MEMBRANE SEPARATOR, METHOD FOR DETECTING LEAKAGE THEREOF, AND OPERATION METHOD FOR THE SAME

PROBLEM TO BE SOLVED: To detect leakage while permeation liquid being controlled as a whole, to stop promptly the filtration of a separating membrane after the detection of the leakage, and to restart normal operation at once by detecting the relative change in turbidity due to the operation change-over of each separating membrane module or a membrane separation series. SOLUTION: First, turbidity A is measured by a leakage detector 5, and the turbidity is stored in the detector while normal operation in which all of each membrane separation series is actuated being carried out. Next, the filtration in only one series among membrane separation series 2 is stopped in sequence. The filtration is controlled by closing an automatic valve 4 for the membrane separation series. When no difference is found between the turbidity A stored in the leakage detector and turbidity B which was measured by stopping the filtration in only one series, or when the turbidity is smaller than the turbidity B, no leakage occurs in the membrane separation series in which the filtration is stopped. However, when the turbidity A is larger than the leakage B, it is judged that leakage occurs in the membrane separation series in which the filtration is stopped.