Multivariable Process Control System To Treat Municipal Wastewater With Multicomponent

In recent years, with the rapid development of economy and the improvement of people’s living standards,water consumption in China is growing rapidly,which leads to a dramatic increase in the amount of wastewater discharge, and promotes the development of sewage treatment industry in China. Therefore, how to guarantee the high performance and stability of sewage treatment plants and how to make full use of the ability to reduce the pollutant and reduce the energy consumption have become higher requirements of urban wastewater treatment. The wastewater treatment plants in China face problems of high energy consumption and low efficiency. Consequently, the research on the optimization process control of municipal wastewater treatment should be strengthened to solve a variety of problems in the sewage treatment process and management and improve the efficiency of wastewater treatment plant. At present stage of our country, it has great theoretical and practical significance of saving money and improving the effect of sewage treatment.A/A/O simultaneous nitrogen and phosphorus removal process is widely used in wastewater treatment in China with plug flow operation mode. At present, some researches of sewage treatment process control have been done, but the change of pollutant concentration in the process of water treatment is not considered, the concentration of pollutant in the direction of the plug flow is different, it is higher in the front of the process. Therefore, the different positions need to be controlled separately to ensure the full use of the microbial function and reduce the energy consumption.This experiment multi-stage A2/A2/O4 pilot reactor was used, and domestic sewage was used as experimental water. Firstly, the operation variables of the multi-stage A2/A2/O4 pilot reactor was analyzed, the removal rates of COD, NH4-N, TN, TP were 81.87%, 92.57%, 66.37% and 80.06%. The removal of pollutants in the reactor was good and the effluent quality was relatively stable. And then, the changes along the process of pollutant concentration, DO, ORP, p H were analyzed in all levels reactor tanks. The kinetic model of nitrification/denitrification was established for the multi-stage A2/A2/O4 pilot reactor. According to the characteristics A2/A2/O4 process, the control object, control parameters and control variables were determined. The controllable variables of the process include aeration rate, internal return ratio and sludge return flow. The controllable variables were adjusted respectively, and a large number of test data were collected from the reactor to fit kinetic equation. The mathematical models were constructed to lay the foundation for the establishment of the control model.