| 摘要 |
PROBLEM TO BE SOLVED: To provide an operation method in a pressurized, head difference type, sucking type tank membrane separation device, or dipped type membrane separation device, by which high recovery is attained and stable membrane filtration is performed. SOLUTION: In a filtration process of the membrane separation device filtering treating object water by a membrane module set in a tank by pressurizing, head difference or differential pressure of suction pressure, liquid level of the treating object water in the tank is controlled above an upper end face of separation membranes composing the membrane module. Besides a filtration process A filtering by all the separation membranes, a filtration process B is performed in which the liquid level of the treating object water in the tank is lowered below the upper end face of the separation membrane composing the membrane module by stopping supply of the treating object water to the tank and continuing filtration. COPYRIGHT: (C)2007,JPO&INPIT
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