&EPA Underground Storage Tank
Research Program
Volume I - Report
Prepared for:
Science Advisory Board
Prepared by:
Risk Reduction Engineering Laboratory and
Environmental Monitoring Systems Laboratory - LV
Office of Research and Development
U.S. Environmental Protection Agency
-------
Underground Storage Tank
Research Program
Volume I - Report
Prepared for
Science Advisory Board
Prepared by
Risk Reduction Engineering Laboratory and
Environmental Monitoring Systems Laboratory - LV
Office of Research and Development
U.S. Environmental Protection Agency
May 1992
-------
CONTENTS
Page
VOLUME 1
FIGURES iv
TABLES iv
1. INTRODUCTION 1-1
2. REGULATORY AND RESEARCH PROGRAM BACKGROUND
2.1 Regulatory History 2-1
2.2 Trends in Research 2-3
2.2.1 ,RREL Research Trends 2-6
2.2.2 EMSL-LV Research Trends 2-11
3. CURRENT AND PLANNED RESEARCH PROGRAM
3.1 RREL Research Program: Site Assessment and Corrective Action 3-1
3.1.1 RREL Site Assessment: Past, Current and Future Research 3-3
3.1.1.1 Assessment of tank system for regulatory development .. 3-6
3.1.1.2 Assessment of tank system for compliance support 3-7
3.1.13 Improved technologies for assessing tank systems 3-8
3.1.1.4 Aboveground storage tanks 3-11
3.1.1.5 Preliminary data analysis (Loci Conceptual Model) 3-11
3.1.2 RREL Corrective Action: Past, Current and Future Research .... 3-14
3.1.2.1 Technology screening 3-16
3.1.2.2 Technology development and evaluation 3-20
low density nonaqueous phase liquid removal 3-21
in-situ technologies 3-22
ex-situ technologies 3-26
integrated systems 3-29
3.1.23 New and improved technologies 3-30
3.1.2.4 Fractured rock media 3-33
3.1.2.5 Alternative fuels 3-34
3.2. EMSL-LV Research Program: Site Assessment and Corrective Action ... 3-35
3.2.1 EMSL-LV Site Assessment: Past and Current Research 3-41
3.2.1.1 Methods for sampling for petroleum contaminants 3-41
3.2.1.2 Interpreting monitoring data to estimate contamination .. 3-43
3.2.13 Interpreting data to characterize site hydrogeology 3-45
-------
CONTENTS (continued)
Page
3.2.2 EMSL-LV Site Assessment: Future Research 3-46
3.2.2.1 Carbon Dioxide, Oxygen, Hydrocarbon Sensor 3-47
3.2.2.2 Immunoassay test kits tailored to UST applications 3-47
3.2.23 Improved non-invasive site investigation techniques 3-48
3.2.2.4 Site characterization for fine-grained soils 3-48
3.2.2.5 Site characterization for fractured bedrock 3-49
3.23 EMSL-LV Corrective action: Past and Current Research 3-49
3.23.1 Monitoring to support remediation design 3-49
3.23.2 Monitoring to verify remediation progress 3-52
3.2.4 EMSL-LV Corrective Action: Future Research 3-56
3.2.4.1 Improved monitoring of in-situ air sparging 3-56
3.2.4.2 Improved siting of recovery wells 3-57
3.2.43 Improved feedback on product recovery systems 3-57
3.2.4.4 Improved field screening procedures for SVE 3-57
3.2.4.5 In-situ tests for assessing bioactivity 3-58
4. TECHNOLOGY TRANSFER
4.1 RREL Technology Transfer Program 4-1
4.1.1 . Technology Transfer Tools: Past and Current 4-2
4.1.2 Enhancing Technology Transfer: Future 4-5
4.13 Technology Transfer Accomplishments 4-5
4.13.1 Volumetric leak detection methods evaluation 4-5
4.13.2 Computerized on line information system 4-6
4.133 Pipeline protocol 4-7
4.2 EMSL-LV Technology Transfer Program 4-7
4.2.1 Building New Research Capabilities 4-8
4.2.2 ASTM UST Standards 4-8
4.23 Sponsoring Development of New Tools For Commercialization ... 4-9
4.2.4 Outreach Activities 4-9
4.2.4.1 Tank issue papers 4-9
4.2.4.2 Workshops and presentations at national conferences ... 4-10
4.2.43 Training programs co-sponsored by OUST 4-10
ii
-------
CONTENTS (continued)
VOLUME II
APPENDICES
A Summai^ of Federal UST Regulations Al-4
B Listing of UST Research Program Products
RREL Research Products Bl-8
EMSL-LV Research Products/References B9-21
C Project Descriptions
RREL Projects Cl-34
EMSL-LV Projects C35-45
iii
-------
FIGURES
Number Page
2-1 Corrective Action Activity Through January 1992 2-5
2-2 RREL UST Research Program by Major Research Area 2-7
3-1 Overview of RREL UST R&D Program 3-2
3-2 RREL Site Assessment Research Program 3-4
3-3 RREL Aboveground Storage Tank Research Program 3-12
3-4 Description of Loci Conceptual Model 3-13
3-5 Range of Hydrocarbon Constituents in Different Petroleum
Products Associated with Corrective Action Systems 3-15
3-6 Overview of RREL Corrective Action Research Program 3-18
3-7 RREL Research in Developing New and Improved
Technologies for Application to LUST Sites 3-32
3-8 EMSL-LV Research Strategy for UST Site Assessment and
Corrective Action Monitoring 3-37
3-9 EMSL-LV Research and Product Development Cycle 3-38
3-10 Application of EMSL-LV Products to Achieve Faster,
Higher Quality UST Cleanups 3-39
3-11 EMSL-LV Products Track Record 3-40
3-12 At Surface Expression of Sparging Flow Pathways 3-53
4-1 Target Audiences for UST Research Products 4-3
TABLES
2-1 RREL UST Research Program Funding (FY85-FY96) 2-8
2-2 EMSL-LV UST Research Program Funding (FY86-93) 2-12
3-1 RREL Projects in Site Assessment 3-5
3-2 RREL Loci-Based Corrective Action Matrix 3-17
3-3 RREL Projects in Corrective Action 3-19
iv
-------
SECTION 1
INTRODUCTION
During the 1950s and 1960s, hundreds of thousands of underground storage tanks
(and aboveground storage tanks) containing petroleum products and hazardous chemicals
were installed. Many of these tanks have either been abandoned or have exceeded their
useful life and are leaking and thereby posing a serious threat to the Nation's surface- and
ground-water supplies as well as to public health and welfare. An alarming series of
releases reported in the late 1970s and early 1980s confirmed this problem and suggested
that the frequency of such incidents might be higher than originally suspected and the
resulting damage to aquifers more severe. In response, the 1984 reauthorization of the
Resource Conservation and Recovery Act (RCRA) mandated that the U.S. Environmental
Protection Agency (EPA) regulate underground tanks used to store motor fuels and
hazardous chemicals.
Three EPA studies were conducted to determine the nature and national scope of the
leaking underground storage tank (UST) problem. The first, Underground Motor Fuel
Storage Tanks: A National Survey, was published in May 1986.1 This survey documented
the results of a tank tightness testing program, which indicated that 35% of the more than
450 nonfarm, motor fuel UST systems surveyed nationwide failed tightness testing. A
second study, Summary of State Reports on Releases From Underground Storage Tanks,
published in August 1986, revealed a continuous increase in the number of releases
reported between 1970 and 1985.2 The third study, Causes of Releases From UST Systems,
was published in December 1987.3 This study concluded that approximately 25% of all
existing UST systems fail the tightness tests when current methods are used. This
translated to as many as a half million leaking USTs nationwide.
Today, more than 137,000 releases from USTs have been confirmed.4 The EPA
estimates that as many as 15 to 20% of the approximately 1.8 million regulated UST
systems nationwide either are leaking or are expected to leak in the near future.5
The environmental threat from leaking tanks has a direct impact on public health
because approximately half of the Nation's drinking water supply comes from ground
water. Approximately 90-95% of the regulated facilities contain motor fuels and
petroleum products; the remainder contain hazardous chemicals. Small quantities of
gasoline released from an underground storage tank can contaminate millions of gallons of
potable ground water with suspected carcinogens such as benzene, etc. The threat from
leaking tanks is not, however, limited to ground water. Leaking petroleum and chemicals
can also contaminate surface waters and contribute to air pollution. In addition, these
products release vapors that can seep into the sewerage systems of homes and businesses
and accumulate to explosive levels.
1-1
-------
In response to the environmental threats posed by leaking USTs, the Agency's Office
of Research and Development (ORD) developed an integrated research program to
advance the state of the art in leak detection and monitoring, leak prevention, and
corrective action technologies for use at these sites. This document presents ORD's
approach. Section 2 introduces the regulatory history of leaking USTs and the history of
ORD's research program. Section 3 describes current and planned research programs for
site assessment and corrective action being conducted at the Environmental Monitoring
Systems Laboratory in Las Vegas (EMSL-LV) and the Risk Reduction Engineering
Laboratory (RREL) in Edison, New Jersey. Section 4 describes how ORD transmits its
UST research results to its clients and the regulated community through a variety of
technology transfer mechanisms. Appendices to this document include a summary of
Federal UST regulations (Appendix A), a listing of major research products (Appendix
B), and a compendium of project descriptions (Appendix C).
References
1. U.S. Environmental Protection Agency. May 1986. Underground Motor Fuel Storage Tanks: A
National Survey. EPA/560/5-86/013.
2. U.S. Environmental Protection Agency. August 1986. Summary of State Reports on Releases from
Underground Storage Tanks. EPA/600/M-86/020.
3. U.S. Environmental Protection Agency. September 1987. Final Report to U5. EPA/OUST -
Causes of Releases from UST Systems. OUST Docket Number UST 2-3-SB-4.
4. U.S. Environmental Protection Agency. December 1991. Strategic Tracking and Results System,
1st Quarter, Fiscal Year 1992.
5. U.S. Environmental Protection Agency. July/August 1991. Superfund, RCRA, and UST: The
Clean-up Threesome. EPA Journal, 17(3): 14.
1-2
-------
SECTION 2
REGULATORY AND RESEARCH PROGRAM BACKGROUND
2.1 REGULATORY HISTORY
The Hazardous and Solid Waste Amendments (HSWA) of 1984 (PL98-616) extend
and strengthen the provisions of the Resource Conservation and Recovery Act (RCRA) of
1976. These Amendments added a new Subtitle I to RCRA-Regulation of Underground
Storage Tanks - which required EPA to develop and implement a new federal regulatory
program for underground storage tanks that contain petroleum products and hazardous
chemicals. Congress directed EPA to set new federal requirements for detecting leaks
from UST systems, assessing sites where leaks had occurred, taking corrective action in
response to a release, and closing tanks to prevent future releases.
After the passage of HSWA, EPA established the Office of Underground Storage
Tanks (OUST) within the Office of Solid Waste and Emergency Response to develop
regulations and to carry out the Act's mandates. The mission of OUST was to define the
problem; to draft rational and enforceable regulations; and to disseminate information on
interpretation of the regulations and on the numerous technologies involved in preventing,
assessing, and correcting environmental damage caused by leaking USTs.
The Office was also charged with the development of guidelines to administer the
Leaking Underground Storage Tank (LUST) Trust Fund established under Section 205 of
the Superfund Amendments and Reauthorization Act (SARA) of 1986 (PL99-499).
Congress set up the $500 million fund, financed by a $0,001 per gallon tax on motor fuels,
to help States pay for corrective actions at sites where no responsible owner or operator
of a leaking tank can be found. The fund was reauthorized under the Omnibus Budget
Act of 1990.
Subtitle I of RCRA defines "underground storage tank" as "any one or combination of
tanks (including underground pipes connected thereto) which is used to contain an
accumulation of regulated substance, and volume of which ... is 10% or more beneath
the surface of the ground." The following table summarized those tanks not currently
under Subtitle I. Although these tanks are either "exempt" or "deferred" from the current
Federal regulations, individual States can, and often do, include some of them under their
own regulatory requirements.
2-1
-------
Excluded by definition
Excluded from regulation
Deferred from regulation
(RCRA Subtitle I)
(40 CFR 280)
(40 CFR 260)
Farm or residential tanks
UST systems holding RCRA
Wastewater treatment tank
<1100 gallons.
Subtitle C hazardous wastes.
systems.
Tanks storing heating oil for use on
Wastewater treatment tanks
UST systems containing
premises.
regulated trider Clean Water
radioactive material
Septic tanks.
Act.
regulated under Atomic
Pipeline facilities regulated by
Systems containing regulated
Energy Act.
Federal or State laws.
substances used in operations.
UST systems that are part
Surface impoundnents, pits, ponds, or
UST system with <100-gallon
of emergency system at
lagoons.
capacity.
facilities regulated by
Storm Mater or wastewater collection
UST systems containing a
Nuclear Regulatory
systems.
de minimis concentration of
Commission.
~
Flow-through process tanks.
regulated sitostances.
Airport hydrant fuel
Traps or gathering lines directly
Emergency spill or overflow
distribution systems.
related to oil or gas operations.
containment UST systems.
UST systems with
Storage tanks above floor in an
underground area.
field-constructed tanks.
The most significant requirements for the UST program are contained in RCRA
Section 9003(c)-(e). Section 9003(c) requires EPA to establish minimum requirements for
all UST system owners and operators to maintain a leak detection system, to maintain
records on that system, to report releases, to take corrective actions in response to a
release, and to close tanks to prevent future releases. Section 9003(d) requires owners
and operators to maintain evidence of financial responsibility for taking corrective action
should a release occur. Under Section 9003(e), EPA must establish performance stan-
dards for new UST systems. The EPA proposed regulations to implement these HSWA
provisions of RCRA on April 17, 1987 (52 FR 12662-12864). Final technical standards for
USTs were promulgated on September 23,1988 (52 FR 37082-37212). A summary of the
final Technical Standards and Corrective Action Requirements for Owners and Operators
of Underground Storage Tanks (40 CFR Part 280) is contained in Appendix A.
OUSTs Regulatory Philosophy
In working with OUST, the client office, RREL and EMSL-LV recognized several
important attributes of the new federal underground storage tank program that influenced
ORD's approach to structuring its UST research program. These important program
characteristics include:
1. Size of the regulated community. The size of the regulated community that would
need to comply with the new underground storage tank rules was larger than for
any of EPA's other regulatory programs, encompassing approximately two million
underground storage tanks located at about 750,000 facilities nationwide.
2. Learning baseline performance; making improvements from this baseline. OUST
believes it is important to learn the baseline performance of all state UST
programs as an effective curb against asking or expecting the impossible from a
fledgling regulatory program. Under this approach, it is important that research
support both incremental improvements to UST programs as well as suggesting
2-2
-------
areas having the greatest potential for making significant breakthroughs in UST
investigations and remediations.
3. Understanding the real work at the customer level. OUST has identified state
UST program staff and UST investigation and remediation consultants as the
principle external customers of the UST program. Consequently, OUST believes it
is essential that the UST research program understand and reflect the needs of
these customers, especially at the "nuts and bolts" operational level of their day to
day work.
4. Customer-Supplier Relationship. OUST has identified its role to Regional EPA
UST programs and state UST programs as being that of a franchiser of technical
information and services. Similarly, OUST regards ORD as a long-term supplier of
UST research expertise to OUST and the EPA Regions.
5. Technology Innovation. During development of the UST regulatory program,
OUST expressed its commitment to structuring its regulatory program to encourage
innovation in the development of technology and also in the delivery of services
(e.g., the provision of leak detection, investigations or remediation services by the
private sector). On several occasions, OUST sought advice from ORD on how to
accomplish this in specific areas of rulemaking.
ORD continues to incorporate these unique characteristics of the UST regulatory
program in establishing its priorities for scarce research budgets and in its design of
projects and deliverables to the client office.
22 TRENDS IN RESEARCH
The overall goals of ORD's Underground Storage Tank Research and Development
Program are to provide technical support to OUST for rulemaking under Subtitle I of
RCRA and for implementation of the provisions of the LUST Trust Fund under
CERCLA. Research responsibilities for the UST Research Program are divided between
the Environmental Monitoring Systems Laboratory (EMSL) and the Risk Reduction Engi-
neering Laboratory (RREL).
As determined by the Office of Research and Development, the mission of EMSL-LV
in support of the Office of Underground Storage Tanks is to: 1) develop protocols for
external monitoring around underground storage tanks, 2) evaluate procedures for
characterizing UST sites to determine the presence of active leaks and the boundaries of
contamination for corrective action purposes, and 3) provide methods to monitor UST
cleanup progress. The mission of RREL is to: 1) identify and evaluate reliable, cost-
effective techniques and equipment for preventing, detecting, and locating leaks in UST
systems, and for cleaning up contamination at leaking UST sites; and 2) provide technical
assistance decision tools on cleanup actions for LUST Trust Fund program guidance and
implementation.
2-3
-------
R&D activities conducted between 1984 and 1988 focused primarily on leak detection.
Leak detection research was a high-priority activity at both RREL and EMSL for two
reasons: 1) available information about leak detection was insufficient to develop
regulatory standards, and 2) reliable methods were needed to find the large number of
tanks and pipelines believed to be leaking. Results from this R&D effort provided the
basis for technically defensible and achievable regulatory standards. In addition, it has
provided data sufficient for industry to design and develop leak detection systems that
meet or exceed regulatory standards for most tank systems.
Federal requirements for leak detection and corrective action at UST sites went into
effect in December 1988 at 750,000 facilities nationwide. Consequently, between late 1988
and 1991, the research focus shifted to regulatory compliance. OUST, RREL, and EMSL
undertook a coordinated research effort to develop and evaluate standard test procedures
for determining the performance of the most common types of leak detection methods.
These standard procedures provided a quantitative means for States (which are
responsible for implementing the regulations) to certify the performance of the leak
detection methods. During this period, a national program for certifying leak detection
methods was begun using leak detection methods demonstrated to comply with the EPA
rules.
As leak detection systems were installed at UST sites, an increasing number of UST
releases were discovered. Figure 2-1 illustrates the rapid rise in UST investigation and
remediation activities since the federal rules for tank management became effective in
December 1988. With this rapid rise in UST activity came a corresponding need from the
regulatory community for research products to assist them in carrying out quicker, cheaper
and higher quality cleanups at leaking UST sites. ORD began shifting resources into site
investigation and corrective action research, particularly for motor fuel and petroleum
product remediation. A systems approach, based on the relationship between research
needs, expected research products, and the customer needs was initiated. Two main
customers were targeted for these research products: (1) the state regulatory staff who
are responsible for overseeing LUST site remediations and (2) the consulting and
contracting community (and indirectly the scientific community) who will be hired by UST
owners and operators to carry out remediations.
Research deliverables have been directed toward developing: (1) methods and
equipment for in-field, real time measurements of contaminant and site characteristics, (2)
improved engineering processes or methods for conducting remediation activity in the
field, or (3) products that enable remediation work to be carried out more quickly and
more cheaply without sacrificing quality, (e.g., a measurement device, a technology
screening methodology, or design and decision support software). Interim products are
also being produced to transfer information to the states, regions and the regulated
community as quickly as possible. Products include a variety of familiar tools to effect
technology transfer; e.g. publications; workshops, seminars, and conferences; state and
regional technical assistance teams; electronic database information systems; cooperative
agreements with academia; Federal Technology Transfer Act (FTTA) agreements, etc.
2-4
-------
140
130
120
I10
Ğr
£100
n
§ 90
o
£ 80
a> 70
^ 60
o
a 50
.o
| 40
z
30
20
10
0
1/89 2/89 3/89 4/89 1/90 2/90 3/90 4/90 1/91 2/91 3/91 4/91 1/92
Quarter/Fiscal Year
Figure 2-1. Corrective Action Activity through January 1992.
(USEPA Strategic Tracking and Results System)
Confirmed
Releases
UST Federal Regulations
Promulgated
Cleanups
Initiated
Cleanups
Completed
2-5
-------
22.1 RREL Research Trends
Figure 2-2 graphically depicts RREL's UST program by major research area beginning
in fiscal year 1985 and extending out to fiscal year 1996. The development and future
direction of research within these areas are presented in Sections 3 and 4 and supported
with detailed project descriptions in Appendix C. Table 2-1 summarizes the extramural
resources allocated for fiscal years 1985 through 1992 and proposed for fiscal year 1993.
The figures indicated for fiscal years 1994 through 1996 do not represent any formal
budget at this time; however, they are based upon realistic estimates of research needs
identified and described herein to accomplish the goals of the program.
FY85 through FY89 - From FY85 through FY89, the focus of RREL's research was
on identifying the state-of-the-art and developing criteria for assessing the integrity of tank
systems. As shown in Table 2-1, over 80% of the average annual funding during this
period was devoted to this program area, primarily to conduct research to evaluate and
verify the performance of internal leak detection methodologies for tanks and pipelines.
RREL and OUST selected this as a critical area for assisting OUST in drafting policy and
regulations. Although release detection was a main focus of the new UST regulation,
information was insufficient to specify either a performance standard or methods of
detecting leaks. Furthermore, the basic experimental information, necessary to develop
accurate internal leak detection methods was not available. With the completion of
RREL's full-scale UST Test Apparatus [C-3]* these data needs were addressed under
controlled conditions. The fundamentals of testing tanks volumetrically were established
and incorporated into a unique approach to determine and resolve the technological and
engineering issues associated with volumetric leak detection, as well as to define the
current practice of commercially available test methods [C-4].
Early work also focused on an intensive scientific literature search to identify and
define all possible locations of a released motor fuel and/or petroleum product in the
subsurface environment. The purpose of this effort was to increase the understanding of
the larger-scale movement of these contaminants to aid in the selection, design, and
implementation of corrective action techniques. Based on this work a conceptual model
(i.e., "loci" model, described in Section 3) was developed to support a desktop evaluation
of site conditions for screening remediation approaches [C-19].
FY89 through FY92 - Following promulgation of the UST regulations in 1988, the
number of reported and confirmed releases from USTs began to dramatically outpace the
capabilities and resources to clean up and close out these sites. Accordingly, RREL in
concurrence with OUST shifted its research emphasis to provide faster and more cost-
effective approaches to site remediation. Efforts to locate the sources of small leaks in
UST systems more accurately, especially in pressurized systems, were initiated [C-6]. A
new methodology for selecting cleanup technologies at LUST sites was developed [C-19].
Technologies such as soil vapor extraction (SVE) [C-22], soil washing [C-25], thermal
desorption [C-26], and soil reuse [C-28] were investigated. More recently, SVE coupled
with other components such as air sparging and biotreatment [C-24] has been investigated
"C" numbers in brackets refer to page numbers of project descriptions in Appendix C.
2-6
-------
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
System Integrity
Leak Detection Methods Evaluation ATO Evaluation
Leak Prevention/Leak Detection/Leak Location
Protocol (or Evaluating Pipeline Leak Detection Methods
1 * 1 1 Leak Detection
tn Chemical US Tfc
All Tr ~ I
t Detection Methods Review US T Teat Apparatus
4-
I
I
Acoustic Techniques tor
Locating Leaks in Pressurized Pipeline
Tank System Assessment
Leak Detection tn Large US7*
Leak Detection for AAematlve Fuels
Loci Conceptual
Model
Technology
Screening
Experts Workshop
lo Technology Screening
Loci Oocument
Saturated Zone Cleanup Technology Screening Document
Field Evaluation
Studies on Kinetics
s
<
e
a
%
Ex Situ
Technologies
To Integrated Systems
Unsaturated Zone Treatment Technology S&lectton Document
Scientific Database
Consolidated Methodology Scisntrttc Database Handbook
Liquid Product
Removal
Engineering Manual
Field operating Procedure
System
Field Evaluation Experts Workshop Reference Handbook
In Situ
Technologies
Soil Vapor Extraction (SVE)
I ^ To SVE-Ar Spargtng-
SVE-Air Sparging-Bioventing
Assessment Document Field Evaluation Engineering Design Manual
_sL. To Integrated
T f"
sap
£T
Bench Study
J
§1
Outdance Document for Pet/oleum
~ 1
Assessment of Surtmctants/Fleld Evaluation Application Handbook
Experts Wori&hop I
I ~ | I
Thermal Desorpiion
Guidance Document for Nonpetroieum Field Evaluation Application Handbook
Bio-Oxidation
Assessment £> cted Studiea
Integrated
Systems
Field Evaluation
Assessment Document
Field Evaluation
Newly Developed
Technologies
Selected Technologies
PUot Scale StudI
Technology Transfer
Assistance to Rcaions mul Suites
Figure 2-2. RREL UST Research Program by Major Research Area.
-------
Table 2-1. RREL UST Research Program Funding (FY85-FY96)a
FY85-FY89
(Avg Annual)
FY90
FY91
FY92
FY93b
FY94-FY96C
(Avg Annual)
$K
%
Total
$K
%
Total
$K
%
Total
$K
%
Total
$K
%
Total
$K
%
Total
Site Assessment
880
81
410
39
295
29
250
21
350
23
500
25
Leak Detection
Leak Location
Loci Conceptual Model
Corrective Action
150
14
540
52
590
58
870
74
1150
75
1500
75
Technology Screening
Technology
Development/Evaluation
Technology Transfer
50d
5
100d
9
130d
13
50d
5
50d
2
e
(15)*
1080
100
1050
100
1015
100
1170
100
1550
100
2000
100
a Resources indicated are operational resources and represent the total of V101 and D109 funding sources
b Proposed extramural resources
c Estimated resources based upon research needs identified to accomplish program goals
d Funding indicated is entirely for COLIS, which started in FY87. Other technology transfer needs have been satisfied within
the resources assigned to each project.
0 It is anticipated that COLIS will be incorporated into ATTIC and primarily funded by another source.
' A commitment of at least 15% of total resources will be made to implement a more aggressive technology transfer
program.
-------
as an integrated systems approach to cleaning up LUST sites. Funding for corrective
action research increased proportionally from an average of $ 150,000 (14% of the total)
during the period FY85 to FY89 to an average of $ 667,000 (61% of the total) in FY90 to
FY92.
FY92 through FY96 - RREL has designed its UST Research Program based on a
budget of $12 million in FY92, a proposed $1.5 million budget in FY93, and an estimated
annual budget of $2.0 million through FY96. The primary emphasis over the next 5 years
will continue to be in corrective action research with approximately 75% of total projected
research funding directed toward this area (Table 2-1). The focus will be in areas
considered to have the greatest potential for making significant progress in remediating
leaking UST sites. RREL feels that there is a limited window of opportunity for research
to make a difference in reducing the already large and increasing number of leaking UST
sites. Increased research is required now to raise the confidence level associated with
using new and improved technologies which have the potential for reducing the time and
total cost of remediation without sacrificing quality.
The earlier work in identifying and defining the location of contaminants in the
subsurface environment established the foundation for most of the planned site-directed
corrective action research. Future efforts will include an updated review of the scientific
literature and a refinement of this earlier work through a series of scientific research
studies [C-20]. Work in SVE will continue with emphasis on enhancing this technology
and integrating it with other system components such as air sparging and bioventing [C-23,
C-24, C-29]. Research on improved product-removal techniques for light nonaqueous-
phase liquids will be conducted and ultimately integrated into a systems approach to
corrective action [C-21, C-29]. Ex-situ treatment technologies such as thermal desorption
[C-26] and biological treatment in soil piles [C-27] will be investigated. Other technologies
such as steam stripping, radio frequency heating, soil flushing, ozone oxidation, and solvent
extraction will be screened for their application to UST sites, and those that appear to be
the most promising will be selected for further development and evaluation [C-30]. A
major research effort will also be conducted in the area of remediating contamination in
fractured rock media [C-31] and at sites contaminated with alternative fuels [C-32].
RREL's system integrity program (leak prevention, detection, and location) has been
restructured into small, highly technical research projects to specifically satisfy the
compliance needs of the regulated community that are not being addressed by the
industry; e.g. "large" tanks, USTs containing chemicals, double-walled tanks and pipelines,
etc. [C-9 through C-14]. New and improved techniques for determining whether the
system is leaking or is about to leak, and, if a leak is detected, for determining its location
in the system will also be developed and evaluated. RREL has identified a common
technology that addresses most of the needs in these areas, i.e., passive-acoustics.
Research efforts in the application of this technology are highly desirable because passive-
acoustic techniques are noninvasive, nondestructive, and have untapped performance
potential [C-15 through C-18]. Passive acoustic detection techniques are also amenable to
aboveground storage tanks (ASTs). Leak detection and prevention measures for ASTs
are deferred under the present UST regulations; however, the Spills Prevention, Control,
and Countermeasures Act (SPCC), which covers releases from ASTs, is currently
2-9
-------
undergoing revision and is considering leak detection requirements for inclusion in the
proposed rule changes. The regulatory standards for testing ASTs are quite inconsistent
with those for testing USTs. RREL has identified a research program area to address
these inconsistencies using passive acoustic technology [C-34].
Technology Transfer - Technology transfer has been an important and integral
element of all RREL activities. In most cases, technology transfer has been accomplished
within the scope of each project using the familiar tools of publications, workshops,
seminars, conferences, videos, State and Regional technical assistance and training
programs, etc. To date RREL has conducted several dozen major research projects
(Appendix C) and developed almost 100 associated products (Appendix B).
Of particular note under Technology Transfer is RREL's Computerized On-Line
Information System (COLIS) [C-33]. COLIS is an information system comprised of
several databases that contain case histories information on over 175 cleanup actions at
petroleum-contaminated LUST sites (and hazardous waste sites); treatability data on
alternative treatment technologies for removal of contaminants from liquid and solid
wastes; technical information from EPA's Superfund Innovative Technology Evaluation
(SITE) Program; and a computerized library system that allows retrieval of technical
publications on UST and hazardous waste issues. The system can be accessed by the UST
user community nationwide through office personal computers. The system was
developed in 1987 and has been funded on an annual basis to maintain a continuous
source of information, and to update and expand its capabilities. Future plans are to
incorporate COLIS into EPA's National Alternative Treatment Technology Information
Center (ATTIC).
Also of note is RREL's increased activity in site-directed research and in providing
technical and quality control support to EPA Regions and states for the planning, design,
and field evaluation of innovative technologies at actual LUST sites. Regions and states
are hesitant to use these new technologies because of the lack of engineering design
information and substantiated performance data to support their use. RREL is currently
involved in several Regional innovative technology demonstration projects and is
developing "model/generic" Quality Assurance Project Plans for the evaluation of such
technologies as SVE-air sparging, soil mound bioremediation, and thermal desorption. All
field activities will be analyzed and documented (and distributed using various technology
transfer tools) including system operation and maintenance; problems encountered; and
system performance. RREL is pursuing similar site-related research projects with other
Federal Agencies (DOD, DOE, DOT) through Interagency Agreements, and with private
industry through Federal Technology Transfer Act (FTTA) Agreements. By taking
advantage of these situations, RREL is able to leverage its resources to obtain reliable
"real-world" data on how these technologies work and on their application and limitations.
A comprehensive technology transfer approach has been designed to identify, reach,
and inform the diverse UST user community. Because technology transfer is vital to the
ultimate success of RREL's research program, a more aggressive approach will be devoted
to this area over the next 5 years. The programmatic approach will incorporate
technology transfer from the onset of each research project and will include the
2-10
-------
identification of the end users and their involvement in the planning and progress of
research projects; and the development of useful and timely research products that are
better matched to the target audience.
222 EMSL-LV Research Trends
Figure 2-3 summarizes the allocation of EMSL-LVs UST research budget for fiscal
years 1986 through 1992 and the proposed budget for fiscal year 1993. The top graph
shows the total amount of funding received for extramural research. The subsequent
graphs show the approximate allocation of the total budget, both in absolute dollars and
relative percent, for each of the major research categories: leak detection; site assessment
and characterization; and remediation progress monitoring.
External Leak Detection Research Objectives
At the outset of the UST research program, EMSL-LV and OUST selected the
development and testing of external leak detection systems as a critical research area for
assisting OUST in drafting policy and regulations for the new UST regulatory program.
EMSL-LV designed its leak detection research program to answer three major objectives:
1. To describe the variety of external leak detection devices then currently available
and to report their performance.
2. To determine the physical and chemical processes controlling the feasibility of using
vapor detectors and ground water monitoring as external leak detection methods.
3. To establish a protocol for quantitatively describing the key performance attributes
of external vapor detection devices as the basis for encouraging private sector
development of new detection methods.
Summary of Major External Leak Detection Projects
EMSL-LV sponsored a survey of vendors of external leak detection devices in
collaboration with Radian. The results of this survey showed that many vapor monitoring
devices were able to detect leaks but could not be calibrated to a specific leak rate,
because the physical barriers such as geology, temperature and moisture content were too
variable. Rapid detection and the low limits of detection that many vapor sensor devices
are capable of measuring, however, has made vapor detection a popular leak detection
method nationwide [B.177].*
In order to examine the theoretical basis for using external leak detection devices,
EMSL-LV sponsored research for modeling the transport of hydrocarbons in the vapor
phase and as dissolved contaminants in ground water. First, numerical models were
developed to quickly identify those UST backfill configurations and placements of vapor
of ground water sensors that suggested the earliest detection of an UST release. These
"B" numbers in brackets refer to specific products/references in Appendix B.
2-11
-------
Table 2-2. EMSL-LV UST Research Program Funding (FY86-FY93)
FY86-FY89
(Avg Annual)
FY90
FY91
FY92
FY93
Request
$K
%
Total
$K
%
Total
$K
%
Total
$K
%
Total
$K
%
Total
Leak Detection
775
66
418
44
195
17
125
12
95
12
Site Assessment
129
14
436
46
600
53
495
50
317
40
Corrective Action
0
0
50
5
295
26
334
33
327
42
Technology Transfer
0
0
50
5
50
4
50
5
50
6
904
100
954
100
1140
100
1004
100
789
100
-------
numerical screening models were then validated within a large physical model. This large-
scale experimental aquifer facility, located at the Oregon Graduate Institute of Technology
and constructed under EMSL-LV sponsorship, has two sand tanks. One tank has
dimensions of 30 ft x 30 ft x 10 ft and is used primarily for studies of vapor transport in
the unsaturated zone. The second tank has dimensions of 70 ft x 30 ft x 15 ft, and
includes a simulated saturated zone that enables control of the ground water gradient
The tank is used for studying hydrocarbon transport in both the unsaturated and saturated
zones.
In order to compare the usefulness of vapor detectors and ground water monitoring
wells to detect UST releases, the modeling scenarios for both the numerical and physical
models compared the speed of hydrocarbon transport as vapors and as dissolved
contaminants to specific areas within the backfill of a tank or within the ground water
zone. The numerical model and the experimental data from the physical model were in
close agreement, and both showed that vapor movement was the fastest mechanism for
gasoline releases. For example, data from the large-scale physical model experiments
showed that vapors moved rapidly through either pea gravel or sandy backfill material and
could be detected at any point in the backfill material within thirty days. These findings
contributed to the subsequent focus within EMSL-LV and within OUST on refining and
improving vapor monitors to provide early detection of leaks.
Based on these findings, EMSL-LV and OUST decided that the technology of leak
detection and the commercialization of new leak detection methods would be best assisted
by developing protocols for quantitatively describing the performance of external vapor
detectors. Performance standards for internal leak detection methods describe a leak rate
per hour within a prescribed confidence level. In contract, EMSL-LV decided that
performance standards for external leak detection methods - with their different mode of
operation - should be expressed in terms of their accuracy, precision, lower detection
limits, response time, specificity to specific compounds, and vulnerability to environmental
interferences. It was the view of EMSL-LV and OUST that providing a protocol for
presenting this information would best encourage new external leak detection capability
within the small, but rapidly increasing leak detection industry.
EMSL-LV is continuing to sponsor focused laboratory investigations into sensor
capabilities for the two "workhorses" of the external vapor detection market: the adsistor
and the Figaro gas sensing devices. These two sensors are the primary components of the
majority of commercially available vapor sensing devices; however, there is little
quantitative information available on their performance. A report describing the detection
limits, response time, specificity, and interferences for these two devices will be published
in Summer 1992. Some of the preliminary information contained in the report has already
been well received at an ASTM symposium on the development of new sensor technology
[C-36, C-38, B.178, B.179].
EMSL completed the external leak detection protocol project with a philosophy that
matched the graduated approach for leak detection regulations being implemented by
OUST. Industry response to this protocol has been good: the protocols are being
followed voluntarily, manufacturers of external leak detection devices find the protocols
2-13
-------
useful for "leveling the manufacturing playing field;" and new methods of external leak
detection are being developed within the private sector using the protocols as guidelines.
Since the federal rules for UST leak detection went into effect in December 1988, the
practice of leak detection has improved and many detection systems continue to be
installed. As the number of leak detection systems placed in service increases, however,
the rate at which previous leaks and ongoing release are being discovered has risen
geometrically. In consultation with OUST, EMSL-LV concluded that the primary
objectives for leak detection have been met and that continuing EMSL-LV research
should focus on determining how to characterize UST sites where leaks had been detected
and how to determine that remediation was progressing as planned. These topics are
described in Section 3 of this document.
2-14
-------
SECTION 3
SITE ASSESSMENT AND CORRECTIVE ACTION:
CURRENT AND PLANNED RESEARCH PROGRAM
This chapter describes the research being carried out by RREL and EMSL-LV on site
assessment and corrective action at UST sites. Site assessment is defined to include those
activities needed to evaluate the integrity of the tank system, to locate leak sources, to
delineate the vertical and horizontal extent of contamination, and to obtain hydrogeologic
and other subsurface data needed to select and design corrective action and/ormonitoring
strategies appropriate to site conditions. Corrective action is defined to include those
activities needed to design, install, operate and evaluate the performance of systems for
remediating contamination in the subsurface environment; to monitor cleanup progress
and to monitor and treat the side-waste streams produced by the remediation.
The mission and expertise within the RREL and the EMSL-LV laboratories address
different aspects of UST investigation and remediation. Accordingly, the research
activities conducted by each laboratory in the areas of site assessment and corrective
action are described separately in this section.
3.1 RREL RESEARCH PROGRAM: SITE ASSESSMENT AND CORRECTIVE ACTION
The mission of RREL's UST Research Program is to identify and evaluate reliable,
cost-effective techniques and equipment for preventing, detecting, and locating leaks in
UST systems, and for cleaning up contamination at leaking UST sites; and to provide
technical assistance decision tools for more reliable and cost effective cleanup technology
selection and site remediation. As shown in Figure 3-1, the research and development
activities are focused within two primary areas: (1) Site Assessment and (2) Corrective
Action.
RREL's Site Assessment work is further divided into assessing the integrity of the tank
system to prevent, detect, and locate leaks and into analyzing available site data to select
and examine applicable remediation alternatives. UST regulators and consultants need to
be able to make reliable and cost-effective determinations of site conditions, including the
condition of the UST system, for more appropriate leak prevention measures and
selection of cleanup technologies, and for more rapid and improved cleanup actions at
sites. These determinations must be supported by a better understanding of the
subsurface environment, properties of petroleum products, and locations of the
contaminants.
RREL recognizes that there is a need to improve the application and effectiveness of
existing and new technologies used in corrective actions. Accordingly, corrective action
3-1
-------
RREL
UST Research and
Development
Technology
Screening
Preliminary
Data Analysis
(Loci Conceptual Model)
Assessment of
Tank Systems
Technology
Development and
Evaluation
Site
Assessment
Corrective
Action
Figure 3-1. Overview of RREL UST Research and Development Program.
3-2
-------
research activities have focused in two broad areas: (1) Technology Screening and, (2)
Technology Development and Evaluation. The purpose of the Technology Screening
research is to determine which of many cleanup technologies may be used to remediate a
release. Inadequate remediations are sometimes experienced because of a limited
understanding of how corrective action technologies work and how they relate to the
characteristics of the contaminant in the subsurface environment. Many of the traditional
technologies used for remediation have been ineffective because they have been applied
to subsurface conditions for which they were not intended. RREL is attempting to
develop a better understanding of the location and movement of a contaminant in the
subsurface environment to be able to improve the selection of the most appropriate
cleanup technology, and to more adequately determine the progress of cleanup operations
and the residual level of contamination after remediation.
Furthermore, in many cases, investigators are designing and implementing cleanup
systems on a trial and error basis, or are relying on cleanup technologies that are
ineffective and/or inappropriate (e.g., groundwater pump and treat, which in many cases
results in further spreading contamination). RREL's Technology Development and
Evaluation research program area is concentrating on developing technical information on
existing and new technologies to promote their application to LUST sites and to improve
their design, installation, and operation for more effective contaminant removal. This
scientific-based structure is used to organize RREL's research activities in both Site
Assessment and Corrective Action.
3.1.1 RREL Site Assessment: Past, Current and Future Research
The Site Assessment activities of RREL's research program (Figure 3-2) specifically
involve the evaluation of the integrity of the tank system to determine whether the system
is leaking or is about to leak, and, if a leak is detected, to determine its location in the
system. The ultimate goals of the program are to detect and locate a leak at the instant
that it develops, to determine the instant when the tank or pipeline is likely to fail, and to
develop new and improved techniques to extend the life of a system. If these goals are
achieved, the life of a tank system could be maximized and the environment would be
suitably protected. Another primary goal of RREL's Site Assessment program is to
develop rapid screening tools for selecting remediation approaches based on available site
information and on a better scientific understanding of the movement and location of
motor fuels and petroleum products in the subsurface environment.
RREL's research projects in the Site Assessment program area from FY85 through
FY96 are shown in Table 3-1. More detailed information on each project (i.e., objectives,
rationale, description of research, planned and completed outputs) is presented in Volume
II, Appendix C. The subtotals from Table 3-1 were used to develop the total RREL
funding history for Table 2-1. The following discussion presents these research activities in
specific timeframes based on the early needs of OUST for technical support for regulatory
development, the subsequent needs of OUST to satisfy the requirements of the regulated
community, the overall need to advance the state of the technology in both under- and
aboveground storage tank systems, and the need to obtain a more complete understanding
of the subsurface environment to select more appropriate remediation approaches.
3-3
-------
Site Assessment
RREL
Technology
Development/
Evaluation
Assessment ot
Tank System
Leak
Wall
Detection
Integnty
Preliminary
Data Analysis
(Loa Conceptual Model)
Leak
Location
Technology
Screening
Corrective
Action
Figure 3-2. RREL Site Assessment Research Program.
3-4
-------
TABLE 3-1. RREL PROJECTS IN SITE ASSESSMENT
PROJECT TITLE
RESOURCES
-------
3.1.1.1
Assessment of Tank System for Regulatory Development (FY85 - FY891
During the period of regulatory development (1985-1988), RREL's efforts were
focused mainly on the integrity of the tank and pipeline system with particular emphasis
on leak detection methods that are attached to or are internal to the UST system. Wall
integrity R&D was limited to a state-of-the-art survey of leak prevention practices [C-l].
A state-of-the-art survey was conducted in 1985 [C-2] to determine what leak
detection methods could be used for testing tanks and what level of performance was
being achieved with current technology. It was found that the performance of these
methods was improperly defined and unknown, and that, of the methods identified, only
two had modest commercial use. To evaluate the performance claims associated with
volumetric methods of testing tanks and pressure testing pipelines, a special test apparatus
for tanks (completed mid-1986) and for pipelines (completed late-1987) was designed and
built in Edison, New Jersey [C-3].
EPA's UST Test Apparatus made it possible to perform full-scale experiments on
tanks and pipelines under the full range of conditions found in the field. The two
underground 8,000-gal tanks that were installed, one fiberglass and one steel, were
representative of those tanks found at retail service stations. Similarly representative were
the two underground 200 ft. pipelines that were constructed, one fiberglass and one steel.
The initial purpose of the tank evaluation [C-4] and pipeline evaluation [C-5]
programs was (1) to specify the performance standards that would be used in the
regulation and (2) to provide the technical information that would allow the development
or modification of systems capable of achieving this minimum level of performance. The
evaluation program produced the following important results and was instrumental in
changing the state-of-the-art in leak detection practices for industry nationwide.
Performance standards were established for tank tightness testing, automatic tank
gauging, pipeline tightness testing, and automatic line leak detectors [Appendix A].
Although none of the methods used to test tanks and pipeline systems was
achieving the level of performance needed to meet these regulatory standards, the
experimental program demonstrated that through simple protocol changes their
performance could be greatly enhanced. The experimental results and models
necessary to make or justify these changes were provided in a variety of technical
reports, papers, and brochures [B.l, B3-B.10].
A methodology was developed by which the performance of any given leak
detection method could be specified and evaluated.
Methods of compensating for the thermal expansion and contraction of the product
in the tanks and pipelines were developed and evaluated. Based on these, a set of
rules was developed, which, when implemented properly during a test of a tank or
pipeline, would ensure that the leak detection system being used met the EPA
performance standards. The evaluation program showed that it was possible to
3-6
-------
reliably test the kinds of tanks (8,000 to 10,000 gal) and pipelines (2-in diameter)
normally found at retail service stations and private industrial storage facilities. An
extensive list of research publications was produced to describe this work.
(Appendix B).
3.1.1.2 Assessment of Tank System for Compliance Support (FY89-FY96)
RREL's research program in Site Assessment shifted emphasis in 1989 with the
promulgation of the Federal UST regulations. System integrity research was restructured
to assist OUST in addressing the technical needs of the regulated community whose goal
was to achieve compliance with the leak detection and leak prevention regulatory
standards. A series of small but highly technical research projects were identified and
initiated. There is a high payoff for these projects, because it has been demonstrated that
technology transfer has been particularly effective in this area and the regulated
community has been unwilling to make the necessary investment to obtain this type of
information. The regulated community will use this type of information directly in the
development and selection of better methods to use in complying with the regulation.
From FY89 to FY91 RREL completed several projects addressing the assessment of
the tank system for compliance support. A protocol was developed for evaluating the
performance of pipeline leak detection systems to document and certify whether these
systems meet the minimum Federal regulatory requirements [C-6]. A project was
conducted to identify the types of chemicals being stored in USTs, (also covered by the
regulations) and the impacts of their properties on the ability of leak detection
technologies developed for fuel storage tanks to perform satisfactorily in USTs containing
chemicals [C-10]. Federal regulations also address removing USTs from service. A key
concern in UST closure activities is the manner and extent of tank cleaning that is
appropriate and feasible when removing a tank. A project was conducted to obtain a
technical understanding of UST residuals at closure: their origins, physical/chemical
properties and ease of removal by different cleaning methods [C-7]. The inspection of
USTs is also an integral part of the regulations. Another project evaluated existing
inspection procedures and equipment for identifying weaknesses in tank walls, the
presence of corrosion, the quality of lining materials, and the suitability of cleaning
techniques [C-8].
Current and Future activity in assessing the tank system for compliance support will
continue with the small, highly technical research projects to support the needs of the
regulated community. Earlier work at the UST Test Apparatus was conducted on 8,000-
gal tanks (representative of a typical gasoline station). There is a large population of
tanks with capacities much greater than 8,000 gal (e.g., 50,000 gal) that are also covered
by the Federal regulations. It was not known whether or how to meet the tank tightness
regulatory requirements for this important portion of the tank population. A research
project was initiated to address these objectives [C-9]. A set of rules has been developed
for testing in these larger tanks; however, further work is required to evaluate these rules
in the field and to develop and validate a procedure to extrapolate the performance of a
detection method evaluated in one tank to a larger tank. In addition, efforts will be
initiated in the following areas:
3-7
-------
Leak Detection in Small Tanks [C-ll]. There are many small tanks such as home-
heating-oil tanks, generally less that 500 gal in capacity, that may be leaking. The
Federal regulation does not require that these tanks be tested for leaks; however,
many of the state regulations do. A simple inexpensive, and reliable leak detection
method needs to be developed and evaluated for testing these tanks.
Evaluation of Interstitial Leak Detection Systems Used in Double-Walled Tanks
and Piping [014]. Many tank owners are replacing their single-walled tanks and
piping with double-walled ones. There are many detection systems that detect
leaks in the interstitial space of double-walled tanks and piping. EPA has not
provided any technical information to this group of tank owners about the
technologies being used for leak detection or how to evaluate their performance.
Impact of Alternative Fuels [013]. Over the next five years alternative fuels will
begin to replace the traditional gasoline and diesel fuels. There is a concern that
existing storage tank systems designed for the traditional motor fuels, especially the
more recently installed fiberglass systems may not be compatible with these newer
type fuels. The accuracy of leak detection systems, which is directly proportional to
the coefficient of thermal expansion of the product, would also have to be
evaluated for these different fuels.
Evaluation of the Effectiveness of Cathodic Protection [012]. The EPA UST
regulation requires that all existing single-walled steel tanks be cathodically
protected before 1998. For most existing tank systems, this means retrofitting.
Both impressed current and anode-cathode approaches are allowed. If the retrofit
is not done properly it can, instead of prolonging the life of a tank, accelerate
corrosion and produce leaks. A systematic experimental investigation needs to be
conducted to determine the effectiveness of both new and retrofitted systems and
to develop guidelines for their implementation.
3.1.13 Technology Development and Evaluation for Improved Assessment of Tank
Systems (FY91-FY96)
The overall objective of this program area is to develop and evaluate new and
improved methods for quick and accurate location of leaks in pipelines; rapid detection of
leaks above and below the surface of the product in tanks or pipelines, without significant
interruptions to dispensing operations; and direct measurement of flaws and defects in the
walls of tanks and pipelines.
RREL's main R&D emphasis in Site Assessment over the past several years has been
to develop and evaluate volumetric methods of leak detection for tanks and pipelines that
can meet or exceed EPA's regulatory requirements. While this goal has been met
successfully, these techniques require 8 to 16 h to complete a test. Methods of leak
detection are required that minimize the interruption to operations without sacrificing the
performance achieved by these previous methods. Tests that can be completed in less
than 1 h will have a significant impact on the regulated community.
3-8
-------
Very little R&D has been devoted to preventing the occurrence of a leak or locating it
once it has occurred. Leaks could be prevented and better maintenance and upgrading
decisions could be made if reliable methods for directly assessing the structural integrity of
a tank or pipeline were available. This would eliminate needless replacement of
structurally sound tanks or pipelines and would direct efforts to those tanks and pipelines
that are unsound so that they could be replaced before they leak. If a leak does occur,
there is a great need to be able to locate its source quickly and accurately without having
to excavate the material above and around a tank or its associated pipelines. For obvious
reasons, this is particularly important in the remediation of pipeline leaks.
RREL has identified a common technology that addresses most of the needs in this
program area. The use of passive-acoustic arrays, whether mounted externally on the wall
of the tank or pipeline or internally in the product or in the ullage space, can address the
leak prevention, detection, and location needs described above. These techniques are
desirable because they are noninvasive, nondestructive, and have untapped performance
potential. A review of commercial products and services shows that passive-acoustics,
which should be effective, are not, because of the lack of understanding of the signal and
noise field, ineffective data collection and signal processing, and less than optimal sensor
configurations. Some commercial companies are beginning to use acoustic techniques for
leak detection, but the listening techniques they are using are over 25 years old, do not
utilize modern signal processing, and have not been sufficiently evaluated to determine
their effectiveness. The technique is being used despite these drawbacks, because tests
can be done quickly, and there is no need to add product before a test. Acoustic
technology can have a significant impact on the industry. It has the potential to replace
volumetric technology, now the most common means of leak detection, and in addition,
address wall integrity and leak location problems that cannot be addressed volumetrically
and for which the available technology is poor or does not exist.
Sufficient background work has been completed recently by the EPA and the
American Petroleum Institute (API) so that a well defined acoustic measurement program
for tanks and pipelines can be initiated. In general, the same data collection and sensor
systems (software and hardware) can be used for leak location, detection, and wall
integrity measurements. As a consequence, all three measurement areas can be addressed
concurrently. The objective of the research is to determine the signal and noise being
measured, to develop and evaluate the signal processing and sensor configurations
necessary to enhance the signal and reduce the noise, and to demonstrate the utility of
this technique in the field. A series of projects has been identified and addressed on a
priority basis (Table 3-1). At present, the most immediate need is for a technique for
testing the ullage of a partially filled tank and for finding the location of a leak in long
underground pipelines. Because of the complexity of the measurement, an initial
assessment will be conducted on the applicability of adapting acoustic emission methods
for measuring wall defects.
Acoustic Techniques for Locating Leaks in Pipelines [C-15]. In FY 1991, RREL
initiated a research effort to investigate the use of passive-acoustic location
techniques for locating leaks in underground pressurized pipelines containing
gasoline (such as those found at retail service station). Results indicated that with
3-9
-------
the use of advanced signal processing algorithms, this technique was better by a
factor of over 100 than conventional methods in finding the smallest locatable leak.
Additional efforts are planned to determine the smallest locatable leaks as a
function of line length, fuel type, and pipeline material. Once the basic
methodology has been developed and its performance evaluated, Held
demonstrations will be conducted to evaluate the method's operational utility over
a range of pipeline configurations, including longer length (thousands of feet) and
larger diameter (4 in to 12 in) pipelines such as those found at truck stops, as part
of airport hydrant systems, and in aboveground storage tank terminals.
Develop and Evaluate Ullage Leak Detection Systems [C-16]. There is a trend to
test USTs when they are only partially filled to reduce the total time it takes to
conduct a leak detection test and to eliminate the added expense of delivering
product to overfill the system for a test. In order to test the entire tank system,
two tests are required: one of the liquid level and a second of the ullage space
above the liquid level. Many leak detection vendors are testing the ullage space by
means of a pressure-drop test or an acoustic listening system. Both procedures are
fraught with technical problems, are applicable only under very specific conditions,
and are unvalidated experimentally. Nevertheless, these systems are being
accepted by the regulated community without evaluation. Technical information is
urgently required to determine whether these techniques meet regulatory standards.
The objective of this project is to evaluate ullage testing procedures and provide a
set of testing rules for each of several methods that will meet the performance
standards in the regulation. The short-term goal of this work is to facilitate
compliance with the regulation, and the long-term goal is to develop acoustic
methods with general application to any type of tank system.
Acoustic Techniques for Rapidly Detecting Leaks in Tanks or Pipelines [C-17].
Current leak detection systems, if used correctly, require long waiting periods to
accurately conduct tests, and therefore, seriously impact normal operations.
Testing mistakes occur when the required waiting periods are not observed. There
is a need to minimize the down-time that these waiting periods entail, so that
financial losses associated with a test can be minimized. The overall objective of
this work is to develop and evaluate the performance of a method that can be used
to test a tank or pipeline in under 1 h without interruption of dispensing
operations. Passive-acoustic systems can perform such tests; development and
verification of the performance of these systems is required.
Techniques for Estimating the Structural Integrity of UST Systems [C-18]. A
significant environmental benefit could be obtained if the tank owner could directly
assess the structural integrity of a tank system. Cost effective and environmentally
safe decisions could be made to upgrade or replace a system that was in danger of
failing. All of the commonly used methods to measure thickness or material flaws
and cracks require that the tank be taken out of service for the measurements.
These methods are typically used on aboveground storage tanks where access to
the tank walls and floor is possible. Access to walls of an underground tank is
generally not possible and methods which can be used without attaching sensors to
3-10
-------
the walls are needed. The objective of this project is to develop and evaluate a
method using acoustic emissions to detect material flaws in steel and Fiberglass
underground tanks and pipelines.
3.1.1.4 Aboveground Storage Tanks (ASTs)
Based on RREL's UST activities in leak detection, EPA's Office of Emergency and
Remedial Response (OERR) is discussing a similar research approach (Figure 3-3) to
satisfy the strong technical and regulatory needs associated with aboveground storage
tanks. Leak detection and prevention measures for ASTs are deferred under the present
UST regulations. However, it should be noted that the area of the bottom (or buried)
surface of a moderately sized AST is larger than the total buried area of the largest UST,
and the hydrostatic pressure exerted by the product is 5 to 10 times greater in ASTs than
in USTs. At the current time, EPA's Spill Prevention Control and Countermeasures
(SPCC) Regulations (40 CFR Part 112), which cover releases from ASTs, are being
revised. Research in underground liners for ASTs is presently being done by OERR, but
the problem of leak detection is not being addressed. Current procedures rely on
inspectionwhich requires that the tank be taken out of service, emptied, and cleaned. This
process takes several weeks to several months to complete. The API is in the third phase
of a three phase program to assess the state-of-the-art in leak detection for ASTs. Results
to date show that it is possible to test ASTs for leaks and that additional work is required
to develop standards. The most pressing problem is to evaluate the capability of the
technologies that can be used for leak detection. The API work has been done on 100-ft-
diameter tanks containing a light-end fuel. There is a large range in the size of ASTs,
which range in diameter from 10 to 200 ft and leak detection systems that work on the
smaller tanks will not work on the larger ones. Also, methods that work on the larger
tanks may constitute a case of "overkill" for the smaller tanks. Finally, some of the
techniques that will work with the light-end products may not work with the heavier ones.
The research program described in Figure 3-3 and being discussed with OERR addresses
these needs [C-34].
3.1.1.5 Preliminary Data Analysis (Loci Conceptual Model)
An understanding of the movement and disposition of released contaminants in the
subsurface environment is essential for selecting, designing and implementing an effective
remediation approach. Until recently, only minimal information was compiled and
generated to evaluate the behavior and degradation of motor fuel contaminants in the
subsurface environment.
In FY87, RREL initiated an intensive and comprehensive scientific literature research
effort to increase the level of understanding of the mechanisms affecting the fate and
transport of leaked motor fuels in the underground environment [C-19]. This effort
culminated in the development of a concept that a substance released from an UST will
be present in and transient between one or more locations in the subsurface environment
[B.26]. A total of 13 of these locations, referred to as physicochemical-phase loci, were
identified and defined (Figure 3-4). For example, contaminants may be dispersed as a
3-11
-------
Leak Detection
Wall Integrity
Tanks
Large Tanks
Small Tanks
Piping
(see UST Systems)
Secondary
Containment
Tank
Inspection
Corrosion
Prevention/
Monitoring
System Integrity
ASTs
Figure 3-3. RREL Aboveground Storage Tank Research Program.
3-12
-------
Water
fable
Locus
Number
Description
İ
Contaminant vapors as a component of soil gas in the unsaturated zone
İ
Liquid contaminants adhering to "water-dry" soil particles in the unsaturated zone
İ
Contaminants dissolved in the water film surrounding soil particles in the unsaturated zone.
İ
Contaminants sorbed to "water-wet" soil particles or rock surface (after migrating through the
water) in either the unsaturated or saturated zone
İ
Liquid contaminants in the pore spaces between soil particles in the saturated zone
İ
Liquid contaminants in the pore spaces between soil particles in the unsaturated zone
İ
Liquid contaminants floating on the groundwater table
İ
Contaminants dissolved in groundwater (i e , water in the saturated zone)
İ
Contaminants sorbed onto colloidal particles in water in either the unsaturated or saturated zone
İ
Contaminants that have diffused into mineral grains or rocks in either the unsaturated or
saturated zone
İ
Contaminants sorbed onto or into soil microbiota in either the unsaturated or saturated zone
İ
Contaminants dissolved in the mobile pore water of the unsaturated zone
Liquid contaminants in rock fractures in either the unsaturated or saturated zone
Figure 3-4 Description of Loci Conceptual Model
3-13
-------
component of soil gas (Locus #1), or nonaqueous phase liquid (NAPL) in the pore spaces
between soil particles in the saturated zone (Locus #5) or in the vadose zone (Loci #2
and #6). Collectively, these loci represent the possible phases and locations where leaked
substances may be present in the subsurface.
Based on this loci concept, RREL developed a methodology for analyzing the mobility
of petroleum contaminants in the subsurface and for screening applicable cleanup
alternatives. Worksheets were developed to determine where in the subsurface zones
most of the petroleum product is likely to be, and further, how likely the petroleum is to
move into and out of these locations. The results of this preliminary analysis will assist in
identifying and selecting an appropriate corrective action strategy based on a scientific
understanding of contaminant behavior and site conditions.
3.12 RREL Corrective Action: Past, Current and Future Research
RREL's overall research approach to the cleanup of petroleum-contaminated soil at
LUST sites combines the scientific principles governing the behavior of petroleum
products in the subsurface environment, i.e., the loci concept, with the specific
hydrocarbon constituents in different petroleum products, and the most feasible soil
treatment technologies.
The majority of petroleum products released from UST systems include motor fuels
(such as gasoline and diesel fuel), jet fuel (such as JP-4), heating oil, and lubricating oil.
These products are often referred to as single bulk fluids; however, each product consists
of a complex mixture of organic constituents. Gasolines, for example, typically consist of
C4-C12 constituents whereas diesel fuel consists of C12-C25 constituents. For aliphatic
compounds, low carbon number constituents have higher volatiles and higher water
solubility, while higher carbon number substances are less volatile and more immiscible.
Aromatic compounds such as benzene, toluene, ethylbenzene, and xylene (BTEX) are
more soluble in water than aliphatic compounds of the same carbon number. Figure 3-5
matches the representative range of hydrocarbon constituents in different petroleum
products with the most commonly considered soil treatment technologies.
Approaches to cleaning up petroleum-contaminated soil do not generally address the
entire mixture of compounds in a bulk blend, but are designed to address specific
constituents or classes of constituents. For example, soil vapor extraction may be effective
only for constituents containing 12 or less carbons (<0^). In addition, no single in-situ
technology is effective in addressing specific constituents in all loci; most may address only
a limited number of loci. For example, traditional pump and treat technologies only
address light nonaqueous phase liquids (LNAPL) on the groundwater table (Locus No. 7)
and some of the contaminants dissolved in groundwater (Locus No. 8); contaminants
present in other loci are not addressed. Consequently, corrective action technologies are
being misapplied in many cases or the effectiveness of single or multiple technologies are
not being optimized. Also, for certain in-situ technologies such as air sparging, or
integrated technologies such as soil vapor extraction/airsparging/bioventing,the funda-
3-14
-------
C
Vadose
Zone
Saturated
Zone
C8
JL
'10
^12 C
14
ikuJip^
'16
'18
'24 C
1 |T.C2ğ gao Cai
Gasoline
Diesel
Kerosene
Fuel Oi
Lubricating Oil
In Situ Technologies
Ex Situ Technologies
Soil Vapor
Extraction
Soil Vapor Extraction
and Bioventing
Thermal Desorption
Bioremediation
Soil Washing
Soil Vapor
Extraction and
Air Sparging
Soil Vapor Extraction.
Air Sparging, and
Bioventing
Figure 3-5. Range of Hydrocarbon Constituents in Different Petroleum Products
Associated with the Most Commonly Considered Cleanup Technologies.
(modified from Senn and Johnson, "Interpretation of Gas Chromatography Data as a
Tool in Subsurface Hydrocarbon Investigations," Proceedings of the NWWA/API
Conference on Petroleum Hydrocarbons and Organic Chemicals in Ground Water,
Houston, Texas, November 1985 )
3-15
-------
mental processes affecting performance limitations and effectiveness are poorly
understood.
Utilizing the loci concept, RREL is developing and evaluating a systems approach for
cleaning up petroleum-contaminated soil in both the vadose zone and the saturated zone.
Table 3-2 presents a matrix of corrective action technologies which have been, or are
currently being, studied in relation to various petroleum products and contaminant phases
and locations in the soil. The overall goals of RREL's program are to develop a
methodology or methodologies for selecting the most appropriate in-situ/ex-situ
technologies and to develop engineering criteria for the design, installation, operation and
performance evaluation of alternative approaches to "complete" site remediation. The
approach to date has been to concentrate on the most feasible and most commonly
considered in-situ and ex-situ technologies to optimize their application to LUST sites.
RREL's program will also concentrate on identifying, evaluating and optimizing new
approaches and technologies to expand current cleanup capabilities and to extend these
capabilities for treating significant contaminant masses in loci that are not currently being
addressed by traditional technologies, e.g., fractured rock media. The approach to carry
out these research activities is presented in Figure 3-6 and involves four main research
areas: Technology Screening, Technology Development and Evaluation, New and
Improved Technology Development, and Fractured Rock Media.
Table 3-3 summarizes RREL's research activities in Corrective Action from the start
of the program out to FY96; detailed project descriptions are presented in Volume II,
Appendix C. Also, the Corrective Action subtotals in Table 3-3 were used to develop the
total RREL funding history in Table 2-1. The following discussion addresses RREL's
research progression through the above mentioned four categories as further broken down
in Table 3-3. In addition, a discussion on RREL's program activities in Alternative Fuels
is presented.
3.1.2.1 Technology Screening
Until recently, UST investigators and regulators have relied on just one or two
corrective action technologies for the cleanup of petroleum-contaminated sites. The
approach used to select a technology is generally not founded on any sound technical
basis; most investigators use the technology that they are the most familiar with or that is
required by the state or local regulatory agency. One of the reasons for investigators
continuing to use this approach is that advancements in the development of new and
innovative corrective action technologies have only begun to be made in the last 2-3 years,
and transfer of information to the user communities on these technological developments
has not been completed. Furthermore, there is a basic lack of knowledge regarding what
site and release parameters should be evaluated to assist in the selection, design, and
implementation of appropriate corrective actions.
Site-specific information that can be used for the selection of a corrective action
strategy should be obtained as part of the site assessment process. Once the site
assessment has determined that a release occurred (which is generally accomplished in the
initial phase of the assessment), the focus of the process should be on providing informa-
3-16
-------
Table 3-2. Loci-Based Corrective Action Matrix (RREL)
Oo
Contaminant Phase
& Location in Soil
LNAPL
Removal
In Situ Technologies
Ex Situ Technoloj
ies
SVE
SVE/
Air Sparging/
Bioventing
SVE /
Bioventing
Bioremediation
Thermal
Desorptlon
Soil Washing
Liquid Phase
Vadose Zone
On "water-dry" soil
In soil pores
~ Ĥ
A
In rock fractures
~ Ĥ
A
A Ĥ
Saturated Zone
In pore spaces
A
On groundwater table
~ Ĥ
A Ĥ
In rock fractures
A
Vapor Phase
Vadose Zone
Soil vapor in pores
A
Dissolved Phase
Vadose Zone
Dissolved in soil-water film
A
Sorbed to "water-wet" soil
A
Sorbed on colloidal particles
A Ĥ
Diffused tn soil grain matnx
Sorbed to microbiota
A Ĥ
A Ĥ
A Ĥ
Dissolved in mobile pore water
A
A Ĥ
Saturated Zone
* Sorbed to "water-wet" soil
A
Dissolved in groundwater
A Ĥ
Sorbed on colloidal particles
A
Diffused In mineral grains
Sorbed on mlcroMota
A Ĥ
Key A = Gasoline; H = Diesel Fuel and No. 2 Heating Oil; # = No 5 and No. 6 Heating Oil
-------
Corrective
Action
Fractured
Rock Media
Program
Yes
Is Fractured
Rock Media
. Present7 .
Site
Characterization
No
Technology
Screening
New & Improved
Technology
Development
Technology
Development
and Evaluation
Integrated
Systems
In Situ
Technologies
Ex Situ
Technologies
LNAPL
Removal
Figure 3-6 Overview of RREL Corrective Action Research Program.
3-18
-------
TABLE 3-3. RREL PROJECTS IN CORRECTIVE ACTION
I.D.
PROJECT TITLE
RESOURCES (SK)
FY88
FY89
FY90
FY91
FY92
FY93
FY94
FY95
FY96
TECHNOLOGY SCREENING
C20
Evaluation of Sfte Requirements for Selecting Cleanup Technologies
150
150
150
TECHNOLOGY DEVELOPMENT/EVALUATION: PROOUCT REMOVAL
C21
Methodology for Assessing Spill Volume & Recovery of LNAPLs
50
50
100
100
TECHNOLOGY DEVELOPMENT/EVALUATION: In-situ TECHNOLOGIES
C22
Evaluation of SVE Technology at LUST Sites
150
250
250
250
C23
Optimization of SVE for Remediation of Gasoline-Contaminated Soil
50
80
120
100
100
100
C24
Evaluation of SVE with Air Sparging and Bioventing at LUST Sites
200
200
200
200
TECHNOLOGY DEVELOPMENT/EVALUATION: Ex-situ TECHNOLOGIES
C25
Evaluation of Soil Washing Technology for LUST Sites
350
160
50
50
100
C26
Assessment of Thermal Desorption to LUST Sites
80
120
100
100
100
C27
Evaluation of Ex-situ Bio-oxidation Technology for LUST Sites
100
150
200
200
200
C28
Potential Reuse of Petroleum Contaminated Soil
60
50
50
TECHNOLOGY DEVELOPMENT/EVALUATION: INTEGRATED SYSTEMS
C29
Development of an Integrated Systems Approach for Cleanup of LUST Sites
200
200
200
200
200
NEW AND IMPROVED TECHNOLOGIES
C30
Assessment of New & Improved Technologies for LUST Sites
50
50
100
100
150
250
FRACTURED BEDROCK
C31
Remediation Approaches for Petroleun Contamination in Fractured Bedrock
50
150
150
200
400
ALTERNATIVE FUELS
C32
Remediation Approaches for Soils Contaminated with Alternative Fuels
150
200
200
CORRECTIVE ACTION SUBTOTALS
150
600
540
590
870
1150
1500
1500
1500
3-19
-------
tion for the selection and implementation of appropriate corrective action technologies.
This requires an understanding of the subsurface environment, properties of petroleum
products, and mechanisms affecting the movement and disposition of hydrocarbons in the
subsurface. Though there have been a number of documents developed on various
aspects of UST corrective action technologies, only minimal information has been
generated addressing these fundamental issues. Currently, there is no guidance available
for remediation investigators to determine what corrective actions should be taken at UST
sites based upon the scientific principles governing the behavior of hydrocarbon
constituents in the subsurface environment.
Past Research. Based on the earlier "loci" work, RREL developed a new screening
methodology for selecting cleanup technologies for petroleum-contaminated soils at
leaking UST sites [C-19]. A description of the methodology is presented in several EPA
publications [B.26, B.27, B32]. The methodology enables the user to develop a
conceptual understanding of site conditions before extensive field studies, to define
remediation goals, to evaluate technologies capable of meeting remediation goals, and to
identify monitoring requirements during and after remediation. Working with site data,
the methodology provides an approach for a preliminary analysis of the location and
phases of contaminants present in the saturated and vadose zones, and for evaluating the
likelihood of contaminant migration within the soil matrix. Worksheets were developed to
evaluate how site-specific conditions pertain to the factors that favor or inhibit the success
of specific corrective action technologies.
Current and Future Research. Starting in FY93, RREL will initiate field validation
studies of the screening methodology developed, and a series of scientific research studies
(e.g., sorption kinetics of nonhomogeneous processes) to support the loci concept. The
results of these studies will be combined with an updated scientific literature search to
further enhance the science of phase mobility and to refine and confirm the loci concept
for better selection and application of corrective action technologies [C-20].
3.122 Technology Development and Evaluation
Technology Development and Evaluation involves understanding the fundamental
operating principles and processes of a specific cleanup technology, and then evaluating
criteria for that technology with respect to contaminant type, phase, and location. A set
of "rules" to assist in technology selection, design, and performance is then developed.
Understanding how the technology works and identifying critical design factors is
accomplished by the following research activities:
Preliminary reviews and assessments of technologies from published
literature and examination of site data.
Development of physical models based on bench-scale studies.
Performance of pilot studies to test control and design parameters.
Development of mathematical models to determine the influence of system
variables.
3-20
-------
The physical models provide basic information that can be used in designing pilot
studies. The mathematical models are used as tools in evaluating and understanding both
the physical models and the pilot studies. Pilot studies are conducted to develop design
criteria. Based on this research, design factors are developed and described in
engineering handbooks. Once the capabilities of a specific technology or set of
technologies have been assessed in the screening process and developed using physical
and mathematical models and pilot studies, they can be further evaluated during actual
remediations.
The core research activities of the RREL program are centered around understanding
the fundamental principles of specific technologies that clean up petroleum-contaminated
soil, with the ultimate goal of using combined treatment technologies that effectively
address all contaminant phases in the saturated and vadose zones. Within the last several
years, emphasis has been placed on the development and optimization of most likely
feasible technologies such as soil vapor extraction (SVE), air sparging and bioremediation
for the in-situ treatment of contaminated soil. Research activities are also investigating ex-
situ bioremediation and thermal desorption technologies for onsite corrective action. In
addition, research is addressing light nonaqueous phase liquid (LNAPL) contaminants that
accumulate on the water table surface, to determine what happens to these constituents in
the soil matrix when the water table fluctuates and how to improve and develop effective
removal techniques. RREL's past, current and future research program for LNAPL
Product Removal, In-situ Technologies, Ex-situ Technologies, and Integrated Systems is
discussed below.
D Low-Density Nonaqueous Phase Liquid (LNAPL) Removal
Following a release, petroleum hydrocarbons migrate vertically through the vadose
zone until encountering either the water table or a low permeability barrier. When the
hydrocarbon mass encounters such a barrier, the light nonaqueous liquid mass spreads
laterally, generally in the downgradient direction. This LNAPL product migrates under
the influence of groundwater flow as well as lateral and vertical dispersion of the product.
The most common product removal approach relies on the placement of extraction wells
to intercept the product plume and the pumping of what amounts to a varying mixture of
ground water and product to an oil/water separator on the surface for recovery or
disposal. Though this technique has been successfully applied at some leaking UST sites,
it is not without problems, e.g.:
Further contamination of ground water. During pumping, the groundwater table
and liquid product on the water table surface are drawn down, spreading liquid
product through the soils. When pumping is terminated (due to system problems,
maintenance, electrical outages), the groundwater table rises and allows
contaminants adsorbed to soils or residually trapped in soil to dissolve directly into
the ground water.
Ineffectiveness at sites with low-permeability soils. Decreased pumping rates can
significantly increase the time required for conducting remediation.
3-21
-------
Further contamination throughout the subsurface soils. Contaminants trapped
within soil interstitial spaces are extremely difficult, if not impossible, to remove by
pump and treat alone.
In addition, product removal techniques only address the mobile portion of the
LNAPL, the residual saturation portion (i.e., contaminants entrapped in the soil pore
spaces) must be either removed by in-situ volatilization or degraded by bioremediation
systems.
Past Research. Past research efforts conducted by the petroleum industry and
universities have been focused on the development of enhanced techniques for recovering
LNAPL on the water table, and primarily on increasing the recovery rate while minimizing
the amount of water recovered with LNAPL. Historically, research efforts have led the
recovery of LNAPL from skimmers to single pump systems, to dual-pump systems, to
vacuum enhanced pumping systems. Recently EPA-OUST, EPA-ORD (EMSL-LV, ERL-
Ada, OK), and universities have begun to focus on 1) minimizing the effects of "smearing"
or residual saturation of LNAPL during removal, 2) evaluating the influence of fluctuating
groundwater table on LNAPL removal, and 3) removing residually saturated hydrocarbons
and LNAPL in low-permeability soils.
Current and Future Research. RREL research is concentrating on developing and
testing methodologies for estimating hydrocarbon spill volumes and for optimizing the
design of systems for maximum product recovery [C-21]. The absence of these estimation
procedures complicates the selection of appropriate corrective action technologies and
makes it difficult to determine if the decline in product recovery represents effective
mitigation or an inappropriate technology selection. Research activities include: 1)
developing an interactive program and user's manual for LNAPL estimation and free
product removal system design; 2) comparing the analytical model, laboratory data, and
numerical simulations; 3) evaluating LNAPL removal techniques for fluctuating
groundwater tables; and 4) evaluating the model in the field. These activities will be
conducted under the project entitled "Development of a Systems Approach for Cleanup
Technologies" [C-29], and will include studies in large model aquifers to identify and
evaluate control mechanisms (e.g., pumping rates) that can maximize product removal
while minimize the volume of groundwater withdrawn and the amount of vertical
fluctuation induced in the static water level.
O In-situ Technologies
In-situ treatment involves the subsurface cleanup of contaminated materials. Within
the last two years, advances have been made in the development of new and innovative
in-situ cleanup technologies such as soil vapor extraction (SVE), air sparging, and
bioventing.
Soil Vapor Extraction/Bioventing. Soil vapor extraction systems are being used at an
increasing frequency for remediation of soils contaminated by volatile organic compounds
(VOCs). The interest in this technology is due in part to its demonstrated effectiveness
for removing volatile compounds, its relatively low cost, and the apparent "simplicity" of
3-22
-------
system design and operation. Although SVE may be "simple" in context, vapor behavior
in the soil environment is quite complex. In addition, details on system design and
operation have been mostly held by the process developers.
Past Research Recognition of these complexities led RREL to convene an
experts workshop in 1989 to discuss the state-of-the-art of SVE technologies and to
provide a forum to discuss site evaluation approaches, system design parameters,
operational experiences, attainment of cleanup criteria, post-closure monitoring, costs, and
research needs [C-22]. Using selected papers from this workshop, and other literature, an
SVE technology reference handbook was developed to provide a standard approach to the
design and operation of SVE systems [B.29]. Earlier work also included the evaluation of
air flow patterns and pollutants affected by SVE at a LUST site in Belleview, Florida and
resulted in the development of a field evaluation methodology for SVE [B.24]. In 1989,
OUST and RREL initiated a cooperative effort with a major oil company to conduct a
field demonstration project to assess the usefulness of a decision support computer model
to assess the application of SVE to LUST sites [C-22]. The program is currently being
reviewed by OUST for potential use as a training tool for SVE application. The project
also resulted in the development of a number of field test-and-evaluation methods
including an air permeability test and an SVE Quality Assurance Project Plan.
RREL also initiated a series of bench-scale column studies to evaluate SVE
performance and "cleanability" under varying operational parameters. The work was
intended to provide a technically sound means for evaluating SVE progress and for
identifying soil quality conditions at the completion of SVE operations. Residual
compounds were determined by utilizing both the Toxicity Characteristic Leaching
Procedure (TCLP) and an experimental aqueous solute teachability method. Published
results include characterization data on the types of hydrocarbons found in soils following
SVE operation [B31, B.69].
Current and Future Research A number of computer programs for developing
SVE system design information and for predicting operation efficiency have recently been
developed, additional models will probably be generated as more researchers focus on this
subject. RREL has documented the application of existing available programs [B35,
B.72] and plans to validate them so that SVE practitioners can rely on their use. This will
involve running the models with the same sets of actual field data; the predicted model
results will be evaluated against each other and compared to the observed data from the
field [C-29].
Large-scale tests are also being conducted in a model aquifer at the Oregon Graduate
Institute to identify the operational parameters that maximize SVE performance [C-23].
The presence of increased oxygen in the subsurface from the SVE process can also
stimulate aerobic microbial activity resulting in the biodegradation of hydrocarbons.
Future work will evaluate the performance of SVE when coupled with bioventing; both
processes can be operated with the same equipment, however each process has different
control parameters. Future large-scale testing will also investigate the performance of
SVE in combination with air sparging and aquifer heating.
3-23
-------
Other SVE related research will be accomplished in field studies of a systems
approach to the remediation of LUST sites, i.e., SVE combined with air sparging and
bioventing [C-24]. This work will be further discussed in the following section.
Air Sparging/SVE. Recently, an integrated approach to the cleanup of soils impacted
by petroleum hydrocarbons has been used to enhance soil vapor extraction and bioventing.
Typically, these systems are designed to address hydrocarbons in soil above the
groundwater table in the vadose zone. In many cases, however, residual-phase hy-
drocarbons are also present in soils below the water table in the saturated zone. These
hydrocarbons become trapped below the water table as a result of seasonal groundwater
table fluctuations, drawdown during pumping operations, and the presence of dense
nonaqueous-phase liquids (DNAPLS) that sink to the bottom of the saturated zone.
Soluble hydrocarbon constituent trapped below the groundwater table may serve as a
long-term source of dissolved contaminants that can impact groundwater quality.
Contaminants in the saturated zone "appear" to have been effectively removed using
SVE/bioventing systems in combination with air-sparging systems (which inject
pressurized air into soils below the water table) to strip and biodegrade residual and
dissolved phase hydrocarbons.
Air sparging is becoming a popular corrective action technique for enhanced
remediation of gasoline contaminated soils. Unfortunately, fundamental processes
affecting the design and performance of these systems has not been examined in detail.
Knowledge of these processes is important, however, because there is disagreement about
the physics of the process. The fact that the displacement of water (a viscous, wetting flu-
id) by air (a nonviscous, non-wetting fluid) is an unstable process indicates that
preferential air flow paths are more likely to occur than a uniform air displacement front.
The implication is that only a portion of the saturated zone soil may be remediated by this
process. In addition, phenomena observed in the field such as groundwater mounding in
sparging wells and increased concentrations of dissolved-phase constituents down gradient
of the sparging wells, have not been fully examined. Speculative explanations have been
provided for these phenomena, such as turbulence and remobilization of the residual
phase, but they are not supported or substantiated by scientific evidence.
The effectiveness of air sparging/SVE systems typically have been determined by
measuring air emissions from SVE wells and concentrations of dissolved contaminants in
ground water. The correlation between these measurements and subsurface changes,
however, has not been determined. The actual mass and concentration of residual-phase
hydrocarbons remaining in soils in the saturated and vadose zone after air sparging/SVE
has been completed, has not been determined.
This technique, however, does appear to be a potentially important tool for removing
contaminants in the capillary fringe as well as in the saturated zone, and for introducing
oxygen to enhance biodegradation in ground water. Although air sparging/SVE systems
have been reported to have been used with apparent success at a limited, yet increasing
number of sites, fundamental research needs to be conducted to determine the physical
processes of air injection and the practical considerations to improve the design and
operation of such systems.
3-24
-------
Current Research RREL's research into air sparging was a logical extension of
the work conducted on SVE. Work to date has involved the following tasks:
A review and assessment of air sparging technology from available literature and
from systems currently being used in the field [B-40]. The review provided
general information on the design and application of air sparging technologies
currently being used. A final report entitled, "A Technology Assessment of Soil
Vapor Extraction and Air Sparging" is being completed.
A series of experiments that empirically examined an air sparging/SVEsystem [C-
23]. Preliminary experiments have been conducted at the Oregon Graduate
Institute to observe the effectiveness of the aeration process. Additional
experiments are currently being conducted in large model aquifers to examine the
physical processes and design considerations, including optimizing extraction and
injection well locations, ratio and pressure, etc. and identifying performance limits
of SVE and SVE/air sparging with regard to post residual concentrations and
potential impact on ground water.
Field evaluation of air sparging/SVE systems [C-24]. Several air sparging/SVE
demonstrations have been initiated in cooperation with major oil companies, EPA
Regions, and states to conduct field evaluations of SVE/air sparging. These
projects are intended to provide data from actual sites to evaluate the use of this
technology in the field and to provide engineering documents for streamlining
SVE/air sparging design and operation.
Future Research As previously stated, there is a need to examine and assess the
fundamental physical processes which control in-situ air sparging. There is also a need for
a more comprehensive evaluation of the strengths and weaknesses of the technique and to
develop mathematical models which can be used to optimize the design and operation of
the process. To complement this research, laboratory experiments and field
demonstrations are required to develop engineering design criteria.
Future RREL research activities involves bench-scale experiments, pilot-tank testing,
and field demonstrations. The first, entitled "Development of an Integrated Systems
Approach for Cleaning Up LUST Sites" [C-29] includes, in part, developing and
optimizing an approach to the design of in-situ treatment systems, including LNAPL
removal, air sparging, SVE/bioventing and SVE/aquifer heating. The developed
approach will be evaluated in a two-dimensional physical model.
A series of experiments that empirically examine the SVE/airsparging process will be
conducted in a large three-dimensional model [C-23]. The physical modeling consists of a
simulated gasoline release in a mixed media and will involve direct visual observation and
computer modeling examination of the distribution of air in the saturated zone.
Monitoring techniques will be conducted in conjunction with EMSL to examine multi-
phase behavior during sparging. In conjunction with the sparging, SVE will be used to
evaluate the contaminant mass removed from the saturated zone.
3-25
-------
As part of the future research in air sparging, RREL will continue joint field
demonstration projects with EPA Regions, states, and major oil companies. RREL is
currently working with EPA Regions 11 and V on several sites, other Regions are
interested in similar projects. The goal of these projects is to obtain actual site data to
evaluate the approach and models developed and to evaluate the performance of the
technology in a range of site conditions. The results of this work will be an engineering
handbook for use by state regulators and consulting engineers to streamline the selection,
design and operation of this technology.
D Ex-situ Technologies
The recent focus of corrective action research is on onsite treatment strategies, and in
particular, in-situ technologies. These technologies cause less disruption of facility
operation, and do not present unnecessary health and safety risks resulting from removal
and transport of contaminated materials. However, there are situations where ex-situ
treatment of the soil is necessary (e.g., sites where immediate removal of contamination is
required because an imminent threat to a potable water supply exists) or where in-situ
remediation is not feasible (e.g., soil permeability in the vadose zone is too low).
Accordingly, RREL's research program is addressing the capabilities of the most
promising ex-situ technologies that can effectively be used to remediate LUST sites.
Hiermal Desorption. Thermal desorption is an applicable technology for the
remediation of soils contaminated by petroleum hydrocarbons. The technology uses direct
or indirect heating to vaporize and remove volatile and semi-volatile organic compounds
from excavated soils; decontaminated soils are often returned to the excavation site. The
technology has been demonstrated to be capable of meeting soil cleanup criteria for a
variety of types of petroleum products. However, the relationships between organic
contaminant removal efficiency, waste characteristics, process operating conditions, site
characteristics, environmental factors, regulatory requirements, and treatment costs are not
well documented; guidance on evaluating the potential use of thermal desorption for
petroleum-contaminated soil applications is needed.
Current Research RREL initiated a project in FY90 to assess the application of
thermal desorption to LUST sites [C-26]. The final report which is being completed will
provide UST Program Managers with an understanding of the capabilities, limitations, and
costs associated with the technology and guidance on applying the technology for the
treatment of soils contaminated with petroleum hydrocarbons [B33, B35, B.41].
Future Research The goals of RREL's future research activities in thermal
desorption are 1) to ensure that reliable information is available to allow thermal
desorption to be used to its fullest capability as a treatment technology, 2) to compile data
and assessments necessary to allow consistent application of regulatory requirements, 3) to
address treatment side streams, 4) to further demonstrate the application for treatment of
non-petroleum contaminated soils, and 5) to disseminate information regarding thermal
desorption to UST Program Managers, and regulatory personnel [C-26].
3-26
-------
During preparation of the guidance document on thermal desorption, a significant
data gap was identified regarding the application of this technology to the treatment of
non-petroleum contaminated soils. Although this type of contamination occurs at fewer
UST sites, it may be more problematic and is a less developed application of this
technology. Additionally, it is anticipated that contamination associated with leaking ASTs
will involve non-petroleum products. Future work will address the preparation of a
guidance document for application of thermal desorption to non-petroleum contaminated
soils [C-26].
RREL is also working on several joint field demonstrations with EPA Regions to
evaluate the application and performance of thermal desorption technology under a range
of actual LUST site conditions. The results of this work will be a guidance document and
workshop to assist the user community in determining the feasibility of applying thermal
desorption to a site and in designing and evaluating the performance of systems.
Bio-oxidation (Soil Mound). Treatment of fuel-derived hydrocarbons in soil via bio-
oxidation in soil mounds has recently been found to have much promise. Soil pile or soil
mound bio-oxidation systems are similar in construction and operation to aerated static
pile composting systems. Since the technology has only recently been applied to
contaminated soils, a variety of names are used to describe these systems including ex-situ
bio-oxidation, aboveground bioventing, soil heap venting, augmented vacuum heap,
aboveground bioaugmented soil venting, soil composting (a misnomer), bio-burritos, soil
mounds, and bio-piles.
Soil mounds are designed so that the factors governing aerobic biodegradation are
maintained in the optimal range and therefore conditions for efficient bacterial
degradation of hydrocarbon contaminants in soil are ideal. Soil mound ventilation is
perhaps the most critical component of the system operation. The addition of air must be
adequate to ensure a sufficient level of oxygen for microbial growth; excessive ventilation
may lead to drying of the mounds or cooling below optimal levels. Soil mound ventilation
system design parameters to date have been determined by relying on previous experience
and trial and error. Most ventilation system designs are considered proprietary, thus the
relative success of one design versus another is not clearly evident.
Current and Future Research During 1991 RREL initiated a project to evaluate
ex-situ bio-oxidation technology for cleaning up contaminated soil at LUST sites [C-27].
The initial phase of the study involved surveying the literature and assessing the state-of-
the-art of processes currently in use. A draft report entitled "Soil Mound Bioremediation
Technology Assessment" was completed in the fall of 1991 [B.43].
The critical design parameters associated with ex-situ soil mound technology are not
well understood. Guidance is required on such items as: appropriate soil mound
dimensions and spacing of vent piping; rate and method of introduction of air moisture,
and nutrients; amendments needed in the case of clayey soils; optimal temperature;
relationship between soil permeability and bulking agent; and relative removal rates as a
function of bio-oxidation vs. hydrocarbon removal due to soil venting. In an effort to
provide this guidance and promote the use of the processes to UST site remediation,
3-27
-------
RREL is working with several EPA Regions on demonstrating and evaluating the ex-situ
bio-oxidation technology at actual LUST sites. RREL will assist in preparing a QAPP,
conducting sampling and analytical tasks, and in analyzing and documenting the results.
Technical information will be provided on:
evaluating the applicability of the technique for a variety of petroleum products at
leaking UST sites.
designing and constructing bio-piles; operating parameters such as optimal
temperature, air flow, nutrients, etc.; and installation, operation and maintenance
costs.
testing to validate "cleanness" of treated soils and determine when soils can be
returned to the site, sent to a Subtitle C landfill, or treated further (e.g.,
stabilization if metals are present).
Soil Washing. Soil washing is a physical process in which excavated soils undergo
intimate contact with washing and rinsing solutions to promote reductions in contaminant
concentration and volume through physical separation. Contaminants which are loosely
attracted to larger sand particles are physically transferred to the wash solution.
Washwater treatment involves the removal of the contaminant and management of the
fine particulate residuals that are carried over in the washwater.
Past Research Past RREL efforts focused on bench-scale testing of synthetic soil
formulations contaminated with gasoline, diesel fuel and waste oil [C-25]. Testing was also
conducted on several actual LUST soils exhibiting different natural soil conditions.
Results from the synthetic soil indicated large reductions in contaminant concentration.
Results from the actual soils were less successful, which is indicative of the complexity
associated with treating "weathered" LUST sites [B.25, B.28].
Future Research RREL's Superfund research program is expending large
resources on soil washing technology, from bench-scale studies through pilot-scale and into
full-scale evaluations. Because of limited resources and other corrective action priorities,
the RREL will attempt to satisfy its UST needs in soil washing through the Superfund
program and will periodically review and assess the status of this research for application
to leaking UST sites [C-25].
Soil Reuse. Disposal of soil contaminated with petroleum products is costly and is
becoming more difficult as landfill resources become more limited. In the last several
years an increasing number of facilities, primarily asphalt batching and brickmaking
facilities, have been willing to accept hydrocarbon-contaminated soils. These techniques
are attractive alternatives for hydrocarbon soil remediations; however, an independent
evaluation of the applications and limitations of such methods is not available.
Current Research RREL initiated a project in FY1991 to identify and evaluate
facilities that are permitted to receive and process hydrocarbon-contaminated soil for
potential reuse [C-28]. A comprehensive Directory has been compiled that describes the
3-28
-------
treatment processes involved, their applications and limitations, and other salient technical
and regulatory information [B38]. The Directory also includes the identification of
facilities within geographical areas that could be used for remediation of specific sites.
Future Research Future RREL efforts will include the evaluation of the actual
processes identified in the earlier literature search and industry survey. Cooperative
bench-scale and pilot projects will be pursued with industries to evaluate processes and to
analyze actual recycled/reused soils. Additional soil reuse/recycling methods will be
evaluated. Possible additional applications include road bed base, landfill cover, concrete
and cinder blocks, backfill for abandonment of vaults, pits, ponds, or lagoons, etc. Results
of this work will be structured in the format of a guidance document or recommended
practice for using a specific type of remedial technology. Future activities will also include
periodic updates of the Directory.
D Integrated Systems (In-situ)
The goal of site remediation is to reduce contaminant concentrations to a
predetermined target without further spreading the contaminant constituents in the
environment. This should be achieved by using the most efficient and cost effective
technology or combination of technologies available. It is highly unlikely that the use of a
single corrective action technology will address the entire problem (for example, pump
and treat will not reduce residual contamination in soils, and, in fact, may increase the
volume of soil impacted by residual contamination). Under most situations, a combination
of technologies will be required.. This "systems" approach will require an understanding of:
How individual technologies act on different contaminant phases present in the
various subsurface locations (Loci).
How the operation of each technology is influenced by subsurface conditions.
How each technology affects the performance of other technologies that may be
utilized at a site, either concurrently or successively.
How each technology modifies subsurface conditions and how this change in
subsurface conditions affects the overall performance of the integrated treatment
system.
What the upper treatment efficiency limits are of each individual technology and of
the integrated system as a whole.
Past Research. RREL's earlier loci work advanced the understanding of the state of
the science of subsurface contaminant behavior and established the foundation for the
development of an integrated systems approach to LUST site remediation [C-19, B32].
The loci work provided the conceptual framework for determining where multiphase
contaminants are distributed in the subsurface, and what factors affect the distribution of
contaminants in the subsurface environment at a given site. Based on this information, a
3-29
-------
systematic remediation approach can be defined that involves a single technology or
combination of technologies (i.e., a treatment train approach incorporating LNAPL
recovery, SVE, SVE/air sparging or SVE/bioventing/air sparging) for removing the
pollutants in major loci. Past RREL research efforts have also provided information on
specific in-situ technologies [C-23, C-261 for remediation of vapor and dissolved phase
constituents in the vadose zone (i.e., Loci nos. 1, 3, 12). However, pollutants in many of
the other loci have not been addressed and will require an integrated treatment system
approach for complete site remediation.
Current and Future Research. In FY 1992, RREL initiated a project to develop an
integrated strategy for the recovery of LNAPLs, and the remediation of hydrocarixm-
contaminated soil in both the saturated and vadose zones [C-29]. The project will
examine and improve upon existing computer models for individual corrective action
technologies (e.g., LNAPL recovery, SVE, air sparging, bioventing) by using the results of
physical models, pilot studies, and field evaluations. Case study data from numerous site
remediations will be used to validate software for identifying when a remedial technology
has reached its technical limit at a given site and to develop a series of "type curves" for
rapid visual reference on various site conditions and likely endpoints of proposed
remediations. The verified models will then be used to determine the appropriate
coordinated use of technologies during different phases of corrective actions. Individual
models will be combined to facilitate optimum remediation system design, and to interpret
and analyze pilot studies and field evaluations of integrated systems.
The results of these studies will be used to develop engineering manuals on: 1)
methods for quantifying mobile and residual NAPL and procedures for removing free
product, 2) the design and application of air sparging/SVE systems, and 3) the design,
application, and evaluation of bioventing systems.
3.1.2.3 New and Improved Technologies
The sheer magnitude of the LUST problem makes continuous improvement in
corrective action capabilities a high priority. In addition to the extremely large number of
sites that have to be remediated, there is also the fact that only a few corrective action
technologies can be considered fully developed and routinely considered - if not used - by
remediation contractors. Perhaps only soil removal, product recovery via wells, and
groundwater "pump and treat" operations can be considered routine. Other technologies
such as soil vapor extraction and air sparging are probably routine for only a few
contractors, are still much in need of process enhancements, and still need to be further
demonstrated to a wider audience before they can be considered as routine.
There are many other corrective action technologies with potential applicability to
LUST sites. It is expected that many of these technologies, if properly developed, applied,
and demonstrated, would provide valuable additions to the list of technologies that
cleanup contractors would consider as routinely available. It is further expected that the
addition of these technologies would allow for quicker and more cost-effective cleanups at
many LUST sites.
3-30
-------
As indicated in Figure 3-7, RREL has established a systematic approach to
investigating and transferring information on other technologies that may be applicable to
cleaning up LUST sites. It is not the Program's intention to "re-invent the wheel" or to
regenerate reports that have already been published. The key questions being addressed
are: Which technologies would provide the most benefit to LUST corrective actions?
And, thus: Which technologies should be the focus of further research, development and
demonstration by RREL? Answering these questions is far from an academic exercise or
any detached R&D program. As previously noted, the need for better corrective action
technologies is driven by the need to remediate, over the next decade or two, tens to
hundreds of thousands of LUST sites.
Past, Current and Future Research. In an effort to identify the applicability of new
technologies for treating contaminated soil at LUST sites, RREL initiated a project to
review technologies that have been proposed for use under RREL's Superfund Innovative
Technology Evaluation (SITE) program (including emerging and demonstrated
technologies) [C-30]. A preliminary screening of these technologies resulted in the
following recommendations for further investigation for application to treating petroleum-
contaminated soils at LUST sites: steam stripping, radio frequency heating, soil flushing,
ozone oxidation, and solvent extraction. Initially, RREL proposes to assess the state-of-
the-art of these technologies as they apply to treating hydrocarbon-contaminated soil, and
to develop those technologies that hold promise for application to LUST site remediation.
Then, an expert workshop will be held to develop design information and to identify
research needs for each of the following technologies:
Steam Stripping In-situ steam stripping has been used to recover highly to
moderately highly volatile hydrocarbon contaminants. Steam is introduced into the
contaminated vadose zone through injection wells. Heat from the steam raises the
temperature of the soil and enhances the volatilization of the contaminants. The
technique is most amenable to contaminants with boiling points less than 250 °C.
Limitations include: low soil permeability, which would restrict steam and contaminant
movement, and the potential for uncontrollable migration of steam from the injection
wells, which could move contaminants into uncontaminated zones.
Radio Frequency Heating Radio frequency (RF) heating involves the
introduction of electromagnetic energy via electrodes for rapid and uniform in-situ heating
of large volumes of soil to the point where volatile and semivolatile contaminants are
vaporized into the soil matrix. Vented electrodes are then used to recover the gases. The
concentrated extracted gas stream that is recovered can be incinerated or subjected to
other treatment methods. The technology is applicable for treating both volatile and
semivolatile organic contaminants; treatment levels are potentially high, depending on the
waste characteristics and the homogeneity of the contaminated soil.
3-31
-------
UJ
OJ
KJ
Assessment ol Applicability ol trmovaln/e
Technologvs fo Treat (.LIST Sues
\v
UpDate of Literature Regarding Promising
Tochnotogğs, Interview Vendors, PRPs,
Workers in Government, Academia, Industry
Demonstrations of Promsng
Technologies Which Are Ready ior
Field Demonstration
Develop Prioritized Leting of
Most Promising Emerging
Technobgms
Host Symposium on innovative
USt Technobges
Host Symposium on Innovative
U$t Technology*
HostS)
>ymgosmm on fnnc
UST Technobgms
on Innovative
Fund Bench, Pitt Development of
technobgiea Wtvch Are Promising
But Not Ready for Field
Figure 3-7. RREL Research in Developing New and Improved Technologies for Application to LUST Sites.
-------
Soil Flushing This technique involves installing capture wells around a site to
intercept contaminated ground water. The ground water is pumped to the surface and,
ultimately, back onto the site. Before being re-applied to the subsurface, the ground
water is typically treated (via such systems as carbon filtration, bioreactors, etc.) to remove
soluble hydrocarbon contamination. As the water percolates through the soil, additional
contamination is removed by solubilization. The "recontaminated" ground water is
captured, pumped to the surface, and treated and the cycle begins again. Before being
reapplied to the site, the water may be amended by adding surfactants, adjusting the pH,
or adding nutrients to enhance the growth of soil microorganisms. The primary limitations
of this approach are related to the characteristics of the site. Solubility and mobility of
the contaminants are also important parameters.
Ozone Oxidation ~ Among the contaminants that are slow to respond to SVE
removal are those with a strong affinity for soil and components that have relatively low
vapor pressures. Some reports in the literature suggest that ozone can be used in
conjunction with SVE to oxidize in-situ hydrocarbon residues. Certain VOCs (e.g., TCE)
and PAHs have been reported to be degraded by this technique. There is little
understanding of the complex reactions involving ozone and soils or of the reactions of
ozone and contaminants in a soil matrix.
Solvent Extraction Solvent extraction is an ex-situ treatment process that
involves introducing excavated contaminated materials into a mixing chamber, adding an
extraction medium (usually an organic solvent), mixing, and separating the soil/water from
the extraction solvent. Most units permit the solvent to be reclaimed for reuse. Soils may
contain residual solvents, and the toxicity level of the solvent residues must be addressed.
Soil characteristics are a limiting factor; soils with high moisture or high clay content pose
serious materials handling problems.
3.1.2.4 Fractured Rock Media
The presence of fractured rock at a leaking UST site generally presents significant
problems in locating and remediating contamination. Rocks with fracture zones are
typically very permeable; leaked product entering a fracture network will travel through
the largest apertures very quickly, contaminating large areas in a short time. The first step
in removing liquid contaminant is usually local pumping. In this manner, free product may
be removed; however, because of the large volume of disconnected NAPL "blobs" and
filaments trapped against the smaller apertures, and the low porosity and high
permeability of the fractured network, relatively little free product is typically recovered.
Groundwater pump-and-treat is another method that is often used with very limited
success. In general there is a need to develop more effective methodologies for
understanding bedrock formations and contamination contained therein, and for
evaluating and developing technologies to effectively remediate this contamination.
Past Research. RREL's efforts to date in this program area have been to identify
fractured bedrock as one of the 13 loci (i.e., Locus #13 [B32]) where liquids can exist in
the subsurface, and to define the most important "rules" governing the transport,
partitioning, retention, and transformation of leaked motor fuels in this locus. In addition,
3-33
-------
RREL has developed a method using hydraulic fracturing and horizontal drilling to unlock
individual apertures, thereby creating a highly permeable pathway for delivery/recovery in
the fractured region. Unto itself, hydraulic fracturing provides little remedial effect, but it
offers the potential of dramatically improving the effectiveness of a variety of in-situ
remediation techniques such as vapor extraction, bioremediation, steam stripping, soil
flushing, etc.
Current and Future Research [C-31]. Under RREL's SITE Program hydraulic
fracturing is being demonstrated at two sites for the purpose of enhancing in-situ
remediation in ground contaminated with hydrocarbons and underlain by glacial till. One
site is utilizing SVE while the second is employing subsurface bioremediation. Initial
results indicate that both sites have benefitted from fracturing; recovery well radius of
influence and well yields at the SVE site are significantly higher in the fractured area, as is
the infiltration rate of peroxide and nutrients at the bioremediation site. RREL is
currently working with EPA Region IX to develop and evaluate an approach for
mitigating petroleum-hydrocarbon contamination in fractured bedrock at an actual LUST
site. Hydraulic fracturing and horizontal drilling will be considered as part of the overall
remediation approach.
Future research will also include some basic studies to better understand the behavior
and mechanics of multi-phase flow through fractures: In particular research will address:
1. field and laboratory experiments with actual fracture networks to develop a
comprehensive data base for fracture porosities, permeabilities, aperture sizes, and
other basic data;
2. the formulation of appropriate flow models to use to represent flow through
fractures;
3. the influence of wettability patterns, interfacial tensions, capillary pressure,
gravitational and viscous forces on flow through fracture networks;
4. the interactions between fractures and the rock matrix in both the saturated and
unsaturated zones; and,
5. data and a better understanding of fractures, including methods to determine
connectivity of fractures.
3.1.2.5 Alternative Fuels
As a result of several past oil embargoes and in particular the deterioration of the
nation's air quality, the United States has recently emphasized the development of
"cleaner" alternative fuels to potentially replace traditional petroleum fuels. The fuels
under consideration include methanol, ethanol and reformulated gasoline (conventional
gasoline with the addition of ethers such as methyl - or ethyl - tertiary - butyl ether).
Should a national program on the use of alternative fuels be implemented, these fuels
would be stored in existing UST systems and would be subject to the same Federal
3-34
-------
requirements as USTs containing traditional fuels. There is a real potential of leaks from
USTs containing these newer fuels; soils contaminated with these products will present
much different problems than soils contaminated with conventional fuels. Most of the
alternative fuels under consideration contain oxygenated organic compounds. Their
properties are different from those of petroleum hydrocarbons as are the mechanisms of
their transport and transformation in the subsurface environment. Consequently, the
treatment of soils contaminated by these products must be evaluated in terms of these
differences.
Past, Current and Future Research. RREL has recently been involved in a
coordinated effort (directed by EPA's Environmental Criteria and Assessment Office,
Research Triangle Park, North Carolina) to develop EPA ORD's "Alternative Fuels
Research Strategy." This strategy is predominantly an "Air" driven program addressing
global warming and the environmental impacts on health and ecosystems resulting from
the use of alternative fuels versus the use of conventional fuels. RREL's involvement is
from an engineering perspective of preventing, detecting, and cleaning up leaks from
USTs containing alternative fuels. Initial research would assess these areas based on the
work conducted on conventional fuels to identify any significant problems or differences.
In particular, corrective action technologies such as soil washing, thermal desorption, soil
vapor extraction, bioventing and air sparging will be assessed for their application to soils
contaminated with alternative fuels. Newly developed technologies such as solvent
extraction and ozonation may be more effective for these situations, accordingly, they will
also be assessed and evaluated [C-32].
32 EMSL-LV RESEARCH PROGRAM: SITE ASSESSMENT/CORRECTIVE
ACTION
As of early 1992, there were about 130,000 UST sites with confirmed releases, and
about 100,000 UST release sites have been investigated nationwide. Experience gained
from hazardous waste and Superfund sites has demonstrated the value of site
characterization. Inadequate characterization of sites has contributed to protracted
cleanup efforts; many such sites have had numerous, sequential investigations and
associated changes in remediation plans as new information about the sites was
uncovered.
Conventional methods for conducting site assessments, however, can delay cleanup
decisions for many months because they often require laboratory analysis or because the
data collected do not include information required to determine the feasibility of
remediation or to determine its design. In addition, site assessments can be costly,
reducing the federal and state funds available for site cleanup. State regulatory staff and
the consulting community need to be able to make cost effective, real-time, on-site
determinations of site conditions if they are to take action at UST release sites rather than
simply juggle their growing case loads.
Similarly, as of early 1992, approximately 80,000 UST sites were either being actively
remediated or were awaiting approval and implementation of corrective action measures.
Unfortunately, it frequently takes as long as a year to implement corrective action after
3-35
-------
the site has been assessed. The reasons for these delays include sequential submissions
and approvals of investigation and cleanup plans; limited understanding of the processes
that control remediation effectiveness; spending too much time fine-tuning system
performance prior to conducting full-scale cleanup; and poor or erroneous interpretation
of data collected while monitoring system performance and cleanup progress. Cleanup
delays, in turn, often allow significant amounts of contaminants to migrate farther, adding
to the time and cost needed to complete the cleanup.
In addition, two major clean-up approaches have predominated for several years. At
many sites, the remediation technique most likely to be approved as "complete" by state
UST staff has essentially consisted of extensive soil excavation and subsequent disposal in
landfills. With the potential for petroleum contaminated soil to be regulated as hazardous
waste under RCRA's Toxicity Characteristic Leaching Procedure rule [40 CFR 26124]
and increasing competition for scarce landfill space, this "muck and truck" option is
becoming more severely limited. At sites where groundwater has been contaminated, the
predominant remediation technique has been to pump out the contaminated groundwater
and treat it above ground. This is a slow and expensive process, and few such sites have
achieved closure.
Figure 3-8 presents an overview of EMSL-LVs strategy for conducting UST site
assessment and corrective action research. The figure shows EMSL-LVs major areas of
UST expertise: measurements to define site conditions, and monitoring and interpretation
to verify programs in remediation. Also shown in the figure are EMSL's six focused
research areas. Projects and programs within each area of research are described in the
following section.
Figure 3-9 illustrates EMSL-LVs approach to carrying out UST research. As shown
in the figure, EMSL-LV uses a combination of methods to isolate key questions for
investigation. Because EMSL-LV sponsors a variety of research activities at all scales of
inquiry-laboratory scale, large physical model scale, and field scale-results and findings
from one area can be tested, corroborated, and refined by complementary analyses.
Where necessary to generalize from specific experimental results to other applications,
EMSL-LV also sponsors some modeling activities.
Figures 3-10 and 3-11 show the results of this targeted research strategy. Figure 3-10
briefly describes and following sections elaborate more fully-how EMSL-LV research
products can be used to answer questions commonly asked during an UST site
investigation. For example, how bad is the release? What can we do about it? How well
are we making progress in cleaning up the subsurface?
Finally, Figure 3-11 summarizes the primary considerations used by EMSL-LV to
guide selection of projects and to provide a self-evaluation of our performance. These
considerations are: the length of time required to carry a project from concept to
prototype device or method; the applicability of the product or method to UST sites; and
the cost to EPA-ORD of carrying out the project. The figure summarizes these criteria
3-36
-------
RESEARCH FOCUSES #1-3:
METHODS FOR SAMPLING PETROLEUM COMPOUNDS.
INTERPRETING DATA TO DETERMINE EXTENT AND
LOCATION OF SUBSURFACE CONTAMINATION.
INTERPRETING DATA TO CHARACTERIZE SITE HYDROGEOLOGY.
PASSIVE
REMEDIATION
ACCEPTABLE
AGGRESSIVE
REMEDIATION
REQUIRED
f ASSESS \
SITE
CONDITIONS
MEASUREME.
-------
Lab Scale
Study of
Process
Numerical
Modeling to
Generalize
Results
Refine Key
Processes
Test at Field
Scale
TRANSFER RESULTS TO USERS
~ Distribute research updates via tank issues
~ Incorporate in ASTM guidelines and standards
~ Commercialize new sampling devices
~ Publish in peer review journals
Figure 3-9. EMSL-LV Research and Product Development Cycle.
3-38
-------
OJ
OJ
vO
HOW ĞAD IS THE RELEASE?
REAL-TOMB MEASUREMENT
OF PRODUCT DEPTH AND
LOCATION
RBAL-TMB ESTIMATES
OF SUBSURFACE EXTENT
OP CONTAMINATED
SOIL AND DISSOLVED
PLUMB
FIELD MEASUREMENT
OF SOL AND GROUND
WATER CONTAMINATION
ASSESS SOURCES OF
RELEASE AND PLUMB
CONFIGURATION
iECBION
POINT J
ICBWN
POINT >
All
PERMEABILITY
fROTOCOl
IMMUNO
IN SITU
TIME RELEASE
NUTRIENT
CORES
BAILEI
TEST
PROTOCOL
DECISION
SUPPORT FOR
NATURAL
BIOREMEDIATION
WHAT CAN WE DO
TO REMEDIATE?
SITING PRODUCT
RECOVERY WELLS
ASSESS FEASIBILITY
OF PRODUCT RECOVERY
POTENTIAL
ASSESS FEASIBILITY
OF VENTINC /SPA RCINC
ESTIMATE
BIODCCRADATION
RATES US INC FIELD
MEASUREMENTS
TREAT CONTAMINATED
GROUND WATER IN-SITU
WITH LOW MAINTENANCE
HOW WELL ARE WH DOING
WITH THE CLEANUTT
MONITOR PRODUCT REMAINING
THROUGH DIRECT
OBSERVATION
TRACK PRODUCT RECOVERY
FLOWPATT6, CORRECT
STAGNATION POINTS
MONITOR EFFECTIVE
RADIUS OF IN-SITU
AIR SPA RCINC SYSTEMS
SINGLE INSTUMENT.
REALTIME MEASUREMENTS
OF KEY IN SITU
ĤIOOECRADATION
PROCESSES
DBTBRMINB WHETHER
HYDROCARBONS ARE
BIOOeCRADINC
SUFFICIENTLY TO KEEP
PLUME STABLE
DECISION
SUPPORT PCM
NATURAL
BIOREMEDIATION
AQUIFER
DIPSTICK
FREE
PRODUCT
TRACERS
COj /Oj /HC
SENSORS
Figure 3-10. Application of EMSL-LV Products to Achieve Faster, Higher Quality UST
Cleanups.
-------
PROOUCT
OR METHOD
TIME TO DEVELOP
APPLICABILITY
TOSTTES
COSTTO
EFA-ORD
CONCEPT
PKOJHCTH)
FIELD USE
ELAPSED
TIME
POC5KX
REX
10/tt
5/91
Kmc*
ALL
SBOK
LAS-IN-A-BAC
10/87
5/91
44 am.
ALL
SSSK
DIPSTICK
3/8B
sm
Hint*.
35*
S5SK
SCXL VAPOK
SURVEY PROTOCOL
9/m
12/W
a*.
75*
MSK
SLUG TEST
PROTOCOL
5/90
9/92
29 me*.
60%
S30K
HYDROPHOBIC
WELL PACKS
6/90
4/92
23 WW.
50%
960K
TRACERS FOR MONITORING
PRODUCT RECOVERY
6/90
ongoing,
currently
in lab study
36mos.
(projected)
50%
$40K
BAILER TEST FOR
RECOVERY
6/90
ongoing
30 woe.
(projected)
50%
S30K
FIGARO AND
MOS STUDY
7/90
3/91
9 mas.
40%
S27K
DECISION SUPPORT FOR
NATURAL BIOttMEDLATION
10/91
9/93
24 mas.
(projected)
25%
S227K
GEOPHYSICAL MONITORINC
OF SPARGING
1/92
6/93
18 arm.
35%
S215K
IMMUNOASSAYS
FOR NAPTHALENE
2/92
9/93
20 mot.
(projected)
ALL
S125K
(projected)
COj /C^ SENSORS
3/92
11/92
9mo&
ALL
S190K
COj /Oi /HC SENSOR
3/92
3/93
13 moo.
ALL
S75K
Figure 3-11. EMSL-LV Products Track Record.
3-40
-------
for a number of projects conducted by EMSL-LV between 1986-1992. Products which
have wide applicability or which nil a specialized niche, and which can be carried out
quickly and inexpensively are regarded as especially successful research achievements.
3.2.1 EMSL-LV Site Assessment: Past and Current Research
Research sponsored by EMSL-LV on site assessment and characterization techniques
emphasizes the development of new monitoring methods designed to resolve questions
that currently impede accurate and rapid assessment of hydrocarbon contamination at
UST sites. At present, EMSL-LV has four cooperative agreements with universities
having project elements relating to UST site assessment and characterization Appendix C
includes a summary of all current EMSL-LV research projects).
Because many of EMSL-LVs cooperative agreements have multiple objectives,
highlights of past research findings are summarized below as they relate to EMSL-LVs
mission and OUSTs research interests. These findings are presented in the following:
1) Methods for sampling petroleum compounds.
2) Interpreting monitoring data to estimate the extent and location of subsurface
contamination.
3) Interpreting data to characterize site hydrogeology.
These are followed by a summary of the implications of these findings for planned
future research efforts.
3.2.1.1 Methods for Sampling for Petroleum Contaminants
The federal UST rules describe requirements for responding to confirmed releases
from USTs. As a matter of policy, OUST chose to keep the requirements of this section
quite general in order to accommodate new advances in measurement techniques and
advances in our understanding of hydrocarbon transport. OUSTs preference was to
provide a series of detailed guidelines on site investigation methods as these techniques
evolved, rather than to codify existing practice and stifle innovation. Thus, the rules
require only that tank owners and operators make arrangements to measure for the
presence of a release where contamination is most likely to be present at the UST site. In
selecting sample types, sample locations, and measurement methods, the tank owners are
required to consider the nature of the stored substance, the type of backfill, depth to
ground water, and other factors as appropriate for identifying the presence and source of
a release. In addition, the tank owners are responsible for determining the possible
presence of free product [40 CFR 280.62].
At the time the rules were promulgated, the major site investigation techniques used
at UST sites were quite limited. For example, free product investigations generally
consisted of simple bailing from existing monitoring wells to check for free product Soil
gas surveying techniques were becoming commercially available, however, there was little
consensus regarding the sources of variability in soil vapor readings, and very limited
3-41
-------
understanding of the physical and chemical properties that would affect vapor transport.
Similarly, techniques for measuring hydrocarbon concentrations generally fell at either one
of two extremes: literally having UST staff or contractors "sniff" for the presence of
hydrocarbons in soil or ground water, or conducting full-blown standard laboratory
analyses to analyze for TPH or BTEX in soil or ground water samples.
Research sponsored by EMSL-LV research sought to advance these site investigation
techniques, while recognizing the importance of keeping the techniques simple enough to
be used in the field by relatively unskilled field technicians. The major findings of past
and current research in site investigation include the following:
D Currently allowable sample holding times prior to standard laboratory analysis of
contaminated groundwater samples result in significant biodegradation of the aromatic
compounds, resulting in underestimates of the actual concentrations of aromatics in the
sample, and by extrapolation, at the UST site. Samples to be analyzed in the laboratory
must be preserved in order to prevent this biodegradation. Alternatively, a newly
developed field technique (see below), which eliminates the problem of sample holding
times, can be used to reduce the potential for systematic underestimates of the aromatic
concentrations in samples [C-36, C-38, B.180].
D Controlled field and laboratory comparisons indicate that headspace analysis of
ground water and soils can be an effective, rapid and reliable field screening approach for
gasoline contamination. The manual static headspace method has been shown to be a
fast, reliable field method to analyze not only for the aromatics (BTEX), but also for such
chlorohydrocarbon solvents as trichloroethylene (TCE) in groundwater and soil samples.
Using a portable gas chromatograph, equipped with a photoionization detector (PID), a
sampling protocol was developed that achieved method detection limits in the range from
lppb to lOppb, with a working linear detection range of about four orders of magnitude
[C-38, B.181, B.182].
0 A new method using the manual static headspace method was developed to enable in-
field determination of Heniys law constants for volatile compounds in ground water
samples. Three 40 mL VOA vials are filled with aliquots of the same aqueous standard
or unknown groundwater sample. Different amounts of the solution are withdrawn to
produce headspace-to-solution ratios between 03 to 7.0. Plots of 1 /peak area for each
compound versus headspace-to-solution ratio were found to give straight lines with high
linear correlations (0.99). Henry's law constants are easily obtained from the ratio of the
line's slope divided by its Y-intercept. This new method gave Heniys law constants in
excellent agreement with more elaborate, laboratory-based methods, yet does not require
laboratory analyses. Moreover, the new method does not require the operator to know
the actual concentration of each compound and enables in-field determination of Heniys
law constants for compounds in actual samples of contaminated groundwater [C-38, B.183,
B.184, B.185].
D At present, state UST staff and remediation contractors generally only have access to
relatively unsophisticated monitoring equipment, such as total organic vapor (TOV)
detectors for their field monitoring. Conventional procedures for using TOV detectors
3-42
-------
produce only semi-quantitative results with high variability in the contaminant values. A
protocol was developed to improve the sensitivity and reproducibility of results obtained
when using TOV detectors through the use of Tedlar Bags for collecting samples, and by
performing serial dilutions of the sample. This procedure enables state UST staff to
obtain high-quality ground water contamination data in the Held, using instruments they
already have or can easily afford [C-38, B.186].
D A new method has been developed to determine the depth below ground and the
thickness of free product in sandy water-table aquifers. The new tool, known as the
Aquifer Dipstick, consists of a 3/4 inch diameter stainless steel rod with a 3-foot long
chemical indicator strip along the outside. This indicator strip changes color when in
contact with product. An electrode near the tip of the Dipstick detects the presence of
water-saturated soils, indicating the depth to which it should be hammered into the
ground. The Dipstick is left in the ground for about 20 minutes to allow the indicator
strip to change color, if it is in contact with free product. The Dipstick is then withdrawn,
enabling the field operator to measure the depth to free product and the thickness of the
free product along the capillary fringe as indicated by the color change.
In shallow aquifers, the Dipstick is simply pounded in the ground by hand. In deeper
aquifers, the Dipstick rod, which comes in 5-foot lengths that thread together, can be
mounted to drill rods and inserted through a hollow-stem auger bit down to the water
table.
This new tool can be used to expedite the search for free product over the use of
conventional soil borings or wells. Because the Dipstick's color indicator is reversible, the
same tool can be successively used at a site. This enables rapid assessment of the location
and depth of the free product plume, and reduces the need for more costly soil borings
and monitoring wells. Where additional borings or wells are required, preliminary
reconnaissance with the Dipstick enables field crews to improve the siting of soil borings
and wells.
Measuring free product locations and thicknesses with the Dipstick is not only less
expensive than with monitoring wells, but also more accurate since it measures the actual
thickness of free product in the ground and aquifer material. By contrast, the product
thickness in monitoring wells is 2.5 to 10 times greater than in the surrounding media.
The Dipstick has been field checked and cross-validated using results from monitoring
wells, test pits, bailer tests and soil samples. The tool's design and field durability are
being further refined through additional field testing. The original design has been
patented and will soon be commercially available [C-39, B.187, B.188].
32.12 Interpreting Monitoring Data to Estimate the Extent and Location of
Subsurface Contamination
Federal rules for UST site investigation also require tank owners to arrange for
determining the full extent and location of soils contaminated by UST releases; to
estimate the type, quantity and thickness of free product observed or measured in wells,
boreholes or excavations; and to determine whether the release has come into contact
3-43
-------
with ground water [40 CFR 280.64 and 280.65]. As with the requirements to sample for
hydrocarbon contamination, the rules do not specify the methods to be used.
At the time the rules were promulgated, the major methods for making these
investigations included the use of standard ground water monitoring wells as developed
under RCRA and other ground water protection programs, conventional free product
recovery wells, and an undue reliance on excavating very large pits to determine the full
extent of soil contamination.
The major findings of EMSL-LV sponsored research in this area include the following:
D Groundwater quality data collected from conventionally constructed monitoring wells
provide only qualitative information about the distribution of contamination in the
aquifers. Such data may underestimate contaminant concentrations in the formation by
orders of magnitude and may be misleading with respect to understanding processes and
conditions that affect contaminant transport. Observed contaminant concentrations
appear to be a function of screen position and depth, the amount of water removed
during purging, purging method, vertical distributions of contaminants, sand pack
properties, and vertical variation in hydraulic conductivity. Ongoing and future work is
focused on estimating the error to sampled contaminant concentration values contributed
by each of these factors and on improving methods to control these resources of variability
[C-38, B.189, B.190, B.191].
a Separate-phase hydrocarbons (or free product) do not readily enter in monitoring
wells due to the interplay of capillary and gravity forces. Moreover, once free product
enters and accumulates in the well, its thickness usually greatly exceeds the thicloiess in
the aquifer material. Estimates of subsurface volume of free product based on product
thicknesses measured in wells are notoriously poor. A field study determined that better
estimates can be obtained using the smaller product thickness values obtained from bailer
test analysis by Yaniga's method, or from the CONCAWE equation, or from the Aquifer
Dipstick [C-39, B.192].
D The movement of gasoline hydrocarbons was studied in a large three dimensional
model aquifer (dimensions 70 ft x 30 ft x 15 ft) designed to simulate an underground
storage tank backfill zone. A slow leak (0.2 gal/hr.or 0.8 L/hr) introduced hydrocarbons
into the unsaturated zone of the pea gravel aquifer approximately 0.5 m below ground
surface and 2.5 m above the water table. A total of 204 L (55 gal) of product was
released. Ground water was flowing beneath the release at about 1 meter/day.
Movement of the hydrocarbons in the free-product, vapor and aqueous phases was
simultaneously monitored using three-dimensional networks of vapor and ground water
samplers and a down-hole video camera. Three major findings emerged from this study:
1) vapor transport is the most rapid contaminant transport mechanism, supporting
the use of external vapor detectors as a leak detection method.
2) free phase petroleum product can accumulate in the porous medium outside a well
for long time periods before entering the monitoring well, complicating even the simple
3-44
-------
determination of whether separate phase product is present at an UST release site. This
is true even in pea gravel, where capillary forces which prevent movement of product into
the well are minimal.
3) fluctuation of the water table and subsequent smearing of the free product in the
saturated zone are key factors in determining the speed at which the gasoline constituents
solubilize into groundwater and the maximum contaminant concentrations achieved in
groundwater. In the absence of water table fluctuations, the dissolved contaminant plume
is on the order of tens of centimeters thick [B.193, B.194].
D Similarly, data collected at actual service station sites support the observations from
the large simulated aquifer facility. Vertical contaminant profiles obtained from improved
multilevel sampling at field UST sites suggest that concentrations of aromatics decrease
rapidly with depth below the water table and that the vertical dispersion of contaminants
is on the order of diffusion in saturated porous media [C-38, B.195, B.196].
D Results from multilevel soil gas sampling suggest that it is possible to distinguish
between vapors emanating from ground water contamination versus those from free
product based on the relative abundances of aromatic compounds found in the sampled
vapors. Ongoing work is investigating the feasibility of developing guidelines to interpret
such patterns in VOC vapor ratios in order to make these determinations. If such
guidelines are possible, this capability would accelerate the delineation of the contaminant
plume for each hydrocarbon phase present at UST leak sites, which would in turn help
describe the risk posed by those site conditions [C-38, B.197, B.198].
D Methyl-t-butyl ether (MTBE) is being increasingly used as a gasoline additive in
several regions of the U.S. due to its octane-enhancing ability and the ease with which it
can be commercially produced. EPA allows MTBE to be added to gasoline up to 11
percent by volume. As a potential ground water contaminant, however, MTBE has a high
water solubility and is not readily biodegraded. At a field research site, the site was
characterized by analyzing groundwater samples using the static headspace method taken
from far-field and bedrock monitoring wells and a lone peak due to MTBE was detected.
The ready detection of a lone peak in the field using a portable gas chromatograph
indicates that MTBE can be a reliable early indicator of far-field gasoline contamination
and its use as an indicator of far field contamination has been adopted by several state
UST programs in New England [C-38, B.199].
3.2.1.3 Interpreting Data to Characterize Site Hvdrogeologv
The federal rules require that owners of UST systems, with confirmed releases that
have reached ground water, to submit information on the hydrogeologic characteristics of
the UST site and surrounding area [40 CFR 280.65]. This information was intended to
help state UST staff determine the potential for exposure to hydrocarbons from the
release and to evaluate the possible need for a full corrective action plan for the site.
At the time the rules were promulgated - and even today - there are few
hydrogeologic investigation procedures tailored to the size and characteristics of most UST
3-45
-------
release sites. EMSL-LV has recently sponsored research to address this gap in
investigation procedures. The major finding to date include the following:
D Hydraulic conductivity values may be obtained from pumping tests, however, pump
tests are not usually performed in the early stages of an UST investigation. Instead, slug
testing has become the most widely used means to determine hydraulic conductivity values
at UST sites. To derive hydraulic conductivity values, the aquifer response data are
interpreted using slug test solutions applicable to different types of well geometries. The
popularity of slug testing stems from a desire to minimize ground water flow disturbance
and to avoid the handling, storage and disposal of large quantities of contaminated ground
water typically derived from a pumping test. Unfortunately, the slug tests are usually
performed at monitoring wells which are constructed such that the screen section is
surrounded by a sandy backfill zone and the screen extends above the water table.
Currently, there is no definitive method for determining hydraulic conductivity values from
slug tests for this well geometry. It is not clear that the hydraulic conductivity values
derived in this manner are meaningful for estimating transport properties or remediation
feasibility at UST sites. Ongoing studies are assessing the influence of backfill sand pack
on the resulting hydraulic conductivity values, with the goal of developing slug test
solutions specific to monitoring well geometries typically found at UST sites [C-38, B.200].
D Hydrocarbon accumulations measured with the Aquifer Dipstick or with monitoring
wells coupled with water table contour maps can show where product is located and the
direction it is likely to move. This information is closely related to site hydrogeology. An
even better idea of hydrocarbon transport directions can be obtained using tracers in the
hydrocarbons. Ongoing laboratory studies are testing two tracer compounds for suitability
for field trials [C-39, B.201].
D Spatial variations in absolute soil gas concentrations and in relative abundances of
vapor constituents in glacial till may vary by orders of magnitude over horizontal distances
of ten to twenty feet and over vertical distances of only a few feet [C-38, B.202].
322 EMSL-LV Site Assessment: Future Research
The major focus of EMSL-LVs past and ongoing work in site assessment has been to
establish a better understanding of gasoline transport in order to support development of
monitoring devices and guidelines for assessing releases. Advances in our understanding
of site contamination enabled by new monitoring procedures has provided us a
dramatically different picture of subsurface contamination for the comparatively simple
hydrogeologic regimes found at many UST sites. For example, we have now observed in
both controlled and field settings that, in the absence of extreme water table fluctuations -
- either naturally occurring or due to excessive dewatering during remediation - dissolved
ground water contamination is generally limited to a very thin vertical zone, and that
rebounding water tables cause dissolved contamination to reach saturated levels within a
matter of hours.
We also are developing a better understanding of where the greatest mass of
hydrocarbon is likely to be located in different settings. For example, in unconsolidated
3-46
-------
water table aquifers, the majority of the most difficult to remove gasoline hydrocarbon
mass will likely be just at or below the capillary fringe. For sites having a highly stratified
subsurface, we can also anticipate areas of greater hydrocarbon concentrations. For
example, transport and accumulation of hydrocarbon vapors can be anticipated just below
tight layers such as concrete, asphalt, hardpans, tight silts and caliches.
New work on site assessment techniques will focus on broadening our understanding
of hydrocarbon and other non-aqueous phase liquids (NAPLs) transport and measurement
in two primary ways. First, we will extend our research investigations to include
compounds beyond those in the gasoline hydrocarbon range (e.g., to include other fuel
types, different hydrocarbon classes, and to include preliminary work on other chemicals,
such as solvents, also stored in UST systems). Second, we will expand our investigations
to include methods to sample for these compounds in more challenging hydrogeologic
environments such as tight silts, glacial tills, and fractured bedrock.
Future site investigation and characterization research at EMSL-LV will include the
following projects.
3.2.2.1 Combined Carbon Dioxide. Oxygen and Hydrocarbon Field Sensor
EMSL-LV is exploring development of a prototype field portable vapor sensor that
would provide real-time, remote measurement of four vapor phase parameters: carbon
dioxide, oxygen, methane, and total hydrocarbons. These four parameters are critical to
assessing the presence of naturally occurring biodegradation and also for monitoring
enhanced bioremediation at UST sites. Currently, there is no single field portable sensors
capable of measuring these parameters. Moreover, the accuracy and stability of response
for existing sensors is poorly known. If possible, such a prototype device could greatly
accelerate assessment of biodegradation potential and processes at UST sites. In addition,
interpreting the significance of the measured vapors would be supported by other EMSL-
LV sponsored field studies of naturally occurring biodegradation (as described in the
Corrective Action Monitoring section that follows).
3222 Immunoassay Test Kits Tailored to UST Applications
EMSL-LV has developed monoclonal antibodies for use in an immunoassay test kit
for field analysis of benzene, toluene, ethyl-benzene, and xylene (BTEX). Immunoassay
techniques offer several advantages over other techniques for field use at UST sites. For
example, the natural selectivity of the antibody reduces the need for rigorous sample
cleanup in preparation for analysis, yet still allows semi-quantitation in the high ppb range.
In addition, the antibodies react similarly to similar groups of compounds, and thus
provide information on the presence of aromatic compounds beyond just the BTEX
compounds.
In cooperation with state UST programs and the American Petroleum Institute,
EMSL-LV will explore the development of additional immunoassays for UST site use.
Two target compounds -- total petroleum hydrocarbons (TPH) and napthalene - are
under consideration. TPH measurements are required by many state UST programs, yet
3-47
-------
current measurement methods are costly and require time-consuming laboratory
procedures. Napthalene measurements are not generally required by state UST programs,
but may prove to be very valuable in UST investigation and cleanup decisions.
Naphthalene appears to correlate reasonably well with laboratory estimates of oil/water
partitioning coefficients. Subsequent analyses will determine whether napthalene fits
EMSL-LVs criteria for a test-kit compound that would provide additional information on
the teachability of residual hydrocarbons in the soil.
3223 Improved Non-Invasive Site Investigation Techniques
Recognizing the limited resources available to conduct subsurface investigations,
EMSL-LV is exploring how non-invasive geophysical techniques can best be tailored to
UST site characterization needs. Geophysical methods such as ground-penetrating radar
(GPR) can be used to map the shallow subsurface, with typical penetration depths of 1 to
30 meters in shallow sediments.
EMSL-LV sponsored research at Ohio State University is investigating the effects of
seasonal fluctuations in soil moisture content on GPR instrument response. New project
work will determine if GPR can: 1) accurately map the location of the water table under
a variety of hydrogeologic conditions, and 2) detect accumulations of gasoline in the
vadose zone and on the water table.
3.2.2.4 Site Characterization Procedures for Fine-Grained Soils
There has been limited success with efforts to remediate fine-grained soils such as
clays and silts. This is due to primarily to the low permeability and strong capillary forces
which limit hydrocarbon mobility and mass transfer. EMSL-LV is investigating
collaborative research on the processes that control movement of hydrocarbons in fine-
grained soils and on methods for characterizing such sites in preparation for remediation.
The major transport processes to be investigated include air movement and the
distribution of free phase hydrocarbon in fine grained soils. With regard to air movement,
the principal issues are to determine: 1) how the diffusion of contaminants into fine-
grained soils limits the effectiveness of soil vapor extraction; 2) the constraints on oxygen
transport and its effect on biodegradation; and 3) the extent to which air advection can
improve biodegradation processes. With regard to the distribution of free phase
hydrocarbons, the primary issues are to determine: 1) the degree to which hydrocarbons
move through bulk soil as contrasted with movement through secondary pores and
fractures, and 2) how far hydrocarbons will spread in silt.
A variety of site characterization techniques will be used in the study. These include
the use of cone penetrometers for measuring soil stratigraphy and to detect the presence
of hydrocarbons within different stratigraphic layers; tracer tests to measure the advection
of air through a tight undisturbed soil in order to provide information on oxygen transport,
soil gas movement, and a direct measure of vapor velocity, the use of neutron probes and
time-domain reflectrometry to measure the water content of unsaturated soils having
different permeabilities.
3-48
-------
322S
Site Characterization Procedures for Fractured Bedrock
Ongoing EMSL-LV sponsored research at the University of Connecticut is
investigating the development of site characterization procedures to determine the
presence of fractures in bedrock (this work is co-sponsored by the USGS and the
Connecticut Department of Environmental Protection). This integrated study is
investigating the use of passive vapor samplers (Petrex samplers) to delineate the presence
of fracture systems. Samplers have been buried at different depths in the vadose zone
within a grid pattern chosen to intersect known fracture planes. Contaminants will be
desorbed from the samplers and the pattern of contaminant concentrations analyzed to
determine the degree of correlation with the fracture patterns. Future research will focus
on integrating a variety of investigation techniques with the objective of distinguishing the
location of water and non-water bearing fractures, and of contaminated versus non-
contaminated fractures. These techniques will include a variety of geophysical techniques,
including cross-borehole tomography, electrical resistivity, and seismic technique, as well as
the use of tracers.
323 EMSL-LVs Corrective Action: Past and Current Research
Research sponsored by EMSL-LV on corrective action emphasizes the development
of monitoring devices for obtaining data and development of guidelines for interpreting
data required to design in-situ, subsurface remediation systems and to monitor cleanup
progress in the subsurface. EMSL-LV currently has six cooperative agreements with
universities that have project elements relating to UST corrective action (see the
Appendix for a summary of these cooperative agreements).
As with the discussion of research activities on UST site assessment, highlights of past
and current research are first summarized in the following categories:
1) Monitoring and interpretation to support design of subsurface remediation systems.
2) Monitoring and interpretation to verify progress in subsurface cleanup.
323.1 Monitoring and Interpretation to Support Design of Subsurface
Remediation Systems
The federal rules for UST remediation support the use of in-situ remediation
techniques over wholesale soil excavation as a remediation option [FR vol. 53, No. 185,
V.F. 2]. The rules also require tank owners to arrange for free product removal in a
manner appropriate to site-specific conditions and which minimizes the spread of
contamination into previously uncontaminated zones, such as might be caused by excessive
ground water pumping to induce a cone of depression for product recovery [40 CFR
280.64]. Finally, the UST rules are unusual in that they allow UST owners, in the interest
of minimizing environmental contamination and promoting more effective cleanup, to
begin cleanup of soil and ground water before receiving final approval by a state UST
program of their remediation plan [40 CFR 280.66]. This provision was included in
anticipation of the enormous number of sites that were expected to require cleanup and
to encourage swift action at these sites. Exercising this option, however, requires the UST
3-49
-------
owner or operator to submit data on site hydrogeology and contaminant location, as well
as information to support their selection of remediation techniques and cleanup progress
monitoring.
Research on corrective action sponsored by EMSL-LV has thus focused on providing
information to enable state UST staff and UST remediation contractors to make one of
two decisions early in the remediation process: (1) either the site has a great deal of free
product present and has other site characteristics that pose a high risk of human exposure
and thus warrants immediate, aggressive remediation, or (2) contamination at the site is
relatively stable, and can be adequately managed through careful monitoring to
demonstrate continued site stability or through low-technology enhancements to naturally
occurring bioremediation.
Consequently, EMSL-LV research has focused on improving our capabilities to quickly
define the necessary and feasible remediation options for specific site characteristics, and
to improve our abilities to remove contaminants from the subsurface. Recent research
findings in this area include the following:
D The swift removal of free product at UST sites is a standard first response action at
sites where large amounts of free product threaten ground water. Very little attention,
however, has been given to the testing and design of filter packs for the purpose of
improving the rate of free product recovery. Methods used for designing filter packs for
product recovery wells have been adopted primarily from the water well industry, whereas,
hydrocarbon monitoring and hydrocarbon recovery wells typically contain both oil and
water. Laboratory studies have shown that standard recommendations for gravel pack
design - developed for water wells ~ may not produce the most efficient recovery of
product.
The laboratory studies investigated the:
a. effects of morphological characteristics (e.g., shape, size and mineral composition)
on product recovery efficiency.
b. effects of grain composition on product recovery performance.
c. ability to improve product recovery by chemically treating the packing material to
make it hydrophobic.
d. durability of water-repellent chemical treatment for pack sands.
e. chemical composition of leachate from treated gravel packs.
The studies showed that when oil is the nonwetting fluid relative to water (which is
usually the case at UST remediation sites), pore throat size controls the ability of oil to
move through porous media. Conventional water well design, however, recommends a
uniform rounded quartz sand for the gravel pack. Fourier image analysis was used to
quantify the shape and detailed grain sizes of four packing materials studied. The well
pack material producing the most effective hydrocarbon recovery had the least quartz, the
roughest and most angular grains and the least uniform grain size distribution.
3-50
-------
The study also compared product recovery rate for treated and non-treated sand
packs. Results showed that the gravel packs that were chemically treated to make them
hydrophobic outperformed untreated gravel packs in a series of laboratory bail-down tests,
indicating improved product recovery. Tests also showed that treated gravel packs
retained their improved performance for close to a year.
Leachate analyses conducted to determine the potential risk to ground water from the
treated sand packs showed the presence of BTEX compounds in the low ppb range.
These values, however, should be considered with respect to the fact that the product
recovery wells for which they are designed typically recover fluids containing
approximately 1% benzene, 10.5% toluene, 12.4% p-xylene, 5% trimethylbenzenes and
4% dimethylbenzene. Thus, the very slight addition of organics should be weighed against
the improved recovery of separate phase hydrocarbon from the subsurface.
Ongoing and future work is nonetheless investigating the use of inert, hydrophobic
gravel pack materials. Early tests indicate that unsieved PFTE (i.e. Teflon) chips have
even greater permeability to hydrocarbons and provide the greatest product recovery.
The degree of improvement appears to be proportional to the gravel packs'
hydrophobicity, although a few other variables also appear to be influential. A follow-up
field-scale study to compare the recovery rates for a PTFE-enhanced well pack and a
conventional sand pack began at a Michigan service station in April, 1992 [C-39, B.2Q3,
B.204].
D In 1976, Schwille presented a conceptual model of inorganic water quality attributes
associated with hydrocarbon releases to ground water. His model predicted the formation
of a reduction zone, a transitional zone, and an oxidation zone. Empirical data from
intensive field monitoring at two UST release sites corroborate his conceptual model and
suggest that in-situ natural biodegradation appears to be containing the plumes at each
site. The sites were sampled periodically for 15 and 18 months, respectively, in order to
analyze the temporal variations in inorganic water quality parameters. In addition, spatial
concentrations were analyzed along the centerline of the ground water plumes.
Field instruments were used to measure dissolved oxygen, dissolved carbon dioxide,
direct redox potential, pH, ammonia, nitrate and chloride, as well as for BTEX
measurements. The measurement of these parameters were typically completed within
fifteen minutes after collection of the ground water sample. Use of the field instruments
avoided the delays required for conventional laboratory analyses and reduced the usual
uncertainties in the measured values due to sample decomposition, such as losses in
carbon dioxide, oxygen, nitrate, ammonium, volatiles. Ion selective and gas permeable
electrodes were used to for the inorganic analyses, and a static headspace analysis was
used for the BTEX measurements [C-38, B.205, B.206, B.207].
D A field study at two UST sites in Utah has begun for the purpose of developing a
decision support tool for routine use in assessing whether naturally as a occuring
biodegradation processes are likely to be sufficient to stabilize the dissolved ground water
plume at specific UST sites. The field sites are chosen to contrast biodegradation
processes within a fairly homogeneous sandy soil and within tight silt soil. The field
3-51
-------
studies will assess the natural biodegradation reactions occurring at the Held site; it will
assess and recommend field sampling and analytical methods with which to best quantify
the observed biodegradation reactions based on a comparison with rigorous laboratory
methods; and it will use the field generated biodegradation data as input for calibrating a
fate and transport model. The model can then be used to simulate the likely long-term
effectiveness of natural biodegradation for containing the plume on site and to estimate
how the naturally occurring rates might be improved through low-technology
enhancements, such as low air flow venting. As discussed in the next section, this decision
support tool is also designed to assist in the interpretation of monitoring data at sites
where naturally occurring bioremediation is allowed to proceed [C-41, B.208].
3232 Monitoring and Interpretation to Verify Progress in Remediation
All sections of the federal rules relating to corrective action include the requirement
that the UST owner submit information regarding the actions they have taken. In
particular, UST owners are required to monitor, evaluate and report the results of
implementing their corrective action plans according to the schedule and format required
by the state UST program [40 CFR 280.66].
At the time the rules were promulgated, few states had developed formats for this
reporting requirement. Several of the states that did have monitoring requirements
established often transferred these requirements directly from other waste programs.
Many of these monitoring requirements did not reflect the key variables influencing
remediation progress at UST sites and contained a great deal of uninformative
"boilerplate" material. OUST has ongoing work with many state UST programs, such as
the Consultants Day project, designed to better specify the monitoring and reporting
requirements for corrective action.
EMSL-LV has designed several research projects specifically to assist in developing
efficient and informative monitoring procedures for the most critical operational variables
controlling the progress of remediation at UST sites. The findings from this research
include the following:
O Preliminary studies of in-situ air sparging illustrate the sensitivity of air flow paths to
heterogeneities in the porous medium. The study compared the flow paths of injected air
through medium sand and through pea gravel. The study used two large cylindrical
columns (0.8 m I.D by 1.5 m high) and compared flow paths for two types of air injection
sources: a horizontal line injection source and a vertical stand-pipe injection source. Air
was injected into the columns at 5, 10, 15, and 20 liters per minute and the arrival of the
air at the surface was monitored with a video camera.
Figure 3-12 shows the results of these preliminary studies. In the gravel column, the
line source (emplaced at the base of the column) produced a line of bubbles directly
above the source. The stand-pipe source gave a circle of bubbles covering an area about
20 cm in diameter from the stand-pipe. In both cases, the air reaching the surface was
relatively uniformly distributed, suggesting movement through the medium as discrete
bubbles. This pattern was not affected by changing the air injection rate.
3-52
-------
OJ
I
Ln
Go
15m
*********
a)
b)
0 8m
Surface patterns from sparging In horizontal
and vertical sources in a) gravel; and b) sand.
Schematic drawing of the large columns
used for the preliminary experiments
Figure 3-12. At Surface Expression of Sparging Flow Pathways.
-------
In contrast, the air reaching the surface in the sand column was erratically distributed,
as shown in the figure. With both the horizontal and vertical injection sources, the
majority of the injected air reached the surface through several discrete pathways (e.g., via
2-8 points). Neither changing the air injection rate nor pulsing the air flow produced
significant alterations in the preferential flow paths initially established. These
observations are supported by multi-phase fluid flow for media where capillary forces are
dominant.
At the small scale of the column studies, a significant portion of the injected air also
spread laterally to the column walls. This result requires that future work be conducted in
large, fully three-dimensional models to avoid these edge effects. While the observed
lateral spreading is potentially valuable in terms of field application of sparging as a
remediation technique, much additional work is required to determine how to best
monitor and model this spreading at field-scale. This problem is addressed below [B209].
D A review of present practice of in-situ air sparging revealed severe limitations in
current methods for monitoring key operating variables. The limitations in these
monitoring methods distort our perception of the volatilization and biodegradation
pathways to be enhanced by the use of in-situ air sparging and impede our ability to
selectively design improvements to such systems. At present, practitioners generally rely
on one or more of the following techniques to assess the remediation performance of in-
situ air sparging: a) monitoring dissolved contaminant concentrations; b) monitoring
dissolved oxygen concentrations; or c) monitoring effluent vapor concentrations.
Interpreting the significance of each of these methods is difficult due to their temporal
and spatial variability. Moreover, these commonly used techniques provide little insight
into phenomena fundamental to system design, such as determining the radius of influence
of the sparge well. Radius of influence is a key parameter in determining how closely the
wells must be spaced in order to effectively remove the contaminants and, consequently, is
also a key parameter in determining the cost of installing in-situ air sparging systems.
Two reported methods for determining the radius of influence of in-situ air sparging
systems are 1) using microphones in monitoring wells to observe directly that air has
reached a certain distance from the injection well; and 2) monitoring ground water levels
in order to observe the extent of the "ground water mound" formed as a result of
sparging.
The presence of bubbles in a well at a distance from a sparging well is clear evidence
of lateral air movement. However, it does not mean that the air is moving as bubbles in
the medium, nor does it provide much insight into how the air is distributed within the
medium. Because air movement will be strongly affected by heterogeneities in the
aquifer, it is likely that the air will become trapped below finer-grained layers (in much
the same way that DNAPLs become trapped on top of those layers) and as a result, the
air will move laterally. This transport pattern would probably be ineffective at removing
contaminants from the porous medium, especially if the contaminants are trapped on the
top of the low-permeability layer.
3-54
-------
With regard to the "ground water mound" created during sparging, multi-phase flow
theory indicates that for most media the fluid potentials of the air and water phases
should be independent of one another. Therefore, no sustained mound would be
expected. Moreover, it is not clear how one measures or interprets water level data in
this context. Multi-phase flow theory is contrary to some field observations of ground
water mounding. If mounds, however, are sustained during the sparging process it implies
that there must be some vertical circulation within the aquifer sustaining the mound. This
is a potentially important monitoring and design aspect of in-situ air sparging.
D Respiratory metabolism by subsurface microorganisms enhances transformation and
mineralization of hydrocarbons and evidence of the presence of this reaction in
contaminated groundwater can be gathered by monitoring changes in groundwater
chemistry and overlying gases that reflect the utilization of respiratory electron acceptors.
The effectiveness of simple soil aeration techniques for stimulating natural biodegradation
reactions can be monitored by multilevel groundwater monitoring wells. A protocol for
interpreting routine measurements of subsurface processes will provide state UST staff
and UST remediation consultants with a methodology for monitoring the progress of
contaminant degradation at UST sites where naturally occurring or enhanced
bioremediation of the plume is being used. The protocol guidelines are designed for later
transfer to computer software to assist in their use by UST staff and consultants [C-41,
B.210, B211].
~ The best way to improve feedback on subsurface remediation design processes is to
have a method to monitor performance. Determining the rate of degradation is critical to
the measuring of the success of the remediation or for input into risk analysis models to
determine the hazard to the environment if the hydrocarbon is allowed to degrade
naturally in place. Even a modest ten percent improvement in monitoring technique
could mean great cost savings for monitoring sites undergoing active remediation.
Additional savings are possible if natural bioremediation can be quantified at sites not
requiring costly active remediation.
Monitoring objectives include development and evaluation of methods to monitor the
ground water and vadose zones to measure the amount of remediation being achieved.
Methods enabling in-situ, real-time monitoring or easy sampling with field analysis of
bioremediation are being developed and should reduce the manpower required to collect
samples and perform analyses [C-38, B.212, B.213].
D An ongoing laboratory study is investigating in-situ alternatives to standard "pump and
treat" of dissolved ground water contamination. The study is investigating materials that
could be emplaced in-situ to enhance hydrocarbon removal or degradation. Preliminaiy
results indicate that peat is capable of extracting substantial amounts of either free-phase
or dissolved hydrocarbons from groundwater. Also under study are the use of specially
formulated "nutrient briquets" that are designed provide long-term, slow-release of
nutrient fertilizers to ground water.
Ongoing studies are investigating how such materials might be placed in-situ to
accelerate in-situ biodegradation without requiring intensive operation and maintenance
3-55
-------
costs. One promising design features installing a line of nutrient cores up gradient of the
dissolved contaminant source. Intensive monitoring of the resulting mixed nutrient and
ground water flow system will determine the efficiency of such cores in controlling the
migration of the dissolved hydrocarbons and will identify practical measures for the
construction and maintenance. An anticipated benefit of the project is the simplified
bioremediation of dissolved contaminant plumes too "hot" to allow completely passive
biodegradation (e.g., BTEX concentrations in the 10 - 50 ppm range) [C-42, B.214, B215].
3.2.4 EMSL-LV Corrective Action: Future Research
In contrast to many RCRA facilities or Superfund sites, most UST sites are relatively
small and it is relatively easy to predict the types and phases of contaminants that will
require remediation. For example, many researchers and practitioners are converging on
a handful of UST remediation techniques such as in-situ air sparging, vapor extraction,
and vacuum enhanced product recovery. All these techniques emphasize in-situ treatment
of hydrocarbons located at or near the capillary fringe, enhanced in-situ biodegradation of
hydrocarbon vapors, and improved recoveries of contaminants by isolating certain
stratigraphic areas of the subsurface for treatment.
Other common characteristics also predominate in UST cleanups. For example, it is
extremely difficult to model the transport of non-aqueous phase liquids (NAPLs) -
whether they are light NAPLs, like hydrocarbons, or dense NAPLs, like solvents. While
complex 3-dimensional models are essential to shaping our conceptual understanding of
important UST remediation processes and enable us to generalize from individual physical
models or field studies, the cost of obtaining adequate data for such models are likely to
keep their use beyond the reach of the majority of routine UST applications. Many
experts believe that the key to successful NAPL remediation lies not in the site-specific
application of complex models, but rather in the design of a flexible remediation approach
that can be adapted to a variety of UST settings and which can be easily modified as the
remediation progresses [B.216].
EMSL-LV has thus selected three primary focuses for its future work in Corrective
Action monitoring: (1) development of additional monitoring devices and equipment
specifically tailored to UST remediations, (2) development of guidelines for interpreting
remediation progress data, especially subsurface data, to determine how and when to
modify the remediation system to achieve continued cleanup progress, and (3)
demonstration of these devices and guidelines at field UST sites.
Future corrective action research at EMSL-LV will include the following projects.
3.2.4.1 Improved Monitoring of In-situ Air Sparging
The large-scale experimental aquifer facility at the Oregon Graduate Institute will be
used to evaluate monitoring tools for use in verifying the effectiveness of in-situ air
sparging. The planned work has two major objectives: to provide information about the
feasibility and practicality of monitoring the in-situ air injection process, and to enable
direct comparison of several monitoring tools to determine those most helpful for routine
3-56
-------
monitoring. These tools include: 1) multi-level ground water monitoring for dissolved
contamination; 2) multi-level ground water monitoring for dissolved oxygen/carbon
dioxide concentrations; 3) monitoring of air sparging/soilvapor extraction effluent; 4) use
of tracers to characterize air movement; 5) ground penetrating radar; and 6) neutron
probe analysis.
32.42 Improved Siting of Recovery Wells
For most remediation systems, wells are installed (e.g., product recovery wells, plume
control wells, vapor extraction wells) where product concentrations are estimated to be
highest and/or the hydrogeology for contaminant recovery is most favorable. Monitoring
data are essential to the proper location of and choice among such wells. As discussed,
the Aquifer Dipstick can be helpful in locating the greatest product accumulations, but
provides little information on anticipated recovery rates.
Bailer tests, in which product in a well is bailed out and then observed during
recovery, are quick and easy to do. New work is planned for developing better ways of
conducting and analyzing bailer tests as trial runs for determining whether to install
product recovery wells at a specific location. When a bailer test reveals a slow return of
product into a well, it indicates that the well location is a poor candidate for installation of
expensive oil recovery system [C-39].
32.43 Improved Feedback on the Adequacy of Product Recovery System Designs
As free phase product is recovered from UST sites, it is possible for stagnation zones
to be established within the flow field to the recovery wells. Unless these stagnation zones
are identified, and the recovery systems modified, these areas will not be sufficiently
remediated. The use of tracers to monitor the sources and flow paths of free product to
recovery wells will be investigated and tested at field sites. An anticipated benefit of this
project is the development of tracer materials and interpretive guidelines that can be used
to provide direct, observational feedback on the adequacy of the recovery system design
and performance. Such monitoring feedback could be used immediately with conventional
free product recovery systems. In addition, it could be used to evaluate and compare the
performance of innovative free product removal techniques, such as vacuum enhanced
recovery.
3.2.4.4 Improved Field Screening Procedures for Determining Feasibility of Soli
Venting at Specific UST Sites
Soil venting of gasoline hydrocarbons is applicable at many UST sites, but Field
specific determinations of its potential applicability are unnecessarily delayed. Past work
at the University of Connecticut has shown the value of conducting air permeability tests
simultaneously with conducting soil vapor surveys, since the air permeability measurements
assist in correct interpretation of the source and strength of the vapor readings. Future
work will investigate air permeability measurements tailored for application to UST sites
for the purpose of assessing the feasibility of venting during the initial site investigations.
3-57
-------
3.2.4.5 In-situ Field Respiration Tests for Assessing the Bioactivitv of LIST Release
Sites
Many UST sites are expected to have significant biological activity that can assist in
the degradation of subsurface hydrocarbons. As with soil venting, assessing this bioactivity
is often unnecessarily delayed. Future work will develop UST specific in-situ respiration
tests to be done in conjunction with a one well vent test of air permeability for soil
vacuum extraction. The test procedure will monitor oxygen uptake and carbon dioxide
production rates, and provide guidelines for assessing bioactivity potential within the
context of background soil respiration.
3-58
-------
SECTION 4
TECHNOLOGY TRANSFER
4.1 RREL TECHNOLOGY TRANSFER PROGRAM
Technology transfer involves the exchange of technical information between research-
ers and the UST user community. Section 3.1 outlined RREL's current and planned re-
search program for the development of new methods and techniques for assessing and
cleaning up contamination from leaking underground storage tanks. As advances in the
state of the art are made, this knowledge is conveyed to the decision makers who will
ultimately be responsible for implementing these developments at LUST sites. The goal
of technology transfer is to communicate research results to the appropriate end user in
an effective, efficient and timely manner.
RREL believes that to be effective, technology transfer must be an integral part of the
planned research project, not just an add-on task to be accomplished after completion of
the technical work. Further, the resources (staff and financial) necessary to carry out the
technology transfer activities must be dedicated to the project. The importance of
technology transfer to the UST Research Program has always been recognized; however,
to confirm its commitment to effective technology transfer, RREL is requiring every Work
Plan or research proposal to include a section specifically addressing technology transfer.
The plan should identify the target audience, specify the tools that will be developed for
these audiences, and show the schedule and resources to be committed.
The two key elements of an effective technology transfer strategy are as follows:
1) Identification of the end users and their involvement in the planning and
progress of research projects.
2) Development of useful and timely research products that are matched to
the target audience.
Involving the end user from the start of a project ensures that research funds are being
spent wisely (i.e., that the planned research is needed) and that the user has access to the
information as it becomes available. Such involvement may include participation in expert
workshops to identify research needs or the review and critique of reports and interim
deliverables. Research products that are matched to the needs and technical skills of the
target audience and are disseminated quickly improve the efficiency of information
transfer.
4-1
-------
As shown in Figure 4-1, the target audiences for UST research products may include
any of the following:
OUST Program Office
Equipment manufacturers
Engineering consultants/contractors
Scientific community (academic, industrial and governmental researchers)
Tank owners/operators
Federal, state, and local regulators
Although the OUST Program Office is an important ORD client, research products
generally target the end users directly. If multiple end users are identified, more than one
product may be required. For example, a technical bulletin on SVE that identifies the
important site assessment characteristics would be useful to a State regulator who must
evaluate a corrective action plan, whereas a design reference manual would benefit the
consulting engineer who must prepare the detailed bid and specifications package.
4.1.1 RREL Technology Transfer Tools: Past and Current
RREL currently uses a variety of familiar tools to effect technology transfer. These
include:
Publications
Workshops, seminars, and conferences
State/Regional technical assistance teams
Computerized information systems
Cooperative agreements and Interagency Agreements
Federal Technology Transfer Act (FTTA) agreements
Training courses
Publications include research reports, project summaries, technical bulletins, journal
articles, newsletters, proceedings, guidance documents, and field guides. Appendix B
presents a partial bibliography of publications that have been generated over the last
several years. Most of these publications are available directly from the Agency or
through the National Technical Information Service (NTIS). Of note are the engineering
bulletins on specific treatment technologies [B.84-B.90]. The EPA's Center for
Environmental Research Information (CER1) maintains an UST mailing list with more
than 5000 names.
Workshops, seminars, and conferences provide an interactive forum for exchange of
technical information. A research symposium is hosted annually by RREL to present its
important research findings [B.56-B.75]. RREL researchers also participate in OUSTs
National UST/LUST Conferences [B.76-B.83], as well as numerous other
National/International conferences and specialty work group meetings between the
Laboratory and Regional and State offices. RREL is currently involved in developing
4-2
-------
ORD
OUST
Regulators
Equipment
Manufacturers
Tank Owners/
Operators
Scientific
Community
Engineering
Consultants/Contractors
Figure 4-1. Target Audiences for UST Research Products.
4-3
-------
training materials and conducting "train-the-trainer" courses on innovative corrective action
technologies for LUST sites. The courses are being developed in cooperation with OUST,
and several Regions for their respective State UST Program Managers. The goal of these
courses is to improve the ability of EPA and State staff to direct, review, and approve site
assessment reports and corrective action plans recommending these technologies. The
UST Test Apparatus has also been used for "hands on" training of EPA Regional and
state and local agency UST personnel in the area of tank and pipeline inspection and leak
detection technology.
State and Regional technical assistance teams such as EPA ORD's Superfund
Technical Assistance Response Team (START) provide technical support for assessing
and cleaning up petroleum- and hazardous waste-contaminated soil and ground water.
These teams comprise technical experts from across ORD's research programs who draw
upon their research experience to solve real-world problems; several of RREL's UST
Program staff are members of these teams. In addition, and as discussed in Sections 2
and 3, RREL's UST researchers have increased activity in site-directed research and in
providing technical support to EPA Regions (II, V, VII, IX) and states for the planning,
design, and field evaluation of innovative technologies at actual LUST sites.
The use of electronic data bases and automated information systems facilitates the
search and retrieval of information from past and ongoing remediation activities and
laboratory and field trials. RREL's Computerized On-Line Information System (COLIS),
mentioned previously in Section 2, [C-33, B.47-B.55], was developed in 1987 and has been
operated, maintained, updated, and expanded on a continuous basis. In addition, other
literature search data bases, treatability data bases, transport and fate data bases, cost
models, expert systems, and an expert contact list are accessible through the Alternative
Treatment Technology Information Center (ATTIC).
Cooperative Agreements and Interagency Agreements provide opportunities for joint
research involving government, industry, and academia. These agreements establish a
direct technology transfer link between researchers and the end users and increase the
available resource pool. The RREL currently funds related research under cooperative
agreements with the Oregon Graduate Institute, Princeton University, Drexel University,
the University of Cincinnati, the University of Michigan, and is planning future work with
the Industry/University Cooperative Center for Research for Hazardous and Toxic
Substances (which comprises the New Jersey Institute of Technology, other universities,
and a consortium of Fortune 100 companies). Interagency Agreements are also being
negotiated with DOD, DOE and DOT.
The Federal Technology Transfer Act enables EPA to enter into cooperative research
and development agreements with selected industrial partners to develop, improve,
maintain, modify, and market technologies developed with Agency funds. Technology
offerings are advertised in the Commerce Business Daily, and potential technology
partners are required to submit a business plan /partnership proposal. This mechanism is
being used to transfer the UST Test Apparatus to the commercial sector for further
development of leak detection methods. RREL is also involved in an FTTA Agreement
with Shell Oil Company to develop and demonstrate a SVE technology screening model.
4-4
-------
4.12 Enhancing RREL Technology Transfer: Future
Although the tools described in the preceding subsection have proven useful, RREL is
constantly seeking ways to enhance technology transfer. The following discussion presents
RREL's plan to transfer information to the end user in a more effective, efficient and
timely manner.
The final deliverable for most research projects is a research report/project summary.
Often however, these documents are not available until long after completion of the
technical work. One method of disseminating research results more expeditiously is the
use of newsletters and technical journals. These tools can shorten the time required for
review and publication of the data by several months and typically result in much wider
distribution of the information. They will be used more liberally in the future to present
interim results, to update progress, and to announce upcoming research projects.
Many research projects result in reports that are long and highly technical. Often, the
documents can respond to the needs of several audiences; however, the end users do not
have the time, ability or inclination to selectively read and comprehend the data and
calculations contained therein. A videotaped lecture covering select material in the report
will be used to aid in the transfer of such information. With this approach, scientific
principles can be explained, key points emphasized, and difficult material clarified through
questions and answers. Although it should be well rehearsed, the video need not be
expensive, highly polished, or require the services of a professional narrator.
For technology evaluation projects, difficulties are often encountered in locating sites
where the projects can be conducted and in obtaining the necessary permits and
approvals. Regional technical assistance programs can expedite joint projects with
industry (e.g., major oil firms) by streamlining the regulatory process and assisting with the
development of quality assurance plans. The RREL is developing model QAPPs for
various corrective action technologies (e.g., air sparging, thermal desorption,
bioremediation) to encourage (rather than discourage) industry involvement.
4.13 RREL Technology Transfer Accomplishments
The accomplishments of RREL's UST Research Program to date are due in part to
the effective use of the above mentioned technology transfer techniques. This subsection
addresses select projects which incorporated these technology transfer planning techniques
and tools and resulted in the success of the projects.
4.13.1 Volumetric Leak Detection Methods Evaluation
The Volumetric Leak Detection Methods Evaluation project [C-4] influenced the
entire leak-detection industry to change its approach to testing tanks and evaluating leak-
4-5
-------
detection systems. As a result, almost all of the leak-detection systems now in use meet or
exceed EPA regulatory standards.
The success of the methods evaluation project was due to the active involvement,
critique, and communication between the EPA, contractor and research organizations,
petroleum trade associations such as the American Petroleum Institute, and manufacturers
of volumetric leak-detection equipment. The project was widely publicized through
announcements in the Commerce Business Daily, articles in various trade magazines, and
direct mailings. It was also peer-reviewed by experts in the scientific community.
Throughout the course of the project, the vendors of leak-detection equipment were in
direct communication with the engineers who were conducting the evaluation. The RREL
held several meetings with the vendors, including a four-hour meeting with each individual
vendor at the completion of the program but before the finalization and reporting of the
results. At these meetings, the evaluation results of the vendor's system were discussed
along with suggestions for improving the performance of the system.
A significant effort was also made to transfer the results of the methods evaluation
project to Federal and State regulators, consulting engineers, and tank owners. Four 2-
day and four 1-day seminars were given at eight cities across the country. In addition, a
simplified version of the 1000-page final report was published through CERI. The results
of this work were widely published in journal papers, symposium papers, and technical
reports. Both RREL and OUST used many tools to effect technology transfer (special
seminars, final reports, brochures, project summaries, journal papers, conferences and
symposia presentation and papers); however, the effectiveness of technology transfer
ultimately was a result of the involvement of the vendors in all aspects of the evaluation.
4.13.2 Computerized On Line Information System (CPUS')
The experiences of UST program managers at all levels of government and the
consulting community vary widely. Information that would allow these personnel to obtain
the immediate benefit of the experiences of others involved in UST cleanup actions and
other hazardous waste site remediations is extremely useful. RREL designed, fabricated,
and is currently operating a Computerized On-line Information System (COLIS) [C-32].
Within COLIS, is a consolidated system housing several different databases. The
databases contain current technical information and bibliographic references concerning
corrective actions taken at leaking underground storage tank sites, hazardous waste sites,
and spill responses. The system is "user friendly" and may be accessed 24 hrs/dayfrom
any personal computer. RREL has developed an Information Package on COLIS that
contains a Users Guide, Fact Sheet, and Access card, however, most users find the system
easy enough to use without it. The system was completed in 1987 and is updated weekly.
Over the past five years, COLIS has served more than 10,000 users and provided technical
documents to over 25% of the callers.
The success of COLIS is not only demonstrated by extensive usage, but also by the
numerous related spinoff projects that were completed at the request of EPA Regions and
State UST Program Offices. Based on COLIS, a national management and prioritization
4-6
-------
system was designed and fabricated for remediating leaking USTs on Native American
lands. In addition, a state UST management program was built and transferred to several
UST state programs to help track and remediate both UST and LUST sites.
4.133 Pipeline Protocol
In coordination with OUST, RREL prepared a standard test procedure for evaluating
the performance of pipeline leak-detection systems for pressurized pipelines [C-6], which
was subsequently used to evaluate six different types of pipeline leak detectors. The
procedure, one of seven in a series, was published and distributed by OUST directly to
manufacturers of pipeline leak detectors for their use in evaluating the performance of
their equipment. These manufacturers had the opportunity to review the written
evaluation procedure twice before it was finalized. A 4-hour technical presentation, which
described the evaluation procedure, was delivered to more than 50 manufacturers and
vendors of leak-detection equipment for their review and comment in a 2-day OUST-
sponsored workshop. These comments were incorporated into the procedure before it
was finalized and published. All vendors of pipeline leak-direction equipment or services
have had their equipment evaluated using this procedure, and all tank owners purchasing
pipeline leak-detection equipment or services receive a summary form from the vendor
presenting the results of the evaluation.
42 EMSL-LV TECHNOLOGY TRANSFER PROGRAM
Technology transfer refers to those activities which provide a mechanism for making
research results known to those people who can benefit from the findings. For UST
research, the primary audience for technology transfer are federal, regional and state UST
staff; contractors who provide leak detection, site investigation and corrective services; and
the regulated community. Without effective transfer of research results, UST leak
detection, investigation and remediation activities will be more costly and of lower quality
than might be achieved using up-to-date methods and techniques.
To address the diverse needs of its UST audience, EMSL-LV is pursuing four
principle methods of technology transfer:
1) Building new research capability and resource centers at universities.
2) Sponsoring development of standard methods for UST investigations and
remediation.
3) Sponsoring development of new tools for commercialization.
4) Participating in outreach activities, e.g., newsletters, workshops, and in developing
training courses in cooperation with OUST.
Each of these methods is discussed below.
4-7
-------
42.1 Building New Research Capabilities
The science of non-aqueous phase liquid (NAPL) contaminant hydrogeology is still
very young, having only begun in the early 1980's - such as Freeze and Cherry's
Hvdrogeologv. published in 1979 - do not even mention NAPLs (more familiarly known
in UST parlance as "free product") as a source of ground water contamination. There
have been significant scientific advances in our understanding of NAPL contamination in
the last decade. There are still, however, very few researchers capable of conducting basic
science on the assessment and remediation of LNAPL contamination. This lack of
expertise severely limits the pace of new experimental and field work. Such work could
greatly enhance the effectiveness of the virtually new UST investigation and remediation
industry that has been created in response to the 1988 federal regulations.
To help support the development of research capability in this area, the bulk of
EMSL's work is conducted by university researchers under cooperative agreements.
EMSL currently has 7 cooperative agreements in place, supporting approximately 14
faculty and and 21 to 28 graduate students. This arrangement increases our potential to
conduct new primary research at low cost to the Agency. The availability of EPA-
sponsored research at universities also acts as a catalyst to leverage additional research
funding from other sources. EMSL-LV is participating in cooperative UST research with
the U.S. Air Force and the U.S. Geological Survey. Major oil companies and Battelle
Northwest have recently proposed cooperatively designed projects with EMSL staff and
EMSL-sponsored university professors as co-researchers.
The availability of UST expertise within universities has also fostered a mutually
beneficial working relationship between EPA supported researchers and state UST staff.
For example, EMSL-LV sponsored researchers at five different universities have
independently established a working relationship with the UST program in their home
state. These researchers and their students are now able to provide training, review or
input to the state's regulatory program.
4.2.2 American Society for Testing and Materials (ASTM) UST Standards
The American Society for Testing and Materials (ASTM) has been developing
consensus standards for a wide range of industrial and geotechnical applications. Since
1987, EMSL-LV has supported ASTM in its development of standards for many aspects
of hydrogeologic investigations and site remediation activities, including soil and ground
water monitoring methods. At present, 11 standards have been finalized and 46 are under
review.
In 1990, two ASTM subcommittees were established specifically for UST work: the
UST Leak Detection and the UST Site Assessment and Remediation Subcommittees.
Their work is conducted by the Underground Storage Tank Subcommittee of the new E50
Committee under a cooperative agreement with ASTM. The results of the committee's
recent efforts in UST Corrective Action, entitled a Guide to Remediation of Petroleum
Releases, is currently undergoing red-border review within the Agency and is scheduled
for public release in May 1992.
4-8
-------
As a tool for technology transfer, EMSL-LV has found that supporting development
of ASTM standards through funding and staff participation confers the following benefits:
a) ASTM standards are readily accepted and implemented by practitioners because
these standards reflect the consensus of researchers, regulators and UST vendors.
ASTM standards are regarded as highly credible.
b) The ASTM process enables EPA-ORD to help set the agenda for standards
development, without incurring the full monetary and staff costs to produce
guidelines and standards.
c) ASTM standards provide state UST programs with a credible source of guidelines
and protocols that they can adopt by reference into their UST regulations, thereby
economizing on scarce UST program resources.
d) ASTM standards are reviewed and revised every five years, thus ensuring that the
standards will be updated to reflect new findings and future improvements. EMSL-
LV sponsorship of ASTM-UST work is anticipated to continue for as long as there
is an UST research program.
4.23 Sponsoring Development of New Tools for Commercialization
EMSL-LV has found the development of rapid, accurate in-situ measurement devices
invaluable to improving our understanding of subsurface hydrocarbon processes. Such
measurement methods not only give us more immediate feedback on subsurface
conditions, but they can also be less expensive and difficult to operate than the
conventional methods they replace.
Although product commercialization is not the primary focus of EMSL UST research,
two devices developed under EMSL sponsorship have been patented and are now
commercially available for use in UST investigations. These are the Lab-in-a-Bag
(commercialized under an FTTA agreement) and the Aquifer Dipstick. (The uses and
contributions derived from these devices are described in Sections 3.)
Several new measurement methods under development by EMSL-LV also show high
potential for commercialization. These include: hydrophobic well packs for product
recovery, tracers for monitoring product recovery; immunoassay test-kits for hydrocarbon
contaminants; and combination sensors for monitoring in-situ bioremediation processes.
As before, EMSL-LVs primary interest in product commercialization will be to transfer
prototypes to the private sector as quickly as possible to free up federal resources for new
work.
4.2.4 Outreach Activities
42.4.1 Tank Issue Papers
The majority of EMSL-LVs research projects are transferred to the public through
publication in peer-reviewed journals or presentations at national conferences.
Recognizing the time required for article publication and the inability of many state UST
staff to attend conferences, EMSL-LV has produced a series of UST "Tank Issue papers".
4-9
-------
These Issue papers are patterned along the lines of educational newsletters used by
university extension programs.
Each Tank Issue paper describes the key findings and application of recent research
and reported field experiments. Issue papers are not intended to replace the peer review
and formal publication process. They are, however, intended to transfer, as rapidly as
possible, key findings and trends in UST research. Issue papers have been written by
individuals and by expert panels. Each issue paper is reviewed to ensure that it represents
the "state-of-the-knowledge" on relevant UST topics.
The issue papers are published and distributed by CER1 to UST programs, the
regulated community, and leak detection and remediation consultants. The current
mailing list reaches over 4,000 targeted customers. EMSL-LV has currently budjgeted this
activity through FY *95 and is exploring ways to cooperate with other laboratories for
production of the issue papers.
4.2.4.2 Workshops and Presentations at National Conferences
EMSL-LV has sponsored or participated in a number of workshops and presentation
of research findings at national conferences. These include:
Two-day Symposium on Leak Detection for USTs, Oct. 1988. Gold Coast Casino, Las
Vegas. (First day: internal tank testing by RREL, Edison. Second day: External
monitoring by EMSL-LV).
Numerous presentations of EMSL-LV sponsored research at the Annual
Hydrocarbons in Groundwater Conference, sponsored by National Water Well
Association and EPA. 1987 through 1991.
Presentations at the Annual Underground Storage Tank Conference for state UST
staff, sponsored by OUST, 1988 - 1990.
EPA/API Field Monitoring of Bioremediation Workshop - Sept 1990.
4.2.4.3 Training Programs Co-Sponsored bv OUST
Due to the enthusiastic reception by state UST staff to presentations of research
findings stemming from EMSL-LV*s three year cooperative agreement with the University
of Connecticut, OUST and EMSL-LV teamed up to provide follow-up training courses to
state staff. Two courses have been developed and are very popular. These are the:
Soil Vapor Survey "Boot Camp:" This intensive 4 1/2 day course has been presented
to over 140 students (primarily state UST regulators) in EPA Regions 2,4 and 5.
Lab-in-a-Bag Training Course: This 1 l/2day training has been presented in six states
( SC, MN, MI, IL, WI and CT) to 132 students (again, primarily state UST regulators
and UST consultants) [B.217, B.218].
4-10
------- |