Int. J. Environ. Res. Public Health 2011, 8(6), 2226-2239; doi:10.3390/ijerph8062226
Article

Remediation of Chlorinated Solvent Plumes Using In-Situ Air Sparging—A 2-D Laboratory Study

Received: 1 March 2011; in revised form: 21 May 2011 / Accepted: 10 June 2011 / Published: 16 June 2011
(This article belongs to the Special Issue Advances in Environmental Geotechnics)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: In-situ air sparging has evolved as an innovative technique for soil and groundwater remediation impacted with volatile organic compounds (VOCs), including chlorinated solvents. These may exist as non-aqueous phase liquid (NAPL) or dissolved in groundwater. This study assessed: (1) how air injection rate affects the mass removal of dissolved phase contamination, (2) the effect of induced groundwater flow on mass removal and air distribution during air injection, and (3) the effect of initial contaminant concentration on mass removal. Dissolved-phase chlorinated solvents can be effectively removed through the use of air sparging; however, rapid initial rates of contaminant removal are followed by a protracted period of lower removal rates, or a tailing effect. As the air flow rate increases, the rate of contaminant removal also increases, especially during the initial stages of air injection. Increased air injection rates will increase the density of air channel formation, resulting in a larger interfacial mass transfer area through which the dissolved contaminant can partition into the vapor phase. In cases of groundwater flow, increased rates of air injection lessened observed downward contaminant migration effect. The air channel network and increased air saturation reduced relative hydraulic conductivity, resulting in reduced groundwater flow and subsequent downgradient contaminant migration. Finally, when a higher initial TCE concentration was present, a slightly higher mass removal rate was observed due to higher volatilization-induced concentration gradients and subsequent diffusive flux. Once concentrations are reduced, a similar tailing effect occurs.
Keywords: air sparging; groundwater; contamination; non-aqueous phase liquids; soils; remediation; pollution
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MDPI and ACS Style

Adams, J.A.; Reddy, K.R.; Tekola, L. Remediation of Chlorinated Solvent Plumes Using In-Situ Air Sparging—A 2-D Laboratory Study. Int. J. Environ. Res. Public Health 2011, 8, 2226-2239.

AMA Style

Adams JA, Reddy KR, Tekola L. Remediation of Chlorinated Solvent Plumes Using In-Situ Air Sparging—A 2-D Laboratory Study. International Journal of Environmental Research and Public Health. 2011; 8(6):2226-2239.

Chicago/Turabian Style

Adams, Jeffrey A.; Reddy, Krishna R.; Tekola, Lue. 2011. "Remediation of Chlorinated Solvent Plumes Using In-Situ Air Sparging—A 2-D Laboratory Study." Int. J. Environ. Res. Public Health 8, no. 6: 2226-2239.

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