Groundwater Contaminant Transport: Advection-Dispersion Kinetics, Sorption Isotherms, and In-Situ Remediation
Groundwater contaminant transport modeling predicts the subsurface migration and transformation of chemical pollutants dissolved in porous aquifers. Contaminants introduced via industrial spills, unlined landfill leachate, or agricultural runoff move through saturated zones under the combined physical mechanisms of advection, mechanical dispersion, and molecular diffusion, modified by geochemical attenuation reactions. The one-dimensional transient transport of a reactive dissolved solute through a homogeneous, isotropic porous medium is governed by the Advection-Dispersion Reaction Equation (ADRE) : $$R \cdot \frac{\partial C}{\partial t} = D_x \cdot \frac{\partial^2 C}{\partial x^2} - v_x \cdot \frac{\partial C}{\partial x} - \lambda \cdot C$$ Where $C$ is solute concentration, $v_x$ is average linear groundwater seepage velocity ($v_x = \frac{K \cdot i}{n_e}$, where $K$ is hydraulic conductivity, $i$ is hydraulic gradient, and $n_e$ is effective porosity), $D_x$ is hydrodynam...