Study On Optimizing The Effect Of Nitrogen And Phosphorus Removal In Laminated Water Tank Sewage Treatment Plant

In recent years,with the development of agricultural modernization and urban-rural integration,the economic and cultural level in rural areas has been greatly improved.While improving people's lives,the production of domestic sewage will increase with it.However,China just put the focus of water pollution control on the city.Due to the lack of policy reliable and financial support,the majority of rural areas lack perfect sewage collection network and treatment facilities,and most of the domestic sewage is discharged directly to the nearby water body without treatment.Pollutants such as organic matter,pathogenic microorganism,nitrogen and phosphorus in sewage also enter the receiving water with sewage,which makes the pollution of nearby rivers and lakes more serious,and even threatens the drinking water safe of the villagers.The report of the Nineteenth National Congress of the Communist Party of China pointed out clearly that in order to build a new countryside with"ecological livability",the problem of ecological rural ecological civilization and construction environment renovation has become an important part of the construction of new countryside,and the treatment of rural domestic sewage has become an important link of ecological environment renovation.Therefore,speeding up the development of sewage treatment technology adapted to rural areas and improving the rural ecological environment has become an urgent problem.Because the level of economic and cultural development in rural areas is relatively backward and the sewage collection pipeline network is not perfect,it is appropriate for rural areas to adopt the technology of simple decentralized domestic sewage treatment with low investment cost of capital construction,local collection and local treatment and simple operation and maintenance.The laminated filter tank type sewage treatment device emerges as the times require,because it has the advantages of good removal effect,small occupation area,less capital investment cost,simple operation and so on,so it is suitable to be popularized and operated in the vast rural areas.The experimental study is carried out from the following aspects,such as the filling mode of matrix filter material,the optimization of the whole system structure,the optimization of operation parameters,and so on,and it can provides a reference for the subsequent practical engineering application.First of all,this paper studies the filling mode of filter media,and takes simulated domestic sewage as the research object,and investigates zeolite,fly ash ceramsite,shale ceramsite,activated carbon and their effects to expanded vermiculite layered loading and mixed loading on nitrogen and phosphorus removal efficiency of the system.The results showed that the nitrogen and phosphorus removal efficiency of the system was the best when the five kinds of media were packed in different layers,and the average COD_Cr,NH₃-N,TN,TP removal rate was 91.06%,84.17%and80.03%,97.50%respectively.Then,this paper studies the overall structure optimization of sewage treatment system.The effects of three kinds of baffle height?20mm,40mm,60mm?and three kinds of bottom slope?3°,6°,9°?to the nitrogen and phosphorus removal of the system were investigated by taking simulated domestic sewage as the research object.The results showed that:when the height of the baffle plate is40mm and the slope of the bottom surface is 3°,the nitrogen and phosphorus removal efficiency of the system is the best,and it is the least likely to appear the phenomenon of matrix filter material clogging,The average removal rate of COD_Cr,NH₃-N,TN,TP reached 90.24%and 82.78%,81.15%,97.32%respectivelyFinally,this paper optimizes the operation parameters of sewage treatment system,and investigate the effects of influence mode and hydraulic load on the nitrogen and phosphorus removal efficiency of the system.The results show that the system has the best nitrogen and phosphorus removal efficiency when the intermittent influence mode is adopted.The average removal rate of COD_Cr,NH₃-N,TN,TP was 90.46%and 88.88%,81.60%,97.06%,respectively.When the hydraulic load is 0.5m³/?m²d?,the nitrogen and phosphorus removal efficiency of the system is the best.The average removal rate of COD_Cr,NH₃-N,TN,TP reached 91.12%and 93.79%,87.82%,97.45%respectively.