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NEWS
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TRENDS
A newsletter about soil, sediment, and ground-water characterization and remediation technologies
Issue 36
This issue o/Technology News and Trends highlights "green remediation," the practice of considering
all environmental effects of remedy implementation and incorporating options to maximize the net
environmental benefit of cleanup. The applications in this issue demonstrate increased sustainability
that can be gained through use of renewable energy sources to power treatment systems or through
well-designed biological systems complementing site reuse. Green remediation strategies closely
evaluate a cleanup project's water requirements, material consumption, waste generation, ecosystem
impacts, and long-term stewardship requirements in addition to energy consumption.
Wind-Driven SVE System Extracts VOCs from Landfill
An innovative soil vapor extraction (SVE)
system has operated at the former Ferdula
Landfill site in Frankfort, NY, for the past 10
years. The system relies on wind-driven
vacuum processes rather than electrically
powered air blowers to extract volatile
organic compounds (VOCs) from the landfill.
After a two-year trial beginning in 1998, the
New York State Department of
Environmental Conservation (NYSDEC)
approved long-term use of the SVE system
to address VOC-contaminated soil serving
as a contaminant source within the landfill.
Soil-gas monitoring indicates that
concentrations of contaminants of concern,
primarily toluene and trichloroethene (TCE),
have decreased 91 -94% since implementing
system upgrades in late 2001.
The landfill received industrial waste such as
chlorinated and non-chlorinated solvents
generated during gun manufacturing at the
nearby Remington Arms Company. Wastes
from the wood finishing and metal cleaning
processes were disposed at the landfill from
approximately 1967 to 1975. Subsurface soil
consists of 2-10 feet of a lacustrine sand
underlain by a 75-foot-thick lacustrine silt and
clay unit with fine seams of sand. Ground
water is encountered at a depth of 5-6 feet.
In 1996, the landfill was closed and covered
with a conventionally engineered cap
constructed of clay and a synthetic
membrane. As a second containment remedy,
an upgradient diversion system comprising a
bentonite slurry wall and underdrain was
installed to divert clean ground water away
from the site, thereby reducing the amount of
leachate requiring treatment. Following
downgradient collection, leachate is
discharged to the county wastewater
treatment system.
The SVE system was designed to remove VOCs
from the unsaturated portion of the 1.8-acre
landfill. The system employs a single windmill
to create a vacuum that extracts the VOCs for
aboveground carbon treatment (Figure 1). The
windmill's 12-ft blades reciprocate a single 10-
in air cylinder fitted with check valves that
enable each intake stroke to draw a vacuum
from the landfill vents. In turn, the cylinder
intake piping is attached to a network of nine
gas vents on the landfill cap. Check valves
on both ends of the cylinder allow a vacuum
to be generated during each intake cycle
(both up and down strokes of the windmill),
producing about 85 ft'/hr/mph of vacuum for
each mile of wind speed per hour. Each
cylinder exhaust stroke pushes the extracted
air through carbon canisters before emission
at the top of a 40-ft tower.
The windmill operates at all times with winds
of 3-20 mph. During winds exceeding 20 mph,
a safety feature automatically furls the mill
away from the wind and applies a brake to
suspend operations. In contrast to
continuous operation of air blowers used in
conventional SVE systems, wind
I continued on page 2]
May 2008
Contents
Wind-Driven SVE
System Extracts VOCs
from Landfill
page 1
Integrated Solar and
Wind Energy Powers
Oil Recovery System page 2
Engineered Wetland
Removes Subsurface
Hydrocarbons While
Providing Beneficial
Reuse
Mobile Systems
Provide Solar Energy
in Northern Climates
page 3
page 5
CLU-IN Resources
EPA's Office of Superfund
Remediation and Technology
Innovation recently released a
Green Remediation web site on
CLU-IN. "GR Web" explains
basic principles and objectives
of green remediation and
outlines best management
practices for reducing the
environmental footprint of
cleanup actions. Over coming
months, the site will expand to
describe more details on best
practices and serve as a
clearinghouse for technical
materials, decision-making
tools, site-specific case studies,
and information on related
events and new information
products. Visit GR Web at http://
clu-in.org/areenremediation/.
Information on related "Eco-
Tools" for returning disturbed
lands to ecological reuse is
available at http://www.clu-
in.org/ecotools/index.cfm.
W
Recycled/Recyclable
Printed with SoyCaroia Ink on paper that
contains at toast 50% recycled htwr

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[continued from page 1]
intermittency inherently provides the
pulsed effect typically found to be more
effective in venting operations.
System upgrades were implemented after
the two-year trial operation to increase the
rate of VOC extraction. The area of venting
influence was expanded by installing six
additional vents to supplement the original
three vents. In addition, windmill
performance during low wind (< 5 mph)
was improved by replacing the original
steel blades with aluminum blades as well
as the original four bronze bearings with
steel roller bearings. This reduction in
rotating mass and bearing friction
increased operational intermittency of the
system 50-90% while maintaining a pulsed
effect and increasing the rate of VOC
extraction more than 25%. Remote data
collection systems also were installed to
allow for continuous monitoring.
Soil-gas sampling showed that total VOC
concentrations decreased from over 2,000
mg/m3in 2002 to approximately 175 mg/m3
in 2007. Toluene concentrations in soil gas
decreased from an estimated 1,400 mg/m3
in 2002 to 90 mg/m3 in 2007, and TCE
concentrations decreased from 200 mg/m3
to 56 mg/m3 in the same period. Since
operations began, approximately 1,500
pounds of total VOC mass have been
removed. Treatment emissions have
consistently met New York state standards
for air quality.
The SVE system and auxiliary equipment
require no electricity and are not tied to
the utility grid. Avoidance of electricity
consumption provided a one-year payback
for the $ 14,000 cost of windmill equipment
and installation. Project construction costs
totaled approximately $40,000, including
$23,000 for the building housing the data
collection and treatment systems. In
contrast, capital cost for a conventional
blower-driven SVE system large enough to
achieve the comparable rate of VOC removal
was estimated at nearly $500,000.
Differences in operation and maintenance
(O&M) costs also are significant. Annual
O&M for the wind-driven extraction
system, primarily for oil changes and parts
replacement associated with the windmill,
average below $500. Thirty-year O&M
costs for a conventional SVE system
using a 25-hp air blower were estimated
at $75,000 each year, including $ 15,000 for
164 MWh of electricity.
Figure /. Ferclula landfill gas
extracted by wind-generated
vacuum is treated inside a
150-ft2 building co-located
with the windmill.
Community impacts from the
windmill-powered system are
negligible compared to a
traditional system, which would
have required a larger building
and generated continuous noise
impacting residences within 50
feet of the site. Situated on the
highest point of the property, the
windmill and small treatment
building blend well with the local
farming community.
The SVE system will operate for
at least five more years,
depending on continually high rates of
VOC extraction, or possibly up to 30 years
in support of long-term contaminant
containment provided by the landfill and
ground-water diversion system. Based on
these results, NYSDEC is showcasing the
project as an effective, efficient, and
sustainable strategy for source removal
when combined with long-term
containment actions.
Contributed by Peter Ouderkirk. NYSDEC
(psouderk@gw.dec.state.ny.us or 315-
785-2513) and Sathya Yalvigi, DuPont
(sathya.v.yalvigi@usa.dupont.com or 302-
892-8035)
Integrated Solar and Wind Energy Powers Oil Recovery System
Recovery of free-product petroleum at
the former St. Croix Alumina (SCA) site
in Kingshill on St. Croix, VI, is addressing
ground-water contamination caused by
past releases of fuel and refined
petroleum at SCA. The oil recovery
system employs wind-driven turbine
compressors (WTCs), wind-driven
electric generators (WEGs), and
photovoltaic (PV) panels to power
pneumatic and electric submersible
pumps. By the end of 2007, the system
had recovered approximately 243,000
gallons of free-product oil, which is 21% |
[continued on page 3]

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«tPME
, ''' .	'.V .I
[continued from page 4]
biodegradation and phytoremediation
(including phytovolatilization). Aeration
pipes are flushed periodically with citric acid
to remove mineral deposits that potentially
interfere with air delivery and encourage
algae growth after routine fertilization of
adjacent golf course turf.
Since full-scale operation began in May
2003, hydraulic loading of the system has
averaged 2,600 rP/day (700,000 gal/day).
Concentrations of target contaminants in
ground-water samples collected from the
aerator effluent show benzene and total
BTEX concentrations approximately 50%
lower than in aerator influent.
Concentrations in wetland effluent are below
detectable I imits prior to discharge into Soda
Lake, a basin created by former refinery
effluent discharge.
The engineered wetland was selected over
other in-situ biological strategies, such as
bioremediation or phytoremediation, due to
the need to control hydraulic gradient.
Construction costs totaling $3.4 million
saved an estimated $12.5 million compared
to pumping and treatment using stripping
Figure 4. After two years of growth,
plants covered approximately 50% of the
radial-flow engineered wetland at the BP
site outside Casper.
towers and activated carbon. O&M
consists primarily of sampling, monitoring,
and maintenance of the recovery well
system.
The Wyoming Oil and Gas Conservation
Commission became the anchor tenant of
the new office park in March 2004, ten
months after the full-scale wetland system
began operating. The golf course and
other recreational facilities were completed
in 2005 as surface features of the wetlands
continued to blend with the community
(Figure 4).
Contributed by Vickie Meredith,
Wyoming Department of Environmental
Quality (vmered@state.wy.us or
307-335-6948) and Scott Wallace,
Jacques Whitford NAWE, Inc.
(scott.waHace@iacqueswhitford.com or
651-255-5050)
Mobile Systems Provide Solar Energy in Northern Climates
The Department of Transportation for
Alberta, Canada, is examining innovative
strategies to resolve environmental
issues in remote areas of the province.
Portable units for harnessing solar
energy have been demonstrated over
the past five years as a viable method
for generating the electricity needed to
drive remediation systems at several
sites in western Canada. The typical
mobile system consists of a 21-ft trailer
holding a 2-kW PV array and 1,600-amp/
hr storage battery used to power, as
needed, a 100-psi air compressor,
pneumatic pumps, and air blowers over
short durations.
Applications indicate that solar energy
availability typical to the climate of
southern Alberta (6-8 hours during
summer and 4-6 hours in winter) is
sufficient to power the low to moderate
electricity demands and seasonal work often
involved in remote cleanups. Through use
of the storage battery, however, ample
electricity could be withdrawn for systems
requiring 24-hour operation. Mobile solar
systems were deployed in western Canada
to power equipment such as:
~ Submersible pumps for dewatering
and product skimming at a hydrocar-
bon-impacted site in Beaver River, BC,
from July 2002 to December 2004 (Fig-
ure 5). Use of the full 2-kW PV array
avoided need for a typically high-main-
tenance diesel generator consuming a
large volume of fuel, or alternate instal-
lation of electricity lines extending
to the utility grid at an infeasible cost.
Successful hydrocarbon recovery
prompted plans to install a perma-
nent solar system to fully remediate
and reclaim the site.
Icontinued on page 6]
Figure 5. Portable PV and
remediation equipment was towed
to the Beaver River site and
assembled in less than one day.

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[continued from page 2)
of the 1,136,000 gallons estimated to have
originally been released. SCA operates
the project under a RCRA consent order.
In 1994, EPA became aware of a
subsurface oil plume in the SCA vicinity,
which was later shown by
chromatographic analysis to be caused
by co-mingled petroleum products
released between 1978 and 1991. In
addition to a light non-aqueous phase
liquid (LNAPL) plume floating on ground
water in the Kingshill Aquifer and on
perched ground water, dissolved-phase
petroleum hydrocarbon constituents
were present in ground water. Although
ground water is not utilized at the SCA
facility, the Kingshill Aquifer is used
upgradient of the facility and elsewhere
on the island with less saline conditions.
Consequently, the Kingshill Aquifer is
an important source of drinking water in
some parts of St. Croix.
Wind resource data from the nearby St.
Croix airport showed that the site was
well suited for wind energy applications.
Oil recovery began in 2002 using four
WTCs to drive pneumatic total-fluid
pumps in six recovery wells. Recovered
oil and co-mingled ground water are
pumped to a separation tank where oil
and water are separated via gravity
separation. The oil then is reclaimed and
used as feedstock at an adjacent
petroleum refinery, as permitted under
RCRA, and the water is transferred to a
permitted wastewater treatment system
prior to discharge to the Caribbean Sea.
Each WTC is powered by a windmill with
4.3-ft blades that begin rotating at a wind
speed of 4 mph. When wind speed
exceeds 30 mph, the blades furl and turn
out of the wind. The air compressor is
located directly behind the windmill, on
a hinged tower. For maintenance or
occasional hurricane protection, the
combined blade/compressor unit can be
lowered to the ground. Each WTC is
designed to generate approximately 45 psi
of operating pressure.
A 165-W solar panel array was installed in
2003 to provide electricity for an enhanced
fluid-gathering system. In 2006, two WEGs
were installed to supplement power for
electric submersible total-fluid pumps that
were installed in several wells to increase
oil recovery by the four WTCs. Two
additional WEGs (for a total of four WEGs)
and an additional PV array (220 W) were
installed the following spring to power four
new recovery wells for enhanced
hydrocarbon recovery (Figure 2).
In November of last year, a compressed
air "makeup" line was added to
supplement the air from the WTCs and to
maintain a continuous 55-psi operating
pressure in the pneumatic recovery pumps
when the WTCs are not providing
sufficient air pressure. To date, electricity
from the utility grid still is not required
for the recovery pumps or to collect and
transport the recovered total fluids to the
separation tanks.
The volume of free-product oil recovered
during the second half of 2007, reflecting
the recent system upgrades, averaged 91.5
gal/day. During that period, the recovery
system employed five pneumatic total-
fluid submersible pumps and five
electrically powered total-fluid
submersible pumps. The submersible
pumps recover both free product and
ground water, and enhance the ground-
water gradient to facilitate capture of free
product away from the well bore. Oil
"skimmer" pumps capture the oil layer
in the well bore but do not create an
enhanced gradient for oil to move to the
well bore. Semi-annual fluid gauging and
analysis of ground-water samples from
nine monitoring wells around the
perimeter of the plume indicate that both
the LNAPL and dissolved constituent
plumes are not migrating and remain on
the SCA site.
This treatment design was selected due
to the absence of onsite electricity upon
project startup. SCA estimates that the
system's capital costs (including
installation of WTCs, WEGs, and PV
panels) total nearly $40,000,
approximately half the cost to connect
to the power grid. The WTCs are no
longer manufactured; as a result, future
upgrades may include replacement of the
WTCs due to unavailability of
replacement parts, or custom fabrication
of replacement parts.
Contributed by Tim Gordon, EPA
Region 2 (gordon.timothy@epa.gov
or 212-637-4167)
NSi
N X
r ij
Figure 2. The SCA solar system for
fluid gathering now consists of a
385-W PV array in fixed-tilt position.

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Engineered Wetland Removes Subsurface Hydrocarbons While Providing Beneficial Reuse
British Petroleum (BP) is operating an
engineered wetland to treat petroleum-
contaminated ground water at a 300-acre
site in Casper, WY. Release of petroleum
products during refinery operations from
1908 until 1991 resulted in significant
petroleum hydrocarbon contamination.
Over 44,000 yd1 of LNAPL were removed
by dual-phase recovery wells and oil/water
separators constructed in 1981, but
additional cleanup measures were needed
to address dissolved-phase contaminants.
Augmented by a cascading aeration
system, the engineered wetland is achieving
non-detect concentrations of target
compounds such as benzene, toluene,
ethylbenzene, and xylenes (BTEX) while
allowing concurrent reuse of the property
for commercial and recreational purposes.
In 1998, BP and the City of Casper agreed
to a cleanup strategy accommodating
redevelopment of the site, including a golf
course, office park, riverfront trails, and a
Whitewater kayak course. The plan involved
construction of an engineered wetland
capable of treating up to 11,000 m'/day of
gasoline-contaminated ground water for up
to 100 years while blending into the golf
course. Designs were initiated in 2000, pilot-
scale wetland tests were begun in 2001, and
construction of the full-scale wetlands
project was completed in 2003.
Maximum concentrations of dissolved-
phase hydrocarbons included 330 mg/L
benzene and 530 mg/L total BTEX. The site
is located in alluvial sand and silt deposits
along the floodplain of the North Platte
River. Fluctuations in the river's water level
cause the water table to fluctuate within
the surficial aquifer, creating a "smear zone"
due to remaining LNAPL. The resulting
large mass of petroleum hydrocarbons
sorbed to the aquifer matrix gradually de-
sorbs and dissolves into the water, causing
elevated hydrocarbon concentrations.
Refinery demolition involved excavating and
recycling more than 200 miles of
underground pipes and recovery and onsite
crushing of more than 300,000 tons of
foundation concrete. The concrete was reused
as aggregate for the wetland treatment
system. Construction involved grading of
more than 1 million yd' of soil for the golf
course and installation of more than 60 dual-
phase recovery wells feeding the ground-
water treatment system.
A five-month pilot test was conducted to
refine the final design and establish site-
specific parameters for contaminant
degradation. Test results indicated that
potential iron fouling of the wetland media
could be addressed by including a cascade
aeration system to oxidize iron and a surface-
flow wetland to precipitate it. Testing under
both aerated and non-aerated conditions
demonstrated that ground-water aeration
could degrade recalcitrant compounds 45%
more effectively, based on the increase in first-
order rate constants.
Scaling up from the pilot system required a
1,200-fold increase in reactor volume. Two
center-feed, radial-flow treatment beds were
constructed using crushed foundation
concrete as the subsurface flow-engineered
wetland medium. This configuration
maximized flow distribution at a rate of up to
6,(XX) m'/day. One wetland is 360 feet in
diameter, and the second is 65% smaller
due to space constraints. To withstand
winter temperatures as low as -35 °F, the
cells were insulated with a 6-inch mulch
layer. Emergent facultative wetland plants
such as bulrushes, switchgrass, and
cordgrass were planted in each of the four
treatment cells of both wetlands.
After first passing through an oil-water
separator to remove any remaining free
product, ground water is pumped from
the recovery wells to an aboveground
"forced bed" cascade aerator that
transfers atmospheric oxygen to the
ground water, thereby enhancing
contaminant volatilization and oxidizing
ferrous iron (Figure 3). Off-gas from the
cascade aerator is routed to a soil-matrix
biofiIter to control potential air
emissions of BTEX.
The aerated fluid travels through 60 feet
of pipe 3 feet below ground surface to
one of two free-water surface wetlands
operating in parallel. Residence time in
the free-water surface wetlands is
approximately 0.5 days. From the surface
wetlands, water finally passes through
additional subsurface pipes to the center
of each subsurface radial wetland,
where it radiates under natural
hydraulic conditions toward the
perimeter of four wedge-shaped
treatment zones for additional
[continued on page 5]
To
constructed
lake
Radial wetlands
From oil/water
separator
Cascade
aerator
Free-water
surface wetlands
Figure 3. Following ground-water
pumping, dissolved-phase hydrocarbons
are removed through a series of cascade
aeration and engineered wetland
filtering steps typically taking 2.4 days.

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y
Solid Waste and
Emergency Response
(5203P)
EPA 542-N-08-003
May 2008
Issue No. 36
United States
Environmental Protection Agency
National Service Center for Environmental Publications
PO. Box 42419
Cincinnati, OH 45242
Presorted Standard
Postage and Fees Paid
EPA
Permit No. G-35
Official Business
Penalty for Private Use $300
technoioqt

TRENDS
Icontinued from page 5]
~ An integral 2-hp blower providing air
flow of 250 cfm for SVE addressing
residual hydrocarbons from a pipeline
break at Rocky Mountain House air
base from May to September 2006. So-
lar energy provided sufficient power to
enable the SVE system to increase vola-
tilization and promote biodegradation of
hydrocarbons, while eliminating the
need for routine maintenance and fre-
quent refuelling of diesel generators.
Over the five months of operations, hy-
drocarbon levels in all wellheads were
reduced from concentrations more than
double the "lowest effect level" (LEL)
targeted by the Alberta Ministry of the
Environment to less than 10% of the LEL.
The mobile unit's existing 5-kW
generator for auxiliary power (when
insufficient solar energy is available to
provide constant battery charge) burns
natural gas at a rate of approximately 0.6
m'/hr. Diesel generators becoming
available now offer the "autostart"
compatibility needed in these applications,
at an estimated fuel consumption rate of
1.3 gal/kWh. Diesel cost for transfer of the
mobile unit is estimated at approximately $0.80/
mile, or approximately $200 for a typical
distance of 250 miles. Rental cost for the unit
depends on deployment duration but typically
ranges from $ 1,500 to $ 1,800 each month.
The 2-kW PV array is estimated to produce
approximately 3,650 kWh of electricity
annually in 24-volt direct current, 115-volt
alternating current, or 240-volt alternating
current. Generating the same amount of
power with an electricity generator is
estimated to produce 512 kg of carbon
equivalent or an estimated 12 metric tons of
carbon over the typical 25-year lifespan of
PV units.
Contributed by Fred Bowker, Ministry of
Transportation/A Iberta
(fred. bowker@igov.ab.ca or 780-415-
1263) and Stuart Torr, Worley Parsons
Komex (stuart.torrfcDworle \parsons.com
or 403-247-0200)
Contact Us
Technology News and Trends
is on the NET!
View, download, subscribe,
and unsubscribe at:
http://www.epa.gov/tio
http://cluin.org/newsletters
Technology News and Trends
welcomes readers' comments
and contributions. Address
correspondence to:
John Quander
Office of Superfund Remediation
and Technology Innovation
(5203P)
U.S. Environmental Protection Agency
Ariel Rios Building
1200 Pennsylvania Ave, NW
Washington, DC 20460
Phone: 703-603-7198
Fax: 703-603-9135
EPA Is publishing this newsletter as a means ol disseminating uselul Information regarding Innovative and alternative treatment techniques and
6 technologies. The Agency does not endorse specific technology vendors.

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