Modeling Of Transformation And Migration Of Chlorinated Hydrocarbon In Groundwater

Water is always considered as the source of the life, and groundwater is one of the most significant fresh water resources on our planet. More than half of the world’s population use groundwater as source of drinking water. With the rapid development of industry and agriculture, however, increasingly sources of groundwater have been contaminated. Among these, organic pollution in groundwater is the most ubiquitous case and most difficult to control and remediate. Chlorinated hydrocarbon such as PCE, TCE, and chloroform were frequently detected in groundwater, which attracts the attention of governments around the world. The purpose of this study is to make people learn more about the migration and transformation of chlorinated hydrocarbon in groundwater and provide theoretical support for the treatment of organic pollutants.This article described the process of setting up a numerical simulation on migration and transformation of chlorinated hydrocarbon in groundwater by means of GMS software. Firstly, we established a groundwater flow model, before the solute model being established; the range of the flow model was based on typical contaminated area of chlorinated hydrocarbons. Secondly, we summarized the simulation area and built a conceptual model according to the hydrogeological data. Thirdly, the conceptual model was transformed into numerical model through GMS software and the parameters of the model were identified and validated, in order to make the flow model reflect the actual hydraulic characteristics of the groundwater. Finally, the transformation and migration model of chlorinated hydrocarbon in the study area was set up based on the flow model, and the migration of chlorinated hydrocarbons could be predicted according to our result.According to the result of flow model in the year of 2000, the study area was in a negative balance with the main reason of confronting a dry year whose rainfall was only 364 mm. In addition, excessive exploitation was considered as the other reason of the decline of groundwater level. For solute model, PCE and TCE were considered as the object of research. The simulation demonstrated that: PCE degraded continuously into TCE in groundwater, and the center of TCE plume at downstream continued to drift downward. The degradation of PCE and TCE were mainly related to red-ox environment. In the model, retardation coefficient of PCE and TCE in groundwater showed little difference, with the value of 6.52 and 6.34, respectively. In contrast, the degradation coefficient showed a significant difference; the value of PCE was 0.0006 while that of TCE was 0.0001. In sum, the range of TCE plume and PCE plume expanded to different extents and the concentration of these two pollutants continued to reduction. The concentration of several individual points in the model may be increased, with a small increasing rate.The sensitivity analysis of parameters in solute model was also discussed, whose result showed that the range of TCE plume was most sensitive to conductivity coefficient, whereas the total mass of TCE was most sensitive to TCE anaerobic constant and least sensitive to conductivity coefficient.