4）进入A2/O生物反应池，该池是去除污水中水体主要污染物的主要构筑物；

   5）进入二沉池，经由二沉池处理，实现泥水分离，部分活性污泥回流，净水流出进入下一处理构筑物，剩余污泥排出：

   6）经由二沉池流出的净水进入消毒氯间，作投氯消毒处理。

   7）前述构筑物中所产污泥进入污泥浓缩池进行污泥浓缩，后经污泥脱水车间形成泥饼，外运掩埋

   8）净水经消毒氯间消毒，达到出水水质要求，最后排入附近河流。

   除了工艺流程设计外，本次设计还计算出各构筑物的详细参数，并进行了设备选型。最后完成厂区平面图、构筑物设计图、高程图等CAD图纸。具体设计计算内容附在下方正文中，各种CAD图纸同样作为附图收录进本次设计。

Design Notes

   When peace and development become the common theme of the world, the social focus will inevitably fall on the issue of "environmental protection"。 Whether it is "peace" or "development" are inextricably linked with the environment。

   The definition of the environment is very broad, pided into two major categories of material and non-material factors。 Substance factors include the existence of all the concrete forms of the atmosphere, soil, water, animals, plants, microorganisms, etc。, and material factors such as concepts, systems, and behavioral norms。 And this design for the object, is one of the important components of environmental protection - sewage treatment。

   It is well known that humans play the role of a consumer in the biosphere material and energy cycle and are the largest group of consumers。 With the improvement of social productive forces, the progress of urbanization, the rapid development of industry, the substantial increase in the level of living material。 Per capita energy consumption and per capita pollution is also increasingly high。 Similarly, in order to support and meet the high consumption level of residents, the industrial level should go hand in hand, the construction of various types of factories and industrial parks is inevitable。 Industrial development and environmental protection seems to have always been a rival, is contrary to the two propositions。 Admittedly, more and more developed industry, means more and more pollution, more and more wastewater。 But we can not choke food, in order to achieve a beautiful environment and completely abandon the industrial development of the secondary industry。 Although the country's and people's awareness of environmental protection and scientific and technological development, industrial pollution ratio is declining, but the total value of pollution is still rising, in the total amount of sewage still occupy a high proportion (about a percentage Of the 49)。 In this situation, the development of improved sewage treatment process, the construction of various reasonable and effective sewage treatment plant has become an urgent task。

   The design task requires the treatment of water for the 20000m3 / d of an industrial park sewage treatment plant water, including domestic sewage and fluorine chemical and metallurgical industry-based industrial wastewater, designed flow of 20,000 m3 / d。 The influent water quality BOD5, COD, SS, ammonia nitrogen, TN, TP were: 250mg / L, 550mg / L, 350mg / L, 30mg / L, 3mg / L。 In accordance with the requirements of water storage, the water to achieve "urban sewage treatment plant pollutant discharge standards" GB18918-2002 Class B emission standards。

   Wastewater treatment plants are still being used in sewage treatment plants around the world。 Large types include activated sludge, aeration biofilter and UNITANK process。 And the most widely used, the most complete technology, the most mature technology, the most reliable equipment, the most successful case was active sludge method。