| 摘要 |
PROBLEM TO BE SOLVED: To provide a washing method of a hollow fiber membrane module reducing the lowering of the filtering capacity of hollow fiber membranes caused by the twist or entanglement of hollow fiber membrane bundles and enabling long-term continuous filtering operation. SOLUTION: In a washing method of a hollow fiber membrane module used by an external pressure filtering system so that a raw soln. is supplied to the outer surfaces of hollow fiber membranes while a filtrate is taken out from the inner surfaces of the hollow fiber membranes, compressed air is injected on the filtrate side A of hollow fiber membranes in such a state that the hollow fiber membrane module is filled with a liquid on the raw soln. side B of the hollow fiber membranes to pressurize the hollow fiber membranes and the pressurized state on the filtrate side A of the hollow fiber membranes is released and, thereafter, the follow fiber membranes are washed with air bubbles on the raw soln. side B thereof. The time from the release of the pressurized state on the filtrate side A of the hollow fiber membranes to the start of air bubble washing on the raw soln. side B of the hollow fiber membranes is pref. set to 1-120 sec.
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