Comprehensive Evaluation System Of Environmental Risk Sources And Management Measures In Urban Water Source

In recent water sources protection, a river water quality declined increased and the pollution events are frequently happen, besides, the city for the dependence of water gradually increased. The reason is the rapid development of new industrialization, agricultural modernization, urbanization. The security of urban water resources has become an important factor restricting the development of the city. Risk assessment and protection of urban water sources have become the focus of the department of environmental protection. The main risk of city water sources are flow risk source, non-point risk source, stationary source. For instance, Oil Spilling or leakage of hazardous chemicals from ship、fertilizer pollution、pollution of livestock and poultry breeding、 hazardous chemical plant explosion, and so on. These pollution incidents seriously affect the safety of city drinking water sources. These three kinds of pollution sources have many characteristics, such as occurrence time randomness、complexity of contaminant transformation mechanism、emergency management lag, serious result, wide range of pollution, incalculable losses, and so on. How to deal with the sudden water pollution incident in city water sources has become a realistic problem. Establishing comprehensive risk assessment system from the perspective of protection of drinking water sources, and determine the main risk sources and risk factors by weight analysis, further more provide support for water resources protection and management.In this paper, firstly, discussing the background、significance of the selected topic、 research progress and existing problems; secondly, through field monitoring and research to determine the research objectives and content; finally, by analyzing the data and calculation to find out the main influence factors and put forward the comprehensive evaluation index system of urban water resources.In this paper, the flow risk source monitoring step is divided into six steps, preliminary design, scheme optimization, monitoring preparation, monitoring implementation, data collation and analysis, risk evaluation respectively. Classification based on construction projects environmental risk assessment method and environmental monitoring experiment design method. During the monitoring process, the main records is ship passing time, ship models, navigation direction, cargo types, ship hull number, weather conditions and other information. Since the preliminary design of the record form, through consultation with relevant experts and pre experiment to further optimize the experimental program. The materials and equipment needed to be prepared before the monitoring, including counting tools, photography tools, thermal tools, etc. Careful observation and recording of the monitoring process, as far as possible to reduce the test error caused by personnel problems. Using analytic hierarchy process to analyze the weight of the main risk factors and identify the key risk factors.Research on non-point source and stationary source, calculate production and emission of pollutants from planting, resident life, livestock, poultry, aquaculture and stationary source. The risk assessment factors were determined according to the amount of COD, NH3-N and other pollution generated from each pollution source. The weight of each index is calculated by the analytic hierarchy process, and the main risk factors are determined.In this paper, the research area is Taipu river in shanghai, adopting the method of artificial observation to record the detailed information of transit ship. During monitoring period (72 hours),1857 ships pass by Taipu river bridge totally, including 994 bulk cargo ships,742 empty ships,121 dangerous cargo ships. Types of goods in bulk to sand, gravel, a cloth to cover goods and other items mainly, dangerous cargo to canned liquid and solid chemicals mainly. If hazardous pollutants enter the river will be a serious threat to water quality and affecting the safety of nearby residents. Through combing the general situation and management status of flow risk source, analyzing and evaluating the risk of the transit ship pass by drinking water source area of Qingpu district, it provide data support for the management of urban water supply source.In this paper, the west of Qingpu district (Zhujiajue Town, Liantang Town, JinZe Town) as the research scope of non-point source and fixed source. The pollutants produced annually by the non-point risk sources:COD is 4248.94 tons, NH3-N is 252.59 tons, TN is 1228.70 tons, TP is 422.33 tons. The pollutants produced annually by stationary risk source:COD is 270.30 tons, NH3-N is 17.50 tons, TN is 65.10 tons, TP is 3.50 tons. Less dangerous goods factory in study area, the probability of sudden leakage of dangerous goods becomes small. Livestock and poultry breeding, residents live produce the greatest amount of pollution, therefore need to strengthen supervision of livestock and poultry farms, increase the rural domestic sewage treatment facilities, strengthen the centralized sewage treatment.In this paper, the characteristics of urban water resources are complex, social, comprehensive, systematic, and so on. Through field monitoring, field research, data collection and other methods try to build a comprehensive risk assessment index system of water source. It based on the analysis of the present situation of environmental risk sources, quickly find out the environmental risk factors of water source and determine the importance of each index to the evaluation system through the analytic hierarchy process. Provide reference for the protection and management of urban water resources. The index system selected 25 evaluation indexes from three risk sources (flow risk source, non-point risk source, stationary source), and set up a set of comprehensive evaluation index system.According to the field monitoring and statistical data analysis, combined with the index weight calculation, we found that life risk sources and livestock were the main source of risk. The main influence factors include:types of transport goods, the planting area, regional population density, number of aquaculture and fixed source pollution. It’s necessary to put forward the management measures based on the key influence factors and main risk sources, to provide services for the protection of sensitive receptors.