Modeling And Simulation Of The Actived Sludge Process For Municipal Sewage Treatment System

Computer simulation technology is an effective method in the research of the activated sludge process for sewage treatment system. The activated sludge models released by IWA (International Water Association) have found wide applications at home and abroad. Thus, this paper is on the basis of ASM1, and its study employs computer simulation technology.First, in order to take the phosphorus removal related processes into account as well, this paper puts forward the IASM1 (Improvement of Activated Sludge Model No.1) on the basis of ASM1, which combines the functions of carbon removal, nitrogen removal and phosphorus removal. Meanwhile, the proposed IASM1 is certified with BSM1 (Benchmark Simulation Model No.1) released by COST (European Co-operation in the field of Scientific and Technical Research) and ASM2d released by IWA with respect to the steady state of the carbon and nitrogen removal process and the phosphorus removal process, respectively. Furthermore, using the practical influent and effluent data of two sewage treatment plants in Beijing and Xi’an from November lth to November 30th in 2014, the proposed one is verified with respect to its dynamic process.Second, to improve the overall accuracy of the proposed model, the parameters of the proposed IASM1 are optimized by SVM method. Since the number of the proposed IASM1 parameter is as large as 40, to enhance the optimization efficiency, four parameters (YH、μA、KH、bH) having relatively greater influence on overall accuracy of the proposed IASM1 are found using relative sensitivity analysis method. Then, the overall accuracy of the proposed model can be effectively improved after optimizing these four parameters presented above.Third, the control strategy of the sewage treatment plant is designed based on IASM1. As the most power-consuming systems in a sewage treatment plant, a blower aeration system accounts for 50%-60% of the total power consumption of a sewage treatment plant. To reduce the power consumption in a sewage treatment plant, a simple adaptive control strategy for the blower aeration system is presented in this paper. It consists of a manipulated variable compensator and a aerobic tank DO concentration control system, in which the blower employs frequency control. And the manipulated variable is the rotate speed of blower. This control strategy can significantly reduce the power consumption and operating cost.Finally, on the basis of these three researches presented above, its software is designed based on the object-oriented concept and utilizing UML language. Following this design method, an application software utilizing C++ language and based on VS2010 platform is developed. Simultaneously, using Quest 3d as the three-dimensional display software, the sewage treatment process can be displayed in real time. This software can be connected with external controllers acting as the controlled object. Besides, it can be the learning tool for students and professionals related to sewage treatment.