Technology Status Report: In Situ Flushing - CLU-IN

In Situ Flushing Project Summaries
GWRTAC Case Study Database
GWRTAC ID: FLSH0026
Project Name: Laramie, WY, Private wood treating site
City: Laramie State/Province: WY
Primary GWRTAC Personal
Communication Source
(Name/Organization):
Project Summary:
None
None
Report(s)/Publication(s) (GWRTAC Source):
U.S. EPA, Oct. 1991: Eng. Bull. In Situ Soil Flushing, EPA 540-2-91-021, U.S. EPA OERR,
Washington, DC
Mann et al., 1993: Innovative Site Remediation Technology Soil Washing/Soil Flushing, Vol. 3 of
8, WASTECH, William C. Anderson, P.E., DEE, Ed., American Academy of Environmental
Engineers, 1993
Rice University, 1997: Technology Practices Manual for Surfactants and Cosolvents, Rice
University, 6100 Main Street, Houston, TX 77005-1892, February 1997
The following is excerpted from Mann et al., 1993: Innovative Site Remediation Technology Soil
Washing/Soil Flushing, Vol. 3 of 8, WASTECH, William C. Anderson, P.E., DEE, Ed., American
Academy of Environmental Engineers, 1993 and Rice University, 1997: Technology Practices
Manual for Surfactants and Cosolvents, Rice University, 6100 Main Street, Houston, TX 77005-
1892, February 1997. Direct quotes are from Rice, 1997:
"From 1987 to 1990, a suite of in situ remedial technologies were field tested at a former woodtreating
facility in Wyoming where a shallow alluvial aquifer had become contaminated with
creosote based waste wood-treating oils (density 1.03 g/cms, viscosity 54 centipoise). A primary
component of these studies was the analysis of chemically enhanced recovery of the oils. This
involved laboratory testing followed by a small-scale field demonstration in 1988 (Sale, et al.,
1989) and a large-scale field demonstration in 1989 (Pitts, et al., 1993)."
The 100-acre site contained over 500,000 yd3 PAH-impacted alluvial deposits, with significant
DNAPL and LNAPL. The contaminated zone is contained by underlying shale aquitard, a
perimeter bentonite slurry wall, and a negative hydraulic gradient. A 12 foot deep test cell was
isolated from surrounding alluvium aquifer by 27 x 27 foot sheet-pile wall. Alluvial sediments
graduated from fine sands, silts, and clays at surface to coarse sands and fine gravels at base.
The lower three feet of alluvium was saturated by waste wood-treating oil of density 1.04 g/cm3
and viscosity 54 Cp. Delivery and recovery of flushing solution was accomplished through 4-inch
horizontal drain lines spaced 15 feet apart in parallel and located at the alluvium-bedrock contact.
One pore volume (PV - volume of liquid required to saturate the cell) was estimated at 5,000
gallons. (Mann, 1993).
The pilot test sequence consisted of three steps: waterflooding, soil flushing, and reconditioning. In
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Appendix - Page 55 of 164
Copyright GWRTAC 1998
Revision 1
Tuesday, November 17, 1998