Study On Pressurization-agitated Purification Tank Treating Domestic Sewage

With the improvement of people’s living standard,domestic sewage contaminants become higher,increasing the difficulty of wastewater treatment.Considering factors such as cost,treatment efficiency and operation,in view of the population spread and widely distributed areas,generally using the septic tank and purification tank to treat domestic sewage.But because of low efficiency for anaerobic tank without mechanical stirring,the treatment efficiency was not ideal.To solve the above problems,in this study,we put forward the purification tank with pressurized agitation,in which air pumped into the anaerobic tank making water stirred,to increase sludge and water mixing and improve the treating efficiency.In this paper,two purification tank(A and B)which have same principle but different structures were used.The result of flow experiment showed the feasibility of purification tank on structure(volume utilization),and it is concluded that agitation can weaken the short flow phenomenon,reduce the water dispersion.The simulation models were made using MATLAB/Simulink and the results indicated that the increase of agitation frequency make purification tank close to the Continuous Stirred Tank Reactor.In this paper,by treating simulated wastewater with low COD concentration and high COD concentration,we explored the influence between agitation frequency and treating efficiency.The results showed that,with influent COD concentration was 1500mg/L,ammonia nitrogen was 20mg/L,the purification tank A had good treatment efficiency with high agitation frequency(COD removal rate was 77%,ammonia nitrogen removal rate was 97%).However,with the increase of stirring frequency,the treating efficiency of purification tank B rose in the first and then decreased,the optimal treatment effect of COD removal rate was 70%,ammonia nitrogen removal rate was 85%.In this paper,by treating domestic sewage,we found the difference between tank A and B in treating efficiency.The experiment results showed that for sewage with high COD concentration,without preprocess by septic tank,the COD average removal rate of tank B was 97%,which decrease average concentration from 7607 mg/L in inflow to 500 mg/L below in effluent.As for the sewage pretreated by septic tank,COD average concentration of tank A in inflow was 1989 mg/L and in effluent was 50 mg/L below.Treating decentralized wastewater with high concentration and great fluctuation,the pressurization-agitated purification tank has great purification efficiency.Moreover,its simple processing and operation management making good development potential.