Considering the A2/O process is stable, the sludge settling performance, pollutant removal efficiency is higher, in all also has the function of nitrogen and phosphorus removal in the process, the process is simple, so the final choice of A2/O process. A2/O is the English abbreviation of Anaerobic-Anoxic-Oxic process, it is the anaerobic - anoxic - aerobic biological nitrogen and phosphorus removal process for short, is also in a processing system with an anoxic zone and anaerobic zone, an aerobic zone. The first section of the anaerobic tank, sewage enters the anaerobic reaction zone, at the same time in there from two sedimentation tank return activated sludge phosphorus, release of phosphorus in anaerobic conditions, increase the concentration of P in wastewater, dissolved organic matter by microbial cell uptake and BOD concentration in the sewage down, NH3-N cells synthesis and removed a section, the NH3-N concentration in the effluent decreased, but NO3-N content did not change. In the anoxic tank, denitrifying bacteria using organic compounds in wastewater as carbon source, will return the mixture into a large amount of NO3-N and the reduction of NO2-N to N2 are released into the air, so the decrease in BOD5 concentration, NO3-N concentration decreased greatly, and phosphorus changed little. Therefore, the primary function of the reactor is the removal of nitrogen. In the aerobic tank, the concentration of COD in mixed liquor has been close to the emission standard, in the aerobic reaction zone in addition to further degradation of organic matter, mainly for nitrification and phosphorus absorption, the mixture of nitrate ammonia flow to the hypoxia response area, excessive absorption of phosphorus in sludge by sludge removal.
The A2/O process can be completed at the same time the organics removal, denitrification, phosphorus excess uptake and removed, take off the nitrogen is the premise of NO3-N should be complete nitrification, aerobic pool can finish the function, the complete lack of oxygen pool denitrification function. Anaerobic pond and aerobic pond and phosphorus removal function. In addition, the process also has the advantages of high efficiency, energy saving, and high resistance to shock loading, good water quality. Therefore, it has more extensive adaptability, totally suitable for the actual requirements of the design.
Sewage interception by the coarse grid of large particles, by pumping station sewage is improved, and then through the fine grid to intercept suspended solids, and then through the horizontal flow type grit chamber will most sediment into the A2/O pool, reaction in biochemical pool once again by radial flow sedimentation tank to two remaining sediment settling down, finally after UV disinfection pool reaches the target. In the influent water quality multiplied by a safety factor of 1.1 after the effluent quality to achieve "urban sewage treatment plant pollutant discharge standard after a series of treatment" (GB 189182002 above) in the two standards, finally completed the design requirements.
Keywords: A2Oprocess; domestic sewage; denitrification and dephosphorization    
目录
1 绪论    1
1.1 国内外水污染现状    1
1.2 国内外污水处理现状    1
1.3 设计任务    1
1.4 设计内容    1
1.5 设计依据    2
2 工艺流程的确定    3
2.1 方案的比较    3
2.1.1  A/O工艺    3
2.1.2 氧化沟工艺    3
2.1.3  SBR工艺    3
2.1.4  A2/O工艺    4
2.2 方案选择    4
3 污水处理工艺的设计计算    6
3．1 污水厂进水干管设计计算    6
3．2 格栅的设计计算    6
3.2.1 设计要求    6
3.2.2粗格栅的设计计算    7 A2/O法处理某生活污水的工艺设计+CAD图纸(2):http://www.youerw.com/huaxue/lunwen_7344.html