污染物传输的两区非平衡吸附数值仿真模型

考虑不可动水和污染物的非平衡吸附特性以及微生物降解等因素,建立了土壤-水环境中污染物运移的两区非平衡吸附模型。基于自行编制的有限差分程序给出了二维仿真算例,模拟了农药等污染物在土壤-水环境中的运移过程,探讨了在不可动水和非平衡吸附影响下土壤中各相浓度分配的规律。模拟结果表明:土壤各相的浓度变化并不同步。可动水相浓度变化最快,对浓度分布起主导作用;不可动水次之;可动区吸附相浓度变化存在明显的滞后现象;而不可动区吸附相浓度变化最为缓慢,滞后现象最为明显。

Numerical Simulating Model of Contaminant Transportation Considering Immobile Water and Non-equilibrium Adsorption/Desorption

The kinetic model of contaminant transportation in the soil-water system was established considering the immobile water,non-equilibrium adsorption/desorption and microbiological degradation.The model was solved using the corresponding finite difference program.And it was used to simulate a vertical section of soil,which was polluted by pesticide,and the concentration distribution in every phase under the effect of immobile water and non-equilibrium adsorption/desorption was discussed.The result demonstrates that the changes of concentration in every phase of soil are not synchronous.The change of concentration in mobile water phase is the fastest,it has the leading effect on concentration distribution;the change of concentration in immobile water phase takes the second place,the phenomenon of concentration hysteresis in non-equilibrium phase corresponding with mobile water is obvious;and the change of concentration in non-equilibrium adsorption phase corresponding with immobile water is the slowest,the phenomenon of hysteresis in it is the most obvious.