xvEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/R-94/521
September 1998
Terra-Kleen Response
Group, Inc.
Solvent Extraction
Technology
Innovative Technology
Evaluation Report
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
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EPA/540/R-94/521
September 1998
Terra-Kleen Response Group, Inc.
Solvent Extraction Technology
Innovative Technology Evaluation Report
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Printed on Recycled Paper
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Notice
The information in this document has been funded by the U. S. Environmental Protection Agency (EPA) under Contract Nos.
68-CO-0047 and 68-C5-0037 to Tetra Tech EM Inc. (formerly PRC Environmental Management, Inc.). It has been subjected
to the Agency's peer and administrative reviews and has been approved for publication as an EPA document. Mention of trade
names or commercial products does not constitute an endorsement or recommendation for use.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's land, air, and water
resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a
compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this man-
date, EPA's research program is providing data and technical support for solving environmental problems today and building a
science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our health, and
prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for investigation of technological and
management approaches for reducing risks from threats to human health and the environment. The focus of the Laboratory's
research program is on methods for the prevention and control of pollution to air, land, water and subsurface resources; protec-
tion of water quality in public water systems; remediation of contaminated sites and ground water; and prevention and control of
indoor air pollution. The goal of this research effort is to catalyze development and implementation of innovative, cost-effective
environmental technologies; develop scientific and engineering information needed by EPA to support regulatory and policy
decisions; and provide technical support and information transfer to ensure effective implementation of environmental regula-
tions and strategies.
This publication has been produced as part of the Laboratory's strategic long-term research plan. It is published and
made available by EPA's Office of Research and Development to assist the user community and to link researchers with their
clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
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Abstract
Terra-Kleen Response Group, Inc. (Terra-Kleen) has developed a solvent extraction technology to remove organic
contaminants from soil. The IT. S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation
(SITE) Program evaluated the performance of this technology during a demonstration at Site 4 of Naval Air Station North
Island (NASNI) in San Diego, California in May and June 1994. This Innovative Technology Evaluation Report (ITER)
describes the technology and environmental requirements, an economic analysis of treatment costs, and an evaluation of the
performance of the technology during the SITE demonstration.
The Terra-Kleen technology employs a proprietary solvent that extracts organic contaminants from contaminated soil.
Following this extraction, the organic-laden solvent is then filtered and purified, using a proprietary purification unit.
Regenerated solvent is continuously recycled through the contaminated soil until a target cleanup level is achieved. Any
solvent remaining in the treated soil is removed using vacuum extraction and biological treatment. Terra-Kleen claims that
its treatment process removes polychlorinated biphenyls (PCB), petroleum hydrocarbons, chlorinated hydrocarbons,
polynuclear aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzo-p-furans, and metals from
contaminated soil.
An initial treatability study was conducted to determine the technology's ability to remove PCBs from soil collected from
three sites that was shipped to Terra-Kleen's testing facility in Okmulgee, Oklahoma. These soils were obtained from Sites
4 and 6 at Naval Air Station North Island (NASNI) in Coronado, California, and from a site in Anchorage, Alaska. Results
from treated soil showed that PCB removal efficiency ranged from 95.3 to 99.1 percent. PCB concentrations in treated soils
from both the NASNI sites were reduced to below the Toxic Substances Control Act incineration equivalency concentration
of 2 milligrams per kilogram (mg/kg). The Alaskan soil contained a higher percentage of fines, clay, and natural organic
matter, a fact that contributed to the higher number of extraction cycles needed to reduce PCB concentrations to 6.0 mg/kg.
The Terra-Kleen technology was demonstrated under the SITE Program at NASNI in May and June 1994. The
demonstration provided information on the performance and cost of the Terra-Kleen technology. Analytical results for
treated soil showed that PCB concentrations of 144 mg/kg in contaminated soil were decreased to less than 1.71 mg/kg with
& significance level of 0.05, for an overall removal efficiency of 98.8 plus or minus 0.1 percent. Untreated and treated soils
were also analyzed for parameters such as oil and grease, volatile organic compounds, semivolatile organic compounds,
dioxins, and furans to determine the Technology's ability to remediate soils contaminated with these constituents. Sampling
results indicated that the technology removed 66.3 plus or minus 5.47 percent of the oil and grease, and reduced
hexachlorodibenzofurans and pentachlorodibenzofurans by 92 plus or minus 0.82 percent and 76 plus or minus 5.28 percent,
respectively.
After the SITE demonstration, the SITE Program collected soil samples during a full-scale remediation of pesticide-
contaminated soils at Naval Communication Station Stockton in Stockton, California. Soil at different sites on the installation
were contaminated with DDD, DDE, and DDT at concentrations of 150, 50, and 600 mg/kg, respectively. Percent removals
for all three pesticides ranged from 99.4 to 99.9 percent.
An economic analysis for the Terra-Kleen SITE demonstration was based on theoretical sites containing 500, 2,000, and
10,000 cubic yards of contaminated soil, respectively. The costs per ton were calculated as $300, $210, and $170 for each
of the three sites, respectively. This unit cost included the estimates for remediation, site preparation, residuals shipping,
handling, and disposal.
IV
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Contents
Acronyms, Abbreviations, and Symbols ix
Conversion Factors xi
Acknowledgments xii
Executive Summary 1
1 Introduction 3
1.1 Brief Description of the SITE Program and Reports 3
1.2 Innovative Technology Evaluation Report 4
1.3 Technology Description 4
1.3.1 Soil Dewatering 6
1.3.2 Soil Treatment 6
1.3.3 Solvent Regeneration 6
1.3.4 ResidualSolvent Removal 7
1.4 Key Contacts 7
2 Technology Applicability 9
2.1 Technology Performance Compared to National Contingency Plan Evaluation Criteria....9
2.1.1 Overall Protection of Human Health and the Environment 9
2.1.2 Compliance With Applicable or Relevant and Appropriate Requirements 11
2.1.3 Long-Term Effectiveness and Permanence 11
2.1.4 Reduction in Toxicity, Mobility, or Volume Through Treatment 12
2.1.5 Short-Term Effectiveness 12
2.1.6 Implementability 13
2.1.7 Cost 13
2.1.8 Community Acceptance 13
2.1.9 State Acceptance 13
2.2 Technology Performance Compared to ARARs 13
2.2.1 Resource Conservation and Recovery Act 14
2.2.2 Clean Air Act 14
2.2.3 Toxic Substances Control Act , 14
2.2.4 Occupational Safety and Health Act 16
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Contents (continued)
2.2.5 Hazardous Materials Transportation Act 16
2.3 Operability of the Technology 16
2.4 Applicable Wastes 17
2.5 Material Handling Requirements 17
2.6 Site Support Requirements 17
2.7 Limitations of the Technology 18
3 Treatment Effectiveness 19
3.1 Background , 19
3.1.1 NASNI 19
3.1.2 Site 4 22
3.1.3 Geology and Soils 22
3.1.4 Contamination at Site 4 22
3.2 Demonstration Objectives and Approach 22
3.3 Sampling and Analytical Procedures 26
3.3.1 Demonstration Preparation 26
3.3.2 Sampling and Analysis Program 26
3.3.3 Quality Assurance and Quality Control Program 28
3.4 Demonstration Results and Conclusions 29
3.4.1 Primary Objective 29
3.4.2 Secondary Objective S1 30
3.4.3 Secondary Objective S2 30
3.4.4 Secondary Objective S3 33
3.4.5 Secondary Objective S4 33
3.4.6 Secondary Objective S5 34
4 Economic Analysis 35
4.1 Basis of Economic Analysis 35
4.2 Assumptions for the Economic Analysis 35
4.3 Factors Affecting Costs 36
4.4 Results of the Economic Analysis 37
4.4.1 Site Preparation Costs 37
4.4.2 Permitting and Regulatory Requirements 37
4.4.3 Startup 37
4.4.4 Equipment 39
4.4.5 Labor 39
4.4.6 Consumables and Supplies 39
4.4.7 Utilities 40
vi
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Contents (continued)
4.4.8 Effluent Treatment and Disposal 40
4.4.9 Residuals and Waste Shipping and Handling 40
4.4.10 Analytical Services 41
4.4.11 Maintenance and Modifications 41
4.4.12 Demobilization 41
5 Technology Status 42
6 References 43
Appendix
A Terra-Kieen Technology Treatability Study
B Terra-Kieen Technology Full-Scale Implementation
C Vendor Claims for the Terra-Kieen Technology
VII
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Figures
1-1 Schematic Diagram of the Terra-Kleen Technology 5
3-1 Location of NASNI 20
3-2 Site 4 Location Map 21
3-3 NASNI Site 4 Demonstration Location 23
3-4 NASNI Site 4 PCB Contamination and Excavation Area 25
3-5 Terra-Kleen Sampling Locations 27
Tables
2-1 NCP Evaluation Criteria for the Terra-Kleen Technology 10
2-2 Federal and State ARARs for the Terra-Kleen Technology 15
3-1 Maximum and Average Contaminant Concentrations 24
3-2 PCB Aroclor 1260 Analytical Results 31
3-3 Particle Size Distribution Analytical Results 31
3-4 Oil and Grease Analytical Results 32
3-5 Furan Analytical Results 32
4-1 Costs Associated with the Terra-Kleen Technology 38
viii
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Acronyms, Abbreviations, and Symbols
wg/kg
ARAR
bgs
CAA
CERCLA
CFR
DDD
DDE
DDT
DUP
EPA
GC
HMTA
HxCDF
IRP
ITER
kWh
LDR
mg/kg
mil
NASNI
NCP
NCS Stockton
NELP
mm
mL
MS/MSD
ORD
OSHA
OSWER
Micrograms per kilogram
Applicable or relevant and appropriate requirement
Below ground surface
Clean Air Act
Comprehensive Environmental Response,
Compensation, and Liability Act
Code of Federal Regulations
4,4'-Dichlorodiphenyldichloroethane
4,4'-Dichlorodiphenyldichloroethene
4,4'-Dichlorodiphenyltrichloroethane
Duplicate
U.S. Environmental Protection Agency
Gas chromatography
Hazardous Materials Transportation Act
Hexachlorodibenzofuran
Installation Restoration Program
Innovative Technology Evaluation Report
Kilowatt hours
Land disposal restrictions
Milligrams per kilogram
One thousandth of an inch
Naval Air Station North Island
National Contingency Plan
Naval Communication Station Stockton
Navy Environmental Leadership Program
Millimeter
Milliliter
Matrix spike/matrix spike duplicate
Office of Research and Development
Occupational Safety and Health Administration
Office of Solid Waste and Emergency Response
ix
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Acronyms, Abbreviations, and Symbols (continued)
PAH
PRC
PCB
PCDD
PCDF
PeCDF
PPE
ppm
QA/QC
QAPP
RCRA
SARA
SWDIV
SITE
SVOC
Terra-Kleen
TSCA
VOC
Polynuclear aromatic hydrocarbon
PRC Environmental Management, Inc.
Polychlorinated biphenyl
Polychlorinated dibenzo-p-dioxin
Polychlorinated dibenzo-/?-furan
Pentachlorodibenzofuran
Personal protective equipment
Parts per million
Quality assurance/quality control
Quality assurance project plan
Resource Conservation and Recovery Act
Superfund Amendment and Reauthorization Act
Southwest Division, Naval Facilities Command
Superfund Innovative Technology Evaluation
Semivolatile organic compound
Terra-Kleen Response Group, Inc.
Toxic Substances Control Act
Volatile organic compound
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Conversion Factors
To Convert From
To
Multiply By
Length
inch
foot
mile
centimeter
meter
kilometer
2.54
0.305
1.61
Area:
square foot
square meter
0.0929
acre
square meter
4,047
Volume:
gallon
cubic foot
liter
cubic meter
3.78
0.0283
Mass:
pound
kilogram
0.454
Energy:
kilowatt-hour
megajoule
3.60
Power:
kilowatt
horsepower
1.34
Temperature: ^Fahrenheit - 32) "Celsius
0.556
XI
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Acknowledgments
This report was prepared under the direction of Mr. Mark C. Meckes, U.S. Environmental Protection Agency (EPA) Superfund
Innovative Technology Evaluation Program project manager in the National Risk Management Research Laboratory,
Cincinnati, Ohio. EPA and its contractor, PRC Environmental Management, Inc., acknowledge and appreciate the support and
assistance of the Navy Environmental Leadership Program and the Navy staff at Naval Air Station North Island. We also wish
to thank Dr. Caroline Acheson, and Mr. Dennis L. Timberlake of EPA for reviewing and commenting on the technical accuracy
of this document.
xn
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Executive Summary
This report presents the results of a U.S. Environmental
Protection Agency (EPA) Superfund Innovative Technology
Evaluation (SITE) Program demonstration of a solvent
extraction technology developed by Terra-Kleen Response
Group, Inc. (Terra-Kleen). The Terra-Kleen technology
was demonstrated in May and June 1994 at Site 4 of Naval
Air Station North Island (NASNI) in San Diego, California.
EPA developed the SITE Program in response to the
Superfund Amendments and Reauthorization Act of 1986.
The program's primary purpose is to facilitate the use of
alternative treatment technologies to remediate hazardous
waste at sites throughout the nation. To this end, reliable
performance and cost data on innovative technologies are
developed during demonstrations where the technology is
used to treat specific types of waste.
After completing each demonstration, EPA publishes an
Innovative Technology Evaluation Report (ITER), a
document designed to aid decision-makers in evaluating the
demonstrated technology for consideration as an applicable
cleanup option. The ITER includes a description of the
technology and environmental requirements, an economic
analysis of treatment costs, and the results of the
demonstration.
The Terra-Kleen solvent extraction technology uses a
proprietary extraction solvent at ambient temperatures to
transfer organic contaminants from soil to a liquid phase.
The organic-laden solvent is then filtered and passed
through a proprietary purification unit to remove the organic
contaminants from the solvent. The regenerated solvent is
continuously recycled through the contaminated soil until a
desired cleanup level is attained. When all required
extraction cycles have been completed, the treated soil is
subjected to vacuum extraction and biological treatment to
remove residual solvent. The developer claims that the
following compounds can be removed:
Polychlorinated biphenyls (PCB)
• Petroleum hydrocarbons
• Chlorinated hydrocarbons
• Polynuclear aromatic hydrocarbons
• Polychlorinated dibenzo-/?-dioxins
• Polychlorinated dibenzo-£>-furans
• Metals
The Terra-Kleen technology's ability to remove PCBs from
soil was initially demonstrated during a SITE treatability
study conducted at Terra-Kleen's testing facility in
Okmulgee, Oklahoma. The results from the treatability
study are presented in Appendix A. To determine if the
technology was capable of removing chlorinated pesticides
from soil, EPA collected soil samples during a full-scale
remediation at Naval Communication Station Stockton in
Stockton, California. The analytical results of the pesticide
sampling during the full-scale remediation are presented in
Appendix B.
The primary objective of the SITE demonstration was to
determine whether the Terra-Kleen technology could
reduce PCBs (specifically, Aroclor 1260) to below the
Toxic Substances Control Act (TSCA) incineration
equivalency concentration for PCBs in soil of 2 milligrams
per kilogram (mg/kg), on a dry-weight basis. During the
SITE demonstration, the Terra-Kleen technology reduced
PCB concentrations in the soil from an average of 144 mg/
kg to less than 1.71 mg/kg at the 0.05 significance level and
had an overall removal efficiency of 98.8 ±0.1 percent.
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The secondary objectives of the demonstration were as
follows:
• Determine the characteristics of untreated soils that
may affect technology performance (moisture con-
tent, particle size distribution, and oil and grease
content)
• Determine if the Terra-Kleen technology removes
volatile organic compounds (VOC), semivolatile
organic compounds (SVOC), oil and grease, diox-
ins, and fiirans from soils
• Determine if, following treatment, the PCB con-
centration in the regenerated solvent is less than
the TSCA incineration equivalent concentration for
PCBs of 2 mg/kg to document that the solvent can
be reused
• Document the operating conditions of the
TerraKleen technology
• Estimate the capital and operating costs of treating
soils and project additional capital and operating
costs for full-scale operations
During the SITE demonstration, untreated and treated soils
were analyzed for moisture content, particle size distribution,
and oil and grease content because Terra-Kleen claims that
these parameters may affect technology performance.
According to Terra-Kleen, elevated levels of these
parameters may increase the number of solvent extraction
cycles required to reduce contaminants to concentrations
below site-specific cleanup levels. Analyses of untreated
soil at Site 4 indicated a moisture content of 0.83 percent
(mass of water relative to total soil mass); a particle size
distribution of 80 percent sand, 15 percent gravel, and 5
percent silt and clay; and an overall oil and grease
concentration of 780 mg/kg. Under these soil conditions, the
technology performance did not appear to be affected, since
11 solvent extraction cycles were required to reduce the
PCB concentrations in soil to below the 2 mg/kg goal.
Untreated and treated soil also was analyzed for oil and
grease, VOCs, S VOCs, dioxins, and furans to determine the
ability of the Terra-Kleen technology to reduce the
concentrations of these constituents. However, because
the concentrations of VOCs, SVOCs, and dioxins were
below the method detection limit in the untreated soil
samples, the ability of the technology to remove these
constituents could not be evaluated. The technology was
effective in removing oil and grease and furans,
specifically hexachlorodibenzofuran (HxCDF) and penta-
chlorodibenzofurans (PeCDF). Sampling results indicated
that the technology removed 66.3 ± 5.47 percent of the oil
and grease content, and reduced HxCDF and PeCDF by 92
± 0.82 percent and 76 ± 5.28 percent, respectively.
Regenerated solvent was analyzed to determine its
acceptability for reuse at other contaminated sites.
Analytical results indicated that the PCB concentration in
the solvent was below the method detection limit of 0.08
mg/kg. Since the PCB concentration in the solvent was
less than the TSCA incineration equivalency concentration
for PCBs of 2 mg/kg, the solvent was acceptable for reuse
at other contaminated sites.
The operating conditions during the SITE demonstration
were documented to identify general operational
procedures. The only significant operational problem
identified during the demonstration was the presence of
residual solvent in treated soil following vacuum
extraction and biological treatment. Although the
concentration of contaminants in the residual solvent at
this site was considered acceptable, it may be a concern at
other sites since the presence of certain organic
contaminants could cause additional handling problems
and regulatory restrictions for managing treated soil.
Information obtained from the SITE demonstration was
used to conduct an economic analysis to estimate treatment
costs for the Terra-Kleen technology. The economic
analysis is based on theoretical sites containing 500,2,000,
and 10,000 cubic yards of PCB-contaminated soil. The
economic analysis yielded costs of $300, $210, and $ 170 per
ton to treat 500, 2,000, and 10,000 cubic yards of soil,
respectively. This unit cost includes the costs of
remediation, site preparation, residuals shipping, handling,
and disposal.
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Section 1
Introduction
This section provides background information about EPA's
Superfund Innovative Technology Evaluation (SITE)
Program, discusses the purpose of the Innovative
Technology Evaluation Report (ITER), and describes the
solvent extraction technology developed by Terra-Kleen
Response Group, Inc. (Terra-Kleen). Additional
information about the SITE Program, the Terra-Kleen
technology, and the demonstration site is available from the
key contacts listed in Section 1.4.
1.1 Brief Description of SITE Program
and Reports
The SITE Program is a formal program established by
EPA's Office of Research and Development (ORD) and
Solid Waste and Emergency Response (OSWER) in
response to the Superfund Amendments and Reauthorization
Act of 1986 (SARA). The SITE Program promotes the
development, demonstration, and implementation of new or
innovative technologies to clean up Superfund sites across
the country.
The primary purpose of the SITE Program is to maximize
the use of alternatives in remediating hazardous waste sites
by encouraging the development and demonstration of new
or innovative treatment and monitoring technologies. The
SITE Program consists of the following four programs: the
Emerging Technology Program, the Demonstration
Program, the Monitoring and Measurement Technologies
Program, and the Technology Transfer Program.
The Emerging Technology Program
The Emerging Technology Program involves pilot or
laboratory testing of successfully proven, bench-scale
technologies that are in the early stage of development.
Successful technologies are encouraged to advance to the
Demonstration Program.
The Demonstration Program
The objective of the SITE Demonstration Program is to
develop reliable performance and cost data on innovative
technologies so that potential users may assess the
technology's site-specific applicability. Technologies
evaluated are either currently available or nearly available
for remediation of Superfund sites. SITE demonstrations
are conducted on hazardous waste sites under conditions
that closely simulate full-scale remediation conditions, thus
ensuring the usefulness and reliability of the information that
is collected. Data collected are used to assess the
performance of the technology, the potential need for pre-
and posttreatment waste processing, potential operating
problems, and the approximate costs. The demonstrations
also enable evaluation of long-term risks and operating and
maintenance costs.
Technologies for the SITE Demonstration Program are
selected through annual requests for proposals and
invitations to successful innovative technology developers.
The ORD staff reviews the proposals to determine which
technologies show the most promise for use at Superfund
sites. Technologies chosen must be at pilot- or full-scale
stage, must be innovative, and must have some advantage
over existing technologies. Mobile technologies are of
particular interest.
After EPA has accepted a proposal, cooperative
agreements between EPA and the developer establish
responsibilities for conducting the demonstrations and
evaluating the technology. The developer is responsible for
demonstrating the technology at the selected site and is
expected to pay costs for transporting, operating, and
removing the equipment. EPA is responsible for project
planning, sampling and analysis, quality assurance and
quality control, preparing reports, disseminating information,
and transporting and disposing of treated waste material.
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The Monitoring and Measurement
Technologies Program
Existing technologies that improve field monitoring and site
characterizations are identified in the Monitoring and
Measurement Technologies Program. This program
supports new technologies that provide faster, more cost-
effective contamination and site assessment data. The
Monitoring and Measurement Technologies Program also
formulates the protocols and standard operating procedures
for demonstrating methods and equipment.
The Technology Transfer Program
The Technology Transfer Program disseminates technical
information on innovative technologies through various
activities in the Emerging Technology, Demonstration, and
Monitoring and Measurements Technologies Programs.
These activities increase the awareness and promote the use
of innovative technologies for assessment and remediation
at Superfund sites. The goal of technology transfer activities
is to develop communication among individuals who require
up-to-date technical information.
The results of the Terra-Kleen technology demonstration
are published in two documents: the SITE Technology
Capsule and the ITER. The SITE Technology Capsule
provides relevant information on the technology,
emphasizing key features of the results of the SITE
demonstration. Both the SITE Technology Capsule and the
ITER are intended to be used by individuals making a
detailed evaluation of the technology for a specific site and
waste.
1.2 Innovative Technology Evaluation
Report
An ITER provides information on a technology
demonstrated under the SITE Program, and includes a
comprehensive description of the demonstration and its
results. The ITER is intended for use by EPA project
managers, contractors, and other decision-makers for
implementing specific remedial actions. The ITER is
designed to aid decision-makers in evaluating specific
technologies for further consideration as an applicable option
in a particular cleanup operation and includes information on
cost and site-specific characteristics, and also discusses
advantages, disadvantages, and limitations of the
technology. This report serves as a critical step in the
development and commercialization of a treatment
technology.
Each SITE demonstration evaluates the performance of a
technology in treating a specific material. The
characteristics of other materials may differ from the
characteristics of the treated material. Therefore, a
successful field demonstration of a technology at one site
does not necessarily ensure that it will apply to other sites.
Data from the field demonstration may require extrapolation
for estimating the operating ranges in which the technology
will perform satisfactorily. Only limited conclusions can be
drawn from a single field demonstration.
1.3 Technology Description
The Terra-Kleen solvent extraction (Terra-Kleen)
technology was developed to treat soils contaminated with
polychlorinated biphenyls (PCB) and other organic
constituents. The technology uses a proprietary extraction
solvent at ambient temperatures to transfer organic
contaminants from soil to a liquid phase. The organic-laden
solvent is then filtered and passed through a proprietary
purification unit to remove the organic contaminants from
the solvent. The regenerated solvent is continuously
recycled through the contaminated soil until a desired
cleanup level is attained. Organic constituents concentrated
in the solvent purification unit are disposed of offsite.
The Terra-Kleen proprietary extraction solvent is water
soluble, and is nonchlorinated. The solvent is not considered
a hazardous constituent under the Resource Conservation
and Recovery Act (RCRA) or a hazardous substance under
the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA). Contaminants are mobilized
by the solvent, separating them from the soil: no compounds
are created or destroyed during treatment.
A schematic diagram of the Terra-Kleen technology used
for the SITE demonstration is shown in Figure 1-1. The
major components of the Terra-Kleen technology consist of
the following:
• Solvent extraction tanks (Tanks A, B, C, D, and
E). The solvent extraction tanks contain the soil
throughout the treatment process. The tanks are
manufactured from polyethylene or steel and vary
in size depending on the amount of soil being
treated. A polyethylene or canvas tarp covers the
top of the solvent extraction tanks to contain any
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1 TON
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UNIT PURIFICATION
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STORAGE TANK
Figure 1-1. Schematic diagram of the Terra-Kleen technology.
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organic compounds volatilized during treatment
and to keep out moisture.
• Sedimentation tank. The sedimentation tank re-
moves suspended solids from the extracted solvent.
The tank is manufactured from polyethylene or steel
and varies in size depending on the amount of sus-
pended solids expected in the extracted solvent.
• Microfiltration unit. The microfiltration unit re-
moves small particulates from the extracted sol-
vent. The unit is manufactured from steel and pre-
vents solids from entering the solvent purification
unit.
• Solvent purification unit. The solvent purifica-
tion unit concentrates all organic soil constituents
that have been extracted from the contaminated soil
and yields a purified solvent suitable for recycle.
The solvent purification unit is considered propri-
etary by the developer.
• Clean solvent storage tank. The clean solvent
tank stores the purified solvent once it passes
through the solvent purification unit. The tank is
manufactured from polyethylene or steel and var-
ies in size depending on the volume of solvent re-
quired for treatment.
• Vacuum extraction system. The vacuum unit re-
moves the majority of the residual solvent from the
soil following solvent extraction. The unit varies
in size depending on the volume of soil being
treated and the target level and time required to
reduce residual solvent concentration in the treated
soil.
The Terra-KJeen technology uses four steps in the
treatment process: soil dewatering, soil treatment, solvent
purification, and residual solvent removal. Each of these
steps is described below.
1.3.1 Soil Dewatering
When processing exceptionally wet soils (those with a
moisture content of about 15 percent or greater), the soil is
dcwatered before treatment. Typically, the feed soil is
placed on plastic sheeting and dewatered through the
natural processes of drainage and evaporation. When
treating large quantities of soil with this procedure, the
addition of a vapor collection system and a vacuum pump is
necessary. The water drained off of this soil is collected in
a moisture trap and passed through a carbon filter to remove
remaining particulates and contaminants before being
stored in a water tank for later utilization during final
residual solvent removal. The excess volatile organic
compounds (VOC) and water vapor which result from the
evaporation process are drawn through an activated carbon
filter before discharged to air.
Moisture content may be further reduced by using a
vacuum to draw air through untreated stockpiled soil prior
to placing the soil on plastic sheeting. Dewatering
continues until Terra-Kleen determines that the soil is
suitable for processing. Soil dewatering was not necessary
during the SITE demonstration of the Terra-Kleen
technology since soil at the demonstration site contained
less than 2 percent moisture; therefore, the effectiveness of
the system to reduce soil moisture was not evaluated.
1.3.2 Soil Treatment
Soil is treated in the solvent extraction tanks. For the pilot-
scale SITE demonstration, five polyethylene tanks
measuring 4 feet by 4 feet and 4 feet deep were used as
solvent extraction tanks. When operating a full-scale
technology, soil is typically treated in several plastic-lined
roll-off containers that measure 22 feet by 8 feet and hold
about 20 cubic yards of soil. After the soil is transferred to
the tanks, solvent is pumped from the clean solvent storage
tank into the top of each solvent extraction tank. The
solvent extraction tanks are then covered and sealed to
eliminate contaminant and solvent loss during the
extraction process. Once in contact with the soil, the
solvent mobilizes the soil contaminants. For the SITE
demonstration, each extraction required about 100 gallons
(380 liters) of solvent per tank which remained in contact
with the soil for about 30 to 45 minutes. The organic-laden
solvent (extracted solvent) is then drained from the solvent
extraction tanks.
7.3.3 Solvent Regeneration
The solvent regeneration process is designed to remove
extracted organic contaminants and solid particles from the
solvent. This step generally consists of three unit operations:
sedimentation, filtration, and contaminant removal. The
sedimentation tank removes suspended solids from the
extracted solvent, which is then pumped through the
microfiltration unit to remove small particulates before it
enters a proprietary solvent purification unit, where PCBs
and other organic contaminants are removed. According to
Terra-Kleen, should excess water remain following an
incomplete dewatering procedure (resulting in a soil
moisture content greater than 15%), dilution of the
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recovered solvent could occur and result in the use of
additional solvent extraction cycles to reduce contaminant
concentrations to below site-specific clean up levels. The
extraction efficiency of diluted solvent was not evaluated
since the demonstration untreated soil only contained a
moisture content of 0.83 percent (mass of water relative to
soil mass).
When treating medium- to large-grained sands, Jhe
sedimentation operation is not used because these particles
are not carried out of the solvent extraction tanks in large
concentrations. In such cases, solvent is pumped directly
into the microfiltration unit before entering the solvent
purification unit. During the SITE demonstration, Terra-
Kleen eliminated the sedimentation step, and used the
sedimentation tank to control the flow of solvent through the
microfiltration and solvent purification unit. However,
should the sedimentation step be necessary, the solids which
collected at the bottom of the tank could be disposed of off-
site at a RCRA approved facility using standard
maintenance and disposal procedures.
Following regeneration, the solvent is pumped into the
clean solvent storage tank, where it is stored before reuse in
the next extraction cycle. Terra-Kleen bases the number of
extraction cycles for a given soil volume on the physical
properties and contaminant concentrations of the untreated
soils. Extraction cycles are repeated until the contaminant
concentrations in the soil within the solvent extraction tank
are less than the site-specific cleanup level, as measured by
an on-site GC unit.
1.3.4 Residual Solvent Removal
Following treatment, residual solvent is removed from soil
using vacuum extraction and biological treatment. The
majority of the residual solvent is removed by vacuum; air is
drawn through the soil from air lines connected to the bottom
of the solvent extraction tanks. The solvent vapor and air
drawn from the treated soil passes through a condenser. The
condenser transfers the solvent vapor into a liquid phase and
air emissions are bubbled through a water scrubber to
remove any residual solvent. The solvent is pumped through
the solvent purification unit to remove organic contaminants;
the clean solvent is then pumped to the clean solvent storage
tank (Figure 1-1).
Following vapor extraction, an active biological culture is
introduced to the treated soil in each of the solvent
extraction tanks, initiating biodegradation of any
remaining solvent. Biological treatment removes residual
solvent to trace levels. Current modifications to the Terra-
Kleen vacuum extraction equipment incorporate a larger
blower, conventional refrigeration unit, and a noncontact
heat exchanger to (1) improve solvent vapor recovery, (2)
increase the removal efficiency of the residual solvent in
treated soil, (3) reduce vacuum extraction operating time,
and (4) eliminate solvent vapor emissions.
1.4 Key Contacts
The following sources can provide additional information on
the SITE Program, the technology, and the demonstration
site. Mr. Mark Meckes, the U.S. EPA SITE Project
manager, also can be contacted concerning questions on
QA/QC procedures.
The SITE Program
Annette Gatchett - SITE Program Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7697
Mark C. Meckes - SITE Project Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7348
Terra-Kleen Response Group, Inc.
Alan Cash - President
Terra-Kleen Response Group, Inc.
PO Box 2054
Del Mar, CA 92014
619-558-8762
E-Mail acash@ix.netcom.com
Naval Air Station North Island
Ken Mitchell -Public Affairs Officer
Naval Air Station North Island
Building 605
San Diego, CA 92135
619-545-8167
Information on the SITE Program is also available through
the Cleanup Information Bulletin Board System by calling
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the system operator at 301-589-8368 or through a modem
at 301-589-8366.
A limited number of technical reports are available by
writing the Center for Environmental Research Information,
at 26 West Martin Luther King Drive, Cincinnati, Ohio
45268, or by calling 800-490-9198.
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Section 2
Technology Applicability
This section of the ITER addresses the general applicability
of the Terra-Kleen technology to contaminated waste sites.
Information presented in this section is intended to assist
decision-makers in screening specific technologies for a
particular cleanup situation. The section presents the
advantages, disadvantages, and limitations of the technology
and discusses factors that have a major impact on the
performance and cost of the technology. The analysis is
based primarily on the results of the SITE demonstration at
NASNI and is supplemented by information from the SITE
treatability study and a full-scale remediation.
2.1 Technology Performance
Compared to National
Contingency Plan Evaluation
Criteria
Table 2-1 compares performance of the Terra-Kleen
technology with the National Contingency Plan (NCP)
evaluation criteria found in Title 40 of the Code of Federal
Regulations (40 CFR), Part 300. The following subsections
discuss these criteria.
2.1.1 Overall Protection of Human
Health and the Environment
Based on the results of the SITE demonstration and
subsequent full-scale operations, the Terra-Kleen technology
is capable of reducing concentrations of PCBs, oil and
grease, furans, and chlorinated pesticides in contaminated
soils. Based on the results of the pre- and posttreatment
sampling and analysis during the SITE demonstration, the
Terra-Kleen technology was able to reduce the
concentration of PCBs in contaminated soils by 98.8 ±0.1
percent, and the treated soils met the Toxic Substance
Control Act (TSCA) incineration equivalency concentration
for PCBs in soil of 2 milligrams per kilogram (mg/kg). In
addition, the technology reduced the concentrations of
hexachlorodibenzofuran (HxCDF) by 92 ± 0.82 percent and
pentachlorodibenzofuran (PeCDF) by
76 + 5.28 percent. Oil and grease concentrations were
reduced by 66.3 ± 5.47 percent.
Samples collected during full-scale remedial operations of
the Terra-Kleen technology at Naval Communication
Stockton (NCS Stockton) showed that the technology is
capable of removing 99 percent of the pesticides 4,4'-
Dichlorodiphenyldichloroethane (DDD), 4,4'-
Dichlorodiphenyldichloroethene (DDE), and 4,4'-
Dichlorodiphenyltrichloroethane (DDT) in soils with up to 15
percent clay particles. Appendix B discusses the results of
the evaluation of this full-scale application of the Terra-
Kleen technology.
Terra-Kleen also claims that comparable removal
efficiencies of 99 percent and greater are obtainable for soil
contaminated with organic constituents, including petroleum
hydrocarbons, chlorinated hydrocarbons, polynuclear
aromatic hydrocarbons (PAH), and dioxins. However,
these constituents were not evaluated during the SITE
demonstration.
Operation of the technology poses no known hazards to the
environment or human health. The technology currently
operates as a closed loop system and has operated at full
scale under a permit from the San Diego Regional Air
Authority, one of the nation's strictest air compliance
districts. Dust controls may be required during excavation
and transfer of arid soils to prevent migration of wind-borne
particulates. Health risks to personnel using the Terra-Kleen
technology can be controlled by using hard hats, steel-toed
boots, overalls, disposable gloves, and safety glasses.
Respiratory protection may be required depending on the
concentration and identity of contaminants in untreated soil,
and is required for personnel working near solvent
feedstocks. According to Terra-Kleen, if primary and
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Table 2-1. NCR Evaluation Criteria for the Terra-Kleen Technology
Criteria
Evaluation
Overall Protection
of Human Health
and the
Environment
Compliance with
Federal ARARs
Long-Term
Effectiveness and
Permanence
Reduction of
Toxldty, Mobility, or
Volume Through
Treatment
Protects human health
and the environment by
eliminating exposure to
contaminants in soil
Requires compliance
with RCRA treatment,
storage, and disposal
regulations of a
hazardous waste
Effectively removes
PCBs, PCDF, and oil and
grease from soil; treated
waste could be handled
as waste material; site
may be suitable for reuse
Significantly reduces the
concentration of PCBs
and other organic
contaminants in soil
Short-Term
Effectiveness
Implemenlability
Cost
Community
Acceptance
State Acceptance
Presents potential short-
term risks to workers and
community including
exposure to noise and
contaminants released to
the air during excavation
and handling
May require pretreatment
of soil for particle size
distribution and moisture
content
$170 to $300 per ton;
this includes the cost of
remediation and
preparing the site
Minimal and manageable
short-term risks to the
public may increase
community acceptance
Provides a permanent
solution to contamination
that is preferable to other
soil remediation
technologies
Prevents further contamination of
groundwater and off-site migration by
removing contaminants from soil
Capable of meeting the TSCA
incineration equivalency
concentration for PCBs of 2 mg/kg
Provides irreversible treatment of
contaminated soil
Reduces the toxicity of the soil by
removing PCBs to acceptable levels
Short-term risks are readily
manageable through common site
health and safety practices
High clay content in soil can cause
additional extraction cycles;
technology is limited by cold or
freezing weather
Significant cost items include
equipment, proprietary solvent, and
residual management
Permanence and long-term
effectiveness of the technology may
increase community acceptance
State regulatory authorities may
require that certain permits be
obtained before implementing the
technology, if conducted as part of a
RCRA corrective action; examples
include a permit to operate a
treatment system, and a permit or
approval to potentially store
Requires measures to protect
workers and community during
excavation, handling, and
treatment of soil
Waste residuals generated at
the conclusion of treatment may
require compliance with ARARs
Involves some residual
treatment or disposal
(purification media and
regenerated solvent)
Reduces PCDFs and oil and
grease in soil
Achieves cleanup objectives in
fairly short amount of time
Equipment is transportable and
is also available through local
vendors; mobilization and
demobilization each take about
1 to 2 weeks
Disposal costs are reduced by
concentrating the PCBs and
other organics in the solvent
purification unit
Use of a solvent that is not
considered a hazardous
substance under CERCLA or a
hazardous constituent under
RCRA may increase
acceptance
The technology received a
TSCA national operating permit
for treating PCB-contaminated
soil
10
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secondary containment of the clean solvent and treatment
solvent extraction tanks fail, the solvent readily biodegrades
into inert components with an estimated environmental half-
life of 2 to 3 days in the presence of water and air.
2.1.2 Compliance With Applicable or
Relevant and Appropriate
Requirements
ARARs for the Terra-Kleen technology may include
requirements under TSCA if the waste contains PCBs.
During the demonstration, the Terra-Kleen technology was
able to treat PCB-contaminated soils from more than 50 mg/
kg (the regulatory threshold under TSCA) to less than the
TSCA incineration equivalency concentration for PCBs in
soil of 2 mg/kg. Based on the results of the demonstration
and other full-scale applications of the technology, EPA's
Office of Pollution Prevention and Toxics (OPPT) issued
Terra-Kleen a nationwide permit to treat PCBs with both the
pilot- and full-scale units.
Other potential ARARs for the Terra-Kleen technology
include hazardous waste regulations under RCRA.
Although the Terra-Kleen technology has not yet been used
to treat RCRA hazardous wastes, the ability of the Terra-
Kleen technology to treat soils contaminated with
chlorinated pesticides was evaluated as part of full-scale
remedial activity at NCS Stockton. The results of this
remediation indicated a 99 percent reduction in DDT, DDD,
and DDE concentrations. These results suggest that other
regulated chlorinated organic contaminants may be
successfully treated by the Terra-Kleen technology.
The Terra-Kleen technology generates process residuals
that must be managed in accordance with applicable
regulations under RCRA and TSCA. Residuals include
solids from the sedimentation tank, spent media from the
purification unit, treated soils, and solvent. The appropriate
disposal method for these residuals will be determined by the
origin, identity, and concentration of their contaminants.
Purification media will contain concentrated organic
substances and contaminants. The media is generally
incinerated, but in some cases can be recycled. For some
applications, the contaminants and organics will be
concentrated in this media which can then be transported
off-site for incineration; when this process is necessary, it
constitutes the highest cost item for the waste residuals.
Solvents regenerated during the technology demonstration
contained less than 0.08 mg/kg of PCB (the method
detection limit). These concentrations exempted the
solvents from being listed as PCB-contaminated, thus
making the solvent available for potential re-use in other
applications. Site-specific decisions and contaminant
concentration will determine whether these solvents are
stored for reuse, recycled, or disposed of as waste.
If treated soils meet all site-specific criteria for on-site
replacement, they can be placed back into the excavation.
When soil contaminants are regulatory mixed wastes, or a
combination of extractable and nonextractable contaminants,
some regulated contaminants may remain in the treated
soils. For these instances, the Terra-Kleen technology
facilitates segregation of waste types and media to optimize
final disposal options.
Some solvent may remain in the treated soils following
treatment and should be considered in deciding the final
disposition of treated soil. The allowable amount of residual
solvent will be determined on a site-by-site basis. Current
modifications to the Terra-Kleen technology enable the
developer to control these residuals more effectively than
was possible during the SITE demonstration at the NASNI
site. The solvent itself is not a hazardous substance under
CERCLA or a hazardous constituent under RCRA. If
disposed of as a waste, however, it does exhibit a RCRA
ignitable hazard characteristic and would be classified
accordingly.
Occupational standards for workers at hazardous waste
sites listed in the Occupational Safety and Health
Administration (OSHA) guidelines (OSHA 1910.420) are
applicable to operators of the Terra-Kleen technology.
Risks to workers during remediation activities include those
from emissions, solvent stocks, and direct contact with
contaminated soils. Risks from solvent emissions and soil
contaminants can usually be addressed through use of an air
purifying respirator. Minimal personal protective equipment
(PPE) for remediation activities with the Terra-Kleen
technology will include a hard hat, steel-toed boots, safety
glasses, and overalls. Additional PPE may be required,
depending on contaminant identity and concentration.
2.1.3 Long-Term Effectiveness and
Permanence
During the demonstration, some solvent residuals and
extracted contaminants in solution remained in the soil after
11
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treatment was complete. Solvent residuals could pose a
problem for some remedial sites, but recent modifications to
the Terra-Kleen vacuum extraction system enable more
effective reduction of solvent residuals.
Based on analysis of treated soils from the demonstration,
the contaminants in the residual solvent were not sufficient
to compromise the remedial goals for PCBs or solvent
residuals. In normal practice, site-specific remedial goals
will determine what residual concentrations are acceptable.
Treatability tests conducted before remediation can
establish which technology configuration and operating
parameters must be established to meet site-specific
requirements.
2.1.4 Reduction in Toxicity, Mobility, or
Volume through Treatment
Because the Terra-Kleen technology is a physical
separation procedure, the change in soil toxicity is
permanent and is generally proportional to the contaminant
concentration remaining at the conclusion of treatment.
Accordingly, since the concentration of PCBs in the soil was
reduced by an average of 98.8 ±0.1 percent, and the
concentrations of HxCDF and PeCDF were reduced by 92
± 0.82 percent and 76 ± 5.28 percent, respectively, a
decrease in toxicity attributable to these substances is
assumed. In general, the Terra-Kleen technology will not
alter the structural or chemical nature of contaminants, or
their toxicity characteristics.
Leachate tests confirmed that the PCB concentrations in the
treated soil were below method detection limits. While not
a definitive test, this result infers that residual PCBs in the
treated soil will not continue to leach following treatment.
Since soil contaminants are often present in association with
a carrier fluid (PCBs in oil, pesticides in petroleum bases),
treatment by solvent extraction should significantly reduce
contaminant mobility resulting from the removal of the
chemical transport media.
Reductions of waste volume achieved by the Terra-Kleen
technology depend on the original concentration and
distribution of the contaminant, natural soil organic content,
and volume of contaminated soil to be treated. The potential
reduction of waste is a ratio between the original volume of
contaminated soil and the waste residuals created by the
Terra-KJeen technology. The predominant waste residual
generated by the technology is spent purification media. The
purification media concentrates all extractable organic soil
constituents, not just the contaminants, that have been
removed from the soil by the solvent. The limited scale of the
SITE demonstration did not enable the solvent purification
unit to optimize its contaminant concentration, but the full-
scale operation at NCS Stockton provides an example of
potential reductions in waste volume. About 1 ton of
purification media was generated during treatment of 400
cubic yards (550 tons) of contaminated soil, yielding a waste
volume reduction of 550:1.
The waste purification media are typically incinerated due to
the high concentration of organic contamination. In some
cases, it is possible to regenerate the purification media
which would increase the waste volume reduction ratio since
the volume of waste residual would not include the media
itself.
2.1.5 Short-Term Effectiveness
The Terra-Kleen technology can take from 3 hours (for
small sites with easily extracted contaminants) to several
days or months to remove contaminants depending on the
characteristics and volume of material to be treated. The
technology can be configured in accordance with site-
specific requirements to optimize time and reduce cost.
The treatment process is a physical separation process that
is irreversible once it is implemented.
The number of extraction cycles and the time required to
treat contaminated soil depends on contaminant
concentrations, moisture content, particle size, natural
organic content, and other chemical contaminants that are
present. The remediation goal for the SITE demonstration
(2 mg/kg of PCBs) was achieved using 11 wash cycles, with
each extraction cycle requiring about 3 hours, conducted
over a period of 7 days. Residual solvent removal through
vacuum extraction and biological treatment continued for an
additional 2 weeks.
The full-scale unit at NCS Stockton required three extraction
cycles, and 3 days to treat one extraction tank (about 20
cubic yards) of soil. Nineteen roll-off tanks were used and
several months were required to complete all the solvent
extraction and vacuum extraction cycles, which resulted in
treating a total of 550 tons of soil. Initially, 1 week was
needed for vacuum extraction of residual solvent from each
solvent extraction tank. With the current technology
modifications, this process is reduced to 3 days, with the
capacity to simultaneously treat three solvent extraction
tanks.
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2.16 Implementability
Assembly and operation of the Terra-Kleen technology
involves the use of general soil handling, construction,
industrial, and monitoring equipment. The extraction tanks
and solvent purification unit can be prefabricated or
assembled on site. The full-scale refrigeration-condenser
unit and the vacuum extraction-heat exchanger are available
through an independent supplier, but can be shipped on
reasonably short notice. No treatment delays occurred
during the demonstration, but the vacuum extraction process
was modified to improve residual solvent removal.
Equipment acquisition caused some delays.
The availability of Terra-Kleen technical staff has not been
a limiting factor for operations, but may change with
increased demand. Terra-Kleen may provide training in the
future for facilities purchasing and operating the Terra-
Kleen technology.
Although the Terra-Kleen technology as demonstrated
achieved the primary demonstration objective, the variables
associated with soils, contaminants, and site restrictions may
yield different results at other sites. Terra-Kleen
recommends conducting treatability studies routinely for
each type of contaminant and soil under consideration for
treatment. Terra-Kleen routinely conducts treatability
studies and limited pilot-scale operations to verify treatment
efficiency before implementing full-scale remediations.
2.1.7 Cost
The cost of implementing the Terra-Kleen technology to
remediate a site with PCB-contaminated soils was
estimated for three different volumes of contaminated soil,
and ranged from $170 per ton to $300 per ton. Section 4.0
presents a comprehensive discussion of the analysis used to
develop these cost estimates.
2.1.8 Community Acceptance
Community acceptance of the Terra-Kleen technology has
been relatively positive because this technology does not
involve combustion processes or placement of wastes on
land. However, community concern was expressed during
the SITE demonstration regarding exposure to mgitive
particulate and VOC emissions during transport, handling,
and treatment of contaminated soil. These exposures can be
reduced through dust emission and soil handling controls.
Fire safety may arise as a public concern. However, fire
prevention codes require the use of spark-proof equipment
and insulated wiring for the Terra-Kleen technology. Due to
the addition of the noncontact heat exchanger to warm
recycled air, temperature warning sensors have been
integrated into the operating system to ensure safe handling
and operation in the presence of flammable solvent and
vapors.
Community environmental groups were invited to comment
on the SITE demonstration during the planning and
implementation of work. Public response was generally
supportive.
2.1.9 State Acceptance
The SITE demonstration was approved by the California
Department of Toxic Substance Control Office of Pollution
Prevention and Technology Development, as well as other
local and regional agencies. Approval of other applications
of the Terra-Kleen technology are contingent upon
approvals required under individual state-approved
programs implementing RCRA, TSCA, and the Clean Air
Act (CAA).
Subsection 2.2 further discusses the ability of the Terra-
Kleen technology ability to meet potential regulatory
requirements under these laws.
2.2 Technology Performance Compared
toARARS
This subsection discusses specific environmental, health and
safety, and other regulations pertinent to the operation of the
Terra-Kleen technology. These regulations include those
governing the storage, treatment, transportation, and
disposal of untreated soils and treatment residuals.
Remedial project managers also have to address state and
local regulatory requirements, which may be more stringent.
ARARs discussed in this subsection include provisions
under the following bodies of legislation:
RCRA
CAA
TSCA
OSHA
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• Hazardous Materials Transportation Act (HMTA)
Table 2-2 identifies and discusses specific federal ARARs
that may apply to the Terra-Kleen technology.
2.2.1 Resource Conservation and
RecoveryAct
Personnel using the Terra-Kleen technology may be subject
to hazardous waste management standards if soils are
hazardous wastes as defined under RCRA. RCRA
management requirements include those for persons who
generate, transport, treat, store, or dispose of hazardous
wastes. Wastes defined as hazardous under RCRA include
characteristic and listed wastes. Personnel using the Terra-
Kleen technology must classify the wastes to determine
whether they are listed or characteristic wastes. Criteria for
identifying characteristic hazardous wastes are included in
40 CFR 261C.
Listed wastes from specific and nonspecific sources, off-
speci fication products, and spill residues are described in 40
CFR 261 D. Facilities that manage hazardous wastes are
required to obtain an EPA identification number. Persons
who generate hazardous waste are subject to regulations for
hazardous waste.
After contaminated soils or sludges have been treated by the
Terra-Kleen technology, the treated soils will normally
remain subject to RCRA hazardous waste or state solid
waste regulations. Most hazardous wastes generated by the
Terra-Kleen technology are subject to the RCRA land
disposal regulations (LDR) under RCRA in 40 CFR 268. For
example, residuals must normally be treated to meet
treatment standards expressed in terms of concentrations in
the waste or in a waste extract (see 40 CFR 286 D).
Applicable RCRA requirements also include the following:
• Manifest requirements if the treated soils are trans-
ported off site (see 40 CFR 262 D, and 263)
• Permits for storing treated soils longer than allow-
able accumulation times (generally 90 days)
• Unit-specific requirements for treatment, storage,
and disposal units (see 40 CFR 264 and 265)
For example, tanks used in the Terra-Kleen technology
may be subject to design and operating standards (such as
secondary containment) in 40 CFR part 265 J.
Nonhazardous wastes generated by the Terra-Kleen
technology must be disposed of in accordance with
applicable state regulations governing solid waste.
2.2.2 Clean Air Act
Emissions from the Terra-Kleen technology include VOCs
and particulate matter. The CAA requires states to
implement a program that requires new sources of air
pollutants to obtain permits. Most states have requirements
to obtain preconstruction and operating permits for sources
of air pollutants. Although the Terra-Kleen technology may
be below minimal permitting thresholds for such permits, it is
necessary to check with the state permitting authority under
which the system is operating.
The CAA also requires that major sources that emit more
than specified thresholds of VOCs, particulate matter, and
other air pollutants submit applications for a Title V permit.
Most states are currently in the process of implementing
Title V permit programs. During the excavation,
transportation, and treatment of soils, fugitive emissions are
possible. State air quality standards may require additional
measures to prevent fugitive emissions.
2.2.3 Toxic Substances Control Act
PCB regulations have been issued under the authority of
Section 6(e) of TSCA. Regulations for PCB treatment and
disposal are listed in 40 CFR 761. Wastes containing PCBs
in concentrations of 50 to 500 parts per million (ppm) may be
disposed of in TSCA-permitted landfills or incinerated at a
TSCA-approved incinerator; wastes containing PCBs in
concentrations greater than 500 ppm must be incinerated.
As a matter of policy, EPA also currently requires that a
facility meet the incinerator equivalency performance
standard of 2 ppm for PCBs in soil to obtain a permit for a
treatment or disposal method other than land filling or
incineration.
PCB spills occurring after May 4,1987 must be addressed
under the PCB Spill Cleanup Policy in 40 CFR 761 G. The
policy applies to spills with PCB concentrations greater than
50 ppm and establishes cleanup protocols for addressing
such releases based on the volume and concentration of the
spilled material.
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Table 2-2. Federal and State ARARs for the Terra-Kleen Technology
Demonstration
Activity
ARAR
Description
Basis
Response
Waste Excavation
Storage before
treatment
Waste treatment
Waste
characterization
Storage after
processing
Transportation for off-
site disposal
Transportation for off-
site disposal
Off-site disposal
Off-site disposal
RCRA 40 CFR part Standards that apply
262 or state equivalent to generators of
hazardous waste
RCRA 40 CFR part
264 or 265 or state
equivalents
RCRA 40 CFR part
264 or 265 or state
equivalents
RCRA 40 CFR part
261 or state equivalent
RCRA 40 CFR part
264 or 265 or state
equivalents
RCRA 40 CFR part
262; HMTA 49 CFR
172
RCRA 40 CFR part
263 or state equivalent
SARA Section
121(d)(3);RCRA40
CFR part 262 or state
equivalent
TSCA40CFRpart
761
Standards that apply
to storage of
hazardous wastes in
tanks
Standards that apply
to or treatment of
hazardous waste
Standards that apply
to waste
characterization
Standards that apply
to storage of
hazardous waste
Manifest, marking,
packaging, labeling,
and placarding
requirements before
transport
Transportation
standard
Requirement for off-
site disposal of
Superfund site wastes
Treatment and
disposal requirements
for PCBs
The soils are
excavated for
treatment and are
therefore subject to
regulation
The waste is stored in
a tank before
processing
Soils are treated in a
tank
Need to determine if
excavated waste,
treated waste, and
residuals are RCRA
hazardous waste
Treated waste will be
stored in tanks before
a decision on final
disposition
If hazardous,
treatment residuals
must be manifested
and managed as
hazardous waste
If hazardous,
treatment residuals
must be manifested
and managed as
hazardous waste
Waste is generated
from a response
action authorized
under SARA
Waste material
contains PCBs in
excess of 50 ppm
Obtain EPA ID
number; prepare
contingency plan and
preparedness and
prevention plan
Inspect tanks daily
and maintain in good
condition; provide
secondary
containment for new
tanks
Inspect tanks daily
and maintain in good
condition; provide
secondary
containment for new
tanks
Use knowledge of
processes that
generate waste or test
waste before disposal
Inspect tanks daily
and maintain in good
condition; provide
secondary
containment for new
tanks
Prepare manifest,
properly mark and
label all containers
Use an EPA-licensed
transporter for off-site
disposal
Dispose of waste at a
RCRA-permitted,
interim status, or
approved recycling
facility if residual
waste is hazardous
Dispose of PCB waste
with concentrations
greater than 50 ppm in
a TSCA-approved
landfill or incinerator
Notes: HMTA - Hazardous Materials Transportation Act
SARA - Superfund Amendment and Reauthorization Act
CFR - Code of Federal Regulations
15
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In March 1996, the EPA Office of Pollution Prevention and
Toxics issued Terra-Kleen a national operating permit for
treating PCBs under the TSCA provisions. Terra-Kleen is
the first technology alternative to incineration or land
filling to obtain this certification.
2.2.4 Occupational Safety and Health
Act
CERCLA remedial actions and RCRA corrective actions
must be performed in accordance with OSHA
requirements detailed in 29 CFR parts 1900 to 1926,
especially 1910.120, which provides for the health and safety
of workers at hazardous waste sites. These regulations
require such workers to undergo 40 hours of health and
safety training before entering a RCRA corrective action or
CERCLA remedial action site. On-site construction
activities at CERCLA response or RCRA corrective action
sites must be performed in accordance with OSHA
regulations at 29 CFR 1926, which provides health and
safety regulations for construction sites. State OSHA
requirements may be more strict than federal standards, and
must be observed when applicable.
For most sites, minimum PPE for technicians operating the
Terra-Kleen technology will include gloves, hard hats, steel-
toed boots, and coveralls. Depending on contaminant types
and concentrations, additional PPE may be required. Noise
levels must be monitored to ensure that workers are not
exposed to noise levels above a time-weighted average of 85
decibels over an 8-hour day. Operation of the Terra-Kleen
technology is not expected to exceed this limit; however,
should the technology or equipment operating in the vicinity
cause noise levels to exceed this limit, workers are required
to wear ear protection.
2.2.5 Hazardous Materials
Transportation Act
If residuals from the Terra-Kleen technology are to be
transported off site, HMTA contains requirements for these
materials while they are in transit. Containers and transport
vehicles may be required to be marked and labeled in
accordance with regulations in 49 CFR 172 C and D,
respectively. Transport vehicles also must be placarded as
specified by regulations in 49 CFR 173 E. In addition, the
shipment must be accompanied by a shipping paper as
specified hi 49 CFR 172 C if the material is not defined as a
RCRA hazardous waste.
2.3 Operability of the Technology
The Terra-Kleen technology equipment mainly consists of
solvent extraction tanks, a sedimentation tank, a
microfiltration unit, a solvent purification unit, a clean solvent
storage tank, and a vacuum extraction system. The entire
system is transportable and can be configured to treat soil
volumes ranging from a few cubic yards to the much larger
volumes typically generated at hazardous waste sites. Pilot-
scale units have been tested with 1-ton and 5-ton treatment
capacities. The full-scale unit has been tested with about 550
tons of soil. Many of the technology components are
available from local vendors throughout the United States.
Once installed and balanced, the Terra-Kleen technology
requires minimal support from on-site personnel. Tasks
involved in operating the Terra-Kleen technology include
assembling equipment, loading and unloading soil, pumping
solvent into the extraction tanks, sampling extraction solvent,
and sampling untreated and treated soil. Two people can
usually assemble the equipment within 2 weeks for both
pilot- and full-scale units if all necessary facilities, utilities,
and supplies are available. Typically, the pilot-scale unit
requires one operator and the full-scale unit requires two
operators to monitor treatment progress.
Since much of the process operates at ambient temperature
and the soils are not moved once they are loaded into the
solvent extraction tanks, mechanical difficulties are limited.
However, the developer performs routine maintenance and
inspection of the Terra-Kleen technology during remediation
activities. Items inspected during routine maintenance
included solvent pumps, hose connections, and fittings.
To ensure that the technology is capable of achieving the
desired remedial goals, treatability tests are recommended
before full-scale remediation. Site-specific cleanup levels,
soil particle size, moisture, and humic content are the primary
determinants for the number of extraction cycles and the
effort required to remediate a specific soil type. For
example, results from the full-scale remediation indicate that
in three solvent extractions, the Terra-Kleen technology
reduced chlorinated pesticides in soil from 80.0 mg/kg to
0.093 mg/kg. By contrast, 57 solvent extractions were
required during the SITE treatability study to reduce PCS
concentrations from 640 mg/kg to 6.0 mg/kg in a soil with
high humic content and 14.5 percent clay and fines.
According to Terra-Kleen, optimal soil conditions for soil
treatment include soil containing less than 15 percent clay
and less than 15 percent moisture content. As a result,
16
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pretreatment of soils may be necessary to reduce clay
aggregate size and moisture content. One pretreatment
option is screening and drying soils using vacuum
extraction. The Terra-Kleen technology does not normally
require screening of large soil particles or objects (large
rocks and debris over 18 inches) before treatment;
however, this material should be removed before treatment
if it poses handling problems during loading and unloading
of soil. Because the Terra-Kleen technology is a batch
process, these materials can still be treated; however, it is
advisable to treat them separately.
2.4 Applicable Wastes
The Terra-Kleen technology used for the SITE
demonstration was designed to remove PCBs from
contaminated soil. The developer claims that the technology
can also remove petroleum hydrocarbons, chlorinated
hydrocarbons, pesticides, PAHs, polychlorinated dibenzo-/>-
dioxins (PCDD), and polychlorinated dibenzo-/?-furan
(PCDF). This report documents that the technology can
effectively remove PCBs, chlorinated pesticides, PCDF,
and oil and grease from contaminated soils. Additionally, the
developer claims that in some cases the Terra-Kleen
technology is capable of removing solvent- soluble metals
from contaminated soil following mixture with extraction
agents.
2.5 Material Handling Requirements
The material handling requirements for the Terra-Kleen
technology include managing spent solvent, treated soil,
spent purification media, and decontamination wastes.
About 1,100 gallons of solvent was used for the SITE
demonstration. Of this original quantity, about 930 gallons of
solvent was recovered at the end of the demonstration. Most
unrecovered solvent remained as soil residuals and in the
bottoms of the solvent extraction tanks and pipelines. During
the SITE demonstration, the concentration of PCBs in the
purified solvent was 0.08 mg/kg. Because this PCB
concentration was below the TSCA incineration
equivalency concentration for PCBs of 2 mg/kg, the residual
solvent from the Terra-Kleen technology was suitable for
reuse, eliminating any disposal costs.
Other residuals include treated soil and spent purification
media. If applicable regulatory restrictions and treatment
goals have been achieved, treated soils can be backfilled on
the site. The environmental half-life of the Terra-Kleen
solvent is estimated to be 2 to 3 days in the presence of air
and water. This can be reduced with land farming and
enhanced biodegradation. The spent purification media will
normally need to be disposed of as hazardous or
nonhazardous waste, depending on the source of the
material that was treated or the concentration of hazardous
constituents in the spent purification media.
Wastes are generated during soil loading, sampling, and
demobilization activities. Typically, the wastes generated by
the Terra-Kleen technology include decontamination water
and plastic used to contain water when decontaminating
excavation equipment. The amount of water required to
decontaminate equipment is discussed in Section 2.6.
2.6 SITE Support Requirements
The site support requirements for the Terra-Kleen SITE
demonstration included space to set up the unit, support
equipment, and utilities. The technology requires an area of
about 300 square feet for small-scale, single solvent
extraction tank configurations for treatability studies, and up
to 40,000 square feet for full-scale remediation. The pilot-
scale SITE demonstration consisted of five 1-ton capacity
solvent extraction tanks, requiring an area of about 4,000
square feet.
Support equipment used for the SITE demonstration
included a laboratory trailer and a health and safety trailer.
The laboratory trailer was used for on-site sample analysis
and storage of equipment, and served as an office for
personnel. Two canopies were also used to protect
equipment from inclement weather. Other equipment used
during the demonstration included a front-end loader to
excavate and homogenize soils, health and safety equipment,
and sampling, analytical, and laboratory equipment.
Utilities required for the operation of the Terra-Kleen
technology include potable water and electricity. Water is
required for decontaminating equipment and personnel,
mixing biological slurries, and laboratory use. During the
demonstration, biological treatment required about 15
gallons of water per solvent extraction tank. In addition,
equipment and personnel decontamination required about 50
gallons of water. Solid decontamination wastes may be
stored in roll-off type debris boxes, and the decontamination
water can be stored in 55-gallon drums. Disposal options
depend on local restrictions and on the presence or absence
of contaminants.
Electricity was needed to operate the Terra-Kleen
technology, the office and laboratory trailer, and the health
17
-------
and safety trailer. The Terra-Kleen technology required
220-volt, three-phase, 120-ampere electrical service.
Additional electrical power (100 amperes at 110/220-volt,
single phase) was needed for the laboratory trailer, the
health and safety trailer, and on-site laboratory and office
equipment. A single 5-horsepower air compressor was
used to power pneumatic pumps used for transferring
solvent through the process.
2.7 Limitations of the Technology
The Terra-Kleen technology removes PCBs, PCDFs, oil
and grease, and chlorinated pesticides from contaminated
soils and prevents further migration of these contaminants.
The technology concentrates these contaminants in the soil
purification unit. The media from this unit must be recycled
or disposed of when exhausted. Although the developer
claims that the technology removes petroleum hydrocarbons,
chlorinated hydrocarbons, PAHs, PCDDs, and solvent-
soluble metals, the technology was not evaluated or testing
failed to yield definitive results for these constituents.
Contaminated soils with greater than 15 percent clays or
fines are difficult to treat because contaminants are strongly
sorbed to the soil particles. The soil particle also have a
tendency to form tight aggregates, which are difficult to
break up thereby preventing efficient solvent penetration
into the contaminated soil. Additional soil handling steps
may be required to treat soils with a clay content greater
than 15 percent.
Soils with a moisture content greater than 15 percent must
be dewatered prior to treatment. Excess water in the soil
dilutes the solvent, reducing contaminant solubilization and
transport efficiency. However, the Terra-Kleen
technology can be equipped with a dewatering unit (Section
1.3.1) to remove excess water accumulating in the solvent.
The technology is designed to operate at ambient outdoor
temperatures above freezing. Colder temperatures reduce
solvent effectiveness. Although current modifications to
the full-scale unit incorporate a closed-loop, heated system,
the solvent extraction vessels are not jacketed; therefore,
operation in extreme cold weather conditions may reduce
treatment efficiency.
18
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3.0 Treatment Effectiveness
This section presents the background, demonstration
procedures, and the results and conclusions used to assess
the effectiveness of the Terra-Kleen technology in
removing PCBs, oil and grease, and PCDFs from
contaminated soils. The Terra-Kleen technology assessment
is based on the activities conducted during the SITE
demonstration atNASNI and additional information from a
SITE treatability study and full-scale remediation.
However, because the results of the SITE demonstration
were collected in accordance with a well-defined QAPP,
conclusions are mainly drawn from the demonstration
results.
The Terra-Kleen technology's capability to remove PCBs
from soil was initially demonstrated during the SITE
treatability study conducted at the developer's testing
facility in Okmulgee, Oklahoma. The results of the
treatability study are presented in Appendix A. To
determine if the technology is capable of removing
chlorinated pesticides from soil, EPA collected additional
soil samples during the full-scale remediation at NCS
Stockton. The results of the sampling from the full-scale
remediation are presented in Appendix B.
3.1 Background
EPA conducted a SITE demonstration of the Terra-Kleen
technology at Site 4 on NASNI, which is located in San
Diego, California (Figures 3-1 and 3-2). A description of the
environmental setting at NASNI and Site 4 are presented in
Sections 3.1.1. through 3.1.4.
3.1.1 NASNI
In October 1993, NASNI Site 4 was selected for the SITE
demonstration of the Terra-Kleen technology. NASNI is
located on about 2,520 acres of land at the north end of the
peninsula that forms San Diego Bay and adjoins the city of
Coronado. NASNI is accessible by land through Coronado
by way of the Bay Bridge or through Imperial Beach by
way of the Silver Strand Highway, State Route 75.
NASNI was officially commissioned in November 1912,
and provides services and material to support the operation
of aviation activities and units. Although most of the
industrial operations began in the 1920s, the generation of
large quantities of hazardous wastes at NASNI did not
begin until the 1940s, during World War II. In the 1940s,
NASNI engaged in a wide variety of operations that
involved the use, storage, and disposal of hazardous
materials. Base operations such as aircraft maintenance
and fuel storage operations generated a variety of
hazardous wastes that, combined with past waste disposal
practices, resulted in contamination of soil and groundwater
at several locations on base.
NASNI is currently conducting environmental investigations
under the Installation Restoration Program (IRP) to locate,
investigate, and remediate hazardous waste sites. The IRP
provides a procedural framework for developing,
implementing, and monitoring response actions at NASNI in
accordance with pertinent federal regulations and
applicable state laws. The IRP has currently identified 12
contaminated areas on NASNI and recommended further
investigation of soils, groundwater, surface water, and bay
and ocean sediments (Southwest Division Naval Facilities
[SWDIV] 1993).
The Navy's initiative to expedite remedial cleanup at these
12 contaminated sites is the Naval Environmental
Leadership Program (NELP). The main objective of
NELP is to demonstrate innovative technologies and
expedite compliance and remediation of contaminated sites.
Successful technologies may be applied to remediate
contaminated sites at other Navy facilities. Within this
framework, the Terra-Kleen technology was selected as an
interim remedial action and was demonstrated at Site 4.
19
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U.S. NAVAL
STATION
NORTH ISLAND -
CORONADO
PACIFIC OCEAN
Figure 3-1. NASNI location map.
-------
Figure 3-2. Site 4 location map.
-------
3.1.2 Site 4
Site 4 (Figure 3-3) is a former public works storage yard,
about 3 acres in size, located towards the southeastern
portion ofNASNI. From 1967 through 1976, miscellaneous
debris including electrical transformers, drums, small
containers, scrap metal, and construction materials were
stored at the site. According to past site investigations, about
52 of the electrical transformers stored in this area contained
PCBs (SWDIV 1993). In 1991, all surface material and
debris were removed from the site.
3.1.3 Geology and Soils
Site 4 is underlain by about 25 feet of artificial fill that is
primarily composed of dredged bay sediments. These bay
sediments consist of silty sands and poorly graded sands that
overlie the Bay Point Formation. The Bay Point Formation
is a poorly consolidated deposit, composed of nonmarine and
marine medium- to large-grained fossiliferous sands
containing shell fragments.
Soils on NASNI consist of marine loamy coarse sand that is
derived from weathering of the Bay Point Formation. This
soil is yellow to dark red-brown in color and contains 15 to
25 percent fines (SWDIV 1993). Three percent of the Site
4 soil has a grain size above 4.75 millimeters (mm) or less
than 0.005 mm. About 72 percent of the soil has a grain size
between 0.425 mm and 0.75 mm. Site 4 soil typically
contains less than 1 percent soil moisture.
Groundwater is present at shallow depths beneath NASNI,
varying from about 25 feet below ground surface (bgs) at the
center of the island to about 4 feet bgs within the vicinity of
Site 4 (SWDIV 1993).
3.1.4 Contamination at Site 4
Soil samples collected as part of a RCRA facility
investigation showed that Site 4 soils contained elevated
levels of PCBs (specifically, Aroclor 1260); inorganic
constituents including arsenic, barium, chromium, and lead;
VOCs including ethylbenzene, toluene, and xylene; and
semivolatile organic compounds (SVOC) including PAHs.
Dioxins and furans including heptachlorodibenzo-/?-dioxin,
octachlorodibenzofuran, and HxCDF were also detected in
Site 4 soils (SWDIV 1993). The detected contaminants and
their maximum and average concentrations are presented in
Table 3-1. Figure 3-4 denotes the area on Site 4 that
contained the highest PCB concentrations. Soil from this
area was excavated and treated during the Terra-Kleen
SITE demonstration.
3.2 Demonstration Objectives and
Approach
The SITE demonstration was designed to address one
primary and five secondary objectives selected for
evaluation of the Terra-Kleen technology. These
objectives were selected to provide users of the Terra-
Kleen technology with the necessary technical information
to assess the applicability of the technology to other
contaminated sites. The following objectives were selected
for the SITE demonstration of the Terra-Kleen technology:
Primary Objective:
• Determine whether Terra-Kleen technology reduces
PCBs in soil to less than the TSCA incineration
equivalent concentration for PCBs in soil of 2 mg/
kg
Secondary Objectives:
• Determine Site 4 soil characteristics that may af-
fect technology performance (moisture content,
particle size distribution, oil and grease content)
(SI)
• Determine if the Terra-Kleen technology removes
VOCs, SVOCs, oil and grease, dioxins, and furans
from soils (S2)
• Determine if, following treatment, the PCB con-
centration in the regenerated solvent is less than
the TSCA incineration equivalent concentration for
PCBs of 2 mg/kg to document that the solvent can
be reused (S3)
• Document the operating conditions of the Terra-
Kleen technology (S4)
• Estimate the capital and operating costs of treating
soils and project additional capital and operating
costs for full-scale operations (S5)
The demonstration objectives were achieved by collecting
samples of untreated and treated soil, and from the
regenerated solvent following treatment. To meet the
demonstration objectives, data were collected and analyzed
22
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GOLF COURSE
Building/Warehouse
Terra-Kleen Process
Demonstration Area
Fence
Former railroad spur
Golf course
SOURCE: Modified from SDNF 1993.
Figure 3-3. NASNI Site 4 demonstration location.
23
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Table 3-1. Maximum and Average Contaminant Concentrations
Contaminant
Maximum Concentration
Average Concentration
Polychlorinated biphenyls
Arsenic
Barium
Chromium
Lead
Ethylbenzene
Toluene
Xylene
2-Methylnaphthalene
Phenanthrene
1,2,4-Trichlorobenzene
Heptachlorodibenzo-p-dioxin
Octachlorodibenzofuran
Heptachlorodibenzofuran
35,000 mg/kg
220 mg/kg
670 mg/kg
150 mg/kg
2,800 mg/kg
1,200/zg/kg
200 /^g/kg
6,600 yug/kg
98.0 mg/kg
50.0 mg/kg
1,300 mg/kg
8.0 /ug/kg
230 yug/kg
230 /^g/kg
3,282 mg/kg
30 mg/kg
140 mg/kg
40 mg/kg
533 mg/kg
604 yug/kg
200 yug/kg
3,323 yug/kg
98 mg/kg
16 mg/kg
1,300 mg/kg
8.0
230 y
230 /ug/kg
Note: All concentrations are presented in dry weight.
24
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RECREATIONAL AREA
(UNDER CONSTRUCTION)
P.W. SALVAGE
YARD
PAVED
(ASPHALT)
PCB CONCENTRATION
35,000. mg/kg
GOLF
COURSE
Fence
Soil Excavation Area
SOURCE: Modifisd from SDNF 1993.
o- so1 so-
SCALE 1* = 80'
Figure 3-4. NASNI Site 4 PCB contamination and excavation area.
25
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using methods and procedures summarized in the
following subsections.
3.3 Sampling and Analytical
Procedures
This section describes the methods and procedures used to
collect and analyze samples for the SITE demonstration of
the Terra-Kleen technology. The field and analytical
methods and procedures used to collect and analyze samples
were conducted in accordance with the Terra-Kleen
demonstration QAPP (PRC 1994a). Analytical methods
included Method 8080A for PCBs (EPA 1992), Method
8240 for VOCs (EPA 1992), Method 3550/8270 for SVOCs
(EPA 1992), Method 8280 for dioxins (EPA 1992), Method
9071 for oil and grease (EPA 1992), Method 2540 G for total
volatile solids (EPA 1983), Method D-0422 for particle size
distribution, and Method D-2216 for moisture content. The
sampling and analytical activities for the SITE
demonstration consisted of (1) demonstration preparation,
(2) sampling and analysis program, and (3) field and
laboratory quality assurance and quality control (QA/QC).
3.3.1 Demonstration Preparation
Prcdemonstration activities consisted of preparing the
demonstration QAPP, site health and safety plan (PRC
1994b), and the site. Site preparation activities at NASNI
Site 4 included identifying the highest PCS concentrations
and excavating, homogenizing, and transferring the
contaminated soil into the five solvent extraction tanks.
The soils containing the highest PCB concentrations were
identified by collecting samples and using an on-site GC to
analyze for Aroclor 1260, the only PCB congener detected
in Site 4 soils. Five tons of PCB-contaminated soil were
excavated from several areas and homogenized. Once the
soil was homogenized, each solvent extraction tank was
loaded with 1 ton of PCB-contaminated soil.
3.3.2 Sampling and Analysis Program
This section describes the sampling and analysis program
and sample frequency for collecting demonstration samples.
The objective of the demonstration design was to collect and
analyze samples of known and acceptable quality to achieve
the objectives stated in Section 3.2.
Sampling locations for the SITE demonstration were
selected based on the configuration of the treatment
technology and project objectives; analytical parameters
were selected based on the soil contaminant (Aroclor 1260)
and the project objectives. To meet the project objectives,
PRC collected soil samples at five locations within the
system and one sample of regenerated solvent from a
location within the system during the SITE demonstration.
Soil sampling locations were identified as S-l and S-2, for
untreated and treated soil, respectively. These samples
were collected from the five solvent extraction tanks labeled
S-1A through S-1E for untreated soil, and S-2A through S-
2E for treated soil. The sample of regenerated solvent was
collected after the last extraction cycle from the clean
solvent storage tank. This sampling location was identified
as S-3. The locations at which samples were collected
during the 7-week demonstration are shown on Figure 3-5.
Soil Samples
Soil samples were collected from the five solvent extraction
tanks. Untreated and treated soil samples were collected in
accordance with the "Field Manual for Grid Sampling of
PCB Spill Sites to Verify Cleanup" (EPA 1986). The
manual was used to determine grid locations and sampling
points within the solvent extraction tanks.
Following grid layout and sampling point identification, a
stainless steel auger was used to collect soil cores at seven
sampling locations. One core was collected from each
sampling location to identify PCB concentrations throughout
the 4-foot deep tank. Once a core was collected, about 1,000
grams of soil was placed in a stainless steel bowl. This
procedure was repeated until all the soil samples from each
of the seven sampling locations were collected. The
samples were composited to ensure homogeneity. Soil from
the composite sample was placed in the appropriate sample
container and preserved appropriately for each sampling
parameter.
Samples collected for VOC analyses were not composited.
VOC samples were grab samples, collected directly from
the soil auger. These samples were immediately placed into
sample containers and sent to the laboratory for
compositing. Sample containers and preservatives for these
samples were specified in the QAPP (PRC 1994a).
Regenerated Solvent Sample
One sample of regenerated solvent (S-3) was collected after
the last extraction cycle from an in-line sampling port located
on the clean solvent storage tank. The sample was analyzed
26
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1TON
UNTREATED
SOIL
1TON
UNTREATED
SOIL
CONTAMINANT-LADEN
SOLVENT
(O
VENT
TO <••"•'
ATMOSPHERE
CONTAMINANT-LADEN
SOLVENT
VACUUM EXTRACTION SYSTEM
LEGEND:
UNTREATED SOIL
WASH SOLVENT
AIR AND SOLVENT VAPOR
S-1A UNTREATED SOIL SAMPLING LOCATION
S-2A TREATED SOIL SAMPLING LOCATION
S-3 REGENERATED SOLVENT SAMPLING LOCATION
SEDIMENTATION TANK
MICROFILTRATION SOLVENT
UNIT PURIFICATION
UNIT
CLEAN SOLVENT
STORAGE TANK
Figure 3-5. Terra-Kleen sampling locations.
-------
for PCBs by the off-site laboratory. Sample containers and
preservatives for this sample were specified in the QAPP
(PRO 1994a).
3.3.3 Quality Assurance and Quality
Control Program
Quality control checks and procedures were an integral part
of the Terra-Kleen demonstration to ensure that the QA
objectives were met. These checks and procedures focused
on collecting representative samples free of external
contamination. Four kinds of QC checks and procedures
were conducted during the demonstration: (1) checks
controlling field activities, such as sample collection and
shipment, and (2) checks controlling laboratory activities,
such as extraction and analysis, (3) data quality, and (4) field
and laboratory audits. A detailed discussion of the QA/QC
program is provided in the TER (PRC 1996).
Field Quality Control Checks
To quantity the quality of field activities such as sample
collection, shipment, and handling, three types of field QC
checks (field blanks, trip blanks, and equipment blanks) were
collected. In general, these QC checks assessed the
representiveness of the samples, and ensured that the
analytical data represent actual site conditions.
Field Blanks
Field blanks were collected to assess the potential for cross
contamination of the samples from airborne dust or other
sources during sample collection. For the VOC field blanks,
three 40-milliliter (mL) VOA vials were filled with analyte-
free ASTM Type II reagent water (reagent water). For the
SVOC field blanks, the laboratory supplied two empty 250-
mL amber containers that were filled in the field with reagent
water. Field blanks were collected near the solvent
extraction tanks during treatment. All field blank samples
were labeled and submitted to the laboratory with the regular
samples.
Trip Blanks
Trip blanks were prepared to document potential cross
contamination attributable to shipping procedures. The
analytical laboratory prepared trip blanks by filling two 40-
mL VOA vials with reagent water. The trip blanks were
transported to the site with the other sample containers,
handled in the same manner as the other samples, and
returned unopened to the laboratory with the sample
shipment. The trip blanks also were labeled with their
preparation dates. Trip blanks were only collected for
aqueous VOC analyses. One trip blank (consisting of two
40-mL VOA vials) was included in every shipment cooler
containing VOC samples.
Equipment Blanks
Equipment blanks were collected before soil samples were
collected to determine whether contamination was
introduced by the sampling equipment. Samples were
collected by rinsing
the sampling equipment with distilled, deionized water and
filling a sample bottle with the rinsate.
All blanks showed low level contamination with acetone and
methylene chloride. Because these compounds were
detected in both treated and untreated samples, and are
considered common laboratory contaminants, their
presence was not considered a result of field contamination.
No other compounds were detected.
Laboratory Quality Control Checks
Laboratory QC checks are designed to determine precision
and accuracy of the analyses, to demonstrate the absence of
interferences and contamination from glassware and
reagents, and to ensure the comparability of data.
Laboratory-based QC checks consisted of method blanks,
matrix spike/matrix spike duplicates (MS/MSD), sample/
sample duplicates (DUP), surrogate spikes, blank spike/
blank spike duplicates, and other checks specified in the
analytical method. The laboratory also performed initial
calibrations and continuing calibration checks according to
the specified analytical methods. The results of the
laboratory's internal QC checks for critical parameters are
summarized on a method-specific basis in the TER (PRC
1996). Field procedures for collecting MS/MSD samples
are briefly discussed below.
The demonstration field team collected MS, MSB, and DUP
samples as specified in the QAPP. For those samples
requiring MS/MSD or MS/DUP analyses, three times the
amount of sample required for routine analysis was collected
in the field. In the laboratory, one (MS/DUP) or two (for
MS/MSD) aliquots of this sample were spiked to allow
determination of percent recoveries and relative percent
differences for the MS compounds.
28
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Data Quality
This section summarizes the data quality for soil samples and
the regenerated solvent sample collected and analyzed
during the Terra-Kleen demonstration. A detailed
presentation of the data quality is provided in the TER (PRC
1996). This data quality assessment was conducted to
incorporate the data validation results into the field QC
results, evaluate the impact of all QC measures on the overall
data quality, and remove all unusable values from the
investigation data set. The results of this assessment were
used to produce the known, defensible information employed
to define the investigation findings and draw conclusions.
The QA objectives for this project were established in the
QAPP (PRC 1994a).
A data validation review was conducted of the analytical
data for soil and the regenerated solvent samples collected
during the demonstration to ensure that all laboratory data
generated and processed were scientifically valid,
defensible, and comparable. Data validation was conducted
using both field QC and laboratory QC analyses. The field
samples included equipment blanks, field blanks, and trip
blanks. Laboratory samples included method blanks,
surrogate recoveries, initial and continuing calibration, MS/
MSDs, and sample/sample duplicates. Analytical results
from these samples were used to calculate the precision,
accuracy, representativeness, comparability, and
completeness of the data.
Summaries of analytical QC data are provided in the TER
(PRC 1996) to facilitate validation and analysis of the data.
In general, all data quality indicators met the QA objectives
specified in the QAPP. This indicates that general data
quality was acceptable and that the sampling data is usable
as reported. All data quality indicators associated with
sampling met all acceptance criteria specified in the QAPP.
Field and Laboratory Audits
EPA conducted internal and external system audits to
evaluate field and laboratory QC procedures.
The audits were conducted before data collection and
analysis. Internal audits were performed by the SITE
contractor and were independent of the sampling team. The
results of EPA's external audits are presented in the TER
(PRC 1996).
3.4 Demonstration Results and
Conclusions
This section presents the results and conclusions from the
SITE demonstration of the Terra-Kleen technology. The
SITE demonstration provides the most extensive Terra-
Kleen performance data to date and serves as the foundation
for conclusions on the technology's effectiveness and
applicability to other cleanups. The demonstration results
have been supplemented by information from the Terra-
Kleen SITE treatability study and the full-scale remediation.
This section presents the results and conclusions of the SITE
demonstration by project objective. The specific primary or
secondary objective is shown at the top of each subsection
and is followed by a discussion of the objective-specific
results.
The primary objective was considered critical for evaluating
the Terra-Kleen technology. Secondary objectives provide
additional information that is useful, but not critical, for
evaluating the Terra-Kleen technology. One primary and
five secondary objectives were selected for the SITE
demonstration of the Terra-Kleen technology. These
objectives are discussed in the following subsection.
3.4.1 Primary Objective
Determine whether the Terra-Kleen technology reduces
PCBs in soil to less than the TSCA incineration
equivalency concentration for PCBs in soil of 2 mg/kg
This objective was measured by collecting five samples of
untreated soil and five samples of treated soil from the
solvent extraction tanks and analyzing the samples for
PCBs. The analytical results and percent reductions for
PCBs in the untreated and treated soil from each solvent
extraction tank are listed in Table 3-2. These results indicate
that the Terra-Kleen technology effectively removed PCBs
from each batch of soil. PCBs were reduced to below 2 mg/
kg (the TSCA incineration equivalency concentration limit)
in all treated soil samples collected from the solvent
extraction tanks. Percent reductions of PCBs averaged
98.8 ±0.1 percent for all soil samples collected from the
solvent extraction tanks.
Statistical analysis of the treated soil results also confirms
that the average PCB concentration (1.71 mg/kg) in the
treated soil was significantly less than 2.0 mg/kg at a 95
percent confidence limit ( =0.05). PCB concentrations in
29
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the treated soil from each extraction tank were also
compared to the average PCB concentration for all five
extraction tanks plus or minus 2 standard deviations (1.71 ±
0.22 mg/kg). The results show that all PCB concentrations
in treated soil were within two standard deviations of the
average value, indicating that the observed variation for
PCB concentrations among the solvent extraction tanks
was within control standards for the SITE demonstration.
For each solvent extraction tank, five grab samples were
collected from five subsampling locations throughout the
tank's depth. The soil from each subsample was transferred
to a stainless-steel container and mixed to create a single
composite sample representing each tank; except for Tank
A, which was designated for a field duplicate. Standard
deviation, therefore, cannot be calculated.
3.4.2 Secondary Objective S1
Determine Site 4 soil characteristics that may affect
technology performance (moisture content, particle size
distribution, oil and grease content)
Moisture content analysis indicated that untreated soil
contained an average moisture content of 0.83 percent, as
measured in each of the five solvent extraction tanks. Terra-
Kleen estimates that untreated soil should contain less than
15 percent moisture content prior to treatment. According
to Terra-Kleen, a soil moisture content greater than 15
percent may dilute the extraction solvent, resulting in
additional extraction cycles to reduce contaminants to site-
specific cleanup levels. The extraction efficiency of diluted
solvent was not evaluated during the SITE demonstration,
since the moisture content of the soil was about 1 percent.
Table 3-3 provides the results of the particle size distribution
analysis, which indicates that untreated soil consisted of an
average of 80 percent sand, 15 percent gravel, and 5 percent
silt and clay. The mean particle size was 0.2 mm which is
considered fine gravel according to the unified soil
classification system (Casagrande 1948). Terra-Kleen
estimates that untreated soil should contain less than 15
percent clay and fines. According to Terra-Kleen, soils
containing greater than 15 percent clay and fines may
require additional solvent extraction cycles to remove
contaminants to site-specific cleanup levels. Since the
particle size did not vary between extraction vessels, the
effect of particle size on extraction efficiency could not be
determined for this demonstration.
Appendix A presents the results from the SITE treatability
study at Okmulgee, Oklahoma, in which soils with 14.5
percent clay and fines (O.075 mm) were treated with the
Terra-Kleen technology. In general, the results of the
treatability study indicate that when treating soils with high
clay fractions, additional extraction cycles may be required
to reduce contaminant concentrations to site-specific
cleanup levels.
Oil and grease analyses indicates that untreated soil at
NASNI Site 4 contained an average concentration of 760
mg/kg of oil and grease. According to Terra-Kleen,
additional extraction cycles may be required to remove
PCBs from soil containing elevated oil and grease
concentrations. The relationship between oil and grease
concentration and solvent extraction efficiency was not
evaluated during the SITE demonstration.
3.4.3 Secondary Objective S2
Determine if the Terra-Kleen technology removes VOCs,
SVOCs, oil and grease, dioxins, and furans from soils
This objective was measured by analyzing untreated and
treated soil from the five solvent extraction tanks for oil and
grease, VOCs, SVOCs, dioxins, and furans. Removal
efficiency for VOCs, SVOCs, and dioxins could not be
calculated since the constituents were below the
established method detection limits. The sampling results
for oil and grease and furans are presented in Tables 3-4 and
3-5, respectively.
Oil and grease analyses indicated that the average
concentration of oil and grease in the untreated soil
averaged 760 mg/kg and in the treated soil samples
averaged 258 mg/kg. The average removal efficiency for
the five solvent extraction tanks was 65.9 ±8.11 percent,
with the greatest reductions observed in samples taken
from extraction tanks C (66.3%) and D (79.3%). These
results show that the Terra-Kleen technology can
effectively and consistently reduce the concentration of oil
and grease in soil.
Furan analysis indicates that only HxCDF and PeCDF were
present in Site 4 soil at average concentrations in the
untreated soil of 0.70 ± 0.06 jog/kg and 0.16 ± 0.03 Mg/kg, and
in the treated soil at 0.05 ± 0.003 fig/kg, and 0.04 ± 0.002 jig/
kg, respectively. The average percent reduction for HxCDF
was 92 ± 0.82 percent and for PeCDF was 76 ± 5.28
percent. These results indicate that the Terra-Kleen
technology effectively removes HxCDF and PeCDF from
soil.
30
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Table 3-2. PCB Aroclor 1260 Analytical Results
Tank TankB TankC TankD TankE
Untreated Soil (mg/kg)
Treated Soil (mg/kg)
Percent Removal
130
1.70
98.7
140
1.54
98.9
134
1.69
98.7
147
1.77
98.8
170
1.85
98.9
Note: All concentrations are presented in dry weight.
Table 3-3. Particle Size Distribution Analytical Results
Tank A TankB TankC TankD TankE
Gravel (>4.7 mm)
Sand (<4.7 mm, >2.0 mm)
Silt (<2.0 mm, >0.07 mm)
Clay (<0.07 mm)
Mean Size (mm)
10.3a
83.0
4.0
2.0
0.2
12.2
81.6
3.3
2.9
0.2
12.0
81.7
4.0
2.3
0.2
6.9
86.6
3.3
3.2
0.2
21.8
72.5
2.5
3.2
0.2
Note:
aAII values are mass distribution per tank (%)
31
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Table 3-4. Oil and Grease Analytical Results
Tank A Tank B Tank C
TankD
TankE
Untreated Soil (mg/kg)
Treated Soil (mg/kg)
Percent Removal (%)
747
310
58.5
Notes: Data were unavailable
for individual tanks.
All concentrations are
Table 3-5. Furan Analytical Results
Untreated Soil (/ug/kg)
HxCDF Total
PeCDF Total
Treated Soil (/^g/kg)
HxCDF Total
PeCDF Total
Percent Removal (%)
HxCDF Total
PeCDF Total
Tank A
0.65
<0.41
0.05
0.04
92
*
720
284
60.6
to calculate
presented in
TankB
0.62
0.14
0.05
0.04
91
71
707
238
66.3
767
159
79.3
860
301
65.0
standard deviations
dry weight.
TankC
0.62
<0.34
0.06
0.04
90
*
TankD
0.84
0.16
0.05
0.04
94
75
TankE
0.70
0.22
0.05
0.04
92
81
Notes:
*Percent removal cannot be determined.
Data were unavailable to calculate standard deviations
for individual tanks.
All concentrations are presented in dry weight.
32
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3.4.4 Secondary Objective S3
Determine if, following treatment, the PCB concentration
in the regenerated solvent is less than the TSCA
incineration equivalent concentration for PCBs of 2 mg/
kg to document that the solvent can be reused
This objective was measured by collecting a sample of
purified solvent from the clean solvent storage tank after the
last extraction cycle and analyzing it for PCBs. Analytical
results indicated that the regenerated solvent sample
contained 0.08 mg/kg of PCBs. Since the PCB
concentration was less than the TSCA incineration
equivalent concentration for PCBs of 2 mg/kg, the solvent
was deemed to be acceptable for reuse at other
contaminated sites.
3.4.5 Secondary Objective S4
Document the operating conditions of the Terra-Kleen
technology
The operating conditions during the demonstration were
documented to identify general operating procedures during
the SITE demonstration. The operating conditions and
procedures used by Terra-Kleen for the SITE
demonstration are presented below.
The first phase of the demonstration consisted of
mobilization activities conducted by Terra-Kleen personnel.
The solvent extraction tanks were connected in parallel to
the solvent supply lines and the vacuum extraction system.
Terra-Kleen personnel then continued assembling the
remainder of the technology components, including the
sedimentation tank, the microfiltration unit, and the clean
solvent storage tank.
One ton of PCB-contaminated soil was placed in each of the
five solvent extraction tanks. The tanks were covered and
solvent was pumped into the solvent extraction tanks. For
the SITE demonstration, the average time required to fill the
solvent extraction tanks was 30 minutes, and Terra-Kleen
allowed the solvent to remain in contact with the soil for
about 30 to 45 minutes.
Solvent that was drained from the solvent extraction tanks
flowed into the sedimentation tank. During the SITE
demonstration, the time required to drain the solvent
extraction tanks was approximately 2 hours. As described
in Section 1.3.3, the sedimentation tank is designed to
remove solids from the solvent exiting the solvent
extraction tanks. However, since no suspended solids were
present in the solvent following the extraction cycle, the
sedimentation tank functioned mainly as a holding tank for
the solvent. It also was used to control the flow of solvent
through the microfiltration unit and the solvent purification
unit.
During the SITE demonstration, Terra-Kleen conducted 11
extraction cycles in 7 days. Following the fifth extraction
cycle, the soil in the solvent extraction tanks was sampled
and analyzed onsite to determine the PCB concentration.
Since the concentration of PCBs was above the target
treatment goal of 2 mg/kg, Terra-Kleen continued additional
extraction cycles. Following the eleventh extraction cycle,
the soil in the solvent extraction tanks were again sampled
and analyzed by the on-site GC. Analytical results indicated
that the PCB concentration in all five solvent extraction
tanks was below 2 mg/kg; therefore, the extraction cycles
were discontinued and treated soil samples were collected
and sent to an off-site laboratory for confirmatory analyses.
Following treatment, vacuum extraction and biological
treatment of the residual solvent in the treated soil continued
for an additional 2 weeks, resulting in an overall decrease of
PCB concentration from an average of 144 mg/kg to less
than 1.71 mg/kg. The pipes leading to the sedimentation tank
were disconnected, and the outlet ports located at the bottom
of the solvent extraction tanks were sealed. Residual solvent
in the soil was removed using a centrifugal blower attached
to the solvent extraction tanks. The vacuum used during the
SITE demonstration was an electric unit that operated
continuously to remove solvent vapor from the treated soil.
The exhaust from the vacuum was vented through a
condenser, which consisted of a steel drum surrounded by
ice. The exhaust from the condenser was then directed to
a second drum containing water, which acted as a wet
scrubber to remove remaining solvent vapors before
discharge to the atmosphere. The condensate was then
pumped through the solvent purification unit and into the
clean solvent storage tank.
Vacuum extraction reduced the residual solvent
concentrations by an average of 39.3 percent during the first
day of operation. Two additional days of vacuum extraction
reduced solvent concentrations by an additional 9 percent,
yielding an overall solvent concentration reduction of 48.3
percent during this process. Vacuum extraction was
discontinued after the third day to comply with the terms of
the demonstration air permit. According to the developer,
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current modifications to the vacuum extraction system
eliminate air emissions; therefore, the unit can operate
until the residual solvent remaining in the treated soil is
reduced to 1 to 2 percent.
Following vacuum extraction, the covers to the solvent
extraction tanks were removed and biological cultures were
added to each vessel to reduce the residual solvent in the
treated soil to trace levels. Biological treatment consisted
of mixing microorganisms with water and spraying the
mixture onto the surface of the treated soil in the solvent
extraction tanks. Terra-Kleen personnel monitored the
solvent reductions daily by collecting treated soil samples
and analyzing for residual solvent concentrations with the
on-site GC. Solvent concentrations decreased during the
first 4 days of treatment, with an overall removal efficiency
of about 60 percent following both vapor extraction and
biotreatment. Terra-Kleen conducted biological treatment
activities for 2 weeks. On average, 38.9 percent of the
solvent was removed during vapor extraction and 72.2
percent of the remaining solvent was removed during
biotreatment.
3.4.6 Secondary Objective S5
Estimate the capital and operating costs of treating soils
and project additional capital and operating costs for full-
scale operations
This objective was achieved by using capital cost
information provided by the developer, measuring
electricity consumption, and estimating labor requirements.
A detailed estimate of the capital and operating costs of
constructing a single treatment unit to remediate soil
contaminated with PCBs is presented in Section 4.0. Costs
were placed in 12 categories applicable to typical cleanup
activities and include fixed and annual variable costs.
Since the required volume of soil treated with the Terra-
Kleen technology is site-specific, costs were estimated for
operating a treatment unit for three soil volumes for
comparison. Given a time period of 7 months, the one-time
capital costs for a treatment unit to remediate 500, 2,000,
and 10,000 cubic yards of soil was estimated to be $300,
$210, and $ 170 per ton, respectively. This unit cost includes
the costs of remediation, site preparation, and residuals
shipping and handling.
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Section 4
Economic Analysis
The purpose of this economic analysis is to estimate costs
for using the Terra-Kleen technology to remediate soil
contaminated with PCBs. This economic analysis is based
on the results of the SITE demonstration at NASNI and
information obtained from the full-scale remediation atNCS
Stockton. A theoretical site containing 2,000 cubic yards of
PCB-contaminated soil is presented as the primary scenario
for the economic analysis. A site containing 2,000 cubic
yards of soil was selected as representative of a medium-
sized remedial scenario. The economic analysis model was
also used to develop cost estimates for treating 500 and
10,000 cubic yards of soil to provide a range of operating
costs for likely scenarios.
4.1 Basis of Economic Analysis
The cost estimates were generated using an economic
model developed by the SITE Program to enable
comparison to similar technologies. The model presents
Terra-Kleen operating costs in 12 categories that are
applicable to typical cleanup activities at Superfund and
RCRA sites (Evans 1990). These 12 categories are:
• Site preparation
• Permitting and regulatory requirements
• Start-up
• Equipment
• Labor
• Consumables and supplies
• Utilities
• Effluent treatment and disposal
4.2
Residual and waste shipping and handling
Analytical services
Maintenance and modifications
Demobilization
Assumptions for the Economic
Analysis
This subsection presents assumptions for the economic
analysis. These assumptions were made primarily to
account for variable site and waste parameters. For this
analysis, it is assumed that 2,000 cubic yards of soil
contaminated with PCBs requires treatment. This
assumption is based on the following:
• The treatment system will consist of nine 20-cu-
bic-yard treatment vessels with a total soil capac-
ity of 150 cubic yards
• Soil will be washed five times as this is the aver-
age number of treatments necessary to achieve the
desired results, depending on soil constituents
• The treatment system will be operated 8 hours per
day, 5 days per week
• The vacuum extraction system will be operated 24
hours per day, 7 days per week
• The soil consists of sand and does not require de-
watering before extraction
Using the above assumptions, a period of 7 months would be
necessary to fully treat 2,000 cubic yards of soil from
mobilization through demobilization.
35
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Other assumptions used for this analysis include the
following:
• The site is being remediated as part of a CERCLA
response action and is located near an urban area
in the Midwest
• The area of contamination has been delineated, and
the soil to be treated has been characterized to have
a density of 1.5 tons per cubic yard and contains
500 mg/kg of PCBs. A treatment goal has been
established to reduce the PCB concentration to 5
mg/kg or below; this goal was selected as repre-
sentative of a cleanup goal that has been used at
several CERCLA response and RCRA corrective
action sites.
• No pretreatment of the feed soil (for example, size
separation) will be required
• Solvent extraction activities will be performed in
ambient conditions at temperatures greater than
35°F to enable normal solvent extraction efficiency
• Residual solvent in treated soils will be sufficiently
removed by vacuum extraction and subsequent bio-
degradation to allow the treated soil to be returned
to the site
• Used solvents remaining after treatment will typi-
cally be incinerated off site at a RCRA facility
• Adequate access roads are available at
the site
• A level area of adequate size is available on which
to place the entire treatment system
• Utility lines such as electricity, water, and telephone
are available onsite
• All equipment necessary for treatment can be rented
locally
• All personnel operating the Terra-Kleen technol-
ogy have health and safety training
* Two operators will be required to monitor system
operations and operate heavy equipment
• Terra-Kleen personnel will operate all process
equipment
• Paved staging areas for untreated and treated soils
will not be needed, because the solvent extraction
tanks can be transported to the excavation and back-
filling area
• Treatment time, estimated to be 28 weeks, is as-
sumed to be the same for all three volumes of soil
4.3 Factors Affecting Costs
The following discussion highlights many of the variables
that can affect treatment costs. The effect of these
variables on costs can be discussed only in general terms,
because quantitative information to support other waste
scenarios has not been developed. For example, although
Terra-Kleen claims that it can treat soils, sludges, and
sediments containing PCBs, chlorinated pesticides,
chlorinated hydrocarbons, and other organic compounds,
only PCB-contaminated soils will be considered for this
economic analysis in accordance with information
generated during the treatability study and the demonstration.
Site-specific factors will affect the labor, consumable, and
supply costs of treating soil with the Terra-Kleen
technology. Soil characteristics, contaminant concentrations,
and treatment goals will affect the necessary draining time
in the solvent extraction tanks and the number of extraction
cycles required to achieve desired cleanup levels. In
general, higher concentrations of contaminants in the soil and
lower treatment goals will require more extraction cycles.
Based on the results of the treatability study (Appendix A),
soil moisture content, clay content, and natural humic content
may affect treatment costs, because these soil
characteristics affect whether the contaminated soil will
require pretreatment before solvent extraction, additional
extraction cycles to achieve complete soil penetration, or
additional solvent recovery steps to remove accumulated
water. According to Terra-Kleen, since the technology is
conducted as a batch process, the cost of performing
additional treatment cycles is negligible. Other site-specific
factors to be considered when estimating the cost of the
Terra-Kleen technology include physical site conditions,
geographical site location, site accessibility, and availability
of utilities.
The Terra-Kleen technology is designed to operate under
ambient weather conditions. Cold temperatures reduce
solvent fluid dynamics; extremely cold weather conditions
36
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can impede extraction efficiency. If extraction activities
must be conducted in cold weather, insulated jackets or
other temperature control measures must be used,
increasing site preparation costs. As an alternative,
treatment can be ceased during cold-weather months,
which will increase startup and demobilization costs
(Sections 4.4.3 and 4.4.12).
Another factor that may affect costs is whether
contaminated solvent must be disposed of or can be reused.
Depending on the concentrations of hazardous substances in
the solvent, it may be transported to another remediation site,
if one is available, for reuse. In these cases, little or no
solvent will require disposal, and fewer disposal costs will be
incurred.
The use of additional solvent extraction tanks can reduce the
amount of time required to complete remedial activities. For
example, multiple solvent extraction tanks could be used in
an area with long periods of cold weather that would
normally preclude efficient use of the Terra-Kleen
technology. This will reduce the time required for treatment,
but will increase equipment-related costs such as
mobilization (a component of site preparation) and
equipment (Sections 4.4.1 and 4.4.4).
Permitting and regulatory compliance costs (Section 4.4.2)
will vary, depending on the types of wastes being treated
and under what authorities the treatment is conducted. In
general, actions conducted as part of a CERCLA response
action will not require permits; however, substantive
requirements of environmental laws must be met. Some
activities, such as those involving RCRA hazardous wastes
or PCB-contammated wastes, will require RCRA Subtitle
C or TSCA permits. Regulatory costs also may increase if
personnel who will operate the system have not received
required training (for example, health and safety training
required under OSHA regulations at 29 CFR1910.120[e]).
4.4 Results of the Economic Analysis
For each of the 12 cost categories, Table 4-1 presents the
costs associated with treating 500,2,000, and 10,000 cubic
yards of soil. Reported amounts are rounded to the nearest
5 dollars and are presented in 1995 dollars. The following
subsections discuss the costs associated with treating 2,000
cubic yards of soil.
4.4.1 Site Preparation Costs
Site preparation costs include those for the treatment area,
mobilization, and electricity connection. Costs of
preparing the treatment area include those for building a
spill containment area. About 3,600 square feet will be
needed to accommodate the Terra-Kleen technology and
support equipment considered in this analysis. It is
assumed that two layers of 10-mil polyethylene plastic will
be used as a liner for the treatment area with sandbags
placed under the liner to form a berm around the perimeter.
Terra-Kleen estimates that the material used to prepare the
treatment area will cost about $500.
Mobilization involves delivering all treatment equipment to
the site, preparing the linings for the treatment tanks, and
connecting the electrical lines. (The costs of the proprietary
solvent are presented in Section 4.4.6, Consumables and
Supplies.) The estimated cost for equipment delivery is
estimated at $4,850. Material associated with lining the nine
extraction tanks is estimated to cost $3,250. Once the
complete technology has been delivered to the site, it is
assumed that electricity can be connected for a cost of about
$4,000.
Site preparation is estimated to require about five 8-hour
days to complete. It is assumed that five Terra-Kleen
personnel will be required to prepare the treatment area and
oversee equipment placement. Based on the assumptions in
this analysis, labor costs for site preparation will be about
$6,560 (Section 4.4.5, Labor).
Total costs for site preparation are estimated to be about
$19,160. This cost is identical for all three scenarios
because, based on the assumptions stated in subsection 4.1,
the amount of required equipment and preparation time are
identical.
4.4.2 Permitting and Regulatory
Requirements
Although some time may be spent working with regulatory
agencies, this analysis assumes that the cost of this line item
is negligible because (1) the Terra-Kleen technology will be
operated at a Superfund site (permits are not required for
these operations), and (2) all Terra-Kleen personnel have
received required health and safety training.
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Table 4-1. Costs Associated with the Terra-Kleen Technology
Cost Categories3
Site Preparation6
Regulatory Compliance
Requirements"
Volume of Soil Treated (cubic yards)"
500 2000 10.000
19,160 19,160 19,160
000
Startupd
Equipment11
Labor"
Consumables and Supplies6
Utilities"
Effluent Treatment and Disposal11
Residual and Waste Shipping
and Handling"
Analytical Services"
Maintenance and Modifications"
Demobilization0
Total Fixed Cost0
Total Variable Costs"
Total Costs
Costs per Ton of Soil Treated
25,120
56,375
45,920
32,250
380
20,000
4,700
9,000
0
11,050
$30,210
$193,745
$223,955
$300
61,120
101,190
183,680
129,000
1,520
80,000
15,000
36,000
0
11,050
$30,210
$607,510
$637,720
$210
253,120
232,320
918,400
645,000
7,630
400,000
43,800
180,000
0
11,050
$30,210
$2,680,270
$2,710,480
$170
Notes:
"Costs are in 1995 dollars.
"One cubic yard equals 1.5 tons.
°Fixed costs
"Variable costs
38
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4.4.3 Startup
Startup costs include assembling treatment equipment and
initial startup activities. This analysis assumes that five
Terra-Kleen personnel will assemble piping and connections
to tanks, test valves, and excavate and stage the first batch
of soil for treatment. Startup is estimated to require 108-
hour days to complete, and will begin immediately following
mobilization activities. Startup costs also include a $ 16-per-
ton royalty fee charged by Terra-Kleen. Total costs for
startup are estimated to be $61,120 for a 2,000-cubic yard
site.
4.4.4 Equipment
Equipment costs include those for capital Terra-Kleen
equipment and rental equipment. All equipment is assumed
to be needed for the duration of the remediation. For this
analysis, the duration will be 7 months, including site
preparation and startup.
Terra-Kleen equipment includes proprietary equipment that
cannot be rented, such as pumps, piping, a compressor, flow
lines, and vacuum extraction equipment. Terra-Kleen
provides this equipment to its clients as part of the price of
performing site remediation for a one-time cost of $27,600,
regardless of the size of the cleanup site. In addition, Terra-
Kleen charges a one-time fee of $15,000 to provide a GC to
perform on-site analytical testing. The total cost of capital
equipment is about $42,600.
Rented equipment includes that for the treatment process
itself and auxiliary equipment. For this analysis, rented
treatment equipment, with monthly rental costs, includes the
following:
• Nine 20-cubic-yard treatment vessels ($250 each
per month)
• Two 20-cubic-yard biological treatment vessels
($250 each per month)
• One 6,000-gallon steel solvent tank ($450 per
month)
• One 10,000-gallon sedimentation tank ($550 per
month)
Total rental costs for treatment equipment are about $3,750
per month.
Rented auxiliary equipment, with monthly rental costs,
includes the following:
• One 8-foot by 20-foot mobile office trailer ($320
per month) for equipment storage
• One front-end and backhoe loader ($2,000 per
month) to excavate and load contaminated soil into
the solvent extraction tanks, and then spread treated
soil
• One roll-off truck ($2,000 per month) to transport
the solvent extraction tanks from the excavation
area to the treatment area and then to the backfill
area
• One power steam cleaner ($100 per month) to de-
contaminate equipment when necessary
• One portable toilet ($200 per month).
Total costs for rented auxiliary equipment will be about
$4,620 per month. The total estimated cost for all equipment
associated with this analysis is $101,190 for a 2,000 cubic-
yard site.
4.4.5 Labor
Terra-Kleen provides the personnel required to operate and
maintain the Terra-Kleen technology. The staff for this
analysis, with hourly wage rates that include overhead and
fringe benefits, consist of the following: two operators ($32
per hour), two assistants ($25 per hour), and one project
manager ($50 per hour). All staff members are assumed to
work 8-hour days, 5 days per week for 28 weeks to complete
the project. The project manager will oversee all operations,
collect samples, and perform miscellaneous administrative
functions.
The total cost of labor for the 7 months required to treat 2,000
cubic yards of soil is about $183,680. Labor requirements,
time, and costs associated with site preparation and setup are
presented under separate sections.
4.4.6 Consumables and Supplies
Consumables and supplies include solvents and solvent
purification media, disposable PPE, fiber drums
for the disposal of PPE, the purification unit, and diesel fuel
for heavy equipment. Due to the proprietary nature of the
39
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materials used in the treatment process, the costs of these
materials are provided as the total sum needed to treat 2,000
cubic yards of soil.
Required materials include (1) extraction solvent, and (2)
proprietary solvent purification media for use in solvent
purification units. Required solvent purification media
includes initial volumes to begin treatment and makeup
volumes during treatment. Total solvent cost for this
analysis is about $42,400. The actual makeup volume for
the solvent purification media depends on the concentration
of organic substances in the contaminated soil. For this
analysis, the total cost of solvent purification materials is
about $80,500. The total cost of proprietary materials is
about $122,900.
Disposable PPE includes Tyvek coveralls, gloves, boots,
and air purifying respirator cartridges. At a minimum,
nondisposable PPE includes steel-toed boots, respirators,
hard hats, and safety glasses. It is assumed that both
operators wear PPE during soil excavation activities and
that they change PPE about once per day. It is also assumed
that the assistants do not need to wear PPE unless they
perform work close to excavated soil. Disposable PPE
costs are estimated to be about $30 per day. Total costs for
disposable PPE are estimated at $4,200.
Drums are needed to containerize disposable PPE. It is
assumed that used PPE will be disposed of in 24-gallon
fiber drums. This analysis assumes that disposable PPE
will fill about 24 fiber drums, yielding a total drum cost of
about $290.
Diesel fuel will be used to power all heavy equipment used
at the site. This analysis assumes that 50 gallons per week
will be required and that heavy equipment will be operated
for the duration of the project. Total diesel fuel use is
estimated at about 1,400 gallons. Diesel fuel is assumed to
cost about $1.15 per gallon, for atotal cost of about $1,610.
Total costs of consumables and supplies are estimated at
$129,000.
4.4.7 Utilities
Utilities used by the Terra-Kleen technology and auxiliary
equipment include electricity and water.
Electricity powers the treatment system pumps and mobile
office trailer. Water is required for mixing
biological slurries for solvent biodegradation.
It is assumed that two 3-horsepower vacuum extraction
pumps will operate 24 hours per day during solvent
extraction activities. For this analysis, one 5-horsepower
fluid pumping system is estimated to operate 4 hours per day.
The mobile office trailer is assumed to be in use 10 hours per
day. For this analysis', total electrical use is estimated at
about 20,600 kilowatt hours (kWh). Electricity is estimated
to cost about $0.07 per kWh, inclusive of use and demand
charges. Total electrical costs are estimated at $1,440.
Based on water use during the technology demonstration,
water use is estimated at 1,500 gallons per solvent extraction
tank. Total water use is estimated at 54,000 gallons. This
analysis assumes that water costs about $1.50 per 1,000
gallons; therefore, total water costs will be about $80.
Total utility costs are estimated at $1,520.
4.4.8 Effluent Treatment and Disposal
The solvent and solvent vapors are the only effluents
produced by the Terra-Kleen technology that require
treatment. The current Terra-Kleen technology is equipped
with a solvent purification unit for solvent regeneration and
a vapor control unit. Spent purification media generated by
these units will require proper off-site disposal due to the
presence of concentrated PCBs. Due to the proprietary
nature of this material, the disposal cost is provided as a total
sum of $80,000.
4.4.9 Residuals and Waste Shipping and
Handling
Residuals produced by the.Terra-Kleen technology that
require off-site disposal are spent solvent and drummed
PPE. For this analysis, it is assumed that treated soils and
sediment accumulated in the sedimentation tank can be
backfilled at the site. If treated soils require off-site disposal,
the costs are an additional $130 per cubic yard, plus
transportation costs.
Used solvent is continuously recovered by the Terra-Kleen
technology. Spent solvents may either be disposed of or
reused at another site. This analysis assumes that about
1,000 gallons of spent solvent remain at the completion of site
remediation activities and that this solvent will be disposed.
This analysis further assumes that the wastes are shipped
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within 100 miles to the nearest RCRA-permitted treatment
facility. Transportation costs are assumed to be about $600.
Disposal costs are estimated at about $350 per drum. Total
costs of proprietary solvent disposal are about $7,200.
Drummed PPE is assumed to be disposed of off site as
nonhazardous waste. This analysis assumes that the drums
are accumulated on site until treatment has been completed,
and are then shipped off site in one load. For this analysis,
disposal of about 24 drums is required. Transportation costs
are about $600, and disposal costs are about $300 per drum.
Total costs of drum disposal are estimated at $7,800.
Total shipping and handling costs for residuals and waste are
estimated at $15,000.
4.4.70
Analytical Services
Analytical costs for this analysis include off-site laboratory
analyses and on-site analyses performed by Terra-Kleen.
The costs of off-site laboratory analyses include sample
analysis, data reduction and tabulation, QA/QC, and
reporting. This economic analysis assumes that one
composite sample of treated soil is collected for PCB
analysis from each solvent extraction tank upon completing
treatment, costing about $200 for each sample. Data
reduction, tabulation, QA/QC, and reporting are estimated
to cost an additional $100 per sample. Total analytical
costs are estimated at about $36,000.
Terra-Kleen provides a GC to conduct on-site analysis. The
cost of this equipment is presented in Section 4.4.4,
Equipment. Terra-Kleen includes labor and other
analytical costs in the cost of providing the remediation
service.
4.4.11 Maintenance and
Modifications
Most of the equipment used for the Terra-Kleen technology
is rented. The costs of maintenance and modifications for
equipment are covered in the cost of the rentals. Costs for
maintaining Terra-Kleen equipment are provided in the cost
of that equipment (Section 4.4.4, Equipment).
4.4.12 Demobilization
Demobilization costs include all labor associated with
shutdown, disassembly, and decontamination of equipment;
site restoration; return of rented equipment; and disposal of
the treatment area liner. It is assumed that demobilization
activities will require five Terra-Kleen personnel working
for about five 8-hour days to complete. For a breakdown of
labor levels and wage rates, see Section 4.4.5, Labor.
Total labor costs for demobilization are $5,000.
This analysis assumes that the return costs of rented
equipment are the same as the drop-off costs. Therefore,
return costs for demobilization equipment are $4,850. The
costs associated with returning Terra-Kleen equipment are
covered in the one-time fee for that equipment, so no
additional demobilization cost is included for this equipment
(Section 4.4.4, Equipment).
Disposal of the treatment area liner is required. This
analysis assumes that the liner is placed in four fiber drums,
and transported and disposed of with the drums of used
PPE. The total cost of about $1,200 includes disposal of
the four drums, but does not include the transportation
fee.Total demobilization costs are estimated at $11,050.
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Section 5
Technology Status
Development of the Terra-Kleen technology has continued
into full-scale remedial operations. In July 1994, a full-scale
unit began treating soils contaminated with chlorinated
pesticides at NCS Stockton, in Stockton California. NCS
Stockton selected Terra-Kleen for full-scale treatment of
550 tons of pesticide-contaminated soil. Appendix ,B
presents the procedures used and the results of this full-scale
remediation.
Terra-Kleen has modified the vacuum extraction system by
installing a refrigeration-condenser unit and adding a
noncontact heat exchanger. The new larger condenser unit
has increased the volume of solvent recovery that is recycled
back to the clean solvent storage tank, resulting in reduced
air emissions. The new heat exchanger allows higher
temperature air to enter the solvent extraction tanks, which
increases extraction efficiency.
Terra-Kleen has increased the treatment capacity of the
technology by adding additional solvent extraction tanks,
and enlarging the solvent purification unit to handle an
increased solvent flow. Customized roll-off extraction
tanks have been designed for easy transport and soil
loading and unloading. Additionally, Terra-Kleen has also
trailer-mounted all support equipment to make it easier to
transport the technology.
Future applications of the Terra-Kleen technology are
scheduled for sites in Alaska using a unique in situ
treatment approach. Other full-scale remediations are
planned for Naval facilities throughout the country. The
SITE Program may conduct additional evaluations of the
Terra-Kleen technology for treating PCBs in mixed low-
level radioactive wastes.
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Section 6
References
Casagrande A. 1948. "Classification and Identification of
Soils" Trans. American Society of Civil Engineers Vol-
ume, 113, Pages 901-991.
Evans, G. 1990. "Estimating Innovative Technology Costs
for the SITE Program." Journal of Air and Waste Man-
agement Association. Volume 40, number 7. Pages
1047-51.
PRC Environmental Management, Inc. (PRC). 1994a. Fi-
nal Demonstration Quality Assurance Project Plan for
the Terra-Kleen Solvent Extraction Process. May.
PRC. 1994b. Final Health and Safety Plan for the Terra-
Kleen System Technology SITE Demonstration at Na-
val Air Station North Island, California. April
PRC. 1996. Final Technology Evaluation Report for the
Terra-Kleen Solvent Extraction Technology. July.
Southwest Division Naval Facilities. 1993. Resource Con-
servation and Recovery Act (RCRA) Facility Investiga-
tion (RFI) Report. Prepared by Jacobs Engineering
Group, Inc. December.
U.S. Environmental Protection Agency (EPA). 1983. "Meth-
ods for the Chemical Analysis of Water and Wastes
(MCAWW)." EPA-600/4-79-020. Environmental Moni-
toring and Support Laboratory, Cincinnati, Ohio. Re-
vised March 1983.
EPA. 1986. "Field Manual for Grid Sampling of PCB Spill
Sites to Verify Cleanup." EPA-560/5-86-017. Office of
Toxic Substances. May.
EPA. 1990. A Guide on Remedial Actions at Superfund
Sites with PCB Contamination. Publication No. 9335.4-
01FS. Office of Solid Waste and Emergency Response.
August.
EPA. 1992. "Test Methods for Evaluating Solid Waste."
Physical/Chemical Methods, Laboratory Manual, Vol-
umes 1 Athrough 1C, and Field Manual, Volume 2. SW-
846, Third Edition (Revision 0). Office of Solid Waste.
November 1986 and subsequent revisions.
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Appendix A
Terra-Kleen Treatability Study
Terra-Kleen Response Group, Inc. (Terra-Kleen), has
developed a solvent extraction technology (Terra-Kleen) to
treat soils contaminated with PCBs and other organic
constituents. Terra-Kleen demonstrated its technology
during a treatability study conducted by the Superftmd
Innovative Technology Evaluation (SITE) Program in
October 1993 at Terra-Kleen's facility in Okmulgee,
Oklahoma.
The main objective of the treatability study was to
determine the technology's effectiveness in removing
PCBs from soil. Terra-Kleen used the Toxic Substances
Control Act (TSCA) incineration equivalency performance
guidance level for PCBs of 2 milligrams per kilogram (mg/
kg) as a target treatment level. The study was conducted in
accordance with an EPA-approved Level III quality
assurance project plan (QAPP).
In October 1993, the SITE Program obtained 1-ton batches
of PCB-contaminated soil from each of three sites and
shipped the soils to Terra-Kleen in Oklahoma. These soils
were obtained from Sites 4 and 6 at Naval Air Station North
Island (NASNI) in Coronado, California, and from a site in
Anchorage, Alaska. Soils from these three sites were
excavated from areas with the highest reported PCB
concentrations. Analytical results of all soils revealed that
Aroclor 1260 was the only PCB mixture present. The
Anchorage soil was air-dried to reduce moisture content
prior to treatment; the NASNI soils did not require any
pretreatment.
For the treatability study, Terra-Kleen used a small, pilot-
scale treatment system that consisted of a single 1-ton
solvent extraction tank, a microfiltration unit, a
sedimentation tank, a solvent purification station, a solvent
storage tank, a clean solvent storage tank, diaphragm
pumps, an air compressor, and a vacuum extraction unit.
Each batch of soil was treated separately with multiple
extraction cycles. Treatment times lasted from 3 to 11 days
depending on original PCB concentrations and soil
characteristics.
Terra-Kleen began the treatment process by placing a batch
of soil into the solvent extraction tank. About 75 gallons of
clean solvent was pumped from the clean solvent storage
tank into the solvent extraction tank, completely saturating
the soil. After a 1-hour extraction period, the solvent was
drained into the sedimentation tank, pumped through the
microfiltration unit to remove remaining suspended fines,
and pumped to the solvent purification unit, where PCBs
and other organic contaminants were removed so the
solvent could be used in the next extraction cycle.
Extraction cycles were continued until PCB concentrations
were below 4 parts per million (ppm) in the solvent drained
from the solvent extraction tank (solvent effluent), as
measured by enzyme immunoassay (EIA). Residual
solvent vapors were recovered in a 55-gallon water filter
drum.
Composite samples were collected from untreated and
treated soil in the solvent extraction tank according to the
U.S. Environmental Protection Agency (EPA) PCB
sampling protocols and analyzed using gas chromatography.
In addition, EIA test kits were used in the field to monitor
PCB concentrations in soil and solvent effluent throughout
the treatment process. Laboratory gas chromatography
results were used to document the technology's overall
PCB removal efficiency.
As shown in Table A-l, results from treated soil showed
that PCB removal efficiency ranged from 95.3 to 99.1
percent. PCB concentrations in treated soils from both
NASNI sites were reduced to below the target
concentration of 2 mg/kg. More extraction cycles were
required to reduce the concentration of PCB in the soil to 6.0
mg/kg for soils with higher initial PCB concentrations. As
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demonstrated in treatability studies, the Alaskan soil also
contained a higher percentage of fines, clay, and natural
organic material than the NASNI soils, a fact which may
have contributed to the higher number of extraction cycles
needed to reduce the concentration of PCBs in soil to 6.0
mg/kg. Terra-Kleen's experience with different soils
confirms that a soil's physical characteristics can affect the
number of extraction cycles required to achieve site-
specific cleanup levels.
The reduction of PCB concentrations in NASNI soils
below the target level confirmed the feasibility of using the
Terra-Kleen technology in a full SITE demonstration at
NASNI. The findings from the treatability study were
incorporated into the test plan and QAPP for the
demonstration, which was conducted in June 1994.
Table A-1. Treatability Study Analytical Results
NASNI Site 4
NASNI Site 6
Alaska Site
PCBs in untreated soil
(mg/kg)
PCBs in treated soil
(mg/kg)
Percent Removal (%)
Percent clay and fines,
O.075 mm (%)
Percent moisture
content (%)
Number of extraction
cycles
17.0
0.78
95.3
3.5
0.04
12.0
28.0
1.4
95.0
7.9
1.3
24.0
6.0
6.0
99.1
14.5
15.0
57.0
Notes: All concentrations are presented in dry weight.
The soil from each subsample was transferred to a stainless-steel container and
mixed to create a single composite sample; therefore, standard deviation could
not be calculated.
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Appendix B
Terra-Kleen Technology Full-Scale Implementation
In June 1994, Terra-Kleen Response Group, Inc. (Terra-
Kleen), was tasked to conduct a full-scale remediation of
three pesticide-contaminated sites at Naval Communication
Station Stockton in Stockton, California (NCS Stockton).
Conducted under the Comprehensive Long-Term
Environmental Action Navy (CLEAN) program, Terra-
Kleen remediated soils atNCS Stockton sites 5,5G, and 5H,
that were contaminated with the pesticides dichloro-
diphenyldichloro-ethane (DDD), dichlorodiphenyl-
dichloroethene (DDE), and dichlorodiphenyltrichloroethane
(DDT). These sites reportedly contained DDD, DDE, and
DDT at concentrations up to 150 mg/kg, 50 mg/kg, and 600
mg/kg, respectively.
The goal of the remediation was to reduce the
concentrations of each pesticide below 1 mg/kg. This
concentration was based on the threshold limit concentration
for these compounds and was below the EPA Region 9
preliminary remediation goal for DDT in residential soil (1.3
mg/kg).
Prior to the full-scale remediation, Terra-Kleen conducted a
bench-scale treatability study to determine the technology's
suitability for treating the contaminated soils. Three, 4-inch
composited soil samples were collected and treated. Ten
grams of each of these samples underwent approximately 3
extraction cycles during this analytical procedure. Results
showed that DDD, DDE, and DDT concentrations were all
reduced to below 0.23 mg/kg in treated soil.
Based on the success of the bench-scale study, Terra-Kleen
conducted a full-scale remediation on 400 cubic yards (y3)
or 550 tons of soil to reduce the concentration of pesticides
below 1 mg/kg. Soils were excavated, homogenized, and
placed into 20 y3 extraction tanks. The SITE Program
collected composite samples of untreated and treated soil
from the first extraction tank and analyzed the samples
specifically for DDD, DDE, and DDT.
After three extraction cycles, pesticide concentrations in
the first solvent extraction tank were reduced significantly
below the target level concentration of 1 mg/kg. Percent
removals for all three pesticides ranged from 99.4 to 99.9
percent. Analytical results from the first extraction tank are
shown in Table B-l.
Results from the remaining 19 solvent extraction tanks
indicated that treatment in 16 tanks achieved the target
concentration goal. Percent removals in these 16 tanks
ranged from 98.8 to 99.9 percent for all three pesticides.
The soil in the three tanks that did not meet the target goal
exhibited higher moisture content, possibly from rainwater
intrusion. This increase in moisture content was dealt with
by performing a vacuum extraction, followed by an
additional application of the solvent treatment. Terra-Kleen
reported that increased soil moisture will reduce treatment
effectiveness.
The successful treatment of the NCS-Stockton soils has led
the Navy to consider the Terra-Kleen technology at other
sites at NCS-Stockton and at other naval facilities.
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Table B-1. Full-Scale Analytical Results
Untreated Soil
(mg/kg)
Treated Soil
(mg/kg)
Percent Removal (%
ODD
12.2
0.024
99.8
DDE
1.5
0.009
99.4
DDT
80.0
0.093
99.9
Notes: All concentrations are presented in dry weight.
The soil from each subsample was transferred to a stainless-steel container and
mixed to create a single composite sample; therefore, standard deviation could not
be calculated.
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Appendix C
Vendor Claims for the Terra-Kleen Technology
C.1 Acknowledgments
The development of the Terra-Kleen process has had many
supporters from state and federal regulators, leaders in
Congress and the White House, environmental assessment
companies, citizen environmental groups, and industrial
clients. Terra-Kleen wishes to thank these federal and state
agencies, individuals and companies for the support
received. Special thanks go to the US EPA's SITE team and
its subcontractor PRC Environmental Management, Inc.,
which provided third party documentation of the process.
We at Terra-Kleen are pleased that the results of the
demonstration were favorable, and hope that all parties who
have championed this technology development will feel
justified in their support.
C.2 Recent Developments
Based upon the workperformed in the SITE demonstration,
and other demonstrations of the full-scale unit, US EPA has
issued to Terra-Kleen a nationwide permit to commercially
treat soil contaminated with PCBs. At the time of writing,
this is the only permitted non-thermal (incineration)
treatment available for PCBs in soil. Both the pilot system
and full-scale treatment system are permitted under a
nationwide commercial operating permit through the US
EPA as per the Toxic Substances and Control Act (TSCA)
which regulates PCBs. The US EPA has made a written
finding that "the Terra-Kleen solvent is non-toxic." The
components of the solvent blend have been approved in
limited quantities as "food additives for human consumption"
by the US Food and Drug Administration.
As a result of system testing by the US EPA SITE Program
and by the US EPA Chemical Management Division, Office
of Pollution Prevention and Pesticides, EPA has proposed
new regulations concerning PCB cleanup in soil and debris.
New regulations proposed for 40 CFR
761.61 (a)(4)(ii)(A)(4)(I) consisted of the following:
"Bulk PCB remediation waste may be disposed of onsite
using a solvent extraction process where: A non-chlorinated
solvent is used; the solvent extraction process occurs at
ambient temperature; the extraction process is not
exothermic; and no external heat is used for the extraction
process."
This is a direct description of the Terra-Kleen process, and
is an indication of the level of confidence that US EPA has
in this process.
The process has been selected for use by the US Navy
through the Naval Environmental Leadership Program, of
which Terra-Kleen was one of the first successful
technologies demonstrated. The process is recently
patented, and has other patents pending.
Terra-Kleen has currently expanded the pilot-scale
treatment unit into full-scale permitted units. At this writing,
a full-scale unit has been used to process four sites: the Naval
Communication Station Stockton, where 500 tons of silty soil
contaminated with chlorinated pesticides was treated; and
Naval Air Station North Island, where soils from Installation
Restoration Sites 4, 6, and 10 were processed.
Approximately 6,000 tons of PCB-contaminated soil has
been treated as of this writing, and the Navy is extending the
contract to treat an additional 3,000 tons. Deployment at a
remote Alaska site with PCB contamination is also
scheduled, and several other full-scale projects are currently
in negotiation, including two mixed waste sites.
Terra-Kleen has been selected for the Rapid
Commercialization Initiative (RCI) by the sponsoring
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organizations, US Department of Commerce, US
Department of Defense, US Department of Energy, US
Environmental Protection Agency, Southern States Energy
Board, Western Governor's Association, and the State of
California Environmental Protection Agency (CA EPA).
The technologies selected under this competitive program
will be assisted by the supporting agencies in reducing the
barriers that impede market entry of the technology. RCI
will provide assistance in finding appropriate sites for
demonstration and testing, assistance in verification of the
performance and cost of performance of RCI technologies,
and assistance in facilitating and expediting the issuance of
permits.
C.3 System Improvements Since the
SITE Demonstration
Terra-Kleen has worked with the California air boards in
order to develop a tighter system that will virtually eliminate
any air emissions of Terra-Kleen's non-toxic solvent.
Currently patent pending, the system uses a totally closed air
stream to remove the residual solvent from the soil at a rate
much faster than conventional vapor recovery techniques.
At the date of this writing, the new system has been used on
two California sites successfully. Additions suggested by
the air boards to the system also include equipment to reduce
fugitive emissions from Terra-Kleen's solvent storage
vessels.
The improvements to the vapor recovery portion of the
system allow the microbes to thrive on reduced residual
solvent levels. In third party tests, residual solvent levels as
high as 3,000 mg/kg were reduced to less than 100 mg/kg in
4 days. Tests by US EPA indicate the half life of the solvent
in the environment to be 2 days. The regulatory limits for the
Terra-Kleen solvent in soil are not clear- the only reference
Terra-Kleen could find was within RCRA, which limits the
solvent to 240,000 mg/kg in the water portion of the soil.
Other improvements to the system include faster and more
reliable material handling techniques. The full-scale version
uses 20 cubic yard extraction bins which can handle debris
up to 7 feet in length for processing.
Although the system was tested by the SITE team on sandy
soils at North Island, the system can also be used on tighter
soil. Soil fines at the Stockton site ranged from 24% to 60%.
At this site, a chlorinated pesticide, DDT, was reduced from
several hundred mg/kg to less than 1 mg/kg.
The system can be configured to do large sites and small
sites. One great advantage of the system is the high mobility,
which allows remote sites to be processed cost effectively.
In Alaska, for example, use of the Terra-Kleen technology
is cutting clean up costs of remote sites by over 50% as
opposed to dig and haul, even on small sites.
Another great advantage of the Terra-Kleen system is that
it is an excellent system to separate organic contaminants
from low level radioactive wastes, allowing for economic
disposal of mixed wastes. As a low energy system, the
Terra-Kleen process does not mobilize soil fines out of the
extraction vessels, thus leaving the radioactive soil in the
extraction vessels while the organic contaminants are
removed.
C.4 Comments on theResults of the SITE
Demonstration
Initial results after the fifth wash indicate that the PCB
concentrations were approximately 0.5 mg/kg, much less
than the final results of near 2 mg/kg. This was due to
ponding in the bottom of the extraction tanks, which has been
corrected. Soils currently run with the system, including soils
from North Island, now average less than 1 mg/kg.
During the demonstration, a vapor extraction recovery
system was used to remove residual solvent from the soil.
Due to permit exemption requirements from the San Diego
air district, the vapor recovery process could only be run 3
days. This was less than optimal, and resulted in an unusually
high amount of residual solvent in the soil. At this point,
solvent-consuming microbes and nutrients were added to the
soil. Because of residual solvent levels at this point being as
high as 40,000 mg/kg, the performance of the microbes was
not optimized. Regardless, the microbial activity greatly
reduced the solvent concentration in the 10 days that it was
monitored. There appears to be little doubt that microbial
activity will continue until all the solvent is consumed. It is
also somewhat reassuring that solvent levels initially
encountered by the microbes were not high enough to be
toxic to the microbes. It is also important to note that even
with solvent levels as high as 40,000 mg/kg, no PCBs were
able to be mobilized out of the soil using a TCLP leaching
procedure. Rain water or other natural water entering the
soil does not mobilize any PCBs after treatment, even if high
solvent levels are left in the soil.
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Although only 5 tons of soil was treated during the site
demonstration at NASNI, the principles for scale-up were
determined, and were successfully implemented in full scale
at several other sites. The results from full scale operations
are better than from pilot scale, as may be expected after
system improvements.
C.5 System Advantages Over Other
Remedial Options
C.5.1 Conventional Technology Options
Treatment with the Terra-Kleen solvent extraction system
has several advantages over the conventional treatment of
soil contaminated with semi-volatile and non-volatile organic
chemicals. For many of the contaminants that Terra-Kleen
specializes in, the soils can be landfilled at a specially
permitted facility, or can be incinerated at the few permitted
incinerators. EPA has recently "land banned" many
chemicals spilled in soil, so that soils contaminated with these
chemicals can only be disposed of through incineration or an
alternative technology such as Terra-Kleen. The current
price for incineration is as high as $2,300 per cubic yard, not
including the costs for transportation to the incinerator, and
special hazardous waste taxes. (If the soils are
contaminated with chlorinated dioxins, the incineration price
can be as high as $16,000 per ton.) As many of the sites in
Terra-Kleen's specialty may contain 1,000 to 50,000 cubic
yards of contaminated soil, it can be seen that the costs
involved with soil incineration are staggering. Mobile
incineration facilities are typically less expensive, but are
difficult to permit, and have poor community acceptance.
Few people want an incinerator in their back yard. Terra-
Kleen's treatment costs are typically 20% of incineration
costs because only the waste is incinerated, not all the soil
and debris.
Landfilling of the soils, when allowed, is typically in the $300
to S500 per cubic yard range when all costs are included
(transportation, backfill, taxes, profile fees, manifest fees,
tire wash, truck liners, etc.). Many generators of hazardous
waste hesitate to landfill their soils because of the long term
liability that can be associated with landfills. They see the
problem moving from one area to the next area, instead of
climinatingtheproblem. Landfilling's great advantage is that
it is relatively inexpensive (in the short term, anyway). Terra-
Kleen's advantage here is that it is cost competitive with
landfilling on many sites, and yet the collected waste is
destroyed. Additionally, since the technology is mobile, the
problem is taken care of at the site, rather than having large
volumes of contaminated material shipped though the
community.
C.5.2 Alternative Technology Options
In addition to having advantages over conventional
technologies such as incineration and landfilling, the Terra-
Kleen technology has many advantages over alternative
technologies such as bioremediation, soil vapor extraction,
thermal desorption, and soil washing. Bioremediation, for
example, is limited by a variety of conditions. Cold weather
slows the process, lack of nutrients or oxygen slows or stops
the process, selective compounds create more toxic
compounds when biotreated, and bioremediation can not be
used effectively on a variety of chemical compounds.
Bioremediation may take up to 7 years to be implemented
and be effective. Typically, bioremediation is used for
volatile and semi-volatile contaminants such as gasoline, and
can not be used effectively on the chemicals that Terra-
Kleen processes.
Like bioremediation, soil vapor extraction (SVE) is used
principally for volatile and some semi-volatile organic
contaminants. SVE can not process sites contaminated with
non-volatile organic constituents such as chlorinated
pesticides or PCBs.
Thermal desorption works very well for volatile compounds,
moderately well for semi-volatile compounds, and poorly on
non-volatile compounds. As the range of contaminants to be
treated become less volatile, more and more heat is needed
to remove the contaminants from soil. Thermal desorption
systems can treat the contaminants also processed by Terra-
Kleen, but only with very costly equipment. Mobilization
fees to move a thermal desorption system that treats PCBs
may run as high as $1,400,000. Only very large sites can
afford this type of mobilization cost. Terra-Kleen sizes the
treatment unit to the size of the site, rather than using a "one
shoe fits all" approach. In this fashion, smaller sites can be
cleaned cost effectively in addition to larger sites.
Soil washing is similar to solvent extraction, in that they both
use fluids to separate the contaminants from soil. Soil
washing concentrates the contaminants into a specific size
segment of the soil, such as the fines, while solvent extraction
only removes the contaminants themselves. Soil washing
thereby generates more waste that needs to be removed
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from the site. Soil washing also generates large quantities of
waste water, while solvent extraction systems are typically
closed loop systems that clean and reuse the solvent. Solvent
extraction processes can reach much lower target treatment
levels than soil washing.
As can be seen, Terra-Kleen's solvent extraction system
has many advantages over conventional and alternative
treatment technologies for selected contaminant types. The
process is not designed to be a solution for every type of
contamination, but to be a cost effective treatment for
selected contaminate types.
C.6 Types of Sites Best Suited to Terra-
Kleen's Technology
C.6.1 PCBs
Electrical Utility Companies
These companies have electrical transformers that use
PCBs. Although many electric companies have changed out
their transformers, older spill sites are still a problem for
many of the utilities. The utility companies typically do not
want to landfill the contaminated soil as there is a perception
of long-term liability.
Natural Gas Pipeline Companies
PCBs were used in compressor stations along most of the
natural gas pipeline systems. As PCB-contaminated oils and
condensates built up in the lines, they were swept out with
"pigs" to various dumping points. The dumping points and
the surrounding soils now need to be cleaned at all of these
stations.
Industrial Manufacturing
PCBs were used in transformers and capacitors within the
manufacturing areas. Leaks and vandalism of transformers
in older buildings to obtain the copper wiring have left many
buildings and the soils around the buildings contaminated
with PCBs.
Electrical Transformer Repair Facilities
Several companies have specialized in transformer servicing
and repair. During these operations, PCB-contaminated oils
were dumped into pits. These pits and the surrounding soils
now need to be cleaned.
Mixed Waste Sites
Terra-Kleen has the ability to separate PCBs from low level
radioactive wastes. The PCBs and low level radioactive
waste can then be disposed of separately.
Department of Defense Sites
All military bases used substantial numbers of PCB
transformers. Many of the older transformers were stored
in one location, and subsequently began to leak. With the
shutdown of these military bases, all PCB sites must be
cleaned.
Overseas PCB Sites in US Territories, Alaska,
Hawaii
Due to PCB regulations, contaminated soils are currently
shipped to the continental US for disposal. This is very
expensive. Terra-Kleen has equipment specially
constructed for use at remote sites that can be shipped or air-
lifted for a nominal cost. Savings to the client are
approximately 50% over conventional methods.
Superfund Sites
EPA has identified 34,070,000 cubic yards (approximately
50,000,000 tons) of PCB-contaminated soil on National
Priority List (NPL) Superfund sites. In addition to NPL sites,
there are over 2,000 additional sites within Superfund that
have PCBs as the predominant waste.
C.6.2 Chlorinated Pesticides
Pesticide Manufacturing and Mixing Areas
These sites are highly contaminated with chlorinated
pesticides. They usually are several acres in size, with
contamination typically concentrated within 6 feet of the
surface. Many of these sites are Superfund sites.
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Department of Defense Sites
Many military bases routinely stored, mixed, and used large
volumes of chlorinated pesticides such as DDT. Soils
surrounding mixing and storage sites are often contaminated
with these chemicals. As the military bases close, the need
to clean these sites intensifies.
Crop Dusting Airports
Municipal airports which supported crop dusting operations
are contaminated with a variety of chlorinated pesticides.
The crop dusting planes would often dump any excess
pesticide mixture at the end of the runway prior to landing as
a safety precaution. The washout stations where the planes
would be cleaned are also contaminated.
Cattle Dipping Stations
Cattle were often dipped in toxaphene baths to kill parasites.
As more farmland is being converted to development, these
contaminated sites are being identified and need to be
cleaned before the land can be used.
C.6.3 Mixed Wastes
Organic Wastes Mixed with Low-Level Radioactive
Wastes
The Terra-Kleen system is an excellent system to separate
organic contaminants from low level radioactive wastes,
allowing for economic disposal of mixed wastes. As a low
energy system, soil fines are not mobilized out of the
extraction vessels, thus leaving the radioactive soil in the
extraction vessels while the organic contaminants are
removed.
Removing PCBs from low level radioactive waste allows the
PCBs and low level radioactive waste to be sent to separate
disposal facilities. As the Terra-Kleen system is the only
non-thermal, full-scale commercial operating facility to be
permitted to process PCB wastes, regulatory problems
regarding mixed waste disposal can be solved by using this
system.
organic contaminants from soil, as well as semi-volatile and
non-volatile organic contaminants.
C.6.4 Wood Preservatives
Electric and Telephone Utility Companies/ Wood
Products Companies
Creosote and pentachlorophenol have been used to treat
telephone and electric poles. The pole yards where these
poles were treated have been heavily contaminated. These
sites typically cover acres of ground, with the contamination
concentrated in the top 6 feet of soil.
Railroads
Creosote and pentachlorophenol were used extensively to
treat the railroad ties that are used to hold the train tracks.
The yards where these ties were treated are heavily
contaminated.
C.6.5 Miscellaneous Chemicals
Chemical Manufacture and Distribution
Several chemical manufacturing facilities and distribution
facilities are contaminated with a whole sweep of
contaminants. Many are NPL sites within Superfund.
These sites have been extensively studied and litigated, and
are starting remedial activities.
Department of Defense
Military bases that have stored chlorinated herbicides such
as Agent Orange and other chemicals such as nerve gases
need to be cleaned.
Coal Gasification Sites
Many areas where coal gas was manufactured in the early
1900s are contaminated with poly cyclic aromatic
hydrocarbons. These areas are well-suited to treatment
with solvent extraction technology.
Other organic contaminants can be removed from low level
radioactive waste as well. Terra-Kleen employs a patent-
pending, dustless drying system that can separate volatile
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