| 摘要 |
PROBLEM TO BE SOLVED: To provide a membrane separation method by which it is possible to detect a damaged module while a membrane separation process is continued and replace the module through correct detection, even when the difference in water quality between a liquid to be treated and a treated liquid is small. SOLUTION: The membrane separation process is performed using a plurality of units 1a, 1b, and the like, composed of a plurality of modules 2a, 2b, and the like, having separation membranes 3a, 3b, and the like. Further, a permeating liquid obtained from each of the modules 2a, 2b, and the like, is collected as a confluent flow per unit and then is taken out into permeating liquid branched channels 16a, 16b, and the like, having detectors 18a, 18b, and the like, respectively. Next, the unit showing abnormality is detected by comparing the readings of the detectors 18a, 18b, and the like, mounted on the respective permeating liquid branched channels 16a, 16b, and the like, while the membrane separation process is performed under substantially the same conditions per unit. After that, the modules 2a, 2b, and the like, of the unit in which abnormality is detected are sequentially stopped under such a state that the membrane separation process is continued in the other units. Thus, the damaged module is detected based on variations in a detection value by the detectors 18a, 18b, and the like.
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