Distribution System Water Quality Strategic Initiative Expert Workshop Report

Transcription

1 Distribution System Water Quality Strategic Initiative Expert Workshop Report Project #4125 Subject Area: High-Quality Water October 5, 2007

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3 AwwaRF PROJECT 4125 DISTRIBUTION SYSTEM WATER QUALITY STRATEGIC INITIATIVE EXPERT WORKSHOP REPORT Prepared by: Yakir J. Hasit, Steve Reiber, and Anthony Parolari CH2M HILL, INC Sponsored by: Awwa Research Foundation 6666 West Quincy Avenue, Denver, CO FINAL 5 October 2007

4 CONTENTS LIST OF TABLES... iii EXECUTIVE SUMMARY... iv STRATEGIC INITIATIVE OBJECTIVES... 1 PROJECT OBJECTIVES AND SCOPE DEVELOPMENT OF WHITE PAPER EXPERT WORKSHOP DEVELOPMENT OF INITIATIVE PROJECTS RECOMMENDED PROJECTS AND IMPLEMENTATION SCHEDULE APPENDIX A WHITE PAPER APPENDIX B RECOMMENDED PROJECT DESCRIPTIONS WORKSHOP REPORT ii OCTOBER 5, 2007

5 LIST OF TABLES 1 Project Idea Rankings Based on Workshop Attendees Votes (HR= Health Risk, CS= Customer Service, REG = Regulatory, O&M= Operations and Maintenance) Objectives of the Top-Ranked Projects as Defined in the Expert Workshop (Note: Project 5 incorporates Project 8, Project 8 incorporates Project 16) Potential Follow on Projects for Top-Ranked Projects (Follow-on top ranked projects are shown with an *) Top-Ranked Projects from the Expert Workshop with Theme Areas Identified Preliminary Implementation Schedule for High-Priority Projects WORKSHOP REPORT iii OCTOBER 5, 2007

6 EXECUTIVE SUMMARY Awwa Research Foundation (AwwaRF) has undertaken the Distribution System Water Quality Strategic Initiative (SI) to enhance its efforts in developing phased research projects that will not be preempted by annual or short term project budget priorities in other research areas. The objective of this 5-year SI is to develop integrated projects focused on water quality degradation due to transformations that take place within the distribution system, including premise plumbing. This workshop report, which prepares important input for this SI, was developed through the execution of the following three tasks: 1. Development of a white paper to summarizing the state of science and research needs 2. Getting input and research ideas from water industry experts though an Expert Workshop 3. Development of preliminary projects for funding by the SI. The project ideas (including their objectives) that were recommended by the workshop participants were ranked, and the top-ranked projects were further expanded by developing project descriptions and preliminary funding levels. To be strategic in nature, these projects had to meet the following criteria: Criticality to the water community of the data gaps identified in the project, Complexity and multidisciplinary character of the identified problem hence, requiring a collaborative effort going beyond the capability of a single utility, Relevance to a strategic vision of how utilities will be managed, operated, maintained and sustained into the future. The top-ranked projects in this research plan primarily cover biofilms/pathogens, disinfection/dbps, corrosion/leaching and premise plumbing. WORKSHOP REPORT iv OCTOBER 5, 2007

7 STRATEGIC INITIATIVE OBJECTIVES Significant water quality changes that occur within water distribution systems have received increased attention as these changes sometimes negate the treatment taking place at water treatment plants. These changes make it harder for utilities to meet increased levels of service and regulatory requirements. Due to the complexity of the fate, transport and transformation of contaminants, and their subsequent accumulation and release within the distribution system, the drinking water community has been allocating significant resources to investigate the chemical, physical, and microbial mechanisms that cause water quality changes. Recent research activities have focused on characterizing these processes and their impacts on water quality. The USEPA, with the support of water utility, academic and consulting experts, has published distribution system and Total Coliform Rule (TCR) white papers and issue papers to provide guidance in shaping future distribution system regulations. Awwa Research Foundation (AwwaRF) has traditionally funded significant research on distribution system water quality. With the Distribution System Water Quality Strategic Initiative, AwwaRF is now enhancing its efforts to develop phased research projects over a 5 year period that will not be preempted by annual or short term project budget priorities in other research areas. The objective of this 5-year Strategic Initiative (SI) is primarily to develop integrated projects focused on water quality degradation due to transformations that take place within the distribution system (pipes, tanks, plumbing, etc.). Water quality changes also take place due to the loss in physical integrity (such as contaminant intrusion due to breaks or faulty repairs) and hydraulic integrity of pipes (such as contaminant intrusion due to low or negative pressures). Although such changes are not directly addressed in this initiative, any overlapping water quality issues among them are considered relevant. There will be a number of differences between the projects initiated under the SI and standard AwwaRF projects. First, the projects funded under this SI must all relate to the goals defined for the SI while advancing the science of water, which is the standard goal applied to all AwwaRF projects. Second, these projects goals must meet the SI s goals and be clearly stated, defined, and their progress must be measurable. Finally, these projects will be identified by an Expert Panel, which members are stewards of the initiative and will assist AwwaRF in continuity and focus of the SI. This expert panel will incorporate advances in knowledge from AwwaRF and other research activities as well as industry needs, as they select new projects to begin each year. PROJECT OBJECTIVES AND SCOPE AwwaRF contracted CH2M HILL in March 2007 to facilitate and document an expert workshop which would provide input into the research planning for this SI. AwwaRF then formed an Expert Panel to provide guidance and oversight for the projects to be WORKSHOP REPORT 1 OCTOBER 5, 2007

8 developed under this initiative. The members of this Expert Panel are from water utilities, consulting firms and academia and are listed below: Gary Burlingame Philadelphia Water Department Ann Camper, PhD Montana State University Gregory Kirmeyer, PE - HDR Mark LeChevallier, PhD American Water Pankaj Parekh Los Angeles Department of Water and Power Charlotte Smith Charlotte Smith and Associates, Inc. This workshop report was developed through the execution of the following three tasks: 1. DEVELOPMENT OF WHITE PAPER A White Paper (see Appendix A) was prepared to provide background information on the state of science both for the Expert Workshop (Task 2, below) and for establishing preliminary research needs. The primary, but not exclusive, resource for the development of the White Paper was "Chapter 6 - Water Quality Integrity" in Drinking Water Distribution Systems: Assessing and Reducing Risks (2006) by the Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks (Committee) of the National Research Council (NRC). This chapter, along with Chapters 4 and 5, address distribution system water quality, as well as physical and hydraulic integrity of the distribution system, respectively. Each of these chapters is divided into the following five sections: Factors causing lack of integrity Consequences of lack of integrity Detecting lack of integrity Maintaining integrity Recovering integrity This breakdown was used in structuring the White Paper. The NRC document incorporates the findings of most distribution system water quality research (both academic and other), AwwaRF reports, and guidance documents. In this White Paper, the NRC report was supplemented by information gathered from the USEPA s recent series of distribution system and TCR white papers and issue papers, additional AwwaRF studies, and other literature. The following areas of interdisciplinary research were recommended in the White Paper for consideration in the SI. 1. Fundamental Processes and Mechanisms. In general, the fundamental principles of internal chemical and biological processes need to be further characterized. These include biofilm growth, disinfectant decay, DBP formation and decay, and WORKSHOP REPORT 2 OCTOBER 5, 2007

9 internal corrosion. Ultimately, the ability to describe these processes will allow models to be applied universally, improving the identification of contamination events and the efficiency of the decision-making process. These models may also be incorporated with current hydraulic models, providing a tool capable of predicting likely contamination sources and the system areas affected by internal water quality deterioration or external contamination. 2. Health Risk Assessment. Assessing the public health risk of distribution system contamination is a difficult task as limited data is available to link water quality changes to increased incidence of certain health problems, especially in sensitive population subsets. Additional data to characterize the spatial and temporal dynamics of contamination events are needed to evaluate current exposure assessment and regulatory approaches. Epidemiological studies will identify exposure pathways and quantify the risk of certain contamination events. Further study into the physiological effects of distribution system contaminants will identify public health issues and susceptible populations. 3. Monitoring Capabilities. Field analytical capabilities are in need of improvement to provide quick, inexpensive analysis to support operations decisions. On-line and real-time monitoring allow utilities to constantly monitor conditions in the distribution system and react quickly to adverse conditions that may impact public health. The monitoring capabilities should be extended to analyses related to DBP concentrations and indicators of nitrification, corrosion, and microbial activity. Continuously collected data can support real-time water quality and hydraulic modeling and provide the basis for a comprehensive utility decisionsupport system. 4. Materials. The materials used in distribution system construction and maintenance have a significant impact on water quality, contributing to contamination through corrosion and leaching. Research is needed to improve understanding of the processes causing these conditions and to develop new materials that are not prone to these types of events. Utilities will benefit from this research as new material standards are developed to address water quality changes as well as structural integrity. 5. Water Quality Maintenance and Recovery. Utilities use various practices such as booster disinfection, flushing, corrosion control, etc to maintain the water quality integrity within their distribution systems and in premise plumbing. It is important to develop performance measures to quantify the effectiveness of these practices. These research areas will lead to the detailed knowledge of internal processes and continuous monitoring capabilities, enabling utilities to begin to integrate data collection, risk assessment, and management activities. Recent research has focused on this integration through developments in hydraulic and water quality models, data WORKSHOP REPORT 3 OCTOBER 5, 2007

10 storage and management, and decision-support systems. These tools will provide the future utility with seamless access to water quality data, predictions of contamination events and susceptible regions, and potential for remedial strategies. 2. EXPERT WORKSHOP On May 30-31, 2007 an Expert Workshop was held at CH2M HILL s Headquarters (Englewood, CO) to get input from water industry experts on the development of suggested research projects for this initiative. The workshop attendees included water utility, consulting, university, USEPA and AwwaRF staff. To develop project ideas, the attendees joined the following breakout groups which were formed based on key utility drivers: Customer service issues Operations and maintenance (O&M) issues Regulatory issues Health risk issues The breakout groups were tasked to develop projects that would have the following features: Criticality to the water community of the data gaps identified in the project, Complexity and multidisciplinary character of the identified problem hence, requiring a collaborative effort going beyond the capability of a single utility, Relevance to a strategic vision of how utilities will be managed, operated, maintained and sustained into the future (10-15 years). Based on this guidance, workshop participants developed 38 project ideas along with their objectives. Partial descriptions of the projects were presented to the group as a whole. These ideas then were ranked by the participants based on the features listed above, and preliminary project descriptions were developed for the higher ranked projects. Project rankings are presented in Table 1 below, while the top-ranked 14 projects objectives are presented in Table 2. After the rankings, some project ideas were merged by the workshop participants (Project 5 with 8, and 12 with 16) resulting in a total of 36 project ideas. Based on the anticipated budget for the SI ($1M/year over 5 years), 14 top-ranked projects were selected for further development. These 14 projects received the top seven votes, including ties. Additional information on the workshop can be found in Appendix B which provides the agenda, list of attendees, and presentations by the Expert Panel. Project descriptions, which were revised after the workshop with input from workshop participants, AwwaRF staff, Expert Panel and the project team, can be found in Appendix C (discussed below). WORKSHOP REPORT 4 OCTOBER 5, 2007

11 Table 1 Project Idea Rankings Based on Voting by Workshop Attendees Votes (HR= Health Risk, CS= Customer Service, REG = Regulatory, O&M= Operations and Maintenance) RANK PROJ # GROUP TITLE VOTE 1 1 HR Role of Biofilm on the Fate and Transport of Waterborne Pathogens in Distribution System and Premise Plumbing HR Efficacy of Secondary Disinfection For Pathogen Control CS Lead and Copper Corrosion Control in New Construction O&M Formation, Activity and Significance of Organochloramines HR Microbial Ecology of Piped Water With Respect to Health Risks REG Evaluate Alternatives to the Total Coliform Indicators HR Characterizing the Components of the Microbial Community Responsible For Nitrification 5 8 HR Screening of Methods For Determining the Microbial Ecology of Distribution Systems 6 9 CS Water Industry Contribution to Epidemiological Studies Involving Distribution System Water Quality 6 10 O&M Effects of Disinfectants, Natural Organic Matter and Other Water Quality Parameters on the Internal Corrosion of Iron Pipe and Stability of Surface Scales 6 11 REG Development of Predictive Models for the Formation and Fate of DBPs in Distribution Systems 7 12 CS Occurrence Study of Water Quality Changes in Premise Plumbing 7 13 HR Developing Exposure Estimates of the Contribution on Drinking Water to Blood Lead Levels Using Realistic Integrated Water Levels 7 14 HR Identification of Research Gaps in Defining Biological Stability of Water in North American Distribution Systems 7 15 O&M Real-Time Data Fusion to Support Distribution System Operation and Management WORKSHOP REPORT 5 OCTOBER 5, 2007

12 RANK PROJ # GROUP TITLE VOTE 8 16 CS Constructing A Research Framework For Customer Plumbing Water Quality Issues 8 17 O&M Evaluation and Demonstration of Distributed Treatment Technologies 8 18 O&M Implementation of Robust and Efficient Online Water Quality Monitoring Systems O&M Early Detection and Control of Nitrification REG Influence of Distribution System Design and Operation on Virus Intrusion in Eight Municipal Systems in WI REG Cross Connection and Backflow Event Occurrence REG Evaluate the Statistical Sampling Strategies That Support Operations and Characterization 9 23 O&M Comprehensive Field Assessment of Distribution System Water Quality Changes From Entry to Tap 9 24 O&M Short and Long-Term Impacts of Water Quality Changes on Lead Release 9 25 REG Development of Material Specific Corrosion Scale Stability Indices 9 26 REG Protocol to Estimate Inorganic Contaminant Release From Distribution System Deposits HR Evaluation of the Efficacy of Biological Filtration and Membrane Treatment on Maintaining Water Quality in Distribution Systems REG Litigation Based on Legislation CS Iron and Manganese Sequestration By Poly-Phosphates, Silicates and Alternative Compounds HR Defining Operational Practices and Monitoring Strategies Leading to the Production and Maintenance of Biologically Stable Water O&M Chloramination Conversion and Optimization: A Practical Guide REG Re-Evaluating, Standardizing, Certifying Cross Connection Control Programs, Technologies & Practices WORKSHOP REPORT 6 OCTOBER 5, 2007

13 RANK PROJ # GROUP TITLE VOTE REG Economics of Water Loss Health and Non-Health Benefits HR The Influence of Biological Process in Lead Corrosion REG Quantitative Assessment of Biomass in the Distribution System REG Develop Workforce Plans to Support Future Distribution System Rules O&M Cost-Benefit Analysis of Dual Distribution Systems O&M Advanced Water Quality Modeling in Distribution Systems 0 Table 2 Objectives of the Top-Ranked Projects as Defined in the Expert Workshop (Note: Project 5 incorporates Project 8, Project 12 incorporates Project 16) PROJ # TITLE 1 Role of Biofilm on the Fate and Transport of Waterborne Pathogens in Distribution System and Premise Plumbing OBJECTIVES Increasing attention is being given to the role of biofilms in distribution systems and premise plumbing for the sequestering, growth /inactivation, and protection of both opportunistic and frank pathogens. The mechanisms by which these organisms are retained and released are poorly understood and will be described in this research. An outcome could be mass balances on pathogens across a system when considering the processes described above. 2 Efficacy of Secondary Disinfection For Pathogen Control 3 Lead and Copper Corrosion Control in New Construction To assess the net health benefit of maintaining a secondary disinfectant in potable distribution systems for pathogen control in biofilms. The objective of this research is to develop a guidance document for contractors, plumbers, and construction managers describing steps to minimize lead and copper corrosion problems in new construction. The project will establish procedures for properly flushing new building plumbing, including flushing times and velocities. The effects of in-building pipe disinfection on corrosion will also be investigated, leading to specific recommendations regarding this practice. WORKSHOP REPORT 7 OCTOBER 5, 2007

14 PROJ # TITLE OBJECTIVES 4 Formation, Activity and Significance of Organochloramines 5 Microbial Ecology of Piped Water With Respect to Health Risks (incorporates #8) 6 Evaluate Alternatives to the Total Coliform Indicators 7 Characterizing the Components of the Microbial Community Responsible For Nitrification 9 Water Industry Contribution to Epidemiological Studies Involving Distribution System Water Quality 10 Effects of Disinfectants, Natural Organic Matter and Other Water Quality Parameters on the Internal Corrosion of Iron Pipe and Stability of Surface Scales The objective of this research is to investigate the formation, activity, and significance of organochloramines in the distribution system. This project will attempt to establish formation conditions, chemical properties, concentrations, and reactivity of these compounds. The research will be based on a comprehensive understanding of the chemistry of haloamines, disinfection by-products formation associated with them, other related topics, and experimental exploration. Develop a broad-range ecological assessment of the microbiota within biofilms of distribution systems, in premises and within point of use devices, with the longterm goal of identifying healthy community structures, which may provide insight into periods of system compromise. This assessment will address temporal and spatial trends for a range of water types expected across the United States. As the total coliform rule is reconsidered there are significant concerns over the usefulness and meaning of using total coliform as an indicator of distribution system water quality. This project will evaluate current and emerging alternatives to total coliform as an indicator of the microbial conditions in distribution systems. The objective of this study is to identify the microorganisms in distribution systems and premise plumbing that are responsible for nitrification. There is a lack of understanding of the diversity of organisms that nitrify and their activities in finished water. Determining what organisms are involved will allow for better detection and quantification methods The objective of this research is to provide guidance, from the perspective of the water industry, to researchers conducting epidemiological studies involving drinking water in distribution systems. This study will generate experimental results to further understanding of the extent and implications of the effects of water quality on iron corrosion and surface scale stability. It is anticipated that these results will help water utilities and drinking water professionals better manage iron corrosion and scale dissolution in the distribution system. WORKSHOP REPORT 8 OCTOBER 5, 2007

15 PROJ # TITLE OBJECTIVES 11 Development of Predictive Models for the Formation and Fate of DBPs in Distribution Systems 12 Occurrence Study of Water Quality Changes in Premise Plumbing (incorporates #16) This project will encompass several objectives: Evaluate the formation of selected DBPs (focusing on DBPs having the highest potential health risks, including iodated and brominated compounds) Consider processes that form them and processes that may degrade them in the distribution system Assess the role of water phase and the pipe-water interface in contributing to the formation and loss of DBPs Characterize abiotic and biological roles Assess the influence of distribution system characteristics Compare this contribution to that occurring in the water phase Develop predictive models These objectives are intended to improve the understanding of processes forming and degrading selected important DBPs; determine the relative importance of in-plant and in-system formation; and to develop qualitative and quantitative models capable of predicting the influence of key water quality and distribution systems characteristics and the effect of various management strategies. The objective of this project is to characterize the types of water quality changes that occur in premise plumbing and to develop a research framework that provides a comprehensive examination of these water quality issues. Identification must include noting various components of the customer plumbing system, the materials employed, and the operation of the plumbing system that play a major role in water quality changes. The water quality changes of interest will be focused on those with potential for health risk concern and/or regulatory violation. The research framework will provide a needed structure for research related to water quality concerns within customer plumbing systems. This research may also provide an outline for a future comprehensive document that will enable water utility customers to make the most appropriate decisions to foster optimum water quality within the water lines that they control and maintain. WORKSHOP REPORT 9 OCTOBER 5, 2007

16 PROJ # TITLE OBJECTIVES 13 Developing Exposure Estimates of the Contribution on Drinking Water to Blood Lead Levels Using Realistic Integrated Water Levels 14 Identification of Research Gaps in Defining Biological Stability of Water in North American Distribution Systems 15 Real-Time Data Fusion to Support Distribution System Operation and Management The objective of this research is to develop monitoring strategies for lead in drinking water that can be used to assess lead exposure by individuals. These monitoring strategies will then be applied to a few systems to determine consumption profiles for various subgroups that can be used in conjunction with the EPA/CDC lead uptake model to develop estimates of the contribution of drinking water to blood levels for different subpopulations. The objective of this project is to perform a comprehensive review of research that has been completed abroad and in the United States on biological stability of water in distribution systems, with emphasis on the experiences gained in North American systems. This project will provide insight on what research still needs to be performed to provide US systems with the information they need to adequately design, implement, operate, and monitor water treatment plants to produce biologically stable water that would persist throughout the distribution system. Another component of this project will be to identify factors in the distribution system that support the growth of microorganisms and therefore contribute to the degradation of water quality. This study will use real-time data from multiple streams (e.g., real-time water quality sensors, real-time hydraulic models, pressure and flow sensors, customer complaints, and pump operation) to detect water quality events and identify their common causes. The resulting methodology should be useable in real-time to direct response activities, as well as in a retrospective mode to feed water quality information into asset management decisions. A key objective is to demonstrate the methodology in a field-scale pilot project, and to deliver the methodology as a software application that can be extended and incorporated as part of a SCADA system. 3. DEVELOPMENT OF INITIATIVE PROJECTS As mentioned above, following the Expert Workshop, additional input was received from workshop participants and the Expert Panel. Revisions were made to the recommended projects and some projects were consolidated. After the submittal of this project s draft report, further comments were received from some workshop participants. The Expert Panel, AwwaRF staff and the project team jointly revised the top 14 project descriptions and they are presented in Appendix C. Also a strawman for WORKSHOP REPORT 10 OCTOBER 5, 2007

17 the potential follow-on projects for the top-ranked projects has been provided in Table 3. In 2008, prior to the release of the Requests for Proposals (RFPs) the finalization of the projects and funding priorities will be made by the Expert Panel. This will be based not only on input received to date, but also other information that might not have been available at the workshop. A key consideration will be the goals established for this Strategic Initiative. Table 3 Potential Follow-on Projects for Top-Ranked Projects (Follow-on top-ranked projects are shown with an *) Top-Ranked Project Role of Biofilm on the Fate and Transport of Waterborne Pathogens in Distribution System and Premise Plumbing Efficacy of Secondary Disinfection For Pathogen Control Lead and Copper Corrosion Control in New Construction Potential Follow-On Projects Quantitative Assessment of Biomass in the Distribution System Chloramination Conversion and Optimization: A Practical Guide Evaluation and Demonstration of Distributed Treatment Technologies Evaluation of the Efficacy of Biological Filtration and Membrane Treatment on Maintaining Water Quality in Distribution Systems Formation, Activity and Significance of Organohaloamines* (formerly Formation, Activity and Significance of Organochloramines) Short and Long-Term Impacts of Water Quality Changes on Lead Release The Influence of Biological Process in Lead Corrosion Developing Exposure Estimates of the Contribution on Drinking Water to Blood Lead Levels Using Realistic Integrated Water Levels* Development of Predictive Models for the Formation and Fate of Regulatory DBPs in Distribution Systems (formerly Development of Predictive Models for the Formation and Fate of DBPs in Distribution Systems) Microbial Ecology of Piped Water With Respect to Health Risks Influence of Distribution System Design and Operation on Virus Intrusion in Eight Municipal Systems in WI WORKSHOP REPORT 11 OCTOBER 5, 2007

18 Top-Ranked Project Development Of Multiple Indicators Of Distribution System Microbial Integrity (formerly Evaluate Alternatives to the Total Coliform Indicators) Characterizing the Components of the Microbial Community Responsible For Nitrification Potential Follow-On Projects Early Detection and Control of Nitrification Water Industry Contribution to Epidemiological Studies Involving Distribution System Water Quality Effects of Disinfectants, Natural Organic Matter and Other Water Quality Parameters on the Internal Corrosion of Iron Pipe and Stability of Surface Scales Occurrence Study of Water Quality Changes in Premise Plumbing Development of Material Specific Corrosion Scale Stability Indices Protocol to Estimate Inorganic Contaminant Release From Distribution System Deposits Iron and Manganese Sequestration By Poly- Phosphates, Silicates, and Alternative Compounds Cross Connection and Backflow Occurrence Re-Evaluating, Standardizing, and Certifying Cross Connection Control Programs, Technologies, and Practices Identification of Research Gaps in Defining Biological Stability of Water in North American Distribution Systems Defining Operational Practices and Monitoring Strategies Leading to the Production and Maintenance of Biologically Stable Water Real-Time Data Fusion to Support Distribution System Operation and Management Evaluate the Statistical Sampling Strategies That Support Operations and Characterization Implementation of Robust and Efficient Online Water Quality Monitoring Systems Advanced Water Quality Modeling in Distribution Systems Other Comprehensive Field Assessment of Distribution System Water Quality Changes From Entry to Tap Litigation Based on Legislation Economics of Water Loss Health and Non- Health Benefits Cost-Benefit Analysis of Dual Distribution Systems WORKSHOP REPORT 12 OCTOBER 5, 2007

19 RECOMMENDED PROJECTS AND IMPLEMENTATION SCHEDULE The results of the ranking show a focus on the following themes: Biofilms/pathogens Disinfection/DBPs Corrosion/leaching Premise plumbing Table 4 identifies the top-ranked recommended projects by these themes. Projects that do not fall under these categories are identified as other. All these projects met the data gap criticality and complexity and multidisciplinary character features criteria. While the most difficult to quantify, the third feature, i.e. the relevance to a strategic vision for the future distribution systems was considered by the workshop organizers to be the most crucial. As presented above in Task 1, one version of this strategic vision was put forward in the White Paper (Appendix A) emphasizing the development of predictive models, new monitoring techniques, improved remedial strategies, and materials specification for the distribution systems of the future. Table 4 Top-Ranked Projects from the Expert Workshop with Theme Areas Identified PROJ GROUP TITLE # 1 Biofilms/pathogens Role of Biofilm on the Fate and Transport of Waterborne Pathogens in Distribution System and Premise Plumbing 2 Biofilms/pathogens Efficacy of Secondary Disinfection For Pathogen Control Disinfection/DBPs 3 Corrosion/leaching Lead and Copper Corrosion Control in New Construction Premise plumbing 4 Disinfection/DBPs Formation, Activity and Significance of Organohaloamines 5 Biofilms/pathogens Microbial Ecology of Piped Water With Respect to Health Risks Premise plumbing 6 Biofilms/pathogens Development Of Multiple Indicators Of Distribution System Microbial Integrity 7 Biofilms/pathogens Characterizing the Components of the Microbial Community Responsible For Nitrification 9 Other Water Industry Contribution to Epidemiological Studies Involving Distribution System Water Quality 10 Disinfection/DBPs Corrosion/leaching Premise plumbing Effects of Disinfectants, Natural Organic Matter and Other Water Quality Parameters on the Internal Corrosion of Iron Pipe and Stability of Surface Scales 11 Disinfection/DBPs Development of Predictive Models for the Formation and Fate of Regulatory DBPs in Distribution Systems WORKSHOP REPORT 13 OCTOBER 5, 2007

20 PROJ GROUP TITLE # 12 Premise plumbing Occurrence Study of Water Quality Changes in Premise Plumbing 13 Corrosion/leaching Premise plumbing Developing Exposure Estimates of the Contribution on Drinking Water to Blood Lead Levels Using Realistic Integrated Water Levels 14 Biofilms/pathogens Identification of Research Gaps in Defining Biological Stability of Water in North American Distribution Systems 15 Other Real-Time Data Fusion to Support Distribution System Operation and Management While all of the projects would serve to shape the future distribution system, several of the highly ranked projects are clearly directed at the concept of a strategic vision for the future distribution system. These include: Development of Multiple Indicators of Distribution System Microbial Integrity (Ranked: 4) - The utility of the Coliform Rule is suspect and under consideration, this project would evaluate emerging alternatives to total coliform as a microbial indicator of the pathogen ecology in distribution systems. Development of Predictive Models for the Formation and Fate of Regulatory DBPs in Distribution Systems (Ranked: 6) This project would characterize abiotic and biological roles in the formation of selected DBPs (focusing on DBPs having the highest potential health risks, including suspect iodoform and bromoform compounds) and assessing the role of water phase and pipe water interface, leading to model that can play a operations role in minimizing DBP exposure when dealing with multiple source waters. Real-time Data Fusion to Support Distribution System Operation and Management (Ranked: 7) This project would use real-time data from multiple streams (e.g., real-time water quality sensors, real-time hydraulic models, pressure and flow sensors, customer complaints, and pump operation) to detect water quality events and identify their causes. This project would also deliver the methodology as a software application that can be extended and incorporated as part of a SCADA system. Among the projects that were not in the top 14, several projects also addressed strategic vision concepts, including: Evaluation and Demonstration of Distributed Treatment Technologies This project focused on a potential future that emphasizes small household and community treatment systems (water and wastewater) minimizing energy requirements and promoting sustainability. Implementation of Robust and Efficient Online Water Quality Monitoring Systems This project focused on security and future water quality challenges. WORKSHOP REPORT 14 OCTOBER 5, 2007

21 Litigation Based on Legislation This project would provide guidance for future regulations with intent to partially immunize the utilities in response to growing civil litigations. Defining Operational Practices and Monitoring Strategies Leading to the Production and Maintenance of Biologically Stable Water This project recognizes the growing importance of bio-stability as an effective operations and management tool. While important, these projects were clearly not considered as high a priority as filling some persistent data gaps in our understanding of distribution system microbial ecology, corrosion, and DBP formation. The bulk of the 14 top-ranked projects address these important issues because it was felt that until these gaps are filled, specific public health issues cannot be effectively resolved, and pending regulatory issues moved forward. As a starting point, a preliminary project implementation schedule has been developed for review and presented in Table 5. In developing this schedule the ranks, preliminary funding levels and logical sequence were taken into account. This implementation schedule will be finalized by the Expert Panel and AwwaRF staff prior to the release of the RFPs. Table 5 Preliminary Implementation Schedule for High-Priority Projects Recommended Year and Budget ($1,000) RANK TITLE Role of Biofilm on the Fate and Transport of Waterborne Pathogens in Distribution System and Premise Plumbing 2 Efficacy of Secondary Disinfection For Pathogen Control 6 Water Industry Contribution to Epidemiological Studies Involving Distribution System Water Quality 3 Lead and Copper Corrosion Control in New Construction 4 Microbial Ecology of Piped Water With Respect to Health Risks 4 Development Of Multiple Indicators Of Distribution System Microbial Integrity (formerly Evaluate Alternatives to the Total Coliform Indicators) $600 $300 $120 $450 $600 $400 WORKSHOP REPORT 15 OCTOBER 5, 2007

22 Recommended Year and Budget ($1,000) RANK TITLE Characterizing the Components of the Microbial Community Responsible For Nitrification 3 Formation, Activity and Significance of Organohaloamines (formerly Formation, Activity and Significance of Organochloramines) 6 Effects of Disinfectants, Natural Organic Matter and Other Water Quality Parameters on the Internal Corrosion of Iron Pipe and Stability of Surface Scales 6 Development of Predictive Models for the Formation and Fate of Regulatory DBPs in Distribution Systems (formerly Development of Predictive Models for the Formation and Fate of DBPs in Distribution Systems) 7 Identification of Research Gaps in Defining Biological Stability of Water in North American Distribution Systems 7 Occurrence Study of Water Quality Changes in Premise Plumbing 7 Developing Exposure Estimates of the Contribution on Drinking Water to Blood Lead Levels Using Realistic Integrated Water Levels 7 Real-Time Data Fusion to Support Distribution System Operation and Management $250 $350 $500 $400 $200 $450 $250 $450 Total Annual Budget $1,020 $1050 $1000 $1100 $1,150 WORKSHOP REPORT 16 OCTOBER 5, 2007

23 APPENDIX A WHITE PAPER WORKSHOP REPORT 17 OCTOBER 5, 2007

24 AWWARF PROJECT 4125 DISTRIBUTION SYSTEM WATER QUALITY STRATEGIC INITIATIVE EXPERT WORKSHOP REPORT WHITE PAPER PREPARED FOR: Awwa RESEARCH FOUNDATION PREPARED BY: Anthony Parolari Steve Reiber, PhD Yakir Hasit, PhD, PE CH2M HILL, INC. FINAL 5 October 2007 FINAL WHITE PAPER 18 OCTOBER 5, 2007

25 INTRODUCTION The fate, transport and transformation of contaminants, and their subsequent accumulation and release within the distribution system are complex processes controlled by a number of chemical, physical, and microbial mechanisms. Recent research activities have focused on characterizing these processes and their impacts on water quality. Awwa Research Foundation s (AwwaRF s) Distribution System Water Quality Strategic Initiative is part of this effort to better understand water quality changes in the distribution system and to develop new strategies to maintain water quality between treatment plants and customers taps. This Distribution System Water Quality Strategic Initiative Expert Workshop Report project has been undertaken to support this Strategic Initiative (SI). The objective of this 5-year SI is primarily to develop integrated projects focused on water quality degradation due to transformations that take place within the distribution system (pipes, tanks, plumbing, etc.). Water quality changes also take place due to the loss in physical integrity (such as contaminant intrusion due to breaks or faulty repairs) and hydraulic integrity of pipes (such as contaminant intrusion due to low or negative pressures). Although such changes are not directly addressed in this initiative, any overlapping water quality issues among them are considered relevant. The three primary tasks of this SI Expert Workshop project are: 1. Develop a white paper to provide background on the state of science as a prelude for the Expert Workshop; 2. Organize an Expert Workshop and document the recommendations to support the development of a draft research plan for this initiative; and 3. Identify, develop, and prioritize a series of research project descriptions which will be used as the basis for the Research Foundation s 5-year research plan on this topic. The research projects developed in this SI will have the following key features: As there are many data gaps related to distribution system water quality, the data gaps to be identified and addressed in projects developed under this initiative should be of critical nature to the water community; The projects will be complex or multidisciplinary enough that they cannot be undertaken by a single water utility, and thus will usually require collaborative efforts; and The research projects will be forward-looking and relevant to our vision of how utilities will be managed, operated, and maintained in the future. Therefore, these projects will focus on the future and sustainability To facilitate the development of the project ideas, key utility drivers were used to categorize Expert Workshop breakout groups and associated projects. These were: Customer service issues FINAL WHITE PAPER 19 OCTOBER 5, 2007

26 Operations and Maintenance (O&M) issues Regulatory issues Health risk issues Topics covered under each area were elaborated in the Expert Workshop. Background To serve as a foundation for discussions at the Expert Workshop, this white paper provided a summary review on the state of science relative to distribution system water quality, as well as a starting point for the research needed to address gaps in this knowledge. The primary, but not exclusive, background resource for the development of this white paper was "Chapter 6 - Water Quality Integrity" in Drinking Water Distribution Systems: Assessing and Reducing Risks (2006) by the Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks (Committee) of the National Research Council (NRC). This chapter, along with Chapters 4 and 5, address the distribution system water quality, physical and hydraulic integrity, respectively. Each of these chapters is divided into five sections: 1) factors causing lack of integrity, 2) consequences of lack of integrity, 3) detecting lack of integrity, 4) maintaining integrity and 5) recovering integrity. This breakdown framed the issues well and was used in structuring this white paper. The NRC document (hereby referred to as the Committee Report) incorporates the findings of most distribution system water quality research (both academic and other), AwwaRF reports, and guidance documents. In this white paper, the Committee Report was supplemented by information gathered from the USEPA s recent series of distribution system white papers and Total Coliform Rule (TCR) issue papers, additional AwwaRF studies, and other literature. A Strategic Vision Distribution system water quality is affected by several internal processes whose consequences may impact customer service, O&M, regulatory compliance, and customer health. Microbial occurrence, disinfection, nitrification, corrosion, and disinfection by-product (DBP) formation are of primary interest to utilities and regulators. Many of these processes also occur in premise plumbing joining utility distribution systems and customers taps. In some cases, premise plumbing conditions may promote more serious consequences than found in the distribution system. Although premise plumbing are not owned by water utilities, under certain circumstances utilities can be held accountable for the water quality found at the tap. Thus, a strategic research effort is needed to define the mechanisms by which water quality degrades in distribution systems anywhere from the treatment plant to the tap, and the interaction of these mechanisms. An understanding of the principles driving water quality degradation may allow the development of predictive models, new monitoring techniques, improved remedial strategies, and materials specification for the distribution systems of the future. FINAL WHITE PAPER 20 OCTOBER 5, 2007

27 To date, distribution system water quality has been monitored to a relatively limited extent, as finished water parameters (at the plant effluent or entry to the distribution system) have traditionally been used as surrogate indicators of water safety. Existing regulations that require sampling in the distribution system include the TCR, Disinfectant / Disinfection Byproducts Rule, and Lead and Copper Rule (LCR). However, constituents monitored to achieve compliance with these rules, or others, may not be indicative of overall operational performance or total public health risk. Moreover, current sampling requirements are generally insufficient to capture shortterm contamination events, such as would be associated with security or crossconnection/backflow events. Analyses conducted to date of some limited numbers of real-time data streams indicate that water quality variations in the distribution system can be significant. Research is needed to broaden the suite of detectable chemical and biological constituents and to improve on-line, real-time data acquisition devices, along with real-time data analysis. With detailed knowledge of internal processes and continuous monitoring capabilities, utilities can begin to integrate data collection, risk assessment, and management activities. Recent research has focused on this integration through developments in hydraulic and water quality models, data storage and management, and decisionsupport systems. These tools will provide the future utility with seamless access to water quality data, predictions of contamination events and susceptible regions, and potential for remedial strategies. INTERNAL CAUSES OF WATER QUALITY DEGRADATION AND THEIR CONSEQUENCES Water quality within the distribution system may be negatively affected as a result of various chemical and biological processes that occur at the interface of the pipe wall or in the bulk fluid. These processes are often driven by the composition of drinking water (e.g. natural organic matter (NOM), temperature, ph) and by conditions in the distribution system, such as pipe materials, presence of microorganisms, or flow regimes. The current knowledge on these internal causes of water quality degradation, described in the Committee Report and other literature including a set of distribution system white papers, TCR issue papers, and AwwaRF studies, are summarized below. Research topics listed in Table 1 are recommended as a starting point to resolve gaps in this body of knowledge and to provide a basis for future distribution system design and maintenance practices and enhance customer service. FINAL WHITE PAPER 21 OCTOBER 5, 2007

28 Biofilms, Regrowth and Other Biological Contamination The biological stability of a distribution system is a function of many factors, including the accumulation of attached biomass (biofilms), regrowth of suspended organisms, water treatment plant effluent quality, and external sources of contamination. The NRC report states that biologically stable drinking water is one that does not support microbial growth in the distribution system, that is, nutrients (e.g. carbon, phosphorus) are at sufficiently low levels and there is adequate disinfectant residual. Water treatment processes are important in limiting microbial growth in the distribution system, by producing water that is biologically stable. Nevertheless, microbial activity is still common in distribution systems and is related to processes discussed further below. Given the nature of microbial behavior, biofilms are inevitable in all distribution systems regardless of water quality characteristics and pipe materials. Biofilm growth is governed by the complex interactions of several physical and chemical processes, and the mechanisms leading to biofilm growth are often system-specific. Biofilms can support the growth of pathogens and coliforms, which may be subsequently released into the distribution system. In addition to biological contamination, biofilms may also contribute to other losses of distribution system integrity, including corrosion of copper or iron pipe, nitrification in chloraminated systems, taste and odor issues, reduced hydraulic capacity, and increased chlorine demand. Taste and odor problems and reduced hydraulic capacity do not necessarily pose a public health risk, but can impact customer satisfaction and system operation. Coliform bacteria and other suspended heterotrophs can be stimulated by very low levels of assimilable carbon, but it is not well understood how identified pathogens respond to the same stimuli (Volk and LeChevallier, 2002). Improving our assessment tools for existing and emerging pathogens is key to public health protection. Useful microbial indicators will 1) focus on organisms significant to public health, 2) have environmentally relevant detection limits and low false positive/negative rates, and 3) have the ability to detect meaningful differences in microbial activity. Another potential source of biological contamination is external contamination. External biological contamination may result from cross-connections, intrusion from the soil which can potentially be contaminated by adjacent sewers, or intentional introduction of bio-contamination by criminal or terrorist groups. Water quality may also be affected by biological activity in premise plumbing. Premise plumbing typically has higher water age than in many parts of the distribution system, leading to lower disinfectant residual and microbial regrowth. Higher temperatures in premise plumbing can also promote microbial activity. Biofilm growth in premise plumbing can cause corrosion of lead and copper piping, exposing customers to these FINAL WHITE PAPER 22 OCTOBER 5, 2007

29 contaminants. Colored water and taste and odor complaints may also originate from biological activity in premise plumbing. Further discussion on premise plumbing is provided below. The understanding of biofilm growth and other regrowth issues in distribution systems is not complete, and substantially more research is needed to develop predictive models and to define the associated public health risks and operational consequences. These objectives may be fulfilled through research focused on the underlying processes and the microbial ecology that develops from these processes. In addition, epidemiology studies are needed to link disease outbreaks with water quality changes, especially in premise plumbing, and assist with the quantification of public health risk. Nitrification The oxidation of free ammonia-n to nitrite by nitrifying bacteria contributes to the loss of chloramine residual and increased nitrite concentrations. When complete nitrification occurs, nitrate is produced. Nitrification can also reduce ph, increasing the likelihood of lead and copper corrosion in premise plumbing. It is yet unknown whether the occurrence of nitrification can cause a violation of the LCR (AWWA and EES, Inc., 2002a). The primary concern with nitrification is reduced disinfectant residual, affecting the inactivation of disease-causing microorganisms (NRC, 2005). Elevated nitrate levels have also been shown to cause certain public health effects. However, the level achievable from nitrification is below those of health concern, unless there is a significant amount of background nitrate in the water and complete nitrification occurs. To date, a few states have recognized the water quality implications associated with nitrification in chloraminated systems and implemented distinct disinfectant residual requirements for chloraminated systems. However, most states have not implemented utility guidance on this issue. Leaching All materials used in constructing and maintaining water distribution systems have the potential to leach substances into the water. These substances primarily cause taste and odor problems (Burlingame et al., 1994; Khiari et al., 2002 per NRC, 2006). However, consumer health may be affected by leaching of lead, aluminum, asbestos, and organic compounds from various materials (AWWA and EES, Inc., 2002b; Berend et al., 2001 per NRC, 2006). Organic chemicals used in linings, joints and sealing materials may also support biofilm growth (Shoenen, 1986). Current ANSI/NSF standards address the public health effects associated with leaching materials, but do not provide requirements on performance, taste and odor, or microbial growth. Only one AwwaRF study has dealt with biodegradation of coatings and linings (Clement et al., 2003). FINAL WHITE PAPER 23 OCTOBER 5, 2007

30 Internal Corrosion, Scale Formation, and Dissolution Corrosion of pipe materials such as iron, lead, and copper, and their release into the water as dissolved or particulate constituents, is highly dependent on distribution system chemistry (e.g. temperature, redox potential, ph). The health impacts of lead and copper are well understood and regulated under the LCR. Iron corrosion generally causes colored or turbid water, but can contribute to possible health effects due to the release of arsenic or other adsorbed substances (Lytle et al., 2004 per NRC, 2006). Iron corrosion typically occurs in the distribution system and in premise plumbing, whereas lead and copper corrosion is a concern in premise plumbing. Internal corrosion is primarily managed by controlling the quality of distributed water. Conventional wisdom suggests that the formation of a thin, smooth calcium carbonate coating of the pipe wall can reduce the potential for corrosion. Many utilities adjust ph and alkalinity in the finished water to precipitate calcium carbonate to create this coating. While ph, alkalinity, and other factors are important to controlling corrosion, the concept of calcium carbonate precipitation and the many so-called calciteprecipitation corrosion indices are inadequate for the control of many forms of corrosion and leaching of toxic metals. New corrosion tools are needed that more accurately describe the corrosion process, and provide information about metal release and predictions of remaining pipe service life. Uncontrolled scale formation may reduce hydraulic capacity and negatively affect water quality by increasing chlorine demand, supporting biofilm growth (Camper et al., 2003 per NRC, 2006), and subsequently releasing contaminants into the water. As with internal corrosion, scales may adsorb contaminants such as uranium, radium-226, and arsenic, and subsequently release these into the water at levels that represent a public health issue (Dodge et al., 2002; Valentine and Stearns, 1994; Lytle et al., 2002 per NRC, 2006). The release of iron scales also contributes to colored water; although, it is not considered a public health concern. The processes which contribute to the accumulation of contaminants and their subsequent release have not yet been fully characterized. Water Quality Consequences Associated with Increased Water Age Increased water age in the distribution system can have two major water quality impacts loss of disinfectant residual (causing several consequences including an increase in microorganisms) and the formation of disinfection by-products (DBPs). Both chlorine and monochloramine concentrations decrease as the length of time the water spends in the distribution system increases. Chlorine loss is primarily attributed to reduction reactions, with NOM, iron, and manganese as primary reductants. Chloramine decay is less understood but is known to occur through numerous mechanisms, including auto-decomposition and reduction by NOM, iron, and nitrite. FINAL WHITE PAPER 24 OCTOBER 5, 2007

31 Chloramine decay releases free ammonia which may induce nitrification, resulting in further disinfectant loss. Reactions between disinfectants and NOM result in the formation of DBPs in the distribution system (Rossman et al., 2001), a process that increases with water age. The DBPs formed may differ between chlorinated and chloraminated systems and formation is slower in the latter. DBPs have also been shown to undergo certain decay processes, which are not currently well characterized within the distribution system (Baribeau et al., 2006; Speight and Singer, 2005; Baribeau et al., 2005a; Zhang and Minear, 2002; Chun et al., 2005 per NRC, 2006). Further, the number and type of DBPs that may form in the distribution system continues to grow as ongoing research identifies new reactions (Richardson and Krasner, 2003; Richardson et al., 2004 per NRC, 2006). As new DBPs are discovered, their public health impact must be investigated and then adequately incorporated into the regulations. Much effort has been invested in developing mathematical models to estimate the decay of both chlorine and chloramine, growth of microorganisms, and DBP formation; however, these have been primarily empirical or semi-mechanistic and based on abiotic reactions. Model refinement is needed to thoroughly describe all reactions and interactions between these processes based on appropriate physical, chemical, and biological mechanisms. Water Quality Degradation in Premise Plumbing A greater proportion, by length, of the water distribution infrastructure exists in premise plumbing than in the distribution system. Several characteristics of premise plumbing cause it to be especially susceptible to the mechanisms of water quality degradation discussed in this white paper. These include excessive water age, the use of lead and copper piping and brass plumbing, high and variable velocities, potential for cross connections, backflow events, and high temperatures. Moreover, because of its proximity to the consumer, there is no opportunity for dilution of a contaminant once it is released from the household plumbing surface. Water quality issues that can get worse in premise plumbing include microbial regrowth and biofilm detachment, disinfectant residual decay, corrosion of pipe materials, and inhalation of volatile DBPs or bioaerosols. Due to these risks to public health, topics related to maintaining water quality in premise plumbing deserve increased attention in future research. Additionally, biological activity in premise plumbing can lead to colored water and taste and odor issues, both unpleasant to the consumer. To initiate workshop discussions, some research needs identified in the Committee Report and in the literature are summarized in Table 2. FINAL WHITE PAPER 25 OCTOBER 5, 2007

32 Table 1. Research Needs Related to Internal Causes of Water Quality Degradation and Their Consequences Topic Research Needs Biofilm Further characterization of the processes leading to biofilm growth, their growth or interactions, and the microbial ecology that arises from these interactions is needed other to improve prediction and risk assessment (NRC, 2006 Chapter 6). biological This characterization shall include the role of phosphorous, nitrogen, or other contamination available substrates on biofilm growth and the importance of their control. Determine the impact of various treatment techniques on nutrient concentrations in finished water and develop treatment schemes to remove limiting nutrients other than carbon (Lehtola et al., 2001; HDR/EES, 2007). Study the role of limiting nutrients in biofilm growth (Lehtola et al., 2002). Determine the effectiveness of source water protection as a method to provide a more biologically stable water, including the impact of climate change and urbanization on nutrient levels (HDR/EES, 2007). Develop more effective measurements (other than AOC and BDOC) to determine biological stability (HDR/EES, 2007). Determine the relative effectiveness of biofilm growth indicators (EPA, 2002b). Research biofilm growth on inert materials such as epoxy, cement, and PVC (Clement et al., 2003). Determine the relationship between disinfectant usage and the risks of pathogenic organisms (NRC, 2006 Chapter 3) Investigate the effect of different disinfectants and residual concentrations on biofilm composition and growth (HDR and Cadmus, 2007). Determine the effectiveness of disinfectant residual on inactivation of biofilm pathogens and reduction of public health risk (HDR and Cadmus, 2007). Determine the impact of seasonal disinfectant changes on biological activity (HDR and Cadmus, 2007). Investigate the development of chlorine-resistance in distribution system species (AWWA, 2007). Develop models to predict sources of pathogens in distribution systems (NRC, 2006 Chapter 3). Model development may integrate research related to the effects of flow regime, disinfectant residual concentrations, and microbial growth (AWWA, 2007). Conduct epidemiology studies focused on disease incidence as a result of distribution system contamination, including premise plumbing (NRC, 2006 Chapter 3). Nitrification Conduct epidemiology studies to further investigate the link between certain cancers, and N-nitroso compounds (De Roos et al., 2003). Leaching Current ANSI/NSF materials standards address health effects, but do not include performance, taste & odor, or microbial growth requirements. Testing should include potential for permeation of contaminants and leaching of compounds that may increase public health risk, cause taste and odor problems, or support biofilm growth (NRC, 2006 Chapter 6). Determine the effect of chloramine on leaching (Sadiq et al., 2006). Determine the impact of pipe age on leaching potential (AwwaRF, 2007). New materials are needed to minimize adverse water quality effects (also related to corrosion and loss of disinfectant residual). This research should address both distribution system and premise plumbing materials (NRC, 2006 Chapter 6). Characterize contaminants that leach from plastic pipes and determine their impact on water quality, regarding both public health and aesthetics (Tomboulian et al., FINAL WHITE PAPER 26 OCTOBER 5, 2007

33 Topic Internal Corrosion, Scale Formation, and Dissolution Loss of Disinfectant Residual DBP Formation Research Needs 2004 per Sadiq et al., 2006). Public health benefits may also arise from research into new, inherently safe treatment chemicals. These chemicals address security concerns with storage and use of harmful substances (AwwaRF, 2007). Study the accumulation and release of metals and other inorganics in the distribution system: Identify distribution system factors that affect accumulation and release, including biofilms, bulk water quality, and treatment practices (HDR, 2006). Determine the relationship between distribution system concentrations and concentrations expected at the customers tap (HDR, 2006). Further characterization of the processes leading to internal corrosion is needed to develop more effective control methods and to optimize the placement of pipe materials with soil conditions. Investigate the role of iron reducing organisms in corrosion processes (AWWSC, Inc., 2002; Sarin, 2004). Determine the effect of microbial activity and disinfectant type and residual on corrosion rate (Ollos et al., 1998 per Sadiq et al., 2006) Incorporate role of NOM in iron corrosion model (Sarin, 2004). Determine the effect of corrosion inhibitors other than orthophosphate on iron release (Sarin, 2004). Investigate internal corrosion and subsequent scale dissolution as a potential source of contamination (NRC, 2006 Chapter 6). Using improved process understanding, develop predictive models. Develop a manual of practice for external and internal corrosion control (NRC, 2006 Chapter 4). Further characterize monochloramine decay reactions (NRC, 2006 Chapter 6). Develop mechanistic models to predict chlorine and monochloramine residual in the distribution system, including effects of microbial activity and corrosion by-products (Vikesland et al., 2000; Vikesland and Valentine, 2002 per Sadiq et al., 2006). Further characterize organochloramine species and disinfectant efficacy. (communication with Charlotte Smith, May 18, 2007) Further develop models of DBP formation and decay, including all relevant processes, to improve predictive capabilities (NRC, 2006 Chapter 6). Determine the relative importance of organic compounds deposited on the pipe wall in DBP formation and incorporate this role into models (NRC, 2006 Chapter 6). Evaluate public health risk of newly identified DBPs and other chlorinated and brominated compounds found in the distribution system (NRC, 2006 Chapter 6). Table 2. Research Needs Related to Premise Plumbing Topic Research Needs Disinfectant Investigate the relationship between water quality and materials used in Decay premise plumbing, especially the kinetics of chlorine and chloramine decay reactions with these materials (NRC, 2006 Chapter 8). Characterize the mechanisms by which chlorine and chloramines decay in premise plumbing and determine the significance of this problem (NRC, 2006 Chapter 8). Cross Determine the contribution of surge in the distribution system to backflow events, including those due to low pressure changes (EPA, 2002a). FINAL WHITE PAPER 27 OCTOBER 5, 2007

34 Topic Connections and Backflow Legionella Contamination Research Needs Quantify the extent, frequency, and magnitude of cross connection control risk nation-wide. Study the importance of building hydraulics on this risk. Determine how to separate the risk from premise plumbing from that of the distribution system (NRC, 2006 Chapter 8). Quantify the problem of under-reporting backflow events and assess the effectiveness of cross connection control and backflow prevention programs (EPA, 2002a). Determine the effect of disinfectant residual on controlling contamination during a backflow event (EPA, 2002a). Determine effects of chloramination and other treatment techniques on Legionella control (NRC, 2006 Chapter 8). Risk Assessment Conduct epidemiology studies to quantify the public health risk associated with water quality changes in premise plumbing. One study should be focused on population subsets particularly prone to these health risks (NRC, 2006 Chapters 3 and 8). Collect data to quantify water quality changes in premise plumbing (NRC, 2006 Chapter 8). Research potential contamination exposure routes on customer premises (NRC, 2006 Chapter 8). Conduct standardized environmental assessments of disease outbreaks to determine cause-and-effect relationships (NRC, 2006 Chapter 8). LCR Compliance Evaluate impacts of utility management measures related to lead and copper: Determine the effect of chloramine conversion on lead and copper release (Edwards and Dudi, 2004; Vasquez et al per Sadiq et al., 2006). Determine impact of new copper plumbing on LCR compliance (Lagos, et al per Sadiq et al., 2006). MONITORING WATER QUALITY DEGRADATION One challenge in detecting the loss of water quality integrity is to distinguish between external contamination and internal degradation. Many parameters currently monitored in the distribution system cannot accurately identify the source of contamination or degradation. This inability may also be related to insufficient sampling design, where the number and frequency of samples is not adequately matched to the process being detected. However, experience and system knowledge may allow the utility to interpret monitoring results in context and produce meaningful conclusions. The Committee Report has placed an emphasis on the development of online, real-time monitoring methods to provide continuous water quality data and assist the utility in quickly determining the nature and extent of contamination events. Future research is needed in chemical and microbial detection techniques to support this type of data collection and improve utility response. The current knowledge on water quality FINAL WHITE PAPER 28 OCTOBER 5, 2007

35 detection, as demonstrated in the Committee Report and the literature, is summarized below. Research topics listed in Table 3 provide an initial point to resolve gaps in this body of knowledge. Taste and Odor Consumer taste and odor complaints often indicate water quality changes in the distribution system (McGuire, 1995 per NRC, 2006). These complaints are often a result of processes occurring within the customers premises (Suffet et al., 1995; Khiari et al., 2002 per NRC, 2006). Internal causes of offensive tastes and odors are attributed to disinfectants (chlorine and monochloramine); certain metals contained in the source water or introduced via corrosion and other distribution system appurtenances; release of organics from new pipe liners, sealants, and joints; and microbial activity. Steps that can be taken to avoid taste and odor problems include maintaining water age, proper use of joints, sealants, and liners, and controlling disinfectant dosages. Color and Turbid Water Colored or turbid water suggests internal degradation due to iron corrosion, release from scales, or precipitation. Precipitation of other metals such as aluminum and magnesium can also cause colored or turbid water. This type of water quality change may be alerted by customer complaints. Dissolved and Particulate Metal Concentrations An increase in metal concentration between the treatment plant and the customer s tap may indicate leaching and internal corrosion. Iron concentrations may increase in the distribution system and lead and copper concentrations may increase in premise plumbing. Lead and copper pose a risk to public health and their concentrations are regulated by the LCR, whereas iron is primarily associated with aesthetic concerns. Disinfectant Residual and DBP Measurements Utilities commonly measure disinfectant residual and DBP concentrations through standard analytical methods. Samples taken in the distribution system may indicate contamination through cross connections, nitrification, internal corrosion, or intentional contamination. Simulated Distribution System jar testing is used to determine the contribution of bulk phase reactions to the total rate of disinfectant loss. Differences between jar tests and system samples may show that processes at the pipe-water interface are occurring. Chloramine loss is generally more difficult to estimate as it degrades via auto-decomposition as well as reduction. Mathematical models or additional jar testing can help in isolating the contribution of this loss mechanism. FINAL WHITE PAPER 29 OCTOBER 5, 2007

36 DBP concentration measurements can take extended periods of time which may prevent timely remedial action by the utility in the event of contamination. Quick, inexpensive DBP field measurements are needed to provide immediate indication of a breach in water quality, allowing adequate time to implement a recovery strategy. Indicators of Nitrification Several indicators have been proposed including disinfectant residual, Nitrite-N, and free ammonia-n, for determining whether nitrification exists in the distribution system. Ammonia oxidizing bacteria (AOB) have been noted as superior indicators of nitrification. However, currently these indicators are of limited usefulness until quick, inexpensive enumeration methods become available (Smith, 2006 per NRC, 2006). Detection of Biological Changes Heterotrophs, coliforms, and pathogens can be monitored to detect water quality changes in the distribution system. Heterotrophic Plate Counts (HPC) can be used as a general indicator of water quality. An increased in HPC suggests water quality degradation; however, with this method it is difficult to identify the cause of increased bacterial growth and whether it poses a threat to public health. This is due to the fact that many distribution system changes, such as changes in organic carbon concentration, disinfectant loss, and nitrification, can lead to an increase in HPC. This method also cannot identify the type of microorganism and does not distinguish between suspended cells, cells released from biofilms, and contamination from an external event. Another common method for detecting biological contamination is the measurement of coliforms, which are regulated under the TCR. Coliform presence in the distribution system may be the result of several contamination events, including fecal contamination, problems maintaining adequate treatment, and growth in biofilms. With coliform growth being dependent on certain water quality parameters, it is difficult to distinguish between these types of contamination by measuring total coliforms. In general, E. coli is linked to external contamination (often fecal). Therefore, this may be used in identifying this source of contamination. As discussed above, neither HPC nor coliform detection is definitive in identifying external contamination events. Therefore, direct detection of pathogens, instead of indicator organisms, has been proposed to identify fecal contamination. Currently, this is not a viable alternative as laboratory culturing methods do not exist for many pathogenic organisms and their low concentrations in the distribution system make them difficult to collect with current sampling methods FINAL WHITE PAPER 30 OCTOBER 5, 2007

37 Recent research in microbial detection techniques have identified several technologies promising for use in assessing water quality in the distribution system. Fluorescent DNA staining, polymerase chain reaction, and other techniques are currently in use, but do not yet provide the quick, inexpensive, and reliable detection methods needed for routine monitoring. Advancements in molecular methods may address these issues in the future. Table 3. Research Needs Related to Water Quality Monitoring Topic Research Needs Taste and Odor No research needs identified in NRC (2006) Color and Turbid Water No research needs identified in NRC (2006) Dissolved and Particulate Metal Concentrations Disinfectant Residual and DBP Measurements Indicators of Nitrification Other Indicators of Biological Contamination Real time and on-line monitoring and data processing Develop monitoring methods to assess risk of certain system components to inorganic accumulation and subsequent release, including sample location, frequency, and parameters. Reliable analytical methods are also needed (HDR, 2006). Develop quick, inexpensive DBP field measurement techniques for on-line, real-time monitoring (NRC, 2006 Chapters 6 and 7). New sampling technologies will also need to address the variability of DBP type and concentration in the distribution system (AwwaRF, 2007). Ammonia oxidizing bacteria (AOB) may be used as an indicator of nitrification quick, inexpensive enumeration techniques are needed to increase its usefulness to utilities (NRC, 2006 Chapters 6 and 7). Develop quick, inexpensive microbial monitoring techniques for online, real-time monitoring (NRC, 2006 Chapters 6 and 7). Standardization and validation studies are needed to gain acceptance from regulators (NRC, 2006 Chapters 6 and 7). See Table 5 MAINTAINING AND RECOVERING DISTRIBUTION SYSTEM WATER QUALITY INTEGRITY Utilities implement several strategies to protect water quality integrity in the distribution system and to recover this integrity when necessary. These strategies must account for both stringent environmental regulations as well as the water quality changes that may occur between the treatment plant and the customer s tap. Once a contamination event occurs, limited methods are available to return water quality to safe levels. Commonly used best management practices for maintaining and recovering water quality integrity, as described in the Committee Report and the literature, are discussed below. Research topics listed in Table 4 are some suggestions to resolve gaps FINAL WHITE PAPER 31 OCTOBER 5, 2007

38 in this body of knowledge and provide further guidance to utilities on maintaining water quality integrity. Adequate Disinfectant Residual Disinfectant residual is used to control biofilm growth and as a protective measure against water quality degradation during an external contamination event. It is required under the Surface Water Treatment Rule and is designated as the Best Available Technology for compliance with the TCR. The concentration of disinfectant residual needed to effectively control biological contamination varies among federal and state regulations and consistent recommendations have yet to be established. Various levels have been published in the literature; however, these studies are based on different microorganisms (e.g. pathogens and coliforms), or different doses that might not be representative of distribution systems and different assumptions regarding the contamination event. Most studies have involved large amounts of contamination and were not conducted in flowing pipes. Whether the value of disinfectant residual is as a sentinel of contamination or a prophylactic in the event of contamination remains a matter of debate. Booster Disinfection Booster chlorination or chloramination facilities are used to increase disinfectant residuals in areas of the distribution system with high water age where disinfectant residual has been significantly reduced. The Committee Report recommends several factors to be considered before choosing to implement booster disinfection. Operations adjustments, such as corrosion control, improving the biostability of the finished water, and reducing water age in storage facilities can all contribute to disinfectant residual maintenance; and should be considered before implementing booster facilities (Hatcher et al., 2004; Grayman et al., 2004 per NRC, 2006). Uber has noted that disinfectant decay rate and trihalomethane (THM) formation data are important in determining whether remote chlorination facilities will affect residual maintenance and THM formation (Uber, 2003 per NRC, 2006). Corrosion Control Specification of non-corrosive pipe materials, the addition of corrosion inhibitors, and controlling water chemistry, such as ph and alkalinity, are all methods used to control corrosion in the distribution system. Low flow conditions can cause the release of corrosion products; therefore, it is important to maintain flowing conditions (Sarin et al., 2004). Corrosion control measures may improve the effectiveness of disinfectants in controlling biofilm growth (LeChevallier et al., 1990, 1993 per NRC, 2006). However, the addition of phosphate-based corrosion inhibitors may increase biological activity in cases where phosphorus is the limiting nutrient (Lehtola et al., 2001, 2004 per NRC, FINAL WHITE PAPER 32 OCTOBER 5, 2007

39 2006). Evidence of phosphorus limitation, rather than organics, appears to be limited to a few studies done in Japan and Finland. Selection of Materials to Control Leaching As discussed previously, iron, lead, and copper pipes are prone to corrosion, which can increase metal concentrations in the water and cause aesthetic and public health impacts. Further, materials such as PVC, asbestos cement, and organics used in linings, joints, and sealings may leach contaminants into the water. Other materials may increase chlorine demand at the pipe wall, decreasing disinfectant residual concentrations (Haas et al., 2002). Through capital and operations and maintenance programs, utilities can address these water quality issues by choosing appropriate materials. Standards related to material properties must be updated to address water quality issues and research is needed to develop new materials less susceptible to leaching. Emerging concerns with the security of public water supplies has prompted research into treatment chemicals that are safe to store and use. As with other changes in distribution system operations and maintenance practices, the impact of these new chemicals on water quality must be addressed through additional research. Further, new, safer treatment chemicals may arise from this research. Flushing Hydrant flushing is commonly utilized by utilities to remove aged water from the distribution system, which is replaced with fresher water of higher quality from other areas in the system. Flushing can address a variety of water quality issues, including low disinfectant residual, colored water, taste and odor, and biofilm growth and bacterial contamination. Spot flushing and conventional flushing are techniques that address localized areas of sediment accumulation. Unidirectional flushing consists of operating system valves and hydrants in a concerted manner to increase system velocities. This action is more effective in removing accumulated sediment, reduces water waste, and provides a means to test several valves and hydrants. Flushing is considered a necessary component of distribution system operations activities and is best implemented when water waste is minimized and the water is properly disposed of. The quality of flushed water is typically not monitored as very few utilities collect water samples during the flushing process (Chadderton et al., 1992 per NRC, 2006). Change Disinfectant It is common for utilities to change from chlorine to chloramine as a disinfectant to improve residual concentrations, eliminate taste and odor issues, and control DBP formation. However, utilities have been both successful and unsuccessful in controlling FINAL WHITE PAPER 33 OCTOBER 5, 2007

40 biofilms (Norton and LeChevallier, 1997; Muylwyk et al., 2001 per NRC, 2006) and several laboratory studies have shown no advantage to chloramine disinfection (Ollos et al., 1998; Clark and Sivaganesan, 2002; Camper et al., 2003 per NRC, 2006). Also, difficulty maintaining adequate water quality through the conversion process has been documented (Edwards and Dudi, 2004 per NRC, 2006). The changes in chemistry attributable to disinfection conversion can cause leaching of materials bound in biofilms and increased coliform levels. Chlorine or chloramine may provide inadequate inactivation during an external contamination event, depending on the magnitude and media in which the bacteria are suspended. Temporary disinfectant changes have also been practiced in reaction to nitrification events. Breakpoint chlorination in storage tanks is sometimes used to address nitrification by temporarily inactivating nitrifying bacteria, however this method is short lived (NRC 2006), and there is some concern regarding short-term exposure to DBPs that may result from this method (Hatcher et al., 2004 per NRC, 2006). Point-of-use Treatment Devices Point-of-use (POU) and point-of-entry (POE) devices are commonly used to treat water between the distribution system and the customers tap. Such devices can potentially play a significant role in future distribution systems where the nature of centralized treatment might change. These devices can be designed to treat many constituents, including organic and inorganic chemicals and biological contaminants that may result from water quality changes in premise plumbing. However, there are cases in which they can be ineffective in controlling contamination. For example, a POE device will not address a cross connection connected after the device. Also, media contained in the treatment system are susceptible to microbial regrowth, which can increase concentrations in the water. While third party testing protocols are available (NSF International), there is no national standard that requires device testing and certification. Table 4. Research Needs Related to Protecting Water Quality Integrity Topic Research Needs Disinfectant Residual Develop standards for residual concentrations needed to address both internal and external contamination events (NRC, 2006 Chapter 6); and standards for using disinfectant residual as an indicator of biological contamination (HDR and Cadmus, 2007). Investigate the differences in disinfectant demands associated with chlorine and chloramines among various contamination events (HDR and Cadmus, 2007). Determine the effectiveness of disinfectant residual for controlling contamination due to malevolent attack (HDR and Cadmus, 2007). Investigate relationship between disinfectant residual and contact time variability between contamination location and consumers taps (LeChevallier et al., 1996). FINAL WHITE PAPER 34 OCTOBER 5, 2007

41 Topic Research Needs Booster Disinfection Optimize booster chloramination (NRC, 2006 Chapter?) Corrosion Control See Internal Corrosion topic in Table 1. Materials See Leaching topic in Table 1. Specification Flushing Develop protocols for sampling and analysis during flushing to assess effectiveness (NRC, 2006 Chapter 6). Determine the effectiveness of flushing as a method of controlling the accumulation and release of inorganic contaminants and identify other effective control methods (Case and Albert, 2007). Change Disinfectant Identify and study issues related to chloramine conversion (as previously noted in Tables 1 and 2). INTEGRATING RESEARCH AND TECHNOLOGY WITH WATER QUALITY MANAGEMENT The Committee Report and other literature have provided guidance for research needs intended to develop knowledge, tools, and policies to assist utilities in effectively managing water quality within the distribution system, reducing risks to public health and improving system operation. Research needs are focused on the processes underlying water quality changes, detection of these changes, and measures taken to restore water quality. The tools envisioned for future water quality management include continuous water quality data collection devices; data transmission, storage and management systems; and models to transform collected data into useful information. This information can then be entered into decision-support systems to predict the nature and extent of contamination and water quality deterioration, and thus to enhance remedial measures for utility staff. Table 5 summarizes some research suggested to integrate the technologies discussed above in support of assessing and reducing water quality deterioration in the distribution system. Table 5. Research Needs Related to Water Quality Management Topic Research Needs Water Quality Develop methodology for utilities to develop a water quality Monitoring sampling and monitoring plan that meets multiple objectives operations, regulatory compliance, and customer service (AWWA, 2007). Develop on-line, real-time water quality monitoring devices for chemical and biological constituents indicative of water quality integrity (NRC, 2006 Chapter 7). Develop models to optimize the number and location of on-line, realtime monitoring devices (Uber et al., 2004b per NRC, 2006). FINAL WHITE PAPER 35 OCTOBER 5, 2007

42 Topic Hydraulic and Water Quality Modeling Decision-Support Systems Research Needs Develop data analysis tools to effectively utilize data from on-line, real-time monitors, including the integration of hydraulic, water quality, and operational data (NRC, 2006 Chapter 7). Develop models to predict the fate and transport of multiple interacting chemical and biological constituents (Uber et al., 2004a per NRC, 2006). Develop capabilities within water quality and hydraulic models to allow real-time analysis (NRC, 2006 Chapter 7). Implement high-speed data loggers and surge modeling to predict intrusion events (NRC, 2006 Chapter 7). Improve model development and calibration techniques and standards (NRC, 2006 Chapter 7). Integrate data collection and management systems and multi-criteria decision-support models to evaluate data and provide feedback to utility personnel (NRC, 2006 Chapter 7). SUMMARY The recently published NRC report titled Drinking Water Distribution Systems: Assessing and Reducing Risks outlined the research activities needed to fully address distribution system physical, hydraulic, and water quality integrity. The knowledge summaries and research needs presented in this white paper, taken from the Committee Report and other literature, are intended to provide the framework for developing a 5-year research plan to begin this research. Some research suggestions have been provided in Tables 1 through 5 as a starting point for the Expert Workshop. The following broad categories summarize the specific research projects suggested in the tables above. As many of the water quality issues identified in the Committee Report are a matter of interactions between both chemical and biological changes that are also dependent on the physical and hydraulic integrity of the distribution system, further progress in this area would benefit from an increase in interdisciplinary research. 1. Fundamental Processes and Mechanisms. In general, the fundamental principles of internal chemical and biological processes need to be further characterized. These include biofilm growth, disinfectant decay, DBP formation and decay, and internal corrosion. Ultimately, the ability to describe these processes will allow models to be applied universally, improving the identification of contamination events and the efficiency of the decision-making process. These models may also be incorporated with current hydraulic models, providing a tool capable of predicting likely contamination sources and the system areas affected by internal water quality deterioration or external contamination. FINAL WHITE PAPER 36 OCTOBER 5, 2007

43 2. Health Risk Assessment. Assessing the public health risk of distribution system contamination is a difficult task as limited data is available to link water quality changes to increased incidence of certain health problems, especially in sensitive population subsets. Additional data to characterize the spatial and temporal dynamics of contamination events are needed to evaluate current exposure assessment and regulatory approaches. Epidemiological studies will identify exposure pathways and quantify the risk of certain contamination events. Further study into the physiological effects of distribution system contaminants will identify public health issues and susceptible populations. 3. Monitoring Capabilities. Field analytical capabilities are in need of improvement to provide quick, inexpensive analysis to support operations decisions. On-line and real-time monitoring allow utilities to constantly monitor conditions in the distribution system and react quickly to adverse conditions that may impact public health. The monitoring capabilities should be extended to analyses related to DBP concentrations and indicators of nitrification, corrosion, and microbial activity. Continuously collected data can support real-time water quality and hydraulic modeling and provide the basis for a comprehensive utility decision-support system. 4. Materials. The materials used in distribution construction and maintenance have a significant impact on water quality, contributing to contamination through corrosion and leaching. Research is needed to improve understanding of the processes causing these conditions and to develop new materials that are not prone to these types of contamination. Utilities will benefit from this research as new material standards are developed to address water quality changes as well as structural integrity. 5. Water Quality Maintenance and Recovery. Utilities use various practices such as booster disinfection, flushing, corrosion control, etc to maintain the water quality integrity within their distribution systems and in premise plumbing. It is important to develop performance measures to quantify the effectiveness of these practices. FINAL WHITE PAPER 37 OCTOBER 5, 2007

44 REFERENCES American Water Works Service Co., Inc (AWWSC) Deteriorating buried infrastructure management challenges and strategies. Washington, DC: EPA. American Water Works Association (AWWA) A review of distribution system monitoring strategies under the Total Coliform Rule. Washington, DC: EPA. AWWA and EES., Inc. 2002a. Nitrification. Washington, DC: EPA. AWWA and EES., Inc. 2002b. Permeation and Leaching. Washington, DC: EPA. AwwaRF staff AwwaRF Session: Brainstorming Research Needs for the Future (draft notes). AWWA Distribution System Research Symposium. March, 2007, Reno, NV. Baribeau, H., S.W. Krasner, R. Chinn, and P.C. Singer Impact of biomass on the stability of HAAs and THMs in a simulated distribution system. J. Amer. Water Works Assoc. 97(2): Baribeau, H Chapter 6: Growth and Inactivation of Nitrifying Bacteria. In: Fundamentals and Control of Nitrification in Chloraminated Drinking Water Distribution Systems. AWWA Manual M56. Denver, CO: AWWA. Berend, K., G. Van Der Voet, and W.H. Boer Acute aluminum encephalopathy in a dialysis center caused by a cement mortar water distribution pipe. Kidney International 59(2): Boyd, G.R., N.K. Tarbert, R.J. Oliphant, G.J. Kirmeyer, B.M. Murphy, and R.F. Serpente Lead pipe rehabilitation and replacement techniques for drinking water service: review of available and emerging technologies. Tunneling and Underground Space Technology 15(1): Boyd, G.R., P. Shetty, A.M. Sandvig, and G.L. Pierson Lead in tap water following simulated partial lead pipe replacements. Journal of Environmental Engineering 130(10): Burlingame, G., J. Choi, M. Fadel, L. Gammie, J. Rahman, and J. Paran Sniff new mains before customers complain. Opflow 20:10:3. FINAL WHITE PAPER 38 OCTOBER 5, 2007

45 Camper, A.K., K. Brastrup, A. Sandvig, J. Clement, C. Spencer, and A.J. Capuzzi Impact of distribution system materials on bacterial regrowth. J. Amer. Water Works Assoc. 95(7): Case, T. and J. Albert Total Coliform Rule / Distribution System Rule Infrastructure Reliability Research Needs for 2007 (draft). Chadderton, R.A., G.L. Christensen, and P. Henry-Unrath Implementation and Optimization of Distribution System Flushing Programs. Denver, CO: AWWA and AwwaRF. Chun, C.L., R.M. Hozalski, and T.A. Arnold Degradation of drinking water disinfection by-products by synthetic goethite and magnetite. Environ. Sci. Technol. 39(21): Clark, R.M. and M. Sivaganesan Predicting chlorine residuals in drinking water: a second order model. J. Water Resources Planning and Management. 128(2): Clement, J., C. Spencer, A.J. Capuzzi, A. Camper, K. Van Andel, A. Sandvig Influence of Distribution System Infrastructure on Bacterial Regrowth. Denver, CO: AwwaRF. De Roos, A.J., M.H. Ward, C.F. Lynch, and K.P. Cantor Nitrate in public water supplies and the risk of colon and rectum cancers. Epidemiology 14(6): Dodge, D.J., A.J. Francis, J.B. Gillow, G.P. Halada, and C.R. Clayton Association of uranium with iron oxides typically formed on corroding steel surfaces. Environ. Sci. Technol. 36(16): Edwards, M. and A. Dudi Role of chlorine and chloramines in corrosion of leadbearing plumbing materials. J. Amer. Water Works Assoc. 96(10): Environmental Protection Agency (EPA). 2002a. Potential Contamination Due to Cross- Connections and Backflow and the Associated Health Risks. Washington, DC: EPA. EPA. 2002b. Health Risks from Microbial Growth and Biofilms in Drinking Water Distribution Systems. Washington, DC: EPA. Friedman, M.J., K. Martel, A. Hill, D. Holt, S. Smith, T. Ta, C. Sherwin, D. Hiltebrand, P. Pommerenk, Z. Hinedi, and A. Camper Establishing Site Specific Flushing Velocities. Denver, CO: AWWA and AwwaRF. FINAL WHITE PAPER 39 OCTOBER 5, 2007

46 Grayman, W.M., L.A. Rossman, R.A. Deininger, C.D. Smith, C.N. Arnold, and J.F. Smith Mixing and Aging of Water in Distribution System Storage Facilities. J. Amer. Water Works Assoc. 96(9): Haas, C.N., M. Gupta, R. Chitluru, and G. Burlingame Chlorine Demand in Disinfecting Water Mains. J. Amer. Water Works Assoc. 94(1): Hatcher, M., W. Grayman, C. Smith, and M. Mann Monitoring and modeling of the Sweetwater Authority distribution system to assess water quality. In: Proceedings of the AWWA Annual Conference. Denver, CO: AWWA. HDR/EES, Inc Effect of treatment on nutrient availability. Washington, DC: EPA. HDR Engineering, Inc Inorganic contaminant accumulation in potable water distribution systems. Washington, DC: EPA. HDR Engineering, Inc. and the Cadmus Group, Inc The effectiveness of disinfectant residuals in the distribution system. Washington, DC: EPA. Khiari, D., S. Barrett, R. Chinn, A. Bruchet, P. Piriut, L. Matia, F. Ventura, I. Suffett, T. Gittelman, and P. Leutweiler Distribution Generated Taste-And-Odor Phenomena. Denver, CO: AwwaRF. Lagos, G.E., C.A. Cuadrado, M.V. Letelier Aging of copper pipes by drinking water. J. Amer. Water Works. Assoc. 93(11): LeChevallier, M.W., B.H. Olson, and G.A. McFeters Assessing and Controlling Bacterial Regrowth in Distribution Systems. Denver, CO: AWWA. LeChevallier, M.W., C.D. Lowry, R.G. Lee, and D.L. Gibbon Examining the relationship between iron corrosion and the disinfection of biofilm bacteria. J. Amer. Water Works Assoc. 85(7): LeChevallier, M.W., N.J. Welch, and D.B. Smith Full-scale studies of factors related to coliform regrowth in drinking water. Appl. Environ. Microbiol. 62(7): Lehtola, M.J., I.T. Miettinen, T. Vartiainen, T. Myllykangas, and P.J. Martikainen Microbially available organic carbon, phosphorus, and microbial growth in ozonated drinking water. Water Res. 35(7): Lehtola, M.J., I.T. Miettinen, M.M. Keinanen, T.K. Kekki, O. Laine, A. Hirvonen, T. Vartianen, and P.J. Martikaninen Microbiology, chemistry, and biofilm FINAL WHITE PAPER 40 OCTOBER 5, 2007

47 development in a drinking water distribution system with copper and plastic pipes. Water Res. 38(17): Lytle, D.A., T.J. Sorg, and C. Frietch The significance of arsenic-bound solids in drinking water distribution systems. In: Proceedings of the AWWA Water Quality Conference. Seattle, WA. Lytle, D.A., T.J. Sorg, and C. Frietch The accumulation of arsenic in water distribution systems. Environ. Sci. Technol. 38(20): McGuire, M.J Off-flavor as the Consumer s Measure of Drinking Water Safety. Water Sci. Technol. 31(11):1-8. Muylwyk, Q., J. MacDonald, and M. Klawunn Success! Switching from chloramines to chlorine in the distribution system: results from a one year full-scale trial. In: Proceeding of the Water Quality Technology Conference. Denver, CO: AWWA. National Research Council (NRC) Public Water Supply Distribution Systems: Assessing and Reducing Risks. Washington, DC: National Academies Press. NRC Drinking Water Distribution Systems: Assessing and Reducing Risks. Washington, DC: National Academies Press. Norton, C.D., and M.W. LeChevallier Chloramination: its effect on distribution water quality. J. Amer. Water Works Assoc. 89(7): Ollos, P.J., R.M. Slawson, and P.M. Huck Bench scale investigations of bacterial regrowth in drinking water distribution systems. EPA-600/S Washington, DC: EPA. Richardson, S.D. and S.W. Krasner Disinfection by-products and other emerging contaminants in drinking water. Trac-Trends in Analytical Chemistry 22(10): Richardson, S.D., H.S. Weinberg, S.W. Krasner, and A.D. Thruston Nationwide DBP Occurrence Study. EPA-600-R Athens, GA: EPA NERL. Rossman, L.A., R.A. Brown, P.C. Singer, J.R. Nuckols DBP formation kinetics in a simulated distribution system. Water Res. 35(14): Sadiq, R., S.A. Imran, and Y. Kleiner Examining the Impact of Water Quality on the Distribution Infrastructure Integrity (draft). Denver, CO: AwwaRF. FINAL WHITE PAPER 41 OCTOBER 5, 2007

48 Sarin, P., V.L. Snoeyink, D.A. Lytle, and W.M. Kriven Iron corrosion scales: model for scale growth, iron release, and colored water formation. J. Environmental Engineering 130(4): Schoenen, D Microbial growth due to materials used in drinking water systems. In: Biotechnology, Vol. 8. H.J. Rehm and G. Reed (eds.). Weinheim: VCH Verlagsgesellschaft. Smith, C Monitoring for Nitrification Prevention and Control. Chapter 7 In: Fundamentals and Control of Nitrification in Chloraminated Drinking Water Distribution Systems. AWWA Manual M56. Denver, CO: AwwaRF. Speight, V.L. and P.C. Singer Association between residual chlorine loss and HAA reduction in distribution systems. J. Amer. Water Works Assoc. 97(2): Suffet, I.H., J. Ho, D. Chou, D. Khiari, and J. Mallevialle Taste-and-Odor Problems Observed During Drinking Water Treatment. Pp 1-21 In: Advances in Taste-and-Odor Treatment and Control. I.H. Suffet, J. Mallevialle, and E. Kawczynski (eds.). Denver, CO: AwwaRF. Tomboulian P., L. Schweitzer, K. Mullin, J. Wilson, and D. Khiari Materials used in drinking water distribution systems: Contribution to taste-and-odor. Water Sci. Technol. 49(9): Uber, J.G Maintaining Distribution System Residuals through Booster Chlorination. Denver, CO: AwwaRF. Uber, J., R. Janke, R. Murray, and P. Meyer. 2004a. Greedy Heuristic Methods for Locating Water Quality Sensors in Distribution Systems. World Water & Environmental Resources Congress, EWRI-ASCE. Reston, VA: Environmental & Water Resources Institute of the American Society of Civil Engineers. Uber, J. F. Shang, and L. Rossman. 2004b. Extensions to EPANET for Fate and Transport of Multiple Interacting Chemical or Biological Components. World Water & Environmental Resources Congress, EWRI-ASCE. Reston, VA: Environmental & Water Resources Institute of the American Society of Civil Engineers. Valentine, R.L. and S.W. Stearns Radon release from water distribution system deposits. Environ. Sci. Technol. 28(3): van der Leeden, F., F.L. Troise, and D.K. Todd Water quality. Pp In: The Water Encylopedia, Second Edition. Chelsea, MI: Lewis Publishers. FINAL WHITE PAPER 42 OCTOBER 5, 2007

49 Vasquez, F.A., R. Heaviside, Z. Tang, J.S. Taylor Effect of free chlorine and chloramines on lead release in a distribution system. J. Amer. Water Works Assoc. 98(2): Vikesland, P.J., R.L. Valentine, B.D. Angerman, S.A. Hackett, M. Shoup, and S. Slattenlow The Role of Pipe-Water Interface in DBP Formation and Disinfectant Loss. Denver, CO; AwwaRF and AWWA. Vikesland P.J. and R.L. Valentine Modeling the kinetics of ferrous iron oxidation by monochloramine. Environ. Sci. Technol. 36(4): Volk, C.J. and M.W. LeChevallier Effects of conventional treatment on AOC and BDOC levels. J. Amer. Water Works Assoc. 94(6): Zhang, X.R. and R.A. Minear Decomposition of trihaloacetic acids and formation of the corresponding trihalomethanes in drinking water. Water Res. 36(14): FINAL WHITE PAPER 43 OCTOBER 5, 2007

50 APPENDIX B RECOMMENDED PROJECT DESCRIPTIONS WORKSHOP REPORT 44 OCTOBER 5, 2007

51 REQUEST FOR PROPOSALS ROLE OF BIOFILM ON THE FATE AND TRANSPORT OF WATERBORNE PATHOGENS IN DISTRIBUTION SYSTEMS AND PREMISE PLUMBING Objective: This research will focus on understanding the retention, fate, persistence, and potential for release of microorganisms from biofilms, as well as possible control approaches that can be used to impact growth, retention, and release of the microorganisms from biofilms. An outcome of this study should be the ability to create mass balances on pathogens across a system. The researcher should also consider the needs of possible epidemiological studies of the impacts of distribution system and premise plumbing biofilms in understanding the risk of waterborne outbreaks. Recommended Budget: $600K Controversial Issues: No controversial issues have been identified. Background: Pathogenic organisms may enter distribution systems through treatment breakthrough, inadvertent contamination of the distribution system (main breaks, back siphoning, breaches in storage tanks, etc.) or deliberate contamination such as in a bioterrorism event. Presumably, these organisms would be transported through the distribution system and potentially impacted by the presence of a secondary disinfectant residual. This view may be simplistic, however, since the introduced deleterious organisms may interact with the surfaces of the distribution system and they can become entrained in biofilms. Cryptosporidium oocysts (Rogers and Keevil, 1995: Searcy et al, 2006), Escherichia coli (Banning et al, 2003; Camper et al, 1996; Li et al, 2006), Pseudomonas aeruginosa (Banning et al, 2003), Helicobacter (Mackay et al, 1998), Mycobacterium (September et al, 2004), Legionella (Längmark et al, 2005; Liu et al, 2006; Rogers et al, 1994; Rogers and Keevil, 1992), and coliforms (Camper et al, 1991; McMath et al, 1999) have all been demonstrated to concentrate in drinking water biofilms relative to the bulk fluid. 45

52 In the case of opportunistic pathogens such as Mycobacteria and Legionella, there is evidence that these organisms can reproduce and persist in components of water systems. The fate of organisms that cannot grow in the absence of a host is not as clear. Perhaps these organisms are inactivated via competition with the existing microflora, or it may be that they become dormant and persist for indefinite periods of time. In the case of both types of pathogens, problems arise only if they are detached from the surface and enter the water that is then consumed/comes in contact with the consumer. To impart a public health risk, these organisms must also still be viable or infective. Although there is research currently being done to investigate the public health risk associated with pathogen retention in biofilms, there is very little being done to investigate the fate, persistence, and potential for release of these organisms in drinking water systems. Additional references include two current AwwaRF projects. Project 4087 Assessing and Managing Biofilm in Distribution Systems : This project will develop utility-friendly guidance on assessing and managing distribution system biofilms. It will also present current state-of-thescience knowledge on biofilms in a practical format that is helpful to utility staff and other end users. Project 4092 The Role of Amoebae in the Protection and Proliferation of Pathogens in Distribution Systems will determine the extent to which amoebae shelter pathogenic organisms and enable proliferation of pathogens such as Legionella and Macobacterium avium complex in distribution systems. Research Approach: This project will primarily focus on laboratory and pilot scale work to reduce variability, but the systems should be designed to resemble premise plumbing and distribution system conditions as much as possible. Therefore, there should be an emphasis on mixed population, indigenous biofilms and realistic water quality conditions. Water quality selections should include a range of relevant organic carbon loads and the application of chlorine and monochloramine. The investigator should provide a clear description of the detection methods that will be used for the pathogens and provide evidence that they can adequately enumerate the targets. In addition, activity methods should be provided. The project should focus on at least one opportunistic pathogen (i.e. Legionella or Mycobacteria) and one frank bacterial pathogen and a relevant virus. The pathogens of interest, and reasons for their selection, should be specified in the proposal. In addition, methods to impact retention, viability, and release of the microorganisms should also be investigated. Investigations should focus on not only the biofilm, but the number, frequency, and viability/infectivity of the pathogens in the water phase. If possible, the investigators should collaborate with those involved in the project entitled Microbial Ecology of Piped Water with Respect to Health Risks so that the general ecology of these biofilms can be characterized. References: Banning, N., Toze, S., Mee, B.J. (2003) Persistence of biofilm-associated Escherichia coli and Pseudomonas aeruginosa in groundwater and treated effluent in a laboratory model system. Microbiology 149:

53 Camper, A.K., Jones, W.L., Hayes, J.T. (1996) Effect of growth conditions and substratum composition on the persistence of coliforms in mixed-population biofilms. Appl. Environ. Microb. 62(11): Camper, A.K., Mcfeters, G.A., Characklis, W.G., Jones, W.L. (1991) Growth-kinetics of coliform bacteria under conditions relevant to drinking-water distribution-systems. Appl. Environ. Microb. 57(8): Längmark, J., Storey, M.V., Ashbolt, N.J., Stenström, T. (2005) Accumulation and fate of microorganisms and microspheres in biofilms formed in a pilot-scale water distribution system. Appl. Environ. Microb. 71(2): Li, J., McLellan, S., Oyawa, S. (2006) Accumulation and fate of green fluorescent labeled Escherichia coli in laboratory-scale drinking water biofilters. Water Res. 40(16): Liu, Z., Lin, Y.E., Stout, J.E., Hwang, C.C., Vidic, R.D., Yu, V.L. (2006) Effect of flow regimes on the presence of Legionella within the biofilm of a model plumbing system J. Appl. Microb. 101(3): Mackay, W.G., Gribbon, L.T., Barer. M.R., Reid, D.C. (1998) Biofilms in drinking water systems A possible reservoir for Helicobacter Pylori. Water Science Tech. 38(12): McMath, S.M., Sumpter, C., Holt, D.M., Delanoue, A., Chamberlain, A.H.L. (1999) The fate of environmental coliforms in a model water distribution system. Letters in Appl. Microb. 28(2): Rogers, J., Dowsett, A.B., Dennis, P.J., Lee, J.V. and Keevil.,C.W. (1994). Influence of materials on biofilm formation and growth of Legionella pneumophila in potable water systems. Appl. Environ. Microbiol. 60(6): Rogers, J., and Keevil, C.W. (1992). Immunogold and fluorescein immunolabelling of Legionella pneumophila within an aquatic biofilm visualized by using episcopic differential interference contrast microscopy. Appl. Environ. Microbiol. 58(7): Rogers, J. and C.W. Keevil Survival of Cryptosporidium parum oocysts in biofilm and planktonic samples in a model system. In: Protozoan Parasites and Water. W.B Betts, P. Casemore, C. Fricker, H. Smith and J. Watkins, eds. Royal Society of Chemistry, U.K. Searcy, K.E., Packman, A.I., Atwill, E.R., Harter, T. (2006) Capture and retention of Cryptosporidium parvum oocysts by Psuedomonas aeruginosa biofilms. Appl. Environ. Microb. 72(9):

54 September, S.M., Brözel, V.S., Venter, S.N. (2004) Diversity of nontuberculoid Mycobacterium species in biofilms of urban and semiurban drinking water distribution systems. Appl. Environ. Microb. 70(12):

55 REQUEST FOR PROPOSALS EFFICACY OF SECONDARY DISINFECTION FOR PATHOGEN CONTROL Objective: To assess the net health benefit of maintaining a secondary disinfectant in potable distribution systems for pathogen control in biofilms. Recommended Budget: $300K Controversial Issues: Regulations are based on the assumption that a secondary disinfectant in the distribution system provides a net health benefit; whereas it may only provide a convenient monitoring analyte for system integrity. Background: The likely inability of a chlorine residual to control pathogen intrusion events has been raised for some time (Payment, 1999, Propato and Uber, 2004) and AwwaRF Project 2771 has documented a residual s impact on suspended microorganisms. Further, there are two classes of pathogens that need to be targeted in distribution systems, frank (fecal pathogens) and indigenous (opportunistic pathogens that may grow in distribution system biofilms) (Ashbolt, 2003; Vaerewijck et al., 2005; Hilborn et al., 2006). Inactivation of freely suspended pathogens (viral, bacterial and parasitic protozoan) by a range of disinfectants is relatively well described. However, biofilm and amoeba-associated pathogens are known to be well protected from free chlorine (Långmark et al., 2005; Storey et al., 2004a; Storey et al., 2004b; Daly et al., 1998) and possibly to a lesser degree to chloramines (Howard & Inglis, 2005; Williams & Braun-Howland, 2003). There is a health trade-off between reducing pathogens via chemical disinfection and the production of carcinogenic disinfection byproducts (DBPs). In addition, there are different pathways of human exposure to waterborne pathogens, largely ingestion and inhalation from potable waters, and predominantly inhalation and contact with fomites with non-potable waters (Boone & Gerba, 2007). 49

56 Relevant AwwaRF references include the following projects. Project 2771 Impacts of Distribution System Water Quality on Disinfection Efficacy assesses the impact of dynamic water quality conditions in the distribution system on the inactivation of microorganisms in bulk water. It addresses questions about the usefulness of maintaining a secondary residual and the target level to be maintained. It bridges research related to distribution system water quality with that of microbial inactivation. Project 2760 Optimizing Chloramine Treatment, Second Edition synthesizes all relevant research, operational, and practical information on the use of chloramines in water treatment. It also includes new utility case studies in an updated best management practices manual on chloramine optimization that will have an operations and implementation focus. Project 3134 Contaminant Candidate List Viruses: Evaluation of Disinfection Efficacy will identify and fill gaps in existing literature on disinfection efficacies of viruses listed on the Contaminant Candidate List (CCL) to increase understanding of the extent of inactivation of viruses by common disinfectants used in drinking water treatment. Research Approach: Review and justify appropriate laboratory biofilm reactors, test organisms, and relevant water quality conditions to be used that address potable distribution system conditions. The disinfectants to be studied should include typical free chlorine and chloramine doses expected in distribution systems across the USA. A range of typical water qualities, along with the variable DBP formation potential associated with those waters, should also be used to predict DBP concentrations to be considered for this study. A range of representative pathogens need to be systematically incorporated into the test biofilms and inactivation rates within biofilms studied under controlled conditions, with suspended microbe controls in parallel studies that provide at least 3-log reductions of the test microorganisms. Frank pathogens to be addressed should include representatives for human caliciviruses, adenoviruses, E. coli O157:H7 and Giardia lamblia. Indigenous pathogens to be assessed should include representatives for Legionella pneumophila, Mycobacterium avium complex, Aeromonas hydrophila and Helicobacter pylori. The disinfection results acquired above should be related to the potential for the formation of disinfection by-products under the same conditions. In this way, the relative health risks from these pathogens can be related to the relative risks contributed by the DBPs. Then, by utilizing previous risk assessment and epidemiological studies, the project team should provide a summary for the industry describing the pros and cons of providing a secondary chemical disinfectant in potable distribution systems across the USA. References Ashbolt, N.J. (2003) Chapter 9: Methods to identify and enumerate frank and opportunistic bacterial pathogens in water and biofilms. In Heterotrophic Plate Counts and Drinkingwater Safety. The Significance of HPCs for Water Quality and Human Health, pp Edited by J. Bartram, J. Cotruvo, M. Exner, C. Fricker & A. Glasmacher. London: IWA Publishing. Boone, S.A. & Gerba, C.P. (2007) Significance of fomites in the spread of respiratory and enteric viral disease. Appl. Environ. Microbiol. 73(6):

57 Daly, B., Betts, W.B., Brown, A.P. & O'Neill, J.G. (1998) Bacterial loss from biofilms exposed to free chlorine. Microbios 96(383), Hilborn, E.D., Covert, T.C., Yakrus, M.A., Harris, S.I., Donnelly, S.F., Rice, E.W., Toney, S., Bailey, S.A. & Stelma, G.N., Jr. (2006) Persistence of nontuberculous mycobacteria in a drinking water system after addition of filtration treatment. Appl. Environ. Microbiol. 72(9): Howard, K. & Inglis, T.J.J. (2005) Disinfection of Burkholderia pseudomallei in potable water. Water Res. 39(6): Långmark, J., Storey, M.V., Ashbolt, N.J. & Stenström, T.A. (2005) Biofilms in an urban water distribution system: measurement of biofilm biomass, pathogens and pathogen persistence within the Greater Stockholm Area, Sweden. Water Sci. and Technol. 52(8): Payment, P. (1999) Poor efficacy of residual chlorine disinfectant in drinking water to inactivate waterborne pathogens in distribution systems. Canadian Journal of Microbiology 45(8): Propato, M. and J.G. Uber. (2004). Vulnerability of water distribution systems to pathogen intrusion: how effective is a disinfectant residual? Env. Sci. and Technol. 38(13): Storey, M.V., Långmark, J., Ashbolt, N.J. & Stenström, T.A. (2004a) The fate of legionellae within distribution pipe biofilms: measurement of their persistence, inactivation and detachment. Water Sci. and Technol. 49(11-12): Storey, M.V., Winiecka-Krusnell, J., Ashbolt, N.J. & Stenström, T.A. (2004b) The efficacy of heat and chlorine treatment against thermotolerant Acanthamoebae and Legionellae. Scandinavian Journal of Infectious Diseases 36(9): Vaerewijck, M.J., Huys, G., Palomino, J.C., Swings, J. & Portaels, F. (2005) Mycobacteria in drinking water distribution systems: ecology and significance for human health. FEMS Microbiol. Rev. 29(5): Williams, M.M. & Braun-Howland, E.B. (2003) Growth of Escherichia coli in model distribution system biofilms exposed to hypochlorous acid or monochloramine. Appl. Environ. Microbiol. 69(9):

58 REQUEST FOR PROPOSALS LEAD AND COPPER CORROSION CONTROL IN NEW CONSTRUCTION Objective: The objective of this research is to develop guidance for water utilities that oversee or respond to contractors, plumbers, and construction managers of new or rehabilitated plumbing construction describing steps to minimize lead and copper corrosion problems. The project will establish procedures for properly flushing new building plumbing, including flushing times and velocities. Procedures on lead and copper sampling will also be addressed. The effects of in-building pipe disinfection on corrosion will be investigated, leading to specific recommendations regarding this practice. Recommended Budget: $450K Controversial Issues: This important issue of how to handle new construction is not under direct control of water utilities, and so at this time if new understanding is developed on these topics, the route to practical use and implementation of those results is unclear. The activities of concern in this project are primarily under the control of contractors/plumbers/ and construction managers working on new construction. Thought must be given to routes of use of new information prior to commencement of work on this project. This is particularly important in light of the fact that such follow-up is clearly outside the responsibilities of individual water utilities, and also outside the current focus and responsibilities of AwwaRF, USEPA, etc.. In fact, it is suggested that a plan for engagement of relevant groups representing contractors, plumbers (possibly PMI, Plumbing Manufacturer s Institute), and the construction industry should be identified, and appropriate follow-up groups from the water community (possibly a group such as AWWA, or ASDWA, or EPA) engaged, prior to significant work on this topic. If engaged early on, the concerns of these groups regarding the research or the guidance that might result from the research can be built into the development of the approach to result in more robust results. Background: It is well understood that the Environmental Protection Agency (EPA) Lead and Copper Rule targets lead leaching in older high risk homes with lead solder and lead pipe. It is also known 52

59 that these homes tend to be amongst the lowest risk homes relative to copper leaching or lead leaching from brass. Indeed, there have been several recent cases in which groups of new buildings and homes in a system have been tested with lead and copper well over EPA action limits, yet the water utility monitoring based on testing per the Lead and Copper Rule in older homes suggests that corrosion control has been optimized. For example, there was recently a well-publicized case at the University North Carolina at Chapel Hill where elevated lead was identified throughout several new buildings on campus., The potential controversy about lead in new buildings from brass is now fairly well vetted in peer reviewed literature. Even in cases where brass meets Federal and National Sanitation Foundation (NSF) test protocol, the leaching of lead may be excessive. The well-intentioned disinfection of premise plumbing systems could potentially cause corrosion problems in some cases. The water industry needs a strategy to address lead and copper problems in new buildings. Ultimately, the installation procedures, types of materials used, and flushing protocols exert an influence on the persistence of these problems, as well as the general corrosivity of the water to new plumbing. Elevated lead and copper levels can be reduced with guidance on how to properly install and commission such systems and recommendations for brass with lower leaching propensity. From a utilities perspective, in a few cases, it appears that a change in disinfectant regime from chlorine to chloramine may be hindering the passivation of newer copper pipes, relative to older pipes in the distribution system that have been exposed to free chlorine. Some neighborhoods of newer homes have been noted to have persistent problems with blue water and blue staining due to high copper leaching. Finally, some recent plumbing codes suggest that it is desirable to disinfect premise plumbing systems using highly chlorinated waters adapted from AWWA mains disinfection procedures. Research on potential implications from this new practice is needed, as highly chlorinated water may be incompatible with many premise plumbing materials. Research Approach: The Project should be conducted in three phases the first two relate to laboratory or field investigations and the third phase concerns developing guidance for stakeholders. In the first laboratory phase, new building commissioning procedures should be researched to properly flush the plumbing with the goal of 1) preventing establishment of potentially adverse circumstances from flux and other constituents and 2) to assist in the formation of passivated scale on brass and copper tube. Testing should examine the effectiveness of flushing time on flux and debris removal in simulated premise plumbing rigs, with the goal of quantifying flush times and velocities necessary to remove deposits. The necessity and possible benefits of slow flushing to more rapidly passivate leaded brass in-situ and dissolve flux should be explicitly examined. At least 3 types of brass should be tested including those representative of Section 8 mechanical devices, brass in typical section 9 end-point devices (3% lead), and representative California proposition 65 brass which has met a more rigorous NSF 61 Section 9 leaching standard of 5 ppb (e.g., Prop 65-5 brass). Two types of flux including those compliant and non-compliant with B813 corrosive standards should also be tested. 53

60 A second phase of work should examine the potential benefits/detriments of pipe disinfection in new building construction. Specifically, some municipalities are instituting procedures associated with AWWA standards for main disinfection in new buildings, which expose premise plumbing to high ph solutions with 200 ppm free chlorine for 3 hours or a more dilute solution for 24 hours. This water with high chlorine can be highly aggressive to PEX, copper pipe and brass, and it is possible that this disinfection step could initiate problems with copper pitting or brass dezincification that could adversely affect pipe longevity and metals leaching. This phase of work should involve a literature review describing potential detriments of the procedure and bench-scale testing to quantify the potential magnitude of the adverse consequences. The product of the work will be practical guidance to minimize lead and copper corrosion problems arising from construction, flux use, and building commissioning procedures. The guidelines should help water utilities and others who direct contractors, plumbers, and construction managers. Included should be guidance on sampling for lead and copper (total and particulate species) and on applying the results of sampling and analyses. 54

61 REQUEST FOR PROPOSALS FORMATION, ACTIVITY AND SIGNIFICANCE OF ORGANOHALOAMINES Objective: The objective of this research is to investigate the formation, activity, and significance of organohaloamines in the distribution system. The method typically used for chloramine analysis does not differentiate between inorganic and organic chloramines, yet organic chloramines may not be as effective an oxidant, and may also be a source for the formation of other DBPs. This project will attempt to establish formation conditions, chemical properties, concentrations, composition and reactivity of organohaloamine compounds. The research will be based on a comprehensive understanding of the chemistry of haloamines, disinfection by-product formation associated with them, and other related topics, providing water utilities guidance on how to study the occurrence of organohaloamines in their specific systems. Recommended Budget: $350K Controversial Issues: Although extensive research has addressed the most prominent issues of chloramination and DBP formation, little information has been generated to date concerning organochloramines and virtually no information concerning organohaloamines beyond organochloramines. Without concrete knowledge concerning the properties and occurrence of these compounds, water practitioners and regulating agencies have little basis upon which to form science-based recommendations. As conceived at this workshop this project was to be a wide-ranging project aimed to address these deficiencies. However, those discussions did not take into account a recently funded AwwaRF project that will address at least some of the information needs concerning organochloramines. This project is AwwaRF project 4065 Organic Chloramines Formation in Water Distribution Systems. While project 4065 will not fully address the scope of work as originally conceived for this project, it will address much of the scope. The ongoing work in 4065 is progressing well, and so it may be preferable to wait for further development of knowledge from this existing project before engaging in further work on organochloramines or organohaloamines. 55

62 Background: Organic chloramines are an important issue for drinking water utilities because they interfere with N,N-diethyl-p-phenylenediamine (DPD) analysis of combined chorine residuals, and their ability to inactivate microorganisms or biofilms is questionable. Detection, stability and formation of organic chloramines are critical to understand chloramines decay and DBP formation. There is a need to accurately define and quantify organic chloramines, and to understand their biocidal efficacy. Organochloramines are produced through interactions of inorganic chloramines with organic compounds that are naturally present in drinking water or are introduced via treatment chemicals, leaching from biofilms, or leaching of pipe materials. Formation conditions, chemical properties, concentration levels, composition, and reactivity of such compounds remain largely unknown. Critically important parameters that need to be quantified include a) activity of organochloramines in redox reactions and disinfecting power associated with them; b) breakdown pathways and formation of unwanted disinfection by-products (e.g., NDMA, cyanogen chloride); c) correlations of organochloramine concentration and levels of organic nitrogen and/or total organic halogen (TOX); d) effects of water treatment on the formation of organochloramines; and e) their effects on the stability of corrosion scales and metal release. These same concerns and issues pertain to organohaloamines, a wider variety of possible DBPs than organochloramines. The objective of ongoing AwwaRF project 4065 Organic Chloramines Formation in Water Distribution Systems is to assess the significance of organic chloramines in the distribution system by investigating the reactions between free chlorine and monochloramine with biofilms, and focuses on the formation of organic chloramines and their associated biocidal efficacy. The project involves primarily laboratory work in bath experiments as well as use of a laboratory pipe loop system. Limited field work will also be performed at one drinking water utility. While this existing AwwaRF project is will not address all of the questions that revolve around organochloramines, it will provide major new information and understanding of organochloramine compounds. Research Approach: The research approach will include use of advanced methods to quantify the concentration of total organohaloamines and their specific classes (e.g., species associated with amine groups in NOM and/or treatment polymers) and will provide sampling/method SOPs and guidance for water utilities to conduct their own studies. Their structural identities will also be examined. Kinetic methods will be applied to quantify the formation and disappearance of organohaloamines and formation of target reaction products. The oxidative properties of organohaloamines will be quantified based on redox potential measurements at varying water chemistry parameters and potential effects (bacteriocidal and bacteriostatic) of organohaloamines on indicative microorganisms. The experimental data, as well as an inclusive review of relevant literature, will be presented and interpreted in a final report. 56

63 REQUEST FOR PROPOSALS MICROBIAL ECOLOGY OF PIPED WATER WITH RESPECT TO HEALTH RISKS Objective: Develop a broad-range ecological assessment of the microbiota within biofilms of distribution systems, and in premise plumbing, with the long-term goal of identifying normal/baseline community structures, which may provide insight into periods of system compromise. This assessment will address temporal and spatial trends for a range of water types expected across the United States. As part of this project, the project team will select and screen a limited suite of molecular tools for their usefulness in determining a fingerprint of the microbial ecology or functional processes of the bulk water and biofilms on surfaces. It is not intended that individual organisms will be identified, but rather that a representative, holistic view of the ecology be obtained. It will also be necessary to identify the approach that will be taken for collecting samples so that representative data will be obtained. Recommended Budget: $600K Controversial Issues: The project is considered speculative in that there is no industry precedent for this approach. There is a range of possible approaches and its success likelihood may not be known for some years. However, the general approach is based on current techniques used in microbial ecology and should provide a foundation leading to a major change in how the industry may assess health-related pathogen issues. Background: It has been well documented that only a small fraction of the microbiota from complex systems can be cultured (Amann et al., 1990; Amann et al., 1995; Manz et al., 1993; Muller et al., 1998; Zarda et al., 1997; Flood et al., 2000; Schwartz et al., 1998) and recently various direct sequencing approaches have become the preferred means to describing the microbial community of ecosystems. Initial approaches for distribution systems have focused on direct sequence analysis of 16S rdna clone libraries (Williams et al., 2004). Such work has demonstrated the 57

64 initial dominance of alpha-proteobacteria in distribution systems followed by beta-proteobacteria under different disinfectant residuals. An alternative to the phylogenetic approach is that of metabalomics, using largely unassembled sequence data obtained by shotgun sequencing of DNA or other approaches to isolate key metabolic-related genes from aquatic environments (Tringe et al., 2005). A key hypothesis to test here is whether systems contain baseline or normal fingerprints or environment-specific genes that change when the system has experienced a loss of physical integrity resulting in the introduction of organisms from the environment. If these changes can be detected via a difference in the fingerprint, it may provide an indication that the water has been subjected to an event that may have an impact on public health. If successful, this type of surveillance may supplant the need for monitoring for a wide range of potentially pathogenic organisms. A metagenomics approach (environmental sequencing) requires comparative sequence analysis for data interpretation that requires some baseline comparison of the different layers of complexity that are intrinsic to each sample. A consequence of this approach is the need for methods to normalize phylogenetic and functional diversity information, so as to avoid biases from incomplete data, different species dominance or genome sizes (Foerstner et al., 2006). Further, a standardization of data handling (bioinformatics) will also be required that may lead to a national database for describing the microbiota of water supply systems. Research Approach: Phase one of the project will include a screening of a selected group of currently available molecular tools for their usefulness in obtaining a fingerprint or metagenomic description of microbes/functional processes present in bulk water and distribution system biofilms. In addition, there will be a need to assess the best devices/reactors/samples that should be collected for assessments of appropriate water and biofilm samples. Further, under controlled conditions, the researchers should show that the fingerprint changes when the system s fingerprint has been perturbed by the addition of a range of specific (frank and opportunistic/indigenous) pathogens. Phase two of the project will bring forward the best approach(es) from phase one to demonstrate utility across a wide-range of water types in the US and their temporal changes. Overall the project team will 1) identify similarities and differences in microbial communities from distribution systems and premise plumbing across different water types in North America; 2) whether this (metagenomic) approach may have potential to identify if the system has been exposed to pathogens and the sensitivity in detecting these events. References: Amann, R.I., Binder, B.J., Olson, R.J., Chisholm, S.W., Devereux, R. & Stahl, D.A. (1990) Combination of 16S rrna-targeted oligonucleotide probes with flow cytometry for analyzing mixed microbial populations. Applied and Environmental Microbiology 56, Amann, R.I., Ludwig, W. & Schleifer, K.-H. (1995) Phylogenetic identification and in situ detection of individual microbial cells without cultivation. Microbiological Reviews 59(1),

65 Flood, J.A., Ashbolt, N.J. & Beatson, P.J. (2000) Simultaneous morphological and population analyses of environmental biofilms. In Investigation of Biofilms, pp Edited by H.-C. Flemming, T. Griebe & U. Szewzyk. Lancaster, PA: Technomic Publishers. Foerstner, K.U., von Mering, C. & Bork, P. (2006) Comparative analysis of environmental sequences: potential and challenges. Philosophical transactions of the Royal Society of London 361(1467), Manz, W., Szewzyk, U., Ericsson, P., Amann, R., Schleifer, K.-H. & Stenström, T.-A. (1993) In situ identification of bacteria in drinking water and adjoining biofilms by hybridization with 16S and 23S rrna-directed fluorescent oligonucleotide probes. Applied and Environmental Microbiology 59(7), Muller, M.R., Amann, R. & Schmid, E.N. (1998) Legionella-like slender rods multiplying within a strain of Acanthamoeba sp. isolated form drinking water. Parasitology Research 84(1), Schwartz, T., Kalmback, S., Hoffmann, S., Szewzyk, U. & Obst, U. (1998) PCR-based detection of mycobacteria in biofilms from a drinking water distribution system. Journal of Microbiological Methods 34(2), Tringe, S.G., von Mering, C., Kobayashi, A., Salamov, A.A., Chen, K., Chang, H.W., Podar, M., Short, J.M., Mathur, E.J., Detter, J.C., Bork, P., Hugenholtz, P. & Rubin, E.M. (2005) Comparative metagenomics of microbial communities. Science 308(5721), Williams, M.M., Domingo, J.W., Meckes, M.C., Kelty, C.A. & Rochon, H.S. (2004) Phylogenetic diversity of drinking water bacteria in a distribution system simulator. Journal of Applied Microbiology 96(5), Zarda, B., Hahn, D., Chatzinotas, A., Schönhuber, W., Neef, A., Amann, R.I. & Zeyer, J. (1997) Analysis of bacterial community structure in bulk soil by in situ hybridization. Archives of Microbiology 168(3),

66 REQUEST FOR PROPOSALS DEVELOPMENT OF MULTIPLE INDICATORS OF DISTRIBUTION SYSTEM MICROBIAL INTEGRITY Objective: As the total coliform rule is revised there will remain significant concerns over the usefulness and meaning of indicators of distribution system water quality. This project will evaluate current and emerging indicators of the microbial conditions in distribution systems and of distribution system integrity. The project will evaluate the application of multiple indicators including biological and chemical indicators. Recommended Budget: $400K Controversial issues: The water industry has been sampling for total coliform for many years. Many utilities have very few positive results over a long period of time and therefore they value the total coliform rule and total coliform as an indicator. Controversy has developed as a result of the inconsistency of the various EPA approved methodologies that give disparate results for the presence or absence of Total Coliforms. Some utilities have addressed their violations by changing the method that they use to test for total coliform. Although the work contemplated in this project is important, and could prove very illuminating, it will not be sufficient to effect a major change in the current Total Coliform Rule (TCR) regulatory structure. Further work, including considerably more research spending, would be needed before a major change in the TCR would take place. However, if new indicators or analyses are found that are useful for management of a water distribution system, and have major advantages over current TCR requirements, these indicators and analyses would be valuable to utilities and might enter general use even if the TCR remained unchanged. Background: In the 1987 proposed Total Coliform Rule (EPA 1987) the objectives of the total coliform rule are stated as 1) evaluate the effectiveness of treatment, 2) determine the integrity of the distribution system, and 3) predict the presence of fecal contamination. In the same paragraph as 60

67 these objectives, EPA acknowledges that while total coliforms are not pathogenic the presence of total coliform is believed to be indicative of potential presence of fecal pathogens. This assertion is disputed by many microbiologists that believe total coliform is not a good indicator, as it may not meet the key objectives stated above. In addition, low incidence, high variability, and inconsistent methods and small sample sizes lead to significant difficulties in using total coliform as a reliable indicator of effective treatment, integrity of the distribution system, and presence of fecal pathogens. Utilities in the U.S. are currently spending in excess of $100,000,000 to meet the sampling requirements of the Total Coliform Rule. This project will evaluate alternatives to determine whether the extensive resources currently being expended could be more effectively used with a better indicator that would be useful in advising the condition of the distribution systems and the effects of mitigation efforts following contamination events. The topic of the use of total coliforms as an indicator of water quality concerns is addressed in detail in an Issue Paper associated with the ongoing Total Coliform Rule discussions. This paper was prepared in January 2007 by the AWWA, and is available on the USEPA website at: Also there are two relevant AwwaRF projects that should be reviewed. AwwaRF Project 3116 Strategy to Manage and Respond to Total Coliforms and E. coli in the Distribution System will develop a practical guide to help utilities manage microbial water quality and develop response strategies to total coliforms and E. coli events in the distribution system. It will also include the application of available microbial source tracking tool(s) for the determination of contamination source(s) in the distribution system. AwwaRF Project 4024: Significance of Current Methods and Monitoring Strategies for E. coli and Total Coliform Measurements will evaluate current methods, particularly the impact of sample volume and frequency, to assess practical implications for both E. coli and total coliform measurements. Research Approach: The researcher shall conduct a literature review of potential and existing indicators used in various contexts (food, health, and drinking water in North America and internationally) and other related monitoring programs. The researcher will evaluate the alternative indicators and their potential usefulness to meet the stated goals of the TCR or of utility needs for distribution system monitoring. Reference will be made to sources and causes of loss in distribution system integrity as found in the 2006 NAS report, Drinking Water Distribution Systems- Assessing and Reducing Risks. The researcher will evaluate the multiple indicators and their potential usefulness in combination for evaluating distribution system integrity for the control of microbial risk. The researchers will choose at least six indicators and in laboratory or pilot systems evaluate the characteristics of the indicators for assessing microbial conditions in the distribution system. Again these indicators should be linked to sources and causes of risk in the distribution system as laid out in the 2006 National Academy of Sciences Report Drinking Water Distribution Systems: Assessing and Reducing Risks. Finally, actual applications in at least three water distribution systems will be demonstrated to show how to sample and how to apply sampling results for these indicators. 61

68 References: NRC Drinking Water Distribution Systems: Assessing and Reducing Risks. Washington, DC: National Academies Press. USEPA Proposed Total Coliform Rule. Federal Register, Vol 52, No. 212, Tuesday Nov 3, USEPA A Review of Distribution System Monitoring Strategies under the Total Coliform Rule. USEPA Office of Water, Office of Ground Water and Drinking Water, Total Coliform Rule Issue Paper prepared by the American Water Works Association. 62

69 REQUEST FOR PROPOSALS CHARACTERIZING THE COMPONENTS OF THE MICROBIAL COMMUNITY RESPONSIBLE FOR NITRIFICATION Objective: The objective of this study is to identify the microorganisms in distribution systems and premise plumbing that are responsible for nitrification. There is a lack of understanding of the diversity of organisms that nitrify and their activities in finished water. Determining what organisms are involved will allow for better detection and quantification methods, and may also provide insights into monitoring and control methods to help prevent, or minimize the impacts of, a nitrification episode. Recommended Budget: $250K Controversial Issues: Much work has been done on trying to prevent nitrification episodes, and many references can be found on this topic. This project differs from previous work in that it will attempt to identify appropriate monitoring that might indicate an impending nitrification episode, as well as identify methods to recover from a nitrification episode. In particular, it would be valuable to identify methods to recover from a nitrification episode without resorting to the use of free chlorine. These specific topics are largely unaddressed in previous work. Background: With the changes in the D-DBP Rule, it is increasingly more difficult - even prohibitive - for drinking water utilities to use periodic free chlorination to resolve nitrification issues. Consequently, there is a critical need for chloraminated systems to develop strategies for resolving nitrification episodes. One approach is to develop better early warning systems for the onset of nitrification. A mechanism for accomplishing this would be to have more sensitive and rapid detection methods for the presence of nitrifying bacteria. However, there is an incomplete understanding of the types of organisms involved in nitrification in distribution systems, which necessitates an approach that encompasses a diversity of organisms that contribute to the process. 63

70 Nitrification is carried out by at least two distinct groups of bacteria: ammonia-oxidizing bacteria (AOB) are responsible for the oxidation of ammonia to nitrite, which is subsequently converted to nitrate by nitrite-oxidizing bacteria (NOB). Most nitrifiers are obligate chemolithotrophs, with the exception of the Nitrobacter species, which consists of facultative chemolithotroph microorganisms. Also, they are generally autotrophic, but some can grow mixotrophically. It is also possible that there are heterotrophic nitrifiers in distribution systems, but this is yet to be proven. The autotrophic nitrifiers were originally classified in the family Nitrobacteraceae, but have been reclassified based on 16S rrna analysis in four separate subdivisions of the Proteobacteria division (α, β, γ and δ), as well as other classes. AOB have been separated in five genera: Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosovibrio, and Nitrosolobus. More recently, the taxonomy of nitrifiers was re-assessed using sequence similarities of their 16S rdna. As such, most chemolithotrophic AOB (and all AOB characterized in freshwater) now belong to the β-subdivision of the class Proteobacteria, which comprises the genera Nitrosomonas and Nitrosospira (which formerly included strains of Nitrosolobus, Nitrosovibrio and Nitrosospira itself). The diversity of AOB in the β-subclass Proteobacteria has been further differentiated into seven clusters based on 16S rdna sequence relationships. Other groupings have also been suggested by subsequent researchers, and it is likely that AOB classification will be revisited in the future. Historically, Nitrosomonas has been the most frequently mentioned genus associated with the first step of the nitrification process (i.e., oxidation of ammonia into nitrite) in drinking water, wastewater and seawater. However, Feben (1935) isolated Nitrosococcus species from filter beds and tap water samples collected from a chloraminated system. A recent study using molecular methods suggest that Nitrosospira types are the most common AOB in soils and freshwater, and not Nitrosomonas types as was previously thought using culturing techniques. However Regan et al. (2003, 2004) (who also used molecular techniques) observed that Nitrosomonas (and particularly strains from the Nitrosomonas oligotropha cluster) appear to be ubiquitous in fullscale drinking water distribution systems receiving chloraminated water, and Nitrosospira seem to be constituting a negligible fraction of the AOB community. Similarly Regan et al. (2002) observed the presence of Nitrosomonas oligotropha and Nitrosomonas ureae in pilot-scale chloraminated drinking water distribution systems, with a considerably smaller presence of Nitrosospira-like AOB. NOB, are in various subdivisions of the class Proteobacteria. Nitrobacter (includes also Nitrocystis) is the most frequently mentioned genus associated with this second step of the nitrification process (i.e., oxidation of nitrite into nitrate), although other genera, including Nitrospina, Nitrococcus, and Nitrospira can also oxidize nitrite to nitrate, particularly in marine environments. Nitrobacter form a tight cluster within the α-subclass of Proteobacteria, whereas Nitrospina are loosely related to the δ-subclass. Nitrococcus mobilis is a member of the γ- subclass, whereas Nitrospira constitute their own phylum in the Bacteria domain. Hovanec et al.(1998) observed that Nitrobacter winogradskyi was not the dominant NOB isolated from freshwater using molecular methods, but Nitrospira moscoviensis and Nitrospira marina appeared to be the dominant species. Regan and colleagues (2003) (who also used 64

71 molecular techniques) observed that Nitrospira (and particularly Nitrospira moscoviensis) were detected in most of the samples collected from full-scale chloraminated drinking water distribution systems, while Nitrobacter were detected in a few samples only. Similarly, Regan et al. (2002) observed that the NOB communities of pilot-scale drinking water distribution systems were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. In addition the AwwaRF Project 3088 Identification of Heterotrophic Bacteria That Colonize Chloraminated Drinking Water Distribution Systems will identify and quantify the heterotrophic bacteria that colonize chloraminated drinking water distribution systems. It will determine whether bench- and pilot-scale chloraminated systems are adequate models to study the type of bacteria that colonize full-scale systems. It will also formulate mechanisms and hypotheses for the role of these bacteria as the critical microbial group in nitrification of chloraminated distribution systems. Research Approach: This research would be conducted in two phases. The first phase of research will focus on methods development suitable for identification of the nitrifiers. The researcher would need to employ molecular and culturing methods that will target different types of nitrifiers that exist in the bulk fluid and on the surfaces of pipes/plumbing. Emphasis should span both ammonia oxidizers and nitrite oxidizers. The second phase of research would focus on testing the methods developed on environmental samples from a variety of distribution and plumbing systems where nitrification is taking place. If possible, these methods should provide more than presence/absence data and instead give quantitative or semi-quantitative information on nitrifiers and provide understanding of the evolution of nitrification events. Once research is completed, the researcher should document in the final report the methods developed, and their application, so that other utilities and researchers could conduct similar studies. The researcher should also analyze all data from Phase 1 and 2 and evaluate possible monitoring and control strategies to minimize the occurrence of, or impact from, nitrification events. References: Feben, D. (1935). Nitrifying bacteria in water supplies. J. Amer. Water Works Assoc. 27(4):439. Hovanec, T.A., L.T. Taylor, A. Blakis, and E.F. Delong. (1998). Nitrospira-Like bacteria associated with nitrite oxidation in freshwater aquaria. Appl. Environ. Microbiol. 64(1): Regan, J.M., G.W. Harrington, and D.R. Noguera. (2002). Ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system. Appl. Environ. Microbiol. 68(1): Regan, J.M., G.W. Harrington, H. Baribeau, R. De Leon, and D.R. Noguera. (2003). Diversity of 65

72 nitrifying bacteria in full-scale chloraminated distribution systems. Water Res. 37(1): Regan, J.M., A-H Cho, S. Kim and C.D. Smith. (2004) Monitoring Ammonia-Oxidizing Bacteri in Chloraminated Distribution Systems. AwwaRF, Denver, CO. 66

73 REQUEST FOR PROPOSALS WATER INDUSTRY CONTRIBUTION TO EPIDEMIOLOGICAL STUDIES INVOLVING DISTRIBUTION SYSTEM WATER QUALITY Objective: The objective of this research is to provide guidance in the interpretation of the data to public health professionals engaged in exposure or epidemiologic studies involving drinking water in distribution systems. Such guidance is intended to minimize confounding, biases and errors in these studies. Recommended Budget: $120K Controversial Issues: The intent here is not to influence the objectives of exposure or epidemiological studies but to enhance their design and success. Environmental scientists, engineers and operators can make important contributions to studies conducted by health professionals, since failure to follow accepted methodologies, or generate certain data, can jeopardize the results and usefulness of exposure and epidemiological studies. However, care must also be exercised so as not to compromise the integrity of such studies. The USEPA and others are considering epidemiological and health impacts studies in relation to the Total Coliform Rule (TCR) and the Distribution System Rule (DSR). The researchers involved in this proposed project should be knowledgeable of at least some of the details of the proposed and/or ongoing epidemiological and health effects work in order to focus efforts on useful products to the extent possible. These links to the epidemiological and health effects research should be provided by either AwwaRF staff, or the DSWQ SI Expert Panel. Finally, AwwaRF does not fund epidemiological studies and this work should not be interpreted as leading in that direction. 67

74 Background: The extent to which customer health is adversely affected by distribution system and premise plumbing failures is not completely understood. There is a critical data gap on the potential for well-operated distribution systems to contribute to endemic waterborne diseases. Epidemiological studies have been conducted worldwide to estimate the contribution of endemic disease due to failures in public distribution systems. In general, epidemiologist and environmental scientists conducting these studies are not drinking water practitioners and therefore may miss important data or misinterpret water utility data. Input from drinking water professionals is likely to aid in the minimization of errors in this type of study. One approach is to summarize the types of information that are available (e.g., water pressure, total chlorine residual, total coliform test results, customer complaints records, water main break, leak detection records, etc.) and how to use and interpret that information for inclusion in epidemiological studies. The water industry needs to be more involved in the data gathering, analysis, and review in such studies. Research Approach: The audience for this report is considered to be the epidemiological and health effects researchers working on potable water concerns. A group of experts will compile a report for the use by epidemiological and public health experts as they design and implement studies related to potable water distribution systems. The report should include some brief background information on what constitutes typical distribution system design and operation in the United States (addressing such issues as branching of flow, water age, multiple treatment plants and inputs to the distribution system, fire flow requirements, and distribution system construction materials). These typical design and operational approaches should also be compared and contrasted with some of the more common alternative approaches, especially those involving no residual disinfectant, such as in the Netherlands, but the primary focus should be the situation (regulations and typical distribution design and operation) in the United States. There should also be a summary of terminology that may help public health experts better understand distribution systems, addressing such things as hydrant flushing, leak detection, asset management, total coliforms, etc. The report should also include implications of the data related elements listed below in terms of how each element can influence the results of a public health study. Similarly, the report will include sources of information and data for potable water systems, with an emphasis on understanding the general quality and availability of those data Commonly available water supply data Commonly available water quality data Commonly available distribution system operational data Ability or limitations inherent in collecting additional data General overview of data collection costs Data available for premise plumbing 68

75 With regards to the data related elements identified above, the intent is not to create a database, but rather to describe the types of data typically available, as well as typical format and access. The quality discussion of the data should address whether the data are of generally high, medium, or low quality. For instance, utility data on positive total coliform tests should typically be high quality, but data on the occurrence of a backflow event would be low quality (in most cases). The following sources of the above types of data should be specifically addressed in the data discussion: a. Data that are required to be reported to regulatory agencies under certification as to its truthfulness and accuracy, and how these data can be accessed at those agencies. For instance, State primacy agency records of SDWA compliance data can typically be accessed under FOIA-equivalent state rules, as can EPA SDWA compliance data, etc. In particular, thought should be given to how to obtain electronic files of those data for further evaluation and manipulation. b. Identification of non-regulatory databases which might be useful for some purposes. For instance, USEPA Storet, USGS source water information, etc. c. Identification of the types of data utilities normally have on-hand but do not report, with some suggestions on how to access these data. d. Some discussion of what is included in WaterStats from AWWA which is aggregated high level data from a few hundred utilities and is available on CD. The report should also include examples of issues resulting from lack of data or misuse of data from past epidemiological studies and how to avoid future issues. 69

76 REQUEST FOR PROPOSALS EFFECTS OF DISINFECTANTS, NATURAL ORGANIC MATTER AND OTHER WATER QUALITY PARAMETERS ON THE INTERNAL CORROSION OF IRON PIPE AND STABILITY OF SURFACE SCALES Objective: This study will generate experimental results to further understanding of the extent and implications of the effects of water quality on iron corrosion and iron corrosion scale stability. It is anticipated that these results will help water utilities and drinking water professionals better manage iron corrosion, scale dissolution, water quality aesthetics (turbidity and color), and the general transport and accumulation of contaminants in the distribution system. Recommended Budget: $500K Controversial Issues: Scales formed on the surfaces of iron-containing materials exhibit a diversity of morphologies, compositions, and mobilities. These properties, as well as the overall corrosion rates, are affected by several water quality parameters, notably ph, alkalinity and disinfectant residual. Evidence related to the Washington DC lead experience strongly suggests that chloramination conversion for DBP control can adversely impact the stability of lead corrosion scales. In a similar sense, a review of iron electrochemistry and solubility suggest that DBP control practices may also influence stability of iron corrosion scales, possibly leading to dissolution and contaminant release issues (Schock, 2004). Background: The role of inorganic water chemistry parameters in the corrosion of iron in drinking water is reasonably well understood, but that of natural organic matter remains entirely unexplored. This is in contrast with the well-established fact that NOM exhibits prominent activity towards surfaces of iron minerals, affecting many of their properties. NOM can also accelerate the reduction of ferric oxyhydroxides and affect the growth and stability of biofilms. Each of these processes has significant implication for the understanding of the mechanisms of iron corrosion in drinking water systems and strategies to control it. 70

77 The corrosion of iron pipe and stability of surface scales formed on its surface are critically important for long-term reliability of drinking water distribution networks, prevention of red water episodes, and suppressing biofilm growth. Although extensive research concerned with some of these issues has been carried out, important issues related to current and future practices of water utilities remain (Benjamin et al, 1996). For instance, the transition from chlorine to chloramines mentioned above is likely to be accompanied by a decrease of redox potential and, potentially, ensuing destabilization of surface scales. Effects of natural organic matter (NOM) on the corrosion of iron have not been adequately studied, although prior research indicates that NOM strongly affects the growth of copper- and lead-containing solid phases, their colloidal mobilization, and leaching (Korshin et al, 1996; Korshin et al, 1999; Korshin et al, 2000). Research Approach: This research approach should utilize appropriate experimental methods (electrochemical and other) to quantify rates of corrosion, metal release, and consumption of oxidants. Moreover, the morphological, structural, and colloidal properties of iron-containing solids, as well as their redox activity in the presence of varying levels of chlorine, chloramines, NOM, and varying water chemistry indicators (ph, alkalinity, silicate and phosphate concentrations) should be quantified using appropriate structure-sensitive methods. Efforts to examine the growth of biofilms and/or incorporation of organic carbon into the scales are also needed. Furthermore impact on old versus unexposed new pipes should be assessed. Some specific research questions to be addressed include: What is the relationship between background levels of NOM and incorporation of target contaminants into iron corrosion scales? Which forms of NOM are most problematic in terms of corrosion scale stability? What is the most effective way to characterize the stability of iron based corrosion scales? What physical mechanisms cause the corrosion solids per se to become physically unstable and susceptible to mobilization and resuspension into the aqueous phase? References: Schock, Michael R Distribution Systems as Reservoirs and Reactors for Inorganic Contaminants. DRAFT. US Environmental Protection Agency. Cincinnati, OH. Korshin, G.V., Ferguson, J.F., and Perry, S Influence of natural organic matter on corrosion of copper in potable waters. Journal of American Water Works Association, 88 (7): Korshin, G.V., Ferguson, J., Lancaster, A., and Hao Wu Corrosion and Metal Release from Lead-Containing Materials: Influence of Natural Organic Matter and Corrosion Mitigation. AwwaRF. Denver, CO. Korshin, G.V., Ferguson, J., and Lancaster, A Influence of natural organic matter on the corrosion of leaded brass in potable water. Corrosion Science, 42 (1): 53-66). 71

78 Benjamin, Mark M., Heinrich Sontheimer, and Pierre Leroy (2 nd Ed.). Corrosion of Iron and Steel. Ch. 2 in Internal Corrosion of Water Distribution Systems. AwwaRF and DVGW- TZW: Denver, Colorado. Schock, Michael R., Wagner, I., and Oliphant, RJ The Corrosion and Solubility of Lead in Drinking Water. In: Internal Corrosion of Water Distribution Systems. AwwaRF and TZW: Denver, Colorado., p

79 REQUEST FOR PROPOSALS PROJECT TITLE DEVELOPMENT OF PREDICTIVE MODELS FOR THE FORMATION AND FATE OF REGULATORY DBPS IN DISTRIBUTION SYSTEMS Objectives: The objective of this study is to develop predictive models to assess the fate of DBPs of potential health concerns in the distribution system. This project will apply the understanding of processes forming and degrading important DBPs, and develop qualitative and quantitative models capable of predicting the influence of key water quality and distribution system characteristics on DBPs. This project will also address the effect of various management strategies, so that water utilities can apply Initial Distribution System Evaluation (IDSE) and other data to better predict and plan for Stage 2 compliance in controlling location-specific DBP occurrences. Budget Estimate: $400K Controversial Issues: While the creation of predictive models for DBPs in the distribution system is clearly a critical concern, much work has been completed, and other very relevant work is ongoing at this time. Some of this work, relatively recent, has even focused on models of DBP formation and decay. While the need for predictive models is high, work is ongoing to understand basic fundamental processes that influence the formation and decay of DBPs in the distribution system, and this understanding, once gained, could be an underpinning of any predictive models in this area. Thus, it may be most appropriate to delay further predictive model work pending results from AwwaRF Projects 2990 and 3122, in particular. Background: Processes occur that form and degrade DBPs in distribution systems. These may largely determine concentrations at the tap for some DBPs. Reductive loss of some DBPs from reactions with deposit materials has been demonstrated. Less is known about potential surface influences on the formation of DBPs. A need exists for improved understanding of all processes involved 73

80 and their relationship to system characteristics, and for models that can provide guidance in their management. The IDSE will generate a lot of system-specific DBP data that can be used with system specific characteristics (such as pipe materials and hydraulics) to better model the fate and formation of DBPs. The researchers should be familiar with several projects funded by AwwaRF that deal with formation and degradation of DBPs in the distribution system. Key projects among them are AwwaRF Projects 2990 and The former, Abiotic Degradation of DBPs in Distribution Systems investigates the role of pipes in the degradation of DBPs. The main goal of this project was to evaluate the potential of DBPs to be degraded in cast or ductile iron mains. The project confirmed that abiotic DBP degradation occurs in distribution systems and that degradation of HAAs in pipe reactors proceeds rapidly via dehalogenation. The DBP degradation kinetics developed can be used to predict degradation in pipes. The draft final report for this project is due in late AwwaRF Project 3122 Degradation of HAAs in Distribution Systems is an ongoing project that involves a detailed investigation of kinetics of HAA biodegradation, identification of degraders and their prevalence in the distribution system. The project will study degradation kinetic models that can be used to develop predictive tools. There are additional AwwaRF projects that are relevant to this issue. Project 2649, Disinfectant Decay and Corrosion: Laboratory and Field Studies (2004), investigated the influence of corrosion on chlorine residuals in two distribution networks. It measured electrochemical current noise and relates this to corrosion rate. It established the extent of data collection needed to use commercial distribution system models confidently, and identified typical parameter values for use with these models. Project 2685, Assessment of Chloramine and Chlorine Residual Decay in the Distribution System (2006), investigated the factors that contribute to chlorine and chloramine decay in the distribution system following advanced treatment processes. Project 2865, Predictive Models for Water Quality in Distribution Systems (2004), characterized the state of quantitative distribution system water quality models and identified critical research needs. Project 2770, Formation and Decay of Disinfection By-Products in the Distribution System, investigates the formation and decay of DBPs in the distribution system by evaluating factors that affect DBP behavior, such as mixing of different waters, loss of chlorine residual, pipe wall and sediment interaction, and biological reactions. Research Approach: The ultimate goal of this project is to advance predictive modeling capabilities as well as our understanding of the fundamental processes that occur in distribution systems regarding DBPs. The project approach should have the following tasks. Evaluate the formation of regulated DBPs (TTHMs and HAA5) considering processes that form them and processes that may degrade them in the distribution system Include the role of water phase and the pipe-water interface in contributing to the formation and loss of DBPs 74

81 Include abiotic and biological roles Include the influence of distribution system characteristics Use IDSE or similar data from real systems to assist in these various evaluations Develop predictive models that can be used to predict location-specific DBP levels in distribution systems. 75

82 REQUEST FOR PROPOSALS OCCURRENCE STUDY OF WATER QUALITY CHANGES IN PREMISE PLUMBING Objective: The objective of this project is to characterize the types of water quality changes that occur in premise plumbing, separate from cross connections and backflow events. The project approach should be based on a research framework that provides a comprehensive examination of several related water quality issues physical, chemical, and microbiological water quality changes. Identification of issues should include various components of the customer plumbing system, the materials employed, and the operation of the plumbing that play a major role in water quality changes. The water quality changes of interest will be focused on those with potential for health risk concern and/or regulatory violation, as well as aesthetic issues such as red water. The research framework will provide a needed structure for research related to water quality concerns within customer plumbing systems. Recommended Budget: $450K Controversial Issues: The water quality control of utilities typically ends at the water main connection or the service line near the edge of the customer property. Investigations and information concerning water quality changes on private property may be viewed by some as crossing the boundary of utility responsibility. This effort may uncover issues that affect customers where the water utility may have no control, yet the public and media may not understand or accept that. Background: Utilities are required to examine water quality at the tap despite the fact that utility ownership of the pipe system typically stops short of this sampling point (the tap). The 2006 NAS report Drinking Water Distribution Systems: Assessing and Reducing Risks, addressed premise plumbing as an important issue for water quality and risk for customers associated with drinking water distribution systems. Also, and the Centers for Disease Control have recently made the 76

83 distinction between the "distribution system" and plumbing, or water not under the control of the water system, and have implicated plumbing systems as causes of waterborne disease outbreaks. Also, utility case studies have suggested water quality changes within the customer plumbing, although these have generally been published in relation to broader issues. The separation of ownership of piping creates a knowledge gap in water quality changes. This lack of knowledge is compounded by the customer s own lack of information concerning water quality effects of pipe material, layout, and operation. Overall, a coordinated, systematic study of how water quality can change in premise plumbing has not yet been conducted. A fundamental starting point that identifies the multi-faceted and inter-related issues surrounding customer plumbing is needed to organize supporting research. The resulting research will increase the water industry knowledge in this area. This knowledge can then be converted into a guide for the customer to facilitate further improvement of water quality in the customer plumbing, or used by the utility to help positively influence water quality in premise plumbing through the characteristics of the water supplied to the customer. This work must address the various premise types (residential, business, hospital, school, etc.), plumbing designs (storage, wet fire systems, hot water and cold water, etc.), and habits of water use (weekend stagnancy, high demands during spikes in occupancy, etc.). One outcome would be a survey or study of actual water quality changes. Another outcome would be recommendations on how, when, and what to sample for water quality changes. AwwaRF studies that should be considered in this project include the following projects: AwwaRF Project 241, Residential, Commercial, and Institutional End Uses of Water, provides specific data on the end uses of water in residential, commercial, and institutional settings across the United States. It includes data on disaggregated indoor and outdoor uses, which can be used to improve engineering estimates of residential, commercial, and institutional water consumption. The residential portion of this study was published as: Residential End Uses of Water in 1999 (Order 90781), and the non-residential was published as Commercial and Institutional End Uses of Water in 2000 (Order 90806). AwwaRF Project 2611, Impacts of Cross-Connections in North American Water Supplies (2003), documented the occurrence of cross-connections in utility distribution and premise piping systems, and estimates the extent to which they are abated. It assessed both active abatement programs on premises and containment-only programs. Also it identified key criteria to assist with the successful implementation of an effective assessment program and to address consumer complaints. AwwaRF Project 3008, Susceptibility of Distribution Systems to Negative Pressure Transients (2006), performed hydraulic surge modeling on a variety of distribution systems. It determined the characteristics that make systems vulnerable to negative pressure transients. It tested common scenarios to develop a vulnerability ranking, evaluate mitigation approaches, and developed guidance for selecting optimum monitoring locations. 77

84 AwwaRF Project 3022, Cross-Connection and Backflow Vulnerability: Monitoring and Detection, will investigate the most effective technologies available, as well as recommended placement, to prevent, monitor and rapidly detect contamination in the distribution system related to cross-connection and backflow events. AwwaRF Project 4152, Managing Distribution System Pressures to Protect Water Quality, will investigate the extent to which water utilities manage pressure in an effort to protect water quality, determine if distribution system locations maintained at low pressure have poorer water quality than other distribution system locations, determine the daily and annual risk of infection caused by temporary low pressure, and recommend best management practices for distribution system locations that may experience low pressure. Research Approach: The project would begin with a workshop to identify the required elements of any premise plumbing water quality study and future customer guidance documents, including: Identification of water quality issues related to material selection to include relevant reports of waterborne disease by the CDC. This would outline changes in chemical composition and biological makeup of drinking water from the water main to the tap as related to specific pipe materials. Identification of potential water quality changes within customer premise plumbing elements under varying use patterns. This would contain specific information about elements such as hot water heaters, sprinkler systems, bypasses, pressure reducing valves, water recirculation systems, and backflow preventers. Layout of the terminology used to describe plumbing components of interest to this work. Identification of the many types of premises and how to categorize them for water quality issues (e.g., schools vs. hospitals vs. homes vs. high rise buildings). The ensuing discussion will focus on both the various components of customer service plumbing and the identifiable water quality characteristics that can be adversely changed by the plumbing. Individuals with knowledge in building plumbing construction should participate in the workshop as well as utilities interested in this issue. The project will rely on significant input from utilities interested in the affects of premise plumbing on water quality. The utilities, in cooperation with building owners, will provide sites of interest, existing data and access for further data collection and analysis. Steps in this investigation process may include: Researcher will select representative study sites across various systems with differing water quality to cover: Various premise types Various plumbing designs and materials Various habits of water use Researcher will sample and identify water quality changes in the above study sites (regulatory and non-regulatory) 78

85 Researcher will recommend (with input from the PAC) how additional research or utilitybased studies can follow up on this work (how, when, what to determine if water quality changes are occurring in a premise s plumbing) Researcher will address the impacts on customers use of water on the changes in water quality Researcher will identify existing means and technologies to mitigate or prevent such changes Researcher will address the impacts of chemical contamination (except from a backflow or cross-connection event) on immediate and longer-term water quality in premise plumbing. For example, how might contamination move through a hot water system differently than a cold water system; or how a chemical s fate might be affected by different plumbing materials. A final report summarizing the findings will be developed. It will also include a review of identified mitigation measures that have been attempted or implemented and the degree of success of the various measures. 79

86 REQUEST FOR PROPOSALS DEVELOPING EXPOSURE ESTIMATES OF THE CONTRIBUTION ON DRINKING WATER TO BLOOD LEAD LEVELS USING REALISTIC INTEGRATED WATER LEVELS Objective: The objective of this research is to develop monitoring strategies for lead in drinking water that can be used to assess lead exposure by individuals. These monitoring strategies will then be applied to a few systems to determine consumption profiles for various subgroups that can be used in conjunction with the EPA/CDC lead uptake model to develop estimates of the contribution of drinking water to blood levels for different sub-populations. Estimated Budget: $250K (Potential to leverage CDC funds) Controversial Issues: The issue of the LCR monitoring protocol not representing individual exposures to lead, but rather representing whether or not a utility has implemented and maintained optimized corrosion control, is very challenging for utilities. The current monitoring strategy may not accurately assess individual exposure to lead throughout a day of drinking water use. Utilities struggle with the LCR monitoring protocol. If the results of this study showed considerable variation from the data collected under the LCR, these data could be perceived negatively or used by groups desiring tighter standards, regardless of the results. Nonetheless, this project could provide valuable information if other epidemiological or health effects studies were anticipated by the USEPA or others, or if the water community wanted to have a major focus on developing the best possible data on lead exposure. Background: Previous measures of lead exposure have typically relied upon lead values obtained through the EPA s Lead and Copper Rule (LCR) monitoring protocol. This protocol was not developed to assess individual exposures, rather it was developed to determine whether a utility has implemented and maintained optimal corrosion control treatment. The LCR protocol relies upon first draw lead concentrations after the water had been sitting in the pipes for at least 6 hours 80

87 without use. This first draw sample may approximate the lead concentration in the first liter of water that is used in a day, but the exposure in subsequent aliquots of water may be significantly different. As a result, health effects studies using the protocol have not accurately captured exposure to lead by an individual or an aggregate population. In order to accurately assess the exposure, a different water monitoring strategy is needed that captures the variability of lead concentrations throughout the day. Miranda et al. (2006) attributed increases in children s blood lead levels to age of dwelling and type of disinfectant used by the public water system. Research Approach: The research team should develop a water lead sampling protocol that can be used to characterize the average daily exposure by individuals. The team should also look at exposure by the most susceptible sub-populations and assess whether a different monitoring protocol is necessary to cover their exposure. The project should develop the protocol and use the protocol to measure the exposure by some pilot populations. The project should also compare actual exposure (which considers variability in water consumption patterns in various populations) with exposure estimated in the Lead and Copper Rule. After the protocol is established, the research team should identify a few systems with varying profiles using current LCR sampling data. The team will then identify comparison sites within each system and employ the protocol to estimate exposure at those locations. The team should select consumption profiles for various sub-groups of interest and model the lead uptake. The project should also determine whether the findings of Miranda et al. (2006) are reproducible in other geographic areas. References Miranda, M.L., Kim D., Hull, A.P., Paul, C.J. Overstreet Galeano M.A. (2006) Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems. Environmental Health Perspectives. doi: /ehp

88 REQUEST FOR PROPOSALS IDENTIFICATION OF RESEARCH GAPS IN DEFINING BIOLOGICAL STABILITY OF WATER IN NORTH AMERICAN DISTRIBUTION SYSTEMS Objective: The objective of this project, which the first of a three stage project, is to perform a comprehensive review of research that has been completed abroad and in the United States on biological stability of water in distribution systems, with emphasis on the experiences gained in North American systems. This project will provide insight on what research still needs to be performed to provide US systems with the information they need to adequately design, implement, operate, and monitor water treatment plants to produce biologically stable water that would persist throughout the distribution system. Another component of this project will be to identify factors in the distribution system that support the growth of microorganisms and therefore contribute to the degradation of water quality. Recommended Budget: $200K Controversial Issues: There has been a considerable amount of research already completed on assessing biological stability and the design of biological treatment in Europe, where minimal or no secondary disinfectant concentrations are used. Most existing U.S. systems are limited to single stage filtration as opposed to the European model of two stage filtration, essentially having a separate filter for biological treatment. Partly due to these differences, the information from Europe may not be directly applicable to US systems. Furthermore, the available information does not provide a quantitative assessment of the costs and benefits of biological stability versus secondary disinfection (as commonly practiced in North America). Although the scope of this proposed project is broader in concept than AwwaRF Project 4129, Assessment of Operating Conditions for Biological Filters in Drinking Water Treatment, Project 4129 (scheduled for completion in 2008) should provide considerable value to any work focused on biological stability of water in distributions systems. It is suggested that this proposed project be coordinated with activities in 4129, and that these two projects should be considered as a continuum of projects to advance biological filtration and production of biologically stable water in North America. 82

89 Background: Biologically stable water can be defined as water that does not change with respect to microbiological growth or decay as it travels through the distribution system. The goal of treatment can be to produce water that is not likely to support bacterial growth (biofilms) in distribution systems and premise plumbing. European systems have been designed to produce biologically stable water in the absence of a secondary disinfectant, which is contrary to common practice in the U.S. In addition, the measurement methods available to assess biological stability are often expensive and cumbersome. If the concept of producing biologically stable water is to gain acceptance in the US, it is necessary to adopt existing information from the experiences of other countries and the US into practical guidelines for operating treatment plants to produce this high quality water and also to identify areas where critical impediments to implementation of these practices exist. In addition, there is reluctance in the US to use biological treatment methods in the production of potable water due to concerns regarding possible carry-through of pathogens into the distribution system. This project will be an extension of Project 4129, Assessment of Operating Conditions for Biological Filters in Drinking Water Treatment. This on-going project will conduct a survey to assess the state of the art of biological treatment in US systems. This project will end with a report and workshop addressing biological filtration, biologically stable water, and impediments to greater application of these technologies in the United States. The report will also document the extent of biologically active filter (BAF) use in the U.S. and the critical success factors for implementation of the technology. The workshop will highlight case studies, allow participants to identify concerns and research gaps that need to be addressed in order to advance the use of biological filtration, present critical success factors for implementation of biological filtration with application to emerging contaminants including nitrate and perchlorate, and serve as a technology transfer tool to gain broader acceptance of biological filtration as it is currently practiced and for future application to emerging contaminants. This work should also build upon work funded by the Research Foundation that was completed over seven years ago. In the project Investigation of the Biological Stability of Water in Treatment Plants and Distribution Systems (Project 154), the investigators noted that measurements for determining the biological stability of water were not always straightforward, and that disinfection affected biological stability. The outcome was that there was a need for improved models to predict biofilm growth. The second project, Optimizing Filtration in Biological Filters #252, completed in 1999, provides design objectives for biological filtration and guidance for selecting biofilter media and backwashing procedures. The focus was on single stage filters, but the scope was limited to pilot scale tests and a very small number of full scale facilities. The project also noted that there is a need for developing guidelines for biodegradable organic matter because this information is critical for the design and operation of biological treatment methods. To date, this need has not been addressed. A third project, Microbial Impact of Biological Filtration #917, finished in 1998, showed that biological treatment did not adversely impact the microbiological quality of water and in general could improve finished water quality. 83

90 Research Approach: Items include: (1) Literature review of factors affecting biological stability and how to measure and monitor it (analytical tools); (2) Survey results of water treatment plants with biologically active filters, including operational parameters and conditions; monitoring results from filtration plants and also membrane plants; (3) Summary of research on factors controlling/related to biofilm growth; and (4) Prepare issues document on next-level research needs. 84

91 REQUEST FOR PROPOSALS REAL-TIME DATA FUSION TO SUPPORT DISTRIBUTION SYSTEM OPERATION AND MANAGEMENT Objective: This study will use real-time data from multiple streams (e.g., real-time water quality sensors, real-time hydraulic models, pressure and flow sensors, pump operation, etc.) to detect water quality events and identify their common causes. The resulting methodology should be useable in real-time to direct response activities, as well as in a retrospective mode to feed water quality information into operations and maintenance (O&M) decisions. A key objective is to demonstrate the methodology in a field-scale pilot project, and to deliver the methodology as a software application that can be extended and incorporated as part of a supervisory control and data acquisition (SCADA) system. Recommended Budget: $450K Controversial Issues: EPA's Water Security (WS) Initiative is emphasizing operational benefits (along with security benefits) due to sustainability issues. EPA is trying to implement data fusion from five components (water quality, customer complaints, physical security, public health, sampling and analysis) that might provide information on both intentional and unintentional contamination events. When the 3rd phase of the WS initiative is completed (2010) with the 4 additional pilots, there will be significant progress made in the generation and interpretation of water quality and other component data. In other words, the data fusion element of this proposed project will be, to some extent, addressed. The phasing of this project should take the EPA WS pilots into consideration. Background: SCADA systems are a common component of water utilities distribution system infrastructure, relaying system data to the control room to support operational decisions. Recent water security research initiatives have considered real-time water quality monitors in the distribution system, and adding these to the existing SCADA infrastructure so that water quality information can help to provide warning of intentional contamination events (e.g., the USEPA s Water Security 85