挥发性有机污染物去污过程的数值模型及应用

Numerical model of volatile organic compounds remediation and its application

基于多孔介质渗流力学和溶质运移理论,建立了描述挥发性有机污染物在非饱和土壤中运移的耦合动力学模型,并采用有限差分方法对模型进行数值求解.利用所建立的数值模型对土壤气体抽排状态下甲基叔丁基醚有机污染物的去污过程进行定量化模拟,并与实验测试结果进行对比分析.数值模拟结果表明:在连续抽排条件下污染气体的分布范围和浓度均明显减小,抽排前期对气体浓度分布有较大的影响,且数值模拟结果和实验测试数据吻合较好,可为气体抽排系统工程设计及环境预测评价提供技术支持.

Based on the theory of fluid flow in porous media and solute transport, a coupled dynamic mathematical model of migration of volatile organic compounds （VOC） in the unsaturated soil was established. The solution of the coupled equations was accomplished by using the finite difference method. The numerical model was used to predict the temporal and spatial distribution of VOC concentrations under the conditions of soil vapor extraction. The model solutions were compared to experiment values. Results showed that there was an obvious decrease both in the concentration and in the range of presence of volatile organic compounds during the period of soil vapor extraction. Soil vapor extraction had a large impact on VOC concentrations at the early stage, with reasonable agreement between model numerical solution and measured data, which provided a quantitative verification of the model. The theoretical and technical principles were provided for engineering design of soil vapor extraction system and for environmental prediction of vapor migration.