Effect of distance-dependent and time-dependent dispersion on non-linearly sorbed multispecies contaminants in porous media

Abstract

In this study, the effect of distance-dependent and time-dependent dispersion coefficient on the transport of multispecies contaminants subjected to Freundlich non-linear adsorption in porous media has been analyzed. An implicit finite difference has been used to develop the numerical model. A constant continuous source of first species contaminant has been assumed at the inlet of the porous domain. The results obtained from distance-dependent and time-dependent dispersion coefficient has been compared with that obtained using constant dispersion coefficient for different fluid velocities and dispersivity–distance ratios. The first species of the multispecies transport is subjected to Freundlich non-linear sorption. Sensitivity analysis has been conducted to study the effect of different simulation time, fluid velocities, sorption exponent, and dispersivity–distance ratio on solute transport mechanism within the porous media. Results suggest that the effect of distance-dependent dispersion coefficient on multispecies contaminant movement is negligible when the fluid velocity is very low. The fluid velocity has a significant impact on the multispecies solute movement when non-linear sorption and distance-dependent dispersion coefficient are considered. The effect of variation of the Freundlich sorption exponent on contaminant concentration is negligible when distance-dependent and time-dependent dispersion coefficients are considered.