Study On Side-flow Technique System Of A~2/O Process To Enhance Phosphorus Removal And Reclaim Phosphorus Resources

With the continuous development of water pollution control in China,the discharge standard of urban sewage is increasingly strict,most of the existing sewage treatment plants in China are facing the problem of upgrading.In view of a series of technical problems brought about by chemical enhanced phosphorus removal in the upgrading of A²/O process sewage treatment plant in China,this project proposes to combine the phosphorus release from anaerobic tank with phosphorus recovery effectively,and to build a side flow process equipment of rapid mud water separation+efficient crystallization phosphorus removal.Based on the rapid mud water separation of the effluent from anaerobic tank,the phosphorus rich supernatant is crystallized and recovered Ensure the return of phosphorus release sludge into the system.Finally,the miniaturized and integrated bypass process is used to enhance the phosphorus removal efficiency of mainstream A²/O process and realize the effective recovery of phosphorus resources.Based on this,relying on the side flow pressure hydrocyclone and the side flow crystal phosphorus removal reactor,and taking the simulated and actual domestic sewage as the experimental water,the separation efficiency of mud water in the pressure hydrocyclone is analyzed through the beaker experiment and pilot test,and the influence law of various water force conditions and operation conditions on the dynamics process of sludge phosphorus release is discussed and the key influencing factors of the fluidized bed crystallized phosphorus removal reactor is analyzed.On this basis,the material balance between the byflow process and the mainstream A²/O process was analyzed,technical parameters of by-pass process are optimized.The treatment efficiency of the byflow process after the linkage was investigated,and the byflow process was linked with the transfer process Through the comparison of A²/O process,the combined process idea of side flow pressure hydrocyclone and side flow crystal phosphorus removal reactor is put forward,in order to provide reference for A²/O process upgrading of sewage treatment plant.The simulation results of FLUENT software show that for a 50 mm diameter micro pressure hydrocyclone,the column height is 80 mm,the cone section angle is5°,the overflow port diameter is 16 mm,and the underflow port diameter is 8 mm,which is more conducive to improving the separation effect of the system.The optimal conditions are as follows:the optimal treatment capacity is 2.6 m3/h,the optimal split ratio is 5%,at this time,the dehydration rate of hydrocyclone can be stable at about 80%,and the sludge concentration multiple is close to 6.The pressure loss is less than 0.1 MPa.The results showed that standing,stirring and centrifuging can promote the release of phosphorus from side flow phosphorus rich sludge,the optimal release time was 8h,4h and 2min respectively;treatment of phosphorus rich supernatant in simulated A²/O anaerobic tank with fluidized bed crystallizer,and the crystallization products were characterized by EDS-SEM and XRD.The optimal condition of the key influencing factors were that HRT 60 is min,the initial pH value of the reaction is10,Mg/P is 1.2.At this time,the phosphorus removal rate of the fluidized bed crystallization reactor was more than 95%,and the phosphorus resources could be efficiently removed and recovered.The results of process linkage show that When the bypass ratio is 30%,the average treatment effect of the system is better,and on this basis,the actual sewage is operated for 30 days.It is found that the average concentration of COD,NH₄⁺-N,TN and TP in the effluent of the system are 36.4 mg/L,1.36 mg/L,2.53 mg/L and 0.43mg/L respectively,and each pollutant index reaches the first class A standard.Compared with the traditional A²/O process,it is found that the start-up of the bypass phosphorus recovery process combination can greatly improve the total phosphorus removal effect of the system,and the actual sewage post-treatment effect is relatively stable,indicating that the bypass phosphorus recovery process has a good treatment effect,which is very necessary for the improvement of the treatment effect of the traditional A²/O process.