United States
Environmental Protection
Agency
Solid Waste
Emergency Response
(5102G)
EPA 542-N-97-002
April 1997
Issue No. 24
4?EPA Ground Water Currents
Developments in innovative ground water treatment
TECHNOLOGY
Optimizing Hit Spaiging Systems
by Harley Hopkins, API
The American Petroleum Institute (API) is
currently funding a multi-university team to
evaluate a suite of tracer tests that may
provide more definitive real-time informa-
tion on the performance of an air sparging
system. API represents over 3 50 companies
involved in oil and gas exploration,
production, transportation, refining, and
marketing. API's Soil and Ground Water
Technical Task Force has been researching
innovative in situ approaches to remediate
soil and ground water for over 10 years.
Air sparging is being applied at a large
number of sites with petroleum-contami-
nated ground water. The new tests may
offer a way to evaluate air sparging system
performance with fewer trial-and-error
adjustments to air flow rates and sparge well
placement, and provide clearer data than
conventional techniques, such as monitoring
dissolved oxygen. One test involves
injecting a multi-compound tracer into a
sparged aquifer. The tracer contains a
solution of compounds that varies in
volatility and biodegradability. After a
period of time, the solution is withdrawn,
and changes in compound concentration are
measured. These data are used in models to
estimate volatilization, oxygenation, and
biodegradation rates. Laboratory tests of the
tracers are nearing completion Future field
studies at federal and private sites will
evaluate the viability and practicality of the
tracer tests.
API also is studying natural attenuation,
which is being used as a remediation
technology at thousands of leaking
underground storage tank sites in the U.S.
Ground water at these sites is contaminated
with benzene, toluene, ethylebenzene, and
xylenes (BTEX). At new release sites,
where it is not possible to make direct
observations of BTEX mass or concentra-
tion reduction, ground-water samples can be
analyzed for geochemical indicators of
natural biodegradation. Sampling methods
include conventional purge and bail, no
purging, and micropurging.
Analytical methods are being studied for a
number of geochemical parameters,
including dissolved oxygen, nitrate, sulfate,
ferrous iron, methane, carbon dioxide,
alkalinity, oxidation reduction potential, pH,
conductance, and temperature. The methods
under study vary in accuracy, level of effort,
and cost. The best method for a given
application depends on project and site-
specific considerations, particularly the
specific manner in which data are to be used.
fiir Sparging Performance lests Studied
Containment Conference Held
Reactive Halls Demonstrated
Natural flttenuation Demonstrated
NHPL Demonstration Revieiu Planned
Conference Scheduled on fldvances in Innovative
Ground Water Remediation lechnologies
Fractured Rock Guidance Issued
API expects to publish two reports this spring
on measuring indicators of intrinsic
bioremediation One evaluates sampling and
analysis methods; the other describes
application, advantages, and disadvantages of
various sampling and analysis techniques.
For more information, contact Harley
Hopkins (API) at 202-682-8318 or e-mail
hopkins@api.org. A list and description of
API soil and ground-water reports can be
obtained on API's World Wide Web site at
www.api.org/cat.
Containment Conference Held
Participants in the February 1997 Interna-
tional Containment Technology Conference
and Exhibition in St. Petersburg, FL,
discussed new methods for ground-water
characterization and remediation. Success
has been found in combining remediation
systems, such as directional drilling
combined with jet grouting, and
geomembranes combined with drains or
continued on pg.2
About this Issue
This issue highlights
ongoing research and
demonstration projects.
These efforts focus on a
number of technologies
and methods, including
air sparging, reactive
walls, natural attenua-
tion, and use of
surfactants.
Recycled/Recyclable
Printed with Soy/Canola Ink on paper that
contains at least 50% recycled fiber
-------
DEMONSTRATIONS
I
Containment Conference
continued from pg. 1
soil- or cement-based barrier materials.
New applications of existing technologies,
such as hydraulic fracturing and multipoint
injection, also were discussed.
Technical papers presented on the use of
permeable reactive walls confirm that this
technology has moved from the demonstra-
tion stage of development to the field
application stage. In contrast, participants
recognized that evaluation of performance
assessment has not advanced significantly.
Opportunities for technology improvement
include developing effective methods for
determining in situ hydraulic conductivity of
barrier materials, enhancing quality assur-
ance/quality control practices, developing
techniques for sealing vertical barriers into
aquicludes, and improving diffusion of
organics through geomembranes. Partici-
pants also discussed the need for increased
collection of performance data. Overall
preference for risk-based corrective action
was recognized as a significant factor in the
continued selection of innovative methods
of containment as a viable remediation
technology.
Conference proceedings will be available
in the late summer from Florida State
University's Conference Coordinator
at 904-644-5524 or e-mail
ICTCE@mailer.fsu.edu.
Reactive Nolls Demonstrated
by Richard Muza, EPA Region 8
Solvents are common contaminants in
ground water at many Superfund sites and
are particularly prevalent in ground water at
military facilities. To demonstrate the
applicability of iron reactive walls for
ground-water remediation at U.S. Air Force
facilities nation-wide, a zero-valent iron
reactive wall was installed at Lowry Air
Force Base, CO. The technology involves
use of a subsurface wall of iron filings
through which the contaminant plume
migrates under natural ground-water flow.
Chlorinated organics are degraded in situ
through a reductive dechlorination reaction
involving the zero-valent iron.
At Lowry, trichloroethylene was detected in
alluvial ground water at a maximum
concentration of 1,260 ppb, with related
chlorinated organics present at lower
concentrations. Monitoring results indicated
that all of the chlorinated species degraded
rapidly within the wall to concentrations
below their detection limits, resulting in the
formation of ethene, ethane, and methane.
Field degradation rates for the major
chlorinated organics were determined from
the performance monitoring data and
compared well to the results of other field
demonstrations of this technology. Monitor-
ing results indicated that changes with
distance within the wall were consistent with
the laboratory treatability study and other
in situ reactive wall installations.
Anion-cation distributions in ground water
were used to estimate theoretical porosity
losses in the reactive wall due to carbonate
and hydroxide precipitate formation.
Results showed an estimated potential
porosity loss of 13 to 14 percent per year.
Cost comparisons of the reactive wall verses
air sparging and pump-and-treat indicated
that a reactive wall becomes the most cost-
effective remedy after five to eight years.
The U.S. Air Force Center for Environmen-
tal Excellence, Colorado Department of
Public Health and Environment, and EPA
jointly concluded that the demonstration
was highly successful. For more informa-
tion, contact Richard Muza (EPA Region 8)
at 303-312-6595.
Natural Httenuation Demonstrated
A recent demonstration at the Ohio River
Park Site onNevelle Island, PA, indicates
that natural attenuation, coupled with source
capping, should prevent migration of
hazardous substances resulting from coke
waste product disposed in on-site trenches.
Ground water at the demonstration site is
drawn from the same aquifer used by a
municipal well field for the nearby town of
Coraopolis's drinking water. The contami-
nant plume has been determined to flow as
close as 1,000 feet from the well field.
Performance conclusions were based on the
existing distribution of benzene and 2,4,6-
trichlorophenol within the plume, which also
contains natural attenuation metabolic by-
products, including elevated concentrations
of methane, iron fl, and manganese fl. A
site-specific fate and transport model, which
was independently verified by EPA models,
predicts the effectiveness of natural attenua-
tion at this location. Extensive research is
underway to determine the location of three
or more long-term monitoring wells, and
additional data will be collected to confirm
and ensure effectiveness of the process. This
demonstration represents one of the first
applications of natural attenuation on plumes
associated with coal tar waste. For more
detailed information, contact Romuald A.
Roman (EPARegion 3) at 215-566-3212.
Eighth Annual Western Governors Association/Weapons Complex Monitor Applied Research and Cleanup Technology Colloquium;
Weapons Complex Waste Management and Cleanup: A "Corporate" Appraisal of the Investment in Cleanup Technology; April 29-
May 2, 1997; Radisson Executive Conference Center, Scottsdale, AZ; 847-234-2353 or e-mail excpub@jaol.com.
DOE"s Environmental Cleanup: New Ways of Doing Business; Sponsored by McGraw-Hill Companies Inside Energy; May 12-13,
1997; Hyatt-Regency, Washington, D.C.; 800-223-6180or 212-512-6410.
Air and Waste Management Association's 90th Annual Meeting & Exhibition; Science and Technology: the International Language;
June 8-13, 1997; Metro Toronto Convention Centre, Toronto, Canada; 412-232-3444ore-mailkfau@awma.org.
Emerging Technologies in Hazardous Waste Management (Enviro Expo 97); Sponsored by the American Chemical Society, Division
of Industrial and Engineering Chemistry; September 15-17, 1997; Pittsburgh Hilton and Towers, Pittsburgh, PA; 404-894-2856, e-
mail daniel. tedder@che.gatech. edu, or Internet http://www. chemse.gatech. edu/~iec/Enviro.html.
Annual Meeting of the American Society of Chemical Engineers; November 16-21, 1997; Westin Bonaventure and Omni Los Angeles,
Los Angeles, CA; 800-AIChemE, e-mailxpress@aiche.org, or World Wide Web at http://www Lche.ufl.edu/meeting/1997/annual/.
-------
I
Technology Practices Manual To Be Released
The first edition of an innovative technology practices manual for surfactants and co-solvents will be released this
month. Rice University, which has conducted extensive research on surfactants, is preparing the manual under a grant
from the Advanced Applied Technology Demonstration Facility at the U.S. Department of Defense. For more informa-
tion, contact Donald F. Lowe, Ph.D. (Rice University) at 713-527-4725.
DNAPL Remediation Report Issued
Researchers at the University of Oklahoma studied the inefficiency of conventional pump-and-treat methods for remov-
ing dense nonaqueous phase liquids (DNAPLs) and identified surfactants as a promising technology. Researchers also
examined regulatory approval and economics, which are considered the primary obstacles to widespread implementation
of surfactant-enhanced subsurface remediation. Results of their studies are described in the environmental research
brief, Surfactant-Enhanced DNAPL Remediation: Surfactant Selection, Hydraulic Efficiency, and Economic Factors
(EPA/600/S-96/002). To order, contact EPA's Robert S. Kerr Environmental Research Center at 405-436-8651.
NHPL Demonstration Review Planned
Major stakeholders in the field of surfactant-
enhanced remediation will meet May 7-8 at
Hill Air Force Base, UT, to review current
and planned in situ flushing activities. The
performance of recent demonstrations
suggests that removal of nonaqueous phase
liquids (NAPLs) is possible through in situ
flushing. Additional information may be
obtained from A. Lynn Wood (EPA National
Risk Management Research Laboratory) at
405-436-8552 or Steven Shoemaker
(DuPont) at 281-586-2513.
Conference Scheduled on
Hdvonces in Innovative Ground
Wafer Remediation Technologies
The Ground Water Remediation Technolo-
gies Analysis Center (GWRTAC), with
support from the EPA's Technology
Innovation Office, is sponsoring the
"Advances in Innovative Groundwater
Remediation Technologies Conference."
The conference will be held on July 31,
1997, in Philadelphia, PA, at the Warwick
Hotel. The conference will focus on recent
developments in, and a range of, innovative
in situ ground-water remediation technolo-
gies that are being developed and applied
throughout the U. S.
There is no registration fee; however,
advance registration is required. The
conference is open to ground-water
remediation professionals from the govern-
ment, research and development, university,
and consulting/remediation sectors. For
additional information, contact GWRTAC
at either (800) 373-1973, e-mail
gwrtac@netac.org, or visit the World Wide
Web site at http://www.gwrtac.org.
Regulators Review
Surfactant Injection
Interviews with eight state regulatory
authorities were conducted to document
their experiences with reviewing
applications or proposals to inject
surfactants into contaminated ground
water. The interviews include
discussions of barriers to application
acceptance and mistakes applicants
made in filing applications. The
resulting report, Surfactant Injection
for Ground-Water Remediation: State
Regulators Perspectives and
Experiences (EPA 542-R-95-011),
may be downloaded from the Clean-Up
Information (CLU-IN) site on the World
Wide Web (http://clu-in.com).
Fractured Rock Guidance Issued
A field site was developed and studied in the
Sierra Nevada, CA, foothills to test a multi-
disciplinary approach to the characterization
of ground-water flow and transport in
fractured rocks. The study was conducted at
the Raymond Field Site, which is operated by
the U.S. Department of Energy's Lawrence
Berkeley National Laboratory and the U.S.
Geological Survey. Project sponsors also
included Atomic Energy of Canada, Ltd.,
and U.S. EPA. Key findings of the project
are described in a project summary,
"Hydrogeologic Characterization of
Fractured Rock Formations: A Guide for
Groundwater Remediators" (EPA/600/S-96/
001) published by EPA's National Risk
Management Research Laboratory
(NRMRL). The project summary is available
from NRMRL at 405-436-8651. The U.S.
Department of Energy (DOE) has prepared
the companion project report,
"Hydrogeologic Characterization of
Fractured Rock Formations: A Guide for
Groundwater Remediators" (DOE report
number LBL-38142/UC-800), that compares
tools and methodologies for characterizing
ground-water movement in fractured rocks
and provides suggestions for analyzing and
integrating relevant data. Contact the
National Technical Information Service
(NTIS) at 800-553-6847 to obtain copies of
the complete project report (NTIS order
number DE96009137).
-------
I
Ground Water Currents is on the NET!
View or download it from CLU-IN at:
WWW site:
ftp site:
telnet to BBS:
http://clu-in.com
ftp://clu-in.com
telnet: //clu-in. epa.gov
(or 134.67.99.13)
Ground Water Currents welcomes readers'
comments and contributions.
Address correspondence to:
Ground Water Currents.,
8601 Georgia Avenue, Suite 500,
Silver Spring, Maryland 20910.
We now offer a new service-TechDirect-to keep you abreast of
new EPA publications and events of interest to site remediation
and site characterization professionals. Once a month, a
TechDirect message will be sent via e-mail describing new
products and instructions on how to obtain them.
To subscribe:
• Send an e-mail message to "listserver@unixmail.rtpnc.epa.gov"
• Please do not include a subject line in your message; you may
add a period "." if your mailserver requires an entry.
• The body of your message should say: subscribe techdirect
firstname lastname
• TIP: Please have your Postmaster exclude
"techdirect@unixmail.rtpnc.epa.gov" from your
AutoResponder if you are using one.
WE ARE TRYING TO SAVE TREES AND POSTAGE!
If you still wish to receive a printed copy of Ground Water Currents,
YOU MUST COMPLETE AND RETURN THE INFORMATION BELOW.
Fax it to the National Center for Environmental Publications and Information (NCEPI) at 513-489-8695, or mail the
form to NCEPI, P.O. Box 42419, Cincinnati, OH 45242-2419.
Name:
Agency/Company:
Street Address (include mail code):
City:
State:
Zip Code:
United States
Environmental Protection
Agency
Solid Waste
Emergency Response
(5102G)
EPA 542-N-96-002
April 1997
Issue No. 24
Qround Water Currants
Developments in innovative ground water treatment
------- |