FILTERING METHOD FOR ACTIVATED SLUDGE

摘要

PROBLEM TO BE SOLVED: To stably obtain high quality treated water by forming the good adhered matter layer of activated sludge on a filter body immersed and arranged in a biological reactor and efficiently separating the activated sludge. SOLUTION: An activated sludge soln. in a biological reactor 11 is circulated along the surface of a filter body 10 in an average flow rate of 0.05-0.4 m/sec. When the average flow rate of the activated sludge soln. circulating on the surface of the filter body is 0.05-0.4 m/sec, a fluidized dynamic filter layer approximate to a sludge boundary layer called as a sludge blanket among boundary layers between a sludge layer and a clean layer as if being generated in a settling tank is formed on the surface of the filter body in accompany with the progress of the filtration. In this way, the particles of the activated sludge can be efficiently filtered by the filtering capacity of the fluidized dynamic filter layer without increasing filtering resistance.