Coagulation-sedimentation treatment method of ion-containing wastewater

摘要

PROBLEM TO BE SOLVED: To provide an ion-containing drainage treatment method improved so as to obtain stable treated water quality by particularly improving the turbidity of the treated water in the ion-containing drainage treatment method of circulating a part of sludge, mixing the circulated sludge with an alkali compound and loading it into the ion-containing drainage.;SOLUTION: A flocculation precipitation treatment method of the ion-containing drainage comprises forming an insoluble substance including a hardly soluble salt by loading the ion-containing drainage with the alkali compound which forms the hardly soluble salt by reaction with the ion, flocculating the insoluble substance by loading the sludge containing the produced insoluble substance with a polymer flocculant, recovering concentrated sludge by carrying out sedimentation and separation of the flocculated insoluble substance, mixing a part of the recovered concentrated sludge and the alkali compound, and using obtained alkali compound-containing concentrated sludge as the alkali compound of the above reaction, wherein a cationic polymer flocculant and an anionic polymer flocculant are used together as the polymer flocculant.;COPYRIGHT: (C)2008,JPO&INPIT