PREDICTING NONEQUILIBRIUM TRANSPORT OF NAPHTHALENE THROUGH AQUIFER MATERIALS USING BATCH DETERMINED SORPTION PARAMETERS

Batch experiments with naphthalene sorption onto three aquifer materials with low organic carbon contents (less-than-or-equal-to 0.025%) yielded kinetic parameters in accordance with the bicontinuum nonequilibrium model model (K(d), F, k2). About half of the sorption was instantaneous while the complementary sorptive fraction developed over 20 to 200 hours depending on the aquifer material. The equilibrium distribution (K(d)) was linear as assumed by both the equilibrium and the bicontinuum nonequilibrium solute transport model. The batch determined kinetic parameters were successfully employed in predicting the breakthrough curves for the laboratory columns exposed to constant influent concentration of naphthalene. For two of the aquifer materials showing very little retardation of naphthalene (K(d) almost-equal-to 0.15 ml/g) the equilibrium and the bicontinuum nonequilibrium model gave comparable results, while the nonequilibrium model, using batch determined parameters, was superior to the equilibrium model in the case of the aquifer material showing K(d) values of the order of 1 ml/g and a flow velocity of 75 m/y.