MBR membrane bioreactor

The membrane bioreactor (MBR) is a novel water treatment technology that combines a membrane separation unit with a biological treatment unit. Using membrane modules instead of secondary sedimentation tanks, the bioreactor maintains a high activated sludge concentration, reducing the footprint of wastewater treatment facilities and reducing sludge production by keeping the sludge load low. Compared with traditional biological water treatment technologies, MBR offers the following key advantages: high treatment efficiency and excellent effluent quality; compact equipment with a small footprint; and easy automation and simplified operation and management. Since the 1980s, this technology has garnered increasing attention and become a research hotspot. MBRs are now used in over a dozen countries, including the United States, Germany, France, and Egypt, with scales ranging from 6 to 13,000 m³/d.

Features

1) High pollutant removal rate, strong sludge bulking resistance, stable and reliable effluent quality, and no suspended solids in the effluent;

2) The membrane bioreactor enables independent control of the reactor's sludge age (STR) and hydraulic retention time (HRT), greatly simplifying its design and operation;

3) The mechanical retention of the membrane prevents microbial loss, maintaining a high sludge concentration within the bioreactor, thereby increasing volumetric loading and reducing sludge load, and providing strong shock resistance;

4) Due to its long SRT, the bioreactor also functions as a "sludge nitrification tank," significantly reducing sludge production, resulting in low excess sludge production and low sludge treatment costs.

5) The membrane's interception effect prolongs the SRT, creating an environment conducive to the growth of slow-growing microorganisms, such as nitrifying bacteria. This improves the system's nitrification capacity, while also enhancing the treatment efficiency and thorough decomposition of recalcitrant macromolecular organic matter.

6) The activated sludge in the MBR aeration tank is not lost with the effluent. During operation, the activated sludge changes with the incoming organic matter concentration, reaching a dynamic equilibrium. This ensures stable effluent and resistance to shock loads.

7) The extensive hydraulic circulation results in uniform mixing of the wastewater, which in turn allows for excellent dispersion of the activated sludge, significantly increasing its specific surface area. The high dispersion of activated sludge in the MBR system further enhances water treatment efficiency. This is incomparable to the larger flocs formed by conventional biochemical water treatment technologies.

8) The membrane bioreactor is easily integrated, easily automated, and conveniently operated and managed.

9) The MBR process eliminates the need for a secondary sedimentation tank, reducing floor space.