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Vaporization or Chemical Reaction: Which controls the fate of contaminants treated by in situ thermal remediation?
Citation:
DAVIS, E. L. Vaporization or Chemical Reaction: Which controls the fate of contaminants treated by in situ thermal remediation? Presented at The Sixth International Conference, Remediation of Chlorinated and Recalcitrant Compounds, Monterey, CA, May 19 - 22, 2008.
Impact/Purpose:
To perform laboratory experiments and field scale investigations in an effort to determine which chemicals of environmental concern are potentially degradable at thermal remediation temperatures, the rates at which these reactions occur, and the byproducts that are formed.
Description:
Thermal remediation technologies, which includes steam enhanced extraction, electrical resistance heating, and thermal conductive heating, have been developed based on technologies employed by the enhanced oil recovery industry. Although mobilization and/or volatilization of contaminants for their collection and above ground treatment is the basis for these remediation technologies, early deployments seemed to provide evidence that reactions of the contaminants of concern were occurring during the course of the thermal remediation. Subsequent to that, laboratory experiments and field scale investigations have been conducted in an effort to determine which chemicals of environmental concern are potentially degradable at thermal remediation temperatures, the rates at which these reactions occur, and the byproducts that are formed. Controlled laboratory experiments would seem to be the ideal way to study these reactions to obtain a mass balance and a clear understanding of the reactions that take place. However, laboratory experiments at high temperatures are prone to a variety of confounding factors, for example, volatilization losses. Also, complications such as detection methods or limits of the byproducts formed can complicate the analysis of the data. In addition, it is possible that mechanisms can be created in the laboratory that do not occur in the field during thermal remediation. Thus, laboratory experimental procedures must be reviewed critically before accepting the results of these experiments and extrapolating the data to the field.