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Control of Biofilm Growth in Drinking Water Distribution Systems


This seminar publication discusses the composition of biofilms, factors that favor their formation, how to recognize a biofilm problem, biofilm control strategies, regulatory issues, and resources for assistance. Distribution system monitoring and biofilm control strategies require a thorough understanding of many aspects of water supply and distribution, as well as information about water chemistry and microbiology. When plant personnel have knowledge of the conditions that allow microbes to pass into the distribution systems and the factors that favor microbial growth, they are able to develop a comprehensive monitoring strategy to identify trouble spots before problems arise. This strategy includes monitoring of not only easy-to-reach outlets but peripheral portions of the distribution system. The program provides a data base from which to detect changes in bacterial quality and to determine the sources of the contamination: biofilms, cross connections, or treatment breakthrough. The biofilm control plan is not only a remediation plan but a prevention program as well. Systems that maintain an adequate treatment residual, flush the distribution lines regularly, and practice good pipe maintenance will have a lower risk of developing a biofilm problem.

This publication was prepared cooperatively by EPA's Offices of Ground Water and Drinking Water, Technology Transfer and Regulatory Support, and Environmental Engineering and Technology Demonstration. The publication is of interest to federal, state and local regulatory officials, consultants, manufacturers, and drinking water utility administrators and staff.

For more information on this {and similar} research, please visit our research web site

Office of Research & Development | National Risk Management Research Laboratory

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