regarding unregulated pollutants, as developed pursuant to Section 10 of the recycled water policy adopted by state board Resolution No. 2009-0011. (e) Results of investigations pursuant to Section 13563. (f) Water quality and health risk assessments associated with existing potable water supplies subject to discharges from municipal wastewater, stormwater, and agricultural runoff. 13567. An action authorized pursuant to this chapter shall be consistent, to the extent applicable, with the federal Clean Water Act (33 U.S.C. Sec. 1251 et seq.), the federal Safe Drinking Water Act (42 U.S.C. Sec. 300f et seq.), this division, and the California Safe Drinking Water Act (Chapter 4 (commencing with Section 116270) of Part 12 of Division 104 of the Health and Safety Code). 13569. The department may accept funds from any source, and may expend these funds, upon appropriation by the Legislature, for the purposes of this chapter.                                                                             Appendix B Texas Commission of Environmental Quality Letter to Big Springs, Texas 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 CALIFORNIA