Numerical analysis of spatial moment for colloid-facilitated contaminant transport through porous media

Abstract

ABSTRACT Transport of contaminants in the presence of colloids is a three-phase problem in the groundwater porous media and colloids can also enhance the transport of contaminants by reducing the retardation factor. In this study, the numerical solution of the equilibrium model is obtained using a fully implicit Crank-Nicolson finite-difference method and validated with ten experimental results. Sensitivity and spatial moment analysis have been performed to investigate the mobility and spreading behavior of contaminants in the presence of colloids. Results suggest that enhancement of contaminant transport in the presence of colloids depends on the colloid concentration and the physical and chemical interaction of contaminants with the stationary solid matrix and suspended colloids. As the colloidal concentration increases, the mobility of contaminants augments, resulting in the early arrival of contaminants at the column outlet. The affinity of contaminants toward the stationary solid matrix of porous media can lead to the reduced transport of contaminants even under the presence of a significant amount of colloid concentration. In contrast, enhanced transport of contaminants is observed if the affinity of contaminants is more toward the suspended colloids.