Sequencing batch reactors

Abstract

A sequencing batch reactor is controlled to provide an effective, efficient treatment of raw waste water. Controls include regular withdrawal of mixed liquor during each cycle of operation. The withdrawal is volumetrically controlled to provide a sludge retention time of 5 to 10 days in the system. This produces a carbon and nitrogen oxydizing bacterial culture with good setting properties. Hydraulic loads in the system are controlled according to liquid levels, while the bacterial processes are controlled by timed sequences. A storm control procedure monitors the influent rate and shortens the cycle times according to the magnitude rate, to increase the system capacity. The system also includes a novel effluent withdrawal system, with a check valve controlled intake about midway up the reactor. This is trouble-free, with the check valve preventing sludge entry into the effluent withdrawal and maintaining prime on the effluent withdrawal pump.

Dependencies are inferred from the claim text.