First, several microporous aerator aerator compare the role of biological pool in: providing microbial growth, reproduction needed oxygen, biochemical reactions and to maximize reach sewage mixed aerobic microbial substances and in contact with the best results . Several common aerator functions and features comparison: two, the current situation an aerator sales market, due to the late start of the domestic industry, specializing in systems research, development and application of a combination of manufacturers, suppliers, domestic few, generally do not have the system of scientific research, production, application, information feedback, improve the mechanism, it has a considerable advantage on material quality foreign products. For example: Foreign diaphragm normal life of up to 5-8 years or even longer. 2, the supplier and the product design department at the technical convergence on system performance are still a considerable distance, often resulting in the product can not be fully utilized. For example: EPDM membrane developed only recommended for municipal sewage, silicon nitrile synthetic membrane (silicone) is recommended for oily wastewater, urethane diaphragm (URETHANE) is recommended for chemical sewage, etc., made the film a single species, three EPDM diaphragm (EPDM) is not quite pass the recipe, but common to all kinds of waste water treatment projects. 3, some domestic inferior products, the customer misleading. For example: there are individual products within a few months that the normal use of the diaphragm is damaged, the situation deteriorated appear. 4, operation, maintenance, improper one-sided understanding of the product. For example: When debugging a small sewage water station, just submerged aerator aeration systems that work with high-pressure air volume, leading to membrane rupture. 5, by the traditional concepts, followed the same industry and put into operation early aeration type copy, make some superior performance products can not effectively promote the use of aeration. All these reasons, the uniform is easy to confuse a correct understanding of the user's choice of biological pond aerator developed countries, although a wide variety of patterns, overall, in recent years, large-scale sewage treatment projects chosen diaphragm aerator main diaphragm aeration especially the most popular tube diffusers and achieved good results. Domestic sewage industry has a certain reference. Third, stress analysis microporous membrane aeration aerator diaphragm due to different force structures are very different, according to the "little sag theory", disc diaphragm, if the deformation is zero after inflation, its tensile stress of the diaphragm is infinity. Therefore, pressure diaphragm deformation, high pressure deformation, corresponding stress is also large. Meanwhile, the same pressure, the diaphragm aerator different configurations produce different internal stress.