This research was carried out to appreciate a slow sand filtration treatment by an investigation of suspended matter distribution in sand beds with covered of slow sand filter models (covered filter) . The core-sampler was inserted to take suspended matter in slow sand filter model beds during the filter operation when the filters were not easy to clog in summer. The following results were obtained.
Normahzed head loss value was increased at covered filter than at open filter after about 25 days of filter run. From the depth distribution of the Suspended Solid (SS) and Total Organic Carbon (TOC), covered filter detained larger amount of suspended matter than open filter. And suspended matter was detained at the extremely surface layer of the sand column with covered filter. The depth distribution of the Chlorophyll α indicated nearly opposite profile as SS, TOC distribution.