POLLUTION TRANSPORT IN THE THREE-LAYER SYSTEM CONSIDERING NONLINEAR SORPTION OF UNSATURATED SOIL.

According to the actual situation oflandfill site, it is assuming a three-layered system of compacted clay liner, unsaturated aquifer underlain the landfill, and one-dimensional governing equations for leachate transport in each layer of three-layered system are established. The governing equation are solved by numerical methods, which taken into account the effects of equilibrium nonlinear sorption of compacted clay liner and nonlinear sorption of unsaturated soil. The numerical simulation are carried out by varied the parameters, and the results show that the nonlinear sorption of unsaturated soil is more sensitive to pollutant transport than nonlinear sorption in compacted clay liner, and it became the controlling factor of pollutant transport in unsaturated soil. The nonlinear sorption parameter b_u effects on the pollutant transport are more obviously than the nonlinear sorption parameter S_ml· In the meantime, degree of saturation of unsaturated soil is the controlling factor of pollutant transport. [ABSTRACT FROM AUTHOR]