Abstract: Surfactant-Enhanced Remediation of Saturated Ottawa Sand Contaminated by Ethylbenzene
MATYJASIK, MAREK, and YORAM ECKSTEIN
Surfactant-enhanced
remediation of aquifers contaminated by LNAPLs (light nonaqueous phase
liquids) is based on solubilization as well as mobilization of entrapped
organic compounds. Laboratory column experiments were conducted to evaluate
the feasibility of enhancing mobilization/solubilization of residual
concentrations
of ethylbenzene using non-ionic surfactant solutions. Non-ionic surfactants
which belong to a group of alcohol ethoxylates where used at concentrations
ranging from 0.2% to 2.0%. The solutions were injected into the columns
flushed with distilled water at three levels of
residual
concentration
(40 ppm, 20 ppm, and 3.6 ppm) of ethylbenzene.
Injections of the tested non-ionic surfactants enhanced the dissolution rate of ethylbenzene between eight to twenty times in relation to the treatment with distilled water. Volume of the ethylbenzene mobilized by injection of surfactant solutions was five to ten times greater than volume of ethylbenzene dissolved by pure water.
Results of the laboratory experiments are compared to numerical simulation of surfactant-enhanced aquifer remediation. Numerical solubilization model (Abriola et al., 1993) was modified to simulate experimental conditions of this study. Differences between the results of the laboratory experiments and the numerical simulations indicate the extent of other than solubilization effects, e.g.: desorption and mobilization of light nonaqueous liquid phase of ethylbenzene.
AAPG Search and Discovery Article #90939©1997 AAPG Eastern Section and TSOP, Lexington, Kentucky