| With the change of China’s economic development model from high-speed growth to medium-speed growth,ecological environmental protection has become a priority in the country’s development,and the effectiveness of environmental protection has begun to emerge,and the overall level of environmental management has improved.However,due to the complexity of the social environment,sudden water environmental incidents still occur from time to time.The uncertainty,coupling,and severity of the damage caused by water emergencies have made them a painful and difficult point for economic and social development.How to avoid the occurrence of water environmental emergencies and improve the effectiveness of environmental risk management has become a key unit of China’s 14th FiveYear Plan and the construction of ecological civilization.The risk assessment of water environmental emergencies is important for urban governors to grasp the environmental risk situation,clarify the focus of risk prevention and control,and deepen risk management at source.This study takes the risk of sudden water environmental events as the assessment object.Firstly,by collecting the major sudden water environmental events that have occurred in the past ten years,judging their development and accident causative factors,on the basis of clarifying the relevant interest subjects and the mechanism of environmental risk,the fault tree analysis method is used to identify and screen the risk factors of sudden water environmental events,and they are summarized into four dimensions:risk source hazard,risk receptor sensitivity,risk monitoring power and risk response power.Secondly,considering that disaster factors of sudden water environmental events are many and most of them are uncertain factors,and Bayesian network analysis can analyze safety risk events with incomplete data and insufficient information,this study transforms the fault tree of sudden water environmental events into a Bayesian network topology according to the mapping relationship between fault tree analysis and Bayesian network analysis.Through structure learning,parameter learning and inference analysis,a Bayesian network model for risk assessment of sudden water environmental events is systematically constructed.Finally,the assessment model is applied to the specific case of X wastewater treatment plant,and through the diagnostic reasoning,optimal causal chain analysis and sensitivity analysis of the Bayesian network,it is concluded that:X wastewater treatment plant has risk symptoms such as prominent hazardous impact of risk sources,public participation is still weak,risk monitoring and early warning needs to be strengthened and emergency management system needs to be improved,which verifies the applicability of the assessment model.In response to the risk assessment results,this study fully considers the functions of the three major interests of enterprises,the public and the government in the prevention and control of the risk of sudden water environmental events,and proposes specific prevention and resolution strategies in terms of promoting the regular management of risk sources by enterprises,enhancing social participation in environmental governance and playing a leading role in government risk governance,with a view to providing reference for promoting the source management of sudden water environmental events and building a common governance pattern of environmental protection by multiple subjects. |
