SOLUTE TRANSPORT IN AGGREGATED POROUS-MEDIA - COMPARING MODEL-INDEPENDENT AND DEPENDENT PARAMETER-ESTIMATION

In many studies on solute transport soil column experiments are used t o obtain the transport characteristics for Convection-Dispersion-Model s. Early breakthrough of the solute pulse has been attributed Lo a non -equilibrium in phase exchange. It is a standard procedure Lo determin e several model parameter values from such breakthrough curves (BTC). This investigation is focused on the physical significance of simultan eously fitted parameter values used in the convection and diffusion-co ntrolled mass transfer model (mobile - immobile phase concept). Satura ted column experiments were conducted with solid phases consisting of porous and solid glass beads. One set of model parameter values was ob tained from the breakthrough curves by simultaneous optimization and a second set was determined by independent measurements of individual p arameter values. Both sets of parameter values described the BTCs equa lly well but deviated substantially froin each other. These discrepanc ies were analysed in terms of local parameter sensitivities.