| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating fluorine-containing waste water, by which the precipitation of minute calcium fluoride is restrained to obtain the treated water having stabilized quality and simultaneously produce the sludge having low water content at a small number of treatment steps. SOLUTION: The method for treating fluorine-containing waste water comprises: a reaction step of adding a calcium compound to fluorine-containing waste water to produce an insolubilized material containing calcium fluoride; a flocculation step of flocculating the produced insolubilized material of calcium fluoride; a separation step of subjecting the waste water containing the flocculated insolubilized material of calcium fluoride to solid-liquid separation to obtain sludge containing the flocculated insolubilized material of calcium fluoride and separated water; and a sludge return step of returning the sludge separated at the separation step to the reaction step as return sludge. A nonionic polymer flocculant is added at the flocculation step. COPYRIGHT: (C)2008,JPO&INPIT
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