| With the increasing emphasis on ecological environment and energy saving in the context of“dual carbon”,the stable,efficient,low-carbon and fine operation of sewage treatment plants has attracted more and more attention.In this thesis,a sewage treatment plant in northeast China is taken as the research object,and the actual operation status of the sewage treatment system is comprehensively investigated and analyzed.Based on the full analysis of the influent quality of the sewage,the SUMO software is used to construct the operation process model of the sewage treatment plant.Aiming at the typical scenario conditions of normal temperature period(14℃-23.7℃)and low temperature period(5.2℃-14℃)in northeast China,the steady-state model sensitivity parameter adjustment,dynamic data model verification and process optimal operation condition prediction of the improved AAO main process unit are discussed,in order to guide the optimization of the operation parameters of the sewage treatment plant through the model,greatly improve the removal effect of pollutants,reduce the energy consumption and material consumption of the sewage plant operation,and realize the stable,efficient and low carbon operation of the sewage treatment plant.Affected by the low temperature conditions in Northeast China,the effluent TN and TP in the low temperature period of the sewage treatment plant exceeded the standard seriously.Through the characteristic analysis of the influent quality of the target wastewater treatment plant,the influent components were converted into SUMO simulation software to input the component proportion parameters.The average value of the annual operation data of the sewage treatment plant in 2019 was taken for preliminary simulation of the model.The results obtained were quite different from the actual effluent average,and the degree of coincidence was low.The sensitivity coefficient analysis method was used to determine 15 built-in characteristic parameters that significantly affected the operation results of the model.The average values of influent and effluent in normal temperature period and low temperature period in 2019were used as calibration data to adjust the characteristic parameters of the relevant model,and the steady-state simulation and calibration of the model were carried out for the operation results of the sewage plant in normal temperature period and low temperature period respectively.Finally,the accuracy of the model is verified based on the dynamic data of normal temperature and low temperature in 2019.The results show that the simulated effluent value is highly consistent with the actual effluent data,and the relative errors of the effluent water quality indexes(COD,BOD,TN,ammonia nitrogen,TP and SS)are all within 10%.The simulation results can better reflect the actual operation state and effluent results of the water plant.On the premise of meeting the discharge standard of effluent,the model was used to discuss the optimal operation conditions of the process,so as to provide guidance for the efficient,energy saving and optimal operation of the sewage plant.The simulation results show that the optimal operating conditions of the target wastewater treatment plant at room temperature are dissolved oxygen 2mg/L,internal reflux ratio 100%,external reflux ratio 100%,sludge age 20d,PAC dosage 0.08 kg/m~3water;the optimal operating conditions in low temperature period were dissolved oxygen 3 mg/L,internal reflux ratio 100%,external reflux ratio 80%,sludge age 24d,PAC dosage 0.15 kg/m~3water.Under these conditions,the effluent of the wastewater treatment plant can achieve stable discharge throughout the year.Compared with the previous operation of the water plant,the total pollutant emission decreased,but the operation cost decreased significantly.The annual average material consumption cost could be reduced by 1.54%,the annual average energy consumption cost could be reduced by 11.76%,and the annual average economic cost could be reduced by 4.2%. |
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