MICROBIOLOGICAL DENITRIFYING AND DEPHOSPHORIZING METHOD OF WASTE WATER

摘要

PURPOSE:To obtain stably good-quality treated water by treating anaerobically the waste water contg. dissolved organic compds., nitrogen compds., and phosphorus compds., and then treating aerobically the waste water in the presence of a carrier wherein nitrifying bacteria are inclusively immobilized. CONSTITUTION:The phosphorus which is discharged into the liquid in a denitrification vessel 2 and an aerobic vessel 3 and the phosphorus contained in the original water are taken in. Nitrifying bacteria which are inclusively immobilized in a carrier 7 are packed in the aerobic vessel 3. The nitrogen compds. in the waste water are oxidized by said nitrifying bacteria to nitrous acid or nitric acid in the aerobic vessel 3. A part of the mixed liquid contg. nitrogen oxide are returned to the denitrification vessel 2, and the nitrogen oxide is reduced to gaseous nitrogen. The remainder of the mixed liquid is charged into a denitrification vessel 4. An organic substance is added into the denitrification vessel 4 from an injection port 9. The mixed liquid is sent into a reaeration vessel 5 to oxidize and remove the residual part of the added organic substance, and aerated. Then the sludge is settled and separated in a solid-liquid separating vessel 6, and the supernatant water is discharged.