The Design Of Automatic Control System For Domestic Sewage Treatment

With the rapid development of science and technology,industrial production blossom everywhere,and the pollution of the environment has become more and more serious.In the production of human life,a large number of pollutants will be discharged,and water pollution is the most obvious.If the sewage is discharged freely and without treatment,the living environment of human and animal and plant will be polluted and endangered.The domestic sewage treatment system can effectively deal with domestic sewage,and it is the main means to control domestic sewage.In this paper,the automatic control system of domestic sewage treatment system is designed to improve the efficiency of the system.First of all,the types and treatment methods of domestic sewage are discussed.A set of three stage sewage treatment system is designed,including water inlet system,sand removal system,biochemical pond system,sedimentation system and sludge dewatering system.In the design,we analyze all kinds of controllable parameters in the system,study the commonly used control methods,and consider the performance and cost of the system in actual application.Finally,SIEMENS S7-200 PLC and S7-300 PLC are chosen as the core of the system control.According to the ProfiBus-DP communication scheme,the network communication system is built.The S7-300 PLC is the main station and the S7-200 PLC is the sub station.The information transmission efficiency of the master slave station is 1.5Mbps.In this paper,the information communication program of the master station,the upper computer and the 5 sub stations is designed to realize the interaction of the control information of each part.The automatic control process of the design,use STEP 7-Micro/WIN32 software to write a manual control program and manual conversion processes such as aeration,and the thickness of grid,lifting pump,oxidation ditch aeration 7 automatic control subroutine,the process realizes automatic control.The monitoring part adopts Kingview software and real-time monitoring system.It designs 12 monitoring interfaces,including the start interface,the operation monitoring interfaces,the alarm interface and the historical trend,so that the automatic control system of the domestic sewage is in the real-time monitoring state.