Modeling Bromide Transport in Undisturbed Soil Columns with the Continuous Time Random Walk

Abstract

Nowadays, mathematical models are commonly used as efficient tools in solute transport studies and management in porous media. In this paper, we evaluated the continuous time random walk (CTRW) theory for its capability to characterize bromide transport in one-dimensional saturated undisturbed clay loam and sandy loam soil columns (10 cm in diameter and 40 cm long). The transport process was also simulated by using the advection–dispersion equation (ADE) for comparison. The values of CTRW parameter, β, for clay loam and sandy loam soil columns were derived at 1.71 and 1.73, respectively. This indicated that the bromide transport behavior within the clay loam and sandy loam soil columns was anomalous transport or non-Fickian transport and CTRW model was more suitable for simulation of bromide transport through undisturbed clay loam and sandy soil columns compared to ADE model with Fickian diffusion law basis. The graphical and statistical analysis confirmed the efficiency of CTRW model for simulation of bromide transport.