Technology Status Report: In Situ Flushing - CLU-IN

In Situ Flushing Project Summaries
GWRTAC Case Study Database
GWRTAC ID: FLSH0056
Project Name: Hill Air Force Base (Cell 4, OU 1 - Cyclodextrin Solubilization)
City: Layton State/Province: UT
Primary GWRTAC Personal
Communication Source
(Name/Organization):
Project Summary:
Jon Ginn
U.S. Air Force
Report(s)/Publication(s) (GWRTAC Source):
Rice University, 1997: Technology Practices Manual for Surfactants and Cosolvents, Rice
University, 6100 Main Street, Houston, TX 77005-1892, February 1997
The following text was excerpted from Rice University, 1997: Technology Practices Manual for
Surfactants and Cosolvents, Rice University, 6100 Main Street, Houston, TX 77005-1892, February
1997 and Ground-Water Remediation Technologies Analysis Center (GWRTAC), 1996:
Surfactants / Cosolvents,Technology Evaluation Report TE-96-002, Chad T. Jafvert, Purdue
University, for GWRTAC, Pittsburgh, PA, December 1996, available at www.gwrtac.org:
Hill AFB Operational Unit 1 (OU1) consists of two fire training areas, two chemical disposal pits,
and two landfills. The primary contaminant is LNAPL (light lubricating oils, jet fuel). At OU1, the
design of each test is process dependent, however, each test cell (of nine test constructed test
cells) that will undergo some type of flushing is basically the same. Each cell is constructed of
sheet piling driven into a clay layer approximately 30 feet below the surface, each occupying a
rectangular surface area of 3 m x 5 m. The sheet piling has inter-locking grout-sealed joints to
hydraulically isolate the cell from its surroundings. This type of containment is sometimes referred
to as a Waterloo Barrier system. The poorly sorted sand and gravel aquifer is approximately 15 to
20 ft below the surface to the clay aquitard. Four injection and three extraction wells are located on
the opposite 3 m sides of each cell. Well screens are variable from the clay layer to above the
water table. In the interior are 12 evenly spaced sampling wells, each with nested ports at 5
vertical depths. The saturated zone pore volume (PV) within each cell is variable from 1,000 to
2,500 gallons per cell. The hydraulic conductivity of the saturated potion of the upper sand and
gravel unit at OU1 is 10-1 to 10-2 cm/sec based on aquifer test data, and 10-2 to 10-5 cm/sec
based on slug test data. For all of the flushing experiments (those with surfactants, cosolvents,
and cyclodexdrin), the flushing rate will be approximately one pore volume per day. Prior to and
after treatment of each cell, a partitioning tracer test has or will be performed. The mix of tracers
will be designed according to the expected volume of NAPL within the cell before and after
treatment. Among the tracers, hexanol and dimethylpentanol may be included.
For the test at Cell 6, OU 1, a field trial was conducted using a complexing sugar solution,
beginning in summer 1996. Ten pore volumes of a 10 wt% Hydroxypropyl-B-Cyclodextrin (HPCD)
solution were cycled through a 5 m by 3 m test cell. The mass removal mechanism envisioned is
entrapment and transport of dissolved NAPL consituents within the HPCD molecule. This
mechanism would provide enhanced NAPL solubility. As of February 1997, analysis of the data
collected was underway. Formal documentation of results is anticipated in 1997.
Ground-Water Remediation Technologies Analysis Center
Operated by Concurrent Technologies Corporation
Appendix - Page 115 of 164
Copyright GWRTAC 1998
Revision 1
Tuesday, November 17, 1998