| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent flux deterioration and biofouling due to organic substance adhering to a membrane surface in an RO (reverse osmosis) membrane separator when treating and recovering organic substance-containing waste water by using the RO membrane separator and further to prevent adverse influence of RO retentate on waste water treatment or the like by efficiently reducing chemical oxygen demand value of the RO retentate. <P>SOLUTION: After an alkali is added to the organic substance-containing waste water to adjust pH to 9.5 or more while adding a scale preventive agent thereto, the waste water is passed through the RO membrane separator 2. While adding a sulfur compound containing a peroxide group to the RO retentate, UV irradiation is applied thereto to carry out oxidation treatment. By adjusting pH of the water supplied to RO to 9.5 or more, the biofouling in the RO membrane separators is prevented and nonionic surfactants are prevented from adhering to the membrane surface to prevent the flux deterioration. By adding the scale preventive agent, membrane surface clogging due to calcium carbonate scale in high pH condition is suppressed. Addition of the sulfur compound and UV irradiation generate sulfuric acid radicals having very high oxidizing power and organic substances in the retentate are decomposed to gaseous carbon dioxide and gaseous nitrogen and are removed from the water. <P>COPYRIGHT: (C)2007,JPO&INPIT |
