PURPOSE: To set the injection amount of an aluminum compd. to the necessary min. degree and to also stabilize the quality of treated water in the removal treatment of the fluorine component (fluorine ion) of fluorine-containing waste water.
CONSTITUTION: The necessary concn. of aluminum is calculated according to a predetermined calculation formula or multiplication coefficient on the basis of the fluorine concn. signal from a waste water fluorine concn. analyser 3 and the aluminum concn. signal from a waste water aluminum concn. analyser 4 is subtracted from the calculated value and the injection amount of aluminum compd. is operated by an operation circuit multiplying the inflow waste water flow rate signal from a waste water flow rate detector 1 to inject the compd. into a reaction tank 6. From the polarity and magnitude of the deviation between an objective fluorine concn. value and the fluorine concn. measured value of treated water, the injection amount of the compd. is controlled while a correction magnification coefficient is intermittently operated and corrected and the quality of treated water is stabilized.
TOYAO MAMORU
ASANO MUNEMITSU
TAKADA TOKIO
TAKAMI HIDETOSHI
ORGANO KK