| 摘要 |
PURPOSE:To efficiently remove phosphorus by adding Al salt or Fe salt to waste water contg.-phosphoric acid, separating and removing precipitate and thereafter dissolving an aggregate in mineral acid and bringing the soln. into contact with Zr compd. or Ti compd. CONSTITUTION:Al salt such as aluminum sulfate and aluminum polychloride or Fe salt 2 such as iron polysulfate is added to waste water 1 contg. phosphate ion and this soln. is mixed in an agitation tank 3 to produce flock. Thereafter slurry is introduced into a precipitation tank 4 and produced flock is precipitated and removed, and treated water 5 free from phosphoric acid is obtained. Separated precipitation sludge 6 is intermittently discharged and fed to an acid treatment tank 7 and sludge is dissolved by adding mineral acid 8. The dissolved liquid 9 is brought into contact with oxide or the like of Zr or Ti in a column 10 and PO4<3-> incorporated in the soln. 9 is adsorbed and removed. Thereby the disposal cost for dehydrated cake can be dispensed with.
|
