Geophysical and Hydrologic Monitoring of Air Sparging Flow Behavior: Comparison of Two Extreme Sites

Lundegard, Paul D.; LaBrecque, Doug

doi:10.1002/rem.3440080306

Cited by 11 publications

(2 citation statements)

References 6 publications

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“…They reported that air flow was confined to a zone with a 0.3-to 0.6-m radius in homogenous formations. Similar patterns were reported by Lundegard and LaBrecque (1998), who used an electrical resistance tomography system to map air distributions, and McKay and Acomb (1996), who mapped air distributions with neutron logs. In both cases, steady-state air distribution was centered on the injection point with the bulk of the flow occurring within a 0.3-to 1-m radius.…”

Section: Soil Texturesupporting

confidence: 75%

Experimental and Numerical Investigations of Soil Desiccation for Vadose Zone Remediation: Report for Fiscal Year 2007

Ward¹,

Oostrom²,

Bacon³

2008

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SummaryApart from source excavation, the options available for the remediation of vadose zone metal and radionuclide contaminants beyond the practical excavation depth (0 to 15 m) are quite limited. Of the available technologies, very few are applicable to the deep vadose zone with the top-ranked candidate being soil desiccation. An expert panel review of the work on infiltration control and supplemental technologies identified a number of knowledge gaps that would need to be overcome before soil desiccation could be deployed. The report documents some of the research conducted in the last year to address some of these knowledge gaps. This work included 1) performing intermediate-scale laboratory flow cell experiments to demonstrate the desiccation process, 2) implementing a scalable version of Subsurface Transport Over Multiple Phases-Water-Air-Energy (STOMP-WAE), and 3) performing numerical experiments to identify the factors controlling the performance of a desiccation system.Four laboratory experiments were conducted in an intermediate-scale flow cell to demonstrate the desiccation process and assess the impact of the energy balance on the desiccation process. One of the experiments was performed in homogeneous medium-grained sand, while the rest of the simulations were completed in a heterogeneous system with an inclusion of a fine-grained sand zone and varying levels of external insulation. Evaporative cooling was observed in the experiments and generally decreased with increased distance from the gas inlet chamber. Observations of temperature in fine-grained sands in the heterogeneous systems show two local minima associated with the cooling because of evaporation in the adjacent medium-grained sand whereas the second is attributed to evaporative cooling in the fine-grained sand itself. The occurrence of these temperature minima coincided with passage of the desiccation front. Results of the laboratory tests are consistent with the theory showing that the injection of air leads to significant temperature and moisture changes in the porous medium. In all the experiments, the injection of dry air proved to be an effective means for removing essentially all moisture from the test media. The results of this study provide a unique data set that will be used to calibrate the STOMP code for use in the designs of field-scale desiccation systems.To aid in the design and evaluation of desiccation technologies, STOMP-WAE-B has been enhanced with the addition of gas injection/withdrawal wells. The upgraded version of STOMP-WAE-B is now available for scalable execution on multiple processor (i.e., parallel) computers. The parallel version of the simulator is written in pure FORTRAN 90 with embedded directives that are interpreted by a FORTRAN preprocessor. Without the preprocessor, the scalable version of the simulator can be executed sequentially on a single processor computer. The scalable version of the simulator is designated as STOMP-WAE-B-Sc and is expected to find applications in the design and optimization of ...

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Section: Soil Texturesupporting

confidence: 75%

Experimental and Numerical Investigations of Soil Desiccation for Vadose Zone Remediation: Report for Fiscal Year 2007

Ward¹,

Oostrom²,

Bacon³

2008

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“…This is particularly the case when site data suggest that one or more layers may be present in the subsurface that control air distribution. The use of neutron probes, capacitance probes, and electrical resistance tomography to identify aeration zones have all been reported in the literature (e.g., Acomb et al, 1995;Lundegard and LaBreque, 1998). These techniques generally have the ability to detect the presence of air in the subsurface at the "10% by volume" level.…”

Section: Sf 6 Distribution Test (Pt7)mentioning

confidence: 99%

Diagnostic Tools for Integrated In Situ Air Sparging Pilot Tests

Johnson

Amerson

et al. 2001

Bioremediation Journal

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In situ air sparging (IAS) pilot test procedures have been developed that provide rapid, on-site information about IAS performance. The standard pilot test consists of six activities conducted to look for indicators of infeasibility and to characterize the air distribution to the extent necessary to make design decisions about IAS well placement. In addition, safety hazards that need to be addressed prior to full-scale design are identified. Two additional pilot test activities are described in those cases where air distribution must be more precisely defined. The test activities include both chemical tests (tracking contaminant concentrations, dissolved oxygen and tracers) and physical tests (air flow rate and injection pressure, groundwater pressure response).

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Air Sparging for the Treatment of Chlorinated Solvent Plumes

Johnson

Bruce

2010

SERDP/ESTCP Environmental Remediation Technology

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Geophysical and Hydrologic Monitoring of Air Sparging Flow Behavior: Comparison of Two Extreme Sites

Abstract: As a groundwater cleanup technology, air sparging has been shown to be an effective alternative to pump and treat when systems are correctly designed and subsurface conditions are favorable (Bass and Brown, 1995).

Cited by 11 publications

References 6 publications

Experimental and Numerical Investigations of Soil Desiccation for Vadose Zone Remediation: Report for Fiscal Year 2007

Experimental and Numerical Investigations of Soil Desiccation for Vadose Zone Remediation: Report for Fiscal Year 2007

Diagnostic Tools for Integrated In Situ Air Sparging Pilot Tests

Air Sparging for the Treatment of Chlorinated Solvent Plumes

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