| 摘要 |
PROBLEM TO BE SOLVED: To prevent a deterioration in permeation flux during water treatment using a separation membrane (membrane separation) by controlling the contamination of the separation membrane. SOLUTION: After water to be treated is oxidized with an oxidizing agent 7 to reduce membrane contaminants and consume reducing substances in the water to be treated, the chlorine concentration in the water to be treated is kept in the prescribed numeric range where biological contamination of the separation membrane 1 can be controlled without deteriorating the performance of the separation membrane 1. Subsequently the water to be treated is supplied to the separation membrane 1. As the oxidation treatment of the water to be treated with the oxidizing agent 7 reduces organic membrane contaminants and the like, the contamination of the separation membrane 1 with organic substances is prevented. As the above oxidation treatment also consumes the reducing substances in the water to be treated, the chlorine concentration in the water to be treated is easily kept in the prescribed numeric range. Thereby the biological contamination of the separation membrane is controlled, so that the deterioration in the permeation flux can be prevented to the utmost. COPYRIGHT: (C)2005,JPO&NCIPI
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