METHOD AND DEVICE FOR TREATING WATER CONTAINING HARDLY BIODEGRADABLE ORGANIC SUBSTANCES

摘要

A method for treating water that contains hardly biodegradable organic substances by Fenton oxidation, whereby the use of an iron-based chemical agent and the generation of sludge can be both reduced, the dehydration property of the sludge can be improved and treated water with good water quality can be obtained. The aforesaid method comprises: adding, to water containing hardly biodegradable organic substances, hydrogen peroxide and an iron-based chemical agent, said iron-based chemical agent being added in an amount 0.005-0.2 times by mol as much as hydrogen peroxide, and allowing the resultant mixture to react for 1 hour or longer at pH 2-4; adding, to the thus oxidized water, an alkali agent to form insoluble matters; and then solid-liquid separating the thus formed insoluble matters. In this method, an alkali-sludge mixture, which is obtained by adding an alkali agent to a part of the separated sludge obtained in the solid-liquid separation step and mixing, is added as at least a part of the alkali agent to be added to the oxidized water in the insolubilization step.