PURPOSE: To provide a compsn. for a flocculating agent which exhibits a better flocculating effect than in the case of adding an inorg. flocculating agent and a cationic flocculating agent separately by mixing both agents ata specific ratio.
CONSTITUTION: A mixed soln. consisting of 360mg/l polyethylene imine, 586mg/l aluminum chloride is added to the waste water of chemical groundwood pulp having 6560 chromaticity and 6.75pH from a paper pulp plant; thereafter the soln is adjusted to 7.0pH and is subjected to a flocculating precipitation treatment by adding an aninoic org. flocculating agent at 1mg/l. When the chromaticity of the supernatant water is measured, the liquid has 92 chromaticity and is virtually colorless and transparent. A better flocculating effect than in the case of adding the respective flocculating agents alone or separately is obtd. and particularly the removal of chromaticity is high in the case of using mixedly the cationic flocculating agent and the inorg. flocculating agent in a way not to produce an insoluble resulted product of reaction in the state of an aq. soln. as in this invention.
WAKITA MASAAKI
SEKIKAWA AYAKO
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