This paper presents the behavior of solute transport through mobile-immobile (MIM) soil column based on the laboratory study. The study considers that the advective-dispersive transport equation is used for mobile domain, and the solute exchange between two liquid domains is described as the firstorder process. A numerical model is developed for the MIM advective-dispersive transport equation including equilibrium sorption and the first-order degradation. Afterward, the numerical model is used to simulate experimental breakthrough curves (BTCs) for transport of chloride and fluoride through heterogeneous soil column using constant, linear, and exponential distance-dependent dispersion models. It is shown that the behavior of concentration profile produced with a constant dispersion model is similar to the distance-dependent dispersion model. It is found that the constant dispersion and the exponential distance-dependent dispersion models simulate experimental BTCs reasonably well as compared to the linear distance-dependent dispersion model. Hence, the exponential distancedependent dispersion model is a simple and practical approach to describe the solute transport through the MIM porous media.

No abstract