| 摘要 |
PROBLEM TO BE SOLVED: To provide a flocculation treatment method for silicon particulates and/or colloidal silica containing waste water capable of obtaining treated water having good water quality by subjecting the waste water containing the silicon particulate and/or colloidal silica generated in a semiconductor manufacturing process or the like to flocculation treatment and efficiently recovering the silicon particulates and/or the colloidal silica. SOLUTION: The flocculation treatment method for adding an inorganic flocculant to the flocculation treatment to the waste water containing the silicon particulates and/or the colloidal silica comprises (a) regulating the pH of the waste water to 6.5 or below, then (b) regulating the pH to 6.5 to 7.5 and subjecting the waste water to the flocculation treatment, (b) regulating the pH of the waste water to 7.5 and over, then regulating the pH to 6 to 7.5 and subjecting the waste water to the flocculation treatment or (c) adding an oxidizing agent to the waste water to adjust the pH to 4 to 8 and subjecting the waste water to the flocculation treatment. COPYRIGHT: (C)2004,JPO&NCIPI
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