AWWA JAW28476

Three slow sand filter plants in northern Idaho were studied to evaluate their ability to produce good quality water and to control Giardia cysts, to determine the effects of design and operating factors on treatment performance, and to assess the effectiveness of monitoring and sanitary surveys. During the one-year study, the plants were sampled weekly for measurement of turbidity, total and fecal coliforms, and heterotrophic plate count. Samples were also analyzed for Giardia cysts and particulates. Results showed that if a slow sand filter is designed and operated according to accepted standards, it should provide consistent and effective water treatment, including a reduction in the concentration of Giardia cysts. Includes 14 references, tables, figures.