COMMITTEE ON EPA 542-R-02-002
THE CHALLENGES OF March 2002
MODERN SOCIETY www.epa.gov/tio
www.clu-in.org
www.nato.int/ccms
NATO/CCMS Pilot Study
Evaluation of Demonstrated and
Emerging Technologies for the
Treatment of Contaminated Land
and Groundwater (Phase III)
2001
SPECIAL SESSION
Performance Verification of In Situ
Remediation Technologies
Number 251
NORTH ATLANTIC TREATY ORGANIZATION
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NATO/CCMS Pilot Study
Evaluation of Demonstrated and Emerging
Technologies for the Treatment of Contaminated
Land and Groundwater (Phase III)
2001
SPECIAL SESSION
Performance Verification of In Situ
Remediation Technologies
Liege, Belgium
September 10-14, 2001
March 2002
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NOTICE
This Special Session Report was prepared under the auspices of the North Atlantic
Treaty Organization's Committee on the Challenges of Modern Society
(NATO/CCMS) as a service to the technical community by the United States
Environmental Protection Agency (U.S. EPA). The report was funded by U.S. EPA's
Technology Innovation Office. The report was produced by Environmental
Management Support, Inc., of Silver Spring, Maryland, under U.S. EPA contract
68-W-00-084. Mention of trade names or specific applications does not imply
endorsement or acceptance by U.S. EPA.
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CONTENTS
INTRODUCTION 1
EXECUTIVE SUMMARY 3
PRESENTATIONS AT THE SPECIAL SESSION 5
1. Introduction to the Topic and the Special Session
Bert Satijn 6
2. Verification of In Situ Remediation Performance: Process Features and Challenges
Robert L. Siegrist 9
3. Needs, Views, and Concerns of the Regulators
Victor Dries 20
4. Needs, Views, and Concerns of the Site Owners
Terry Walden 26
5. Needs, Views, and Concerns of the Insurance Companies
Dominique Ranson 31
6. Site-Specific Verification of Soil Vapor Extraction
Michael Altenbockum and Oliver Kraft 47
7. Site-Specific Verification of Surfactant-Cosolvent Flushing
Leland Vane and S. Laura Yeh 59
8. Site-Specific Verification of In Situ Bioremediation
Frank Volkering 79
9. Site-Specific Verification of In Situ Chemical Oxidation
Eric Hood, Robert L. Siegrist and Neil Thomson 90
10. Site-Specific Verification of In Situ Permeable Reactive Barriers
VolkerBirke 99
11. Site-Specific Verification of In Situ Remediation of DNAPLs
Arun Galvaskar 104
12. Future Developments in Verification of In Situ Performance: Expectations, Instruments,
and Goals
Bert Satrjn 119
COUNTRY REPRESENTATIVES 125
ATTENDEES LIST 128
PILOT STUDY MISSION 135
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
INTRODUCTION
The Council of the North Atlantic Treaty Organization (NATO) established the Committee on the
Challenges of Modern Society (CCMS) in 1969. CCMS was charged with developing meaningful
programs to share information among countries on environmental and societal issues that complement
other international endeavors and to provide leadership in solving specific problems of the human
environment. A fundamental precept of CCMS involves the transfer of technological and scientific
solutions among nations with similar environmental challenges.
The management of contaminated land and groundwater is a universal problem among industrialized
countries, requiring the use of existing, emerging, innovative, and cost-effective technologies. This
document reports on the fourth meeting of the Phase III Pilot Study on the Evaluation of Demonstrated
and Emerging Technologies for the Treatment and Clean Up of Contaminated Land and Groundwater.
The United States is the lead country for the Pilot Study, and Germany and The Netherlands are the Co-
Pilot countries. The first phase was successfully concluded in 1991, and the results were published in
three volumes. The second phase, which expanded to include newly emerging technologies, was
concluded in 1997; final reports documenting 52 completed projects and the participation of 14 countries
were published in June 1998. Through these pilot studies, critical technical information was made
available to participating countries and the world community.
The Phase III study focuses on the technologies for treating contaminated land and groundwater. This
Phase is addressing issues of sustainability, environmental merit, and cost-effectiveness, in addition to
continued emphasis on emerging remediation technologies. The objectives of the study are to critically
evaluate technologies, promote the appropriate use of technologies, use information technology systems
to disseminate the products, and to foster innovative thinking in the area of contaminated land. The Phase
III Mission Statement is provided at the end of this report.
The Phase III pilot study meetings were hosted by several countries and at each meeting, a special session
was held for the discussion of a specific technical topic. The meeting dates and locations were:
• February 23-27, 1998: Vienna, Austria
• May 9-14, 1999: Angers, France
• June 26-30, 2000: Wiesbaden, Germany
• September 9-14, 2001: Liege, Belgium
The special session topics were:
• Treatment walls and permeable reactive barriers (Vienna)
• Monitored natural attenuation (Angers)
• Decision support tools (Wiesbaden)
• Validation of in situ remediation performance (Liege)
This and many of the Pilot Study reports are available online at http://www.nato.int/ccms/ and
http://www.clu-in.org/intup.htm. General information on the NATO/CCMS Pilot Study may be obtained
from the country representatives listed at the end of the report. Further information on the presentations in
this special session report should be obtained from the individual authors.
Stephen C. James
Walter W. Kovalick, Jr., Ph.D.
Co-Directors
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
EXECUTIVE SUMMARY
Robert L. Siegrist1 and Bert Satijn2
Subsurface contamination by toxic chemicals, including natural and synthetic organic compounds and
heavy metals, is a widespread problem at industrial and military sites around the world. At many
contaminated sites, there is a sufficiently serious current or future risk to public health and environmental
quality such that remediation is warranted. To eliminate a current or future risk, remediation approaches
increasingly employ in situ technologies comprised of engineered as well as natural attenuation systems.
In situ remediation in source areas of contaminated soil and groundwater can be accomplished using mass
transfer and recovery methods such as soil vapor extraction, air sparging, and surfactant/cosolvent
flushing. In destruction methods can also be employed such as bioremediation and chemical
oxidation/reduction. These source area treatment methods can sometimes be enabled by techniques such
as soil mixing, soil fracturing, and soil heating. Ground water plumes can be treated by some of these
methods as well as through natural biogeochemical attenuation. Finally, for the control of the leading
edge of ground water plumes, treatment walls and permeable reactive barriers can be applied.
As site cleanup goals are established (whether it be by a quantitative risk assessment or another method),
one must delineate the current nature and extent of contamination in the subsurface and also the desired
end-state after in situ treatment has been completed (e.g., risk-based concentrations throughout a volume
of soil). Then, the needed technology performance with respect to the contaminant concentration, mass,
mobility or toxicity must often be prescribed to achieve the risk reduction judged necessary. Verifying
(or validating) potential performance capabilities can be based on process theory, research, and full-scale
implementation and nationally standardized test programs (e.g., U.S. EPA Superfund Innovative
Technology Evaluation (SITE) program). Verifying actual performance achieved at a specific
contaminated site is necessarily based on measurements made at that site to quantify treatment effects that
result in changes in contaminant concentration, mass, mobility, and/or toxicity as well as environmental
conditions indicative that the desired treatment is occurring.
Verifying that the treatment performance goals set for an in situ remediation technology have been
achieved at a specific site is very challenging due to several factors. In general, the effective verification
of in situ performance at a particular site becomes more and more challenging with: increasing site size
and heterogeneity, presence of dense nonaqueous phase liquids (DNAPLs), cleanup goals that involve
high mass removals of contaminants or very low levels of residual contaminants, and remediation
technologies that require long time frames and don't readily permit mass balances.
In this Special Session of the NATO/CCMS Pilot Study on the Evaluation of Demonstrated and Emerging
Technologies for the Treatment and Cleanup of Contaminated Land and Groundwater (Phase III), was
focused on "Validation of Performance of In Situ Remediation Technologies." During this 1.5-day
session, there were 14 presentations made. The initial afternoon of the session was devoted to an
introduction to the topic (Bert Satijn, The Netherlands) and an overview of process features and
challenges (Bob Siegrist, USA). There were also presentations on the needs, views and concerns of the
regulators (Victor Dries, Belgium), the site owners (Terry Walden, UK), and the insurance companies
(Dominique Ranson, Belgium). The second day was focused on site-specific validation of several
technologies including soil vapor extraction (Michael Altenbockum and Oliver Kraft, Germany),
surfactant/cosolvent flushing (Leland Vane, USA), bioremediation (Frank Volkering, The Netherlands),
chemical oxidation (Robert Siegrist, USA), and permeable reactive barriers (Volker Birke, Germany).
These presentations were followed by a presentation on the site-specific validation of in situ remediation
at sites with dense nonaqueous phase liquids (DNAPLs) (Arun Gavaskar, USA). The special session was
1 Professor and Division Director, Colorado School of Mines, Environmental Science and Engineering Division, Golden, CO. USA
80401-1887. Phone : 303.273.3490. Telefax: 303.273.3413. Email: siegrist@mines.edu.
2 SKB, Dutch Foundation for knowledge development and transfer on soil quality management. Buchnerweg 1, Gouda 2800, The
Netherlands. Phone: 31(0)182540690 Telefax: 31(0)182540691 Email: Bert.Satijn@CUR.nl
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
to end with a presentation on future developments including expectations, instruments, and goals, The
Netherlands) followed by an open discussion period. However, this period was not nearly as productive
as it might have been, as the news of the tragic terrorist attacks in the USA became known and attention
was refocused on the events of the day.
Based on the presentations made during the Special Session and the discussions that occurred during the
meeting, several concepts emerged with regard to validating in situ remediation performance. The co-
chairs of the Special Session (Siegrist and Satijn) captured the following concepts that appeared to be
recurring themes during the presentations and discussions:
• Verifying (or validating) potential performance capabilities is not the same as verifying actual
performance achieved.
• The right combination of several in situ techniques in place and time will often provide the best
solution. In this case the verification of the processes is even more challenging. It may also be
appropriate to combine in situ methods with ex-situ techniques in a proper way to achieve the most
cost efficient result.
• Engineers, regulators, site owners and others need to set realistic goals for in situ remediation and the
methods for verifying performance achieved at a particular site. We need to set realistic expectations,
which we can, deliver on and defend.
• Clean up of the 3-dimensional subsurface completely to a specific performance goal is challenging,
and it is unreasonable to expect that every cubic meter of treated soil will be at or below a target goal.
• Validation requires careful application of monitoring and measurement methods, and methods must
be applied to deal with uncertainty. Subsurface investigations that rely on soil sampling and analyses
are generally poor and need improvement. Existing, as well as new and more sophisticated,
techniques need to be integrated and used to provide multiple lines of evidence enabling conclusions
to be made regarding performance goal achievement.
• In situ remediation technologies should be designed and implemented at a particular site to enable
performance verification to be achieved.
This report includes the visuals used during the presentations made at the NATO/CCMS meeting in
Liege, Belgium on September 10-11, 2001. In most cases, these presentation materials have been
supplemented with an extended abstract or paper. Individuals who are interested in learning more on the
subject of an individual presentation or on the Special Session should feel free to contact the participants
at the address listed in the back of this report.
We would like to acknowledge the participants in this Special Session for their efforts in preparing
insightful presentations and contributing papers and presentation materials to this report. We are also
grateful to the input and support received from Steve James, Walter Kovalick, Volker Francius, and John
Moerlins.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
PRESENTATIONS AT THE SPECIAL SESSION
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
INTRODUCTION TO THE TOPIC AND THE SPECIAL SESSION
Bert Satijn1
1. INTRODUCTION
Validation of in situ remediation techniques is the topic for this NATO/CCMS Special Session. Before
going into the technical aspects, it is necessary to agree on the definition of the word "validation", which
in this Special Session, may be used interchangeably with "verification". Validation (or verification)
could be defined as a protocolized method to determine the performance of a remediation technology,
applying quantitative criteria. So in simple words: to prove that is it working.
In many projects the validation of the performance of a remediation system starts at the end of the
remediation technique, but in fact it should start with the soil investigation and the design of the
remediation system. Important questions are:
1. Do I have a complete view on:
a. the site-specific conditions of soil, groundwater, contaminations, subsoil processes of migration
and attenuation;
b. function (present and future);
c. risk profiles of the site;
d. the boundary conditions for a clean-up;
e. and especially the goal for remediation (preferably in semi-quantitative criteria).
2. What system of remediation could be successful and cost effective? Normally we are thinking of
applying one technique, but it often becomes clearer that the right combination of techniques, depth
and time-dependent, provides most probably the most cost-efficient solution. A combination of in-situ
processes creates an extra challenge for the validation.
3. How will the exploitation of the remediation system be organized? Which steering parameters will be
measured and how will they be used?
So the validation process is the last in a chain of activities and depending very much on the first steps.
Before going into the discussion on validation, first some statements on the in-situ techniques will be
made.
2. STATE OF THE ART OF IN SITU TECHNOLOGIES
In-situ techniques for remediation are relatively new. In the U.S., Germany, the Netherlands and some
other countries, our experience is not more than ten years. It started with the pump and treat systems that
became in many cases pump & spill. The reason for this was that we didn't understand the relation
between diffusion and advection processes, and determining the effectiveness of cleanup by pumping
alone.
The goals for in situ techniques are not always realistic, as they can be set by an opportunistic consultant.
Subsoil processes in biogeochemistry are not well understood. The complexity of processes in
biogeochemistry is high and not easy to monitor. The depth, the simple monitoring devices, and related
costs are important factors that explain why there is always a lack of enough data, both in space and time.
Heterogeneity is our challenge, on the mm-, cm- and m-scale. Results of the monitoring system are
seldom smoothly declining graphs. Uncertainties about the effect of remediation activities are stuff for
long discussions between the stakeholders. Soil is heterogeneous while legislation and criteria do not
know how to deal with uncertainties and fluctuating results. There is a big gap between policy and
8KB, Dutch Foundation for knowledge development and transfer on soil quality management. Buchnerweg 1, Gouda 2800, The Netherlands.
Phone: 31(0)182540690 Telefax: 31(0)182540691 Email: Bert.Satijn(g).CUR.nl
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
legislation on the one hand and the practical possibilities on the other hand. Lack of long term monitoring
results and thorough evaluations of in-situ techniques can hinder good performance testing and validation
of these techniques.
3. VALIDATION OF IN SITU TECHNOLOGIES
The question at hand is, "How to prove that the in-situ technique is working?" There are several methods
and approaches that, in combination, can provide information on the performance of an in situ technology
at a specific site and support its validation:
• Reduction of concentrations, macroparameters and microparameters;
• Change of process conditions, redox, temperature, EC, etc.;
• Mass flux reduction;
• Restoration of ecosystem (e.g., nematodes);
• Isotope analyses and other specific analyses; and
• Risk reduction
In the technical sessions various approaches for validation and performance testing will be presented. But
the following statements could be made as key issues for this special session:
• Subsoil processes in biogeochemistry have to be studied in more detail:
o Macro-parameters versus micro-parameters;
o Primary processes versus secondary processes;
o Optimization of combination of physical, chemical and biochemical processes.
• Thorough evaluations and verification programs including proper validation do have to provide the
performance indicators and bottlenecks;
• Development of monitoring devices has to lead to technologies and methods that provide more, better
and cheaper data; and
• The needs and criteria of regulators and site owners have to be translated into validation and
verification concepts that deal with field heterogeneity, but nevertheless fit into legislation and
performance criteria.
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Performance Verification of In Situ Remediation
4. PRESENTATION VISUALS -presented by Bert Satijn
NATO/CCMS Pilot Project Phase III
NATO/CCMS Special Session
Validation of hi Situ
Remediation Performance
he session
Introduction of the session
Validation of in situ techniques:
-^to prove that is it working
State of the An of in sini techniques
— Relatively new technology
- Complex processes '" biogcochcinislry
Introduction of the session (2)
I low to prove that the in situ
technique is working
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• Mass flux reduction
* Itisk reduction
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Program Monday Afternoon
(3:30 — 1.1:45 Introduction to (he session
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
VERIFICATION OF IN SITU REMEDIATION PERFORMANCE:
PROCESS FEATURES AND CHALLENGES
Robert L. Siegrist1
1. CONTAMINATED SITES AND RISK MANAGEMENT
Subsurface contamination by toxic chemicals is a widespread problem in soil and ground water at
industrial and military sites in the U.S. and around the world (NRC 1994, NRC 1997, USEPA 1997,
Visser 1993, CARACAS 1998, NATO 1999a). Organic chemicals are often the primary contaminants of
concern (COCs) and they commonly include volatile organic chemicals (VOCs) such as
tetrachloroethene, trichloroethene, and benzene, and semivolatile organic chemicals (SVOCs) such as
polyaromatic hydrocarbons and pesticides (Riley et al. 1992, Siegrist and Van Ee 1994, ATSDR 1999,
USEPA 1997). In addition, there may be metals (e.g., Pb, Cr) and radionuclides (U, Tc) as co-
contaminants of concern (Evanko and Dzombak 1997).
In the beginning, when contaminated sites were first discovered and their potential impacts on human
health and environmental quality were first revealed, appreciable levels of hazardous chemicals in
uncontrolled environmental settings (e.g., soil or groundwater) were presumed to present a condition in
need of action and implicitly, an unacceptable risk. Risk reduction was typically achieved by excavation
of soil and waste with subsequent treatment and disposal offsite, combined with pump and treatment of
contaminated groundwater (Mackay and Cherry 1989, USEPA 1997, USEPA 1999). Now more explicit
risk assessment and management underpins cleanup programs for Superfund and most other contaminated
sites (USEPA 1989, Labieniec et al. 1996, Sheldon et al. 1997, CARACAS 1998). Baseline risk
assessments are first completed to define the need for and extent of site cleanup and to develop site
specific remediation alternatives to mitigate unacceptable risks to an agreed upon goal. Generic, rather
than site-specific, risk assessments can also be done to develop screening level criteria for assessing sites
and establishing cleanup goals (e.g., Visser 1993, USEPA 1996).
Varied exposure scenarios can present serious current or future risks at many contaminated sites. At
many sites, risk is often governed by human exposures to chemicals in drinking water. Such
contamination has commonly resulted from wastes released at or near the land surface and the subsequent
migration of chemicals through soil into the underlying ground water (Figure 1).
To mitigate current or future risks, remediation approaches increasingly employ in situ technologies
comprised of engineered as well as natural attenuation systems (Figure 2) (NRC 1994, NRC 1997,
USEPA 1997, NATO 1998, NATO 1999a,b, Siegrist et al. 2001). In situ remediation in source areas of
contaminated soil and groundwater is being accomplished using mass transfer and recovery methods
(e.g., soil vapor extraction, air sparging, surfactant/cosolvent flushing) and in place destruction methods
(e.g., bioremediation, oxidation/reduction), sometimes aided by enabling techniques (e.g., soil mixing or
fracturing, soil heating). For treatment of the distal regions of groundwater plumes, natural
biogeochemical attenuation and permeable reactive barriers are being employed.
1 Professor and Division Director, Colorado School of Mines, Environmental Science and Engineering Division, Golden, CO. USA
80401-1887. Ph. 303.273.3490. Fax. 303.273.3413. Email, siegrist@mines.edu.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Figure 1: Illustration of a common contaminated site scenario where land disposal of industrial wastes
has led to organic chemicals leaching into the subsurface being transported to receptors exposed by
ingestion of contaminated drinking water or inhalation of vapors.
Contaminant
source
Contaminant
transport
Groundwater zone
Receptors
w/exposures via
ingestion of
drinking water or
inhalation of
vapors
Water well
Figure 2: Remediation approaches for in situ application at atypical contaminated site such as illustrated
in Figure 1 (after Siegrist et al. 2001).
COCs
Source Zone
^ Free product '5
recovery
•/ Surfactant or
cosol vent
]
/
flushing
recovery
•S Steam
flushing
^^
recovery f \
Heating
enhanced
recovery
Chemical
oxidation
Core Zone of the Plume
^ Airsparging and
Soil vapor
extraction
•/ Engineered
oxidation
^ Chemical
reduction
Saturated zo ne
1
.
< — o
\ N S \
Groundwater table \
Distal Zone of the Plume
^ Monitored natural
attenuation
•/ Engineered
bioremediation
^ Chemical oxidation
•/ Chemical reduction
^ Permeable reactive
barriers
Groundwater flow and CO C flux to
potential receptors of concern
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
2. VERIFICATION OF PERFORMANCE POTENTIAL VS. SITE-SPECIFIC ACHIEVEMENT
Risk reduction can be achieved using in situ remediation technologies by treating the COCs and
decreasing their concentrations, mass, mobility and/or toxicity. Verification that risk has in fact been
reduced to a target level established using a site-specific risk assessment or application of screening-level
cleanup criteria is based on a quantitative assessment of technology performance. In its broadest sense,
technology performance encompasses more than just treatment efficiency and risk reduction. In general,
it may be defined as: "Performance is a measure of a technology application with respect to a specified
function". Example functions include:
• Treatment efficiency (and risk reduction),
• Ease of implementation,
• Degree of site disruption and aesthetic impact,
• Compatibility with long-term land use plans, and
• Cost effectiveness.
Technology performance with respect to treatment efficiency is of concern in this paper and NATO
special session. Treatment efficiency and risk reduction must necessarily be incorporated into
remediation practice, either implicitly or explicitly. As site cleanup goals are established (whether it be by
a quantitative risk assessment or another method), one must delineate the current nature and extent of
contamination in environmental media throughout some location in space and time and also the desired
end-state after treatment (e.g., risk-based concentrations throughout a volume of soil). Then, the needed
technology performance with respect to the contaminant concentration, mass, mobility or toxicity must be
prescribed to achieve the risk reduction judged necessary (e.g., treatment to reduce COC levels below
drinking water limits). Technology performance goals related to treatment are thus set such that
achieving them would enable overall site cleanup to be realized.
Verifying (or validating) potential performance capabilities is not the same as verifying actual
performance achieved. Potential performance capabilities can be established based on knowledge gained
from different methods and scales of realization (Figure 3). Performance potential is often initially
projected based on an initial treatment concept, along with process theory based on contaminant
properties and site characteristics. An example is the projection of potential performance of soil vapor
extraction to remove volatile organic compounds from unsaturated, permeable soils located above the
ground water table. Understanding and confidence in potential performance can be increased through
confirmatory testing and evaluation completed during laboratory testing and field pilot-scale
demonstrations as well as through full-scale implementation and nationally standardized test programs
(e.g., U.S. EPA Superfund Innovative Technology Evaluation (SITE) program). As technology
implementation occurs at a large number of sites, a standard of practice can emerge and continue
to evolve.
Verifying actual performance achieved at a specific contaminated site is necessarily based on
measurements made at that site to quantify treatment effects that result in reduced risk. Assessment of
technology performance related to risk reduction are often based on quantifying changes in contaminant
concentration, mass, mobility, and/or toxicity as well as environmental conditions indicative that the
desired treatment is occurring. Verifying that the treatment performance goals set for an in situ
remediation technology have been achieved at a specific site is very challenging due to several factors.
Contaminants often have complex and uncertain distributions among multiple phases (e.g., vapor,
aqueous, solid, and non-aqueous liquid) and over time and space in the subsurface. This results in great
difficulties to interpolate and accurately estimate values at unobserved locations. Verification of
performance achievement to reach stringent cleanup goals (e.g., the 5 ug/L U.S. drinking water standard
for trichloroethylene (TCE)) can be challenging due to the small range for error and uncertainty (i.e., 0 to
5 ug/L) in estimating that treatment has achieved the goal. Finally, some treatment technologies can
11
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
constrain the viability of performance verification methods due to their process function and treatment-
induced heterogeneities (e.g., inability to close a mass balance on COCs, development of preferential
pathways).
In general, the effective verification of in situ performance at a particular site becomes more and more
challenging with: (1) increasing site size and heterogeneity, (2) presence of dense nonaqueous phase
liquids (DNAPLs), (3) cleanup goals that involve high mass removals of contaminants or very low levels
of residual contaminants, and (4) remediation technologies that require long time frames and don't readily
permit mass balances.
Figure 3: Methods and scales of information gain during development of an understanding of the
potential performance capabilities of in situ remediation technologies.
Initial concept...
Well-to-well flush in
ZMnO,- + CjHCI, = ZMnOjIs) + 2CQ+ 3d- + H*
Process theory...
Based on COC properties,
reactions, and
transport/fate behavior:
Laboratory experiments...
Controlled conditions often at
cm- to m- and min.- to day-
scales
Field pilot-scale demonstration...
Semi-controlled conditions at 10-to
100-m and week- to month-scales
Full-scale implementation
and evaluation...
Uncontrolled field conditions
with applications at various
space and time scales
A standard of
practice emerges
and continues to
evolve...
3. APPROACHES TO SITE-SPECIFIC PERFORMANCE VERIFICATION
Verifying actual performance achieved at a specific contaminated site must often be accomplished by
quantifying, to some degree of certainty, changes in contaminant concentration, mass, mobility, and/or
toxicity as well as environmental conditions consistent with treatment process function. These approaches
are highlighted below.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
3.1 Quantifying Contaminant Concentrations
A common cleanup goal for contaminated ground water can be drinking water standards (e.g., 5 ug/L
TCE). At a specific site where this cleanup goal might be set for a nearby drinking water well, the
technology performance goal could be to decrease the concentrations of TCE to some target level in soil
and/or ground water within the contaminated site boundaries so that natural attenuation would yield a
concentration at or below drinking water standards at the nearby drinking water well. Performance
verification for this goal normally would involve sampling at multiple locations and times with analyses
for the COC of interest. The resulting dataset would then be subjected to statistical analysis to enable
comparison of post-treatment conditions to the goal of 5 ug/L TCE. Potential problems and challenges
with this type of goal and verification approach include (1) the need for large numbers of samples to
address site heterogeneities and temporal and spatial variability, (2) the potential for large measurement
errors with some COCs in some media (e.g., volatile organic compounds in soil), (3) the potential errors
in interpolation methods used to estimate levels at locations without measurements, and (4) the fact that
concentration changes may not be due to in situ treatment (e.g., changes could be due to rate-limited
processes and dilution effects during in situ flushing or extraction technologies). These problems and
challenges can be overcome, at least in part, by careful and integrated use of modern sampling and
analyses methods, field analytical methods, in situ sensor technologies, and geostatistical modeling
methods (Crumbling et al. 2001, NATO 2001).
3.2 Quantifying Contaminant Mass
Another type of cleanup goal is to decrease the mass of COCs to a target level within a specified region of
the subsurface such that the release rate for contaminants to soil gas or ground water is reduced to an
acceptable rate (often a rate that results in no further growth or even contraction of plumes with
concentrations in them being below a set value). To enable application of this type of goal, the COC
mass present before and after treatment must be determined and this is normally done by characterizing
contaminant concentrations and multiplying them by the volume of media and its density. The COC mass
reduction is then estimated by comparing the post-treatment mass to the pre-treatment mass. Verifying
that a specified mass reduction (e.g., 90%) has been achieved requires the same elements as required for
quantifying contaminant concentration changes (see Section 3.1). In addition, it requires knowledge of
the media volume and density. Potential problems and challenges with quantifying contaminant mass
include the same ones confronting quantification of contaminant concentrations, namely: (1) COCs can
be distributed in a complex manner among phases and in vertical and horizontal dimensions, (2) the
potential for large measurement errors with some COCs in some media (e.g., volatile organic compounds
in soil), (3) the potential errors in interpolation methods used to estimate levels at locations without
measurements, (4) the fact that concentration changes may not be due to in situ treatment, but also (5) the
added fact that in situ remediation can alter subsurface conditions and make comparison of post-treatment
masses invalid (e.g., treatment-induced mobilization of DNAPLs). As noted previously, these problems
and challenges can be overcome by careful and integrated use of modern sampling and analyses methods,
field analytical methods, in situ sensor technologies, and geostatistical modeling methods. In addition, at
sites contaminated by DNAPLs, diagnostic tools such as partitioning tracers represent a group of methods
that can interrogate the subsurface and potentially provide a more accurate estimate of contaminant mass
within a volume of the subsurface as compared to that provided by discrete samples and geostatistical
analyses. Other emerging methods that enable integrated assessment of subsurface regions include large-
scale pump tests and mass flux meter techniques.
3.3 Quantifying Contaminant Mobility
Quantifying contaminant mobility traditionally has been applied to characterize leachability of COCs
from solid media such as soil, sediments, debris, or waste products. This is normally done using various
laboratory leaching procedures such as the U.S. EPA toxicity characteristics leaching procedure (TCLP).
However, quantifying COC mobility can also be used to assess the risk reduction achieved by changes in
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concentrations in plumes emanating from source areas. For example, at sites contaminated by DNAPLs,
depending on the DNAPL properties and subsurface distribution along with the site heterogeneities and
ground water flow regime, reducing the initial DNAPL mass present by some amount (but not necessarily
100%) can reduce the mass flux from the DNAPL and thereby reduce the concentration in the ground
water plume to a specified goal. Many of the same problems and challenges that confront efforts to
quantify contaminant concentrations and mass also confront assessment of COC mobility. Likewise, the
same approaches to overcome limitations are also available.
Figure 4: Classic approach to quantifying COC concentrations by discrete sampling and analyses to
enable geostatistical modeling of COC concentration and mass distributions, and the basis for error and
uncertainty due to complex subsurface conditions and site heterogeneities.
3.4 Quantifying Contaminant Toxicity
Performance goals can be targeted at changing COC toxicity through treatment to some target level in soil
and/or ground water within some region of the subsurface. One example of such a goal is in situ
treatment to transform 100% of the chromium in soil from Cr+6 to the less toxic, Cr+3. In addition to the
problems and challenges associated with quantifying concentrations or mass in the subsurface, there can
be questions about verifying long-term stability of the observed toxicity reduction effect. This requires
long-term testing or sufficient fundamental understanding to predict long-term effects with certainty.
3.5 Supporting Measures
Measurements and observations of conditions that are indicative that in situ treatment is being
accomplished can also be used to aid verification of in situ remediation technology performance.
Examples of these types of supporting measures include: (1) remote sensing and geophysical mapping of
treatment agent (or effect) delivery into a subsurface zone to be remediated, (2) measurement of
biogeochemical conditions indicative of treatment process function (e.g., pH, Eh, dissolved oxygen,
microbial activity, matrix chemistry), and (3) measurement of reaction products (e.g., CO2 produced by
biodegradation of petroleum hydrocarbons or chloride ions produced by oxidative degradation of TCE).
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4. SUMMARY
In situ treatment technologies are increasingly being considered for remediation of contaminated sites, yet
questions remain regarding how one can effectively and reliably verify performance. Verification of
performance of in situ technologies and the achievement of cleanup goals at a specific site can be
extremely challenging for many reasons, most notably perhaps, due to the complex distributions of
contaminants in multiple phases over space and time in the subsurface and the difficulties to interpolate
and accurately estimate values at unobserved locations. Multiple types of data that demonstrate one or
more measures of treatment effectiveness (i.e., reduction in concentration, mass, mobility, and/or toxicity)
are normally needed to effectively verify treatment performance at a particular site. In acquiring these
data, careful application of multiple monitoring and measurement approaches and methodologies is
critical to ensure that the proper data are collected and sufficiently comprehensive and accurate for the
intended purpose. As one contemplates in situ remediation and the verification of performance at a
particular site, questions emerge such as:
"What are realistic expectations for verification of in situ performance? For example, is 95% mass
removal with 90% confidence a reasonable expectation?"
"What is the best verification approach for a given type of in situ remediation technology and site-
specific performance goal?"
"What is an appropriate level of investment in verification at a particular site? For example, is 5% of
total project cost appropriate? What about 15% or 30%?"
"Should the choice of an in situ technology for a specific site depend on the ability to effectively
verify performance at that site?"
As the practice of in situ remediation continues to evolve and field experiences are complemented by the
results of research and development efforts, answers to these and related questions will hopefully emerge.
5. REFERENCES
1. ATSDR (1999). Agency for Toxic Substances and Disease Registry (ATSDR). ToxFAQs.
http://www.atsdr.cdc.gov. April 1999
2. CARACAS (1998). Risk Assessment for Contaminated Sites in Europe. LQM Press, Land Quality
Management Ltd., Nottingham NG26FB, United Kingdom.
3. Crumbling, D.M., C. Groenjes, B. Lesnik, K. Lynch, J. Shockley, J. Van Ee, R. Howe, L. Keith, and
J. McKenna (2001). Managing uncertainty in environmental decisions. Env. Sci. & Technol, October
2001, p. 405A-409A.
4. Evanko, C.R. and D.A. Dzombak (1997). Remediation of metals-contaminated soils and
groundwater. Technology Evaluation Report, TE-97-01. Groundwater Remediation Technologies
Analysis Center, Pittsburgh, PA.
5. Labieniec, P.A., D.A. Dzombak, and R.L. Siegrist (1996). SoilRisk: A risk assessment model for
organic contaminants in soil. J. Environmental Engineering. 122(5): 388-398.
6. MacKay, D.M. and J.A. Cherry (1989). Groundwater contamination: limits of pump-and-treat
remediation. Environ. Sci. & Technol. 23: 630-636.
7. National Research Council (NRC) (1994). Alternatives for groundwater cleanup. National Academy
Press, Washington, D.C.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
8. National Research Council (NRC) (1997). Innovations in ground water and soil cleanup. National
Academy Press, Washington, B.C.
9. NATO (1998). Treatment walls and permeable reactive barriers. NATO/CCMS Pilot Study Special
Session, February 1998, Vienna. EPA/542/R-98/003. May 1998. www.nato.int.ccms.
10. NATO (1999a). Evaluation of demonstrated and emerging technologies for the treatment and clean
up of contaminated land and groundwater. Pilot study reports, 1985-1999. U.S. EPA 542-C-99-002.
11. NATO (1999b). Monitored natural attenuation. NATO/CCMS Pilot Study Special Session, May
1999, Angers, France. EPA/542/R-99/008. www.nato.int.ccms
12. NATO (2001). Decision Support Tools. Special Session report from the NATO/CCMS Country
Representatives Meeting on Evaluation of Demonstrated and Emerging Technologies for
Contaminated Land and Groundwater, June 26-30, 2000, Wiesbaden, Germany. EPA 542-R-01-002.
135 pgs.
13. Riley, R. G. and J. M. Zachara (1992). Nature of chemical contaminants on DOE lands.
DOE/ER-0547T. Office of Energy Research, U.S. Department of Energy, Washington, D.C.
14. Sheldon, A.B., H.E. Dawson, and R.L. Siegrist (1997). Performance and reliability of intermedia
transfer models used in human exposure assessment. In: Environmental Toxicology: Modeling and
Risk Assessment. ASTM STP 1317, Philadelphia, PA.
15. Siegrist, R.L. and J.J. van Ee (1994). Measuring and interpreting VOCs in soils: state of the art and
research needs. EPA/540/R-94/506. U.S. EPA ORD, Washington, D.C. 20460.
16. Siegrist, R.L., M.A. Urynowicz, O.R. West, M.L. Crimi, and K.S. Lowe (2001). Principles and
Practices of In Situ Chemical Oxidation using Permanganate. Battelle Press, Ohio. 336 pg.
17. USEPA(1989). Risk assessment guidance for Superfund, Volume I: Human health evaluation
manual (Part A). EPA/540/1-89/002. U.S. EPA, Washington, D.C.
18. USEPA(1996). Soil screening guidance: technical background document. EPA/540/R95/128. U.S.
EPA Office of Solid Waste and Emergency Response. Washington, D.C. May 1996.
19. USEPA (1997). Cleaning up the Nation's waste sites. Markets and technology trends. EPA 542-R-
96-005. Office of Solid Waste and Emergency Response. Washington, D.C.
20. USEPA (1999). Groundwater cleanup: overview of operating experience at 28 sites. EPA 542-R-99-
006. Office of Solid Waste and Emergency Response. Washington, D.C.
21. Visser, W.J.F. (1993). Contaminated land policies in some industrialized countries. Technical Soil
Protection Committee, the Hague, The Netherlands.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
6. PRESENTATION VISUALS ~ presented by Robert L. Siegrist
Validation of In Situ Remediation
Performance ~ An Overview
Robert L. Siegrist, Ph.D., P.E.
Professor and Director
Environmental Science & Engineering
Colorado School of Mines
Golden. CO 80401-1887
Telephone: 303.273.3480
Email: tilegHst@mlnes.edu
NA TO/CCMS Country Representatives Meeting
L/ege, Belgium
9-14 September 2001
Contaminated Sites
Simple to complex
Small to large
Low to high risk .....
Receptors
w/ exposures via
ingestion of
dfrnkrng water or
nhalation of
vapors
COCs
"...In situ rem&alatlon to reduce risk fiy
treating COCs and decreasing their mass,
concentrations, mobility, and/or taxfclly."
Opening Remarks I
Presentation scope
~i Contaminated sites and risk-based management
~l In situ remediation technologies
T Technology performance and goals
"1 Methods for validating performance goal
achievement for in situ technologies
Site location and proximity to receptors
Size and geometry of contaminated media
/ Small volumes of shallow contaminated soil
/ Large, deep groundwater plumes
Subsurface properties
•t Groundwater in sands vs. layered sediments vs. fractured rock
•/ Unsaturated sandy soil vs. low permeability media vs. fHI
Contaminant type and properties
/ Organics vs. metals; simple vs. complex mixtures
/ Contaminant volatility, solubility, and reactivity
Contaminant distribution in the subsurface
J Distribution among phases (NAPL, sorbed, aqueous, vapor)
/ Distribution in horizontal and vertical dimensions
Remediation Practice &
Leaking tank... Transport..Receptors <^t^ Risk...,' ^
• .jt •«"—.,•«• f.J,^ - ~ ",. ]"'"'/!,;
I-V
Tank removal
Soil excavation
and ex situ disposal
In situ remediation of
*<"'«" ^oundwater... [ggG~^a,er piTST
rc/me containment...
Coupling
Source
removal starts
Contaminant
concentration In
pJume
^
treatment technologies
Source
PI n removal ends
\
^^^ *-*-"™ rwiiiiwwai
Remobilizatiori
'i.^- **" ~
^ "Steady from Remaining DNAPL
^^Attenuation
_ ^ — '-~~-^- MCL
Time
No-action or remediation
b
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Performance Verification of In Situ Remediation
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Technology Performance
What do we mean by "technology performance" ?
"Performance is a measure of a technology application with
respect to a specified function"
For example:
1 Treatment efficiency
~i Ease of implementation
"1 Site disruption and aesthetics
i Compatibility with long-term land use
~l Cost effectiveness
n Other...
How does "technology performance" fit into
remediation practice?
Technology Performance
As we set Site cleanup goals we must:
"i Define contamination in environmental media at some
location in space and time
e.g., t:sk-c^sca concentrations throughout a voiume of soli
T Define the needed technology performance with respect to
contaminant concentration, mass, mobility and tor toxicity
e.g., treatment ro reduce COC levels below drinking water ttnttts
Technology performance goals are set such that
achieving them would enable overall site cleanup
Technology Performance
Verifying potential
performance capabilities:
1 Based on contaminant and site
characteristics and process theory
~] Confirmatory testing and evaluation
completed during RAD projects
(e.g., Univ. R&D)
1 Standardised testing (e.g., SITE
program)
1 Standard of practice established
Irom project implementation at a
large number of sites
Validating actual performance
achieved at a single, specific
contaminated site ....
Site-Specific Validation
Approaches to validating performance achievement at a
specific site are based on:
Quantifying the reductions
in contaminant:
concentration,
mass,
mobility, and/or
tax/city Soil
and
Observing conditions
indicative of treatment
Ground
water
Plume
Site-Specific Validation
Validating that technology performance goals have
been achieved at a specific site is very challenging
1 Complex distributions of contaminants among phases
and aver space In the subsurface
t Difficulties to interpolate and estimate values at
unobserved locations
' Validation of performance against stringent cleanup goals
(e.g., drinking water standards)
"' Treatment technologies can affect the ability to validate in
situ performance (e.g., mass recovery vs. destruction]
Site-Specific Validation M
In general, the effective validation of in situ
performance at a particular site becomes more and
more challenging with:
~< Increasing site size and heterogeneity
T Presence of nonaqueous phase liquids
"' Cleanup goals that involve .
~l high mass removals ol contaminants
n very low levels ol residual contaminants
T Remediation technologies that require...
~1 long time frames
n don'1 readily permit mass balances
Site-Specific Validation
Quantifying contaminant concentrations
~i Technology goal is to decrease concentrations to some
ta rget level in soi I a nd/or ground water with i n some req ion
(e.g., yield 5 ppb TCE at the property boundary)
i Validate performance by media sampling & COG analysis
with statistical analysis for comparative purposes
"I Potential problems and challenges ...
~l Need lor large numbers of samples to address site
heterogeneities, and temporal and spatial variability
"1 Potential for large measurement errors (e.g., VOCs In soil)
1 Errors in Interpolation to estimate levels at locations without
measurements
1 Concentration changes may not be due to treatment (e.g.,. rate-
Jim tted pioccs•-!.--. dilution}
Site-Specific Validation
Potential measurement bias
due to sampling effects
Uncertainty in geostatistical
estimates of concentrations
Error and uncertainty in estimates of
concentrations and mass in the subsurface
Overcome by field methods, sensor
technologies, spatial modeling, etc.
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Performance Verification of In Situ Remediation
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Site-Specific Validation
Site-Specific Validation
Quantifying contaminant mass
~i Technology goal is to decrease mass to a target level in a
specified region of the subsurface
COC mass = Concentration x Volume x Density
COC mass reduction = (COC mass before - COC mass after}
~1 Validate performance by media sampling & analysis for
COCs with statistical analysis to estimate mass
~i Potential problems and challenges...
"I COCs can be distributed In a complex manner among phases
and In vertical and horizontal dimensions
"I Potential for large measurement errors {e.g., VOCs In soil)
i Error's In estimated levels al locations without measurements
~l In altu remediation can alter subsurface conditions jnd make
comparison of post-treatment masses Invalid
Site-Specific Validation
~i Validate performance using partitioning tracer tests to determine
pre- and post remediation NAPL distributions
~> Potential problems and challenges...
A Reliability for mixtures In heterogeneous conditions
& Effects of treatment tec hnology on (low and tracer behavior
A Waste generation and cost
Site-Specific Validation I
• Quantifying contaminant mobility
i Technology goal is to decrease mobility of COCs to some
target level in soil or waste within some region (e.g., yield 5
ppb TCE in teachate from treated waste)
"i Validate performance by media sampling & testing for COC
teachability with statistical analysis for comparative
purposes
~i Potential problems and challenges...
~i Need for large numbers of samples to address site
heterogeneities and temporal and spatial variability
"1 Potential lor large measurement errors (e.g.. VOCs In soil)
~i Errors In interpolation to locations without measurements
~l Extrapolating from lab test conditions to realistic long-term
Held conditions
Site-Specific Validation
Quantifying contaminant toxicity
i Tec hnology g oa I is to d ecrease toxicrty of COC to some
target level in soil and/or ground water within some region
(e.g., transform 100% of the Chromium from Cr*fl ro Cr3)
"i Validate performance by media sampling & COC analysts
with statistical analysis for comparative purposes
~i Problems and challenges ...
~l Need for large nunib«rs of samples to address site
heterogeneities and temporal and spatial variability
~l Potential for large measurement errors (e.g.. Eh changes)
"1 Errors IP Interpolation to estimate levels at locations wilhout
measurements
n Assessing long-term stability of observed performance
Site-Specific Validation
• Supporting manures
~i Measurements and observations of treatment conditions
other than direct observations of the contaminants being
treated In situ
• Examples:
1 Remote sensing and geophysical napping
~i Measurement of mass recovered (e.g., SVE off-gas)
n Measurement of reaction products (e.g.. CI-)
~i Measurement of biogeocnemical conditions indicative of
treatment process function {e.g., pH, Eh, D.O..
microbiology, chemistry,...}
Closing Remarks
In situ treatment technologies are increasingly being
used for remediation
Validating performance of in situ treatment and
achievement of a goal at a specific site can be
extremely challenging
Multiple types of data that demonstrate one or more
measures of treatment (concentration, mass, mobility
and/or toxic ity) are normally needed
Careful application of multiple monitoring and
measurement approaches and methodologies is
critical to effective validation at a specific site
Closing Remarks
• Some questions:
What are realistic expectations for validation of in situ
performance?
e.g., 95% mass removal with 90% confidence
What is an appropriate level of investment in validation
at a particular site?
e.g., 5% of total project cost? ...15%? ...30%?
Should the choice of an in situ technology for a specific
site depend on the ability to effectively validate
performance at that site?
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
NEEDS, VIEWS, AND CONCERNS OF THE REGULATORS
Victor Dries1
1. INTRODUCTION
Soil remediations absorb quite a lot of time of money. Most people don't really adore spending either of
these on a factor that doesn't seem to have a positive impact on the future results of the company. Every
party concerned is looking eagerly for means to make remediations cheaper and more efficient. In-situ
remediation technologies offer quite some advantages: they are often quite a bit cheaper than excavation
concepts, you don't spend all of your money at once, but spread payments over quite some years and the
use of your land can be more or less continued. In-situ treatment is not evident, though; the soil matrix is
very complex and prediction and optimisation of the process is very hard. Problems may arise at several
steps in the decision procedure.
2. SOIL INVESTIGATION
Every remediation concept starts with a soil investigation to know whether or not you have to remediate,
and to offer the data necessary for the evaluation of different remediation concepts and for the modelling
of the chosen concept. Yet, even soil investigations may pose quite a few problems.
2.1 Investigation Problems
Classical soil investigations have a number of limitations. A number of samples are taken on specific
places on a site. The information you get out of this is of course only relevant for the place where you
take the sample and even then, for the depth where you take the sample. Enough samples give you a quite
good idea of a site, but it will never be better than "quite good". You never know you haven't missed a
spot, you never know that the concentration of chlorinated solvents is the highest on the depth where you
have taken your groundwater sample. Apart of that, the question arises how you organise your site
investigation. Mostly, the first investigation (we call it exploratory) gives you a general idea of whether
your site is contaminated or not. The next investigation (we call it descriptive) tries to find the boundaries
of the pollution. Two procedures may be used to achieve this. Firstly, you tell the investigator to do take
as many samples as he likes, as long as you get the result as fast as possible. This may imply quite a large
lot of samples, and can be quite expensive. To avoid this, most people prefer a tiered soil investigation,
where a round of samples is taken and analysed; based on the results, a next round of samples is taken in
the most relevant direction. This procedure is more cost-effective, but takes a lot of time.
2.2 Alternatives
To avoid those problems, alternative detection and analysis technologies can be used, such as so-called
intelligent probes, mobile XRF, mobile GC, and geo-radar. Those technologies are still quite young,
though, and most still need thorough validation. Even when such a technology is validated, most of the
times a few classical samples need to be taken and analysed to verify the obtained data.
2.3 Laboratories
A very critical factor in soil investigations is the quality of the laboratories used. Samples are analysed
and the results are used to check whether or not certain standards have been passed of whether the
concentrations found pose any risk. A question most people dare not ask is what the relevance is of the
data obtained from the lab. In annex to this text, I put the results on organic compounds of a round robin
organised about 2 years ago among labs already accredited to analyse different sorts of samples (waste,
1 OVAM (Public Waste Agency of the Flemish Region), Kan. de Deckerstraat 22-26, B-2800 Mechelen, victor.dries@ovam.be
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waste water, ...). If the results of the round robin were positive, a lab also got the accreditation to carry
out analyses on soil and groundwater. The Flemish regulation implies that laboratories have to be
accredited in a double procedure: not only the instruments, personnel and procedures in the lab are
evaluated, but also a lab must prove its qualities in a round robin. This round robin was already the
second try; the results of the first run were so bad, we couldn't even use the data to do a proper statistical
analysis. Even though the labs knew the test was extremely important for them (access or not to a fast
growing market of soil analyses) the results were quite poor. Recoveries for e.g. benzene in soil ranged
from 4% up to 131%, for styrene from 10% to 182%, for dichloromethane from 1,5% up to 199%, for
naphthalene from 0,2% to 128%! In water recoveries ranged e.g. for octane from 3,5% up to 75%, for
tetrachloromethane from 62% to 194%, for 1,4 dichlorobenzene from 45% up to 174%, for naphthalene
from 17% up to 126%. I want to stress that the samples were all well homogenised and stored in optimal
conditions until taken in by the labs. How often is this true during soil investigations?
We were lucky, we found those problems, and we did not accept the labs with bad recoveries for soil or
groundwater analyses. Some of the labs we did not accept where quite big foreign labs, which were
accredited in their mother country according to "classical" accreditation systems (do you have quality
control procedures and do you follow them thoroughly). How many countries, though, have an
accreditation system where also the quality of the analyses is evaluated? Those problems forced us to set
up a system of blind controls of the laboratories, as we wonder what the quality of an analysis is when a
lab is not working for such an important goals as a market entry, but rather under the stress of delivering
results as soon as possible. For relatively volatile compounds, the problems are even larger, because it's
very hard to prevent loss during sample taking.
A lot of work still has to be done to improve analyses, and we have to view very closely if certain
parameters cannot be measured better in the field. What's the use of spending a lot of energy in a
thorough risk assessment if even your input is not sure? What guarantee do you get if a risk assessment
states that a risk is present, but that it's not really serious?
3. REMEDIATION
The Flemish soil remediation decree states that historical soil pollution needs to be remediated if the soil
contamination poses a serious risk for man, groundwater or environment. The moment of the remediation
depends on the priority given to the pollution (except when the ground is transferred; then the transfer
triggers the remediation). To remediate all historical soil pollution that poses a serious risk, a period until
2036 has been dedicated.
3.1 In-situ Concepts
In situ techniques are applied quite a bit at sites in Flanders, although I am skeptical about the ability of
current techniques to offer complete solutions. Pump and treat solutions are generally accepted, but with
the proviso that the chances of P & T offering a complete solution are not high. Poor site investigation
work often limits P&T effectiveness. Hydrogeological containment is used for managing active waste
sites, but is not popular as a remediation approach.
Soil venting and bioventing are popular technologies, and air sparging is growing in importance as a
remedial technique, all are well accepted by regulators. A recent study on emissions from these processes
indicates that the emissions control is of limited effectiveness, with significant transfer of volatile organic
compounds from soil to atmosphere. Currently used in situ techniques are not apt to deal with very severe
contaminations, as treatment times may span several decades. Most concepts offer not a complete
remediation of a site; on the long run, we have to take into account that when the use of the ground
changes, the contamination may pose serious risks again and that the future use may be hindered.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
I think the new boosting concepts that have been developed in the United States may offer solutions for
heavy contaminations, that cannot be solved in an easy way by classical concepts in a relatively short
time span. Good care has to be taken of the control of the system, as mobilisation of the contaminant
opens also the risk that contamination is spread beyond the present boundaries of the contamination or
even of the property.
3.2 Natural Attenuation
A second alternative that looks very attractive is natural attenuation. Just count on the biodegradability of
the pollutant, and make sure the pollutant doesn't leave your ground. To check this, a sound monitoring
system is installed. Sounds pretty good, but we have to focus on a few problems. Firstly, this monitoring
may last many years, thus implying important organisational aspects, as well as a cost that may prove to
be quite high on the long term. Secondly, we only accept a concept of attenuation if you can prove that
attenuation is taking place and is guaranteed on the long term. As attenuation depends on many factors, a
very good knowledge of the soil and of the soil processes is needed. Our experience is that very few
consultants have the experience and the know-how to do a good modelling and that the amount of data
needed to do this modelling requires a thorough (and expensive) soil investigation. If your problem is
quite big, this is no problem of course, but we still have the problem of the monitoring. Above, I already
stated that laboratory analyses are not always exact, even for parameters that are more or less common.
This problem is even much larger when one has to analyse parameters that are not common at all. A great
example is the degradation of chlorinated solvents. I have already heard very nice speeches of consultants
indicating that they measure a lot of parameters to prove attenuation is taking place, even vinyl chloride
and ethene. I know very few labs capable of analysing these parameters in a proper way. Even when you
find one, taking a sample, conserving it properly until it reaches the lab and sample preparation is not
evident at all of this case, so it may quite well be that the plume of dissolved product and by-products is
much larger than you measure. We are not very likely to accept this if the plume is moving towards a
neighbour who is not too far away.
3.3 "Stimulated Attenuation"
I like the term stimulated attenuation; however it's just a nice name for existing concepts. Either it's an in
situ remediation concept, or an attenuation concept where the source is removed, or a combination of
both, where the source is removed and afterwards an in situ treatment of the plume is started. I like them
quite a bit better than natural attenuation, because at least you have a decent idea that part of the
contamination is removed.
Especially the combination looks quite good, because most often in situ treatment without taking away
the source takes ages, and on the other hand a well designed in situ treatment can reduce the term of
monitoring with many years. Again, we have to stay critical to try design a treatment and to monitor the
plume as well as possibly.
3.4 Isolation Concepts
You can opt for alternative soil remediation technologies that don't take away the pollution in a short
term. A first one is isolation of the pollution. By isolation, you break the pathway and reduce the risk.
Isolation is quite often much cheaper than removal of the pollution for very large contaminations, but has
some disadvantages. Firstly, an isolation always implies a duty of care: whatever you do on a ground, you
have to take care that you don't break the isolation. This may pose problems, for instance when you want
to construct a new building on the ground.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
You have to take into account that the isolation has to be maintained; this can make foundations quite a
bit more complex (and thus more expensive). This also impacts the value of a ground when you want to
sell it. Secondly, each isolation needs to be monitored to make sure the isolation is still functioning well.
This monitoring is strictly spoken eternal; this implies important organisational aspects to make sure the
monitoring is assured and may imply important costs. Another disadvantage is that every isolation is
temporal: after a while the isolation will break down. I know of no system that has eternal life. A good
choice of the isolation concept is extremely important; as a basic principle, one can state that every more
or less "natural" system is safer than artificial concepts. To reduce infiltration of rain in a polluted area, I
trust more in a well-designed natural vegetation system than in an HDPE-liner. Producers of liners
currently use a 40 year-guarantee for their products, when their products are properly placed. A good
control of the installation of a liner is extremely important, but also extremely difficult. We have already
encountered landfills which had been covered 7 years ago and needed remediation, because the liner was
not properly installed. Even if the liner is properly installed, you have to be aware that after 40 years, your
isolation is quite likely to break down.
An isolation concept I really adore, are active walls. Firstly, the contamination is isolated; thus making
sure it poses no unacceptable risks for the surroundings. Where classical isolation concepts tend to be
almost eternal and require a good control of the permeability of the wall, the groundwater in this concept
can stream quite freely, as long as we are sure it passes through a treatment zone. Thus permeability
demands of the wall are a bit less stringent, the wall is quite often quite a bit cheaper, and in a middle-
long run most of the mobile fractions of the contamination moves through the active zone, where it is
remediated. Again we have to be aware that modelling of an active wall is not very easy, as you have to
know what processes you need in your wall. Such a wall also demands maintenance and sound
monitoring. The monitoring though may depend of the level of "self-control" the system can deliver. A
good concept of the wall can make sure that all contaminated water has to pass through the active zone,
and then monitoring of the activity of the zone can be more effective than monitoring behind the wall. In
this case, monitoring of the groundwater downstream of the wall can be reduced strongly.
4. CONCLUSIONS
I like in-situ remediation technologies quite a bit. They have quite some advantages: they are often quite a
bit cheaper than excavation concepts, you don't spend all of your money at once, but spread payments
over quite some years and the use of your land can be more or less continued. We have to spend enough
attention to good soil investigation and risk evaluation, as those are the basis to decide whether or not soil
remediation is necessary and how the risks can be controlled and reduced in the most effective way. We
have to be very careful, as risk evaluation by models seems to be quite exact, but many doubts remain.
One of the larger problems is the lack of guarantee offered by laboratory analysis.
Soil remediation is expensive, so we try to look for most cost-effective remediation concepts. Isolation
seems quite interesting for large contaminations in the short run, but it may pose organisational and
maintenance problems on the long run, as well as problems to transfer the ground. Natural and stimulated
attenuation seem very attractive, but we have to be very careful. A consultant has to prove that he knows
well enough all relevant soil parameters and that he can model decently what will happen in the future.
Monitoring of attenuation is not always evident and may prove to be rather expensive in the long run.
Most in-situ concepts offer not a complete remediation of a site; on the long run, we have to take into
account that when the use of the ground changes, the contamination may pose serious risks again and that
the future use may be hindered.
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Performance Verification of In Situ Remediation
5. PRESENTATION VISUALS ~ presented by Victor Dries
NATO/CCMS Pilot Project Phase III
In-situ treatment:
deus ex machina or
jack-in-the-box?
Victor Ones
Opt Soil Remediation
OVAM (Public Wteste Agency of the Flemish Region)
Randets, Belgium
mpact legis
Remediation goal: BATNEEC
- if possible: background level
- if not possible: < SRS
- if not possible: no risk
Soil investigation
Investigation problems:
-samples give limited information (hor.+vert.)
- good information of contamination implies
either a lot of money or a lot of time
Alternatives:
alternative detection + analysis methods
Iwatch out for on-field validation
mpact legislation
New contamination:
immediate remediation when > SRS
SRS depend on soil use
Historical contamination
remediation when risk
at moment transfer or after priority
In-situ treatment
Pump and treat is well accepted
- offers little guarantee
- often used with too little study
- recalcitrant contaminations take very long
Soil venting (and bioventing) is quite
popular and well accepted
Air sparging is growing and quite well
accepted
Soil investigation
Laboratories
- very little quality assurance
- value of accrediation systems?
- round robin for accreditation
Recoveries ordiehlororaethane in soil
128,8% 73,2% 92,6% 116.7%
117,1% 134,8% 99,6% 10.6%
1,5% 196,6% 121,3% 99,0%
101,4% 84,5% 91,2% 199.2%
88.5% 100.6% 107.3% 76.8%
89.7%
Natural attenuation
*• many data needed: expensive inves
difficult modelling
*- monitoring: long + difficult
«- laboratory results
*• neighbours are often very near
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Natural attenuation
• "Enhanced" attenuation
- source removal
- in-situ treatment
vpart of contamination is removed
Vfaster
f-good modelling + monitoring
Source boosting
» Mobilisation of recalcitrant
contaminations
• Reduces time frame P&T strongly
• Almost unknown in Europe so far
<" Hydraulic control of mobilised
contamination
Containment (2)
Containment
Hydrogeological containment used on
waste dumps in use
Containment walls and "wrap and
dump" quite popular for big problems
Active walls coming, not easily
accepted
Immobilisation in active study
*• nothing has eternal life: semi-natural
concepts vs liners
<• contamination stays present
^active walls
$• duty of care+maintenance
*• future use
*• monitoring: self-controlling system?
Reliability of lab analyses?
Good modelling is necessary
Good monitoring is expensive and hard
Maintenance is important
Isolation and attenuation may impact
future use+transfer price
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
NEEDS, VIEWS, AND CONCERNS OF THE SITE OWNERS
Terry Walden1
1. ABSTRACT
In-situ remedial systems generally fall into two category types. The first is a Stationary system that
involves the use of installed wells (or trenches) for moving air or other remedial fluid through the
formation. In these systems the soil is left relatively undisturbed. The second system is a Disruptive
system where the soil is physically disturbed to achieve treatment. Examples here include landfarming or
in-situ soil mixing with large augers.
Remedial performance validation is dependent on the type of system employed. Sentinel wells at the
downgradient boundary and within the footprint of the treatment area are normally used for a Stationary
system, where the goal is for all (or at least 95%) of the sentinel wells to meet a risk-based clean-up
concentration. In a Disruptive system, it is typical to place a regular grid pattern over the area following
treatment and take samples at each node to verify that the target has been achieved. The grid is sized so
that any untreated - or less than satisfactorily treated - area has a radius less than a specified maximum.
While conceptually it would be appealing to perform grid-based verification on all remedial systems, site
owners would be very reluctant to agree to this approach on Stationary system designs. Experience has
shown that such systems typically take longer than specified - and may require additional infill wells - to
achieve the promised goals, or may never achieve the objective within a satisfactory time frame. Even
more fundamentally, the heterogeneous nature of an undisturbed soil media almost guarantees that some
zones will by bypassed, typically those having a lower permeability where contamination may be
concentrated. So having typically spent additional money and time to achieve a clean-up target on the
sentinel wells, site owners would be leery of sampling additional locations where one exceedence could
delay a real estate transfer (even though it may little impact on overall risk). If a gridded validation were
specified by the regulator at the time the system decision is taken, it could well result in selection of a
more predictable ex-situ remedial design.
2. INTRODUCTION
This paper expresses the perspective of the site owner with regard to the validation of in-situ remediation
performance. The site owner view in this case is the oil company, BP, and the experience shared is BP's
European practice on the topic. The experiences discussed are not to suggest that these are BP's policies,
but simply the approach that is commonly taken at BP's retail stations, terminals, lube plants and
refineries in Europe.
3. BP'S PRESENCE IN EUROPE
BP has operating sites or plants in 10 countries in Western Europe, including the UK, France, Benelux,
Germany, Austria, Switzerland, Spain, Portugal, Greece and Turkey. In addition there are a few countries,
like the Scandinavian countries and Italy, with a lubricant presence due to the recent acquisition of
Castrol. In-situ remediation systems have been installed in most of these countries over the past several
years. Primarily these consist of soil vapor extraction systems for treating soils in the vadose zone, and air
sparging systems for in-situ treatment of groundwater. In addition, in-situ systems for free product
removal include dual or multi-phase extraction using a high vacuum blower.
1 BP Oil International, Chertsey Road, Sunbury-on-Thames TW16 7LN, United Kingdom. Phone: (44) 1932-771938; Fax: (44) 1932-
763439; E-mail: waldenjt@bp.com
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4. REMEDIAL GOALS
Other than in jurisdictions where it is prohibited, remedial goals in BP are generally determined on a risk
basis. There are actually few (or no) countries in Europe where a risk approach is explicitly stated as
unacceptable, although there are always local regulators to whom the process may need to be
demonstrated and validated before getting their approval.
Remedial goals generally start with a requirement to remove a certain amount of- perhaps all - the free
product in wells. The treatment endpoint in this case is a thickness of product not to be exceeded in one or
more wells across different seasons. Note that free product usually manifests itself to the greatest extent in
the dry season when water tables are low.
Human health or ecological risk goals generally require achievement of a soil and/or groundwater
concentration that meets acceptable risk criteria. So the overall remedial goals at a site are generally to
leave no more than a minimum thickness of free product in certain or all recovery wells, and to achieve a
soil/groundwater concentration protective of human health and the environment.
5. SYSTEM CLASSIFICATION
For purposes of validating performance, in-situ systems can basically be broken down into two types:
a. Stationary Systems: By this is meant that the soil is left relatively undisturbed by the remedial
system, with only wells (or perhaps trenches) installed for in-situ treatment. Examples are soil
vapor extraction, air sparging or multiphase extraction wells.
b. Disruptive Systems: In this case the soil is disturbed in order to treat it. In-situ examples include
landfarming (where the surface soil is tilled to facilitate bioremediation) and soil mixing (use of
large augers to mix biological or chemical reagents with the soil or to stabilize it by introducing a
cementing mixture).
6. REMEDIAL VALIDATION PRACTICE
From a site owner perspective, the method of validating remedial performance is a function of the type of
system installed:
a. Stationary Systems: It is preferred to have a series of sentinel wells identified for achievement of
the remedial target concentration. These wells are typically not the vapor extraction or sparge
wells, as these wells would receive preferential treatment by virtue of being part of the remedial
design. The sentinel wells are normally located at both the downgradient boundary of the site and
within the footprint of the treatment area. The layout of the wells within the footprint should be
such that achievement of the target at their locations assures overall treatment of the whole of the
remedial area.
b. Disruptive Systems: When the soil has been disturbed for treatment, the preferred validation
approach is to grid the site for validation monitoring. The grid is normally a square or rectangular
pattern with a spacing appropriate for ensuring that any inadvertently untreated, or less than
satisfactorily treated, source zone has a radius less than a specified maximum. Again the targets
to achieve are generally risk-based concentrations.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
7. CONCLUSIONS AND DISCUSSION
The use of sentinel wells for stationary systems and a validation grid for disruptive systems seems fairly
straightforward. A good question to ask however is why a validation grid is not used for all in-situ
systems, regardless of type.
Site owners would not be happy to have a validation grid for stationary systems. One hidden message
here concerns the lack of confidence in stationary in-situ systems. This is especially true in countries
which have traditionally conservative standards, such as Germany or the Netherlands, where meeting a
target is difficult. In some cases the systems have not been able to achieve the promised remediation
target within the scheduled time frame and often, additional treatment wells must be installed to reach
areas or locations in the soil column where the air does not appear to travel. In certain circumstances, the
systems have been abandoned in favor of a dig and dump scheme at significant cost while also delaying a
potential real estate transfer date.
There may be plausible reasons for the shortcomings of the in-situ system. Perhaps it was ill suited for the
geology or contaminant type. Perhaps the design was flawed with too large a spacing between wells. But
more importantly, it is probably unrealistic and asking too much of a system to achieve very detailed
clean-up over a wide area in a media (soil) where there are natural heterogeneities, such as low
permeability strata. These anomalies can trap contamination and are un-amenable to treatment by air-
based systems where the flow may bypass them.
Having normally spent additional time and money to achieve a risk-based concentration target at all the
sentinel wells, operators would be very reluctant to open the site up to gridded monitoring from new well
locations. The likelihood is too high that lower permeability untreated zones may be encountered, thus
further delaying the closure or sale date, even though concentration exceedences at a few wells would
likely have a negligible impact on the overall human health or ecological risk. If a gridded requirement
were specified by the regulatory authorities in advance of the decision on the remedial system, it could
likely change the outcome in favor of an ex-situ disruptive system, such as composting or thermal
desorption.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
8. PRESENTATION VISUALS -presented by Terry Walden
NATO Special Session
Validation of In-Situ
Remediation
Site Owner Perspective
Terry Walden
BPOil -London
September, 2001
Common Remedial Goals
1. Free product removal to minimum thickness
SORWAKMICUMMJK
2. Soil & groundwater concentration targets
protective of human health & environment
• •• JB
In-Situ Remedial Systems
Disruptive Systems
D Landfarming
n Soil mixing with
large augurs
soil is disturbed
• •• j *
Disruptive System Validation
Grid Monitoring
D Square or
rectangular grid
a Sampling at
nodal points
BP Retail Market, incl. Aral
• > 18% market share
O 10-18% share
ID < 10% share
D no BP Retail business
In-Situ Remedial Systems
Stationary Systems
D Soil va po r extraction
wells or trenches
a Air sparge wells
D Chemical flush wells
soil left undisturbed
Station
Stationary System Validation
Sentinel Wells
o Downgradient
boundary A
D Within footprint of
treatment area o
Netherlands Terminal; Target of 1 ug/l benzene - all wells
Why Not Grid Monitoring Everywhere
D Experience with Stationary Systems in Europe
* Generally take more time and money to achieve clean-up
goals
D Inherent Limitations of Stationary Systems
+ Heterogeneities in soil (esp. lower permeability media) may
be unavailable to air flow •
•
a Difficulty with One 'Hit' Above Target •
» Regulotory impasse even though it may have little impact j
on overall risk
• •• JB .!••
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Conclusions
D Current validation protocol is Tit for purpose1
* Sentinel wells for well-based remedial systems
+ Srid monitoring when soil media fully disturbed
o Complete 3-D clean-up with Stationary systems
unrealistic, but
# Impact ort overall risk from one 'hith small
» Natural attenuation likely to take care of problem
o Imposing grid monitoring everywhere could result in
more use of ex-situ technologies or 'dig and dump'
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
NEEDS, VIEWS, AND CONCERNS OF THE INSURANCE COMPANIES
Dominique Ranson1
1. SUMMARY
Investigating and redeveloping contaminated property used to have more risks than benefits. The
potential for environmental liability or unknown cleanup costs often turned an attractive real estate deal
into a financial nightmare.
Environmental insurance has made investment in contaminated property less risky over the past decade.
The insurance industry has found solutions for environmental uncertainties by offering pollution
insurance for known, as well as unknown environmental liabilities.
A site cleanup project for known environmental liabilities represents, in general, one of the most
important environmental liability exposures. Insurers have developed their own specific way to assess the
insurability of a clean-up program via a review of the remedial action plan, contemplation of containment
of the cleanup costs within the insurance program, and inclusion of unknown as well as known pollution
conditions in an environmental insurance program. Environmental insurance now permits optimization of
internal risk management capabilities and prevents the break down of property transfer negotiations due
to uncertainty associated with known or unknown environmental liabilities. Conclusions will be
illustrated during the lecture with claims scenarios and cases in which insurance solutions facilitate
property transactions.
2. KNOWN VERSUS UNKNOWN POLLUTION CONDITIONS
A property owner can protect himself against unforeseen and unexpected cleanup costs that are above the
anticipated cost for a cleanup project by purchasing Cleanup Cost Cap insurance. These known pollution
conditions are always within the self-insured retention and the Cleanup Cost Cap insurance is excess of
this self-insured retention.
Pollution conditions may also be unknown because there is no relevant data on the historic use of the
property, the pollution or its consequences (cleanup, bodily injury, property damage) have never
manifested, or current legal obligations or orders by the authorities may significantly change. These types
of environmental liabilities may be insurable as unknown pollution conditions.
3. POLLUTION AND ENVIRONMENTAL LIABILITIES
Polluted sites often result in third party liabilities. These preexisting conditions resulting from historic site
operations or gradual releases typically are not insured within the classical general liability insurance
program in Europe, with a limited exception for Germany, where certain types of facilities have the
obligation to buy coverage for third party liability related to pollution conditions (UHV). However, on-
site cleanup costs are almost in every case not insured and even excluded. Policy wordings must be
carefully reviewed, particularly when more than one policy is in place: Not only "known" versus
"unknown" but also origin, causality, sudden & accidental versus gradual coverage, primary versus
excess (UHK- lower retention/ deductibles under one policy verses another) as well as historical pollution
issues may become serious sources of discussion in a claim situation when more than one policy is
involved.
1 Environmental Insurance Manager AIG Europe. Kortenberglann 170-B-1000 Brussel
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Clean up of soil and groundwater is generally expensive, can be unpredictable and can turn into a
financial nightmare. In some European regions, soil and groundwater contamination already jeopardize
property transfers and lease and rental agreements.
In order to be able to provide insurance, the insurance industry has techniques to assess the likelihood of
occurrence of unknown environmental liabilities and the uncertainty related to environmental cleanup.
The likelihood of occurrence of unknown environmental liabilities is essentially assessed by examination
of the underwriting information. This underwriting information consists essentially of detailed data
regarding site history, dangerous goods and waste storage management, dangerous goods processing and
transport, environmental compliance and management, security, hydrogeological characteristics, air and
surface water emissions and sensitivity of the neighborhood.
4. MOST IMPORTANT UNCERTAINLY FACTORS RELATED TO ENVIRONMENTAL
LIABILITIES
4.1 Site Related Factors
One of the most important site related factors in the site history. During the environmental underwriting
process the site history is assessed in detail because it contains relevant information with regard to the
potential presence or absence of different types of pollutants resulting from improper waste handling
(buried waste), gradual releases over the facilities operating history, effluent discharges, etc... The site
history may also explain the presence of third party liabilities or other outside influences. In some cases
due diligence audits or phase I environmental audits contain sufficient site history information.
Sometimes more investigation may be required by the underwriter to fill gaps prior to underwriting the
exposure. Some site related factors are site or facility specific. Those features are essentially related to the
local environment (such as use of land, surrounding land use, presence of drinking water wells, natural
resources (lakes, rivers, streams...), the general exposure to third parties related to the pollution and the
extent of the contaminants.
Especially with regard to cleanup cost potential, knowledge of surface soil and groundwater
characteristics is essential. In most of the European region the environmental authorities require risk-
based assessments in relation to the necessity and efficiency of cleanup. Factors such as permeability,
transitivity, depth of groundwater table and ground water vulnerability, clay/organic matter content,
presence of ground water wells and their application, hydrogeologic characterization... are typical data
required for the environmental underwriting process.
Sites under exploitation on which environmental cleanup occurs or will occur need specific attention with
regard to the management of the site. In general, environmental management, dangerous goods storage
and distribution, waste handling and storage, are important risk factors and may cause additional pollution
conditions or complications during cleanup. Also of vital importance is the accessibility to third parties
and the way construction and remediation are implemented by the contractor.
4.2 External and Other Factors
Environmental underwriting requires a good understanding of the expertise and experience of the
environmental consultant working for the insured as remedial expert. One of the basic requirements is the
presence of a multi disciplinary team working within the environmental consulting organization, as site
assessments and remedial design require such a multi disciplinary approach. The ongoing exponential
development of new remedial technologies requires sufficient up-to-date know-how of the environmental
designer. Especially in those regions where the local authorities are part of the cleanup project, the
environmental Consultant Company must be able to provide local specialized employees able to negotiate
with local authorities or other official bodies.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
In order to be able to assess the comprehensiveness of the remedial budget (or self-insured retention), the
level of investigation performed is elemental.
The most important factors are:
• Degree of reliability of the laboratory results
• Geostatistical criteria related to the sampling of soil and ground water
• The sampling procedures and representativeness of the analyzed samples
• Degree of reliability of site history analysis, data on subsurface soil and ground water characteristics,
site features and analysis of the extent of the contamination.
In many cases, environmental law, future use of the property, surrounding environment, exposure to
public and the environment, will influence the way in which cleanup has to be performed.
Depending on the attitude of the public towards the facility of the insured (and its eventual
contamination) the requirements of the degree of cleanup could become completely different form that
expected in a "normal" or similar situation elsewhere. It is therefore crucial to be aware of any known or
reported claims, pending claims, consent orders, prosecutions, against the insured. Public perception
generally does not influence the obligation to cleanup (which is based upon environmental law). Public
perception will however push the insured to be more compliant and environmentally conscious.
Unexpected clean up costs are in many cases related to the (sometimes) unpredictable conduct of the
pollutants, unknown historic uses of the property, surrounding operations, or poor delineation.
Knowledge, therefore, regarding hydrogeological conditions and hydrodynamic behavior of the
pollutants, historic uses of the property and proper investigations are essential. Because in many regions
the environmental authorities apply a risk based approach, it is also essential to understand the biological
attenuation and the toxicology (including the availability) of the pollutant.
Environmental authorities are a significant party within the remedial cleanup process. Their attitude
influences the way cleanup will be performed and their likelihood of changing their orders. The political
factors, sensitivity of the authorities towards pollution and the legal frame are criteria of consideration
during the environmental underwriting process.
5. INSURABILITY OF ENVIRONMENTAL (SITE) CLEANUP
5.1 How are Environmental Risks Dealt with in Terms of Underwriting?
Environmental insurers rely primarily on their own evaluation and assessment of the factors stated above
rather than on insurance industry loss statistics.
Many property and general liability losses with environmental causalities are generally not reported as
environmental losses. One of the most important distinctions to be made is the difference between known
and unknown pollution conditions, as there is generally no possibility to insure known losses, above
environmental law, on a risk transfer basis.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Figure 1: Loss -, frequency and knowledge indices determine the field in which environmental insurers
are willing to participate in the risk (RT or risk transfer section). Outside this delineated field, whereof
shape and extent is on a case-by-case level, the risk/loss is within the SIR.
Frequency
Knnu ledge index
For known pollution conditions however, there are possibilities to insure in excess of the self-insured
retention (SIR). This self-insured retention level also depends on the know-how on existing pollution
conditions and environmental care (Figure 1).
Statistical know-how based upon experience with similar cleanup projects, loss history analysis of the
site, and knowledge of privileged partners (external and own consultants - in the case of AIG, AIG
Consultants, Ltd.) gives the insurer the ability to offer environmental insurance solutions. Other
extremely important consideration criteria in the underwriting process are the results of the detailed
analysis of the remedial action plan and the financial strength of the insured. In-house environmental
underwriting experts do environmental underwriting at AIG.
5.2 Environmental Insurance Solutions
In the case of presence of known conditions on which a cleanup is legally required, the insurance industry
is able to provide coverage for the costs in excess of the SIR. This insurance solution is called: Cleanup
Cost Cap insurance.
Unknown pollution conditions and third party liabilities are generally covered by site-specific
environmental insurance policies, such as the Pollution Legal Liability policy, perfectly fitting between
property and liability insurance policies. Especially in those cases in which property transactions occur,
brownfields are developed, multiple year coverage is necessary or balance sheets protections are required,
blended insurance programs (such as the environmental protection program) provide tailor made
solutions.
6. CLEANUP COST CAP PROGRAM
The Cleanup Cost Cap policy indemnifies the insured for cleanup costs, as defined in the remedial study,
that are above the anticipated budget for cleanup of the site or facility. The policy offers coverage for
cleanup costs at, adjacent to, or from a defined site location. The coverage consists of an attachment over
the SIR, which is generally equal to the expected costs of cleanup plus a buffer layer (Figure 2). For the
known pollutants, there's coverage provided in the event:
34
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
• The actual contamination is greater than estimated
• Off site cleanup is required adjacent to the covered site
• Off site cleanup due to emanation of the pollution from covered site
• Governmental authorities change orders in course of the cleanup project
The policy covers the remedial action plan, becoming a part of the policy and describing exactly the area
in which environmental cleanup occurs. The Cleanup Cost Cap also offers an option covering newfound
contamination while conducting the cleanup. This option also includes coverage for cleanup in case off-
site contamination from those newfound pollutants occurs from the covered location.
Figure 2: Basic insurance structure of the cleanup cost cap program: The SIR is equal to the expected
costs of cleanup plus a buffer layer. Above this SIR there is a cost overrun coverage (a "cap" or excess of
loss). Premium discounts are available in case the insured participates in the excess of loss section.
Numerical example: SIR= 2,240,000 Euro; cost overrun coverage= 3,760,000 Euro
Buffer
Expected
costs
The information required to underwriting a Cleanup Cost Cap policy includes the environmental site
assessments (phase I, II, risk assessments (REBECCA, C-SOIL, Volasoil etc.), hydrogeological
assessments, etc.), the remedial action plan (including different cleanup alternatives and budget estimates)
and the eventual agreement with the contractor who will execute the remedial work.
The Cleanup Cost Cap (CCC) properties at AIG are:
• 100,000,000 US$ available per site
• Multi-site programs can be offered
• In suitable for blended insurance solutions
• Terms up to 10 years available.
7. POLLUTION LEGAL LIABILITY
AIG's Pollution Legal Liability policy (PLL Select) generally provides coverage for operations facilities.
The coverage includes on-site and off-site cleanup from pre-existing and new pollution conditions, on-site
and off-site third party bodily injury as well as on-site and off-site third property damage due to pollution
conditions. The insurance program can be tailor made (different basic coverage options) depending on the
risk-management needs of the (insured). In addition to the insurance program, PLL Select offers coverage
for business interruption and transportation to and/or from a covered location. There's generally no
distinction made between sudden or gradual pollution, because in many claims scenarios it is almost
35
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
impossible to differentiate between the two. The policy trigger of PLL Select is the legal obligation to
carry out environmental cleanup. Coverage is provided for owned, leased or rented sites.
The PLL policy doesn't provide coverage for existing contamination (this is done by the Cleanup Cost
Cap policy), but provides coverage during the policy term in case pollution conditions arise, which is not
covered under new found conditions in the Cleanup Cost Cap policy, a cleanup is required. PLL can be
combined with a CCC program or can be purchased after execution of the remedial work.
8. BLENDED INSURANCE: ENVIRONMENTAL PROTECTION PROGRAM
By means of example of blended insurance solutions, the Environmental Protection Program (EPP) gives
the ability to combine numerous advantages related to environmental insurance:
• The policy creates a well defined scope of action
• There is an excess coverage provided
• Expected costs are discounted
• Rewards are provided in case of favorable loss experience
• Provides high guarantees in case of property transaction
• Protects budgets and balance sheets
The Environmental Protection Program is, technically speaking, a combination of a finite risk insurance
construction (RF) and an excess of loss coverage (Figure 3). For example, a known condition might
require environmental cleanup and is associated with a budget of 10,000,000 US$. The legal obligation to
execute cleanup may be expected within the first 10 forthcoming years. The known potential loss is
ventilated over this period, resulting in a net present value (NPV) over the amount of years. The average
NPV is a criterion to determine the RF premium. In addition to the RF section, the insurer provides an
excess of loss coverage.
Figure 3: Environmental Protection Program construction
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Many claims are also associated with discovery presence of unknown pollutants during the execution of
the environmental cleanup (such as asbestos, pesticides, PCB's, etc). Claims vary between 20-300% of
the SIR.
10. CONCLUSION
Environmental underwriting can not be compared with the daily way of underwriting risks in the
insurance industry. It requires a detailed assessment of all kinds of factors that might influence the extent
and scale of known and unknown pollutants. Environmental liability exposures, whether known or
unknown, can jeopardize property transactions, as they are normally insufficiently insured or not insured
at all within the general liability or property insurance programs (the classical insurance). Environmental
insurance is the adequate answer to situations in which financial guarantees are required to cover
environmental liabilities. Environmental insurance and blended insurance programs are oftentimes
purchased in cases of mergers and acquisitions and brownfield development situations. Contractors are
also interested to offer coverage for cost overrun due to environmental cleanup. Insuring the
environmental liability might create financial advantages such as off-balance sheet and budgetary
protection.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
11. PRESENTATION VISUALS ~ presented by Dominique Ranson
Program
T Insurance: basic principles
T Environmental liabilities.
known or unknown
- cleanup required or not?
T Insurability of environmental (site)
cleanup and liabilities?
T Solution:
cleanup cost cap
- Blended insurance: EPP
- PI.I,
v Claims scenario's '
Insurance: basic principles
v Insurance • financial protection against
losses with unforeseen character
T Classic Insurance: unforeseen equals
sudden and accidental
T Casualty: insurance for third party losses
(general liability)
T Property: first party coverage (own
property, premises....): fire insurance.
boiler & machinery...
Environmental liabilities
Known or unknown pollution
Polluted sites can result in third party liabilities
v The cleanup of soil and ground water is generally
expensive, sometimes unpredictable
T In some Kuropcan regions, soil and ground water
contamination jeopardize property transfers
T Site history, dangerous goods and waste storage.
dangerous goods processing and transport are very
important
[.ease and rental agreements
Most important uncertainty
factors related to cleanup
T Site related factors
Sile history
- Subsurface soil and ground
water characteristics
Sile- management
other site features
Most important uncertainty factors
related to cleanup (2)
v External, other factors
experience and expertise of environmental
consultant
level of investigation performed
public perception
- eiinduct of the pollutants
attitude of the authorities
\~
Site history
T Pan of the site characterization is the site
history. In some cases die site history is
insufficient documented in phase 1 studies
T The site history explains the potential
presence or absence of different types of
pollutants or buried waste
. It also may explain the presence of third
party liabilities or outside influences
V
38
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
(surface soil and
jundwater characteristics
T Pcnueabilily
T Transmissivily
T deplh of grounduatcr table
T Yiilnaribility of the ground water
"• clay/organic matter content
ground water wells
'm Site Management
En\ ironmcmal management
v Accessibility for third parties
T Dangerous goods storage and
distribution
T Waste handling and storage
T Construction works
Other site features
T Typical examples are the presence of
buried waste of chemicals (barrels).
T Other features are:
- local environment (use ofland. presence
of drinking water wells. ...)
- general exposure related to the pollution
extend of the contamination
Aid!
A »•*« tf AHttRS.**..] CIMI
Experience and expertise of
environmental consultant
T Site assessment and remedial design
requires a multi disciplinary approach
T Exponential development of soil and ground
water cleanup technologies require
sufficient up-to-date know how
T Local presence (especially in cases in which
negotiations \\ ith local authorities arc
v —Required) is essential
Level of investigation
performed
T Degree of reliability of laboratory
results
Geostatistical criteria
* Sampling procedures
T Degree of reliability of
- Site history analysis
- subsurface soil and ground water
characteristics
- site features
- analysis of the extend of contamination
nublic perception
T What's the attitude of the public
with relation to the facility (and
eventual existing contamination)
T Any known or reported claims.
pending claims, consent orders.
£±±r:°°
conduct of the pollutants
v Hydrologies) conditions and hydrodynamtc
behavior ol pollutant is an essential
now ledge in order to predict the possible
conduct of the pollutants (in future and
during cleanup)
v as environmental authorities apply more
and more a risk based approach it is
essential to understand the biological
availability) or the pollutant
loxicolocv
ttitude of the authorities
T Political factor is very important
T Sensitivity to the pollution
T There is a significant evolution
towards a risk based approach in most
of the European countries
1 legal frame
T likelihood of changing orders
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
urability of environmental
nC) cleanup
T How is dealt with environmental risks
in terms of underwriting?
T What arc the environmental insurance
solutions'.'
- Clean-up Cost Cap
Hnvironmental Protection Program
Pollution Legal Liability
How is dealt with
environmental risks in terms
of underwriting?
A. General
T Environmental undcrw riling (third
part) liability and cleanup cost) only
relies to a very small part on
statistics
T All potential items/factors as slated
above need to be investigated
m
How is dealt with
environmental risks in terms
of underwriting? (2)
li. known pollution conditions
T Statistical know how is essential based
upon experience with similar projects, loss
histories and knowledge of our dedicated
consultants (AIO Consultants Ltd.)
T Detailed analysis of remedial action plan
T Financial strength of the insured
\~
How is dealt with
environmental risks in terms
of underwriting? (3)
C. Unknown conditions and liabilities
T Relevant and sufficient underwriting
information is necessary.
T SIR-level depending on know-how on
existing pollution conditions &
environmental care
T Underwriting is done by environmental
experts
What are the environmental
insurance solutions?
v Known conditions and cleanup required:
Clcan-up Cost Cap
T Unknown conditions and third parlx
liability: Pollution Legal Liability
T Blended insurance solutions:
Environmental Protection Program
Cleanup Cost Cap
T Indemnifies the insured for cleanup costs, as
defined in the remedial study, that are above the
anticipated cost of cleanup.
.' Coverage is provided for cleanup costs at. adjacent
to. or from the defined site location.
,' The policy attaches over a prescribed self-insured
retention. (SIR), which is generally equal to the
expected cost of cleanup plus a buffer layer.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Site- boundary
Remedial action plan
Known contamination
How does it work (4)?
Covers Remediation Cost Overruns for:
Actual contamination greater than
estimated.
TOffsite cleanup costs adjacent to the
covered site.
T Offsite cleanup costs emanating from
the covered site.
^ How<
w does it work (3)?
Covers Remediation Cost Overruns for:
T Actual contamination greater than
estimated.
TOffsite cleanup costs adjacent to the
covered site.
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Performance Verification of In Situ Remediation
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', How does it work (5)?
Covers Remediation Cost Overruns for:
T Actual contamination greater than
estimated.
v Offsitc cleanup costs adjacent to the
covered site.
T OlTsilc cleanup costs emanating from the
covered site.
T Change orders required by governmental
authorities that are incurred during the
• policy term.
Ootional
New Found Contamination
Coverage:
T Cleanup costs ofa new found
contamination that is discovered while
conducting the action plan.
' Includes cleanup costs for offsilc cleanup if
the offsitc contamination emanated from the
covered location.
Site - houndurv
Rfiiii'di;il action plan
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
ic Structure:
T Coverage attaches above the
expected clean up.
TPremium discounts are available
if the insured elects to have the
coverage attach excess of a buffer
layer.
Alternative structure
Co-insurance or risk
participation (contractors.
third parties, insured) in stop
loss layer
Properties
T l(H)Mio€ per site limits available.
T Multi-site programs can be olTered.
T Blended insurance possibilities
v Terms of up to ten years available.
Underwriting information
v Environmental site assessment reports
(phase I. II. risk assessment.
hydrogcological assessment....)
T Remedial action plans
v Contractor's agreement
v Mergers/acquisition agreement
_ Benefits
-Helps assure that funds will be available for
entire cleanup of contaminated site
-Protects against financial loss that could
inhibit owners' operations and profitability
-Satisfactory to a lending institution, which
may be fearful of incurring liability or losing
the value of the loan
-Property can be put back to productive use
while protecting human health and the
environment
Unknown conditions:
Pollution Legal Liability (PLL)
Coverage for sites in exploitation
Coverage includes the following:
- Oil-site ;md Oil-site eleannp eosts from pre-
existing and new pollution eondilions
- On-site and off-site third party bodily injury
- On-site and off-site Ihird party properly damage
- Transportation to and or from the location
- Business Interruption
PLL (2)
.' PLL doesn't cover remedial plans (such as
CCC) but provides coverage during the polic\
term in case a remediation needs to be done
(for new. gradual or pre-existing conditions)
v It fits perfect bctw ecu property and liability
policies and optimi/es the risk management
T It can be combined u ith a CCC program or is
purchased after cleanup
T Responds to "gaps" in classical insurance
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Environmental Protection
Programs
^Manuscript Policy Forms.
TExpected Costs are discounted.
TExcess coverage is provided.
yRewards for favorable loss
experience.
A mmitim ttAmmtiSSRt*
Case studies
T Single sile acquisition
w company
Single Site Acquisition (1)
'ingle site acquisition (2)
T A company IVir sale owned a contaminated
location w hich deterred prospective
purchasers.
T Brmviifielcl developer was willing to purcha.se
property and clean it up.
T Seller minted assurance that developer had the
ability and financial support to accomplish.
T Bv acquiring a contaminated property,
the Brownfield Company could be held
liable for all environmental conditions,
old and new. at the subject site by virtue
of holding title to the property.
T The remedial action plan for the site
required financial assurance for closure
and post-closure activities.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
'm Single Site Acquisition (3)
w Company
Solution'.
T Cleanup Cost Cap to protect against cost
overruns associated \vith the known
conditions.
v PLL Select was purchased to protect
against liability arising from unknown pre-
existing and nc\\ pollution conditions at the
subject site.
• A large company estimated outstanding
environmental liabilities in the S4(>0
million range for a portfolio of
properties.
The companies objective is to divest the
assets and liabilities to form a new
company.
New Company (2)
Problem:
T The liabilities represented the cost to
complete or begin remediation at the sites
which were all in various stages of
cleanup.
T Some locations were owned, others were
non-owned w here the company was a
potentially responsible party.
\ ' -
originally proposed resulting in inert
Claims Scenario 2 Cleanup
Cost Cap
T SIR: $2,260.000 Claims : $1.200,000
T Cause of Loss
Additional contaminated soil discovered al sile.
Original cost estimate included costs associated with
UST upgrades, project planning . pre-cons tract ion
activities and capital improvements. was considered
to be a part of ihc Remedial Action Plan.
Laboratory analysis, consulting costs. ... not
included in the cost estimate from the consultant
Claims Scenario 3 Cleanup
T SIR: 2.67IMKM) Claims: 7.800.01K)
T Cause of Loss
geology.
Unknown pollutants
> Asbestos discovered
Claims scenario 4: Pollution
Legal Liability
'Claim: 10.000.000 USS
' Polluted site was investigated in detail
T Regulatory agency issued no further action
letter
v Unfortunately NFA letter had provision
clause (can be revised)
T Contaminants, local situation, adjacent
properties and re-evaluation show need for
clean-up
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
ims Scenario 5: Pollution
,gal Liability
v Claim: 2.00(1.000 USs
T Company producing plastics had a lire explosion
T Due to the presence of lire extinguishing \\ater
soil and ground \\aler got contaminated
T Fire insurance is not paying for cleanup eosls
(only removal ol debris)
T Regulatory bodies required cleanup ol"
contaminated soil and ground water (oil.
plasticizers. dioxin....)
Why purchasing environmental
insurance?
T Meets to specific requirements to
obtain financial guarantees
r Essential in mergers and acquisitions
T Bro\\ nfield developers and contractors
have high interests
v OFT balance sheet protection
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF SOIL VAPOR EXTRACTION
Michael Altenbockum1 and Oliver Kraft2
1. ABSTRACT
In 1998 data from a number of soil-vapor remediation projects have been reviewed in a research project.
The results revealed that most of the reviewed projects showed deficits in important features as field
testing procedures, technical standards and criteria for starting, implementing and stopping soil-vapor
remedial action. The results also made clear that there is a big demand for standardized procedures and
technical guidance in dealing with volatile contaminants in the unsaturated zone.
The German Association of Remediation Engineers (ITVA) will publish directions in the near future that
will provide standards for field-testing and data collection. Together with a recently published direction
by the environmental state authorities of Nordrhein-Westfalen / Germany, these two publications will
provide technical standards as well as criteria to evaluate the effectiveness of soil vapor remediation
projects. They also deal with quality control and quality assurance (ITVA) and strategies for terminating
soil-vapor remedial action (LUA).
If remedial goals cannot be met, a key number for the evaluation of remedial effectiveness is defined as
the specific energy consumption. If specific energy consumption is calculated as being not within
tolerable limits, it is suggested that the remedial concept has to be reviewed critically or remedial action
should be terminated.
2. INTRODUCTION
In 1998 environmental authorities in Nordrhein-Westfalen launched a research- and development-project
to investigate different approaches to soil vapor extraction (SVE) in practical remedial projects. The aim
of the research project was as follows:
1. Explore the state-of-the-art of this technology which is meant to be a proven technology,
2. compile the fundamental knowledge about SVE,
3. develop guidelines for SVE remedial practice which should end up in a guidance document and
4. define the frame conditions for an optimized application of this technology.
In the research project, data from one hundred remedial projects and 146 treatment plants from all over
Germany were collected and evaluated. To avoid any bias it was made sure that not more than four
projects per source were used. The sources were consulting companies, cities, counties, state agencies and
others, public and private. Furthermore, laboratory testing has been carried out to gain a broader
knowledge about the extraction properties of contaminants under ideal, laboratory conditions.
When evaluating the collected field data, the main focus was put on the following points:
• Field tests of extractions before starting remedial measures,
• documentation of remedial goals and rationale for their specification,
• documentation of procedures to evaluate the effectiveness of remedial action (e.g. effective radius of
extraction, extractabilitiy of contaminants, mass balance, etc.).
1 Altenbockum & Partner, Geologen - Aachen, Germany. http://www.altenbockum.de
2 Altenbockum & Partner, Geologen - Aachen, Germany. http://www.altenbockum.de
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
The following points are given to summarize the results of the data evaluation:
Field-testing before remedial measures:
• In only sixty-five percent of the evaluated case studies extraction tests were carried out in the field
before remedial measures were started.
• The duration of the tests ranged from a couple of hours to 99 months [which, in the second case, led
to the conclusion that no further remedial action is necessary in this case!].
• In 26 percent of the field tests there were no provisions to treat the off gas.
• None of the field test data sets were considered and implemented in the subsequent design of the
treatment plan. Frequently, it was concluded that the process applied during the test would also be the
best process for the remedial measures.
Remedial goals:
In Germany, remedial goals are usually specified as numeric goals - as numbers. The specification of
these numbers can be named more or less arbitrary because it is frequently done without consideration of
the site conditions. Mostly, remedial goals were set up by supervising authorities. Having a look at the
numbers that were used as remedial goals, it looks like a "Who has the strictest regulations "-contest has
evolved between authorities in charge (Figure 1). The result was that in more than 70 % of the cases, the
remedial goals could not be met.
Figure 1: Comparison of remedial goals in field applications (LUA 2001).
40 -
5 10
Remedial Goals In mg/m LCHC
20
Another number that is usually specified by supervising authorities is the off-gas concentration. A
technical standard by the German Association of Engineers (VDI) from 1999 provided guidance by
giving numbers as maximum levels for contaminant off-gas concentration. These numbers have become
mandatory for many, if not the most remedial measures. However, these maximum emission
concentrations have to be criticized especially in housing areas, where the maximum concentration levels
are obviously too high.
But using adequate technical features and the appropriate technical design of the plant could reduce this
problem. In most cases, the off-gas is treated by adsorption of contaminants on activated carbon. It is well
known that moisture content plays an important role in the performance of the activated carbon.
Adsorption on activated carbon is much less effective with moist gas. There is no activated carbon
producer in Europe who gives any warrant for the performance of his activated carbon with moist gases.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
With feed gases having the moisture content of natural soil vapor and contaminant concentrations around
or below 50 mg/m3, the performance of the activated carbon is not really good and the contaminated soil
vapor could not be treated properly. Nonetheless, clean-up criteria and remedial goals are specified in this
range every day.
Performance and effectiveness of remedial action:
Not all substrates are suitable for using soil vapor extraction as the remedial measure of choice. So, the
minimum result of a soil vapor extraction test is to evaluate if soil vapor extraction is an adequate
remediation technique or it is not suitable for the given site conditions. The one criterion that is directly
connected to substrate properties is the determination of the soil volume influenced by the extraction. The
proof for the influenced volume is the determination by measurements of the under-pressure in
neighbored monitoring wells. This determination of the range is used to prove that a negative pressure
could be established in the full extension of the contaminated zone.
Data for this determination are gathered during the extraction test and the actual remediation in a
representative monitoring grid. Frequently, qualitative tests like smoke candles are used, but data revealed
from these kinds of tests are not representative and therefore the conclusions about effectiveness based on
those kinds of data are not objective. On the other hand, it is an open question if data gathered from
quantitative measurements are only numbers describing negative pressure conditions or if those numbers
can be used to evaluate the effectiveness of a remedial measure. To come closer to an answer for this
question, we should have a close look at the theory and at some results from laboratory and field tests.
In 1997, the German Association of Engineers published mathematical approaches for the determination
of the treatment ranges of SVE. These approaches used ideal conditions (homogeneous sediment with no
organic content and zero moisture). Based on these theoretical approaches and depending on some
boundary conditions (e.g. screen length, screened zone oft the subsurface, diameter of the well, grade of
ground surface sealing), it provides an equation and also an analytical solution which allows to calculate
the under pressure of a point at a given distance from the well and therefore to calculate the width of the
treatment range of SVE. It is well known that in most of the 'real world' cases the conditions in the
subsoil are everything but ideal, and they usually cannot be explored in very deep detail. It is therefore
more than questionable if mathematical models are really helpful.
Information could again be gained from the research project described several times before, although
during the information collection only a limited number of representative data sets could be found. For
comparable soil types, in this case fine to medium sand, something like a general trend could be found.
This trend was checked in a remediation test at a dry-cleaners site by extracting vapor from different
extraction wells in different constellations and monitoring seven wells by under-pressure measurements.
Here, negative pressure has been controlled several times during the one-week test. Figure 2 shows a
diagram of the results, which were surprising, since obviously there is a negative linear dependency
between the under-pressure in the monitoring wells and the distance between monitoring wells and the
extraction well. This statement is true for all monitoring wells except KP3, which shows significantly less
under-pressure. An explanation for this phenomenon could be found in the files: a massive concrete
foundation could be detected between the extraction well and this particular monitoring well, lowering the
radius of influence in this direction. All in all, it has to be considered that it is not really clear if other
specific site conditions had an influence of the data from this particular field test, since we were not able
to further investigate the specific conditions with regards to other inhomogeneities.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Figure 2: Determination of treatment zone diameters (FlachenRecycling, 2000).
__ 4 -
3 -
3456
Distance from Extraction Well [m]
10
But the effectiveness is not only dependent from site / subsurface conditions, but also from specific
properties of the contaminant. To evaluate the extractability of different chlorinated hydrocarbons
standardized laboratory tests were also part of the research project. Those tests have been carried out by
using a column filled with 1.8 kg of fine sand and 20 g of chlorinated hydrocarbons. Moisture content has
been set to 90 % and the temperature during the test was adjusted to 20° C.
Different test series have been done with negative pressures of 1, 5, 10 and 25 mbar, these pressures can
be reached in field tests and remedial action under good field conditions. Figure 3 shows a typical
example of a concentration curve that was revealed with negative pressures of 10 mbar. Other tests with
different negative pressures showed similar results. The concentrations curves of 1,1,1-trichloroethane
(111-TCA), trichloroethylene (TCE) and tetrachloroethylene (PCE) are different due to the natural gas
law and the Henry constant.
In the beginning, the concentration is high. The reason is the balanced condition in the closed laboratory
system. After a while, concentrations decreased rapidly and after a test duration of 48 hours, the
efficiency of the extraction was detected to be low and not sufficient. No single test showed a
contaminant removal higher than ten percent within the test period. If concentrations had remained stable,
treatment times of several years would have been necessary to achieve a sufficient contaminant removal.
These results from evaluation show that in remedial practice, there are a lot of unknowns that have to be
taken into account in the planning of soil vapor remedial action. Some of those questions about the status
of soil vapor extraction in practice can be summarized as follows:
• What are optimal conditions for SVE in the subsoil?
• What is the influence of moisture, temperature and organic carbon content?
• How can optimal conditions be established?
• What happens with the contaminants in the subsoil under these optimal conditions?
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Figure 3: Contaminant concentrations in the Extraction Tests at 10 mbar Negative Pressure (LUA 2001).
21 25 31
Tlme(h)
3. DEVELOPMENT OF SUFFICIENT REMEDIAL CONCEPTS
In 1997 the Federal German Soil Protection Act was released. This besides a lot of other things it states,
that if sufficient suspicion of a hazard is given, further investigation may be required. But when the act
was released, some people may have been disappointed, because no evaluation criteria, no numbers for
the evaluation of soil vapor concentrations to specify the need for a soil gas remediation were given. Soil
vapor is not mentioned at all in this act.
Yet, there are no guidance's available to classify contaminant concentration levels in the soil gas.
However, the soil protection act requires the use of numeric quality standards and orientation values (for
soil) during decision making as a basic principle. But still, some people need these numbers also for soil
vapor extraction.
All decisions according to the Federal German Soil Protection Act should be based on the evaluation of
risks from the contamination on different receptors. According to the law, these receptors are water, soil
and human health. One exemplary question is, why should the same concentrations of a contaminant pose
an identical level of hazard to different receptors?
In Germany only the state of Hessen has identified orientation values for the evaluation of soil gas
contamination (Table 1). But these numbers were not designed as limits to decide whether to start
remedial action or not. They have been set up to function just as indicators if further investigations should
be carried out, the decision about remedial action has to be based on these further investigations, which
should focus on the evaluation of the different pathways mentioned above. These investigations include
analysis of contamination in solids, groundwater and indoor ambient air as well as the conduction of
column tests (leachate prognosis).
51
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cane.
LCHC
I. BTEX
Benzene
1 mg/m3
5 mg/m3
< 1 mg/m3
1 mg/m3
5 mg/m3
< 1 mg/m3
Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Table 1: Orientation values for soil gas concentrations (LUA 2001).
Orientation Values for Soil Gas
Groundwater Indoor ambient Soil
air
I. LCHC 5 mg/m3 5 mg/m3 5 mg/m3
1 mg/m3
5 mg/m3
1 mg/m3
With defining orientation values under the described conditions, the state of Hessen showed that they
have realized the problem of strict regulations just based on numbers without taking into account the
circumstances of any unique case. We should keep in mind that especially for soil vapor contaminant
concentrations unique criteria are obviously the wrong approach. The pathways have to be investigated.
These are the ambient air and the leachate.
If the evaluation of the pathways results in the decision, that there is no hazard, no action will be
necessary. If some indicators for hazards are found, the need for remedial measures must be stated. One
of those indicators may be adequate concentrations of volatile contaminants in the soil vapor.
The evaluation of results from soil vapor investigations can be very difficult, because frequently soil gas
data lack reproducibility. Practical experiences have shown that these data sets are very often not
reproducible by repeated sampling and measurements in the field. Some of the potential reasons are:
• Further influx of contaminants,
• missing documentation of the sampling procedures,
• matrix effects in the non-saturated zone of the subsoil, and
• unknown additional soil vapor properties (e.g. moisture-content).
It is obvious that authorities responsible for the Federal Soil Protection Act and the underlying ordinance
knew, that it is not possible to derive soil vapor contaminant concentrations plausibly from solids-
concentrations and vice versa. Therefore, soil gas concentration values are missing in these regulations.
As true as this statement is, it doesn't help in the daily remedial practice.
The definition of a hazard is one step towards a remedial action. The other one is a remedial investigation,
which must document the need for remedial measures. With respect to this, the main point of a remedial
investigation should not be the continuing examination of site conditions but more the development of
remedial strategies to avoid or reduce hazards in the particular case.
The remedial investigation has to prepare and support the official decision making process on the type
and extent of the remedial measures. It should include interim remedial goals and also an evaluation of
the applicability and sustainability of potential technological options. The general goal is always to reduce
contaminant potential.
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Performance Verification of In Situ Remediation
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4. DIRECTIONS AND REGULATIONS
To support the steps mentioned above, a number of general rules and regulations have been developed by
the German states and in engineering associations. These directions and regulations have been designed to
formulate the requirements of the different investigation steps according to the Federal Soil Protection
Act as well as to standardize methods and techniques used during the investigational work.
As an approach to standardize appropriate procedures and techniques used with SVE remediation
projects, the German association of remediation engineers ,,ITVA"will issue direction for SVE field tests
in fall 2001. The research and development project mentioned above was taken as one basis for those
general rules. The direction includes clear recommendations for the duration, the technologies, the
sampling, documentation and data-evaluation. Some important points will be described briefly in the
following part of this paper.
It should be obvious that a SVE field test should be the basis of any SVE remedial action, but the results
of the R & D project in Nordrhein-Westfalen showed clearly that the accomplishment of a reproducible
field test is not a standard at all. Table 2 summarizes the technical features of a standardized SVE field
test. With this standard it will hopefully be possible that field tests reveal datasets that allow the
evaluation of the extractability with respect to the subsoil conditions and that can be used as a basis for an
appropriate SVE plant design. It will also make it possible to compare results from different sites.
Table 2: Standards for SVE field-testing (ITVA 2001).
• Duration of Field Test: 5-10 days;
• Technical setup:
Design of extraction- and monitoring wells:
Inner diameter: 50mm, 1 m tubing, 2 m screen-tubing
Gravel-package: 0.5 m clay, 2.5 m gravel
Distance between extraction- and monitoring well: 5m and 10m
Water- (= particle-) separator;
Compressor: 250±50m3/h,240±30mbar;2.4±0.4kW
Adsorption-unit: 1x200 liters, 70 -80 kg activated carbon
• Sampling:
Feed gas after 0.1h, 3.0h, 24h, 48h, 96h (=theend of the test)
Off gas after 24h, 48h, 96h (=the end of the test);
• Documentation of the sampling;
• Sampling with field measurement of volumetric flow rate,
temperature, moisture in feed and off gas streams;
• Evaluation of results regarding the need for remediation,
estimation of consumption of activated carbon and energy,
development of a sampling and analytical program for the
remedial action, short report.
The technology to perform the extraction testing is suggested according to internationally accepted
standards. Remarkable is the waiving of an additional safety filter unit behind the adsorber. The safety
filter can be ceased in routine five-day tests. However, it may be necessary if contaminant mass fluxes are
expected to be very high and there is a risk of contaminant breakthrough. This evaluation has to be
conducted prior to the test.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
For the evaluation of SVE field-test results, a number of datasets are needed. These data can be divided
into two groups:
1. Quality assurance data: - feed gas temperature,
- moisture content of the feed gas,
- oxygen content of the feed gas.
2. Performance data: - moisture and dew point of the feed gas,
- volumetric flow rate,
- under-pressure in the extraction well,
- under-pressure in the monitoring wells,
- contaminant concentration-curve,
- contaminant mass-flux,
- energy consumption,
- specific energy consumption.
To ensure the comparability of contaminant concentration data, only two sampling methods can be
accepted as adequate: adsorption of target compounds on activated carbon and gas-samples in crimp-cap
VOA-vials in a septum-cap under overpressure. The latter need to be injected directly into the GC in the
following analysis procedure. The direction includes helpful information about the selection of the
appropriate sampling method.
5. QUALITY CONTROL AND QUALITY ASSURANCE DURING REMEDIAL ACTION
The mentioned guidance's and regulations intend to contribute to an improved quality assurance in SVE
application. These include the evaluation of applicability of SVE, the planning and design of remedial
action and the control and supervision of remedial measures. Most documents are considered being well
on-track, because the technical parts are based upon practical field experiences as well as on theoretical
fundamentals. Both elements, practical and theoretical, have to be considered
To enlarge the pool of useful and reproducible information as a basis for future SVE projects, there is an
obvious need for Quality Assurance (QA) and Quality Control (QC) during all periods of SVE
remediation projects. The following issues appear to be of special importance to this subject:
• Sampling as a foundation for quality management (data gathering),
• calculation of mass streams and mass balances, and
• evaluation of data.
Quality assurance and quality control with respect to data gathering can be assured by using appropriate
equipment and well-trained staff. All sampling should be done with consciousness about potential sources
of error. One comparably simple way to avoid a large number of problems related to the subject of data
gathering is to use a mobile sampling tube (Figure 4) with probes for temperature, moisture, flow rate,
oxygen-content and negative pressure, which allow a parallel registration of relevant QA/QC-data. Data
can be recorded in an electronic data logger; simple connection plugs allow a mobile use at different
sampling locations in a plant.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Figure 4: Mobile sampling tube (ITVA 2001).
sampling measuring point oxygen pressure velocity
point for moisture and probe probe probe
temperature
111 111
All relevant data have to be identified in the planning phase and an appropriate monitoring program has to
be installed. These data are necessary to calculate mass streams at relevant points within a plant (input -
process steps - output) and to set up a mass balance for the complete plant. This is a suitable way to
plausibly document mass fluxes and fate of contaminants and water in the plant as well as energy and
activated carbon consumption rates.
Figure 5: Characteristic concentration curves and conclusions (LUA 2001).
Parameter
Contaminant
Concentration
mg/m3
Tendency
Tendency
increasing
Tendency
unclear
Tendency
decreasing
1
°
0
Concentration
0
j
c
^ — — • " Prognosis
'
1 3 24 48 96 h
Prognosis
1 3 24 48 96 h
\
\
N Prognosis
3 24 48 96 h
Comments
Defendable prognosis of the
further concentration curve is not
possible
Extraction well Is not located In
the center of contaminated
area.
Prognosis of the further
concentration is uncertain
It needs to be checked If an
extension of activity Is
necessary.
Extraction well is located in the
center of contaminated area
Contlnous decrease allows for
a reliable prognlsls.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
In combination with the calculation of mass fluxes, the development of contaminant concentrations with
time are of great importance with respect to the evaluation of performance during SVE field tests as well
as during the subsequent remedial action. Figure 5 shows 3 characteristic concentration curves and gives
also general interpretations of the curves.
The examples show that reliable data are the basis for plausible conclusions. Plausible conclusions are
essential for the acceptance during negotiations with permitting authorities. Quality assurance / quality
control promotes acceptance and allows efficient remediation.
6. STRATEGIES FOR TERMINATION OF REMEDIAL ACTION
The "ideal" SVE remediation project, like any other remediation project, is terminated when contaminant
concentrations are below the remediation goal. Then, remedial action is stopped and a monitoring starts to
assure the success of the remediation. But what happens if the remedial goals cannot be met in a
reasonable time? Then, a new strategy has to be applied. The keyword is feasibility of remedial goals.
There have been some approaches to describe the "effectiveness" of remedial action and to define criteria
when to terminate it. The LUA-direction (2001) defines specific energy consumption as the critical
criteria. Based on those criteria, it suggests a flowchart for the decision whether or not terminating SVE
remedial action (Figure 6).
It is defined as the amount of energy that is needed in the particular case to remove one kilogram of
chlorinated hydrocarbons (LCHC) from the unsaturated subsoil using SVE. The critical value is 1000
kWh (Kilowatt hours) per Kilogram (kg) LCHC. If less then 1000 kWh/kg LCHC are needed, the SVE is
regarded being efficient.
With specific energy consumptions between 1000 and 2000 kWh per kg LCHC, SVE projects should be
critically reviewed and a discussion about modifications should be made. Possible solutions to increase
the effectiveness of SVE remedial measures may be modifications in plant configuration and/or to
continue the remediation in an alternating mode. This means switching the extraction system on and off in
specific time intervals.
If more than 2000 kWh of energy are needed to remove one kilogram of LCHC, the soil vapor extraction
is insufficient or not a suitable method. Then, SVE remedial action should be terminated and different
remedial concepts have to be developed.
The critical values of 1000 or 2000 kWh/kg LCHC have been diverted from the R+D project mentioned a
couple of times before. There, more than 400 single extraction phases have been evaluated. The values for
specific energy consumption in these project phases have been calculated between more than 8 kg of
removed LCHC per kWh and 125.000 kWh for one kg of removed LCHC. Of course, these values
depend on the contaminant potential in the subsoil. If there is a significant contaminant potential, there is
a good chance of removing the contaminants effectively. On the other hand, the results show clearly that
some contaminants cannot be removed no matter what amount of energy is used in the remedial measure.
Data collected in the research project mentioned before showed that a large number of soil-vapor
remedial projects have to be evaluated as being ineffective with respect to those criteria (Figure 7).
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Figure 6: Decision Support for Termination of SVE remedial measures (LUA 2001).
When reviewing the effectiveness of SVE as a remedial measure, the first step should be to check the
conceptual approach for plausibility for this particular case. Therefore, the following data are needed:
• Review of all site-specific data (e.g. geology, soil characteristics, contamination in plane and depth,
investigations, contaminants/components, development of contaminant levels with time, etc.),
• Components and configuration of the treatment plant,
• Performance data.
If it is found out that the SVE remediation does not work effectively, optimization of the configuration
and/or components of the present measure have to be reviewed critically. Possible options for
optimization may be more extraction wells or exchange of plant components / modification of
technology. Another approach may be in a critical review of remediation goals with respect to site
conditions and potential risks from the contamination.
If no concept to optimize the performance of SVE remedial action and remedial goals are found to be
suitable, we have to conclude that SVE is not the right technology for the remediation of the subsoil in
this particular case and different technologies and approaches have to be discussed.
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Performance Verification of In Situ Remediation
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Figure 7: Specific energy consumption in SVE remediation projects (modified after
Altenbockum & OdensaB (1998).
SV unsuitable
100
SV to check
SV efficiently
* » »*»
200 300
400
mass flux [kg LCHC]
7. CONCLUSIONS
If we want to apply soil vapor extraction and if we want to assure quality, we have to meet the right
boundary conditions. In a risk-based approach for evaluation of the necessity of remedial measures, the
decision has to be based upon the realistic chance to remove the contaminant-potential for the different
receptors. Therefore, the reduction-potential is the crucial factor for the identification of a remedial
necessity and for the choice of an appropriate remedial method and technology. Therefore, this decision
should not be based on contaminant concentration levels alone.
SVE is without doubt a suitable remediation technology to reduce or remove contaminant-potential in the
unsaturated zone if the site conditions and the contaminant potential are appropriate. The suitability of
SVE as the remedial method of choice must be proven by a standardized extraction field test. The results
of the field test have to be considered in the evaluation of remediation necessity and design of the
remedial measure. Field test data must also comprise the deduction of the expected efficiency of the SVE
application. The criterion of specific energy consumption is considered to be suitable for the choice of
technology as well as for a critical review of an operating remedial measure.
8. REFERENCES
1. ALTENBOCKUM, M., ODENSAfl, M (1998): Die Bodenluft in der taglichen Sanierungspraxis. -
TerraTech. - 6/1998
2. ALTENBOCKUM, M., LIESER, U., LOHAN, N, KRAFT, O. (1999): Neue Ansatze bei der
Durchfuhrung von Bodenluftabsaugversuchen. - Flachenrecycling. - 3/1999
3. \TVA (Hrsg.) (200I/in press): Richtlinie Bodenluftabsaugversuch
4. LUA LANDESUMWELTAMTNRW(2001): Arbeitshilfe Bodenluftsanierung. - Materialien zur
Altlastensanierung und zum Bodenschutz
5. VDI (Hrsg.) (1999): Emissionsminderung, Anlagen zur Bodenluftabsaugung und zum
Grundwasserstrippen. - VDI-Richtlinie 3897
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF SUFACTANT-COSOLVENT FLUSHING
Leland Vane1 and S. Laura Yeh2
1. SUMMARY
The use of surfactant and co-solvent solutions to remove non-aqueous phase liquids (NAPLs) from soils
has seen significant research and development activity over the last decade. These soil flushing
technologies are now entering the full-scale implementation stage of their development. Since
performance assessment is critical to the acceptance of a new technology, methods for assessing the
NAPL removal efficiency of soil flushing technologies have been concomitantly evaluated and
developed. In this paper, several performance assessment approaches will be described and the use of
these approaches during a surfactant-based soil flushing field demonstration project will be detailed.
2. INTRODUCTION - FLUSHING TECHNOLOGY BACKGROUND
Soon after recognizing the importance of removing NAPL sources to reducing long term risks and costs, a
number of "flushing" technologies were investigated. In this approach, one or more chemicals (alone or
as an aqueous solution) are introduced into the NAPL-contaminated subsurface zone and caused to flow
to a collection system under a hydraulic gradient. These chemicals act to enhance either the solubilization
or the mobilization of the NAPL, or both. When the additives are co-solvents, the desired result is the
solubilization in a homogeneous single-phase solution. Often, such a result is achieved at relatively high
co-solvent concentrations, generally greater than 50 wt%. Alcohols ranging from ethanol to pentanol and
higher have been evaluated for this application (Jawitz et al. 2000, Sillan et al. 1998). In some cases, the
co-solvents will partition into the NAPL to an extent which alters the interfacial tension properties, thus
causing NAPL migration.
The addition of surfactants to the flushing solution can result in both solubilization and mobilization
(Butler & Hayes 1998, Chevalier et al. 1997, Shiau 1996). Surfactants (surface active agents) are
molecules composed of two differing parts: a hydrophobic tail and a hydrophilic head. Because of this,
surfactants accumulate at interfaces such as air-water interfaces or water-NAPL interfaces. By tailoring
the properties of the surfactant, significant reductions in interfacial tension can be achieved, thus allowing
the movement of NAPL trapped by capillary forces. In general, as the concentration of surfactant is
increased, the interfacial tension is reduced. However, at a concentration referred to as the "critical
micelle concentration" or CMC, surfactants form self-aggregates referred to as "micelles" (Rosen 1989).
The CMC is determined by the properties of the surfactant and the aqueous solution. Below the CMC,
surfactants are present in solution as individual molecules called "monomers". Any surfactant added
above the CMC will aggregate into micelles, although monomers will still be present at a concentration
equal to the CMC. It is the monomer concentration that most effects interfacial tension. Thus, interfacial
tension reaches a minimum when the surfactant concentration is 1 CMC and stays fairly constant for
surfactant concentrations above 1 CMC.
Micelle structures are such that the hydrophobic tails of the surfactant molecules intermingle to form a
hydrophobic core while the hydrophilic head groups form a (usually) spherical outer "shell". As depicted
in Figure 1, molecules of the NAPL compounds will partition into the hydrophobic core, thus raising the
apparent solubility of the NAPL compounds in the aqueous solution. The number of surfactant monomer
units in a micelle (the aggregation number) is fairly constant for a particular surfactant/solution system.
As surfactant is added above the CMC, more micelles, all of approximately the same size, are formed. As
a result, the solubilization capacity of the micellar solution increases as the surfactant concentration
increases. The increase in apparent solubility can be several orders of magnitude. For example,
1 U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 W. M.L. King Dr., Cincinnati, OH
45268 USA. Ph. 513-569-7799, Fax 513-569-7677, e-mail: vane.leland@epa.gov
2 U.S. Navy, Naval Facilities Engineering. Service Center, Code ESC411, 1100 23rd Ave., Port Hueneme, CA 93043 USA. Ph. 805-
982-1660, e-mail: vehsl@nfesc.navv.mil
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
tetrachloroethylene (PCE) solubility increases from 240 mg/L to -100,000 mg/L upon the addition of 4.0
wt% Alfoterra 145-4-PO sulfate™ surfactant and 16.0 wt% isopropyl alcohol (IPA). Addition of 0.18
wt% CaCl2 to the system raises PCE solubility to 700,000 mg/L (Duke Engineering 2000).
Flushing solutions are delivered and extracted via screened wells. Thus, proper design, installation, and
operation of the well field and flow rates are critical to the success of in situ flushing technologies.
Subsurface flooding simulators, such as UTCHEM (Brown et al. 1994, Delshad et al. 1996), combined
with hydrogeological and biogeochemical data for the subsurface formation, NAPL, and flushing solution
allow for design optimization and the estimation of process efficacy.
3. PERFORMANCE ASSESSMENT FUNDAMENTALS
The performance of soil remediation technologies has traditionally been assessed using groundwater
monitoring and/or soil sampling. The former assumes that a unique relationship exists between the
aqueous concentrations observed at a monitoring well and the mass or volume of NAPL in adjacent
portions of the aquifer. Unfortunately, this assumption is patently invalid because of the diffusion and
solubility limitations of the NAPL components; therefore groundwater monitoring is inaccurate for
assessing the performance of a NAPL remedial action. Under ideal conditions, the analysis of soil
samples will yield a satisfactory performance assessment. However, this requires that the samples be
representative of the unsampled regions and that all sediments and interstitial fluids are recovered from
soil samples. Thus, spatial variations in NAPL distribution and soil heterogeneities must be minor for soil
sampling to be an accurate performance assessment method, and proper sampling tools and sampling
procedures must be followed to maximize recovery of all solids and liquids from a soil sample.
Otherwise, the number and size of samples necessary to obtain an accurate estimate of the NAPL mass
within a subsurface volume must be impractically large. One of the main issues related to soil sampling is
the representative elementary volume (REV) which is the volume of soil required to yield a single sample
representative of the region being sampled (Mariner et al. 1997). In many cases, the REV is larger than
the volume of typical soil samples. Thus, accurate information concerning the local NAPL saturation and
distribution is difficult to obtain using soil samples.
To address issues related to REV, a relatively new method of NAPL characterization and remediation
performance assessment, called partitioning interwell tracer tests (PITTs), has been introduced (Jin et al.
1995). In this technique, an aqueous solution containing multiple tracers is injected via wells into the
NAPL-contaminated formation. The tracers are selected to provide a range of water-NAPL partition
coefficients ranging from conservative (non-partitioning) tracers to highly partitioning compounds. Most
of the tracers are straight- and branched-chain alcohols. The tracers are then recovered at another well or
set of wells. The appearance of each tracer at the recovery well is a function of the retardation of transport
caused by partitioning of the tracers into the NAPL phase. In fact, the tracer concentration vs. time
relationship observed at the recovery wells is quite similar to that observed during the chromatographic
analysis of compounds - tracers which do not partition into the NAPL appear first and at relatively high
concentrations. Those that have high partition coefficients appear later and tend to have significant peak
tailing. Examples of tracer recovery during PITTs in the presence and absence (or near absence) of NAPL
are shown in Figure 2a and 2b, respectively. The mathematical manipulation of the tracer concentration
curves yields an estimate of the NAPL residual saturation (Sn) in the subsurface region swept by the
tracers (Wilson et al. 2000, Mariner et al. 1997, Jin et al. 1995, Dwarakanath et al. 1999, Rao et al. 2000,
James et al. 2000). Similarly, interfacial tracers can be used to estimate the NAPL-water interfacial area
(anw) (Rao et al. 2000). Multi-level sampling (MLS) devices positioned between the injection and
extraction wells can yield information about the vertical variation in NAPL saturation (James et al. 2000,
l. 1998).
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
PITTs have a number of limitations and cannot be applied to assess all remediation technologies. Current
methods of analyzing PITT data assume that the following conditions exist:
1 Tracer partition coefficients (K) are accurately known
2 Reversible sorption of tracers to sedimentary organic matter has been quantified
3 Tracers penetrate all parts of the NAPL zone including:
a. Free-phase NAPL zones
b. Low intrinsic permeability or low relative permeability zones
4 Multiple tracers with a wide range of Ks used
5 Sufficient time provided to assess tracer signals from all parts of NAPL zone.
Due to these assumptions, the ability of PITTs to accurately account for pooled free-phase DNAPL is
limited. In addition, high levels of soil heterogeneity can result in tracers having reduced or no access to
low permeability zones, for example into clay lenses. Thus, PITTs most effectively estimate NAPL
saturation when the NAPL is fairly uniformly distributed as residual ganglia (Wilson et al. 2000).
A measure of remediation performance can be obtained by comparing the results of PITTs performed
before and after the remediation. The use of PITTs for this purpose is relatively independent of the
remediation technology employed. When applied to the performance assessment of in-situ thermal
remediation (ISTR) technologies, the timing of the post-treatment PITT as well as the thermal stability of
the tracers used will be an issue. Because of their inherent similarities, PITTs and enhanced flooding
technologies are particularly well-matched. When conducted prior to the soil flushing process, the PITT
design can be incorporated into the remedial flood design, due to the similar flow dynamics. The
assumptions listed in the paragraph above must be true for both the pre- and post-remediation PITTs. If
the flushing process alters any of these properties, then they must be separately determined for each PITT.
For example, if the flushing process alters the makeup of remaining NAPL, then the water-NAPL tracer
partition coefficients must be measured again. Such may occur when a surfactant is used to remove a
complex NAPL consisting of organics with variable viscosities from the subsurface. A complex NAPL
treated using a thermal technology may experience similar difficulties in the use of PITTs due to the
preferential removal of NAPL components of low volatility. Flushing processes may also affect the
sorption of tracers to the soil, for example if the fraction of organic content of the soil is altered.
Therefore, tracer soil sorption must be characterized before and after the remediation.
Finally, monitoring of the extracted flushing solution as well as samples obtained from MLSs and other
sampling wells during the flushing process will yield a direct and real-time measurement of remediation
performance. The mass of NAPL compounds solubilized by the flushing solution is calculated by
integrating the contaminant mass flow rate (concentration times flow rate) vs. time data for the extracted
fluid. The sum of this solubilized mass and the mass, if any, office product NAPL recovered yields the
amount of NAPL removed due to the remediation. This amount can then be compared to initial NAPL
mass estimates or to NAPL removal estimates obtained from soil sampling or PITT data. A mass balance
on injected chemicals should also be conducted by integrating concentration data obtained from
extraction wells to evaluate the efficiency of hydraulic containment. This is important as high residual
concentrations of injected chemicals following surfactant/co-solvent treatment may cause unintended
migration of solubilized chemicals beyond the treatment zone. Monitoring for injected chemicals and
contaminant beyond the treatment zone, particularly in locations down gradient to and beneath the
treatment zone, can also provide data about whether hydraulic control of fluids has been maintained
during the soil flushing process. Finally, maintaining a log of the water levels at all wells to create
potentiometric surface maps can provide further supporting evidence that proper control over injected
fluids was maintained during flooding operations.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4. EXAMPLE -SURFACTANT FLUSHING FIELD DEMONSTRATION AT U.S. MARINE
CORPS BASE CAMP LEJEUNE
4.1 Camp Lejeune Background and Site Details
In 1999, a surfactant enhanced aquifer remediation (SEAR) demonstration, funded by the Environmental
Security Technology Certification Program (ESTCP), was conducted to remove a chlorinated
hydrocarbon DNAPL present in the subsurface beneath the central dry-cleaning facility (Building 25, Site
88) at U.S. Marine Corps Base Camp Lejeune, North Carolina. The main contaminant was
tetrachloroethylene or PCE, a common dry-cleaning solvent. At this site, groundwater contamination of
the shallow and intermediate aquifers has resulted from the storage and disposal of PCE and Varsol™
dry-cleaning solvents. The latter is a mineral spirit-type solvent. The footprint of the demonstration well
field was 20ftx30ft(6.1mx9.1 m), and the DNAPL contaminated zone targeted for remediation was
the bottom 5 ft (1.5 m) of the shallow aquifer. The total aquifer pore volume treated was approximately
6600 gallons (25.0 m3). By design, the ESTCP SEAR Camp Lejeune demonstration treated only a portion
of the entire DNAPL source area. In addition to the subsurface treatment by SEAR, the ESTCP SEAR
demonstration was the first to incorporate above-ground treatment of the SEAR extraction well effluent
(i.e., groundwater, surfactant, and DNAPL) by pervaporation and micellar-enhanced ultrafiltration
(MEUF) for the objective of surfactant recycle. The objectives of this demonstration were to: 1) validate
in situ surfactant flooding for DNAPL removal; 2) promote the effective use of surfactants for widespread
DNAPL removal; 3) demonstrate that surfactants can be recovered and reused; and 4) show that
surfactant recycle can significantly reduce the overall cost of applying surfactants for subsurface
remediation.
The locations of the three surfactant injection, two hydraulic control, and six extraction wells relative to
Building 25 are shown in Figure 3. Six MLS wells each with three vertical sampling locations in the 16.5
to 20 ft bgs range were positioned within the well field (not shown). Injection and extraction wells were
screened across the bottom portion of the shallow aquifer from approximately 15 to 20 ft (4.6 to 6.1 m)
below ground surface (bgs), which coincided with the depth interval of the DNAPL contaminated zone.
Varsol™, present as an LNAPL in the upper portion of the shallow aquifer (8 to 10 ft bgs) was not
targeted for remediation. However, some Varsol™ was present as a component of the PCE DNAPL,
varying between approximately 2-14 wt% across the test zone, and was removed incidentally with the
PCE DNAPL.
The DNAPL zone at Building 25 was primarily in the shallow surficial aquifer at a depth of
approximately 16-20 ft (5-6 m), and includes an area that extends about 20 ft (6 m) north of the building.
The DNAPL occurs immediately above and within a relatively low-permeability layer of silty sediments
(hereafter referred to as the basal silt layer). The basal silt layer occurs from approximately 18 to 20 ft
(5.5-6 m) below ground surface (bgs) and grades finer with depth from a sandy silt to a clayey silt until
reaching a thick clay layer at about 20 ft (6 m) bgs. Characterization activities associated with the SEAR
demonstration revealed that this fining downward sequence can be roughly divided into three
permeability zones: the upper zone (-16-17.5 ft bgs; 4.9-5.3 m bgs), the middle zone (-17.5-19 ft bgs;
5.3-5.8 m bgs), and the lower zone (-19-20 ft bgs; 5.8-6.1 m bgs). The site conceptual model, or
geosystem, is shown in cross section in Figure 4.
The upper zone is generally characteristic of the overall shallow aquifer, which is primarily composed of
fine to very-fine sand and is the most permeable of the three zones. The hydraulic conductivity (K) of the
upper zone is estimated to be about 5xlO"4 cm/sec (1.4 ft/day). The hydraulic conductivity of the middle
zone, which is composed predominantly of silt, is estimated to be approximately IxlO"4 cm/sec (0.28
ft/day), or about five times less permeable than the upper zone. The lower zone is composed
predominantly of clayey silt, with a hydraulic conductivity that is believed to be approximately 5x10~5
cm/sec (0.14 ft/day) or perhaps even lower, although the permeability of the lower zone is not well
characterized at this time.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4.2 Camp Lejeune Performance Assessment
Soil core samples were obtained prior to SEAR activities to locate DNAPL, to delineate the boundaries of
the DNAPL contamination and to characterize the subsurface hydrogeology. The soil core samples were
preserved in the field with methanol to minimize contaminant losses by volatilization from the soil
samples. Subsequent to the soil coring, a free-phase DNAPL recovery process was implemented. A pre-
SEAR PITT was then conducted during May/June 1998 to measure the volume and relative distribution
of DNAPL present in the test zone before surfactant flooding. The results of this pre-SEAR PITT
indicated that approximately 74-88 gal (280-333 L) of DNAPL were present in the test zone (Duke
Engineering 1999), which was later determined to be an underestimate. Average DNAPL saturations were
found to be highest in the portion of the test zone adjacent to Building 25, at about 4.5% saturation
(expressed as an average DNAPL saturation over the swept pore volume between an interwell pair of
injection and extraction wells).
The SEAR demonstration at Building 25 included multiple phases of field activities that spanned 143
days. The surfactant flood was initiated with an 8-day water flood, followed by a 58-day surfactant
injection period between April 6 and June 3, 1999, a 34 day post-SEAR water flood, 40 day post-SEAR
PITT, and 3 days of post-SEAR soil sampling. Post-SEAR sampling was conducted under continued
water flooding conditions to avoid re-entry of DNAPL from untreated contaminated zones adjacent to the
treated zone. The injected SEAR solution contained 4.0 wt% Alfoterra 145-4-PO sulfate™ surfactant,
16.0 wt% IP A, and -0.17 wt% CaCl2 and was injected at 0.4 gpm (1.5 L/min). Calcium was used as the
sole electrolyte to avoid ion-exchange induced mobilization of soils fines in the subsurface. The total
extraction rate was 1.0 gpm (3.8 L/min). Groundwater samples were collected from all extraction wells
(EX1-EX6) and from three of the six MLSs throughout the demonstration to monitor the recovery of both
PCE and injected chemicals from the treatment zone. Not all of the selected MLS sampling points
produced sufficient sample volumes for analysis due to the fine-grained nature of the soil. A gradient in
DNAPL contamination with distance from the building was inferred by examining the PCE concentration
curves for the six extraction wells. At EX-03 and EX-6, the extraction wells farthest from the building,
PCE concentrations remained low, not exceeding 20 mg/L throughout the entire SEAR demonstration,
most likely indicating that there was little DNAPL in the vicinity of these locations.
A significant increase in the extraction well effluent PCE concentration was observed in several
extraction wells due to surfactant flooding. At extraction well EX1, the effluent PCE concentration
increased from an average of approximately 200 mg/L to about 2,800 mg/L at the peak breakthrough. At
EX4R, the PCE concentration increased from 80 mg/L to approximately 1,000 mg/L at the peak. In
addition to the extraction wells, PCE concentrations were also measured in MLS points located next to
EX1 and EX4R. At MLS-4T (16.5 ft bgs), the PCE concentration at the start of the surfactant flood was 5
mg/L. The effluent PCE concentration was seen to increase rapidly to 10,860 mg/L before declining to
non-detectable concentrations at the end of the post-SEAR PITT. This is an excellent indication that the
surfactant was highly effective in solubilizing and remediating DNAPL in the upper zone in the vicinity
of MLS-4T. Relatively high aqueous PCE concentrations were observed at MLS-1B (18.5 ft bgs) at the
end of the demonstration suggesting that some DNAPL still remained in the zone adjacent to MLS-1B.
The MLS surfactant and IPA concentration data indicate that little surfactant injectate penetrated (i.e.,
swept) the lower-permeability basal silt layer compared to the upper zone. Thus, little or no DNAPL was
removed at these lower depths. This result can be attributed primarily to the preferential flow of surfactant
injectate through the more permeable upper zones and consequential bypassing of the lower zones, and
secondarily to some surfactant sorption and/or biodegradation.
In addition to enhancing the solubility of the DNAPL, the surfactant flood also enhanced the recovery of
free-phase DNAPL as a result of lowering the interfacial tension of the DNAPL. Because of the presence
of a thick aquitard at the site and because of its greater mass removal efficiency, mobilization of DNAPL
during the surfactant flood was desirable and intended by design. A total of 76 gal (288 L) of PCE was
recovered during the surfactant flood and subsequent water flood, of which approximately 32 gal (121 L)
of PCE were recovered as solubilized DNAPL and 44 gal (167 L) as mobilized free-phase DNAPL.
63
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
A table showing the volume of solubilized and free-phase DNAPL recovered per well is provided as
Table 1.
Table 1: Recovery of Solubilized and Mobilized PCE from Camp Lejeune Wells.
Extraction Well
EX1
EX2
EX3
EX4
EX4R
EX5
EX6
RW1
RW2
Other sources
Total
Solubilized PCE Recovered (gal)
19.4
1.9
0.1
NS
9.4
0.9
0.1
NS
NS
0.0
31.8 gal
(120 liters)
Mobilized PCE Recovered (gal)
15.3
8.7
0.0
3.6
5.2
2.6
0.0
2.0
2.0
4.6
44.0 gal
(166 liters)
NS: not sampled, PCE concentration data was only collected at the extraction wells
The post-SEAR PITT was conducted, along with soil core sampling, to measure the volume of DNAPL
remaining in the test zone after the surfactant flood. During the post-SEAR PITT, the unexpected sorption
of an impurity in the surfactant formulation caused interference with the partitioning tracers, making the
post-SEAR PITT data unusable. The sorption of the surfactant impurity caused false detection of DNAPL
as a result of tracer partitioning into the sorbed surfactant impurity. The surfactant manufacturer, Condea
Vista, has tentatively identified the sorbing substance as a byproduct of the manufacturing process and
has developed an alternative synthesis route that avoids the production of this impurity. However, soil
column studies at The University of Texas at Austin indicated that extended water flooding following
injection of the "purified" surfactant is still required to avoid tracer retention when calcium is used as the
sole electrolyte. This indicates the possible formation of a calcium surfactant complex that retards the
partitioning tracers. The change in the background tracer sorption behavior caused by the SEAR process
violated assumption #2 listed in Section 2 for analysis of PITT data.
Due to the difficulties encountered with the accurate interpretation of the post-PITT data, SEAR
performance was ultimately evaluated by examining combinations of the mass recovery of DNAPL at the
extraction wells, and the pre- and post-SEAR soil sampling data. The pre-SEAR soil samples were not
used to generate an initial DNAPL volume estimate because the sampling frequency used was intended to
locate DNAPL, delineate the extent of DNAPL contamination and to identify an appropriate location for
the SEAR well field. Additionally, during the intervening period prior to the surfactant flood a free-phase
DNAPL recovery effort was conducted and there was difficulty in quantifying the amount of free-phase
DNAPL removed. Therefore, any DNAPL volume estimate generated from the pre-SEAR soil samples
would not accurately represent pre-SEAR conditions.
The post-SEAR soil sampling data consisted of 60 soil samples collected at 12 locations over the
contaminated portion of the aquifer, and was used to generate a three-dimensional distribution of the
DNAPL volume remaining in the test zone following the surfactant flood. Continuous cores were
collected from the bottom 3 feet of the aquifer (representing the DNAPL contaminated zone) and then
subdivided into six inch core samples. The lateral distribution of DNAPL indicates that the majority of
the DNAPL that remains in the test zone is located near the building, between wells EX1 and EX4.
DNAPL volume decreases away from the building, in the area between wells EX2 and EX5, and very
little DNAPL is present in the portion of the test zone that is farthest from the building, between wells
EX3 and EX6. The vertical distribution of remaining DNAPL indicates that DNAPL was effectively
removed from the more permeable sediments, generally above about 17.5 ft (5.3 m) bgs, and that DNAPL
64
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
still remains in the lower permeability basal silt layer. These results are not unexpected, given that the
highest pre-SEAR DNAPL saturations were near the building, as well as the expectation that it would be
most difficult to remove DNAPL from the lowest permeability sediments at the site.
A geostatistical analysis of the post-SEAR soil sampling results was used to interpolate the post-SEAR
soil sampling data to generate a DNAPL volume estimate, as well as to assign error bars to the resulting
estimates. Analysis of the post-SEAR soil core data indicated that approximately 5.2±1.6 gal of DNAPL
remain in the zone that was effectively swept by the tracers and surfactant (i.e. the zone above
approximately 17.8 ft bgs). In addition, data analysis from the post-SEAR soil cores indicated that
approximately 23.5±5.5 gal remain in the mid-to-bottom zone that was not effectively penetrated by the
tracers or surfactant (i.e. from 17.8 ft bgs down to the clay aquitard). The initial PITT estimated that the
volume of DNAPL in the test zone before the surfactant flood was approximately 81 ±7 gals (306±26 L).
It was concluded that the total volume of DNAPL present in the test zone before the surfactant flood is
best represented by both the volume of DNAPL measured by the pre-SEAR PITT plus the volume of
DNAPL estimated (from soil core data analysis) for the zone below 17.8 ft bgs, for a total pre-SEAR
DNAPL volume of approximately 105 gal (397 L). Adding the 76 gallon estimate of DNAPL recovered
at the extraction wells to the 29 gallon estimate of DNAPL remaining in the test zone by soil cores also
yields a similar pre-SEAR DNAPL volume of 105 gallons. Thus the surfactant flood recovered
approximately 72% of the DNAPL from the entire demonstration zone, including all zones above the
aquitard (Duke Engineering 2000).
With respect to the efficiency of hydraulic control during the surfactant flood, IPA recoveries were
sufficiently high, approximately 88%, but surfactant recovery was lower, on the order of 78%. The
surfactant data declined much faster compared to the IPA concentrations in the middle and bottom zones
during the late-time period of the test, which suggests surfactant sorption and/or biodegradation.
Potentiometric surface maps of the shallow aquifer generated for several phases of the demonstration
show that hydraulic control of injected fluids was effectively maintained, with the exception of a minor
loss of hydraulic control at HC1 during Phase II of the surfactant flood. This loss was caused by a slightly
exaggerated gradient between injection well INI and HC1 with the higher viscosity surfactant fluids. This
temporary loss of hydraulic control was confirmed by increasing IPA concentrations with time at a
monitoring well (RW03-not shown), peaking on July 27 (Day 112 of the test) at 2,798 mg/L (compare to
IPA injectate concentration = 160,000 mg/L). However, recovery of 88% of the injected IPA by the end
of the demonstration suggests that any loss of hydraulic control was very minor. During the post-SEAR
water flood and post-SEAR PITT, the potentiometric surface maps show that hydraulic containment was
fully established and maintained for the remainder of the demonstration. In support of this, IPA
concentrations at well RW03 dropped to 428 mg/L with the last monitoring sample collected on August
27. Hydraulic control monitoring conducted beneath the test zone (i.e., below the aquitard) showed that
no downward migration of injected chemicals and contaminant occurred during the SEAR demonstration.
4.3 Camp Lejeune - Performance Assessment Lessons Learned
With respect to performance assessment, while considerable data was collected for evaluating pre- and
post-SEAR DNAPL saturations, only a subset of this data was usable. The pre-SEAR PITT provided
valuable baseline DNAPL conditions in the test zone, although later data suggests that, because of the
permeability contrast in the basal silt layer, the initial PITT did not detect a portion of the DNAPL that
was present in the bottom 1-2 ft (0.3-0.6 m) of the shallow aquifer. The pre-SEAR PITT did, however,
accurately detect and measure the volume of DNAPL in the accessible (i.e., higher permeability) zone
above approximately 18 ft (5.5 m) bgs. Regarding the future use of PITTs, the influence of permeability
heterogeneities as well as potential interference by surfactants when calcium is used as the sole electrolyte
should be carefully considered in design. Finally, performance assessment is inherently limited when the
remedial measure treats only a portion of a NAPL contaminated zone due to the potential for reinfiltration
of contamination from untreated zones. Thus, when high quality performance assessment data is essential,
as in this ESTCP technology validation effort, it is necessary to design the remedial technology to treat
the entire source zone.
65
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
5. CONCLUSIONS
Surfactant and co-solvent flushing technologies offer attractive options for NAPL source area treatment.
Soil core analysis and PITTs are the two most likely performance assessment tools. Soil sampling may
provide significant cost savings for small homogeneous sites. Also, when a high degree of vertical
heterogeneity exists, soil sampling may provide confirmation of DNAPL conditions in the lowest
permeability zones. However, PITTs will be more cost effective and provide more defensible
performance assessment for large-scale sites with a moderate degree of heterogeneity. Great care must be
taken in the planning, execution, and analysis of PITTs in order to yield meaningful information.
Although PITTs can be extremely powerful tools, they have limitations, some of which were evidenced
during the Camp Lejeune field demonstration. In practice, the dual use of PITTs and soil core sampling
can yield sufficient performance validation information.
6. ACKNOWLEDGEMENTS
Much of the information regarding the Camp Lejeune field demonstration project was excerpted from the
draft Final Technical Report for the project as well as the Final Report (Duke Engineering 2000). Many
of the general concepts regarding performance assessment for SEAR processes were originally expressed
in a workshop entitled "Surfactant Enhanced Aquifer Remediation (SEAR)" which was presented most
recently on October 15, 2000 in San Antonio, TX. Material for the workshop was prepared by Duke
Engineering and Services (F. Holzmer, H. Meinardus, V. Dwarakanath, J. Londergan), University of
Texas at Austin (G.A. Pope), and U.S. EPA (L. Vane). The workshop was sponsored by the U.S. Navy
and facilitated by Battelle.
7. REFERENCES
1. Battelle and Duke Engineering & Services, "Surfactant-Enhanced Aquifer Remediation (SEAR)
Design Manual," Prepared for Naval Facilities Engineering Service Center (2001).
2. Brown, C.; G.A. Pope, L.M. Abriola, K. Sepehrnoori, "Simulation of surfactant-enhanced aquifer
remediation," Water Resources Research, 30, 2959-2977 (1994).
3. Butler, E.G., K.F. Hayes, "Micellar solubilization of nonaqueous phase liquid contaminants by
nonionic surfactant mixtures: effects of sorption, partitioning, and mixing," Water Research, 32,
1345-1354(1998).
4. Chevalier, L.R., S.J. Masten, R.B. Wallace, D.C. Wiggert, "Experimental investigation of surfactant-
enhanced dissolution of residual NAPL in saturated soil," Ground Water Monitoring and
Remediation, 89-98 (1997).
5. Delshad, M.; G.A. Pope, K Sepehrnoori, "A compositional simulator for modeling surfactant-
enhanced aquifer remediation: 1. Formulation," J. Contaminant Hydrology, 23, 303-327 (1996).
6. Duke Engineering and Services, "DNAPL site characterization using a partitioning interwell tracer
test at Site 88, Marine Corps Base, Camp Lejeune, North Carolina." Report prepared for U.S. Dept.
of the Navy (1999).
7. Duke Engineering and Services, "Surfactant enhanced aquifer remediation demonstration at Site 88,
Marine Corps Base Camp Lejeune, North Carolina," Final report prepared for U.S. Dept. of the Navy
(2000).
8. James, A.I., W.D. Graham, K. Hatfield, P.S.C. Rao, M.D. Annable, "Estimation of spatially variable
residual nonaqueous phase liquid saturations in nonuniform flow fields using partitioning tracer
data," Water Resources Research, 36, 999-1012 (2000).
66
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
9. Jawitz, J.W., R.K. Sillan, M.D. Annable, P.S.C. Rao, K. Warner, "In-situ alcohol flushing of a
DNAPL source zone at a dry cleaner site," Environ. Sci. Technol, 34, 3722-3729 (2000).
10. Jin, M., M. Delshad, V. Dwarakanath, D.C. McKinney, G.A. Pope, K. Sepehrnoori, C.E. Tilburg,
"Partitioning tracer test for detection, estimation, and remediation performance assessment of
subsurface nonaqueous phase liquids," Water Resources Research, 31, 1201-1211 (1995).
11. Mariner, P.E., M. Jin, R.E. Jackson, "An algorithm for the estimation of NAPL saturation and
composition from typical soil chemical analyses," Ground Water Monitoring and Remediation, 122-
129 (spring 1997).
12. Rao, P.S.C., M.D. Annable, H. Kim, "NAPL source zone characterization and remediation
technology performance assessment: recent developments and applications of tracer techniques," J.
Contaminant Hydrology, 45, 63-78 (2000).
13. Rosen, M.J., Surfactants and Interfacial Phenomena; John Wiley & Sons: New York, 1989.
14. Shiau, B.J., D.A. Sabatini, J.H. Harwell, D.Q. Vu, "Microemulsion of mixed chlorinated solvents
using food grade (edible) surfactants," Environ. Sci. Technol., 30, 97-103 (1996).
15. Sillan, R.K., M.D. Annable, P.S.C. Rao, D. Dai, K. Hatfield, W.D. Graham, A.L. Wood, C.G.
Enfield, "Evaluation of in situ cosolvent flushing dynamics using a network of spatially distributed
multilevel samplers," Water Resources Research, 34, 2191-2202 (1998).
16. Wilson, D.J., R.A. Burt, D.S. Hodge, "Mathematical modeling of column and field dense nonaqueous
phase liquid tracer tests," Environmental Monitoring and Assessment, 60, 181-216 (2000).
17. Wise, W.R., D. Dai, E.A. Fitzpatrick, L.W. Evans, P.S.C. Rao, M.D. Annable, "Non-aqueous phase
liquid characterization via partitioning tracer tests: a modified Langmuir relation to describe
partitioning nonlinearities," J. Contaminant Hydrology, 36, 153-165 (1999).
67
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Figure 1: Surfactant solution containing surfactant monomer and micelles.
NAPL
Water
Surfactant
Monomer
Micelle
''NAPL = non-aqueous phase liquid
68
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
Figure 2: Example PITT tracer response curves (Battelle and Duke Engineering 2001).
69
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Figure 3: Site map of SEAR demonstration at U.S. Marine Corps Base Camp Lejeune. Well field
consisted of six extraction wells (EX1-EX6), three surfactant injection wells (IN1-IN3), and two
hydraulic control wells (HC1 and HC2). Building 25 is an operational dry cleaning facility.
400 420 440 460 480 500 520 540 560
Figure 4: Generalized geosystem cross-section of DNAPL zone at Site 88, Building 25,
MCB Camp Lejeune.
Depth
(ft bgs)
O-i
5-
10-
15-
20d
34-
EX01
ML-1
IN01
ML-4
EX04
. ^z'
—
—
15^ ft ! (
—
X
—
—
Packer
', ~^~ —
-
; Castle Hayne Aquifer . - ; I -•;.-;.-;
~+-
Ground
Surface
Varsol
Smear
Zone
DNAPL
Zone
DNAPL
Clayey Silt
Clay Aquitard
Fine Sand and Silt
70
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
8. PRESENTATION VISUALS ~ presented by Leland Vane and S. Laura Yeh
Site-specific Validation of
Surfactant/Co-solvent
Flushing
Leland M. Vane, Ph.D.
U.S. Environmental Protection Agency
&
S. Laura Yeh
U.S. Navy
2001 NATO/CCMS Pilot Study Meeting
> Validation of in situ Remediation Performance
Surfactant Flushing/Flooding
SEAR stands for:
Surfactant Enhanced Aquifer Remediation
• SEAR involves the injection of surfactants
to recover NAPL-contaminants by either
enhanced solubilization or mobilization
due to interfacial tension reduction.
• May result in a single-phase solution or
multi-phase fluid
Surfactant Solution -
Enhanced solubility of NAPL compounds
in micellar solutions - over 100,000 mg/L
ONAPL
• Water
f Surfactant
Monomer
Micelle
'NAPL = non-aqueous phase liquid
Surfactant Flooding (cont.)
Surfactant also reduces interfacial
tension thereby enhancing NAPL
removal through mobilization
^Mobilization requires a competent
capillary barrier (aquitard) to
prevent vertical DNAPL migration
Outline
Overview of Chemical Flooding
Technologies
Performance Assessment (PA)
Issues & Methods
Surfactant flooding PA example:
Camp Lejeune demonstration
Conclusions
Surfactants
Surfactants are surface active agents. They are
molecules composed of two differing parts: a lyophobic
tail and a lyophilic head. This structure leads to the
molecule's interesting behavior.
Surfactant Self-Aggregate
"Micelle"
Range of Properties of
Injected SEAR Fluids
Anionic Surfactant = 1 to 8 wt%
* well above critical micelle concentration
Alcohol = 0 to 16 wt%
• stabilizes surfactant/contaminant
solution
Ca2+ and/or Na+ = 0 to 1750 mg/L
• reduces migration of soil fines
Co-solvent Flushing
> Co-solvents increase the solubility
of NAPL contaminants in a
homogeneous one-phase system.
- Generally consist of alcohols above
50 wt% in aqueous solution
71
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Surfactant or Co-solvent Flushing
Flushing Solution
Injection Well
Solvent
Disposal
Extraction
Well
Clay Aquitard
Methods for Evaluating the Volume
and Distribution of NAPL
for Performance Assessment
Groundwater monitoring
•Soil sampling
• Partitioning interwell tracer test
(PITT)
• Monitor extraction well DNAPL
concentrations (amount removed)
**
PA of Flushing Technologies
by Groundwater Samples
Use to evaluate whether hydraulic
control has been maintained
Use to monitor residual cone, of
injected chemicals following
treatment
* Surfactant, co-solvent if used and
contaminant
NOT use to assess efficiency of
DNAPL removal.
Soil Sampling Methods
Direct push
Geoprobe® with plastic tube liners
Thinqs to avoid
-Wash rigs (lots of water flooding)
-Air rigs (lotsofSVE)
Thinqs to do (EPA Method 5035)
r Use in-field preservation (methanol)
**
as
General Issues for Performance
Assessment (PA) of DNAPL Sites
DNAPLs tend to be found in regions
of low permeability
The typical DNAPL site has:
• Heterogeneities in permeability
• Variable DNAPL distribution
• Since DNAPL flows with gravity,
data on the depth to aquitard should
be collected.
PA by Ground water Samples
Assumption: A unique relationship
concentrMoJ&(lta^M^tering well)
and the masS ot wluflre^rNAPL in
adjacent portions of the aquifer
Because of mass transfer
limitations, groundwater sampling
is an inadequate method for
PA of a NAPL remedial action.
PA by Soil Sampling
Continuous Soil Cores Sampled With Field Preservation
Soil Sampling Methods (cont.)
- Continuous sampling throughout the
zone of interest:
• Get samples from critical zones
* $$ savings if you do not need upper
zone sampled
72
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Soil Sampling Limited by
Representative Elementary Volume (REV)
The Accuracy of Soil Samples
for Remedial Design
• Range of R EV for NAPL i n soil =10-10" cm3
• Volume of typical soil sample = 30-102 cm
NAPLANAL* Calculates:
*-NAPL saturation
'•NAPL composition
VOC concentrations in each phase
*NAPL estimation computer program developed by
Duke Engineering and Services
**
Geostatistical tools (Kriging) Useful
for Creating Picture of NAPL at Site
*-
•Interpolation method for determining
the average DNAPL volume based on
a set of soil samples
•Calculate the error associated with a
particular estimate
PA by PITTs
PITTs provide measurements on a
meaningful scale
• address REV issue
• can measure DNAPL in the entire
treatment volume swept by tracers
PITT results and error can be
quantified
t.
Issues for PA by Soil Sampling
r Is the sample representative of the area
it is selected to represent (REV)?
*• Has all of the NAPL present been
recovered from each sample?
r Have soil samples been recovered from
all parts of the targeted NAPL zone (i.e.,
from both high and low permeability
zones)?
NAPLANAL Data Needs
*-
MHUI
Field Soil Samples
r Total concentrations
for each component
•• Volumetric water
content
r Soil porosity
'fee
DATABASE
r «„. for each
component
•- KH for each
component
r Molecular weight of
each component
r Densities
• Soil, water, air,
NAPL
<§z
Partitioning Interwell Tracer Tests (PITTs)
' Conservative and partitioning tracers are
injected and monitored at extraction
wells/intermediate locations
•Well-suited for flush ing-type remediation
assessment
• Over 40 PITTs conducted to date
• Developed for DNAPL site
characterization by Dr. Gary Pope at UT-
Austin and Dr. Dick Jackson at Duke
Engineering & Services
PITT Assumptions
<• Multiple tracers with a wide range of Ks used
/•Tracer partition coefficients (K) accurate
r Reversible sorption to sedimentary organic
matter quantified
^Tracers penetrate all parts of the NAPL zone:
• Free-phase NAPL zones
• Low Intrinsic permeability or relative
permeability zones
/-Sufficient equilibration time provided to
assess tracer signals from all parts of NAPL
zone
73
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
PITT Weaknesses
(violations of assumptions)
'-Pooled or free-phase DNAPL
• underestimate of DNAPL saturation
if free-phase is not removed
/'High soil heterogeneity -
• results in poor sweep of low
permeability zones
• mobility control may correct for this
PITT Weaknesses (cont.)
• Affected by spatial variation in NAPL
composition and naturally occurring
organic matter (measured as fw)
• K must be measured for different NAPL
compositions and foc
• inaccuracies in K estimation may result
• For SEAR applications, surfactant
complexation with clay fines may be
a concern
1000
0.1
/••-••-.,
NAPL
Present
;' Note: Tracer
Separation
• 1-Pentand(K=l9)
2-Bh>l-1-biitana (K=125)
• 1-Hep«nol(K=uo,5)
2 3 4
Titm.Days
PITTs: Performance Validation
Difference in DNAPL volume estimates
obtained from pre- and post-PITTs
indicate level of removal in flushed
zone
• Multi-level sampling (MLS) during
remediation and PITTs can yield
assessment of vertical variations in
performance effectiveness
Post-SEAR PITT
1 Tracer Concentration,
mg/L
NAPL
X"""4"-- •-.., Removi
/ '.«.*..
•
Note:
1Jtop»»l(K=5.1)
Separation . I-H«X«>OI IK-M.?>
»d
1123456
Time, Days
t A
NflVIAC ^$2.
Issues for PA of in situ
flooding technologies
Flushing/PITT fluids will tend to flow through
high permeability zones
• Low permeability zones are most susceptible to
residual contamination
• Recovery of injected chemicals never 100%
• Post-treatment monitoring may be required
• SEAR not intended to reduce GW cone, to
MCLs
• DNAPL mass estimates necessary to gauge
performance
Example Site
^U.S. Marine Corps Base Camp
Lejeune
• Soil contaminated with dry cleaning
solvent (PCE) - Site 88
wnru:
WELCOME TO
£ CORPS
CAMP LEJEUNE
CENTRAL
WClUNtRS
Surfactant Enhanced Aquifer
Remediation with Surfactant
Regeneration/Reuse
Lead Organizations:
- Naval Facilities Engineering Service Center
(NFESC), Port Hueneme, CA
• U.S. EPA National Risk Management Research
Laboratory (NRMRL), Cincinnati, OH and Ada, OK
Collaborators:
- University of Texas, Austin, TX
- University of Oklahoma, Norman, OK
- Duke Engineering & Services, Austin, TX
Mmitc as
74
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Camp Lejeune Demo Zone
- Size of test zone - 20' x 30' (6.1 m x 9.1 m)
• Test zone = approx. 25% of DNAPL zone
Depth to aquitard -18-20 ft bgs (5.5-6,1 m)
• Soil type - fine to very fine sands and silts
• Hydraulic conductivity = 5x10^ to 5x10-5
cm/s
Primary Contaminant - PCE
• Initial DNAPL volume - 105 gal (-397 L)
• Surfactant injected in bottom 5 ft of aquifer
Camp Lejeune Site Map
3 Injection wells, 2 hydraulic control wells, 6 extraction wells
Geosystem Cross Section of
MCB Camp Lejeune DNAPL Zone
ML = Multi-level sampler
Schedule of Camp Lejeune
Flooding Activities in 1999
Dates Activity Duration
Mar29-Apr6 Pre SEAR Water Flood 8 days
Apr 6-May 14 Surfactant Flood I (fresh) 37 days
May 14-Jun 3 Surfactant Flood lljrecycled) 21 days
Jun 3-July 7 Post-SEAR Water Flood 34 days
July7-Aug16 Post-SEAR PITT (PITT2) 40 days
Aug 16-19 Post-SEAR soil sampling 3 days
(water flooding continued)
Total duration of flooding: 143 days
Camp Lejeune SEAR Well Field
<"
imnc
Potentiometric Surface - Hydraulic Control
I i t. T* S I \ Mrtrlh UU
Camp Lejeune
Performance Assessment and
Monitoring Methods
'Extraction fluid monitoring
-MLS Monitoring during SEAR
flood
•Pre/Post Partitioning interwell
tracer tests (PITT)
Pre/Post Soil sampling
Analysis of Extracted
Flushing Solution
-Estimate mass of contaminants
recovered
•Estimate mass of surfactant recovered
•Determine if hydraulic control is
adequate
-Multi-level samplers monitor delivery
of flushing agents to all vertical zones
75
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
SEAR Effluent - Evidence of
Contaminant Removal
Pearl Harbor Samples
L Estimated DNAPL Recovery
Camp Lejeune Extraction Well Data |
Closest''
to
Building^
A
Extraction
Well
| fXOI
EX02
EX03
EXM
I LSMR
E.X05
EX04
RIV01
RW02
i:tl«r suurus.
Total
Solubilizcd PCE Mobilized PCE
Recovered (g3l) Recovered t;:;il j
19.4 I5J
1.9
O.t
NS
8.7
0.0
3.6
y 4 ^ :
0.9 2.6
0.1
IS
MS
0.0
31.8
0.0
20
IS>
46
44.0
NS: not sampled, PCE dau tuny effected at me exlractlon wels
£3^ Overall PCE Recovered -76 gal (288 L) R^
rSEAR Flood Multi-Level Sampler Data - 1
MLS-4B (18.5 ft bgs) - near aquitard
Lt
Sv
&
w and Variable IPA Concentrations Indicate Poor
veep of Lower Contaminated Region by SEAR Fluid
Concentration, wttt
i e . » i
*
••
•
.. :
•
•
•
• B
• Alcohol
3 SM i'29 &26 7TZI 8(21.
Dale(*n1999)
S4eS*.f*S.:*r»LS|WrW I.C jj^Z
Camp Lejeune PITT1 Results
**
imnr:
Ex.
Well
EX01
EX02
EX03
EX04
EX05
EX06
Total
Tracer Swept
Recovery Volume
(%) (gal)
13
17
10
14
17
14
85
790
1030
540
790
890
740
4780
_.,._. DNAPL
DNAPL
, „, , Volume
safn<%> (gal)
3.9
0.5
0.4
4.5
1.0
0.4
31
5
2
36
10
3
1.8 87
18.1 m3 329 L
jfe
Extraction Well PCE Data
10000
f 1000
| 100
1
t -
i
MWM:
•<*
" ,*
Surfattanl Fl
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
PITT Lessons learned
" Mobility control measures needed to
minimize short-circuiting through
high permeability zones
r Experiments to test for sorbing
impurities in surfactants should be
conducted
Estimated Costs (US$) for
Camp Lejeune PITT
-Low Permeability Site, 40 days
• Pre/post-PITT, 111 yd3: -$127,000 each
• Pre-PITT, 463 yd3: $182,100
• Post-PITT, 463 yd3: $164,500
High Perm. Site, 23 days
• Pre-PITT, 617 yd3: $74,900
• Post-PITT, 617 yd3: $71,200
Camp Lejeune
Post-SEAR Soil Sampling
12 locations, 60 samples for
DNAPL volume estimate
• Continuous cores in bottom 3 ft
(1m) -just aboveaquitard
• 6 inch core samples
• 1 borehole per 6,6 m2
I Soil Sampling PA
DNAPL Volume Error Sources
*
KM
Parnmetor Contributor C'y % Error
Residual
Saturation
SN
IJoinain
volume
VT
*
-JXNAPL,
V Glume v?s;
organic carbon
Porosity
GC analysis
number of
bonngs
sampling
mldrvaT
Interpolation
Porosity
58%
9^b
20%
6%
5%
14%
9%
23%
16%
9%
29%
L <*
H W^
unite
Interpretation of Post-SEAR
Soil Core Data
" 5,2 +/• 1,6 gal DNAPL remain in zone
effectively swept by tracers and
surfactant (i.e. above -17.8 ft bgs)
^-23.5 +/- 5.5 gal DNAPL remain in mid-to-
bottom zone that was not effectively
penetrated by tracers or surfactant (i.e.
from 17.8 ft bgs down to aquitard)
Interpretation of Post-SEAR
Soil Core Data (cont.)
Surfactant flood recovered -70% of the
DNAPL from the entire zone
• Mass recovery of DNAPL from extraction
wells: -76 gal (288 L)
• Initial DNAPL estimate by PITT: 81:7 gallons
• Final DNAPL estimate by soil sampling:
29 ± 9 gallons (23.5 gal in lower zones)
• "Amalgamated" initial DNAPL estimate:
105 ± 12 gallons (397145 L)
invite
Interpretation of Post-SEAR
Soil Core Data
Surfactant flood recovered between
92% to 96% of DNAPL present in the
pore volume that was swept by the
pre-SEAR PITT (i.e. above 17.8 ft bgs)
• Little to no DNAPL recovered from
zones below 17.8 ft bgs
SEAR Effectiveness at Camp
Lejeune, Site 88
K1
K2
K3
Diffusion from low-perm zone
K1 > K2 > K3
Aqueous dissolution should be significantly reduced
since most of the accessible DNAPL (from K1 & K2 zones)
has been removed from the dominant ground-water
flow paths.
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Performance Verification of In Situ Remediation
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Conclusions on PA Methods for
Quantifying NAPL Volume
' Groundwater sampling not valid for
even semi-quantitative assessment
Soil sampling is semi-quantitative:
• REV limitations
• potential loss of contaminants
• uncertainty is not quantifiable
r PITTs are more complex, but when
properly designed and implemented,
provide a means of accurately and
quantitatively measuring NAPL
k volumes with quantifiable uncertainty.
Conclusions for Flushing Tech. PA
Multiple PA methods needed for
accurate results
• Soil sampling costly for large treatment
volumes.
* PITTs may not sweep low permeability
zones when high perm contrasts exist.
• Multi-level samplers can identify which
zones have been swept by surfactants and
the relative removal of DNAPL with depth
- PA must account for heterogeneities
and spatial distribution of DNAPL
Acknowledgments
Duke Engineering and Services
• Fred Holzmer et at.
University of Texas at Austin
• Prof. Gary Pope et a/.
Battelle Memorial Institute
• Neeraj Gupta et al.
invite
78
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF IN SITU BIOREMEDIATION
Frank Volkering1
1. INTRODUCTION
Biological remediation strategies such as in-situ bioremediation, biobarriers and monitored natural
attenuation require detailed knowledge of groundwater processes, and especially of biodegradation
processes. The information obtained via traditional lines of evidence is not always conclusive or
sufficient. Table 1 provides an overview of the traditional characterization methods.
Table 1: Strengths and weaknesses of traditional characterization methods.
Method
Pollutant concentration
Degradation intermediates
Mineralization products
Geochemical
characterization
Microcosm studies
In situ experiments
Strength
specific, quantitative
conclusive, specific, quantitative
conclusive, quantitative
important process parameters
conclusive, specific, semi-
quantitative
conclusive, quantitative
Weakness
inconclusive
not for all pollutants
not specific
not specific, qualitative
lengthy, expensive
lengthy, expensive
Biochemical techniques, such as DNA/RNA analysis may be used to obtain conclusive and specific
evidence for biodegradation, but the evidence is mainly qualitative and as yet only applicable for a limited
number of pollutants.
This paper presents a new line of evidence for bioremediation, based on the natural stable isotope
composition of organic pollutants. Isotope analysis gives us a view into the pollutant molecules and offers
conclusive, pollutant-specific, and possibly even quantitative information on biodegradation processes.
2. THEORY
Isotopes are elements with the same atomic number, but with a different atomic weight. Most elements on
earth consist of two or more stable isotopes, as can be seen for the elements occurring in the most
common organic pollutants in Table 1 below.
Table 2: Elements of the most common organic pollutants and their isotopes.
Element
hydrogen (H)
carbon (C)
nitrogen (N)
oxygen (O)
chlorine (Cl)
Common isotope
isotope %
'H 99.985
12C 98.89
14N 99.63
16O 99.759
35C1 75.53
Other stable isotopes
isotope %
2H 0.015
13C 1.11
15N 0.37
17O 0.037
18O 0.204
37C1 24.47
1 Frank Volkering, Tauw bv, P.O. Box 133, Deventer, The Netherlands, fvo@tauw.nl
79
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Performance Verification of In Situ Remediation
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For analytical reasons, stable isotope concentrations are expressed using the 5-notation, relating the
isotope ratio of a sample to that of a standard reference material. For 13C, the standard material is Vienna
PeeDee Belemnite (VPDB), a marine carbonate. The 5 for 13C is defined as:
sample
-1 x1000
i VPDB)
Due to difference in mass and size, stable isotopes of one element behave slightly different in many
physical, chemical and biological processes. In most biodegradation processes, the lightest isotope is
degraded preferentially. This causes a small, but usually significant change in the isotope composition of
the residual pollutant. This so-called isotopic fractionation can be described with the Rayleigh equation:
in which R is the isotope ratio (e.g. 13C/12C), RO is the initial isotope ratio, f is the fraction residual
substrate, and a is the fractionation factor. Figure 1 gives a theoretical example of the changes in isotopic
composition (expressed as 5) of the parent compound (the pollutant) and the reaction product during a
fractionating reaction.
Figure 1: Theoretical change in the stable isotope composition of reactant (parent compound) and
reaction product during a fractionating reaction.
20
reaction
15-
10-
"3
50 = 0
a = 0.995
residual fraction f (-)
3. COMPOUND-SPECIFIC ISOTOPE ANALYSIS OF POLLUTANTS
Combination of a chromatrographical pretreatment to separate different compounds with continuous flow
isotope ratio mass spectrometry makes it possible to measure the stable isotope composition of individual
organic components in a mixture. This so-called compound-specific stable isotope analysis (CSIA) allows
us to determine the isotopic composition of a single organic pollutant in groundwater. For carbon, this
technique has already been applied since 1997. Recently, CSIA of deuterium (2H) has also become
available. In the near future, CSIA is expected to become applicable to other relevant isotopes.
CSIA enables us to follow the isotopic composition of a pollutant during the course of biodegradation
processes (parent compound in Figure 1). Laboratory studies have shown a strong isotopic fractionation
of 13C to occur during reductive and oxidative degradation of many chlorinated aliphatic hydrocarbons
80
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
(e.g. PCE, TCE, DCE, VC, TCA, and DCA). For the degradation of aromatic hydrocarbons (BTEX,
phenols) and MTBE, a small but significant 13C-fractionation has been observed. Fractionation of 2H has
only been measured in a limited number of studies, but promises to offer very powerful evidence for
biodegradation.
A literature example of the 13C- fractionation during the reductive dechlorination of trichloroethylene
(TCE) and the oxidation of 1,2 dichloroethane (DCA) is given in Figure 2 below. Table 2 presents a
qualitative overview of the fractionation during different degradation processes, based on fractionation
factors reported in the literature (laboratory studies).
Figure 2: Fractionating effect of trichloroethene (TCE) reduction and 1,2 dichloroethane (DCA)
oxidation. TCE data from Sherwood-Lollar, et al, 1999; DCA data from Hunkeler and Aravena, 2000.
6
o
£
4
u
o
u
u
0,7 0,6 0,5 0,4 0,3
residual fraction TCE / DCA (-)
0,2
0,1
Table 3: Qualitative data on fractionation during different degradation processes.
Pollutant
Isotopic fractionation
Hvdroaen
Carbon 1 Chlorine
chlorinated aliphatic hydrocarbons anaerobic
tetrachloroethylene
trichloroethylene
cis-dichloroethylene
vinyl chloride
n.a.
oooo
?
?
ooo
ooo
ooo
oooo
00
oo
?
?
chlorinated aliphatic hydrocarbons aerobic
cis-dichloroethylene
dichloromethane
?
?
oooo
oooo
?
00
aromatic hydrocarbons anaerobic
benzene
toluene
ethylbenzene
xylenes
000
ooo
ooo
?
0
o
o
0
n.a.
n.a.
n.a.
n.a.
miscellaneous hydrocarbons
MTBE (aerobic)
ooo
oo
n.a.
NOTES:
o = limited fractionation
ooo = strong fractionation
n.a. = not applicable
oo = fractionation
oooo = very strong fractionation
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4. FIELD APPLICATION
To be able to use isotopic fractionation as evidence for biodegradation, it essential to exclude
fractionation by other processes. Of the processes occurring in groundwater, only volatilization and
chemical transformation may have a significant fractionating effect. Other processes, such as dissolution,
transport of solute molecules and sorption, do not affect the isotopic composition of pollutants
significantly. Unexpectedly, volatilization seems to reduce the 13C-content of volatile organic compounds
and thus has a fractionating effect contrary to that of biodegradation. Therefore, isotopic enrichment of
the residual pollutant provides conclusive evidence for in situ (bio)degradation.
CSIA can be applied in two different strategies. In the first strategy, CSIA is performed on contaminated
groundwater samples along the source-plume path from one sampling round. Assuming degradation to
proceed with transport of pollutant from the source zone, a sort of fractionation curve as presented in
Figure 1 can be constructed by plotting the isotopic composition against the pollutant concentration. It
should be noted that this is not a true fractionation curve, since the disappearance of pollutant will at least
be partly caused by dilution. An alternative way of presenting the data is to plot the isotopic composition
against the distance from the source zone. Using the source-plume strategy, it should theoretically be
possible to use a known fractionation factor to calculate the extent of biodegradation that has occurred. As
yet, however, our knowledge of isotopic fractionation is too limited to allow translation of fractionation
factors obtained in laboratory experiments to the field situation.
The second strategy in which CSIA can be used is to include the analysis in a monitoring series. For
analytical reasons, comparison of 5-values is best done within one measurement series. This implies that
time-series of isotopic data from single monitoring wells are likely to have limited value. However, the
comparison of isotopic trends within different sampling rounds can be very useful and can be used to
provide evidence for ongoing biodegradation and to correct for seasonal fluctuations in pollutant
concentrations.
4.1 Fractionation of Chlorinated Aliphatic Hydrocarbons
As can bee seen in Table 3, the reductive and oxidative degradation of chlorinated hydrocarbons have a
strong fractionating effect on both 13C and 2H. Therefore, CSIA is a good method for obtaining evidence
for these degradation processes. However, the formation of less chlorinated intermediates during
reductive dechlorination provides straightforward and conclusive evidence for degradation, diminishing
the need for a more advanced technique such as isotope analysis. In complex cases with several source
zones or with several different CAH present, additional evidence may be necessary. Recent field studies
have shown CSIA of 13C in PCE and TCE to be an effective characterization method (Sherwood Lollar et
al. 2001).
4.2 Fractionation of Aromatic Hydrocarbons
With traditional techniques, it is very hard to obtain evidence for the (an)aerobic degradation of
individual aromatic hydrocarbons in a mixture. Therefore, CSIA offers unique possibilities for aromatic
hydrocarbons.
The source-plume strategy described above was applied in a recent research project at the site of Dow
Benelux NV, Terneuzen, and The Netherlands. In this study, CSIA of both 13C and 2H have been used to
investigate the natural attenuation of a contamination with benzene and ethylbenzene in an anaerobic
aquifer (Mancini et al., 2001). From previous groundwater investigations, including a geochemical
groundwater characterization, degradation of ethylbenzene was concluded to occur. Degradation of
benzene, however, could not be ascertained. The results of the CSIA study are shown in the Figures 3 and
4 below.
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Figure 3: Stable isotope composition (13C, 2H) of ethylbenzene in samples from the source zone (• ) and
the contaminant plume (+).
-28,5
5 H ethylbrenzne (%o
20
10
0
-10
-20
-30
-40
ethylbenzene
* source
* plume
/
X
1Z
T J
V I
x
X
X
X
X
X
X
X
X
/
" ,TT
-28
-27,5
-27
-26,5
-26
-25,5
513C ethylbenzene (%o VPDB)
Figure 4: Stable isotope composition (13C, 2H) of benzene in samples from the source zone (I
contaminant plume (+).
I) and the
=
N
1
70 •
65 •
60
55 •
50 •
45 •
40 •
benzene
* source H
*plume
i 1
L
f
i —
-29,5 -29 -28,5 -28 -27,5 -27 -26,5
513C benzene (%o VPDB)
For both ethylbenzene and benzene, the data showed a small enrichment of 13C (l-2%o) in samples from
the plume compared to samples from the source zone. However, for the isotopic shift to become
significant, a concentration reduction of approximately 80-90% was required. This need for samples in
which degradation is in an advanced stage limits the applicability of 13C CSIA. Therefore, the study also
included CSIA of 2H in ethylbenzene and benzene. The 2H results showed a much stronger fractionating
effect (fractionation of up to 60%o for ethylbenzene and up to 28%o for benzene) and provided conclusive
evidence for the biodegradation of benzene, even in downgradient samples that still have relatively high
pollutant concentrations. To our knowledge this is the first time field evidence for anaerobic degradation
of benzene is obtained without the use of microcosm studies.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
5. CONCLUSIONS
CSIA presents a new and very promising line of evidence for in-situ biodegradation. It has several
advantages over existing methods in terms of specificity, conclusiveness, and cost-effectiveness. At
present, CSIA is especially useful for degradation processes for which no other conclusive lines of
evidence exist, such as the anaerobic degradation of benzene in a BTEX pollution. For other degradation
processes, such as the reductive dechlorination of CAH, CSIA may be useful in complex situations or as
an independent alternative line of evidence.
The practical application of CSIA in field studies is rather straightforward. Standard techniques can be
used for groundwater sampling,, and after a simple conservation step, samples can be sent to a specialized
isotope laboratory. The most crucial steps in the process are the selection of the samples and the
interpretation of the results.
CSIA still has some drawbacks, such as the limited number of laboratories able to perform the analyses,
the high detection limits, the rather long turnover times and the relatively high analysis costs (especially
for elements other than carbon) However, compound-specific isotope analysis is a rapidly developing
technique, and it is expected that most of these drawbacks will be overcome soon.
6. AKNOWLEDGEMENTS
The results presented here are obtained in a research project that was partly financed by the Dutch Soil
Research Program (8KB), by Dow Benelux nv, and by the Dutch provinces of Drenthe, Gelderland, and
Noord-Brabant
Compound-specific isotope analyses of 13C and 2H for the study a the site of Dow Benelux NV,
Terneuzen have been performed by Silvia Mancini form the Stable Isotope Laboratory of the University
of Toronto.
7. REFERENCES
1. Hunkeler D. Aravena R. (2000). Evidence of substantial carbon isotope fractionation among
substrate, inorganic carbon, and biomass during aerobic mineralization of 1,2-dichloroethane by
Xanthobacter autotrophicus. Applied & Environmental Microbiology 66(11):4870-4876.
2. Mancini S.A., G. Lacrampe-Coulome, H Jonker, B.M. van Breukelen, J. Groen, F. Volkering and B.
Sherwood Lollar (2001). Hydrogen Isotope Enrichment: A Definitive Indicator of Biodegradation at a
Petroleum Hydrocarbon Contaminated Field Site. Manuscript submitted to Environmental Science
and Technology.
3. Sherwood Lollar B., G.F. Slater, J. Ahad, B. Sleep, J. Spivack, M. Brennan, P. MacKenzie (1999).
Contrasting carbon isotope fractionation during biodegradation of trichloroethylene and toluene:
Implications for intrinsic bioremediation. Organic Geochemistry 30 813-8209.
4. Sherwood Lollar B., Slater GF. Sleep B. Witt M. Klecka GM. Harkness M. Spivack J. (2001). Stable
carbon isotope evidence for intrinsic bioremediation of tetrachloroethene and trichloroethene at area
6, Dover Air Force Base. Environmental Science & Technology. 35(2):261-269.
5. Stehmeier L.G., RHornett, L Cooke, M.M Francis (2001). One year of monitoring natural attenuation
in shallow groundwater. Paper presented at the 2001 International Symposium on In Situ and On Site
Bioremediation, San Diego, June 2001.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
8. PRESENTATION VISUALS -presented by Frank Volkering
fCCMS spesial session on validation of
MI remediation
Compoundspecific stable
isotope analysis
a new line of evidence for in situ
bioremediation
Frank Volkering
Evidence for bioremediation (2)
Traditional validation techniques
- Decrease of pollutant concentration
• not conclusive (disappearance * degra"
- Formation of intermediates and
degradation products
• not for all contaminants
- Geochemical groundwater characterization
• not conclusive, not specific, qualitative
- Microcosm or mesocosm mmfirimfinta
• not conclusive, V
Evidence for bioremedation (3)
New techniques
;hemlcal characterization
ncluslve evidence lor degradation
miied appiicabiiily
i 1,-uitaltve technique
• often sedinienl samples required
- Hydrogen measurements
• process parameter for redurii»»
- Compound;
Tauw
s and isotopes
: nucleus
- number of protons defines the element
bar of neutrons defines the isotope
element Is carbon
— isotope = carbon-12 or "C
n-13 or 13C
Two types of isotopes
2 Stable isotopes
carbon-13)
- most elements consist of 2 or more
isolopes (H. C, N. 0. S. Cl)
- behave differently in several processes
85
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Fractionation of residual pollutant
• preferential degradation lighter isotope ^
residual pollutant enriched in heavy isotope
• applicable for
- chlorinated aliphatic hydrocarbons
-aromatic hydrocarbons (BTEX)
-MTBE
86
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
o strategies
. Jong source - plume path
- evidence for biodegradation
ratification of biodegradation (halflives?)
Including CSIA in monitoring
- evidence for ongoing biodegradation
-correction for concentration fluctuations
.iic evidence for the
anaerobic degradation of
benzene and ethylbenzene
Results of a field study at the site of Dow
Benelux. Temeuzen
ite description
Contamination with benzene and
ethylbenzene
Two source zones
Plume length benzene >160 m
Anaerobic groundwater
(sulfate reducing / methanogenic)
Cross section methane
Conclusions "standard" NA
study
"cient evidence for anaerobic
(methanogenic) degradation of
ethylbenzene I
• Anaerobic degradation of benzene ???
• Additional information required
^ compoundspecific 13C analysis
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Conclusions 13C study
^^H
mall, but significant fractionation of
enzene and ethylbenzene ^
iodegradation is occurring
large extent of degradation (80-
disappearance) required to obtai
conclusive evidence
^ compoundspecific ?H measurements
Strong fractionation of 2H in benzene and
ethylbenzene + conformation of
biodegradation
Significant fractionation at lesser extent of
>todegradation (± 50% disappearance)
High detection limit (5000 ppb) limits
application, technique under development
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Practical aspects of CSIA
Groundwater sampling: standard techniques
Analysis: specialized laboratories
isotope
costs (US$)
new
not standard
Acknowledgements
ik Jonker. Boris van Breukelen, Koos
roen (Vrije Universitieit Amsterdam)
Silvia Mancini, Barbara Sherwood-Lollar
(University of Toronto)
rested in isotopes?
Attend the symposium
"Natural isotope analysis in soil
and groundwater poiluti
research"
October 10.,
For everything you always wanted to know
about isotopes and more:
$tate-of-the-art
on isotope analysis
(available soon)
Chlorinated hydrocarbons
strong fractionation of 13C and 2H
applicable for reductive dechlorination
and oxidative degradation
suited as second line of evidence
besides intermediate formation
Tauw
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF IN SITU CHEMICAL OXIDATION
Eric Hood1, Robert L. Siegrist2 and Neil Thomson3
1. INTRODUCTION
During the 1990's, in situ chemical oxidation (ISCO) emerged as a promising method for remediation of
contaminated sites. As a site remediation technology, the goal of ISCO has been to destroy target organic
chemicals present in soil and groundwater systems and thereby reduce the mass, mobility, and/or toxicity
of contamination. Fundamental and applied laboratory research has elucidated many aspects of the
reaction stoichiometry, degradation pathways, and kinetics for common organic chemicals in aqueous
systems as well as the effects of temperature, pH, and matrix composition. Laboratory research has also
explored the transport processes affecting oxidant delivery and dispersal in a porous medium like soil or
aquifer sediments. Pilot-scale demonstrations and full-scale applications have attempted in situ treatment
of aqueous and sorbed phase levels of organic contaminants, and to a lesser degree, dense nonaqueous
phase liquids (DNAPLs). Oxidant delivery and distribution in the subsurface has been accomplished
using injection probes, deep soil mixing, hydraulic fracturing, and vertical or horizontal groundwater
wells. The literature now contains numerous research articles and technical reports, as well as several
recent guidance documents that describe ISCO using hydrogen peroxide (or Fenton's reagent), ozone, and
permanganate for treatment of organics in soil and ground water (e.g., USEPA 1998b, ESTCP 1999, Yin
and Allen 1999, Siegrist et al. 2000, Siegrist et al. 2001).
Chlorinated solvents (as DNAPLs) are frequently released into the subsurface environment from
industrial sources through both intentional disposal, and accidental leaks and spills. The United States
Environmental Protection Agency (USEPA) reported in 1997 that DNAPLs may be present at up to 60%
of the Superfund National Priorities List (NPL) sites (USEPA 1997). Of the 622 NPL sites reported in
1996, the chlorinated solvents trichloroethene (TCE) and perchloroethene (PCE) were detected in
groundwater at 336 and 167 of these sites, respectively (USEPA 1998a). TCE and PCE are of particular
concern because of the potential risks that they pose to human health; accordingly, the concentrations of
these compounds have stringent regulatory levels.
At many sites, attempts to manage groundwater contamination associated with the presence of DNAPLs
have met with limited success. The depth and areal distribution of DNAPLs often precludes any attempts
at excavation while the effectiveness of pump-and-treat is limited by the low solubility of these
contaminants, the weakness of dispersive mixing processes, and mass transfer limitations from the
DNAPL into the dissolved phase. Increasingly, source removal technologies such as in situ chemical
oxidation are being aggressively employed to remove DNAPL mass and/or reduce the concentration of
the target contaminants below regulatory criteria with little knowledge of the expected performance of
this technology. Only a limited number of controlled field trials that provide an indication of ISCO
performance at DNAPL sites have been reported in the literature.
Several oxidizing agents are commonly used for ISCO including Fenton's reagent (Fe2+/FL,O2), and
permanganate (MnO4) (USEPA 1998b, Gates-Anderson et al. 2001, Siegrist et al. 2001). Fenton's
reagent and permanganate can rapidly mineralize both TCE and PCE to inorganic products including
chloride and carbon dioxide. The rapid degradation reactions enhance the removal of the DNAPL by
increasing the concentration gradient that drives the rate of mass transfer. However, this technology is
limited by the ability to advectively deliver the active oxidant (hydroxyl radicals in the case of Fenton's
reagent) to the DNAPL in the subsurface. Oxidant delivery is complicated by both geologic
heterogeneity and secondary oxidation reactions between the reagent and the reduced organic and
inorganic phases within the natural aquifer matrix.
1 GeoSyntec Consultants, Guelph, Ontario, Canada N1G 5G3. Phone: 519-822-2230 Telefax: 519-822-3151 Email:
ehoodiSgeosvntec.com
2 Colorado School of Mines, Golden, Colorado, USA. Email: siegrist@mines.edu
3 University of Waterloo, Waterloo, Ontario, Canada.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
A number of factors can limit DNAPL removal by ISCO. While the DNAPL mass present in regions of
the aquifer where oxidant delivery is dominated by advection may be readily removed, the rate of mass
transfer from DNAPL mass in stagnant zones is limited by diffusion of the contaminant and oxidant
through the water surrounding the DNAPL. Oxidant delivery though diffusion and the degradation of
TCE in low permeability zones has been demonstrated (Siegrist et al. 1999, Struse et al. 2001). However,
oxidant delivery by diffusive transport alone is less likely to result in a significant mass transfer and
degradation enhancement (Hood and Thomson 2000).
2. REMEDIATION EFFECTIVENESS
As observed in a controlled field trial evaluating the performance of ISCO using permanganate (Schnarr
et al. 1998) the most optimistic result is complete DNAPL removal. Since the DNAPL resulting in the
formation of a groundwater plume is removed, the concentration of the contaminant in groundwater will
decrease over time and eventually should reach background levels.
The most likely outcome of an ISCO treatment approach at a DNAPL site, is partial DNAPL mass
removal accompanied by a reduction in the average concentration of DNAPL organics in the groundwater
plume. In the short-term, residual oxidant (e.g., permanganate) in the treatment zone following the period
of active oxidant injection will continue to degrade dissolved phase compounds to non-detectable
concentrations. However, as oxidant is flushed from the treatment zone by groundwater flow and/or
reacts with naturally occurring reductants within the soil matrix, the DNAPL organic concentrations may
increase, but remain at a level that is less than pre-treatment concentrations.
3. PERFORMANCE INDICATORS
Various criteria may be used to assess the performance of in situ remediation technologies such as ISCO.
These performance indicators are described below, particularly as they apply to DNAPL sites.
3.1 Contaminant Mass
The total mass of DNAPL present at a site may be estimated though interpolation and extrapolation of the
spatial distribution of contaminant concentrations in soil; however, this approach is complicated by the
high degree of heterogeneity frequently observed in the distribution of DNAPL in natural geologic
environments. The number of samples required to adequately estimate the DNAPL mass is sufficiently
large that the costs of sample collection and analysis are prohibitive.
3.2 Groundwater Concentration
The most common performance assessment approach is the comparison of pre- and post-treatment
volatile organic compound (VOC) concentrations in a network monitoring wells. In comparison to
DNAPL mass, this approach more closely represents the exposure risks typically associated with
groundwater contamination (i.e., direct ingestion of groundwater containing VOCs). As previously
discussed, VOC concentrations in the monitoring wells measured immediately following the oxidant
injection period are likely to be biased low due to the presence of residual oxidant in the treated zone.
Further, the presence of any amount of DNAPL following ISCO will result in groundwater concentrations
exceeding regulatory criteria since the solubility of these compounds is greater than the criteria by several
orders of magnitude. As a result, monitoring wells located immediately adjacent to the remaining
DNAPL may provide results that are biased high and are not reflective of the overall impact of ISCO
treatment.
A number of potential limitations to this performance assessment approach should be considered during
the design of a post-treatment monitoring program. Since residual oxidant will tend to negatively bias the
post-treatment estimate of the average plume VOC concentrations, monitoring efforts should emphasize
characterizing the long-term, steady-state VOC concentration in the monitoring network. Since the
DNAPL remaining following treatment will result in local zones of high VOC concentrations that may
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
positively bias the average post-treatment plume concentration, the number of sampling points must be
sufficiently large to reflect a representative spatially averaged VOC concentration.
3.3 Groundwater Flux
The ideal performance assessment criterion is the rate of mass removal (expressed as a flux multiplied by
the DNAPL:water interfacial surface area) from the DNAPL source into the groundwater plume. At
steady-state, this rate (termed the plume load with units of M T"1), is equivalent to the rate at which solute
mass in the groundwater plume crosses a spatial plane oriented at a right angle to the direction of
groundwater flow. The plume load is distinguished from plume flux that is the rate of mass flow per unit
area with units of M T"1 L2. In some sense, the collection of a sufficiently large number of samples
randomly located within the groundwater plume will provide an adequate data set for determination of
plume load; however, more cost-effective approaches may be employed to collect plume load data. In the
simplest approach, steady-state VOC concentration data may be collected from an extraction well
pumped at a continuous rate that is sufficient to create a steady-state capture zone that encompasses the
entire groundwater plume. Using the flow rate and average VOC concentration, the plume load may be
directly calculated. While the time required to achieve a steady-state VOC concentration in the extraction
well is a potential constraint, the ease of data collection makes this a potentially attractive approach.
Alternatively, plume load may be determined using an approach made feasible by the advent of
inexpensive multilevel sampling piezometers and drivepoint profiling tools. Using a closely spaced
transect of groundwater samples from a plane intersecting the groundwater plume and oriented at a right
angle to the direction of groundwater flow, the plume load may be calculated using an estimate of the
Darcy velocity and spatial interpolation of the concentration distribution across the sampling transect.
While requiring complex data interpolation and relatively high sample collection and analysis costs, this
approach is rapid in comparison to continuous pumping from an extraction well.
4. FIELD APPLICATIONS
4.1 Features and Performance Observations
Field applications of ISCO are growing rapidly in the U.S. and abroad as highlighted in recent articles and
reports (e.g., Jerome et al. 1997, Schnarr et al. 1998, ESTCP 1999, Lowe et al. 2001, USEPA 1998b,
Siegrist et al. 1999, Yin and Allen 1999, Siegrist et al. 2001). In general, ISCO systems have been shown
to be capable of achieving high treatment efficiencies (e.g., >90 to 99%) for common COCs such as
chlorinated ethenes (e.g., TCE, PCE) and aromatic compounds (e.g., benzene, phenols, naphthalene), with
very fast reaction rates (e.g., >90% destruction in minutes). Field applications have demonstrated that
ISCO can achieve destruction of COCs and achieve clean-up goals at some contaminated sites However,
field-scale applications can also have uncertain or poor in situ treatment performance. Uncertain or poor
performance is often attributed to poor uniformity of oxidant delivery caused by low permeability zones
and site heterogeneity, excessive oxidant consumption by natural subsurface materials, presence of large
DNAPL masses, and incomplete degradation. Assessment of treatment efficiency is commonly based on
sampling and analysis of soil and/or groundwater to enable comparison of post-treatment concentrations
to those present prior to ISCO. These approaches are fraught with problems due to heterogeneities in the
subsurface and the limited number of samples from which inferences are to be made. In addition, simply
characterizing the treated region may not provide the proper information regarding performance as it does
not specifically address changes in contaminant flux that may result from partial cleanup of a source zone
feeding a plume. The following case study illustrates alternative performance assessment approaches as
evaluated during a field trial.
4.2 Case Study Illustrating Performance Assessment Approaches
A pilot demonstration of ISCO using permanganate was conducted in a shallow sandy aquifer (Hood et
al. 2000). The DNAPL source zone consisted of mixture of TCE and PCE as a residual; the dimensions
of the source zone were 1.5 m x 1.0 m x 0.5 m. The groundwater monitoring and oxidant delivery system
consisted of six injection and three extraction wells, along with a fence of multilevel piezometers
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase
containing sample points spaced ~0.5 m horizontally and 0.2 m vertically (Figure 1). The DNAPL source
was flushed with potassium permanganate at a concentration of 8 g/L for 480 days.
The performance assessment approach at the demonstration site utilized a comparison of the three
indicators previously described (DNAPL mass, peak plume concentration, and plume load). DNAPL
mass reduction was based on pre-treatment DNAPL mass estimated using a modeling approach and post-
treatment soil sampling (>300 samples). Peak concentrations in the pre- and post-treatment groundwater
plume were measured as the maximum concentration detected from the multilevel transect. The spatial
distribution of VOC concentrations in the multilevel transect was used to calculate pre- and post-
treatment plume loads. In addition, the steady-state VOC concentrations in the extraction wells were used
as a comparative plume load measurement.
Figure 1: Plan view of test site, including injection wells (IW), multilevel piezometers (ML), and
extraction wells (XW). The shaded box represents the location of the DNAPL source zone.
Injection Emplaced Multilevel!
Wells Source (1 m from source )
.^ *-
/—*
• IW6
• IW5
• IW4
• IW3
• IW2
• IW1
v
o ML1
o ML 2
o ML 3
0 ML 4
o MLS
v*' •*-
o ML 30
i ~4 m
Extraction
Wells
O XW1
• XW2
• XW3
The results of the performance assessment are summarized in Table 1. During post-treatment soil
sampling, DNAPL was not detected in any of the soil samples and only a few detections of sorbed TCE
or PCE were observed, suggesting that the DNAPL was entirely removed. In contrast, the peak plume
concentrations of both TCE and PCE observed in the multilevel transect located immediately down-
gradient of the source zone decreased by factors of only 70 and 2, respectively, relative to pre-treatment
conditions. This relatively minor decrease was consistent with a positive bias in concentration resulting
from the presence of DNAPL, in spite of the detailed soil sampling efforts suggesting the DNAPL was
not present. In contrast to these contradictory results, the observed reductions in the TCE and PCE plume
loads (decreased from the pre-treatment plume loads by approximate factors of 100 and 10, respectively)
measured using both the transect and continuous extraction methods were consistent between
measurement methods.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase
Table 1: Summary of chemical oxidation performance assessment data.
Performance Indicator
DNAPL Mass (kg)
Peak Concentration (ug/L)
Transect Plume Load (mg/day)
Extraction Plume Load (mg/day)
Pre -treatment
(TCE/PCE)
1.6/9.0
142/61
836/854
2,099/2,218
Post-treatment
(TCE/PCE)
ND/ND
2/31
7/98
17/222
ND = non-detectable.
5. SUMMARY
Short-term monitoring programs using a sparse monitoring network to assess the impact of in situ
chemical oxidation on remediation performance can be inadequate and misleading. This is particularly
true for DNAPL sources of groundwater contamination, where such approaches can be subject to either
negative or positive bias. Design of such programs should focus on determining the post-treatment
reduction achieved over a sufficiently long monitoring period so that residual oxidant does not interfere
with the observed COC concentrations. In addition, assessments should rely on steady-state reductions
observed in multiple monitoring wells within the former extent of the groundwater plume rather than
reductions observed in a single monitoring point that could be easily biased. Plume flux is a valuable
performance assessment tool, although its applicability at some industrial sites may be limited by the time
and cost required to complete these measurements using rigorous methodologies.
6. REFERENCES
1. Environmental Security Technology Certification Program (1999). Technology Status Review: In
Situ Oxidation, http://www.estcp.gov.
2. Gates-Anderson, D.D., R.L. Siegrist and S.R. Cline (2001). Comparison of potassium permanganate
and hydrogen peroxide as chemical oxidants for organically contaminated soils. J. Environmental
Eng. 127(4):337-347.
3. Hood, E.D., N.R. Thomson, D. Grossi and G.J. Farquhar (1999). Experimental determination of the
kinetic rate law for oxidation of perchloroethylene by potassium permanganate. Chemosphere,
40(12):1383-1388.
4. Hood, E.D., and N.R. Thomson (2000). Numerical simulation of in situ chemical oxidation.
Proceedings of The Second International Conference on Remediation of Chlorinated and
Recalcitrant Compounds, Monterey, California, May 22-25.
5. Jerome, K.M., B. Riha and B.B. Looney (1997). Demonstration of in situ oxidation of DNAPL using
the Geo-Cleanse technology. WSRC-TR-97-00283. Westinghouse Savannah River Company,
Aiken, SC.
6. Lowe, K.S., F.G. Gardner, and R.L. Siegrist (2001). Field pilot test of in situ chemical oxidation
through recirculation using vertical wells. J. Ground Water Monitoring and Remediation. Winter
issue, pp. 106-115.
7. MacKinnon, L.K., and N.R. Thomson (2002). Laboratory-scale in situ chemical oxidation of a
perchloroethylene pool using permanganate. J. Contam. Hydrol. Accepted and in press.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
8. Schnarr, M.J., C.L. Truax, G.J. Farquhar, E.D. Hood, T. Gonullu, and B. Stickney (1998).
Laboratory and controlled field experiments using potassium permanganate to remediate
trichloroethylene and perchloroethylene DNAPLs in porous media. J. Contam. Hydrol. 29(3):205-
224.
9. Siegrist, R.L., K.S. Lowe, L.C. Murdoch, T.L. Case, and D.A. Pickering (1999). In situ oxidation by
fracture emplaced reactive solids. J. Environmental Engineering. 125(5):429-440.
10. Siegrist, R.L., M.A. Urynowicz, and O.R. West (2000). In situ Chemical oxidation for remediation
of contaminated soil and ground water. Ground Water Currents. Issue No. 37. EPA 542-N-00-006,
September 2000. http://www.epa.gov/tio.
11. Siegrist, R.L., M.A. Urynowicz, O.R. West, M.L. Crimi, and K.S. Lowe (2001). Principles and
Practices of In Situ Chemical Oxidation Using Permanganate. Battelle Press, Columbus, Ohio. July
2001. 336 pages.
12. Struse, A.M., R.L. Siegrist, H.E. Dawson, and M.A. Urynowicz (2002). Diffusive Transport of
Permanganate during In Situ Oxidation. J. Environmental Engineering. Accepted and in press for
April 2002.
13. USEPA (1997). Superfund Annual Report for Fiscal Year 1997. U.S. EPA Office of Solid Waste
and Emergency Response. Washington, B.C.
14. USEPA (1998a). National Water Quality Inventory: 1996 Report to Congress. EPA841-R97-008.
15. USEPA (1998b). In situ remediation technology: in situ chemical oxidation. EPA 542-R-98-008.
16. U.S. EPA Office of Solid Waste and Emergency Response. Washington, B.C.
17. Yin, Y. and H.E. Allen (1999). In situ chemical treatment. Ground Water Remedation Technology
Analysis Center, Technology Evaluation Report, TE-99-01. July, 1999.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
7. PRESENTATION VISUALS ~ presented by Robert L. Siegrist
\VMertoo
V
Site Specific Validation of
In Situ Chemical Oxidation
(ISCO)
Robert L. Sieg rist Eric D. Hood
Professor & Dlreclor
Eiwirnn Sri & Engr.
Colorado School ,' Mr. .
Oi.kk.n. Colorado USA
sl4OTIslgimln4s.edu
Scientist
Grr.Svmrr Consultants
Guelph. OTIMI HJ. Canada
ehood>3tg«osynlec.com
Neil R. Thomson
Professor
CivJl 4 Environ. Engr.
University of Waterloo
Waterloo. Ontario. Canada
nthomsonguwaterioo.ca
NATO/CCMS Country Representatives Hefting
Liege. Belgium
9 - 14 September 2001
In Situ Chemical Oxidation
In situ chemical oxidation (ISCO) involves "delivery
of oxidants into the subsurface to destroy
contaminants and reduce their concentrations and
mass."
During the early 1990's, research confirmed ISCO's
potential viability for in situ remediation:
/ Use of HjO, (Fenton's), O3, KMnO4, NaMnO4
/ For chlorinated solvents and petrochemicals
To date, more than 200 field applications have
occurred with subsurface delivery by:
/ Vertical & horizontal g round water wells
/ Injection probes, fracturing, soil mixing
Fenton's reagentvia
probe Injection at
MGP site in Wisconsin
(Geo-Cleanse)
KMnOj via probe
injection at a TCE
DNAPLsite in
NaMnO4 via 5-spot
vertical wells at a
dissolved phase TCE
Florida (IT Group) site in Ohio (ORNL)
Reactions with Organics
Many organics of concern can be mineralized to CO2,
water, salts and oxides, with possible intermediates
Simplified oxidation stoichiometries for TCE (aqueous):
3H,0, + CjHCL, + Fe , 2CO; + 2H,0 + 3H- + 3Ch*Fe
O, - H,O * C.HCI, > 2CO, • 3H- • 3CI
ZKMnO^ . CjHCIj > 2CO, • ZMnOj * 2K* » H- * SCI
Free-radical (Fenton's, O3) or direct electron transfer
processes (MnCy) are involved
NAPLs can be degraded by oxidation enhanced mass
transfer and oxidative destruction
Reactions with DNAPLs
DNAPL
dissolution
into
groundwater
with no
oxidant
ISCO
enhanced
mass
transfer and
degradation
Distance Vom CNflCl;*ot«i
^^ Reactions with Soil wa^°°
• Natural oxidant
demand (NOD) can be
due to reduced
substances in the c/co
subsurface such as:
,/ Soil organic matter
•/ s-
,r- Fe" and Mn«
r\««n
x
Distance
• NOD can be
significant as it Sample 9/k9 $/m3
affects oxidant
delivery and A '"•'
treatment costs g 126
Subsurface Transport
Advective-dispersive and in some cases diffusive transport
Integration of Processes ™*$°°
Mr,q,
Treatment Zone Pore Volgmes
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
,:"'j* Uiteiioo
^m Site-Specific Validation $
• Validation of ISCO performance goal achievement at
a specific site can include:
~l Soil and/or groundwater sampling to define:
A Concentrations Irt soil andyor groundwater (M L°)
A Contaminant mass before and after ISCO (M)
I Plume mass flux (M T-'L-') or plume load (M T1)
~< Estimates of total mass destruction (%)
~l Toxicity assays (via bioassay methods)
"I Other measures of ISCO function
A Subsurface geophysical mapping
A Soll/groundwater reaction byproducts (Cl )
A SolUgroundwater chemistry (oxidant, pH, Eh, D.O )
,; - i, Waterloo
-m Site-Specific Validation 9
• Validation of ISCO performance goal achievement
at a specific site normally can not include:
~i Measurements of mass recovered as in mass
recovery based methods
"I At present, the use of multicomponent
partitioning tracers is still under study
c^"^ Examples t§.°°
O Field Trial in Canada
Application Description
1 Well-characterized, homogeneous sand
aquifer
/ Residual DNAPL source zone containing TCE
and PCE
t/ Highly instrumented
f ISCO using KMnO4 in a horizontal flushing
mode
HCKXf, 20OQ; HtXri ..rrri T/KMTOKVT, 2001
.y*^^ VV&tertoo
lnj.chon Emptoctd Mwmt«v»li EKIracHoo
W»lls Souic* (1 m horn iouf« J ««•»
/ 0 Mil
1 1 ui 3 ° *WI
• m-
*lw* «M13 * ™2
0 Ml 4 • XW3
• IW2
• IWI o Ml 5
0 Ml M
f^^™ ^^*
Profile View
"KT
V&b VT°°
Operation mode
Pre-oxidation
water flush
(75 days)
Oxidant flush
(484+177 days)
Post-oxidation
water flush
(119 days)
Source co ring
Objectives Monitoring
-characterize flow
-plume load VOCs' Br
-remove DNAPL
-monitor CI-, KMnO4
performance
-residence time
-plume load VOCs' Bf
-mass of DNAPL, VOCs Mn
MnOz
j-'-Jfc Wtiterloo
'^•"iP U
Results
Measure
DNAPL mass
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
© CFB Borden Site in Canada
Application Features
/ Closed system inside sheet pile cell
-' 1.6 kg PCE, -8% residual saturation
•/ Single pass with no oxidant recycling
/ Flush with 10 g/LKMnO,
MacKinnon and Thomson, 2001
c^3
2.5 r I
Profile
View
multileveis
sheet piling
residual
PCE
Monitoring
of reaction
product.
chloride ion,
and PCE in
aqueous
phase and
soil samples
CI-(mg/L)
6000
4000-
2000
1000 2000 3000 4000 5000
TIME (HOURS)
Waterloo
•.' Ch mass balance
accounted for 92% of
initial cr in source
/ No aqueous PCE
•J No DNAPL PCE
0 1000 2000 3000 4000 5000
TIME (hours)
© Field Site in Ohio
Application Features
GWwith TCE at 2,000 ug/L
5 spot pattern at 45 ft. radius
from center injection
GW extraction. 250 mg/L
NaMnOd oxidant reinjection
Sampling & analysis of 1
injection and 4 extraction
wells, and 10 monitoring well
for TCE, reaction products,
biotoxicity
Lowe « *.. 20H, S/sgrisJ « at,, 2001
3 days Injection well 10 days
TCE
(0 - 2300 ug/L)
3 days " Extraction wells 10c,ays
Results
/ 97% overall treatment after
10 days
as measured by a
integrated decrease in
concentrations and an
estimated mass destruction
J No loss in formation Ksat
J No biotoxicity
Closing Remarks
Chemical oxidation is an emerging technology for
in situ remediation and its application is supported
by process principles, R&D, and field experiences
Validation of chemical oxidation at a specific site
can currently utilize a combination of approaches
to measure treatment effects on:
i Contaminant concentrations (soil and groundwater)
~i Plume load (levels at monitoring & recovery wells)
~i Mass destruction (estimated from discrete samples)
~i Toxicity (e.g.. bioassaysf
~i Subsurface geophysics (e.g.. oxidant) and
biogeochemistry (e.g., reaction products)
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF IN SITU PERMIABLE REACTIVE BARRIERS
Volker Birke1
1. THE FUNNEL & GATE SYSTEM AT EDENKOBEN
Setting-up and operating the
full-scale funnel & gate system
at Edenkoben
Dipl.-Geol. M. Rochmes
Dipl.-lng.Th.Woll
Peschla + Rochmes GmbH
Hertelbrunnenring 7
D-67657 Kaiserslautern, GERMANY
tel.+49631-34113-0
fax+49 631/34113-99
E-mail: mrochmes@gpr.de,
TWOLL@GPR.de
URL: www.gpr.de, www.rubin-online.de
Pollutants
Cause of contamination: solvents applied in
production processes (automobile parts)
Av. of single HaloVOCs: 20% TCE, 50%
cisDCE, 30%1,1,1-TCA
At least 3 single plumes, partly overlapping:
- Plume South: TCE, cisDCE, <
8.000 ng/l HaloVOCs
- Plume middle: 1,1,1 -TCA, TCE,
cisDCE, < 20.000jig/l HaloVOCs
- Plume North: PCE, <= 2.000 ng/l
HaloVOCs
Figure 1 - Location of the existing funnel & gate system of
the Edenkoben site
Wall System
Funnel & gate (vertical flow)
Depth of wall: appr. 15 m
Reactive material: Fe° filings
6 gates (each 10 m wide) surrounded by a sheet pile
caisson (open towards the bottom), that covers appr.
8 m below ground level
Continuous sheet pile wall, 400 m long (involves 14 m
of below groundlevel into aquifer base), separating
gates into two chambers (each 1,25 m wide); in the
area of the gate the sheet pile wall was buried down
to 1 m below the anticipated lowest GW level (at 5 m
below ground level) serving as an overflow weir
between the chambers (vertical flow, flow direction
was intentionally lengthened by the reaction zone)
Outside of the gate, the wall in the middle reaches up
to ground level forming the tunnel
Complete connection of the deeper, polluted GW
areas via vertical drainages
r; • • i »>,.•• m M.U-
Figure 2 — Construction of the f & g system
Figure 3 - Right photo: set-up of the vertical drainages
using a large diameter borehole construction method; left
photo: filling the gate with Fe°
Kaiserslautern, Germany, www.gpr.de.www.rubin-online.de.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
2. PRESENTATION VISUALS -presented by Volker Birke
Grouridwater RemscHstfon
using
FUNNEL • and - GATE Technology
PESCHLA -I- ROCHMES GMBh
r
ermeable Reactive Barrier (PRB)
The Solution
Pump and Treat
Permeable Reactive
Barrier
Agenda
Introduction to PRBs
' Project Edenkoben
Pilot Study
Outlook
Type: Permeable Wall
f \l •»
[.,pormeabte wiitl"
Type: Funnel-and-Gate
rr
:i-
PRB Developement
1982 First literature-representations
"permeable treatment beds" (EPA)
1991 Tes, fie|(J jn Borden |Kan j
1994 Commercial ironwall
in Sunnyvale (California)
1996 Workshop in Dresden
1998 First walls in Germany
2001 About 40 full-scale-facilities in
North-America
Metal enhanced dehalogenation
• fniJtiM Kdr**,-*™
• film M*J> i UniilM
3HJO -t 3M-+3OH
-+2» -» H,
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase
Degradation of VOCs
Case Study - Edenkoben
Site: Automotive Industrial Plant
Contaminants: VOCs (PCE, TCE, cDCE,
111TCA)
Constr. Type: Funnel-and-Gate
Funnel: sealed sheet piles
—i^,,,,,. Gates: sheet pile caisson
>•—dtu.,— vertical flowthrough
6"«--—— Reactive Media: Zero-Valent Iron
Edenkoben Site
• hill-!,calc Mill
I.-Unit, length
II (Jcplh
- iitlf i
Gate-Construction
V»^
sh..iKi«c*,**, , .•t«'v» S*^1P11"
-
Gate Hydraulic
Gate -Excavation
Vertical Forced Ftowthrough
Emplacemant of Iron Filings
h.11.1 L, run.
•n*St**Wi*M*t
xibll^l,
Reactor Surface
101
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Gate - Monitoring
Monitoring System
Monitoring Wells
Monitoring Objectives
I. l!,-.....i.m.,,i..: I li<
2. lltilnu-ln Mill-ill l':l|-:iilli-1> I •,
J. Hydraulic Function
4. PrecipitJliun.s
5. Gasprailuctioii
Validation of CHC-Degradation
Conclusions
J The targetted remediation values were
reached and even exceeded
> 98 % effectiveness rate
J No further obstructions on the site
J Low maintenance costs (..passive
system")
U Monitoring - the future activity
Outlook
R&D Project of the
German Federal Ministry for
Education and Research ("BMBF")
"Applying Reactive Barriers and
Treatment Zones in Germany"
Duration: 3 years
Financial scope: Approx 4 Mil Euro
About 10 Projects
6 projects with zero valent iron
-
• PrnHMklE Hncll»
,,l . -:u.|. .1.:, ...ii.
R & D Project
Issues that have to be addressed and
clarified:
Appropriate boundary conditions for
GW- remediation using treatment
walls?
Advantages and limits of this
remediation technology?
102
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
hmrml'NJb
- J-i ..jr« t •!•:•«•+«•
Detailed Objectives
Gaining data from as different cases and
applications as possible for assessing benefits,
drawbacks and applicability of IrEalmBnt walls
Information on design, construction and operating
Impact and benefits regarding the environment
Testing of already Installed trestmeni walls
Reduction of pollutants pertaining to long-term
npecti
Rentabrlity
Developing and establishing quality standards
Contact Information
Theo Woll. project manager
Pei&hla + Rgchmes GmbH
E-mail: lwOll@gpr.de
Phone: +*49 (0)631 34113-50 .. Fax -95
Michael Rochmes. managing director
Peschla * Rochrases GmbH ^ "
E-mail: mroclimes .gS^pr.de
Phone: +*49 (Of S31 341 W-2
•
* i
I
6
PESCHLA + ROCHMES GMBH
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
SITE-SPECIFIC VERIFICATION OF IN SITU REMEDIATION OF DNAPLS
Arun Gavaskar1
Dense nonaqueous-phase liquid (DNAPL) contamination is turning out to be more widespread than first
imagined, especially as site owners and their representatives get better at finding DNAPL source zones.
DNAPL is most commonly encountered at sites contaminated with chlorinated solvents, such as
trichloroethylene (TCE) and perchloroethylene (PCE). These solvents were used in many industrial
activities, such as metal finishing, dry cleaning, and maintenance. Past use and disposal practices have led
to the appearance of these solvents in the subsurface. Because many of these solvents are denser than
water, they often penetrate the water table and continue to migrate downward until they encounter a low-
permeability layer. Depending on the nature of its saturation of the soil pores, DNAPL is considered
either mobile or residual. Mobile DNAPL can be displaced from the pores that it occupies by a strong
hydraulic gradient. Residual DNAPL, on the other hand, cannot be displaced by hydraulic gradient alone,
no matter how strong. Therefore, it cannot be pumped out of extraction wells, as in the case of mobile
DNAPL.
Figure 1: Illustration of a DNAPL Source Zone Forming.
Spill
Source
DNAPL Pool
Many of these solvents are resistant to natural degradation in the solvent phase and are only sparingly
soluble in water. In addition, their mass transfer to the dissolved phase is often further retarded by an
array of factors, such as complex soil pore geometries. Therefore, even a spill or leak of one drum of
solvent can continue to dissolve and contaminate an aquifer for several years or decades. In many
aquifers, the dissolved phase or plume generated encounters little retardation (from factors such as
adsorption or degradation). Therefore, these plumes can often travel long distances and threaten drinking
water sources and other receptors.
1. CHANGES IN DNAPL SITE CHARACTERIZATION
One challenge in finding DNAPL source zones is that their downward migration is governed by geologic
heterogeneities and preferential pathways, rather than the hydraulic gradient. In addition, many sites have
suffered spills and leaks in multiple and often unknown locations. This has led to the presence of multiple
subsurface sources on a single property, resulting in multiple overlapping plumes. At such sites, DNAPL
Battelle. Columbus, Ohio, USA. gavaskar@battelle.org
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sometimes may occur in counterintuitive locations. At many sites, even those with an apparent plethora of
monitoring wells, the monitoring well density may not be enough to distinguish between multiple plumes,
let alone multiple sources. For example, at one of the most challenging sites, Operable Unit 5 in Hill Air
Force Base, Utah, fairly extensive initial monitoring led to the discovery of what was thought to be only
one plume (see Figure 2). Subsequently, additional monitoring led to the identification of three plumes.
An expert panel that recently reviewed the abundant monitoring data could not be sure whether the three
plumes originated from a single source or multiple sources. Multiple wells and soil borings over
approximately one square mile of suspected source area have failed to reveal any definite sources.
Whether or not a source, if it is narrowly defined as DNAPL or solvent phase, still exists at this site is not
yet clear. If such a source exists, the DNAPL mass is probably relatively small, but diffuse.
Figure 2: TCE Plumes at Operable Unit 5, Hill Air Force Base, Utah (Source: Montgomery Watson,
2001).
Hill Air Force Base
Property Boundary
2. CHALLENGES IN DNAPL SITE REMEDIATION
There are two schools of thought on how to deal with DNAPL sites; both schools represent thoughtful
and valid arguments, indicating that the learning process still continues.
One school of thought argues that most DNAPL source zones are recalcitrant to characterization and
treatment. In this school, success is ultimately measured by an improvement in downgradient
groundwater quality (reduction in dissolved contaminant concentrations to target cleanup levels at a
downgradient compliance boundary, which is often the property boundary). Proponents of this school use
three arguments:
(a) The practical difficulties encountered in finding and delineating DNAPL sources
(b) The technical and economic limitations in removing 100% of the DNAPL mass at a site
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(c) Modeling simulations, which show that DNAPL mass removal would have to be nearly 100%, before
any significant improvement in groundwater quality is encountered at the compliance boundary
(Freeze and McWhorter, 1997; Cherry et al, 1996).
The first school argues that at many sites, because of the complex nature of the DNAPL distribution, even
the best characterization efforts may fail to completely delineate the source and some parts of the DNAPL
source could fall outside the zone targeted for remediation. Therefore, not only is DNAPL remediation
limited by the technical and economic limitations posed by the asymptotic nature of DNAPL mass
recovery encountered during most remediation applications, but that the intrinsic complexity of the
DNAPL distribution at most sites assures an outcome that is less than 100% successful in removing the
source. This would lead to the continued presence of a dissolved contaminant plume that the site owner
would have to address. A better approach at many sites would be to leave the source alone and focus the
remedy on containing the plume.
The second school of thought primarily argues that any DNAPL mass removal is welcome. Success need
not be defined so absolutely. Site owners are getting better at characterization and at finding and
delineating DNAPL source zones. As long as DNAPL source zones are reasonably well defined and
remediation technologies are able to remove a reasonable amount (say, 60 to 90%) of DNAPL mass from
the affected aquifer, there is a good chance that the resulting plume is weakened to the point where
natural attenuation may be sufficient to achieve target cleanup levels at a downgradient compliance
boundary. Even if an active remedy, such as a pump-and-treat system, is required to contain a post-source
remediation plume, the life of the plume would probably have been greatly reduced by the weakening of
the source that feeds it. In addition, this school argues that models showing persisting downgradient
plume concentrations, following substantial DNAPL mass removal, are based on homogeneous aquifers.
In most aquifers, which are heterogeneous to varying degrees, removal of some DNAPL mass (probably
from the more permeable regions of the aquifer, where most remediation technologies are particularly
effective) would cause the bulk of the groundwater flow to encounter less DNAPL. Most of the remaining
DNAPL would be trapped in pores that are inaccessible to the bulk flow. Therefore, in most cases,
downgradient contaminant concentrations should be lower, following substantial DNAPL mass removal.
3. IMPLICATIONS FOR SITE OWNERS
Because both schools of thought present valid arguments backed by theoretical simulations and practical
experience, it appears that DNAPL sites will have to be approached on a case-by-case basis. The first
school's argument is strengthened by the fact that at many sites, such as former NAS Moffett Field and
Dover AFB, passive plume containment remedies, such as natural attenuation or permeable barrier have
been found to be effective and economical (Gavaskar et al., 2000; Gavaskar et al., 1998). Even an active
remedy, such as a pump-and-treat system, is not as uneconomical as it used to be. With the development
of concepts, such as slow pump and treat (Cherry et al., 1996), in which pumping is conducted at the
lowest rate necessary to contain a plume, at many sites, it may be possible to contain fairly large plumes
with relatively small pump-and-treat operations (1 to 5 gal/min). Previously, more aggressive pump-and-
treat operations aimed at treating and removing the plume were much more costly. In addition, at some
sites, pump-and-treat systems are already installed as an interim remedy and could be optimized for more
effective containment and favorable economics. The development of high capacity and more compact
"low-profile" or tray-type air strippers has also contributed to reducing the space and cost requirements of
pump-and-treat systems (Battelle and Duke Engineering & Services, 2001). In addition, as seen at
Operable Unit 5, Hill Air Force Base, the probability of even finding the DNAPL source may be minimal.
However, there are also sites where the technical feasibility and economics may favor source delineation
and remediation. For example, at some sites, such as Naval Air Station Pensacola, Florida, the source
zone has been more broadly defined as the area inside the isopleth with the highest concentration of the
contaminant (see illustration of this type of site in Figure 3). Because this high-dissolved phase
concentration area identified was relatively small, source remediation efforts were focused in this
suspected source area without additional effort to find actual DNAPL phase. Therefore, DNAPL site
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characterization and remediation is as much an art as a science; much is left to the collective judgment of
site owners and their representatives (scientific consultants and attorneys), regulators, and other
stakeholders.
Figure 3: Suspected Source Area Ringed by Highest Identified Groundwater Concentration.
mg/L TCE isopleth 1 mg/|_ TCE
Suspected
DNAPL
Source
Groundwater
Flow Direction
10 mg/L TCE
At Launch Complex 34, Cape Canaveral Air Station, Florida, for example, TCE has entered the
subsurface in such large quantities that a moderate characterization effort (relative to the size of the site)
was able to find and adequately delineate the source. In addition, the large mass of DNAPL, perched on a
relatively thin clay aquitard underlying the surficial aquifer, was threatening the confined aquifer below.
Although there are signs that over the last 30 to 40 years, some DNAPL has progressed to the confined
aquifer in areas where the aquitard is particularly thin, removal of DNAPL mass from the surficial aquifer
has greatly reduced the risk to the confined aquifer. Significant contamination of confined aquifers due to
DNAPL present in surficial aquifers is a risk that potentially threatens drinking water supplies and
increases the potential costs of any future remediation or plume containment efforts.
The first school would argue that remediation of the source zone increases the risk of DNAPL migration -
downwards or to the sides; this may increase the contamination in the aquitard or the cleaner confined
aquifer below or it may lead to a widening of the source, and hence, the plume in the surficial aquifer.
Therefore, remediation of the DNAPL in the surficial aquifer would have to be done in a way that
minimizes the potential for further downward migration of DNAPL due to the remediation technology
application itself. This would seem to favor technologies that promote destruction of the DNAPL in the
subsurface, rather than those that promote mobilization and extraction of the DNAPL to the surface for
aboveground treatment. Much better hydraulic control would be required for DNAPL mobilization
technologies, although engineering controls are necessary for any source remediation effort.
4. CHALLENGES IN DEFINING AND VALIDATING THE SUCCESS OF DNAPL
SITE REMEDIATION
DNAPL is a relatively new problem. The widespread nature of this problem was first recognized in the
1990s. Remediation and monitoring approaches for this problem are still evolving. One shortcoming in
several DNAPL remediation technology demonstrations has been inadequate monitoring and/or the
limitations of the monitoring instruments themselves. Two demonstrations in the U.S. that have attempted
more comprehensive monitoring of DNAPL source zones and the effects of the remediation efforts are
the Interagency DNAPL Consortium's (IDC) demonstration of three remediation technologies—chemical
oxidation, resistive heating, and steam injection - at Cape Canaveral Air Station (Battelle, 2001 a and b)
and the Environmental Security Technologies Certification Program's (ESTCP) demonstration of
surfactant flushing at Marine Corps Base at Camp Lejeune, North Carolina (Duke Engineering &
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Services, 2000). Although different monitoring tools were used in the two demonstrations, considerable
effort was made in both demonstrations to track, not just the reduction in groundwater concentrations and
any aboveground DNAPL recovery (as is typical in previous remediation efforts), but also the initial mass
and fate of the DNAPL in the aquifer.
Figure 4: DNAPL Source Zone (300 mg/kg and higher contours) at Cape Canaveral Air Station
Identified through Extensive Soil Sampling.
LOWER SAND UNIT
The apparent success or failure of DNAPL treatment can sometimes be a matter of data collection and
interpretation. As an example, Table 1 presents a restricted data set from the resistive heating
demonstration at Cape Canaveral Air Station representative of the level of monitoring and data collection
conducted at many remediation sites. All the data in Table 1 indicate success at removing DNAPL mass
(1,947 kg of TCE recovered aboveground) and improving groundwater quality (as much as 99% decline
in groundwater TCE concentrations). Much of the remaining TCE appears to have been degraded by the
treatment, as evidenced by the increase in chloride.
On the other hand, Table 2 shows the results of more comprehensive monitoring conducted at the Cape
Canaveral site, through characterization and estimation of the pretreatment DNAPL mass, installation and
monitoring of depth-discrete perimeter wells, and analysis of the pre- and post-treatment groundwater
geochemistry. Extensive soil sampling and kriging (statistical analysis) were used to obtain a range of
estimates for the pre-treatment and post-treatment TCE mass, at the 80% confidence level. Spatial
coverage of the heterogeneous DNAPL distribution was improved by collecting nearly 300 soil samples
during each event from the 75 ft long x 50 ft wide x 45 ft deep test plot in the DNAPL source zone.
Methanol extraction procedures for the soil samples were modified to allow extraction of larger aliquots
of soil, thus allowing the entire subsurface soil column to be extracted and analyzed at each of 12
locations in the test plot. The main advantage of depth-discrete groundwater and soil sampling over some
other tools is that spatial coverage is not dependent on geologic heterogeneities in the aquifer or on
specific DNAPL properties. Collecting a sufficiently high number of soil samples, with the number being
determined by the expected variability of the TCE distribution and the desired level of statistical
confidence, gave the site owner reasonably good estimates of the pre- and post-demonstration TCE
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masses. Of course, this degree of characterization and monitoring is not likely to be economically feasible
for most full-scale remediation sites. However, in the early stages of development of DNAPL source
remediation options, comprehensive monitoring is necessary to identify potential shortcomings of the
remediation approach and design improved applications at future sites.
Table 1: Interpretation of DNAPL Remediation by Resistive Heating at Cape Canaveral Air Station with
a Basic Monitoring Scheme Typical of Many Remediation Projects.
Monitoring Parameter
TCE in Source Zone Well PA-13I
TCE in Source Zone Well PA- 141
TCE in Source Zone Well PA-14D
TCE Mass Recovered Aboveground in
Extracted Vapor
Chloride in source zone well PA-13D
Chloride in source zone well PA-14D
Pre-Treatment
Level
1,070,000 u.g/L
960,000 u.g/L
868,000 u.g/L
~
774 mg/L
774 mg/L
Post-Treatment
Level
60,200 u.g/L
174,000 u.g/L
2,730 |ag/L
1,947 kg
3,610 mg/L
4,790 mg/L
Change
- 94 %
- 82%
- 99%
~
+ 366%
+ 519%
The more comprehensive data in Table 2 now indicate a strong probability that the DNAPL mass
recovered aboveground is a fraction of the DNAPL mass that was initially in the subsurface. Because the
TCE mass recovered aboveground does not account for the entire difference between the pre- and post-
demonstration TCE masses, it is probable that substantial amounts of TCE either degraded or migrated
from the treatment plot. Possible pathways for TCE degradation include enhanced biodegradation (due to
the enhanced action of microbes at elevated temperatures) and/or abiotic reduction (due to reaction with
cast iron shot used in the heating electrodes). However, chloride, which could have been a key indicator
of the degradation pathway, loses some significance due to the fact that the substantial increase in
groundwater chloride was accompanied by a similar increase in other dissolved ions, namely, sodium,
potassium, calcium, and carbonate (alkalinity), which are all seawater constituents.
Given the closeness of this site to the ocean and the presence of relatively high salinity in the pre-
treatment groundwater at the base of the surficial aquifer, the possibility that the treatment somehow
enhanced saltwater intrusion into the test plot cannot be ruled out. This leads to the possibility that some
DNAPL migrated out of the test plot during the treatment. Possible pathways for migration include heat-
induced volatilization to the vadose zone and atmosphere and the sideways spread of the deeper TCE
caused by an intermediate silt layer in the otherwise sandy aquifer. Although the resistive heating
technology successfully heated even the more difficult parts of the target aquifer, such as the soil
immediately above the clay aquitard at 45 ft below ground surface and the portion of the aquifer under a
building, more engineering controls will be required at future site to manage the collection of mobilized
TCE, especially in difficult geologic settings.
At Cape Canaveral Air Station, the demonstration of chemical (permanganate) oxidation treatment of the
DNAPL in a separate test plot was more conclusive. As seen in Table 3, the disappearance of TCE mass
from aquifer in the test plot (treated portion of the DNAPL source zone) and the monitored changes in
groundwater present a more integrated picture of TCE oxidation as the major pathway of DNAPL mass
removal. The significant increase in chloride in the treated aquifer was not accompanied by a consistent
increase in sodium, another major seawater constituent. At the same time, alkalinity (carbonate) levels in
the groundwater increased, as would be expected when carbon dioxide generation (oxidation of organic
species) occurs in the surficial aquifer. Visual evidence of purple discoloration of soil and groundwater in
the treatment zone indicated good distribution of the potassium permanganate oxidant. Pre- and post-
treatment slug tests did not indicate any changes in hydraulic conductivity of the aquifer following
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treatment. Monitoring of deeper wells and soil cores showed no evidence of DNAPL in the confined
aquifer below. Levels of some trace metals (chromium, nickel, and thallium) that were present in the
industrial grade potassium permanganate injected in the aquifer rose temporarily, but are expected to
subside, once the treatment zone re-equilibrates with the groundwater flow.
Table 2: Interpretation of DNAPL Remediation by Resistive Heating at Cape Canaveral Air Station with
a More Comprehensive Monitoring Scheme.
Monitoring Parameter
TCE in Source Zone Well PA-13I
TCE in Source Zone Well PA-14I
TCE in Source Zone Well PA-14D
TCE Mass in Aquifer
(80% confidence interval)
TCE Mass Removed from Aquifer
(80% confidence interval)
TCE Mass Recovered Aboveground in
Extracted Vapor
Chloride in source zone well PA-13D
Chloride in source zone well PA-14D
Sodium in Source Zone Well PA-13D
Sodium in Source Zone Well PA-14D
Pre-Treatment
Level
1,070,000 u.g/L
960,000 u.g/L
868,000 u.g/L
7,498 to 15,677 kg
~
~
774 mg/L
774 mg/L
369 mg/L
325 mg/L
Post-Treatment
Level
60,200 u.g/L
174,000 u.g/L
2,730 |ag/L
1,031 to 1,535 kg
5,963 to 14,646 kg *
1,947 kg
3,610 mg/L
4,790 mg/L
2,070 mg/L
3, 130 mg/L
Change
- 94 %
- 82%
- 99%
- 80 to 93%
~
~
+ 366%
+ 519%
+ 461%
+ 863%
* Estimated as the difference between the pre-treatment and post-treatment TCE mass estimates in the aquifer. This
TCE mass removed estimate is significantly higher than the TCE mass of 1,947 kg recovered aboveground
Therefore, at least during the continuing developmental phase of in-situ DNAPL remediation
technologies, a comprehensive characterization of pre-treatment and post-treatment contaminant mass,
aquifer geochemistry and hydrology, and the regions surrounding the treated source zone is desirable to
understand the true effectiveness of the treatment. Once these remediation technologies are proven and
the level of engineering controls appropriate for each class of technology has been identified, it is
anticipated that characterization and monitoring requirements will gradually recede. For a well-
engineered treatment system, the primary pre-treatment characterization objective would be identification
of the boundaries of the DNAPL source zone and distribution of the hot spots in the zone, not the exact
DNAPL mass. This would ensure that the treatment is targeted where it is most needed, and minimize
(but not fully eliminate) the potential for unidentified pockets of DNAPL pockets outside the treatment
zone. The primary post-treatment monitoring objective would be a reduction in groundwater
concentrations of the contaminants to target cleanup levels at the compliance boundary. Long-term
monitoring would be required to ascertain that the cleanup levels are sustainable and are not subject to a
rebound in groundwater contaminant concentrations, once a new post-treatment equilibrium is established
in the aquifer.
If the target (regulation-mandated or risk-based) cleanup level is not achieved or achievable in the long
term at the compliance boundary, a secondary treatment would be required. The secondary treatment
could take any one of several forms - natural attenuation, pump-and-treat system (albeit for a shorter
future period and for a weaker plume), or secondary source treatment (probably, some form of enhanced
bioremediation). In this sense, three time-based goals are envisioned for remediation of a DNAPL source
zone:
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Table 3: Interpretation of DNAPL Remediation by Chemical Oxidation at Cape Canaveral Air Station
with a More Comprehensive Monitoring Scheme.
Monitoring Parameter
TCE in Source Zone Well BAT-2S
TCE in Source Zone Well BAT-2D
TCE Mass in Test Plot Aquifer
(80% confidence interval)
Chloride in source zone well BAT-2S
Chloride in source zone well BAT-2D
Sodium in Source Zone Well BAT-2S
Sodium in Source Zone Well BAT-2D
Alkalinity (carbonate0) in Source Zone Well
BAT-2S
Alkalinity (carbonate0) in Source Zone Well
BAT-2D
Pre-Treatment
Level
1,1 10,000 (o,g/L
1, 160,000 |ag/L
6,217 to 9,182 kg
Same as above
53mg/L
722 mg/L
28mg/L
305 mg/L
316
208
Post-Treatment
Level
<5^g/L
220,000 |ag/L
1,5 11 to 2,345 kg a
2,980 to 3, 182 kg b
126 mg/L
5,070 mg/L
68 mg/L
91 mg/L
1,500 mg/L
1,300 mg/L
Change
- 99 %
- 81%
- 62 to - 84%
- 49 to - 68%
+ 138%
+ 602%
+ 143%
- 70%
+ 375%
+ 525%
a TCE mass based on soil sampling conducted immediately following end of oxidant injection treatment.
b TCE mass based on soil sampling conducted nine months after the end of oxidant injection treatment. The
differences between the TCE mass change estimated at the two time points are indicative of sampling variability.
0 Carbonate buildup is indicative of carbon dioxide production through oxidation of organic species.
• A short-term goal, which targets maximum achievable DNAPL mass removal. This goal is generally
determined by economic considerations and represents an end point for the primary treatment when
the short-term cost of achieving incremental DNAPL mass removal becomes excessive. Achievement
of this goal can be verified through the use of groundwater and soil sampling or other tools, as well as
analysis of any side-streams recovered aboveground.
• An intermediate-term goal, which targets achievement of desired cleanup levels at the compliance
boundary. It may take a year or several years for flow to re-equilibrate and for extraneous factors
(such as diffusion of sequestered contaminants from downgradient fine-grained aquifer media) to
subside, before the site owner can even make a determination that the target cleanup level has been
achieved at the compliance boundary. It should be noted that the same is the case when source or
plume containment, rather than source remediation, is the selected option at a site. For example, in
Figure 2, an aeration trench has been implemented near the property boundary as a permeable barrier
inside the TARS plume, for the last two years. Although this treatment is effective in terms of the
quality of the treated water emerging from the interceptor trench, the downgradient portion of the
TARS plume in Figure 2 shows no sign of receding or detaching from the upgradient plume or
source. This persistence of downgradient contamination is probably because of the abundance of silty
clay lenses, from which contaminants continue to diffuse slowly over time, thus re-contaminating the
treated water. Similar persistence of downgradient contamination for several years following effective
containment of the plume at the treatment point has been noted at former NAS Moffett Field
(Gavaskar, et al. 1998), a site which has a somewhat similar composition of sand channels and clay
deposits. Therefore, irrespective of the approach, be it source remediation or plume containment, at
many sites, achievement (or non-achievement) of the intermediate goal, which is generally the most
important goal that site owners and regulators are interested in, may not be apparent for a year or
several years after implementation of the selected remedy.
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• The long-term goal of any remediation ultimately would be achievement of regulatory cleanup levels
or maximum contaminant levels (MCLs) in the source zone and plume, which would indicate that
long-term monitoring and/or plume control measures can be dismantled.
The process seems formidable, but as each goal is reached, the costs of managing a site probably decline.
The decision making process involved in selecting the appropriate remedy or chain of remedies and for
selecting the tools for characterization and monitoring is driven by a mix of technical, regulatory, and
economic factors that is determined on a site-specific basis.
5. REFERENCES
1. Battelle, 2001 a. Chemical Oxidation of a DNAPL Source Zone at Launch Complex 34 in Cape
Canaveral Air Station. Draft-Final Report prepared for the Interagency DNAPL Consortium by
Battelle, Columbus, Ohio. June 6.
2. Battelle, 2001 b. Six-Phase Heating ™ (SPU™) Treatment of a DNAPL Source Zone at Launch
Complex 34 in Cape Canaveral Air Station. Draft-Final Report prepared for the Interagency DNAPL
Consortium by Battelle, Columbus, Ohio. September 28.
3. Battelle and Duke Engineering & Services, 2001. Cost and Performance Report for Surfactant-
Enhanced DNAPL Removal at Site 88, Marine Corps Base CampLejeune, North Carolina. Prepared
for Naval Facilities Engineering Service Center, Port Hueneme, California by Battelle, Columbus,
Ohio and Duke Engineering & Services, Austin, Texas. October 9.
4. Cherry, J., S. Feenstra, and D. Mackay. 1996. Concepts for the Remediation of Sites Contaminated
with Dense Non-Aqueous Phase Liquids (DNAPLs). In Dense Chlorinated Solvents and Other
DNAPLs in Groundwater. Edited by J. Pankow and J. Cherry, Waterloo Press, Portland, Oregon.
5. Duke Engineering & Services, 2000. Surfactant-Enhanced Aquifer Remediation at Site 88, MCB
Camp Lejeune, North Carolina. Final. Prepared for Naval Facilities Engineering Service Center, Port
Hueneme, California by Duke Engineering & Services, Austin, Texas.
6. Freeze, R., and D. McWhorter, 1997. A framework for assessing risk reduction due to DNAPL mass
removal from low-permeability soils. Groundwater. Volume 35, Number 1: pgs 111-123.
7. Gavaskar, A., B. Sass, N. Gupta, J. Hicks, S. Yoon, T. Fox, and J. Sminchak, 1998. Performance
Evaluation of a Pilot-Scale Permeable Reactive Barrier at Former Naval Air Station Moffett Field,
Mountain View, California. Final Report prepared for Naval Facilities Engineering Service Center,
Port Hueneme, California by Battelle, Columbus, Ohio. November 20.
8. Gavaskar, A., N. Gupta, B. Sass, W. Yoon, R. Janosy, E. Drescher, and J. Hicks, 2000. Design,
Construction, and Monitoring of a Permeable Barrier in Area 5 at Dover AFB. Final Report prepared
for the Air Force Research Laboratory, Tyndall AFB, Florida by Battelle, Columbus, Ohio. March 31.
9. Montgomery Watson, 2001. Draft Conceptual Model Report for Operable Unit 5. Prepared for Hill
Air Force Base, Utah by Montgomery Watson, Salt Lake City, Utah. May.
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6. ACKNOWLEDGEMENTS
The DNAPL remediation demonstration at Cape Canaveral Air Station was funded by the Interagency
DNAPL Consortium (IDC) led by the U.S. Department of Energy, Environmental Protection Agency's
Superfund Innovative Technology Evaluation (SITE) Program, Naval Facilities Engineering Service
Center (NFESC), and National Aeronautic and Space Administration (NASA). The permeable barrier
projects, at former NAS Moffett Field and Dover Air Force Base, were funded by the Environmental
Security Technologies Certification Program (ESTCP) through NFESC. The Hill Air Force Base
information was provided by the U.S. Air Force and Montgomery Watson to the author as part of an
expert panel review and advisory process to identify characterization and remediation strategies for
Operable Unit 5.
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7. PRESENTATION VISUALS ~ presented by Arun Gavaskar
Site-Specific Validation of
In-Situ Remediation ofDNAPL
Presented at NATO Special Session
September 11.2001
By
Arun R. Gavaskar
Battelle
505 King Avenue, Columbus, Ohio 43201
USA
gavaskar@battelle.org
Site Categories with Significant DNAPL
_ Chlorinated solvent sites (e.g. perchloroethylene [PCE],
trichloroethylene [TCE])
• Drycleaners
' Maintenance (Aircraft, ships, automotive)
' Metal finishing (vapor degreasing)
' Electronics manufacturing
' Fire training areas
Wood treaters (polycyclic aromatic hydrocarbons [PAHs])
Manufactured Gas Plant (MGP) sites
DNAPL Site Strategies
- What are the Remediation Options Available?
m Source Identification and Remediation (growing interest)
• Excaralionl Soil Vapor Extracllon
• Healing (Resistive or Steam)
* Chemical Oxidation (Permanganate or Fenton's reagent)
• Surfactanl flushing
• SourcelPlume Containment (most commonly done)
• Natural atlenualion
* Pump and treat (slow)
• Permeable barriers (e.g., zerovalent iron, air sparging, biological)
• Plume Treatment (becoming rare)
• Pump and treat (aggressive]
1 Enhanced bioremedlation or bioaugmentation
• Secondary Treatment or DNAPL (becoming an issue)
• Treating the residuals left behind by primary treatment
Batteite
DNAPL Remediation at Cape Canaveral Air Station
- /nteragency DNAPL Consortium
Finding and Characterizing ONAPL Source at Cape Canaveral
- Site Characteriiation/ Performance Assessment Tools
"-1 _*5T<
DNAPL source characterization and in-eitu treatment (75 ft x 50 ft
test plots)
• Six-Phase Heating
' Chemical Oxidation
' Steam Injection
Outdoor and indoor characterization may be required
• RN«PL Is o(!en under buiIding5
Continuous soil cores from ground surface to aqultard (45
ft bgs) collected and extracted in the field
12 soil coring locations x 23 two-foot samples per location
in each test plot [entire two-foot length of each sample was
extracted)
Performance Strategy and Goals
• Cape Canaveral Air Station
Overall goal - Meet Florida State-mandated maximum contaminant
level (MCL) targets in DNAPL Source Area: 3 uglL TCE, 70 uglL
DCE. and 1 uglL vinyl chloride
_ Goal for Remediation Vendors - Remove 90% of initial DNAPL
mass
Performance Assessment Methodology
• Primarily, detailed soil sampling
' Secondarily, detailed groundwater and air emissions sampling
to verify fate of chlorinated volatile organic compounds
(CVOCa|
- Are CI/OCs being destroyed?
- Is DNAPL migrating to surrounding regions?
- Are ail the CI/OCs removed from the test plot being captured
abavsgtannd?
Performance Strategy and Goals
- Technical tapracticaMlrty Waiver Guidance
j "...Sources should be located and treated or removed
where feasible and where significant risk reduction will
result, regardless of whether EPA has determined that
groundwater restoration is technically impracticable..."
[in other words, a DNAPL source should be located
and treated as efficiently as possible, even though
any remaining DNAPL may prevent the remediation
from achieving MCLs (e.g., 5 ua/L of TCE).
Inability to remove 10ff% of the source should not
stop sites from attempting DNAPL source treatment]
Directive 9234.2-25
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NATO/CCMS Pilot Project Phase III
Monitored Natural Attenuation Policy
• ",,. EPA expects that MNA will be most appropriate
when used in conjunction with other remediation
measures (e.g., source control, groundwater
extraction), or as a follow up to active remediation
measures that have already been implemented..."
Directive 9200.4-17P
Del Amo Record of Decision (ROD) Excerpt
- Benefits ofDNAPL Source Treatment
- "...When NAPL is recovered from the ground, its mass
and saturation are reduced. In principle, this can (1)
reduce the amount of time that the containment zone
must be maintained, (2) reduce the potential for NAPL to
move naturally either vertically or laterally, and (3)
increase the long-term certainty that the remedial action
will be protective of human health and remain effective..."
Cape Canaveral Remediation - Validation of Performance
- Contouring (Linear Interpolation) and Kriging Mass Estimates in
Chemical Oxidation Plot
Prettsatment Mass Post-treatment Mass
M M
Method
Contouring
•TotilTCE
Contouring
•WMPL
Kngmg
. Totil TCE
A>g.
6,122
5,039
7,699
80«
Confidence
Interval
6,217 -
9.1B2
A*.
1.100
110
1.9Z8
80*4
Interval
1.511-2.H5
Removal
A*
82 S
84%
7S-,
MM
Confidence
Intern!
62-84%
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Cape Canaveral Remediation - Validation of Performance
• Using Perimeter Monitoring Wills.Surface Emission Tests, and Hydraulic
JWsjsuremente to Evaluate Potential lor TC& DNAPL tJKgration
Monitonng wells on perimeter of
treatment are? used to monitor for
sharp increases in CVOCs that would
As cocifinng fayef IS relatively thin.
monitoring »ells were required in the
confined aqurfer below
Surface emission testing is desirable.
especially for thermal (e g , steam
injection) or exothermic technologies
(eg Fenton'sreagent)
Water level measurements and slug
tests used to determine unusual
changes in hydraulic behavior of the
aquifer before, during, and after the
remediation
DNAPL Source Treatment - Economics
- Present Value (PV) Analysis of Cnemrca* Condition versus Pump-iml-TrfatitCipi
Canaveral
Total cost of chemical oxidation (three injection events) in 75 ft x
50 ft x 40 ft test plot - $850,000
• Assumed that natural attenuation is sufficient to control a weakened plume
• If further source control or plume control is required, total cost will be higher
Present value of equivalent pump-and-treat system (2 gpm) for
containment of ONAPL source for the next 30 years = $1.032,000
• Include! capital investment of $102,000
• Include* routine annual O&M cost of $44.000 (2.9% discount rate)
* Periodic equipment replacement costs
Monetary advantage of source treatment is not immediately
obvious from PV analysis
• Risk reduction and earlier (long-term) dismantling of plume control measures
are trie main benefits
What if we cannot find the source, or the source is likely to be
relatively small or weak?
- Treatment of hot spots or plume control may be better remedy
Strong DNAPL Source
Weak or Dispersed DNAPL Source
Private Manufacturing Site Strategy
_ Selectively characterize hot spots and uncharacterized
areas under the buildings
Determine why TCE is biodegrading to DCE and VC, but
DCE and VC continue to persist
Make a judgment on whether it would be more
economical to treat (biologically or otherwise) TCE hot
soots or contain/ treat DCE plume
• Get agreement from EPA on suitable end point/ closure
strategy
• Apply the selected remedy
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NATO/CCMS Pilot Project Phase III
What if DNAPL Source Remediation Removes only a Part of the Source?
- The need for secondary treatment of DNAPL source
Naval Air Station Pensacola.
Florida: 30 ft x 80 ft source
Confining clay layer 40 ft bgs
Initial TCE = 3,000 ppb in
source area
• Primary treatment: Fenton's
Reagent Oxidation
Post-Fenton's Treatment
TCE level = nondetect
Rebound: Six months after
MMtpif,»iriw» treatment, TCE = 100 ppb
Rebound: One year after
treatment = 500 ppb
to KK of imSii DNAPL source noss m Rebound: 1.5 years after
treatment - 500 ppb
Viability of Secondary (Long-Term) Treatment of DNAPL
Source
Soil from Low-Dose Region
Soil from High-Dose Region
Primary remediation is
never uniform - some
regions receive higher
dose of treatment agent
(e.g., permanganate or
heat) than other regions
Can microbial
populations survive in
the low-dose and/or high-
dose regions?
Can these surviving
populations be
stimulated to enhance
degradation of
contaminants?
Heterotrophic Counts (CFU/mL)'"
Region Aerobic Anaerobic
Secondary Treatment of DNAPL Source
- Approximate Cost of Carbon Sources
ftK&teitant Cdrrpoumfc, Etatttll* Prm, 2000,
Carbon Source
Lactote
Ethanol
Vegetable Oil
HRC™ (poly-acetate)
Methanol
Cost (t/lb o1carbon)
1.0 to 2.2
0.20 to 0.25
0.20 to 0.50
12.00
0.04 to 0.05
Strategy for Chlorinated Solvent Sites, Part 1
- For Long-Term Economical Remediation
_ Conduct select ve additional site characterization to determine if
an active source or DNAPL can be identified
• Soil gas survey
• Depth-discrete monitoring points or wells
If source can be identified and can be economically treated, focus
on source treatment (e.g., oxidant injection)
• Short-Term Goal Remove as much DNAPL as economical
• Intermediate Term Goal: Secondary treatment (eg.carbon source or
some plume control (e.g., natural attenuation or pump-and-treat)
• Long-Term Goal: Earliest possible dismantling of plume control
system possible
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NATO/CCMS Pilot Project Phase III
Strategy for Chlorinated Solvent Sites. Part 2
• For Long-Term Economical Remediation
_ If source cannot be identified or is too disperse or is too
uneconomical to treat, then focus on plume control
• Try and obtain a Tl waiver for on-property contamination
• Evaluate aquifer characteristics for risk assessment and
determine the feasibility of natural attenuation
' Determine if hots pots can be treated with enhanced
bioremediation (addition of carbon source) or by
bioaugmentatian (introducing suitable microbes)
• If plume is a threat to potential receptors, treat plume at
property boundary
- Evaluate permeable barriers or pump 4 treat systems or other
active remedy
Site-Specific Validation of
In-Situ Remediation ofDNAPL
m Arun R. Qavaskar
• Battelle, 505 King
Avenue, Columbus, Ohio
43201, USA
- gavaskar@battelle.org
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
FURURE DEVELOPMENTS IN VERIFICATION OF IN SITU PERFORMANCE:
EXPECTATIONS, INSTRUMENTS, AND GOALS
Bert Satijn1
1. KEY ISSUES OF TECHNICAL PRESENTATIONS
The second day of the NATO/CCMS special session is dedicated to the technical issues of in situ
technologies and validation aspects. This last presentation reviews technical contributions and picking up
the key issues. These will be used as a base for a presentation of future developments in the field of
performance testing and validation processes.
1.1 Soil Vapor Extraction- Michael Altenbockum
In Germany a large-scale review of executed soil vapor extraction projects has been executed. It became
clear that in many cases the project team was not very well aware of the processes in subsoil. The overall
conclusion of the reviewer was "They don't know what they are doing". Performance testing and
validation was not done properly due to lack of experience and knowledge of the actual geochemical
phenomena in the soil.
Energy consumption seemed to be a good parameter for cost efficiency. Energy is not only the important
factor for the costs, but in relation with the total quantity of removed contaminants, it provides a good
indication for the removal efficiency and environmental efficiency of the whole operation.
Conclusions of the study were, that Quality Assurance as integral part of the project needs more
emphasis. The preparation of adequate guidelines in a kind of handbook or checklist could be an
important aid to improve the performance of soil vapor extraction systems. In Germany they are working
on these guidelines.
Validation should not only after the project being an issue. Especially during operation validation tools
can provide the necessary information to modify the system and to adapt operation.
1.2. Surfactant/Cosolvent Flushing- Leland Vane
Validation of the performance of surfactant and cosolvent flushing is complicated, due to the complicated
processes in subsoil. Although in many cases used, it is clear that groundwater monitoring is not the only
and right validation tool. Concentrations in groundwater do not show the overall impact of the desorbing
or mobilizing effect of the adsorbed contaminants on soil particles. No information will be gathered from
the fate of the contaminants still (partly) adsorbed on the soil particles. It only provides evidence of the
mass, diluted in the groundwater. To get more information of the residual bound contaminants on soil
particles other methods are needed. Partitioning interwell tracer tests, PITT, are one of the promising new
techniques. In fact with this technique the fate of the contaminants in the subsoil is "photographed", by
injecting a tracer into the hot spot and recovering it down stream. The recovery curve in the monitoring
wells provides information on mass and location of NAPLs. PITT is fitting as characterization and
validation tool.
But it is clear that to do a good validation a combination of different validation tools is required to
provide evidence, that performance of the remediation system is adequate.
1 8KB, Dutch Foundation for knowledge development and transfer on soil quality management. Buchnerweg 1, Gouda 2800, The
Netherlands. Phone: 31(0)182540690 Telefax: 31(0)182540691 Email: Bert.Satijn@CUR.nl
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
1.3 Validation of In Situ Bioremediation by Applying Isotopes- Frank Volkering
Before validation of in situ bioremediation it is required to consider the parameters and criteria used. Next
to the traditional parameters (concentrations in soil and groundwater, mass removal, etc.), last year's new
lines of evidence have been developed, like hydrogen concentrations, DNA/RNA and isotopes.
Microorganisms do prefer to start with the lighter isotopes before cracking the heavier ones, as has been
proven in many laboratories in batch tests. This phenomenon is called fractionating of stable isotopes. In
one of the SKB-projects at the industrial site of DOW Chemicals in the Netherlands this method has been
used successfully to validate the anaerobic degradation of benzene. It is expected that the application of
analysis of stable isotopes will provide in future more possibilities for validation of the complex subsoil
processes.
1.4 In Situ Chemical Oxidation- Robert Siegrist
In situ chemical oxidation is a new emerging technology for the elimination of hot spots. Also for this
technique performance tests and validation tools are badly needed. Given the complex processes dealing
with multiple evidence is needed for validation. Each method is providing us some part of the subsoil
puzzle. One can think of a combination plume load measurements, mass destruction balances, bioassays
and surface geophysics.
Compared to the traditional methods, it seems to be necessary to provide more evidence to prove that the
new remediation system will be successful. But how much certainty do we have to give?
1.5 In Situ Permeable Reactive Barriers- Volker Birke
In Germany there are several experiences with reactive barriers. Reactive barriers are techniques on the
boundary of in situ and ex situ. Validation of the performance is therefore a little bit easier than in case of
the real in situ techniques. Installation of monitoring wells upstream, in the wall and downstream will
provide the information on process conditions, efficiency and side effects. The technology is focused on
an efficient removal of contaminants in the barrier without too much difficulty during exploitation. In
many cases the barrier is designed to accommodate geochemical processes, for example the iron walls to
eliminate the Tri and Per. But the anomaly in the subsoil is promoting biochemical processes, which
easily creates clogging. The performance of active barriers might therefore be endangered due to bacterial
growth in the barrier material or at the interface between soil and barrier.
In Germany the RUBIN network is established to develop and exchange knowledge on active barriers.
1.6 In Situ Remediation of DNAPLS- Arun Gavaskar
DNAPLs are made not to be discovered and not to be removed. This is the conclusion after studying so
many projects on remediation of DNAPLs. The traditional approach of Pump and Treat is seldom
successful. Pump & Treat becomes Pump & Spill due to the ever-lasting emissions from the source area.
But the efficiency of source removal is sometimes disappointing. In sandy soils with new contaminants
and retraceable source, there are possibilities of a removal rate of 90%. But in other cases it reaches up to
60 or 70%. So secondary treatment is normally necessary. It is also useful to realize that mobilizing the
source and partial removing it, creates a situation in which the residue is normally more mobile than
before. Without secondary treatment emissions to the plume will be bigger than before during a certain
period after shaking up the source. The design of treatment system has to be based on a combination of
primary and secondary treatment.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
2. DEVELOPMENTS OF IN SITU TREATMENT
In situ remediation is a young science, only ten years old. The challenge of heterogeneity and complex
biogeochemical processes makes the "remediator" a "geoartist". Site-specific circumstances influence the
performance of techniques heavily. More understanding of processes by proper evaluation and research is
needed. Better combinations of ex situ and in situ might provide solutions. Source boosting and plume
management will be in many cases the right approach: better combinations of different in situ techniques
with the right energy at the right time and place.
The consultants do not have enough knowledge and experience to propose such combinations. The
contractors are normally specialized in one technique and are unable or unwilling to offer the right
combination. This has also to do with the hardware; each technique requires its own system of hardware.
But in future hardware has to be developed in such a way that the same equipment could be used for the
subsequent phases in remediation.
The secondary treatment after partial removal of the source, is taking normally a long period. Therefore
integration of clean up and redevelopment of the location could be thought over.
3. INSTRUMENTS AND GOALS FOR VALIDATION
Validation of in situ processes is based on the understanding of these processes. The available equipment
is not sophisticated enough to provide the wanted evidence in many cases. More sophisticated monitoring
tools are to be developed in the future, like cone penetration tests with specific probes for all relevant
parameters to register the processes. Cheaper tools are needed in order to be able to get better spatial and
time depending information.
Further development of sensors and effect related monitoring (bioassays) is important. But also the link to
legislation should not be forgotten. Legislation is mainly based on concentrations, although risk based
guidelines are becoming more and more important.
All these wishes do require quite some research funds. The economic developments and the political
attention for soil quality is as such, that more money for these purposes is not to be expected. Therefore it
is recommended to strengthen the international exchange of knowledge and data. An international
performance database with information on the performance (well documented) of in situ techniques and
methods to validate the performance could contribute to further development despite the recent
developments in world society.
Although it will remain a challenge to be successful as "geoartists", the improvement of in situ
techniques, hand in hand with its validation tools, has to contribute to a more predictable and cost
efficient performance in soil quality management.
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
4. PRESENTATION VISUALS -presented by Bert Satijn
Future developments in validation
of in situ performance, expectations,
instruments & goals
Bert Satijn
SKB, Dutch Foundation for
knowledge development and transfer on soil
quality management
Nato/CX:MSi Special Scssi.m
IJcgc, 10 and 11 September 2001
tu sensor for location risk validatj
Outline of Presentation
• Recommendationsoftoday's
presentations
• Developments of in situ treatment
• Instruments and goals for validation
• Plenary discussion of field experiences and
future developments
Key issues of presentations
^traction Michael Ahi-nhuckuni
"They don't kru »iv wh-iii ihcy nrv tluinj
Fincfgy-.-..:):111 Mpii..11 as painuiiclvr Tor
Qu^iIJty HKSurniicf.' .mj guiJelmvH iuv i
•i -II.I.M • H nni onJv ftficrv«uds bui osn
Surfactant/co8o[vcnt Hushing Lfiiind Vane
Developments of in situ treatment
• More understanding of processes by
proper evaluation and research
• Better combinations of ex situ and in situ
- source boosting and plume management
• Better combinations of different in situ
techniques
- the right energy at (he right time and place
• Integration of clean up and
redevelopment
Key issues of presentations^)
Volker liirke
prt>cc)MM:« in the will might cmile dogging
In situ remediation of DNAPlj* Arun Ciitvaskar
u-tn il and iipplicd rt-r.e.irch in biodegradiii
122
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Research on biodegradation
Instruments and goals for validation
• More sophisticated monitoring tools
— Cone penetration test with specific probes
• more psifanieiers
• cheaper
• 3D information
- further development of sensors and effect
related monitoring (bioessays) including link
to legislation
" International Performance Database
Developments of in situ treatment (2)
More realistic goals by authorities and
Better understanding of risk reduction
related to cost efficiency
Better balance for uncertainties
Function related risk criteria fitted on
location scale (Soliuni 3)
Instruments and goals for
validation (2)
• Validation is an integral part of in situ
technology
• Validation protocol is determined during
planning phase
• Protocol is not denying heterogeneity
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Concluding Remarks
• Policy development
• Technology of in situ treatment
• Monitoring devices
• Validation strategies
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
COUNTRY REPRESENTATIVES
Directors
Stephen C. James (Co-Director)
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
26 Martin Luther King Dr.
Cincinnati, OH 45268
United States
tel: 513-569-7877
fax:513-569-7680
e-mail: iames.steve@epa.gov
Walter W. Kovalick, Jr. (Co-Director)
Technology Innovation Office
U.S. Environmental Protection Agency
1200 Pennsylvania Ave, NW (5102G)
Washington, DC 20460
United States
tel: 703-603-9910
fax: 703-603-9135
e-mail: kovalick.walter@epa.gov
Co-Pilot Directors
Volker Franzius
Umweltbundesamt
Bismarckplatz 1
D-14193 Berlin
Germany
tel: 49/30-8903-2496
fax: 49/30-8903-2285 or -2103
e-mail: volker.franzius@iuba.de
H. Johan van Veen
TNO/MEP
P.O. Box 342
7800 AN Apeldoorn
The Netherlands
tel: 31/555-493922
fax: 31/555-493921
e-mail: h.i.vanveen@mep.tno.nl
Country Representatives
Anahit Aleksandryan
Ministry of Nature Protection
35, Moskovyan Strasse
375002 Yerevan
Armenia
tel: +37/42-538-838
fax:+3 7/42-151-938
e-mail: goga@arminco.com
Harald Kasamas
Bundesministerium fur Landwirtschaft und
Forstwirtschaft, Umwelt und
Wasserwirtschaft (BMLFUW)
Abteilung VI/3 - Abfallwirtschaft und
Altlastenmanagement
Stubenbastei 5
A-1010 Wien, Osterreich
Austria
tel:+43-1-51522-3449
email: harald.kasamas@bmu.gv.at
Jacqueline Miller
Brussels University
Avenue Jeanne 44
1050 Brussels
Belgium
tel: 32/2-650-3183
fax: 32/2-650-3189
e-mail: jmiller@ulb.ac.be
Lisa Keller
Environmental Technology Advancement
Directorate
Environment Canda - EPS
12th Floor, Place Vincent Massey
Hull, Quebec K1A OH3
Canada
tel: 819/953-9370
fax: 819/953-0509
e-mail: lisa.keller@ec.gc.ca
Jan Krohovsky
Ministry of the Environment
Department of Environmental Damages
Vrsovicka 65
100 10 Prague
Czech Republic
tel: +420/2-6712-2729
fax:+420/2-6731-03 05
e-mail: krhov@env.cz
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Hana Kroova
Czech Ministry of the Environment
Vrsovicka 65
100 10 Prague 10
Czech Republic
tel: 420/2-6712-1111
fax: 420/2-6731-03 05
Kim Dahlstrem
Danish Environmental Protection Agency
Strandgade 29
DK-1401 Copenhagen K
Denmark
tel: +45/3266-0388
fax: 45/3296-1656
e-mail: kda@mst.dk
Ari Seppanen
Ministry of Environment
P.O. Box 399
00121 Helsinki
Finland
tel: +358/9-199-197-15
fax: +358/9-199-196-30
e-mail: ari.seppanen(givyh.fi
Christian Militon
Environmental Impact and Contaminated Sites
Department
French Agency for Environment and Energy
Management (ADEME)
2, square La Fayette
BP406
49004 ANGERS cedex 01
France
tel:(33)-2-41-91-40-51
fax: (33)-2-41-91-40-03
e-mail: Christian. militon@ademe.fir
Andreas Bieber
Federal Ministry for the Environment
Ahrstrasse 20
53175 Bonn
Germany
tel: 49/228-305-305-3431
fax: 49/228-305-305-2396
e-mail: bieber.andreas@bmu.de
Anthimos Xenidis
National Technical University Athens
52 Themidos Street
15124 Athens
Greece
tel: 30/1-772-2043
fax: 30/1-772-2168
e-mail: axen@central.ntua.gr
Pal Varga
National Authority for the Environment
F6 u.44
H-1011 Budapest
Hungary
tel: 36/1-346-8310
fax: 36/1-315-0812
e-mail: vargap@mail5.ktm.hu
Matthew Crowe
Environmental Management and Planning
Division
Environmental Protection Agency
P.O. Box 3000
Johnstown Castle Estate
County Wexford
Ireland
tel: +353 53 60600
fax: +353 53 60699
e-mail: m.crowe@epa.ie
Francesca Quercia
ANPA - Agenzia Nazionale per la Protezione
dell'Ambiente
Via V. Brancati 48
I-00144 Rome
Italy
tel. 39/6-5007-2510
fax 3 9/6-5 007-25 31
e-mail: quercia@anpa.it
Masaaki Hosomi
Tokyo University of Agriculture and
Technology
2-24-16 Nakamachi
Tokyo 184-8588
Japan
tel:+81-42-388-7070
fax:+81-42-381-4201
e-mail: hosomi@cc.tuat.ac.jp
Oskars Kupcis
Ministry of Environmental Protection and
Regional Development
Peldu Str. 25
LV-1494 Riga
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Latvia
tel: +371/7-026-412
fax:+371/7-228-751
e-mail: oskars@varam.gov.lv
Kestutis Kadunas
Hydrogeological Division, Geological Survey
Konarskio 35
2600 Vilnius
Lithuania
tel 370/2-236-272
fax: 370/2-336-156
e-mail: kestutis.kadunas@lgt.lt
Bj0rn Bj0rnstad
Norwegian Pollution Control Authority
P.O. Box 8100 Dep
N-0032 Oslo
Norway
tel: 47/22-257-3664
fax: 47/22-267-6706
e-mail: bjorn.bjornstad@sft.telemax.no
Marco Estrela
Institute de Soldadura e Qualidade
Centre de Tecnologias Ambientais
Tagus Park
EC Oeiras - 2781-951 Oeiras
Portugal
tel:+351/21-422 90 05
fax:+351/21-422 81 04
e-mail: maestrela@isq.pt
loan Gherhes
EPA Baia Mare
I/A Iza Street
4800 Baia Mare
Romania
tel: 40/4-62-276-304
fax: 40/4-62-275-222
e-mail: epa@multinet.ro
Branko Druzina
Institute of Public Health
Trubarjeva 2-Post Box 260
6100 Ljubljana
Slovenia
tel: 386/61-313-276
fax: 386/61-323-955
e-mail: branko.druzina@gov.si
Pablo Higueras
University of Castilla-La Mancha
Almaden School of Mines
Plaza Manuel Meca, 1
13400 Almaden (Ciudad Real)
Spain
tel: +34 926441898 (work in Puertollano)
fax: +34 926421984
e-mail: phigueras@igem-al.uclm.es
Ingrid Hasselsten
Swedish Environmental Protection Agency
Blekholmsterrassen 36
S-106 48 Stockholm
Sweden
tel: 46/8-698-1179
fax: 46/8-698-1222
e-mail: inh@environ.se
Bernard Hammer
BUWAL
3003 Bern
Switzerland
tel: 41/31-322-9307
fax: 41/31-382-1456
e-mail: bernard.hammer@buwal.admin.ch
Kahraman Unlii
Depratment of Environmental Engineering
Middle East Technical University
Inonii Bulvari
06531 Ankara
Turkey
tel: 90-312-210-1000
fax:90-312-210-1260
e-mail: kunlu@metu.edu.tr
Theresa Kearney
Environment Agency
National Groundwater and Contaminated Land
Centre
Olton Court 10 Warwick Road, Olton
Solihul, West Midlands B92 7HX
United Kingdom
tel:+44/121—711-2324
fax:+44/121—711-5925
e-mail: theresa.kearney@environment
agencv.gov.uk
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Performance Verification of In Situ Remediation NATO/CCMS Pilot Project Phase III
ATTENDEES LIST
Michael Altenbockum
Altenbockum & Partner, Geologen
Lathringersrtasse 61
52070 Aachen
Germany
tel: +49/241-4017-462
fax: +49/241-4017-465
e-mail: info@altenbockum.de
Anahit Aleksandryan (c.r.)
Ministry of Nature Protection
35 Moskovyan str.
375002 Yerevan
Republic of Armenia
tel: 37/42-538-838
fax: 37/42151-938
e-mail: goga@arminico.com
Paul M. Beam
U.S. Department of Energy
19901 Germantown Road
Germantown, MD 20874-1290
United States
tel: 301-903-8133
fax: 301-903-3877
e-mail: paul .beam@em.doe.gov
Andreas Bieber (c.r.)
Federal Ministry for the Environment
Ahrstrasse 20
53175 Bonn
Germany
tel: 49/228-305-305-3431
fax: 49/228-305-305-2396
e-mail: bieber.andreas@bmu.de
Harald Burmeier
Fachhochschule North-East Lower Saxony
Department of Civil Engineering
Herbert Meyer Strasse 7
29556 Suderburg
Germany
tel: 49/5103-2000
fax: 49/5103-7863
e-mail: h.burmeier@t-online.de
Jiirgen Busing
European Commission
Rue de la Loi/Wetsraat 200
B-1049 Brussels
Belgium
tel: +32/2-295-5625
fax: +32/2-296-3024
e-mail: Juergen.Buesing@cec.eu.int
Adrian Butler
Imperial College
London SW7 2BU
United Kingdom
tel: +44/207-594-6122
fax: +44/207-594-6124
e-mail: a.butler@ic.ac.uk
Nadim Copty
Bogazici University
Institute of Environmental Sciences
80815Bebek
Turkey
tel: +90/212-358-1500
fax: +90/212-257-5033
e-mail: ncopty@boun.edu.tr
Maria da Conceicao Cunha
ISEC
Quinta da Nora
3030 Coimbra
Portugal
tel:+351239722694
e-mail: mccunha@isec.pt
Pierre Dengis
ISSeP
Rue Olu Leroi 200
B-4000 Liege
Belgium
tel:+32/4—229-8311
fax: +32/4-252-4665
e-mail: p.dengis@inep.be
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Ludo Diels
VITO (Flemish Institute for Technological
Research)
Boeretang 200
2400 - Mol
Belgium
tel: 32/14-33.5l.OO
fax: 32/14-58.05.23
e-mail: leen.bastiaens@vito.be
Victor Dries
OVAM
Kan. De Deckerstraat 22-26
B-2800 Mechelen
Belgium
tel: +32/015-284-490
fax: +32/015-284-407
e-mail: victor.dries@ovam.be
Branko Druzina (c.r.)
Institute of Public Health
Trubarjeva 2-Post Box 260
6100 Ljubljana
Slovenia
tel: 386/1-432-3245
fax: 386/1-232-3955
e-mail: branko.druzina@ivz-rs.si
Vitor Ap. Martins dos Santos
German Research Centre for Biotechnology
Mascheroder Weg 1
D-3 8124 Braunschweig
Germany
tel:+49/5 31-6181-422
fax:+49/531-6181-411
e-mail: vds@gbf.de
Thomas Early
Oak Ridge National Laboratory
Bethel Valley Road 1
P.O. Box 2008
Oak Ridge, TN 37831-6038
United States
tel: 865-574-7726
fax: 865-576-8646
Marco Antonio Medina Estrela
ISQ - Institute de Solidadura E Qualidade
EN 249 - Km 3, Cabanas - Leiao (Tagus Park)
Apartado 119
2781 Oeiras - Codex
Portugal
tel:+351/1-422-8100
fax:+351/1-422-8129
e-mail: maestrela@isq.pt
Michel Foret
Minister for the Environment and Town &
Country Panning
Government Wallon
Place des Celestines 1
B-5000 Namur
Belgium
tel:+32/081-234-111
fax:+32/081-234-122
e-mail: foret@gov.wallonie.be
Volker Franzius
Umweltbundesamt
Bismarckplatz 1
D-14193 Berlin
Germany
tel: 49/30-8903-2496
fax: 49/30-8903-2285 or -2103
e-mail: volker.franzius@uba.de
Arun Gavaskar
Battelle
505 King Avenue
Columbus, Ohio 43201
United States
tel: 614-424-3403
fax: 614-424-3667
loan Gherhes (c.r.)
Mayor's Office
Municipality of Baia Mare
37, Gh. Sincai Street
4800 Baia Mare
Romania
tel: 40/94-206-500
fax: 40/62-212-961
e-mail: igherhes@baiamarecitv.ro
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Philippe Goffin
Member of the Cabinet
Place des Celestines, 1
5000 - Namur
Belgium
tel: 32/81-234.111
fax: 32/81-234.122
e-mail: foret@gov.wallonie.be
Neil C.C. Gray
AstraZeneca Canada Inc.
2101HadwenRoad
Mississauga, Ontario
L5K 2L3
Canada
tel: (905) 403-2748
fax: (905) 823-0047
e-mail: Neil.Gray@astrazeneca.com
Henri Halen
SPAQuE (Public Society for the Quality of
Environment) - Wallonia
Boulevard d'Avroy, 38/6
4000 Liege
Belgium
tel: 32/4-220.94.82
fax: 32/4-221.40.43
e-mail: h.halen@spaque.be
Pablo Higueras (c.r.)
University of Castilla-La Mancha
Almaden School of Mines
Plaza Manuel Meca, 1
13400 Almaden (Ciudad Real)
Spain
tel: +34 926441898 (work in Puertollano)
fax: +34 926421984
e-mail: phigueras@igem-al.uclm.es
Masaaki Hosomi (c.r.)
Tokyo University of Agriculture and
Technology
2-24-16 Nakamachi, Koganei
Tokyo 184
Japan
tel: 81/3-423-887-070
fax: 81/3-423-814-201
e-mail: hosomiigjcc.tuat.ac.ip
Stephen C. James (Co-Director)
U.S. Environmental Protection Agency
26 Martin Luther King Dr.
Cincinnati, OH 45268
United States
tel: 513-569-7877
fax:513-569-7680
e-mail: james.steve@epa.gov
Kestutis Kadunas (c.r.)
Hydrogeological Division, Geological Survey
Konarskio 35
2600 Vilnius
Lithuania
tel 370/2-236-272
fax: 370/2-336-156
e-mail: kestutis.kadunas@lgt.lt
Harald Kasamas (c.r.)
Bundesministerium fur Landwirtschaft und
Forstwirtschaft, Umwelt und
Wasserwirtschaft (BMLFUW)
Abteilung VI/3 - Abfallwirtschaft und
Altlastenmanagement
Stubenbastei 5
A-1010 Wien, Osterreich
Austria
tel:+43-1-51522-3449
email: harald.kasamas@bmu.gv.at
Theresa Kearney (c.r.)
Environment Agency
National Groundwater and Contaminated Land
Centre
Olton Court 10 Warwick Road, Olton
Solihul, West Midlands B92 7HX
United Kingdom
tel:+44/121—711-2324
fax:+44/121—711-5925
e-mail: theresa.kearney@environment-
agency.gov.uk
Oliver Kraft
Altenbockum & Partner, Geologen
Lathringersrtasse 61
52070 Aachen
Germany
tel: +49/241-4017-462
fax: +49/241-4017-465
e-mail: info@altenbockum.de
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Hans-Peter Koschitzky
VEGAS, Research Facility
Chair for Hydraulics and Groundwater,
University of Stuttgart
Pfaffenwaldring 61
D - 70550 Stuttgart
Germany
tel: 49/711-685-4717
fax: 49/711-685-7020
e-mail: hans-peter.koschitzky@iws.uni-
stuttgart.de
Walter W. Kovalick, Jr. (Co-Director)
Technology Innovation Office
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, N.W. (5102G)
Washington, DC 20460
United States
tel: 703-603-9910
fax: 703-603-9135
e-mail: kovalick.walter@epa.gov
Jan Krohovsky (c.r.)
Ministry of the Environment
Department of Environmental Damages
Vrsovicka 65
100 10 Prague
Czech Republic
tel: +420/2-6712-2729
fax:+420/2-6731-03 05
e-mail: krhov@env.cz
Oskars Kupcis (c.r.)
Ministry of Environmental Protection and
Regional Development
Peldu Str. 25
LV-1494 Riga
Latvia
tel: +371/7-026-412
fax:+371/7-228-751
e-mail: oskars@varam.gov.lv
Louis Maraite
Government Wallon
Place des Celestines 1
B-5000 Namur
Belgium
tel:+32/081-234-111
fax:+32/081-234-122
e-mail: foret@gov.wallonie.be
Peter Merkel
SAFIRA
Lehrstuhl fur Angewandte Geologie
Sigwartstr. 10
D-72076 Tubingen
Germany
tel: +49/7071-297-5041
fax: +49/7071-5059
e-mail: peter.merkel@uni-tuegingen.de
Jochen Michels
DECHEMA
Theodor-Heuss-Allee 25
60486 Frankfurt am Main
Germany
tel: 49-69-75 64-157
fax: 49-69-75 64-388
e-mail: michels@dechema.de
Jacqueline Miller (c.r.)
Brussels University
Avenue Jeanne 44
1050 Brussels
Belgium
tel: 32/2-650-3183
fax: 32/2-650-3189
e-mail: jmiller@ulb.ac.be
Christian Militon (c.r.)
Environmental Impact and Contaminated Sites
Department
French Agency for Environment and Energy
Management (ADEME)
2, square La Fayette
BP406
49004 ANGERS cedex 01 FRANCE
tel:(33)-2-41-91-40-51
fax: (33)-2-41-91-40-03
e-mail: Christian.militon@ademe.fir
Marylene Moutier
SPAQUE
Boulevard d'Avroy, 38
4000 Liege
Belgium
Tel:+32/4-220-9411
Fax: +32/4-221-4043
e-mail: m.moutier@spaque.be
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Francesca Quercia (c.r.)
ANPA - Agenzia Nazionale per la Protezione
dell'Ambiente
Via V. Brancati 48
I-00144 Rome
Italy
tel. 39/6-5007-2510
fax 3 9/6-5 007-25 31
e-mail quercia@anpa.it
Dominique Ranson
AIG Europe
Kortenberglaan 170
1000 Brussels
Belgium
tel: +32.2.739.92.20
fax: +32.2.740.05.36
e-mail: dominque.ranson(giaig.com
AIG Europe Netherlands
K.P. Van der Mandelelaan 50
NL 3062 MB Rotterdam
The Netherlands
tel:+31.10.453.54.96
fax:+31.10.453.54.01
Hubertus M.C. Satijn
8KB
Buchnerweg 1
P.O. Box420
2800 AK Gouda
Netherlands
tel:+31/182-540-690
fax:+31/182-540-691
e-mail: bertsatijn@nok.nl
Phillippe Scauflaire
SPAQUE
Boulevard d'Avroy, 38
4000 Liege
Belgium
tel:+32/4-220-9411
fax: +32/4-221-4043
e-mail: p.scauflaire@spaque.be
Chris Schuren
TAUW
Handelskade 11
7400 AC Deventer
The Netherlands
tel:+31/570-699-591
fax:+31/570-699-666
e-mail: chs@tauw.nl
Dott. Armando Sechi
Aquater
C.P. 20
61047 San Lorenzo in Campo (PS)
Italy
tel:+39/721-731-345
fax:+3 9/721-731-3 76
e-mail: armando.secdhi@aquater.eni.it
Ari Seppanen (c.r.)
Ministry of Environment
P.O. Box 399
00121 Helsinki
Finland
tel: 358/9-199-197-15
fax: 358/9-199-196-30
e-mail: Ari.Seppanen@vyh.fi
Robert Siegrist
Colorado School of Mines
Environmental Science and Engineering
Division
112CoolbaughHall
Golden, Colorado 80401-1887
United States
tel: 303-273-3490
fax: 303-273-3413
e-mail: siegrist@mines.edu
Phillip Sinclair
Coffey Geosciences Pty Ltd
ACN 056 335 516
ABN 57 056 335 516
16 Church Street
POBox40, KEWVIC3101
Hawthorn, Victoria 3122
Australia
tel: +61/3-9853-3396
fax:+61/3-9853-0189
e-mail: phil_sinclair@coffey.com.au
Kai Steffens
PROBIOTEC GmbH
SchillingsstraBe 333
D 52355 Duren-Giirzenich
Germany
tel: 49/2421-69090
fax: 49/2421-690961
e-mail: steffans@probiotec.de
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Performance Verification of In Situ Remediation
NATO/CCMS Pilot Project Phase III
Jan Svoma
Aquatest a.s.
Geologicka 4
152 00 Prague 5
Czech Republic
tel: 420/2-581-83-80
fax: 420/2-5 81-77-5 8
e-mail: aquatest@aquatest.cz
Kahraman Unlii (c.r.)
Department of Environmental Engineering
Middle East Technical University
Inonii Bulvari
06531 Ankara
Turkey
tel: 90/312-210-5869
fax: 90/312-210-1260
e-mail: kunlu(gjmetu.edu.tr
Katrien Van Den Bruel
IBGE-BIM (Brussels Institute for
Environmental Management)
Gulledelle 100
1200 Brussels
Belgium
tel: 32/2-775.75.17
e-mail: hde@ibgebim.be
Monique Van Den Bulcke
Governement Wallon
Place des Celestines 1
B-5000 Namur
Belgium
tel:+32/081-234-111
fax:+32/081-234-122
e-mail: foret@gov.wallonie.be
Eddy Van Dyck
OVAM (Public Waste Agency of Flanders)
Kan. De Deckerstraat 22-26
2800 Mechelen
Belgium
tel: 32/15-284.284
fax: 32/15-20.32.75
e-mail: evdyck@ovam.be
Leland Vane
U.S. Environmental Protection Agency
26 Martin Luther King Drive
Cincinnati, Ohio 45268
United States
tel: 513-569-7799
fax:513-569-7677
e-mail: vane.lelandigjepa.gov
H. Johan Van Veen (c.r.)
TNO/MEP
P.O. Box 342
7800 AH Apeldoorn
The Netherlands
tel: 31/555-49-3922
fax: 31/555-49-3231
e-mail: h.j..vanveen@mep.tno.nl
John Vijgen
Consultant
Elmevej 14
DK-2840 Holte
Denmark
tel: 45 /45 41 03 21
fax: 45/45 4109 04
e-mail: john.vijgen@get2net.dk
Frank Volkering
TAUW
Handelskade 11
7400 AC Deventer
The Netherlands
tel:+31/570-699-795
fax:+31/570-699-666
e-mail: fvo@tauw.nl
Tony Wakefield
Consulting Engineer
Wakefield House, Little Casterton Road,
Stamford
Lincolnshire PE9 1BE
United Kingdom
tel: +44/1780-757-307
fax:+44/1780-766-313
Terry Walden
BP Oil Europe
Chertsey Road
Sunbury-on-Thames
Middlesex TW16 7LN
United Kingdom
tel: (44) 1932-764794
fax: (44) 1932-764860
e-mail: waldenjt@bp.com
Anthimos Xenidis (c.r.)
National Technical University Athens
52 Themidos Street
15124 Athens
Greece
tel: 30/1-772-2043
fax: 30/1-772-2168
e-mail: axen@central.ntua.gr
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Performance Verification of In Situ Remediation
Mehmet AH Yukselen
Marmara University
Environmental Engineering Department
Goztepe 81040 Istanbul
Turkey
tel: 90/216-348-1369
fax: 90/216-348-0293
email: vukelson@mutek.org.tr
NATO/CCMS Pilot Project Phase III
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NATO/CCMS Pilot Project on Contaminated Land and Groundwater (Phase III) January 2002
PILOT STUDY MISSION
PHASE III C Continuation of NATO/CCMS Pilot Study:
Evaluation of Demonstrated and Emerging Technologies for the Treatment
of Contaminated Land and Groundwater
1. BACKGROUND TO PROPOSED STUDY
The problems of contamination resulting from inappropriate handling of wastes, including accidental
releases, are faced to some extent by all countries. The need for cost-effective technologies to apply to
these problems has resulted in the application of new/innovative technologies and/or new applications of
existing technologies. In many countries, there is increasingly a need to justify specific projects and
explain their broad benefits given the priorities for limited environmental budgets. Thus, the
environmental merit and associated cost-effectiveness of the proposed solution will be important in the
technology selection decision.
Building a knowledge base so that innovative and emerging technologies are identified is the impetus for
the NATO/CCMS Pilot Study on "Evaluation of Demonstrated and Emerging Technologies for the
Treatment of Contaminated Land and Groundwater." Under this current study, new technologies being
developed, demonstrated, and evaluated in the field are discussed. This allows each of the participating
countries to have access to an inventory of applications of individual technologies, which allows each
country to target scarce internal resources at unmet needs for technology development. The technologies
include biological, chemical, physical, containment, solidification/stabilization, and thermal technologies
for both soil and groundwater. This current pilot study draws from an extremely broad representation and
the follow up would work to expand this.
The current study has examined over fifty environmental projects. There were nine fellowships awarded
to the study. A team of pilot study country representatives and fellows is currently preparing an extensive
report of the pilot study activities. Numerous presentations and publications reported about the pilot study
activities over the five-year period. In addition to participation from NATO countries, NACC and other
European and Asian-Pacific countries participated. This diverse group promoted an excellent atmosphere
for technology exchange. An extension of the pilot study will provide a platform for continued
discussions in this environmentally challenging arena.
2. PURPOSE AND OBJECTIVES
The United States proposes a follow-up (Phase III) study to the existing NATO/CCMS study titled
"Evaluation of Demonstrated and Emerging Technologies for the Treatment of Contaminated Land and
Groundwater." The focus of Phase III would be the technical approaches for addressing the treatment of
contaminated land and groundwater. This phase would draw on the information presented under the prior
studies and the expertise of the participants from all countries. The output would be summary documents
addressing cleanup problems and the array of currently available and newly emerging technical solutions.
The Phase III study would be technologically orientated and would continue to address technologies.
Issues of sustainability, environmental merit, and cost-effectiveness would be enthusiastically addressed.
Principles of sustainability address the use of our natural resources. Site remediation addresses the
management of our land and water resources. Sustainable development addresses the re-use of
contaminated land instead of the utilization of new land. This appeals to a wide range of interests because
it combines economic development and environmental protection into a single system. The objectives of
the study are to critically evaluate technologies, promote the appropriate use of technologies, use
information technology systems to disseminate the products, and to foster innovative thinking in the area
of contaminated land. International technology verification is another issue that will enable technology
users to be assured of minimal technology performance. This is another important issue concerning use of
innovative technologies. This Phase III study would have the following goals:
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NATO/CCMS Pilot Project on Contaminated Land and Groundwater (Phase III) January 2002
a) In-depth discussions about specific types of contaminated land problems (successes and failures)
and the suggested technical solutions from each country's perspective,
b) Examination of selection criteria for treatment and cleanup technologies for individual projects,
c) Expand mechanisms and channels for technology information transfer, such as the NATO/CCMS
Environmental Clearinghouse System,
d) Examination/identification of innovative technologies, and
e) Examining the sustainable use of remedial technologies looking at the broad environmental
significance of the project, thus the environmental merit and appropriateness of the individual
project.
3. ESTIMATED DURATION
Meetings: November 1997 to May 2002
Completion of final report: June 2003
4. SCOPE OF WORK
First, the Phase III study would enable participating countries to continue to present and exchange
technical information on demonstrated technologies for the cleanup of contaminated land and
groundwater. During the Phase II study, these technical information exchanges benefited both the
countries themselves and technology developers from various countries. This technology information
exchange and assistance to technology developers would therefore continue. Emphasis would be on
making the pilot study information available. Use of existing environmental data systems such as the
NATO/CCMS Environmental Clearinghouse System will be pursued. The study would also pursue the
development of linkages to other international initiatives on contaminated land remediation.
As in the Phase II study, projects would be presented for consideration and, if accepted by other
countries, they would be discussed at the meetings and later documented. Currently, various countries
support development of hazardous waste treatment/cleanup technologies by governmental assistance and
private funds. This part of the study would report on and exchange information of ongoing work in the
development of new technologies in this area. As with the current study, projects would be presented for
consideration and if accepted, fully discussed at the meetings. Individual countries can bring experts to
report on projects that they are conducting. A final report would be prepared on each project or category
of projects (such as thermal, biological, containment, etc.) and compiled as the final study report.
Third, the Phase III study would identify specific contaminated land problems and examine these
problems in depth. The pilot study members would put forth specific problems, which would be
addressed in depth by the pilot study members at the meetings. Thus, a country could present a specific
problem such as contamination at an electronics manufacturing facility, agricultural production, organic
chemical facility, manufactured gas plant, etc. Solutions and technology selection criteria to address these
problems would be developed based on the collaboration of international experts. These discussions
would be extremely beneficial for the newly industrializing countries facing cleanup issues related to
privatization as well as developing countries. Discussions should also focus on the implementation of
incorrect solutions for specific projects. The documentation of these failures and the technical
understanding of why the project failed will be beneficial for those with similar problems. Sustainability,
environmental merit, and cost-benefit aspects would equally be addressed.
Finally, specific area themes for each meeting could be developed. These topics could be addressed in
one-day workshops as part of the CCMS meeting. These topic areas would be selected and developed by
the pilot study participants prior to the meetings. These areas would be excellent venues for expert
speakers and would encourage excellent interchange of ideas.
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NATO/CCMS Pilot Project on Contaminated Land and Groundwater (Phase I
January 2002
5. NON-NATO PARTICIPATION
It is proposed that non-NATO countries be invited to participate or be observers at this NATO/CCMS
Pilot Study. Proposed countries may be Brazil, Japan, and those from Central and Eastern Europe. It is
proposed that the non-NATO countries (Austria, Australia, Sweden, Switzerland, New Zealand, Hungary,
Slovenia, Russian Federation, etc.) participating in Phase II be extended for participation in Phase III of
the pilot study. Continued involvement of Cooperation Partner countries will be pursued.
6. REQUEST FOR PILOT STUDY ESTABLISHMENT
It is requested of the Committee on the Challenges of Modern Society that they approve the establishment
of the Phase III Continuation of the Pilot Study on the Demonstration of Remedial Action Technologies
for Contaminated Land and Groundwater.
Pilot Country:
Lead Organization:
U.S. Directors:
United States of America
U.S. Environmental Protection Agency
Stephen C. James
U.S. Environmental Protection Agency
Office of Research and Development
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
tel: 513-569-7877
fax:513-569-7680
e-mail: iames.steve@iepa.gov
Walter W. Kovalick, Jr., Ph.D.
U.S. Environmental Protection Agency
Technology Innovation Office (5102G)
1200 Pennsylvania Ave, NW
Washington, DC 20460
tel: 703-603-9910
fax: 703-603-9135
e-mail: kovalick.walterigjepa.gov
Participating Countries:
Scheduled Meetings:
Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Ireland, Japan, New Zealand, Norway,
Poland, Portugal, Slovenia, Sweden, Switzerland, The Netherlands, Turkey,
United Kingdom, United States
February 23-27, 1998, in Vienna, Austria
May 9-14, 1999, in Angers, France
June 26-30, 2000, in Wiesbaden, Germany
September 9-14, 2001, in Liege, Belgium
May 5-10, 2002, Rome, Italy
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