METHOD FOR TREATING FREE CHLORINE-CONTAINING WASTE WATER

Japanese Patent JP2015213880

A

PROBLEM TO BE SOLVED: To provide a method for efficiently treating waste water containing the free chlorine caused by sterilization or the like while preventing deterioration of a polyamide-based RO membrane.SOLUTION: The method for treating free chlorine-containing waste water comprises the steps of: adding a combined chlorine agent to the free chlorine-containing waste water; and treating the combined chlorine agent-added free chlorine-containing waste water in a RO (reverse osmosis) membrane. The combined chlorine agent is a chemical containing a nitrogen compound for generating combined chlorine and is preferably sulfamic acid or salt thereof. It is preferable that a blended product is used, which product is obtained by blending a chlorine-based oxidizer being a free chlorine agent in the sulfamic acid or salt thereof. The chlorine-based oxidizer is preferably hypochlorous acid or salt thereof. It is preferable that after the pH of the free chlorine-containing waste water is adjusted to 7.5 or lower, the combined chlorine agent is added thereto.

WO/2019/163800	WATER TREATMENT APPARATUS, WATER TREATMENT METHOD, AND METHOD OF STARTING WATER TREATMENT APPARATUS
WO/2005/068372	APPARATUS AND METHOD FOR PURIFYING WATER

HAYAKAWA KUNIHIRO
UCHIDA TAKAHIKO

JP2014098438A

December 03, 2015

May 12, 2014

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KURITA WATER IND LTD

C02F1/44; B01D61/02; B01D61/04; B01D69/12; B01D71/56; C02F1/58; C02F1/76; F28F19/00; F28G13/00

JP2010201313A	2010-09-16
JPH01104386A	1989-04-21
JPH01104310A	1989-04-21
JP2009165928A	2009-07-30
JP2006035004A	2006-02-09
JPH06304559A	1994-11-01
JPH01135506A	1989-05-29

WO2012133620A1	2012-10-04
WO2011125762A1	2011-10-13
US20080257832A1	2008-10-23

Yuji Hayakawa
Keisuke Murasame

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