Study On Simulation System Of Anoxic-Oxic Nitrogen Removal Process

Activated sludge process is frequently used in municipal wastewater treatment plants, but the design and operation of the plants are still highly dependent on personal experience. Based on this reason, International Water Association (IWA) proposed Activated Sludge Models (ASMs) which described the phenomena and essence of the removal process much deeply. ASMs are important tools in academic study and application in waste water treatment field.Firstly, we chose ASM1 which was used successfully as the model platform after looking back the history of the activated sludge models. This research set up a simulation system of Anoxic-Oxic nitrogen removal process with modeling methods of IWA and Visual Basic computer software. By comparing to third-party data, the simulation results showed that the modeling was credible.The sensitivity analysis of related parameters on chemical stoichiometrics and on biochemical kinetics demonstrated that the sensitivity of different parameters varied greatly. Among stoichiometric parameters, Y_H was most sensitive to the MLSS and COD of aerobic tank, added up to 141.23% and 137.21%. The sensitivity of b_A andμ_A to NH₃-N peaked at 108.97% and 107.39%, while the sensitivity of k_h andμ_A to TN peaked at -45.64% and -44.54%. There were about half of the parameters which were insensitive to simulation results, therefore characteristic parameters could substitute for these parameters when simulating.Batch OUR respirometric experiment was conducted to determine the effluent of primary clarifier and Y_H of aerobic tank's sludge in Sitang wastewater treatment plant in Shanghai. The stable value of Y_H was 0.72 which was a bit bigger than the characteristic value. COD of Primary Clarifier in Sitang wastewater treatment plant were about 200mg/L. About 40%～60% of the COD were X_S; about 10%～40% of the COD were X_I which varies frequently; about 10%～20% of the COD were S_S; about 6%～12% of the COD were S_I.Experimental data of Sitang wastewater treatment plant were used to calibrate the model. The calibrated model was applied to simulate steady-state of the A/O process in Sitang wastewater treatment plant, and the practicability was confirmed.