DEVICE FOR TREATING MEMBRANE-FILTRATION WASTE WATER AND ITS OPERATION

摘要

PROBLEM TO BE SOLVED: To decrease the amt. of sludge depositing inside a hollow-fiber membrane by changing the flow velocity on the membrane face in accordance with the sludge concn. in a waste water to be treated supplied to a membrane- filtration waste water treating device. SOLUTION: This treating device is provided with a control means 16 capable of changing the flow velocity by on the membrane face by adjusting a circulating pump 3 and the opening degree of a valve 14 in accordance with the sludge concn. in a waste water to be treated. In this case, the permeation flux can be kept high by suppressing the deposition of sludge on the surface of the inner wall of the membrane of a module 4 to prevent the clogging of the membrane, and operation is continued for a long time without cleaning the module.