Abstarct: Waste water containing direct dyes discharged from various industries in particular, textile industry often causes many environmental problems. Studying the possibility of removal of such dyes from wastewater is too much important. In the present study, the advective transport of dissolved contaminants through saturated soil with non-linear sorption of the contaminant on a steady porous media is considered. The non-linear isotherms involved in the transport analysis are the Langmuir and Freundlich isotherms. The presented mathematical model is solved by PHONICS software which is a computational fluid dynamics (CFD) program. Ultimately, the results attained from modeling were compared with the results of laboratory-scale work of AB25, DR81 and DR80 dyes removal from aqueous solutions. The model takes into account the adsorption process incorporating the Langmuir isotherm and second-order kinetic model. The predicted outputs of the model are in close agreement with the experimental data. A sensitivity analysis was also performed to investigate the effects of changing model parameters including: amount of dye adsorbed at equilibrium (q), pseudo-second order kinetics (k2) and Langmuir constant (kl) on dye removal process. It was found out that for DR80 and AB25, the model is most sensitive to the Langmuir constant (kl) and to amount of dye adsorbed at equilibrium (q), respectively. Quantifying the effect of variations in model parameters is important in developing an appropriate treatment system and controlling pollution load discharging to the environment. Although the generation of such wastewater by different industries is quit unavoidable, but the model results presented here can be of help in design of favorable environmental management strategy to minimize the contrary impacts caused by industry wastewater