A METHOD TO SOLVE THE ADVECTION-DISPERSION EQUATION WITH A KINETIC ADSORPTION-ISOTHERM

This study deals with a method to solve the transport equations for a kinetically adsorbing solute in a porous medium with spatially varying velocity field and dispersion coefficients. Making use of the stochas tic nature of a first-order kinetic process, we show that the advectio n-dispersion equation and the adsorption isotherm can be decoupled. On ce the solution for a non-adsorbing solute is known, the method provid es an exact solution for the kinetically adsorbing solute. The method is worked out in four examples. In particular we demonstrate how the m ethod can be applied simultaneously with a numerical transport code: t he advective-dispersive transport is computed numerically, whereas kin etic effects are incorporated analytically. The proposed approach may be useful in field scale applications with complex flow patterns. Copy right (C) 1996 Elsevier Science Limited