AWWA ACE95087

Drinking water utilities are faced with ever-increasing regulations on the quality of finished water as defined by the Safe Drinking Water Act under the Surface Water Treatment Rule, the Total Coliform Rule, the Lead and Copper Rule, and the Disinfection Byproduct Rule. Utilities must comply with each rule, but control measures for one set of regulated constituents often conflict with compliance under another rule. For example, control of biofilms and coliforms in water distribution systems is typically attempted by increasing the disinfectant microbiological problem, and may adversely affect water quality by increasing disinfectant byproducts and corrosion. An integrated approach has been instigated by the Center for Biofilm Engineering with help from academic co-investigators and industry to address this multi-faceted problem. Key results from our research and that of others indicates that a common factor in biofilm, disinfectant byproducts and corrosion control is the concentration of biodegradable organic matter (BOM) in water. Reduction of BOM results in less available substrate for biofilm growth; a subsequent reduction in the amount of disinfectant required for microbial control and therefore decreased disinfection byproduct formation; and decreased corrosion. An effective method for reducing BOM is biological filtration, where removal of BOM by biofilms on the filter medium is optimized. This research is directed toward understanding the processes responsible for the management of biofilms in these low-nutrient environments, whether beneficial (biological filtration) or detrimental (in the distribution system).