Technology Status Report: In Situ Flushing - CLU-IN

In Situ Flushing Project Summaries
GWRTAC Case Study Database
under reduced interfacial tension conditions was assessed using a capillary and bond number
analysis. The vertical mobility of pooled DNPAL in response to a lowering of interfacial tension was
not assessed.
The field test consisted of injecting a 1 percent surfactant solution into a single injection well for
3.75 days at a rate of 3.8 liters per minute (1 gpm). Groundwater was then extracted from the same
well for 16 days at a rate of 3.8 liters per minute. The extraction phase therefore lasted greater than
four times the injection phase, in an attempt to ensure that all surfactant solution would be
recovered. Sampling of the extracted groundwater, however, indicated that only 34 percent of the
injected surfactant was recovered, and that no increase in TCE concentration was achieved. It was
hypothesized that the low surfactant recovery was due to surfactant sorption to aquifer solids,
precipitation of the surfactant, liquid crystal formation of the surfactant, or some combination of
these processes.
It is important to point out that the propensity for surfactant losses through sorption, precipitation,
and liquid crystal formation were not assessed prior to execution of the field test. Laboratory
methods are available to asses these processes, but were not employed because of difficulties in
shipping aquifer and groundwater samples off site. It is very likely that the field performance of the
surfactant system could have been improved had such laboratory tests been carried out.
Report(s)/Publication(s) (Additional Information Sources):
Rice University, 1997: Technology Practices Manual for Surfactants and Cosolvents, Rice
University, 6100 Main Street, Houston, TX 77005-1892, February 1997
Ground-Water Remediation Technologies Analysis Center
Operated by Concurrent Technologies Corporation
Appendix - Page 110 of 164
Copyright GWRTAC 1998
Revision 1
Tuesday, November 17, 1998