Study On The Adaptability Of Treatment Performance Of Urban Wastewater Treatent Plant In Chongli District

With the rapid development of urbanization,the increasing amount of sewage discharge has gradually become an important factor limiting the environment and economic development of cities and towns.The efficient operation of wastewater treatment plants is a necessary guarantee to improve the ability to contain water and alleviate the situation of water scarcity.However,in practice,the operating conditions of wastewater treatment plants are unpredictable,and poor operation can lead to secondary pollution of the effluent environment.Therefore,how to improve the reliability of wastewater treatment plants in actual operation and enhance the treatment performance of wastewater treatment plants has become a hot topic of research nowadays.This thesis took Chongli District Urban Wastewater Treatment Plant as the research object,and clarified the key pollutants with the water quality situation in2021.Based on the system process,a physical model was constructed,and combined with the material balance principle,the organic degradation and nitrification model,biological denitrification model,and biological phosphorus removal model were established in turn,which together form a modified A²O+MBR combined process system model.Based on this research method,this thesis evaluated the treatment performance of the target wastewater plant in design state and status quo operation respectively,explored the range of treatment performance changes under changing adaptive conditions,and finally combined the most unfavorable conditions throughout the year 2021 to analyze its impact on the treatment performance of the target wastewater plant and related suggestions are put forward.The main conclusions obtained from the study are as follows.（1）The data of influent water quality and quantity of Chongli Sewage Treatment Plant in 2021 were analyzed.The seasonal variation of water quality and quantity was obvious,and most of the monthly maximum concentrations of TN,NH₄⁺-N and TP were higher than the designed influent concentration.The key pollution factors of the operation system were pollutants such as N and P.（2）Based on the process flow,pollutant degradation mechanism and material balance principles of the target wastewater plant,the physical model of the process system and the modified A²O+MBR combined process system model were established in turn.The results show that the relative error values of system b COD_eand NH₄⁺-N_ecould be stabilized within 10%;the relative error values could be stabilized within 10%when the SDNR adjustment value used in the model was lower than the typical SDNR value of 0.02.Therefore,the kinetic parameters could better characterize the simulated values and the measured values.Therefore,the kinetic parameters could better characterize the fit between the simulated and measured values,and could be used as reliable parameters to study the treatment performance of the target wastewater plant.（3）Based on the established modified A²O+MBR combined process model,the adaptability of the system performance was evaluated from the design state operation simulation,the status quo simulation,the change adaptability simulation and the combined adaptability simulation,respectively.The simulation results were as follows:（1）The design state simulation results showed that the system treatment performance was good and could meet the design objectives;（2）The status quo simulation results showed that the system treatment performance was good and the actual operation reliability was high when the return flow distribution coefficient in the anoxic tank I and anoxic tank II was 1:2;（3）The status quo simulation conditions of the wastewater plant treatment performance could only meet the current pollution load conditions,and when the influent pollution load exceeded the status quo simulation When the influent pollutant load exceeded the simulated pollutant load value,the effluent nitrogen and phosphorus would exceed the standard;（4）The best internal return ratio operation range was when the return ratio in the anoxic tank I was below 100%and the return ratio in the anoxic tank II was below 240%under the current simulation conditions;（5）When the sludge age of the process system gradually increased under the current simulation conditions,the organic matter degradation and nitrification process would be strengthened,but the excessive sludge age may leaded to the return sludge The sludge age of the system should be controlled at about 25d;（6）When the temperature droped below 15℃under the status quo simulation,the system nitrogen and phosphorus effluent indexed do not meet the discharge standard;（7）The combination of the most unfavorable conditions for the year-round operation of the target wastewater plant was substituted into the process system model,and the results showed that it would not only causeed impact on the treatment system,but also significantly increased the treatment cost.（4）Therefore,it was recommended that the operation of the wastewater treatment plant should strengthen the strict monitoring of the incoming water quality and quantity,and timely monitoring of changes in the concentration of pollutants in and out of the water;the system should be ensured to operate within the best internal reflux ratio;the sludge age should be properly adjusted to stabilize the system operation effect;the carbon and nitrogen ratio of the system should be increased and polymeric aluminum chloride should be added when the low temperature situation occurs in the operation;the extreme influent situation should be responded flexibly by discharging into the accident emergency pool,using intermittent influent mode or adding additional carbon source and phosphorus removal chemicals.