Key Factors And Model Construction Of Improved A~2/N Process For Nitrogen And Phosphorus Removal

Establishing a healthy water cycle in the city is the fundamental way to realize the sustainable use of water resources.This topic takes domestic sewage as the treatment object,optimizes and improves the A²/N process,solves the contradiction between nitrifying bacteria and phosphate-accumulating bacteria sludge age,reveals a new idea of denitrification and denitrification and phosphorus removal in sewage treatment,and explains the improved A²/N process to simulate the treatment effect of domestic sewage.The research results show that the improved A²/N double sludge process has both good adaptability and operational effect,and the volumetric load is increased to 1.5kg COD/m³·d,which is 2～3 times that of ordinary activated sludge;Operating in a low C/N（3.5～4.5）environment,COD,NH₄⁺-N,TN,and TP can still meet the level A discharge limit of the pollutant discharge standard for urban sewage treatment plants（GB 18918-2002）.The influence of key factors such as the reflux ratio of nitrification liquid,p H,C/N and temperature on the operation of the system was discussed,and the optimal operating point of the operation of the improved A²/N process was clarified;the study showed that when the inlet water flow rate is72L/d,The reflux ratio of the nitrification solution is 110～135%,the influent C/N=4～4.5,the influent p H=7.5～8.0,the temperature is 24～32℃,the removal rate of COD,NH₄⁺-N,TN and TP can be Respectively 97%,96%,74%and 82%;combined with non-parametric test and analytic hierarchy process,it is clear that temperature is the most important factor affecting the decarbonization,nitrogen and phosphorus removal of the system,which is very important for the northern sewage treatment process The guiding significance of C/N,reflux ratio and p H value are significant.Based on the theoretical basis of the material balance and ASM1 model,the anaerobic stage organic matter degradation model and the nitrification model of the aerated biological filter tower are established;the phosphorus removal process of the phosphate-accumulating bacteria is analyzed,and it is clear that both phosphorus release and phosphorus absorption are related to sludge.Concentration is related to time and reveals its quantitative relationship.