Design And Implementation Of The Sewage Treatment Monitoring System

In recent years, with the rapid development of the national urbanization, industrialization,a lot of life and industrial wastewater discharge，leading to the our country’s existing waterresources, the sharp decline of water quality，water pollution is becoming increasingly serious,and seriously endanger people’s physical and mental health, so the sewage treatment, moreand more get the attention of the society. Sewage treatment not only can achieve the waterrecycling, conserving water resources, but also can reduce the sewage to secondary pollution.In order to improve the efficiency of wastewater treatment and economic benefits, design a setof effective monitoring system is necessary. This paper takes GuangDong JieXi countysewage treatment plant automatic control system project as the background, introduces thewastewater treatment plant distributed control system (DCS) overall design andimplementation.JieXi wastewater treatment plant uses the traditional A2/O process, the design of thesewage treatment capacity of30,000t/d, the main component of sewage for domestic water.According to the characteristics of the Sewage Treatment Plant process and controlrequirements, DCS design for a typical three-tier network architecture: field layer, controllayer, and management. The field layer by the online instrument and mechanical equipmentstructure, realize data acquisition and equipment is carried out; Control layer by the PLCcabinet, complete data processing as well as the automatic control; Management are mainlylocated in the central control room, monitoring the whole system and remote control.The system uses the SIEMENS company series S7-300PLC for controller, combinedvarious online instruments to complete the detection of the effluent quality (such as: PH value,COD value), according to the sewage treatment characteristics of the sub-processes anddevice control requirement to complete control of field devices; PC monitoring systemprovided by Toshiba company TOSVIEW configuration software development, staff throughthe monitoring system can remote control of the wastewater treatment plant, at the same timethe system is also designed reporting features for the late staff analysis.For the sewage treatment process large time delay, nonlinear and strong interference, it isdifficult to establish an accurate model of the sewage treatment process control. By analyzingthe mechanism of the sewage treatment process determine the DO, the influent COD, theMLSS and ORP and the relationship of the effluent COD, the establishment of a predictivemodel based on GRNN. Experimental simulation, we achieved very good results. Laid foundation for future intelligent wastewater treatment plant transformation, and technologyupgrades.This system has been JieXi sewage treatment plant operation for nearly a year andrunning effect is good, the water quality meet the national standards, improve the workefficiency, and to achieve the expected purpose.