Engineering Application And Design Of The Control System For Sewage Treatment Based On PLC Technology

There are mainly domestic sewage and industrial sewage of a petrochemical wastewater treatment plant, In the treatment of industrial wastewater, including COD biological degradation, oxygen, phosphorus and other relatively complex and cumbersome physical and chemical process. Owing to the early construction and the reliance on manual operation of the sewage treatment system, causing security risks and low efficiency, which seriously restrict the development of sewage treatment in the direction of safety, high efficiency and economy. In this paper, aiming at improving the existed problems of the original sewage treatment system and designing a set of PLC automatic control system. The main contents of this paper including:(1) Based on the detailed analysis of the sewage treatment process, aims at the existed defects of the original sewage treatment unit, works out a set of technical scheme of sewage treatment automatic control system, which based on SCADA control system, programmable logic controller PLC and PROFIBUS communication protocol;(2) Completing the software and hardware technology development and design of the sewage treatment control system. The hardware design mainly includes the instrument selection, the SIEMENS PLC design and the communication system design; the software design refers to the software development of PLC slave computer and master computer, including the PLC control base station of pretreatment stage, biochemical reaction stage, follow-up treatment stage and kingview software of the sewage treatment system;(3) Using the classical PID control theory and grey prediction model to adjust the pH value of wastewater, and uses SIMULINK module in Matlab to simulate the electric machinery and put it into practical engineering application, improved dosing pump in an ideal working condition and sewage PH value is well controlled;(4) Carrying out the field installation and shakedown test of the sewage treatment automatic control system, improves the level of automation eontrol, achieves the PLC control system of remote monitoring, ensures the safety of the operator, and enhances the technical management level of sewage treatment, which has good environmental benefits and social benefits.