| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of efficiently washing a filtration membrane which can prevent deposits from depositing on the surface of the membrane and prevent the membrane from being progressed in its clogging, and can perform a stable operation at the time of high permeating flux when washing the filtration membrane of a dipped type membrane separation apparatus with a membrane surface stream of gas/liquid mixed liquid. SOLUTION: When washing the hollow fiber membrane module 6a of the membrane separation apparatus dippedly disposed in a water treating tank with the membrane surface aeration stream from an air diffuser provided at the lower part of the membrane module 6a, increase of membrane differential pressure is divided to that by a cake layer attached to the outer surface of the membrane module 6a, and that by a gel layer attached to the inner wall of membrane holes. Membrane surface optimum aeration volume suppressing a membrane differential pressure rising speed to the minimum is found for every membrane permeating flux using a membrane clogging model, and the membrane surface optimum aeration volume is set for respective permeation flux. Thus, the membrane differential pressure increase during continuous operation is greatly suppressed, to allow steady operation of the membrane separation, even in case of high permeating flux. COPYRIGHT: (C)2006,JPO&NCIPI
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