TREATMENT OF ORGANIC WASTEWATER

摘要

PROBLEM TO BE SOLVED: To separate and recover a phosphorus component in a short time by separating wastewater after aeration-treatment into primary treatment water and sludge, concentrating the obtained sludge and heating the concentrated sludge under specified conditions to release phosphorus and separate into secondary treatment water containing the released phosphorus component and the secondary sludge free from phosphorus component. SOLUTION: Raw wastewater A is fed from an anaerobic treatment tank 7 to an aeration treatment tank 1 to subject to aerobic treatment by an aeration means 12. The aeration-treated liquid is separated into phosphorus component-concentrated sludge and primary treatment water (a) by a solid-liquid separation means 2. The obtained sludge is concentrated by a concentration means 3 to obtain primary sludge (x) and phosphorus component-free separated water, which is discharged together with the primary treatment water (a). The obtained primary sludge (x) is heated by passing through a heat exchanger 11 and then heated at 60-90 deg.C for 10-120 minutes using a heating means 10 in a phosphorus releasing tank 4 to release the phosphorus component. The heated sludge is separated into treated water secondary treatment water) (b) rich in the phosphorus component and secondary sludge (z) by a solid-liquid separation means 5.