&EPA
United States
Environmental Protection
Agency
EPA/540/MR-94/529
January 1995
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
Subsurface Volatilization and Ventilation System®
Brown & Root Environmental
Technology Description: The Subsurface Volatilization and Ven-
tilation System (SVVS*) is an in-situ vacuum extraction/air sparging
and bioremediation technology for the treatment of subsurface
organic contamination in soil and groundwater. The technology,
developed by Billings and Associates, Inc., and operated under a
licensing agreement by Brown & Root Environmental (formerly
Halliburton NUS Corporation), utilizes vapor extraction and
biostimulation to remove and destroy organic contaminants from
the subsurface. Vapor extraction removes the easily strippable
volatile components from the soil and/or groundwater. This re-
moval mechanism is dominant during the early phases of the
remediation. Biostimulation processes dominate the later phases
of the remediation and are used to accelerate the in-situ destruc-
tion of organic compounds in the soil and groundwater. The
developer claims that remediation using the combination of vapor
extraction and biostimulation is more rapid than the use of
biostimulation alone, while generating lower quantities of volatile
organics than vapor extraction technologies. In addition, SVVS®
can remediate contaminants that would not be remediated by
vapor extraction alone (chemicals with lower volatilities and/or
chemicals that are tightly sorbed). These benefits translate into
lower costs and faster remediations.
The technology consists of a network of injection and extraction
wells plumbed to one or more compressors or vacuum pumps,
respectively. The vacuum pumps create the negative pressure to
extract contaminant vapors. Air compressors simultaneously cre-
ate positive pressures across the treatment area to deliver oxy-
gen for enhanced aerobic biodegradation. The system is
maintained at a vapor control unit that houses pumps, control
valves, gauges, and other process control hardware.
Depending on site conditions, subsurface vaporization can be
enhanced via the injection of heated air. In addition, separate
valves may be installed at the manifold of individual reactor lines
or on individual well points for better control of air flow and
pressures in the treatment area. Depending on groundwater
depths and fluctuations, horizontal vacuum screens, "stubbed"
screens, or multiple-depth completions can be applied. The sys-
tem designed for a site is dynamic, allowing positive and negative
air flow to be shifted to different locations in the subsurface so as
to focus and concentrate remedial stresses in specific areas.
Negative pressure is maintained at a suitable level to prevent the
escape of vapors from the treatment area. If air quality permits
require emission control, volatile organic compounds can be
treated by a patent-pending biological filter that uses indigenous
microbes from the site.
Waste Applicability: According to the developer, the SVVS0 is
applicable to sites contaminated with gasoline, diesel fuels, and
other hydrocarbons, including halogenated compounds. The de-
veloper claims that the SVVS* is very effective on benzene,
toluene, ethylbenzene, and xylene (BTEX) contamination. The
technology can be applied to contaminated soil, sludges, free-
phase hydrocarbon product, and groundwater.
Demonstration Results: The SVVS* technology was demon-
strated at the Electro-Voice, Incorporated, (EV) facility in Buchanan,
Ml, between April 1993 and April 1994. Historical activities at the
EV facility included painting, electroplating, and assembling com-
ponents associated with the manufacture of audio equipment. In
1964, EV implemented an automated painting system, and a dry
well was installed to handle some of the liquid wastes generated
from the paint shop. A remedial investigation discovered a sludge-
like material beneath the dry well area contaminated with aro-
matic hydrocarbons and halogenated and non-halogenated volatile
and semivolatile compounds. Some of these organic contami-
nants have migrated to underlying strata.
An SVVS® was installed at the site, based on the concentration
and pattern of contaminants in the vadose zone. The system
consisted of three separately valved rows of alternating vacuum
extraction and air injection wells (Figure 1). There are eleven
vacuum extraction wells and ten air injection wells, each of which
are valved independently for optimum system flexibility and air
flow control.
The primary objective of the SITE Demonstration was to deter-
mine the effectiveness of the SVVS* technology in reducing
volatile organic contamination in the vadose zone. Based on this
objective, the developer claimed that its technology would reduce
the average contamination of seven target analytes in the vadose
zone by 30% over a one-year period.
The seven analytes chosen for the study included benzene,
toluene, ethylbenzene, xylenes, tetrachloroethene, trichloroeth-
ene, and 1,1-dichloroethene. Additional analytes from the soil,
groundwater, and extracted air streams were collected to further
assess the performance and effectiveness of the SVVS* technol-
ogy. These assessments included determining the relative con-
tribution of biodegradation versus vapor extraction, and evaluating
-------
Building
Sta. 9
Building
Building
o
g ^ S85 II
VE 1 AI2 © VE 3
0SS^63 S814
S81(BRE) © w
^fe.
1^1
AI4 VE 5 © AI6 VE 7
0S815 S810 ^-^
/
S81© S82(BRE)
A S89 oooi
VE8S©1AI9 VE10© AI11
OSta.8 1 a f i 4
vcu
Biological
Emissions
Control™
Vacuum Pumf
Air
Injection
Pump
VE14 AI7 VE15 S83(BRE)*VE ITg' AI19 VE20 Q
Sta. 5 Sta.4O Q O Sta"1
O Sta. 3 Sta. 2
OSta. 6
Sta. 7Q
Former
Dry Well
Area
Legend
Injection Well
11 Vacuum Well
© Soil Boring
• Soil Boring
(Brown & Root)
O Pressure Probe Statior
Figure 1. SVVS® configuration at the Electro-Voice Site.
physical and chemical soil properties that may affect the technol-
ogy.
The developer's claims were evaluated by collecting and analyz-
ing soil samples from several locations before implementation of
the technology and after one year of operation. Changes in the
concentration of the seven target analytes were compared be-
tween the two sampling events. In addition to the soil samples,
volatile organics were measured from the vapor extraction wells.
Shutdown tests were used to determine the magnitude and
spatial variability of biodegradation.
Preliminary results from the SVVS® technology demonstration
follow:
• The SVVS® technology greatly exceeded the developer's claim
for a 30% reduction in the seven target analytes over a one-year
period. Data indicated that the overall reductions as determined
from individual boreholes, ranged from 71% to over 99%.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
• As predicted by the developer, the early phase of the remedia-
tion was characterized by higher concentrations of volatile
organics in the extracted vapor stream.
• The shutdown tests indicate that the technology stimulated
biodegradative processes at the site.
An Innovative Technology Evaluation Report (ITER) describing
the complete demonstration will be available in early 1995.
For Further Information:
EPA Project Manager
Paul de Percin
U.S. EPA RREL
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7797
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/540/MR-94/529
------- |