Biological filtration (biofiltration) is the operational practice of managing, maintaining, and promoting biological activity on granular media in a high-rate, gravity filter to enhance the removal of organic and inorganic constituents before introducing treated water into the distribution system. In response to recent, and expected future, regulatory provisions, utilities may consider converting existing conventional filters to biofilters since they have been shown to improve water quality, specifically for taste and odor (T&O) removal, manganese (Mn) removal, ammonia (NH3) removal, minimization of disinfection by-products, disinfectant stability, and effluent biostability. However, operational/hydraulic challenges and short-term water quality deterioration may be experienced immediately after starting to operate biofilters in “biological mode.” Weighing these risks and benefits can be difficult for utilities considering conversion, since the overall costs and other key factors for successful conversion are poorly characterized.
The overall objective of this project was to catalog and summarize the existing knowledge and experience on biofilter conversion, focusing on planning, evaluation, and conversion implementation.
Upadhyaya, G., and Brown, J. "Biofilter Conversion Guidance Manual."Water Research Foundation: Denver, Colo., 2017.