Research And Design Of Wastewater Treatment Plant Automatic System

As a crucial infrastructure project for the development of city, to promote highly automatic and intelligent control system application in wastewater treatment not only reduce the emissions of pollutants, but also could sharp improve the level of wastewater treatment.In this paper, we take the control system of one wastewater treatment plant as our research subject, and we focus on the precise aeration control system of bio-reaction tank.Automatic-control systems in wastewater treatment plant play an important role to operate complex production process safely, continuously and stably. It can minimize the operating and maintenance costs, and effectively reduce safety risks that caused by man-made factors as well. Therefore, it is very urgent to design advanced automatic control systems for wastewater treatment plant. According to the influent quality and effluent discharge standard of the wastewater treatment plant, the A2 O process is adopted in wastewater treatment. According to the analysis of running model of the critical process, which is aeration system in bio-reaction tank, the precise aeration control system is adopted.First, the automatic process-controlling program in the precise aeration system in A2 O wastewater treatment tank is investigated primarily, which is based on the volatility and time-varying of influent load, high energy consumption of aeration, the quality indexes of effluent was not up to the standard and so on. According to the implementation and operation of precise aeration system, the closed-loop control among blowing, aeration pipes,valves-regulating and oxygen-dissolved has been realized, and which can achieve a bio-reactor aeration demand from the aeration source. In this project, blowing energy could be reduced effectively, and discharge water quality could be improved. It has an active meaning to reduce the energy loss in the wastewater treatment plant.Second, the control targets of wastewater treatment plant have been settled by analyzing treatment process and its features. The control requirements were analyzed and distributed automatic control scheme was designed which based on PLC distributed control system. The main frame of this system is composed by the central control station, the fieldcontrol station and the detecting instruments, and the communication between the different layers is carried out by different means. Then, the entire automatic control system of the wastewater treatment plant has been basically built.Finally, compared with other traditional biological reactor control systems, it can enhance the intelligent control level, which means it could optimize control system and reduce operating costs. So, the automatic control system would have well prospect in the wastewater treatment plant.