| 摘要 |
PURPOSE: A method of removing phosphorus in sewage/wastewater is provided to be able to improve the processing efficiency and to reduce the treatment cost by reducing the amount of the inorganic coagulant which is injected into a third treatment bath while maintaining the concentration of phosphorus in the final discharge water to 0.03 mg/l or less which is the eutrophication prevention standard limit. CONSTITUTION: A method of removing phosphorus in sewage/wastewater uses a water treatment apparatus consisting of a clarifier (10), a primary settling tank (20), a biological treatment tank (30), a final settling tank (40), a coagulation tank (50) and a third treatment tank (60). The method of removing phosphorus in sewage/wastewater comprises the following step: a step of reducing the inorganic phosphorus contained in the biologically treated water by returning the sludge generated in the third treatment tank where inorganic phosphorus is removed by a chemical coagulation reaction to the rear end of the biological treatment tank, precipitating and removing the unreacted coagulants in the final settling tank, and re-using the unreacted coagulants contained in the sludge. The third treatment tank is a filtering tank, a settling tank or a floating tank. [Reference numerals] (10) Detritus tank; (20) Primary settling tank; (30) Biological treatment tank; (40) Final settling tank; (50) Coagulation tank; (60) Third treatment tank; (AA) Raw water; (BB,CC) Sludge; (DD) Transferred sludge; (EE) Surplus sludge (in sludge); (FF) Sludge (including in sludge and non-reacted coagulant; (GG) Inorganic coagulant; (HH) Discharge |
