在处置固体废弃物时多采用具有隔离和屏障作用的压实黏土衬垫体系,其渗透性极低,渗滤液溶质在其中的主要运移方式为扩散。针对各类堆场渗滤液中多组分污染物并存的实际工程现象,研究了多组分污染物在防渗黏土垫层中的扩散规律。基于混合物组分线性动量平衡,引入可考虑组分有效浓度的活度系数,建立了多组分污染物在黏土垫层中的一维扩散模型。使用有限元软件COMSOL Multiphysics对所建扩散模型进行求解,揭示了多组分污染物在黏土垫层中的扩散规律。结果表明:与单组分污染物扩散相比,多组分污染物共存时组分活度的引入对独立组分的扩散起到了阻滞作用。研究结果能够为各类堆场设计合理经济的防渗隔污屏障提供理论依据。
Abstract
Compacted clay liner system with isolation and barrier function used in solid waste disposal is of low permeability. Diffusion, as a consequence, is the dominant pattern of leachate solute migration in the clay liner. In engineering practice, multicomponent contaminants coexist in the leachate of storage yards. In view of this, the diffusion law of multicomponent solute in the impervious clay liner is researched. An equation of multicomponent contaminants diffusion in clay liner is built by introducing the coefficient of activity which reflects the effective concentration of components based on the principle of linear momentum balance. Numerical solution is calculated by finite element software COMSOL Multiphysics. Results show that the introduction of coefficient of activity has hindered the transport progress of individual component. The results could be regarded as theoretical basis when designing economic and reasonable impervious barrier for storage yards.
关键词
多组分 /
污染物扩散 /
活度系数 /
黏土衬垫 /
组分浓度
Key words
multicomponent /
diffusion of contaminants /
coefficient of activity /
clay lining /
concentration of components
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