Many water utilities deal with water quality problems in the distribution system due to low water usage. This study uncovers the many problems of low usage and reports on the variety of mitigation practices used by North American utilities. An included CD-ROM provides decision support software to help utilities systematically weigh the costs and benefits of a variety of best management practices (BMPs) for mitigating the water quality issues caused by low usage and thus cutting down on customer complaints and higher distribution costs.
One cause of distribution system water quality problems is from low usage due to new developments or reduced demand. Low usage causes increased water age throughout the system which can lead to a number of water quality problems, including decreased disinfectant residual, sedimentation, increased temperatures, and taste, odor, and color problems. To address these issues and maintain compliance with regulatory standards, utilities have implemented design/construction and O&M based best management practices (BMPs) with varying success. The objectives of this project were to (1) identify water quality changes that occur in the distribution system as a result of low or diminished use areas, in particular, areas of new development with low initial customer usage and established areas undergoing diminished use; and (2) recommend best management practices (BMPs) on minimizing water quality problems in such areas. Utilities must provide potable water to small and large users, new and old developments, and central and remote customers while accounting for changing demographics and demand patterns. In order to maintain adequate water quality and satisfy all of these needs, water utility operators must have the ability to choose sound design and O&M-based BMPs, and defend their decisions. The development of the DST software in this research project allows utility operators to do this by providing a method to compare the costs and benefits of various BMPs and thus make better decisions. The companion CD-ROM contains a decision support tool for selecting the most appropriate BMP for reducing water quality problems due to low usage.
Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
Offering a high-level view of key distribution system water quality issues that utilities will confront in the coming decades, and a new view of an integrated treatment process, this book covers such topics as microbial regrowth and recontamination, risks associated with release of trace metals from system scale, and impacts of secondary disinfection practices. This resource targets water utility managers, water quality professionals, policy makers, regulators, consultants, and educators.
The Water Science and Technology Board has released the first report of the Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks, which is studying water quality issues associated with public water supply distribution systems and their potential risks to consumers. The distribution system, which is a critical component of every drinking water utility, constitutes a significant management challenge from both an operational and public health standpoint. This first report was requested by the EPA, as the agency considers revisions to the Total Coliform Rule with potential new requirements for ensuring the integrity of the distribution system. This first report identifies trends relevant to the deterioration of drinking water quality in distribution systems and prioritizes issues of greatest concern according to high, medium, and low priority categories. Of the issues presented in nine EPA white papers that were reviewed by the committee, cross connections and backflow, new or repaired water mains, and finished water storage facilities were judged by the committee to be of the highest importance based on their associated potential health risks. In addition, the report noted that two other issues should also be accorded high priority: premise plumbing and distribution system operator training. This first report will be followed in about 18 months by a more comprehensive final report that evaluates approaches for risk characterization and identifies strategies that could be considered to reduce the risks posed by water-quality deteriorating events.
A typical water distribution system is complex and chaotic with varying piping configurations, water flows, chemical reactions, and microbiological activity. It is therefore no surprise that monitoring water quality can be a daunting task, not to mention dealing with the devastating and costly effects of: Noncompliance with the Lead and Copper Rule Pinhole leaks in water service lines and private plumbing Vulnerability to microorganisms in the water distribution system Unwanted side effects from treatment chemicals Mistakes in treatment chemicals and dosage amounts These common water quality issues can be avoided by routinely monitoring key water quality parameters in the distribution system in a controlled and standardized manner. While proactive monitoring costs money, having water quality problems is even more costly. Water Distribution System Monitoring: A Practical Approach for Evaluating Drinking Water Quality provides a practical step-by-step approach and open-source technology for proactive water quality management. It describes a method for routinely monitoring the water distribution system by: Assembling a standardized monitoring station Planning a monitoring strategy, and Interpreting and using the water quality data Deliver safe and economical drinking water to your customers. Why wait three years to find out if the water system is in compliance with the Lead and Copper Rule? Why guess which corrosion control chemical is the right one? Why guess how much disinfection is needed in the water distribution system? Optimize your chemical usage, minimize your operational expenses, and confirm that the water is safe. Laying out a path to quality control and process improvement, this book provides the tools for well-defined and measurable control of water quality.
This book is an outcome from the International Expo 'Water and Sustainable Development' held in Zaragoza (Spain) in 2008. Support from the Spanish Ministry of Environment, Caja Rioja, Government of Aragon, and the World Bank is acknowledged. 'Few resources will play a more important role in shaping our economic future, or face more daunting challenges, than water. This internationally acclaimed team of experts has produced a first-rate volume that is full of intriguing, practical ideas for meeting those challenges in a rich variety of institutional settings.' Tom Tietenberg, Mitchell Family Professor of Economics, Emeritus, Colby College, USA 'This volume brings together two critical but interrelated dimensions of water challenge, i.e. water pollution, particularly from non-point sources, and water conservation. The editors are well known experts on the subject as are the contributors.' R. Maria Saleth, International Water Management Institute, Sri Lanka and Associate Editor, Water Policy 'The profound contribution of this volume is that it brings together various economic concepts and policy dilemmas regarding water shortages, non-point source pollution, efficiency of water use and irrigation technology. Recommended reading for anyone working in the area of water management.' Henk Folmer, University of Groningen and Wageningen University, The Netherlands As countries face deteriorating water and environmental quality as well as water shortages, pollution control and the efficiency of water use become of paramount importance. Agriculture is one of the main non-point polluters of water bodies and irrigation for agriculture is one of the main consumers of water. While it is very hard to regulate pollution from agriculture, attempts have been made via economic and command and control instruments, and also through investments in technologies and ecosystems recovery. Coping with non-point pollution takes the form of both policy intervention and technology development. Likewise it is recognized that irrigation efficiency varies across countries, influenced by both technology and supporting adoption policies. Countries that lead in irrigation technology and supporting policies have certain traits in common. They face very high scarcity and are pushed to find innovative solutions, both technical and policy related. The recent multibillion investments in irrigation technologies in Spain, and similar proposals in Australia, for example, highlight the potential of irrigation technologies to cope with scarcity and water quality degradation. This book reviews all of the above issues, presents experiences in selected countries, and assesses the degree of success of alternative policies for coping with non-point water pollution and improving irrigation efficiency.
Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
This book is the result of a joint research effort led by the U.S. National Academy of Sciences and involving the Royal Scientific Society of Jordan, the Israel Academy of Sciences and Humanities, and the Palestine Health Council. It discusses opportunities for enhancement of water supplies and avoidance of overexploitation of water resources in the Middle East. Based on the concept that ecosystem goods and services are essential to maintaining water quality and quantity, the book emphasizes conservation, improved use of current technologies, and water management approaches that are compatible with environmental quality.
