Membrane bioreactor unit and process for treatment of domestic sewage

The invention discloses a membrane bioreactor unit for treatment of domestic sewage. The membrane bioreactor unit comprises: a reactor, which is filled with aerobic sludge, wherein the bottom of the reactor is connected with a sewage conveying pipeline; a stirrer, which is arranged in the reactor; a first membrane group and a second membrane group, which are arranged in the reactor and respectively located on both sides of the stirrer, wherein the upper and lower ends of the first membrane group and the second membrane group are respectively connected with corresponding external water suctionpumps and air blowers through corresponding membrane modules and pipelines, and each of the pipelines is provided with a valve; two baffle plates, which are respectively arranged between the stirrer and the first membrane group and between the stirrer and the second membrane group, wherein a first membrane group zone, a stirrer zone and a second membrane group zone are sequentially communicated with each other; and a sludge lift pump. The membrane bioreactor of the invention utilizes an aerobic MBR to treat domestic sewage, and realizes simultaneous effective removal of three pollutants, i.e.,organic matters, ammonia nitrogen and total nitrogen; and at the same time, an intermittent aeration system inside a membrane is employed to solve the problem of blockage of a membrane system, so theservice life of the membrane is prolonged.