Technology Status Report: In Situ Flushing - CLU-IN

In Situ Flushing Project Summaries
GWRTAC Case Study Database
GWRTAC ID: FLSH0014
Project Name: Goose Farm, Plumsted Twp, NJ
City: Plumsted Twp. State/Province: NJ
Primary GWRTAC Personal
Communication Source
(Name/Organization):
Project Summary:
Farnaz Sargazzi
U.S. EPA
Report(s)/Publication(s) (GWRTAC Source):
Internet URL http://www.epa.gov/superfund/index.htm
U.S. Environmental Protection Agency, 1991: Engineering Bulletin In Situ Soil Flushing,
EPA/540/2-91/021, U.S. EPA Office of Emergency and Remedial Response (OERR), Washington,
DC 20460, Office of Research and Development (ORD), Cincinnati, Ohio 45268, 8 pp., October
1991.
The following text is from notes from April 1997 conversation with EPA RPM, July 1998
conversation with former EPA site hydrogeologiest, and from Internet (EPA.gov):
Site is located approximately two miles northeast of New Egypt, New Jersey. Majority of waste
materials (lab packs, 55-gallon drums, bulk liquids) from manufacture of polysulfide rubber and
solid rocket fuel propellant were place into 100 x 300 x 15 foot pit dug through fine sand. ROD
(9/27/85) states groundwater will be extracted via a wellpoint system, treated on site, and reinjected
into the soil. It was estimated that ten pore volumes would be required to remove the
mobile contaminants from the soil and groundwater. Pilot studies were planned during the design
phase to optimize the treatment system components.
RPM (4/25/97) indicates that flushing occurs on a continuous basis. A total of 41 extraction wells
are utilized, pumping an average of 80 gpm. The water is treated aboveground and approximately
85 to 90% of the water is re-injected. The contaminated zone is within the Cohansey Aquifer, and
is contained within a slurry wall, which is approximately 40 feet deep, and keyed into a semiconfining
layer underlying the treatment zone. The confining layer has a vertical hydraulic
conductivity of 10-5 cm/sec. order of magnitude. Two re-injection trenches are located within the
slurry wall, and flush the contaminated zone. Two additional trenches are located outside of the
slurry wall in uncontaminated areas, are are used to control hydraulic gradient only. All trenches
are shallow, and are of variable lengths.
As of July 1998, former site hydrogeologist indicated that approximately two years prior, problems
with the in situ flushing operation occurred at the site. Groundwater samples from wells completed
in the lower aquifer beneath the confining layer began to exhibit high concentrations of benzene.
At this time, all of the groundwater being infiltrated was being directed into the shorter trench within
the slurry wall, due to malfunctioning equipment in the longer trench. It was speculated that the
hydraulic heads in the upper Kirkwood Aquifer, which was the aquifer being targeted for flushing,
had become too high, thus causing downward leakage through the confining layer. Around this
Ground-Water Remediation Technologies Analysis Center
Operated by Concurrent Technologies Corporation
Appendix - Page 27 of 164
Copyright GWRTAC 1998
Revision 1
Tuesday, November 17, 1998