Sewage treatment by a low energy membrane bioreactor

A new membrane bioreactor (MBR) was developed for treatment of municipal wastewater. The MBR was mainly made up of an activated sludge reactor and a transverse flow membrane module, with an innovative configuration being in application between them. As a result, the transverse flow membrane module and low recirculation flow rate created advantages, such as lower energy consumption and more resistance to membrane fouling. The total energy consumption in the whole system was tested as 1.97 ± 0.74 kW h/m3 (permeate) while using periodical backwash with treated water and backflush with mixed liquor daily, being in the same level as a submerged membrane bioreactor, reported to be 2.4 kW h/m3 (permeate). Energy consumption analysis in the system shows that the membrane module was more energy consuming than the other four parts listed as pump, aeration, pipe system and return sludge velocity lose, which consumed 37.66–52.20% of the total energy. The effluent from this system could be considered as qualified for greywater reuse in China, showing its potential application in the future.