MEMBRANE SEPARATION DEVICE OF ACTIVATED SLUDGE TREATMENT SYSTEM, MEMBRANE SEPARATION METHOD, AND ACTIVATED SLUDGE TREATMENT SYSTEM EQUIPPED WITH MEMBRANE SEPARATION DEVICE

摘要

PPROBLEM TO BE SOLVED: To provide a membrane separation device capable of reducing the frequency of cleaning with chemicals by suppressing the deposition of sludge to a membrane element and, thereby, increasing the quantity of permeated water obtained per unit term without making the whole system large-sized in regard to the membrane separation device that filtrates treated water from the treated sludge by using the membrane element. PSOLUTION: A sludge circulation circuit is constituted between a biological reaction vessel 1 and a membrane module 2 housing a tubular membrane element. The sludge is circulated in the sludge circulation circuit, the sludge is allowed to pass into the membrane module 2 at relatively high speed, at the same time, the filtration is performed for one part of the sludge and the treated water is extracted. Further, by making washing water pass periodically in the reverse direction to the filtration direction of the treated water, solid material deposited onto membrane element is stripped off. PCOPYRIGHT: (C)2004,JPO&NCIPI