ABSTRACT
The vapor extraction process has been successfully employed at many types of sites as a stand-alone technology, and may also be considered a synergistic technology to other types of in situ subsurface remediation technologies, such as bioremediation and groundwater pump, skim, and treat. Given the significant hydrogeological complexity of porous media and subsequent heterogeneous distributions of immiscible phase contaminants, the design utility of higher-dimensional coupled models is questionable. Higher-dimensional advective air flow models are being used to design vapor extraction systems. Significant modeling and experimental research is needed to further understand immiscible contaminant behavior in the capillary zone and adjacent boundary conditions. The extent of success in field application of vapor extraction is varied, in many cases related to monitoring and interpretive limitations employed before, during, and after the remediation. The net result of these boundary conditions affects the concentrations of hydrocarbon vapors detected using soil gas assessment techniques and the rates of hydrocarbon recovery utilizing in situ vapor extraction.
