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GROWTH OF HETROTROPHIC BIOFILMS IN A WATER DISTRIBUTION SYSTEM SIMULATOR
Meckes*, M, R C. Haught*, D. Cmehil, K M. White*, AND J C. Blannon*. GROWTH OF HETROTROPHIC BIOFILMS IN A WATER DISTRIBUTION SYSTEM SIMULATOR. Presented at World Water & Environmental Resources Congress 2004, Salt Lake City, UT, June 27 - July 01, 2004.
To inform the public.
The U.S. EPA has designed and constructed a distribution system simulator (DSS) to evaluate factors which influence water quality within water distribution systems. Six individual 25 meter lengths of 15 cm diameter ductile iron pipe are arranged into loop configurations. Each loop is configured to operate independently with any number of the six loops under various experimental conditions simultaneously.
Heterotrophic bacteria can colonize; pipe surfaces, cracks, and crevices producing a complex micro environment known as "biofilm." These biofilms can be highly resistant to many disinfection methods and techniques. The rate of heterotrophic biofilm attachment to and growth on sterile coupons was evaluated using the DSS under two concentrations of residual chlorine and two concentrations of organic carbon. Results indicate that attachment and growth of heterotrophic biofilms occurs within hours of exposure to potable water. These results suggest that sloughed or shed cells from established biofilms within the simulator may quickly attach and colonize wetted surfaces. The implication here is that replaced or repaired distribution system components will be rapidly colonized by biofilms following installation.