Uncertainty-based Risk Evaluation Model And System Development For Hazardous Waste Smelting And Recycling

Heavy metal hazardous wastes（HMHWs）are the focus and difficulty of global solid waste management due to the large amount and high hazard.Smelting regeneration has the dual effects of harmlessness and valuable metal recycling,and is the main method for the utilization and disposal of HMHWs.However,in the process of smelting and regeneration,the toxic and harmful components in HMHWs may be released in the form of exhaust gas through material recycling,resulting in secondary pollution.Existing researches mainly focus on the standard-compliant emissions and their environmental effects under normal working conditions in the smelting process and the standard-compliant emissions under accident scenarios.There are few studies on the environmental effects under accident scenarios,especially the uncertainty.However,the high concentration rapid emission（HCRE）of pollutants caused by the accident is due to the large source intensity and the strong chance of atmospheric diffusion conditions in the short term,resulting in serious environmental pollution consequences,great uncertainty,and greater environmental risks.Therefore,it is urgent to reveal the environmental consequences,probability and spatial distribution characteristics of hazardous waste smelting and regenerating HCRE,accurately identify possible hidden risks,and provide scientific information for environmental emergency monitoring and decision-making and buffer distance setting under HCRE conditions of related facilities.refer to.In this regard,the paper studies and proposes a coupled model algorithm for quantitatively evaluating the consequences and uncertainties of air pollution under HCRE conditions.The system is validated and case studies are carried out.The main research contents and conclusions are as follows:（1）The physical process of exhaust gas emission under HCRE conditions was systematically analyzed,and the Gaussian plume model suitable for the simulation of its physical process was screened,and the important factors in the model were corrected for wind speed and complex terrain.（2）Identify the key uncertainty parameters of the model through Sobol sensitivity analysis,carry out the coupling study of the physical model and the uncertainty method for the identified parameters,respectively construct and compare the Monte Carlo and Random Response Surface Method（SRSM）and Gaussian plume（The results show that the mean and standard deviation of 1000 times 3rd-order SRSM and 10,000 times MC simulation results are only 1.27%and 0.72%different,indicating that the third-order SRSM maintains the calculation accuracy and improves the Computational efficiency of uncertainty analysis.（3）On the basis of the GAUSS-SRSM coupling research,the system integrates the risk assessment algorithms of smelting and recycling facilities,storage,landfill and other links,and develops a visual system for environmental risk assessment of hazardous waste smelting and recycling atmosphere,which realizes hazardous waste smelting and recycling atmosphere under HCRE conditions.Effective characterization of environmental risk consequences and their uncertainties.（4）A regenerated lead enterprise in North China was selected to carry out system verification and case study.The results show that:1）Compared with the American atmospheric estimation model AERSCREEN,the two simulated atmospheric pollutant diffusion and migration laws are basically the same,and the maximum values of SO2 and Pb are the same.The relative error of the predicted concentration at the landing point is only 7.08%and 4%,and the simulation accuracy of the system is acceptable.2)The probability of SO2 and Pb exceeding the standard in the target pollutants discharged by enterprises is 44%and 28%,and the exposure concentration（characterized by the 95%quantile）is seriously polluted in the downwind direction of 0.8-2.2km If the degree of pollution is large,the installation of pollution-sensitive facilities in this area should be avoided,and it should be used as a key area for emergency monitoring after the accident.3)Uncertainties such as climate and source intensity make the consequences of air pollution obvious uncertainties.As the distance increases,the uncertainty decreases.The uncertainty in the range of 0.5-1.2km is relatively large,and possible random errors can be overcome by strengthening the monitoring frequency.