| 摘要 |
PURPOSE:To improve economical efficiency by supplying the treated water to the sewage treatment tank after the sludge from which the organic carbon and nitrogen are removed, is flocculated, settled, and removed from night soil. CONSTITUTION:Night soil from storage tank 1 and neary same amount of miscellaneous waste water from storage tank 2 are supplied to mixing-decomposing tank 3. The organic carbon and nitrogen contained in the night soil are removed by means of nitrification reduction by the action of active sludge while the air is supplied from air diffusing pipe 4. At the time, the major part of treated water from mixing-decomposing tank 3 is returned to mixing-decomposing tank 3 through circulating current passage 5. The rest of treated water is supplied to settling tank where the sludge contained in the treated water is settled and separated. A part of the sludge deposited in settling tank 6 is sent to sludge treating facility 7 and the rest is returned to mixing-decomposing tank 3 through current passage 8. The treated water from which the sludge is removed at settling tank 6 is sent to settling tank 10 where minute sludge contained in the treated water is settled and removed by mixing a flocculant. Then, the treated water is returned to sewage treatment tank 11 and the condensed sludge is returned to mixing-decomposing tank 3 through current passage 12. |
