Technology Status Report: In Situ Flushing - CLU-IN

In Situ Flushing Project Summaries
GWRTAC Case Study Database
GWRTAC ID: FLSH0045
Project Name: University of Michigan - Surfactant Remediation of NAPL-Cont
City: Ann Arbor State/Province: MI
Primary GWRTAC Personal
Communication Source
(Name/Organization):
Project Summary:
None
None
Report(s)/Publication(s) (GWRTAC Source):
U.S. Environmental Protection Agency (EPA), April 1995: Status Report: Surfactant
Enhancements, EPA 542-K-94-003, U.S. EPA OSWER (5102W), TIO, Washington, DC, avail. at
www.gwrtac.org
The following is excerpted from U.S. Environmental Protection Agency (EPA), April 1995: Status
Report: Surfactant Enhancements, EPA 542-K-94-003, U.S. EPA OSWER (5102W), TIO,
Washington, DC, avail. at www.gwrtac.org:
Nonionic surfactant (polyoxyethylene (20), sorbitan monooleate (trade name Witconol 2722 or
Tween 80) are being studied as flushing solution for NAPL removal.
Dr. Abriola’s research group has been conducting laboratory and numerical modeling studies to
evaluate the use of surfactants for remediating aquifers contaminated by nonaqueous phase liquids
(NAPLs). This work has been funded by the EPA’s R.S. Kerr Environmental Research Laboratory
and Great Lakes Mid-Atlantic Hazardous Substance Research Center (HSRC). The specific
objectives of this research are to: screen and select surfactants that will enhance the solubility of
NAPLs in water; measure the solubilization of representative NAPLs (e.g., dodecane, PCE, o-DCB)
in aqueous surfactant solutions; quantify the ability of selected surfactants to recover entrapped
NAPLs from soil columns; and develop and evaluate numerical models capable of predicting
surfactant-enhanced solubilization and mobilization of NAPLs in ground-water systems.
Soil column experiments were conducted to test the ability of a nonionic surfactant,
polyoxyethylene (20) sorbitan monooleate (trade name Witconol 2722 or Tween 80), to recover
entrapped dodecane. After injecting a 4% surfactant solution, the concentration of dodecane exiting
the column increased by approximately 100,000 times. Removal of 10% of the residual dodecane
required 0.7 liters of surfactant solution, while comparable recovery without surfactant would have
required 130,000 L of water. Numerical models were developed to explore the optimal surfactant
flushing strategies based on the flow rate, flushing time, and volume of surfactant required to
remove NAPLs from soil columns. Additional studies are underway to investigate the effects of
rate-limited solubilization, NAPL mobilization and sorption on surfactant-based remediation
technologies. No field demonstrations have been conducted to date, but it was anticipated that
these studies will provide the basis for such work.
Report(s)/Publication(s) (Additional Information Sources):
Ground-Water Remediation Technologies Analysis Center
Operated by Concurrent Technologies Corporation
Appendix - Page 93 of 164
Copyright GWRTAC 1998
Revision 1
Tuesday, November 17, 1998