Study On Numerical Simulation Of Migration And Transformation Of Chlorinated Hydrocarbon In Shallow Groundwater

As a global issue, organic contamination in groundwater is one of the most serious environmental problems the human beings are facing at present. Once organic contaminants enter groundwater, it is very difficult to remove them away. Description in quantity with time-space characters of migration and transformation rules of organic contaminants in groundwater will support theory base for treatment and control of organic contamination. So, it is important and has theoretical and practical significance to study numeric simulation for migration and transformation of organic contaminants in groundwater.Investigation on organic contaminants of shallow groundwater in work area shows that there are two obvious contaminated areas with trichloroethene(TCE) and tetrachloroethene(PCE). But some problems have not been confirmed, for examples: where is contaminated source, how much is contaminated scope, what are influencing factors of contaminant's transformation in study area, and so on. On the basis of this background, and according to the investigation information of organic contaminants, the purpose of this paper is to simulate the migration and transformation of organic contaminants so as to inversely get the location of contamination source by the supposed contamination source and to afford the theoretical supports for the further investigation of organic contaminants in study area. The main contents are as follows:1. The character of distribution, potential chlorinated hydrocarbon contamination sources and the influential factors of migration were analyzed.2. The experiment of migration for TCE and PCE indicates that TCE and PCE is lag obviously, and PCE has the potential to be biodegraded.3. According to hydrogeological and hydrochemical characters, aerobio and anaerobic metabolism exist in the study aquifer.4. The partial differential equations for TCE, PCE, O2, NO3 and microbial were built, and the equations include competition inhibition and nocompetition inhibition.5. Numerical simulation shows that the rate of biodegradation is very low. The anaerobic reductive process is faster with the more highly chlorinate compounds, while the aerobic process is faster with the less chlorinate compounds.The consistence between calculated values of numerical simulation and observed values shows that the biodegradation model and its parameters are accurate in the paper, and the location of the simulated contamination source by modeling is credible.