ACTIVATED SLUDGE TREATMENT METHOD, AND METHOD FOR UPGRADING EXISTING WASTE WATER TREATMENT EQUIPMENT USING SAID METHOD

摘要

The object is to provide an activated sludge treatment method whereby production of excess sludge is brought substantially to zero; and a method for upgrading existing waste water treatment equipment, employing this method. The method includes a step (1) in which sludge (2) produced in a sedimentation tank is supplied to a waste water aeration-conditioning tank for activated sludge treatment; a step (2) in which waste water into which the sludge (2) has been mixed is subjected to aeration-conditioning to bring the oxidation-reduction potential to a positive value, and supplied to a pressurized flotation concentration-separation tank; a step (3) in which the sludge (1) produced through treatment in the pressurized flotation concentration-separation tank is supplied to the bioreactor; a step (4) in which the treated waste water (1) separated from the pressurized flotation concentration-separation tank is supplied to a dilute activated sludge aeration tank; a step (5) in which released water and the sludge (3) produced by treatment in the bioreactor are supplied to the dilute activated sludge aeration tank; and a step (6) in which the treated waste water (2) separated from the dilute activated sludge aeration tank is supplied to the sedimentation tank.

主权项

1. An activated sludge treatment method for treatment of wastewater by a circulation system equipped with a waste water aeration-conditioning tank, a pressurized flotation concentration-separation tank, a dilute activated sludge aeration tank, a bioreactor, and a sedimentation tank, sludge being circulated among the tanks, wherein the activated sludge treatment method is characterized by comprising:
a step 1 in which sludge 2 produced in the sedimentation tank is supplied to the waste water aeration-conditioning tank supplied with waste water prior to treatment; a step 2 in which waste water into which the sludge 2 has been mixed is subjected to aeration-conditioning in the waste water aeration-conditioning tank, to bring the oxidation-reduction potential to a positive value, and the conditioned waste water is then supplied to the pressurized flotation concentration-separation tank; a step 3 in which the sludge 1 produced through treatment in the pressurized flotation concentration-separation tank is supplied to the bioreactor; a step 4 in which the treated waste water 1 separated from the pressurized flotation concentration-separation tank is supplied to the dilute activated sludge aeration tank; a step 5 in which released water and the sludge 3 produced by treatment in the bioreactor are supplied to the dilute activated sludge aeration tank; and a step 6 in which the treated waste water 2 separated from the dilute activated sludge aeration tank is supplied to the sedimentation tank.