Low Molecular Weight Low Viscosity Oils

Surfactant-enhanced remediation of hydrophilic NAPLs (i.e., chlorinated hydrocarbons and gasoline fuels) is a more mature field. A brief summary is given below to demonstrate some important observations from surfactant-enhanced remediation of hydrophilic oil-contaminated soils, many of which will be equally germane to hydrophobic oils. Krebbs-Yuill et. al. (1995) highlighted the economic importance of minimizing surfactant losses, maximizing contaminant extraction, and regenerating the surfactant for reuse. Rouse et. al. (1993) showed that proper surfactant selection could greatly reduce surfactant losses (sorption, precipitation) and thus greatly improve system performance. Shiau et. al. (1994) demonstrated that middle phase microemulsions could be formed with chlorinated solvents using surfactants with direct food additive status, and that middle phase systems are much more efficient than simple micellar systems.. Lipe et. al. (1996) and Hasegawa et. al. (1997) showed that air stripping and liquid-liquid extraction could effectively regenerate surfactant systems laden with volatile and nonvolatile compounds, respectively, and that ultrafiltration could be used for surfactant reconcentration. These concepts have been reinforced and the technology proven through numerous field demonstrations, including the following: Traverse City, MI (Knox et. al. 1997, Sabatini et. al. 1997), three studies at Hill Air Force Base, UT (Knox et. al. 1997), and a study at Tinker Air Force Base, OK (Sabatini et. al. 1998).

Thus, surfactant enhanced subsurface remediation is a mature technology for remediating hydrophilic NAPL, as displayed at the field level. These successful field demonstrations provide encouragement for further evaluation of hydrophobic oils with a similar goal of field deployment. To this end, the current research evaluated laboratory batch and column studies for surfactant enhanced remediation of hydrophobic oil contamination, including phase behavior studies, column studies, and evaluating separation processes for remaining hydrophobic oils from surfactant solutions, all which are functions of the NAPL EACN.

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