Evaluation of Sorption Models in the Simulation of Naphthalene Transport Through Saturated Soils

摘要

The transport of organic pollutants in ground water is determined by the physical, chemical, and biological processes occurring within the porous medium. To show the effect of sorption model selection, the one-dimensional transport of naphthalene in two saturated soils was simulated using numerical models, which included the processes of dispersion, advection and sorption. Three different models describing the sorption process: (1) a local equilibrium model,((2) a first-order kinetic sorption model, and (3) a two-site model were examined. In addition, the study considered two types of boundary conditions: constant concentration and constant flux boundary conditions. Simulations were made for data of naphthalene transport through a laboratory soil column packed with Lincoln or Eustis soil series. Numerical simulation results show that the selection of the sorption model had significant effects on the numerical solutions. The numerical solution obtained using either the local equilibrium model or the first-order kinetic sorption model described the experimental data very well from the Lincoln soil column. In contrast, the numerical solution obtained using the two-site model described the experimental data for the Eustis soil better than the equilibrium or kinetic model. Different boundary conditions had little influence on the numerical solutions.