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