Practices To Prevent Microbiological Contamination Of Water Mains

"The objective of this project was to identify and develop Good Practices that can realistically be implemented by water utilities for preventing microbiological contamination associated with the installation, rehabilitation, and repair of water mains." -- Executive summary.

This publication addresses the factors affecting the presence and growth of micro-organisms in piped networks as well as the practices of water supply organisations that can directly or indirectly influence them. The book shows that there are often public health reasons for adopting a more proactive approach to many of the traditional practices used in designing, operating and maintaining distribution networks, and to modifying the composition of the water that is fed into those networks.

Water distribution systems are made up of pipe, valves and pumps through which treated water is moved from the treament plant to homes, offices, industries, and other consumers. The types of materials and equipment used by each water system are usually governed by local conditions, past practices, and economics. Consequently, drinking water professionals must be knowledgeable about common types of equipment and operating methods that are available. Completely revised and updated, Water transmission and distribution includes information on the following: distribution system design and operation and maintenance ; piping materials ; valves, pumps, and water meters ; water main installation ; backfilling, main testing, and installation safety ; fire hyfrants ; water storage ; water services ; cross-connection control ; motors and engines ; instrumentation and control ; information management and public relations.--Cover page [4].

Legionnaires' disease, a pneumonia caused by the Legionella bacterium, is the leading cause of reported waterborne disease outbreaks in the United States. Legionella occur naturally in water from many different environmental sources, but grow rapidly in the warm, stagnant conditions that can be found in engineered water systems such as cooling towers, building plumbing, and hot tubs. Humans are primarily exposed to Legionella through inhalation of contaminated aerosols into the respiratory system. Legionnaires' disease can be fatal, with between 3 and 33 percent of Legionella infections leading to death, and studies show the incidence of Legionnaires' disease in the United States increased five-fold from 2000 to 2017. Management of Legionella in Water Systems reviews the state of science on Legionella contamination of water systems, specifically the ecology and diagnosis. This report explores the process of transmission via water systems, quantification, prevention and control, and policy and training issues that affect the incidence of Legionnaires' disease. It also analyzes existing knowledge gaps and recommends research priorities moving forward.

According to the Centers for Disease Control and Prevention, 32 percent of waterborne disease outbreaks are caused by pathogen intrusion in the water distribution system. Incorporating disinfection practices for water mains and storage facilities can reduce the risk of microbial contamination. This handy guidebook provides all the correct field practices for preventing microbial contamination of the water flowing in water mains, storage tanks, and other distribution system components. NOTE TO WATER UTILITIES: To ensure that mains and storage facilities are properly disinfected prior to use, AWWA advises that water utilities should insist that their pipeline contractors have and use this book.

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 provides a state-of-the-art review on approaches and methods used in assessing the microbial safety of drinking-water.

With an increasing population, use of new and diverse chemicals that can enter the water supply, and emergence of new microbial pathogens, the U.S. federal government is faced with a regulatory dilemma: Where should it focus its attention and limited resources to ensure safe drinking water supplies for the future? Identifying Future Drinking Water Contaminants is based on a 1998 workshop on emerging drinking water contaminants. It includes a dozen papers that were presented on new and emerging microbiological and chemical drinking water contaminants, associated analytical and water treatment methods for their detection and removal, and existing and proposed environmental databases to assist in their proactive identification and regulation. The papers are preceded by a conceptual approach and related recommendations to EPA for the periodic creation of future Drinking Water Contaminant Candidate Lists (CCLsâ€"produced every five yearsâ€"include currently unregulated chemical and microbiological substances that are known or anticipated to occur in public water systems and that may pose health risks).