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/A newsletter about soil, sediment, and ground-water characterization and remediation technologies
September 2004
Issue 14
Wind Turbine Powers Ground-Water Circulation Well
Liitial findings from a study conducted by the
University of Missouri-Rolla (UMR) show that
wind turbines provide technically effective and
cost-efficient power for small remediation
systems such as ground-water circulation wells
(GCWs). Demonstration of this technology is
underway at the former Nebraska Ordnance
Plant Superfund site near Mead, NE. Analysis
of data collected over the first five months of
operation indicates that the technology is
generating more energy than consumed by
principal components of the GCW. The wind
turbine operates in a utility grid "inter-tie" mode,
whereby both utility and wind energy are used
when wind energy is insufficient. When excess
wind energy is produced, the surplus returns to
the utility grid for other consumer use.
Data collected in 1995-1999 at a utility monitoring
station near the demonstration site indicated an
average wind speed of 6.4 m/s, a wind shear
exponent of 0.27, and a turbulence intensity of
0.17-0.21. Performance modeling using these data
indicated that a single 10-kW turbine installed
on a 100-foot tower would meet the treatment
system's anticipated energy demand. The turbine
was installed in December 2003 (Figure 1) and
connected to the facility's existing electrical
power system the following month for
preliminary testing.
The demonstration employs a 10-kW wind
turbine 53'stem providing energy to power a single
GCW. The well is equipped with an air stripper to
remove trichloroethene (TCE) present in ground
water at concentrations averaging 2,500 ug/L [see
October 2001 issue of Ground Water Currents,
available at www.cluin.org]. The site is underlain
by an unconfined and relatively prolific sand and
gravel aquifer with a saturated thickness of
approximately 90 feet.
The treatment system includes a 12-inch,
108-foot deep circulation well with two
hydraulically isolated screened intervals
separated by a 19-foot unscreened interval. The
well operates at an average flow rate of 50 gpm
on a continuous basis, with the exception of
occasional but temporary shutdowns. Primary
electrical machinery of the system consists of a
1.5-hp submersible pump that extracts water from
the aquifer and delivers it to a 5-hp air stripper,
and a 1 -hp centrifugal pump that returns treated
water from the stripper sump to the well. Historical
data for the GCW, which has operated since July
2000, show little correlation between the amount
of purchased energy and the volume of treated
ground water. This is a result of environmental
control systems used to keep the principal GCW
components from overheating in the summer or
freezing in the winter.
Over the initial five months of the study, the
average monthly electricity demand by principal
components of the GCW was 767 kW-hr. On
average, 817 kW-hr of electricity were generated
by the wind turbine each month. More than 4
million gallons of water were treated by the system
and an estimated 63 kg of TCE were removed
from ground water during the same time period.
Data analysis shows that the treatment system
is removing approximately 21 mg of TCE per
kW-hr of energy generated by the turbine.
Researchers estimate that the use of wind power,
coupled with a well-designed climate control
system, may result in a present-worth energy
cost savings of more than $40,000 over the 20
[continued on page 2]
Contents
Wind Turbine Powers
Ground-Water
Circulation Well
page 1
EPA/ORD and Region 8
Evaluate In-Situ Treatment
of Acidic Mine Pit Lake page 2
Defining a NAPL Source
Zone Using Field Data page 3
Superfund Document
Management System
Used in Columbia Space
Shuttle Recovery page 4
EPA/ORD/NRMRL
Publishes Study
on MNA Performance page 6
CLU-IN Resources
The Federal Remediation Tech-
nologies Roundtable (FRTR) is
an interagency collaboration
for actively sharing information
on hazardous waste site clean-
up technologies and the remed-
iation marketplace. Updates on
FRTR activities and recent pub-
lications issued by its member
agencies are continuously
added to the FRTR web site
(http://www.frtr.gov). Currently,
online access is available for
361 technology cost and
performance reports, 144 site
characterization and monitoring
case studies, 73 remediation
process optimization case
studies, and 54 remediation
technology assessment reports.
Recycled/Recyclable
Printed with Soy'Canola Ink on paper thai
contains al least 50% recycled fiber
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[continued from page 1]
years of ground-water treatment anticipated
at this site.
Similarly sized off-grid wind turbine sy stems,
including installation, cost approximately
$45,000. The cost effectiveness of wind-
powered remediation technology is expected
to be higher in remote areas where installation
of utility lines would incur additional
expenses, on the order of $5,000-$ 10,000.
Beneficial use of this technology is enhanced
by its reliance on renewable resources, rather
than non-renewable fossil fuel, and the
absence of air emissions during deployment.
UMR researchers determined that the
technology is applicable to areas with Class 3
or more wind resources, as classified by the
U. S. Department of Energy scale of 1 -7. Class
3 wind power density is defined as 150-200
W/m2 at a height of 10 m and mean wind
speeds of 5.1-5.6 m/s. Other limiting
application factors may include the proximity
of trees and buildings that could reduce
Figure 1. The 10-kWwind turbine system
erected at the former Nebraska Ordnance
Plant is possibly the technology's "first-
ever " application for remediation
purposes.
effective wind speed at a turbine, and sensitive
land use areas where sound generated by the
rotating turbine blades may be intrusive.
This project was funded by the U.S. EPA's
Office of Solid Waste and Emergency
Response through its Innovation Work Group
grant program, with additional support from
UMR, the Kansas City District Corps of
Engineers, Sergey Wind Systems, and Ohio
Semitronics. Potential follow-on work involves
operation of the GC W intermittently using a
stand-alone wind turbine system that uses
batteries to store energy for use during periods
of low or no wind.
Contributed by Curt Elmore, P.E., Ph.D.,
University of Missouri-Rolla (573-341-6784
or elmoreac@umr.edu)
EPA/ORD and Region 8 Evaluate In-Situ Treatment of Acidic Mine Pit Lake
Over the past three years, the Anchor Hill
Pit at the Gilt Edge Mine NPL site near
Deadwood, SD, has been the site of a joint
effort by EPAs Region 8 Superfund Remedial
Program and the Office of Research and
Development's Mine Waste Technology
Program (through an interagency agreement
with the U.S. DOE). The project aimed to
demonstrate and evaluate an innovative in-
situ process for treating approximately 70
million gallons of acidic mine water containing
high levels of dissolved metals, selenium,
nitrate, and sulfate. EPA estimates that in-situ
use of this technology avoided 20-50% of
the operational costs associated with a
conventional water treatment plant. Full-scale
use is anticipated to help meet state standards
for discharge of treated water to surface water.
The first step of this treatment process
involved neutralizing the pit water to a pH of
approximately 7. Neutralization was achieved
by dispersing lime through a Neutra-Mill, a
floating slaker similar to equipment commonly
used to mix and disperse reagents at water
treatment plants. The second step was to add
nutrients such as methanol, feed-grade
molasses, and phosphoric acid to the pit using
Redox-Mediated Biotransformation (RMB™)
technology. This process stimulated
indigenous bacterial activity that
electrochemically reduced nitrate to nitrogen
gas and subsequently reduced selenium and
sulfate. Reduction of sulfate to sulfide
decreased dissolved-phase metal
concentrations through formation of metal
sulfide precipitates. The stability of metal
sulfides that settled to the bottom of the pit
was maintained in a permanent anoxic zone.
Neutralization of the pit occurred between
March and May 2001. After several weeks of
stabilization, four nutrient additions were made
at 5- to 6-month intervals. Sodium hydroxide
was included in the last two additions to
address an unanticipated but significant
reduction in pH (from 7 to 5) during the post-
neutralization stabilization period.
Bacterial growth during redox treatment
proceeded more slowly than expected due to
below-optimum pH conditions at the process
onset. Incorporation of wood chips in the final
nutrient addition in September 2002 provided
a successful substrate for increased bacterial
growth. Raising the pH level also helped
reduce die amount of dissolved aluminum in
solution, which apparently inhibited
denitrifying bacteria.
Nitrate concentrations continued to decrease
through the winter of 2002-2003, with
nondetectable levels observed by March
2003. Efforts were undertaken at that time to
expedite sulfate reduction. Strings of porous
bags filled with wood chips were suspended
throughout the pit water column. In addition,
porous bags of wood chips were placed on the
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ice surface and allowed to sink to the bottom
upon melting. Consideration was also given to
developing an inoculum of sulfate-reducing
bacteria in adjacent tanks. During installation
of the porous bags of wood chips, however,
observation of black precipitates and a slight
hydrogen sulfide odor suggested that sulfate
reduction had slowly begun prior to these
efforts.
Chemical analysis confirmed sulfate reduction
in the pit and significantly decreased
concentrations of dissolved-phase metals in
the treated water (Figure 2). Treatment
effectively reduced dissolved-phase
concentrations of copper from 43.3 to 0.008
mg/L, cadmium from 14.1 to 0.0.003 mg/L, and
zinc from 14.1 to 0.044 mg/L. Similarly,
concentrations of selenium decreased from 26
to 12 mg/L, nitrate/nitrite dropped from 82.9 to
0.4 mg/L, and sulfate dropped from 3,270 to
2,175 mg/L. An alkalinity increase to
approximately 400 mg/L in the deeper water
provided indirect evidence that biological nitrate
and sulfate reduction had occurred. Monitoring
of the pit over the pastyear indicated continued,
slow settling of the suspended metal sulfides.
Recent efforts have focused on transitioning to
an operational mode involving possible use of
the pit to treat acid mine water across the entire
Gilt Edge site. Over the course of treatment, the
pit lake has become permanently stratified
whereby a strong density gradient (or
"chemocline") at a depth of approximately 25-30
feet separates the upper layer from the lower
layer. Acid rock drainage will be added with
nutrients to the pit at depths below the
chemocline, where the water column is expected
to maintain anoxic conditions. Following
treatment, water below the chemocline will be
removed from the pit, filtered, and aerated to
meet state ambient water quality requirements
for discharge to surface water.
Figure 2. Dissolved-phase concentrations
of metals in acid mine water at the Gilt
Edge Mine fell more than 99% following
denitrification with the onset ofsulfate
reduction.
Modifications to this technology are required
prior to beginning the operational mode. Fine
suspended metal sulfide precipitates in the
deep-pit water, for example, require improved
methods for filtering. Similarly, improved
methods are needed for aerating filtered water,
which contained fine particles of elemental
sulfur due to oxidation of excess dissolved
sulfide. High concentrations of dissolved
hydrogen sulfide in the deep water also will
need resolution to ensure no health and safety
issues exist during aeration. Future plans
include development of a real-time monitoring
system in the pit for continuous observation
of water column hydrodynamics and
geochemistry, particularly when feeding
contaminated water to the deep portion of the
pit.
Contributed by Ken Wangerud,
EPA/Region 8 (303-312-6703 or
wangerudken@epa.gov), Norma Lewis,
EPA/National Risk Management
Research Laboratory (513-569-7665 or
lewis.nortna@epa.gov), and Brian Park,
MSE Technology Applications, Inc.
(406-494-7415 or brian.park@jrise-ta.com)
Defining a NAPL Source Zone Using Field Data
s Region 1 and Office of Research
and Development (ORD) are working with
a group of PRPs to address dense
nonaqueous phase liquid (DNAPL) at the
Solvents Recovery Services (SRS) site in
Southington, CT. Differences between the
conceptual site models (CSMs) developed
by the two organizations prompted an
intensive field program in November 2003
to delineate the DNAPL source zone and
refine the estimated volume of overburden
contaminated with DNAPL. Earlier
evaluations, which potentially supported a
technical impracticability (If) waiver based
on drinking water standards, estimated that
more than 200,000 yd3 of DNAPL-
contaminated soil existed in addition to
800,000 yd3 of residual DNAPL zones in the
overburden aquifer. Based on the results of
a follow-on field investigation, however, the
combined volume of residual and pooled
DNAPL-contaminated overburden to be
evaluated for treatment is now estimated at
45,000yd3.
Between 1955 and 1991, 60-100 million
gallons of spent solvents were processed
on a 4-acre parcel at the SRS site. Liquid
waste was brought to the site in steel drums
and tank trucks, and other wastes were
managed in aboveground tanks. Still
bottoms and sludge were placed in two
unlined lagoons that occasionally
overflowed and discharged into the nearby
Quinnipiac River via an unlined drainage
ditch. A12-acre ground-water contaminant
[continued on page 4]
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[continued from page 3]
plume is present in the overburden, which
consists of 15-50 feet of fluvio-glacial
sediment and till. A slightly larger plume
exists within the underlying fractured
bedrock-a thickly-bedded, red, arkosic
Triassic sandstone. The plume in the
overburden ground water has affected two
municipal water supply wells located 1,300
and 2,000 feet south of the site.
The initial estimate of 200,000 yd3 was based
on the visual observation of DNAPL,
historical records, and indirect indicators,
such as ground-water samples exceeding
1 % of the DNAPL's effective solubility. The
field program assessed whether a
ground-water sample containing 10% of
the effective solubility indicated that a
DNAPL residual or free-phase mass was
immediately upgradient or just "somewhere"
upgradient.
The field program involved advancing 39
borings over a one-week period. Two direct-
push rigs ran continuous cores to the point
of refusal, which was commonly at the top
of bedrock or till. Refusal was encountered
about 15 feet below ground surface on the
west side of the site, becoming
progressively deeper (30-35 feet) to the east.
DNAPL was judged to be present in a core
if it was directly observed or if a hy drophobic
dye indicated its presence in soil samples.
The plastic liners of each core were cut in
half lengthwise, visually inspected, and
Figure 3. Based on the results of field tests,
EPA now estimates that 45,000 yd3 of
DNAPL-contaminated overburden at the SRS
site require remediation.
screened with a photoinonization detector
(PTD). If the PID reading in any part of the
core exceeded 100 ppm, the core was tested
in a 40-mL vial containing equal portions of
soil, water, and hy drophobic dye. The
formation of a red "collar" around the top of
the vial after vigorous shaking indicated the
presence of residual DNAPL in soil.
DNAPL was not observed in areas where
previously its presence was implied only by
indirect indicators such as dissolved-phase
concentrations. Data collected during the field
program were integrated into an updated
C SM that now reflects a much smaller source
zone (Figure 3). Based on the results of this
field investigation, which was estimated to
cost less than $ 1OOK, a TI waiver for cleanup
in the overburden is no longer probable.
Updates to the CSM will continue as remedial
alternatives for the overburden are evaluated
and implemented. A feasibility study is
underway to evaluate the use of
bioremediation, enhanced bioremediation,
thermal treatment, chemical oxidation,
and hydraulic flooding in treating
the overburden. Pilot testing of
phytotechnology began in 2002 with the
planting of poplar trees.
A pump and treat system is in place to
address contamination in the bedrock.
In addition, the potential for natural
attenuation is being evaluated through
analysis of native microbial
(Dehalococcoides) populations in
Geoprobe® soil samples. Additional field
tests will be conducted to evaluate the extent
of DNAPL contamination in bedrock and to
support any associated determination
regarding a TI waiver.
Contributed by Karen Lumino, EPA'
Region 1 (617-918-1348 or
lumino.karen@epa.gov) and Steve
Mangion EPA/ORD (617-918-1452 or
mangion.steve@epa.gov)
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ITENTIAL AREA FOR ff \ / ?
POTENTIAL
SOURCE ZONE TREATMENT-^
Ground-water samples exceeding 10% DNAPL effective solubility
DNAPL presence indicated by visual observation or hydrophobia dye testing of soil
+ Other ground-water sampling locations
Superfund Document Management System Used in Columbia Space Shuttle Recovery
On February 1, 2003, the STS-107 space
shuttle Columbia, traveling over 200,000 feet
in altitude, broke apart over central Texas
and eastern Louisiana. Response to the
accident was shared by the U.S. Federal
Emergency Management Agency (FEMA),
the National Aeronautics and Space
Administration (NASA), and EPA, which was
given authority to run field recovery
operations. EPAs Region 6 coordinated the
effort, using in large part the Superfund
Document Management System (SDMS)
already employed by headquarters and
regional offices.
Field work immediately began with four-
member crews walking at ami's length to
survey the ground for any material related
to the crash. Vegetation at that time of year
was relatively bare, but eastern Texas pine
[continued on page 5]
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[continued from page 4]
forests and western Louisiana swamps and
lakes complicated the task. As spring
approached, increasing vegetation,
venomous snakes, insects, and wild havilina
hogs added additional problems during the
search and recovery work. Over 10,000
volunteers representing or supplementing more
than 90 organizations, including EPA, the Texas
Forest Service, and the U.S. Forest Sendee,
joined the task of canvassing a debris field the
size of West Virginia.
Each search team carried into the field a hand-
held personal digital assistant (PDA) computer
with pre-loaded data forms, a digital camera,
and a geographic information system (GIS)
transponder. When anything appearing to be
related to the shuttle was found, the GIS position
was documented on a PDA form. Digital
photographs of the item were taken and other
descriptive data were noted in the PDA.
Precautions were taken with each item of
evidence. Worker protection was a concern due
to the presence ofhydrazine, a highly toxic rocket
propellant coating much of the debris. Each item
or container was affixed an identification tag
and transferred to a collection facility where
NASAand the Federal Aviation Administration
worked to reconstruct a layout of the shuttle.
Each evening as the search crews returned to
one of five established field stations, the
PDAs were placed in a bank of cradles and
linked to a set of GIS servers. PDA data were
transferred to an existing emergency-response
computer application that was up-scaled to
collate the large volume of information coming
from the field. Debris points were plotted onto
maps of the search areas and used by EPAs
on-scene coordinators to plan the next day's
search activities.
Region 6 information management personnel
worked with emergency response staff to
develop methods for documenting the diverse
data produced in the field. Within one week of
the accident, a commercially -developed mobile
unit prototype called "SUREAIM" was
delivered to a Lufkin, TX, command post to
capture records. Contractors trained in its use
and in Region 6 electronic records operations
also arrived within days. In order to use minimal
amounts of paper documentation, SUREAIM
employed a paper scanning component, a high-
speed workstation, and remote access software
(AAA virtual private network extranet tokens
under pilot in Region 6).
SURE AIM records typically were converted in
the field to Adobe PDF files and transferred daily
through the Agency firewall to a Region 6
automated Domino workflow tool called
"ExpressLink." Key metadata were assigned to
forms and associated documents and saved in
ExpressLink, which triggered placement of the
information in the SDMS.
Two years earlier Region 6 had re-engineered
the client-server SDMS into a fully web-based
form known as SDMS2 in order to receive
electronic records and to provide a more textured
information management environment for
Superfund staff, records managers, and support
contractors. The major procedural innovation
made possible by SDMS2, in tandem with the
PDA forms, was to move records management
from a relatively passive "receipt of records"
mode to one in which remediation staff was
involved in the early lifecycle of data. This
allowed record providers to immediately transmit
items to the records program, while retaining
unlimited access, and provided multiple parties
joint and simultaneous record access.
During the high-pressure shuttle recovery, the
ability of field staff to drop records off at the
SUREAIM station with knowledge that the
information would be rapidly processed and
available for on-demand access was a great
benefit. EPA currently is considering creation of
documentation teams that could perform the
same functions in emergency response centers
and field settings. GIS data management during
the recovery involved conversion of map layers
to scalable vector graphics and export of a
searchable database (with linked photos and
documents) into a new SDMS2 component.
Subsequent assessment of the field recovery
indicated that 99% of the documentation was
captured at or just after lifecycle creation. It also
was determined that field contractors had
successful access to site-specific information
and offsite discussions regularly. The effort
demonstrated that records can be transformed
from relatively restricted documentation of past
events into front-line decision-making tools.
EPA concluded its field operations in May 2003,
less than four months after the accident, with
significantly more of the spacecraft recovered
than expected. Within two weeks of closing
the field stations, full documentation of the
events was available in SDMS2 (with no paper
backlog), and a hard drive containing the
records was provided to NASA soon thereafter.
SDMS2 and other tools used for the shuttle
recovery have since emerged in Region 6 as
instruments applicable to more routine field
operations. With more than 50 million pages of
national Superfund records, management of
SDMS2 was transferred to EPA headquarters
early this year.
Contributed by Steven Wyman, EPA/Office of
Superfund Remediation and Technology
Innovation (and formerly of Region 6
(703-603-8882 or wyman.steve@epa.gov)
Contact Us
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welcomes readers' comments
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and Technology Innovation
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Phone:703-603-7199
Fax:703-603-9135
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Technology
News and Trends
Solid Waste and
Emergency Response
(5102G)
EPA 542-N-04-005
September 2004
Issue No. 14
United States
Environmental Protection Agency
National Service Center for Environmental Publications
P.O. Box 42419
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EPA/ORD/NRMRL Publishes Study on MNA Performance
L
EPA's ORD/National Risk Management
Research Laboratory' (NRMRL) recently
completed a study on the performance
monitoring of remedies that rely on natural
attenuation of contaminants. The study's
results are now available in the April 2004
report entitled Performance Monitoring of
MNA Remedies for VOCs in Ground Water.
As part of this effort, NRMRL developed
technical recommendations regarding the
types of monitoring parameters and
analyses that are useful for evaluating
monitored natural attenuation (MNA)
during the design and implementation of
MNA plans. NRMRL found that effective
monitoring system designs need to be based
on a thorough understanding of the
migration and ultimate fate of contaminants
in site-specific environments.
The study found that an effective monitoring
program includes routine evaluations of
institutional controls and measurements of
contaminant, geochemical, and hydrologic
parameters. These data are used to evaluate
changes in three-dimensional plume
boundaries, contaminant mass and
concentration, and hydrological and
geochemical changes that may indicate
changes in remedy performance.
Continuation of an MNA program is
appropriate when contaminant concentrations
behave according to remedial expectations,
and ground-water flow and geochemical
parameters remain within acceptable ranges.
Program modifications may include increases
or decreases in monitoring parameters,
frequency, or locations to reflect changing
conditions or an improved understanding
of natural attenuation processes at a site.
Implementation of a contingency or
alternative remedy may be triggered by:
> Increasing contaminant concentrations
or unexpected trends;
> Contaminant migration beyond the
established plume or compliance
boundaries;
> Insufficient rates of contaminant reduc-
tions;
> Land or ground-water use changes with
the potential to reduce protectiveness
of the remedy; or
> Unacceptable risks to receptors.
The complete publication (EPA 600/R-04/
027) is available online from CLU-IN at
http://www.cluin.org/publ .cfm.
J
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques and
technologies. The Agency does not endorse specific technology vendors.
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