The main objectives of this study is to model the transport of methylene blue (MB) in homogenous and layered soils which has been studied experimentally by fixed bed column. The effect of soil stratification has been studied through numerical investigation based on the coupled solute transport model in three-layered soil. The effect of some significant parameters such as flow rate, initial concentration of MB, thickness of each layer and the numbers of layers on the breakthrough curves have been undertaken. A finite element analysis model was employed to predict the transport of MB in soils. A two dimensional model based on Richards equation and advection-dispersion equation coupled with adsorption model has been developed and an analytical model has been used to predict the dispersivity. The results shows that the soil heterogeneity has a significant effect on methylene blue (MB) adsorption through unsaturated layered media and the effect of the parameters of the upper layer of the soil is more significant than those of the lower layer but this effect can be controlled with the choice of the thicknesses of each layer.
In this work, we investigated the morphological effect of dichloromethane (DCM) on alfalfa (Medicago sativa) plant. We studied in vitro the influence of its concentration on alfalfa germination. The plants were placed in pots for 15 weeks, and exposed to increasing concentrations of DCM (50 mg L À1 and 84 mg L À1 ). In addition, we examined the effect of two manures (cow and sheep), which were applied to a contaminated soil, on alfalfa plant growth. The effect of the presence of dichloromethane is obvious even in plant-soil manure system. In fact, in the event of contamination, the soil-cow manure mixture represents the best setting medium for the Alfalfa plant compared to other environments, regardless of the contamination level. Indeed, the presence of two types of manure does not allow the suppression of the inhibitory effect of dichloromethane on the mass of the dry matter of the aerial part which is 18.38% for the cow manure-amended soil and 13.96% for the sheep manure-amended soil.
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