AWWA ACE63201

This slide presentation outlines a study on biosand filtration for point-of-use drinking water treatment. Specific goals of the study included: replicate filter preparation and use conditions typical of a developing country setting; characterize the flow condition in the filter; determine the ability of the BSF to reduce concentrations of bacteria, human enteric viruses and bacteriophages, and protozoan parasites; and, determine changes in filter effectiveness with length of filter operation. Laboratory study procedures included: filter preparation methods designed for use in developing countries; crushed granite gravel sieved and washed; 20 or 40 liters of surface water seeded with challenge microbes and poured through filter daily; daily filtration for six to eight weeks; and, microbial samples analyzed weekly. Key aspects of laboratory study results include: hydraulic flow condition; filter ripening (or maturation) and flow rate; E. coli reductions and ripening; virus and bacteriophage reductions; effect of filter pause time on microbial reductions; filtrate water after overnight retention in filter bed versus filtrate water from delivered daily dose; effect of cleaning the filter on E. coli reductions; and, Cryptosporidium experiments. Includes figures.