| 摘要 |
PROBLEM TO BE SOLVED: To stably treat over a long time by preventing a decrease in flux of a RO (reverse osmosis) membrane when biological treatment water-containing water is subjected to RO membrane separation treatment and is purified. SOLUTION: In a method for carrying out the RO membrane separation treatment to purify water to be treated in which the biological treatment water of waste water is contained and the concentration of TOC (total organic carbon) is 0.5 to 100 mg/L, a polyvalent metal ion in the water to be treated is removed and then the RO membrane separation treatment is carried out. The polyvalent metal ion causing a binder to fouling substances having relatively high adhesion such as proteins or polysaccharides which are RO membrane blockage main substances when the biological treatment water-containing water is served as RO supply water and promoting adherence of the fouling substances to the membrane surface is removed prior to the RO membrane separation treatment to suppress promotion of adhesion of such the fouling substances to the membrane surface, thereby preventing a decrease in flux from blocking the membrane. COPYRIGHT: (C)2006,JPO&NCIPI
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