REVERSE OSMOSIS MEMBRANE DEVICE AND METHOD FOR OPERATING SAME

摘要

To reduce effort and time required to wash a reverse osmosis membrane apparatus and to increase the operation rate of the reverse osmosis membrane apparatus to enable stable operation of the apparatus, a reverse osmosis membrane apparatus has a plurality of high pressure vessels 12a and 12b in parallel with each other with respect to the introducing passage 18 of the clarified seawater sw obtained by subjecting raw seawater to sterilization and removal of relatively large foreign substances such as dusts and microbes. The high pressure vessels 12a and 12b have therein a first-stage reverse osmosis membrane elements 14a and 14b, respectively. Concentrated seawater cs subjected to membrane separation in the high pressure vessels 12a and 12b are flown into a high pressure vessel 16. In the high pressure vessel 16, a plurality of reverse osmosis membrane elements 42, i.e. a second-stage reverse osmosis membrane element and reverse osmosis membrane elements of later stages, are arranged in series. When a detected value obtained by a differential pressure meter 56a or 56b provided for the high pressure vessel 12a or 12b exceeds a threshold value, introduction of the clarified sweater sw to the high pressure vessel having the differential pressure meter of which the detected value exceeds the threshold value is stopped, and the reverse osmosis membrane element is washed or replaced.