Research On The Status Quo Of A~2O Treatment Of Rural Domestic Sewage And Optimization Process Research

With improvement of living standards in rural area,rural domestic sewage emissions rise year by year,the social demand for rural domestic sewage treatment in China is increasing,many parts of the country in recent years,successively built integrated rural sewage treatment facilities,but as a result of rural sewage with low chemical oxygen demand/total nitrogen?COD/TN?and great variation coefficient,sewage treatment facilities is often difficult to achieve the desired effect.Therefore,research on a set of integrated sewage treatment facilities that can efficiently treat rural domestic sewage has become a hot spot.According to statistics,the anaerobic-anoxic-aerobic?A²O?integration equipment is widely used in the field of rural domestic sewage treatment in China,but in smaller A²O,is not so easy to choose a suitable fouling resistance into the water pump in order to realize the continuous and stable,the water in the anaerobic,anoxic and oxygen aeration condition and backflow ratio is not easy to control,scale is small in the design of these reasons cause the A²O denitrification and phosphorus removal effect is poor,the low carbon nitrogen ratio effect especially when the water is not ideal.The intermittent aeration sequence batch reactor?IASBR?not only has the characteristics of simple structure and no need to set up refluxion,but also combines the anoxic zone and the oxygen zone in A²O into a reaction zone,and can realize the efficient denitrification and dephosphorization under the condition of low carbon nitrogen ratio by using the alternate anoxic/aerobic environment.Firstly,this paper takes zhejiang province as the research object,through field investigation and a lot of in and out of the water quality test,studied the operation of A²O construction situation,water quality and the factors influencing the running effect of the water,analyzes the different scale of the success rate of sewage treatment facilities,the effective operation rate and removal efficiency of pollutants;Finally,according to the results of field investigation,the removal characteristics of COD,TN,ammonia nitrogen?NH₄⁺-N?and total phosphorus?TP?in rural domestic sewage of different COD/TN by the integrated IASBR with?Reactor no.1?and without?Reactor no.2?fillers were compared,and the change characteristics of pollutants in the period after the optimized operation of the two systems were discussed.The results show that:?1?Poor quality of operation,maintenance and construction of the collection system and the main body of the facility in the research area.The leakage and blockage of the collection system are serious,which affect the quality and quantity of the inlet water.The poor quality of operation and maintenance of facility such as dissolved oxygen control affects the operation effect of A²O facility.?2?Through the sampling show research area 60 rural sewage treatment facilities,found that the regional water quality low COD/TN and COD/TP?1.81 and29.6?,according to?The zhejiang rural sewage treatment facilities for water pollution discharge standard??DB33/973-2015?level of standard analysis different sizes of sewage treatment facilities,it found that:different sizes of sewage treatment facilities influence on COD,TP success rate is not big,and SS success rate increases with the increase of scale of sewage treatment facilities,as high as 60.0%.The effective operation rate of rural sewage treatment facilities of different scales is different.When the scale is 30⁵0 t·d^-1,the effective operation rate of sewage treatment facilities is the lowest,which is 80.0%.When the scale is 50¹00 t·d^-1,the most effective operation rate of sewage treatment facilities is 100%.The removal rate of COD in rural sewage treatment facilities of different scales increases with the increase of treatment scale,and the effect on TN,TP and NH₄⁺-N is not obvious.?3?Under different inlet COD/TN,the removal effects of COD,NH₄⁺-N and TN in no.1 and no.2 reactors were similar.With the increase of COD/TN?from 1.0 to 2.5?,the removal effects of NH₄⁺-N and TN were significantly enhanced.The average removal rates of NH₄⁺-N increased by 12.5%and 7.6%,respectively,and the average removal rates of TN were removed,The rates increased by 31.8 percent and 28.4percent,respectively.?4?After continuous optimization of operation parameters,the TP removal rate of no.1 reactor was gradually better than that of no.2 reactor;The average removal rates of COD,NH₄⁺-N,TN and TP in no.1 reactor were 93.7%,89.0%,81.9%and88.8%,respectively.The average effluent concentrations were 8.4 mg·L^-1,3.9 mg·L^-1,12.9 mg·L^-11 and 0.52 mg·L^-1.The removal rates in no.2 reactor were 93.4%,92.9%,85.3%and 34.1%,respectively.The average effluent concentrations were 8.8 mg·L^-1,3.3 mg·L^-1,10.2 mg·L^-11 and 2.9 mg·L^-1.?5?The process analysis of periodic pollutants shows that the simultaneous nitrification and denitrification and denitrification phosphorus removal can be realized in both sets of reactors,which enhances the denitrification and phosphorus removal effects of the two sets of devices on low COD/TN simulated rural domestic sewage.?6?Along the way,pH and Concentration of dissolved oxygen?DO?can well indicate the reaction degree of nitrification and denitrification.The henomenon of pH"ammonia valley"appeared in the last aeration section of no.1 reactor,indicating that no.1 reactor has space to further increase the aeration volume or extend the aeration time.Compared with no.1 reactor,no.2 reactor has no pH"ammonia valley"phenomenon.