CBE Research Initiative: 

Drinking Water

Principal Investigators: A. Camper, W. Jones, G. McFeters.

Research Staff: M. Burr, L. Goodrum

The Drinking Water Research Initiative is a collection of projects on the beneficial and detrimental effects of biofilms in potable water treatment and distribution. We are privileged to work with co-investigators from other academic institutions, consulting companies and industries throughout North America and Europe.

Highlights:

Project Sponsors. The majority of funding for the research initiative has come from industrial money through the American Water Works Association Research Foundation. Other sources include the National Water Research Institute, Anjou Researche and Metcalf & Eddy, the USEPA through the Drinking Water Assistance Program from the Montana Water Center, and programs within the university system. Nearly all of these projects include a field scale component and/or interaction with a water utility.

Facilities. We have designed and built a pipe loop pilot system at the City of Bozeman Water Treatment Plant. The system was designed to simulate worst-case distribution system conditions and is composed of five, forty-foot mild steel pipes (4" diameter) with removable coupons for biofilm and deposit sampling. Results from this system have been compared with those from laboratory annular reactors and full-scale distribution systems.

Key Findings. We have found that low concentrations of chlorine may enhance the numbers of biofilm heterotrophs, especially coliforms. The effect is more pronounced on ferrous metal surfaces. Research has supported the industrial observation that corrosion control implemented to reduce lead and copper concentrations may also reduce the proliferation of biofilms on iron pipe surfaces. Recent findings suggest that components of TOC not available for the growth of planktonic bacteria support the growth of biofilm organisms. Investigations on the survival of frank bacterial pathogens in drinking water biofilms have shown that some organisms persist for extended periods of time, even under chlorination, although they cannot be recovered via conventional culturing techniques. Particles released from biological filters used to reduce the organic carbon concentrations in drinking water can transport bacteria to distribution system biofilms, but these organisms have a limited long-term impact on biofilm. To further this work, molecular probes are being used to monitor the behavior of enteric bacterial pathogens and indicator organisms in laboratory-scale biological filters.

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For more information, e-mail Anne Camper.