Studying On The Leakage Risk Of Contaminated Groundwater Of A Chromium Salt Based On Sequential Monte Carlo Method

In recent years, with the rapid development of economy, the quality ofenvironment was became worse and worse, and the pollution event of waterenvironmental was also become more frequent, especially the sudden river pollutionaccident. In view of the uncertainty, emergency, diversity, the serious consequences ofform, and the consequences are very serious and treatment is very difficult. Thesudden river pollution has always been the focus and difficulty of river water qualitymanagement. Therefore, to prevent the accidents of sudden pollution of waterenvironment the risk analysis and assessment of water environment should be carriedout actively was particularly important.Firstly, in this article, through engineering software MATLAB to establishinstantaneous pollution accident risk prediction model, consequently to realizereal-time state simulation of pollutants in the process of contaminant migration. andalso discusses the exceeds bid section length and the highest concentration of areachange with leakage when long situation based on the engineering software MATLABto establish instantaneous pollution accident risk prediction model, so as to realizereal-time state simulation of pollutants in the process of migration, and also discussesthe exceeds bid section length and the highest concentration of leakage with longchangesTherefore, combined Sequential Monte Carlo with the surface water qualitymodel，the model of water environment risk was established for the potential sourcesof pollution, with which the probability of simulated river water quality exceeding thecorresponding water quality standard was calculated in the simulation time. there aremany uncertainties (accident probabilities, leakage time) in the pollutant source，which lead to the results of risk inaccuracy. Probability distribution function isapplied to analyze the failure rate model of pollution source system and estimate theinitial release failure rate. On the other hand, long-standing risk sources are suddenand uncertain; This paper attempts to use sequential Monte Carlo method to simulaterisk probability and examines the impact of input variables on results. Aiming atsurrounding special cases, this paper chooses one of China’s typical contaminatedsites, chromium salt field, to carry out research by coupling sequential Monte Carlomode with river water quality mode to compute excessive risk probability. This coupling mode mainly comprehensively considers the status of risk sources, i ncludingthe impact of variables such as accidental state probability, average leak duration andsource intensity on risk assessment; with the underground water of the chromium saltfield as an example, this paper also simulates the process of sequential d ynamicchange of the pollution sources through sequential Monte Carlo mode (SMC), andwith reference to corresponding river water quality model, studies the risk probabilityof standard-exceeding of water quality resulted; human health risk caused bycontaminant leak is also assessed using health risk assessment mode, and the damagedegree is also computed. The result shows that the stability of sequential Monte Carlomode-water quality coupling mode increase with time, with variance below8E-5andstandard deviation below3E-3in more than once simulation experiments; simulationresult is positively related with accidental state probability and average leak duration.When accidental state probability rises from0.0002to0.005, excessive riskprobability increases from0.006to0.1652. When average leak duration rises from12h to72h, excessive risk probability increases from0.0181to0.0873. the hazarddegree of human health caused by polluted surface water was moderate. Theunderground water of the field poses certain threat to nearby rivers and downstreamtarget sections.Moreover, the merit and demerit was compared between the two risk calculationmethods. The results showed that the first method calculated fracture risk based onsingle water quality model, and the other method, however, considered the influenceof the state and scheduling of risk source. Furthermore, this method calculated thetotal risk of repeated leakage in the whole operation period.Last, some countermeasures and suggestions were proposed for the precautionand dispose of such the accident water pollution.