MBR is a new waste water treatment technology combining effective membrane separation technique and activated sludge process. Due to membrane units directly immerse in activated liquid mixture, there is no need to built a special secondary sedimentation tank. Compared with conventional biochemical water treatment, MBR has high treatment efficiency and good permeating water quality. MBR system, with small floor space, is easy to achieve automatic control, convenient operation and management. On the one hand, the membrane intercepts the micro organism in reaction tank, increasing the density of the activated sludge and leading to more quickly and completely degrading of sewage; On the other hand, thanks to the high filtering precision, the product water quality can be assured. As an advanced and efficient wanter treatment system, MBR can address the ever growing needs of industrial and domestic sewage treatment capacity, and also tremendously improve the water quality after deep treatment.