Automation Control System Design Of The Sewage Disposal Plant In YANJIAO

With the rapid development of industrialization in our country, the tendency of water pollution is aggravated year by year, which brings a lot of adverse effects to people’s life. Thus sewage disposal has induced heighten concerns from the government. A large number of sewage disposal plants have been constructed all over the country. The control system of sewage disposal is a complex system of multi-variable, nonlinear, multi-loop, long-time-lag. Designing an automatic, high-reliability and low-cost system will greatly promote the development of China’s environmental protection. We ameliorate the control system according to YANJIAO sewage disposal plant to make the system more efficient, environmental and energy saving.An analysis of sewage disposal process for YANJIAO sewage disposal plant has been made, which is divided into three parts: the predisposal of sewage, the secondary disposal of sewage and the disposal of sludge, the control system was designed with the concept of modular.The semi automation sewage disposal mode used in YANJIAO sewage disposal plant has been analyzed. According to the requirements of fully automatic control, the scheme and procedure have been designed for the control system of the following execution modules: the coarse grids, the sewage lifting pumps, the fine grids, the aerated grit chamber and a sand water separator, the hydrolysis tank and SBR biological disposal pool, the ultraviolet disinfection pool and the power plant reservoir, sludge disposal. Then an overall design for the sewage disposal control system is proposed, which could ameliorate the control mode.PLC software has been selected reasonably. The design of control program is accomplished for the following execution modules: the coarse grids, the sewage lifting pumps, the fine grids and conveyor, the aerated grit chamber and sand water separator, the hydrolysis tank and SBR biological disposal pool, sludge reflux pump and sludge dewatering. At last, the design of main monitoring interface and key devices monitoring interface is accomplished.