Sewage Treatment Control System Design And Control Strategy Optimization Research

Due to the non-linear,large lag,and strong coupling characteristics of the wastewater treatment process,it is difficult to ensure stable and efficient operation with traditional methods.Therefore,in view of some problems in the wastewater treatment process in this thesis,several new intelligent optimization control methods have been developed to realize the modeling and prediction of some key wastewater quality parameters and the design of intelligent controllers in the wastewater treatment process.According to the process and control requirements of the wastewater treatment plant,combined with domestic and foreign wastewater treatment status,the thesis first designs a set of PLC based wastewater treatment control system.On the basis of completing hardware configuration,network configuration,monitoring interface configuration and key process control design.Through the configuration of the DDE communication protocol,the data interaction between Win CC and MATLAB is realized,which lays the foundation for the practical application of subsequent advanced control algorithms.Aiming at the difficult problem of on-line monitoring of wastewater effluent quality,a prediction model for the Least Square Support Vector Machine?LSSVM?effluent quality based on an Adaptive Differential Evolution algorithm?ADE?has been established.Because the DE algorithm is easy to fall into a local optimum,a new ADE algorithm is proposed,and the improved optimization performance is verified through performance testing.Then,the global search capability of the ADE algorithm is used to optimize the parameters of the LSSVM,and combined with the actual working conditions,the simulation results show that the ADE-LSSVM prediction model has faster convergence speed and better prediction accuracy than other prediction models.Aiming at the problem that the dissolved oxygen?DO?concentration control accuracy is not high during the aeration process,a Fuzzy Internal Model PID Controller is designed.Firstly,an approximate mathematical model of the aeration system based on DO concentration is established.Secondly,in order to further improve the adaptive ability of the Internal Model PID Controller,a Fuzzy control strategy is introduced to realize on-line adjustment of the filter parameters?.After anti-interference and model mismatch tests,the method has strong anti-interference,high stability,and can effectively solve the problem of model mismatch.After being put into operation on site,it meets the actual control requirements.Aiming at the problem of large energy consumption in the aeration process,according to the relationship between DO concentration and ammonia nitrogen?NH₃-N?concentration,a controller of adjusting DO set-point dynamically based on the NH₃-N concentration is designed.The actual operation results show that the concentration of NH₃-N and the energy consumption of the aeration process are effectively reduced,the quality of wastewater treatment is improved,and the wastewater treatment process can be better controlled by this method.