FILTRATION METHOD AND FILTRATION SYSTEM

PROBLEM TO BE SOLVED: To treat turbid water containing dust of red clay, etc., surely and inexpensively without using chemicals such as a coagulant by placing a coarse filter medium, a fine contact filter medium is placed on it, and a catchment pipe having numbers of holes in its side wall is installed in or on the contact member. SOLUTION: The bottom part 2 of a housing 1 is inclined, and a discharge duct 3 is erected in the middle of the bottom part 2. A water supply pipe 4 having a great number of pores 11 is installed in the bottom part 2, and gauze is placed on a joist installed on the pipe 4, and a coarse filter medium 7 is placed on the gauze. A fine contact filter medium 8 is placed on the medium 7, and a catchment pipe 9 is installed on the medium 8, and a weight 10 is placed on the pipe 9. Turbid water introduced from inflow port 4a flows out from the pares 11 and is settled in a precipitation space 2a below a guide G, and only supernatant ascends from the gap between the guide G and the water supply pipe 4, after passing through the gaps of the filter media 7, 8 to be removed of dust, etc., is introduced from pores 13 into the catchment pipe 9 to be taken out from an outflow port 9b as purified water.