Membrane bioreactor, process and aerator
Membrane bioreactor, process and aerator
US Patènt # 6863817
| Invèntors: | Liu; Minggang (Burlington, CA); Husain; Hidayat (Brampton, CA); Cote; Pierre (Dundas, CA); Pottinger; Ian (Burlington, CA) |
| Assignee: | ZENON Environmental Inc. (Oakville, CA) |
| Appl. No.: | 309819 |
| Filed: | December 5, 2002 |
ABSTRACT
A reactor has an aerobic tank, an anoxic tank and a sealed membrane tank with conduits for circulating mixed liquor between them. Permeation starts when the mixed liquor reaches a high level and stops when the mixed liquor reaches a low level. A sensor, for detecting the mixed liquor level, may stop and start permeation. Pressure builds in the membrane tank when membrane air is on. Transmembrane pressure is also provided by gravity flow or siphon. Membrane air generates an air lift which drives the mixed liquor circulation. The total amount of air provided by an air source is divided and varied in time between the membrane aerator and the process aerator. The process aerator acts as a screening inlet to the conduit to the membrane tank. Chemical maintenance cleaning is provided by gravity flow.
FIELD OF THE INVÈNTION
This invèntion relates to a wastewater treatment process or apparatus, to a membrane bioreactor, to an aerator and to a method and system for treating home, multi-residential, commercial, institutional or industrial wastewater such as black or gray water.
BACKGROUND OF THE INVÈNTION
Currently, many small wastewater treatment systems use a septic tank, followed by a septic field for final purification and discharge. Increasingly, this method is becoming unacceptable because of the low level of treatment achieved, frequent failures and high cost of reconstruction, contamination of streams and groundwater, and the requirement for large land area to establish septic fields.
Japanese publication 2000-028675, German application DE 198 07 890 A1 and PCT publication No. WO 00/37369 describe wastewater treatment systems using membranes.
PCT Publication No. WO 00/21890 describes a cyclic aeration system.
Japanese publication JP 2002-066261 describes a device to catch fibrous foreign substances.
