United States
Environmental Protection
Agency
EPA/540/S5-89/003
May 1389
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Technology Demonstration
Summary
Terra Vac In Situ Vacuum
Extraction System
Groveland, Massachusetts
Terra Vac Inc's vacuum extraction
system was demonstrated at the
Valley Manufactured Products
Company, Inc., site in Groveland,
Massachusetts. The property is part
of the Groveland Wells Superfund
site and is contaminated mainly by
trichloroethylene (TCE). Vacuum
extraction entails removal and
venting of volatile organic constit-
uents (VOCs) such as TCE from the
vadose or unsaturated zone in the
ground by use of extraction wells and
vacuum pumps. The process of re-
moving VOCs from the vadose zone
using vacuum Is a patented process.
The eight-week test run produced
the following results:
• extraction of 1,300 Ib of VOCs
• a steady decline in the VOC
recovery rate with time
• a marked reduction in soil VOC
concentration in the test area
• an indication that the process can
remove VOCs from clay strata
This Summary was developed by
EPA's Risk Reduction Engineering
Laboratory, Cincinnati, OH, to
announce key findings of the SITE
program demonstration that is fully
documented in two separate reports
of the same title (see ordering
information at back).
Introduction
Environmental regulations enacted in
1984 (and recent amendments to the
Superfund program) discourage the
continued use of landfilling of wastes in
favor of remedial methods that will treat
or destroy the wastes. The Superfund
program now requires that, to the
maximum extent practicable, cleanups at
Superfund sites must employ permanent
solutions to the waste problem.
The Superfund Innovative Technology
Evaluation (SITE) program is one major
response to the challenge of finding safe
ways to deal with waste sites. Part of the
program includes carefully planned
demonstration projects at certain
Superfund sites to test new waste
treatment technologies. These new
alternative technologies will destroy,
stabilize, or treat hazardous wastes by
changing their chemical, biological, or
physical characteristics.
Under the SITE program, which is
sponsored jointly by the USEPA Office of
Research and Development (ORD) and
the Office of Solid Waste and Emergency
-------
Response (OSWER), the USEPA selects
10 or 12 Superfund sites each year at
which pilot studies of promising
technologies can be conducted. Sites are
chosen to match the effectiveness and
applicability of a particular technology
with specific waste types and local
conditions. The pilot studies are carefully
monitored by the USEPA. Monitoring and
data collection determines how
effectively the technology treats the
wast©, how cost-effectively the
technology compares with more
traditional approaches, and that the
operation can be conducted within all
public health and environmental
guidelines.
The Groveland Wells site was selected
for such a demonstration project for
1987. The site is the location of a
machine shop, the Valley Manufactured
Products Company, Inc., which employs
approximately 25 people and
manufactures, among other things, parts
for valves. The company has been in
business at the site since 1964. As an
integral part of its building-wide operation
of screw machines, the company has
used different types of cutting oils and
degreasing solvents, mainly trichloro-
ethylene, tetrachloroethylene, trans-1,2-
dichloroelhylene, and methylene chloride.
The contamination beneath the shop
apparently is caused by a leaking storage
tank and by former improper practices in
the storage and handling of waste oils
and solvents. The contamination plume is
moving in a northeasterly direction
towards and into the Mill Pond.
The USEPA has been involved since
1983, when the Groveland Wells site was
finalized on the National Priorities List.
The initial Remedial Investigation (Rl) of
the Valley property was carried out by
the responsible party (RP), Valley
Manufactured Products Company, Inc. A
supplemental Rl was conducted by
Valley in the fall/winter of 1987 to
determine more completely the full
nature of contamination at the Valley site.
A source control Feasibility Study was
performed by USEPA to evaluate various
methods for cleaning up or controlling the
remaining contaminants. A Record of De-
cision (ROD) for the site was signed in
October 1988 calling for vacuum extrac-
tion and groundwater stripping.
The Terra Vac system is being utilized
in many locations across the nation. This
report is based on monitoring the Terra
Vac patented vacuum extraction process
(U.S. Patent Nos. 4593760 and 4660639)
at the Groveland Wells site during a four-
and-one-half-month field operation
period, with emphasis on a 56-day
demonstration test active treatment
period. The report interprets results of
analyses performed on samples and
establishes reliable cost and performance
data in order to evaluate the technology's
applicability to other sites.
The main objectives of this project
were:
• The quantification of the contaminants
removed by the process.
• The correlation of the recovery rate of
contaminants with time.
• The prediction of operating time
required before achieving site
remediation.
• The effectiveness of the process in
removing contamination from different
soil strata.
Approach
The objectives of the project were
achieved by following a demonstration
test plan, which included a sampling and
analytical plan. The sampling and
analytical plan contained a quality
assurance project plan. This QAPP
assured that the data collected during the
course of this, project would be of
adequate quality to support the ob-
jectives.
The sampling and analytical program
for the test was split up into a pretest
period, which has been called a
pretreatment period, an active period,
midtreatment, and a posttreatment per-
iod.
The pretreatment period sampling
program consisted of:
• soil boring samples taken with split
spoons
• soil boring samples taken with Shelby
tubes
• soil gas samples taken with punch bar
probes
Soil borings taken by split spoon
sampling were analyzed for volatile
organic compounds (VOCs) using
, headspace screening techniques, purge
and trap, GC/MS procedures, and the
EPA-TCLP procedure. Additional
properties of the soil were determined by
sampling using a Shelby tube, which was
pressed hydraulically into the soil by a
drill rig to a total depth of 24 feet. These
Shelby tube samples were analyzed to
determine physical characteristics of the
subsurface stratigraphy such as bulk
density, particle density, porosity, pH,
grain size, and moisture. These param-
eters were used to define the basic soil
characteristics.
Shallow soil gas concentrations were
collected during pre-, mid-, and post-
treatment activities. Four shallow vacuum
monitoring wells and twelve shallow
punch bar tubes were used at sample
locations. The punch bar samples were
collected from hollow stainless steel
probes that had been driven to a depth of
3 to 5 feet. Soil gas was drawn up the
punch bar probes with a low-volume
personal pump and tygon tubing. Gas-
tight 50-ml syringes were used to collect
the sample out of the tygon tubing.
The active treatment period consisted
of collecting samples of:
• wellhead gas
• separator outlet gas
• primary carbon outlet gas
• secondary carbon outlet gas
• separator drain water
All samples with the exception of the
separator drain water were analyzed on
site. On-site gas analysis consisted of
gas chromatography with a flame
ionization detector (FID) or an electron
capture detector (ECD). The FID was
used generally to quantify the
trichloroethylene (TCE) and trans 1,2-
dichloroethylene (DCE) values, while the
ECD was used to quantify the 1,1,1-
trichloroethane (TRI) and the tetra-
chloroethylene (PCE) values.
The separator drain water was
analyzed for VOC content using SW846
8010. Moisture content of the separator
inlet gas from the wells was analyzed
using EPA Modified Method 4. This
method is good for the two-phase flow
regime that existed in the gas emanating
from the wellhead. See Table 1 for a
listing of analytical methods applied.
The posttreatment sampling essentially
consisted of repeating pretreatment sam-
pling procedures at locations as close as
possible to the pretreatment sampling
locations.
The activated carbon canisters were
sampled, as close to the center of the
canister as possible, and these samples
were analyzed for VOC content as a
check on the material balance for the
process. The method used was P&CAM
127, which consisted of desorption of the
carbon with CSa and subsequent gas
chromatographic analysis.
-------
Table 1. Analytical Methods
Parameter
Grain size
pH
Moisture (110° C)
Particle density
Oil and grease
EPA-TCLP
TOG
Headspace VOC
VOC
VOC
VOC
VOC
VOC
VOC
Analytical Method
ASTM D422-63
SW846* 9040
ASTM D2216-80
ASTM 0696-78
SW846" 9071
F. R. 11/7/86, Vol. 51,
No. 216, SW846"8240
SW846" 9060
SW846"3810
GC/FID or ECD
GC/FID or ECD
SW846"8010
SW846"8010
Modified P&CAM 127
SW846* 8240
Sample Source
Soil borings
Soil borings
Soil borings
Soil borings
Soil borings
Soil borings
Soil borings
Soil borings
Soil gas
Process gas
Separator liquid
Groundwater
Activated carbon
Soil borings
"Third Edition, November 1986.
Process Description
The vacuum extraction process is a
technique for the removal and venting of
volatile organic constituents (VOCs) from
the vadose or unsaturated zone of soils.
Once a contaminated area is completely
defined, an extraction well or wells, de-
pending upon the extent of contamina-
tion, will be installed. A vacuum system
induces air flow through the soil, stripping
and volatilizing the VOCs from the soil
matrix into the air stream. Liquid water is
generally extracted as well along with the
contamination. The two-phase flow of
contaminated air and water flows to a
vapor liquid separator where contam-
inated water is removed. The contam-
inated air stream then flows through
activated carbon canisters arranged in a
parallel-series fashion. Primary or main
adsorbing canisters are followed by a
secondary or backup adsorber in order to
ensure that no contamination reaches the
atmosphere.
Equipment Layout and
Specifications
The equipment layout is shown in
Figure 1, and specifications are given in
Table 2 for the equipment used in the
initial phase of the demonstration. This
equipment was later modified when
unforeseen circumstances required a
shutdown of the system. The vapor-liquid
separator, activated carbon canisters, and
vacuum pump skid were inside the
building, with the stack discharge outside
the building. The equipment was in an
area of the machine shop where used
cutting oils and metal shavings had been
stored.
Four extraction wells (EW1 - EW4) and
four monitoring wells (MW1 - MW4) were
drilled south of the shop. Each well was
installed in two sections, one section to
just above the clay lens and one section
to just below the clay lens. The extraction
wells were screened above the clay and
below the clay. As shown in Figure 2, the
well section below the clay lens was
isolated from the section above by a
bentonite Portland cement grout seal.
Each section operated independently of
the other. The wells were arranged in a
triangular configuration, with three wells
on the base of the triangle (EW2, EW3,
EW4) and one well at the apex (EW1).
The three wells on the base were called
barrier wells: Their purpose was to
intercept contamination, from underneath
the building and to the side of the
demonstration area, before this contam-
ination reached the main extraction well
(EW1). The area enclosed by the four
extraction wells defined the area to be
cleaned.
Installation of Equipment
Well drilling and equipment setup were
begun on December 1, 1987. A mobile
drill rig was brought in and equipped with
hollow-stem augers, split spoons, and
Shelby tubes. The locations of the
extraction wells and monitoring wells had
been staked out based on contaminant
concentration profiles from a previously
conducted remedial investigation and
from bar punch probe soil gas moni-
toring.
Each well drilled was sampled at 2-foot
intervals with a split spoon pounded into
the subsurface by the drill rig in advance
of the hollow stem auger. The hollow
stem auger would then clear out the soil
down to the depth of the split spoon, and
the cycle would continue in that manner
to a depth of 24 feet. The drilling tailings
were shoveled into 55-gallon drums for
eventual disposal. After the holes were
sampled, the wells were installed using 2-
inch PVC pipes screened at various
depths depending upon the character-
istics of the soil in the particular hole. The
deep well was installed first, screened
from the bottom to various depths. A
layer of sand followed by a layer of
bentonite and finally a thick layer of grout
were required to seal off the section
below the clay lens from the section
above the clay lens. The grout was
allowed to set overnight before the
shallow well pipe was installed at the top
of the grout. A layer of sand bentonite
and grout finished the installation.
VOC Removal From the Vadose
Zone
The permeable vadose zone at the
Groveland site is divided into two layers
by a horizontal clay lens, which is
relatively impermeable. As explained
previously, each extraction well had a
separate shallow and deep section to
enable VOCs to be extracted from that
-------
A/
Secondary
Activated
Carbon
Canister
Tank
Truck
Dwells
Vapor-Liquid
Separator
\EW1
Main Extraction
Well
Primary
Activated
Carbon
Canisters
Barrier
Wells
Monitoring
Well
Monitoring
Well
MW1
MW4
Flgurs 1. Schematic diagram of equipment layout.
Table 2. Equipment List
Equipment
Number Required
Description
Extraction wells
Monitoring wells
Vapor~llqu!d separator
Activated carbon
canisters
Vacuum unit
Holding tank
Pump
4 (2 sections each)
4 (2 sections each)
1
Primary: 2 units in
parallel
Secondary: 1 unit
2" SCH 40 PVC 24' total depth
2" SCH 40 PVC 24' total depth
1000-gal capacity, steel
Canisters with 1200 Ib of carbon In
each canister - 304 SS
4" inlet and outlet nozzles
Terra Vac Recovery Unit - Model PR17
(25 HP Motor)
2000-gal capacity - steel
1 HP motor - centrifugal
-------
2" PVC Pipe
"
£S
rr
—
~
^
^ — Bentonite
*2-t Sand
3
12.67'
•« Grout
^2^-— Bentonite
•* Sand
79'
24'
Figure 2. Schematic diagram of an extraction well.
area of the vadose zone above and below
the clay lens. The quantification of VOCs
removed was achieved by measuring
• gas volumetric flow rate by rotameter
and wellhead gas VOC concentration
by gas chromatography
• the amount of VOCs adsorbed by the
activated carbon canisters by
desorption into CS2 followed by gas
chromatography.
VOC flow rates were measured and
tabulated for each well section
separately. The results of gas sampling
by syringe and gas chromatographic
analysis indicate a total of 1,297 Ib of
VOCs were extracted over a 56-day per-
iod, 95% of which was trichloroethylene.
A very good check on this total was
made by the activated carbon VOC
analysis, the results of which indicated a
VOC recovery of 1353 Ib; virtually the
same result was obtained by two very
different methods.
The soil gas results show a con-
siderable reduction in concentration over
the course of the 56-day demonstration
period as can be seen from Figures 3
and 4. This is to be expected since soil
gas is the vapor halo existing around the
contamination and should be relatively
easy to remove by vacuum methods.
A more modest reduction can be seen
in the results obtained for soil VOC
concentrations by GC/MS purge-and-trap
analytical techniques. Soil concentrations
include not only the vapor halo but also
interstitial liquid contamination that is
either dissolved in the moisture in the soil
or exists as a two-phase liquid with the
moisture.
Table 3 shows the reduction of the
weighted average TCE levels in the soil
during the course of the 56-day
demonstration test. The weighted
average TCE level was obtained by
averaging soil concentrations obtained
every two feet by split spoon sampling
methods over the entire 24-foot depth of
the wells. The largest reduction in soil
TCE concentration occurred in extraction
well 4, which had the highest initial level
of contamination. Extraction well 1, which
was expected to have the greatest
concentration reduction potential,
exhibited only a minor decrease over the
course of the test. Undoubtedly this was
because of the greater-than-expected
level of contamination that existed in the
area around monitoring well 3 that was
drawn into the soil around extraction well
1. The decrease in the TCE level around
monitoring well 3 tends to bear this out.
Effectiveness of the
Technology in Various Soil
Types
The soil strata at the Groveland site
can be characterized generally as con-
sisting of the following types in order of
increasing depth to groundwater:
• medium to very fine silty sands
• stiff and wet clays
• sand and gravel
-------
VMW2
EW2
EW4
003
8
Figure 3. Pretreatment shallow soil gas concentration.
Soil porosity, which is the percentage
of total soil volume occupied by pores,
was relatively the same for both the clays
and the sands. Typically porosity, over
the 24-foot depth of the wells, would
range between 40% and 50%. Perme-
abilities, or more accurately hydraulic
conductivities, ranged from 10-4 cm/sec
for the sands to 10-8 cm/sec for the clays
with corresponding grain sizes equal to
10-' mm to 10-3 mm.
Pretest soil boring analyses indicated
in general that most of the contamination
was in the strata above the clay lens, with
a considerable quantity perched on top of
the clay lens. This was the case for ex-
traction well 4, which showed an excel-
lent reduction of TCE concentration in the
medium to fine sandy soils existing
above the clay layer, with no TCE
detected in the clay in either the pretest
or posttest borings (see Table 4). One of
the wells, however, was an exception.
This was monitoring well 3, which con-
tained the highest contamination levels of
any of the wells, and was exceptional in
that most of the contamination was in a
wet clay stratum. The levels of
contamination were in the 200 to 1600
ppm range before the test. After the test,
analyses of the soil boring adjacent to
monitoring well 3 showed levels in the
range of ND-60 ppm in the same clay
stratum. The data suggest that the
technology can desorb or otherwise
mobilize VOCs out of certain clays (see
Table 5).
From the results of this demonstration
it appears that the permeability of a soil
need not be a consideration in applying
the vacuum extraction technology. This
may be explained by the fact that the
porosities were approximately the same
for all soil strata, so that the total flow
area for stripping air was the same in all
soil strata. It will take a long time for a
liquid contaminant to percolate through
clay with its small pore size and
-------
EW2
EW3
EW4
Map View
VMW3
VMW2
VMW4
Figure 4. Posttreatment shallow soil gas concentration.
consequent low permeability. However,
the much smaller air molecules have a
lower resistance in passing through the
same pores. This may explain why
contamination was generally not present
in the clay strata but when it was, it was
not difficult to remove. Further testing
should be done in order to confirm this
finding.
Correlation of Declining VOC
Recovery Rates
The vacuum extraction of volatile
organic constituents from the soil may be
viewed as an unsteady state process
taking place in a nonhomogeneous
environment acted upon by the combined
convective forces of induced stripping air
and by the vacuum induced volatilization
and diffusion of volatiles from a dissolved
or sorbed state. As such it is a very com-
plicated process, even though the
equipment required to operate the
process is very simple.
Unsteady state diffusion processes in
general correlate well by plotting the
logarithm of the rate of diffusion versus
time. Although the representation of the
vacuum extraction process presented
here might be somewhat simplistic, the
correlation obtained by plotting the
logarithm of the concentration of
co'ntaminant in the wellhead gas versus
time and obtaining a least squares best fit
line was reasonably good. This type of
plot, shown in Figure 5, represents the
data very well and is more valid than both
a linear graph or one plotting
concentration versus log time, in which a
best fit curve would actually predict gas
concentrations of zero or less.
-------
Tabla 3. Reduction of Weighted Average TCE Levels in Soil (TCE Cone.
Extraction Well Pretreatment
1 33.98
2 3.38
3 6.89
4 96.10
Monitoring Well
1 1.10
2 14.75
3 227.31
4 0.87
Posttreatment
29.31
2.36
6.30
4.19
0.34
8.98
84.50
1.05
in mg/kg)
% Reduction
13.74
30.18
8.56
95.64
69.09
39.12
62.83
--
Tabls 4. Extraction Well 4-TCE Reduction in Soil Strata
Depth
ft Description of Strata
0-2 Med. sand wlgravel
2-4 Lt. brown fine sand
4-6 Med. stiff It. brown fine sand
6-8 Soft dk. brown fine sand
8-10 Med. stiff brown sand
10-12 V stiff It. brown med. sand
12-14 V stiff brown fine sand w/silt
14-16 M stiff firm-torn clay w/silt
16-18 Soft wet clay
18-20 Soft wet clay
20-22 V stiff brn med-coarse sand
22-24 V stiff brn med-coarse wlgravel
Tabls 5. Monitoring Well 3— TCE Reduction in Soil
Depth
ft Description of Strata
0-2 M. stiff brn. fine sand
2-4 M. stiff grey fine sand
4-6 Soft It. brn. fine sand
6-8 U. brn. fine sand
8-10 Stiff V. fine brn. silty sand
10-12
12-14 Soft brown silt
14-16 Wet green-brown silty clay
16-18 Wet green-brown silty clay
18-20 Wet green-brown silty clay
20-22 Silt, gravel, and rock frag.
22-24 M. stiff It. brn. med. sand
Perme-
autiity —
cm/sec
10'4
W4
10-5
W5
W4
TO'4
10'4
W8
70-8
W8
10'4
10-3
Strata
Perme-
ability —
cm/sec
70-5
10-5
10-*
10'4
W4
70"*
70-8
70-8
70-8
70"»
10'4
TCE Cone, ppm
pre post
2.94 NO
29.90 ND
260.0 39
303.0 9
351.0 ND
195.0 ND
3.14 2.3
ND ND
ND ND
ND ND
ND ND
6.71 ND
TCE Cone, ppm
pre post
10.30 ND
8.33 800
80.0 84
160.0 ND
ND 63
NR 2.3
316.0 ND
195.0 ND
218.0 62
1570.0 2.4
106.0 ND
64.1 ND
-------
100
1
s
o
0.1
0.01
srra-VAC Demonstration Extraction Well #1
Shallow
*
^W-
} — ~~H
— i —
•••^~--^. —
.• •* «"?<.
^^
\,
— —
— ^
•"
Y - 1 59.33 ' EXP (-0-05X)
Curve Coefficient
R2 = o.62
20 40 60
Day of Active Treatment
80
100
Figure 5. Wellhead TCE concentration vs time.
Looking at the plots for extraction well
1, shallow and deep, equations are given
for the least squares best fit line for the
data points. If the vacuum extraction
process is run long enough to achieve
the detection limit for TCE on the ECD,
which is 1 ppbv, the length of time
required to reach that concentration
would be approximately 250 days on the
shallow well and approximately 300 days
on the deep well.
Prediction of Time Required for
Site Remediation
The soil concentration that would be
calculated from the wellhead gas
concentration using Henry's Law is in-
cluded in the last column of Table 6. Cal-
culations for the predicted soil concen-
trations were made assuming a bulk
density of the soil of 1761 kg/m3, a total
porosity of 50%, and a moisture content
of 20%. The calculated air filled porosity
of the soil is approximately 15%. Henry's
constant was taken to be OA92 KPa/m3-
gmol at40°F.
Table 6. Comparison of Wellhead Gas VOC Concentration and Soil VOC Concentration
Extraction Well
TCE Concentration in
Wellhead Gas ppmv
TCE Concentration in
Soil ppmw
Predicted by Henry's
Law ppmw
1S
1D
2S
2D
3S
3D
4S
9.7
5.6
16.4
14.4
125.0
58.7
1095.6
54.5
7.2
ND
20.4
20.9
18.0
9.1
0.11
0.07
0.20
0.17
1.53
0.74
12.49
-------
Given the nonhomogeneous nature of
the subsurface contamination and
interactions of TCE with organic matter in
the soil, it was not possible to obtain a
good correlation between VOC concen-
trations in wellhead gas and soil in order
to predict site remediation times. Henry's
Law constants were used to calculate soil
concentrations from wellhead gas
concentrations and the calculated values
obtained, correcting for air filled porosity,
were lower than actual soil concentrations
by at least an order of magnitude (see
Table 6).
Before one can attempt to make a
rough estimation of the remediation time,
a target value for the particular contam-
inant in the remediated soil must be
calculated. This target concentration is
calculated by using two mathematical
models, the Vertical and Horizontal
Spread Model (VMS) and the Organic
Leachate Model (OLM) (EPA Draft Guide-
lines for Petitioning Waste Generated by
the Petroleum Refinery Industry, June 12,
1987). The mathematical models allow
the use of a regulatory standard for
drinking water in order to arrive at a
target soil concentration.
The VHS model is expressed as the
following equation:
Cy = C0 erf (Z/(2(azY)Q.5)) erf (X/(atY)o.5)
where:
Cy « concentration of VOC at compliance
point (mg/l)
C0 »concentration of VOC in leachate
(mg/l)
erf = error function (dimensionless)
Z = penetration depth of leachate into
the aquifer
Y = distance from site to compliance
point (m)
X = length of site measured perpendic-
ular to the direction of groundwater
flow (m)
at = lateral transverse dispersivity (m)
az = vertical dispersivity (m)
A simplified version of the VHS model
is most often used, which reduces the
above equation to:
Cy = CQCf
where:
Cf =erf (Z/(2(azY)0.5)) erf (X/(atY)0.5),
which is reduced to a conversion
factor corresponding to the amount
of contaminated soil
The Organic Leachate Model (OLM) is
written as:
C0 = 0.00211 CS0.678S0.373
where:
C0 = concentration of VOC in leachate
(mg/l)
Cs = concentration of VOC in soil (mg/l)
S = solubility of VOC in water (rng/l)
The regulatory standard for TCE in
drinking water is 3.2 ppb. This regulatory
limit is used in the VHS model as the
compliance point concentration in order
to solve for a value of the leachate con-
centration. This value of leachate
concentration is then used in the OLM
model to solve for the target soil concen-
tration.
Once the target soil concentration is
determined, a rough estimation of the
remediation time can be made by taking
the ratio of soil concentration to wellhead
gas concentration and extrapolating in
order to arrive ,at a wellhead gas concen-
tration at the target soil concentration.
The calculated target soil concentration
for this site is 500 ppbw. This corre-
sponds to an approximate wellhead gas
concentration of 89 ppb for EW1S. The
equation correlating wellhead gas con-
centration with time (see Figure 15) is then
solved to give 150 days running time.
After 150 days the vacuum extraction
system can be run intermittently to see if
significant increases in gas concentra-
tions occur upon restarting, after at least
a two-day stoppage. If there are no
appreciable increases in gas concentra-
tion, the soil has reached its residual
equilibrium contaminant concentration
and the system may be stopped and soil
borings taken and analyzed.
The full report was submitted in ful-
fillment of Contract No. 68-03-3255 by
Foster Wheeler Enviresponse, Inc., under
the sponsorship of the U.S. Environ-
mental Protection Agency.
10
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The EPA Project Manager, Mary Stinson, is with the Risk Reduction Engineering
Laboratory, Edison, NJ 08837 (see below).
The complete report consists of two volumes entitled "Technology Evaluation
Report: SITE Program Demonstration Test, Terra Vac In Situ Vacuum
Extraction System, Groveland, Massachusetts:"
'Volume I" (Order No. PB 89-192 025/AS; Cost: $21.95, subject to change)
discusses the results of the SITE demonstration
"Volume II" (Order No. PB 89-192 033/AS; Cost: $36.95, subject to change)
contains the technical operating data logs, the sampling and analytical data,
and the quality assurance data
Both volumes of this report will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
A related report, entitled "Application Analysis Report: Terra Vac In Situ Vacuum
Extraction System," which discusses the applications and costs, is under
development.
The EPA Project Manager can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Edison, NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/540/S5-89/003
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