APPLICATION OF A MULTIPROCESS NONEQUILIBRIUM SORPTION MODEL TO SOLUTE TRANSPORT IN A STRATIFIED POROUS-MEDIUM

The purpose of this work was to investigate the capability of a model, which explicitly accounts for multiple sources of nonequilibrium, to predict the transport of nonequilibrium sorption-constrained solute in a stratified porous medium. Microaquifer experiments reported in the literature served as the source of the data that were analyzed. The best available information was used to identify values for all model input parameters, allowing the multiprocess nonequilibrium (MPNE) model to be used in a predictive mode. The prediction produced by the MPNE model provided a good description of the breakthrough curve obtained at a given velocity. A breakthrough curve obtained at a slower velocity could be simulated when the apparent velocity dependence of the physical nonequilibrium parameters was taken into account. Based on the reported results, the MPNE model would seem to provide a valid representation of sorption dynamics and solute transport for stratified systems influenced by sorption capacity heterogeneity and multiple sources of nonequilibrium. The relative and combined impact of interlayer mass transfer, chemical nonequilibrium, and sorption capacity heterogeneity on the transport of a sorbing solute was elucidated.