Characterization of solute transport parameters in unsaturated porous media: A Technical Paper

Abstract

The study of solute transport processes in the soil requires the estimation of hydrodynamic dispersion coefficient and distribution coefficient. Soil column experiments were carried out on three soils (Sand – Loam – Clay) by injecting a solution of 0.8 M KCl in a steady state. Breakthroughs curves are symmetrical, characteristics of an equilibrium solute transport. The hydrodynamic dispersion coefficients were estimated by optimizing the measured breakthrough curves with the analytical solution of the advection-dispersion equation (EAD) by the software CXTFIT. The validations of the results were performed by a direct simulation with Hydrus-1D model. Statistical analysis showed the success of the used method to estimate the solutes transport parameters of the studied soils. A laboratory experiment based on Batch equilibrium method was developed. This method is based on mixing a soil with water solutions with different concentrations and adjusted the obtained isotherms on analytical models. The method was applied to three soils and the results have demonstrated its validity.