US Geological Survey


Date of this Version



Water Resources Research, Vol. 19 No. 2, Pages 381-391, April 1983


One-dimensional transport of solutes in a saturated porous medium has been simulated using a numerical model CHEMTRN. This model includes dispersion/diffusion, advection, ion exchange, formation of complexes in the aqueous phase, and the dissociation of water. The mass action, transport, and site constraint equations are expressed in a differential/algebraic form and solved simultaneously. In. the mass action equations describing complexation and sorption processes, the activities of the species in the aqueous phase are approximated using the Davies equation.