| 摘要 |
PROBLEM TO BE SOLVED: To treat under high stable permeation flux while keeping removing ratio of nutrient salts of nitrogen, phosphorus or the like high in the case of executing final high order treatment of sewage using two stage reverse osmosis membrane module. SOLUTION: The treating method is for executing final high order treatment in the sewage treatment by the two stage reverse osmosis membrane modules 61, 62. In such a case, a reverse osmosis membrane module provided with a coating layer having an electrically neutral hydrophilic group or a coating layer having a hydrophilic group and having <=±10 mV surfaceζ-potential at pH 6 on the surface is used as the pre-stage reverse osmosis membrane module 61.
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