| As a new tool, the Activated Sludge Model developed by the International Water Association (IWA) in 1980's has been available in the design, performance administration, nitrogen and phosphorus removal upgrading and the development of new wastewater treatment technology and process, which has been widely used in many developed countries. However, this has seldom been reported in china. In this study, the operating process of a municipal wastewater treatment plant in Shanghai was presented. Taking A/O technology of municipal wastewater treatment as example, mathematical model test was applied to analyse the effect of 14 dynamical parameters of activated sludge model No.1 and A/O process system parameters in effluent wastewater composition. The result shows that the kinetic parameters such as bH,μH,μA, Ks and KNH have great influences on the effluent water composition. Atthe same time ,the result shows that the choosing of sludge age, recirculating ratio, dissolved oxygen concentration and the volumetric ratio of aeration tank and anoxic tank is very important. Simulation result helps to choose the best process parameter.The EFOR system was used to simulate the real operation of Tianshan Wasterwater Treatment Plant. When the default parameters recommended were used, the modeling value of COD and NH4-N was proved to disagree with the measurement. According to parameter influence analysis, good simulation results were achieved through changing of only three model parameters as follows: maximum specificgrowth rate for autotrophic biomass μA from 0.9 d-1 to 0.65 d-1, ammoniahalf-saturation coefficient for autotrophic biomass KNH from 1.0 gN/m3 to 1.3 gN/m3, half-saturation coefficient for heterotrophic biomass KS from 20gCOD/m to 30gCOD/m3.Aiming at increasing the efficiency of nitrogen removal in Tianshan Wastewater Treatment Plant, a choice was made to change the existing aeration basin into biological nitrogen removal process. In this study, two upgrading schemes wereconsidered: First, in the consideration of no higher construction costs, the existing pattern of performance was upgraded into a biological nitrogen removal process-A/O process.Through mathematical simulation of the scheme, the feasibility of this upgrading project was evaluated and the optimum control parameters were obtained. If the influent flow keeps constant, the results showed that the optimum control parameters were: The ratio of anoxic volume to total system volume was 1:3, the dissovled oxygen concentration of aeration basin was 3 mg/L, the recirculating effluent flow ratio was 200%. After upgrading, the effluent COD concentration was hardly influenced, while the effluent TN and Ammonia nitrogen concentration could decrease a lot, the effluent concentration could also meet the emission control standard. Second, another upgrading scheme was put forward in condition that the influent flow rate of the plant keeps on increasing. This project tried to keep the current constructions and equipments unchanged, the plant is upgraded by only augmenting anoxic basin before the original aeration basin. The augmented volume of anoxic basin was obtained by applying the mathematics modeling. The optimum control parameters of this new upgrading process were optimized through the modeling and simulating of the schemes. The results showed that: if the third stage of the existing aeration basin was changed as an anoxic zone and the internal recycle was from the second stage of the existing aeration basin instead of the forth stage ,the ratio of anoxic basin volume to aeration basin volume was 0.5, the recirculating effluent flow ratio was 300%. A very good efficiency of nitrogen removal was obtained if the A/O process was changed into the Bardenpho process.The results of research showed that the EFOR program could simulate the performance of traditional activated sludge process and provide valuable references for directing the biological nitrogen removal upgrading of existing WWTPs, and it is worthy of carrying out a furth...
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