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Terra VAC In Situ Vacuum Extraction System
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Terra VAC In Situ Vacuum Extraction System
(1.15MB)
U.S. EPA Superfund Innovative
Technology Evaluation (SITE) Program
In Situ and Ex Situ Soil Vapor
Extraction (SVE)
TERRA VAC
Abstract
SVE is a process that removes volatile organic compounds
(VOCs) and many semi-volatile organic contaminants (SVOCs) in unsaturated
subsurface (vadose zone) soils and soil piles. It is most applicable to
contaminants with a Henry's Law constant of 0.001 or higher, and to soils
with hydraulic conductivities of between 10 -4 and 10 -8
centimeters per second. For in situ systems, vacuum wells are installed;
in ex situ systems, perforated pipes are used to draw a vacuum through soil
piles. Extracted vapors are treated using standard gas treatment technologies.
Terra Vac's system (patented by others and licensed to Terra Vac) was demonstrated
at the Groveland Wells Superfund site in Groveland, Massachusetts, beginning
in December 1987. During the 56 day demonstration, approximately 1,300 pounds
of VOCs, mainly trichloroethene (TCE), were extracted. Average reductions
in soil concentrations were 92 percent for sandy soils and 90 percent for
clays. SVE can be enhanced by soil heating and pneumatic fracturing.
Back to SITE Home Page
Posted July 12, 1999
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