EPA/540/R-94/528
April 1995
INNOVATIVE TECHNOLOGY EVALUATION REPORT
Radio Frequency Heating, KAI Technologies, Inc.
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Paper
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NOTICE
The information in this document has been funded by the U.S. Environmental Protection Agency
(EPA) under the auspices of the Superfund Innovative Technology Evaluation Program under Contract No.
68-CO-0048 to Science Applications International Corporation. This document has been subjected to EPA'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 Superfund Innovative Technology Evaluation (SITE) Program was authorized in the 1986
Superfund Amendments. The SITE Program is a joint effort between the U.S. Environmental Protection
Agency (EPA) Office of Research and Development (ORD) and Office of Solid Waste and Emergency
Response. The purpose of the program is to enhance the development of hazardous waste treatment
technologies necessary for implementing new cleanup standards that require greater reliance on permanent
remedies. This is accomplished by performing technology demonstrations designed to provide engineering
and economic data on selected technologies.
This project consisted of an evaluation of an in situ radio frequency heating (RFH) technology
developed by KAI Technologies, Inc. (KAI). As a part of this evaluation, a Demonstration Test was
conducted by the 'SITE Program in coordination with research efforts sponsored by the U.S. Air Force
(USAF). During the demonstration, the KAI in situ RFH system was used to heat soil containing organic
contaminants. The goals of the SITE Program study, summarized in this Innovative Technology Evaluation
Report were: 1) to assess the ability of in situ RFH to remove organic contaminants from a contaminated
site at Kelly Air Force Base and 2) to develop capital and operating costs for the technology.
Additional copies of this report may be obtained at no charge from EPA's Center for
Environmental Research Information (CERI), 26 West Martin Luther King Drive, Cincinnati, Ohio, 45268,
(513) 569-7562, using the EPA document number found on the report's front cover. Once this supply is
exhausted, copies can be purchased from the National Technical Information Service, Ravensworth
Building, Springfield, Virginia, 22161, (800) 553-6847. Reference copies will be available in the
Hazardous Waste Collection at EPA libraries. Information regarding the availability of other reports can
be obtained by calling ORD Publications at (513) 569-7562 or the SITE Clearinghouse Hotline at (800)
424-9346. To obtain further information regarding the SITE Program and other projects within the SITE
Program, telephone (513) 569-7696.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
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ABSTRACT
The KAI Technologies radiofrequency heating system was demonstrated at Site S-l at Kelly Air
Force Base in San Antonio, Texas. Site S-l was formerly used for intermediate storage of wastes destined
for reclamation and was contaminated with mixed solvents, carbon cleaning compounds, petroleum
oils and lubricants at depths up to 30 feet. The radiofrequency heating system was to be used to heat the
soil to facilitate the removal of these contaminants via soil vapor extraction. A separate soil vapor
extraction system was used for this demonstration, but was not evaluated as part of this demonstration.
Results of this demonstration indicate that contaminant removal (measured as TRPH) varied
between 29 % and 42 % . Reasons behind the results observed are discussed in this report. A cost analysis
of the use of the technology is also presented.
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TABLE OF CONTENTS
Section Page
Notice ii
Foreword ill
Abstract iv
List of Tables viii
List of Figures viii
Abbreviations ix
Acknowledgments x
Executive Summary xi
1. Introduction 1
1.1 Background 1
1.2 Brief Description of the SITE Program and Reports 2
1.3 Purpose of the ITER 4
1.4 Technology Description • • 4
1.5 Key Contacts 9
2. Technology Applications Analysis 11
2.1 Objectives: Performance Versus ARARs 11
2.1.1 CERCLA 11
2.1.2 RCRA 14
2.1.3 CAA 15
2.1.4 SDWA 15
2.1.5 CWA 16
2.1.6 TSCA 16
2.1.7 OSHA Requirements 17
2.2 Operability of the Technology 18
2.3 Applicable Wastes 19
2.4 Key Features of theKAI RFH Technology 20
2.5 Availability and Transportability of the System 20
2.6 Materials Handling Requirements 21
2.7 Site Support Requirements 21
2.8 Limitations of the Technology 22
2.9 References 23
3. Economic Analysis 24
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TABLE OF CONTENTS (CONTINUED)
Section
3.1 Introduction ................................................. 24
3.2 Basis of Economic Analysis ...................................... 24
3.3 Issues and Assumptions ......................................... 25
3.3.1 Site Preparation ....................................... 27
3.3.2 Permitting and Regulatory ................................ 27
3.3.3 Equipment ........................................... 27
3.3.4 Startup and Fixed ....................................... 29
3.3.5 Operating Costs for Treatment ............................. 30
3.3.6 Supplies ............................................. 31
3.3.7 Consumables .......................................... 31
3.3.8 Effluent Treatment and Disposal ....................... , - - - - 32
3.3.9 Residuals and Waste Shipping, Handling, and Transport ............ 32
3.3.10 Analytical Services ..................................... 32
3.3.11 Facility Modification, Repair, and Replacement .................. 33
3.3.12 Site Demobilization .................................... 33
3.4 Results of Economic Analysis ..................................... 33
3.5 References .................................................. 34
4. Treatment Effectiveness ............................................. 36
4.1 Background ................................................. 36
4.2 Methodology ................................................. 41
4.2.1 Soil ................................................ 41
4.2.2 SVE Vapor Stream ..................................... 46
4.2.3 Soil Vapor .......................................... 46
4.2.4 Groundwater ......................................... 46
4.3 Performance Data ............................................ 47
4.3.1 Soil Samples ......................................... 47
4.3.2 SVE Vapor Stream ...................................... 51
4.3.3 Soil Vapor Gas ....................................... 52
4.3.4 Groundwater Samples ................................... 53
4.3.5 Moisture ............................................ 53
4.4 Contaminant Migration ........................... 53
4.5 Residuals [[[ 56
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TABLE OF CONTENTS (CONTINUED)
Section Page
5. Other Technology Requirements 57
5.1 Environmental Regulation Requirements 57
5.2 Personnel Issues 57
5.3 Community Acceptance 58
5.4 References 59
6. Technology Status • • 60
APPENDIX A: Performance Data 61
APPENDIX B: Case Studies 126
APPENDIX C: Vendor Claims 129
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LIST OF TABLES
Number Page
1 Summary of SVOC Decreases Inside Treatment Zones xiii
2 Evaluation Criteria for the KAI RFH Technology xiv
3 Federal and State ARARs for the KAI RFH Technology 12
4 Treatment Costs for the KAI RFH System Treating 10,940 Tons of Soil with a
95 Percent On-Line Time 34
5 Target VOCs 39
6 Target SVOCs (Acid Extractables) 40
7 Target SVOCs (Base/Neutral Extractables) 40
8 Summary of Number of Samples Analyzed for the KAI RFH Test 45
9 Summary of SVOC Decreases Inside Treatment Zones 49
10 Average Particle Size Distribution (Wet-Sieving Only) 51
11 Radio Frequency RadiationTLVs 59
LIST OF FIGURES
Number Page
1 Diagram of KAI RFH System 6
2 Regional Maps Showing Demonstration Location 37
3 Plan View of Demonstration Site 38
4 Sampling Depths and Locations 42
5 Locations of Groundwater Sample Collection 53
VIM
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ABBREVIATIONS
AC Alternating Current
ACGIH American Conference of Governmental
Industrial Hygienists
AFB Air Force Base
ANGB Air National Guard Base
ARAR Applicable or Relevant and Appropriate
Requirement
ASTM American Society for Testing and Materials
ATTIC Alternative Treatment Technology
Information Center
bgs below ground surface
B&RE Brown & Root Environmental
CAA Clean Air Act
CERCLA Comprehensive Environmental Response,
Compensation, and Liability Act
CERI Center for Environmental Research Information
CFR Code of Federal Regulations
CPR cardiopulmonary resuscitation
CWA Clean Water Act
DOT Department of Transportation
EPA Environmental Protection Agency
FCC Federal Communication Commission
FID flame ionization detector
ITER Innovative Technology Evaluation Report
KAI KAI Technologies, Inc.
LDR Land Disposal Restrictions
MCL Maximum Contaminant Level
MDL Method Detection Limit
MS/MSD Matrix spike/Matrix spike duplicate
NAAQS National Ambient Air Quality Standards
NPDES National Pollutant Discharge
Elimination System
ORD Office of Research and Development
OSC on-scene coordinator
OSHA Occupational Safety and Health
Administration
OSWER Office of Solid Waste and
Emergency Response
PCB polychlorinated biphenyl
PPE personal protective equipment
ppm parts per million
PQL Practical quantitation limit
QA/QC quality assurance/quality control
RCRA Resource Conservation and Recovery Act
RF radio frequency
RFH radio frequency heating
RI/FS remedial investigation/feasibility study
RPM remedial project manager
RREL Risk Reduction Engineering Laboratory
SAIC Science Applications International
Corporation
SARA Superfund Amendments and Reauthorization
Act
SDWA Safe Drinking Water Act
SITE Superfund Innovative Technology Evaluation
SVE Soil vapor extraction
S V O C Semivolatile organic compound
TLV Threshold Limit Value
TRPH Total recoverable petroleum hydrocarbons
TSD Treatment, Storage, and Disposal
TSCA Toxic Substances Control Act
USAF U.S. Air Force
VISITT Vendor Information System for Innovative
Treatment Technologies
v o c Volatile organic compound
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ACKNOWLEDGMENTS
This report was prepared under the direction and coordination of Ms. Laurel Staley, Environmental
Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Work Assignment Manager
in the Risk Reduction Engineering Laboratory (RREL), Cincinnati, Ohio. EPA-RREL contributors and
reviewers for this report were Teri Richardson, Michelle Simon and Robert Stenburg. Other contributors
and reviewers were Raymond Kasevich and Dave Faust of KAI Technologies, Inc. and Victoria Wark,
Paul Carpenter and Lt. Donald Aide of the United States Air Force.
This report was prepared for EPA's SITE Program by the Technology Evaluation Division of
Science Applications International Corporation (SAIC) in Cincinnati, Ohio under Contract No. 68-CO-
0048. This report was written by Sharon Krietemeyer and Eric Saylor. The Work Assignment Manager
for the project was Margaret Groeber.
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EXECUTIVE SUMMARY
This document is an evaluation of the performance of an in situ radio frequency heating (RFH)
system developed by KAI Technologies, Inc. (KAI). This report examines data from the demonstration
concerning the technical and economic aspects of KAI's RFH technology, particularly its ability to
remediate soil contaminated withorganics.
A demonstration of KAI's in situ RFH system was conducted from January 1994 to July 1994 at
Kelly Air Force Base in San Antonio, Texas. This demonstration was conducted as a joint effort of the
U. S . Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE)
Program and the U.S. Air Force (USAF).
EPA conducted pre- and post-treatment soil sampling and analysis. USAF provided the site for
the test; necessary logistical and administrative support; and made arrangements with the technology
developer, KAI, to operate its RFH process during the test.
Both EPA and USAF intend to prepare separate reports on this project. Each report will examine
the data and results of the test in light of its own perspective. This report, prepared by EPA, discusses the
results of the KAI demonstration with respect to the technology's potential Superfund applications.
The technology was never intended to remediate the site during the demonstration. Nevertheless,
within certain limitations, changes in contamination levels within the area treated during the demonstration
can be used to provide a very preliminary indication of how the technology in its present state of
development might perform if used to remediate a site. These limitations include the fact that the
technology is still being developed and may perform differently when used at a future date and at a
different site. In addition, during the demonstration, implementation of the soil vapor extraction (SVE)
system and other factors may have affected the data obtained from the demonstration, making it difficult
to isolate the effect of the RFH on contaminant removal from the soil. These limitations are discussed in
more detail in the report.
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KAI Technologies disagrees with the use of data from the demonstration to predict performance
in an actual remediation. For a more detailed discussion of KAFs perspective on the results of the
demonstration, please see Vendor's Claims in Appendix C
The RFH technology uses electromagnetic energy in the radio frequency (RF) band to heat
contaminated soil in situ, thereby potentially enhancing the performance of standard SVE technologies.
The RF energy volatilizes contaminants and moisture in the soil, and the resulting steam and contaminant
vapors are collected by a standard SVE system.
The demonstration began with initial sampling conducted from January 11, 1994 through January
19, 1994, during the installation of the subsurface system components. RF energy was applied to the soil
from April 24, 1994 through June 7, 1994. The soil was allowed to cool for 1 month, and final sampling
was conducted from July 7, 1994 to July 13, 1994. Based on the sampling data collected before and after
treatment, an evaluation was made concerning the technology's ability to remove total recoverable
petroleum hydrocarbons (TRPH) contamination from soil. This was considered the primary objective of
the demonstration. Because RFH was actually applied only to the upper half of the original treatment zone,
this upper region is designated the "revised treatment zone." A comparison of TRPH concentrations in
the pre- and post-treatment soil samples within these two zones yielded the following results:
Within the original treatment zone there was a statistically significant change in TRPH
concentrations at the 90 percent confidence level. The estimated geometric mean decrease
was 29 percent. Concentrations in the pretreatment samples varied from less than 169 to
105,000 parts per million(ppm); post-treatment samples varied from less than 33 to 53,200
ppm.
Within the revised treatment zone there was a statistically significant change in TRPH
concentrations at the 95 percent confidence level. The estimated geometric mean decrease
was 49 percent. Concentrations in the pretreatment samples varied from less than 169 to
6,910 ppm; post-treatment samples varied from less than 33 to 4,510 ppm.
Outside the original treatment zone there was a statistically significant change in TRPH
concentrations at the 97.5 percent confidence level. The estimated geometric mean increase
was 90 percent. Concentrations in the pretreatment samples varied from less than 171.5 to
43,500 ppm; post-treatment samples varied from 762 to 92,600 ppm.
Outside the revised treatment zone there was a statistically significant change in TRPH
concentrations at the 80 percent confidence level. The estimated geometric mean increase
was 39 percent. Concentrations in the pretreatment samples varied from less than 171.5 to
105,000 ppm; post-treatment samples varied from 184 to 92,600 ppm.
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Contaminant removals did not meet projections. Before the RFH system was turned on, USAF
and KAI made the decision to apply heat to the revised treatment zone. They targeted only volatile
organics, specifically gasoline-range hydrocarbons, as the contaminants of concern, which allowed KAI
to lower the treatment temperature from 150°C to a range of 100 to 130°C. These changes were based on
timing and funding limitations placed on the project by USAF just prior to startup. (No changes in the
Demonstration Plan were made because the SITE Program was not informed about this decision until after
post-treatment sampling was completed.)
A number of problems with the design and operation of the SVE system were identified after the
demonstration was complete. These problems included vapor extraction wells screened below the revised
treatment zone, which may have drawn contaminants into the cooler soil, and SVE system configurations
which may have resulted in slow vapor flows within the revised treatment zone and in high vapor flows
from areas outside the revised treatment zone. These problems may have resulted in contaminant migration
into the original treatment zone from the revised treatment zone and from surrounding soils. In addition,
only a portion of the revised treatment zone appears to have reached the revised target temperature range
of 100 to 130°C, which was at least partly due to a power supply problem unrelated to the operation of the
KAI RFH system.
Because of changes in the RFH system prior to startup and the design of the SVE system, it cannot
be concluded that the changes in TRPH concentration inside and outside the treatment zones were a result
of RFH treatment. The soil data indicate changes in TRPH concentration, but it is not possible to
determine what impact RFH had on contaminant removal rates, with the alternative being using the SVE
system alone.
An economic evaluation was performed based on the original design of the RFH system for the
demonstration. Because of the problems encountered during the demonstration, several assumptions had
to be made about the technology. Even though no conclusions about the success of RFH at this site can
be made, the economic evaluation assumes the technology will meet target cleanup levels within a given
time frame. The results of this evaluation are as follows:
The cost to treat approximately 10,000 tons of contaminated soil using a proposed full-scale
in situ RFH system (including costs associated with SVE) was estimated by scaling up costs
for the original treatment zone. Cleanup costs are estimated to be $336 per ton if the system
is utilized 95 percent of the time. This estimate does not include costs for several site- and
project-specific factors.
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In addition to evaluating changes in TRPH concentrations, evaluations were made concerning the
technology's ability to remove semivolatile organic compounds (SVOCs) and volatile organic compounds
(VOCs) from soil. These were considered secondary objectives of the demonstration.
A comparison of SVOC concentrations in the pre- and post-treatment soil samples within the
original treatment zone indicated that only benzo(b)fluoranthene, benzo(a)pyrene, and bis(2-
ethylhexyl)phthalate exhibited statistically significant decreases at a confidence level of 80 percent or
greater. In the revised treatment zone, benzo(b)fluoranthene, benzo(a)pyrene, chrysene, pyrene, and
fluoranthene only exhibited statistically significant decreases at a confidence level of 80 percent or greater.
Estimated mean decreases for SVOCs in the original and revised treatment zones are presented in Table 1.
Table 1. Summary of SVOC Decreases Inside Treatment Zones
contaminant Geometric Mean Percent Decrease in Geometric Mean Percent Decrease in
Original Treatment Zone Revised Treatment Zone
Benzo(b)fluoranthene 44 40
Benzo(a)pyrene 44 43
Bis(2-ethylhexyl)phthalate 55 **
Chrysene 40
Pyrene 60
;k ;k
Fluoranthene 53
** No statistically significant change at the 80 percent confidence level.
As with the TRPH data, it cannot be concluded that the changes in SVOC concentrations inside
and outside the treatment zones were a result of RFH treatment or were due solely to the application of
SVE. Pre- and post-treatment concentrations of individual VOCs were also measured, but an evaluation
of these data did not indicate any statistically significant decreases. No conclusions about changes in VOC
concentrations can be made.
The KAI RFH technology was evaluated based on the nine criteria used for decision-making in the
Superfund feasibility study process. Table 2 presents the evaluation.
XIV
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Table 2. Evaluation Criteria for the KAI RFH Technology
Evaluation Criteria
Performance
Overall Protection of Human
Health and the Environment
Compliance with Federal
ARARs1
Long-term Effectiveness and
Performance
Reduction of Toxicity, Mobility,
or Volume through Treatment
Short-term Effectiveness
Implementability
Cost2
State Acceptance
Community Acceptance
The contaminant removals achieved may not provide adequate
protection.
Requires measures to protect workers during installation and
treatment.
During the limited time period of the SITE demonstration, soil
samples exhibited estimated average TRPH decreases of 29% in the
original treatment zone and 49% in the revised treatment zone.
Vapor collection and treatment are needed to ensure compliance with
air quality standards.
Construction and operation of onsite vapor treatment unit may require
compliance with location-specific ARARs.
RF generator must be operated in accordance with Occupational
Safety and Health Administration (OSHA) and Federal
Communication Commission (FCC) requirements.
The contaminant reductions observed during the demonstration period
show that the RFH technology may not adequately remove the
contamination source.
Involves some residuals treatment (vapor stream).
Potentially reduces waste volume by volatilizing contaminants, which
are then collected (in a more concentrated form) by an SVE system.
Potentially reduces long-term contaminant mobility by volatilizing
contaminants, which are then removed from the soil and collected by
an SVE system.
Presents minimal short-term risks to workers and community from air
release during treatment.
No excavation is required, although drilling will disturb the soil to
some extent.
RF generator must be operated in accordance with OSHA and FCC
requirements.
Other pilot-scale tests have been completed; no full-scale applications
to date.
$336 per ton based upon scaling up the pilot-scale, manually- operated
system to full-scale, with 95% on-line efficiency.
No excavation is required, which should improve State acceptance.
No excavation is required, which should improve community
acceptance.
May require some community education to assure residents that the
operation of the RFH system is compliant with OSHA safety
requirements.
= Applicable or Relevant and Appropriate Requirements
Actual cost of a remediation technology is highly site-specific and dependent on the original target cleanup level, contaminant
concentrations, soil characteristics, and volume of soil. Costs associated with permitting, site preparation, analytical
programs, and residuals management were not included. Cost data presented in this table are based on the treatment of
approximately 10,000 tons of soil (95% on-line efficiency), and include costs associated with SVE. It assumes target cleanup
levels will be met within a given time frame, even though this was not observed during the demonstration.
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SECTION 1
INTRODUCTION
This section provides background information regarding the Superfund Innovative Technology
Evaluation (SITE) Program, discusses the purpose of this Innovative Technology Evaluation Report
(ITER), and describes the in situ radio frequency heating (RFH) technology developed by KAI
Technologies, Inc. (KAI). For additional information about the SITE Program, this technology, and the
demonstration site, contact the individuals listed at the end of this section.
1.1 BACKGROUND
A Demonstration Test of KAFs RFH technology was conducted by the SITE Program in
coordination with research efforts sponsored by the U.S. Air Force (USAF). Although the technology
was developed by KAI, Brown & Root Environmental (B&RE) was EPA's primary contact during the
demonstration. B&RE was hired by USAF to provide an evaluation of KAFs RFH technology. (The
USAF contract was awarded to Halliburton NUS, which has since reorganized. The work was performed
by B&RE which is owned by Halliburton NUS.) B&RE provided project and site management, designed
and operated the vapor collection and treatment systems, provided logistical support, and assisted KAI
in the onsite assembly and operation of the RFH system. KAI was subcontracted by B&RE to operate
its Mobile RFH system with an applicator design adapted for the Kelly Air Force Base (AFB) test
environment.
The KAI RFH process was demonstrated under the SITE Program from January 1994 through
July 1994 at Kelly AFB near San Antonio, Texas. The SITE demonstration was conducted at Site S-l,
located near the northern boundary of Kelly AFB. This site was historically used as an intermediate
storage area for wastes destined for offsite reclamation. The soil is contaminated with mixed solvents,
carbon cleaning compounds, and petroleum oils and lubricants. The results of the Demonstration Test
constitute the basis for this report.
The RFH technology uses electromagnetic energy in the radio frequency (RF) band to heat
contaminated soil in situ. Standard alternating current (AC) electricity is converted to RF energy by an
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RF generator. The RF energy is conveyed into the soil by one or several antennae. The design
temperature will vary from site to site, depending on the contaminants of concern. KA1 claims that the
RFH technology can be applied to soil contaminated with volatile and semivolatile organic compounds
(VOCs and SVOCs), which are volatilized when the soil is heated. Soil moisture is also volatilized
during treatment and may provide a steam sweep within the treatment zone. A vacuum is applied to the
treatment zone, and the steam and organic vapors are collected and channeled to an above-ground vapor
treatment system. A vapor barrier assists in the collection of the hot gases and prevents fugitive
emissions.
1.2 BRIEF DESCRIPTIONS OF THE SITE PROGRAM AND REPORTS
In 1986, the U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency
Response (OSWER) and Office of Research and Development (ORD) established the SITE Program to
promote the development and use of innovative technologies to clean up Superfund sites across the
country. Now in its ninth year, the SITE Program is helping to provide the treatment technologies neces-
sary to implement new Federal and State cleanup standards aimed at permanent remedies rather than
quick fixes. The SITE Program is composed of four major elements: the Demonstration Program, the
Emerging Technologies Program, the Measurement and Monitoring Technologies Program, and the
Technology Transfer Program.
The major focus has been on the Demonstration Program, which is designed to provide engineer-
ing and cost data for selected technologies. To date, the Demonstration Program projects have not in-
volved funding for technology developers. EPA and developers participating in the program share the
cost of the demonstration. Developers are responsible for demonstrating their innovative systems at
chosen sites, usually Superfund sites. EPA is responsible for sampling, analyzing, and evaluating all test
results. The final product of each demonstration is an assessment of the technology's performance,
reliability, and costs. This information is used in conjunction with other data to select the most appro-
priate technologies for the cleanup of Superfund sites
Developers of innovative technologies typically apply to the Demonstration Program by respond-
ing to EPA's annual solicitation. EPA also accepts proposals any time a developer has a Superfund waste
treatment project scheduled. To qualify for the program, a new technology must be available as apilot-
or full-scale system and offer some advantage over existing technologies. Mobile technologies are of
particular interest to EPA.
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Once EPA has accepted a proposal, EPA and the developer work with the EPA Regional Offices
and State agencies to identify a site containing waste suitable for testing the capabilities of the technology.
EPA prepares a detailed sampling and analysis plan designed to evaluate the technology thoroughly and
to ensure that the resulting data are reliable. The duration of a demonstration varies from a few days to
several years, depending on the length of time and quantity of waste needed to assess the technology.
KAI entered the SITE Program through a cooperative agreement between USAF and EPA
USAF invited EPA to participate in the demonstration to provide sampling and analytical services. EPP
would then publish reports based upon the outcome of the demonstration.
The results of the KAI RFH Technology Demonstration are published in two documents: the
ITER and the SITE Technology Capsule. The ITER includes information on demonstration costs and
performance, implementation problems/limitations, site conditions for which the technology is applicable,
waste handling requirements, and an evaluation of the technology with consideration of the nine criteria
used by remedial project managers (RPMs) during the remedial investigation/feasibility study (RI/FS)
process. The ITER also describes the demonstration, the developer's experience prior to the
demonstration, and the adaptability of the technology. The SITE Technology Capsule is a concise
summary of the ITER Both the SITE Technology Capsule and the ITER are intended for use by RPMs
making a detailed evaluation of the technology for a specific site and waste.
The second element of the SITE Program is the Emerging Technologies Program, which fosters
the further investigation and development of treatment technologies that are still at the laboratory scale.
Successful validation of these technologies can lead to the development of a system ready for field
demonstration and participation in the Demonstration Program.
The third component of the SITE Program, the Measurement and Monitoring Technologies
Program, provides assistance in the development and demonstration of innovative technologies to
characterize Superfund sites.
The fourth component of the SITE Program is the Technology Transfer Program, which reports
and distributes the results of both Demonstration and Emerging Technologies Program studies through
ITERs and abbreviated bulletins
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1.3 PURPOSE OF THE ITER
This ITER provides information on the KAIRFH technology and includes a comprehensive
description of the demonstration and its results. The ITER is intended for use by EPA RPMs, on-scene
coordinators (OSCs), contractors, and others involved in the remediation decision-making process and
in the implementation of specific remedial actions. The ITER is designed to aid decision makers in
determining whether specific technologies warrant further consideration as applicable options in particular
cleanup operations. To encourage the general use of demonstrated technologies, EPA provides
information regarding the applicability of each technology to specific sites and wastes. The ITER
includes information on cost- and site-specific characteristics. It also discusses advantages, disadvantages,
and limitations of the technology.
This report presents information useful in determining the applicability and estimated cost of
using a full-scale RPH system at a Superfund site. The proposed commercial-scale system, which utilizes
a 200-kilowatt (kW) RF generator, is described in this document. The applicability of the proposed
system and treatment costs for a full-scale remediation using the 200-kW system are presented. Costs
are presented on a per ton basis to facilitate comparison to other available technologies.
Each SITE demonstration evaluates the performance of a technology in treating a specific waste.
The waste characteristics of other sites may differ from the characteristics of the waste treated at the
demonstration site. Therefore, successful field demonstration of a technology at one site does not
necessarily ensure that it will be applicable 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.
1.4 TECHNOLOGY DESCRIPTION
RPH technologies use RF energy to heat soil in situ, thereby potentially enhancing the
performance of standard SVE technologies. The RF energy heats the soil by a dielectric heating process
that does not rely on soil permeability or conductive heat transfer mechanisms. The developer claims
that, for low thermal conductivity solids, RFH is a faster and more efficient heating mechanism than
convective or radiative heating processes. Some conductive heating also occurs in the soil. It is
potentially applicable to unsaturated (vadose zone) soils contaminated withVOCs and SVOCs. Moisture
present in the soil is also volatilized and may provide a steam sweep within the treatment zone. Steam
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and contaminant vapors are collected by a standard soil vapor extraction (SVE) system and channeled to
a vapor treatment system. The vapor treatment system is site- and contaminant-specific, and therefore
was not included in this evaluation. A basic schematic of the RFH system used during the SITE
demonstration is shown in Figure 1.
The components of the KAI RFH system have three major purposes: transmission, monitoring,
and control of RF energy; collection of vapors; and treatment of vapors. The primary components of
the system include the following:
• RF Generator — The RF generator is designed to convert 3-phase AC power to RF energy.
A typical system is designed to operate on one or more Industrial, Scientific, and Medical
(ISM) bands designated by the Federal Communications Commission (FCC). The RF
generator used during the SITE demonstration was operated at 27.12 megahertz (MHz) with
a maximum power level of 25 kW.
• Matching Network — The RFH system also includes a matching network, which allows the
RFH system to maximize the fraction of the power from the RF generator that is absorbed
by the soil. This is important for two reasons. First, the higher the fraction of power
absorbed by the soil, the more energy-efficient the system. Second, power that is not
absorbed by the soil is reflected back to the RF generator and other electrical components.
Excessive reflected power will cause the electrical components to overheat. The developer
claims that full automation of the matching network is possible. During the demonstration,
however, there was always at least one person onsite when the RF power was on.
• Diagnostic and Control System — The diagnostic and control system is used to monitor the
operation of the complete RFH system. The developer claims that the control computer
allows for complete, unattended operation with remote control and alarm functions. During
the demonstration, however, there was always at least one person onsite when the RF power
was on.
• Applicators — Energy from the RF generator flows through the matching network to the
applicators, which convey the energy into the soil. The two applicators used during the
demonstration were connected with rigid copper transmission lines that were pressurized with
nitrogen to increase their high voltage handling capability. The applicators were alternately
selected with a remote-controlled coaxial switch. Each applicator was 3.5 inches in diameter
and was constructed with aluminum, stainless steel, Teflonn, ceramic, brass, and copper
components.
• Temperature Measuring Devices — Soil temperature in and around the treatment zone is
monitored during treatment. During the SITE demonstration, soil temperatures were
measured using thermocouples, fiberoptic sensors, and infrared sensors. Temperature
measurement locations are shown in Figure 1. All sensors within the revised treatment zone
measured temperature indirectly through fiberglass walls or sand barriers. Temperature
measurements obtained from active extraction wells may have been reduced by air flowing
through the SVE system. The developer claims that there were no sensors within the revised
treatment zone that measured the instantaneous, microscopic heating of the contaminants, and
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TD1& TD2Q
/\ = antenna
Q = pressure transducer
. extraction well
3-Phase, 6OHz AC Power
TD3Q
El
1
25'kW,27.12»MHz
Power Source with ~
Instrumentation & Controls
.
r-
-
F1
a
•
F4
E2 £3
A A
W XTC1 T
.-
I Switch |
E4 F3 E5 JA2
• --Hi--^---A---
•
F5
----^ -A- =.=.=.****=** * -A
TC2
*--
.-
i
Vapor
Collection
System
TC3
O x
TD6
field profiling wells
• = thermowell
X= thermocouple string
0
TD5
1
i
i
Vapor
Treatment System
O
TD4
E6
E7
EB
0 TD7 & TD8
Figure 1. Diagram of KAI RFH system.
6
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that all sensors were likely to provide readings lower than the actual temperatures of the
materials in the heated zone. No data were provided to support these claims.
Electromagnetic Field Measuring Devices— The electromagnetic field generated by the RF
energy is measured in and around the treatment zone to determine whether the system is
complying with all regulations concerning electromagnetic fields. During the SITE
demonstration, a magnetic field sensor was inserted into five wells to monitor the
electromagnetic field within the treatment zone. Two antenna-based devices were used to
measure the electromagnetic fields above the surface: an electric field radiation hazard
sensor was used near the system, and a biconical dipole antenna was used at distances of 1
meter, 10 meters, 30 meters, and 300 meters.
Pressure Transducer Wells — Pressure transducer wells can be installed to determine the
effects of the SVE system. Prior to and during the SITE demonstration, the vacuum caused
by the SVE system was measured at the pressure transducer wells. Vacuum measurements
were also taken at the extraction wells.
Vacuum Manifold — The extraction wells feed into a vacuum manifold, which gathers the
vapors together and channels them into the vapor treatment system.
Vacuum Source — A vacuum is induced throughout the treatment zone by pulling air
through the vacuum manifold and extraction wells. During the SITE demonstration, an air
compressor and a Venturi tube were used to induce a vacuum. In a full-scale system, a
blower would typically be used.
Vapor Barrier — The system includes a vapor barrier to prevent the release of volatilized
contaminants and to help to maintain a vacuum in the treatment zone. During the SITE
demonstration, a sheet of heavy plastic served as a vapor barrier.
Vapor Treatment System — Contaminant vapors removed from the treatment zone must
typically be collected or treated. During the SITE demonstration, vapors that condensed in
the vapor collection system piping were collected as liquids. The uncondensed portion of
the vapor stream was incinerated in a propane-fueled flare. Other sites may require more
complex vapor treatment systems. Because the design of the vapor treatment system is site-
and contaminant-specific, the vapor treatment system used during the SITE demonstration
is not included in this evaluation.
The RFH system is transported to the site in a trailer with a removable steel shelter that houses
the RF generator, matching network, and diagnostic and control equipment. The onsite assembly of the
RFH system begins with the installation of the subsurface components. Extraction wells, temperature
measurement wells, electromagnetic field measurement wells, and fiberglass borehole liners for the
applicators are installed by drilling a hole to the required depth, inserting the appropriate component, and
backfilling around the component. Support structures positioned above the applicator boreholes are used
to insert the applicators into the fiberglass borehole liners. A portion of each subsurface component must
extend above the surface to allow connection to the appropriate above-ground portion of the system.
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After all subsurface components are installed, the vapor barrier is placed over the treatment zone.
Holes are cut in the vapor barrier to allow connections between the subsurface components and the above-
ground portions of the system. The vapor barrier is then sealed around each connection. Extraction
wells are connected to the vapor treatment system through the vacuum manifold. Thermocouples are
connected to monitoring instruments. The applicators are connected to the coaxial switch with RF
transmission lines.
After all subsurface components are installed, the vapor barrier is placed over the treatment zone.
Holes are cut in the vapor barrier to allow connections between the subsurface components and the above-
ground portions of the system. The vapor barrier is then sealed around each connection. Extraction
wells are connected to the vapor treatment system through the vacuum manifold. Thermocouples are
connected to monitoring instruments. The antennae are connected to the RF generator and
instrumentation by 1-5/8" rigid copper transmission lines.
After installation and assembly, the system is tested and any necessary adjustments are made.
If desired, the SVE system may be operated before heat is applied to the soil. The SVE system continues
to operate as the RF system is activated and heat is applied to the soil. The RF energy is applied to the
soil until the termination criteria are met. Termination criteria should be established prior to the
remediation effort based on treatability study results, site characterization data, and target cleanup levels.
For application of RFH at Super-fund sites, factors such as average soil temperature in the treatment zone
over a specified amount of time and contaminant concentrations in the vapor stream should be considered
when determining termination criteria. The termination criteria may require adjustment based on
information collected during treatment.
Because of time and funding constraints imposed on the developer by USAF, RFH was applied
for a predetermined number of days before the RF power was turned off. These termination criteria may
have limited the RFH system's ability to reach the target removal level.
After treatment is complete, the treatment zone must be allowed to cool. If the treatment zone
did not encompass all of the contaminated soil at the site, the above-ground components of the RFH
system can be disassembled, moved to another portion of the site, and reassembled while the soil in the
treatment zone cools. If the commercial-scale system includes two sets of subsurface components,
treatment of a second zone can begin while the first zone is cooling. During the SITE demonstration,
8
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the soil was allowed to cool for 1 month prior to post-treatment sampling. The SVE system was operated
for the first 14 days of the cool-down period.
After the treatment zone cools, post-treatment soil samples are collectedto determine the extent
of treatment. Depending upon local regulations, it may be necessary to remove all subsurface
components, and then redrill and seal all boreholes. During the SITE demonstration, it was necessary
to redrill all boreholes and seal them with bentonite at the end of the test.
1.5 KEY CONTACTS
For more information on the demonstration of the KAI in situ RFH technology, please contact:
EPA Project Manager for the SITE
Demonstration Test:
Ms. Laurel Staley
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
(513) 569-7348
Process Vendor:
Mr. Raymond Kasevich
KAI Technologies, Inc.
170 West Road, Suite?
Portsmouth, NH 03801
(603) 431-2266
Kelly AFB Project Engineer:
Ms. Victoria Wark
SA/ALC/EMRO
305 Tinker Drive, Suite 2, Building 305
Kelly AFB, TX 78241-5915
(210) 925-1812
USAF Technical Program Manager, Site
Remediation Division:
Mr. Paul F. Carpenter
AL/EQW-OL
139 Barnes Drive, Suite 2
Tyndall AFB, FL 32403
(904) 283-6187
B&RE Project Manager:
Mr. Clifton Blanchard
B&RE
800 Oak Ridge Turnpike, Suite A600
Oak Ridge, TN37830
(615) 483-9900
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Information on the SITE Program is also available through the following on-line information
clearing houses:
• The Alternative Treatment Technology Information Center (ATTIC) is a comprehensive,
automated information retrieval system that integrates data on hazardous waste treatment
technologies into a centralized, searchable source. This data base provides summarized
information on innovative treatment technologies. The system operator can be reached at
(703) 908-2137, and system access is available at (703) 908-2138.
• The Vendor Information System for Innovative Treatment Technologies (VISITT) data base
contains information on 154 technologies offered by 97 developers, (800) 245-4505.
• The OSWER CLU-IN electronic bulletin board contains information on the status of SITE
technology demonstrations. The system operator can be reached at (301) 589-8268.
Technical reports can be obtained by contacting the EPA Center for Environmental Research
Information (CERI), 26 West Martin Luther Ring Drive, Cincinnati, Ohio 45268 at (513) 569-7562.
10
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SECTION 2
TECHNOLOGY APPLICATIONS ANALYSIS
This section addresses the applicability of the KAI in situ RFH technology to the remediation of
soils contaminated with VOCs and SVOCs. Conclusions are based on results obtained from the SITE
demonstration as well as additional data provided by KAI and B&RE. The results of the SITE
demonstration are presented in Section 4 and supplementary data from the demonstration are presented
in Appendix A. The results of previous RFH treatability studies are summarized in Appendix B.
2.1 OBJECTIVES: PERFORMANCE VERSUS ARARS
This subsection discusses specific environmental regulations pertinent to the operation of the KAI
RFH system, including the transport, treatment, storage, and disposal of wastes and treatment residuals.
The impact of these regulations will be evaluated in light of the demonstration results. State and local
regulatory requirements, which may be more stringent, will also have to be addressed by RPMs.
Applicable or relevant and appropriate requirements (ARARs) may include regulations associated with
the following: the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA); the Resource Conservation and Recovery Act (RCRA); the Clean Air Act (CAA); the Safe
Drinking Water Act (SDWA); the Clean Water Act (CWA); the Toxic Substances Control Act (TSCA);
and Occupational Safety and Health Administration (OSHA) regulations. These seven general ARARs
are discussed in the following subsections; specific ARARs must be identified by RPMs for each site.
Some specific Federal and State ARARs that may be applicable to the KAI RFH technology are identified
and discussed in Table 3.
2.1.1 CERCLA
CERCLA of 1980, as amended by the Superfund Amendments and Reauthorization Act (SARA)
of 1986, provides for Federal funding to respond to releases of hazardous substances to air, water, and
land. Section 121 of SARA, Cleanup Standards, states a strong statutory preference for remedies that
are highly reliable and provide long-term protection. It strongly recommends that remedial actions use
onsite treatment that " permanently and significantly reduces the volume, toxicity, or mobility of
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Table 3. Potential Federal and State ARARs for the Treatment of Contaminated Soil by the KAI RFH System
at a Superfund Site
Process Activity
Waste
characterization
(untreated waste)
Storage prior to
processing
Waste processing
Storage after
processing
ARAR
RCRA' 40 CFR2 Part 261 or
State equivalent
TSCA3 40 CFR Part 761 or
Stale equivalent
< 90 days: RCRA 40 CFR
Part 262 or State equivalent
> 90 days: RCRA 40 CFR
Part 264 or State equivalent
RCRA 40 CFR Part 264 or
State equivalent
CAA4 40 CFR or Stale
equivalent
RCRA 40 CFR Part 264 or
Stale equivalent
TSCA 40 CFR Part 761.65
Description
Identification and charactetization of
the soil to be treated.
Standards that apply to the treatment
and disposal of wastes containing
polychlotinated biphenyls (PCBs).
Standards applicable to the storage of
hazardous waste in containers or tanks.
Standards applicable to the treatment of
hazardous waste at permitted facilities.
Standards applicable to emissions from
treatment equipment.
Standards that apply to the storage of
hazardous waste in containers or tanks.
Standards that apply to storage of
wastes containing F'CBs.
Basis
A requirement of RCRA prior to managing the
waste.
During waste characterization, PCBs may be
identified in the waste and, if present above
regulatory thresholds (50 ppm for TSCA), the
waste is subject to TSCA regulations.
Contaminated groundwater extmcted by
dewateting wells and soil cuttings from
boreholes meeting the definition of hazardous
waste must meet substantive requirements of
RCRA storage regulations.
Treatment of hazardous waste must be conducted
in a manner that meets the substantive
requirements of a RCRA Part B permit.
Air emissions may have to be controlled to meet
the substantive requirements of CAA permit.
Contaminated groundwater extmcted by
dewateting wells, condensate, spent carbon (if
used), and soil cuttings from boreholes meeting
the definition of hazardous waste must meet
substantive requirements of RCRA storage
regulations.
Groundwater, condensate, spent carbon (if used),
and soil cuttings may contain PCBs above
regulatory thresholds.
Response
Chemical and physical analyses must
be performed.
Analysis for PCBs must be
performed if potentially present.
Ensure storage containers and tanks
are in good condition, provide
secondary containment, when
applicable, and conduct regular
inspections.
Equipment must be operated,
maintained, and monitored properly.
Emission control devices may need
to be installed to treat air emissions
from the SVE unit.
The contaminated groundwater,
condensate, and soil cuttings must be
stored in containers or tanks that are
well maintained.
Ensure disposal of TSCA-regulated
wasle within 1 year of placement
into stomge.
1 RCRA is the Resource Conservation and Recovery Act. 5
2 CFR is the Code of Federal Regulations. 6
3 TSCA is the Toxic Substances Conlrol Act. 7
4 CAA is the Clean Air Act.
CWA is the Clean Waler Act.
SDWA is the Safe Drinking Water Act.
DOT is the Department of Transportalion.
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Table 3. (continued)
Process Activity
ARAR
Description
Basis
Response
Waste
characlerizalion
(treated waste and
residuals)
RCRA 40 CFR Part 261 or
Stale equivalent
Identification and characterization of in
situ soil, soil cuttings, spent carbon (if
used), groundwaler, and condensate.
A requirement of RCRA prior lo managing the
waste necessary to determine regulatory status of
in situ soil.
Chemical and physical testa must be
performed on the in situ soil,
groundwater, soil cutting:, and
condensale.
TSCA 40 CFR Part 761 or
Stale equivalent
Standards that apply to the treatment
and disposal of wastes conlaining
PCBs.
Soil cuttings, spent carbon (if used), and
condensale may contain PCBs above regulatory
thresholds.
Analysis for PCBa must be
performed if PCBs were present ia
untreated soil.
Transporlalion
for offsite
disposal
RCRA 40 CFR Part 262 or
State equivatenl
Manifesting, packaging, and labeling
requirements prior to transporting.
The contaminated groundwater, condensate, and
soil cuttings may need to be manifested and
managed as a hazardous waste.
An identification (ID) number must
be obtained from EPA.
RCRA 40 CFR Part 263 or
Slale equivalent
Packaging, labeling, and transportation
standards.
Transporters of hazardous waste must be
licensed by EPA and meet specific requirements.
A licensed hazardous waste
transporter must be used to transport
the hazardous waste.
DOT 49 CF'R
Hazardous malerials must meet specific
packaging and labeling requirements.
Shipments of material must be
properly containerized and labeled.
Groundwaler and
condensale
discharge
CWA5 40 CFR Parts 301,
304.306,307,308, 402, and
403
Standards that apply to discharge of
contaminated water into sewage
treatment plants or surface water
bodies.
The groundwater and condensate may not meet
local pretreatment standards without further
treatment or may require a NPDES permit for
discharge 10 surface waler bodies.
Determine if the groundwater and
condensate could be discharged to a
sewage treatment plant or surface
waler body without further
treatment. If not, Ihe water may
need to be further treated lo meet
discharge requirements.
SDWA6 40 CFR Parts 144 and
145
Standards that apply lo the disposal of
contaminaled waler in underground
injection wells (including infiltration
galleries).
Injection of the groundwaler and condensate may
be the preferred oplion for management of water
from treatment at remole sites.
If underground injection is selected
as a disposal means for treated
waler, testing musl be performed
and permission must be obtained
from EPA to use existing permitted
underground injection wella or 10
construct and operate new wells.
I RCRA is the Resource Conservation and Recovery Act.
2 CFR is the Code of Federal Regulations.
3 TSCA is the Toxic Subslances Control Act.
4 CAA is the Clean Air Act.
5 CWA is the Clean Water Act.
6 SDWA is the Safe Drinking Water Act.
7 DOT is the Department of Transportation.
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hazardous substances. " In addition, the nine criteria used by RPMs during the RI/FS process must be
addressed by CERCLA remedial actions. The criteria include:
• Overall protection of human health and the environment
• Compliance with ARARs
• Long-term effectiveness and permanence
• Reduction of toxicity, mobility, or volume
• Short-term effectiveness
• Implementability
• cost
• State acceptance
• Community acceptance
The performance of KAFs RFH technology in each of these nine categories was evaluated, and
the results are presented in Table 1 in the Executive Summary.
2.1.2 RCRA
RCRA is the primary Federal legislation governing hazardous waste activities. Although a RCRA
permit is not required for hazardous waste treatment for onsite remedial actions at Superfund sites, the
KAI RFH system must meet all of its substantive requirements if treating a hazardous waste. RCRA
administrative requirements such as reporting and recordkeeping, however, are not applicable for onsite
actions. Subtitle C of RCRA contains requirements for generation, transport, treatment, storage, and
disposal of hazardous waste. Compliance with these requirements is mandatory for CERCLA sites
producing hazardous waste onsite.
The substantive requirements of a Part B Treatment, Storage, and Disposal (TSD) permit may
be required when the soil undergoing treatment is considered to be hazardous. Invariably, a Uniform
Hazardous Waste Manifest must accompany offsite shipment of RCRA hazardous wastes, and transport
must comply with Federal DOT hazardous waste packaging, labeling, and transportation regulations. The
receiving TSD facility must be permitted and in compliance with RCRA standards. The RCRA land
disposal restrictions (LDR) in 40 CFR 268 preclude the land disposal of hazardous waste that fails to
meet stipulated treatment standards. The technology or treatment standards applicable to the residuals
produced by the KAI RFH system will be determined by the characteristics of the material treated and
14
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the residuals generated. Wastes that do not meet these standards must receive additional treatment to
bring the wastes into compliance with the standards prior to land disposal, unless a variance is granted.
2.1.3 CAA
The CAA establishes primary and secondary ambient air quality standards for the protection of
public health and emissions limitations for certain hazardous air pollutants. Requirements under the CAA
are administered by each state as part of the State Implementation Plans developed to bring each state into
compliance with the National Ambient Air Quality Standards (NAAQS). The ambient air quality
standards listed for specific pollutants will generally be applicable to the operation of the RFH system,
since it volatilizes contaminants and removes them from the soil as vapors. A vapor barrier and vapor
collection system (described in Subsection 1.4) prevent the release of these contaminants to the air. The
system that will be used to treat the collected vapors varies depending on the location of the site and the
contaminants present. The vapor treatment system must be designed in compliance with the CM. The
operating permits required and allowable emission limits must be evaluated on a case-by-case basis.
The vapor treatment system employed during the SITE demonstration consisted of condensate
collection and a propane-fueled flare. According to B&RE, the flare was operated under Standard
Exemption Number 68 as defined in Section 382.057 of the Texas Clean Air Act. The vapor stream
prior to the flare was periodically sampled prior to, during, and after RFH treatment. Vapor stream data
are presented in Appendix A.
2.1.4 SDWA
SDWA establishes primary and secondary national drinking water standards. CERCLA refers
to these standards and Section 121(d)(2) explicitly mentions two of these standards for surface water or
groundwater: Maximum Contaminant Levels (MCLs) and Federal Water Quality Criteria. Alternate
Concentration Limits (ACLs) may be used when conditions of Section 121 (d)(2)(B) are met and cleanup
to MCLs or other protective levels is not practicable. Included in these sections is guidance on how these
requirements may be applied to Superfund remedial actions. The guidance, which is based on Federal
requirements and policies, may be superseded by more stringent promulgated State requirements, resulting
in the application of even stricter standards than those specified in Federal regulations.
15
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Approximately 2,000 gallons of condensate were collected from the vapor treatment system and
transferred to the Kelly AFB industrial wastewater treatment facility for treatment. In other applications
of the RFH technology, the amount of condensate generated and the contaminants present in the
condensate will depend on the temperature to which the soil is heated, the moisture content of the soil,
the contaminants present in the soil, and the design of the vapor treatment system. Aqueous residuals
were also generated during equipment and personnel decontamination and treated as the condensate above.
If commercial applications of the RFH technology require dewatering to lower the water table,
groundwater residuals will also be generated.
2.1.5 CWA
CWA regulates direct discharges to surface water through the National Pollutant Discharge
Elimination System (NPDES) regulations. These regulations require point-source discharges of
wastewater to meet established water quality standards. The discharge of wastewater to a sanitary sewer
requires a discharge permit or, at least, concurrence from State and local regulatory authorities that the
wastewater is in compliance with regulatory limits. As discussed in Subsection 2.1.4, the aqueous
residuals generated during the SITE demonstration were condensate from the vapor treatment system and
washwater from equipment and personnel decontamination.
2.1.6 TSCA
The treatment and disposal of asbestos and materials containing PCBs at concentrations of 50
parts per million (ppm) or greater are regulated by TSCA. Asbestos is not generally present at the type
of site that would be remediated using the RFH technology. It is possible that the RFH technology could
be used to treat soil that contains PCBs The regulation of treatment of PCB-contaminated materials is
based on PCB concentration. Materials containing PCBs in concentrations between 50 and 500 ppm may
be disposed of in TSCA-permitted landfills or incinerated in TSCA-approved incinerators; materials
containing PCBs in concentrations greater than 500 ppm must be incinerated. It is permissible, however,
to use other technologies to reduce the volume of material containing PCBs in concentrations less than
500 ppm. If RFH was used to treat material containing PCBs, the PCB vapors would require collection
and condensation followed by disposal in accordance with TSCA.
Sites where PCB spills have occurred after May 4, 1987, must be addressed under the PCB Spill
Cleanup Policy in 40 CFR Part 761, Subpart G. The policy applies to spills of materials containing PCBs
16
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in concentrations of 50 ppm or greater and establishes cleanup protocols for addressing such releases
based on the volume and concentration of the spilled material.
2.1.7 OSHA Requirements
CERCLA remedial actions and RCRA corrective actions must be performed in accordance with
OSHA requirements detailed in 20 CFR Parts 1900 through 1926, especially Part 1910.120, which
provides for the health and safety of workers at hazardous waste sites. Onsite construction activities at
Superfund or RCRA corrective action sites must be performed in accordance with Part B of OSHA,
which provides safety and health regulations for construction sites. State OSHA requirements, which may
be more stringent than Federal standards, must also be met.
All personnel involved in the operation of the KAI RFH system must have completed a 40-hour
OSHA training course covering personal protective equipment (PPE), safety and health, emergency
response procedures, and quality assurance/quality control (QA/QC). Additional training addressing the
site activities, procedures, monitoring, and equipment associated with the technology is also necessary.
Training provided prior to the operation of the system should include information regarding emergency
evacuation procedures; safety equipment locations; the boundaries of the exclusion zone, contaminant
reduction zone, and support zone; and PPE requirements. Onsite personnel must also participate in a
medical monitoring program. Health and safety monitoring and incident reports should be routinely filed,
and records of occupational illnesses and injuries (OSHA Forms 102 and 200) should be maintained.
Audits ensuring compliance with the health and safety plan should be carried out.
Proper PPE should be available and properly utilized by all onsite personnel. At each site, the
level of PPE required will be determined based on the potential hazards associated with the site and the
work activities being conducted.
OSHA has also provided guidance, published in 20 CFR Part 1910.97, for exposure to
electromagnetic radiation in the RF region. This guidance states that "for normal environmental
conditions and for incident electromagnetic energy of frequencies from 10 MHz to 100 gigahertz (GHz),
the radiation protection guide is 10 mW/cm2 (milliwatt per square centimeter) as averaged over any
possible 0.1-hour period. " This means that a power density of 10 mW/cm2 for periods of 0.1 hour or
more or an energy density of 1 mW-hr/cm2 during any 0.1-hour period should not be exceeded without
careful consideration of the reasons for doing so.
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2.2 OPERABILITY OF THE TECHNOLOGY
KAFs RFH system is described in Subsection 1.4. The components of an RFH system have three
major purposes: heating the soil by applying RF energy to it, collecting vapors released by the heated
soil, and treating those vapors. During the SITE demonstration, KAI was subcontracted by B&RE to
design and operate the RFH system, but not the vapor collection and vapor treatment systems. B&RE
provided project and site management, designed and operated the vapor collection and treatment systems,
and assisted KAI in the construction and operation of the RFH system.
Several problems were encountered in the implementation of KAFs RFH system. Start-up was
delayed because the chosen frequency required the approval of both the FCC and the Air Force
Frequency Manager. This delay may not be expected to occur at all remedial sites. There was also
significant downtime after start-up because of problems with the 3-phase AC power transmission system.
The instability of the AC power available to the RFH system caused occasional shutdown. The AC
power problem also contributed to the need to adjust the RF generator. In addition, it was periodically
necessary to discontinue the application of RF energy to allow the borehole liner to cool, although
borehole cooling tubes were later installed to minimize this problem.
Operating parameters that affect the performance of the RFH system include treatment
temperature and duration of treatment. The treatment temperature determines the rate at which
contaminants are volatilized as well as the range of contaminants that will be volatilized. Both the
treatment temperature and the duration of treatment influence the final contaminant concentrations.
Operating temperature and treatment time are typically selected based on the contaminants of concern and
the required cleanup levels. Based on input from USAF; its contractor, B&RE; and the developer, KAI,
the SITE Demonstration Plan specified total recoverable petroleum hydrocarbons (TRPH) as the primary
contaminant of concern, 1 SOT as the operating temperature, and approximately 6 weeks as the treatment
tune. Because of the expected low initial concentrations, decreases of VOCs and SVOCs were listed as
secondary objectives.
Just prior to system installation, KAI and B&RE changed the planned operation of the system.
They targeted only volatile organics, specifically gasoline-range hydrocarbons, as the contaminants of
concern, which allowed KAI to lower the treatment temperature range to 100 to 130°C. (these changes
were not reflected in the SITE Demonstration Plan because the SITE Program was not notified until after
the demonstration was completed.)
18
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The design and operation of the vapor collection and vapor treatment systems will also affect
performance. Factors that can be varied include the number, location, spacing, and design of the
extraction wells; the amount of vacuum applied to the vapor collection system; the air flow rate through
the vapor collection system; the amount of time for which the vapor collection system is operated (it can
be operated after the application of heat to the treatment zone has been discontinued); and the components
of the vapor treatment system.
2.3 APPLICABLE WASTES
The RFH technology is potentially capable of remediating soils contaminated with VOCs and
SVOCs, including petroleum hydrocarbons. According to KAI, the maximum temperatures that can be
sustained are in the 300 to 400°C range. SVOCs with boiling temperatures below this range are suitable
candidates for RFH. Inorganics, metals, and other nonvolatile contaminants will not normally be
removed
KAFs RFH technology is best applied to contaminated soil in the vadose zone. If saturated soil
is to be remediated by RFH, the treatment zone should be dewatered prior to treatment. If the water
table is close to the contaminated soil and the groundwater is also contaminated, it may be difficult to heat
the soil without volatilizing contaminants in the groundwater, which can be more effectively treated by
another method.
Although the economics of treatment by this technology are not favorable for saturated soils (i.e.,
the cost of treating saturated soils by this technology exceeds the treatment costs incurred by using other
technologies, such as pump and treat), it is applicable to unsaturated soils regardless of moisture content.
Theoretically, RF energy preferentially heats polar molecules, and water molecules are strongly polar.
As a result, moist soils can provide improved absorption of the RF energy. However, this also means
that moist soils will require additional energy, particularly if the target soil temperature is above the
boiling point of water. At soil temperatures above 100°C, chemically-bound water molecules continue
to absorb RF energy. The dielectric constant of the soil determines the soil's ability to absorb RF energy
directly. Other than the impact of the soil dielectric constant, RFH should be applicable to any soil type.
Soil type will, however, impact the operation of the SVE system. For example, soils containing
a large fraction of clay may have low air permeability. Theoretically, RFH may enhance the air
permeability of soil by removing moisture from it. Since RFH is a technology designed to enhance SVE
19
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performance, site conditions that limit the effectiveness of SVE will affect the level of enhancement
achievable by RFH.
2.4 KEY FEATURES OF THE KAI RFH TECHNOLOGY
KAFs RFH technology is similar to both in situ steam extraction and in situ SVE. In SVE,
vacuum blowers induce air flow through the soil, stripping VOCs and SVOCs from it [1]. In steam
extraction, steam is injected into the ground to raise the soil temperature and strip VOCs and SVOCs
from it [2]. The primary difference between these technologies and RFH is that RFH uses RF energy
to heat the soil in the treatment zone. Because the RFH technology uses higher temperatures, it is more
aggressive than either steam extraction or SVE. Theoretically, RFH can therefore be applied to less
volatile contaminants.
2.5 AVAILABILITY AND TRANSPORTABILITY OF SYSTEM
KAI owns and operates one 25-kW RFH system, which was used for the SITE demonstration.
The assembly of this system is a multistep process. The applicators and the installation towers were all
shipped as part of the same truck/trailer system that contained the RFH system. The extraction wells,
pressure transducer wells (if used), electric field measurement wells (if used), thermowells, and antennae
are installed in boreholes. After the subsurface components are installed, above-ground wiring and piping
is completed and the vapor collection and treatment systems are connected to the subsurface components.
The assembly of the proposed 200-kW RFH system will be similar to the assembly of the existing
25-kW system. It is projected that the 200-kW system will be transported on four trailers. The system
will use more antennae and extraction wells than the pilot-scale system, but the multistep installation
process will be the same.
For both pilot-scale and commercial-scale projects, the vapor treatment system will vary from
site to site. During the SITE demonstration, the vapor treatment system consisted primarily of a
condensate collection system and a propane-fueled flare. The flare was mounted on a trailer, and the
condensate collection system was assembled onsite An air compressor and instrumentation for the vapor
treatment system were installed in a small building that was constructed for the demonstration.
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2.6 MATERIALS HANDLING REQUIREMENTS
Materials handling requirements prior to treatment are minimal because this is an in situ system.
Although not evaluated during this demonstration, KAI claims that soil removed from boreholes during
the installation of the electrodes and thermowells may be placed on top of the treatment zone and treated
with the undisturbed soil. If the soil cuttings are not treated with the undisturbed soil, they must be
treated or disposed of in some other fashion.
Depending on its design, the vapor treatment system may generate residuals. The 'materials
handling requirements for these residuals will vary depending on the design of the vapor treatment system
and the contaminants present in the soil. During the SITE demonstration, uncondensed vapors were
channeled directly to a propane-fueled flare. Vapors that condensed in the vapor treatment system were
collected in a 55-gallon drum, and then transferred to the Kelly AFB industrial wastewater treatment
facility for treatment and disposal. The residuals generated by the vapor treatment system of a
commercial-scale RFH system will depend on the vapor treatment system used and the nature of the site
being remediated.
Another aqueous residual generated during the RFH SITE demonstration was the washwater from
personnel and equipment decontamination. Commercial applications of the RFH technology will also
generate groundwater residuals if dewatering is employed.
2.7 SITE SUPPORT REQUIREMENTS
Remediation using the RFH process will require that certain utilities be available at the site.
Water must be available for steam-cleaning the drill rig and auger and for other equipment and personnel
decontamination activities. Electrical power must also be available. It is projected that 480-volt, 3-phase
power will be needed at an onsite distribution point and that a 3-phase 480- to 240-volt transformer will
be needed to establish the required single-phase service. The primary component connected to the 480-
volt, 3-phase power will be the RF generator; the majority of the minor system components will use 240-
volt, single-phase power.
A mobile drill rig and drill crew will be required onsite for the installation of the subsurface
components. Depending upon local regulations, it may also be necessary to remove all subsurface
components after treatment, and then redrill and backfill all boreholes. During the SITE demonstration,
21
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it was necessary to redrill all boreholes and backfill them with bentonite at the end of the test. The drill
rig will also be used to install dewatering wells, if dewatering is necessary. A fork lift truck and operator
will be required during disassembly. Onsite storage requirements include temporary storage for residuals
collected from the vapor treatment system (if any), groundwater collected during dewatering (if
dewatering is required), and water used in decontamination activities.
2.8 LIMITATIONS OF THE TECHNOLOGY
In general, KAI's RFH technology is not recommended for the remediation of saturated soils.
If saturated soil is to be remediated by RFH, the treatment zone should be dewatered prior to treatment.
This will add to the total treatment cost and may not be effective, depending on the local hydrogeologic
conditions. If the water table is close to the contaminated soil and the groundwater is also contaminated,
it may be difficult to heat the soil without volatilizing contaminants in the groundwater which can more
effectively treated by another method.
KAI's RFH system can only be used to remove contaminants that can be volatilized at soil
temperatures that the system can practically achieve throughout the treatment zone. This limits the
technology to soil contaminated with VOCs and SVOCs, since nonvolatile organics, metals, and
inorganics will not normally be removed at temperatures the system can achieve.
Contaminants in silty or clayey soils are usually strongly sorbed and difficult to remove. Clayey
soils may also have insufficient air permeability for adequate extraction of vaporized contaminants.
Vacuum extraction of vapors from heterogeneous soils may also be difficult. Extraction of vapors from
such soils frequently bypasses lower-permeability zones, leaving contaminants behind.
The SITE demonstration provides an example of the application of KAI's RFH system to
heterogeneous soil. The demonstration treatment zone included highly permeable zones, containing
primarily gravel and sand, as well as less permeable zones, containing a significant percentage of silt and
clay. As will be discussed in Section 4, significant residual contamination was measured in the treatment
zone after the SITE demonstration. It is not clear, however, whether this indicates a limitation of the
system or a problem with the implementation of the system. Because only a portion of the revised
treatment zone reached the target temperature range of 100 to 130*0, it is possible that the system was
not allowed to operate long enough to achieve an adequate treatment temperature. This was at least partly
due to the amount of time available for treatment and problems with the electrical power source. The
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design and operation of the SVE system may have also adversely affected contaminant decreases.
As discussed in Subsection 2.2, problems with the 3-phase AC power transmission system led
to significant downtime at the beginning of the SITE demonstration. If adequate power is not available
at a site, it must be produced by a generator.
2.9 REFERENCES
1. Engineering Bulletin: In Situ Soil Vapor Extraction Treatment. EPA/540/2-91/006, May 1991.
2. Engineering Bulletin: In Situ Steam Extraction Treatment. EPA/540/2-91/005, May 1991.
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SECTION 3
ECONOMIC ANALYSIS
3.1 INTRODUCTION
The primary purpose of this economic analysis is to estimate the costs (not including profit) for
a commercial-scale system using KAFs in situ RFH technology to remediate 10,940 tons of soil
contaminated with volatile and semivolatile organics. This analysis is based upon on the results of a SITE
demonstration that utilized KAFs pilot-scale RFH system, information from previous tests conducted by
KAI, and information obtained from engineering textbooks.
3.2
BASIS OF ECONOMIC ANALYSIS
The cost analysis is typically prepared by breaking down the overall cost into 12 categories. The
cost categories, and the areas that each of them generally comprise, are listed below. As presented, not
all categories are included in the economic analysis associated with this document.
Site preparation
— site design and layout
— surveys and site logistics
™ legal searches
aceea right* afKt roads
.land clearing
— preparations for support and decontamination facilities
utility connections
— auxiliary buildings
Permitting and regulatory
™ ICIIM! peraiit coils
— system monitoring requirements
'Equipment
™- equipreent used during treatiiiei&l
— freight
sties tax
Startup snd Sxeci
transportation of personnel So the site
wageu tod living expenses
assembly of the unit
— shakedown, testing, and training
—'• working capital
— insurance
contingencies
property taxes
process monitoring equipment
engineering and supervision
Operating costs for treatment
— tabor
— fabrication
drilling
Supplies
— spare part*
— bentonite
Consumables
— electricity
water
diesei fuel
Effluent, treatment and disposal
— further treatment/disposal of effluent(s)
— onsite storage of effluent(s)
Residuals and waste shipping, handling, and transport.
storage of residuals/wastes
transportation of residuals/wastes
— treatment/disposal of residuals/wastes
Analytical services
— sampling and analytical program
Facility modification, repair, and replacement
maintenance material costs
— design adjustments
equipment replacements
Site demobilization
disassembly costs
— site cleanup and restoration
— wages and living expenses
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3.3 ISSUES AND ASSUMPTIONS
This subsection summarizes the issues and assumptions of the economic analysis for this study.
The objective of this SITE demonstration was to treat a single cell having dimensions of 15 feet by 10
feet by 20 feet (111 cubic yards or 171 tons) using a25-kW system. This economic evaluation was based
on the original design of the RFH system for the demonstration. Because of the problems encountered
during the demonstration, several assumptions had to be made about the technology. Even though no
conclusions about the success of RFH at Kelly AFB can be made, the economic evaluation assumes the
technology will meet target cleanup levels within a given timeframe.
For this analysis, the goal was to estimate remediation costs of a full-scale system based upon a
site of approximately 10,000 tons at a depth of 20 feet. The size of the full-scale system is estimated to
be 200-kW (modular system of eight 25kW generators). Therefore, a factor of eight was used to scale-up
the system used in the SITE demonstration to the full-scale level. Desiring to keep the length of the cell
at 1.5 times its width, the cell dimensions at the full-scale level would be approximately 42 feet by 28
feet by 20 feet (900 cubic yards or approximately 1,400 tons). Based upon these dimensions, it was
determined that the mass of eight cells (10,940 tons) would be the mass used for this analysis since it
most nearly met the 10,000 ton goal. The full-scale site is assumed to be 2 cells in length by 4 cells in
width. It is assumed the full-scale cleanup will proceed along the width of the site, allowing savings to
occur due to the overlapping of extraction well rows. The exact configuration of the full-scale system
in each cell is site-specific and is not included in this analysis.
It is assumed that the frequency of operation of the 200-kW unit will be 13.56 MHz. It is also
assumed that the RFH system will operate 24 hours per day, 7 days per week with a 95 percent on-line
time. Therefore, the total estimated time the equipment will be onsite is 76 weeks.
A utilization factor of 90 percent was assumed. The utilization factor is used to adjust the unit
treatment cost to compensate for the fact that the system is not leased to a client at all times because of
limited market demand for this type of technology. Through the use of the utilization factor, costs
incurred while the system is not leased out are incorporated into the unit cost and distributed evenly to
all occasions when the system is applied to a project. Costs that accrue when the system is not in use
include insurance, taxes, and capital equipment costs.
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The cost of the SVE system is generally a significant part of the RFH treatment costs. Therefore,
to estimate the SVE system as a percentage of the treatment costs, it was assumed that the SVE system
would incur 50 percent of the following costs:
• Insurance • Labor during treatment
• Electrical • Labor during fabrication
• Freight • Electricity
• Tax • Site demobilization and transportation
• Labor during startup • Labor during site demobilization
• Assembly
The primary pieces of equipment of the SVE system used in this cost analysis are PVC pipes
for extraction wells and above-grade conduit, and a well junction box.
The following subsections (Subsections 3.3.1 through 3.3.12) describe assumptions that were
made in determining project costs for 7 of the 12 cost categories. This analysis does not include cost
values for: site preparation; permitting and regulatory; effluent treatment and disposal; residuals and
waste shipping, handling, and transport; and sampling and analytical services. Costs for these categories
are highly dependent upon site-specific factors, and therefore, no estimates are presented in this economic
analysis. Consequently, the actual cleanup costs incurred by the site owner or responsible party may be
significantly higher than the costs shown in this analysis. The actual cost is expected to fall between 70
percent and 150 percent of this estimate. This level of accuracy is accepted by the SITE Program as
appropriate for generating estimates without the benefit of detailed engineering data [1]. However, since
this cost estimate is based on a preliminary design, the range may actually be wider.
According to Plant Design and Economics for Chemical Engineers [2], insurance, property taxes,
spare parts, contingency costs, and maintenance materials can be estimated as a percentage of the fixed
capital investment required for a project. The components of the fixed capital investment that apply to
this project are:
• Total equipment cost applied to the project (including freight and sales tax)
• Supply of spare parts (5 percent of fixed capital investment)
• Transportation (other than freight)
• Assembly
• Shakedown, testing, and training
• Contingencies (10 percent of fixed capital investment)
• Engineering and supervision for system installation
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Since some of these components are estimated independently of the fixed capital investment (e.g.,
assembly), and others are percentages of the fixed capital investment applied to the project (e.g.,
contingencies), a formula for calculating the fixed capital investment was developed.
The vendor claims that the treatment cost estimate presented in this analysis may be significantly
higher than the actual cost since some components of the RFH system used in the SITE demonstration
may not be required in the full-scale system. Vendor claims are presented in Appendix C.
3.3.1 Site Preparation
The amount of preliminary site preparation required is highly dependent on the site.
Consequently, site preparation costs are not included in this cost estimate and are assumed to be the
responsibility of the site owner or responsible party. It is essential to consider that site preparation
measures may significantly increase the costs associated with the use of this technology.
3.3.2 Permitting and Regulatory
Permitting and regulatory costs can vary greatly because they are site- and waste-specific.
Consequently, no permitting or regulatory costs are included in this analysis. This category may be a
significant factor in determining project costs since permitting activities can be both expensive and time
consuming.
3.3.3 Equipment
The primary pieces of equipment of the KAI RFH system include:
• RF generator and tuner
• Antennae
• Extraction wells
• Fiberoptic wells and electric field measurement wells
• Vapor barrier
• Vapor collection system
• Vapor treatment system
• Instrumentation
• Electrical
Equipment cost estimates are based on vendor quotes, estimates by B&RE or information
provided by Plant Design and Economics for Chemical Engineers [1]. When necessary, the Chemical
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Engineering Cost Index [3] is used to estimate current costs from earlier cost data. The annualized cost
(rather than depreciation) is used to calculate the annual equipment costs incurred by a site. The
annualized cost is calculated using the following formula:
where:
A = annualized cost, $
P = present value principal sum, $
i = interest rate, %
n = years
The value "n " is the useful life of the RFH unit and equipment(n = 10). It is assumed that a 1-year loan
at 8.5 percent interest has been secured to cover the cost of the equipment. The annualized equipment
cost prorated to the actual time the unit is at the remedial site (including assembly, shakedown and
testing, treatment, and disassembly) is $332,268 over a period of 76 weeks (1.46 years). The unit is
assumed to have no salvage value.
The list prices of the RF generator and tuners are estimated to be $836,000. The prices for the
antennae and extraction wells were determined from a standard engineering reference [2] and are
estimated to be $168,449 and $7,618, respectively. The developer states that full-scale commercial
systems would utilize less-expensive temperature measuring instruments, such as thermocouples.
Consequently, the use of thermocouples has been assumed for this estimate. Thermocouple well prices
were based upon information from instrument and plastics catalogs [4] [5] and are estimated to be
$11,081.
The price of the vapor barrier system, as provided by a silicon rubber sheet manufacturer, is
estimated to be $392. This process requires two vapor collection systems, the prices of which are
estimated to be $4,704 each, based upon prices obtained from a parts catalog [6]. The process also
requires a vapor treatment system; however, the system is considered to be a site-specific cost since it
is dependent on the contaminants present and local regulations. Therefore, the cost for the vapor
treatment system is not included in this cost estimate. Instrumentation for the system is assumed to be
13 percent of the purchased equipment cost and estimated to be $174,394 for the project [2] Electrical
costs are assumed to be 10 percent of the purchased equipment cost and estimated to be $134,149 for the
project
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Freight costs are assumed to be 6 percent of the total equipment purchase cost and estimated to
be $80,489 for the project [2]. Sales taxes are assumed to be 5.5 percent of the total equipment purchase
cost and estimated to be $73,782 for the project. When these costs are added to the total equipment
purchase cost, the overall equipment cost is estimated to be $1,341,490.
334 Startup and Fixed
Transportation activities include moving the KAIRFH system to the site. Travel costs for
equipment are covered under the freight charge applied to the total equipment purchase cost discussed
in Subsection 3.3.3.
Assembly consists of unloading the system from the trailer and assembling it at the site. It is
assumed that one fork lift truck at $325 per hour and one operator at $25 per hour will be required.The
cost to transport the fork lift truck to and from the site is $55 per hour, and it is assumed that it will take
4 hours to drop off and pick up the forklift. The total assembly cost is estimated to be $1,545.
It is estimated that 3 weeks will be required to set up equipment onsite, install antennae,
extraction wells, and thermocouples, and 1 week to assemble the above-ground components of the system.
Assembly and shakedown and testing are assumed to require five workers (two junior electricians, one
senior electrician, one technician, and one project manager). The assembly will consist of two 2-person
crews for 12 hours per day each; two-man crews were chosen since it is common practice at Superfund
sites to enact the "buddy system." The first shift will consist of a junior electrician and the technician,
and the second shift will consist of a junior electrician and the senior electrician. It is estimated the
project manager will spend 50 percent of his or her time on the project during assembly. Workers are
assumed to be local or will maintain residence near the site and will not be paid for travel or living
expenses. However, to compensate for the lack of living expenses, each worker's salary was increased
by a factor of 1.33. A multiplier of 1.8 was used for each of the worker's salaries to cover benefits and
other overhead costs. The estimated labor cost for assembly is $91,413. Listed below are the fully-
burdened costs (including wages, benefits, overhead, and profit) for all onsite personnel involved with
assembly and all other phases of the project.
• Junior Electrician — $99,000/year
• Senior Electrician — $135,000/year
. Technician - $108,000/year
• Project Manager — $162,000/year
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Working capital consists of the costs of borrowing capital for supplies, utilities, spare parts, and
labor necessary to keep the RFH system operating without interruption due to financial constraints [2].
The working capital for this system is based on maintaining 2 months of payroll for labor, 2 months of
payroll for the drilling subcontractor, and 1 month of inventory of the other items. For the calculation
of working capital, 1 month is defined as one-twelfth of 1 year. The estimated required working capital
is $103,043. The working capital cost at 8.5 percent interest for the time the equipment is onsite is
$13,590. Therefore, the total working capital cost is $116,633.
Insurance is assumed to be 2 percent of the fixed capital investment and estimated to be $33,752
per year and $54,660 for the project. Property taxes are assumed to be 3 percent of the total fixed capital
investment [5] and are estimated to be $50,628 per year and $81,990 for the project.
The cost for the initiation of process monitoring programs has not been included in this estimate.
Depending on the site, local authorities may impose specific guidelines for monitoring programs. The
stringency and frequency of monitoring requirements may have a significant impact on the project costs.
Air monitoring is likely to be required due to the potential release of air emissions during treatment.
A contingency cost is included to cover additional costs caused by unforeseen or unpredictable
events, such as strikes, storms, floods, and price variations [2]. The project contingency cost is estimated
to be 10 percent of the fixed capital investment. The annual contingency cost is $168,851 for a cost of
$184,579 to the project.
3.3.5 Operating Costs for Treatment
Treatment operations for the RFH system will be conducted 24 hours per day, 7 days per week
for 51 weeks. It is assumed that energy will be applied to each cell for a total of 6 weeks (same duration
that energy was applied during the SITE demonstration). It is estimated that it will take 3 weeks for each
cell to cool down. However, the time required to cool down will only add 3 weeks to the total time
onsite for the last cell, since all of the duplicated components can be removed during cool-down. It is
also assumed that it will take one week to move from one cell to the next. Labor costs consist of fully-
burdened personnel costs for five workers. Fully-burdened personnel costs are provided in Subsection
3.3.4. The treatment labor force will be structured as described in Section 3.3.4. The total labor cost
for treatment is estimated to be $732,302.
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It will be necessary to subcontract a drilling company for the installation and removal of the
electrodes and thermowells. A two-person crew will operate the drill rig. Boreholes for extraction wells,
antennae, electric field wells, and thermowells are assumed to be drilled to a depth of 20 feet. The cost
for drilling a 10-inch-diameter hole with a hollow stem auger is assumed to be $18 per foot. The
estimated costs for installing and removing the extraction wells and antennae are $6.50 and $2.50 per
foot, respectively. The total drilling costs for the project are estimated to be $1,161,020.
3.3.6 Supplies
For this project, supplies consist of spare parts and bentonite for backfilling the boreholes after
the extraction wells and antennae are installed. Annual spare parts costs are estimated to be 5 percent
of the fixed capital investment [2], which is approximately $84,379 per year and $122,986 for the entire
project,
Bentonite used to backfill the boreholes after the extraction wells and antennae are installed is
assumed to cost $12 per bag with each bag containing 50 pounds of bentonite chips. It is estimated that
13,744 bags of bentonite will be required for the project at atotal cost of $164,394.
3.3.7 Consumables
Electricity is required not only during the heating of the cell but also during its cool-down period.
The average hourly power usage rates during the heating and cool-down periods are estimated to be 484.5
kW and 84.5 kW, respectively. Based on a 6-week duration for heating a cell and 3-week duration for
a cooling period for each cell, the total electricity cost for the project is approximately $327,074 (at a rate
of $0.077 kWh).
In order to implement the KAI RFH technology, the site must have a supply of uncontaminated
water available. Water will be used for decontamination of the drill rig augers and be added to the
bentonite used in backfilling the boreholes and is estimated to be 600 gallons per day. A sewerage charge
is also assumed for all water used even if it is not discharged to the sewer. Based upon rates provided
by the Cincinnati Water Works, the total water and sewerage bill for the project is estimated to be $985.
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3.3.8 Effluent Treatment and Disposal
Steam and vaporized contaminants will be given off during treatment using the RFH system.
Entrained liquid may also be present in the effluent stream. This vapor stream should be the only effluent
from the system. A vapor treatment system may be operated in series with the RFH system. The design
of this vapor treatment system will vary depending on the contaminants present in the soil. Therefore,
for the purposes of this report, this site-specific cost is assumed to be the obligation of the site owner or
responsible party and is not included in this analysis.
3.3.9 Residuals and Waste Shipping, Handling, and Transport
If the treatment area extends below the natural water table, it will be necessary to install
dewatering wells to lower the water table. The groundwater pumped out of these dewatering wells is
likely be contaminated. However, because dewatering will only be required at some sites and because
the quantity of groundwater removed and the contaminants present in the groundwater will vary from site
to site, this site-specific cost is assumed to be the obligation of the site owner or responsible party and
thus is not included in this estimate.
Several boreholes will be drilled for installation of the extraction wells and antennae. The soil
cuttings removed from these boreholes will be contaminated and will require treatment. During the
demonstration, these cuttings were drummed for later disposal For this cost estimate, it is assumed that
the cuttings will be placed on top of the soil surface and treated along with the undisturbed soil. If the
cuttings are not treated along with the undisturbed soil, they will be a contaminated residual. The
residual treatment cost is also assumed to be the obligation of the site owner or responsible party and is
not included in this estimate.
3.3.10 Analytical Services
No analytical costs are included in this cost estimate. The responsible party may elect or may
be required by local authorities to initiate a sampling and analytical program at its own expense. If
specific sampling and monitoring criteria are imposed by local authorities, these analytical requirements
may contribute significantly to the cost of the project.
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3.3.11 Facility Modification, Repair, and Replacement
Maintenance costs vary with the nature of the waste and the performance of the equipment and
include costs for design adjustments, facility modifications, and equipment replacements. For estimating
purposes, annualized maintenance costs (excluding labor) are assumed to be 3 percent of the fixed capital
investment [2] and are estimated to be $50,655 per year and $55,374 for the project.
3.3.12 Site Demobilization
It is assumed that the transportation costs in the demobilization phase will be equal to the
transportation costs of the assembly phase of the project. Therefore, the cost for site demobilization is
estimated to be $10,820. It is assumed that 1 week will be required for disassembly of the above-ground
components and 1 week will be required for preparation time needed to remove the equipment from the
site. Labor will be structured as described in Subsection 3.3.4 and will cost approximately $159,775.
3.4 RESULTS OF ECONOMIC ANALYSIS
This subsection summarizes the results of the economic analysis of the KAIRFH system treating
10,940 tons of soil based upon the developer's claim that the RFH system is capable of operating with
an on-line factor of 95 percent on a full-scale level. The on-line factor is used to adjust the unit treatment
cost to compensate for the fact that the system is not on-line constantly because of maintenance
requirements, breakdowns, and unforeseeable delays, and considers costs incurred while the system is
not operating.
Table 4 summarizes the estimated treatment costs per ton using the KAI RFH system in the
treatment of 10,940 tons of soil with an on-line percentage of 95 percent. Table 4 also presents the
treatment costs of the 12 cost categories as a percentage of the total cost. It is important to remember
that the five cost categories not included in this analysis may significantly add to the unit cost. These
costs are considered order-of-magnitude estimates as defined by the American Association of Cost
Engineers. The actual cost based upon EPA's evaluation is expected to fall between 70 and 150 percent
of the estimated cost. The vendor claims the cost may be as low as 50 percent of the cost indicated in
Table 4.
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Table 4. Treatment Costs for the KAI RFH System Treating 10,940 Tons of Soil with a
95 Percent On-line Time
Item
Site preparation
Permitting and regulatory
Equipment
Startup and fixed
Operating costs for treatment
Supplies
Consumables
Effluent treatment and disposal
Residuals and waste shipping, handling,
and transport
Analytical
Facility modification, repair, and
replacement
Site demobilization
Total operating costs
Cost (S/ton)
NE
NE
30.37
54.13
173.06
26.32
30.02
NE
N-E
NE
6.74
15.59
336.24"
Cost (as a 96 of total cost)
NE
NE
9.0
16.1
51.5
7.8
8.9
NE
NE
NE
2.0
4.6
100b
a Approximately $50 per ton of the total cost is attributed to the SVE system.
b The SVE system is approximately 15% of the total cost.
NE = Not estimated in the analysis. The cost for this item is highly dependent on site-specific factors.
Table 4 indicates that the RFH system will cost approximately $336 per ton to remediate the
10,940-ton site. Table 4 also illustrates that startup and fixed and operating costs for treatment
contributed the most to the unit cost, and labor is approximately 27 percent of the total cost. SAIC
estimates that the SVE system is responsible for approximately $50 per ton of the treatment costs (15%
of the total cost)[7].
3.5 REFERENCES
1. Evans, G.M. Estimating Innovative Technology Costs for the SITE Program. Journal of the Air
and Waste Management Association, Vol. 40, No. 7, July 1990. pp. 1047-1051.
2. Peters, M.S. and K.D. Timmerhaus. Plant Design and Economics for Chemical Engineers,
Third Edition. McGraw-Hill, Inc., New York, 1980.
3. Chemical Engineering. McGraw-Hill, Inc. Volume 101, Number 11, November 1994.
4. Cole-Parmer 1995-1996 Catalog. Niles, Illinois.
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5. Consolidated Plastics Catalog. Twinsburg, Ohio, 1994.
6. Grainger Industrial and Commercial Equipment and Supplies 1994 General Catalog.
Lincolnshire, Illinois, 1994.
7. U.S. Environmental Protection Agency In Situ Soil Vapor Extraction Treatment Engineering
Bulletin. EPA/540/2- 91/006, February 1991.
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SECTION 4
TREATMENT EFFECTIVENESS
4.1 BACKGROUND
The SITE demonstration of KAFs RFH system took place at Site S-l at Kelly APB near San
Antonio, Texas (see Figure 2). From 1960 to 1973, Site S-l was used as an intermediate storage area
for wastes awaiting offsite reclamation. Waste liquids including mixed solvents, carbon cleaning
compounds, petroleum oils, and lubricants were temporarily stored in tanks located within this area.
Spills during waste transfer operations and flooding of storage tanks are reported to have caused the
current soil contamination. Much of the spilled waste accumulated in a long sausage-shaped "sump,"
which was the lowest portion of a depression on the eastern side of the site. After waste transfer
operations at the site were halted, the tanks were removed, the sump and depression were backfilled, and
the area was graded. Soil contamination persists down to the saturation zone, which begins
approximately 25 to 30 feet below the surface.
Figure 3 shows the locations of the depression and the sausage-shaped sump. The SITE
demonstration was conducted in the southern end of the sump, where preliminary sampling indicated that
contaminant concentrations were highest. The original treatment zone, as specified in the Demonstration
Plan, was 10 feet wide, 15 feet long, and 20 feet deep. The original plan specified that the lo-foot
applicators would be moved up and down in their liners, applying heat from 0 to 20 feet below ground
surface (bgs). However, before the RF'H system was turned on, B&RE and KAI made the decision to
apply heat to only half of the original treatment zone. The "revised treatment zone" is 10 feet wide and
15 feet long but only extends from 4 to 14 feet bgs. The depth was reduced because the applicators
remained stationary in their liners. All of these modifications were made based on timing and funding
limitations placed on the project just prior to startup. The SITE Program was not informed of any of
these changes until after sampling was completed; therefore, no changes to the Demonstration Plan were
made.
36
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. Growden Dr.
W. Thompson
Figure 2. Regional maps showing demonstration location.
37
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N
Approximate limit of
former sump area
Approximate limit of
former depression area
feel
Site
Boundary
•x—N—x- Fence
50
100
150
Figure 3. Plan view of demonstration site.
During the demonstration, power was supplied alternately to the two antennae, Al and A2.
Power was applied to A2 for 28.9 days, then switched to Al. After the Al heating commenced, a high
voltage discharge occurred within the transmission line near it. The center conductor heated beyond the
system's thermal expansion capability and shorted Al, so power was only applied to Al for 8.2 days.
Heating was switched back to A2 for the final 12.9 days. This malfunction caused the soil
surrounding the Al liner to be heated to a significantly lesser degree than the soil surrounding the A2
liner.
The primary objective of the SITE Program demonstration was to evaluate the ability of theRFH
system and associated SVE system to remove TRPH from the soil. In addition to the SITE Program's
primary objective, the following secondary objectives were developed:
1. Evaluate the removal of VOCs feasible under the conditions of the test. Target VOCs are
listed in Table 5.
38
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2. Evaluate the removal of SVOCs feasible under the conditions of the test. Target SVOCs are
listed in Tables 6 and 7.
3. Determine the outward migration, if any, of contaminants into a zone outside the treatment
area.
4. Characterize the soil being treated by determining particle size distribution.
After a review of data from another RFH demonstration conducted at the same site, the following
additional secondary objectives were added as part of the demonstration:
1. Characterize the vapors extracted by the SVE system by collecting vapor samples at six key
times before, during, and after the operation of the RFH system.
2. Characterize the soil vapor at the site by collecting soil gas samples before treating the soil.
3. Characterize the groundwater at the site and identify if the groundwater could be a potential
source of contaminant migration into the treatment zones by collecting groundwater samples
from existing wells.
Table 5. Target VOCs
Acetone
Bromoform
Carbon disulfide
Chlorodibromomethane
chloroform
1,2-Dichloroethane
1,2-Dichloropropane
Ethylbenzene
4-Methyl-2-pentanone (MIBK)
Tetrachloroethene
1,1,2-Trichloroethane
Vinyl chloride
Benzene
Bromomethane
Carbon tetrachloride
Chloroethane
Chloromethane
1,1-Dichloroethene
cis-l,3-Dichloropropane
2-Hexanone
Styrene
Toluene
Trichloroethene
Xylenes, total
Bromodichlorobenzene
2-Butanone
Chlorobenzene
2-Chloroethyl vinyl ether
1,1-Dichloroethane
trans-l,2-Dichloroethene
trans-l,3-Dichloropropene
Methylene chloride
1,1,2,2-Tetrachloroethane
1,1,1-Trichloroethane
Vinyl acetate
39
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Table 6. Target SVOCs (Acid Extractables)
Benzoic acid
2,4-Dichlorophenol
2,4 -Dinitropheno 1
2-Nitrophenol
Phenol
4-Chloro-3 -methylphenol
2,4-Dimethylphenol
2-Methylphenol
4-Nitrophenol
2,4,5 -Trichlorophenol
2-Chlorophenol
4,6-Dinitro-2-methylphenol
4-Methylphenol
Pentachlorophenol
2,4,6-Trichlorophenol
Table 7. Target SVOCs (Base/Neutral Extractables)
Acenaphthene
Benzo(a)anthracene
Benzo(ghi)perylene
bis(2-Chloroethoxy)methane
bis(2-Ethylhexyl)phthalate
4-Chloroaniline
Chrysene
Di-n-butylphthalate
1,4-Dichlorobenzene
Dimethylphthalate
Di-n-octyl phthalate
Hexachlorobenzene
Hexachloroethane
2-Methylnaphthalene
3-Nitroaniline
n-Nitrosodiphenylamine
Pyrene
Acenaphthylene
B enzo (b) fluoranthene
Benzo(a)pyrene
bis(2-Chloroethyl)ether
4-Bromophenyl phenyl ether
2Chloro naphthalene
Dibenz(a,h)anthracene
1,2-Dichlorobenzene
3,3' -Dichlorobenzidine
2,4-Dinitrotoluene
Fluoranthene
Hexachlorobutadiene
Indeno( l,2,3-cd)pyrene
Naphthalene
4-Nitroaniline
n-Nitrosodipropylamine
1,2,4-Trichlorobenzene
Anthracene
B enzo (k) fluoranthene
Benzyl alcohol
bis(2-Chloroisopropyl)ether
Butyl benzyl phthalate
4-Chlorophenyl phenyl ether
Dibenzofuran
1,3 -Dichlorobenzene
Diethylphthalate
2,6-Dinitrotoluene
Fluorene
Hexachlorocyclopentadiene
Isophorone
2-Nitroaniline
Nitrobenzene
Phenanthrene
The first step of the data evaluation process was to determine which contaminants were present
in a sufficient number of pretreatment samples at sufficient concentrations to warrant a statistical
evaluation. Many analytical method-specific VOCs and SVOCs were not detected in any pretreatment
samples. The process used to select contaminants for the statistical evaluation is described in Appendix
A.
40
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Changes in concentrations were determined for each compound by comparing analytical data
generated from soil samples taken before and after the RFH treatment. Initial and final soil samples were
taken from "matched" boreholes (i.e., final boreholes were placed as close as possible to the original
boreholes and samples were collected from the same depth). Initial and final contaminant concentrations
were compared to determine a concentration change for each matched pair. Concentration changes for
all matched pairs within a specified zone were used to calculate the geometric mean concentration change
for that zone (the geometric mean was used because it was determined that TRPH concentrations were
log-normally distributed). The matched pairs of initial and final contaminant concentrations were
analyzed using a paired t test, which determined whether the geometric mean concentration change within
a specific zone was statistically significant. A description and application of the paired t test is presented
in Appendix A.
B&RE also evaluated KAFs RFH system in terms of operational features such as performance
of the vapor barrier, performance of the vapor collection system, amount of heat lost to the soil
surrounding the treatment zone, and measurement of RF fields radiated from the test array. Because
these operational features are not central to the SITE demonstration, data collected by B&RE are not
presented in Appendix A.
4.2 METHODOLOGY
4.2.1 Soil
Pretreatment soil sampling was conducted concurrent with the installation of the subsurface
components. A mobile, hollow-stem auger drill rig was used to drill the boreholes required for the
installation of the subsurface components. Figure 1 shows the locations of all subsurface components.
The drill rig was also used to drive a split spoon into the boreholes wherever a soil sample was needed.
Sampling procedures are described in greater detail in following paragraphs.
The Demonstration Plan specified the collection of samples for TRPH, VOC, and SVOC analyses
at the depths and locations shown in Figure 4. Pretreatment soil samples were generally collected at the
designated depths, but in a few cases, insufficient soil was recovered in the split spoon at the specified
depth. When insufficient recovery was obtained, the next deeper interval was sampled instead. Samples
were labeled with ID numbers that identified their locations (borehole and sampling interval).
41
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4*
to
>:
x
El A1 Ei
F1 E4 F4 E2
F3 E? F2 E5 F5 E3 A2 E8 TD3 TO8 TO6
has
for TRPH
has
for TRPH, VOC,
SVOC
fx| = THPH
., ^ TRPH
' for
and
4
42
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RFH began on April 24, 1994 and ended on June 7, 1994. Electrical power supply problems
experienced at the beginning of the heating period reduced the amount of RF energy applied to the soil.
The vapor collection system was operated from April 13, 1994 until June 24, 1994 to enhance the
removal of contaminant vapors. The soil was then allowed to cool undisturbed until July 7, 1994, when
final sampling began. The above-ground components of the system were disassembled and removed prior
to final sampling. Subsurface components were removed following final sampling.
Post-treatment boreholes were placed within 2 feet of the corresponding pretreatment boreholes.
An attempt was made to obtain all post-treatment samples from the same depth as the corresponding
pretreatment sample, but insufficient material was collected from one sampling point, and it was
necessary to collect that sample 2 feet deeper than planned. All other post-treatment samples were
collected at approximately the same depths as the corresponding pretreatment samples.
Soil samples were collected using 3-inch-diameter split spoons. The split spoon was pushed or
hammered into the soil (at the appropriate location and depth) using the drill rig. The split spoon was
then removed from the borehole and placed on a flat surface covered with clean aluminum foil. The main
portion of each split spoon was 2.0 or 2.5 feet long and contained four or five 6-inch-long stainless steel
liners, which were numbered from bottom to top. The bottom portion of the split spoon, which was
approximately 3 inches long and was called the "shoe," did not contain any liners.
The soil characteristics at each sampling point affected the number of liners that were filled with
soil. The split spoon filled from the bottom: first the shoe filled, then the first liner, then the second
liner, and so on. For example, if the split spoon was pushed into the soil 12 inches, and then hit a large
rock that stopped its progress, only the shoe and the first liner would have been filled with soil. The
second liner would have been partially filled with soil. For each given sampling point, one to four liners
were filled with soil.
Soil samples were collected for both chemical and particle size analyses. When a soil sample was
selected for chemical analyses, the field sampling crew did not remove it from the stainless steel liner in
which it was collected. The ends of the liner were securely covered with Teflon sheets and polyethylene
caps. The liner was labeled, sealed in a plastic bag, and placed in a cooler with ice for preservation.
When a soil sample was selected for particle size analysis, the field sampling crew removed the sample
from its liner and placed it in a plastic jar or a plastic bag. When rocks were present in the sample, extra
43
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material (from the shoe or from other liners) was frequently added to the particle size sample, since larger
quantities of material are required for particle size analyses of soils containing large particles. Samples
selected for particle size analyses did not require preservation.
When the split-spoon was filled or nearly filled (i.e., three or four liners were full of soil) the
second liner was selected for chemical analysis. The third liner was generally selected for particle size
analysis. When a chemical analysis field duplicate was collected, the third liner was then used as the
chemical analysis field duplicate and the first liner was the particle size sample. When a particle size
analysis field duplicate was collected, the first and third liners were the particle size duplicate and sample.
When field duplicates for both chemical and particle size analyses were collected from the same split
spoon, the second liner was the sample for chemical analysis, the third liner was then used as the field
duplicate for chemical analysis, and the first and fourth liners were the particle size sample and duplicate.
When only two liners were full of soil, the second liner was selected for chemical analyses.
When a chemical analyses field duplicate was collected, the first liner was selected as the chemical
analyses field duplicate, and material from the shoe and any material from the third liner was selected
for particle size analysis. When the sampling location was not designated for the collection of a field
duplicate for chemical analyses, the first liner was selected as the particle size sample.
When only the first liner was full of soil, it was selected for chemical analyses. Material from
the shoe and any material in the second liner was selected for particle size analysis. No field duplicates
were collected if only the first liner was full.
Samples, blanks, and QA/QC samples were collected and prepared for chemical analyses. The
samples and blanks described in this paragraph were prepared during each phase of sampling
(pretreatment and post-treatment). For each phase of sampling, 64 samples were analyzed for TRPH and
moisture; 32 of those samples were also analyzed for VOCs and SVOCs. Within the original treatment
zone, 40 samples were analyzed for TRPH and moisture; 20 of these samples were also analyzed for
VOCs and SVOCs. Within the revised treatment zone, 20 samples were analyzed for TRPH and
moisture; 7 of these samples were also analyzed for VOCs and SVOCs.
44
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Also during each phase of sampling, six field duplicates were collected for TRPH and moisture;
three of those field duplicates were also analyzed for VOCs and SVOCs. Five laboratory duplicates were
prepared for moisture during the pretreatment sample analysis and four during the post-treatment
analyses. Four laboratory duplicates were prepared for TRPH during each phase of testing. Samples
were analyzed for VOCs, SVOCs, and TRPH as matrix spike/matrix spike duplicate (MS/MSD) samples
at the frequencies specified in Table 8. Three field blanks were analyzed for VOCs, SVOCs, and TRPH.
Each cooler used to ship samples for VOC analyses contained a trip blank, which was analyzed for
VOCs.
Additional samples were collected for particle size analysis. During pretreatment sampling, 58
samples and 5 field duplicates were submitted for particle size analysis. During post-treatment sampling,
52 samples and 6 field duplicates were submitted for particle size analysis. One particle size analysis
laboratory duplicate was prepared for each phase of sampling. The numbers and types of samples
analyzed for theKAI RFH SITE demonstration are summarized in Table 8.
Table 8. Summary of Number of Samples Analyzed for the KAI RFH Test
Measurement
Pretreatment
TRPH
Moisture
Particle Size
Distribution
VOCs
SVOCs
Post-treatment
TRPH
Moisture
Particle Size
Distribution
VOCs
SVOCs
Number
of
Samples
64
64
58
32
32
64
64
52
32
32
Field
Duplicates
6
6
5
3
3
6
6
6
3
3
Laboratory
Duplicates
4
5
1
NA
NA
4
4
1
NA
NA
Matrix
Spikes
7
NA
NA
5
4
5
NA
NA
5
3
Matrix
Spike
Duplicates
7
NA
NA
5
4
5
NA
NA
5
3
Field
Blanks
3
3
NA
3
3
3
3
NA
3
3
Trip
Blanks
NA
NA
NA
10
NA
NA
NA
NA
6
NA
Total
91
78
64
58
46
87
77
57
54
44
NA = not applicable
45
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422 SVE Vapor Stream
The SVE system was designed with eight extraction wells. Six of the eight wells (El, E3, E4,
E5, E6, E8) were screened 10 to 20 feet bgs, which is almost entirely below the revised treatment zone
of 4 to 14 feet bgs. The other two (E2 and E7) were screened from 0 to 10 feet bgs, which covered all
but the last 4 feet in the revised treatment zone. Throughout the demonstration, the SVE system operated
using various combinations of extraction wells. At least one extraction well was operating at any given
time, and as many as four were used simultaneously. Wells that were not being used at a particular time
were capped, with the exception of several days when some wells were open to the atmosphere (i.e.,
operated in the passive mode). Operating data on the SVE system is presented in Appendix A.
The vapor stream from the SVE system was sampled and analyzed six times during the
demonstration. Vapor stream samples were collected from a combined header exhaust port downstream
of where the individual extraction wells were tied in. The VOC samples were collected in SUMMA
polished stainless steel canisters and analyzed using a gas chromatograph (GC) with dual columns and
multiple detectors (GC/MD). The SVOC samples were collected using a modified version of EPA
Method 0010 and analyzed using Method 8270. These samples were collected to characterize the
compounds being removed from the subsurface during system operation.
423 Soil Vapor
Six soil vapor samples were collected and analyzed from the existing pressure transducer wells
positioned near the treatment area (TD1, TD2, TD3, TD6, TD7, TD8). TD1 and TD2 are deep wells
screened from approximately 20 to 24 feet. The others are shallow wells screened from about 10 to 14
feet. The samples were collected in SUMMA polished stainless steel canisters and analyzed for VOCs
using GC/MD These samples were collected prior to the start of RFH and were used to determine what
VOCs may have been present in the soil vapor prior to heating. This data is presented in Appendix A.
4.2.4 Groundwater
Groundwater samples were collected from three wells near the treatment zone (MW-10, MW-09,
andDW-02) during drilling activities. Three well volumes were purged from each well before the sample
was collected. Groundwater samples were analyzed for the same compounds as the soil samples (TRPH,
the target VOCs in Table 5, and the target SVOCs in Tables 6 and 7). Data from these samples were
used to characterize the groundwater and to identify whether the groundwater was a potential source for
46
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into 'the soil
4.3
It is to note that
not under the control of the developer. These factors with the delivery of AC
power to the RFH system, the and of extraction wells, and the of time
to the soil. Commercial of the RFH technology with factors
control of the developer may yield significantly results.
4,3.1 Soil
Soil were and the soil KAFs RFH technology. As
discussed in Subsection 4.2,1, the post-treatment soil were as close as possible to the
sampling locations. The analytical were as of pre- and post-
samples. If concentrations had only the percent decrease would
for pair. Howe¥er, in were higher
concentrations. As a result, for contaminant, the log-transformed ratio of the post-
concentration to the pretreatment concentration was calculated for each sample pair. The ratios
were evaluated statistically a t test to the concentration had exhibited
a statistically significant change (starting at the 80 level) the pre- and post-
sampling events. The ratio of post-treatment concentration, to pretreatment
concentration was also calculated. This geometric ratio was converted to a geometric mean percent
or a geometric as
4.3,1.1
The soil were by EPA 907!A [2] prior to TRPH analysis by EPA
Method 4(8.1 [3], Samples were also for moisture by ASTM D2216, The
TRPH sesults were then adjusted, to a dry-weight basis. TRPH. concentrations exhibited statistically
significant changes at the 95 90 percent confidence levels within the revised treatment zone and,
original treatment zone, respectively. The geometric decreases were 49 percent within
'the zone and 29 percent within the zone. Data from pre- and post-
TRPH are In Appendix A.
47
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TRPH removals were not as projected. A number of problems with the design and operation of
the SVE system were identified after the demonstration was complete. These problems included
extraction wells screened below the revised treatment zone, which may have drawn contaminants from
the revised treatment zone into the cooler soil, where they condensed. The SVE system configuration also
may have resulted in low vapor flows within the treatment zone and in high vapor flows from areas
outside the treatment zone. These problems may have resulted in contaminant migration into the
treatment zone from surrounding soils. In addition, temperature sensors indicated that only a portion of
the revised treatment zone reached the revised target temperature range of 100 to 130°C. The developer
claims that the actual soil temperatures were higher than the recorded values since measurements were
taken within boreholes. This is due to there being no sensors that measured the instantaneous,
microscopic heating of the contaminants, and all sensors were likely to provide readings that were lower
than the actual temperatures of materials.
Because of changes in the RFH system prior to startup and the design of the SVE system, it
cannot be concluded whether the changes in TRPH concentration inside and outside the treatment zones
were a result of RFH treatment or were due solely to application of SVE.
As discussed in Subsection 4.1, significantly more power was applied to A2 than Al during the
demonstration. Because Al and A2 were heated differently, Al and A2 zones were evaluated
individually in addition to the evaluations of the original and revised zones. Like the revised zone, the
Al and A2 zones both extend from 4 to 14 feet bgs. Because the RFH system heats soil radially, the Al
and A2 zones were elliptically shaped and centered around each antenna. The Al zone, comprising 15
samples, contains the following boreholes: El, E6, Fl, Al, F4, E4, E2, F3, E7, and E5. The A2 zone,
comprising 15 samples, contains the following boreholes: E2, F3, E7, ES, F2, A2, F5, E3, E8, and E4.
(See Figure 1 for borehole locations.) The Al zone did not exhibit a change in contaminant concentration
that was statistically significant (at the 80 percent confidence level). The A2 zone exhibited a statistically
significant change at the 80 percent confidence level. The estimated geometric mean decrease was 44
percent. Because only a portion of the revised treatment zone reached the target temperature range of
100 to 130°C, it seems most likely that the system did not achieve an adequate temperature. The low
temperatures were at least partially due to problems with the electrical power available at the site.
48
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4.3.1.2 SVOCs and VOCs
SVOCs and VOCs were designated as noncritical measurements for this demonstration because
samples collected prior to the demonstration indicated that the soil at the site generally contained low
concentrations of SVOCs and VOCs SVOCs and VOCs were designated as noncritical measurements
in the Demonstration Plan and therefore their concentrations were measured in only half of the soil
samples. SVOC samples were extracted by EPA Method 3540 [2] prior to analysis by EPA Method 8270
[2]. VOC concentrations were determined using EPA Method 8240 [2]. SVOC and VOC results are
presented on a dry-weight basis.
Concentrations of individual SVOCs and VOCs in the soil samples were evaluated using the same
procedures described for TRPH. Concentrations of several SVOCs exhibited statistically significant
changes (at an 80 percent confidence level) within the original and revised treatment zones. Statistically
significant changes in SVOC concentrations within the original and revised treatment zones are presented
in Table 9. As with the TRPH data, it cannot be concluded that the changes in SVOC concentrations
inside and outside the treatment zones were affected byRFH treatment.
Table 9. Summary of SVOC Decreases Inside Treatment Zones
Geometric Mean Percent Decrease Geometric Mean Percent Decrease
contaminant in Original Treatment Zone in Revised Treatment Zone
Benzo(b)fluoranthene 44* 40b
Benzo(a)pyrene 44C 43b
Bis(2-ethylhexyl)phthalate 55d ***
Chrysene
***
Pyrene
Fluoranthene
40"
60*
53b
*** No statistically significant change at the 80 percent confidence level.
a Change accepted at a 97.5% confidence level.
b Change accepted at a 80% confidence level.
c Change accepted at a 95% confidence level.
d Change accepted at a 90% confidence level.
Pre- and post-treatment concentrations of individual VOCs were also measured. None of the
individual VOCs exhibited statistically significant changes (at an 80 percent confidence level) within the
original or revised treatment zones. High concentrations of some VOCs (toluene, chlorobenzene,
-------
methylene chloride) were detected in some soil samples, but the changes in concentrations were not
statistically significant. However most target VOCs in the pre- and post-treatment soil samples had low
concentrations, and a statistical evaluation could not be made. No conclusions about changes in VOC
concentrations can be made.
Due to fewer data points (as compared to amount of TRPH points), and since the analysis of
SVOCs and VOCs was not a critical parameter, contaminant changes were not examined in the Al and
A2 zones
4.3.1.3 Particle Size Distribution
Laboratory tests were conducted to determine sample grain size distribution. The full procedure
as described in ASTM D422 [2] was used for at least 10 percent of the samples. Samples that were
processed in accordance with the ASTM procedure as prescribed are referred to as wet-sieved samples.
The remaining samples were analyzed by dry-sieving. Regardless of which procedure was used to
perform the grain size distribution, the soils were first prepared according to ASTM Method D421. In
this method, the soils are dried and processed to break down all soil particles into their component sizes.
Samples processed by dry-sieving were simply taken from this sample preparation procedure and screened
using twelve sieve sixes, ranging from 3 inches (7.62 cm) to 75 /xm (#200 sieve). For the samples
processed by wet-sieving, the dried soil sample is initially segregated into two fractions using a #10 sieve.
Soils that pass through the #10 sieve are then dispersed in an aqueous solution and passed over the
remaining sieves "wet. " Particles that pass the #200 sieve are further classified using a hydrometer,
which results in a minimum size classification of approximately 0.001 mm. To provide information
required for the reduction of the hydrometer data, the specific gravity of the soils subjected to wet-sieving
was determined using the procedure outlined in ASTM D854-83 [1].
This combined use of dry- and wet-sieving was specified in the Demonstration Plan because
discussions with laboratory personnel indicated that the two procedures should yield similar results for
particle sixes not passing the #200 sieve. This was not the case for the soil samples associated with this
site. The dry-sieve method produced results that overestimated the sand fraction of the soil. The soil
preparation method was apparently insufficient to break down clumps of cohesive clay particles. It was
known that wet-sieving and subsequent hydrometer testing would be required to characterize particles that
passed the #200 sieve further and, therefore, a decision was made to subject a subset of the entire sample
set to the wet-sieving procedure. Since dry-sieving is less costly, and the further characterization of these
50
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small particles was a minor point, it seemed reasonable to use dry-sieving primarily.
As a result, particle size distribution data obtained by wet-sieving is being used to characterize
the site, and the data obtained by dry-sieving are not being used. The particle size distribution summary
from wet-sieving tests is listed in Table 10. For evaluation purposes, the data were simplified into three
standard geologic categories: gravel, sand, and fines. Particles that are less than 3 inches in diameter
but will not pass through a #4 sieve (4.75 mm) are classified as gravel, particles that will pass through
a #4 sieve but will not pass through a #200 sieve are classified as sand, and particles that will pass
through a #200 sieve are classified as fines. Additional particle size distribution data are presented in
Appendix A.
Table 10. Average Particle Size Distribution (Wet-Sieving Only)
Pretreatment
Post-treatment
Average Percent Gravel
29.4
42.9
Average Percent Sand
30.7
29.1
Average Percent Fines
39.9
28.1
The data show a predominance of sand and gravel at this site, which indicates the soil should be
amenable to RFH and SVE.
4.3.2 SVE Vapor Stream
Appendix A lists the results of the vapor stream samples. Approximately 70 VOCs and 12
SVOCs were detected in these vapor samples, indicating that these contaminants were removed from the
soil. Typically, vapor stream concentrations from SVE systems are higher when the system is first
started, then decreases as the system continues to operate. Because RFH volatilizes the contaminants as
it operates, this type of pattern should not be observed. In fact, vapor stream concentrations may increase
as the soil temperature increases. In particular, if an area of high contaminant concentration is heated,
corresponding increases in the vapor stream concentrations are expected.
During the demonstration, numerous changes were made to the operation of the SVE system.
Over the course of the demonstration, the SVE system was operated using 55 different combinations of
operating parameters. Operating parameters that were varied included the number of wells being operated
51
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as extraction wells, the number of wells being operated as passive vent wells (if any), and the operating
pressure.
The first sample was collected when the SVE system was operational, but prior to the start of
the RFH system. Although the SVE system was not yet operating continuously, it was operating for this
sampling event. This sample established baseline conditions (i.e., removal with SVE only). Sample 2
was collected just after the RFH system was turned on. Sample 3 was collected when soil temperatures
were approximately 100°C near the operating antenna. (At 100°C, moisture in the soil should begin to
be driven off.) Sample 4 was collected when soil temperatures reached their maximum. Sample 5 was
collected several days after the RFH system was turned off, but while the SVE system continued to
operate. The sample represented the start of the cool-down phase. Sample 6 was collected just prior to
the shut-off of the SVE system.
In general, contaminant concentrations in the first and second vapor samples were almost equal
to one another. The third and fourth samples had lower contaminant concentrations than the first two
samples. The fifth sample had the lowest concentrations of the six samples, while the last sample had
the highest concentrations. These relative concentrations do not match the patterns that would be
expected for an SVE system or an SVE system used with an RFH system. However, because the
operation of the SVE system varied considerably throughout the demonstration (e.g., wells E4 and E5
were used for vapor extraction for the third and fourth sample, but not the fifth), it is not possible to
explain the observed vapor stream contaminant concentrations. The data indicate the SVE system is
removing contaminants; however, it is not possible to determine how RFH enhanced SVE performance.
4.3.3 Soil Vapor Gas
These samples were collected on the same day that the baseline sample for the SVE vapor stream
was collected (Sample 1). Appendix A lists the results of the soil vapor samples. The soil vapor data
appear similar to the vapor stream data from the SVE system (i.e., compounds detected in the soil vapor
were also detected in the SVE vapor stream). Because the SVE system operated under varying
conditions, no attempt was made to correlate these data sets.
-------
4.3.4 Groundwater Samples
Groundwater was sampled from three different wells just outside the treatment zone before it
received RFH. The results of this sampling are listed in Appendix A. The groundwater data, which are
considered noncritical, show concentrations of TRPH and several target VOCs and SVOCs. All of these
compounds were also detected in either the soil, soil vapor and/or the SVE vapor stream. No attempt
was made to correlate these data sets to each other. The approximate location of the wells is displayed
in Figure 5.
MW09
> N •
MW10
DW02
Original Treatment Zone
• Groundwater sample collection point
Figure 5. Locations of Groundwater Sample Collection
4.3.5 Moisture
Moisture analysis was conducted so that soil sample concentration results could be converted to
dry weight. Appendix A presents the results of moisture analyses.
4.4 CONTAMINANT MIGRATION
An RFH system generates a flow of contaminant vapors in the soil that must be collected with
an SVE system. A properly designed SVE system will collect the contaminant vapors and prevent the
inward flow of contamination into the treatment zone from the surrounding area. It will also prevent the
-------
outward migration of contaminants. In order to determine if migration is occurring, samples must be
collected and analyzed in the treatment zone and the surrounding area before and after RFH. Changes
in concentrations between samples inside the treatment zone would be compared to changes in
concentrations between samples outside the treatment zone.
In evaluating the soil data to determine if contaminant migration had occurred, a number of
problems with the SVE system were identified. A vapor barrier was installed to prevent air infiltration
and consequent short-circuiting at the surface and to prevent the escape of fugitive emissions. The vapor
barrier extended 10 feet laterally beyond the treatment zone boundaries on each of the four sides. With
the particular operational configurations of vacuum wells selected, the presence of the vapor barrier
resulted in low gas flows within much of the treatment area and in high flow rates from areas outside the
treatment zone. This may have resulted in contaminant migration into the treatment zone from
surrounding soils.
The original SVE system design called for three of the six surrounding wells (E6, E7, and E8)
to be passive vent wells; air would be extracted from one or more of the other wells. This design would
help to isolate the treatment zone, which would have minimized contaminant migration into it. However,
during the demonstration, the SVE system was generally operated with no passive vent wells and a
variety of different configurations of extraction wells. Wells not being used in any particular
configuration were capped. Normally, two or more extraction wells were operated at the same time.
With no passive vent wells, the soil gas flow rates would have been very low in the area bounded by the
vacuum wells because the gas pressure gradients in this region would have been quite small. This would
have been true even when the vacuum on the extraction wells was high. Since two or more extraction
wells were generally in operation at one time, and there were no passive vent wells, and also since the
area was covered by an impermeable cap, there would have been very little gas flow in most of the region
lying within the polygon having the vacuum wells at its comers.
The extraction wells were generally screened well below the revised treatment zone, so that
organics volatilized in the revised treatment zone may have condensed when drawn into the cooler
underlying soil.
TRPH concentrations increased outside the revised treatment zone at the 80 percent confidence
level. The estimated geometric mean increase was 39 percent. The increase is probably due to inward
-------
vertical and lateral migration from the surrounding area. TRPH increased outside the original treatment
zone at the 97.5 percent confidence level. The estimated geometric mean increase was 96 percent. This
increase was probably due to the design and operation of the SVE system, which resulted in inward
vertical and lateral migration from the surrounding area.
Because of the low concentrations of most target SVOCs in the pre- and post-treatment soil
samples, only benzo(a)anthracene was present in sufficient quantity to make a statistical evaluation. It
decreased 43 percent outside the revised treatment zone at the 90 percent confidence level; however, its
decrease inside the original zone was not statistically significant. It is not known why this compound
decreased outside the revised treatment zone.
High concentrations of several VOCs (toluene, chlorobenzene, methylene chloride) were detected
in some soil samples, but the changes in concentrations were not statistically significant. However most
target VOCs in the pre- and post-treatment soil samples had low concentrations, and a statistical
evaluation could not be made.
Several groundwater samples were collected to characterize the site and to determine whether
contaminants from the groundwater were migrating into the treatment zone. Chlorobenzene was one of
the predominant contaminants in the groundwater, but very little chlorobenzene was detected in the
revised and original treatment zones. The highest chlorobenzene concentrations were in the deeper soil,
closer to the groundwater.
Pretreatment chlorobenzene concentrations in the soil within the revised treatment zone ranged
from less than 22.7 ppb to less than 50 ppb, with none of the eight samples having concentrations above
the PQL level. Because of the low pretreatment concentrations within the revised treatment zone, no
statistically significant decrease could be observed. Chlorobenzene concentrations in the soil within the
remainder of the original treatment zone were higher, but no statistically significant decrease was
exhibited within the original treatment zone.
Chlorobenzene concentrations in the soil below the original treatment zone were significantly
higher than those inside the revised and original treatment zones. Analyses of soil samples below 20 feet
indicated chlorobenzene concentrations as high as 239,000 ppb in pretreatment and 291,000 ppb in post-
treatment samples. Even with these high starting concentrations, no statistically significant decrease of
55
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chlorobenzene was observed in the area outside the original treatment zone. However, this zone was not
heated or screened during the demonstration and was not expected to show contaminant decrease.
In spite of the fact that no statistically significant chlorobenzene decrease was observed in the
soil, SVE vapor stream data indicate significant amounts of chlorobenzene being extracted before, during,
and after the heating stage of the demonstration. It is possible that the amount of chlorobenzene extracted
from the soil was not enough to cause a statistically significant decrease. Alternatively, the chlorobenzene
present in the SVE vapor stream may indicate some source of chlorobenzene other than the soil.
Significant concentrations of chlorobenzene were found in groundwater samples collected from
surrounding wells before the demonstration. These wells are located outside of the treatment area
sampled for this demonstration. Chlorobenzene concentrations are 12,000 ppb in MW-09, 25,500 ppb
in MW-10, and 15,500 ppb in DW-02. This indicates that the groundwater, which is probably causing
high levels of chlorobenzene outside the demonstration area, may be a source of the chlorobenzene in the
SVE vapor stream.
4.5 RESIDUALS
The residuals resulting from the demonstration of the KAI RFH technology include soil;
contaminant vapors removed from the soil; condensate collected within the vapor treatment system;
washwater from equipment and personnel decontamination; and miscellaneous solid wastes, such as used
PPE. All residuals remained the responsibility of Kelly AFB. The treated soil was left in place, and soil
cuttings from drilling activities were drummed and removed from the site for disposal. Contaminant
vapors that condensed within the vapor treatment system were collected and transferred to a Kelly AFB
industrial wastewater treatment facility. Vapors that did not condense were channeled to a propane-fueled
flare for destruction.
4.6 REFERENCES
1. American Society for Testing and Materials, Annual Book of ASTM Standards.
2. U.S. Environmental Protection Agency, Test Methods for Evaluating Solid Waste (SW-846):
Third Edition, November, 1986, and Final Update, September, 1990.
3. U.S. Environmental Protection Agency, EPA Methods for Chemical Analysis of Water and
Wastes, 1983.
56
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SECTION 5
OTHER TECHNOLOGY REQUIREMENTS
5.1 ENVIRONMENTAL REGULATION REQUIREMENTS
State regulatory agencies may require permits for the onsite installation and operation of KAI's
RFH system. An air emissions permit may be required for the vapor treatment system. If offsite
disposal of contaminated residuals is required, the residuals must be removedfrom the site by a licensed
transporter. These residuals must be treated or disposed of by a permitted incinerator or other treatment
or disposal facility. Additional environmental regulations may apply, depending on the characteristics
of the specific site and the contaminants present.
5.2 PERSONNEL ISSUES
Proper PPE should be available and properly utilized by all onsite personnel. PPE requirements
will be site-specific and should be determined based on the contaminants present at the site and on the
work activities being conducted, During the demonstration, PPE levels were designated according to the
potential hazards associated with each work activity. At a minimum, Level D PPE was required for all
personnel working at Site S-l. During most demonstration activities, site personnel were not in contact
with the contaminated soil because it was covered with a layer of gravel. The potential for exposure to
soil contaminants was increased during drilling activities, including pretreatment sampling, installation
of subsurface system components, and post-treatment sampling.
Site monitoring should be conducted to identify the extent of hazards and to document exposures
at the site. Monitoring results should be maintained and posted. During the demonstration, a flame
ionization detector (FID) was used to monitor the air near the soil and in the breathing zone during
drilling, groundwater sampling, and related activities. Because the degree of soil and groundwater
contamination varied considerably, the drill crew and other personnel alternated use of Level C PPE and
Level D PPE. They upgraded to Level C PPE when the FID indicated breathing zone air contaminant
concentrations greater than 5 ppm over background for 5 minutes; they were permitted to downgrade to
Level D when the FID indicated breathing zone air contaminant concentrations less than 5 ppm over
background. Respirators were required periodically during both pre- and post-treatment sampling.
57
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OSHA 40-hour training covering PPE application, and health, and emergency
procedures should be tor all working with, the RFH technology. Additional training
provided prior to the operation of die at a given site should include Information, regarding
emergency evacuation safety locations; the of the exclusion zone,
zone, and zone; PPE and site- and technology-specific
hazards. Potential with the RFH drilling and personnel
exposure to RF fields. Safe operating procedures should always be observed, particularly during drilling
operations. Periodic monitoring for RF electromagnetic fields will also reduce the technology-specific
hazards.
Onslte In a program. Health and safety
monitoring and Incident reports should be routinely filed, and of occupational illnesses and
injuries (OSHA Forms 102 200) should be maintained. Audits, ensuring compliance with, the health
and safety should be carried out. In the event of an accident, illness, hazardous situation at the site,
or act of harm, should be sought from the local emergency response
and. aid or should be if To a
In of an emergency, review the plan, fircfigiiting procedures,
cardiopulmonary (CPR) techniques, and procedures before
the system. An evacuation vehicle should be available at all times.
5.3
Community of a technology is by both and perceived hazards. The
fact the RFH technology allows In situ of contaminated should improve the potential
for community acceptance, of volatile
Although some contaminants are likely to be released during electrode thermowell Installation, the
potential for during drilling is lower excavation.
Disadvantages with in situ 'RFH and, in situ are the difficulty of
determining the treatment has uniformly and the potential for contaminant
migration if pockets of contamination remain in the soil. Actual or perceived hazards associated with the
WF energy also become an Issue, as potential of electromagnetic fields have recently
received significant publicity. community education may be to residents'that the
operation of the RFH Is in compliance with, safety and guidelines. The American
58
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Conference of Governmental Industrial Hygienists (ACGIH) has established Threshold Limit Values
(TLVs) for radio frequency radiation. The TLVs are dependent on the frequencies of the radio waves.
TLVs and formulas for calculating TLVs are presented in Table 11. The RFH system used during the
SITE demonstration was designed to operate at a frequency of 27.12 MHz. TLVs for this specific
frequency are also presented in Table 11.
Table 11. Radio Frequency Radiation TLVs [1]
Frequency
27.12MHz
30 kHz to 3 MHz
3 MHz to 30 MHz
30 MHz to 100 MHz
100 MHz to 1,000 MHz
1 GHz to 300 GHz
Power Density
(mW/cm2)
1.22
100
900/f2
1
f/100
10
Electric Field
strength squared
(Wm2)
4,613
377,000
3,770(900/f2)
3,770
3,770 (f/100)
37,700
Magnetic Field
strength squared
(A^m2)
0.033
2.65
900/(37.7 x f2)
0.027
f/(37.7 x 100)
0.265
f = frequency in MHz
REFERENCE
American Conference of Governmental Industrial Hygienists. Threshold Limit Value. 1992.
59
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SECTION 6
TECHNOLOGY STATUS
KAFs RFH system was used to treat approximately 56 cubic yards of soil at Kelly AFB during
the SITE demonstration. The soil in the treatment zone was contaminated with mixed solvents, carbon
cleaning compounds, and petroleum oils and lubricants. The results of this demonstration are summarized
briefly in Section 4 of this report and are summarized in greater detail in Appendix A.
Prior to the SITE demonstration conducted at Kelly AEB, KAI's RFH system was tested at
several other sites. The results of two of these tests are available to the public. One test was conducted
at the Savannah River Superfund site to investigate the effectiveness of the KAI RFH system as an
enhancement to vacuum extraction. During the Savannah River test, KAFs RFH system was used in the
removal of residual solvents (primarily trichloroethylene and perchloroethylene) from vadose zone clay
deposits approximately 40 feet bgs. A second test was conducted to evaluate the ability of the KAI RFH
system to enhance the removal of #2 Fuel Oil from silty soil. Both tests are described in greater detail
in Appendix B.
60
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APPENDIX A
Performance Data
A.1 CHEMICAL ANALYSES
A.I.I Procedure for Selecting Contaminants for Statistical Evaluation
All soil samples were analyzed for TRPH, and half of the soil samples were analyzed forVOCs
and SVOCs. TRPH in the soil samples was extracted by Method 9071A prior to analysis by Method
418.1. VOCs in the soil samples were analyzed by Method 8240. Target VOCs are listed in Section 4,
Table 5. SVOCs in the soil samples were extracted by Method 3540 prior to analysis by Method 8270.
Target SVOCs are listed in Section 4, Tables 6 and 7.
The first step of the data evaluation process was to count the number of pretreatment samples in
which each target compound was detected above its method detection limit (MDL). Many target VOCs
and SVOCs were not detected in any pretreatment samples. Table A-l lists those compounds that were
detected and the number of samples in which each compound was detected above its MDL.
Only 13 contaminants were detected above their MDLs in over 15 samples (numbers shown in
bold in the second column of Table A-l). The number of complete matched data pairs inside the original
treatment zone was determined for each of these 13 contaminants. A complete matched pair consists of
a pretreatment sample and a post-treatment sample collected as close as possible to the pretreatment
sample. In order to be included in the evaluation process for a given compound, a matched pair must
also meet the following criteria:
1) The pre- and post-treatment concentrations of the selected compound must not both be below
their MDLs.
2) If either the pretreatment or post-treatment concentration of the selected compound is below
its MDL, its MDL must not be greater than the measured concentration of the other sample.
As shown in Table A-l, six of the contaminants evaluated had 10 or more complete matched
pairs within the original treatment zone (numbers shown in bold in the third column of Table A-l).
Practical quantitation limits (PQLs) of five times the MDLs were calculated for all data points for each
61
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Table A-l. Summary of Data Evaluation Process
Contaminant
# of pretreatment samples in
wnich contaminant was
detected above its MDL
# of complete matched pairs
within the orignal treatment
zone, based on MDLs
# of complete matched pairs
within the revised treatment
zone, based on PQLs
TRPH
Acetone
Benzene
Chloxvbenzene
Ethylbenzene
Methyl ethyl ketone
Methylene chloride
Tetrachloroethene
Toluene
Trichloroethene
Xylenes
Acenaphthene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Bis(2-cthylhexyl)phthalate
2-Chlorophenol
Chrysene
Dibenz(ah)anthracene
Dibenzofuran
1 ,2-Dichlorobenzene
1 ,3-Dichlorobenzene
1 ,4- Dichlorobenzene
2,4-Dimethylphenol
Di-n-butylphthalate
Fluoranthene
Fluorene
Hexachlorobenzene
Indeno (123cd)pyrene
2-mcthylnaphthalene
Naphthalene
Phenanthrene
1,2.4-Trichlorobenzene
Pvrene
TOTALS
64 40
14
2
29 9
5
221
20 0
1
20 3
1
11
7
9
16 13
15 13
17 14
27 16
1
16 12
4
5
14
14
15
5
10
27 19
13
2
11
20 9
15
23 13
6
22 18
519 188
20
2
0
1
5
4
5
5
5
0
5
57
a Similar concentrations were observed in laboratory blanks; therefore, this compound was not considered during tbe statistical analyses.
62
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of these six contaminants; these PQLs were then used during the statistical analyses. The use of PQLs
eliminates estimated values and results in more conservative evaluations. The number of complete
matched data pairs inside the original treatment zone was then redetermined for these six contaminants,
based on PQLs rather than MDLs.
Because the PQLs were five times the MDLs, the conversion to PQLs eliminated many complete
matched pairs. In addition, the SITE Program was informed at this point that KAI and B&RE changed
the test plan during installation and decided to heat only the upper half (approximately) of the original
treatment zone. Throughout this document, the upper half or the original treatment zone is referred to
as the "revised treatment zone", which ranges in depth from 4 feet to 14 feet. When the evaluation was
changed to the revised treatment zone, this further reduced the number of complete matched pairs. As
shown in the last column of Table A-l, TRPH had 20 complete matched pairs, within the heated zone
(using PQLs). All other contaminants evaluated had between zero and seven complete matched pairs
within the revised treatment zone.
As a result, paired t-tests for the revised treatment zone were performed on all VOCs which met
the first requirement. Paired t-tests were performed on all SVOCs which met the first two requirements
and also contained three or greater matched pairs in the revised zone. Results are reported only for those
compounds that exhibited statistically significant changes at confidence levels of 80 percent or greater.
The methodology for conducting a paired t test for a given compound is described in the following
subsection
A. 1.2 Methodology for Statistical Evaluation
The number of complete matched pairs for a given contaminant was determined and was
represented by N. Because the TRPH data were found to be log-normally distributed, logarithms of all
data were calculated before the data were manipulated. Xw was used to represent the pretreatment log
concentration of this compound from the i* sample location, and XS1 was used to represent the post-
treatment log concentration from the i* sample location (where i varied from 1 to N). The difference in
log concentrations (Xu - Xffl) was calculated for each data pair and was denoted by <^. The mean of the
differences in log concentrations was calculated according to the following formula:
63
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"ft
R was used to represent the geometric mean of the ratios of post-treatment concentration to
pretreatment concentration, which was calculated from the geometric mean of the differences in log
concentrations according to the following formula:
R = 103
R was then converted to either percent decrease or percent increase, as appropriate.
The standard deviation of the differences in log concentrations was calculated according to the
following formula:
\
N-1
M
£ C4
i=i
It was assumed that the unknown pre- and post-treatment logmean concentrations throughout the
entire site were % and % respectively, and the logvariances were equal. The following equation defines
the statistic used in the paired t-test:
The resulting value of t was compared to tabulated values of t for two-tailed tests to determine the
probability that the measured change (percent decrease or percent increase) was representative of the
revised treatment zone.
A. 1.3 Data Summary
TRPH
Tables A-2 through A-7 present pre- and post-treatment TRPH data from analyses of soil
samples. The sample locations presented in these tables correspond to the subsurface components labeled
on Figure 1 .
64
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Table A-2. TRPH Samples Revised Zone (ppm)
Sample Location
E1-U1012
E6-U0810
F1-U0406
F1-U1012
E4-U0709
E4-U0911
F4-U1214
E2-U1012
F3-U0406
F3-U1012
E7-U1214
E5-U0406
E5-U0608
E5-U1012
E5-U1214
F5-U1214
A2-U0406
A2-U1012
A2-U1214
E8-U0608
Pretreatment
Reported Value
(* if PQL)
3,350
1,860
6,910
1,240
1,310
729
1,790
168.5*
4,920
336
1,400
2,710
1,530
668
739
1,220
1,530
1,290
622
655
Post-treatment
Reported Value
(* if PQL)
1,160
930
828
1,580
1,090
593
643
582
702
4,510
825
673
587
330
1,450
1,530
154
33.3 *
106
861
Post-treatment •
Pretreatment Value
-2,190
-930
6,082
340
-220
-136
-1,147
414
-4,218
4,174
-575
-2,037
-943
-338
711
310
-1,376
-1,257
-516
206
65
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A-3. TMPH
Sample Location
E1-U0002
E1-U1012
E1-U1618
A1-U0002
A1-U1618
A1-U1820
E6-U0810
E6-U1618
F1-U0406
F1-U1012
F1-U1820
E4-UG7G9
E4-U0911
F4-U0002
F4-U1214
F4-U1618
E2-UQOG2
E2-U1012
F3-U0406
F3-U1012
E7-U0204
E7-U1214
F2-U1416 '
E5-U0406
E5-U0608
E5-U1012
E5-U1214
E5-U1820
F5-U1214
Pretreatment
Reported Value
(*if'PQL)
352
3,350
22,000
458
79,700
39,300
1,860
3,160
6,910
1,240
5,440
1,310
729
1,220
1,790
1,090
1,730
168.5*
4,920
336
492
1,400
3,250
2,710
1,530
668
739
105,000
1,220
Post-treatment
Reported, Value
(* if PQL)
4,830
1,160
19,200
184
20,800
28,300
930
253
828
1,580
23,100
1,090
593
448
643
12,500
3,620
582
702
4,510
161
825
555
673
587
330
1,450
35,800
1,530
Post-treatment -
Pretrcatinent Value
•4,478
2,190
2,800
274
58,900
11,000
930
2,907
6,082
-340
-17,660
220
136
772
1,147
-11,410
-1,890
-414
4,213
-4,174
331
575
2,695
2,037
943
338
-711
69,200
-310
66
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Table A-3. (continued)
Sample Location
Pretreatment
Reported Value
(* if PQL)
Post-treatment
Reported Value
(* if PQL)
Post-treatment -
Pretreatment Value
F5-U1618
F5-U1820
E3-U1416
E3-U1618
A2-U0002
A2-U0204
A2-U0406
A2-U1012
A2-U1214
A2-U1618
E8-U0608
22,100
35,000
1,210
7,410
2,330
203
1,530
1,290
622
23,800
655
20,900
53,200
1,770
2,820
8,850
2,570
154
11
33.
106
6,500
861
1,200
-18,200
-560
4,590
-6,520
-2,367
1,376
1,257
516
17,300
-206
67
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A-4.
Sample Location
E1-U0002
E1-U1618
E1-U2425
A1-U0002
A1-U1618
A1-U1820
A1-U2728
E6-U1618
E6-U2022
F1-U1820
E4-U2426
F4-U0002
F4-U1618
F4-U28291
E2-U0002
E2-U2628
F2-U1416
F2-U2628
E5-U1820
E5-U2022
F5-U1618
F5-U1820
F5-U2324
E3-U1416
E3-U1618
E3-U2022
E3-U2829
A2-U0002
A2-U1618
Pretreatment
Reported Value
(*ifPQL)
352
22,000
4,690
458
79,700
39,300
2,240
3,160
22,700
5,440
3,660
1,220
1,090
1,670*
1,730
4,440
3,250
4,440
105,000
43,500
22, 100
35,000
10,300
1,210
7,410
1,360
325
2,330
23,800
Post-treatment Post-treatment-
Reported, Value Pretreatment Value
(* ifPQL)
4,830
19,200
6,830
184
20,800
28,300
5,880
253
92,600
23,100
3,170
448
12,500
1,520
3,620
23,100
555
6,270
35, mo
31,200
20,900
53,200
7,590
1,770
2,820
58,800
3,810
8,850
6,500
4,478
-2,800
2,140
-274
-58,900
-11,000
3,640
-2,907
69,900
17,660
-490
-772
11,410
-150
1,890
18,660
-2,695
1,830
-69,200
42,300
-1,200
18,200
-2,710
560
-4,590
57,440
3,485
6,520
-17,300
68
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Table A-4. (continued)
Sample Location
A2-U2022
A2-U2628
E8-U2426
E8-U2628
TD3-U0406
TD3-U1416
TD3-U2426
TD5-U0406
TD5-U1416
TD5-U2425
TD6-U0406
TD6-U1416
TD6-U2527
Pretreatment
Reported Value
(* if PQL)
21,200
2,730
10,100
2,060
1,420
171.5*
5,700
445
31,300
2,080
538
2,980
2,940
Post-treatment
Reported Value
(* if PQL)
58,900
4,800
6,060
3,060
4,740
1,940
5,040
762
1,540
14,300
893
6,120
2,020
Post-treatment-
Pretreatment Value
37,700
2,070
4,040
1,000
3,320
1,769
660
317
-29,760
12,220
355
3,140
-920
1 Because the pretreatment PQL for this sample pair is greater than the post-treatment concentration, this sample pair was not included in
the statistical evaluation of the data.
69
-------
Table A-5. TRPH Samples Outside Original Treatment Zone (ppm)
Sample Location
E1-U2425
A1-U2728
E6-U2022
E4-U2426
F4-U28291
E2-U2628
F2-U2628
E5-U2022
F5-U2324
E3-U2022
E3-U2829
A2-U2022
A2-U2628
ES-U2426
ES-U2628
TD3-U0406
TD3-U1416
TD3-U2426
TD5-U0406
TD5-U1416
TD5-U2425
TD6-U0406
TD6-U1416
TD6-U2527
Pretreatment
Reported Value
(* if PQL)
4,690
2,240
22,700
3,660
1,670*
4,440
4,440
43,500
10,300
1,360
325
21,200
2,730
10,100
2,060
1,420
171.5*
5,700
445
31,300
2,080
538
2,980
2,940
Post-treatment
Reported Value
(* if PQL)
6,830
5,880
92,600
3,170
1,520
23,100
6,270
31,200
7,590
58,800
3,810
58,900
4,800
6,060
3,060
4,740
1,940
5,040
762
1,540
14,300
893
6,120
2,020
Post-treatment-
Pretreatment Value
2,140
3,640
69,900
-490
-150
18,660
1,830
-12,300
-2,710
57,440
3,485
37,700
2,070
-4,040
1,000
3,320
1,769
-660
317
-29,760
12,220
355
3,140
-920
I Because the pretreatment PQL for this sample pair is greater than the post treatment concentration, this sample pair was not included in
the statistical evaluation of the data.
70
-------
Table A-6. TRPH Samples Al Zone (ppm)
Sample
Location
E1-U1012
E6-U0810
F1-U0406
F1-U1012
E4-U0709
E4-U0911
F4-U1214
E2-U1012
F3-U0406
F3-U1012
E7-U1214
E5-U0406
E5-U0608
E5-U1012
E5-U1214
Pretreatment
Reported Value
(* if PQL)
3,350
1,860
6,910
1,240
1,310
729
1,790
168.5*
4,920
336
1,400
2,710
1,530
668
739
Post-treatment
Reported Value
(*ifPQL)
1,160
930
828
1,580
1,090
593
643
582
702
4,510
825
673
587
330
1,450
Post-treatment •
Pretreatment Value
-2,190
-930
-6,082
340
-220
-136
-1,147
414
4,218
4,174
-575
-2,037
-943
-338
711
71
-------
Table A-7. TRPH Samples A2 Zone (ppm)
Sample
Location
E2-U1012
E4-U0709
E4-U0911
F3-U0406
F3-U1012
E7-U1214
E5-U0406
E5-U0608
E5-U1012
E5-U1214
F5-U1214
A2-U0406
A2-U1012
A2-U1214
E8-U0608
Pretreatment
Reported Value
(*ifPQL)
168.5*
1,310
729
4,920
336
1,400
2,710
1,530
668
739
1,220
1,530
1,290
622
655
Post-treatment
Reported Value
(* if PQL)
582
1,090
593
702
4,510
825
673
587
330
1,450
1,530
154
33.3*
106
861
Post-treatment -
Pretreatment Value
414
-220
-136
-4,218
4,174
-575
-2,037
-943
-338
711
310
-1,376
-1,257
-516
206
72
-------
Table A-8 summarizes the TRPH pretreatment and post-treatment concentration geometric means
and percent decreases. Figure A-l summarizes the TRPH contaminant concentrations used in the final
statistical evaluation. To illustrate sampling locations, the results are presented on cross-sections of the
original design treatment zone. This figure consists of three cross-sections of the original design
treatment zone. The first cross-section shows samples collected from the ground electrode row E-l to
E-3, the second cross-section shows samples collected from the exciter electrode row, and the third cross-
section shows samples collected from ground electrode row E6 through E8. TD3 is actually outside the
original treatment zone entirely, but is included in the first cross-section for convenience. TD5 and TD6
are included in the second cross-section because they are in line with the exciter electrodes.
Both the original and revised design treatment zones are shown on the cross-sections. For each
cross-section, samples included in the original treatment zone are inside a box formed by a thin black
line. Samples included in the revised treatment zone are inside a box formed by a thick black line.
In Figure A-l, the TRPH concentration is presented on a dry-weight basis. When TRPH was not
detected at or above its PQL, the PQL is presented. An asterisk to the right of a value indicates that
value is the PQL, rather than a measured concentration.
SVOCs and VOCs
Tables A-9 and A-10 summarize the pre- and post-treatment geometric mean concentrations and
percent decreases in each of the zones for the primary SVOC and VOC contaminants respectively.
Figures A-2 through A-9 summarize the SVOC and VOC contaminant concentrations used in the final
statistical evaluation. These figures are in the same format as the data presented for TRPH in Figure A-l.
SVE Vapor Stream
The vapor stream was sampled and analyzed at six critical points during the demonstration.
Sampling times are summarized in Table A-ll, and vapor extraction system conditions during sampling
are summarized in Table A-12. Concentrations of VOCs and SVOCs in the vapor stream from the six
sampling points are summarized in Tables A-13 and A-14, respectively.
73
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Table A-8. Summary of TRPH Percent Change
Treatment Zone
Revised
original
Outside Revised
Outside Original
Al
A2
Pretreatment
Geometric Mean (ppm)
1,238
2,141
4,259
3,289
1,382
981
Post-treatment
Geometric Mean (ppm)
636.9
1,497
5,862
6,444
1,008
520
Percent Change
49% decrease11
29% decrease"
39 % increase6
96% increase11
a
44% decrease0
a Not accepted at an 80 percent significance level.
b Accepted at a 95 percent significance level.
c Accepted at an 80 percent significance level.
d Accepted at a 97.5 percent significance level.
e Accepted at a 90 percent significance level.
77
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101
-------
A-9. of SVOC
Contaminant
Benzo(b)fluoranthene
Benzo(a)anthracene
Benzo(a)pyrane
Bis(2-«thylhexyl)phthalate
Chrysene
Pyrene
Fluoranthene
Pretreatment Geometric
Mean
Treatment Zone (ppm)
Revised
Original
Outside Revised
Outside Original
Revised
Original
Outside Revised
Outside Original
Revised
Original
Outside Eevise4
Outside Original
Revised.
Original
Outside Revised
Outside Original
Revised
Original
Outside Revised
Outside Original
Revised
Original
Outside Re¥ised
Outside Original
Revised
Original
Outside Revised
Outside Original
.5271
.7653
,5907
.1908
,2249
,2969
,2784
.115?
.2112
.3533
,5917
_>
1.921
5.752
9.372
5,362
.3129
.3768
.4071
_>
.5503
.5865
.3597
.1229
.5084
,8462
1,368
1.309
Post-treatment
Geometric Mean
(ppm)
.3168
,4315
,4669
,3046
.1401
.2181
.1583
.1024
.1204
,1966
.3330
__b
.5141
2.593
7.861
8.239
,1.879
.2863
.2971
_>
.2203
.3269
.2373
.1491
.2399
.6063
.9958
1.188
Percent
Decrease
40C
44d
at
™m
JM
™~_lift
43f
a
43°
44°
.™,™~m
b
,~_a
55f
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at
40=
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a.
_>
601"
—^
„„„„_„„$
a
53C
™™* *
a
s
a .Not accepted at ait 80 percent eoafidcnc* level.
b Value could not be deterroiiiedL
s Accepted ai a SO percefii confidence level.
d Accepted at. a 97,.5 percent confidence level
e Accepted at a 95 perceal confidence level,
f Accepted at a 90 percent confidence level.
102
-------
A-10. of VOC
Contaminant
Toluene
Chlorobenzene
Methylene Chloride
Treatment
Zone
Revised
Original
Outside
Revised
Outside
Original
Revised
Original
Outside
Revised
Outside
Original
Revised
Original
Outside
Revised
Outside
Original
Pretreatment Post-treatment
Geometric Meaa, Geometric Mean
(ppb) (,ppb)
.__» __*
134.2 437.7
15,851 9,078
12,71.5 7,54?
23.59 38.41
2,058 1,201
20,360
37,326 53,265
__» __*
— * — *
_» __«
_* __*
Percent
Decrease
_•
— b
b
— -b
_>
— b
_J»
_J»
__»
__»
-™™™™.1
—^
a Due to the hck of matched pairs, the value could not be determined
b Not accepted at an 80 percent confidence level.
103
-------
A-ll. Times for SVE
Sample Date System Condition
April 8, 1994 Vapor extraction system, on, RFH yet to begin,
May 6, 1,994 RFH system on (since April 24, 1994}
May 31, 1994 Soil temperature at approximately 100°C in areas near operating
antennae
June 7, 1994 Maximum soil temperature achieved just prior to RFH system being
turned off
June 14, 1,994 Soil cooling, vapor extraction system on
June 24, 1994 Just prior to vapor extract) m \ ftnj mm »«tt
Table A-12. S'VE During
Date
04/08/94
04/08/94
05/06/94
05/31/94
06/07/94
06/14/94
06/24/94
•PCH.O)
1,35
0,30
0,1,0
0,45
0,40
0,64
0.25
Pressure
("Kg)
28.25
26.69
26,69
2,7,34
28.25
28,47
28,69
Temperature
fF)
90
105
126
15?
157
100
116
Moisture*
2,0
10,0
1 0.0
32.0
32,0
8.2
5,0
Duct Velocity
(ft/sec)
81,91
40.89
24,04
54,08
50.16
57,37
36.00
AC.FM2
108,1
54.0
31.7
71,4
68,2
75.7
10
DSCFM3
96,4
40,6
23,0
38.1
36,5
62.6
' .
ust gas moisture content eMHiwtoBoaieaoSauH^niperacyre anaiTioSSreiractioooasea^ssaGjraiioa uif f
"* Actual cubic feet per minute,-,
3 Dry standard cubic feet per minute.
104
-------
in the
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Fluorene
2-Melhylnaphthalene
N-Nitroso-di-n-propylamine
'
Phenanthrene
1 ,2,4-TrichIorobenzene
* 4 *..-#
ND
10.2
ND
14.7
ND
4,!
5J.7
10.2
147
ND
22!
24. 0
124
ND ND
59,1 j 83.2
83,7 | ND
166 1 177
ND I ND
ND 1 ND
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BroiiHiiwrni
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401
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259
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38,6
260
107
423
108
-------
109
-------
Soil Vapor Analysis
Soil vapor was sampled and analyzed at six locations after the demonstration. Table A-15
summarizes the VOC concentrations in each of the soil vapor samples.
Groundwater
Table A-16 summarizes the pretreatment groundwater analytical results of samples taken from
wells MW-10, MW-09, and DW-02. The groundwater was analyzed for TRPH, SVOCs, and VOCs.
A.2 Particle Size Distribution Analyses
Tables A-17 and A-18 present the results of particle size distribution analyses, which were
conducted to characterize the soil. Particle size analyses were conducted using two techniques: dry-
sieving and wet-sieving. The majority of the samples were just dry-sieved; however, a few samples were
wet-sieved. Particle size distribution data from dry-sieving is presented in Table A-17 and particle size
distribution data from wet-sieving is presented in Table A-18. For evaluation purposes, the data were
simplified into three categories: gravel, sand, and fines. Particles that are less than 3 inches (7.62 cm)
in diameter but will not pass through a #4 sieve (4.750 mm) are classified as gravel, particles that will
pass through a #4 sieve but will not pass through a #200 sieve (0.075 mm) are classified as sand, and
particles that will pass through a #200 sieve are classified as fines.
Contrary to what was expected, wet-sieving produced significantly different results than did dry-
sieving. Discussions with laboratory personnel indicated that the two procedures should have yielded
similar results. Since dry-sieving is less costly, and the use of dry-sieving was part of the approved
Demonstration Plan, the decision to dry-sieve seemed to be sound. It appears, however, the sample
preparation associated with the dry-sieved samples was not rigorous enough to break down many of the
cohesive silt and clay particles into sixes that would pass the #200 sieve. The results from the dry-sieving
probably do not reflect actual site conditions, and the percent sand data are likely to be lower and the
percent fines correspondingly higher. As a result, only particle size distribution data from wet-sieving
are being used to characterize the site. The data from dry-sieving are not being used.
110
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ylpentane
loDCinethane
ncthylpeniune
__,
-
186,000
124,000
2,0213
1,540
157,000
ND
21,900
77,100
176,000
40,400
90,400
563,000
78,400
87,400
ND
4 1 ,900
48,100
89,5
87,700
3,480
1,090
ND
2,990
25.6
2,780
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589
3,320
4,150
1,320
613
13,400
669
5,820
354
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38,6
3,120
209
5,520
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10,000
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9,050
ND
19,500
15,500
20,400
11,100
63,2
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40,100
3,300
11,600
13,700
*
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2,590
2,230
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3,490
8.0
3,660
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4,280
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1,490
740
93,700
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6,710
354
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2,060
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ND
14,100
18,700
21,600
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9,6
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2,570
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112
-------
HV.
"f"«,3.«;- -..
; I ! I : P 3^5 ' i'
Dibruinochloroiuelhane
3-Methylheptane
Hexanal
1,2-Dibromoetliane
2,2,5-Triinethylhexane
I -Octcne
n -Octane
Tetrachtoroelhylenc
Cliiorobciizene
Hlhylbenzene
p-Xylene + in-Xylene
Bruinuturni
Styrene
Hepianal
1 , 1 ,2,2-Tetrachluroethane
<>-Xylene
n-Ni)iiane
lsoprojwlbenz«JiWJ
a-Pinene -f
n - P top
m-Hlhyiloluene
p-Gthyltoluene
ND
14,It30
20,200
8,5
35,800
ND
23.SOO
2,470
22,000
ND
ND
ND
ND
6,070
17,100
ND
4,560
ND
ND
4,070
19.7
424
1,770
48,0
1,280
ND
700
187
11,700
595
1S240
63,0
278
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119
219
101
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5,880
20,900
ND
18,400
1,080
6,000
6,5
168,000
3,110
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2,920
ND
ND
792
617
l,9!0
7,130
3,520
494
4,560
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7,950
612
2,730
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713
181
358
214
604
462
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11,000
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9,190
523
2,680
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123
271
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363
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113
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Table A-16. Summary of Groundwater Sampling Results
Well ID Number
MW-10
MW-09
Measurement
TRPH (mgL)
Volatiles (ug/L)
Acetone
Benzene
Chlorobenzene
Trans- 1,2-Dichloroethene
Methyl ethyl ketone
4-Methyl-2-Pentanone (MIBK)
Toluene
Vinyl Chloride
Semivolatiles (jjLgfL)
2,4-Chlorophenol
2-Chlorophenol
1, 2-Dichlorobenzene
1,3-Dichlorobenzene
1, 4_Dichlorobenzene
2-Methylnaphthalene
Naphthalene
Phenol
1,2, 4-Trichlorobenzene
TRPH (mg/L)
Volatiles (ug/L)
Benzene
Chlorobenzene
Ethylbenzene
Toluene
Vinyl Chloride
Xylenes
Semivolatiles (/ig/L)
2-Chlorophenol
1, 2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
2-Methylnaphthalene
Naphthalene
Phenol
Result
4.92
61.9
782
25,500
14.0
16.4
11.5
51.2
28.0
36.3
193
11,200
760
2160
16.2
121
22.3
51.4
0.834
596
12,000
91.9
5.65
10.2
12.0
37.4
163
23.5
183
59.2
71.1
3.58
115
-------
Table A-16. (continued)
Well ID Number
Measurement
Result
DW-02
TRPH (mg/L)
Volatile s(ug/L)
Chlorobenzene
Semivolatiles (ug/L)
Acenaphthene
2-Chlorophenol
1 ,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
bis(2-ethylhexyl)phthalate
Fluoranthene
Fluorene
2-Methylnaphthalene
Naphthalene
Phenanthrene
1,2,4-Trichlorobenzene
267
15,500
7.79
22.1
1820
152
529
218
29.3
7.51
124
86.8
7.17
15.5
116
-------
A-17. Size (Dry-Sieving)
»,4 i/'t 'Li
\\ "'"-'.I
M ;\ih
A2-U0002**
A2-U0204
A2-U1214
A2-U1618
A2-U2022
A2 "132623
E1-U0002**
E1-U1012
El -U 1618
E2-U2628
E3-U1416
E3-U1618
E3-U2022
E4 - U0709
E4-U0911
E4-U2426
E5-U0406
E5-U0608
85 -U 1012
E5-U1214
E5-U1820
E5-U2022
E6-U0810**
E6-U2022
E7 U0204
E7-U1214D
E8-U0608
E8-U2426
E8-U2628
F1-U1012
F! -U1820
F2-U1416
F2-U2628
F3-U0406
F3 -01012
F4-U0002
F4-U1214
F4-U2829
F 5 -111214
F5-U1618
F5-U1820
TD3-U1416"
TD3-U2426
TD5-U0406
TD5-U1416
TD5-U2425
TD6-U0406
TD6-U2426
Average
i'tl ! It "
'' ( 11 tVft
i i"
K ,ti»
27.4%
23,7%
23.4%
18.3%
5,6%
79,1%
32,6%
36.9%
61,0%
67.3%
15.0%
8.2%
6,6'*
11.2%
27.11%
61.5%
23.5%
20.9%
32.2%
13.0%
13,7%
29.7%
33.3%
48.2%
50.9%
25,1%
33.4%
66.7%
51.2%
14.8%
53,7%
7.7%
59,1%
40.1%
20,8%
36.2%
21.4%
73.1%
19,1%
25.5%
27.2%
45,5%
67,7%
31.2%
25.2%
55,9%
36,2%
62.3%
35,4%
Hi
Ml i
!' i
>»' i
68,4%
74.3%
72,6%
793%
37,5%
20,3%
64.0%
57.9%
36.4%
32,2%
81.6%
84.1%
85.9%
84.3%
61.6%
34,4%
72,1%
72.8%
61.9%
77.8%
80.3%
64,4%
61.9%
48.6%
46,0%
63.3%
63,1%
30.8%
45.4%
79,8%
40.1%
84.2%
38.5%
55.6%
72,0%
592%
67.9%
25,4%
73.2%
67,4%
67,1%
49.4%
30.1%
62,1%
69.1%
43.4%
58.3%
36,8%
59.8%
Post —treatment
! fi «,
6 *
* 1 !
4,3%
2.0%
4.0%
2,4%
6.9%
0.6%
3,5%
5.2%
2.6%
0,5%
3,4%
7.7%'
7.5%
4,5%
11.4%
4.1%
4.4%
6.3%
5.9%
9.2%
6,0%
5.9%
4,9%
3.2%
3.1%
11.1%
3.5%
2,5%
3,4%
5.4%
6,2%
8.1%
2.4%
4.3%
7.2%
4/i%
10,7%
1.5%
7.7%
7.1%
5.7%
5.2%
2.2%
6,7%
5,7%
0.7%
5.5%
0.9%
4.8%
Sample ID
Al A -110002**
A1A-U1820
A1A-U2627
A2A-U0002
A2A-U0204
A2A-U0406
A2A-U1012**
A2A-U1214**
A2A-U2022
E1A-U0204
E1A-U1618
E1A-U2425
E2A-U0204
E2A-U1012
E3A-U1416
E3A-U1618
E3A-U2022"
E3A-U2830
E5A-U0406
E5A-U0608
E5A-U1214
E5A-U1820**
E5A-U2022
E6A-U0810
E6A-U1618
E7A-U0204
E7A-U1214**
E8A-U2426
E8A-U2628
F1A-U1820
F2A-U2628
F3A-U0406
F4A-U0002
F4A-U1214
F4A-U1618
F4A-U2830
F5A-U1214
F5A-U1618
F5A-U1820
F5A-U2224
TD3A-U0608
TD3A-U1416
TD3A-U2426
TD5A-U1416
TD6A-U0406
TD6A-U1416
Average
% Grave!
35.4'*
41.5%
63,8%
35.8%
33.4%
34.0%
33.4%
20.2%
29.6%
43,9%
51.4%
60,5%
51.7%
48.5%
42.7%
29.7%
17.9%
59.5%
57.5%
27.8%
63,9%
28.9%
29,6%
35.2%
41.3%
58,1%
33.0%
77.8%
60,7%
37,0%
65,9%
48,4%
45.2%
34,2%
15,9%
69.8%
38.3%
44.8%
40.7%
56,9%
52,7%
25,8%
73,7%
61.5%
43.6%
50.6%
44.6%
% Sand
59,3%
50,2%
34.6%
58.7%
63.3%
58.1%
54.7%
69.8%
66.6%
54,9%
43.8%
38,1%
44,3%
48,6%
51.0%
61.2%
73.0%
38,5%
37,3%
61.6%
33.5%
63.4%
64,0%
62.2%
54.5%
39,4%
61,5%
20.4%
37,4%
56,5*
33.5%
45,0%
51.9%
63,5%
77,8%
29.1%
58.4%
51.5%
53.1%
40,6%
45.0%
71,0%
25,1%
33.8%
53.7%
44.4%
50,8%
% Fines
5.4%
8,3%
1.6%
5.5%
3.3%
7.9%
12.0%
10.1%
3.8%
1.2%
4.8%
1.4%
3,5%
2.9%
6.3%
9.1%
9.2%
2,0%
5.2%
10.6%
2,6%,
7,7%
6,4%
2,6%
4.2%
2.5%
5.6%
1.8%
1.9%
6,5%
0.6%
6,6%
2.9%
2.3%
6,3%
1.1%
2,8%
3.7%
6.2%
2.5%
2.3%
3,2%
1.2%
4,7%
2,7%
5,0%
4,6%
•'Particle size distributions determined by dry-sieving were significantly different than those determined by wet —sieving,
** Average of two duplicate analyses.
117
-------
Table A-18. Particle Size Distribution Data (Wet-Sieving)
Pretreatment Post -treatment
Sample ID % Gravel % Sand % Fines Sample ID % Gravel % Sand % Fines
A2-U0002 34.4% 29.5% 36.1% A2A-U1618 42.5% 27.0% 30.5%
A2-U0406 19.2% 48.0% 32.8% E1A-U0204 43.7% 33.2% 23.1%
A2-U1012** 22.9% 34.3% 42.8% E5A-U1012 29.6% 23.9% 46.5%
E2-U1012 19.8% 30.3% 49.9% E8A-U0608 43.6% 26.9% 29.5%
E3-U2830 44.8% 38.3% 16.9% TDSA-U0406 47.5% 30.5% 22.0%
E6-U1618 32.7% 19.5% 47.8% TD6A - U2627 50.2% 32.9% 16.9%
E7-U1214** 5.2% 21.3% 73.6% Average 42.9% 29.1% 28.1%
F5 -U2324 56.5% 24.5% 19.0%
Average 29.4% 30.7% 39.9%
• Pardcle size distributions determined by dry-sieving were significantly different than those determined by wet -sieving.
. ** Average of two duplicate analyses.
A.3 Moisture Data
Moisture analyses were conducted so that soil sample concentration results could be converted to
dry weight results. Figure A-10 presents the results of moisture analyses in the same format used to
present the results of the chemical analyses. Based on the final statistical evaluation, there were
statistically significant decreases in percent moisture inside the original and revised treatment zones.
Moisture results for all zones are summarized in Table A-19.
Table A-19. Summary of Percent Moisture Results
Estimated Change in Confidence Level
Mean Concentration
Inside Original Treatment Zone -53 % > 99.9%
Inside Revised Treatment Zone -70% >99%
Outside Original Treatment Zone + 19% >95%
•k .k .k .k
Outside Revised Treatment Zone
= Did not exhibit a statistically significant change at 80% confidence level.
118
-------
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-------
A.4 Operational and Process Data
Operational data for the KAI RFH SITE Demonstration was collected primarily by KAI and by
the USAF contractor, B&RE. Operational data collected by B&RE and KAI were not independently
verified by the SITE Program or its contractors. Table A-20 summarizes extraction well pressures and
temperatures during the demonstration. Table A-21 summarizes the compressor and flare flow rates
during the demonstration.
Table A-20. Summary of Operating Conditions Data
Well
El
E2
E3
E4
E5
E6
E7
E8
MinimumPressure
(in. H20)
-17.0
-30.0
-30.0
-49.0
-72.1
-3.3
-3.8
-4.6
Maximum
Pressure
(in. 11,0)
0
0
0.1
-0.4
0
-0.3
0
0
Minimum
Temperature
(°C)
18.9
19.8
19.4
18.1
23.3
19.5
19.5
19.7
Maximum
Temperature
CO
36.6
60.7
45.3
93.5
93.5
31.7
31.3
31.4
Table A-21. Summary of Compressor and Flare Flow Rates
Component
Compressor
Flare
Minimum Flow Rate (scfm)
35
50
Maximum Flow Rate (scfm)
70
140
A.4.1 Temperature
Soil temperatures within and outside the revised treatment zone were indirectly monitored at
various depths throughout the demonstration. The demonstration system was designed to heat the soil
in the revised treatment zone to a temperature range of 100 to 130°C. Soil temperatures within and
outside the revised treatment zone were monitored at various depths throughout the demonstration using
122
-------
thermocouples, infrared temperature sensors, and fiberoptic temperature probes. All temperature
measuring devices were mounted in lined boreholes, which made direct readings of the soil temperature
impossible. The developer claims that actual soil temperatures were higher than the measurements
indicate; however, this difference cannot be quantified. The maximum measured temperature on the
perimeter of the revised treatment zone was 61°C The maximum measured temperature near the center
of the revised treatment zone was 234°C, but this peak was not representative of the majority of the
temperature measurements at this location. During most of the heating period, temperatures between 100
and 150°C were measured near the antenna to which energy was being applied. Although not observed
during the demonstration, the developer claims that temperatures will become more uniform after all
moisture is removed from around the antennae.
A.4.2 Residuals
Condensate from the vapor treatment system was pumped into a 500-gallon truck-mounted tank
during the KAI RFH SITE demonstration. The condensate was transferred to the Kelly AFB
Environmental Pollution Control Facility for treatment and discharge. Approximately 2,000 gallons of
condensate were collected from the vapor treatment system during the KAI demonstration.
All soil cuttings were drummed and transferred to the Kelly AFB Drum Lot for disposal. Soil
cuttings filled 40 drums during pretreatment sampling and 35 drums during post-treatment sampling. One
drum filled with miscellaneous solid wastes (PPE, plastic sheets, etc.) was also transferred to the Kelly
AFB Drum Lot for disposal.
A.4.3 Utilities
According to measurements taken by KAI, 15,749 kW of RF energy were delivered to the soil
during the demonstration. Based on a 90 percent delivery efficiency, KAI estimates that 17,351 kW of
RF energy were generated by the RF source. KAI further estimates, based on a 65 percent conversion
efficiency, that 26,693 kW of AC electric power were consumed by the RF source. Total electric
consumption for the site was measured during the demonstration. The B&RE project report states that
36,053 kWh of electricity were consumed during the project.
123
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A.4.4 RF Emissions and Electric Field Measurements
RF emissions were measured with a broad band, vertically polarized, 2-meter high, calibrated,
biconical antenna. The antenna signal was processed by a portable calibrated spectrum analyzer. Initial
and closing measurements were witnessed by representatives of the Kelly AFB frequency management
office. Detailed tests were logged on May 3, 18, and 24, 1994 and on June 6, 7, 8, and 10, 1994.
The first through sixth harmonics of the operating frequency were measured in compliance with
FCC part 18.305(b). Part 18.305(b) specifies a harmonic emission limit of 169 uV/m or 44.58 dB-uV/m
at a distance of 300 m for the operating frequency of 27.12 MHz. Harmonics were measurable 10 meters
from the active antenna but were typically unmeasurable or at the threshold of detection 300 meters from
the active antenna. On June 7, with the RF generator operating at 23.21 kW, the second harmonic was
detected at 2 uV/m or 3.90 dB-uV/m, which is easily within the FCC emission limit.
In addition to the harmonics, fundamental frequency emission levels (27.12 MHz) were measured
in compliance with USAF requests. Surface emissions 10 m from the active antenna were typically about
0.4 V/m when the RF generator was operating at 20 kW The highest surface emission measured 10 m
from the active antenna was 1 V/m during an RF generator output power level of 23.56 kW. The highest
surface emission measured 300 m from the active antenna was 0.25 V/m during an RF generator output
power level of 23 kW.
The electric field at the site was measured with the calibrated electric and magnetic probes of a
broad-band isotropic field strength meter. Electric field measurements were taken at defined locations
on 23 heating days. Initial measurements were witnessed by Kelly AFB site safety personnel.
The site safety plan required maintaining the 6-minute average electric field exposure level for
site personnel below 70 V/m. The permissible exposure limit (PEL) of 70 V/m was calculated for the
27.12 MHz operating frequency using a formula from AFOSH Standard 161-9, February 12, 1987.
Electric field measurements are summarized in Table A-22.
The only electric field measurements that exceed 70 V/m were taken O.lm from the antenna.
The electric field strength that close to the antenna is not believed to represent a risk to incidental human
exposure. In addition, two red warning lamps, which were controlled directly by the RF generator's
power enabling circuitry, alerted site personnel when the RF generator was operating.
124
-------
Table A-22. Summary of Electric Field Measurements
Distance from Active Antenna
Range of Electric Field Measurements
O.lm
1m
3m
10m
25 to 132
7 to 59.1 V/m
1 to 14 V/m
up to 1 V/m
125
-------
APPENDIX B
CASE STUDIES
B.I SAVANNAH RIVER SUPER FUND SITE
The objective of the demonstration was to investigate the effectiveness of the KAI RFH system
as an enhancement to vacuum extraction of residual solvents (primarily trichloroethylene and
perchloroethylene) held in vadose zone clay deposits approximately 40 feet below the surface at the
Savannah River Super-fund site. The KAI RFH system is mounted in an 8 ft x 8ft x 20 ft shelter that
is mobilized by a 28-foot flatbed trailer and a 1-ton pickup truck. The system was configured for
complete, unattended, remote control operation as well as for onsite support diagnostics. The AC power
was provided by a diesel generator [1].
The demonstration integrated RF antenna technology and vacuum extraction from a single,
horizontal well. The horizontal well was continuously screened over a 300-footdiorizontal section. The
antenna, approximately 17 feet long, operated at a maximum power output of 2 kW and a frequency of
13.5 6MHz The antenna was inserted to a location approximately 100 feet from the start of the screened
zone to heat one section of the well. The vacuum extraction system consisted of a rotary lobe blower
capable of providing a flow of approximately 150 cubic feet per meter (cfm) at 6 inches Hg vacuum.
Several vertical boreholes were placed both in and adjacent to the expected heat zone and in a "cold"
control zone to monitor temperatures, pressures, and soil gas concentrations. Approximately 11,000 kWh
of RF energy were successfully coupled to the subsurface sediments and heated a soil volume of nearly
1500 cubic feet to temperatures greater than 60°C. n The total volume heated to temperatures above
ambient (20°C) was calculated at nearly 30,000 cubic feet [1].
Several problems were encountered during the demonstration. Well flooding occurred due to
residual water or near saturated soil conditions in the proximity of the screen. The well flooding resulted
from heavy rainfall encountered during the first half of the test period. The system also experienced a
low vapor flow which was a result of the low permeability and high water content of the clay A vapor
lock formed down hole at the antenna from steam generated by the RF energy. Heat loss and
condensation from the gas stream through the long transition to the surface were also encountered in this
demonstration [1].
126
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Over 170 kilograms of chlorinated solvents were successfully extracted from the sediments over
the course of the demonstration. However, since the RFH system did not perform optimally, definite
conclusions as to whether the technology enhanced the contaminant extraction cannot be drawn. Results
show that any new system design should use extraction wells that are independent from the well used for
RF application. It was concluded that extraction wells could be horizontal or vertical but should be
located both within and on the perimeter of the zone anticipated to be heated by the RF antenna [1].
B.2 PILOT-SCALE TREATMENT OF SOIL CONTAMINATED WITH #2 FUEL OIL
A pilot-scale study was conducted to evaluate the ability of the KAI RFH system to enhance the
removal of #2 Fuel Oil from silty soil. The water table was located at 22.5 feet bgs and the layer of
contaminated soil extended from approximately 17.5 feet bgs to 22.5 bgs. An SVE system was in use
at the site prior to the KAI test. At the initiation of treatment, the SVE system yielded recovery rates
of thousands of gallons of oil per hour. The decrease of recovery rates to hundreds of gallons of oil per
month prompted an evaluation of the ability of RFH to enhance the SVE product recovery rates [2].
Bench-scale testing indicated that substantial oil recovery could be expected at a soil temperature
of 130°C. KAI also conducted "low-power" RF tests to characterize the soil, then designed a site-specific
RF antenna to transfer RF energy into the contaminated soil. Subsequent "high-power" tests used this
RF antenna and the existing SVE system in conjunction with KAFs 25kW, 13.56-MHz, mobile RFH
system. The RFH system was cycled on and off to maintain a temperature of 150°C or less in the
antenna borehole. The test lasted 2 weeks and 8,000 kWh of power were applied to the contaminated
soil during the test [2].
At the completion of the high-power test, the soil temperature was measured at four points within
the zone of contamination. Two feet from the RF antenna, the temperature was approximately 80°C at
19 feet bgs and approximately 70°C at 21 feet bgs. Four feet from the antenna, the temperature was
approximately 65°C at 19 feet bgs and approximately 75°C at 21 feet bgs. In addition, the fluid saturation
of the soil was measured before and after KAI's RFH test. The results of the fluid saturation
measurements, which are presented in Table B-l, appear inconclusive [2].
127
-------
Table B-l. Fluid Saturation of the Soil [2]
Depth, feet
17
19
21
22
23
24
25
Percent
Before RFH Test
NA
NA
NA
6.5
36.5
9.6
17.9
Pore Oil
After RFH Test
1.0
3.5
6.6*
6.7
21.5*
NA
1.6
Percent
Before RFH Test
NA
NA
NA
31.1
53.1
77.3
66.5
Pore Water
After RFH Test
16.6
4.7
9.0*
3.0
70.0*
NA
92.4
* Value is the average of two measurements (all other values are from single measurements).
NA = not analyzed
B.3 REFERENCES
1. Final Report: In Situ Radio Frequency Heating Demonstration. Westinghouse Savannah River
Company. Revision 0. Aiken, SC.
2. Price, S.L., R.S. Kasevich, and M.C. Marley. Enhancing Site Remediation through Radio
Frequency Heating. Preprint to be presented at the Eighth Annual Conference on Contaminated
Soils - Moving Towards Site Closures. Presented by CHESS (Council for the Health and
Environmental Safety of Soils), University of Massachusetts at Amherst, September 23, 1993.
128
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Appendix C
Vendor Claims Section
for
Innovative Technology Evaluation Report
March 1995
Prepared by
Raymond S. Kasevich David L. Faust
KAI Technologies Inc. KAI Technologies Inc.
Eastern Office Western Field Office
170 West Road, Suite 7 P.O. Box 859
Portsmouth, NH 03801 Provo, UT 84603-0859
603-431-2266 801-225-7448
Introduction to In-situ RF Heating for SVE Enhancement
The radio frequency (RF) heating (RFH) process discussed in this document is based on the
use of an antenna' technology to efficiently and specifically apply electromagnetic energy to a soil
matrix. The focused electromagnetic energy pattern from the antenna heats the soil by directly
interacting with the soil components at the molecular level. The RF energy desorbs and mobilizes the
hydrocarbon contaminants and water by a very efficient direct heating action that does not require any
soil permeability for energy propagation2. The mobilization of the hydrocarbons and water can
significantly increase the permeability of the soil matrix and in some cases can create permeability'.
Soil can be heated in a controlled manner to temperatures above 400 degrees C by RF energy.
The soil vapor extraction (SVE) process is dependent on the ambient vapor pressure of a
contaminant in the soil and the permeability of the soil. The success of the SVE process is dependent
on the flow of air through the soil matrix which is directly determined by its permeability. The
addition of heat to the soil strongly volatilizes and mobilizes the contaminants that can be removed
from the soil by the extraction air flow. The heat also increases soil permeability by the mobilization
1 Traditional RF heating technology relies on placing the material to be heated between two conductive plates or metal
rod grids that form a capacitor cell. Typically these plates are five to 15 foot square and separated by three to 20 feet,
depending on the operating frequency of the RF energy. The KAI technology uses a dipole antenna structure that resembles
a single pipe, several inches in diameter. The length is dependent on the operating frequency. Typical frequencies used for
RF heating provide for antennas ranging in length from six to 20 feet which allow for the treatment of comparable soil
thicknesses.
2 RF energy propagates easily through dielectric materials such as dry soil. Wet or hydrocarbon impregnated soils
absorb RF energy until the water and hydrocarbons are volatilized and driven from the soil. As the soil drys and is
decontaminated the RF energy passing through the soil loosing less energy and therefore more strongly heats the soil at a
greater distance from the antenna.
3 The production of from water bound in some rocks is typically adequate to cause explosive fracturing which is a
macroscopic permeability enhancing mechanism.
129
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of water and some types of contaminants. Therefore, RFH enhances two of the governing
mechanisms of the SVE process. Therefore, active in-situ RFH can be expected to dramatically
shorten the SVE system closure time and improve recovery efficiency in comparison to that of a
passive system.
Soil heating by steam or hot air injection are considered competitive processes to RFH. Both
injection techniques require a minimum level of soil permeability for successful application. Heat is
transferred into the soil by fluid propagation and thermal conduction mechanisms. Both processes
require the use of high levels of energy generation and transmission to deliver relatively low levels of
predictable heat to the subsurface environment due to significant thermal losses in the propagation
process and the uncertainty of the fluid propagation paths within the soil matrix. Steam injection is
limited to the delivery of temperatures below 100 degrees C and requires a removal and disposal
strategy for the contaminated condensate. Hot air injection does not suffer this drawback but does not
carry as high a level of thermal energy level into the formation as steam does. Both thermal injection
approaches have been shown to be of value to remediation efforts. However, neither technique
provides the precision and controlled delivery of heat that is available through RFH techniques.
Table of Contents
Comments on the Kelly Program 3
1.0 Program Summary 3
2.0 Details of the Basic RFH System 6
3.0 Review of Soil Chemical Analysis 15
4.0 Review of Soil Vapor Extraction Data 20
5.0 Cost Projections for an RFH system 23
130
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COMMENTS ON THE KELLY PROGRAM
The five sections presented here have been adapted entirely or in part from a December 1994
draft of a technical appendix4 supplied by KAI Technologies to Brown and Root Environmental.
This technical appendix was written for inclusion in the final program demonstration report to the Air
Force Center for Environmental Excellence.
1.0 PROGRAM SUMMARY
1.1 Overview
KAI Technologies, Inc. demonstrated its emerging in-situ radio frequency heating (RFH)
process at Kelly Air Force Base, San Antonio, Texas, IRP site S-l during the spring of 1994. The
technology demonstration was conducted under contract with Halliburton NUS5 under contract with
the Armstrong Laboratory. Environics Directorate, AL/EQW, Tyndall Air Force Base in cooperation
with the U.S. Environmental Protection Agency.
The primary objective of the RFH test of the KAI technology was to provide useful
information to assist the Air Force in preparing for a commercial scale demonstration of RFH
decontamination. This effort included the qualitative evaluation of vapor extraction and soil heating,
the evaluation of contaminant movement through soil, and the removal of volatile organic compounds
from the soil through the vapor stream. An important aspect of the program was to document RFH
applied with a single borehole, dipole antenna, in contrast to previous RFH testing that used a cage of
electrodes to form a capacitor heating cell.
Other important objectives of this test were: 1) validation of electromagnetic and thermal
modeling; 2) demonstration of dual heating applicator (antenna) interactions during the heating cycle
as a diagnostic tool; 3) documentation of safe near-field electromagnetic emission levels; 4)
documentation of compliance with harmonic interference levels set by the Federal Communications
Commission (FCC) for systems operating under part 18 rules.
The RFH test of the KAI technology was not a remedial action test. The soil vacuum
extraction (SVE) system test used in the RFH demonstration was an experimental design with a
number of unique operating configurations. The SVE system was operated with numerous
configurations and was not optimally designed or operated for the heating pattern developed by the
KAI heating antennas. Funding limitations did not allow the SVE portion of the RFH program to be
explored and optimized. Therefore the absolute TRPH, VOC and SVOC removal rates measured
versus the applied RF energy for this program cannot be used as statements on the effectiveness of
RFH.
j
"RF System Operating Description- Appendix to the final program report," for the report titled, Technology
Demonstration of Radio Frequency Soil Decontamination, submitted to Brown and Root Environmental for delivery under
USAF Contract No. F33615-90-D-4011, Delivery Order No. 0007, contract Project No. 3688. December 1994 Draft
submission.
5 Currently identified as Brown and Root Environmental, a Division of the Halliburton Corporation.
131
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The KAI mobile RF system was prepared and ready to start heating within six working days
of the system's arrival on site. The KAI RFH system successfully delivered 15,549 kilowatt hours of
energy to the heating zone within a total time span of 5 1.3 days The efficiency of the RF energy
transfer to the soil during the heating period exceeded 85% . These are significant operational
achievements that are prerequisites for commercial system development.
A dual antenna system was employed for this test. Measurements of mutual coupling between
antennas during the heating periods provided information on the removal trends of moisture and
contaminants. Significant changes in the mutual coupling measurements occurred during the heating
periods. Refinement of this measurement technique will be an important diagnostic and control
component of a fully automated commercial system.
The program accomplishments summarized below are from the perspective of the RFH system
operation and interaction with site conditions.
1.2 Accomplishments
• The uniformity of soil heating within test volumes - The heating program provided an
extensive data set of temperature profiles.
The initial heating rate of the test and several aspects of the SVE configuration produced
thermal records that suggest that there are significant regions of uniformity with soil
temperatures elevated well above 100 degrees centigrade (C).
There were regions, at a 3-foot radius from the antenna that exceeded 120 degrees C,
even in the context of SVE flow influences (see section 4.0 of this document). These
infrared (IR), indirect temperature profiling measurements suggested that adjacent soils
should have had localized heating temperatures for the hydrocarbons at or above the 150
degree temperature goal of the program. The highest measured temperature for the
program was a direct, peak measurement of 233.9 degrees C by a fiber optic temperature
probe located on the outside of the heating well liner wall. The sustained high
temperature readings in this region suggested a flow of a hot liquid into the volume
surrounding the well liner sensor. This indirect measurement suggested that a significant
mass of liquid was heated to a temperature in the vicinity of 240 degrees C within the
heating zone.
• Commercial Operation - The later portion of the heating program (21.3 days) provided
operating statistics that can be used for commercial system cost and operation projections.
System costs for an automated, low labor requirement, system can be developed from the
optimum operation periods of the program.
1.3 Modifications to Program Cost and Operation
This program was executed within the framework of several modifications. The most
significant are:
• The on-site heating zone was defined as one-half of the volume originally planned as the
treatment zone. This was due to the choice of a 27.12 MHZ frequency to heat two
132
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thinner, 10-foot thick, adjacent volumes faster than the 13.56 MHZ alternative ISM6
frequency. The 13.56 MHZ frequency would have required more on-site heating time
but would have covered the original, 20-foot thick treatment zone. The lower frequency
also would have extended the volume of heating influence further beyond the SVE
extraction and injection wells. Therefore, the collection efficiency of the SVE system, as
installed, would have been increased.
• The RFH applicators were positioned high in the well liner borehole spanning from 4 feet
down to 14 feet within the heating zone. Program time was not available to move the
applicator to additional heating positions.
• Initial delivery of 3-phase AC utility power to the RFH system limited the RF energy
generation rate. For the first 22 days of the program the system generated RF energy at
an average rate of 9.42kW/hr as opposed to the last 21.3 days that maintained generation
at an average rate of 19.93 kW/hour.
• The initial low power delivery rate did not allow the sequential heating of boreholes Al
and A2 in a manner that would allow their heating patterns to overlay as an
approximation of a dual applicator, dual RF generator system operated as a phased array.
• The design of the SVE system prevented meaningful conclusions being drawn about the
measured changes in TRPH VOC and SVOC concentrations inside and outside the
treatment zone as a result of RFH treatment.
1.4 Conclusions
Site set-up time was relatively fast and efficient with a 2-person KAI field team. The KAI
mobile RF system performed as expected and provided significant RF energy coupling to the soil.
The applicator system (antennas) allowed for flexibility in the in-situ application of RF energy at
selected depths. The coupling efficiency or energy transfer to soil surrounding the antennas was high
(> 85%). The application of energy to the heating zone increased the permeability of the zone bya
factor of more than 207. This result has significant implications for commercial RFH systems
operating with tight soils. SVE efficiency appeared to increase substantially during the demonstration
period.
* ISM is an abbreviation for the Industrial Scientific and Medical frequencies authorized for RF heating under the part
18 regulations of the Federal Communications Commission.
7 This is believed to be a conservative number. Factors of 50 can be derived from the data set but SVE conditions are
not directly comparable for all calculations.
133
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2.0
DETAILS OF THE BASIC RFH SYSTEM
The KAI RFH system is mobilized as a self-contained field unit with work space and storage
capability to support two heating applicators. Figure 1 is a side view of the mobile system. The
overall length is 52 feet and 2 inches with a trailer bed length of 28 feet. Figure 2 outlines the
component groups of a basic radio frequency (RF) heating system. The system power is supplied
from the local utility power grid or a diesel generator through the 3-phase power distribution panel.
The panel supplies power to the RF generator and a cooling blower as well as lighting, air
conditioning and instrumentation. The power system also includes an uninteruptable power supply for
critical instrumentation and control functions. The RF Generator supplies power through the
transmission lines and the matching network to the RFH applicator or "antenna" which typically
radiates 95% of the energy it receives into the surrounding medium (soil, rock, oil).
The system controller is interfaced to all elements of the system. Site environmental monitors
can detect overheated components, energy leakage and component tampering. The controller is
capable of transferring the complete monitoring of the system to a remote location through a phone
line or a cellular telephone data link.
Alarms and system status messages can be set via the telephone link or messages can be sent
as pre-recorded voice segments via the same UHF radio frequency transceiver used for site
communications. On-site diagnostics instruments periodically measure the system's performance and
verify operation.
1 Mobile RF heating system with removable instrument shelter, storage trailer and a utility tow
vehicle.
Figure 3 shows the switched, dual applicator configuration that was used for the Kelly
program. The RF generator is connected alternately to applicator #1 and applicator #2 under
computer control.
134
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Vi ER
'T«'(.JTiQN
PHONE LINE
! CONTROLLER DIAGNOSTICS
—I
f J
ENVIRONMENTAL
MONITORS;
• MATCHING NETWORK
/—TRANSMISSION LINE
'
HEATING PATTERN
2 Block of an RF
135
-------
INSTRUMENT SMELTER
• TRANSMISSION UN£
r
1
ORO'UNO PLANE
{AS REQUIRES)
APPLICATOR |1
APPLICATOR |2
3 Him k iiai'i jin )i a >t, t.:f«
-------
4 lljn view of the RF heating trailer and applicators as configured for the Kelly
progiam tests.
Instrument Shelter:
Trailer:
8 ft. x 8 ft. x 20 ft. insulated steel utility shelter with HVAC and AC power
distribution. The unit features an air-shock isolation rack configured to
protect the 25 kW RF generator cabinet and an instrumentation and control
rack. The shelter also has a filtered air system to cool the RF generator.
A 28-ft flat bed trailer a with neck mounted deck and steel shelter is used to
transport the shelter. The trailer includes a heat exchanger tank and cooling
fluid circulation system for a 25 kW dummy load which is used to setup and
test the RF generator. The under deck area also contains four 28-foot
applicator storage bays. A typically loaded trailer weighs 20,000 Ibs.
137
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Truck: A heavy-duty pickup truck modified for operation with the trailer as a 30,000
Ib. GCVW combination highway vehicle mobilizes the system. The truck
frame also carries a roof rack system suitable for transport of applicator
assemblies of up to 30 feet in length and emplacement tower sections. The
truck is used for general site support tasks during a heating program.
2.1.2 Kev System Components Within the Instrument Shelter
These components are listed by generic names in the block diagrams of Figures 1 and 2.
AC Power panel: The shelter is equipped to accept 3-phase 208 to 240 VAC power from a utility
or Diesel generator source. The shelter has a 3-phase 200 Ampere power panel
(WYE and DELTA feed options). The lines are metered with two levels of
transient and surge/over-voltage protection. The system also has a 1-phase 100
Ampere, 110/220 VAC panel that is powered from a 3-phase WYE service or a
separate 1-phase feed. The 1-phase power distribution system includes a 1 KVA
uninteruptable power supply (UPS) to protect critical control and data acquisition
functions. The 1-phase panel also controls power for the auxiliary cooling
blower of the RF generator as well as for the air conditioning and lighting of the
shelter.
RF Generator: RF Power Products model 25,001D generator (built to KAI specifications and
with KAI operation and control modifications). Designed for operational
compliance under Part 18 of FCC regulations for Industrial, Scientific and
Medical (ISM) equipment.
Frequency: 27.12 or 13.56 MHZ operation (crystal controlled)
Emission: AO (CW unmodulated)
output: 25,000 Watts, tuned output stage (harmonics suppressed)
The output is continuously adjustable from 100 to 25,000 Watts,
the maximum power is set by the line voltage of the site's 3-
phase power service.
Details: The generator was operated at 27.12 MHZ for this program. The
unit is an optimized industrial design with a 3CX15000A7
ceramic vacuum tube output stage and automatic power controls.
The modifications include interfaces for remote control and
function monitoring.
Matching Network: KAI custom design with proprietary features.
(Tuner)
Frequency: design centers of 13.56 MHZ and 27.12 MHZ for specified
impedance transformations.
Power: > 25,000 Watts
138
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Controller:
Details: "T" network design with input and output ports using fully
shielded 1-5/8" EIA connections to rigid line coax. The unit
contains motorized input, shunt and output controls and interfaces
to a KAI control and tuning software package.
This is function is developed by the integration of a number of commercial
components.
Computer: Industrial Computer Source rack mounted system with 80386 and
80387 processors, 8 MB RAM, 240 MB hard disk with GPIB and
modem interfaces.
Software: The data acquisition software is a customized and proprietary
package of capabilities developed for real time control and
specialized diagnostic measurements.
Switching: HP 3488A switch controller with five interface modules to
provide contact closures, coaxial switching and TTL sensing/logic
interfaces. The unit is interfaced to the RF generator, tuner and
RF switches as well as system annunciators and safety monitors.
Diagnostics:
Communications with the system is via a high speed error
correcting FAX/modem suitable for wireline or cellular
communications. The unit is capable of sending a data message
to a host computer, a digital display radio pager or a FAX
machine. The system also communicates via a UHF radio data
voice message link to signal the operators hand held radio or
scanner of a system status message.
This function provided by a number of commercial components. The items
listed here acquire data that is logged by the control computer in a data
acquisition mode. Software setup files define if a channel is to be used for
control processing for limit alarms, warning or control actions.
Sensing: Two HP 3457A scanning digital multimeters (DMM) with 22
input channels are used to monitor system voltages, temperatures,
pressures, and power levels
Temperature: Luxtron 790 floroptic thermometer using four fiber optically
coupled sensor probes to monitor the Heating Zone.
AC Power: Ohio Semitronics PC5 and MVT 3-phase Wattmeter and Voltage
transducers interfaced to the HP3457A DMM.
Vector HP 8508A with frequency coverage from 0. 1 to 2000 MHZ with
Voltmeter: a phase locked sensing channel sensitivity of down to 10 uV (-87
dBm).
139
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Signal HP 8656B with coverage from 0.1 to 990 MHZ and output levels
Generator: of up to + 13 dBm.
Network HP 3577B network analyzer with 0.1 to 200 MHZ coverage with
Analyzer: an HP 35677A S-parameter test set.
TDR: Tektronix 1503C time domain reflectometer
Megger: Biddle model 218650CL with 500 to 5,000 VDC test voltages.
Environmental These items are used to measure site conditions, above and below ground. The
monitors: isotropic probe is used to monitor site safety conditions for USAF ad OSHA
compliance. The spectrum analyzer is used to measure RF harmonic emissions
for FCC compliance.
Spectrum Analyzer: HP 8591E analyzer with EMC personality modules.
Biconical antenna: EMCO 3104A calibrated antenna and insulated tripod.
20 to 200 MHZ calibration.
Isotropic probe: Holiday model HI-3012 with MSB and HCH probes.
A foam spacer ball for 0.1 m near contact
measurements (FCC defined specification).
Thermocouple
readout/calibrator: Omega CL 23 type T digital readout used for all on
site temperature measurements of thermocouples.
Weather: Davis Instrument Weather station II with dewpoint and
rainfall sensors.
IR Probe: Omega model OS36-T-240 passive IR thermocouple
unit with type T output mounted on a PVC extension
probe.
2.1.3 Key System Components Outside of the Shelter
These components are listed in the diagrams of Section 2.1. The use of these components
will vary greatly with the site configuration.
Transmission lines: 1-5/8" rigid copper coaxial lines were used throughout system for system
interconnections and to transfer power to the heating antennas. The transmission
lines were pressurized with 5 to 15 PSI nitrogen and delivered power to either,
heating antenna through a computer controlled, motorized RF switch. Delivery
of power to the antenna is typically > 98% efficient for these transmission
components.
140
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RF Switch #3:
Applicators:
Guide tubes:
(Sleeves)
Ground planes:
Towers:
Dielectric model A 50000-203, pressurized, heated, 1-5/8" EIA flange
connections. The switch is housed in a weatherproof, secure housing with
adjustable legs and universal joints on each of the ports connections.
Two KAI 3.5" antenna assemblies designed for subsurface RFH applications
(KAI-0690-30).
Frequency: design centers of 13.56, 27.12 or 40.68 MHZ can be configured.
Power: 25,000 Watts
Diameter: 3.5" OD w/o centralizing spacers
Length 7.38' to 11.38' span set for soil conditions (27.12 MHZ)
VSWR: Set by adjustments of length, typically < 1.5, working max is set
by the power level, frequency and nitrogen pressurization level.
Feedline: 1-5/8" EIA flange
Details: The antennas are adjustable length, dipole-type, end-feed
structures with 1-5/8 in. EIA feedlines. The standard design
employs aluminum radiating elements with Teflon insulating
components. The use of Teflon limits its to operation to an
ambient temperature of 200 degrees C (392 deg. F). Operation
can be extended above this temperature by the use of ceramic
insulating components and/or localized cooling of the applicator
assembly by compressed air.
The applicators were vertically emplaced in a vertical boreholes lined
with 4.5 inch ID high temperature fiberglass liners. The liner wall thickness was
nominally 0.25 in. and the outside diameter was 5 inches.
The antenna counterpoise/ground plane at the soil surface consists a 8 ft. x 22 ft.
x 0.062 in. expanded aluminum mat pattern mat, extended around and between
the 3 ft. x 3 ft. x 0.25 ft. thick aluminum ground plane base plates are located
around each borehole sleeve liner. An 18 ft. diameter pattern of twelve
aluminum radials of #2 insulated aluminum cable extend from each base plate.
The perimeter cables are terminated to form an 18-foot diameter aluminum
radial pattern of #2 Aluminum cable terminated by 5/8 inch OD x 4 foot copper-
clad steel ground rods driven about 45 inches into the soil. The radials are
centrally capped by an aluminum screen mat that is bonded to the radials. The
antenna transmission lines and supporting structures are bonded to the ground
plane at multiple points. NOTE: This structure can be simplified for many
installations and could have been in this case since the electromagnetic emission
levels were well below all safety and harmonic emission requirements.
The emplacement towers are mounted to the 3 ft. x 3 ft. aluminum base plates.
The towers are constructed from 10-foot lengths of aluminum antenna mast
sections. The masts are jointed to form 10 ft., 20 ft. or 30 ft. emplacement
towers. The towers are supported with four aluminum extension tubes with
anchored base pads suitable to make the towers self supporting without the use of
guy lines. The complete tower includes a 1,500 Ib. winch and two rope pulley
lines.
141
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3.0 REVIEW OF SOIL CHEMICAL ANALYSIS
Adapted from section 7.0 of the KAI appendix to the Brown and Root report.
The soil chemical analysis scheme was originally based on the definition of a treatment zone
volume of 111 cubic yards (15 ft. x 10 ft. x 20 ft.) which was compared to a control sample region
bounding the sides of the volume with sample depths of up to 10 feet below the region. The soil
analysis for Total Recoverable Petroleum Hydrocarbons (TRPH) was based on the analysis of 40
sample pairs within this region.
Due to changes in the heating system configuration, a heating zone of 15 ft. x 10 ft. x 10 ft.
was defined inside of the treatment zone. The top of the zone starts at a depth of 4 feet and ends at a
depth of 14 feet. This zone was further subdivided for analysis into two halves. The halves are
centered about each of the heating wells (Al and A2). Figure 5 is an isometric view of the zones
with the heating applicator wells (Al and A2) and the screened S VE wells (El to E8). Note that the
open, non-black, regions of the SVE well representations are screened sections of pipe that allow air
input or extraction from the treatment zone. Figure 6 is a similar view with the monitoring wells (Fl
to F5) shown in addition to the heating wells and three of the temperature monitoring thermocouple
strings (TC-1 to TC-3).
5 Isometric view of applicator and SVE wells with piping.
142
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TC-3
HEATING
ZONE
TREATMENT
ZONE:
i Isometric view of applicator monitoring wells.
The TRPH analysis of these zones, with a > 80% confidence level correlates with the energy
to the and the period of the applied energy (heating).
Treatment Zone
Heating Zone
Volume
(en. yds)
111
55.5
TRPH
(%)
29
49
Energy
15,549
15,549
Days Spanned
49,92
49.92
Heating Zone by Applicator, Al + A2 == Heating Zone Volume
,.
Al Beating Zone
A2 Heating Zone
27,7
27.7
NA
44
4,348
11,201
8.15
41.77*
2 spans, 28.9 and 1.2,87, with a cooling period between cycles.
143
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The A2 heating zone, driven by applicator #1, is suggestive of an anticipated recovery rate
for the energy applied. Ideally this zone and the Al zone would have each received 10,000 KWH in
a 42 day period. It is projected that this type of heating program would have been more effective
than the slow heating period with cooling cycles that this sequence experienced. It is also expected
that if a second generator were used, the simultaneous, phased-array heating would have produced an
even stronger and more rapid heating effect that would have further improved recovery. Finally,
changes to the SVE system design would also be a source of significant recovery improvement.
3.1 Impact of Changes in the Heating System Configuration
Changes in the heating program's planned operating time and its ISM operating frequency
required that the heating zone be defined as approximately the upper half of the treatment zone. This
change occurred when an ISM operating frequency of 27.12 MHZ was chosen in contrast to a 13.56
MHZ frequency. The 27.12 MHZ frequency was chosen to allow a faster heating of two smaller
adjacent volumes within the treatment zone as opposed to a larger heating zone with a slower heating
rate.
The 13.56 MHZ applicator would have had a nominal heating span of 18 feet, as opposed to
the 9 foot, span of the 27.12 MHZ applicators and could have been positioned within the center of the
treatment zone. Two, more rapidly heating, 27.12 MHZ applicators were chosen to be driven in a
time-multiplexed heating mode by a single 25 kW RF generator to approximate the performance of a
more optimally configured dual RF generator system. This configuration allowed data to be gathered
that would be predictive of how a dual RF generator phased-array* RF system might perform.
A additional impact of the thinner, vertical profile, heating span occurred when the applicator
was fixed in the upper half of the treatment volume. This upper half favored the heating of VOCs as
opposed to SVOCs in the lower half of the treatment zone.
3.2 Other Operating Details With Soil Analysis Influence
The SVE system typically operated in a "deep extract on" mode that pulled vapors down from
the bottom of the heating zone into the extraction wells screened from 10 ft to 20-ft. depths (see
Figure 5). The effect of this downward vapor "draw" may be responsible for some contaminant
migration from the heating zone into the treatment zone and is likely to make it difficult to
quantitatively evaluate contaminate concentration changes.
Several of the statistically defined TRPH sample sets were complete enough at test well
locations to be examined as a concentration profile. A review of some TRPH sample sets suggest that
contaminants condensed between the 0-foot and 4-foot levels where the SVE efficiency was low.
Condensation also appears to have occurred where soil heated and cooler ambient soil air mixed near
the screened entrance to an extraction well. The following data listings are of three sets of soil
samples. Missing depths were due to the statistical sampling scheme used to distribute the 40 sample
pairs, no data exists at these points.
* A 2-element phased applicator array actually has a heating rate and intensity advantage over what can be produced by
two, non-phase-controlled applicators and RF generators. This testing approach provided data to evaluate how well the base
heating rate could be predicted for the non-phased applicators. The test also demonstrated the electromagnetic field coupling
levels that could be achieved between the two applicators.
144
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A2 - Location- of applicator #1 with the majority of applied energy — The 0 to 4
foot locations show significant increases in concentration. The heating zone volume
near the applicator shows a strong removal trend. The 10 to 12 foot location that
corresponds to the highest heating temperature profile shows significant removal.
Location A2
Pretreatment
Concentration
(ppm)
0-2ft. 2,330
2-4ft. 203
heating zone boundary —
4- 6ft.
6- 8ft.
8- 10ft.
10-12 ft.
12 - 14 ft.
622
1,530
1,290
106
heating zone boundary —
14-16 ft.
16-18 ft.
18-20ft
79,700
39,300
Post treatment
Concentration
(ppm)
8,850 [suggested condensation]
2,570 [suggested condensation]
154
33.3 [removal to quantitation limit]
20,800
28,300 [removal by ambient air SVE
only]
E5 - Extraction well located on center line near A2 — Extraction is enhanced in the
heating zone. The 12 to 14 foot level appears to a condensation boundary were cool
air meets the downward flow of hot vapor.
Location E5
Pretreatment
Concentration
(ppm)
0-2ft.
2-4ft.
heating zone boundary —
4-6ft. 2,710
6-8ft. 1,530
8-10 ft.
10-12 ft. 668
12 - 14 ft. 739
heating zone boundary —
14-16 ft.
16-18 ft.
18-20ft
105,000
Post treatment
Concentration
(ppm)
673
587
330
1,450 [suggested condensation at
extraction well]
35,800 [removal by ambient air SVE
only]
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F3 - Monitor hole for IR temperature profiles centered between Al and A2 at 5
feet — Strong removal is suggested in the top of the heating zone where the maximum
temperature profiles were recorded between 6 and 10 foot. The temperature dropped
off sharply in the 10 to 12 foot zone and could be seen to match the region of
increased concentration.
Location F3
Pretreatment
Concentration
(ppm)
Post treatment
Concentration
(ppm)
0-2ft.
2-4ft.
heating zone boundary —
4-6ft. 4,920
6-8ft.
8-10 ft.
10-12 ft. 336
12 - 14 ft.
heating zone boundary —
14-16 ft.
16-18 ft.
18-20ft
702 [strong removal suggested]
4,510 [suggested condensation between
extraction wells screened from
10ft. to 20 ft]
4.0 REVIEW OF SOIL VAPOR EXTRACTION DATA
Adapted from section 8.0 of the KAI appendix to the Brown and Root report.
The soil vapor extraction system flow characteristics do not appear to have been optimum to
extract from the chosen heating zone in the upper level of the site treatment zone (see screened well
configuration shown in Figure 5 of Section 3.0 of this document). However, it appears that they
were adequate to demonstrate significant VOC removal from the heated zone.
The downward "draw" of the SVE system on the heated zone has been observed to produce a
number of thermal profile measurement distortions that require careful analysis for interpretation. In
general, the downward flow caused the deep portions of the thermal patterns to have lower relative
temperature values and truncated profile patterns with minimal lateral flow and limited "draw" from
the higher levels of the zone. It is also very possible that condensation occurred for some volatiles as
they mixed with cooler air as they were drawn to the extraction wells.
The SVE system output temperatures, measured at the control valves next to the vacuum
manifold, were generally lower than anticipated. Temperatures within the heated zone suggested that
the high temperature soil vapors could be estimated to range from 100 degrees C to well over 180
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degrees C (+230 degrees is likely). These vapors were mixed with a significant volume* of cool
subsurface air that maintained the extraction well output temperatures well below 100 degrees C (as
measured by average reading temperature probes).
Figure 7 is a simplified representation of the conditions within the RFH zone. The sensor
well is a monitoring well such as Fl which was located three feet from a heating applicator well.
The RF energy incident on the soil from the heating antenna directly interacts10 with water droplets,
hydrocarbon deposits and sand represented in this figure. The RF interaction causes each of these
items to heat as an isolated point source. The heating rates differ for each of the items. At a given
point in the heating program the hydrocarbon deposit points my be heated to a temperature of perhaps
200 degrees C while the water droplets are just approaching 90 degrees C. The sand at this point
may only be heated 5 degrees above an ambient temperature of 23 degrees C to perhaps 28 degrees C
(unless the sand particle has a hydrocarbon or water droplet on its surface and it then is heated by
conduction to a higher average temperature).
The underground SVE air flow pattern draws ambient, 23 degree C, soil air into the heating
zone. The RF illuminated soil heats the 23 degree ambient air passing through the soil matrix to a
higher temperature. However, this temperature is still well below the highest point source
temperature of 200 degrees Cfor this example.
In Figure 7 the soil-heated air flows past the fiberglass wall of the sensor well. The air heats the wall
to a temperature that approximates that of the air but is typically much lower in temperature than the
point sources that heated the air. The probes within the sensor well measure the wall temperature.
The infrared (IR) probe is the most accurate measurement since it optically focuses on a small spot
and does not average its thermal mass with that of the contact point on the wall. This kind of probe
is best for rapid temperature profiling but does not provide and absolute measurement of the average
wall temperature. Movement of the probe mixes air within the well and further diminishes the
absolute accuracy of the measurement. The contact probe can provide more accurate measurement of
the wall temperature if the volume behind the probe is filled with a barrier that stops air from flowing
near the probe. The probe needs to be in contact with the wall in excess of 5 minutes to obtain an
accurate reading.
It is important to note that for the Kelly program, all of the sensor wells were also surrounded
with 0.5 to 2 inches of dry sand. This sand layer further separated the fiberglass wall from the
heated soil matrix and enhanced the air flow in this region. It is on this basis that all ZR temperature
measurements were considered low by a conservative 10 to 20 degrees and in reality may have been
40 to 100 degrees below the actual point source heating temperatures.
9 This conclusion is arrival at by estimating that the top 1/3 of each extraction well (1,0 ft. to 13 ft, ) received hot
vapors and iiws balance of the well (13 ft. to 20 ft.) contributed cooler subsurface air to the extracted air stream. In cases
'where multiple extraction wells were connected, the dilution ratio was still higher.
w Radio frequency (RF) energy desorbs and mobilizes the contaminants more effectively than heat conduction by steam
or hot air because thermal activation of the contaminant occurs al the molecular level throughout the RF treatment volume.
The dipoie-dipoie bonding between contaminant molecule and soil particle is thermally agitated at the bonding site by the RF
energy,
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TO
METER
CONTACT
TEMPERATURE
PROBE
IR
OPTICAL
PROBE
FOCAL PATTERN
OF IR SENSOR
SENSOR WELL
SOIL HEATED
BY RF ACTION ON
HYDROCARBONS AND WATER
HYDROCARBON
SAND
PARTICLE
WATER
DROPLET
— FIBERGLASS
WALLS
(WELL LINER)
7 Simplified diagram of indirect temperature measurements of soil temperature in the heating zone
under SVE influence.
11
The peak measured temperature of 233.9 degrees C by a point sensor on the outside of a
fiberglass well liner suggested that a hot liquid flowed into the vicinity of the sensor and blocked all
air flow into the region of the sensor. The liquid zt>0s heated to a temperature of perhaps 240 degrees
or more within the heating zone near the sensor well. This is likely to be the temperature of many of
the isolated hydrocarbon contaminant heating sites distributed throughout the heating zone.
There is are three important trends to consider in interpreting temperature data for this
program.
Increasing permeability increases air flow and lowers measured temperatures - When
contaminants and water are removed from the region surrounding the heating applicator
wells, the permeability of the soil increases. Increased permeability increases the SVE
air flow volume within the heated region. This trend lowers the measured temperature in
the monitoring wells due to increased flow and air mixing.
11 This peak was part of a slow trend that stayed above 200 degrees for several hours for this well and corresponded in a
high reading at an adjacent well sensor at the same depth.
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Contaminant removal lowers the heating rate near sensor well regions - As water and
RF heated contaminants are removed from the heating zone near the applicator wells and
the sensor wells, the heat generation rate drops to a lower "sand-like" heating rate. The
regions with removed contaminants become somewhat "cooler" than the regions on the
outer boundaries of the heating pattern that continue to have strongly heating
contaminants.
The expansion of the heating pattern beyond the sensor wells will lower the
measured temperatures at the interior well locations - The increased permeability,
contaminant/water removal, increased available soil air mixing volume and the increasing
distance of the heating front from the sensor wells may all contribute to the measurement
of lower relative temperatures as the heating program progresses.
5.0 COST PROJECTIONS FOR AN RFH SYSTEM
Adapted from section 9.0 of the KAI appendix to the Brown and Root report.
The Kelly RFH program was essentially executed as an investigative pilot program that
addressed a number of site configuration items (e.g. SVE) in addition to the RFH system installation
and operation. The site was operated with more personnel than would normally be required for even
a larger heating site. The program and site conditions did not allow for the progressive expansion of
the heating zone or full automatic operation of the heating system. These two factors make it difficult
to directly scale the costs of the Kelly program to a commercial embodiment of an RFH system.
However, there are some cost and resource utilization numbers available, directly from the
program data, that can be used to generally characterize the application of RFH for thermally
enhanced SVE programs. These numbers were based on the last 21.3 day period12 of the heating
program. These planning numbers are:
• RF Energy Generation rate: 19.93 kW/hour
This rate is dependent on the available
3-phase AC utility voltage level. AC line
voltage set a 22 kW peak power operating
level for this site.
• Cost per hour of RF generated: $3.88/hour
This cost is based on a 19.93 kW/hr
generation rate with a 58.9% system 3-phase
AC power conversion efficiency plus 5 kWh
overhead with a utility rate of $0.10/kWh.
• RF system operation within on-site span: 94.54%
This operation period includes breaks
for measurements and maintenance checks
over a span of 10 days or more.
12 This period follows the repairs to the 3-phase power system splices and replacement of the power line.
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5.1 Outline for Costing of a 200-kW System
A 200-kW system could be developed by using eight 25-kW RF generators with the capability
of driving either 2-element or 4-element applicator arrays. The system would employ a minimum of
16 switched applicator positions to allow continuous operation of the system as applicators are
removed from heated areas and installed in new areas. The exact definition of a 200-kW system will
depend on the site characteristics. Some of the principal determinates of the system configuration
would be:
• Contaminant plume thickness, extent and nominal depth defines if the preferred access is
through either vertical or horizontal drilling techniques.
• The preferred heating dimensions of the plume will determine if the RFH system's
operating frequency should be 13.56 MHZ with a nominal heating span of 18 ft. or 27.12
MHZ with a nominal span of 9 feet. It is also possible to operate with a 6 foot span if a
40.68 MHZ frequency is used. In some cases the heating rate of the plume will be a
factor in contrast to SVE flow requirements. An ISM heating frequency of 40.68 MHZ
heats the smallest volume most rapidly and 13.56 MHZ heats the largest volume more
slowly.
• The need or option to access large volumes of the contaminant plume also determines if
the system needs large numbers of installed applicators with switching networks to allow
efficient, automated operation. Alternately a limited number of applicators, with
computer controlled mechanical positioning equipment, can incrementally heat large
volumes of the plume from a few boreholes (e.g., horizontal).
5.2 A 200-kW System Description
The following system would be defined as a wide coverage 13.56 MHZ system configured for
horizontal drilling emplacement. It would have the following components:
2 RF Master control and instrument trailers with an internally mounted 25 KW, 13.56
MHZ RF generator and tuner (the units would be similar in size and design to the KAI
pilot Rig #1 used for this program). Each master control trailer would also carry control
and diagnostic instrumentation. The master control systems would be linked with the
slave systems through fiber optic cables. Each master control system would be fully
automated and respond to both local and remote control computer commands.
2 Slave RF systems with three 25 kW, 13.56 MHZ RF generators and tuners per trailer.
Each slave trailer would include a common cooling system and 3-phase AC power
distribution system. Flexible and rigid RF transmission lines suitable for the operating
frequency would be used to reach the 16 heating locations from the two trailer groups of
master and slave units.
16 Flexible horizontal applicators with an emplacement system allowing controlled motion
during heating of up to 45 ft. per setup.
8 Motorized RF switches to select between two installed applicators that are to be selected
by each RF generator/tuner group.
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1 3-phase AC power utility or Diesel generator service capable of providing a minimum of
500 kVA for the site. Additional power requirements would dependent on the
requirements of the SVE and off gas treatment systems.
A heating system of this scale and capital investment13 can be expected to operate in the field
with utility power costs, full automation, and programmed personnel support for configuration
changes at a cost of much less than $100 per cubic yard over a multi-year operating period. This
figure is exclusive of horizontal drilling costs, SVE system installation, off gas treatment and non-RF
site operating costs.
5.3 Recommendations on System Strategies
The costing of RF thermally enhanced SVE programs is very dependent on the use of the
following key strategies:
• Select the ISM heating frequency based on the optimum heating rate, soil penetration
depth, and contaminant thickness.
• Select a drilling technique (vertical, slant or horizontal) that provides the most access to
the contaminated zone for each borehole position and applicator heating span.
• Use each heating applicator in multiple positions along the length of the guide tube or
slowly "scan" the heating zone with the applicator's heating span.
• Use each RF generator to sequentially drive two or more applicators.
• Use multiple RF generators in groups of two or four as phased arrays to focus and steer
the heating pattern.
• Use automated and remote control operation to minimize the need for highly skilled on-
site labor.
The application of RF thermal enhancement also needs to be characterized in terms of the
time savings it represents over conventional treatment projections using non-thermal SVE technique at
the same site (assuming the targeted contaminants are removable on a realistic time scale by non-
thermal methods). Key points for consideration are:
• RF thermal enhancement can be applied as a rapid response tool for stopping the
migration of contaminant plumes at depths of over 750 feet.
• RF thermal enhancement may be selectively applied to high concentration, "hot spot"
regions within a general site remediation strategy using passive SVE, bio-venting or bio-
remediation.
• Thermally enhanced SVE may allow extraction of contaminates from some sites that
normally would require excavation.
13 Assuming a 5 year pay pack period.
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