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.

MBR classification

The integrated system places the membrane assembly directly within the reactor, extracting the filtrate through suction. The cross-flow required for membrane surface cleaning is generated by air agitation and is located directly below the membrane. The mixed liquid flows upward with the airflow, generating shear forces on the membrane surface to reduce membrane fouling. The integrated membrane bioreactor process is an organic combination of wastewater biological treatment technology and membrane separation technology.MBR Classification

Membrane bioreactors (MBRs) are widely used in the water treatment industry. They are categorized based on their membrane components and operating principles.

Generally speaking, MBRs can be classified as follows:

Membrane separation bioreactors: MBRs are used for solid-liquid separation in wastewater treatment.

Membrane aeration bioreactors: In MBRs, the membrane is used for gas mass transfer, typically supplying oxygen for aerobic processes. This allows for bubble-free aeration in the bioreactor, significantly improving the reactor's oxygen transfer efficiency.

Extraction Membrane Bioreactors (EMBs): Extraction MBRs are primarily used for the treatment of priority pollutants in industry. Selective permeable membranes are used to extract specific pollutants.

Based on the placement of the membrane assembly, MBRs can be categorized as split-type and integrated.

Split-type MBRs separate the bioreactor and membrane assembly. The pressurized mixed liquor in the MBR enters the membrane assembly. Under pressure, the liquid in the mixed liquor permeates the membrane to form the system effluent, while the activated sludge is retained and returned to the bioreactor with the concentrate.

Membrane bioreactors (MBRs) can be categorized as aerobic or anaerobic depending on whether they require oxygen. Aerobic MBRs are generally used for municipal and industrial wastewater treatment. Aerobic MBRs are typically used in municipal wastewater treatment for effluent reuse, while those used in industrial treatment are primarily for the removal of specific pollutants, such as oils and fats.