Overview With the deepening of China's opening up, China's tourism and real estate development in Punta, luxury hotels and villas where they stand, and high-rise hotels and villas often turn away from the city sewage treatment plant, to bring centralized sewage treatment inconvenience. In order to protect the environment for future generations, successfully developed by Tongji University WSZ-AO series of sewage treatment equipment. The device uses advanced biological treatment processes in the world, set the removal of BOD, COD, NH-N in one, is the most efficient water treatment equipment. It is widely used in sewage treatment luxury hotels, villas and residential areas, replacing the removal rate is very low. Treated effluent can not meet the national discharge standard septic tank. After field application shows, WSZ buried sewage treatment plant is a treatment effect is very ideal and convenient management of devices. Works WSZ buried sewage treatment plant to remove organic matter and ammonia nitrogen pollutants mainly depends on the device AO biological treatment process. Which works at A-level, due to the high concentration of organic wastewater, microbial gas shortage in the state, then the microorganisms and microorganisms, they will sewage decomposition of organic nitrogen is converted into NH-N, while the use of organic matter as an electron donor the NO-N.NO-N is converted to N, but also the use of part of the organic carbon and NH-N synthesis of new cellular material. So not only have a certain Class A pool of organic matter removal function, reduce the subsequent aerobic pool organic load facilitate digestion proceeds, but rely on the presence of high concentrations of organic matter in the raw water, the completion of the anti-digestion, the eventual elimination of nitrogen eutrophication in O level has been significantly reduced due to the concentration of organic matter., but there is still a certain amount of organic matter and high NH-N exists. In order to further oxidation and decomposition of organic matter, while carbonation in digestion smoothly under completion, set a lower organic load of good biological contact oxidation pond at O-level, in the O-level pool mainly aerobic microorganisms and bacteria since oxygen (digestive bacteria), where aerobic microorganisms to decompose organic matter into CO2 and H2O, autotrophic bacteria (digestive bacteria) or the use of inorganic carbon in the air produced by the decomposition of organic matter as raising CO2 sources, sewage NH-N is converted to NO-N.NO-N. O-level pool of water back to the A-level pool provides the electron acceptor by the eventual elimination of anti-digestion of nitrogen pollution is a Class A pool.