Movement and remediation of trichloroethylene in a saturated, heterogeneous porous medium

Oostrom, Mart; Hofstee, C.; Walker, Roland; Dane, J. H.

doi:10.1016/s0169-7722(98)00154-5

Cited by 81 publications

(77 citation statements)

References 16 publications

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“…Cohen and Mercer (1993) list 1-1-1 trichloroethane and tetrachloroethene residual saturation values of 15 to 40% in coarse Ottawa sand. Oostrom et al (1999) give residual TCE saturation values in coarse, medium and fine sands as 22, 20 and 19%, respectively. If fingering had occurred then model resistivity, and consequently calculated residual DNAPL saturation levels, will represent average values for contaminated and uncontaminated material at the scale of a model cell; calculated residual saturations in this instance would therefore be lower than those determined from laboratory bulk samples.…”

Section: Estimation Of Dnapl Saturationmentioning

confidence: 96%

“…HFE-7200 is an extremely difficult liquid to dye, and at the time of this study a suitable dye was not available; visual confirmation of the NAPL flow pathway after the infiltration experiment could not be achieved. Studies by Schwille (1988), Kueper et al (1989) and Oostrom et al (1999) do however indicate that in a saturated homogeneous coarse-grained porous medium DNAPL would be expected to migrate downwards through the column with limited lateral spreading, either as a front or as fingers. In this case, given the density (d) and viscosity (μ) of the DNAPL used, i.e.…”

Section: Experimental Designmentioning

confidence: 98%

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Noninvasive monitoring of DNAPL migration through a saturated porous medium using electrical impedance tomography

Chambers

Loke

Ogilvy

et al. 2004

Journal of Contaminant Hydrology

111

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Electrical impedance tomography was used to monitor the movement of a fluorinated hydrocarbon DNAPL through a saturated porous medium within a laboratory column. Impedance measurements were made using a horizontal plane of twelve electrodes positioned at regular intervals around the centre of the column. A 2D inversion algorithm, which incorporated the cylindrical geometry of the column, was used to reconstruct resistivity and phase images from the measured data. Differential time-lapse images of DNAPL movement past the plane of electrodes were generated by the cell-bycell subtraction of resistivity and phase baseline models from those associated with the DNAPL release stage of the experiment.The DNAPL pulse was clearly delineated as resistive anomalies in the differential time-lapse resistivity images. The spatial extent of the resistive anomalies indicated that, in addition to vertical migration, some lateral spreading of the DNAPL had occurred. Residual contamination could be detected after quasi-static conditions were re-established. Residual DNAPL saturation was estimated from the resistivity model data by applying Archie's second equation. Despite significant measured phase changes due to DNAPL contamination, the differential phase images revealed only weak anomalies associated with DNAPL flow; these anomalies could be seen only in the initial stages of the experiment during peak flow through the plane of electrodes.

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Section: Estimation Of Dnapl Saturationmentioning

confidence: 96%

Section: Experimental Designmentioning

confidence: 98%

Noninvasive monitoring of DNAPL migration through a saturated porous medium using electrical impedance tomography

Chambers

Loke

Ogilvy

et al. 2004

Journal of Contaminant Hydrology

111

View full text Add to dashboard Cite

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“…Crude oil, diesel, trichloroethylene, bitumen and other NAPLs (Fetter 1999;Oostrom et al 1999) contaminate the groundwater/aquifer matrix/vadose zone soil and require costly and protracted environmental engineering techniques in remediation, monitoring and control. Often, NAPLs in a porous/fractured subsurface make macrovolumes (lenses, hydrocarbon traps, ganglia, blobs, streaks, etc.…”

Section: Engineering Motivation In Contaminant Hydrologymentioning

confidence: 99%

“…They act as hydrodynamic encumbrances with respect to a natural or induced groundwater flow. Lehr & Wright (1963), Strack (1989), Kung (1990) and Oostrom et al (1999) studied the winding seepage past such barriers, in a sense similar to cascades of aerofoils or other barriers in classical fluid mechanics (Milne-Thomson 1958). A vertical cross section of such a coarse-material aquifer with imbedded obstacles is shown in figure 2a.…”

Section: Engineering Motivation In Contaminant Hydrologymentioning

confidence: 99%

Accumulation of a light non-aqueous phase liquid on a flat barrier baffling a descending groundwater flow

Kacimov

2012

Proc. R. Soc. A.

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The pioneering solution of Zhukovskii for a steady two-dimensional flow of an ideal heavy fluid with a nonlinear free boundary condition is extended to a Darcian flow of groundwater encumbered by an impermeable barrier. The stoss or/and lee sides of the barrier are covered by a macrovolume of a liquid contaminant. Explicit parametric equations of the sharp interface are obtained by inversion of the hodograph domain. Zhukovskii's gas-finger shape is shown to be a particular case of our new class of free surfaces. For a cap of a light liquid, partially covering the roof, from the given crosssectional area of the cap, the affixes of the conformal mapping are found as a solution of a system of two nonlinear equations. The horizontal width and vertical height of the cap are determined. If the dimensionless incident velocity is higher than the density contrast, then the interface (cap boundary) cusps at its apex. For a relatively small velocity, the interface spreads to the vertices of the barrier, the apex zone remaining blunt shaped. We depict all the relevant domains and plot the flow nets using computer algebra routines.Keywords: nonlinear free boundary problem; two-dimensional flow of heavy ideal fluid -seepage; holomorphic functions; hodograph; conformal mappings Historical motivation from Zhukovskii's solutionThere are very few analytical solutions to the problem of steady two-dimensional motion of an ideal irrotational heavy fluid with a free surface. This is caused by the necessity to satisfy the Bernoulli equationalong an unknown isobaric streamline (free surface). In equation (1.1a), V is the magnitude of the velocity vector V = V e iq , q is the angle that V makes with the horizontal axis x, g = 9.8 m s −2 and y is the vertical coordinate oriented upwards, against gravity.

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“…The fully implicit integrated finite difference code has been used to simulate a variety of multi-fluid systems (e.g., Hofstee et al 1998, Oostrom et al 1997, 1999Oostrom and Lenhard 1998;Schroth et al 1998;White et al 2004). In this section, a brief overview is presented of the governing equations and solution methods.…”

Section: Stomp Simulator and Constitutive Relationsmentioning

confidence: 99%

Carbon Tetrachloride Flow and Transport in the Subsurface of the 216-Z-18 Crib and 216-Z-1A Tile Field at the Hanford Site: Multifluid Flow Simulations and Conceptual Model Update

Oostrom¹,

Rockhold²,

Thorne³

et al. 2006

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Three-dimensional modeling was conducted with layered models to further develop the conceptual model of CT distribution in the vertical and lateral direction beneath the 216-Z-1A tile field and 216-Z-18 cribs and to investigate the effects of soil vapor extraction (SVE). Base case and sensitivity analysis simulations considered migration of dense, nonaqueous phase liquid (DNAPL) consisting of CT and co-disposed organics in the subsurface beneath the two disposal sites as a function of the properties and distribution of subsurface sediments and of the properties and disposal history of the waste. Simulations of CT migration were conducted using the Subsurface Transport Over Multiple Phases (STOMP) simulator.Simulation results support a conceptual model for CT distribution where CT in the DNAPL phase is expected to have migrated primarily in a vertical direction below the disposal trench. None of the simulations predicted that CT in the DNAPL phase would move across the water table below the 216-Z-18 site. Movement of CT in the DNAPL phase across the water table below the 216-Z-1A site was only predicted in simulations with smaller disposal areas and larger volumes, compared to the base case simulation, and in isotropic porous media. Because uncertainties in disposal area and volume exist, movement of CT in the DNAPL phase across the water table in the subsurface below the 216-Z-1A site should be considered as a possibility. However, even if DNAPL moved across the water table in the past, there may not currently be a DNAPL phase in the groundwater beneath the 216-Z-1A site because of dissolution. Results also show that the Hanford 1a geologic unit, located just beneath the 216-Z-1A and 216-Z18 disposal areas, retains more CT DNAPL within the vadose zone during infiltration and redistribution than other hydrologic units. During simulated SVE operations, CT in this unit remained in the subsurface while DNAPL in other layers was effectively removed. Additional characterization of the Hanford 1a unit below the two disposal sites would provide valuable information about the quantity of DNAPL phase CT remaining in the vadose zone. A significant amount of the disposed CT DNAPL may have partitioned to the vapor phase and subsequently into water and sorbed phases. As for the 216-Z-9 site, it is predicted that any continued migration of CT from the vadose zone to the groundwater is likely to occur through interaction of vapor phase CT with the groundwater and not through continued DNAPL migration. The results indicated that SVE appears to be an effective technology for vadose zone remediation, but additional effort is needed to improve simulation of the SVE process through an enhanced understanding of rate-limited volatilization. A total of 34 three-dimensional simulations have been conducted based on a layered EarthVision™ geologic model, which is an interpretation of available geologic data. These simulations consist of one base case simulation and 33 sensitivity analysis simulations. These simulations examined the infilt...

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Movement and remediation of trichloroethylene in a saturated, heterogeneous porous medium

Cited by 81 publications

References 16 publications

Noninvasive monitoring of DNAPL migration through a saturated porous medium using electrical impedance tomography

Noninvasive monitoring of DNAPL migration through a saturated porous medium using electrical impedance tomography

Accumulation of a light non-aqueous phase liquid on a flat barrier baffling a descending groundwater flow

Carbon Tetrachloride Flow and Transport in the Subsurface of the 216-Z-18 Crib and 216-Z-1A Tile Field at the Hanford Site: Multifluid Flow Simulations and Conceptual Model Update

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