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CONTENTS
TVl
Passive Bioventing
Demonstration
Conducted by DOD page 1
Phosphate-Induced
Metal Stabilization
Used for Lead-
Contaminated Soil page 3
New EPA Resources
Available page 3
Thermal Desorption
Removes Range
ofOrganics page 5
TECH TRENDS
IS CHANCING!
March issue of Tech Trends is our
last. This July, the Technology
Innovation Office will publish a
new newsletter that combines
Tech Trends' updates on
innovative soil cleanup
technologies with Ground Water
Currents' updates on innovative
ground-water technologies. The
new bimonthly newsletter will be
mailed out to all of our current
subscribers to Tech Trends and
Ground Water Currents.
1ECH TRENDS
Passive Bioventing
Demonstration
Conducted by DOD
by Sherrie Larson and Ron
Hoeppel, Naval Facilities
Engineering Service Center
Through a series of field pilot tests and
a recent demonstration at Castle Airport
(formerly Castle Air Force Base) near
Merced, CA, the U.S. Department of
Defense (DOD) is evaluating the use of
natural passive bioventing to remediate
unsaturated soils contaminated with
petroleum hydrocarbons. Passive
bioventing frequently has been
demonstrated as cost-effective at sites
lacking the electricity needed to run
electric blowers for conventional
bioventing. Most of these
demonstrations, however, were
conducted in arid regions with deep
unsaturated zones (greater than 100
feet), high permeability, and low
moisture content. The Castle Airport
field demonstration, which was
sponsored by DOD's Environmental
Security Technology Certification
Program, indicated the technology can
be used successfully in a setting with
higher soil moisture and a shallower
unsaturated zone.
Passive bioventing utilizes the difference
between gas pressure in unsaturated soil
and in the atmosphere to move air into
or out of vent wells. This technology
can promote the extraction of any
volatile contaminant from unsaturated
soil by using the natural movement of
soil gas out of vent wells. It is used
most often to enhance soil aeration and
resultant aerobic biodegradation of
organic contaminants in unsaturated
soil.
Once air moves into a soil profile, flow
is delayed and dampened by a natural
resistance of the soil to airflow.
Research has shown that higher rates
of airflow into passive bioventing wells
occur in deep soil profiles with high air
permeability, such as a thick sand zone
above the water table. The presence
of low permeability layers above a zone
with high air permeability is expected to
provide comparable airflow into
shallower unsaturated sandy soils. Such
low permeability layers could be silt and
clay strata or manufactured surface
layers such as asphalt. Tests also have
shown that increased soil moisture will
decrease the air permeability of the soil.
The Castle Airport demonstration took
place between April and October 1998
in an area comprising three moderate-
to high-permeability zones of fine- to
medium-grain sand with minor silt and
gravel deposits. Seasonal precipitation
and irrigation pumping in this area
routinely vary ground-water depth,
which ranges from 10 to more than 70
feet below ground surface (bgs). At
the time of the demonstration, a ground-
water depth of 60 feet and soil moisture
content of 5.8 percent (by weight) were
measured. Analysis of soil and soil
vapor samples indicated petroleum
contaminant concentrations as high as
28,000 mg/kg in the gasoline range and
4,400 mg/kg in the JP-4 jet fuel range.
Soil gas contaminant concentrations
[continued on page 2]
Recycled/Recyclable
PrrrctedwKhSoyfCanolalnkCJlpapeMbat
contains at tesst 50% recydedlibec
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Solid Waste and
Emergency Response
(5102G)
EPA 542-N-02-001
March 2002
Issue No. 44
[continued from page 1]
reached 54,000 parts per million by
volume, with a virtual absence of oxygen
gas due to natural fuel biodegradation.
The demonstration used one 4-inch
diameter vent well with three 10 foot-
long screened and bentonite-plugged
intervals covering a depth range of 25-65
feet bgs. The vent well was equipped
with a one-way, passive valve to
increase the potential radius of influence
(Figure 1). Eight vapor-monitoring
points (VMPs) with multi-depth sensors
were installed in two transects extending
outward from the vent well at radial
distances of 4,8,12, and 16 feet.
Additional VMPs were installed at
greater distances from the vent well in
order to delineate larger radii of
influence or to serve as background
stations in uncontaminated areas.
At ten-minute intervals, a continuous
data logger at each VMP recorded the
ambient temperature, ground-water
elevation, barometric pressure, and rates
of total and screened-interval gas flow
into the vent well. In addition,
subsurface differential pressures and
oxygen concentrations were recorded in
the same frequency at each screened
interval of the VMPs.
Demonstration tests indicated that the
average daily volume of air entering the
bioventing well was 3,400 cubic feet,
with peak flow rates ranging from 5 to
15 cubic feet per minute. These rates
are comparable to or greater than those
encountered in passive bioventing
applications at arid sites with unsaturated
zones over 100 feet deep. Tests
indicated that the one-way valve
increased the vent well's radius of
influence significantly by preventing the
backward flow of oxygenated air from
the well during daily periods of low
atmospheric pressure.
Results also showed that the radius of
influence expanded during longer
operation periods. For example, a 5-
percent oxygen concentration in the soil
gas (the level commonly required to
sustain aerobic microbial metabolism)
was detected at a distance of 16 feet
after 16 days of testing and as far as 42
feet after 52 days. Researchers found
that the low-permeability silt and clay
layers above and below each vented
zone, and a ground cover consisting
primarily of asphalt, aided in driving the
air pressure gradient through the vent
well system. Significant airflow rates
were encountered even in the shallowest
(25-35 feet) screened interval of
the well.
The performance of this technology was
compared to that of
conventional bioventing
with electric blowers,
which had been selected
for soil remediation and
previously tested at this
site under the same
geological andhydrological
conditions. Airflow rates
of the passive system
generally were 80-90
percent lower than those
obtained through the
conventional system.
Operation of the passive
system over an extended
time period is expected to
compensate for this rate
difference. In addition,
twice the number of vent
wells were installed in the
passive system to address
the lower radius of influence commonly
associated with shallow wells.
The costs for passive bioventing were
very competitive with those of the
conventional system. Higher costs for
the installation of additional vent wells in
passive bioventing were balanced by the
system's low operation and maintenance
costs. A total project cost of $300,000
was estimated for each technology, with
a unit cost ranging from $ 1.90 to $2.10
per cubic yard of contaminated soil. At
a site lacking access to electricity,
however, DOD estimates that passive
bioventing could save approximately
$ 100,000, which otherwise would be
spent on the installation of additional
power lines or generators.
These studies show that passive
bioventing is cost-effective for promoting
biodegradation of petroleum-
/continued on page 3]
Figure 1: One-Way Passive Valve System
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[continued from page 2]
contaminated sandy soils at depths of
less than 50 feet when covered by low-
permeability layers. DOD anticipates
additional demonstrations and field tests
during 2002 in eastern regions of the
U.S. with higher levels of soil moisture.
For additional information, contact
Sherrie Larson (Naval Facilities
Engineering Service Center) at 805-982-
4826 orlarsonsl@nfesc.navy.mil.
Phosphate-Induced
Metal Stabilization
Used for Lead-
Contaminated Soil
by Judith Wright, Ph.D., PIMS
NW,Inc., Andrea Leeson, Ph.D.,
and Brian Murphy, U.S.
Department of Defense
Under the Environmental Security
Technology Certification Program, the
U.S. Department of Defense (DOD) is
holding its first field-scale demonstration
of phosphate-induced metal stabilization
(PIMS) in soil. The demonstration is
evaluating the use of PIMS with Apatite
H™ for remediation of lead-
contaminated soil at the Camp Stanley
Storage Activity (CSSA) subinstallation
of the Red River Army Depot in
Boerne, TX. In addition to validating the
technology's effectiveness, the
demonstration will determine its field
costs, assess its regulatory acceptance,
and provide an acceptable alternative to
offsite disposal. Preliminary results
show lead stabilization of all 3,000 cubic
yards of soil treated.
Through simple soil mixing, PIMS
stabilizes metals using a natural and
benign phosphate additive (apatite) that
New EPA Resources Available
> To improve the current "state of the art and science" of soil venting
applications, the Office of Research and Development's National
Risk Management Research Laboratory recently released the
report, Development of Recommendations and Methods to
Support Assessment of Soil Venting Performance and
Closure (EPA/600/R-01/070). The report provides a regulatory
approach for assessing soil venting closure, reviews relevant
literature on gas flow and vapor transport, and summarizes research
on methods for improving venting applications. The complete
report can be downloaded at www.epa.gov/ada/pubs/reports.html.
> The Technology Innovation Office now offers a Field-Based
Geophysical Technologies Online Seminar to assist in site
characterization and remediation. The two-hour seminar addresses
factors to be considered in scoping, executing, and reviewing
projects that involve geophysical instruments and techniques, and
walks viewers through the use of technologies such as resistivity
profiling and ground-penetrating radar. Throughout the seminar,
instructors describe how to apply systematic planning, dynamic
work plans, and field technologies to site cleanups guided by
geophysical tools. To view the most recent seminar or to find out
when future online sessions will be offered, visit www.clu-in.org/
conf/tio/geophysical.
chemically binds soluble metals into
stable, insoluble minerals. Apatite II
holds up to 20 percent of its weight in
lead, uranium, and other metals. Once
the metals are removed by precipitation
from the soil solution and sequestered in
the new apatite phase (within minutes),
the metals are considered stable, i.e.,
with significantly reduced mobility and
bioavailability for geologically long time
periods.
DOD selected onsite stabilization at the
CSSA due to the large volume of
contaminated soil involved, insufficient
space for contaminated soil disposal, the
technology's ability to return the soil to
viable future use, and implementation
costs that were lower than other
technologies considered. Evaluation of
PIMS indicated that it would produce a
stable end-product mineral for the metal
(pyromorphite [Ks ~ 10'80]) and could
be implemented through existing
technology. It also was determined that
PIMS would have little impact on soil
properties and would not affect nearby
wetlands bioremediation activities.
The primary mission of CSSA is the
receipt, storage, issue, and maintenance
of ordnance. Until 1986, an open burn/
open detonation area operated at a
location now known as solid waste
[continued on page 4]
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[continued from page 3]
management unit B-20 (SWMU B-20).
Site investigations at SWMU B-20
indicated that particulate lead occurred
in localized soil zones at concentrations
ranging from 200 to 40,000 parts per
million (ppm) and averaging 3,100 ppm.
SWMU B-20 occupies approximately 35
acres. It is underlain by three soil types
with an average density of 104 pounds
per cubic foot and an average
permeability of 3.3 x 10"1 inches per
second. The area receives
approximately 28 inches of precipitation
annually.
To measure leachate and comply with
regulatory requirements, CSS A
conducted a trial application of the
technology at SWMU B-20 prior to full-
scale operation. The treatment area
was underlain by a landfill-type leachate
collection system with a 2-inch layer of
Apatite n to control the lower boundary
condition. Using a standard backhoe,
approximately 35 tons of Apatite II was
mixed into 500 cubic yards of lead-
contaminated soil to achieve a 5-percent
(by weight) mixture of Apatite II.
(Feasibility study results had indicated
that larger amounts of Apatite II would
not increase performance but would
increase costs significantly, while lower
amounts were difficult to mix evenly into
the soil.) The trial mixture then was
covered with coarse gravel to encourage
infiltration and recharge, to provide a
walking surface for workers performing
periodic maintenance of the system, and
to prevent vegetation growth. Over the
following month, the treatment area was
irrigated heavily at a rate equivalent to its
annual precipitation. Analysis of the
system leachate indicated dissolved lead
concentrations below detection limits
(3 parts per billion).
Based on the trial results, similar
methods were employed to remediate
the remaining 2,500 cubic yards of lead-
contaminated soil at SWMU B-20.
Contaminated, upper layers of soil were
collected from the entire unit and placed
in onsite piles that were mixed with
Apatite II (Figure 2). The mixtures
Figure 2: Soil Mixing for Lead Stabilization
grass
monitoring well
clean topsoil (6 inches)
lead-contaminated soil
mixed with 5% Apatite II
(4 feet)
untreated soil base
were spread into a single 4-foot layer
across approximately one acre, and
covered with 6 inches of clean topsoil
that was vegetated through grass
seeding. Due to the continuous nature
of the PIMS process, the site will be
monitored over the next two years to
assess leadmobiliry, bioavailabiliry, and
leaching behavior. As a result of this
treatment, the State of Texas Natural
Resources Conservation Commission
now classifies the remediated soil at
SWMU B-20 as a class II non-
hazardous material. CSSA estimates a
total cost of $38 per treated ton of soil to
employ PIMS at this site, while offsite
disposal would have cost approximately
$105 per ton.
This technology was deployed in 2001 at
other federal and commercial sites to
remove metals in both soils and ground
water. Examples include the Los
Alamos National Laboratory, NM, for
remediation of depleted uranium-
contaminated soil, and the Success Mine,
ID, for removal of zinc, lead, and
cadmium from tailings-contaminated
ground water.
For more information, contact Dr. Judith
Wright (PIMS NW, Inc.) at 505-670-
5809 orjudith@pimsnw.com, or Dr.
Andrea Leeson (DOD) at 703-696-2118
or andrea.leeson@osd.mil. Contact Ken
Rice (Parsons) at 512-719-6050 or
Ken.R.Rice@parsons.com for detailed
information on the Camp Stanley
demonstration. Details on other PIMS
applications and technology comparisons
are available from Dr. James Conca
(Los Alamos National Laboratory) at
505-699-0468 orjconca@lanl.gov.
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What's New from the
Technology Innovation Office
SPECIAL INSERT TO
TECH TRENDS
The Technology Innovation Office (TIO), a component of EPA's Office of Solid Waste and Emergency Reponse,
was created in 1990 to act as an advocate for new technologies. TIO's mission is to increase the application of innovative
technologies for the characterization and treatment of contaminated waste sites, soils, and groundwater. TIO's newest
products and services and those of partner organizations are listed below. All documents can be viewed or downloaded at
http://clu-in.orgftechpubs.htm. For hard copies, contact 800-490-9198 or 513-489-8190 or fax to 513-489-
8695.
Web Resources
Live Internet Seminars
TIO and our partners continue to host free two-hour Internet Seminars on technical topics related to waste site
remediation. In previous seminars, we have had participants from around the world. Never before has it been this easy to
stay abreast of emerging technical clean-up issues without leaving your desk. Three to four seminars occur every month,
and are announced on the CLU-IN Studio site at http://clu-in.org/studio.
FRTR Perchlorate Page
The Federal Remediation Technologies Roundtable (FRTR) recently posted a website devoted to Federal activities related
to perchlorate in the environment. Major subheadings on the site include: Interagency Committees and Workgroups;
Treatment Technology; Environmental Measurements; Toxicology; Conferences, Workshops, and Presentations on
Perchlorate; Ecosystems; and State Agency Information. For more information, see http://www.frtr.gov/perchlorate.
In Situ Thermal Treatment Site Profile Database (Beta Version)
Recent developments in the area of in situ thermal treatment methods offer the potential for a significantly increased ability to
address subsurface contamination. Approaches to In situ thermal treatment include steam, hot air, or hot water injection,
conductive heating, electrical resistive heating, and radio-frequency heating. These methods are in various stages of
development and deployment, largely as a function of the cleanup problem (size and type of site, location and nature of
contamination) under consideration. The In Situ Thermal Treatment Site Profile Database is an initial attempt
to capture information on sites deploying or planning to deploy these methods. See http://clu-
in.org/products/thermal
New Publications
<=€>=€>=!> Check boxes and fax to 513-489-8695
to order document
n Groundwater Pump and Treat Systems: Summary of Selected Cost and Performance Information at
Superfund-financed Sites (EPA 542-R-01-021a)
This report summarizes Phase 1 (the data collection phase) of the Nationwide Fund-lead Pump and Treat
Optimization Project. Each EPA Region was contacted to identify their Fund-lead pump-and-treat (P&T) systems.
Twenty Fund-lead systems were selected to undergo Remedial System Evaluations (RSEs). This report identifies
the 88 Fund-lead P&T systems, summarizes the information submitted by the EPA Regions, and presents the
screening and selection of those systems to receive RSEs (December 2001, 76 pages).
Remediation Technology Cost Compendium - Year 2000 (EPA 542-R-01-009)
This report provides a summary and analysis of historical cost information for six commonly-applied remediation
technologies: bioremediation, thermal desorption, soil vapor extraction, on-site incineration, groundwater pump-and-
treat systems, and permeable reactive barriers. Cost data were obtained from federal agency sources with data
extracted from approximately 150 projects. (September 2001, 77 pages)
A Citizen's Guide to In Situ Thermal Treatment Methods (EPA 542-F-01 -012)
The Citizen's Guide Series are 2-page fact sheets that provide a general description on approaches to clean up
contaminated waste sites, soil, and groundwater. Each fact sheet answers the questions: What is it? How does it
work? Is it safe? How long will it take? Why use it? This latest guide describes how in situ thermal treatment
removes harmful chemicals from soil by using heat.
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a Improving Sampling, Analysis, and Data Management for Site Investigation and Cleanup (EPA 540-F-01-030a)
and Resources for Strategic Site Investigation and Monitoring (EPA 542-F-01-030b)
These two fact sheets describe EPA's support (A) and resources available (B) for the streamlined approaches to
sampling, analysis, and data management activities conducted during site assessment, characterization, and
cleanup. This position reflects the growing trend towards using smarter, faster, and better technologies and work
strategies. (April 2001, 4 pages/September 2001, 4 pages).
a Using the Triad Approach to Improve the Cost-effectiveness of Hazardous Waste Site Cleanups (EPA
542-R-01-016).
This paper discusses the Triad approach to site decision making, i.e., use of systematic planning, dynamic work
plans, and real-time analysis as the foundation upon which cost-effective, defensible site decisions and actions are
built. A central theme of the triad approach is a clear focus on overall decision quality as the overarching goal of
project quality assurance, requiring careful identification and management of potential causes for errors in
decision-making (October 2001, 8 pages).
a Abstracts of Remediation Case Studies, Volume 5 (EPA 542-R-01 -008)
This report is a collection of abstracts summarizing 56 case studies of site remediation applications prepared
primarily by federal agencies. Abstracts, Volume 5, covers a wide variety of technologies, including full-scale
remediation projects and large-scale field demonstrations of soil and groundwater treatment technologies (May 2001,
168 pages)
o The State-of-the-Practice of Characterization and Remediation of Contaminated Ground Water at Fractured
Rock Sites (EPA 542-R-01 -010)
This report was published in TIO in cooperation with the Ontario Ministry of the Environment and the U.S. Department
of Energy. The report summarizes two conferences held in 2000 on Fractured Rock Sites. The report suggests high
priority characterization and remediation needs to research and development laboratories. It also documents the
current state of the practice.
o Innovations in Site Characterization - Technology Evaluation: Real-Time VOC Analysis using a Field Portable
GC/MS (EPA 542-R-01-011)
This report describes the use of a field GC/MS to measure trichloroethylene on a real-time basis. The results were
effective for making real-time decisions that guided characterization of the plume and optimal placement of the
monitoring wells (July 2001, 32 pages).
Brownfields Publications and Resources - TIO's publications and resources to support Brownfields redevelopment can
be found at http://brownfieldstsc.org.
o Road Map to Understanding Innovative Technology Options for Brownfields Investigation and Clean, Third
Edition (EPA 542-B-01-001)
The third edition of the Road Map has been expanded significantly to include new and updated resources. The
Road Map is not a guidance document. Rather, each section describes the steps involved in the characterization
and cleanup of brownfields sites and connects those steps with available resources. (September 2001, 68 pages)
a Brownfields Technology Primers. The first two installments in a series focusing on technology issues and topics
related to site redevelopment and reuse. "Selecting and Using Phytoremediation for Site Cleanup" (542 R-01-006)
provides information on the use of this technology in a Brownfields setting in a manner understandable to
nontechnical audiences. "Requesting and Evaluating Proposals that Encourage Innovative Technologies for
Investigation and Cleanup" (542 R-01-005) provides information to help localities ensure that procurement efforts
are receptive to innovative approaches.
Videos on the CLU-IN Studio - These videos were produced by the U.S. EPA Environmental
Response Team and deal with selected environmental remediation topics. The videos range in length
from 7-25 minutes. Videos, located at http://clu-in.org/studio, include:
Alabama Oil Burn
Divex
Navajo Vats
Superfund Seniors
Clandestine Drug Labs
Manasota Plating
Summitville Mine
Wyoming Bioremediation
Revegetation with Native Plants
Green Pond Oil Spill
Environmental Dredging
Clean Green - Phytoremediation
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Thermal Desorption
Removes Range of
Organics
byAlCalise, U.S. Air Force
Base Conversion Agency
As part of the National Environmental
Technology Test Sites (NETTS)
Program, the U.S. Air Force Base
Conversion Agency (AFBCA)
completed a pilot-scale demonstration of
ex situ thermal desorption technology at
the former McClellan Air Force Base
(AFB) near Sacramento, CA. Soils
from three sites at the base were treated
to remove a wide range of nonvolatile
and semivolatile organic compounds
(SVOCs), including polycyclic aromatic
hydrocarbons (PAHs), petroleum
hydrocarbons, polychlorinatedbiphenyls
(PCBs), dioxins/furans, and pesticides.
The range of contaminants, together
with low target cleanup goals, made this
demonstration a more stringent test of
the technology than prior applications.
Based on the demonstration results, the
AFBCA is considering full-scale
implementation of thermal treatment as a
remedial option for several hundred
thousand tons of contaminated soil.
McClellan AFB was closed in 2001
after 65 years of operations involving the
use, storage, and disposal of hazardous
materials such as industrial solvents,
caustic cleaners, electroplating
chemicals, heavy metals, low-level
radioactive wastes, fuels, and oils. Site
investigations indicated contaminants in
areas comprising landfills, waste disposal
pits, and spill sites located across the
base. For the contaminants of concern,
concentrations encountered during the
demonstration ranged from non-detect to
a maximum of 5.5 mg/kg for SVOCs
(pentachlorophenol), 0.35 mg/kg for
PAHs (benzo(a)pyrene), 900 mg/kg for
petroleum hydrocarbons (motor oil), 58
mg/kg for PCBs (Arochlor 1260),
40 pg/g for dioxins/furans (2,3,7,8-
TCDD equivalents), and 0.09 mg/kg for
pesticides (4,4'-DDD). Soils in this area
are primarily unconsolidated sediments
with moisture content of 10-14 percent.
Low-temperature (650°F-1,000°F)
thermal desorption relies on heating of
the contaminated soil to temperatures at
which organic compounds will be
liberated through volatilization, leaving
behind the toxic inorganic compounds.
Desorbed organic compounds are
recovered from the carrier gas stream
using scrubbers, condensers, and filters.
Soils to be treated at the McClellan
demonstration site were excavated,
screened to remove oversized material,
and stockpiled on a treatment pad.
After processing through the thermal
desorption unit, treated soils were
returned to the sites of origin.
The demonstration equipment used at
McClellan AFB included an indirectly
heated rotary dryer inside a natural gas-
fired furnace, a screw feed assembly, an
indirect fuel firing system, and a gas
handling unit to supply and capture
nitrogen carrier gas and to condense the
contaminants. Equipment was mounted
on two portable trailers located on the
base's existing soil treatment pad (Figure
3). Although rates varied during testing,
the pilot operation unit was limited to a
maximum soil feeding rate of 1,800
pounds per hour and a maximum
treatment temperature of 1,000°F.
Contaminated soils from three different
sites were treated during the
demonstration. Five days of processing
were performed for each site in two
phases. In the first phase, soils were
treated at 100-degree increments
between 700°F and 1,000°F over two
days to determine the minimum
temperature required for effective
treatment. In the second phase, soil was
treated at a temperature of 1,000°F over
three days to determine the maximum
efficiency of the system. A total of 69
[continued on page 6]
Figure 3: Thermal Desorption System at McClellan AFB
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Tech Trends is on the NET!
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Washington, DC 20460
Phone:703-603-7198
Fax:703-603-9135
[continued from page 5]
tons of contaminated soil was processed
during the 22-day demonstration.
Results indicated that, with the system
operating at its maximum treatment
temperature, concentrations of all
organic contaminants of concern were
reduced to nondetectable levels with the
exception of dioxins/furans that were
reduced to target cleanup goals. PAHs,
SVOCs, and pesticides were removed at
temperatures as low as 700°F, while
nearly complete removal of petroleum
hydrocarbons could be achieved at
temperatures exceeding 800°F. Due to
the difficulty in desorbing residual
dioxins, treatment of soils containing
PCBs and dioxins required temperatures
of 1,000°F to achieve remediation goals.
The AFBCA estimates a cost of $59-
$83 per ton of soil (exclusive of
excavation and backfill costs) for full-
scale thermal treatment using
commercially available systems. System
throughputs are projected to range from
26-46 tons of soil per hour. Other
factors found to impact thermal
treatment include the need for an
appropriate 5-acre treatment pad for
process operation and soil staging, and
for adequate water, gas, and electric
utility connections. Demonstration
results also indicate that treatment of
soils with a moisture content greater
than 20 percent would involve much
higher fuel requirements and lower
throughputs.
To accommodate soil with a higher
moisture content more consistently, full-
scale implementation of this technology
at McClellan AFB would include a
thermal unit with a maximum furnace
temperature of 1,400°F. In addition, the
system would employ a larger, 2-inch
conveyor screen mesh to ensure more
consistent feeding rates, and would
incorporate a treatment system for the
scrubber blowdown to minimize residual
contaminant.
Also under the NETTS Program,
McClellan AFB researchers will
conclude a field-scale soil washing
demonstration early this spring, and have
begun planning additional demonstrations
on soil vapor extraction optimization and
remedial process optimization. For
more information, contact Al Calise
(AFBCA) at 916-643-0830 x. 221, or
e-mailacalise@afbdal.hq.af.mil.
Mention of trade or commercial products does not constitute endorsement by the U.S. Environmental Protection Agency.
(ft)
X^
United States
TECH TRENDS
PRESORTED
FIRST CLASS
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EPA PERMIT NO. G-35
Environmental Protection Agency
National Service Center for Environmental Publications
P.O. Box 42419
Cincinnati, OH 45242
Official Business
Penalty for Private Use $300
EPA542-N-02-001
March 2002
Issue No. 44
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