| For a long time the design and operation of biological wastewater treatment structures are mostly based on empirical data to carry out. Is due to the geographical location and environmental difference,so that after the completion of the sewage treatment plant service is not very good in the local city. In order to improve China's sewage treatment plant construction efficiency, improve management level, ensure the effluent reaches the standard, reduce energy consumption and cost, the application of activated sludge model to actual wastewater treatment plant operation, as much as possible to reduce the application threshold and limitations of the modeling system, formed a scientific and systematic solution is essential.In this paper, the biological treatment process of a wastewater treatment plant in Xi'an was taken as the research object. The construction period of the project is simulated (including design,debugging and operation) using ASM2d model proposed by IWA,and based on WEST software platform. Also the problems in the simulation process are analyzed, solved and optimized.To simplify the simulation process, and to provide support for the application of the activated sludge model to the actual project.In the engineering design stage, according to the "Feasibility Study Report" and "Preliminary Design" information of different process scheme, the operation parameters and the activated sludge model parameters of the process were analyzed and determined. To help build generalized model for process schemes, and simulation results of process schemes under adverse conditions are analyzed and evaluated. The results show that the scheme two "Modified A2/O+MBR" has a better performance. To solve the problem of ammonia nitrogen instability in effluent and risk of TP exceeding under low temperature and COD loading conditions.We set up a pre reaction zone and multiple-influent control, the modified scheme is simulated to determine the optimal parameters of the pre reaction zone and multiple-influent is 1500m3 and 0.5-0.7.During debugging phase, correct optimization model size and operating parameters according to completion project. After sensitivity analysis of influent quality components, based on the measured influent samples, the key parameters of influent components were determined,and the influent parameters were adjusted. Sensitivity analysis to determine the 7 key parameters of great influence on the model(S_Alk_In, F_TSS_COD, f_S_A?f_S_F, f_S_NH,f_S_PO and f_X_H) and 5 conventional influent quality (COD, NH3-N, TN, TPandSS). The 7 key parameters need to be calculated by using the model related components. Through the experimental measurement COD, CODf, SS, SA, XH,TN, SNH4, TP, S, P04, SALK and TSS 11 components, the calculated values of key parameters S_Alk_In, F_TSS_COD, f_S_A, f_S_F,f_S_NH and f_S_PO were 32, 0.83, 0.19, 0.39, 0.72, 0.43, and 0.13, respectively.The model was applied to simulate the sludge addition batch culture scheme and continuous flow culture scheme. Meanwhile simulation results were evaluated using sludge concentration and incubation time, showed that continuous flow culture debugging cycle is longer, but has better sludge performance, and batch culture is just the opposite. In the end, the two methods are combined to be used in practical debugging, which can not only shorten the debugging time,but also get a good activated sludge. Applying the model to optimize the operating parameters of the trial operation stage, the optimal operating values of 5 operating parameters(multiple-influent ratio, internal flow of aerobic tank, internal flow of anaerobic tank, internal flow of anoxic tank, waste sludge) are determined. The optimization results are used in the trial operation of the actual wastewater treatment plant, and the results are similar to the simulation results, the optimization effect is ideal.In the operational phase, the sensitivity analysis of the activated sludge model parameters(kinetic parameters and stoichiometric coefficients) was carried out, by adjusting the key parameters the model is calibrated and effectiveness verified under steady-state conditions. The dynamic inflow and effluent data for 10 days were obtained by daily variation curve and interpolation method, with which calibration and validation of the model are carried out under dynamic conditions.The existing phosphorus removal and energy consumption problems were solved and optimized using the validated model.The biological phosphorus removal function was enhanced by adjusting the residence time of the reactor, the amount of sludge and the flow rate of the mixed liquid. the simulation results indicate that increasing the volume of anaerobic tank,reducing the volume of aerobic tank, ensure that nitrogen effluent standards and appropriate to increase the waste sludge, reducing or shutting down the flow rate of anaerobic zone can effectively enhance the biological phosphorus removal. And the simulation results of auxiliary with chemical phosphorus removal by adding PLAC showed that using of low dose 1.73m3/d can meet the daily requirements. After the energy consumption of the model is estimated, and overall cost is defined, the relatively high proportion can be optimized by feasibility. In the case of meet the usual water standards to appropriate reduce internal reflux, the simulation results show that the pump energy costs than the full return case is reduced by 28.6%, the total operating costs reduced by 16.3%. Aeration can be controlled by the sensing system to meet the effluent standards, so that reduce the amount of aeration and reduce operating costs. The simulation results show that the energy consumption of aeration is reduced by 25.6%. |
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