Monday, April 20, 2009
Immiscible liquids have proven to be a lasting source of subsurface contamination at many hazardous waste sites. Understanding the transport and fate behavior of these contaminants will allow for better site characterization and determination of applicable remediation technologies. In many cases, contamination will persist after remediation due to several factors, such as residual saturation in inaccessible pore spaces, contaminant in low permeability zones, or contaminant material sorbed to the porous media. Experiments were conducted, at the column scale, to investigate long-term removal of chlorinated solvents from various porous media. Desorption behavior of TCE was examined for ‘aged’ media as well as freshly contaminated media. In addition, experiments were conducted to elucidate dissolution behavior in various porous media. Elution behavior was characterized through monitoring of effluent concentrations over 6 or 7 orders of magnitude. Additionally, synchrotron X-ray microtomography was conducted to characterize the pore-scale morphology of the immiscible liquid as a function of dissolution.