The Design of Control System for Sewage Treatment Based on PLC

The main aim of this paper is to improve the control efficiency of the sewage treatment system, by analyzing the various control parameters of sewage treatment system and comparing different ways of automatic control, Siemens S7-200 Programmable Logic Controller(PLC) is applied to the system. We designed the control flow charts of coarse grid and dewatering system, compiled the total manual program and automatic control program of aerated grit chamber by using STEP 7-Micro/WIN 32 software, and realized the related equipment automatic control in the sewage treatment system which can run the coarse grid machine that runs for 20 minutes and stops for 2 hours alternately et cetera. The results show that the controllability of sewage treatment system is enhanced and the efficiency is improved.