Research On Construction And Application Of Automatic Sampling And Monitoring System For Water Quality Of State-controlled Pollution Sources In Zhenjiang City

Recently,the public’s awareness of environmental protection has enhanced and their demands on environmental management have become higher and higher.Meanwhile,the frequency and scope of monitoring on pollution sources for enterprises by environmental managing departments are also increasing year by year.Currently,there is a contradiction between the increasing pressure of environmental monitoring management and the shortage of personnel and supervision ability in our country,which requires the establishment of an automatic sampling monitoring system for pollution source monitoring and management.Therefore,how to establish a scientific,reasonable and effective automatic monitoring system for pollution source,and to curb the illegal environmental behaviors of automatic monitoring equipment such as data fraud and illegal disposal,which is one of the difficult problems faced by the environmental protection departments.This paper aims at the water quality monitoring and management of the state-controlled pollution sources in Zhenjiang city.Firstly,the state-controlled pollution sources in Zhenjiang city were investigated and analyzed,and then an automatic sampling and monitoring system for water quality was established and applied to the water quality monitoring of the state-controlled pollution sources in Zhenjiang city,so as to provide a reference for the automatic sampling and monitoring management of the urban pollution sources in our country.The main conclusions drawn are as follows.1.An investigation was conducted on the pollution sources of Zhenjiang City.There are 29 state-controlled pollution source enterprises in Zhenjiang City,including21 sewage treatment plants and 8 other production-oriented enterprises.Nine of the29 enterprises are key pollution source enterprises,of which Zheng Runzhou Sewage Treatment Plant,Jindong Paper（Jiangsu）co.,ltd.,Dagang Sewage Treatment Plant and Jiangsu Thorpe（group）Co.,Ltd.are typical representative enterprises.2.Based on the current situation of state-controlled pollution sources in Zhenjiang city,an automatic sampling and monitoring system for water quality of state-controlled pollution sources was established,which consists of two parts,one is an automatic sampling system and the other is an automatic monitoring system.3.The water quality automatic sampling monitoring system was installed in 29state-controlled pollution source enterprises in Zhenjiang City,and four representative enterprises were selected（Zheng Runzhou Sewage Treatment Plant,Jindong Paper（Jiangsu）co.,ltd.,Dagang Sewage Treatment Plant and Jiangsu Thorpe（group）Co.,Ltd.）,using traditional manual sampling,manual monitoring methods and built automatic sampling and monitoring system to monitor and analyze the effluent water quality,and eventually through comparative analysis to study the application feasibility of the system.It is shown that the outlet for COD of the four enterprises is between 5-50mg/L,and the relative error of the automatic sampling and monitoring system is less than 20%.To sum up,for COD,the automatic sampling monitoring system can meet the accuracy requirements of sampling analysis.The NH₃-N monitoring at the outlet of Zheng Runzhou Sewage Treatment Plant and Dagang Sewage Treatment Plant is 0.1-1.0mg/L,of which the relative error of the automatic sampling monitoring system is less than 15%;the NH3-N monitoring at the outlet of Jindong Paper（Jiangsu）Co.,Ltd.,Jiangsu Thorpe（Group）Co.,Ltd.is more than1.0mg/L,of which the relative error of the automatic sampling monitoring system is less than 10%.To sum,for NH₃-N,the automatic sampling and monitoring system can meet the accuracy requirements of sampling analysis.The concentration of total phosphorus in the outlets of the four enterprises was between 0.025-0.6 mg/L,and the relative error of the automatic sampling monitoring system was less than 10%.For total phosphorus,the automatic sampling monitoring system can meet the accuracy requirements of sampling analysis.With high analysis accuracy,the relative error of pH monitoring and analysis at the outlet of the four enterprises is less than 1%,which can meet the accuracy requirements of sampling and analysis.For the petroleum at the outlet of the four enterprises,the relative error is relatively large when the automatic sampling and monitoring system is used for monitoring,of which the relative error of the petroleum at the outlet of the sewage treatment facilities of Dagang sewage Treatment Plant and Jindong Paper（Jiangsu）co.,ltd.are both more than 40%.To sum up,the established automatic sampling and monitoring system is not suitable for automatic sampling and monitoring of petroleum.