Environmental Risk Assessment And Prevention During The Decommissioning Process Of Small And Medium Sized Electroplating Plants Based On Bayesian Network

The relocations number of of small and medium-sized electroplating plants has increased significantly affected by changes in the urban structure and the transformation of industrial upgrading,which lead to gradual exposure of environmental risks.In order to avoid adverse effects on the environment during the decommissioning and relocation of small and medium-sized electroplating factories,an environmental risk analysis method combining Bayesian network and Bow-Tie model was proposed.this paper.Firstly,make an in-depth analysis of the environmental risk system for the relocation of small and medium electroplating factorie,and identify environmental risks by Bow-Tie model.Secondly,constructing the Bayesian network by mapping operation,and calculating the prior probability based on the information diffusion theory.Put prior probabilities into GeNIe software,and screening for environmental risk factors and accident evolution paths.The pollutant migration mathematical model was used to simulate the trajectory of pollutant leakage in various environmental media,and the hazard degree of the leakage accident to the plant area and its surrounding areas was grasped in real time.With the aid of semi-quantitative risk matrix,and combined with probabilistic risk assessment results and real-time consequences evaluation results,The multi-media environmental risk assessment grading is conducted.Finally,scientific and effective environmental risk prevention and emergency measures are proposed.The full text of innovative results are as follows:?1?Identifying environmental risks by Bow-Tie model.The results show that environmental risks during the decommissioning of small and medium-sized electroplating plants mainly include chemical leakage,loss of hazardous wastes,secondary environmental fire accidents,excessive discharge of waste water,and exhaust gas unorganized.Among them,the leakage is a key event in the environmental risk system,and soil pollution is the main consequence of its evolution.?2?The projection based on the Bayesian network analysis model shows that the probability of leakage during the relocation of the small and medium electroplating factory is 1.02×10^-4,which is in the same order of magnitude as the 1.1×10^-4 announced by DNV.Apply the model to the decommissioning and relocation process of Hefei Mingguang Electroplating Factory,the results showed that the probability of soil contamination during the relocation of Hefei Mingguang Electroplating Factory was6.83×10^-4.The path of soil pollution caused by the leakage accident degeneration is as follows:Corrosion damage of container or the failure disposal of flushing wastewater,leading to leakage of pollutants,in the containment and seepage and other security barriers in the conditions of failure into the soil,causing soil contamination.The focus of environmental risk prevention is to check tanks,collect and test flushing wastewater before starting relocation,and temporarily store the hazardous materials on the seepage-proof ground in order to enhance the role of seepage barriers.Under the above measures,the probability of leakage accidents dropped to 2.0/10^-5F,and the probability of soil pollution fell to 4.0/10^-8F.?3?Apply the mathematical model of pollutant migration to the simulation prediction of leakage accident during the relocation of Hefei Mingguang Electroplating Factory,results show that Zn²⁺migrated vertically to underground 1.8 meters within 20days and migrated horizontally to 2.5 kilometers reservoir area,as an external source causing water pollution.Environmental risks reached Level II or higher at all stages of the simulation.And environmental risks are reduced to Level I in the joint action of environmental risk prevention measures and emergency prevention measures of recovery,dilution,digestion and other.?4?In summary,the environmental risk prevention and emergency measures proposed in this paper are scientific and effective.The environmental risk analysis model based on Bayesian network can solve the environmental problems during the relocation of small and medium-sized electroplating factories,and it can provide a general model method for the evaluation and prevention of environmental risks for the decommissioning of similar industrial enterprises.