| 摘要 |
PURPOSE:To increase the release rate of phosphorus and to remove efficiently the phosphorus in waste water by admitting part of feed water into a dephosphorization tank in the stage of migrating the phosphorus in the feed water by using an aeration method into activated sludge and releasing the phosphorus in the excess sludge in the dephosphorization tank. CONSTITUTION:The feed water contg. the phosphorus is admitted into an aerobic tank 11 and the raw water subjected to an aerobic treatment is subjected to a solid- liquid sepn. in a settling tank 12. The supernant liquid is released as treated water and part of the sludge is returned to the aerobic tank 11. Part of the remaining sludge is discharged to the dephosphorization tank 13 and the further remaining sludge is discharged as excess sludge to the outside of the system. Part of the feed water is admitted into the tank 13. An anaerobic state is maintained in the dephosphorization tank where the phosphorus in the sludge is quickly released. The waste water contg. high-concn. phosphorus in the tank 13 is discharged to a mixing tank 14 by using a detergent liquid. Lime, etc. are added to the waste water to insolubilize the phosphorus in the waste water in said tank and thereafter the water is subjected to the solid- liquid sepn. in the next settling tank 15. The supernatant liquid thereof is released as the treated water and the sludge is discharged to the outside of the system.
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