Abstract: In an anaerobic membrane bioreactor (“MBR”), a closed anaerobic process tank contains a membrane filter or is connected to an external tank containing a membrane filter. A pocket of biogas accumulates at the top of the process tank. Biogas is taken from the pocket, pumped to the bottom of the membrane filter to provide bubbles to inhibit membrane fouling, and returned to the pocket. Excess biogas produced as the wastewater is degraded is removed from the system and may be used as a product. However, biogas and liquid are maintained in the system at a pressure above atmospheric, for example 10 kPa or more above atmospheric pressure, sufficient to provide at least a material contribution to the transmembrane pressure driving permeation through the membranes. The overall energy requirements of the system may be reduced. Further, with sufficient pressure, suction pumps attached to the membranes may not be required.

Abstract: In an anaerobic membrane bioreactor (“MBR”), a closed anaerobic process tank contains a membrane filter or is connected to an external tank containing a membrane filter. A pocket of biogas accumulates at the top of the process tank. Biogas is taken from the pocket, pumped to the bottom of the membrane filter to provide bubbles to inhibit membrane fouling, and returned to the pocket. Excess biogas produced as the wastewater is degraded is removed from the system and may be used as a product. However, biogas and liquid are maintained in the system at a pressure above atmospheric, for example 10 kPa or more above atmospheric pressure, sufficient to provide at least a material contribution to the transmembrane pressure driving permeation through the membranes. The overall energy requirements of the system may be reduced. Further, with sufficient pressure, suction pumps attached to the membranes may not be required.