Aquatech Enhanced Membrane Bioreactor (Aqua-EMBR)

Aquatech Enhanced Membrane Bioreactor (Aqua-EMBR) system consists of an activated sludge extended aeration biological treatment process and an Ultrafiltration (UF) membrane system for the separation of activated sludge from treated effluent. Aqua-EMBR is an external MBR system. The UF membrane is positioned outside the bioreactor tank, rather than submerging the membrane in the bioreactor tank or the downstream membrane tank. The UF membrane modules are arranged vertically and are aerated continuously at the bottom. Continuous air injection is for the scouring inside of the modules to sustain the design permeate flux and also to drive the mixed liquor recirculating flow back to the aeration tank. Mixed liquor is thus transported via an "air lift pump" through the module, while the membrane feed/recirculation pump is only used to overcome the hydraulic losses and maintain a relatively constant flow of mixed liquor through the membrane. This innovative design reduces much of the feed pumping energy requirement and enables Aqua-EMBR system to consume lower energy than other competing submerged MBR systems. Permeate from the membrane modules is collected by permeate pump similar to the submerged membrane system. As an "insideout" permeate flow system, a combination of forward flushing (with recycle mixed liquor), draining and periodic backwash & in-line chemical enhanced backwash (with permeate) is used to maintain the design permeate flux and control the membrane fouling. Because no membrane components are submerged in the biological mixed liquor, it is possible to operate and optimize the biological and membrane systems independently.