Estimation of zeolite application effect on solute transport parameters at different soils using HYDRUS-1D model

ABSTRACT-Application of models for simulation of solute and pollutants transport in soil can reduce time and costs for remediation process. HYDRUS-1D model was developed to simulate the one–dimensional flow of soil water, heat, solute and viruses in variably saturated–unsaturated porous media. The objective of this investigation is to determine the solute transport parameters in disturbed soil columns with different textures at different rates of zeolite application using HYDRUS-1D model. For this study, the loam soil, the sandy loam soil and the clay loam soil with zeolite application rates of 0 (control) and 8 g kg-1 were used. The approximate concentration of effluents measured by other investigators (0-2.26 mg cm-3) is used to determine the transport parameters. The value of immobile water content (θim) decreased and the value of hydrodynamic dispersion coefficient increased in lighter soil texture. According to hydraulic parameters considered and regression equation proposed by other researchers, the decreasing trend of θim is valid with  increasing saturated hydraulic conductivity. The predicted dispersivity (λ) in control treatment was in the range of value of λ for disturbed soil reported by other researchers. The trend of solute transport parameters calculated by breakthrough curve using the analytical method by other researchers is similar to the estimated values by the HYDRUS-1D model. The values of Willmott’s agreement index are more than 90% for all soil treatments and normalized root mean square error is about 20% for most treatments that indicated the good accuracy of model for predicting solute transport coefficients.