| 摘要 |
PURPOSE:To reduce concentration of PO4<3-> ion in permeated water through permeable membrane by adding Mg ions to org. filthy water contg. phosphate ions, treating then the water biologically, adding Al ions to the biological treating stage or to slurry discharged from the stage, and separating the PO4<3-> ions using membrane. CONSTITUTION:After adding Mg ions 2 to org. filthy water contg. phosphate ions, the filthy water is treated biologically in a biological treating stage 3. After adding further Al ions or Fe ions 5 to the biological treating stage or the slurry 4 discharged from the stage 3, solid in the water is separated from liquid with a membrane separation apparatus 6 into clean permeated water 7 contg. no SS and concentrated separated slurry 8. Thus, the concn. of PO4<3-> is reduced remarkably, so a removing stage of PO4<3-> by adsorption is no more necessary, or frequency for regenerating adsorbent is reduced extremely even if the adsorption stage of PO4<3-> ion is executed additionally. Accordingly, disposal of regenerated waste liquid is facilitated extremely because crystallization or centrifugal separation, etc. Which has been required conventionally, is unnecessary. |
