Numerical study on kinetic/equilibrium behaviour of dissolution of toluene under variable subsurface conditions
21 Jul 2014-European Journal of Environmental and Civil Engineering (Taylor & Francis)-Vol. 18, Iss: 9, pp 1070-1093
TL;DR: In this article, numerically simulating dissolution and transport of toluene under the effect of sorption and biodegradation to understand their synergistic influence during the tailing phase, the authors found that influence of soil grain size and porosity are most significant in calculating the extent of mass transfer limitation.
Abstract: Estimating the extent of kinetic/equilibrium behaviour of dissolution is essential for selecting remediation strategy for highly soluble aromatic constituents of petroleum present in the subsurface. Present study aims at numerically simulating dissolution and transport of toluene under the effect of sorption and biodegradation to understand their synergistic influence during the tailing phase. Subsurface conditions influencing mass transfer such as porous media properties, flow velocity and volumetric residual saturation of toluene entrapped in the pore space are varied and their impacts are assessed. The numerical results in terms of dimensionless numbers suggest that influence of soil grain size and porosity are most significant in calculating the extent of mass transfer limitation. Increases in the volumetric residual saturation results in prolonged near-equilibrium condition for dissolution especially for fine-grained porous media. Tailing is found to be prolonged for sand with low saturations and hig...
Citations
More filters
TL;DR: In this article, the fate and transport of toluene, a light nonaqueous-phase liquids (LNAPLs) in the subsurface region under dynamic groundwater table conditions were investigated.
Abstract: The focus of this study was to investigate the fate and transport of toluene, a light nonaqueous-phase liquids (LNAPLs) in the subsurface region under dynamic groundwater table conditions. ...
39 citations
Cites background from "Numerical study on kinetic/equilibr..."
...Dynamic 77 nature of groundwater table causes significant spreading of pooled LNAPL in smear zone, 78 which considerably increases the LNAPL-water interphase area and resulted in accelerated 79 dissolution (Mobile et al. 2012; Vasudevan et al. 2014)....
[...]
...This in turn significantly 332 increases dissolved phase concentration load to receiving groundwater and vapor 333 contamination to unsaturated pore air (Dobson et al. 2007; Vasudevan et al. 2014)....
[...]
TL;DR: Results compared to previous numerical studies suggest the presence of small scale dissolution fingering created perpendicular to the horizontal dissolution front, mainly triggered by heterogeneities in the medium structure and the local NAPL residual saturation.
26 citations
Cites background from "Numerical study on kinetic/equilibr..."
...Petroleum hydrocarbon dissolution is often described in terms of mass transfer at the NAPL/water interface assuming local equilibrium (Seagren et al., 1999; Sulaymon and Gzar, 2011) or rate limited mass transfer (Miller et al., 1990; Imhoff et al., 1994; Vasudevan et al., 2014)....
[...]
TL;DR: In this paper, the authors proposed that India's soil-water systems provide a vital source of freshwater and sustain the drinking water supply for the world's second-largest population, however, groundwater within the large geogra...
Abstract: India’s soil-water systems provide a vital source of freshwater and sustain the drinking water supply for the world’s second-largest population. However, groundwater within the large geogra...
24 citations
TL;DR: Variations in groundwater flow regimes due to direct draining/pumping and surrounding climatic variabilities may significantly affect the spatial and temporal distribution of hydrocarbon co-... as mentioned in this paper.
Abstract: Variations in groundwater flow regimes due to direct draining/pumping and surrounding climatic variabilities may significantly affect the spatial and temporal distribution of hydrocarbon co...
24 citations
TL;DR: In this article, the authors synthesize and discuss the possible effects of the increase in temperature and groundwater level fluctuations on the behavior of light nonaqueous phase liquid and its components in a climate change context.
15 citations
References
More filters
TL;DR: In this paper, a one-dimensional advective-dispersive contaminant transport model with scale-dependent dispersion coefficient in the presence of a nonlinea r chemical reaction of arbitrary order is considered.
Abstract: A one-dimensional advective-dispersive contaminant transport model with scale-dependent dispersion coefficient in the presence of a nonlinea r chemical reaction of arbitrary order is considered. Two types of variations of the dispersion coefficient with the downstream distance are considered. The first type assumes that the d ispersivity increases as a polynomial function with distance while the other assumes an exponentially- increasing function. Since the general problem is nonlinear and possesses no analytical solutions, a numerical solution based on an efficient implicit iterative tri-dia gonal finite- difference method is obtained. Comparisons with previously published analytical and numerical solutions for special cases of the main transport equation ar e performed and found to be in excellent agreement. A parametric study of all physical parameters is conducted and the results are presented graphically to illustrate interesting f eatures of the solutions. It is found that the chemical reaction order and rate coefficie nt have significant effects on the contaminant concentration profiles. Furthermore, the sc ale-dependent polynomial type dispersion coefficient is predicted to obtain significant ch anges in the contaminant concentration at all dimensionless time stages compared with the constant dispersion case. However, relatively smaller changes in the concentration level are predicted for the exponentially-increasing dispersion coefficient.
10 citations
"Numerical study on kinetic/equilibr..." refers methods in this paper
...The aqueous plume of the contaminant has been modelled numerically in the porous media by a set of governing partial differential equations for non-linear reactive transport (Chamkha, 2007; Clement et al., 2004; Prommer, Davis, & Barry, 2000)....
[...]