Impact of nonaqueous phase liquid (NAPL) source zone architecture on mass removal mechanisms in strongly layered heterogeneous porous media during soil vapor extraction

Yoon, Hongkyu; Werth, Charles J.; Valocchi, Albert J.; Oostrom, Martinus

doi:10.1016/j.jconhyd.2008.05.006

Cited by 20 publications

(13 citation statements)

References 34 publications

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“…For these experiments, the moisture content showed to have no significant influence on the tr while the Henry's constant showed to have no significant influence on the η. The nonsignificance of the moisture content is not in agreement with other published material (Yoon et al 2008;Albergaria et al 2012;Alvim-Ferraz et al 2006) where it is concluded that the moisture content of the soil hinders the SVE process turning it more time consuming. A possible reason for this result can derive the relatively low number of experiments used in the model development.…”

Section: Multiple Linear Regressioncontrasting

confidence: 72%

Multiple Linear Regression and Artificial Neural Networks to Predict Time and Efficiency of Soil Vapor Extraction

Albergaria

Martins

Alvim-Ferraz

et al. 2014

Water Air Soil Pollut

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The prediction of the time and the efficiency of the remediation of contaminated soils using soil vapor extraction remain a difficult challenge to the scientific community and consultants. This work reports the development of multiple linear regression and artificial neural network models to predict the remediation time and efficiency of soil vapor extractions performed in soils contaminated separately with benzene, toluene, ethylbenzene, xylene, trichloroethylene, and perchloroethylene. The results demonstrated that the artificial neural network approach presents better performances when compared with multiple linear regression models. The artificial neural network model allowed an accurate prediction of remediation time and efficiency based on only soil and pollutants characteristics, and consequently allowing a simple and quick previous evaluation of the process viability.

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Section: Multiple Linear Regressioncontrasting

confidence: 72%

Multiple Linear Regression and Artificial Neural Networks to Predict Time and Efficiency of Soil Vapor Extraction

Albergaria

Martins

Alvim-Ferraz

et al. 2014

Water Air Soil Pollut

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“…The presence of these channels is attributed to the formation of viscous fingering when air flows in a water-saturated medium and its sensitivity to pore scale heterogeneity. Yoon et al [293] incorporated the rate limited mass transfer formulation of Miller et al [8] to the STOMP model to investigate the impact of non-equilibrium conditions on soil vapor extraction applications. Jang and Aral [139] also used a rate limited mass transfer approach in a multiphase flow model to investigate the impact of different design parameters of air sparging such as injection rate, under various site conditions.…”

Section: Multiphase Modelsmentioning

confidence: 99%

Interphase mass transfer between fluids in subsurface formations: A review

Agaoglu

Copty

Scheytt

et al. 2015

Advances in Water Resources

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“…While these studies have only explored the individual effect of flow velocity on DNAPL migration, some studies have explored the effect of heterogeneity on DNAPL migration (Oostrom et al 2003;Gerhard and Kueper 2003;Díaz et al 2006;Page et al 2007;Lee et al 2007;Yoon et al 2008). Dekker and Abriola (2000a, b) performed two-phase flow and surfactant-enhanced remediation simulations and found that mean, variance, and vertical correlation of random permeability fields were primarily important in determining organic liquid saturation, which also had significant effects on remediation efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Page et al (2007) conducted intermediate-scale tank experiments to examine the influence of heterogeneity, and found that the PCE migration was largely influenced by the coarser-sand lenses, and the presence of the DNAPL had no apparent effect on the hydraulic conductivity of the porous media. Yoon et al (2008) conducted soil-vapor-extraction simulation in porous media, and concluded that non-aqueous phase liquids (NAPLs) entrapment in high-permeability zones affected mass transfer from trapped NAPL to free NAPL, since gas can be directly delivered to these zones. Yang et al (2013) conducted three-phase flow simulations in the unsaturated zone of a geologically heterogeneous system, and showed that total infiltration mass, front depth, and variability in NAPL spread increased with increasing heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

et al. 2015

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Understanding the migration of dense non-aqueous phase liquids (DNAPLs) in complex subsurface systems is important for evaluating contamination source zones and designing remediation schemes after spill events. Six sandbox experiments were performed to explore the individual effect of flow velocity, and the combined effect of flow velocity and layered lenses on a DNAPL (PCE) migration in porous media. DNAPL saturation was measured using a light transmission system, and saturation distribution was quantified by spatial moments. The experimental results show that large flow velocity significantly promotes lateral and vertical migration of the low-viscosity DNAPL, while when layered lenses exist, the infiltration rate decreases and horizontal spread increases. Migration processes were numerically simulated, and the modelling results tested against experimental results. Furthermore, migration of DNAPLs with different viscosities was simulated to explore the combined effects of flow velocity and geological heterogeneity. Simulation results show that enhanced heterogeneity makes low-viscosity DNAPLs migrate along preferential pathways, resulting in irregular DNAPL morphology. Layered lenses combined with heterogeneity complicate the effect of flow velocity on the migration of low-viscosity DNAPLs by changing percolation paths. Results also demonstrate that flow velocity exhibits relatively little influence on the migration of medium/high-viscosity DNAPLs, which is predominantly controlled by viscosity and heterogeneity. Enhanced heterogeneity has a larger effect on migration behavior. Findings indicate that the migration paths and position of the source zone could change significantly, due to the combined effect of groundwater flow velocity and geological heterogeneity; thus, comprehensive hydrogeological investigation is needed to characterize the source zone.

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Impact of nonaqueous phase liquid (NAPL) source zone architecture on mass removal mechanisms in strongly layered heterogeneous porous media during soil vapor extraction

Cited by 20 publications

References 34 publications

Multiple Linear Regression and Artificial Neural Networks to Predict Time and Efficiency of Soil Vapor Extraction

Multiple Linear Regression and Artificial Neural Networks to Predict Time and Efficiency of Soil Vapor Extraction

Interphase mass transfer between fluids in subsurface formations: A review

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

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