污染物运移过程的一维数值分析

考虑填埋场中固体废弃物的生物降解效应和含水层中土颗料对污染物的吸附性,在有限深度条件下基于对流、弥散和地球化学反应等污染物运移机理,提出了填埋场污染物运移过程数值模拟的一维计算模型。进而采用半解析方法进行数值求解,通过变动参数比较分析确定了控制填埋场污染物运移过程的主要参数。具体数值计算表明:污染物在含水层中运移浓度将于某一特定时间达到峰值,随后逐渐降低。粘土垫的厚度及其渗透性、压缩粘土垫层与含水层的吸附能力是填埋场污染物运移的重要近控制参数。

One-dimensional numerical analyses of migration processes of pollutants through a clay liner considering sorption of aquifer

Presented in this paper is a one-dimensional computational model for numerical simulation of migration process of pollutants in waste landfills which can take both the sorption of aquifer and bio-degradation of wastes into consideration. The model, for the case of a clay liner of finite depth, can simulate the complex migration mechanisms including advection and dispersion transport as well as geochemical reaction. Based on the computational model, numerical solutions are achieved by using semi-analytical procedure. Then through comparative parametric studies, the key factors which considerably control the migration process of containments are defined based on the numerical results. It is shown that for most practical situations the concentration of contaminant within the groundwater beneath landfill will gain its peak value at a specific time and subsequently will decrease with time. It is found that the most important factors affecting the migration process of pollutants include the thickness and permeability of the clay liner, sorption capacities of both aquifer and clay liner.