| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amt. of generated sludge and the amt. of a chemical agent to be used to a large extent by adding an inorg. flocculant to waste water of which the pH is adjusted to form a precipitate and separating the precipitate to add water thereto to elute at least coprecipitated harmful matter. SOLUTION: When fluorine is continuously treated, at first, fluorine-containing water 9 and sedimented sludge 12 are allowed to flow in a reaction tank 1 and NaOH 11 is added to both of them to be reacted therewith. Next, a polymer flocculant 13 is added to a flocculation tank 2 to form floc to separate fluorine- containing water into treated water 14 and a precipitate 15 in a sedimentation tank 3. Subsequently, the precipitate 15 is drawn out of the sedimentation tank 3 and adjusted in moisture in a storage tank to be allowed to flow in an elution tank 5 and sulfuric acid 16 is added to be reacted with the precipitate in this tank 5. The reaction soln. is allowed to flow in a flocculation tank 6 when a polymer flocculant 13 is added to form floc and conc. water and sedimented sludge 12 are separated in a sedimentation tank 7 and sedimented sludge 12 is adjusted in moisture in a storage tank 8 to be returned to the reaction tank 1.
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