Surfactant-Enhanced Remediation of Saturated Ottawa Sand Contaminated by Ethylbenzene
MATYJASIK, MAREK and ECKSTEIN, YORAM, Department of Geology, Kent State University, Kent, Ohio 44242, U.S.A. e-mail: mmatyjas@kentvm.kent.edu, yeckstei@geology.kent.edu
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.
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