EPA 542-R-97-009
PB97-177562
July 1997
Remediation Case Studies:
Soil Vapor Extraction and Other
In Situ Technologies
VOLUME 6
Federal
Remediation
Technologies
Roundtable
Prepared by the
Member Agencies of the
Federal Remediation Technologies Roundtable
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Remediation Case Studies: Soil
Vapor Extraction and Other In
Situ Technologies
Volume 6
Prepared by Member Agencies of the
Federal Remediation Technologies Roundtable
Environmental Protection Agency
Department of Defense
U.S. Air Force
U.S. Army
U.S. Navy
Department of Energy
Department of Interior
National Aeronautics and Space Administration
Tennessee Valley Authority
Coast Guard
July 1997
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NOTICE
This report and the individual case studies and abstracts were prepared by agencies of the U.S. Government.
Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty,
express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not
infringe privately-owned rights. Reference herein to any specific commercial product, process, or service by
trade name, trademark, manufacturer, or otherwise does not imply its endorsement, recommendation, or
favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein
do not necessarily state or reflect those of the U.S. Government or any agency thereof.
Compilation of this material has been funded wholly or in part by the U.S. Army Corps of Engineers and the
U.S. Environmental Protection Agency under USAGE Contract Number DACA45-96-D-0016 to Radian
International LLC.
11
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FOREWORD
This report is a collection of six case studies of soil vapor extraction or
associated technologies and three case studies of other in situ technologies (frozen
barrier containment, sonic drilling, and fracturing) prepared by federal agencies. The
case studies, collected under the auspices of the Federal Remediation Technologies
Roundtable, were undertaken to document the results and lessons learned from early
technology applications. They will help establish benchmark data on cost and
performance which should lead to greater confidence in the selection and use of cleanup
technologies.
The Roundtable was created to exchange information on site remediation
technologies, and to consider cooperative efforts that could lead to a greater application
of innovative technologies. Roundtable member agencies, including the U.S.
Environmental Protection Agency, U.S. Department of Defense, and U.S. Department of
Energy, expect to complete many site remediation projects in the near future. These
agencies recognize the importance of documenting the results of these efforts, and the
benefits to be realized from greater coordination.
The case study reports and abstracts are organized by technology in a
multi-volume set listed below. Remediation Case Studies, Volumes 1-4, and Abstracts,
Volume 1, were published in March 1995, and contain 37 case studies. Remediation
Case Studies, Volumes 5 and 6, and Abstracts, Volume 2, were published in July 1997,
and contain 17 case studies. These 17 case studies cover recently completed full-scale
remediations and large-scale field demonstrations. In the future, the set will grow
through periodic supplements tracking additional progress with site remediation.
Remediation Case Studies, Volume 1:
Remediation Case Studies, Volume 2:
Remediation Case Studies, Volume 3:
Remediation Case Studies, Volume 4:
Remediation Case Studies, Volume 5:
Remediation Case Studies, Volume 6:
Abstracts of Remediation Case Studies,
Abstracts of Remediation Case Studies,
Bioremediation, EPA-542-R-95-002; March 1995;
PB95-182911
Groundwater Treatment, EPA-542-R-95-003; March 1995;
PB95-182929
Soil Vapor Extraction, EPA-542-R-95-004; March 1995;
PB95-182937
Thermal Desorption, Soil Washing, and In Situ
Vitrification, EPA-542-R-95-005, March 1995;
PB95-182945
Bioremediation and Vitrification, EPA 542-R-97-008, July
1997; PB97-177554
Soil Vapor Extraction and Other In Situ Technologies,
EPA 542-R-97-009, July 1997; PB97-177562
Volume 1: EPA-542-R-95-001; March 1995
Volume 2: EPA 542-R-97-010, July 1997;
PB97-177570
111
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Ordering Information
These documents are available free of charge by fax or mail from NCEPI
(allow 4-6 weeks for delivery), at the following address:
U.S. EPA/National Center for Environmental Publications and
Information (NCEPI)
P.O. Box 42419
Cincinnati, OH 45242
Fax Number: (513)489-8695
Phone Verification: (513) 489-8190 or
(800) 490-9198
In addition, the case studies and case study abstracts are available on the
internet through the Federal Remediation Technologies Roundtable (FRTR) home page
at: http://www.frtr.gov. The FRTR home page provides links to individual FRTR
members' home pages, and includes a search function. Case studies and abstracts
prepared by EPA are also available through EPA's Cleanup Information Bulletin Board
System (CLU-IN BBS). CLU-IN BBS is available through the internet at
http://clu-in.com, or via modem at (301) 589-8366 (8 Data Bits, 1 Stop Bit, No Parity,
VT-100 or ANSI; Voice help: (301) 589-8368). Case studies prepared by the U.S.
Department of Energy (DOE) are available through the internet, on the Office of
Science and Technology home page, at http://em-52.em.doe.gov/ifd/ost/pubs.htm, under
Innovative Technology Summary Reports. Individual Reports prepared by DOE are
available to DOE and DOE contractors from the Office of Scientific and Technical
Information, P.O. Box 62, Oak Ridge, TN 37831; or to the public through the U.S.
Department of Commerce, National Technical Information Service (NTIS), Springfield,
VA 22161 ((703) 487-4650).
IV
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TABLE OF CONTENTS
Page
FOREWORD iii
ORDERING INSTRUCTIONS iv
INTRODUCTION 1
SOIL VAPOR EXTRACTION CASE STUDIES 7
Soil Vapor Extraction at the Basket Creek Surface
Impoundment Site, Douglasville, Georgia 9
Soil Vapor Extraction at the Sacramento Army Depot
Superfund Site, Burn Pits Operable Unit, Sacramento,
California 39
Soil Vapor Extraction at the Sand Creek Industrial
Superfund Site, Operable Unit No. 1, Commerce City,
Colorado 73
ENHANCEMENTS/ADDITIONS CASE STUDIES 109
In Situ Enhanced Soil Mixing, U.S. Department of
Energy, X-231B, Portsmouth Gaseous Diffusion Plant,
Piketon, Ohio Ill
Flameless Thermal Oxidation at the M Area,
Savannah River Site, Aiken, South Carolina, in
Cooperation With the U.S. Department of Energy Oak
Ridge Operations . 141
Six Phase Soil Heating at the U.S. Department of
Energy, M Area, Savannah River Site, Aiken, South
Carolina, and the 300-Area, Hanford Site, Richland,
Washington 165
OTHER IN SITU TECHNOLOGIES 195
Hydraulic and Pneumatic Fracturing at the U.S.
Department of Energy Portsmouth Gaseous Diffusion
Plant, Ohio, Department of Defense and Commercial
Sites 197
NRJ-100
0414-02.nrj
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TABLE OF CONTENTS (Continued)
Frozen Soil Barrier Technology at the SEG Facilities,
Oak Ridge, Tennessee in Cooperation with U.S.
Department of Energy Oak Ridge Operations
ResonantSonic Drilling
Page
. 215
. 233
NRJ-100
0414-02.ni]
VI
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INTRODUCTION
Increasing the cost-effectiveness of site remediation is a national priority.
The selection and use of more cost-effective remedies requires better access to data on
the performance and cost of technologies used in the field. To make data more widely
available, member agencies of. the Federal Remediation Technologies Roundtable
(FRTR) are working jointly to publish case studies of full-scale remediation and
demonstration projects. In March, 1995, the FRTR published a four-volume series of
case study reports. At this time, the FRTR is publishing two additional volumes of case
study reports, providing case studies of site cleanup projects using bioremediation,
vitrification, soil vapor extraction, and other in situ technologies.
The case studies were developed by the U.S. Environmental Protection
Agency (EPA), the U.S. Department of Defense (DoD), and the U.S. Department of
Energy (DOE). The case studies were prepared based on recommended terminology
and procedures from the Guide to Documenting Cost and Performance for Remediation
Projects (EPA-542-B-95-002; March 1995). They present available cost and performance
information for full-scale remediation efforts and several large-scale demonstration
projects. The case studies are meant to serve as primary reference sources, and contain
information on site background and setting, contaminants and media treated, technology,
cost and performance, and points of contact for the technology application. The studies
contain varying levels of detail, reflecting the differences in the availability of data and
information. Because full-scale cleanup efforts are not conducted primarily for the
purpose of technology evaluation, data collection on technology cost and performance is
often limited.
This volume contains reports on nine projects. Three of the projects were
full-scale projects using SVE - two in situ and one ex situ. Two of the projects were
large-scale demonstrations of technologies used to enhance the effectiveness of SVE, and
another project demonstrated an innovative technology for treating off-gasses from an
SVE system. Three of the projects concerned other in situ technologies - a frozen soil
barrier containment technology, an innovative approach to drilling monitoring or
remediation wells, and a technology for performing hydraulic and pneumatic fracturing
of subsurfaces.
Table 1 provides a summary including information on technology used,
contaminants and media treated, and project duration for the nine soil vapor extraction
and other in situ technology projects in this volume. This table also notes highlights of
the technology applications. Table 2 summarizes cost data, including information on
quantity of media treated and contaminant removed. In addition, Table 2 shows a
calculated unit cost for some projects, and identifies key factors potentially affecting
project cost. While a summary of project costs is useful, it is difficult to compare costs
for different projects because of site-specific factors and differences in level of detail.
Cost data are shown on Table 2 as reported in the case studies, and have not been
adjusted for inflation to a common year basis. The dollar values shown in Table 2
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should be assumed to be dollars for the time period that the project was in progress
(shown on Table 1 as project duration).
The project costs shown in the second column of the table were compiled,
where possible, according to an interagency Work Breakdown Structure (WBS).1 The
WBS specifies costs as 1) before-treatment costs, 2) after-treatment costs, or 3) treatment
costs. (Table 2 provides some additional information on activities falling under each
category.) In many cases, however, the available information was not sufficiently
detailed to be broken down in this way.
The column showing the calculated treatment cost provides a dollar value
per unit of soil or groundwater treated and, where available, per pound of contaminant
removed. Note that when calculated costs are available on a per cubic yard or per ton
basis, costs cannot be converted back-and-forth due to limited availability of soil bulk
density data, and, therefore, comparisons using the information in this column may be
complicated.
Key factors that potentially affect project costs include economies of scale,
concentration levels in contaminated media, required cleanup levels, completion
schedules, and hydrogeological conditions. It is important to note that several projects in
the case study series represent early applications, and the costs of these technologies are
likely to decrease in the future as firms gain experience with design and operation.
'Additional information on the contents of the WBS and on whom to contact for WBS and related
information is presented in the Guide to Documenting Cost and Performance for Remediation Projects.
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Table 1. Summary of Remediation Case Studies: Soil Vapor Extraction and Other In Situ Technologies
Site Name, State (Technology)
Contaminants Treated :
»m
and/or
TPH
Chlorinated
Aliphatics
Sfoa-
cHorinated
Aliphatics
Historical Actirity
(Principal Contaminants)
Media (Quantity)
Project
Duration
Highlights
Soil Vapor Extraction (SVE)
Basket Creek Surface Impoundment Site, GA
(SVE)
Sacramento Army Depot Superfund Site, Burn
Pits Operable Unit, CA (SVE)
Sand Creek Industrial Superfund Site, Operable
Unit No. 1, CO (SVE)
•
•
•
. •
•
•
Illegal disposal of liquid
refinery and other hazardous
wastes (Toluene, MffiK)
Army support - Burn Pits
(TCE, PCE, DCE)
Pesticide manufacturing,
petroleum refinery (PCE,
TCE)
Soil (1,600 yd3)
Soil (247,900 yd3)
Soil (31,440-
52,920 yd3)
9/92 - 4/93
5/94 - 9/95
9/93 - 4/94
SVE was performed after low-permeability soil
was excavated (ex situ SVE).
SVE system combining injection and extraction
wells in a complex subsurface.
SVE system combining injection and extraction
wells.
Enhancements/Additions
U.S. Department of Energy, Portsmouth
Gaseous Diffusion Plant, OH (In Situ
Enhanced Soil Mixing)
U.S. Department of Energy Savannah River
Site, SC (Flameless Thermal Oxidation)
U.S. Department of Energy, Savannah River
Site, SC, and Hanford Site, WA (Six Phase Soil
Heating)
Other In Situ Technologies
U.S. Department of Energy, Portsmouth
Gaseous Diffusion Plant, OH, and Other Sites
(Hydraulic and Pneumatic Fracturing)
U.S. Department of Energy, SEG Facilities, TN
(Frozen Soil Barrier Technology)
U.S. Department of Energy, Multiple Sites
(ResonantSonic Drilling)
•
•
•
Waste Treatment Plant
(TCE, TCA, DCE)
Nuclear material production
and research (TCE, PCE,
TCA)
Nuclear material production
and research (TCE, PCE)
Soil (not
provided)
Off-Gases (not
provided)
Soil and Sediment
(not provided)
6/92
4/95 - 5/95
10/93 - 1/94
Field demonstration of four technologies used to
remediate fine-grained soils, including enhancing
SVE performance.
Field demonstration of an alternative technology
for treatment of extracted vapors during an SVE
application.
Field demonstration of technology used to
enhance removal of contaminants from clayey soil
during an SVE application.
•
Tinker AFB - Underground
Storage Tank
Others - not provided
(VOCs, DNAPLs, product)
Not applicable (not a
contaminated site)
Not applicable (not a
contaminated site)
Soil and
Groundwater (not
provided)
Soil (35,694 ft3)
Soil and Sediment
(not provided)
7-91 - 8/96
(multiple
demonstra-
tions during
this period)
5/94 - 10/94
1992 - 1994
Field demonstrations of technology used to
increase hydraulic conductivity, contaminant mass
recovery, and radius of influence (for example, in
a SVE application).
Field demonstration of technology used to control
waste migration in soils.
Multiple field demonstrations of alternative
drilling technology that in some applications may
be less costly and produce less drilling waste than
cable tool or mud rotary technologies.
Key:
MIBK - Methyl Isobutyi Ketone
TCE - Trichloroethene
PCE - Tetrachloroethene
DCE - 1,2-Dichloroethene
TCA - 1,1,1-Trichloroethane
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Table 2. Remediation Case Studies - Summary of Cost Data
Site Name, State (Technology)
Project Cost ($)*
Quantity Treated
Quantity of
Contaminant
Removed
Calculated Cost for
Treatment**
Key Factors Potentially Affecting
Project/TecbnoJogy Cosfs***
Soil Vapor Extraction
Basket Creek Surface
Impoundment Site, GA (SVE)
Sacramento Army Depot
Superfiind Site, Burn Pits
Operable Unit, CA (SVE)
Sand Creek Industrial Superfiind
Site, Operable Unit No. 1, CO
(SVE)
T - 660,000
B - 1,300,000
A -220,000
T - 670,500
B - 195,000
T - 2,058,564
B - 81,231
1,600yd5
247,900yd3
31,440-52,920 yd3
72,084 Ibs
138 Ibs
176,500 Ibs
5413/yd3
($275/ton)
$9.20/Ib VOC
$2.70/yd3
$4,858/lbVOC
$39-65^0*
$11.70/lbVOC
This project addressed treatment of a
relatively small quantity of highly-
contaminated soil.
This project addressed treatment of a
relatively large quantity of less-
contaminated soil.
The calculated unit costs varied
depending on how soil quantify treated
was estimated (larger estimates of soil
quantity treated lead to lower unit
costs).
Enhancements/Additions
U.S. Department of Energy,
Portsmouth Gaseous Diffusion
Plant, OH (In Situ Enhanced
Soil Mixing)
U.S. Department of Energy
Savannah River Site, SC
(Flameless Thermal Oxidation)
U.S. Department of Energy,
Savannah River Site, SC, and
Hanford Site, WA (Six Phase
Soil Heating)
C - 1,956,000
O - 20,000/day
C - 50,000
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
$150-200/yd3 (projected)
$0.72/lb VOC destroyed
(projected)
SSe/yd3 (projected)
Demonstration project: Technology
costs vary based on required materials
and equipment.
Demonstration project: Heating content
of off-gas and economies-of-scale are
key factors affecting cost.
Demonstration project: Diameter and
depth of plume, energy demand, and
type of contaminants are key factors
affecting cost.
Project Cost* Calculated Cost for Treatment**
T = Costs for treatment activities, including preprocessing, capital equipment, operation, and maintenance "Calculated based on costs for treatment activities (T): excludes costs for before- (B) and
B = Costs for before-treatment activities, including site preparation, excavation, and sampling and analysis after- (A)treatment activities. Calculated costs shown as "Not Calculated" if an estimate of
A = Costs for after-treatment activities, including disposal of residuals and site restoration treatment costs unavailable.
C = Capital costs
O = Annual operating costs
'For full-scale remediation projects, this identifies factors affecting actual project costs. For demonstration-scale projects, this identifies generic factors which would affect project costs for a future
application using this technology.
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Table 2. Remediation Case Studies - Summary of Cost Data (Continued)
Site Name, State (JPedtoology)
Project Cost ($)* :
Quantify Treated
Quantity of
Contaminant
Removed
Calculated Cost for
TreatoeBt**
JKey Factors Potentially Affecting
i Sr<>ject/T«!jjnology <3esfe***
Other In Situ Technologies
U.S. Department of Energy,
Portsmouth Gaseous Diffusion
Plant, OH, and Other Sites
(Hydraulic and Pneumatic
Fracturing)
U.S. Department of Energy,
SEG Facilities, TN (Frozen Soil
Barrier Technology)
U.S. Department of Energy,
Multiple Sites (ResonantSonic
Drilling)
Not provided
C - 481,427
Not provided
Not provided
35,694 ft?
Not provided
Not provided
Not provided
Not provided
$8-17/yd3 soil treated
$140/lb TCE removed
14-14/ft3 ice formed
(projected)
$208-270/ft well drilled
(projected)
Demonstration project: Labor, capital
equipment, site preparation, and
residuals disposed are key factors
affecting cost.
Demonstration project: Quantity of
refrigeration and barrier thickness
needed are key factors affecting cost.
Demonstration project: Drilling
difficulty and type of site (e.g.,
uncontaminated, hazardous waste,
mixed waste) are key factors affecting
cost.
Calculated Cost for Treatment**
Project Cost*
T = Costs for treatment activities, including preprocessing, capital equipment, operation, and maintenance "Calculated based on costs for treatment activities (T): excludes costs for before- (B) and
B = Costs for before-treatment activities, including site preparation, excavation, and sampling and analysis after- (A)treatment activities. Calculated costs shown as "Not Calculated" if an estimate of
A = Costs for after-treatment activities, including disposal of residuals and site restoration
C = Capital costs
O = Annual operating costs
treatment costs unavailable.
•For full-scale remediation projects, this identifies factors affecting actual project costs. For demonstration-scale projects, this identifies generic factors which would affect project costs for a future
application using this technology.
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SOIL VAPOR EXTRACTION
CASE STUDIES
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Soil Vapor Extraction at the Basket Creek
Surface Impoundment Site, Douglasville, Georgia
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Case Study Abstract
Soil Vapor Extraction at the Basket Creek
Surface Impoundment Site, Douglasville, Georgia
Site Name:
Basket Creek Surface Impoundment
Site
Location:
Douglasville, Georgia
Contaminants:
Organic Compounds (Volatiles -
Halogenated: trichloroethene (TCE); and
Volatiles - Nonhalogenated: toluene, methyl
isobutyl ketone (MIBK), and methyl ethyl
ketone (MEK)) and Inorganic Compounds
(Heavy Metals: lead and mercury)
- Toluene: BDL-220,000 mg/kg
- MIBK: BDL-66,000 mg/kg
- MEK: BDL-23,000 mg/kg
Period of Operation:
November 1992 to April 1993
Cleanup Type:
Full-scale cleanup
Vendor:
Mark Rigatti
OHM Remediation Services Corp.
5335 Triangle Parkway, Suite 450
Norcross, GA 30092
(770) 453-7630
SIC Code:
4953 W (Refuse Systems - waste
processing facility, miscellaneous)
Technology:
Soil Vapor Extraction (ex situ)
- In situ SVE was not used because of low
soil permeability
- Soil was excavated on a grid basis
- 48 grids were excavated, each 10x10 ft
square
- Treatment was conducted in metal building
60 ft wide by 120 ft long by 26 ft tall
- System included shaker (power) screen, 17
horizontal vapor extraction wells, 3 vacuum
pumps, a baghouse, and a thermal oxidizer
Cleanup Authority:
CERCLA
- Action Memorandum Date
4/11/91
- Fund Lead
Point of Contact:
R. Donald Rigger
USEPA Region 4
345 Courtland Street, N.E.
Atlanta, GA 30365
(404) 347-3931
Waste Source:
Surface Impoundment/Lagoon
Purpose/Significance of
Application:
Ex situ SVE application on low-
permeability soil contaminated with
organic and inorganic constituents.
Type/Quantity of Media Treated:
Soil
- 1,600 cubic yards (2,400 tons)
- Particle size distribution: clay - 16.4%; silt - 34.4%; sand - 40.8%; and gravel
8.4%
- Air permeability: 1.5xlO"7 cm/sec
Regulatory Requirements/Cleanup Goals:
- Soil treatment targets identified for 4 VOCs, lead, mercury, and total HOCs
- Targets for VOCs and metals set at TC regulatory levels
Results:
- Soil treatment targets met for all 14 sampling grids after 6 months of treatment
- TCLP results were as follows: TCE - <0.1 mg/L; PCE - < 0. 3 mg/L; benzene - <0.03 mg/L; MEK - < 2.0 mg/L;
lead < 2.0 rag/L; and mercury - all ND
- 72,000 Ibs of total VOCs recovered in this application
10
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Case Study Abstract
Soil Vapor Extraction at the Basket Creek
Surface Impoundment Site, Douglasville, Georgia (Continued)
Cost Factors:
- Actual costs of $2,200,000 were expended, including $1,300,000 for before-treatment activities, $660,000 for activities
directly attributed to treatment, and $220,000 for after-treatment activities
- The unit cost for activities directly attributed to treatment was $413/yd3 of soil treated ($275/ton), and $9.20/lb of
VOC removed
Description:
Basket Creek was used in the 1960s for illegal disposal of liquid refinery and other hazardous wastes. In 1991, soil at
the site was identified as a RCRA hazardous waste exhibiting the Toxicity Characteristic (TC) for lead, MEK, and TCE.
Soil samples collected in March 1990, May 1991, and January 1992 showed the following concentrations in a total waste
analysis: TCE - below detection limit (BDL) to 8,600 mg/kg; PCE - BDL to 2,700 mg/kg; toluene - BDL to 220,000
mg/kg; xylenes - BDL to 7,300 mg/kg; MEK - BDL to 23,000 mg/kg; and MIBK - BDL to 66,000 mg/kg.
An action memorandum for Basket Creek was signed on April 11, 1991 and specified soil treatment targets for TCE,
PCE, benzene, MEK, lead, mercury, and total halogenated organic compounds (HOCs). An ex situ SVE system was
used at Basket Creek, consisting of a 7,200 ft2 containment building, a shaker (power) screen, 17 vapor extraction wells,
vacuum pumps, a baghouse, an induced draft blower, and a thermal oxidizer. Excavation, screening, and vapor
extraction all took place inside the containment building. The system was run from November 1992 to February 1993,
and again from March to April 1993, for a total of 6 months of operation.
Analytical data indicated that the soil treatment targets were met for all contaminants after the six. month treatment
period. Total VOCs in the treated soil ranged from 0.142 to 1570.7 mg/kg, and approximately 72,000 Ibs of total VOCs
were recovered from the soil. Toluene was the largest quantity VOC recovered, accounting for approximately 80% of
the total VOCs recovered, and MIBK was the second largest quantity, accounting for 11%. Ex situ SVE was selected
for this application after in situ SVE was ruled out because of the low permeability of the contaminated soil. Excavation
of soil was performed within an enclosure to control emissions. Because of space constraints, this resulted in the
excavation taking a much longer time (3 months) than would have been required were the excavation to have been done
outside (a few days).
11
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Basket Creek Surface Impoundment Site, Page i of 24 •
| COST AND PERFORMANCE REPORT |
|^B EXECUTIVE SUMMARY
This report presents cost and performance data for a soil vapor extraction (SVE) system at the Basket
Creek Surface Impoundment site in Douglasville Georgia. The SVE system was used at Basket Creek to
treat soil contaminated with halogenated volatile organic compounds (VOCs), including trichloroethene
(TCE) and tetrachloroethene (PCE), and nonhalogenated VOCs including toluene, xylenes, methyl
isobutyl ketone (MIBK), and methyl ethyl ketone (MEK).
Basket Creek was used in the 1960s for illegal disposal of liquid refinery and other hazardous wastes;
however information on the quantity and specific types of waste disposed in the impoundment is not
available. In 1991, soil at the site was identified as a RCRA hazardous waste exhibiting the Toxicity
Characteristic (TC) for lead, MEK, and TCE. Soil samples collected in March 1990, May 1991, and
January 1992 showed the following concentrations in a total waste analysis: TCE - below detection limit
(BDL) to 8,600 mg/kg; PCE - BDL to 2,700 mg/kg; toluene - BDL to 220,000 mg/kg; xylenes - BDL to
7,300 mg/kg; MEK - BDL to 23,000 mg/kg; and MIBK - BDL to 66,000 mg/kg.
An action memorandum for Basket Creek was signed on April 11, 1991 and specified soil treatment
targets for TCE, PCE, benzene, MEK, lead, mercury, and total halogenated organic compounds (HOCs).
The cleanup levels ranged from 0.2 to 200 mg/L (measured using a TCLP) for all contaminants except
total HOCs. The target for total HOCs was 1,000 mg/kg, based on the land disposal restrictions for
California List wastes. In addition, EPA and the State of Georgia required that the thermal oxidizer
maintain a minimum destruction efficiency of 95%.
The SVE system used at Basket Creek was an ex situ application, consisting of a 7,200 ft2 containment
building, a shaker (power) screen, 17 vapor extraction wells, vacuum pumps, a baghouse, an induced
draft blower, and a thermal oxidizer. Excavation, screening, and vapor extraction all took place inside
the containment building. EPA had originally considered using in situ SVE, but ruled it out because of
the relatively low permeability of soil (excavation and power screening helped to increase the
permeability of the soils in the ex situ process). The system was run from November 1992 to February
1993, and again from March to April 1993, for atotal of 6 months of operation.
Analytical data indicated that the soil treatment targets were met for all contaminants after the six month
treatment period. Total VOCs in the treated soil ranged from 0.142 to 1570.7 mg/kg, and approximately
72,000 Ibs of total VOCs were recovered from the soil. Toluene was the largest quantity VOC
recovered, accounting for approximately 80% of the total VOCs recovered, and MIBK was the second
largest quantity, accounting for 11%. The thermal oxidizer achieved a destruction efficiency of at least
95% during system operation, and for three months of at least 98%.
Approximately $2.2 million were expended in this application, including $1.3 million for before-
treatment activities, $660,000 for activities directly attributed to treatment, and $220,000 for after-
treatment activities, including off-site disposal of treated soil. Approximately $650,000 of the before-
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
12
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| EXECUTIVE SUMMARY (CONT.)
Basket Creek Surface Impoundment Site, Page i of 24 •
treatment costs were for the building (enclosure), air handling system, and treatment of building vapors
in the incinerator.
The $660,000 in costs directly attributed to treatment activities corresponds to $413 per cubic yard
treated (1,600 cubic yards), $275 per ton of soil treated (2,400 tons), and $9.20 per pound of VOC
removed (approximately 72,000 pounds VOC removed). These unit costs reflect treatment of a
relatively small quantity of soil that contained a relatively high concentration of contaminants.
According to the OSC, excavation within an enclosure takes longer than outside due to the space
constraints. Normally, the excavation at Basket Creek would have been completed in a few days, instead
of the three months actually taken.
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• Basket Creek Surface Impoundment Site, Page 1 of 24
[ SITE INFORMATION
Identifying Information:
Basket Creek Surface Impoundment site
Douglasville, Georgia
CERCLIS # GAD980843833
Action Memorandum Date: 4/11/91
Treatment Application:
Type of Action: Removal
Treatahility Study Associated with Application? Yes
(see discussion under Remedy Selection)
EPA SITE Program Test Associated with Application? No
Period of Operation: 11/92 - 4/93
Quantity of Material Treated During Application: Approximately 1,600 cubic yards (2,400
tons) of soil [2]
Background
Historical Activity that Contributed to Contamination at the Site: Waste Disposal
Corresponding SIC Code: 4953 W (Refuse Systems - waste processing facility, miscellaneous)
Waste Management Practice that Contributed to Contamination: surface
impoundment/lagoon
Site History: The Basket Creek Surface Impoundment site (Basket Creek) is located in
Douglasville, Georgia, as shown in Figure 1. The site was contaminated during the 1960s when
it was used for the illegal disposal of hazardous wastes. At that time, an intermittent stream bed
was dammed with soil to form a small impoundment. The impoundment area measured 35 feet
north to south and 50 feet east to west, and ranged in depth from 6 to 12 feet. [1,2]
Liquid refinery and other hazardous wastes were reportedly disposed in the impoundment over a
number of years. However, information on the quantity and specific types of waste disposed was
not available. The impoundment was accidentally ignited in July of 1970 and burned for several
days. Subsequent to the fire, local officials required the landowner to discontinue waste disposal
and cover the impoundment with soil. [1,2]
In November 1989, EPA performed a Hazard Ranking System evaluation for Basket Creek. The
evaluation was limited to a review of existing file material, completion of a target survey, and a
site walk-through. Based on that evaluation, the site did not qualify for the National Priorities
List(NPL). [3]
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• Basket Creek Surface Impoundment Site, Page 2 of 24
I SITE INFORMATION (CONT.)
Background (cont.)
u
Regulatory Context: EPA signed an
Action Memorandum for Basket Creek
on April 11, 1991. Initial activities
included sampling to characterize the
nature and extent of contamination at
the site. The soil was found to be a
RCRA hazardous waste by exhibiting
the Toxicity Characteristic (TC) for
lead (Waste Code D008), methyl ethyl
ketone (Waste Code D035), and
trichloroethene (Waste Code D039).
Additionally, the soil was found to be a
California List Waste under the RCRA
Land Disposal Restrictions program
because total halogenated organic
compounds were greater than 1,000
parts per million (ppm) and, therefore,
waste from the site was prohibited from
land disposal. As described under the
Contamination Characterization section
of this report, elevated levels of
mercury were also found in the soil;
however, the soil was not identified as
exhibiting the TC for mercury. [3]
Basket Creek Surface
Impoundment Site
Douglasville, Georgia
Figure 1. Site Location
The action memorandum identified treatment targets for soil, including TC regulatory levels for
selected volatile organic compounds (VOCs) and metals, and the California List regulatory level
of 1,000 ppm for total HOCs. [3]
Remedy Selection: EPA evaluated several potential remedies for this site. The first remedy
evaluated, off-site incineration, was not selected because of cost. Bids for off-site incineration of
soil from Basket Creek ranged from $2,500 to $2,800 per ton. [3] According to the OSC, the
incineration bids were high because of the elevated mercury levels. [13]
Two on-site treatment technologies, in situ soil vapor extraction and low temperature thermal
desorption, were also considered, and treatability studies were conducted for each technology. In
situ soil vapor extraction was ruled out because of the low permeability of the contaminated soil.
During the low temperature thermal desorption treatability study, the soil sample ignited. This
indicated that the soil was too highly contaminated with VOCs to treat safely with low
temperature thermal desorption and EPA did not select this technology. [1]
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-Basket Creek Surface Impoundment Site, Page 3 of 24
j SITE INFORMATION (CONT.)
Background (cont.)
The remedy selected by EPA for this site was ex situ soil vapor extraction (SVE). The remedy
included excavating the soil from the impoundment, processing the soil through a power screen,
stockpiling the soil on site, and treating the stockpiled soil with an ex situ SVE system.
According to the OSC, the SVE system was installed primarily to control VOC emissions from
the stockpile. [3,13] According to the vendor, bench-scale testing was performed for this
application; however, no details of the study or results were provided. [14]
Calculations were made to estimate the quantity of VOCs that would be released to the
atmosphere from the excavation, screening, and stockpiling operations. The maximum quantity
of VOCs released from the operations as fugitive emissions was estimated at 1,800 pounds per
day. Depending on weather conditions, these emissions posed potential health risks for local
residents and a threat to general air quality. EPA decided to include the following engineering
controls to minimize fugitive emissions [3]:
* Construction of an enclosure large enough to cover the impoundment area and stockpile
area;
• Development of an ah- handling system capable of exhausting a sufficient quantity of
contaminated air to maintain a safe working environment in the building; and
• Installation of a thermal oxidizer (fume incinerator) to thermally destroy the VOCs in the
air stream exhausted from the building.
Site Logistics/Contacts
Site Management: Fund-Lead
Oversight: EPA
On-Scene Coordinator:
R. Donald Rigger
U.S. EPA Region 4
345 Courtland Street, N.E.
Atlanta, Georgia 30365
(404)347-3931
Treatment Vendor:
Mark Rigatti
OHM Remediation Services Corp.
5335 Triangle Parkway, Suite 450
Norcross, GA 30092
(770) 453-7630
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-Basket Creek Surface Impoundment Site, Page 4 of 24
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the Treatment System: soil (ex situ)
Contaminant Characterization
Primary Contaminant Groups: Organic Compounds (Volatiles - Halogenated:
trichloroethene; and Volatiles - Nonhalogenated: toluene, methyl isobutyl ketone, and methyl
ethyl ketone) and Inorganic Compounds (Heavy Metals: lead and mercury)
Soil samples were collected by EPA in the surface impoundment in March 1990, May 1991, and
January 1992, and analyzed for organics and metals. The results of these investigations for
reported constituents are shown in Table 1.
The composite sample collected in May 1991 consisted of nine grab samples from various
depths in the former impoundment. As shown in Table 1, the May 1991 sample was
characterized by total waste analysis and Toxicity Characteristic Leaching Procedure (TCLP).
The sample collected in January 1992 was collected as a "worst-case" sample (i.e., the most
highly contaminated part of the site) for treatability testing. [2,4,9, 13]
Table 1. Results of Soil Sampling for Reported Constituents in Surface Impoundment
s ' '?
a /
s'S
Constituent
j
< \
Samples Collected
March 1990 -Total
Waste Analysis [9]
-'(rag/kg) ^
.Samples Collected May 1991 [4]
Composite
Sample Total
Waste Analysis
"(mg/kg)
Composite
Sample TCLP
<«ng/L)
/ '
Sample Collected
January 15*2 -
Total Waste
Analysis* [2]
- (mg/fcg)
Volatile Organics
Trichloroethene
Tetrachloroethene
Toluene
Ethylbenzene
Xylenes (total)
2-Butanone (Methyl Ethyl Ketone)
4-Methyl-2-Pentanone
(Methyl Isobutyl Ketone)
BDL (90)
BDL (120) - 720
9,300-11,000
BDL (220)
1,300 - 1,500
890
1,400
BDL (90.0)
230
11,000
BDL (240)
1,280
BDL
4,700
BDL (11.0)
BDL
BDL
BDL
BDL
280.0
BDL
8,600
2,700
220,000
1,600
7,300
23,000
66,000
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-Basket Creek Surface Impoundment Site, Page 5 of 24
| MATRIX DESCRIPTION (CONT.) |
Contaminant Characterization (cont.)
Table 1. (Continued)
Constituent
Samples Collected
March 1990 -Total
Waste Analysis [9]
(mg/kg)
Samples Collected May 1991 [4]
Composite
Sample Total
Waste Analysis
(mg/kg)
Composite
Sample TCLP
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-Basket Creek Surface Impoundment Site, Page 6 of 24
TREATMENT SYSTEM DESCRIPTION
Primary Treatment Technology Type: Soil Vapor Extraction (ex situ)
Supplemental Treatment Technology Type;
Pretreatment: power screening,
Post-treatment (air): baghouse, thermal oxidizer
Soil Vapor Extraction System Description and Operation
System Design [1, 2, 11]
The SVE system used at Basket Creek included the following equipment: a metal building
measuring 60 feet wide by 120 feet long by 26 feet tall; a shaker (power) screen; 17 horizontal
vapor extraction wells; and three vacuum pumps for the vapor extraction system (with filters and
silencers). In addition, the system included a baghouse (dust collector), an induced draft blower
for exhausting the building air, and a thermal oxidizer to treat the contaminated air and vapor
streams.
Figure 2 shows the layout for the treatment system used at Basket Creek. As shown in Figure 2,
the vapors extracted from the soil stockpile were combined with the vapors extracted from the
building air prior to treatment in the thermal oxidizer.
The building was designed to totally enclose the impoundment and also have sufficient room for
treatment of the stockpiled soil. Inside the building, soil was excavated, processed through a
power screen, and stockpiled. The soil was excavated using a track mounted excavator and
placed directly into a power screen. The power screen was used to shred soil clumps and break
up the soil to increase the soil permeability. The power screened soil was transported to the
stockpile area using a 25-foot long covered stacking conveyor. According to the OSC, analytical
data for vapors extracted from the building and soil stockpile showed that 20% to 25% of the
VOCs recovered during this application came from the excavation and screening operations.
The soil vapor extraction system consisted of seventeen 4-inch diameter slotted well screen
strings lying horizontally through the soil stockpile. The well screens were placed in three rows,
six near ground level, five at 4 feet above ground level, and six more at 7 feet above ground
level. Chemical resistant sleeves were placed over the well screen sections to prevent soil from
clogging the slots. As the stockpile was built, additional well screen sections were screwed onto
the previous section and covered with excavated soil. The vacuum for each well screen row was
supplied by a 1,240-cubic feet per minute (cfm) vacuum pump. Each vacuum pump was
equipped with a filter canister and a silencer to reduce the high pitched noise of the pump.
Vapors were drawn out of the stockpile and routed to the thermal oxidizer through PVC piping.
In addition, vapors were collected using a movable fume hood at two locations inside the
building: at the excavation; and at the power screen. The vacuum for the excavation and power
screen was supplied by an 8,000-cfm, 50 horse power (hp) induced draft blower located outside
the operations building. A baghouse was used to remove all particulates from the air stream.
The baghouse consisted of a metal structure housing 96 filter bags designed to remove particles
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Basket Creek Surface Impoundment Site, Page 7 of 24
| TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
V*aumPump
FSlen
Sol SloctplWHottonul V.por
Extraction Well! (17 total)
Stakor
ScrMn
Operations
Building
Figure 2. Treatment System Layout [2]
down to 0.5 microns. The system used 24-inch flexible duct work to route the vapors from the
interior of the building to the exterior. Galvanized steel ducts were used to route the air through
the baghouse and into the thermal oxidizer.
The thermal oxidizer was a three chamber, propane fired unit designed to treat 10,000 cfm of
vapors with greater than 99% destruction and removal efficiency. Five 1,000-gallon propane
tanks were staged on site to supply fuel for the unit.
System Operation [1,2]
In October 1992, a trial burn of the thermal oxidizer was performed. Soil from the impoundment
was exposed with a trackhoe and the soil was stirred to liberate VOCs. The contaminated vapor
was routed through the duct work and into the thermal oxidizer which was operated at
approximately 1,600°F. The residence time for the thermal oxidizer was not provided for this
application. Mass emission rates were calculated for VOCs, semivolatile organic compounds,
dioxins, and fiirans, and were reported to the Agency for Toxic Substances and Disease Registry
(ATSDR - an agency of the U.S. Public Health Service). ATSDR determined that the predicted
emissions from the thermal oxidizer would not pose a threat to public health. In addition,
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Basket Creek Surface Impoundment Site, Page 8 of 24
| TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
ATSDR recommended that stack emissions be continuously monitored. In response to this
recommendation, continuous emission monitors (total hydrocarbon analyzers) were installed at
the inlet and outlet of the thermal oxidizer.
Full-scale operations began in November 1992. The area of contamination (60 feet wide by 80
feet long and varying in depth to up to 14 feet) was divided into forty-eight 10-foot by 10-foot
grids. Excavation was performed within individual grids to limit the surface area of exposed
soil. Rocks and debris larger than 2 inches were rejected by the power screen, and placed in roll-
off boxes. Excavation was halted when solid homogeneous rock was encountered.
The vapor extraction system was operated continuously; VOC recovery associated with the
excavation and screening operations was operated an average of 25 to 30 hours per week, during
excavation and screening operations. All of the recovered VOCs were routed to the thermal
oxidizer for treatment.
System Shutdown T21
In February 1993, excavation and backfilling of the 48 grid sections was completed. The vapor
extraction system was operated for three weeks after excavation to complete treatment of the
soil.
The stockpiled soil was then divided into 20-foot grid sections and sampled. The results
indicated that the VOC levels in the majority of the grid sections had met the target levels (see
discussion under cleanup goals/standards). However, the results also showed that contamination
above the target levels still remained in several grid sections. These grids were re-excavated and
treated in the stockpile SVE system in March and April 1993. Analytical results showed that in
April 1993 the soil met the target levels (see results under Treatment Performance Data) and the
soil was transported to the BFI industrial waste landfill in Buford, Georgia. A total of 2,366.72
tons of soil was transported off site for disposal.
Approximately 100 tons of rocks and debris from the power screening operation were disposed
of at the BFI facility in Buford, Georgia. Eighteen (18) cubic yards of excavated metal and
crushed drums were also transported off site in April 1993 to the Laidlaw Hazardous Waste
Landfill in Pinewood, South Carolina, where they were disposed by direct burial.
Approximately 4,250 gallons of decontamination water (from health and safety activities - see
discussion below) were transported off site in May 1993 by International Petroleum Corporation
for treatment at their facility in Fairburn, Georgia.
In addition, nine drums containing paint waste were transported in May 1993 to the Thermal-
Chem facility in Rock Hill, South Carolina, for incineration.
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—i— —. Basket Creek Surface Impoundment Site, Page 9 of 24
[ TREATMENT SYSTEM DESCRIPTION (CONT.) j^^^BI^^MHHH
Soil Vapor Extraction System Description and Operation (cont.)
Site Restoration F21
Site restoration activities included dismantling and removal of the operations building and other
process equipment. The site was then regraded using on-site soil, and grass seed and straw were
distributed throughout the areas affected by the removal. In August 1993, the application of seed
was completed.
Health and Safety [1,2]
One of the main concerns regarding the safety of the personnel inside the operations building
was the buildup of VOCs from the soil excavation and screening and the possibility of a fire or
an explosion. To address these concerns, a site safety officer was present inside the enclosure at
all times when excavation was taking place. Workers wore Level B personal protective
equipment (PPE) consisting of supplied air breathing apparatus, fire resistant coveralls,
disposable outer suits and boots, and hard hats. Workers decontaminated reusable PPE on site.
The safety officer was responsible for monitoring air quality inside the enclosure. A
Combustible Gas Indicator was used to monitor the concentration of combustible gas in the
airspace. A limit of 10% of the Lower Explosive Limit (LEL) was set as an automatic cease-
work condition. If 10% of the LEL was reached, all work stopped and the workers evacuated the
building until the levels had dropped back into the safe range. A Photo-Ionization Detector
(PID) was also used to monitor airborne contaminants as total hydrocarbons. A limit of 500 ppm
total hydrocarbons in air was also set as a cease-work condition.
Another safety concern was the potential to develop an explosive atmosphere in the air handling
duct work, both inside and outside the enclosure. A limit of 20% of the LEL was set for all
components of the air handling system, including the vapor extraction piping, the flexible duct
work, and the steel duct work. Eight LEL detectors were placed throughout the air handling
system, and connected to a central control panel. Whenever any one of the eight detectors
registered 15% of the LEL, an audible alarm would sound, and personnel inside the building
would discontinue excavation. A reading of 20% of the LEL caused automatic interlocks to
activate which shut down the blower.
According to the OSC, the 15% LEL level in the duct work was exceeded several times per day
during excavation of highly contaminated areas. In addition, there were several times during the
project when the 20% level was exceeded. [13]
In addition, air monitoring was conducted around the perimeter of the operations building and
using off-site high volume air sampling equipment.
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"Basket Creek Surface Impoundment Site, Page 10 of 24
j TREATMENT SYSTEM DESCRIPTION (CONT.)
Operating Parameters Affecting Treatment Cost or Performance
The major operating parameters affecting cost or performance for this technology and the values
measured for each are shown in Table 3.
TableS. Operating Parameters [13]
Parameter ,
Air Flow Rate
Operating Pressure/Vacuum
Value
3,000 cfm
4 inches mercury
Measurement Method
N/A
N/A
N/A - Measurement method not reported for this parameter because resulting value not expected to vary
among measurement methods.
Timeline
A timeline for this application is shown in Table 4.
Table 4. Timeline [1,2]
Start Date
April 1991
April 1992
October 1992
November 1992
March 1993
May 1993
.End Bate *
May 1992
April 1993
May 1993
August 1993
"„ ' • Activity^ X J.\ :;.... .;.';... ••".; '".-..- • ;
Action memorandum signed
Operations building constructed
Trial Burn performed
Full-scale operations conducted
Treated soil disposed off site
Site restoration activities completed
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• Basket Creek Surface Impoundment Site, Page 11 of 24
TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards
The action memorandum identified treatment targets for stockpiled soil, including TC regulatory
levels for selected volatile organic compounds (VOCs) and metals, and the California List
regulatory level of 1,000 ppm for total HOCs, as shown in Table 5. [3]
Table 5. Stockpile Soil Treatment Targets [3]
Constituent/Parameter
Trichloroethene (TCE) - TCLP
Tetrachloroethene (PCE) - TCLP
Benzene - TCLP
2-Butanone (MEK) - TCLP
Lead - TCLP
Mercury - TCLP
Total HOCs
Regulatory Level
0.5
0.7
0.5
200
5.0
0.2
1,000
"•fi.. -:v, .#>;:• Units >:S 'W ' ."£f*
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/kg
According to the vendor, EPA and the State of Georgia identified a requirement that the thermal
oxidation unit be at least 95% efficient for VOC destruction, although this is not described in the
action memorandum. [14]
Treatment Performance Data
Treatment performance data for this application include results for treated soil stockpile samples,
power screen reject samples, total VOC and specific VOC recovery data, thermal oxidizer VOC
destruction efficiency data, and air emission results.
Treated Soil Stockpile Samples [21
The treated soil stockpile was sampled using a 20-foot grid system (a layout of the grid system
was not provided). The stockpile was divided into fourteen 20-foot by 20-foot grid sections, and
four sample points were selected from each grid section. The 14 grid sections are labelled:
AB-6,5;
AB-8,7;
AB-10,9;
AB-12,11;
'BC-3,4;
CD-6,5;
CD-8,7;
CD-10,9;
CD-12,11;
DE-3,4;
EF-6,5;
EF-8,7;
EF-10,9; and
EF-12,11.
A hand auger was used to collect aliquots from 2-, 4-, and 8-foot depths at each of the four
sample points within each grid section. All 12 aliquots were composited into one sample. The
stockpile samples were analyzed by TCLP for TCE, PCE, benzene, MEK, lead, and mercury; and
for total VOCs and total HOCs. The results from these analyses for the 14 grid sections are
shown in Table 6.
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• Basket Creek Surface Impoundment Site, Page 12 of 24
Table 6. Treated Soil Stockpile Analytical Data [2]
1 * ' ' "H 1
'"" , _»s, ' ! , ' '< ,
' !'t ^ *• i i*t •* '-si " '!\ 1 fe
- fi Constituent/Parameter
1 \ i i Bs * ., t
Trichloroethene (TCE) - TCLP
Tetrachloroethene (PCE) - TCLP
Benzene - TCLP
2-Butanone (MEK) - TCLP
Lead -TCLP
Mercury - TCLP
Total VOCs
Total HOCs
•* * % ,
'• -^ *
, Regulatory
N ' Levfel ' "
0.5
0.7
0.5
200
5.0
0.2
WA
1,000
^ , t '
<\ 1 ' .
' 1 \ 1 ,
, Units r
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/kg
mg/kg
jt '"K* , }
' ' ( ' rx ',,'," Sample Number , s- , 'x
1 !> t i>
/CB-10,9rT
0.08
0.12
0.001
0.7
0.75
BDL
249.91
12.81
'*
»,Eif-l»,9
0.0015
0.038
0.0007
0.066
0.71
BDL
38.47
1.08
' *i i
EF-12,11,.
BDL
0.019
0.0003
BDL
1.1
BDL
0.347
0.057
C0-12,U
BDL
0.0015
0.0004
BDL
0.6
BDL
0.382
0.237
1 ^ -
EF-6,5 <-,
0.0019
0.044
0.002
0.52
0.28
BDL
70.04
2.98
CDf,5
0.006
0.06
0.0017
0.83
0.27
BDL
166.59
4.07
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• Basket Creek Surface Impoundment Site, Page 13 of 24
Table 6. Treated Soil Stockpile Analytical Data [2] (Continued)
Constituent/Parameter
Trichloroethene (TCE) - TCLP
Tetrachloroethene (PCE) - TCLP
Benzene - TCLP
2-Butanone (MEK) - TCLP
Lead -TCLP
Mercury - TCLP
Total VOCs
Total HOCs
Regulatory
Level
0.5
0.7
0.5
200
5.0
0.2
N/A
1,000
Units
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/kg
mg/kg
Sample Number
BC-3,4
0.0024
0.011
0.0022
1.3
0.79
BDL
131.489
2.709
AB-12,11
BDL
0.0013
0.0013
BDL
0.25
BDL
0.142
0.055
AB-IO,9
BDL
0.17
0.017
MDL
1.8
BDL
1,570.7
7.3
AB-6,5
0.0014
0.011
0.0015
0.42
0.49
BDL
73.77
0.66
AB-8,7
0.014
0.13
0.019
MDL
1.9
BDL
738.5
10.97
CD-8,7
0.045
0.26
0.025
MDL
1.1
BDL
721.42
18
EF-8,7
0.0007
0.046
0.0016
0.48
0.93
BDL
108.671
5.521
to
BDL - Below detection limit.
MDL - Acronym not defined in references.
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• Basket Creek Surface Impoundment Site, Page 14 of 24
| TREATMENT SYSTEM PERFORMANCE (CONT.j
Treatment Performance Data (cont.)
Power Screen Reject Samples F21
The roll-off boxes containing rocks and debris from the power screening operation were also
sampled. Power screen reject sample data were not provided. However, the vendor indicated
that the material met the target levels, and was disposed at the Industrial Waste Landfill in
Buford, Georgia.
Total VOC Recovery Data [21
The quantity of total VOCs recovered from the surface impoundment was calculated by the
treatment vendor using analytical data for the concentrations of VOCs at the inlet to the thermal
oxidizer and the flowrate to the oxidizer. The vendor summed the calculated mass recoveries for
the following VOCs to calculate total VOCs: TCE, PCE, benzene, toluene, ethylbenzene, total
xylenes, MEK, MIBK, and chlorobenzene. The quantities of total VOCs recovered on a weekly
basis from November 1992 to February 1993 are shown in Table 7.
Specific VOC Recovery Data
Table 8 shows a breakdown by VOC and by month for the total VOCs recovered from November
1992 to February 1993.
Table?. Quantity of Total VOCs* Recovered [2]
,' '- • vOpw^gipriM /
11/25-11/30/92
12/1 - 12/7/92
12/8 - 12/14/92
12/15 - 12/22/92
12/28-12/31/92
1/1 - 1/08/93
1/9 - 1/15/93
1/16 - 1/22/93
1/23-1/31/93
2/1 - 2/8/93
2/9 - 2/17/93
2/18-2/25/93
TOTAL
; " Quantity of Total VOCs* Recovered .'
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• Basket Creek Surface Impoundment Site, Page 15 of 24
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 8. Quantity of Specific VOCs Recovered [2, 5]
voc
TCE
PCE
Benzene
Toluene
Ethylbenzene
Total Xylenes
MEK
MffiK
Chlorobenzene
TOTAL*
Quantity Recovered (Ibs)
November
1992
0
0
0
1,543
0
0
0
0
0
1,543
December
1992
182.4
0
0
18,813.0
42.1
402.4
783.3
989.8
0
21,213
January
1993
265.05
179.64
26.72
29,851.67
315.32
1,126.75
1,670.70
4,523.07
19.99
37,979
February
1993
177.88
171.01
0
6,889.01
132.93
571.89
638.31
2,761.27
10.53
11,349
Total*
625.33
350.65
26.72
57,096.28
490.35
2,101.04
3,092.31
8,274.14
30.52
72,083.8
*Totals reflect rounding.
Thermal Oxidizer Destruction Efficiency Data
The destruction efficiency for the thermal oxidizer was measured based on the average
daily inlet and outlet concentrations at the oxidizer. Table 9 shows these results for the
months of November 1992, December 1992, January 1993, and February 1993.
Table 9. Thermal Oxidizer Destruction Efficiency 2, 5]
Operating Period
11/25 to 11/30/92
12/1 to 12/31/92
1/1 to 1/31/93
2/1 to 2/25/93
Average Daily Inlet
Concentrations (ppmv)
10,944
181,032
432,960
149,328
Average Daily Outlet
Concentrations (ppmv)
573.60
3,828
3,878.4
1,125.6
Destruction Efficiency
(%)
95
98
99
99
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
28
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I TREATMENT SYSTEM PERFORMANCE (CONT.}
Treatment Performance Data (cont.)
• Basket Creek Surface Impoundment Site, Page 16 of 24
The OSC speculated that the destruction efficiency performance improved during this
application because the seals in the thermal oxidizer seated better after a 2-month break-in
period. [13]
Air Emission Results
Airborne concentrations of VOCs inside the operations building occasionally approached 500
ppm (the stop work condition) and regularly ranged between 200 and 400 ppm. However,
according to the OSC, no VOCs were detected during hourly air monitoring surveys around the
perimeter of the operations building and no VOCs were detected in off-site high volume air
samples. [1]
Performance Data Assessment
The soil stockpile analytical data shown in Table 6 indicates that the soil treatment targets were
met for all 14 sampling grids after 6 months of treatment. As shown in Table 6, the TCLP
results for the target compounds were as follows: TCE less than 0.1 mg/L, PCE less than 0.3
mg/L, benzene less than 0.03 mg/L, MEK less than 2.0 mg/L, and lead less than 2.0 mg/L. The
TCLP results for mercury were all less than the reported detection limit. Also as shown in Table
6, total HOCs ranged from 0.055 to 20.3 mg/kg, and total VOCs from 0.142 to 1,570.7 mg/kg.
The data in Table 6 also show that there were variations in concentrations among the 14 soil
stockpile grid samples. For example, the total VOC data show a range over four orders of
magnitude in the 14 grid samples (e.g., from 0.142 to 1,570.7 mg/kg).
Although no data are available to characterize the soil in the stockpile prior to treatment, the
surface impoundment data shown in Table 1 present an approximation of the concentrations that
may have been present in the stockpile prior to treatment. As shown in Table 1, total waste
analysis concentrations in the surface impoundment ranged from Below Detection Limit (BDL)
to 8,600 mg/kg for TCE, from BDL to 2,700 mg/kg for PCE, from 9,300 to 220,000 mg/kg for
toluene, from BDL to 1,600 mg/kg for ethylbenzene, from 1,280 to 7,300 mg/kg for xylenes,
from BDL to 23,000 mg/kg for MEK, and from 1,400 to 66,000 mg/kg for MIBK.
The data provided in Table 7 show that a total of 72,083.8 pounds of total VOCs were recovered
from the soil stockpile in this application. This total includes VOCs recovered from the soil
stockpile and the excavation and screening emissions. According to the OSC, 75 to 80% of the
VOCs were recovered from the soil stockpile, with the remainder recovered from the excavation
and screening processes. Table 7 also shows that the quantity of VOCs recovered varied over the
course of the application. During the first six and latter three weeks of the application, total
VOC recoveries averaged 4,400 Ibs/week. However, during weeks 7, 8, and 9, total VOC
recoveries averaged 11,000 Ibs/week, approximately 2.5 times greater. According to the OSC,
this was likely due to variations in VOC concentrations in the soils in the surface impoundment.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
29
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I TREATMENT SYSTEM PERFORMANCE (CONT.}
Performance Data Assessment (cont.)
• Basket Creek Surface Impoundment Site, Page 17 of 24
Table 8 shows that toluene was the largest quantity VOC recovered during this application,
accounting for approximately 80% of the total VOCs recovered. MIBK accounted for
approximately 11% of the recovered VOC, with the remainder consisting of TCE, PCE, benzene,
ethylbenzene, xylenes, MEK, and chlorobenzene. These results are consistent with the data
shown in Table 1 for soil sampling in the surface impoundment prior to this application. As
shown in Table 1, for the composite sample collected in May 1991, toluene was present in the
highest concentration (11,000 mg/kg), followed by MIBK at 4,700 mg/kg.
The thermal oxidizer destruction efficiency data show that, while the monthly average inlet
concentrations varied from 10,944 to 432,960 ppmv, the oxidizer consistently met the
requirement for a destruction efficiency of at least 95%. In addition, during December 1992,
January 1993, and February 1993, when the monthly average inlet concentrations were greater
than 100,000 ppmv, the destruction efficiency was at least 98%.
Performance Data Completeness
Analytical data are available for the following: 1) the concentrations of contaminants in the
surface impoundment prior to treatment; 2) the concentrations of contaminants in the soil
stockpile after treatment was completed; 3) the quantity of total and specific VOCs recovered
during 12 weeks of system operation; 4) the destruction efficiency for the thermal oxidizer; and
5) air emission results for inside the operations building, around the building perimeter, and at
off-site locations.
No data are available to characterize the concentrations of contaminants in the soil stockpile just
prior to system operation, or to compare with concentrations after treatment was completed.
Performance Data Quality
Quality assurance/quality control (QA/QC) activities for this application included use of standard
EPA protocols for sampling, including chain-of-custody procedures for sample transport, use of
standard analytical methods such as SW-846 Methods 8260 and 1311 for TCLP analysis of
volatiles, Methods 6010 and 1311 for TCLP analysis of metals (except mercury), Methods 7470
and 1311 for TCLP analysis of mercury, and use of matrix spike, matrix spike duplicate, and
blank samples. Limited exceptions to protocol were noted by the analytical laboratory for some
QA/QC activities. For example, for 3 of the 14 soil stockpile grid samples (AB-12,11, CD-
12,11, and EF-12,11), the TCE and toluene matrix spike recoveries were not able to be
determined by the analytical laboratory because of co-eluting interferences. [2] These
exceptions are not believed to substantially impact the results for this application.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
30
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• Basket Creek Surface Impoundment Site, Page 18 of 24
I TREATMENT SYSTEM COST
Procurement Process
EPA was supported in the remediation at the Basket Creek Surface Impoundment site by OHM
under a Response Engineering and Analytical Contract (REAC), and by Roy F. Weston under a
Technical Assistance Team (TAT) contract and a REAC. OHM supported EPA in system
design, construction, and operation, and used several subcontractors for these efforts. Under the
TAT contract, Weston was tasked to perform, soil sampling (prior to treatment) and air
monitoring during treatment. Under the REAC contract, Weston was tasked to perform the
thermal oxidizer trial burn. Both OHM and Weston summarized results from the application.
[2,4]
Subcontracts for equipment purchases and leases were bid competitively in this application. [13]
Treatment System Cost [1,2, 12]
EPA reported total costs of approximately $2.2 million dollars for OHM and Weston during this
application, as shown in Table 10. Approximately 90% of the total costs were attributed to
OHM's activities. Table 10 shows the specific activities reported by EPA for OHM's and
Weston's costs. No additional information is available on the specific activities included under
each item (e.g., OHM's "other cost" of $1 million).
In order to standardize reporting of costs across projects, the total project cost was categorized
according to the format for an interagency Work Breakdown Structure (WBS). The WBS
specifies 9 before-treatment cost elements, 5 after-treatment cost elements, and 12 cost elements
that provide a detailed breakdown of costs for activities directly associated with treatment.
Following the WBS, the OSC for the Basket Creek site categorized the total project cost into
costs for before-treatment activities, shown in Table 11, costs directly attributed to treatment
activities, shown in Table 12, and costs for after-treatment activities, shown in Table 13.
These costs were categorized using best professional judgement and experience with the
application, as detailed invoices or other quantitative data were not available for this report. As
such, the individual cost elements are estimated values based on an actual total project cost.
In categorizing the costs for this application according to the WBS, the OSC identified specific
cost elements within the WBS and allocated a percentage of the total cost to each item. Tables
11,12, and 13 show the cost elements identified by the OSC exactly as they appear in the WBS,
and the specific activities identified by the OSC within each cost element. For example, under
"site work" in Table 11, the OSC identified costs for excavation and soil preparation.
As shown in Table 11, approximately $1,300,000 were expended in this application for before-
treatment activities, such as monitoring, sampling, testing, and analysis, site work, and air
pollution/gas collection and control. Table 12 shows $660,000 expended for activities directly
attributed to treatment, consisting of short-term operation (up to 3 years) and cost of ownership.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
31
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• Basket Creek Surface Impoundment Site, Page 19 of 24
| TREATMENT SYSTEM COST (CONT.)|
Treatment System Cost (cont.) [1,2,12]
Table 13 shows $220,000 expended for after-treatment activities including disposal of residuals,
site restoration, and demobilization.
Table 10. Total Costs Reported by EPA [2]
Activity
- • . ' : -" ActttStl COSt ($) " '":": :' ' ' "C ' 'x •' '.
OHM
Personnel
Equipment
Analytical
Transportation and Disposal
Other Cost
TOTAL OHM COST
797,246.65
67,809.90
40,471.54
122,472.34
1,011,333.80
2,039,334.23*
Wcston
Labor
Travel
Other Direct Costs
Project Administration
TOTAL WESTON COST
TOTAL PROJECT COST
98,736.06
136.38
27,691.78
101,498.39
228,062.61**
2,267,396.80
"These costs are totalled from four delivery orders (4003-F4-005,4001-F4-025,4001-F4-027, and
4001-F4-038), and are current as of August 1993.
**These costs are the actual direct and indirect cost incurred on this project from October 1990 through
October 1994, and are current as of August 1993.
Table 11. Before-Trcacment Costs Shown Using WBS* [1,12]
Cost Element
Monitoring, Sampling, Testing, and Analysis
- Sampling, Analytical, Miscellaneous
Site Work
- Excavation and Soil Preparation (Screening)
Air Pollution/Gas Collection and Control
- Enclosure, Air Handling System, and Part of the Incinerator
Total
Estimated Cost ($)
260,000
390,000
650,000
1,300,000
US. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
32
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• Basket Creek Surface Impoundment Site, Page 20 of 24
| TREATMENT SYSTEM COST (CONT.)|
Treatment System Cost (cont.) [1,2,12]
Table 12. Treatment Costs Shown Using WBS* [1,12]
'- : , " Cost Element * -
' • , -I ' !•' , *, 1,
Operation (Short-Term - Up to 3 Years)
- Operating Costs, Personnel
Cost of Ownership
- SVE System, Part of the Incinerator
Total
Estimated Cost ($)
130,000
530,000
660,000
Table 13. After Treatment Costs Shown Using WBS* [1,12]
Cost Element > ",-, ' , - ;/t
Disposal (Commercial)
Site Restoration
Demobilization
Total
Estimated Cost ($)
130,000
22,000
68,000
220,000
*The costs shown in Tables 11, 12, and 13 were categorized by the OSC according to the WBS using best
professional judgement and experience with the application. The OSC indicated that part of the costs for
the incinerator were incurred for treatment of vapors extracted by the excavation and power screening steps
(before-treatment costs) and part for treatment of vapors from the soil stockpile (treatment costs).
The $660,000 in costs directly attributed to treatment activities corresponds to $413 per cubic
yard of soil treated (1,600 cubic yards of soil in the surface impoundment), $275 per ton of soil
treated (2,400 tons), and $9.20 per pound of VOC removed (approximately 72,000 pounds VOC
removed). These unit costs reflect treatment of a relatively small quantity of soil that contained
a relatively high concentration of contaminants.
Cost Data Quality
The total costs described above represent actual costs for this treatment application as reported
by EPA. Limited information is available on the specific activities included within the total cost
figure.
The costs categorized according to the WBS shown in Tables 11, 12, and 13 are estimated values
based on information provided by the OSC for this application. The estimates are based on best
professional judgement and experience with the application.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
33
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OBSERVATIONS AND LESSONS LEARNED
Cost Observations and Lessons Learned
• Basket Creek Surface Impoundment Site, Page 21 of 24
• Approximately $2.2 million were expended in this application, including $1.3 million for
before-treatment activities, $660,000 for activities directly attributed to treatment, and
$220,000 for after-treatment activities, including off-site disposal of treated soil.
Because this ex situ application at Basket Creek was required to be performed in an
enclosure, approximately $650,000 in before-treatment costs were expended for the
building (enclosure), air handling system, and treatment of building vapors in an
incinerator.
• The $660,000 in costs directly attributed to treatment activities corresponds to $413 per
cubic yard of soil treated (1,600 cubic yards), $275 per ton of soil treated (2,400 tons),
and $9.20 per pound of VOC removed (approximately 72,000 pounds VOC removed).
These unit costs reflect treatment of a relatively small quantity of soil that contained a
relatively high concentration of contaminants.
• The $2.2 million expended for the treatment application at Basket Creek was less than
would have been expended for off-site incineration of soil. Based on bids ranging from
$2,500 to $2,800 per ton, the projected cost for off-site incineration of 2,400 tons of soil
would have been $6 to 6.7 million.
Performance Observations and Lessons Learned
• The soil stockpile analytical data indicates that the soil treatment targets were met for all
14 sampling grids after 6 months of treatment.
• In the 14 sampling grids, the TCLP results for TCE were consistently less than 0.1 mg/L,
for PCE less than 0.3 mg/L, for benzene less than 0.03 mg/L, for MEK less than 2.0
mg/L, and for lead less than 2.0 mg/L. The TCLP results for mercury were all less than
the reported detection limit. Total HOCs ranged from 0.055 to 20.3 mg/kg, and total
VOCs from 0.142 to 1,570.7 mg/kg.
• The analytical data show that there were variations in concentrations among the 14 grid
samples. For example, the total VOC data show a range over four orders of magnitude
in the 14 grid samples, from 0.142 to 1,570.7 mg/kg.
• A total of 72,083.8 pounds of total VOCs were recovered in this application. This total
includes VOCs recovered from the soil stockpile (75-80%) and the excavation and
screening emissions (20-25%).
• The quantity of VOCs recovered varied over the course of the application. During the
first six and latter three weeks of the application, total VOC recoveries averaged 4,400
Ibs/week. However, during weeks 7, 8, and 9, total VOC recoveries averaged 11,000
Ibs/week, approximately 2.5 times greater. According to the OSC, this was likely due to
variations in VOC concentrations in the soils in the surface impoundment.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
34
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1 Basket Creek Surface Impoundment Site, Page 22 of 24
OBSERVATIONS AND LESSONS LEARNED (CONT.)
Performance Observations and Lessons Learned (cont.)
• Toluene was the largest quantity VOC recovered during this application, accounting for
approximately 80% of the total VOCs recovered. MIBK accounted for approximately
11% of the recovered VOC, with the remainder consisting of TCE, PCE, benzene,
ethylbenzene, xylenes, MEK, and chlorobenzene. Toluene and MIBK were also the
contaminants measured in the highest concentrations in soil samples collected from the
impoundment prior to the remediation.
• The analytical data show that the thermal oxidizer consistently achieved a destruction
efficiency of at least 95% over 12 weeks of system operation. In addition, during
December 1992, January 1993, and February 1993, when the monthly average inlet
concentrations were greater than 100,000 ppmv, the destruction efficiency was at least
98%.
• Air emission results show elevated levels of VOCs inside the operations building;
however, the concentration never exceeded 10% of the LEL or 500 ppm total
hydrocarbons in the air, and work did not have to be stopped because of elevated levels
in the building. In addition, no VOCs were detected during hourly air monitoring
surveys around the perimeter of the operations building or in off-site high volume air
samples.
• A comparison of data from soil samples in the impoundment prior to excavation and the
soil stockpile after treatment show that the TCLP concentrations for TCE and MEK in
the 14 sampling grids after treatment (TCE less than 0.1 mg/L; MEK less than 2.0 mg/L)
were less than the TCLP concentrations in the pre-excavation samples. For example, in
May 1991, TCE was measured as less than 11.0 mg/L, and MEK as 280 mg/L. However,
it should be noted that there are no samples of untreated soil from the stockpile.
• While SVE was not expected to reduce the concentrations of lead and mercury in the
soil, a comparison of data from soil samples in the surface impoundments prior to
excavation and the soil stockpile after treatment show the TCLP concentrations for lead
in the 14 sampling grids after treatment were less than the concentrations in the pre-
excavation samples (for example, 32.6 mg/L before-treatment in May 1991,0.25-1.9
mg/L after-treatment). However, as for the VOCs, there are no samples of untreated soil
from the stockpile. As such, the OSC believed the reduction is due to the pre-excavation
samples not being representative of the area of contamination as a whole, rather than as a
result of treatment.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
35
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• Basket Creek Surface Impoundment Site, Page 23 of 24
•H OBSERVATIONS AND LESSONS LEARNED (CONT.)
Other Observations and Lessons Learned
• EPA selected ex situ SVE for this application. In situ SVE was ruled out because of the
low permeability of the contaminated soil. Low temperature thermal desorption was
eliminated because the soil was too highly contaminated, and, during a treatability study,
a soil sample ignited. Incineration was ruled out because it was estimated to be
approximately three times more expensive than the selected remedy.
• The OSC made the following observations about this application:
The excavation and power screening activities associated with the ex situ SVE
application greatly increased the soil permeability. The power screening
shredded soil clumps and broke up the soil. Soil permeability was not, however,
measured after the power screening.
There were limitations associated with the materials of construction used for the
soil stockpile. While building the soil stockpile, there was trouble maintaining
the spacing of the horizontal wells because they were made out of PVC and
would bend under the weight of the soil. The OSC indicated that carbon steel
pipes would have been more rigid, but would have cost more.
It was important to oversize the air handling system for venting the building.
The oversized system helped to prevent safety problems due to an explosive
atmosphere in the building and in the ductwork. For example, during excavation
of hot spots, VOC concentrations in the ductwork of the building vent system
were greater than 1,000 ppm.
Excavation within an enclosure takes much longer than outside due to the space
constraints. The OSC indicated that the excavation at Basket Creek would have
been completed within a few days. However, excavation within the enclosure at
Basket Creek took 3 months.
HB REFERENCES I
1. "Controlling Fugitive Emissions from Excavation of Contaminated Soil: A Case Study;" R.
Donald Rigger, On-Scene Coordinator, U.S. Environmental Protection Agency Region 4,345
Courtland Street, N.E., Atlanta, Georgia, 30365; undated.
2. Formal Report. Basket Creek Surface Impoundment Site. Douglasville, Douglas County,
Georgia. Roy F. Weston, Incorporated. April 1, 1993.
3. Action Memorandum. Request for a Removal Action Ceiling Increase and Exemption from the
$2 Million Limit at the Basket Creek Surface Impoundment Site in Douglasville, Douglas
County, Georgia. April 11,1991.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
36
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• Basket Creek Surface Impoundment Site, Page 24 of 24
[ REFERENCES (CONT.)
4. Final Report. Basket Creek Impoundment Site. Douglasville, GA. Roy F. Weston, Inc.
December, 1991.
5. Vapor Recovery/Treatment Progress Report. Basket Creek Surface Impoundment. Douglasville,
Douglas County, GA. OHM Remediation Services Corp., Norcross, Georgia.
6. Final Report. Stack Sampling and Air Quality Dispersion Modeling. Basket Creek site.
Douglasville, Georgia. Roy F. Weston, Inc. March 1993.
7. Basket Creek Impoundment Site. Douglas County, Georgia. Thermal Oxidizer Source Emission
Test Report. Volume I. Roy F. Weston, Inc. March 1993.
8. Site Specific Test Plan. Emission Testing on Thermal Oxidizer Exhaust Stack. Basket Creek
Impoundment Site. Douglas County, Georgia. August 1992.
9. Basket Creek Drum Disposal Site. Douglasville, Douglas County, Georgia. Site Investigation.
May 2, 1990.
10. Letter from Don Rigger, OSC, to Mr. Nolan. January 15, 1993.
11. Meeting Notes. Meeting on 9/26/95 between Tim McLaughlin, Radian Corporation, and Don
Rigger, OSC.
12. Meeting Notes. Meeting on 9/27/95 between Tim McLaughlin, Radian Corporation, and Don
Rigger, OSC.
13. Comments from Don Rigger, OSC, provided to L. Fiedler, EPA, March 8, 1996.
14. OHM Corporation brochure, "Ex Situ Soil Vapor Extraction and VOC Treatment Project,
USEPA Basket Creek Surface Impoundment, Douglasville, Georgia," not dated.
Analysis Preparation
This case study was prepared for the U.S. Environmental Protection Agency's Office of Solid
Waste and Emergency Response, Technology Innovation Office. Assistance was provided by
Radian Corporation under EPA Contract No. 68-W3-0001 and U.S. Army Corps of Engineers
Contract No. DACA45-96-D-0016.
u.s. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
37
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Soil Vapor Extraction at the Sacramento Army Depot
Superfund Site, Burn Pits Operable Unit,
Sacramento, California
39
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Case Study Abstract
Soil Vapor Extraction at the Sacramento Army Depot Superfund Site*
Burn Pits Operable Unit, Sacramento, California
Site Name:
Sacramento Army Depot Superfund
Site, Burn Pits Operable Unit
Location:
Sacramento, California
Contaminants:
Organic Compounds; Volatiles-Halogenated
- Trichloroethene (TCE), tetrachloroethene
(PCE), and 1,2-dichloroethene (DCE) each
less than 0.01 mg/kg
Period of Operation:
May 1994 - September 1995
Cleanup Type:
Full-scale cleanup
Vendor:
Ashok Gopinath
OHM Remediation Services Corp.
5731W. Las Positas Blvd.
Pleasanton, CA 94588
(510) 227-1100
SIC Code:
3471: Electroplating, Plating,
Polishing, Anodizing, and Coloring
3479: Coating, Engraving, and
Allied Services, Not Elsewhere
Classified
Technology:
Soil Vapor Extraction
- System was OHM's patented Fluid
Injection-Vacuum Extraction (FIVE)
technology
- Included 10 shallow extraction/injection
wells, 12 deep wells, 1 horizontal well,
HEPA filters, and 2 trains of GAC units
- Shallow wells screened 10-25 ft below
ground surface (bgs)
- Deep wells screened 50-80 and 17-47 ft bgs
- Some wells operated as injection wells and
others as extraction wells
Cleanup Authority:
CERCLA
- Record of Decision Date
2/26/93
- U.S. Army Lead
Point of Contact:
Martin Mezquita
USEPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-2393
Waste Source:
Disposal Pit; Incineration Residuals
Handling
Purpose/Significance of
Application:
Full-scale application combining
fluid injection and vacuum
extraction wells in a complex
subsurface environment.
Type/Quantity of Media Treated:
Soil
- 247,900 cubic yards
- Subsurface consists of interbedded sands, silts, and clays, with some coarse
gravels
- Six fades identified during site investigation
Regulatory Requirements/Cleanup Goals:
- Soil cleanup standards for TCE, PCE, and DCE of 0.005 mg/kg
- Air emission limits identified for TCE, PCE, and DCE
Results:
- Soil cleanup goals met within 14 months of system operation
- Concentrations in treated soil were: TCE - 0.0021 mg/kg; PCE - 0.0013 mg/kg; and DCE - 0.0027 mg/kg
- Approximately 138 Ibs of TCE, PCE, and DCE extracted
Cost Factors:
- Actual costs of $865,873 included $195,000 for before-treatment activities (drilling, soil gas survey, confirmatory
borings, and chemical testing), and $670,500 for activities directly attributed to treatment (design, mobilization,
construction, start-up/testing/permitting, SVE operations and maintenance, and demobilization)
- The unit cost for activities directly attributed to treatment was $2.70/yd3 of soil treated, and $4,858/lb of VOC
removed
40
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Case Study Abstract
Soil Vapor Extraction at the Sacramento Army Depot Superfund Site,
Burn Pits Operable Unit, Sacramento, California (Continued)
Description:
The Burn Pits Operable Unit at SAAD was the location of two rectangular trenches constructed in the late 1950s and
used intermittently as incineration pits until 1966. Materials reportedly buried and/or burned in the pits included
plating shop wastes, oil and grease, batteries, and construction debris. Remedial investigations conducted from 1990 to
1993 showed average soil contaminant concentrations for TCE ranging from 0.0029 to 0.0069 mg/kg, PCE from 0.0029
to 0.0079 mg/kg, and DCE from 0.0038 to 0.0055 mg/kg. In addition, the Army's basewide contractor estimated the
total mass of selected contaminants in the operable unit as follows: TCE - 22.3 Ibs; PCE - 7.1 Ibs; and DCE - 39.3 Ibs.
A Record of Decision (ROD) addressing the Burn Pits O.U. was signed in March 1993. OHM's patented fluid
injection/vapor extraction (FIVE) system was used to remediate the Burn Pits O.U. In the FIVE technology,
pressurized air is injected into vadose zone soils to produce relatively larger subsurface pressure gradients and higher
flow rates of extracted vapors than would be achieved solely with using vapor extraction technology. The vendor stated
that this system "enhanced subsurface volatilization and shortened the period of remediation," however, no data were
provided to support this statement. The FIVE system used at the SAAD Burn Pits consisted of 10 shallow
extraction/injection wells, 12 deep extraction/injection wells, 1 horizontal extraction/injection well, air injection piping,
vapor monitoring wells, liquid/vapor separators, high efficiency particulate filters, vapor phase granular activated carbon,
and positive displacement blowers. The wells were screened up to 80 feet below ground surface.
Confirmatory soil borings showed that the average concentrations for each of the three target contaminants was less
than the cleanup standards set in the ROD. TCE was reduced to an average concentration of 0.0021 mg/kg, PCE to
0.0013 mg/kg, and DCE to 0.0027 mg/kg. Approximately 138 Ibs of TCE, PCE, and DCE were extracted during this
application, or roughly two times as much VOCs as originally estimated to be present at the operable unit. Possible
reasons for the discrepancy between the original estimate and the actual amount recovered identified by the treatment
vendor include inaccuracies in the original estimate and for 1,2-DCE, a reductive dehalogenation mechanism that
occurred in situ. According to the vendor, the use of the FIVE technology "enhanced subsurface volatilization and
shortened the period of remediation"; however, no additional information comparing this technology to other SVE
systems was provided.
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page i of 28 •
I COST AND PERFORMANCE REPORT |
I EXECUTIVE SUMMARY
This report presents cost and performance data for a soil vapor extraction (SVE) system at the
Bum Pits Operable Unit, Sacramento Army Depot (SAAD) Superfund site in Sacramento
California. The SVE system was used at the Burn Pits Operable Unit to treat soil contaminated
with halogenated volatile organic compounds (VOCs), specifically trichloroethene (TCE),
tetrachloroethene (PCE), and 1,2-dichloroethene (DCE).
The Bum Pits Operable Unit at SAAD was the location of two rectangular trenches constructed
in the late 1950s and used intermittently as incineration pits until 1966. Materials reportedly
buried and/or burned in the pits included plating shop wastes, oil and grease, batteries, and
construction debris. Remedial investigations conducted from 1990 to 1993 showed average soil
contaminant concentrations for TCE ranging from 0.0029 to 0.0069 mg/kg, PCE from 0.0029 to
0.0079 mg/kg, and DCE from 0.0038 to 0.0055 mg/kg. In addition, the Army's basewide
contractor estimated the total mass of selected contaminants in the operable unit as follows: TCE
- 22.3 pounds (Ibs); PCE - 7.1 Ibs; and DCE - 39.3 Ibs.
A Record of Decision (ROD) addressing the Burn Pits Operable Unit was signed in March 1993
and specified soil cleanup standards of 0.005 mg/kg for each of the three VOCs identified above.
Although not shown in the ROD, the treatment vendor reported the following air emission rate
limits for this application: TCE - 0.0043 Ibs/hr; PCE - 0.003 Ibs/hr; and 1,2-DCE - 0.003 Ibs/hr.
The SVE system used was a patented fluid injection/vapor extraction (FIVE) system. In the
FIVE technology, pressurized air is injected into vadose zone soils to produce relatively larger
subsurface pressure gradients and higher flow rates of extracted vapors than would be achieved
solely with using vapor extraction technology. The vendor stated that this system "enhanced
subsurface volatilization and shortened the period of remediation," however, no data were
provided to support this statement. The FIVE system used at the SAAD Burn Pits consisted of
10 shallow extraction/injection wells, 12 deep extraction/injection wells, 1 horizontal
extraction/injection well, air injection piping, vapor monitoring wells, liquid/vapor separators,
high efficiency paniculate filters, vapor phase granular activated carbon, and positive
displacement blowers. The wells were screened up to 80 feet below ground surface.
The FIVE system was operated from May 1994 to January 1995, and again from March 1995 to
September 1995, for a total of 347 days of run tune. Confirmatory soil borings collected in
September 1995 showed that the average concentrations for each of the three target contaminants
was less than the cleanup standards set hi the ROD. TCE was reduced to an average
concentration of 0.0021 mg/kg, PCE to 0.0013 mg/kg, and DCE to 0.0027 mg/kg. Analytical
data collected in this application showed that the rate of VOC removal decreased over the course
of the remediation. For example, the VOC extraction rate decreased from ah average of 4
Ibs/day over the first 20 days of system run time to less than 1 Ib/day after 40 days of system run
time. Approximately 138 Ibs of VOCs were extracted during this application, or roughly two
times as much VOCs as originally estimated to be present at the operable unit. The vendor
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Sacramento Army Depot Superfiind Site, Burn Pits Operable Unit, Page ii of 28 •
I EXECUTIVE SUMMARY (CONT.) |
indicated that a possible reason for this result is an inaccuracy in the original estimate for the
operable unit.
The total actual costs for this application were approximately $865,873. Of this total,
approximately $195,000 were expended in before-treatment costs for drilling, soil gas survey,
confirmatory boring, and chemical testing, and approximately $670,500 were expended for
activities directly attributed to treatment, such as design, mobilization, construction, start-
up/testing/permitting, SVE operations and maintenance, and demobilization. The $670,500 in
costs directly attributed to treatment corresponds to $2.70 per cubic yard of soil treated (247,900
cubic yards) and $4,858 per pound of target VOC extracted (138 pounds of TCE, PCE, and
DCE). These unit costs show that this application treated a relatively large volume of soil
contaminated with relatively small concentrations of target VOCs.
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I SITE INFORMATION
Identifying Information:
Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 1 of 28-
Sacramento Army Depot
Sacramento, California
Operable Unit: Bum Pits
CERCLIS* CA0210020780
ROD Date: February 26, 1993
Treatment Application;
Type of Action: Remedial
Treatability Study Associated with Application? No
EPA SITE Program Test Associated with Application? No
Period of Operation: May 1994 - September 1995
Quantity of Material Treated During Application: 247,900 cubic yards of soil. The burn pits
contain approximately 16,900 cubic yards of contaminated soil, and the surrounding area
contains approximately 231,000 cubic yards of contaminated soil. [3] This quantity is based on
an area of 78,750 square feet and a depth of 85 feet. [12]
Background [1,2]
Historical Activity that Contributed to Contamination at the Site: Metal-plating and
painting operations
Corresponding SIC Code(s):
3471: Electroplating, Plating, Polishing, Anodizing, and Coloring
3479: Coating, Engraving, and Allied Services, Not Elsewhere Classified
Waste Management Practice that Contributed to Contamination: Disposal Pit; Incineration
Residuals Handling
Site History: The Sacramento Army Depot (SAAD) is a 485-acre U.S. Army support facility,
located in Sacramento, California, as shown on Figure 1. Current and historical operations
conducted at the facility include electro-optics equipment repair, emergency manufacturing of
parts, shelter repair, metal plating and treatment, and painting. In conjunction with these
operations, the Army maintained unlined oxidation lagoons and burn pits, a battery disposal area,
areas designated for mixing pesticides, and a firefighter training area.
In 1978 and 1979, the U.S. Army Toxic and Hazardous Materials Agency (USATHMA)
identified several areas at SAAD, based on historical data, where the use, storage, treatment, and
disposal of toxic substances may have contributed to contamination of soil and/or groundwater.
In 1981, the Army and the California Central Valley Regional Water Quality Control Board
(CVRWQCB)
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 2 of 28-
| SITE INFORMATION (CONT.)
Background (cont.)
conducted investigations of soil and
groundwater in the areas identified by
USATHMA. The groundwater under the
southwest corner of SAAD was determined
to be contaminated with volatile organic
compounds (VOCs) with the burn pits
suspected as the main source of
groundwater contamination.
Two burn pits were constructed at SAAD
in the late 1950s, and served intermittently
as incineration pits until 1966. The two
burn pits are rectangular trenches, referred
to as the "North Burn Pits" and "South
Bum Pits." Each burn pit is about 30 feet
wide, 330 to 345 feet long, and
approximately 16 to 19 feet deep.
Materials that were reportedly buried
and/or burned in the burn pits include
plating shop wastes, oil and grease,
batteries, and uncontaminated construction
debris. As of 1993, the burn pits were
filled to the ground surface with soil and
debris, including
scrap metal,
concrete, wood,
and glass.
Sacramento Anny Depot
Superfund Site
Sacramento, California
Figure 1. Site Location
The Burn Pits
Operable Unit
occupies
approximately 2
acres in the
southwest portion
of SAAD, and
consists of the
North and South
Burn Pits and
surrounding area.
The operable unit
is approximately 85 feet deep, extending through
Figure 2. Location of Burn Pits at SAAD [1]
• • ^
EU
LEGEND
SITE BOUNDARY
BUILDINGS/STRUCTURES
j .
DO
r
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Sacramento Army Depot Superfund Site, Bum Pits Operable Unit, Page 3 of 28-
| SITE INFORMATION (CONT.)
Background (conk)
the vadose zone to the water table. A site map of the SAAD facility showing the location of the
bum pits operable unit is shown on Figure 2.
The 1981 investigations also identified six other potential areas of contamination: the Tank 2
area, the oxidation lagoons, the Building 320 leach field, the pesticide mix area, the firefighter
training area, and the battery disposal well. Operable units were defined for each of these areas
of contamination. A remedial investigation identified several volatile and non-volatile organic
and metal constituents in the soil at SAAD. As a result of these investigations, SAAD was
placed on the National Priorities List (NPL), effective August 21,1987.
Regulatory Context: In December 1988, the Army, EPA, and the State of California signed a
Federal Facility Agreement (FFA) under CERCLA Section 120, to address the entire facility,
including the contaminated groundwater and the following seven areas of suspected
contamination on the SAAD facility:
• Burn Pits;
• Tank2;
• Oxidation Lagoons;
• Building 320 Leach Field;
• Pesticide Mix Area;
• Firefighter Training Area; and
• Battery Disposal Well.
The FFA also required a RCRA Facility Assessment to identify other solid waste management
units that needed further characterization and cleanup. Under the FFA, the U.S. Army was the
lead agency responsible for implementing the environmental response activities at SAAD.
A Record of Decision (ROD) for the Burn Pits Operable Unit was signed by the Army,
California EPA, and the U.S. EPA in March 1993. The ROD required:
• Soil vapor extraction (SVE) of all soils in the Burn Pits Operable Unit;
• Excavation of soils which contained non-volatile contaminants;
• Stabilization of the excavated soils;
• Backfill of the excavation with stabilized soil; and
• Implementation of institutional controls in the form of a deed restriction and notices, to
prohibit future disturbances of the stabilized soil mass.
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 4 of 28
I SITE INFORMATION (CONT.)
Background (cont.)
The ROD identified soil cleanup standards of 0.005 mg/kg for three VOCs: trichloroethene
(TCE), tetrachloroethene (PCE), and 1,2-dichloroethene (1,2-DCE).
For non-volatile contaminants, the ROD required soils to be solidified so that the waste extract
did not exceed the following levels: arsenic, 5 mg/L; cadmium, 1 mg/L; chromium, 5 mg/L; and
lead, 5 mg/L.
Remedy Selection: Six alternatives were considered for remediation of the burn pits operable
unit. The remedy described above was selected based on a comparative analysis of the six
alternatives, in terms of short- and long-term effectiveness, permanence, reduction of toxicity,
mobility, and volume, implementability, and cost.
Site Logistics/Contacts
Site Management: U.S. Army-lead
Oversight: EPA
Remedial Project Manager:
Marlin Mezquita
U.S. EPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-2393
U.S. Army Project Manager:
Dan Oburn (primary contact for this
application)
U.S. ACE, Sacramento District
1325 J Street
Sacramento, CA 95814-2922
(916) 557-7936
Treatment Vendor:
Ashok Gopinath
OHM Remediation Services Corp.
5731 W. Las Positas Blvd.
Pleasanton, CA 94588
(510)227-1100
Basewide Contractor:
Pamela Wee
Kleinfelder Inc.
3077 File Circle
Sacramento, CA 95827
(916) 366-1701
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I MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the Treatment System: Soil (in situ)
Contaminant Characterization
Primary Contaminant Groups: Organic Compounds; Volatiles-Halogenated
The Army divided the Burn Pits Operable Unit into five "units" to evaluate health risks and
develop remediation plans,. The average concentrations of selected organics and metals in the
five units were quantified during a 1990-1993 remedial investigation (RI), as shown in Table 1.
In addition, as part of the remediation planning process, the mass of the three VOCs present in
the operable unit was estimated as follows (5):
• trichloroethene (TCE) - 22.3 Ibs;
• tetrachloroethene (PCE) - 7.1 Ibs; and
1,2-dichIoroethene (1,2-DCE) - 39.3 Ibs.
Table 1. Summary of Average Soil Concentrations of Organics and Metals
Measured During 1990-1993 Remedial Investigation [1]
Organics
Trichloroethene
Tetrachloroethene
I ,2-Dichloroethene
Ethylbcnzene
Toluene
Xylenc
Di-n-butyl phthalate
Arochlor 1254
Arochlor 1260
2,3,7,8-TCDD equivalent
Average Concentrations*
(mg/kg)
0.0029 - 0.0069
0.0029 - 0.0079
0.0038-0.0055
0.003 - 0.0061
0.0029 - 0.0092
0.0029 - 0.0072
0.1721 - 0.2147
0.14
0.06
0.000098
Metals
Antimony
Arsenic
Boron
Cadmium
Chromium (total)
Copper
Lead
Manganese
Mercury
Molybdenum
Silver
Zinc
Average Concentrations41
(mg/kg)
6.0
6.0
6.5
4.9
51.9
68.4
64.5
380
0.1
1.1
0.23
158.6
* Average concentradons for volatile organics are shown in Table 1 as a range of concentrations quantified in the five units of the
Burn Pits Operable Unit. For arochlors 1254 and 1260,2,3,7,8-TCDD, and all metals shown, an average concentration was
identified only for one of the five units. For these constituents, only a single value is shown in Table 1.
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I MATRIX DESCRIPTION (CONT.) I
Contaminant Characterization (cont.)
At an unspecified date prior to remediation, OHM collected "baseline" soil samples. These
samples were collected from a depth of 80 feet bgs. Soil samples were collected in brass sleeves
placed inside a split-spoon sampler and sent to an off-site laboratory certified by the state of
California. The soil samples were analyzed by USEPA Method 8240 for volatile organic
compounds. In the baseline soil samples, the concentrations of TCE, PCE, and 1,2-DCE were all
below the analytical detection limits (0.001 mg/kg for these samples), with one exception. In
well SVW13, TCE was detected at a concentration of 0.012 mg/kg. The baseline samples
contained lower concentrations of VOCs in soil than measured during the RI (see Table 1).
Matrix Characteristics Affecting Treatment Cost or Performance
The major matrix characteristics affecting cost or performance for this technology and the values
measured for each are shown in Table 2.
Table 2. Matrix Characteristics [3, 12]
Parameter " *• „ ^
Soil Classification
Clay Content and/or Particle Size
Distribution
Moisture Content
Air Permeability
Porosity
Total Organic Carbon
Nonaqueous Phase Liquids
* ' ' *„ Value \
See discussion under site geology
See discussion under site geology
Not measured but vendor estimated moisture
content would be between 5-15%
Not measured
Not measured
Not measured
Not present
Measurement
Method
N/A
N/A
N/A
N/A
Not reported
N/A - Not applicable because value not measured.
Site Geology/Stratigraphy
SAAD is located in the Great Valley of California, a broad asymmetric trough filled with a thick
assemblage of flat-lying marine and non-marine sediments. The most recent formations
deposited in the Great Valley are non-marine sediments derived from the Sierra Nevada foothills
and mountains on the west side of the valley and from the Coast Ranges on the east side of the
valley. [1]
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Sacramento Army Depot Superfund Site, Bum Pits Operable Unit, Page 7 of 28 •
I MATRIX DESCRIPTION (CONT.) I
Site Geology/Stratigraphy (cont.)
The upper 250 feet of sediments under SAAD consist of interbedded sands, silts, and clays, with
some coarse gravels underlying the north side of the facility at an approximate depth of 40 feet.
Older buried stream channels exist at various locations and depths in the area. These streams
have deposited materials ranging in size from gravel to clay. Multiple discontinuous hardpans
(cemented clays), representing ancient soil horizons, exist throughout the site. [1]
As part of this remediation, the treatment vendor performed extensive investigations into site
geology, including a "fades analysis" to collect data concerning the sedimentary structures and
scales of heterogeneity in strata within the vadose zone. The results of the facies analysis were
used in the design of the SVE system, particularly in the locations and depths of the extraction
wells. Facies were defined by grain size classified according to the Unified Soil Classification
System (USCS), color classified according to the Munsell chart, moisture, physical properties,
sorting, roundness, composition, contacts, and sedimentary structures. The facies analysis also
incorporated standard practices for description and identification of soils as described in ASTM
Method D2488-90. [3]
Six facies were identified during this investigation. The most common facies were artificial fill
(AF), sandy silt (ML), silty sand (SM), and sand (SP). The least common facies were clay (CL)
and clayey sand (SC). Table 3 shows the range of percentages of facies measured in extraction
well borings. [3] According to the vendor, the subsurface at the Burn Pits consisted mainly of
debris till 20 feet and then silty sand to sandy silt to sand. [12]
Table 3. Range of Percentages of Facies in Extraction Well Borings [3]
Facie
Sandy Silt (ML)
Silty Sand (SM)
- weak to moderate cementation
- moderate to strong cementation
Sand (SP)
Clay (CL)
Range of Percentages of Facies ','
in Extraction Wells (%) . VI
3-66
10-53
3-52
2-55
2-18
The California Department of Water Resources has divided the water-bearing sediments in the
soil at SAAD into two hydraulically isolated sections: the superjacent (upper) series, at depths
of about 80 to 250 feet beneath the site; and, the subjacent (lower) series, at depths below about
250 feet. [1]
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 8 of 28 •
| TREATMENT SYSTEM DESCRIPTIOI
Primary Treatment Technology Type; Soil Vapor Extraction
Supplemental Treatment Technology Type; Post-Treatment (Air) - Carbon Adsorption_^
Soil Vapor Extraction System Description and Operation
The SVE system used at the Burn Pits Operable Unit was OEM's patented fluid injection-
vacuum extraction (FIVE) technology. The FIVE technology consists of injection of pressurized
air into vadose zone soils, and extraction of vapors from vadose zone soils. This approach is
intended to produce relatively larger subsurface pressure gradients, and higher flow rates of
extracted vapors, than would be~achieved solely with using vapor extraction technology. [6]
System Design [5, 6, 12]
The SVE system used at the Burn Pits Operable Unit consisted of 10 shallow extraction/injection
wells, 12 deep (nested) extraction/injection wells, 1 horizontal extraction/injection well, air
injection piping, 6 "SEAMIST" monitoring wells (in-ground vapor measurement wells),
liquid/vapor separators, high efficiency paniculate (HEPA) filters, vapor phase granular
activated carbon, and positive displacement blowers. Figure 3 shows the locations of the
extraction/injection and monitoring wells relative to the North and South Burn Pits, and Figure 4
shows the SVE system.
N
t \
" V
\
'\
LEGEND
g£n OHM Nested Extraction Well
A OHM Shallow Extraction Well
SW-21
0 Horizontal Extraction Wen
SVW-14
-wrc SEAMIST Monitoring Wen
S*M Extraction Piping
Injection Piping
Perimeter Fence
SVW-1 8VW4
A A
> " "IS? ^\
\ ^- • •• H su., — \
\ 1 / SAW SVYM SWM J3 \
nlf t. t t _ T\
^. ..__ — 4
\ SW-M North Pit SVW-14 SVVM4
% I -«ww -mat -""Esvw-17
^ • . svw-s svww — ^
\\'\ \ \ A A SWM SVW-7 sui I J
\nVt. . ir t. Tt-t. ^_HTf
\ Vt^A \ SouftHl
* \\ 1^ I 1 1 1
v \ \ A svw^i A A A 4 k
" HSM-I 2tt«
0 10 60 100
Sc^lnFMl
Figure 3. Well Locations at Burn Pits Operable Unit [4]
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| TREATMENT SYSTEM DESCRIPTION (CONT.)I
Soil Vapor Extraction System Description and Operation (cont.)
The shallow wells contained a 15-foot well screen extending from 10 to 25 feet below ground
surface (bgs). The.screen interval was located in sediments adjacent to and below the bottom of
the artificial fill placed in the burn pits. In addition, a distinct well-cemented paleosol was
present at the site at a depth of approximately 20 to 25 feet bgs. The shallow wells were located
at this depth because the well-cemented paleosol had lower permeability than surrounding
sediments, and the downward migration of volatile and semivolatile organic compounds would
be temporarily restricted at this point.
To
Atmosphere
So
n Vapor
tl r.
II C
Liquid/Vapor
Separators
.
HEPA
Filters
Granular
Activated
Carbon
I
To Air
Injection
Wells
> Entrained Water and Solids
Extraction
Wats
(23 welts tola))
Figure 4. SVE System Schematic [Based on 2,6]
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 10 of 28 •
I TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont)
The deeper (nested) wells contained two screened areas in a single borehole, including 50 to 80
feet bgs, and 17 to 47 feet bgs. Two screen intervals were incorporated into the deeper well
design to enhance air flow and vapor extraction throughout the 80-foot vadose zone. The two
screened areas in the deeper wells were separated by a 2-foot (minimum thickness) bentonite
seal. A 325-foot horizontal well was included in the SVE system design because it had been
installed by a previous contractor (prior to OHM). It was not reported if this well was located in
the shallow or deep zones.
As shown in Figure 4, soil vapors extracted through the vertical and horizontal wells were first
treated using liquid/vapor separators. Entrained water (predominantly perched groundwater) and
solids were removed from the vapor stream in the separators. Water and solids removed from the
vapor stream were shipped off site to licensed disposal facilities in California. From the
separators, the vapor stream passed through the HEPA filters which were designed to remove
particulates larger than 0.3 microns.
The filtered vapor stream was then treated to remove VOCs using two parallel trains of vapor
phase granular activated carbon adsorption units (each containing primary and secondary units).
The granular activated carbon units contained a total of 8,400 pounds of carbon, and were
designed to have an overall VOC removal efficiency of 99 percent. The design basis for the
system assumed the following mass extraction rates:
TCE - 0.33 Ibs/hr;
PCE - 0.5 Ibs/hr; and
1,2-DCE - 0.23 Ibs/hr.
Treated vapor was injected into the vadose zone or released to the atmosphere using two rotary,
positive displacement blowers, each having a capacity of 1,000 scfm.
Injection Wells
The instrumentation and piping for each vertical and horizontal well was designed to be operated
in either extraction or injection mode. Valves were installed at the well head to isolate the piping
that was not in use. These valves were adjusted manually during system operation. In addition,
valves of the manifold system were adjusted to allow sections of the wellfield to operate in
pressure or vacuum mode or to control makeup vapor and the degree of re-injection to the vadose
zone.
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 11 of 28 •
I TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
System Controls
The FIVE system was designed with both mechanical and electrical controls. The controls
monitored parameters such as VOC concentration, temperature, and pressure at multiple points in
the system. The system was designed to shut off if a high pressure situation was encountered in
the process components.
System Operation [6,10,12]
Start-up Testing
During start-up testing, each individual well was developed independently to determine the
maximum flow rate and vacuum that could be expected. Analytical results for vapor samples
collected during start-up testing were used to predict mass extraction rates for each well.
According to the vendor, during this analytical testing, the highest concentrations of the target
compounds were found in the deep screen intervals of the nested wells to the north and west of
the north burn pit.
Operating Modes
Subsurface flow in the vadose zone was controlled by directing vapor transport between injection
(pressure mode) and extraction (vacuum mode) wells on opposite sides of the burn pits, and by
controlling flow between adjacent nested wells. All peripheral wells (SVW-1, 2, 3,4, 5, 10, 11,
12,13,16,17,20,21,22,23, and 24) were operated in vacuum mode. Interior wells (SVW-6, 7,
8, 9,18, and 19) were operated alternately in pressure and vacuum modes. Horizontal well
SVW-14, near the bottom of the North Burn Pit, was primarily operated in pressure mode to
drive volatile contaminants laterally to adjacent vertical wells operated in vacuum mode. In
general, air was injected at 25-50% of capacity.
System Shutdown
System operation continued from May 1994 through January 1995. In July 1994, the system was
shut down for a one-week period due to a carbon changeout from the granular activated carbon
vessels. In addition, the system was shut down from January 18 until March 16, 1995 to assess
rebound of TCE, PCE, and 1,2-DCE in soil vapor monitoring wells. The system was operated
again from March through September 1995. System shutdown took place in September 1995,
and confirmatory soil borings were collected at that time.
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I TREATMENT SYSTEM DESCRIPTION (CONT.)
Operating Parameters Affecting Treatment Cost or Performance
The major operating parameters affecting cost or performance for this technology and the values
measured for each are shown in Table 4.
Table 4. Operating Parameters [12]
J Parameter „ _ 5 v
Air Flow Rate
Operating Pressure/Vacuum
f . * "• Value**
l,400scfm
8 inches Hg
Measurement Method
N/A
N/A
N/A - Measurement method not reported for this parameter because resulting value not expected to vary
among measurement procedures.
Timeline
A timeline for this application is shown in Table 5.
Table 5. Timeline [4, 5,12]
/*,„ ^L. A \
Start Date* ~
August 1987
March 1993
January 1994
April 1994
May 1994
January 18, 1995
March 1995
September 1995
August 1995
-?} En^Bate *'
-
-
April 1994
-
January 1995
March 16, 1995
September 1995
-
September 1995
^ * 7 ~" s .
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 13 of 28 •
i TREATMENT SYSTEM PERFORMANCE I
Cleanup Goals/Standards
The ROD for the Burn Pits Operable Unit identified the following soil cleanup standards for the
SVE application [1]:
• trichloroethene (TCE) - 0.005 mg/kg;
• tetrachloroethene (PCE) - 0.005 mg/kg; and
• 1,2-dichloroethene (1,2-DCE) - 0.005 mg/kg.
In addition, the following soil vapor goals (referred to as "initial soil vapor target goals") were
calculated by the basewide contractor to assess remediation progress [4]:
TCE-1.88^g/L;
PCE-3.14Aig/L;and
1,2-DCE-8.11/ug/L.
OHM stated the following as an interim requirement for wellhead equilibrium vapor
concentrations [6]:
* TCE - 1.7 mg/kg;
• PCE-1.7 mg/kg; and
• 1,2-DCE - 0.7 nig/kg.
OHM reported that the following air emission rate limits were identified for this application [12]:
• TCE - 0.0043 Ibs/hr (0.103 Ibs/day, assuming 24 hrs/day operation);
• PCE - 0.003 Ibs/hr (0.072 Ibs/day, assuming 24 hrs/day operation); and
• 1,2-DCE - 0.003 Ibs/hr (0.072 Ibs/day, assuming 24 hrs/day operation).
Additional Information on Goals
The soil cleanup goals were developed based on a risk assessment which considered the
following as the primary potential future risks to public health:
• Migration of contamination from soil to groundwater; and
• Public exposure to contamination via inhalation of dust, direct contact with, or ingestion
of, contaminated soil. [1]
According to the vendor, the air emission rate limits were developed based on a risk-based
analysis with a target cancer risk criterion of 1 x 10-6, with a "100 fold" margin of safety. [12]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sacramento Army Depot Superfund Site, Bum Pits Operable Unit, Page 14 of 28
TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data
Treatment performance data for the SVE application at the Burn Pits Operable Unit consists of
confirmation soil borings, soil vapor sampling (from the SEAMIST wells), mass extraction data,
and extraction well vapor concentrations.
Confirmatory Soil Borings [6, 10, 11, 12]
In September 1995, OHM collected 21 confirmation soil borings from 8 locations near the burn
pits, at depths ranging from 20 to 80 feet bgs. The borings were analyzed for TCE, PCE, trans-
1,2-DCE, and cis-l,2-DCE. Figure 5 shows the location of the confirmation borings relative to
the burn pits at SAAD, and Table 6 shows the results on a dry-weight basis for the four
constituents measured in the 21 confirmation soil borings. In addition, Table 6 shows the boring
number, depth, and sample identification number. As shown on Table 6, OHM calculated the
"statistical mean" (average) result for each constituent in the 21 confirmation soil borings. For
analytical results reported as less than the detection limit, OHM assumed a value of one-half the
reported detection limit for computing the average value (e.g., for a sample reported as less than
0.002 mg/kg, OHM assumed an actual value of 0.001 mg/kg). Also as shown in Table 6, OHM
calculated the average both with and without the quality control (QC) sample results. With the
QC results, the average for the four constituents ranged from 0.0013 to 0.0021 mg/kg, and
without the QC results the average ranged from 0.001 to 0.0016 mg/kg.
N
•A
Qsvwa
LEGEHSl
Dual-Vacuum Extraction Wrt (80 fl)
_n- (£ Slngl*.V>cuumEx!i«ctlorMMI(25ft)
Confirmation Boring (80ft)
Confirmation Boring (20ft)
• Soil Boring
B BaiailM Soil Boring (20 ft)
(KWntMdtr19K>-imi)
Figure 5. Location of Confirmation Soil Borings [12]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
XechnolosLlnnoaation Office.
57
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 15 of 28 •
Table 6. Dry Weight Analytical Results for Confirmation Soil
Boring Samples [12]
Boring
CB1
CB1
CB1
CB1
CB2
CB2
CB4
CB4
CB4
CB4
CBS
CBS
CBS
CBS
CB6
CB7
CBS
CBS
CBS
CBS
CBS
CBS
CBS
CBS
Depth (ft.)
20
39
60
78
20
20
20
20
40
59
78
20
41
60
78
78
20
20
20
39
59
59
78
78
Sample-ID No.
SAADCB1-20
SAADCB1-39
SAADCB1-60
SAADCB1-78
SAADCB2-20
SAADCB2-
20QC
SAADCB3-20
SAADCB4-20
SAADCB4-40
SAADCB4-59
SAADCB4-78
SAADCB5-20
SAADCB5-41
SAADCB5-60
SAADCB5-78
SAADCB5-
78QC
SAADCB6-20
SAADCB7-20
SAADCB8-20
SAADCB8-39
SAADCB8-59
SAADCB8-B
SAADCB8-78
SAADCB8-
78QC
Statistical Mean* (with QC Results)
Statistical Mean* (without QC Results)
Analyte Concentration (mg/kg)
TCE
<0.002
<0.002
<0.002
<0.002
<0.002
<0.006
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
0.010
<0.007
<0.002
<0.002
<0.002
<0.002
<0.002
0.003
0.003
0.011
0.0021
0.0016
•--• PCE • „
<0.002
<0.002
<0.002
<0.002
<0.002
<0.006
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.007
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.008
0.0013
0.001
1.2 Trans-
DCE
<0.002
<0.002
<0.002
<0.002
<0.002
<0.006
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.007
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.008
0.0013
0.001
1,2 cis- *
DCE
<0.002
0.005
<0.002
<0.002
<0.002
<0.006
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.007
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.008
0.0015
0.0012
*Mean (average) values calculated assuming results reported as less than detection limit were present at one-half
detection limit.
U.S. ENVIRONMENTAL PROTECTION AGENCY
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Technology Innovation Office
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 16 of 28 •
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Soil Vapor Sampling [41
To assess the progress of the remediation,
soil vapor samples were collected from six
SEAMIST wells. As shown in Figure 3, the
six SEAMIST wells were located throughout
the soil vapor extraction wellfield. Five
SEAMIST wells contained 10 sample ports
each, and one well contained 9 ports. The
sample ports in each SEAMIST well were
vertically distributed in the primary
stratigraphic units determined from site
investigation borings and well logs. Figure
6 shows a SEAMIST well construction
detail, and Table 7 shows the sample port
depths for the six wells.
The SEAMIST well vapor samples were
collected in 1-liter Summa™ canisters and
analyzed for TCE, PCE, and 1,2-DCE using
a modified EPA Method TO-14. Table 8
shows the range of soil vapor concentrations
for TCE, PCE, and 1,2-DCE before and
during shutdown (on January 18, 1995 and
February 28, 1995) in the six SEAMIST
wells. In addition, Table 8 shows the range
Interior of
Uner Filled
with Fine Sand
Figure 6. Seamist Well Construction Detail
[4]
of baseline concentrations for TCE in soil vapor in April 1994, prior to SVE system startup.
Table 7. Sample Port Depths for SEAMIST Wells [4]
- -'
Well
ID
SM-1
SM-2
SM-3
SM-4
SM-5
SM-6
- " -' "Sample Port" "', , '•;, ^
1
2 s
3
1 '4
/
". 5
6
" 7t
8
9
* 10
, ' ~~ "' '-_ Depttf(feet) '„!""- \< ~
8
10
10
10
12
10
18
20
18
18
20
15
31
28
26
26
28
20
37
35
33
34
36
35
44
42
39
42
44
45
53
48
46
48
53
53
60
55
53
56
59
58
66
65
63
64
65
65
72
72
73
72
73
72
77
N/A
79
80
80
80
N/A - Not applicable; well SM-2 had only 9 sample ports.
U.S. ENVIRONMENTAL PROTECTION AGENCY
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page'17 of 28 •
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 8. Range of Soil Vapor Concentrations Before and During Shutdown [4]
Compound
Trichloroethene
(TCE)
Tctrachloroethene
(PCE)
1,2-DichIorocthcne
(1,2-DCE)
Initial Soil Vapor
Target Goal
Cug/L)
1.88
3.14
8.11
Baseline :
Concentrations
(April 1994)
C"g/L)
0.4-199.6
N/A
N/A
Before Shutdown
Concentrations
(January IS, 1995)
G"g/L>
ND - 12.9
ND
ND - 2.9
- During Shutdown
' Concentrations
(February 28, 1995)
C"g*L)
ND-7.6
ND
ND - 3.3
N/A - Data not available
ND - Not detected (detection limit not provided).
Extraction Well Vapor Concentrations [6,12]
Extraction well vapor concentrations were measured in February 1994 during drilling of wells at
depths of 20 to 25,45,55, 65, and 75 feet bgs. A metal probe containing well screen openings at
its tip was hydraulically thrust into the soil ahead of the augers. The probe was connected to
Teflon™ tubing which extended up to the surface. The Teflon™ tubing was purged of air prior
to collection of a vapor sample. After purging, the Teflon™ tubing was attached to a Tedlar bag
within a vacuum chamber. As the chamber was evacuated'by an air pump, the bag filled with
soil gas. To prevent cross-contamination, the equipment was cleaned and new Teflon tubing was
used to collect each sample.
Vapor analyses were conducted both at an on-site laboratory and by a third party laboratory. The
maximum concentrations of TCE, PCE, and 1,2-DCE measured during drilling of the shallow
and deep wells, reported by the off-site laboratory, are shown in Table 9. The highest
concentrations of TCE, PCE, and 1,2-DCE were generally found at approximately 50 to 60 feet
bgs and 70 to 80 feet bgs. In addition, Table 9 shows the interim results from July 1994 (system
operation began in May 1994) at the wellheads for TCE, PCE, and 1,2-DCE.
U.S. ENVIRONMENTAL PROTECTION AGENCY
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 18 of 28 •
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 9. Concentrations in Extraction Well Vapors [6, 12]
•" J f "\
°" ; ~" Wi
I ~ * S
_ * ™ * ~ -%-
.' Compound -
Trichloroethene (TCE)
Tetrachloroethene (PCE)
1,2-Dichloroethene (1,2-DCE)
A; ^ , - j
" 'JL -- r ""
Vendor Interim
Requirement (goal) -
^ Inig/kgK : •- "
1.7
1.7
0.7
" ' ' "^ * ^
Maximum Dnring Drilling (mg/kg)
^ » ^
ShallbwWen>
3.248
0.665
2.4
f, s^ " ^ -'
1 ^ - -,
; Deep WeU
10.37
3.422
4.1
4 , " ~
Interim Results at
_ Wellheads -:J«ly „
1994(mg/li)
0.41
0.20
0.58
Mass Extraction Data [6, 12]
The mass extraction (removal) rates of TCE, PCE, and 1,2-DCE over the first six months of
system operation are shown in Figure 7. The cumulative mass of TCE, PCE, and 1,2-DCE
removed over this six-month period is presented in Figure 8. Tables 10 and 11 show the data
used to prepare Figures 7 and 8, respectively, for the run times from 42 to 170 days, and for day
KEY
+ TCE
* 1.2DCE
. PCE
x TOTAL TARGET COMPOUNDS
140
160
180
RUN TIME,
days
346.
Figure 7. Mass Removal Rates of TCE, PCE, and 1,2-DCE [6]
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Technology Innovation Office
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Sacramento Array Depot Superfund Site, Burn Pits Operable Unit, Page 19 of 28 •
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
140T
, 120- -
|-100
O
1 80
CO
CO
60--
40--
O
20--
KEY
TOTAL TARGET COMPOUNDS
+ TCE
*1,2DCE
0 20 40 60 80 100 120 140 160 180
RUN TIME, days
Figure 8. Cumulative Mass Extracted of TCE, PCE, and 1,2-DCE [6]
Note that Tables 10 and 11 do not show the removals from the beginning of system operation
through the 42nd day of run time (these data were not provided by the vendor).
Air Emissions F121
Table 10 shows the ah* emissions from system operation at the outlet from the secondary carbon
unit. As shown hi Table 10, for the run times from 42 to 170 days, the actual air emissions
ranged from 0 to 0.51 Ibs/day, shown as a total for the three target compounds. Actual air
emissions were not provided by the vendor for the run time from 0 to 42 days.
U.S. ENVIRONMENTAL PROTECTION AGENCY
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Technology Innovation Office
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-Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 20 of 28 •
Table 10. Mass Removal Rates of TCE, PCE, and 1,2-DCE
! !
1
H, '.%!*
\ * '
t ( t *i !
Cumulative l
RunTime*
k \ < Ways)- f
Air Emission
Limit
42.05
48.58
54.56
63.5
69.5
78.5
82.5
91.53
99.54
109.87
140.52
147.63
172.58
346.60
, x' i > , ' "fCE^ ' ; v t ,''
*" Inlet io
"Ertoary '
„ ,uCarbon s
^abstoay)
-
0.34
0.29
0.1
0.15
0
0.05
0
0
0
0
0
0
0.15
0
t>.
Outlet from
' ^ i i ^
„ Secondary
" Carbon ,
' jibs/day) K
0.103
0
0
0
0
0
0
0
0
0
0
0.09
0
0.1
0
Amount
ll V
Removed ^
by Carbon
\ {fts/day).,
-
0.34
0.29
0.1
0.15
0
0.05
0
0
0
0
(0.09)**
0
0.05
0
' s>-. , ' *. npcte . '* "• ,'"' u,
Wet to !
^friinary',
v Carbon ,
Wdayji, Uf
-
0.19
0
0.05
0
0
0.12
0
0
0
0.11
0
0
0.21
0
Outlet from
Secondary *'
^ * Carb'ou * • <
raHday)^
0.072
0
0
0
0
0
0
0
0
0
0
0
0
0.06
0
1 ' ',8 > "'i
, , Amount
Removed *
%-€arbott\
'"abs^a^^
-
0.19
0
0.05
0
0
0.12
0
0
0
0.11
0
0
0.15
0
12]
, 4'-,,ri '- 'il^B>CE* '"* "', •"•,,
\inietto1 s
Primary
,, Carbon
(Ibs/day)
-
0.16
0.06
0.07
0
0.08
0
0
0
0
0
0
0
0
0
SOutletlrom
l< Secondary
Carbon |
^{IbsftiayK
0.072
0.18
0.24
0.3
0.42
0.51
0.23
0.29
0
0.08
0.08
0
0
0
0
Amount
. Removed
by Carbon '
(Ibs/day)
-
(0.02)**
(0.18)**
(0.23)**
(0.42)**
(0.43)**
(0.23)**
(0.29)**
0
(0.08)**
(0.08)**
0
0
0
0
*Cumulative run time as shown for inlet to primary carbon unit
**Values shown in parentheses () indicate that the quantity in the outlet from the secondary carbon was greater than the quantity in the inlet to the primary carbon.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 21 of 28 •
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Table 11. Cumulative Mass Extracted of TCE, PCE, and 1,2-DCE* [12]
Cumulative Run
Time (days)
42.05
48.58
54.56
63.5
69.5
78.5
82.5
91.53
99.54
109.87
140.52
147.63
172.58
346.60
TCE
Obs)
62.97
64.86
66.01
67.09
67.55
67.77
67.87
67.87
67.87
67.87
67.87
67.87
69.7
73.86
PCE
(Ibs)
22.84
23.45
23.6
28.8
23.81
24.35
24.6
24.6
24.6
25.17
26.88
26.88
29.5
35.12
DCE
(Ibs)
26.62
27.25
27.63
27.91
28.15
28.52
28.52
28.52
28.52
28.52
28.52
28.52
28.52
28.61
Total Target
Compounds (Ibs)
112.43
115.56
117.24
123.8
119.51
120.64
120.99
120.99
120.99
121.56
123.27
123.27
127.72
137.6
*Data reported for inlet to primary carbon unit; cumulative run time for blower no. 7681.
Performance Data Assessment _^
The FIVE system achieved the specified soil cleanup goals for all three target constituents - TCE,
PCE, and 1,2-DCE. As shown on Table 6, the average value for the 21 confirmation soil borings
was less than the cleanup goals of 0.005 mg/kg for TCE, PCE, and 1,2-DCE. Table 6 shows that
the average TCE value was 0.0021 mg/kg, PCE was 0.0013 mg/kg, and 1,2-DCE was 0.0028.
(These values include the QC samples; the average results without the QC samples are slightly
lower.) As shown on Table 6, OHM reported the 1,2-DCE values separately for the trans and cis
isomers of this constituent; however, these results were added together to compare with the
cleanup standard. Of the 96 analytical values shown on Table 6, only two (TCE in SAADCB5-
78 at 0.010 mg/kg and in SAADCB8-78QC at 0.011 mg/kg) were greater than the target cleanup
goal of 0.005 mg/kg. la addition, only 5 of the 96 values were reported as detected values; the
remainder were all reported as not-detects with a detection limit ranging from 0.002 to 0.008
mg/kg.
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 22 of 28 •
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment
There were a limited quantity of soil vapor data collected during this application, with samples
collected at "baseline" (April 1994), before shutdown (January 1995), and during shutdown
(February 1995). Based on these limited data, it appears that the TCE soil vapor concentration
was greater than the soil vapor target goal, PCE (at ND), and 1,2-DCE (at a maximum of
3.3 ug/L) appear to have met their soil vapor target goals.
In addition, there were a limited quantity of extraction well vapor data collected during this
application, with samples collected during drilling and in July 1994. The data in Table 9 show
that the interim results at the wellheads for July 1994 met the vendor's interim requirement
(goal) for all three target contaminants.
The vendor indicated that the FIVE technology is intended to produce relatively larger
subsurface pressure gradients and higher flow rates of extracted vapors than would be achieved
solely with using vapor extraction technology. The vendor stated that this process "enhanced
subsurface volatilization and shortened the period of remediation" [6], however, no data were
provided to support this statement. For example, the vendor did not estimate how much
additional time would have been required to reach the cleanup goals solely using vapor
extraction technology.
Figures 8 and 9 show rapid extraction of target VOCs during the first 40 days of system
operation, and more gradual extraction over the next 140 days. For example, the mass extraction
rates decreased by more than 75% from an average of 4 pounds per day (Ibs/day) over the first 20
days of system run time to less than 1 Ib/day after 40 days of system run time. As shown in
Table 11, the cumulative quantity of contaminant extracted from the subsurface over 347 days of
run time was approximately 138 Ibs, consisting of 74 Ibs of TCE, 35 Ibs of PCE, and 29 Ibs of
1,2-DCE. More than 80% of the total mass was extracted during the first 42 days of run time,
and almost 93% of the total mass was extracted during the first 173 days. More than half of the
total mass extracted was TCE, and the remainder consisted of nearly equal quantities of PCE and
1,2-DCE.
The 138 Ibs of target VOCs extracted during system operation is approximately two times greater
than the originally estimated mass of TCE, PCE, and 1,2-DCE existing beneath the site. The
quantity of TCE extracted is more than three times greater than the original estimate. Possible
reasons identified by the treatment vendor include inaccuracies in the original estimate, and, for
1,2-DCE, a reductive dehalogenation mechanism that took place in situ.
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 23 of 28 •
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment (cont.)
The data in Table 10 show that air emissions (as measured at the outlet from secondary carbon)
from days 42 through 172 sometimes were greater than the limits described above. TCE and
PCE met their air emission limits, however, 1,2-DCE exceeded its air emission limit. For
example, on Day 42,1,2-DCE was emitted at a rate of 0.18 Ibs/day, which is greater than the
limit of 0.072 Ibs/day. 1,2-DCE emissions from run time 42 to 172 days ranged from 0.08 to
0.51 Ibs/day, exceeding the emissions limit on nine sampling dates.
The data in Table 10 also show that the carbon columns were not effective in removing 1,2-DCE
from the extracted air, in that more DCE was released from the carbon than was extracted from
the subsurface. Based on a sum of the daily inlet and outlet quantities from run times 42 to 172
days, the carbon showed an average TCE removal rate of 82%, and for PCE of 91%. Note that
because the carbon was not effective in removing 1,2-DCE, the calculation of the cumulative
amount removed by carbon for the three target contaminants is a negative number.
Performance Data Completeness
Analytical data are available for the following: 1) the concentrations of contaminants in the soil
prior to treatment; 2) the concentrations of contaminants in soil vapors and extraction well
vapors; 3) mass extraction rate and cumulative mass extraction data; 4) soil boring confirmation
samples measuring concentrations of contaminants in the soil after treatment; and 5) air
emissions from the carbon units.
Performance Data Quality
The treatment vendor reported that confirmation soil borings were analyzed using standard EPA
methods 8240, 8270, and 8080, and that three duplicate field samples were collected and
analyzed. The field duplicates confirmed that the target analytes were below detected values,
however the detection limits for the duplicates were 3 to 4 tunes greater than those for the
original samples. No additional information was provided on why the detection limits were
higher for the field duplicates. [12]
I TREATMENT SYSTEM COST
Procurement Process
OHM was awarded a contract by the USAGE, Sacramento District, for the design, construction,
and operation of an enhanced SVE system with pressurized injection. [5] According to the
vendor, the procurement was a "non-programmatic open governmental bidding process". [12]
No
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 24 of 28 •
I TREATMENT SYSTEM COST (CONT.)
Procurement Process (cont.)
information was provided on the number of bidders or the basis for selecting OHM as the
treatment vendor.
Kleinfelder provided support to the Army at SAAD under a basewide contract, and was tasked
by the USAGE, Sacramento District, with monthly sampling of monitoring wells during OHM's
operation, and other activities. [4]
Treatment System Cost [5,12] a
OHM reported a total cost of $865,873 for this application. In order to standardize reporting of
costs across projects, the costs were broken down according to the format for an interagency
Work Breakdown Structure (WBS). The WBS specifies 9 before-treatment cost elements, 5
after-treatment cost elements, and 12 cost elements that provide a detailed breakdown of costs
directly associated with treatment.
Following the WBS, the total cost reported by OHM was broken down in before-treatment costs,
shown in Table 12, and costs directly attributed to treatment activities, shown in Table 13. No
costs were incurred for after-treatment activities in this application. Tables 12 and 13 present the
cost elements exactly as they appear in the WBS. As shown in Table 12, approximately
$195,000 were expended in before-treatment costs for drilling, soil gas survey, confirmatory
boring, and chemical testing. Table 13 shows that approximately $670,500 were expended for
activities directly attributed to treatment, such as design, mobilization, construction, start-
up/testing/permitting, SVE operations and maintenance, disposal of carbon, and demobilization.
The $670,500 in costs directly attributed to treatment corresponds to $2.70 per cubic yard of soil
treated (247,900 cubic yards) and $4,858 per pound of target VOC removed (for the 138 pounds
of TCE, PCE, and 1,2-DCE removed,).
Table 12. Before-Treatment Costs [5]
' _ / Cost Element *~ .'-,/-
Monitoring, Sampling, Testing, and Analysis
- drilling/soil/gas survey: $161,497
- confirmatory borings (including chemical testing): $33,865
-- _- Cost{$)
195,362
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sacramento Army Depot Superfund Site, Bum Pits Operable Unit, Page 25 of 28 •
I TREATMENT SYSTEM COST (CONT.)
Treatment System Cost (cont.) [5, 12]
Table 13. Costs Directly Attributed to Treatment [5,12]
Cost Element
Mobilization/Setup
- design package: $44,486
- mobilization/construction: $159,877
Startup/Testing/Permits
Operation (short-term - up to 3 years)
Demobilization
Total
- Cost($) "'
204,363
26,764
418,812
20,572
670,511
Cost Data Quality
The costs described above represent actual costs for this treatment application as reported by
OHM. Limited information is available on the specific activities included within the cost
elements for monitoring, sampling, testing, and analysis, and mobilization/setup. No information
is available on the specific activities included within the other reported cost elements.
Vendor Input
OHM reported that costs for similar projects can be reduced by the following methods [12]:
• Remediation-based RI/FS studies should be conducted;
• Realistic cleanup goals should be established by the regulators; and
• Innovative- and contaminant-based treatment technologies for off-gas treatment should
be implemented.
US. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
68
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Sacramento Army Depot Superftmd Site, Burn Pits Operable Unit, Page 26 of 28 •
I OBSERVATIONS AND LESSONS LEARNED
Cost Observations and Lessons Learned
• The treatment vendor reported a total actual cost of $865,873 for this application. Of
this total, approximately $195,000 were expended in before-treatment costs for drilling,
soil gas survey, confirmatory boring, and chemical testing, and approximately $670,500
were expended for activities directly attributed to treatment, such as design,
mobilization, construction, start-up/testing/permitting, SVE operations and maintenance,
and demobilization.
• The $670,500 in costs directly attributed to treatment corresponds to $2.70 per cubic
yard of soil treated (247,900 cubic yards) and $4,858 per pound of target VOC removed
(138 pounds of TCE, PCE, and 1,2-DCE). These unit costs show that this application
treated a relatively large volume of soil contaminated with relatively small
concentrations of target VOCs.
Performance Observations and Lessons Learned ,
• The soil boring confirmation data show that the SVE system used at the Burn Pits
Operable Unit met the soil cleanup goals for VOCs within 14 months of system
operation.
• The system consisted of a patented fluid injection/vacuum extraction (FIVE) technology
designed to produce relatively larger subsurface pressure gradients and higher flow rates
of extracted vapors than would be achieved solely with using vacuum extraction
technology. The system had approximately 347 days of run time over the 14 month
operating period (81% run time). The vendor stated that this system "enhanced
subsurface volatilization and shortened the period of remediation."
• Soil concentrations were reduced from a maximum of 0.012 mg/kg (for TCE) to less than
the cleanup goals (e.g., less than 0.005 mg/kg). TCE was reduced to an average of
0.0021 mg/kg, PCE to 0.0013 mg/kg, and 1,2-DCE to 0.0027 mg/kg.
• Approximately 138 Ibs of the three target VOCs (TCE, PCE, and 1,2-DCE) were
extracted during 347 days of system run time. The VOC extraction rate decreased by
more than 75% from an average of 4 pounds per day (Ibs/day) over the first 20 days of
system run time to less than 1 Ib/day after 40 days of system run time.
• The 138 Ibs of VOCs extracted during this application is approximately two times
greater than the original estimate for mass of TCE, PCE, and 1,2-DCE existing beneath
the site. The quantity of TCE extracted is more than three times greater than the original
estimate. Possible reasons identified by the treatment vendor for 1,2-DCE included a
reductive dehalogenation mechanism that took place in situ.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
69
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Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 27 of 28 •
•• OBSERVATIONS AND LESSONS LEARNED (CONT.) I
Performance Observations and Lessons Learned (cont)
• Air emissions for TCE and PCE met their air emission limits, however, 1,2-DCE
exceeded its limit on nine sampling dates from run time days 42 through 172. According
to the vendor, these exceedances were not of concern because of the safety factor
included in the emission limits (see discussion on goals).
Other Observations and Lessons Learned
• As part of this remediation, the treatment vendor performed extensive investigations into
site geology, including a "facies analysis" to collect data concerning the sedimentary
structures and scales of heterogeneity in strata within the vadose zone. The results of the
facies analysis were used in the design of the SVE system, particularly in the location
and depths of the extraction wells.
• The extraction/injection wells included in the system design proved to be useful for
adjusting to site conditions. For example, it was very wet during mid-winter system
operation, and the vendor increased the injection rate and decreased the extraction rate to
minimize the amount of water that was extracted at that time.
•• REFERENCES
1. Superfund Record of Decision: Sacramento Army Depot Burn Pits Operable Unit. Sacramento,
California. February 26,1993.
2. Fact Sheet. Bum Pits - Record of Decision. Sacramento Army Depot. June 1993. Number 3.
3. Soil Venting System Startup Report. Remediation of Burn Pits Sacramento Army Depot,
Sacramento, California. OHM Remediation Services Corp. June 1994.
4. Rebound Sampling Summary Report, Seamist Monitoring Wells, South Post Bum Pits,
Sacramento Army Depot, Sacramento, California. Kleinfelder, Inc. May 16,1995.
5. Correspondence from Ashok Gopinath, Project Engineer, to Tim McLaughlin, Radian
Corporation, regarding Cost and Performance Data for the Soil Vapor Extraction System at the
Sacramento Army Depot (SAAD) Bum Pits Site. August 24,1995.
6. Proceedings of the Ninth National Outdoor Action Conference and Exposition, Aquifer
Remediation/Groundwater Monitoring/Geophysical Methods presented by the National Ground
Water Association. May 2-4,1995.
US. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
70
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I REFERENCES (CONT.)
Sacramento Army Depot Superfund Site, Burn Pits Operable Unit, Page 28 of 28 •
7. Telephone Call Record from Tim McLaughlin, to Pamela Wee, regarding Information on SAAD
Burn Pits OU. May 9, 1995.
8. Telephone Call Record from Tim McLaughlin, to Dan Oburn, regarding Information on SAAD
Burn Pits OU. May 10,1995.
9. Telephone Call Record from Tim McLaughlin, to Pamela Wee, regarding Information on SAAD
Burn Pits OU. May 18,1995.
10. Conversation from Tim McLaughlin, Radian Corporation, to Ashok Gopinath, OHM, regarding
Followup on Sacramento Army Depot Burn Pits Superfund Site. October 9,1995.
11. Correspondence from Ashok Gopinath, Project Engineer, to Tim McLaughlin, Radian
Corporation, regarding Cost and Performance Data for the Soil Vapor Extraction System at the
Sacramento Army Depot (SAAD) Burn Pits Site. November, 6, 1995.
12. Letter from A. Gopinath, OHM Remediation Services Corp., to L. Fiedler, U.S. EPA,
"Remediation Case Study Report, Soil Vapor Extraction at the Burn Pits Operable Unit,
Sacramento Army Depot, Sacramento, California, November 1995," March 26,1996.
Analysis Preparation
This case study was prepared for the U.S. Environmental Protection Agency's Office of Solid
Waste and Emergency Response, Technology Innovation Office. Assistance was provided by
Radian International LLC under EPA Contract No. 68-W3-0001 and U.S. Army Corps of
Engineers Contract No. DACA45-96-D-0016.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Soil Vapor Extraction at the Sand Creek Industrial Superfund
Site, Operable Unit No. 1, Commerce City, Colorado
73
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Case Study Abstract
Soil Vapor Extraction at the Sand Creek Industrial Superfund Site,
Operable Unit No. 1, Commerce City, Colorado
Site Name:
Sand Creek Industrial Superfund
Site, Operable Unit No. 1
Location:
Commerce City, Colorado
Contaminants:
Volatiles - Halogenated: chloroform,
methylene chloride, tetrachloroethene (PCE),
and trichloroethene (TCE); Volatiles -
Nonhalogenated: TPH
- Maximum soil concentrations: chloroform
- 0.820 mg/kg; methylene chloride - 5.8
mg/kg; TCE - 0.087 mg/kg; and PCE -
9.34 mg/kg
Period of Operation:
September 24, 1993 - April 27,
1994
Cleanup Type:
Full-scale cleanup
Vendor:
Christopher Strzempka
Project Technical Mgr. for OU-1
OHM Remediation Services Corp.
16406 U.S. Route 224 East
Findlay, OH 45840
(800) 537-9540
SIC Code:
2879 (Pesticides and Agricultural
Chemicals, NEC)
2911 (Petroleum Refining)
Technology:
Soil Vapor Extraction
- System was OHM's patented Fluid
Injection-Vacuum Extraction (FIVE)
technology
- Included 31 vertical wells and 1 horizontal
well, and catalytic oxidizer
- Welk screened 3-32.5 ft below ground
surface (bgs)
- Some wells operated as injection wells and
others as extraction wells
Cleanup Authority:
CERCLA
- Action Memorandum Date
9/29/89
- Federal Lead/Fund Financed
Point of Contact:
Erna Waterman, 8 EPR-SR
USEPA Region Vm
999 18th Street, Suite 500
Denver, CO 80202-2466
(303) 312-6762
Waste Source:
Manufacturing Process
Purpose/Significance of
Application:
Full-scale application combining
fluid injection and vacuum
extraction wells to treat VOC-
contaminatcd soil.
Type/Quantity of Media Treated:
Soil
- Estimates of quantity treated ranged from 31,440 - 52,920 yd3
- Sandy loams, loamy sands
- Silt and clay - 19.99-24.71%
- LNAPL plume also identified at site
Regulatory Requirements/Cleanup Goals:
- Soil cleanup goals specified for 4 VOCs as follows: chloroform - 0.165 mg/kg; methylene chloride - 0.075 mg/kg;
TCE - 0.285 mg/kg; and PCE - 1.095 mg/kg
Results:
- Soil cleanup goals met within 6 months of system operation
- Maximum concentrations in treated soil were: chloroform - 0.0099 mg/kg; methylene chloride - ND; TCE - 0.10
mg/kg; and PCE - 0.28 mg/kg
- Approximately 3,250 Ibs of chloroform, methylene chloride, TCE, and PCE extracted (primarily PCE)
- Approximately 176,500 Ibs of total VOCs extracted
74
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Case Study Abstract
Soil Vapor Extraction at the Sand Creek Industrial Superfund Site,
Operable Unit No. 1, Commerce City, Colorado (Continued)
Cost Factors:
- Approximately $2,140,000 were expended for this application, including $81,231 for before-treatment activities, and
$2,058,564 for activities directly attributed to treatment
- The unit cost for activities directly attributed to treatment was $39-65/yd3 of soil treated, and $11.70/lb of VOC
removed
- EPA's decision to revise air emissions control equipment from activated carbon with off-site regeneration to catalytic
oxidation resulted in a significant cost savings to the government
Description:
The Sand Creek O.U. 1 site was the location of pesticide manufacturing companies in the 1960s and 1970s, and prior to
that, by a petroleum refinery. The pesticide manufacturing companies had two fires in the period from 1968-1977, and
were reported to have unsatisfactory waste management practices. Remedial investigations conducted from 1984 to 1988
showed three subareas of soil contamination at Sand Creek O.U. 1 with the following maximum soil concentrations of
halogenated VOCs: chloroform - 0.820 mg/kg, methylene chloride - 5.8 mg/kg, TCE - 0.087 mg/kg, and PCE - 9.34
mg/kg. Based on these concentrations, EPA estimated the total mass of the four target contaminants in the operable
unit as 684 pounds.
A Record of Decision (ROD) addressing Sand Creek O.U. 1 was signed in September 1989 and an Explanation of
Significant Differences (BSD) modifying the 1989 ROD was issued in September 1993. OHM's patented fluid
injection/vapor extraction (FIVE) system was used to remediate O.U. 1. In the FIVE technology, pressurized air is
injected into vadose zone soils to produce relatively larger subsurface pressure gradients and higher flow rates of
extracted vapors than would be achieved solely with using vapor extraction technology. The FIVE system used at
O.U. 1 consisted of 32 extraction/injection wells (31 vertical, 1 horizontal), three positive displacement blowers (for
extraction), one liquid/vapor separator, one catalytic oxidizer, and two blowers (for injection). The wells were screened
up to 32.5 feet below ground surface.
Confirmatory soil borings showed that the concentrations for all four target contaminants were less than the cleanup
standards set in the ROD. The maximum concentration of target contaminants measured in the confirmation soil
borings was: chloroform - 0.0099 mg/kg, methylene chloride - not detected, TCE - 0.10 mg/kg, and PCE - 0.28 mg/kg.
Approximately 176,500 pounds of total VOCs were extracted during this application, including 3,250 pounds of the four
target contaminants. The mass of target compounds removed was almost 5 times greater than the original estimate.
According to the RPM, possible reasons for this discrepancy include VOC losses during pre-remediation sampling and
analysis, which can cause the results to be biased low; and results not representative of the zone of influence of the SVE
wells.
75
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——^—— Sand Creek Industrial Superfund Site, O.U. 1, Page i of 31
I COST AND PERFORMANCE REPORT I
•• EXECUTIVE SUMMARY
This report presents cost and performance data for a soil vapor extraction (SVE) system at the Sand
Creek Superfund site, Operable Unit (O.U.) 1, in Commerce City, Colorado. The SVE system was used
at the Sand Creek O.U. 1 site to treat soil contaminated with halogenated volatile organic compounds
(VOCs), specifically chloroform, methylene chloride, trichloroethene (TCE), and tetrachloroethene
(PCE), and nonhalogenated VOCs, including mixed petroleum hydrocarbons.
The Sand Creek O.U. 1 site was the location of pesticide manufacturing companies in the 1960s and
1970s, and prior to that, by a petroleum refinery. The pesticide manufacturing companies had two fires
in the period from 1968-1977, and were reported to have unsatisfactory waste management practices.
Remedial investigations conducted from 1984 to 1988 showed three subareas of soil contamination at
Sand Creek O.U. 1 (referred to as Subareas 1,2, and 3), with the following maximum soil concentrations
of halogenated VOCs: chloroform - 0.820 mg/kg, methylene chloride - 5.8 mg/kg, TCE - 0.087 mg/kg,
and PCE - 9.34 mg/kg. Based on these concentrations, EPA estimated the total mass of the four target
contaminants in the operable unit as 684 pounds. No information was provided in the available
references on the concentrations or mass of nonhalogenated VOCs in the three subareas.
A Record of Decision (ROD) addressing Sand Creek O.U. 1 was signed in September 1989 and an
Explanation of Significant Differences (BSD) modifying the 1989 ROD was issued in September 1993.
The modified ROD specified soil cleanup standards for the four target VOCs as follows: chloroform -
0.165 mg/kg, methylene chloride - 0.075 mg/kg, TCE - 0.285 mg/kg, and PCE - 1.095 mg/kg. No soil
cleanup standards were identified for the nonhalogenated VOCs.
The SVE system used in this application was a patented fluid injection/vapor extraction (FIVE) system.
In the FIVE technology, pressurized air is injected into vadose zone soils to produce relatively larger
subsurface pressure gradients and higher flow rates of extracted vapors than would be achieved solely
with using vapor extraction technology. The FIVE system used at Sand Creek O.U. 1 consisted of 32
extraction/injection wells (31 vertical, 1 horizontal), three positive displacement blowers (for extraction),
one liquid/vapor separator, one catalytic oxidizer, and two blowers (for injection). The wells were
screened up to 32.5 feet below ground surface.
The FIVE system was operated from September to December 1993, and again from January to April
1994, for a total of approximately six months of run time. Confirmatory soil borings collected in April
1994 showed that the concentrations for all four target contaminants .were less than the cleanup standards
set in the ROD. The maximum concentration of target contaminants measured in the confirmation soil
borings was: chloroform - 0.0099 mg/kg, methylene chloride - not detected, TCE - 0.10 mg/kg, and PCE -
0.28 mg/kg. Approximately 176,500 pounds of total VOCs were extracted during this application,
including 3,250 pounds of the four target contaminants. The 3,250 pound value was roughly
4.75 times greater than the original estimated mass of target contaminants (685 pounds). An air
emissions operating permit was not obtained for this application, however, air emissions were regulated
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
76
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Sand Creek Industrial Superfund Site, O.U. 1, Page ii of 31 •
| EXECUTIVE SUMMARY (CONT.)
U
under an Air Pollution Emission Notice issued by the Colorado Department of Health. Approximately
6,200 pounds of total VOCs were released to the atmosphere through stack emissions.
The total actual costs for this application were approximately $2,140,000. Of this total, about $82,000
were expended in before-treatment costs, such as for mobilization and preparatory work, confirmatory
sampling, and QA/QC laboratory analyses, and $2,058,000 were expended for activities directly
attributed to treatment, such as subcontractor costs, project management/administrative, SVE remedial
work, and cost of ownership. The costs directly attributed to treatment correspond to $39-65 per cubic
yard of soil treated (based on a range of soil quantity treated estimates of 31,440 to 52,920 cubic yards,
as provided by the vendor) and $11.70 per pound of VOC removed (based on 176,500 pounds).
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
77
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Sand Creek Industrial Superfund Site, O.U. 1, Page 1 of 31
SITE INFORMATION
Identifying Information;
Sand Creek Industrial Superfund site
Operable Unit No. 1
Commerce City, Colorado
CERCLIS # COD980717953
Action Memorandum Date: September 29,1989
Treatment Application;
TVpe of Action: Remedial
Treatability Study Associated with Application? Remedial
(see discussion under remedy selection)
EPA SITE Program Test Associated with Application? Remedial
Period of Operation: September 24,1993 to April 27,1994
Quantity of Material Treated During Application: There are varying estimates of the
quantity of soil treated during this application. These differences are attributed to the different
methods used to estimate soil volume for an in-situ application. The following estimates are
based on input from the vendor and have been reviewed by the RPM.
The treatment vendor (OHM) provided estimates for quantity of material treated based on (1) the
mean (average) groundwater depth and (2) the mean smear zone screen length, as shown below
for the three SVE system areas. (Smear zone is the area immediately above the groundwater
table, which, in this application, was the area from the top of the well screens to the water table,
and which was contaminated by hydrocarbons.) The vendor identified the areal extent of the
three SVE areas based on information in their solicitation and used average groundwater depth
and smear zone lengths to calculate soil quantity treated. [14]
Treatment Vendor Estimate of Soil Quantity Treated-Mean Depth to Groundwater [14]
SVE Area
1
2
3
Area (ft2)
29,300
30,872
7,238
Mean (Average)
Groundwater
Depth (ft)
12.4
27.2
31.2
Volume (ft3)
363,320
839,718
225,826
Total (based on mean groundwater depth)
Volume (yd3)
13,456
31,100
8,364
52,920
US. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
78
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Sand Creek Industrial Superfund Site, O.U. 1, Page 2 of 31
| SITE INFORMATION (Conk)
Treatment Application (conk):
Treatment Vendor Estimate of Soil Quantity Treated-Mean Smear Zone Screen Length [14,16]
q. >- »
w; -
x . *-j~ _
'"SVEArea ^
1
2
3
•B^-I ^ &
-' • -S * ;, *
•* i , - - •
/ jiArea(ft*)*'""
29,300
30,872
7,238
^s f
Mean Smear ^
"" Z&ne Screen ?
^ Length (ft) -""^
8.1
17.7
9
- f x _£—•
' X* " "~* X-
,_ Voliiinejft3) -
237,330
546,434
65,142
Total (based on mean smear zone)
.*- ^ v
yV s
r Volume (yd!)
8,790
20,238
2,412
31,440
According to the vendor, the estimate based on groundwater depth (52,920 yds3) assumes that all
soil hi the three SVE areas was contaminated, including the clean backfill in Area 2, while the
estimate based on smear zone (31,440 yds3) is a "conservatively low estimate". [14]
Background
Historical Activity that Contributed to Contamination at the Site: Pesticide Manufacturing,
Petroleum Refinery
Corresponding SIC Code: 2879 (Pesticides and Agricultural Chemicals, NEC),
2911 (Petroleum Refining)
Waste Management Practice that Contributed to Contamination: Manufacturing Process
Site History: The Sand Creek Industrial Superfund site (Sand Creek) covers approximately 550
acres and is located in Commerce City, Adams County, Colorado, as shown hi Figure 1. O.U. 1,
which covers approximately 13 acres of the Sand Creek site, was used by Times Chemical for
pesticide manufacturing and petroleum refining from 1960 to 1968. Prior to Times Chemical,
the land was used by the Oriental Refinery; no additional information is provided in the available
references on Oriental Refinery's operations. Around 1968, Times Chemical changed its name to
Colorado International Company (CIC). In 1968, a fire destroyed three buildings at the CIC
facility. An inspection of CIC by Tri-County District Health Department personnel in June 1974
indicated unsatisfactory waste management practices and unsatisfactory worker safety
conditions. [1,2,14, 15]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
79
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Sand Creek Industrial Superfund Site, O.U. 1, Page 3 of 31
[ SITE INFORMATION (CONT.)
Background (cont.)
In March 1976, the Colorado
Department of Health (CDH)
conducted a field inspection at CIC.
The inspectors observed 55-gallon
drums containing pesticides, including
parathion, stored in various locations at
the CIC facility. In addition, they
observed washwater, storm drainage,
and boiler feed water draining into a
common surface drainage that flowed
off property towards Sand Creek. A
second fire occurred at CIC in
December 1977, releasing parathion
fumes over northeast Denver. The state
of Colorado issued an Emergency
Cease and Desist Order in 1978 against
CIC to clean up the property and
adjacent areas contaminated by the fire.
CIC declared bankruptcy and re-
opened the operations as Colorado
Sand Creek Industrial
Superfund Site
Commerce City, Colorado
• Denver
Figure 1. Site Location
Organic Chemical Company (COC). COC operations were essentially the same as CIC
operations. [1]
Soil sampling at COC in early 1978 revealed elevated levels of halogenated organic compounds,
such as organophosphate pesticides and thermally-altered pesticides, and volatile organic
compounds (VOCs). In 1980, COC was cited for unsafe drum storage and improper storage
areas. In 1982, a consent agreement and final order were issued for RCRA violations. In March
1983, EPA deferred to the Department of Justice the matter of COC's RCRA violations and
violation of the consent agreement. In June 1983, a spill of the herbicide 2,4-dichlorophenoxy
acetic acid (2,4-D) resulted in an additional compliance order to clean up the spill and to comply
with previous orders. EPA issued a CERCLA 106 order in March 1984 for cleanup of the site.
Between April and September 1984, COC removed drummed wastes, product, and contaminated
soil from the site and fenced the site. [1]
Initial remedial actions at the site, which were conducted primarily in 1992, involved excavation
and incineration of contaminated soils, tank wastes, and pesticides. Approximately 40,000
pounds of material, consisting of several drums of toxaphene and pentachlorophenol and soil
contaminated with 2,4-D, were excavated and incinerated off site. Four buildings and four
railcars were demolished, and several storage tanks and other debris were removed from the site.
[2]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
80
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I SITE INFORMATION (CONT.)
Background (cont.)
Sand Creek Industrial Superfund Site, O.U. 1, Page 4 of 31 •
1
Regulatory Context: In September 1989, EPA issued a Record of Decision (ROD) for O.U. 1 at
the Sand Creek site. O.U. 1 addressed contaminated soils, buildings, and tanks at the COC
facility. The ROD required excavation and off-site incineration for highly contaminated soils
(greater than or equal to 1,000 mg/kg of halogenated organic compounds); soil vapor extraction
(SVE) for soil contaminated with volatile organic compounds (VOCs); and demolition and
treatment of contaminated buildings and tanks in accordance with the RCRA Land Disposal
Restrictions. In addition, the ROD required groundwater monitoring at the site for 30 years, and
performance of a public health evaluation once every five years following remediation. [1]
In September 1993, EPA issued an Explanation of Significant Differences (BSD) to modify the
1989 ROD for O.U. 1. The BSD modified the ROD by limiting the areal extent for operation of
soil vapor extraction technology, and by identifying additional costs for disposal of tanks from
the facility. [2]
In July 1994, EPA issued a ROD for Operable Unit No. 4 (O.U. 4) at the Sand Creek site. O.U. 4
involved remediation of a light non-aqueous phase liquid (LNAPL) plume at the site using a
combination SVE and dual vapor extraction (DVB) process (SVE/DVE). This treatment was
selected because the SVE system was already in place at the site. [12] The application of O.U. 4
is not discussed further in this report.
Remedy Selection: Soil vapor extraction was selected as the remedy for treatment of VOC-
contaminated soil in O.U. 1. According to the treatment vendor, the generally permeable nature
of the soil matrix indicated that the volatile fractions at Sand Creek, containing the more toxic
compounds, could be readily removed with SVE. [14] In 1990, EPA conducted a treatability
study to determine if the technology could adequately extract VOCs from O.U. 1 soils and to
determine the radius of influence for SVE wells at the site. The study showed that SVE was a
feasible remedial technology for the site and that a radius of influence of 60 feet could be
achieved at the site. [2,4]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superfund Site, O.U. 1, Page 5 of 31
I SITE INFORMATION (CONT.)
Site Logistics/Contacts
Site Management: Federal Lead/Fund Financed
Oversight: EPA
Remedial Project Manager:
Ms. Ema Waterman, 8 EPR-SR
U.S. Environmental Protection Agency
Region VIE
999 18th Street, Suite 500
Denver, Colorado 80202-2466
(303) 312-6762
(303) 312-6897 (fax)
ARCs Contractor:
John Chinnock
URS Consultants, Inc.
1099 18* Street, Suite 700
Denver, Colorado 80202-1907
(303) 296-9700
Remedial Design/Construction/Operation Subcontractor (Treatment Vendor):
Christopher Strzempka
Project Technical Manager for OU-1
OEM Remediation Services Corp.
16406 U.S. Route 224 East
Findlay, OH 45840
(800) 537-9540
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Sand Creek Industrial Superfund Site, O.U. 1, Page 6 of 31
I MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the Treatment System: Soil (in situ)
Contaminant Characterization
Primary Contaminant Groups: Volatiles - Halogenated: chloroform, methylene chloride,
tetrachloroethene, and trichloroethene; Volatiles - Nonhalogenated: TPH.
EPA conducted a Remedial Investigation (RI) at the site from 1984 to 1988. [3] Soils identified
as contaminated with pesticides (e.g., 2,4-D) were excavated and hauled off site for incineration.
Additional soil contamination at the site was identified by the vendor as consisting of mixed
petroleum and halogenated hydrocarbons, with some of the hydrocarbons classified as
semivolatile or non-volatile, including hydrocarbons of aromatic range and heavier hydrocarbons
toC-24. [11,14]
Three subareas of contaminated soil were identified during the RI, labelled Subareas 1, 2, and 3.
The maximum concentrations of VOCs in the soil identified by the RI are shown in Table 1.
Based on these data, the prime contractor estimated the total mass of chloroform, methylene
chloride, TCE, and PCE in the soil as 684 pounds. [4]
Table 1. Maximum Concentrations of Halogenated VOCs in Soil as Identified byRI [2]
-" ' ~ v- T Contaminant ,.
Chloroform
Methylene Chloride
Trichloroethene (TCE)
Tetrachloroethene (PCE)
,:, Maximum Concentration
(mg/kg)
0.820
5.8
0.087
9.34
In addition to the VOC contamination in the soil, a light non-aqueous phase liquid (LNAPL)
plume was identified floating on the groundwater at the COC facility. LNAPL plume thickness
was measured at the COC facility in October 1990, April 1991, November 1991, and September
1992. Table 2 shows the LNAPL Plume Thickness in five wells at the COC facility at those
times. As shown in Table 2, LNAPL thickness ranged from 1.69 to 4.72 feet in the five wells
and averaged from 2.29 to 3.69 feet over the 2-year sampling period. [5]
Figure 2 shows the relative locations of the three contaminated soil areas and LNAPL plume at
the Sand Creek site.
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Sand Creek Industrial Superfimd Site, O.U. 1, Page 7 of 31
I MATRIX DESCRIPTION (CONT.) |
Contaminant Characterization (cont)
Table 2. LNAPL Plume Thickness [5]
Well
URS-3
URS-4
URS-5
URS-6
URS-14
Average
Measured LNAPL Thickness (ft)
10/90
4.31
3.10
3.95
3.18
2.07
3.32
04/91
2.25
2.43
2.26
2.43
2.07
2.29
UJ91
3.49
3.60
4.45
3.34
3.58
3.69
09/92
2.48
3.82
4.72
1.69
3.01
3.14
/Suban*
/ SVE-3
N
I
SCALE NOT AVAILABLE
LNAPL PLUME (Additional Detail on
LNAPL Plume not Available)
OPERABLE UNIT #1
BOUNDARY
Figure 2. Locations of Contaminated Soil Areas and LNAPL Plume [11]
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Sand Creek Industrial Superfund Site, O.U. 1, Page 8 of 31
MATRIX DESCRIPTION (CONT.) I
Matrix Characteristics Affecting Treatment Cost or Performance
The major matrix characteristics affecting cost or performance for this technology and the values
measured for each are shown in Table 3.
Table 3. Matrix Characteristics [3,4,12, 14]
~ 1 , Parameter ff
Soil Classification
Clay Content and/or Particle Size Distribution
Moisture Content
Air Permeability
Porosity
Total Organic Carbon
Nonaqueous Phase Liquids
'* ' t -yahie ,- ~"
Sandy loams, loamy sands
Larger than 1/4"
0.34 - 3.66%
Granules (10 mesh to
1/4") 3.98 - 8.35%
Medium to very coarse
sand (60 to 10 mesh)
35.48-40.38%
Very fine to fine sand
(200 to 60 mesh)
30.01 - 34.99%
Silt and clay (less than
200 mesh) 19.99-
24.71%
3.0-30.1%
Not measured*
Not measured**
Not measured***
LNAPL layer present
k
Measurement Method
USDA Soil Conservation
Service
U.S. Standard Sieves
Measured values in 13
observations during well
installation
N/A
N/A
Measured on site
*Although air permeability testing was not conducted, the vendor reported the following: (1) the soils were predominantly
sandy, and well screens of 5-ft lengths in the vadose zone were producing extraction flows in excess of 100 SCFM at
relatively low vacuums; (2) using a simple steady-state facial flow equation for compressible flow described by Johnson
et al (1990), air permeabilities in excess of 2 x 10"7 cm2 (20 darcies) could be expected; and (3) moisture content in
the capillary fringe and saturated zones was the chief impediment to flow.
**Porosity measurements were not made during the project. Some interbedded silts and clays were found at O.U. 1, but soils
were predominantly sandy with estimated air-filled porosity in the vadose zones of 30 percent. [14]
***TOC analyses of soils were not made. The bulk of the soils were predominantly sands and silts characterized normally by low
TOC. [14]
N/A - Measurement method not reported for this parameter because resulting value not expected to vary among measurement
procedures.
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Sand Creek Industrial Superfund Site, O.U. 1, Page 9 of 31 '
MATRIX DESCRIPTION (CONT.) I
Site Geology/Stratigraphy
The RI indicated that the site is underlain by alluvial deposits consisting of high-permeability
sands and gravels, interbedded with low-permeability clayey and silty layers. Two groundwater
units underlie the site, separated by a relatively impermeable layer 10 to 20 feet thick. The upper
deposit is up to 40 feet thick and is primarily unsaturated (i.e., contains little to no groundwater).
The lower deposit is up to 44 feet thick and generally exists under confined conditions. [1] A
simplified schematic of the alluvial groundwater system at the Sand Creek site is shown in
Figure 3.
Plezometric Levels
WEST
EAST
Land Surface
Bedrock
NOT TO SCALE
Figure 3. Simplified Schematic of Alluvial Groundwater System at the Sand Creek Site
[3]
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-^—————^^^—^^^^^— Sand Creek Industrial Superfund Site, O.U. 1, Page 10 of 31
| TREATMENT SYSTEM DESCRIPTION
Primary Treatment Technology Type: Soil Vapor Extraction
Supplemental Treatment Technology Type: Catalytic oxidization
Soil Vapor Extraction System Description and Operation
System Description [4, 8,10, 12, 14]
The soil vapor extraction system used at Sand Creek consisted of 31 vertical wells and 1
horizontal well, and was thermally-enhanced by fluid injection with vacuum extraction (referred
to as the FIVE system). The wells were grouped into three subareas at the site: SVE-1, SVE-2,
and SVE-3. Thirteen vertical wells and the horizontal well were located in SVE-1 (wells 101
through 113 and H12). SVE-2 contained 12 wells (wells 201 through 212) and SVE-3 contained
6 wells (wells 301 through 306). The location of these wells at the site is shown in Figure 4. As
shown on Figure 4, well H12 is a horizontal well, and all other wells are vertical. For several of
the wells in each subarea, operation of the wells was alternated between vacuum extraction and
air injection during the course of remediation.
In their bid for the project, the vendor stated that both horizontal and vertical wells would be
included in the system, with "preference" given to horizontal wells because the vendor believed
such wells would increase the radius of influence. However, only one horizontal well was
included in the SVE system at Sand Creek. During installation of the initial horizontal well at
Sand Creek, the vendor discovered buried concrete blocks and other construction debris in the
subsurface. This created problems of increased friction during installation of the prepackaged
well screens resulting in delays. Therefore, after installation of the one horizontal well, the
vendor decided to replace the remaining planned horizontal wells with multiple vertical wells.
NOTE: Scatonamfabta
Figure 4. SVE Well Pattern [8]
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Sand Creek Industrial Superfund Site, O.U. 1, Page 11 ,of 3t
I TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
The screened intervals and depths for the wells at Sand Creek are as follows [14]:
SVE System
1
2
3
Well No.
SVE-101
SVE- 102
SVE-103
SVE-104
SVE-105
SVE-106
SVE-107
SVE-108
SVE-109
SVE-110
SVE-111
SVE-112
SVE-113
H12
SVE-201
SVE-202
SVE-203
SVE-204
SVE-205
SVE-206
SVE-207
SVE-208
SVE-209
SVE-210
SVE-211
SVE-212
SVE-301
SVE-302
SVE-303
SVE-304
SVE-305
SVE-306
Screened Interval
(ftbgs)
4.5-11.5
6.5-11.5
4.0-11.5
4.0-11.5
4.0-11.5
3.0 - 10.5
5.5 - 13.0
5.0 - 12.5
5.0 - 12.5
5.0 - 12.5
5.0 - 12.5
5.0 - 12.5
4.0-11.5
10
8.0 - 15.5
8.0 - 20.5
7.5 - 17.5
11.5-21.5
10.5 - 20.5
10.5 - 20.5
9.5 - 24.5
8.0 - 25.5
10.0 - 22.5
15.0 - 30.0
13.0 - 30.5
14.0 - 32.5
11.0-28.5
9.5 - 27.5
13.5-26.0
10.5 - 23.0
10.5 - 23.0
9.0 - 24.0
Total Depth (ft. bgs)
11.5
11.5
11.5
11.5
11.5
10.5
13.0
12.5
12.5
12.5
12.5
12.5
11.5
10
15.5
20.5
17.5
21.5
20.5
20.5
24.5
25.5
22.5
30.0
30.5
32.5
28.5
27.5
26.0
23.0
23.0
24.0
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- Sand Creek Industrial Superfund Site, O.U. 1, Page 12 of 31
| TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
Figure 5 shows a schematic of the SVE system. As shown in Figure 5, three 1,500 ACFM
positive displacement blowers were used to create a vacuum, with two of the three blowers
operated at one time. Extracted water was separated from the vapors using an air/water
separator. Following separation, extracted vapors were diluted with ambient air (between 12%
and 50% by volume) and treated using a catalytic oxidizer. The emissions from the catalytic
oxidizer were either re-injected into the soil through the vertical and horizontal wells, or released
to the atmosphere. The system included two blowers for air injection, operated one at a time.
The vendor reported that the FIVE system is described in the following reference: Kirk, J.L. and
J.R. Ohneck, "A Portable Method for Decontaminating Earth," U.S. Patent No. 4,435,492, U.S.
Patent and Trademark Office, Washington, D.C., March 6,1984.
Ambient
Air
To
Atmosphere
Soil Vapor
n
/•*& «
Air/Water
Separator
Catalytic
Oxldlzer
To Air
Injection
Wells
Temporary
> ->Wastewater
Storage Tank
/
Extraction/Injection
Wells
(32 wells total)
Figure 5. SVE System Schematic [based on 8,10]
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Sand Creek Industrial Superfund Site, O.U. 1, Page 13 of 31
| TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
Operation [8,12,14]
The SVE system was operated for two periods - September to December 1993, and January to
April 1994. SVE system start-up activities began on September 24,1993 and the system became
fully operational by October 12,1993.
Start-up activities focused on well development (initial purging activities), which took place 24
hours a day. Well development was limited to 2 to 3 wells per day to balance the relatively high
concentrations of VOCs in the vapors extracted during development and the capacity of the
catalytic oxidizer.
Extraction quantities varied during the remediation based on the capacity of the catalytic
oxidation (CATOX) unit (extracted vapors had to be maintained at less than 25% of the lower
explosive limit (LEL) of vapors in air). Early in the remedial action, the concentration of VOCs
in the extracted vapors was high and few wells could be used for extraction because of "over-
heating" of the CATOX unit. Later on, the concentration of VOCs in the extracted vapors was
less, and all wells in the system could be used in extraction mode.
Treated vapors were intermittently injected into the soil. In October 1993, approximately 25% of
the extracted and treated vapors (i.e., after CATOX) were re-injected into Subareas 2 and 3. In
November 1993, approximately 15% of the extracted and treated vapors were re-injected into all
three subareas. During December 1993, vapors were re-injected into Subarea 1 for nine days.
Treated vapors were released directly to the atmosphere during January through April 1994.
The treatment vendor described their general approach to determining injection quantities as
follows: (1) at the start of a remediation (when highly concentrated vapors are being extracted),
injection must be limited to prevent fugitive emissions from the ground surface or uncontrolled
migration of vapor plumes; (2) later on in the remediation, additional injection wells could be
brought into service to thermally enhance volatilization, reduce contaminant liquid viscosity, and
improve flushing efficiency between adjacent injection and extraction wells; and (3) towards the
end of a remediation (when VOC contaminant concentrations are lowest, and are least amenable
to further extraction), lower injection flows (and corresponding lower extraction volumes) would
lead to conditions conducive to biodegradation (e.g., oxygen enhancement, elevated temperature,
adequate moisture). At Sand Creek, it appears that the vendor used limited injection throughout
the remediation (25% in Month 1, 15% in Month 2, limited in Month 3, and none in Months 4-7).
No data were provided in the available references on any potential fugitive emissions or
uncontrolled migration at Sand Creek, or on how much the use of injection improved treatment
system performance through thermally-enhanced volatilization, reduced contaminant liquid
viscosity, improved flushing efficiency, or biodegradation.
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Sand Creek Industrial Superfund Site, O.U. 1, Page 14 of 31
| TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.)
System operation generally took place without equipment failure or shutdown. However, in
March 1994, the system was automatically shut down twice. On March 1, a shutdown occurred
because the high temperature set point was exceeded on the catalytic oxidizer. The system was
restarted after about 5 hours. On March 8, the system shut down a second time because of flame
failure. The system was restarted one-half hour later.
Groundwater Removal and Disposition [8,12,14]
From October 1993 through April 1994, the extraction wells removed entrained groundwater
from the subsurface, however, no provisions were made for a water treatment system. The water
was temporarily stored on site in a storage tank until disposal at an approved facility. On
February 21,1994, approximately 3,750 gallons of entrained water were disposed at Enviroserve,
Inc. Between February 21,1994 and April 27,1994, approximately 1,700 gallons of entrained
water were collected. No additional information was provided on the disposition of water
collected between February and April 1994.
The water extraction rate varied with rainfall, and the presence of perched water and fluctuating
water tables. The extraction rate of entrained groundwater from October 1993 to February 1994
was estimated as 10 gallons per day. During March 1994, the rate of entrained groundwater
extraction increased to approximately 30 gallons per day, possibly due to a spring snow melt. In
April, the rate dropped to about 25 gallons per day.
System Shutdown [8, 12]
The soil vapor extraction system was temporarily shut down on April 19, 1994 for soil
confirmation sampling and to assess cleanup of the site. Based on these results (presented under
treatment performance data), no additional operation of the SVE system was needed and the
system was permanently shut down by April 27.
The treatment performance data shown later in this report indicate that cleanup criteria were met
in November 1993, however, according to the RPM, system operation was continued until April
1994 because of the structure of the contract and information about non-target VOC removal
quantities. According to the RPM, system operation was performed under a fixed-price contract,
where the only benefit to an earlier shutdown would be for oversight costs paid to the prime
contractor. These oversight costs were less than the estimated costs for demobilization and a
possible subsequent remobilization (for example, if vapor headspace concentrations had
increased after a shutdown period), and the RPM determined that shutdown in November 1993
would not be "cost efficient." In addition, during the November 1993-April 1994 operating
period, the RPM reported that "significant" quantities of non-target VOCs were being removed
by the SVE system.
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Sand Creek Industrial Superfiind Site, O.U. 1, Page 15 of 31
I TREATMENT SYSTEM DESCRIPTION (CONT.)
Soil Vapor Extraction System Description and Operation (cont.) .
On June 22 and June 23,1994, the extraction wells were abandoned in place. They were grouted
with a 9 to 1 ratio of cement/bentonite. The vacuum extraction/injection blowers, catalytic
oxidizer, LEL monitoring control system, and decontamination trailer were reconditioned and
reconfigured to be used in remediation of O.U. 4 at the Sand Creek site.
Operating Parameters Affecting Treatment Cost or Performance
The major operating parameters affecting cost or performance for this technology and the values
measured for each are shown in Table 4.
Table 4. Operating Parameters [8]
Parameter
Air Flow Rate
Operating Pressure/Vacuum
Air Injection Rate
September to
December 1993
2,681 scfin
22-24 inches of water
column
605 scfin under 12
inches of water
column pressure
January to April 1994
2,910sqfm
13.4 to 23.8 inches of
water column
483 scfm under 18.3
inches of water column
pressure
Measurement Method
N/A
N/A
N/A
N/A - Measurement method not reported for this parameter because resulting value not expected to vary
among measurement procedures.
Timeline
A timeline for this application is shown in Table 5.
TableS. Timeline [4, 8, 14]
Start Date
1982
1984
September 29, 1989
September 8, 1993
September 24, 1993
September 1993
December 22, 1993
January 1994
April 19, 1994
April 27, 1994
June 22, 1994
December 20, 1996
End Date
-
1988
-
-
October 12, 1993
December 1993
January 5, 1994
April 1994
April 27, 1994
-
June 23, 1994
-
Aetivify
Sand Creek site placed on NPL
Site-wide Remedial Investigation conducted
ROD signed for O.U. 1
BSD signed for O.U. 1
System started up and wells developed
First period of operations
System temporarily shutdown for the holiday season
Second period operations
System shut down for confirmation soil boring
Shutdown of S VE system
Extraction wells abandoned in place
Sand Creek site removed from NPL (61 FR 67233)
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Sand Creek Industrial Superfund Site, O.U. 1, Page 16 of 31
I TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards
The ROD for O.U. 1 specified soil cleanup goals for four VOCs, as shown in Table 6.
Table 6. Soil Cleanup Goals for VOCs at O.U. 1 [1]
* ? , ? =• ^ " *', ' *=""
- „ ,fc ~ ,€ompoiiitd -- ~ . \
Chloroform
Methylene Chloride
Trichloroethene (TCE)
Tetrachloroethene (PCE)
/ • Cleanup Goals (mg/kg)
0.165
0.075
0.285
1.095
An air emissions operating permit was not obtained for this application, however, air emissions
were regulated under an Air Pollution Emission Notice (APEN) effective December 30,1992,
issued by the Colorado Department of Health under Regulation No. 3. The notice required
reporting of air emission quantities, but did not limit the emissions. [14]
Addition Information on Goals
The soil cleanup goals for VOCs were developed based on the results of a risk assessment for the
site. The risk assessment identified a groundwater ingestion pathway as the most significant
route for exposure to VOCs, based on a review of the relatively low partitioning coefficients for
the specific contaminants. The cleanup goals were calculated based on this pathway and using a
1Q-6 risk level. [1]
Treatment Performance Data ,
Treatment performance data for the SVE application at O.U. 1 consists of confirmation soil
borings, equilibrium headspace sampling, mass extraction data, and catalytic oxidizer destruction
efficiency data.
Confirmation Soil Borings F81
On April 19, 1994, OHM began confirmation soil boring. Thirty-two confirmation soil borings
were performed in O.U. 1. Sixteen soil borings were performed in SVE-1, 11 borings were
performed in SVE-2, and 5 borings were performed in SVE-3. Confirmation soil borings were
performed using a CME-55 truck mounted drilling rig with 7-inch, outside diameter, hollow-stem
augers. Soil samples were collected using a series of 2-inch outside diameter by 2-foot long
California Split Spoon Samplers in accordance with ASTM Method D-1586.
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Sand Creek Industrial Superfund Site, O.U. 1, Page 17 of 31
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Following decontamination of the split spoon samplers, four 6-inch brass sleeves were placed
into the sampler.
Once the sampler was retrieved from the boring, the split barrel was opened and the brass sleeves
removed. Teflon sheeting was placed over each end of each 6-inch brass sleeve and capped with
Teflon caps. For each split spoon sampler retrieved, four soil samples were generated, one for
lithology characterization using the Unified Soil Classification System (USCS, ASTM Method
D-2488), one for backup, one for on-site analytical screening, and one for off-site laboratory
analysis. In addition, QA/QC samples were collected during the field sampling event. These
samples included trip blanks, field blanks, and equipment rinse water.
Field analyses of the soil boring samples were performed according to Method 8010B, published
in SW-846, "Test Methods for Evaluating Solid Waste," and using a Hewlett Packard Series n
Gas Chromatograph (GC), configured with a Tekmar ALS 2016 Purge and a Tekmar LSC 2000
Trap for sample introduction. An OI Corp. 5220 Electrolytic Conductivity Detector (BCD) was
used for quantitation of the target compounds.
Off-site laboratory analyses were performed by Great Lakes Analytical Laboratory in Buffalo
Grove, Illinois. Trip; blanks and equipment blanks also were analyzed by Great Lakes Analytical
Laboratory.
Table 7 shows the results from the off-site laboratory analyses for the four target constituents in
the confirmation soil borings. Only those borings where at least one constituent was measured at
a detectable concentration are shown on Table 7. Samples for off-site analysis were collected
between April 19 and May 2,1994.
Equilibrium Headspace Sampling [81
Equilibrium headspace sampling was performed in September, November, and December 1993,
and in March 1994. Prior to sampling, the SVE system was shut down by closing the valves in
the system, including 10-inch headers located in the equipment pad area, 4-inch well head valves,
and extraction/injection manifold 4-inch valves. The SVE system was shut down for a minimum
of 48 hours to allow sufficient time for the vapors in the wells to reach a state of equilibrium.
After equilibration, the SVE system was re-started and operated 5 to 10 minutes, and well head
(static vapor) samples were collected.
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Sand Creek Industrial Superfund Site, O.U. 1, Page 18 of 31
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 7. Analytical Results from Off-Site Laboratory
A ~ j,
\
- Soil Boring
Cleanup Goal ~
CB-1
CB-1
CB-2
CB-12
CB-17
CB-18
CB-18
CB-19
CB-19
CB-21
X f~ t 3
Bepth*
- (ft bgs) .
•*• ~~ _ *
jf " " •-
5-7
10-12
3-5
11-13
7-9
15-17
17-19
7-9
9-11
19.5-20
GMoreSbntf—
JCipgfcg)
-- ,*OA«f ;V
ND
ND
ND
ND
0.0078
0.0069
0.0099
ND
ND
0.0071
? Methylstte ^
Chloride f
~twig&g)
- "0.075 ' ~r
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Trffihloroeftfcne^
' ~ (mg/kg) -
; /JO285-- ;-
ND
ND
ND
ND
ND
ND
0.10
ND
ND
ND
) -L -*' ~
Tetrachloroethene
Jnig/kg) r" ,
r / 4,095f . ~
0.200
0.005
0.032
0.280
ND
ND
ND
0.0063
0.0059'
0.066
ND - Not detected (detection limits not provided).
*Off-site laboratory analyses were performed for 61 samples (i.e., soil borings at specific depths). Only those
10 samples where at least one constituent was measured at a detectable concentration are shown on this
table. All other samples were reported as ND for all four target constituents.
Table 8 summarizes the results from equilibrium headspace sampling in Subareas 1,2, and 3
during September, November, and December 1993, and March 1994. As shown in Table 8, an
equilibrium headspace equivalent to the soil cleanup goals was identified for the four VOC target
contaminants. This value was calculated using Henry's Law Constant as an indicator of the
relationship between headspace soil vapor concentrations and soil concentrations. Headspace
equivalent values were calculated with values taken from the technical literature, and field
sampling to validate Henry's Constant, porosity, moisture content, temperature, or partition
coefficients used to compute headspace equivalent was not conducted.
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Sand Creek Industrial Superfund Site, O.U. 1, Page 19 of 31
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 8. Equilibrium Headspace Results for VOCs in O.U. 1 -
Maximum Concentrations (mg/L) [8]
Sampling
Date/Location
Equilibrium
Headspace
Equivalent to
Soil Cleanup
Goal*
Chloroform
0.139
Methylene
Chloride
0.05
Trichloro-
ethene
0.311
Tetrachloro-
ethene
0.856
Total VOCs
Not calculated
September 1993
Subarca 1
Subarea 2
Subarea 3
BDL
0.0178
BDL
BDL
BDL
BDL
BDL
0.154
BDL
0.06
6.9
0.3
57.7
14.0
2.4
November 1993
Subarca 1
Subarca 2
Subarca 3
0.001
BDL
0.001
BDL
BDL
BDL
0.002
BDL
BDL
0.001
0.078
0.002
33.6
0.547
0.10
December 1993
Subarea 1
Subarca 2
Subarea 3
NA
BDL
BDL
NA
BDL
BDL
NA
0.001
BDL
NA
0.104
0.001
NA
1.55
0.064
March 1994
Subarea 1
Subarea 2
Subarea 3
NA
NA
0.001
NA
NA
BDL
NA
NA
0.001
NA
NA
0.005
NA
NA
0.005
*Calculated using Henry's Law - see text.
NA - Data not contained in available references.
BDL - Below detection limit.
Mass Extraction Data [8,12, 14]
Table 9 summarizes the mass extraction rates and mass removal quantities for the target VOCs
and total VOCs during the first and second periods of SVE operation. Removal rates shown in
Table 9 represent the average rates measured during the time period.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superfund Site, O.U. 1, Page 20 of 31
| TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 9. Mass Extraction Rates and Mass Removal Quantities for
SVE System Operation [8]
Parameter ~" ^
Average Removal Rate for Target
Compounds (Ibs/day)
Average Removal Rate for Total
VOCs (Ibs/day)
Mass Extracted for Target
Compounds (Ibs)
Mass Extracted for Total VOCs
(Ibs)
- September to December 1993
33.86
1,482.6
2,899.7
122,456.6
- January to April 1994 ^
3.15
482.4
349.6
53,547
NOTE: Total VOCs were analyzed using a modified EPA Method 8015. Non-halogenated VOCs, including the
volatile portions of any semivolatiles present were measured, with gasoline range hydrocarbons prevalent in
the chromatographs. Average mass extraction rates of contaminants were computed by multiplying the
mean concentration by the mean volumetric flow rate between successive sampling episodes and converting
to a daily rate (Ib/day).
Table 10 shows the cumulative mass of target compounds and total VOCs extracted from the
three subareas, released to the atmosphere through stack emissions, and re-injected into the soil.
Data in Table 10 represent the cumulative mass over the entire period of system operation, from
September 24, 1993 to April 27, 1994.
Total VOCs were analyzed using a modified EPA Method 8015. Non-halogenated VOCs,
including the volatile portions of any semivolatiles present were measured, with gasoline range
hydrocarbons prevalent in the chromatographs. Average mass extraction rates of contaminants
were computed by multiplying the mean concentration by the mean volumetric flow rate between
successive sampling episodes and converting to a daily rate (Ib/day).
Catalytic Oxidizer Destruction Efficiency Data
The destruction efficiencies for the catalytic oxidizer are shown in Table 11, by operating period.
Average destruction efficiencies are shown for target compounds and total VOCs. Destruction
efficiency was calculated as follows [14]:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superfund Site, O.U. 1, Page 21 of 31
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Treatment Performance Data (cont.)
Table 10. Cumulative Mass of Contaminants Extracted, Released to the Atmosphere,
and Re-injected -September 24,1993 through April 27,1994 (Ibs) [8]
Target Compounds
Methylene
Chloride
Chloroform
Trichloro-
ethene
Tetrachloro-
ethene
' >•
Total Target .
Compounds*
-
Total
VOCs*
Extraction
Subarea 1
Subarea 2
Subarea 3
Total
0.0
0.0
0.0
0.0
0.0
0.40
13.4
13.8
0.0
35.2
0.0
35.2
5.2
3,130.7
69.8
3,205.7
5.2
3,166.3
83.2
3,254.7
69,096.7
106,232.6
1,175.2
176,504.5
Release to Atmosphere
Stack Emission
0.0
0.0
0.0
209.6
209.6
6,210.3
Injection
Total
0.0
0.0
0.0
0.74
0.74
638.9
Totals reflect rounding.
Table 11. Catalytic Oxidizer [8]
Parameter
Target Compounds Destruction
Efficiencies (%)
Total VOCs Destruction
Efficiencies (%)
September to December 1993
92.9
95.5
January to April 1994
99.1
98.8
Destruction Removal Efficiency = [1 - [(Minj + Ms)/Mext]] x 100%
where:
Ms
Mass of contaminant injected to the subsurface (Ib/day)
Mass of contaminant emitted from the stack (Ib/day)
Mass of contaminant extracted from the subsurface (Ib/day)
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superfund Site, O.U. 1, Page 22 of 31
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment
The treatment performance data shown in Table 7 indicate that the SVE system used at Sand
Creek met the soil cleanup goals for VOCs within 6 months of operation. Soil concentrations
were reduced from as high as 9.34 mg/kg (the maximum concentration shown in the RI for
tetrachloroethene) to less than the cleanup goals. The maximum concentration of target
constituents measured by the off-site laboratory for the confirmation soil borings was:
chloroform - 0.0099 mg/kg; methylene chloride - not detected; trichloroethene - 0.10 mg/kg; and
tetrachloroethene - 0.28 mg/kg. In addition, as discussed in Table 7, less than 20% of the soil
boring samples (i.e., soil borings at specific depths) contained at least one target constituent
measured at a detectable concentration.
Equilibrium headspace results shown in Table 8 indicate a reduction in contaminant levels over
the course of the remediation. For example, these data show a reduction for tetrachloroethene
from 6.9 mg/L in September 1993 (Subarea 2) to 0.104 mg/L in December 1993 (Subarea 2), and
from 0.3 mg/L in September 1993 (Subarea 3) to 0.005 in March 1994 (Subarea 3). The
headspace results also provide an indication of the variations in contaminant levels between
subareas. For example, these data show a relatively higher level of contamination in Subarea 2
than in Subareas 1 or 3. The relatively higher concentrations in Subarea 2 are further supported
by the cumulative mass extraction data shown in Table 10. For example, Table 10 shows that
3,166.3 Ibs of the 3,254.7 Ibs (97.3%) of target compounds were extracted from Subarea 2.
Mass extraction rate and mass removal quantity data provided in Table 9 also show a reduction
in contaminant quantities over the course of the remediation. For example, the average removal
rate for target compounds was reduced ten-fold from the first to second periods, from 33.86 to
3.15 Ibs/day.
As shown in Table 10, approximately 3,250 Ibs of the four target VOC compounds and 176,500
Ibs of total VOCs were extracted from the three subareas at O.U. 1. Tetrachloroethene accounted
for approximately 98.5% of the mass of target compounds extracted from the subareas. Table 10
also shows that during the 6 months of SVE operation, approximately 6,200 Ibs of total VOCs
were released to the atmosphere, including approximately 209.6 Ibs of tetrachloroethene. An
estimated 0.74 Ibs of tetrachloroethene were re-injected into the soil.
As shown in Table 11, the average destruction efficiencies for the catalytic oxidizer ranged from
92.9 to 99.1% during the 7 months of SVE system operation. Treatment performance data are
not provided in the available references to compare actual air emissions with regulatory levels.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superfimd Site, O.U. 1, Page 23 of 31
I TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Completeness
Analytical data are available for the following: 1) the maximum concentrations of contaminants
in the soil prior to treatment, as reported in the RI; 2) the range of operating conditions of the
SVE system during treatment; 3) analytical data for soil boring confirmation samples; 4) the
reduction in equilibrium headspace concentrations over the course of the remediation; and 5)
other process parameters, such as rate and mass of extracted VOCs, release of VOCs to the
atmosphere, and destruction efficiency of the catalytic oxidizer.
No data are available to characterize the actual soil concentrations in 1993, at the time just prior
to treatment system operation. Data are available from the mid-1980s for VOCs in the soil when
the RI was performed.
Performance Data Quality
The treatment vendor performed quality assurance/quality control (QA/QC) procedures as part of
this application, including use of standard EPA analytical methods, analysis of duplicate
samples, trip blanks, and equipment blanks. No deviations to the QA/QC protocols were noted
by the vendor. [8]
Soil samples from confirmation soil borings were processed in accordance with the URS-
approved Chemical Quality Management/Sampling Plan, Soil Vapor Extraction Remedial
Action, Sand Creek Industrial Superfund Site, OU-1 Commerce City, Colorado," dated October
20, 1993, and "Subcontractor Quality Control Plan, OHM Remediation Services Corp.," June 17,
1993. The QA/QC results are contained in OHM's "Cleanup Demonstration Results for Subarea
SVE-1, SVE-2 and SVE-3," (Appendix C), dated March 17,1995. [14]
US. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
100
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Sand Creek Industrial Superfund Site, O.U. 1, Page 24 of 31
TREATMENT SYSTEM COST
Procurement Process
The SVE application at Sand Creek O.U. 1 was procured by EPA Region 8 through an ARCs
contract with URS Consultants, Inc. (URS). URS prepared detailed bidding and subcontract
requirements for the SVE application, including a description of the work, summary of site
conditions, and startup, testing, and operating requirements. URS selected OHM Remediation
Services Corp. (OHM) under a fixed price subcontract to design, construct, and operate the SVE
system in accordance with a URS performance specification. [4, 8,14] According to the RPM,
the remediation was competitively bid, with four bidders. Selection was based on technical
criteria and cost, including use of a best and final offer (BAFO) approach. [12]
During the procurement period, EPA revised the air emissions control equipment from activated
carbon to catalytic oxidation because of the relatively large quantity of non-target VOCs in the
soil (approximately 98% of the total VQCs removed). The ARCs contractor estimated that
carbon disposal costs would have exceeded the cost for catalytic oxidation by approximately
$600,000 to $750,000. [11] The treatment vendor indicated that savings from use of catalytic
oxidation rather than carbon with off-site regeneration may have been greater than the estimate
of $600,000 to $750,000, based on the following analysis: A total of approximately 176,500 Ibs
of VOC were extracted from site soils. If a carbon adsorption capacity of 10 percent was
assumed, 10 Ibs of carbon would be needed to adsorb one pound of VOC, and approximately
1,765,000 Ibs of carbon costing $1.50/lb or a total of $2,647,500 would be required for this
application. The vendor stated that this suggested that nearly $2 million might have been saved
by selecting catalytic oxidation. [14]
Treatment System Cost [1,2, 12]
Actual treatment system costs of approximately $2.14 million were provided by EPA Region 8
for this treatment application. This value does not include costs for demobilization activities;
costs for these activities are not available at this time. [9]
In order to standardize operating costs across projects, costs reported by Region 8 were
categorized according to an interagency Work Breakdown Structure (WBS), as shown in Tables
12 and 13. Table 12 shows that $81,231 in costs for this application were incurred for before-
treatment activities such as mobilization and preparatory work, and monitoring, sampling,
testing, and analysis. Table 13 shows that $2,058,564 were incurred for activities directly
attributed to treatment, such as short-term operation and cost of ownership. Approximately 82%
of the costs directly attributed to treatment were for the treatment vendor for this application.
As discussed under the section on Quantity of Soil Treated, the estimates for the quantity of soil
treated during this application varied from 31,440-52,920 cubic yards. Because of this, the cost
per cubic yard of soil treated is presented as a range, rather than a single cost number. Therefore,
the $2,058,564 in costs attributed to treatment corresponds to $39-65 per cubic yard of soil
treated (31,440-52,920 cubic yards) and $11.70 per pound of VOC removed (176,500 Ibs).
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
101
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Sand Creek Industrial Superfund Site, O.U. 1, Page 25 of 31
| TREATMENT SYSTEM COST (CONT.)I
Treatment System Cost (cont.)
Table 12. Before Treatment Costs [9]
Cost Element
Mobilization and Preparatory Work
- Work plan revisions, addendum, and response to interrogatories
- Coordination with Operable Units 4 and 5
Monitoring, Sampling, Testing, and Analysis
- Confirmatory sampling
- QA/QC laboratory analyses
Total
1 Unit Cost ($>
4,117
27,137
15,569
34,408
Cost(D
31,254
49,947
81,231
Table 13. Treatment Costs [9]
Cost Element
Operation (short-term - up to 3 years)
- Subcontractor costs
- Project management/administrative
- SVE remedial work (1993)
- SVE remedial work (1994)
- Other costs (RA, Area 1, 2, 3, SVE, community relations,
TSOPs, travel, ODCs, reporting, and closeout)
Cost of Ownership
- Overhead adjustment
- Unallowable costs
Total
Uirit:Cost{$)
1,693,260
234,859
105,899
55,216
27,676
(55,088)a
(3,258)a
^M®ost;<$)' ;*
2,116,910
(58,346)"
2,058,564
"Values in parentheses represent credits (i.e., amount that vendor deducted from total treatment cost).
Cost Data Quality
The costs described above represent actual costs for this treatment application as reported by
EPA Region 8. Limited information is available on the specific activities included within several
of these cost elements. Tables 12 and 13 show the available information.
Vendor Input
URS (the prime contractor) provided the following information on SVE remediation [13]:
There are a number of items that can affect the cost and opportunities for reductions in costs for
similar projects to be completed in the future.
(1) The most important factor is to adequately characterize the site and to identify the aerial
extent and the vertical zones of contamination. This is necessary to adequately
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Sand Creek Industrial Superftmd Site, O.U. 1, Page 26 of 31
| TREATMENT SYSTEM COST (CONT.)I
Vendor Input (cont.)
remediate the site and prevent cost growth during remediation as a result of "unforeseen
site conditions." Change orders during cleanup will substantially impact the ultimate
remediation cost. The detailed site characterization should be performed as part of the
remedial design phase rather than the RI/FS phase. This will ensure that the design
engineers obtain the "design related data" rather than less detailed and specific data
required to produce the RI.
(2) The site must be adequately characterized to ensure that all soil contaminants that will
impact the SVE process are quantified. As a case in point, only approximately 2% of the
total contaminants removed were target analytes. There are cases where the total
quantity of contaminants were not characterized, resulting in large project cost increases
because inappropriate air pollution control technologies were specified.
(3) Innovative contracting strategies can provide opportunities for cost reductions. For
example, rather than using a traditional firm fixed price contract, a two step procurement
with a fixed price variable quantity contracting strategy could be used. This contracting
strategy would provide for a firm fixed price for mobilization, installation and startup of
the SVE system. There would also be a firm fixed price for a base period of operation.
At the Sand Creek Industrial Superfund Site this could have been two months. The base
period of system operation would then be followed by multiple fixed price option time
periods. This approach will provide the selection of the best technical approach at the
lowest estimated cost. It will also allow EPA to take advantage of cost reductions when
a quick site cleanup occurs and pay a reasonable cost if the remediation takes longer.
There will also be corresponding reductions to the Remediation Contractor's pricing
because of reduced risk for the Contractor.
OHM (the treatment vendor) indicated that cost reduction is directly related to increasing
productivity, reducing remediation time, and encouraging innovation. [14]
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
103
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Sand Creek Industrial Superfund Site, O.U. 1, Page 27 of 31
OBSERVATIONS AND LESSONS LEARNED
Cost Observations and Lessons Learned
Approximately $2.14 million were expended for SVE treatment of O.U. 1 at Sand Creek,
including $81,231 in before-treatment costs, and $2,058,564 in costs directly attributed
to treatment.
The $2,058,564 in costs directly attributed to treatment corresponds to $39-65 per cubic
yard of soil treated (31,440-52,920 cubic yards) arid $11.70 per pound of VOC removed
(176,500 pounds). A range of costs is presented because of the variation in estimates of
the quantity of soil treated. Estimates were provided using the average groundwater
depth and average smear zone depth to calculate soil quantity treated.
EPA's.decision to revise the air emissions control equipment from activated carbon with
off-site regeneration to catalytic oxidation (CATOX) resulted in a cost savings to the
government. The prime contractor estimated the savings to be $600,000 to $750,000,
while the treatment vendor estimated the savings as nearly $2,000,000. EPA revised the
control to CATOX because of the relatively large quantity of non-target VOCs in the
soil.
The RPM stated that there was limited benefit in shutting down the system in November
1993 when the operating data indicated that the cleanup criteria for target contaminants
had been met. For example, the system was still removing significant quantities of non-
target petroleum hydrocarbons. Although operating data (e.g., wellhead vapors) are
becoming more acceptable as an indicator of soil concentrations, the vendor indicated
that there was reluctance to perform confirmation soil borings in November 1993, and
the system continued to operate until April 1994 when confirmation soil borings
indicated the cleanup criteria had been met. Early shutdown would have saved EPA
from paying oversight costs to the prime contractor (URS). However, had EPA shut
down the system in November 1993, and then found an increase in wellhead vapor
concentrations, EPA would have incurred additional costs for demobilization and
reraobilization.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
104
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Sand Creek Industrial Superfund Site, O.U. 1, Page 28 of 31
OBSERVATIONS AND LESSONS LEARNED
Cost Observations and Lessons Learned (cont.)
• The prime contractor identified several items that should be considered in future SVE
applications for reducing costs:
a detailed site characterization should be performed as part of the remedial
design rather than the RI/FS, to identify the aerial extent and vertical zones of
contamination, and to identify the total quantity of contaminants, including
target and non-target contaminants. At Sand Creek, only approximately 2% of
the total contaminants removed were target analytes.
innovative contracting strategies may provide a potential for cost savings with
this technology as alternatives to traditional firm fixed-price contracts. For
example, a two-step procurement with a fixed price contract for mobilization,
installation, and system startup, followed by multiple fixed price option periods
for system operation, would likely result in lower costs for SVE projects.
Performance Observations and Lessons Learned
• Analytical data from off-site laboratory analyses of confirmation soil borings indicate
that the SVE system used at Sand Creek met the soil cleanup goals for VOCs within 6
months of operation.
• Soil concentrations were reduced from as high as 9.34 mg/kg (the maximum
concentration shown in the RI for tetrachloroethene) to less than the cleanup goals. The
maximum concentration of target constituents measured by the off-site laboratory for the
confirmation soil borings was: chloroform - 0.0099 mg/kg; methylene chloride - not
detected; trichloroethene - 6.10 mg/kg; and tetrachloroethene - 0.28 mg/kg. In addition,
less than 20% of the soil boring samples (i.e., soil borings at specific depths) contained
at least one target constituent measured at a detectable concentration.
• Equilibrium headspace results, and VOC extraction rate and mass results, indicate a
reduction in contaminant levels and quantities over the course of the remediation. For
example, equilibrium headspace results show a reduction for tetrachloroethene from 6.9
mg/L in September 1993 to 0.104 mg/L in December 1993 (Subarea 2), and from 0.3
mg/L in September 1993 to 0.005 mg/L in March 1994 (Subarea 3).
* Approximately 3,250 Ibs of the four target VOC compounds and 176,500 Ibs of total
VOCs were extracted from the three subareas at O.U. 1. Tetrachloroethene accounted
for approximately 98.5% of the mass of target compounds extracted from the subareas.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
105
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Sand Creek Industrial Superfund Site, O.U. 1, Page 29 of 31
! OBSERVATIONS AND LESSONS LEARNED (CONT.)
Other Observations and Lessons Learned
• The average quarterly destruction efficiency for the catalytic oxidizer ranged from 92.9
to 99.1% during the 6 months of SVE system operation.
• The mass of target compounds removed from the soil (3,250 pounds) was approximately
4.75 times greater than the original estimated mass of target compounds (684 pounds),
determined based on preremedial target compound concentrations and estimated in situ
soil volume reported in the remedial design report. According to the RPM, the reason
for the difference was based on sampling and analysis for VOCs in the soil prior to
remediation. According to the RPM, sampling and analysis of VOCs in soil can often be
biased low, because of VOC losses in the sampling processes. In addition, according to
the RPM, the pre-remediation VOC results may not have been representative of the zone
of influence of the SVE wells.
• The treatment vendor used their patented Fluid Injection/Vapor Extraction (FIVE)
technology in this application. The vendor stated that this system "enhanced subsurface
volatilization and shortened the period of remediation."
• The CATOX unit was a limiting factor in determining the number of wells that could be
used for extraction. Early in the application, the concentration of contaminants in the
extracted soil vapors was high, and the number of wells had to be limited so as not to
overheat the CATOX unit. Later in the application, when the vapor concentrations were
less, all wells in the system could be used for extraction.
• The vendor's bid for this application included use of both horizontal and vertical wells,
with "preference" given to horizontal wells, because the vendor believed that horizontal
wells would increase the radius of influence. At that time, the use of horizontal wells for
SVE was not widely practiced, and was considered an emerging technology. However,
during installation of the first horizontal well at Sand Creek, the vendor discovered
buried concrete blocks and other construction debris in the subsurface, and these items
caused an increase in the cost and time required for horizontal well installation. As a
result, the vendor abandoned their plan to give preference to horizontal wells. Instead of
installing two additional horizontal wells, additional vertical wells were installed.
U.S, ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
106
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Sand Creek Industrial Superfund Site, O.U. 1, Page 30 of 31
REFERENCES
1. Record of Decision, Sand Creek Industrial, Commerce City, CO, Operating Unit #1, September
29, 1989.
2. Explanation of Significant Differences. Soil Cleanup of OU 1—Sand Creek Superfund Site.
September 8, 1993.
3. Remedial Investigation Site Characterization Report. Sand Creek Industrial Site, Commerce
City, Colorado. March 4, 1988.
4. Project Manual for Soil Vacuum Extraction Remedial Action, Sand Creek Industrial Superfund
Site, Operable Unit No. 1. Commerce City, Colorado. URS Consultants, Inc. September 9,
1992.
5. Sand Creek Industrial Superfund Site, Operable Unit No. 4 (OU 4), Technical Assistance,
Remedial Investigation/Feasibility Study, Commerce City, Colorado, Remedial Investigation
Report, Volume I, September 1993.
6. Sand Creek Industrial Superfund Site, Operable Unit No. 4 (OU 4), Technical Assistance,
Remedial Investigation/Feasibility Study, Commerce City, Colorado, Final Feasibility Study
Report, February 7, 1994.
7. Letter to Ms. Erna Acheson, U.S. EPA, from URS Consultants, Inc., regarding Sand Creek
Industrial Superfund Site OU1 RA, OHM Monthly Reports. January 30, 1995.
8. Sand Creek Industrial Superfund Site, Operable Unit No.l (OU-1) Commerce City, Colorado
Cleanup Subarea SVE-1, SVE-2, and SVE-3 Demonstration Results. OHM Remediation
Services Corp. March 17, 1995.
9. Cost Report. Sand Creek, Operable Unit 1, Monthly Report. U.S. EPA, Region VHI. March
1995.
10. John Chinnock, "Innovative Solutions Cut Cleanup Costs at Sand Creek Superfund Site."
Environmental Solutions, pp. 30-31, March 1995.
11. Draft Remedial Action Completion Report, Revision 2. Sand Creek Industrial Superfund Site,
Operable Units No. 1 (OU1) and No. 4 (OU4), Remedial Action, Commerce City, Colorado.
URS Consultants, Inc. September 20,1995.
12. Memorandum from E. Acheson, RPM, to L. Fiedler, OSWER/TIO, "Sand Creek Superfund Site,
SVE Technical Information, O.U. #1, Commerce City, CO," February 27, 1997.
13. Memorandum from J. Chinnock, URS, to E. Acheson, EPA, "Sand Creek Industrial Superfund
Site, OU 1 RA; TIO Responses," February 27, 1996.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
107
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Sand Creek Industrial Superfund Site, O.U. 1, Page 31 of 31
I REFERENCES (CONT.)
14. Letter from C. Strzempka, OHM, to E. Acheson, EPA, "Remediation Case Study Report, Soil
Vapor Extraction at the Sand Creek Industrial Superfund Site, Operable Unit No. 1, Commerce
City, Colorado, November 30,1995," February 23,1996.
15. C. Strzempka, R. Cox, R. Freasier, J. Critzer, OHM Remediation Services Corp., "Thermally
Enhanced Fluid Injection with Vacuum Extraction at a Colorado Superfund Site," Proceedings of
the Ninth National Outdoor Action Conference and Exposition, Las Vegas, NV, May 2-4,1995.
16. R. Cox, "Examining the Economics of Remediation by Fluid Injection with Vacuum Extraction,"
Remediation. Spring 1995, pp. 29-35.
17. R. Cox, "Fluid Injection Helps Vacuum Extract Contaminants," OHM Remediation Services
Corp., Brochure, Not dated.
18. R. Cox, "Fluid Injection Helps Vacuum Extract Contaminants," Soils. March 1994, pp. 8-11.
Analysis Preparation
This case study was prepared for the U.S. Environmental Protection Agency's Office of Solid
Waste and Emergency Response, Technology Innovation Office. Assistance was provided by
Radian International under EPA Contract No. 68-W3-0001 and U.S. Army Corps of Engineers
Contract No. DACA45-96-D-0016.
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Solid Waste and Emergency Response
Technology Innovation Office
108
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ENHANCEMENTS/ADDITIONS
CASE STUDIES
109
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In Situ Enhanced Soil Mixing, U.S. Department of Energy,
X-231B, Portsmouth Gaseous Diffusion Plant, Piketon, Ohio
in
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Case Study Abstract
In Situ Enhanced Soil Mixing, U.S. Department of Energy,
X-231B, Portsmouth Gaseous Diffusion Plant, Piketoii, Ohio
Site Name:
U.S. Department of Energy (DOE),
Portsmouth Gaseous Diffusion Plant
X-231B
Location:
PLketon, Ohio
Contaminants:
Chlorinated Aliphatics
- 13 VOCs were identified in the soil at
PGDP
- Most prevalent VOCs were
Trichloroethene (TCE), 1,1,1-
Trichloroethane (TCA), 1,1-Dichloroethene
(DCE), and methylene chloride
- Concentrations ranged from several
hundred to several thousand A*g/kg
Period of Operation:
June 1992
Cleanup Type:
Field demonstration
Technical Information:
Robert L. Siegrist, Prin. Inv.,
ORNL, (303) 273-3490
Vendors:
Jim Brannigan, MUlgard,
(313) 261-9760
Steve Day, Geo-Con, (916) 858-0480
SIC Code:
9711 (National Security)
Others - information not provided
Technology:
In Situ Enhanced Soil Mixing (ISESM)
- ISESM consists of soil mixing combined
. with additional technology
- Four additional technologies were
demonstrated at PGDP: vapor extraction
with ambient air injection (stripping); vapor
extraction with hot air injection (stripping);
hydrogen peroxide injection; and grout
injection for soliduication/stabUization
- 12 soil columns, each 10 ft in diameter and
15 ft deep, were treated in the
demonstration
- One additional column was treated by hot
air stripping to a depth of 22 ft
- Another additional column was used for a
tracer study
Cleanup Authority:
State: Ohio EPA
Points of Contact:
Dave Biancosino, DOE,
(301) 903-7961
Jim Wright, DOE,
(803) 725-5608
Waste Source:
Waste Treatment Plant/Disposal Pit
(waste oil biodegradation. units)
Purpose/Significance of
Application:
Application of ISESM to remediate
fine-grained soils that are difficult to
treat with other technologies alone;
technology is particularly suited to
shallow applications, above the
water table.
Type/Quantity of Media Treated:
Soil
- Detailed information provided on soil characteristics, including physical,
chemical, and biological properties
- Clay content ranged from 12 to 25%
- 78% of VOCs were present in uppermost 12 ft of soil
Regulatory Requirements/Cleanup Goals:
- Closure plan required 70% mass removal
- No RD&D permit was required
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Case Study Abstract
In Situ Enhanced Soil Mixing, U.S. Department of Energy,
X-231B, Portsmouth Gaseous Diffusion Plant, Piketon, Ohio (Continued)
Results:
- Soil mixing with each of the 4 additional technologies performed better than the 70% VOC mass removal requirement
- Soil mixing with ambient air stripping achieved >90% removal after 3.75 hrs of treatment
- Soil mixing with hot air stripping achieved >95% removal after 3.75 hrs of treatment
- Soil mixing with peroxidation achieved >70% removal after 1 hr of treatment
- Soil mixing with solidification achieved >90% capture after 1 hr of treatment
- Soil mixing with hot air (thermal) stripping was selected as the remedial option for the site, with cleanup and closure
completed in 1994; 628 soil columns at a depth of 22 ft were treated in remediation
Cost Factors:
- Actual capital costs of $1,956,000 were expended for the demonstration, including $481,000 for labor and $500,000 for
vendor subcontracts
- Equipment operating costs during demonstration were estimated at $20,000 per day
- Demonstration costs for all four technologies reported as ranging from $150-200/yd3
- Hot air stripping costs were 5% greater than for ambient air stripping, but achieved cleanup goals faster
Description:
The X-231B waste management unit at the DOE Portsmouth Gaseous Diffusion Plant (PGDP) consists of two waste oil
biodegradation areas. The unit was used from 1976 to 1983 for treatment and disposal of waste oils and degreasing
solvents, and contributed to contamination of soil and shallow ground water with VOCs. Thirteen VOCs were identified
in the soil, including TCE, TCA, DCE, and methylene chloride, at concentrations ranging from several hundred to
several thousand MgAg- The site consists of relatively low permeability soils with elevated clay content.
In situ enhanced soil mixing (ISESM) was demonstrated at the site in 1992. ISESM consists of soil mixing combined
with an additional technology. The following four additional technologies were demonstrated at PGDP: vapor
extraction with ambient air stripping; vapor extraction with hot air stripping; hydrogen peroxide injection; and grout
injection for solidification/stabilization. Three demonstration soil columns were completed for each of the four
technologies (12 total). The 12 soil columns were each 10 ft in diameter and 15 ft deep. One additional column was
treated by hot air stripping to a depth of 22 ft, and a second additional column was used for a tracer study.
Performance results showed that all four technologies performed better than the 70% VOC mass removal requirement
specified by the Ohio EPA. Removals ranged from >70% (for peroxidation) to >95% (for hot air stripping). Based on
the results of the demonstration, hot air stripping was selected for site remediation, which was completed in 1994. In
situ solidification was more complicated than originally anticipated due in part to difficulty in effectively mixing the
dense clay soil in situ and delivering the proper volume of grout. In addition, the solidification process generated
secondary liquid wastes from grout delivery trucks and equipment cleanup. An improved "grout-on-demand" system has
been developed to minimize waste.
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SECTION 1
SUMMARY
Technology Description
In Situ Enhanced Soil Mixing (ISESM) is a treatment technology that has been demonstrated and deployed to remediate
soils contaminated with volatile organic compounds (VOCs). The technology has been developed by industry and has been
demonstrated with the assistance of the U.S. Department of Energy's Office of Science and Technology and the Office of
Environmental Restoration.
• ISESM encompasses a number of in situ soil treatment technologies that can treat contaminated soils, especially those of
a fine-grained nature, which are difficult to treat with other remediation technologies. Contaminants are either removed
from the soils or stabilized in place. The mixing process allows good access for reagent delivery to all soil particles and
the interstices between particles. The technology is particularly suited to shallow applications, above the water table, but
can be used at greater depths.
• ISESM technologies demonstrated for this project include:
0 soil mixing with vapor extraction combined with ambient air injection [Contaminated soil is mixed with ambient air
to vaporize volatile organic compounds (VOCs). The mixing auger is moved up and down to assist in removal of
contaminated vapors. The vapors are collected in a shroud covering the treatment area and run through a treatment
unit containing a carbon filter or a catalytic oxidation unit with a wet scrubber system and a high efficiency particu-
late air (HEPA) filter.]
0 soil mixing with vapor extraction combined with hot air injection [This process is the same as the ambient air
injection except that hot ah- or steam is injected.]
0 soil mixing with hydrogen peroxide injection [Contaminated soil is mixed with ambient air that contains a mist of diluted
hydrogen peroxide (H2O2) solution. The H2O2 solution chemically oxidizes the VOCs to carbon dioxide (CO^ and water.]
0 soil mixing with grout injection for solidification/stabilization [Contaminated soil is mixed as a cement grout is
injected under pressure to solidify and immobilize the contaminated soil in a concrete-like form.]
• The soils are mixed with a single-blade auger or with a combination of augers ranging in diameter from 3 to 12 feet.
Mixing is likely to be effectively applied to depths of 40 feet, although commercial vendors have worked at depths as
great as 100 feet with the smaller diameter augers. Enhancements such as injection of heated air in combination with
vapor extraction, injection of oxidants, or injection of grout are utilized based on the specific system selected for a
particular site.
Illustration of the continuously mixed subsurface soil
reactor concept. (Note: treatment agents are delivered
through the mixing blade with emissions captured in
the shroud covering the mixed region.) Rigs can have
single or multiple shafts.
U.S. Department of Energy
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SUMMARY
continued
Technology Status
• In situ soil mixing, also known as deep soil mixing, shallow soil mixing, soil mixing wall, auger mixing, etc., has been
used for a number of years in the construction industry. Cement grout is typically mixed with soil to create a foundation
system or barrier wall. Soil mixing with stabilization (Geo-Con/IWT) was demonstrated under the EPA SITE Program in
1990 at a General Electric Shop in Hialeah Florida where soils were contaminated with PCB's.
• The above four ISESM treatment technologies were selected for evaluation during a full-scale field demonstration at the
Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PGDP), near Piketon Ohio. The field demonstration
was conducted at the X-231B Unit in June 1992. Replicated tests of in situ vapor stripping, peroxidation, and solidifica-
tion were made in soil columns measuring 10 ft in diameter and 15 - 22 ft deep.
• The X-231B Unit was used from 1976 to 1983 as a land disposal site for waste oils and solvents. Soils beneath the unit
were contaminated with VOCs, such as TCE at approximately 100 parts per million (ppm), and low levels of radioactive
substances. The shallow ground water (12-14 ft depth) was also contaminated, and some contaminants were above
drinking water standards. Approximately 78% of the VOCs were located in the upper 12 ft.
• Geologically the site contains low permeability sediments, composed of silt and clay deposits with hydraulic conductivities
of less than one millionth of a centimeter per second (K <10-6 cm/s).
• A computerized data acquisition system linked to approximately 60 sensors enabled near-continuous monitoring of
process operation and performance. Nearly 500 soil and gas samples were collected before, during, and after soil
treatment for analyses of physical, chemical, and biological parameters. Soil matrix, soil vapor, and off-gas VOC
measurements were made.
• The technology demonstration was a public/private partnership effort between Oak Ridge National Laboratory (six
divisions), DOE-Portsmouth Field Office, Lockheed Martin Energy Systems at Portsmouth, University of Tennessee,
Michigan Technological University, Chemical Waste Management, Millgard Environmental Corporation, Envirosurv,
and NovaTerra.
• After the demonstrations were completed, the most effective of the four technologies, thermal vapor extraction, was
selected as the remedial option for the site. Cleanup and closure of the site was completed in 1994. This innovative
treatment technology resulted in a total cost savings of $80 million as compared to traditional excavation and treatment
approaches. Closure activities were completed by Geo-Con.
• A number of companies provide ISESM technology commercially(see U.S. EPA VISITT database and DOE Commercial
Environmental Cleanup, 1995). However, this demonstration was unique in that four different ISESM technologies were
compared at a single site.
• ISESM will be demonstrated at the DOE Kansas City Plant in the spring of 1996. Mixing to a depth of 45 feet will be
accomplished and additives such as potassium permanganate, lime and bionutrients will be tested.
KEY RESULTS
In situ treatment of VOCs in clay soils was effectively (>85% reduction ) and rapidly accomplished at acceptable costs.
• Vapor stripping processes-ambient air and hot air injection:
0 Treatment performance improved with longer mixing times. 50% of the target VOCs were removed in approximately
90 minutes, whereas 92 to 98% of the contaminants could be removed in the top fifteen feet of soil if mixing were
continued for 225 minutes.
0 Extension of the zone of treatment to 22-ft depth exhibited only a moderately reduced removal efficiency (i.e. aver-
age of approximately 88%).
0 Soil bacteria levels were increased by several orders of magnitude following ambient air stripping.
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SUMMARY
* In situ peroxidation:
0 In situ peroxidation was found to treat soil more rapidly than vapor stripping.VOC treatment efficiency was approxi-
mately 72% mass removal in 75 minutes to a depth of fifteen feet.
* In situ solidification:
0 VOC treatment efficiency was over 90%. Limited VOCs were removed in the off-gas during grout injection and mixing.
• In situ treatment of VOCs in clay-rich soils was rapidly accomplished (e.g., >15 cubic yards per hour [yd3/h]).
• Treatment costs for each of the four technologies was comparable, ranging from $150 to $200 per cubic yard for the
demonstration. Further experience has brought treatment costs down (see cost section).
• Use of a hydraulic probe for soil sampling with on-site VOC analyses, followed by three-dimensional visualization,
provided enhanced information compared with conventional sampling, off-site analyses, and routine data treatment.
CONTACTS
Technical
Robert L. Siegrist, Principal Investigator, Oak Ridge National Laboratory (ORNL), (303) 273-3490.
Management
Dave Biancosino, DOE EM 50, DOE Plumes Focus Area Manager, (301) 903-7961.
Jim Wright, DOE Plumes Focus Area Implementation Manager, (803) 725-5608.
Commercial vendors
Jim Brannigan, Millgard Environmental Corporation, (313) 261-9760.
Steve Day, Geo-Con, Inc., (916) 858-0480.
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SECTION 2
TECHNOLOGY DESCRIPTION
Shakedown -
Column Area
Schematic of the test site layout for the full-scale field demonstration in the X-23 IB unit.
Overall Process Description
A mechanical system was employed to mix unsaturated or saturated contaminated soils while simultaneously injecting
treatment or stabilization agents. The main system components include the following:
0 a crane-mounted soil mixing auger,
0 a treatment agent delivery system,
0 a treatment agent supply,
0 an off-gas collection and treatment system.
The mixing system used in the demonstration was manufactured and operated by Millgard Environmental Corporation,
Livonia, MI. It is comprised of a track-mounted crane with a hollow, kelly bar attached to a drilling tool, known as the
MecTool™, consisting of one or two, 3- to 5-ft. long horizontal blades attached to a hollow vertical shaft, yielding an
effective mixing diameter of 6 to 10 feet. Depths of 40 feet can be achieved with this equipment. The 10-foot mixing
diameter was used for this demonstration.
Treatment agents were injected through a vertical, hollow shaft and out into the soil through 0.25 or 0.50 in. diameter
orifices in the back side of the soil mixing blades. Treatment is achieved in butted or overlapped soil columns. Chemical
Waste Management conducted the solidification/stabilization portion of the demonstration working in concert with
Millgard Environmental Corporation.
The ground surface above the mixed region was covered by a 14-ft. diameter shroud under a low vacuum to contain any
air emissions and direct them to an off-gas treatment process. The off-gas treatment system consisted of activated carbon
filters followed by a HEPA filter.
Removal of VOCs was enhanced by moving the mixing auger up and down from 2 to 15 ft below ground surface during
vapor stripping.
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TECHNOLOGY DESCRIPTION
continued
For the demonstration, a total of 14 soil columns, each 10 ft in diameter, were treated.
0 Each of the four treatment processes were demonstrated in three soil columns, each 15 ft. deep. Two of each set of
three columns were located in an undisturbed area, while a third, central column was placed to overlap the outer two
by approximately 40%.
0 One column was treated by the hot air stripping to a depth of 22 ft.
0 A single column, 15 ft. deep, was used for a tracer study.
0 The operating conditions for the demonstrations are summarized in Appendix B.
Soil Mixing Auger
1 1 1
1
Legend
i Pre- and post-treatment soil samples
| Vapor implant in undisturbed soil, North/South of test column
| Vapor implant in undisturbed soil, n ;
NE/SE of test column ?
D Vapor implant in mixed soil Scale in Feet
Profile view of a treated soil region and associated monitoring points.
For the X-231B closure, a total of 628 soil columns with a depth of 22 feet were treated. The closure was completed by
Goo-Con, using similar equipment.
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SECTION 3
PERFORMANCE
Demonstration Plan
The goal of the ISESM technology demonstration was reduction in the target VOCs in the treatment zone of at least
70%, to meet Ohio EPA performance standards.
Primary monitoring and measurement activities included:
0 Pre-treatment and post-treatment soil sampling
- temperature
- VOCs
- particle-bound radioactivity
0 In situ soil gas
- temperature
- pressure
- VOCs
0 Operations data
- treatment depth
- processing times
- flow rate
- resource consumption
Treatment Performance
• A table of general observations of treatment performance for each of the four technologies is presented in Appendix B.
Hot Air Vapor Stripping
• Treatment performance for a 15-ft. soil column:
VOC Removal Efficiency (%)
50
85
95-98
Minutes of Operation
90
120-150
225
• VOC removal efficiency for the 22-ft. soil column was approximately 88%.
• The mass of VOCs removed as estimated by off-gas sampling generally was consistent with the reduction in soil VOCs
estimated from pre-treatment and post-treatment sampling. These data indicated that VOCs were removed from the soil,
rather than being forced into surrounding undisturbed soil. This assessment was confirmed by the absence of significant
pressure or temperature effects on the unmixed region surrounding the treated columns.
• Off-gas temperatures increased from -25 to ~40°C after 225 minutes of treatment. Warming of the soil matrix was
demonstrated by using thermocouples. Seventy hours after completion of hot air injection, soil matrix temperatures
were 34°C and 37°C at depths of 3.5 and 9 feet, respectively. After 140 hours, temperatures remained elevated above
background.
• Mixing created a berm of soil of approximately 15% of the treated region above the treated volume for both vapor
stripping and peroxidation.
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PERFORMANCE
continued
The figure below, illustrates the relationship between the position of the auger and the concentration of VOCs in the off-gas.
The general decline in VOC concentrations with intermittent spikes suggested that VOCs were advectively removed from
the gas-filled voids surrounding soil matrix clods while the auger passed through. Diffusion of VOCs from the soil
matrix then replenished the gas-filled voids, which were later stripped during a subsequent pass of the auger.
u
D
83
o
200
> 150
100
50
•FID
Auger Depth ,! -
TE2
\ H fl-
• • I J *
:: t\ \ * .:! • i
f\ '.': i I :] / j -
! I H I ri H I -
II I n M Ml :
\J If !.''^1!V^
y r n r r •
60 120 180
Treatment time (min)
-2
-4
-6
-
-,
-12
-14
-16
I
240
Auger position and off-gas VOC concentration for hot air column TE2.
Ambient Air Vapor Stripping
• The treatment performance achieved with ambient air injection was similar but slightly lower than that achieved with
hot air. VOC removal efficiency for a 15-ft. soil column:
VOC Removal Efficiency (%)
50
85
92
Minutes of Operation
90
140-180
225
• Temperature of the off-gas increased gradually from 15°C. initially to 30°C. after 225 minutes of treatment. This gradual
increase in off-gas temperature is believed to be due to warming of the soil matrix. Thermocouples placed in the soil
revealed elevated temperatures of as much as 37°C. Elevated temperatures persisted for more than 94 hours after treat-
ment.
• The mass of VOCs removed as estimated by off-gas sampling generally was consistent with the reduction in soil VOCs
estimated from pre-treatment and post-treatment sampling. These data indicate that VOCs were removed from the soil,
rather than being forced into surrounding undisturbed soil.
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i PERFORMANCE
continued
The figure below illustrates the relationship between the position of the auger and the concentration of VOCs in the off-gas.
600
500
CQ
9
400
300
200
100
0
60 120
Treatment time (min)
180
240
Auger position and off-gas VOC concentration for ambient air column IE2.
Peroxidation Destruction
• VOC removal efficiency for a 15-ft. soil column averaged approximately 72% after 75 minutes of operation. This
removal efficiency is faster than that shown for vapor extraction.
• The apparent VOC treatment efficiency (total % removed) with peroxidation was below that achieved with both vapor
extraction processes. This could have been due to:
0 pre-treatment VOC concentrations were relatively low.
0 in situ mixing only occurred for a short period of time (i.e., 60 min.).
0 off-gas collection system capacity was too low during the peroxidation test (system dysfunctioned).
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PERFORMANCE
continued
The figure below illustrates the relationship between the position of the auger and the concentration of VOCs in the off-gas.
250
200
I
KJ
o
150
100
50
Auger Depth
2
0
-2
-4 £
-6
-8
-10
-12
-14
-16
$
!
0
60
120
Treatment time (min)
Auger position and off-gas VOC concentration for peroxidation column PI.
* Dunng the peroxidation test, the off-gas collection system malfunctioned yielding a flow rate of roughly 30% of the air
injection rate. This could have adversely affected the VOC treatment efficiency by altering the extraction of VOCs as
well as the distribution of the peroxide mist.
Solidification/Stabilization
• Dunng in situ mixing and grout injection, the concentrations of VOCs in the off-gas were at least an order of magnitude
loss than that obtained from the columns treated by vapor extraction/air injection. Because grout was applied before soil
mixing was initiated and because the grout application rate was rapid, little volatization of VOCs is believed to have
occurred as mixing proceeded.
• Total VOC concentrations in untreated soil ranged from 0.1 to over 500 mg/kg. Total VOCs in the uncured grout/soil
mixture were markedly lower than in untreated soil when compared by depth. Analytical problems with measurement
of VOCs in grout may be responsible for the uncertainty in the mass balance for the VOCs.
• Toxicity Concentration Leaching Procedure (TCLP) concentrations for regulated constituents were either not detected
or were well below EPA's regulatory limits. A few examples of the data collected are provided in Table 3, Appendix B.
• A comparison of physicochemical properties of untreated and solidified soil are provided in Appendix B.
0 The average bulk density of untreated soil (1.95 g/cm3) was greater than that of the soil/grout specimens (1.78 g/cm3).
The decrease in bulk density after solidification may be due to the initial high bulk density of a clay-rich sample,
which is reduced as a result of mixing. Also, the reduction in bulk density may be a result of entrapment/entrainment
of air in the grout during mixing.
0 The compressive strength values ranged from 390 to 5200 kPa (56 to 750 psig) and were inversely proportional to
depth. Samples from the upper part of the core appeared to be highly grouted, while the deepest sample (13-14 ft.)
appeared very fragile with a relatively small amount of grout material present. All values obtained, however, were
greater than the currently accepted guideline of at least 340 kPa (50 psig).
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PERFORMANCE
continued
0 The hydraulic conductivity (Ksat) of cured grout/soil samples was two orders of magnitude greater than that of the
untreated soil. This is probably due to disruption of the dense clay deposit as a result of mixing and increased porosity
within the grout/soil mixture due to incomplete filling of the pores with grout.
0 The pH of the grout/soil mixture (10.3-11.5) was significantly higher than that of the untreated soil (5.3-7.5), presum-
ably due to the high alkalinity of the cement-based grout. The stabilized soil/grout mixture should be more stable to
acid attack.
0 Total volatile solids analyses revealed values ranging from 1.2 to 8.0 wt% throughout the solidified soil, with the values
often lower than the corresponding value of the untreated soil column.
The strengths and hydraulic conductivities measured are probably in error due to the sampling technique. Other projects
using grout injection have demonstrated lower hydraulic conductivities and higher strengths.
As a result of mixing the dense clay soil and injecting grout, an above-ground berm was created above each solidified
column (approximately 1 meter high and equivalent to 30% v/v of the mixed region. The berms were eventually leveled
out and compacted with vibratory equipment.
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SECTION 4
TECHNOLOGY APPLICABILITY AND ALTERNATIVE TECHNOLOGIES
Technology Applicability
i
• In silu soil mixing is commonly used in the construction industry. In situ soil mixing for stabilization has been commonly
used at sites with soil contaminated with organics, but is also recognized as appropriate for metals-contaminated soils.
• ISESM with injection of hot air, ambient air, or hydrogen peroxide has been demonstrated to effectively remediate clay-
rich soils contaminated with VOCs in the unsaturated zone.
• ISESM is attractive for contaminated sites that contain low permeability soils that cannot be remediated using other
technologies, such as in situ bioremediation. However, it can also be used in more permeable materials.
* ISESM is attractive for relatively small sites.
• ISESM requires surface access at all locations where soils are contaminated.
Competing Technologies Ei
• ISESM as applied to sites like the X-231B site at Portsmouth competes with the following baseline technologies:
0 excavation followed by on-site or off-site storage and/or treatment,
0 in-place containment by capping and slurry wall emplacement.
Other technologies that were considered for demonstration at the X-231B site are listed below..
Soil treatment technology Technology description
In situ immobilization
Soil mixing by auger or jet system with addition of solidification/immobilization agent to solidify soil mass
and immobilize VOCs and other contaminants in place.
In situ hot-air and/or steam stripping
In site electrokinetics
In situ jet mixing and slurry reactor
Soil mixing by dual auger system with injection of hot air and/or steam to raise soil temperature and volatilize
VOCs.
Application of electrical energy to the soil mass in situ with induced mobility of water and ions toward a
capture electrode system.
In situ jet mixing with air or water to create an in-place slurry reactor that could be manipulated to achieve
physical, chemical, or biological processes for removal/degradation of VOCs.
In situ EM/RF heating
In situ application of electromagnetic or radiofrequency energy to heat the soil mass in place and volatilize
VOCs.
In site (ex situ) hydrogen peroxide
Injection of hydrogen peroxide during soil mixing by a dual auger system or by jetting, or application ex situ.
VOCs are chemically oxidized, physically stripped, and/or destroyed.
Ex situ thermal treatment
Ex silu immobilization
Excavated soil is processed by thermal treatment during which VOCs are volatilized, captured, and/or
destroyed.
Similar to in situ process, except excavated soil is treated above ground in a tank or container.
Technology Maturity
The 1992 technology demonstration brought together existing technologies into new configurations or systems so that
they could be applied in situ in low permeable media.
- For example, peroxidation destruction is commercially available for ex situ applications, however in situ treatment of
soils is novel.
- Solidification/stabilization is well established for inorganics, but some questions remained for its effectiveness on organics.
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SECTION 5
COST
Introduction
Information in this section was prepared from^data provided in various project reports from the actual demonstration and
from one of the vendors (Geo-Con). An independent cost analysis has not been performed.
Capital Costs
ISESM Actual Demonstration Costs (Jolley et al., 1991)
Task Description Estimated Cost
Project Management
Technical Task Plan Preparation
Permits and Plans
Procurement
Treatability Studies
Performance Monitoring
Site Preparation and Equipment Installation
Data Evaluation and Document Preparation
Labor
Travel (for equipment installation and monitoring
by the ORNL team
Supplies
Materials and Subcontracts
Treatability Studies
On-Site Demonstration
Plans and Permits
Site Preparation and Equipment Set-up
(included building a road to the site)
Demonstration (approximately 2 weeks of
soil mixing and treatment)
Demobilization and Site Restoration
(included recapping the site)
Vendor Subcontracts
Miscellaneous and Computer Support
Analytical Support, QA, Waste Management
Other (including G&A and GPS)
199,500
15,750
42,000
31,500
31,500
73,500
42,000
42,000
481,000
50,000
16,000
40,000
150,000
40,000
100,000
150,000
60,000
500,000
124,000
150,000
595,000
Total Actual Demonstration Costs
1,956,000
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COST
continued
Demonstration Cost Analysis
Costs for equipment operation during demonstration treatment of three regions to a depth of up to 15 ft. are estimated at
~$20K/day.
ISESM with a smaller auger blade would reduce equipment mobilization and demobilization costs.
For the demonstration, soil mixing costs were the same for each treatment process with minor cost variation between
processes based on required materials and equipment ($150 to $200/cy). Updated 1996 costs are estimated at $120-
175/cy or less. Further development of the technologies has shown that solidification is less costly than hot air injection.
0 Hot air vapor extraction costs were approximately 5% higher than for ambient air due to equipment; however, the
process obtained similar performance goals faster. Treatment times (drilling/injection time only) for hot air stripping,
deep hot air stripping and ambient air stripping were comparable and approximately 3 times slower than peroxidation
and 5 to 7 times slower than in situ immobilization.
0 Additional costs are associated with required materials for peroxide destruction and solidification/stabilization, but
both of these processes achieved treatment goals rapidly.
0 A technology selection table for the X-231B Site is located in Appendix C.
Vendor Cost Analysis E
Preliminary cost information is based on clean up of a contaminated site with the following characteristics:
- Area to be Treated: -29,000 sq. ft (-0.8 acres) [460-lOft or 720-8ft columns]
- Depth of Contamination: from ground surface to 25 ft deep
- Target Contaminants: VOCs
- Target Clean-up Goal: 90% destruction/removayimmobilization (total soil VOC concentration of less than 1 mg/kg)
Other assumptions include:
- Mixing with stabilization assumes use of Portland cement 15% by weight. Ten columns per day are grouted. No offgas
treatment is necessary for this application.
- Hot air injection assumes 5 columns per day. Each column is mixed for one hour.
- Jet mixing is calculated assuming using three-foot spacing on the columns. 3720 columns are required for treating the
area. Eight columns per day are completed. Cement must be added at 25% by weight. Two single stem rigs are used for
this application.
- No estimate for air monitoring, sampling, and testing is included.
- Security, utilities, grading, etc. are not included. Level D protective equipment is required and included.
- Cost for work at a government facility may be 10 to 50% higher.
- Costs are estimated by Geo-Con as of 1996. If the contract is written as performance based, additional mixing time
should be priced on an hourly or cost-plus basis.
Technique
Schedule
(Production Weeks)
8 ft 10 ft
Mobilization ($)
U.S. Department of Energy
126
Unit Costs ($/cy)
8 ft 10 ft.
Hot Air Injection 28.8 18.4
Stabilization 14.4 9.2
Jet Mixing 55.8
250,000
150,000
70,000
75 60
55 45
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SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations
Early and continuous communication with the regulatory community is essential when assessing and determining the
application of unproven or innovative technologies.
- At the Portsmouth Gaseous Diffusion Plant, the regulators were brought in to work with the site managers to select
options for closure of the X-231B site. This early involvement streamlined the process for regulatory approval of the
technology demonstration and also the later closure of the facility.
- Regulators in charge of ground water, surface water, RCRA, and the consent decree were all involved in the process.
The technology demonstration was conducted by modifying the closure plan for the X-231B facility. No RD&D Permit
was required.
The closure of the X-231B facility was approved by Ohio EPA, requiring a performance standard of 70% mass removal.
Actual mass removal was greater than 87% for the closure. A RCRA cap was placed on the surface.
Specific permits for this technology must be worked out with the appropriate regulators.
- Some type of air permit may be required because of the off-gas capture and treatment part of the system.
- An underground injection permit might be required if the treatment is occurring below the water table.
- CERCLA or RCRA permitting may be required.
- At federal facilities a NEPA review may be required.
1 Safety, Risks, Benefits, and Community Reaction ^•••^^^•••••i -^ • • " • EE=
Worker Safety
• Potential worker safety risks for all the processes include those associated with standard drilling operations and potential
exposure to VOCs and particulates in off-gas.
• Peroxide Injection: The hydrogen peroxide concentrations utilized were sufficiently low that it was not considered a
hazardous material and its handling was of limited health and safety concern. While hydrogen peroxide at 5% by weight
concentration is relatively harmless, it does require precautions in handling.
Community Safety
• ISESM with an operational off-gas treatment system does not produce any significant routine release of contaminants.
• No unusual or significant safety concerns are associated with transport of equipment, samples, waste, or other materials
associated with ISESM.
Environmental Impacts
• ISESM disturbs the ground surface during operations. But because the site is remediated rapidly, long term effects are minimal.
« Operation of the equipment creates moderate noise in the immediate vicinity.
Socioeconomic Impacts and Community Perception
• ISESM has a minimal economic or labor force impact.
• The general public has limited familiarity with ISESM.
Page 14
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U.S. Department of Energy
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SECTION 7
LESSONS LEARNED
Design Issues
• The equipment utilized for all process components was commercially available. However, the equipment may need to be
specially modified for a particular application.
• More recent experience suggests that an 8-ft. diameter auger may be optimum for this type of application.
• Hot Air Injection:
- The orifices in the 2-arm, 10-ft. diameter tool were reduced to 0.25 in. from the ambient air size of 0.5 in. to increase
the back pressure and enable maintenance of higher temperatures, thus encouraging further volatilization of contaminants.
- A compressor operator was required to manually control system airflow, temperature, and pressure. However, the system
has now been modified to be controlled automatically.
• Peroxidation:
- Peroxide must be delivered by tank truck or rail car to meet required treatment processing.
• Solidification/Stabilization:
- Laboratory treatability studies were performed to test the best grout formulation. The grout recommended contained
25% cement, 10% granular activated carbon, fly ash to increase fluidity and a retarder. Other more simple and less
costly formulations have been successfully used at other locations.
General observations regarding operation of each treatment process tested at the X-231B
Technology
Hot air vapor stripping
Ambient air vapor
stripping
Peroxidation
Solidification
Soil treatment
rateb
-15 c.y. per hour.
—15 c.y. per hour.
-45 c.y. per hour.
-45 c.y. per hour.
Operational
simplicity and
stability
Only requires an
air compressor.
Only requires an
air compressor.
Requires chemical
injection system
Requires grout injection
system.
Safety issues
Heavy equipment operation;
compressed hot air.
Heavy equipment operation;
compressed air.
Heavy equipment operation;
*V2; compressed air.
Heavy equipment operation;
grout handling equipment.
site.a
Secondary waste
generation
Off-gas and
decontamination fluids.
Off-gas and
decontamination fluids.
Off-gas, excess ^2^2'
and decontamination
fluids.
Off-gas, excess grout,
and decontamination
fluids.
* The information shown is preliminary and intended for general comparison only.
& Soil treatment rates (per equipment operating) were estimated assuming a process treatment efficiency of 70 to 95%.
• Injection of grout for solidification/stabilization required adjustments, including those made in the field. The grout
formulation was adjusted by:
- changing from powdered to granular activated carbon,
- adding fly ash to increase the consistency and fluidity of the grout,
- adding a retarder to provide a working time of 2 hours,
- adding water to the grout at the site to further increase workability.
Page 15
U.S. Department of Energy
128
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LESSONS LEARNED
continued
In situ solidification of contaminated soil materials was more complicated than originally anticipated. This was due in
part to the difficulty in effectively mixing the dense clay soils in situ and to delivering the proper volume of grout of the
appropriate formulation. There are likely to be infield adjustments to the grout formulation and injection volume after
working knowledge of the grout delivery system and the site conditions are acquired. Field experience since the demon-
stration has improved the process to make it more effective and efficient.
Generation of secondary liquid wastes, namely waste grout from the delivery trucks and from rinsing out the mixing
equipment, could be appreciable in the solidification process operation. An improved "grout-on-demand" system has
been developed to minimize waste.
I Technology Limitations/ Needs for Future Development i^^^^^»»
Potential enhancements to the ISESM approach include:
v more mobile and scaled down mixing equipment
0 more efficient coupling of treatment processes
Other technologies may be coupled to the ISESM process as a post-soil mixing enhancement:
v passive treatment processes for in situ treatment
0 soil vapor extraction
v bioremediation
Other reagent additives should be examined as alternatives:
0 other oxidants (e.g., permanganate, ozone)
0 reductants (e.g., zero-valence metals)
v sorbents (e.g., peat or zeolites).
Improvements in equipment and experience will eventually reduce costs further.
Page 16
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U.S. Department of Energy
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APPENDIX A
DEMONSTRATION SITE CHARACTERISTICS
Background
The DOE Portsmouth Gaseous Diffusion Plant is located approximately 70 miles south of Columbus in southern Ohio.
OHO
Location of the DOE Portsmouth Gaseous Diffusion Plant and the X-231B Unit
The X-231B waste management unit consists of two adjacent waste oil biodegradation areas. The X-231B Unit encom-
passes about 0.8 acres and was reportedly used from 1976 to 1983 for the treatment and disposal of waste oils and
degrcasing solvents, some containing uranium-235 C235!!) and technetium-99 ("Tc). TCE and other VOCs remained in
the soil and spread into the shallow ground water.
Page 17
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130
-------
APPENDIX A
continued
Site Characterization
Physical, chemical and biological properties of subsurface soil at the X-231B site as measured in samples collected in 1990.
Nominal depth and boring location
Characteristics
Shallow (7-ft depth)
SB01 SB02
SB03
SB01
Deep (17-ft depth)
SB02
SB03
Depth, ft
Particle size distribution:
Clay: <0.002 mm, wt%
Silt: 0.002-0.05 mm, wt%
Sand: 0.05-2.0 mm, wt%
Water content, dry wt %
Percent solids, wt%
PH
Total organic carbon, mg/kg
Kjeldahl nitrogen, mg/kg
Total phosphorus, mg/kg
Total sulfur, mg/kg
7.2
22.5
65.5
12.0
17.6
86.6
5.32
579
<500
66
24
6.2
na
na
na
na
na
na
na
na
na
na
6.2
25.0
67.0
8.0
19.0
81.0
5.96
1190
<500
66
17.2
14.0
64.0
22.0
23.5
81.8
7.40
245
<500
66
23
17.2
12.0
55.0
33.0
23.5
81.0
6.16
184
<500
73
30
17.2
15.0
39.0
46.0
22.0
81.2
7.01
472
<500
108
Exchangeable cations £
Calcium, mg/L
Magnesium, mg/L
Sodium, mg/L
Potassium, mg/L
Percent moistures, wt%
Liquid limits, wt%
Plastic limits, wt%
Plasticity indexes wt%
Total bacteria, CFU/g
Methanotrophs,
47
42
9.4
6.3
17.9
na
na
na
2.26E04
Detected
na
na
na
na
18.7
na
na
na
2.37E05
Detected
48
31
6.0
4.5
20.1
na
na
na
1.02E04
Detected
60
28
10.6
6.0
23.0
25.30
22.19
3.11
<1E02
Not
Detected
37
25
3.1
4.0
23.5
25.55
22.63
2.92
<1E02
Not
Detected
71
34
15.1
5.0
23.4
25.73
20.56
5.17
<1E02
Not
Detected
na Indicates analyses not performed.
a Results of analyses are expressed on a field moist soil weight basis unless otherwise indicated.
k Averages of duplicate analyses; coefficient of variation for duplicates was <5%.
£ Percent moisture {wet wt. %) analyses performed by Geraghty & Miller, Inc., Dublin, Ohio.
• Contaminants of Concern
0 Soil
- Thirteen VOCs were identified with the following being most prevalent and at the highest concentrations (i.e., several
hundred to several thousand micrograms per kilogram).
trichloroethylene (TCE)
1,1,1-trichloroethane (TCA)
1,1-dichloroethylene (1,1-DCE)
methylene chloride
- The highest concentrations were found in the unsaturated zone (~7-ft depth) near the center of the plot.
Low levels of 235U and "Tc are also present.
0 Ground water
The shallow ground water was also contaminated with some contaminants at levels well above drinking water standards.
Page 18
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U.S. Department of Energy
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APPENDIX A
continued
Contaminant Locations and Hydrogeologic Profiles i
i
Ground water underneath the X-231B unit occurs in two aquifer systems: the Minford/Gallia Members and the Berea
Sandstone. Existing site characterization data revealed that beneath the X-231B unit were fluvio-lacustrine silts and clays
(Minford Member of the Teays Formation) underlain by silty sand and gravel (Gallia Member). The Gallia Member
lies at a depth of approximately 25 ft and typically does not exceed 4 ft in thickness. Bedrock below the Gallia is the
Mississippian age Sunbury Shale. The Sunbury Shale is 10 to 12 ft thick, slightly fractured, and has very low permeability.
The water table in this area is approximately 10 to 14 ft below ground surface (bgs). Ground water flow occurs vertically
through the Minford Member into the Gallia Member where flow is predominantly horizontal to the southeast toward a
surface impoundment.
I— Contaminated Soil
TCE = 5-13.000 UOAO
U = l-ISOmg/kg
-
-
-
-
14
10
4
1C
Contaminated Groundwator
TCEupto 1400 na/L
U up to 39 |iQ/L
Subsurface characteristics beneath the X-231B Unit.
Thirty-six groundwater monitoring wells have been installed in the vicinity of the X-231B unit Twenty-five wells have
been installed and screened within the Gallia deposit, but only three wells have been screened in the overlying Minford.
Eight wells penetrate into the underlying bedrock (i.e., Sunbury or Berea).
The hydraulic conductivities of all the shallow units are low. Laboratory measurements revealed a saturated hydraulic
conductivity (K^,) of only 0.00023 feet per day (ft/d) for the Minford clay and 0.0043 ft/d for the Minford silt. Field
pumping tests yielded a substantially higher mean K^ for the Gallia deposit of 7.1 ft/d. The lower portion of the Minford
is in hydraulic continuity with the Gallia.
The permeability of the Sunbury Shale is believed to be very low. Although thin and slightly fractured, the Sunbury may
hydraulically isolate the underlying Berea from the overlying unconsolidated aquifer (i.e., Minford/Gallia).
Several VOCs (e.g., TCE and 1,1,1-TCA) are present throughout the Minford Member under the X-231B site from the
ground surface to approximately 25 ft bgs. These same contaminants are present in the shallow ground water underneath
and up to 750 ft downgradient from the X-231B Unit boundaries. The primary soil and ground water contaminant is
TCE, which is present in the ground water at levels above federal drinking water standards.
The Minford deposit beneath the X-231B Unit extends from the ground surface to approximately 22- to 24-ft depth. The
Minford is comprised of an upper zone (top 12 ft or so) that is finer textured than the lower zone. Intensive sampling and
analysis of the Minford deposit was conducted to delineate the contaminant distribution throughout the deposit to enable
development of the treatment locations for the field test. Analysis of the results of this work revealed that approximately
78% of the VOCs are located in the upper 12 ft, above the water table. As a result, the field test was designed to focus on
treatment of the unsaturated portion of the Minford deposit (i.e. the upper 15 ft). In addition, a single test was conducted
to a depth of approximately 22 ft to provide some operational information for treatment of the lower Minford deposit,
located below the water table.
Page 19
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132
-------
APPENDIX B
TECHNOLOGY DESCRIPTION/PERFORMANCE DETAIL1*
Operating Parameters
Auger rotation speed
Auger vertical movement rate
Mixed region diameter
Mixed region depth
Mixed region volume
Air delivery rate
Air exchange in soil column
Air temperature at the source
Air pressure at the source
Shroud vacuum
Peroxide injection rate
Peroxide injection volume
Peroxide concentration
Grout injection rate
Off-gas flow rate
Treatment cycles
0 to 7 ft zone
7 to 15 ft zone
0 to 15 ft zone
Treatment time per column
approximately
cfm cubic feet per minute
gpm gallons per minute
in H2O inches of water
psig pounds/square inch (gauge)
vol% per cent by volume
Units
rpm
fpm
ft
ft
cf
cfm
RV/min
op
psig
in. H2O
gpm
voL/vol.
wt%
vol.%
cfm
down/up
down/up
down/up
min
Hot Air Hot Air
Stripping Stripping -
Deep
5 to 10 5 to 10
1 1
10 10
15 22
1180 1730
1000-1400 1000-1400
0.8 - 1.2 0.6 - 0.8
250 250
180 180
-5 ~5
-
-
-
-
-
8 8
4 4
225 225
cf cubic feet
fpm feet per minute
0 degrees Fahrenheit
min. minutes
RV/min reactor volumes/minute
wt% per cent by weight
Ambient Air
Stripping
5 to 10
1
10
15
1180
1000-1400
0.8 - 1.2
90
100
~ 5
-
-
-
-
-
8
4
225
Peroxidation
Destruction
5 to 10
1
10
15
1180
800
initially,
reduced to 300
-
90
80
-
7.5
ave. of 0.07
5
-
-
2
1
75
-i
Solidification
Stabilization
5 to 10
Ito3
10
15
-
0
_
.
-
~ 5
-
-
-
30
100-120
3 to 4
30 to 45
Page 20
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U.S. Department of Energy
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APPENDIX B
continued
Treatment Performance: General Observations i
General Observations for Each Treatment Process Tested at the X-231B Site.
Technology
and
components
Hot Air Vapor
Stripping. An air
compressor to deliver
-1400cfmof250°F
air through a hollow
kclly bar via jets in a
10 ft. auger.
Ambient Air Vapor
Stripping. An air
compressor to deliver
-1400cfmof995% mass removal
after 3.75 hr of
treatment in a 10 ft.
diameter by 15 ft.
deep column.
>90% mass removal
after 3.75 hr of
treatment in a 10ft.
diameter by 15ft.
deep column.
>70% mass removal
after 1 hr of treatment
in a 10 ft. diameter by
15 ft. deep column.
>90% apparent
capture of VOCs in
preset grout/soil mix
after 1 hr of treatment
in a 10 ft. diameter by
15 ft. deep column.
Effect on
non-VOC
contaminants
Limited if any; stimu-
lation of biological
activity and possible
degradation of
SVOCs
Limited if any; stimu-
lation of biological
activity and possible
degradation of
SVOCs
Increased binding of
metals. Preoxidation
of SVOCs for
biodegradation.
Encapsulation and
stabilization of metals
in grout.
Effect on
soil
properties
Disrupts natural soil
structure. Injection
of hot air stimulated
some increased
biological activity.
Disrupts natural soil
structure. Injection of
air stimulates marked-
ly increased biological
activity.
Mixing disrupts natur-
al soil structure.
Injection of H202 does
not "sterilize" soil.
H202 can reduce soil
permeability of clays.
Mixing disrupts
natural soil structure.
Injection of grout
reduces permeability
significantly.
Effect on
unmixed adja-
cent soil
Limited impact on
soil gas concentra-
tions or pressure.
Limited impact on
soil gas concentra-
tions or pressure.
Limited impact on
soil gas concentra-
tions or pressure.
Limited impact on
soil gas concentra-
tions or pressure.
Treatment Performance: Post-demonstration Soil Chemical Analyses
Results of selected TCLP analyses of grouted soil after in situ solidification.
Cores collected at 15 months Post-demonstration grout soil samples
(me/L) a (mg/L) b
Target analyte
Carbon Tctrachloride
Benzene
1,2-Dichloroc thane
Trichlorocthylcne
Barium
Lead
Uranium
4-5 ft depth
< 0.025
< 0.025
< 0.025
0.08
9.4
<0.05
< 0.0004
8-9 ft depth
< 0.025
< 0.025
< 0.025
< 0.025
2.9
<0.05
< 0.0004
4-5 ft depth
<0.15
<0.09
<0.10
<0.22
8-9 ft depth
<0.15
<0.09
<0.10
<0.22
TCLP Limits
(mg/L)
0.5
0.5
0.5
0.5
100.0
5.0
* Samples collected 15 months after in situ solidification in August 1993 and analyzed at ORNL Analytical Chemistry Division.
b Samples collected inuncdiately following in situ solidification in May 1992 and analyzed at the Clemson Technical Center, Clemson, South Carolina.
Page 21
U.S. Department of Energy
134
-------
APPENDIX B
continued
• Treatment Performance: Physicochemical Properties of Soil, Pre-and Post-Demonstration
Physicochemical properties of the untreated and solidified X-231B soil.
Sample description
Untreated
control core
S/S core
Sample
depth
(m)
0.3-0.6
1.2-1.5
2.4-2.7
3.9-4.2
0.3-0.6
1.2-1.5
2.4-2.7
3.9-4.2
Water
content
(wt%) a
20.5 £
16.9 £
18.4 £
16.5 £
19
23.5
19
13.6
Bulk
density
(g/cm3)
2.15
1.75
1.73£
1.66£
1.72
2.00£
Compressive
strength (kPa)
5200 d
3500
2600
390
Hydraulic
conductivity k
(cm/sec)
8.08xlO-8
8.09x10-8
8.88xlO-6
7.75xlO-«
a Analyses performed at 60°C.
b All values represent at a minimum, the average of 6 replicate analyses. Data reported at 25°C per ASTM D5084. Permeant fluid = 0.005M CaSO/j.
£ Average of analyses of two samples.
d Sample taken at the 1-m depth.
Page 22
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U.S. Department of Energy
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APPENDIX C
TECHNOLOGY SELECTION DETAIL
Technology Selection
Selection of the most promising technologies for demonstration at X-231B was accomplished by a ration ranking process.
The approach enabled rigorous evaluation of each technology and provided results regarding implementation, operation and
maintenance, performance and cost. The following table summarizes key information from this process for comparison of
technologies.
Technology
Estimated Time for
Installation & Operation
Processing Rates
Minimization of
Full-scale
Remediation Costsa
In situ immobilization
In situ hot air/steam stripping
In situ electrokinetics
In situ jet mixing and slurry reactor
In situ electromagnetic or
radiofrequcncy energy heating
In situ (ex situ) hydrogen peroxide
Ex situ thermal desorption
Ex situ immobilization
1 month
rapid
additional research required
prior to VOC application
1 month
5 months (3 mo. installation,
2 mo. operation)
Installation about 1 week,
operation about 1 month
5 months to 2 years
1 months
1000 cy/d
3 to 10 cy/hr
N/Ab
N/Ab
20 cy/d for demo
200 tons/d full scale
100 cy/d
100 to 200 tons/d full scale
10,000 to 20,000 cf/d
54
50
38
46
39
39
34
49
* Score listed is the result from the ranking process. The higher the score the greater the ability of the technology to minimize full-scale remediation costs.
k Not done to remove VOCs at the time of this demonstration.
Page 23
U.S. Department of Energy
136
-------
APPENDIX D
REFERENCES
1. Chemical Waste Management, Inc. 1992. Final project report for X-231B In Situ Stabilization Demonstration Project at
the Portsmouth Gaseous Diffusion Plant, Piketon, Ohio. Prepared by Chemical Waste Management, Inc., Columbia, SC
for Martin Marietta Energy Systems, Inc., Oak Ridge National Laboratory, Oak Ridge, TN, 37831
2. Advanced Sciences, Inc. 1988. Sampling Report for Piketon Oil Diode gradation Plot Project. ASI Project Number 661,
Task JO. Prepared by Advanced Sciences, Inc. for Martin Marietta Energy Systems, Inc.
3. Morrison Knudsen Corporation. 1989. X-231B Oil Biodegradation Plot Closure Options Study, 1989. Report POEF-Z-
4198. Prepared by Morrison Knudsen Corporation Environmental Services Group, Cleveland, Ohio for the Portsmouth
Gaseous Diffusion Plant, operated by Martin Marietta Energy Services, Inc. for the U.S. Department of Energy.
4. Siegrist, R.L., Morris, M.I., Donaldson, T.L., Palumbo, A.V., Herbes, S.E., Jenkins, R.A., Morrissey, C.M., and Harris,
M.T. 1993. The X-231B Technology Demonstration for In Situ Treatment of Contaminated Soils: Technology Evaluation
and Screening. Oak Ridge National Laboratory Report, ORNL/TM-12257.
5. Davenport, D. T., D. J. Georgopoulos, R. L. Siegrist, M. I. Morris, and O. M. West. 1993. Technology Demonstration,
Assessment, and Application for a RCRA Closure, Observations and Lessons Learned in the Process. Presented at
WM93, February 28 - March 4, 1993, Tucson, AZ.
6. Morris, M. L, R. L. Siegrist, and D. T. Davenport. 1993. Environmental Technology Demonstrations at U. S. DOE
Facilities: Observations Regarding the Current Process and Methods for Improvement. Presented at WM93,
February 28 - March 4, 1993, Tucson, AZ.
7. Reyes, O. M., R. L. Siegrist, D. D. Gates, H. L. Jennings, A. J. Lucero, and R. A. Jenkins. 1992. Technical Workplan
for ORNL Treatability Studies. Interim Report ERP-TI/91-628, Oak Ridge National Laboratory, Oak Ridge, TN.
8. U.S. Department of Energy. 1991. Environmental Assessment for the X-231B Soil Decontamination Technology Demon-
stration at the Portsmouth Gaseous Diffusion Plant, Piketon, Ohio. U.S. Department of Energy Report DOE/EA-0607.
9. Muhr, C.A., D.A. Pickering, R.L. Siegrist, TJ. Mitchell, R.A. Jenkins, and D.W. Greene. 1991. Technical Workplan for
Sampling for Characterization and Treatability Studies. Internal report ERP-TI/91-627, Oak Ridge National
Laboratory, Oak Ridge, TN, 37831.
10. Siegrist, R.L., M.I. Morris, D.A. Pickering, S.E. Herbes, O.M. Reyes, T.J. Mitchell, R.A. Jenkins, and C.A. Muhr. 1992.
ORNL Technical Workplan for Field Demonstration, Testing, and Evaluation Studies. Internal report ERP-TT/92-223,
Oak Ridge National Laboratory, Oak Ridge, TN, 37831.
11. West, O.R., Siegrist, R.L., Mitchell, T.J., Pickering, D.A., et al. 1993. The X-231B Technology Demonstration for In
Situ Treatment of Contaminated Soils: Contaminant Characterization and Three-Dimensional Spatial Modeling.
Oak Ridge National Laboratory Report, ORNL/TM-12258.
12. Siegrist, R.L. et al. 1991. Project Description for In Situ Soil Mixing and Physicochemical Treatment Processes for
Trichloroethylene and Other VOCs in Wet, Slowly Permeable Soils - Phase 2 Technology Demonstration. Oak Ridge
National Laboratory, Oak Ridge, TN 37831.
13. West, O. R., R. L. Siegrist, J. S. Gierke, S. W. Schmunk, A. J. Lucero, and H. L. Jennings. 1995. "In Situ Mixed
Region Vapor Stripping in Low Permeability Media. 1. Process Features and Laboratory Experiments." Environmental
Science and Technology, 29(9):2191-2197.
14. Siegrist, R. L., O. R. West, M. I. Morris, D. A. Pickering, D. W. Greene, C. A. Muhr, D. T. Davenport, and J. S. Gierke.
1995. "In Situ Mixed Region Vapor Stripping in Low Permeability Media. 2. Full-Scale Field Experiments."
Environmental Science and Technology, 29(9):2198-2207.
Page 24
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U.S. Department of Energy
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APPENDIX D
continued
15. Gicrke, J. S., C. Wang, O. R. West, and R. L, Siegrist. 1995. "In Situ Mixed Region Vapor Stripping in Low
Permeability Media. 3. Modeling of Field Tests." Environmental Science and Technology, 29(9):2208-2216.
16. Gcraghty & Miller, Inc. 1989. Ground Water Quality Assessment ofFourRCRA Units Portsmouth Gaseous Diffusion
Plant, Piketon, Ohio. Prepared for the Portsmouth Gaseous Diffusion Plant, managed by Martin Marietta Energy
Systems, Inc., for the U. S. Department of Energy.
17. -. 1990. International Waste Technologies/Geo-Con In Situ Stabilization/Solidification. EPA/540/A5-89/004.
18 Rust Geotech. 1995. Commercial Environmental Cleanup - The Products and Services Directory. DOE/ID/12584-230.
GJPO-120.
19. Jolley, R.L., M.I. Morris, and S.P.N. Singh. 1991. Guidance Manual for Conducting Technology Demonstration
Activities. Oak Ridge National Laboratory Report, ORNL/TM-11848.
Page 25
U.S. Department of Energy
138
-------
This report was prepared by:
Colorado Center
for
Environmental Management
999 18th Street, Suite 2750
Denver, Colorado 80202
Contact: Dawn Kaback
(303) 297-0180 Ext. 111
in conjunction with:
Oak Ridge National Laboratory
P.O. Box 2003
Oak Ridge, Tennessee 37831
Contact: Kathryn Lowe
(303) 966-3430
Assistance was provided by
Millgard Environmental Corporation
Geo-Con
139
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-------
Flameless Thermal Oxidation at the M Area,
Savannah River Site, Aiken, South Carolina, in Cooperation
With the U.S. Department of Energy Oak Ridge Operations
-------
Case Study Abstract
Flameless Thermal Oxidation at the M Area,
Savannah River Site, Aiken, South Carolina, in Cooperation With
the U.S. Department of Energy Oak Ridge Operations
Site Name:
U.S. Department of Energy (DOE),
Savannah River Site,
M Area Process Sewer/Integrated
Demonstration Site
Location:
, South Carolina
Contaminants:
Chlorinated Aliphatics
- Trichloroethene (TCE), tetrachloroethene
(PCE), and 1,1,1-trichloroethane (TCA)
- TCE concentrations in the off-gas ranged
from 157 to 291 ppm, PCE from 243 to 737
ppm, and TCA from 12 to 21 ppm.
Period of Operation:
April to May 1995
Cleanup Type:
Field demonstration
Vendor:
Bob Wilbourn
Thcrmatrix, Inc.
(615) 539-9603
Technical Information:
Tim Jarosch, Prin. Inv., WSRC,
(803) 725-5189
Richard Machanoff, HAZWRAP,
(615) 435-3173
SIC Code:
9711 (National Security)
3355 (Aluminum Forming)
3471 (Metal Finishing)
Technology:
Post-Treatment (Air) - Flameless Thermal
Oxidation
- Flameless Thermal Oxidizer (FTO) is a
commercial technology available from
Thermatrix, Inc.
- FTO uses a heated packed bed reactor
typically filled with saddle- and spherical-
shaped inert ceramic pieces to destroy
chlorinated and non-chlorinated volatile
organic compounds (VOCs) in vapors
extracted by a Soil Vapor Extraction (SVE)
system.
- Designed to oxidize off-gases without
forming PICs or HAPs; not viewed as an
incineration technology.
Cleanup Authority:
State: Air discharge permits
for the Savannah River
demonstration site are in place
with the South Carolina
Department of Health and
Environmental Control
(SCDHEC)
Point of Contact:
Jef Walker, DOE,
(301) 903-7966
Jim Wright, DOE,
(803) 725-5608
Waste Source:
Surface impoundment (unlined
settling basin)
Type/Quantity of Media Treated:
Off-gases (extracted vapors)
- Information not provided on quantity treated
Purpose/Significance of
Application:
FTO was demonstrated as an
alternative technology for treatment
of extracted vapors during an SVE
application to oxidize off-gases
without forming PICs or HAPs.
Regulatory Requirements/Cleanup Goals: ,
- The Savannah River site maintains air discharge pennits for in situ remediation demonstrations associated with VOCs
in non-arid soils and ground water.
- No specific regulatory requirements or cleanup goals were identified for the FTO demonstration.
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Case Study Abstract
Flameless Thermal Oxidation at the M Area,
Savannah River Site, Aiken, South Carolina in Cooperation With
the U.S. Department of Energy Oak Ridge Operations (Continued)
Results:
This demonstration was evaluated in terms of destruction and removal efficiency (DRE) for specific VOCs and total
chlorinated VOCs (CVOCs).
- The FTO unit achieved > 99.995% DRE for PCE and > 99.95% for TCE and total CVOCs during a 22-day
continuous operation testing stage.
- The FTO unit achieved > 99.995% DRE for total CVOCs during a 2.5 day testing period where the influent stream
was spiked with 950 to 3060 ppm CVOC.
Cost Factors:
- Capital cost for the FTO unit used in the demonstration was $50,000 (for an electrically heated, 5 scfm unit without an
integrated caustic scrubber).
- Total operating costs for FTO technology were estimated at $0.72 per pound of CVOC destroyed, including costs for
capital recovery, energy, labor, and maintenance.
- No additional details provided on components of capital or operating costs; however, the authors report that FTO
costs less per pound of CVOC destroyed than competing technologies such as thermal catalytic technologies.
Description:
From 1958 to 1985, Savannah River Area M conducted manufacturing operations including aluminum forming and metal
finishing. Process wastewater from these operations containing solvents (TCE, PCE, and TCA) was discharged to an
unlined settling basin at Savannah River, which lead to contamination of ground water and vadose zone soils.
Treatment of vadose zone soils has been the subject of several demonstrations (e.g., in situ air stripping), including this
investigation of the technical and economic performance of off-gas treatment technologies.
Flameless thermal oxidation (FTO) is a commercial technology used in a demonstration at Savannah River Area M to
treat chlorinated VOCs in off-gasses extracted using a SVE system. FTO uses a heated packed bed reactor typically
filled with saddle- and spherical-shaped inert ceramic pieces to destroy chlorinated and non-chlorinated VOCs in vapors
extracted by a SVE system. The demonstration was based on pumping from one horizontal SVE well at a flow rate of 5
scfm, and the thermal reaction zone in the FTO was maintained at 1400 to 1700°F. A caustic scrubber was not included
in this demonstration because of the relatively small quantity of HC1 produced.
This demonstration was evaluated in terms of destruction and removal efficiency (DRE) for specific VOCs and total
chlorinated VOCs (CVOCs). The FTO unit achieved >99.99% DRE for PCE, and >99.995% DRE for total CVOCs
during a testing period where the influent stream was spiked with CVOC. During the continuous and spike testing
phases, no PICs or HAPs were detected in the FTO effluent.
143
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SECTION
SUMMARY
Technology Description
The Flameless Thermal Oxidizer (FTO) is a commercial technology offered by Thermatrix, Inc. The FTO
has been demonstrated to be an effective destructive technology for process and waste stream off-gas
treatment of volatile organic compounds (VOCs), and in the treatment of VOC and chlorinated volatile
organic compounds (CVOCs) off-gases generated during site remediation using either baseline or
innovative in situ environmental technologies. The FTO process efficiently converts VOCs and CVOCs to
carbon dioxide, water, and hydrogen chloride. When FTO is coupled with a baseline technology, such as
soil vapor extraction (SVE), an efficient in situ soil remediation system is produced.
The innovation is in using a simple, reliable, scalable, and robust technology for the destruction of VOC
and CVOC off-gases based on a design that generates a uniform thermal reaction zone that prevents
flame propagation and efficiently oxidizes off-gases without forming products of incomplete combustion
(PICs).
Outlet
Inlet
f f t r»
Porous Inert Media
(loose packed ceramic)
1*. • s* v»jf"
fe«* ' > * »»*.,,
t , *
M
The FTO provides destruction and removal efficiencies (DREs) in excess of 99.99% for hydrocarbons
and CVOCs.
The FTO unit yields extremely low NOx formation (typically < 2 ppmv) and extremely low CO
formation (typically below the limits of detection) as measured from the effluent stream.
The FTO can compensate for operations of low flow rates with low concentrations to high flow rates
with high concentrations without affecting ORE.
The FTO unit operates with a low pressure drop across the FTO reactor, typically < 3 inches of water.
The FTO unit has been applied to gas flow rates ranging from 1 scfm to 6500 scfm.
The Thermatrix FTO offers low capital and operating costs.
The FTO is engineered to operate safely and includes the following safety design features:
- operations below lower explosion limits,
- inherent flame arrester (ceramic matrix), and
- large heat sink (ceramic matrix) to accommodate process fluctuations.
The FTO has been permitted for many hazardous air pollutant (HAP) control applications.
U.S. Department of Energy
144
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Technology Status i
A full-scale demonstration was conducted at the Savannah River Integrated Demonstration site where
DOE has tested a number of off-gas treatment technologies.
U.S. Department of Energy
Savannah River Site
M Area Process Sewer/Integrated Demonstration Site
Aiken, South Carolina
April to May 1995
• The demonstration was conducted by the Savannah River Technology Center by a scientific team that
had evaluated and analyzed technical and economic performance of other off-gas treatment
technologies.
The demonstration site was located at one of the source areas within the 1-mile2 VOC groundwater
plume. Before the application of FTO coupled to SVE, the trichloroethylene (TCE), tetrachloroethylene
(PCE), and 1,1,1-trichloroethane (TCA) concentrations in the off-gas ranged from 157 to 291 ppm, 243 to
737 ppm, and 12 to 21 ppm, respectively. The site conditions are described in more detail in Appendix A.
Key Results
• In 22 days of continuous operation treating DOE Savannah River Site wellhead SVE effluent, a total of
11.17 Kg of total CVOC was destroyed with no identifiable products of incomplete oxidation observed
in any outlet sample.
• The Thermatrix unit successfully met and exceeded the 99.99% ORE for PCE at operating conditions
of 1600°Fand5scfm.
• All of the analyzed outlet samples were found to be below the analytical methodology detection limit
with respect to any of the primary CVOCs in the inlet stream.
• The concentrations of TCE and TCA in the inlet feeding from the well were too low to enable a ORE
measurement of > 99.99%; however, PCE is the major contaminant and typically the most difficult to
destroy using thermal techniques and, therefore, the DRE for PCE is viewed as representative of the
technology's true performance.
• In tests in which the feed stream was spiked with PCE, TCE, and TCA, the respective DREs were
measured at > 99.995%, > 99.99%, and approaching 99.99%, respectively. These values represent
the minimum DREs attained as all of the outlet samples were determined to be below the limit of
detection of the analytical methodology with respect to PCE, TCE, and TCA.
The FTO is commercially available through Thermatrix, Inc.; more than 20 units have been placed in
operation.
Contacts
Technical
Tim Jarosch, Principal Investigator, WSRC, (803) 725-5189
Richard Machanoff, Project Manager, HAZWRAP, (615) 435-3173
Management
Jef Walker, DOE EM-50 Program Manager, (301) 903-7966
Jim Wright, DOE Plume Focus Manager (803) 725-5608
Applications
Bob Wilbourn, Thermatrix, Inc., (615) 539-9603
145
U.S. Department of Energy
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SECTION 2
TECHNOLOGY DESCRIPTION
Overall Program Schematic
Inlet
Top View
Porous Inert
Media
Reaction
Front
Outlet
Inlet
Outlet
The Thermatrix FTO technology achieves uniform thermal oxidation of CVOCs and VOCs using a
heated packed-bed reactor typically filled with saddle- and spherical-shaped inert ceramic pieces.
The oxidation of organic compounds occurs in a uniform thermal reaction zone contained in the
packed bed of an inert ceramic matrix typically maintained at temperatures of 16uO°-1850° F.
The FTO design eliminates problems of temperature gradients, mixing, and resulting formation of PIC
and HAP.
The large thermal mass of the inert ceramic matrix enables it to store or release large amounts of
heat without rapid changes in temperature and provides flame suppression within the FTO reactor.
U.S. Department of Energy
146
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Demonstration
of Thermatrix
Technology
Aboveground System
WELL FLOW
FAIR
K.EED
i^
KNOCKOUT
POT
ill DRAIN
ROTARY LOK BLOWER
GAUGE
(]_) * IEKPERAIURC SENSOR
The source of the air/CVOC feed gas used in this demonstration was well AMH-4, one of seven
horizontal wells at the DOE SRS Demonstration Site.
The well was pumped with a small SVE unit capable of providing up to 10 scfm of flow.
The SVE system removed contaminant vapors and air from the subsurface; the vapors were passed
through a knockout pot to remove any entrained moisture.
147
U.S. Department of Energy
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The effluent from the SVE unit was fed directly to the inlet of a Thermatrix ES - 300H for treatment by
FTO with the SVE pump providing the motive force for the FTO feed stream.
CVOCs extracted from the soil by the SVE unit were oxidized in the Thermatrix oxidizer to form CO2,
H2O, and HCI.
The small scale of the demonstration permitted operation of the FTO without a caustic scrubber to
remove the HCI produced. In large-scale operations, the FTO effluent stream would be coupled with
a caustic scrubber.
U.S. Department of Energy
148
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SECTION 3
PERFORMANCE
Demonstration Plan
Performance of the technology has been assessed using information from the demonstration at SRS.
Three operational modes were tested during the demonstration:
Preliminary testing to determine optimal parameters for continuous operation (2.5 days)
Continuous operation testing stage (22 days)
Spike testing stage to increase the level of detection for determining ORE (2 days)
Treatment Performance
Summary
• The FTO successfully destroyed a CVOC air/gas mixture generated by SVE at the SRS Demon-
stration Site.
• The FTO unit achieved > 99.995% ORE for PCE and >99.95% ORE for TCE and total CVOC during
the continuous testing phase of the 22-day demonstration.
• During the demonstration, concentrations of PCE, TCE, and total CVOC in the FTO influent
decreased as a result of the continual removal of CVOCs from the subsurface by SVE. Lowered
concentrations of the FTO influent limited the minimal concentrations of CVOC that could be detected
in the FTO effluent.
• Over a 2.5-day period, the FTO influent stream was spiked with 950 to 3060 ppmv total CVOC in an
effort to extend the detection limits of FTO effluent, and DREs were measured at >99.995% for total
CVOC.
• Throughout the continuous testing stage and the spike test phase, no PICs or HAPs were detected in
the FTO effluent.
• During the continuous testing stage and the spike test phase of the demonstration 11.27 and 1.5 kg
total CVOC were destroyed, respectively.
• The only downtime experienced over the course of testing was to change the oil in the rotary pump of
the mini-SVE every 10 days (approximately 1 hour per oil change).
Key System Parameters
• The FTO was operated in a continuous mode at 5 scfm and 1600° F for 22 days.
• The FTO operated with minimal attention and required no maintenance or repairs for the 6 weeks of
the demonstration.
• CVOCs were extracted from the subsurface from a horizontal well by means of a mini-SVE unit and
supplied to the FTO at 5 scfm.
• The FTO influent CVOC concentrations during the preliminary and continuous demonstration
operation varied from 400 to 1000 ppmv with typical equilibrium concentrations of 400 to 600 ppmv.
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U.S. Department of Energy
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• The FTO was electrically heated, though methane or propane would be the heat source for large-
scale remediation with a >100 scfm throughput.
• The demonstration site air permit did not require caustic scrubbing of the HCI released from the
treatment of CVOCs by the FTO technology, but a caustic scrubber would be required during full-
scale site remediation.
Amount of VOCs Destroyed
• During the preliminary testing stage of the demonstration, the optimal operating conditions for the FTO
were verified at 5 scfm and 1600°F and >1 .5 Kg total CVOC were destroyed during this phase of the
demonstration. The parameters tested are described in the table below.
• During 22 days of continuous operation, the FTO destroyed 1 1 .17 Kg of CVOCs.
• The vapor contaminants consisted primarily of PCE (70.5%), TCE (28.2%), and 1,1,1 -trichloroethane
* The FTO successfully destroyed the targeted chlorinated organics with a DRE >99.99% at its design
conditions of 5 scfm and 1600° F.
• The spike testing stage of the demonstration confirmed that the FTO could accommodate high CVOC
concentration gas streams and >1 .5 Kg total CVOC were destroyed during this stage of the
demonstration at DRE > 99.995%.
Calculated Destruction Removal Efficiencies (DREs) During Preliminary Testing
Operating Conditions
(time on stream")
1600°F&5scfm
(30 min)
1600°F&5scfm
(2.5 hrs)
1600°F&7scfm
(1 hr15 min)
1500°F&5scfm
(12 hrs)
1700°F & 5 scfm
(1 hr15min)
1400°F&5scfm
(2 hrs)
1400°F&5scfm
(14 hrs)
1400°F&5scfm
(19 hrs)
1500°F&3.5cfm
(1 hMSmin)
1500°F & 3.5 cfm
(3 hrs)
PCE DRE
9.99932E-01"
9.99929E-01b
9.99700E-01
9.871 57E-01
9.99971 E-01C
9.98467E-01
9.91007E-01
5.29836E-01
9.99797E-01"
9.99794E-01b
CVOC DRE
9.99382E-01
9.99352E-01
9.99087E-01
9.90782E-01
9.99705E-01
9.98754E-01
9.93651 E-01
6.16475E-01
9.98387E-01
9.98363E-01
a = time on stream from establishment of current operating parameters
b = ND, normal split
c « < MDL, minimum split
d = < MDL, normal split
U.S. Department of Energy
150
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AMH-4 Well Concentrations (FTO Inlet) vs Time During Demonstration
1200
4/10/950:00 4/15/950:00 4/20/950:00 4/25/950:00 4/30/950:00 5/5/950:00 5/10/950:00
Date & Time
Results of Spike Tests
First Day
No Sparge0
Sparge-1
Sparge-2
Sparge-3
No Sparge
Sparge-1
Sparge-2"
Conc'n (ppmv)
Total
PCE TCE TCA CVOC
307
448
551
1037
293
946
1915
133
242
279
607
126
490
778
125
204
456
280
386
447
954
1126
2182
432
1742
3087
Calc. ORE*
Total
PCE TCE TCA CVOC"
.999967
NC
.999982
.999990
.999966
.999989
.999995
.999699
NC
.999856
.999934
.999684
.999918
.999949
NC
.999804
.999912
.999857
.999896
.999886
NC
.999913
.999957
.9999881
.999948
.999971
NC = no outlet sample taken . .
a = outlet analysis for all primary constituents were nondetect. Reported DREs are minimum values (i.e., DRE>listed
value).
b = total CVOC primary constituents listed in table.
c = sparge is the addition of concentrated CVOC to the FTO influent
d = well flow off, total flow is ambient air + sparge flow.
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U.S. Department of Energy
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SECTION 4
TECHNOLOGY APPLICABILITY AND
ALTERNATIVE TECHNOLOGIES
Technology Applicability!
FTO is an off-gas treatment technology that can be readily coupled with baseline or innovative
remediation technologies or manufacturing processes where VOC and CVOC vapors are generated.
FTO has been demonstrated to effectively destroy VOCs and CVOCs in off-gases from many
sources, including:
CVOC off-gas from SVE of subsurface contaminated with PCE, TCE, and TCA;
VOC and petroleum vapors including the BTEX class of compounds from soil remediation, oil
recycle, and manufacturing processes;
treatment of pulp plant noncondensable gases containing sulfur compounds;
treatment of methylene chloride emissions generated during pesticide production; and
treatment of wastewater from a chemical company containing butyl chloride, benzyl chloride, ethyl
chloride, and toluene.
Competing Technologies
Baseline technologies for treatment of CVOC and VOC off-gas from remediation processes include:
thermal oxidation,
catalytic thermal oxidation, and
adsorption/recovery.
On a performance level, the flameiess thermal oxidation technology can readily exceed destruction or
removal efficiencies achieved by either thermal catalytic techniques or by adsorption/recovery
systems.
Technology Maturity
The FTO is a mature technology that has been successfully commercialized by Thermatrix, Inc.
The FTO has been successfully installed and is currently operating more than 30 units in the private
sector in 16 states, France, and the United Kingdom.
The FTO technology can be scaled and tailored to site specific conditions and can be readily
incorporated into existing treatment trains or manufacturing processes.
Other innovative technologies are currently under development by DOE, including (1) activated carbon
by steam reforming, (2) gas-phase bioreactor, (3) membrane separation; (4) high-energy corona,
(5) silent discharge plasma, (6) xenon flashlamps, (7) pulsed combustion, and (8) solvent recycle.
FTO is a destructive technology that differs from thermal oxidation by preventing formation of PIC and
HAPs during the destruction process.
U.S. Department of Energy
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SECTION 5
COST
Introduction
Information in this section was prepared from data provided to the Hazardous Waste Remedial
Actions Program (HAZWRAP) by Thermatrix, Inc., and the Savannah River Technology Center
(SRTC). HAZWRAP was tasked by the DOE Office of Technology Development to perform an
independent cost analysis of the technology being demonstrated.
The FTO provided by Thermatrix, Inc. for the demonstration was a small electrically heated 5 scfm
unit without an integrated caustic scrubber.
The site provided a low flow rate of contaminants during the demonstration, which the FTO handled
with excellent technical performance.
The FTO technology process is scalable, based on the experience of Thermatrix, and provides the
basis for extrapolation of economic performance at higher flow rates.
The conventional technologies of thermal oxidation, catalytic thermal oxidation, and
adsorption/recovery technology were used as the baseline against which FTO was compared for the
treatment of CVOC off-gas from SVE of the vadose zone at the demonstration site. The technologies
were tested at the site with similar contaminant streams using comparable analytical methods. To
compare the three technologies, a number of assumptions were made:
For the purposes of estimating economic performance, calculations were based on a gas
recuperative style remediation grade Thermatrix FTO unit capable of treating 400 scfm of SVE
well head/SVE gaseous effluent.
An SVE concentration of 400 ppmv (equivalent to 3.7 Ib/hr CVOC) was used a basis for
calculating economic performance.
Capital Costs
Capital costs of the baseline and competing technologies of thermal oxidation, catalytic thermal
oxidation, and adsorption/recovery technology are comparable with the FTO technology.
The capital cost of the FTO used in this demonstration was $50,000.
For the purposes of estimating economic performance, the capital cost of a 400-scfm, gas-heated
FTO is $160,000.
Capital equipment costs are amortized over the useful life of the equipment, which is assumed to be
10 years, not over the length of time required to remediate the site.
Operating Costs
The annual operating costs of the baseline, competing, and innovative technologies are comparable.
However, the innovative technology FTO exceeds ORE (>99.99%) of competing technologies.
Thermal catalytic techniques will typically achieve 98% to 99% destruction of PCE.
Adsorption technologies, when operated at reasonable bed loadings, achieve similar removal
efficiencies.
Reliability and durability of the Thermatrix FTO are slightly higher than baseline or competing
technologies.
Thermal catalytic systems need periodic cleaning or replacement of the catalyst, the frequency of
which is highly site dependent (typically, cleaning may be required yearly and replacement required
every 3 years).
The adsorption end of the recovery methods is simple and durable. The regeneration systems involve
mechanical equipment subject to routine breakdown or replacement.
Additional considerations in the evaluation of economic performance of the FTO technology include:
- Total operating costs (including capital recovery, energy, labor, and maintenance) vary from $1 to
$20 per pound of solvent treated for competing and baseline technologies, with the FTO
estimated at $0.72/lb. (Thermal catalytic technologies typically cost $1.65-$2.35/lb CVOC
destroyed.)
10
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U.S. Department of Energy
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- The bulk of the total costs typically originate from capital recovery and labor, with the FTO
technology requiring less maintenance than competing or baseline technologies.
- Energy costs are often viewed as an indicator of a technology's total costs, but typically comprise
only 15-20% of the total operating costs.
• Direct thermal destruction technologies will typically require about twice the energy input of
thermal catalytic techniques.
• Heat recapture systems coupled with thermal technologies decrease system energy
requirements, but the savings due to heat recovery must be balanced against the added
capital and maintenance costs of a heat exchanger and the need for corrosion protection from
HCI generated from destruction of CVOC.
• Solvent recovery methods will generally require 1/4 to 1/3 of the energy used for thermal
techniques.
• Calculations based on the above assumptions put the cost of CVOC destruction at $0.72/lb
($1.58/Kg) CVOC destroyed.
• Common costs not evaluated because of use in all technology systems but that would be required are:
- The destruction technologies demonstrated at SRS did not include acid scrubbers that would be
necessary for full-scale continuous operations. Labor and maintenance costs for the scrubbers
(including handling and disposition of the caustic solutions) would probably exceed that for the
thermal units themselves.
Recovery systems carry an added cost for solvent handling and secondary waste stream
disposition.
However, handling acid scrubber material and waste for thermal units should be on the order of
costs for solvent recovery handling.
Cost Summary
• With this inlet feed concentration, the Thermatrix unit would also require -315,000 Btu/hr
supplemental fuel (natural gas), at a cost of $6,920/yr and minimal electricity at $525/yr.
Technology Cost Comparison
Thermox
Catox
FTO
U.S. Department of Energy
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11
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SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations
The SRS site was previously used for several in situ remediation demonstrations associated with the
VOCs in Non-Arid Soils and Groundwater Integrated Demonstration (VNID) funded by the DOE Office
of Technology Development. Air discharge permits for the demonstration site are in place, and a
letter of intent to the South Carolina Department of Health and Environmental Control served as an
amendment to the existing air permits.
The small scale of the demonstration permitted operation of the FTO without a caustic scrubber to
remove the HCI produced. In large-scale operations, the FTO effluent stream would be coupled with a
caustic scrubber.
The FTO has been permitted for operation in California and in New Jersey, which both have strict
clean air standards and has been permitted in other states, in addition to 14 other states, France, and
the United Kingdom.
Permit requirements for future FTO applications are expected to include:
Air permit for discharge of treated vapor,
CERCLA and RCRA permitting depending on site-specific requirements,
NEPA review for federal projects, and
U.S. DOT certification if propane is transported to the site for operating a large-scale (100 scfm)
FTO unit.
Permit requirements will differ from state to state and for specific applications (e.g., CVOCs vs VOCs).
Safety, Risks, Benefits, and Community Reaction
Worker Safety
• Health and safety issues for the installation and operation of FTO are essentially equivalent to those
for other thermal oxidative or thermal catalytic off-gas treatment technologies.
• FTO treatment of CVOCs produces HCI, which would require neutralization of the acid. Safety issues
similar to those associated with wastes generated from baseline adsorption technologies like
Granulated Activated Carbon would also apply to FTO caustic scrubber waste.
• The FTO contains safety interlocks that prevent potential worker exposure to contaminant vapors in
the event of power or system failure.
• Level D personnel protection was used during the installation and operation of the FTO.
Community Safety
• The FTO does not produce any significant routine release of contaminants. No known hazardous by-
products are produced.
• No unusual or significant safety concerns are associated with the transport of equipment, samples, or
*' other materials associated with the FTO.
• FTO has no open flame, thus eliminating community concerns about incineration.
Environmental Impacts
• The FTO has a low profile and requires little space.
• Visual impacts are minor, and the FTO creates little noise or heat, even in close proximity.
Socioeconomic Impacts and Community Perception
• The FTO has minimal economic or labor force impact.
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U.S. Department of Energy
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• The general public has little familiarity with the FTO; however, the technology has gained public
acceptance.
• FTO is not viewed by the general public as an incineration technology because there are no open
flames, and FTO has found acceptance as a "clean" technology.
U.S. Department of Energy
156
13
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SECTION 7
LESSONS LEARNED
Design Issues
The FTO is designed to utilize heat provided by the thermal oxidative reaction.
The FTO unit would have a lower energy requirement and concurrent lower operational cost when
treating contaminated off-gases with a high heat of combustion (ca. 30 Btu/scf).
CVOCs have a low heat of combustion (<2 Btu/scf at 1000 ppmv each of PCE and TCE) requiring
resistance heating or addition of propane to maintain destruction performance.
The design of the FTO is robust; the FTO required minimal maintenance throughout the
demonstration.
Implementation Considerations
• Treatment of CVOC vapors using the FTO would require incorporating a caustic scrubber into the
treatment system to neutralize HCI generated by the oxidation of CVOCs.
• Applications <100 scfm would require adequate power for resistance heating.
• Applications >100 scfm would require access to propane either by pipeline or by tanker.
Technology Limitations/Needs for Future Development mmmmmmmgm^.-^.. •, ••• <•• •• i
• The FTO is most energy efficient when treating compounds with a high heat of combustion (e.g.,
petroleum hydrocarbons) where heat recapture can boost operational efficiency.
• Moderate to high flow rates (>100 scfm) and contaminated vapor concentrations (>500 ppmv) improve
the overall efficiency of operation and destruction of CVOCs by the FTO.
Technology Selection Considerations
The FTO technology coupled with a baseline or innovative in situ remediation technology would be
most effective during the early stages of remediation when contaminant concentrations tend to be
high.
The FTO has good application to manufacturing, process waste streams, and remediation processes
when the flow rate and contaminant concentrations are moderate to high.
The FTO technology has been demonstrated at SRS and in the private sector to be effective, efficient,
reliable, and cost-effective in the destruction of VOC and CVOC vapors.
The FTO technology is competitive in cost with, and achieves comparable or higher destruction
efficiencies than, commercially available baseline technologies for off-gas treatment, including thermal
oxidative techniques, thermal catalytic techniques, and adsorption/recovery technologies.
14
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U.S. Department of Energy
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APPENDIX A
DEMONSTRATION SITE CHARACTERISTICS
Site History/Background
Site Layout
A-Area \
Roads
M-Aram Procmmm
Sewer/lntagrmted
Demon*tr*Uon
Site
-y—v <> IT^;^
/ ^X: i ffi^i
%Lost Lake
M-Area
— A-O14 Outfall/
Tim's Branch
HWMF/Settllng
Basin
The Savannah River Site's (SRS's) historical
mission has been to support national defense
efforts through the production of nuclear
materials. Production and associated
research activities have resulted in the
generation of hazardous waste by-products
now managed as 266 waste management
units located throughout the 300 mile2 facility.
The A and M Areas at Savannah River have
been the sites of administrative buildings and
manufacturing operations, respectively. The
A/M-Area is approximately 1 mile inward from
the northeast boundary of the 300-mile2
Savannah River Site. Adjacent to the site
boundary are rural and farming communities.
Specific manufacturing operations within the
M-Area included aluminum forming and metal
finishing.
The M-Area operations resulted in the release of process wastewater containing an estimated 3.5
million Ibs of solvents. From 1958 to 1985,2.2 million Ibs were sent to an unlined settling basin, which
Is the main feature of the M-Area Hazardous Waste Management Facility. The remaining 1.3 million
Ibs were discharged from Outfall A-014 to Tim's Branch, a nearby stream, primarily from 1954 to
1982.
Discovery of contamination adjacent to the settling basin in 1981 initiated a site assessment effort
eventually involving approximately 250 monitoring wells over a broad area. A pilot groundwater
remediation system began operation in February 1983. Full-scale groundwater treatment began in
September 1985.
/W
2000ft
Contaminants of Concern
Contaminants of greatest concern are 1,1,2-trichloroethylene (TCE), tetrachloroethylene (PCE), and
11,1,1-trichloroethylene (TCA).
Property at STP*
Empirical Formula
Density
Vapor Pressure
Henry's Law Constant
Water Solubility
Octanol-Water Partition
Coefficient; «„„
Units
-
g/cm3
mmHg
atm*m3/mole
mg/L
-
TCE
CICH=CCI2
1.46
73
9.9E-3
1000-1470
195
PCE
CI2C=CCI2
1.62
19
2.9E-3
150-485
126
TCA
CH3CCI3
1.31
124
1.6E-2
300-1334
148
STP = Standard Temperature and Pressure; 1 atm, 25°C
U.S. Department of Energy
158
15
-------
Nature and Extent of Contamination
• Approximately 71 % of the total mass of VOCs released to both the settling basin and Tim's Branch
was PCE, 28% was TCE, and 1% was TCA.
• The estimated amount of dissolved organic solvents in groundwater in concentrations greater than 10
ppb is between 260,000 and 450,000 Ibs and is estimated to be 75% TCE. This estimate does not
include contaminants sorbed to solids in the saturated zone or in the vadose zone. The area of VOC-
contaminated groundwater has an approximate thickness of 150 ft, covers about 1200 acres, and
contains contaminant concentrations greater than 50,000 pg/L.
• Dense, nonaqueous-phase liquids found in 1991 present challenges for long-term remediation efforts.
• Vadose zone contamination is mainly limited to a linear zone associated with the leaking process
sewer line, solvent storage tank area, settling basin, and the A-014 outfall at Tim's Branch.
Contaminant Locations and Hydrogeologic Profiles
Simplified schematic diagrams show general hydrologic features of the A/M Areas at SRS.
Vadose Zone and Upper Aquifer Characteristics
o1
35'
60-
Ground Surface
Water Tafcte
1601
W//////////////////,
— Legend
• Water Table Q Semiconfined Aquifer
OUnsaturatedZone •ConfinedAquifer
Sediments are composed of sand,
clay, and gravel.
Clay layers are relatively thin and
discontinuous, with the exception of
the clay layers at a 160-ft depth and
a thicker zone of interbedded clay
and sand found at a 90-ft depth.
The water table is approximately
135ft below grade.
A moderate downward gradient
appears to exist beneath the M-
Area. Vertical flow rates have been
estimated to be 2 to 8 ft/year.
Radial flow outward from a
groundwater plateau under most of
the A/M-Area exists. Flow is
approximately 15 to 100 ft/year.
16
159
U.S. Department of Energy
-------
Hvdroaeoloaic Units
Aquttsr
Unto
V«do«*Zon*
DescrioHon
Foorty sorted mix ol und. cobbles, iflt and day
Moderate to wtt-tortad. fin* to medium und
containing tome pebbles; 13% tU and day
Thickness
-STIt -i
0-97 ft L
ModeraMy to wrt-MrtDd medium tand: 18% tin
and day
W«UrT«bt« Unit
Uppw
LattUkaAquilaf
Lower
Crouch Bmnch
Confining Unit
Crouch Branch Aquifer
Moderate to wel-«ortod fine und with tome
cafcanaoua zone*: 2514 silt and day; 14% tilt ind
daybeda
30-55 n
16-34(1
W»J.ioft»d fin* to medium nnd; 16% »Ut ind
day; 7% tit and day btdx.
Dlfa>ntlnuotact*ylnd3 contMMng TOHMtOty
Moderate to wet-rated medum »«nd; 17% iKt 4-44 ft
•nd cky; 7% *» and d»y bed*
Cky, clayey sft,indpooclysort»dfina to cocna, 32-85 R
dtyiy und: 62% silt ind day; contains Z major
cfcylayen the tow of which it 10-56 ft thick and
It the principal confining unit tor lower aquH»r
zone*
Very pooriy to \iwMortid. medh«n to coana
*tnd»: 5% *and and day beds: an Important
production zone lor water tuppty wBte In me M-
Atm
152-180
Metal-degreasing
solvent wastes were
sent to the A-014 outfall
and, via the process
sewer, to the M-Area
settling basin. Data
from hundreds of soil
borings, ground water
monitoring wells, and a
variety of other
investigative techniques
have established a well-
documented VOC
plume in both the
vadose and saturated
zones.
TCE Ground Water Plume (Top View)
Data from 15 feet below water table in
the third quarter of 1990.
2000ft,
O 8.000-16,000 ug/L
0} 16.000-24.000 ug/U
• 24.000- 32.000 ug/L
• 32.000 -40.000 ug/L
• 40.000-48.000 ug/L
• > 48,000 ug/L
U.S. Department of Energy
160
17
-------
TCE Concentrations in Soils (West-East Cross Section)
Concentrations and lithology data were acquired in 1991 along an approximately 200-ft cross section of
the integrated demonstration site. Concentration contours of TCE in sediments are based on analysis of
more than 1000 sediment samples. Highest concentrations of TCE occur in clay zones. These data were
collected before the in situ air stripping demonstration was conducted and do not represent pretest
conditions for the in situ bioremediation demonstration.
Typical
Borehoia
Lithology
o-i
Surface
50-
100-
Sand
i
^NClay
Sand
I
I
1
Sand
day
(figure moor/ted from Raferanca 6)
—- Legend
•oil concentration* OlOOtol.OOOugftg • 5.000 to 10,000 units ug/kg
in ug/Kg pa 11000 to 5.000 ug/kg • >10,000 ug/kg
18
161
U.S. Department of Energy
-------
APPENDIX B
REFERENCES
Allen, M. W., et al., "Flameless Thermal Oxidation for Low Concentration VOC Remediation Waste
Streams: Designs for Planned DOE Demonstrations," presented at the Waste Management '95
Conference, February 26-March 2,1995, Tucson, Arizona.
Jarosch, T. R., R. D. Raymond, and S. A. Burdick, Sampling and Analysis Report: Thermatrix Flameless
Thermal Oxidation Field Demonstration at the Savannah River Site, Westinghouse Savannah River
Company, Savannah River Technology Center, Prepared for Lockheed Martin Energy Systems, Inc.,
Hazardous Waste Remedial Actions Program (HAZWRAP), 1995.
Jarosch, T. R., J. S. Haselow, J. Rossabi, S. A. Burdick, R. D. Raymond, J. E. Young, and K. H. Lombard,
Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of
Chlorinated Volatile Organic Compounds, Westinghouse Savannah River Company, Document Number
WSRC-RP-94-927, September 1994.
Johnson, L. D., "Detecting Waste Combustion Emissions." Environ. Sci. Tech., 20,223,1995
"Demonstration of Eastman Chnstensen Horizontal Drilling System at the Integrated Demonstration Site of
the Savannah River Site," Westinghouse Savannah River Company, Document No. WSRC-TR-92-577,
December 1992.
Martin, R. J., et al., "Selecting the Most Appropriate HAP Emission Control Technology," The Air Pollution
Consultant, Volume 3, Issue 2 (March/April 1993).
Wilboum, R. G., M. W. Allen, and A. G. Baldwin, "Applications of the Thermatrix Flameless Oxidation
Technology in the Treatment of VOCs and Hazardous Wastes," presented at the International Incineration
Conference, May 8-r12,1995, Seattle, Washington.
Wilboum, R. G., et a!., Treatment of Hazardous Waste Using the Thermatrix Treatment System,"
presented at the 1994 Incineration Conference, May 9-13,1994, Houston, Texas.
U.S. Department of Energy
162
19
-------
This report was prepared by:
HAZARDOUS WASTE REMEDIAL ACTIONS PROGRAM
Environmental Management and Enrichment Facilities
Oak Ridge, Tennessee 37831-7606
managed by
LOCKHEED MARTIN ENERGY SYSTEMS, INC.
for the
U.S. DEPARTMENT OF ENERGY
under contract DE-AC05-84OR21400
Contact: Richard Machanoff
(423)435-3173
in conjunction with:
The Colorado Center for Environmental Management
999 18th Street
Suite 2750
Denver, Colorado 80202
Contact: Dawn Kaback
(303) 297-0180 ext. 111
163
-------
-------
Six Phase Soil Heating at the U.S. Department of Energy,
M Area, Savannah River Site, Aiken, South Carolina, and the
300-Area, Hanford Site, Rich land, Washington
16f
-------
Case Study Abstract
Six Phase Soil Heating at the U.S. Department of Energy, M Area,
Savannah River Site, Aiken, South Carolina, and the
300-Area, Hanford Site, Richland, Washington
Site Name:
U.S. Department of Energy (DOE),
Savannah River Site (SRS), M Area
Process Sewer/Integrated
Demonstration Site
(for Hanford Site, see Results)
Location:
Aiken, South Carolina
Contaminants:
Chlorinated Aliphatics
- Trichloroethene (TCE) and
tetrachloroethene (PCE)
- TCE concentrations in the sediments
ranged from 0 to 181 Mg/kg (ppb), and
PCE from 0 to 4,529
Period of Operation:
October 1993 to January 1994
Cleanup Type:
Field demonstration
Technical Information:
Theresa Bergsman, PNL,
(509) 376-3638
Phil Gauglitz, (509) 372-1210
Bill Heath, (509) 376-0554
Harry Burkholder (Licensing),
PNL, (509) 376-1867
SIC Code:
9711 (National Security)
3355 (Aluminum Forming)
3471 (Metal Finishing)
Technology:
Six Phase Soil Heating (SPSH)
- SPSH splits conventional three-phase
electricity into six separate electrical
phases, with each phase delivered to a
single electrode.
- The six electrodes are placed in a
hexagonal pattern, with the vapor extraction
well located in the center of the hexagon.
- At SRS, the diameter of the hexagon was
30 ft, and 1 to 2 gals/hr of water with 500
ppm NaCl was added at each electrode to
maintain moisture. Electrical resistivity
tomography (ERT) was used to monitor
heating progress.
Cleanup Authority:
State: Air discharge and
underground injection control
(UIC) permits for the SRS are
in place with the South
Carolina Department of Health
and Environmental Control
(SCDHEC).
Points of Contact:
Kurt Gerdes, DOE EM-50,
(301) 903-7289
Dave Biancosino, DOE,
(301) 903-7961
Jim Wright, DOE,
(803) 725-5608
Waste Source:
Surface impoundment (unlined
settling basin)
Purpose/Significance of
Application:
SPSH was demonstrated as an
alternative technology for enhancing
removal of contaminants from
clayey soils during an SVE
application
Type/Quantity of Media Treated:
Soil and Sediment
The contaminated target zone was a ten-foot thick clay layer at a depth of
approximately 40 feet, underlain by a thick section of relatively permeable sands
with thin lenses of clayey sediments.
Regulatory Requirements/Cleanup Goals:
- The demonstration was covered by permits issued by the SCDHEC, including an air quality permit and a UIC permit
(because of the addition of NaCl-bearing water to the electrodes).
- No specific regulatory requirements or cleanup goals were identified for the SPSH demonstration.
166
-------
Case Study Abstract
Six Phase Soil Heating at the U.S. Department of Energy, M Area,
Savannah River Site, Aiken, South Carolina, and the
300-Area, Hanford Site, Richland, Washington (Continued)
Results:
- Temperature in the clay zone increased to 100°C within 8 days and held at 100-110° C for 25-day demonstration.
- 19,000 gallons of water were removed from the soil as steam; approximately 5,000 gallons of water were added to
maintain electrode conductivity.
- Median removal of PCE from the soil was 99.7%
- 180 kg of PCE and 23 kg of TCE were removed from the soil within the heated zone.
- SPSH at the Hanford site was conducted in 1993 on an uncontaminated area.
- Results from Hanford were used to improve process understanding, refine system design (e.g., of electrodes), and
address scale-up issues.
Cost Factors:
- No data are provided on the capital or operating costs for the two demonstrations.
- An analysis of the capital and operating costs comparing SPSH and SVE technologies was made based on the
following assumptions: a plume 100 ft in diameter; depth from 20 to 120 ft; energy demand 200 kW-hr per yd3; target
contaminants are VOCs and semi-VOCs.
- SPSH was shown to have a lower cost than SVE ($86/yd3 compared with $576/yd3) and io require less tune for
remediation (5 yrs compared with 50 yrs).
Description:
From 1958 to 1985, Savannah River Area M conducted manufacturing operations including aluminum forming and metal
finishing. Process wastewater from these operations containing solvents (TCE, PCE, and TCA) was discharged to an
unlined settling basin at Savannah River, which lead to contamination of ground water and vadose zone soils.
Treatment of vadose zone soils has been the subject of several demonstrations (e.g., in situ air stripping), including this
investigation of the technical and economic feasibility of six phase soil heating (SPSH) technology.
At SRS, SPSH was used to increase the removal efficiency of SVE for a clayey soil contaminated with TCE and PCE.
At Hanford, SPSH was demonstrated on an uncontaminated site to improve process understanding, refine system design
(e.g., of electrodes), and address scale-up issues. SPSH splits conventional three-phase electricity into six separate
electrical phases, with each phase delivered to a single electrode. The six electrodes are placed in a hexagonal pattern,
with the vapor extraction well located in the center of the hexagon.
Results from the SRS demonstration showed that SPSH increased the temperature in the clay zone to 100°C within 8
days and maintained it at 100-110°C for a 25 day demonstration. In addition, there were 19,000 gallons of water
removed from the soil as steam, and approximately 5,000 gals of water added to maintain electrode conductivity. The
median removal of PCE from the soil was 99.7%, with overall results showing that 180 kg of PCE and 23 kg of TCE
were removed from the soil within the heated zone. Operating difficulties included drying out of the electrodes and
shorting of the thermocouples. The system design was improved to overcome these difficulties.
167
-------
SECTION 1
SUMMARY
Technology Description
Six Phase Soil Heating (SPSH) was developed to remediate soils contaminated with volatile and semi-volatile organic compounds.
SPSH is designed to enhance the removal of contaminants from the subsurface during soil vapor extraction. The innovation com-
bines an emerging technology, that of six-phase electrical heating, with a baseline technology, soil vapor extraction, to produce a
more efficient in situ remediation system for difficult soil and/or contaminant applications.
SPSH is especially suited to sites where contaminants are tightly bound to clays and are thus difficult to remove using soil vapor
extraction alone. Target zones to be treated would most likely be above the water table, but a thicker treatment zone could be
addressed by hydraulically lowering the water table with pumping wells.
Diesel Fuel 480 V Alternate
Truck Power Supply
Voltage Control System
and Transformers
100 ft. dla. Electrode
Circle (185 ft deep)
Rope Safety Barrier
1 Electrical heating increases the temperature of the soil internally by passing standard AC current through the soil moisture.
• Heating is largely dependent on soil moisture; soils of low permeability and high water content are preferentially heated.
• Heating also raises the vapor pressure of volatile and semi-volatile contaminants, increasing their volatilization and concomi-
tant removal from the soil via vapor extraction.
* Heating dries the soil and creates steam which 1) increases the permeability of the formation (this may be quite beneficial in
tow permeability materials), and 2) strips contaminants that may not be removed via simple soil vapor extraction.
1 SPSH splits conventional three-phase electricity into six separate electrical phases, producing an improved subsurface heat dis-
tribution. Each phase is delivered to a single electrode, each of which is placed in a hexagonal pattern. The vapor extraction
well, which removes the contaminants, air, and steam from the subsurface, is located in the center of the hexagon.
Alternative extraction (venting) configurations may be applied.
1 SPSH delivers significantly more power to the bulk soil and less at the electrodes than other resistive heating techniques.
1 SPSH uses conventional utility power transformers at a relatively low capital cost as compared to other electrical heating tech-
niques.
1 SPSH does not require permeable soils as does soil vapor extraction and as do most other heating methods.
• SPSH can accelerate remediation by
• better removing contaminants from low permeability and heterogeneous soils,
• enhancing removal of less volatile contaminants.
Page 1
U.S. Department of Energy
168
-------
SUMMARY
continued
Technology Status
Field demonstrations were conducted as part of two Department of Energy (DOE) Integrated Demonstration Programs: VOCs in
Soils and Ground Water at Nonarid Sites (Savannah River) and VOCs in Soils and Ground Water at Arid Sites (Hanford):
U.S. Department of Energy
Savannah River Site
M Area Process Sewer/Integrated Demonstration Site
Aiken, South Carolina
October 1993 to January 1994
U.S. Department of Energy
Hanford Site
300 Area
Richland, Washington
1993
The demonstration site at the Savannah River Site was located at one of the source areas within the one-square mile VOC ground
water plume. The contaminated target zone was a ten-foot thick clay layer at a depth of approximately 40 feet. Prior to application
of SPSH, trichloroethylene (TCE) and tetrachloroethylene (PCE) concentrations in sediments ranged from 0 to 181 ug/kg and 0 to
4529 ug/kg. The site is underlain by a thick section of relatively permeable sands with thin lenses of clayey sediments. Appendix A
describes the site in detail.
The demonstration site at Hanford was located in the 300 Area at an uncontaminated, undisturbed site. The objective of the demon-
stration was to improve the understanding of the six-phase heating process, refine design of electrodes and other system compo-
nents, and address scale-up issues in the field.
Key Results of the SRS Demonstration
• 99.7% of contaminants were removed from within the electrode array. Outside the array, 93% of contaminants were removed at a
distance of 8 feet from the array. This difference indicates that heating accelerates the removal of contaminants.
• Temperatures within the array were elevated to 100 degrees C after 8 days of heating and were maintained for 17 days. Eight
feet outside the array, temperatures were elevated to 50 degrees C.
• Clays were heated more rapidly than the adjacent sands.
• The efficiency of contaminant removal increased with increased soil drying due to heating.
• 19,000 gallons of condensed steam were removed from the extraction well, indicating substantial drying of the soil.
• Offgas concentrations showed little change during heating, most likely because the soil vapor extraction system affected an area
of influence greater than the area of heating.
• Completion of a cost-benefit analysis by Los Alamos National Laboratory (LANL) showing that SPSH could be performed for a
cost of $88/cubic yd. assuming that a contaminated site of 100 feet in diameter and 20 to 120 feet deep could be remediated in
five years.
• SPSH is estimated to reduce the time required to remediate such a site from 50 years for the baseline technology of SVE to five
years.
SPSH is patented by Battelle Pacific Northwest Laboratory. Battelle is working closely with commercial vendors via nondisclosure
agreements with the goal of licensing the technology. SPSH has been selected as the remediation technology of choice at a conta-
minated site at the DOE Rocky Flats Environmental Technology Site where remediation will be initiated in the spring of 1996.
Licenses are available through Battelle Pacific Northwest Laboratory.
Contacts ^.r^^,,.^^ '- §^^rr-7T^r^_ ._.—^
Technical
Theresa Bergsman, Principal Investigator, Battelie Pacific Northwest Laboratory (PNL), (509) 376-3638. Other technical contacts:
Phil Gauglitz and Bill Heath, (509) 372-1210 /(509) 376-0554.
Management
KurtGerdes, DOE EM-50, DOE Integrated Demonstration Program Manager, (301) 903-7289.
Dave Biancosino, DOE EM-50, DOE Integrated Demonstration Program Manager, (301) 903-7961.
Jim Wright, DOE Plumes Focus Area Implementation Team Manager, (803)725-5608.
Licensing Information
Harry Burkholder, PNL, (509) 376-1867
Page 2
169
U.S. Department of Energy
-------
SECTION 2
TECHNOLOGY DESCRIPTION
Overall Process Schematic
Voltage Control System
and Transformers
• Six electrodes, through which electrical power is applied to the subsurface, are placed in the ground in a hexagonal pattern. At
SRS, the diameter of the hexagon was 30 feet. The extraction well is placed in the center of the hexagon.
1 To maintain soil conduction at the electrodes, they are backfilled with graphite and small amounts of water containing an elec-
trityte are added to maintain moisture. At SRS 1 to 2 gallons/hour of water with 500 ppm NaCI was added at each electrode.
The actual rate of water addition depends upon soil type.
• An offgas treatment system treats the contaminated vapors removed from the subsurface. At SRS, electrical catalytic oxidation
was used for the demonstration, but other technologies are available.
1 Bectrical resistivity tomography (ERT) was used to monitor the progess of the heating of the subsurface.
Page3
U.S. Department of Energy
170
-------
TECHNOLOGY DESCRIPTION
continued
Above Ground System
Condensed Water
Storage Tank Condenser
(one of six) injection Water
Catox
Off-Gas
Treatment
System
MHV-31
\
Electrode
Six-Phase
Power Supply.
MHV-39«
Power Plant
(750kVA)
S9409009.18
sftl
•
Location of Monitoring Wells, Electrodes, and Surface Equipment (well
locations are drawn to scale; surface equipment is not)
• The 750KVA trailer-mounted power plant supplied 480 V of three-phase power to a six-phase power transformer. The six-phase
transformer was rated at 950kVA. Total power applied averaged 200RW. A remote computer controlled output voltages for each
electrode.
• The electrodes were connected to the transformer via insulated power cables lying on the surface.
• The soil surrounding each electrode was supplied with water through a drip system.
• The vacuum system removed contaminant vapors and air from the subsurface; the vapors were passed through a condenser to
remove the steam generated by the heating.
• The water that collected in the central extraction well was removed with an air-actuated piston pump with remote speed control.
• The generated VOCs were treated by electrically heated catalytic oxidation.
Page 4
171
U.S. Department of Energy
-------
TECHNOLOGY DESCRIPTION
continued
Below Ground System C
/ UHV31 UHV34 UHV30 UHV37 UHV3* UHV38 MHV40 UHV41
V«nt OW1 OWZ OW3 PT1 PT3
XX
• 34 n
) 30ft
FlterPKfcSanti
Subsurface Depth for Two Typical Electrodes, Central Vent, and Monitoring Wells
The clay zone is indicated by the shaded region for the wells that were cored
and logged; the clay zone was continuous through the test area. The symbols
show the depth of temperature and pressure measurements.
' Vertical placement of the electrodes, the central extraction well, and monitoring wells is depicted above. The target clay zone,
approximately 30 to 40 feet in depth, is indicated by the shaded region for the cored wells. The electrodes were placed between
23 and 44 feet below ground surface. The other symbols indicate the location of the temperature and pressure measurement
devices (thermocouples and pressure transducers).
1 ERT utilized 4 boreholes in which resistivity electrodes were installed. Data were collected so that images could be obtained from
5 vertical planes, three of which intersected the heating array, i.e the hexagon.
1 Automation and computer control of the SPSH system allowed unattended operation after an initial start-up period.
boreholes with
ERT electrodes
I... .\.../.
I •/ • '
, . ..j^r. .r —. -*--^- • • »;'• • • • y ">^
*f*\\ '.'.'.'.'.'.'.'.'. ."7 ^^^: : : '.. heating electrodes located
N MI' ' ' ' ' :/ between depths of 23 and
.5 . ' 43 ft ^
approximate.,
region of ^
maximum
heating
Figure 1. Plan view of the experimental site showing the location of the boreholes used for
ERT (e1, e2, e3, e4), extraction well and the ohmic heating electrodes. The clay layer targeted
for this demonstration is located between 9.14 to 12.5 m (30 and 41 ft) of depth
PageS
U.S. Department of Energy
172
-------
SECTION 3
PERFORMANCE
Demonstration Plan
• Performance of the technology has been assessed using information from the initial clean-site field demonstration at Hanford and
the demonstration at a contaminated site at SRS.
« Major objectives of the SRS demonstration included:
• accelerated removal of TCE and PCE from clay soils at a depth of 30 to 40 feet
• quantification of the areal and vertical distribution of heating (30-foot diameter circular array)
• demonstration of functional electrode and extraction well designs
• demonstration of economic feasibility of commercial application of the technology
• Major elements of the SRS demonstration included:
• pre-test drilling and soil sampling
• baseline SVE test without heating (12 days)
• SPSH with venting (25 days)
• venting after heating
• post-test soil sampling
Treatment Performance i.^^,^^^^^,^^^^^^,^^^^^^.- ,„,. , u • , =
Key System Parameters
• Vacuum Applied
• Air was extracted continuously during the demonstration.
• Power Applied
• An average power of 200kW was applied to the electrode array. A total of 1OO.OOOkWh of energy was applied.
• Mean voltage was 1000V. At the end of the heating period, voltage was increased to 2400V to maintain power input lev-
els.
350
300
250
3 200
<£ 150
100
50
L-l^*f
11/2/93 11/7/93 11/12/93 11/17/93 11/22/93 11/27/93 12/2/93 12/7/93
Power Applied to SPSH Array
*Periods when power is zero, indicate times when the system was shutdown for maintenance or data gathering
Page 6
173
U.S. Department of Energy
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PERFORMANCE
continued
Cumulative Energy Applied to the Soil
100,000 -
80,000 -
i 60,000
CD
I
40,000 -
20,000 -
11/2/93 11/7/93 11/12/93 11/17/93 11/22/93 11/27/93 12/2/93 12/7/93
Time
Zones of Influence
• Electrical resistance tomography (ERT) was used to map the zone of influence and effects of heating and drying on the soil.
• A difference image representing the changes in electrical conductivity observed after two weeks of heating is shown below.
The difference tomograph shows the combined effects of moisture redistribution and heating caused by six-phase heating
and vapor extraction.
• The tomograph shows that most of the clay layer increased in electrical conductivity (up to twice initial values) during the first
three weeks.
• After that time, conductivity decreased to as low as 40% of the pre-test value, as a result of the drying of the soil. At that
time, clay saturation was estimated to be as low as 10%.
Depth, ft.
10 t-
range of depths for
the clay layer based
on core samples
(from Gauglitz et al,
1994b)
temperatures
measured (C)
e2
-0.005
0.005
Page?
U.S. Department of Energy
174
-------
PERFORMANCE
continued
Thermal Performance
• Temperature in the clay zone was increased to 100 degrees C within eight days and was maintained at 100 to 110 degrees C for
the 25-day heating campaign. Within the adjacent sands, temperatures increased to 100 degrees C within 10 to 15 days.
Well
MHV-38 100
O
80
60
CD
Q.
.03 40
20
27'
34'
36'
39'
10/18/93
10/28/93
_L
- Heating •
J
_L
11/7/93
11/17/93
11/27/93
12/7/93
Well
MHV-40
o
of
100
80
,0) 40
20
27'
34'
36'
39'
10/18/93
10/28/93
JL
- Heating •
J
11/7/93
11/17/93
11/27/93
12/7/93
Note: MHV-38 was located midway between two electrodes.
Thermocouples at 27 and 43 feet represent sands above and below the target clay
Thermocouples at 34 and 36 feet are within the target clay, at 39 feet in the sand immediately adjacent to the clay.
Ouside the electrode array, 23 feet from the central extraction well, temperatures were increased to 50 degrees C.
PageB
175
U.S. Department of Energy
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PERFORMANCE
Well
MHV-39
(outside
the array)
o
100
80
i 60
40
20
continued
27'
34'
36'
39'
I
10/18/93
10/28/93
I
• Heating •
11/7/93
11/17/93
11/27/93
12/7/93
1 Temperatures in the clay zone were quite uniform from the central extraction well to the electrodes and beyond (see below). Of
course, temperatures outside the array are lower (see above).
100 -
20
10
Radial Position, ft
20
• Heating of the clays dried the soil and increased air permeability. However, core samples showed no evidence of fracturing.
Permeabilities of the clays were still much less than the adjacent sands.
* As heating was initiated, the electrical resistance of the soil decreased as expected. However, as the soil actually dried out,
the electrical resistance increased.
• 19,000 gallons of water were removed from the soil as steam. Approximately 5,000 gallons of water were added to maintain
conductivity of the soil at the electrodes.
Page 9
U.S. Department of Energy
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-------
PERFORMANCE
continued
Treatment Performance
o
D -D Pre-Test (MHV-38)
Post-Test (MHB-38)
I
100 200
PCE Concentration, ppm
300
400
1 Pre- and post-test soil samples show a tremendous difference in concentrations of PCE. Samples were collected from the same
depth in adjacent boreholes. Samples collected from the borehole for monitoring well MHV-38 are shown above.
20
_
o.
CO
CO
&
10
Clay Zone
30 to 40 ft Depth
Median Removal
99.7%
Below
90%
90% to
99%
99% to
99.9%
99.9% to
99.99%
Percent PCE Removed
Above
99.99%
• Median removal of PCE from samples in the clay zone was 99.7%. The figure above shows the percentage of PCE removed in
all samples in the clay zone within the electrode array. The wide variation is due to the heterogeneity in soil type.
Page 10
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PERFORMANCE
continued
The figures below show a three-dimensional image of the distribution of TCE before and after the heating demonstration.
Post-test models show almost complete removal of VOCs from the heated zone.
• Median removal of PCE from the clay eight feet outside the electrode array was 93%.
• Results for TCE removal both inside and outside the electrode array were equivalent.
* Removal of volatile contaminants from low-permeability soil is accelerated by steam creation within the soil. The effect of mois-
ture removal from the soil, i.e drying of the soil, on the percentage of PCE remaining is shown below.
1000
100
g 10
'g
'(0
-------
PERFORMANCE
continued
• Mass removal rates increased as the soil dried out and thus increased permeability within the clay zone. This is a better measure
of the acceleration of the remediation than simple measurement of the offgas concentrations.
• Offgas concentrations were not affected by the heating. One reason for this may be that the actual area of influence affected by
the soil vapor extraction system was greater than the zone of heating. Mass removal from the extraction well is shown below.
0)
"3
2
CD
10/22/93
11/2/93
11/13/93
11/24/93
12/5/93
S9409009.16
• Pre- and post-test soil samples indicate that 180 kg of PCE and 23 kg of TCE were removed from the soil. These amounts are
less than that extracted from the central extraction well (475 kg PCE and 107 kg TCE). This also supports the view that the soil
vapor extraction system was effective beyond the 15 foot radius of the heated zone.
Related Testing and Demonstration
• A field demonstration was conducted at a clean site in the 300 Area at Hanford to verify the predictions for heating the soil and to
refine the engineering design of the system. A single 20-ft. diameter hexagonal array was installed for the demonstration. Six
electrodes, six-inches in diameter, were installed to a depth of 10 feet. Data collected during the demonstration included in situ
soil temperatures, voltage profiles, and moisture profiles (using a neutron-probe technique).
• A bench-scale test combining SPSH and In Situ Corona removed greater than 99.999% benzene and greater than 99.994% naph-
thalene fom a tight Hanford silt.
• A bench-scale test combining SPSH and the High Energy Corona offgas system demonstrated TCE removal from soil.
• A bench-scale test to accelerate biodegradation rates in soils was conducted by heating the soil to 30 to 35 degrees C.
Page 12
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SECTION 4
TECHNOLOGY APPLICABILITY AND ALTERNATIVE TECHNOLOGIES
Technology Applicability
• SPSH has been demonstrated to enhance remediation of clay-rich soils contaminated with VOCs in the unsaturated zone.
Bench-scale tests demonstrated that SPSH is effective on lower volatility compounds and can be used to accelerate biodegrada-
tion rates in soils.
• SPSH Is well suited for sites with highly stratified soils containing low permeability layers.
• SPSH has demonstrated that it can remove 99.7% of the volatile contaminants in clay-rich soils within a very short time period
(less than one month), thus accelerating the remediation process over the accepted baseline technology.
Competing Technologies
• SPSH competes with a) the baseline technologies of 1) soil vapor extraction and 2) removal and treatment or disposal, b) other
innovative thermal enhanced vapor extraction technologies and c) other innovative technologies such as bioventing and deep soil
mixing.
1 The effectiveness of SPSH was compared with performance data from soil vapor extraction alone, both before and after heating
occurred. A cost analysis performed by Los Alamos National Laboratory (LANL), desribed in section 5, compares SPSH to the
baseline soil vapor extraction, to the baseline of excavation and removal, to three-phase electrical heating, and to dynamic under-
ground stripping.
1A variety of in situ thermal treatment technologies have been either demonstrated or developed through DOE, DOD, and EPA pro-
grams. The aggregate experience with these programs enhances confidence in the fundamentals of thermal enhancement tech-
nologies. Full-scale demonstrations of in situ thermal technologies included those shown in the table on p. 15.
Page 13
U.S. Department of Energy
18Q
-------
TECHNOLOGY APPLICABILITY & ALTERNATIVES
continued
Competing Technologies (continued)
,\"Jechnotogy ^
v- •?
<. Developer %
',» Basic Principle*
Status/Comments ',
DOE
1
Dynamic
Underground
Stripping
2
Thermal Enhanced
Vapor Extraction
(TEVES)
3
Radio Frequency
Heating
Lawrence Livermore
National Laboratory
(LLNL)
Sandia National
Laboratories (SNL)
KAI Technologies,
Inc.
Combines electrical heating ,
steam injection, and soil vapor
extraction; uses electrical
resistance tomography to
monitor process
Combines soil vapor
extraction with poweriine
frequency (ohmic/electrical)
and radio-frequency soil
heating
Radio frequency heating of
soils combined with soil
vapor extraction
Full-scale demonstration at DOE Lawrence
Livermore National Laboratory at gasoline
spill site in 1993; /licensing discussions
ongoing
Full-scale demonstration initated in 1995
at SNL chemical waste landfill in part of
the Mixed Waste Landfill Integrated
Demonstration; builds upon previous
demonstrations at Volk Field, Wl, Rocky
Mountain Arsenal, CO, and Kelly AFB, TX
(see EPA projects)
Field demonstrated on VOC
contaminated soils using a horizontal well
at the DOE Savannah River Site as part
of the VOC in Non-Arid Soils and Ground
Water Integrated Demonstrationin 1 993
EPA/DOD
1
Contained Recovery
of Oily Wastes
(CROW™)
2 HRUBOUTR
Process
3
In Situ Steam and
Air Stripping
4 In Situ Steam
Enhanced
Extraction Process
5 In Situ Steam
Enhanced
Extraction Process
6
Radio Frequency
Heating
7
Steam Enhanced
Recovery System
Western Research
Institute
Hrubetz
Environmental
Services, Inc.
Novaterra, Inc.
(formerly Toxic
Treatments USA, Inc.)
Praxis Environmental
Technologies, Inc.
Udell Technologies,
Inc.
Illinois Institute of
Technology Research
Institute/Halliburton
NUS
Hughes Environmental
Systems, Inc.
Steam or hot water
displacement guides
contamination to extraction
wells
Hot air injection combined
with a surface exhaust
collection system
Portable steam and air
injection device (Detoxifier™)
used in soils
Steam injection/vacuum
extraction (same as 5 and 7)
Steam injection/vacuum
extraction (same as 4 and 7)
Radio frequency heating of
soils combined with soil
vapor extraction
Steam injection/vacuum
extraction (same as 4 and 5)
EPA SITE field demonstration underway
at the Pennsylvania Power & Light
Brodhead Creek Superfund site, PA;
pilot-scale demonstrations completed at
a wood treatment site in Minnesota
EPA SITE field demonstration on JP-4
contaminated soils completed at Kelly
AFB, TX, in 1993
EPA SITE field demonstration conducted
on VOC and SVOC contaminated soils at
the Annex Terminal, San Pedro, CA, in
1989
Field demonstrations underway at Hill
AFB, UT, and McClellan AFB, CA
Field demonstrations underway at Naval
Air Stations Lemoore and Alameda in
California; Udell technologies no longer
in existence
EPA SITE field demonstration completed
at Kelly AFB, TX, in 1993; earlier
demonstrations occurred at Rocky
Mountain Arsenal, CO, and Volk Reid,
Wl; demonstration cofunded by DOE
EPA SITE field demonstration completed at
the Rainbow Disposal Site in Huntington
Beach, CA, from 1991 to 1993; Hughes no
longer offering technology
•Page 14
Further information on these full-scale applications is available in references 16 (DOE programs) and 5 (DOD/EPA
programs). In addition EPA's Vendor Information System for Innovative Treatment Technologies (VISITT) electronic
database lists additional suppliers of equipment and services related to in situ thermally enhanced recovery of
contaminants. These include:
• Bio-Electrics, Inc., Kansas City, MO
• EM&C Engineering Associates, Costa Mesa, CA
• SIVE Services, Dixon, CA
• Thermatrix, Inc., San Jose, CA
181
U.S. Department of Energy
-------
TECHNOLOGY APPLICABILITY AND ALTERNATIVES
continued
Patents/Commercialization/Sponsor
> The primary sponsor is the U.S. Department of Energy, Office of Environmental Management, Office of Technology Development.
»The technology is currently available for licensing. A commercialization plan has been written. Battelle is currently working with
commercial partners to deploy the technology.
• Three patents have been granted and one patent has been applied for:
•Patent 5,330,291 "Heating of Solid Earthen Material, Measuring Moisture and Resistivity," W.O. Heath, R.L Richardson, and
S.C. Goheen assignors to Battelle Memorial Institute.
•Patent 5,347,070 Treating of Solid Earthen Material and A Method for Measuring Moisture Content and Resistivity of Solid
Earthen Material," W.O. Heath, R.L. Richardson, and S.C. Goheen assignors to Battelle Memorial Institute.
•Patent 4,957,393 "In Situ Heating to Detoxify Organic-Contaminated Soils," J. L. Buelt and K. H. Oma, assignors to Battelle
Memorial Institute.
Page 15
U.S. Department of Energy
182
-------
SECTION 5
COST
Introduction
• Information in this section was prepared from data provided by Battelle Pacific Northwest Laboratory to the Los Alamos National
Laboratory, tasked by the DOE Office of Technology Development to perform an independent cost analysis of the technology
under demonstration.
• The conventional technology of soil vapor extraction (SVE) was used as the baseline technology, against which SPSH was com-
pared.
• The LANL cost comparison for the thermally enhanced VOCs extraction technology was not meant to involve comprehensive cost
estimation of these thermal systems. Thus, the final cost per cubic foot may not match actual remediation numbers exactly.1
• In order to compare the innovative and the baseline technology, a number of assumptions were made:
• The preliminary cost information is based on clean up of a plume described as:
• 100 ft diameter
• Begins at a depth of 20 ft and ends at 120 ft
• Typical energy demand is between 200 kW-hr ($5 to $15) per cubic yards (or 1.05 and 7.407 kW-hr per cubic feet) or
450 kW per array from line power.
• Target contaminants - VOCs and semi-VOCs
• Volatilized contaminants are sent to a catalytic oxidation system for destruction.
• Capital equipment costs are amortized over the useful life of the equipment, which is assumed to be 10 years, not over
the length of time required to remediate a site.
• Energy consumption is an important factor in considering the economic feasibility of SPSH technology. During the SRS demon-
stration:
• 100,000 kWh of energy was applied to an estimated 1100 cubic meters of soil (heated to above 70 degrees C). The calculat-
ed energy consumption is $7/cubic meter at $0.07/kWh.
• The energy cost to heat the soil is small when compared to capital equipment costs and operator time.
Capital Costs ^sa
Cost Category
Cost Description
Total ($)
Direct Cost
Construction Management
Engineering, Design, and
Inspection
Project Management
Contingency
Project Total
Mobilization
Power Source
Water Source
AC Applications Well
Site Characterization/Well Installation
SVE Pilot Testing
Permitting
Vacuum System
Treatment System
Dismantlement/De-Mobilization
Start up and First Month of Operation
9,000
286,000
24,400
53,700
53,100
13,000
16,300
174,500
50,800
22,500
21,400
72,500
181,200
43,500
255.400
1,277,300
Page 16
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U.S. Department of Energy
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COST
continued
Operating Costs i
Cost Category
Direct Cost
Description
Field Monitoring
Monitoring and Reporting
System Operation and Maintenance
Total O & M Costs
Total
($/month)
6,300
4,800
5.800
16,900
Cost Comparison for Thermally Enhanced VOC Extraction Technologies2
The costs to clean up a cubic yard of soil for the duration of remediation activities using SPSH and SVE are presented in the follow-
ing table.
1 Technology
SPSH
SVE
! Cleanup
Duration
(year)
5
50
Amortized
Total Cost
($M)3
2.724
33.358
Total Volume
Remediated
(cubic yards)
785,000
785,000
Total Cost ($)/
Cubic Yards
86
576
12
ca
60
50
40
30
20
10
/
Jt
h
/
SPSH
600
1 500
J3 400
X 300
^ 200
§ 10°
"^
/
j-
/
SVE
SPSH
SVE
1 Memo from S. Booth to D. Kaback dated March 22,1995 (Re: Thermally Enhanced VOC Extraction Cost Data)
2 Letter from P.A. Gauglitz, Battelle PNL to J. Bremser, LANL, dated 1 /25/95
3 Total cost (capital and O&M) is amortized with a discount rate of 2.5%.
Page 17
U.S. Department of Energy
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-------
SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations i •Mui^j^ , ^ ;—^
• Permit requirements for the demonstration were controlled by the South Carolina Department of Health and Environmental
Control (SCDHEC) and included 1) an Air Quality Permit and 2) an Underground Injection Permit (because of the addition of
NaCI-bearing water to retain moisture at the electrodes). A NEPA checklist was also prepared; a categorical exclusion was
granted.
• Permit requirements for future applications of SPSH are expected to include:
• On-site air quality monitoring and air permit for ground-extracted and discharged vapor streams would be required. Permits
would require compliance with the Clean Air Act.
• A special permit may be required to treat, contain, and dispose of the secondary waste stream, which contains liquid conta-
minants condensed from soil off-gas.
• Depending on whether the site is being cleaned up under CERCLA or RCRA or both, other requirements may apply.
• For example at SRS, the M-Area HWMF RCRA Part B Permit must be reviewed to determine if a permit modification
is necessary.
• Groundwater Protection Standards (GWPS) have been established as a part of a RCRA permit. The GWPs are based on
EPA Maximum Contaminant Levels (MCLs). Specific goals for contaminants of greater concern for the M-Area at SRS are:
compound
concentration fppb]
TCE
PCE
TCA
5
5
200
A special safety permit may be required for handling high voltage power suppliers-
Federal sites would require NEPA review.
Safety, Risks, Benefits, and Community Reaction b
Worker Safety
• This technology will be set up with engineered barriers to prevent worker exposure to high voltages.
• The presence of buried metal objects presents a safety hazard. Technologies such as ground penetrating radar must be utilized
to map the subsurface before the heating system is installed.
• A potential explosion hazard exists. If concentrated fumes are released from the vacuum unit, the conditions may create a poten-
tial explosion.
• Other health and safety issues for the installation and operation of SPSH are essentially equivalent to those for conventional
technologies of pump-and-treat or soil vapor extraction.
• Level D personnel protection was used during installation and operation of the system.
Community Safety
• SPSH with offgas treatment should not produce any routine release of contaminants at a significant level to affect the public.
• No unusual or significant safety concerns are associated with the transport of equipment, samples, waste, or other materials
associated with SPSH.
• The transportation and packing of the equipment should meet DOT requirements (on trailers no larger than 8 ft wide by 10 ft by
40 ft long).
• Barriers enclose the treated area to prevent direct access to the site.
Page 18
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U.S. Department of Energy
-------
REGULATORY/POLICY ISSUES
continued
Environmental Impacts
• Treated soil, left in place, will be dry. Soil moisture can be restored with further or no follow-up treatment.
* The treated area will need to be defoliated and evened with a bulldozer.
Socioeconomic Impacts and Community Perception
• SPSH has a minimal economic or labor force impact.
• The general public has limited familiarity with SPSH; however, the technology received positive support on public visitation days
at Savannah River. It has also been explained to the public at Hanford and received positive input.
Page 19
U.S. Department of Energy
186
-------
SECTION 7
LESSONS LEARNED
Design Issues i«*««««""""«»«*"««^^
• The success of the SPSH process is dependent upon boiling the subsurface environment, drying the soil and thus increasing per-
meability of tight formations.
• The extraction well should be screened both above and below the clay target zone to ensure sufficient vacuum pressure to allow
for removal of steam generated in the subsurface. This extraction well design also ensures total capture of contaminants released
as a result of the heating.
• The offgas treatment system must be sized to handle anticipated peak extraction rates and the expected distribution of VOCs in
extracted vapor and liquid streams.
• The vacuum pump must be sized to accomodate removal of the subsurface steam that is generated.
• Concern about buried metal objects and the issue of worker saftey must be addressed and considered when designing a field
application.
Implementation Considerations [••••••••^^ i - •'• • • • • "•' •' '^
• Operational difficulties encountered included drying out of the electrodes and shorting of the thermocouples. The field experience
allowed for improving the design of the system to overcome these difficulties.
Technology Limitations/Needs for Future Development '•••••«™ , i.... - > . •=-*
• Longer-term performance data are required to assess the need for design improvements and system optimization. This informa-
tion can then be used to better quantify life-cycle costs.
• Optimization of electrode design and design of the water injection system should be addressed in future applications.
• Questions still remain as to how power should be applied to the subsurface with an emphasis on how quickly the soil should be
heated. A better understanding of the affects of site specific conditions will also be gained after additional applications/demonstra-
tions are completed.
Page 20
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U.S. Department of Energy
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APPENDIX A
DEMONSTRATION SITE CHARACTERISTICS
(Site History/Background i
• The Savannah River Site's historical mission has been to
support national defense efforts through the production of nuclear
materials. Production and associated research activities have
resulted in the generation of hazardous waste by-products now
managed as 266 waste management units located throughout the
300 mile2 facility.
• The A and M Areas at Savannah River have been the site of
administrative buildings and manufacturing operations,
respectively. The A/M-Area is approximately one mile inward
from the northeast boundary of the 300 mile2 Savannah River
Site, Adjacent to the site boundary are rural and farming
communities. Specific manufacturing operations within the M-
Area included aluminum forming and metal finishing.
Site La
lyout
M-Area Process
Sewer/Integrated
Demonstration
Site
M-Area
A-014 Outfall/
Tim's Branch
HWMF/Settling
Basin
• The M-Area operations resulted In the release of process
wastewater containing an estimated 3.5 million Ibs. of solvents.
From 1958 to 1985,2.2 million Ibs. were sent to an unlined settling
basin, which Is the main feature of the M-Area Hazardous Waste
Management Facility (HWMF). The remaining 1.3 million Ibs. were
discharged from Outfall A-014 to Tim's Branch, a nearby stream,
primarily during the years 1954 to 1982.
• Discovery of contamination adjacent to the settling basin in 1981 initiated a site assessment effort eventually involving
approximately 250 monitoring wells over a broad area. A pilot ground water remediation system began operation in
February 1983. Full-scale ground water treatment began in September 1985.
* High levels of residual solvent are found in the soil and ground water near the original discharge locations.
Technologies to augment the pump-and-treat efforts, for example soil vapor extraction, ISAS, and bioremediation, have
been tested and are being added to the permitted corrective action.
I Contaminants of Concern (
Contaminants of greatest concern are:
1,1,2-trichIoroethylene (TCE)
tetrachloroethylene (PCE)
1,1,1-trichloroethane (TCA)
Property at STP*
Empirical Formula
Density
Vapor Pressure
Henry's Law
Constant
Water Solubility
Qctarjol-Water
Coefficient; Kow
Units
g/cm^
mmHg
TCE
ocH=cct
1.46
73
atm*m3/mole9.9E-3
mg/L
1000-1470
195
"STP = Standard Temperature and Pressure;
PCE
> q;>C=CCfe
1.62
19
2.9E-3
150-485
126
1atm,25°C
TCA
CHgCCfc
1.31
124
1.6E-2
300-1334
148
• Approximately 71% of the total mass of VOCs released to both the settling basin and Tim's Branch was PCE, 28%
was TCE, and 1% was TCA.
• The estimated amount of dissolved organic solvents in ground water in concentrations greater than 10 ppb is between
260,000 and 450,000 Ibs and is estimated to be 75% TCE. This estimate does not include contaminants sorbed to
solids in the saturated zone or in the vadose zone. The area of VOC-contaminated ground water has an approximate
thickness of 150 feet, covers about 1200 acres, and contains contaminant concentrations greater than 50,000 ug/L.
• DNAPLs found in 1991 present challenges for long-term remediation efforts.
• Vadose zone contamination is mainly limited to a linear zone associated with the leaking process sewer line, solvent
storage tank area, settling basin, and the A-014 outfall at Tim's Branch.
. PageAl _
U.S. Department of Energy
188
-------
DEMONSTRATION SITE CHARACTERISTICS
continued
Contaminant Locations and Hydrogeologic Profiles
Simplified schematic diagrams show general hydrologic features of the A/M Area at SRS.
Vadose Zone and Upper Aquifer Characteristics
Ground Surface
351
60'
130'
160'
Water Table
////////////////////A
(figure modified from Reference 12)
~Legend :
• Water Table Q Semiconfined Aquifer
I I Unsaturated Zone Si Confined Aquifer
• Sediments are composed of sand, clay and gravel.
• Clay layers are relatively thin and discontinuous, with the
exception of the clay layers at 160-foot depth and a thicker
zone of interbedded clay and sand found at 90-foot depth. A
clay layer at 30 to 40 feet in depth is the target for this
demonstration. This clay is discontinuous on the scale of the
entire A/M Area, but not across the site of this demonstration.
• The water table is approximately 135 feet below grade.
• A moderate downward gradient appears to exist beneath
the M-Area. Vertical flow rates have been estimated to be
2 to 8 ft/year.
• Radial flow outward from a ground water plateau under most
of the A/M-Area exists. Flow is approximately 15 to 100
ft/year.
Hvdroaeologic Units
Aquifer
Unit
Vadose Zone
Description Thickness
Poorly sorted mix of sand, cobbles, silt and clay -57 ft -
Moderate to well-sorted, fine to medium sand 0-97 ft
containing some pebbles; 1 3% silt and clay
MnrieratAlu In wpll-snrtpri mprihtm «anri- 1 R0/, cilt 3n.RR ft —
\
Water Table Unit
Upper
Lost Lake Aquifer
Lower
Crouch Branch
Confining Unit
Crouch Branch Aquifer
and clay
Moderate to well-sorted fine sand with some
calcaneous zones; 25% silt and clay; 14% silt and
clay beds
Well-sorted fine to medium sand; 16% silt and
clay; 7% silt and clay beds.
Discontinuous clay beds containing 70% silts clay
Moderate to well-sorted medium sand; 17% silt
and clay; 7% silt and clay beds
Clay, clayey silt, and poorly sorted fine to coarse,
clayey sand; 62% silt and clay; contains 2 major
clay layers the lower of which is 10-56 ft thick and
is the principal confining unit for lower aquifer
zones
Very poorly to well-sorted, medium to coarse
sands; 5% sand and clay beds; an important
production zone for water supply wells in the M-
Area
16-34 ft
32-95 ft
152-1 son
PageA2
U.S. Department of Energy
189
-------
continued
Contaminant Locations and Hydrogeologic Profiles (continued)
Metal-degreasing
solvent wastes were
sent to the A-014 outfall
and, via the process
sewer, to the M-Area
settling basin. Data
from hundreds of soil
borings, ground water
monitoring wells, and a
variety of other
Investigative techniques
have established a well-
documented VOC
plume in both the
vadose and saturated
zones.
TCE Ground Water Plume (Top View)
Data from 15 feet below water table in
the third quarter of 1990.
C3 8,000-16,000 ug/L
16,000-24,000 ug/L
24,000-32,000 ug/L
32,000 - 40,000 ug/L
40,000 - 48,000 ug/L
> 48,000 ug/L
(figure modified from Reference 6)
TCE Concentrations in Soil (West-East Cross-Section)
Concentration and lithology data from 1991 along an approximately 200-ft cross-section across the
integrated demonstration site. Concentration contours of TCE in sediments are based on analysis of over
1000 sediment samples. Highest concentrations of TCE and PCE occur in clay zones. The clay layer at
a depth of 30 to 40 feet shows high concentrations of TCE and PCE at the left end of the cross section.
Typical
Borehole
Lithology
50-
100-
uo-'
Surface
(figure modified from Reference 6)
Clay
4 Clay
Sand
Sand
Sand
Clay
Legend
soil concentrations
in ug/kg
0100 to 1,000 ug/kg |
[H 1,000 to 5,000 ug/kg j
15,000 to 10.000 units ug/kg
| >10,000 ug/kg
Page A3
U.S. Department of Energy
190
-------
APPENDIX B
PERFORMANCE DETAIL
Operational Performance
Maintainability and Reliability
• No functional problems encountered during
demonstration; system was operational
approximately 90% of all available time.
• Operational performance over long periods
(years) not yet available.
Demonstration Schedule
Operational Simplicity
• An automated system that is computer controlled
allows unattended operation. It can bemaintained
in the field typically by 1/6 full-time equivalent
technician.
Maior Milestones of the Demonstration Program
!_ 19J3 _ _°.c.*0.be.r_ _ No-v£t"b.eL DJ?£.eP.b.e-r_ Ji?4. -pa".118. 1 f**™aIL J
*rir
Sampling, Monitoring, Analysis, and QA/QC Issues
Objectives
• Gather baseline information and fully characterize site
before and after the demonstration
• Evaluate removal efficiencies with time
• Identify and evaluate zones of influence
Baseline Characterization
• Baseline characterization was performed before the demonstration to gather information on the geology and
geochemistry of the site. These data were compared with data on soil collected after the demonstration to evaluate
the effectiveness of SPSH.
• Geologic cross-sections were prepared using core logs.
• Continuous cores were collected from 2 electrode boreholes, 3 observation wells, and the extraction well.
Sediments for VOC analysis were collected at 1-ft intervals for chemical and moisture content determinations.
Analytical Methods and Equipment
• Vapor grab samples were analyzed in the field using both a Photo Vac field gas chromatograph (GC) and a GC fitted with
flame ionization and electron capture detectors. Analysis was performed immediately after collection.
• VOC analysis of sediment samples was performed daily using an improved quantitative headspace method developed by
Westinghouse Savannah River Company. Analyses were performed on an HP-5890 GC fitted with an electron capture
detector and headspace sampler.
QA/QC Issues
• Vapor samples were analyzed immediately after collection and GC analysis of soil and water
samples were completed less than 3 weeks after collection.
• GC calibration checks were run daily using samples spiked with standard solutions.
. PageBI ——
U.S. Department of Energy
191
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APPENDIX C
REFERENCES
1. Theresa Bergsman, 1995, Battelle Pacific Northwest Laboratory, personal communication.
2. Carol Eddy Dilek, 1995, Westinghouse Savannah River Company, personal communication.
3, Timothy Jarosch, 1995, Westinghouse Savannah River Company, personal communication.
4. P.A. Gauglitz, J.S. Roberts, T.M. Bergsman, R. Schalla, S.M.Caley, M.H. Schlender, W.O. Heath, T.R.Jarosch, M.C. Miller, C.A.
Eddy Dilek, R.W. Moss, B.B. Looney, 1994, Six-Phase Soil Heating for Enhanced Removal of Contaminants: Volatile Organic
Compounds in Non-Arid Soils Integrated Demonstration, Savannah River Site, PNL-10184, Battelle Pacific Northwest Laboratory,
RfchlandWA.
5. P.A. Gauglitz, J.S. Roberts, T.M. Bergsman, S.M.Caley, W.O. Heath, M.C. Miller, R.W. Moss, R. Schalla, T.R.Jarosch, C.A. Eddy
Dilek, B.B. Looney, 1994, "Six-Phase Soil Heating Accelerates VOC Extraction from Clay Soil," Proceedings of Spectrum'94, Atlanta
GA, August 1994.
6. J.P. Bremser and S.R. Booth, 1995, Cost Effectiveness of Thermally Enhanced In-Situ Soil Remediation Technologies, Los
Alamos National Laboratory, Los Alamos NM, in press.
7. C.A. Eddy Dilek, T.R. Jarosch, MAKeenan, W.H.Parker, S.P.Poppy, and J.S. Simmons, 1994, Characterization of the Geology
and Contaminant Distribution at the Six Phase Heating Demonstration Site at the Savannah River Site, WSRC-TR-93-678,
Westinghouse Savannah River Company, Aiken SC.
8. A.L Ramirez amd W.D. Daily, 1995, Monitoring Six-Phase Ohmic Heating of Contaminated Soils Using Electrical Resistance
Tomography, UCRL-ID-118418, Lawrence Livermore National Laboratory, Livermore CA.
9. W.O. Heath, 1992, Conceptual Field Test Plan: BRACE Technologies for Soil and Off-Gas Treatment, PNL-SA-21537, Battelle
Pacific Northwest Laboratory, Richland WA.
10. T.M. Bergsman, J.S. Roberts, D.L. Lessor, W.O. Heath, 1993, "Field Test of Six Phase Heating and Evaluation of Engineering
Design Cods," Presented at Waste Management Symposium 1993, Tucson AZ, February 1993.
Page C1
U.S. Department of Energy
192
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This summary was prepared by:
CKY incorporated
Environmental Services
140 E. Division Rd. Suite C-3
Oak Ridge, Tennessee, 37830
Contact: Kenneth Shepard (615) 483-4376
in conjunction with:
Stone & Webster Environmental .A
Technology & Services APv^
245 Summer Street
Boston, MA 02210
Contact: Bruno Brodfeld (617) 589-2767
Assistance was provided by the
LAWRENCE LIVERMORE NATIONAL LABORATORY
ENVIRONMENTAL TECHNOLOGY PROGRAM
EARTH SCIENCES DIVISION
which supplied key information and reviewed report drafts.
Final editing and production was provided by the
Colorado Center for Environmental Management
999 18th Street Suite 2750
Denver CO 80202
(303) 297-0180
for:
HAZARDOUS WASTE REMEDIAL ACTIONS PROGRAM
Environmental Managment and Enrichment Facilities
Oak Ridge, Tennessee 37831-7606
managed by
MARTIN MARIETTA ENERGY SYSTEMS
for the
U.S. Department of Energy
under Contract DE-AC05-84OR-21400
950R-7400-001-008
193
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OTHER IN SITU
TECHNOLOGIES
CASE STUDIES
195
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-------
Hydraulic and Pneumatic Fracturing, U.S. Department
of Energy (Portsmouth Gaseous Diffusion Plant, Ohio),
Department of Defense, and Commercial Sites
197
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Case Study Abstract
Hydraulic and Pneumatic Fracturing, U.S. Department
of Energy (Portsmouth Gaseous Diffusion Plant, Ohio),
Department of Defense, and Commercial Sites
Site Name:
1. U.S. Department of Energy
(DOE), Portsmouth Gaseous
Diffusion Plant (PGDP)
2. DoD (e.g., Tinker AFB) and
Commercial sites (various)
Location:
Piketon, Ohio (for PGDP)
Contaminants:
- Demonstrations conducted at sites
contaminated with Volatile Organic
Contaminants (VOCs) (including
Trichloroethene (TCE)), Dense
Nonaqueous Phase Liquids (DNAPLs), and
at uncontaminated sites
Period of Operation:
July 1991 - August 1996
(multiple demos during this
time period)
Cleanup Type:
Field demonstration
Technical Information:
Pneumatic: J. Liskowitz/T. Keffer,
ARS, (908) 739-6444
John Schuring, NJIT, (201) 596-5849
Hydraulic L. Murdoch, Univ. of
Cine., (513) 556-2519
W. Slack, ERX, (513) 556-2526
R. Sicgrist, ORNL, Col. Sch. of
Mines, (303) 273-3490
SIC Code:
9711 (National Security)
Others - information not provided
Technology:
Hydraulic and Pneumatic Fracturing
- Hydraulic fracturing equipment includes
lance, notch tool, slurry mixer, and pump
- Gel-laden proppant is pumped into notch
under 60 psig to create a fracture
- Pneumatic fracturing equipment includes
high-pressure air source, pressure regulator,
and receiver tank with inline flow meter
and pressure gauge
- Air is injected at 72.5-290 psi for <30
seconds using a proprietary nozzle
- Design considerations include formation
permeability, type, and structure; sand
proppant; state of stress; site conditions;
and depth „
- Fracturing used in conjunction with other
in situ technologies such as SVE,
bioremediation, and pump and treat
Cleanup Authority:
Information not provided
Points of Contact:
Skip Chamberlain, DOE,
(301) 903-7248
James Wright, DOE,
(803) 725-5608
Waste Source:
Tinker - Underground Storage Tank
Others - Information not provided
Purpose/Significance of
Application:
Demonstrations of technology used
to increase hydraulic conductivity,
contaminant mass recovery, and
radius of influence (for example, in
a SVE application)
Type/Quantity of Media Treated:
Soil and Ground Water
- Generally applicable in low permeability formations
- At PGDP, was used at uncontaminated site underlain by low permeability
clays and silts to a depth of approximately 15-22 ft
Regulatory Requirements/Cleanup Goals:
- No special permits were required for use in the demonstrations
- Some states may be concerned about injection of fluids and other materials that may alter the pH of the subsurface
198
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Case Study Abstract
Hydraulic and Pneumatic Fracturing, U.S. Department
of Energy (Portsmouth Gaseous Diffusion Plant, Ohio),
Department of Defense, and Commercial Sites (Continued)
Results:
- Hydraulic fracturing demonstrations showed mass recovery increased from 2.8-50 times, and radius of influence from
25-30 times
- Pneumatic fracturing at Tinker Air Force Base increased product thickness in recovery well from 1.5 to 20.2 ft
- Pneumatic fracturing at PGDP doubled hydraulic conductivity, and increased radius of influence by 33% after one day
of pumping
Cost Factors:
- Capital and annual costs not provided for demonstrations
- Hydraulic fracturing projected to cost $5,400 for one-time costs, and $5,700 for daily costs (corresponding to $950-
1,425 per fracture, for 4-6 fractures)
- Pneumatic fracturing projected to be similar to those for hydraulic fracturing ($400-1,425 per fracture)
- Pneumatic fracturing at a SITE demonstration estimated at $140/lb of TCE removed; other estimates predict
pneumatic fracturing cost of $8-17/yd3 soil treated
Description:
Hydraulic and pneumatic fracturing are technologies that can enhance access to the subsurface for remediation of
contaminants above and below the water table. Enhanced access is provided by creating new or enlarging existing
fractures in the subsurface. These fractures enhance the performance of in situ remediation technologies such as SVE,
bioremediation, and pump and treat by increasing the soil permeability; increasing the effective radius of recovery or
injection wells; increasing potential contact area with contaminated soils; and intersecting natural features. Fracturing
can also be used to improve delivery of materials to the subsurface (e.g., nutrients).
A number of demonstrations of hydraulic and pneumatic fracturing have been conducted to show technology
applicability and performance in a variety of settings. Hydraulic fracturing demonstrations have showed mass recovery
increases from 2.8-50 times, and radius of influence increases from 25-30 times. Pneumatic fracturing demonstrations
have been conducted at Tinker Air Force Base and PGDP, with results provided in terms of increased product thickness
in recovery wells and increases in hydraulic conductivity and radius of influence. Hydraulic fracturing is commercially
available from several companies, while pneumatic fracturing has been patented by the New Jersey Institute of
Technology (NJIT). The NJIT has licensed pneumatic fracturing to Accutech Remedial Services (ARS). While
hydraulic fracturing produces larger apertures and can be performed at greater depths than pneumatic fracturing, the
addition of water in hydraulic fracturing may create a larger volume of contaminated media possibly requiring
remediation. Prior to proposing fracturing, sites should be analyzed for permeability. Sites with extensively fractured
strata will have permeabilities that are high enough that fracturing may not be required.
199
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SECTION 1
SUMMARY
Technology Description
Hydraulic and Pneumatic Fracturing are two technologies that can enhance access to the subsurface for remediation of contami-
nants both above and below the water table.
• Enhanced access is provided by creating new or enlarging existing fractures in the subsurface to improve fluid flow to
encourage removal or treatment of contaminants.
• The innovation adapts a petroleum recovery technique to the environmental field. Fracturing can then be combined with
other innovative technologies to provide an effective remediation system at difficult sites.
Induced fractures enhance the performance of in situ remediation technologies in low-permeability strata by
• increasing the permeability of the soil,
• increasing the effective radius of recovery or injection wells,
• increasing potential contact area with contaminated soils,
* intersecting natural fractures.
Better extraction of contaminants from or delivery of materials (gases, liquids, or solids) to the subsurface can produce a more
effective in situ remediation. Examples of innovative materials that can be introduced through fractures include:
0 Nutrients or slowly dissolving oxygen sources to improve bioremediation processes;
0 Electrically conductive compounds (e.g., graphite) to improve electrokinetic processes;
0 Rcactant materials such as zero-valent iron or permanganate.
These technologies are particularly useful at contaminated sites with low-permeability soil and geologic media, such as clays,
shales, and tight sandstones. However fracturing technology is not limited to low-permeability sites.
Fluid Pressure Surgt
Advantages of
Fracturing
Increased fluid
flow/access
Multiple Fractures
Created/Enlarged
NAPL Pockets
Accessed
Fewer Wells
Figure 1. Fracturing of Low-Permeability Formation. Extraction/treatment can be
accomplished either in the fluid injection borehole or in adjacent boreholes.
Fractures are typically created in a horizontal or subhorizontal plane at specific horizons (<2 feet) by injecting a fluid
(cither liquid or gaseous) into a sealed borehole until the pressure exceeds a critical value, thus nucleating a fracture.
After injection is complete, fractures are held open naturally or with an introduced proppant, a material injected to "prop"
open the fractures. If a liquid (e.g. guar gum gel) is used to create the fracture, a granular proppant can be introduced to
assist with maintenance of fracture openings.
The direction of fracture propagation is controlled by the state of stress in the subsurface. Sites with horizontal stress
greater than vertical stress will produce horizontal or subhorizontal fractures. These sites typically consist of overconsoli-
dated fine-grained deposits (silts and clays). For Pneumatic Fracturing a directional nozzle can be used to control the
direction of fracture propagation.
Creation of fractures does not add significant up-front costs (up to a few percent) to an overall remediation system and it
may provide significant reduction in the life-cycle costs to remediate a site because fewer wells may be required and
cleanup may be accomplished more rapidly.
Pagel
U.S. Department of Energy
200
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Technology Status
• Hydraulic Fracturing has been extensively researched and used in the petroleum industry for over 50 years. It has required
modification for use in the environmental field. Since the early 1990's, research has been conducted on the viability of
both Pneumatic and Hydraulic Fracturing for environmental applications.
• A number of demonstrations of Hydraulic and Pneumatic Fracturing have been conducted to show their applicability to
the environmental field. Both technologies were demonstrated under the EPA SITE program in the early 1990's.
Technology Evaluation and Applications Analysis Reports are available for both technologies (see references).
• Bench-scale tests, followed by pilot- and field-scale tests on both clean and contaminated sites, have been conducted by
NJIT and ARS using Pneumatic Fracturing. Terra Vac, Malcolm Pirnie, and others have also participated in Pneumatic
Fracturing projects. The U.S. Department of Energy (DOE) has supported several demonstrations of Pneumatic
Fracturing, including one at Tinker Air Force Base and one at the DOE Portsmouth Gaseous Diffusion Plant. New Jersey
Institute of Technology (NJIT) patented Pneumatic Fracturing for environmental applications. In 1992 they licensed the
technology to Accutech Remedial Systems (ARS).
• FRX in cooperation with the University of Cincinnati has conducted pilot and field scale tests of hydraulic fracturing on
both clean and contaminated sites in 9 states and Canada (TX, OH, ID, EL, CT, ME, MI, NJ, CO). Colder Associates has
conducted bench, pilot and field scale tests concentrating on hydraulic fracturing. A hydraulic fracturing demonstration
has been completed at the DOE Portsmouth Gaseous Diffusion Plant. Future development will include coupling of in situ
mass transfer and destruction processes. Advanced applications such as injection of graphite, iron filings, oxidants and
activated carbon were tested.
• Key Results
• Hydraulic and Pneumatic Fracturing at geologically appropriate sites have significantly improved recovery of contaminated
fluids (-10 to >1000 times). These technologies typically have generated fractures that significantly increase the radius of
influence for vertical recovery wells at the sites (10-fold).
0 Hydraulically developed fractures were demonstrated to be effective for a period of more than one year. Vapor flow
rates were increased by 15 to 30 times that of unfractured wells. Water flow rates were increased by 25 to 40 times that
of unfractured wells.
• Hydraulic and Pneumatic Fracturing have been used in conjunction with soil vapor extraction, pump and treat, bioremedi-
ation, free product recovery, and in situ vilification at contaminated sites. Demonstrations of other applications, such as
passive chemical barriers or electrokinetics, are underway.
• Hydraulic Fracturing is commercially available from several companies: FRX, Inc., Colder Associates Ltd., Hay ward
Baker Environmental, Inc., and perhaps others. Larger scale, more costly applications are performed by several companies
for oilfield applications. Pneumatic Fracturing is commercially available from ARS. ARS has used Pneumatic Fracturing
at over 30 sites in North America. ARS has recently signed an agreement with DOWA Mining Company LTD of Japan to
market Pneumatic Fracturing in Japan.
CONTACTS
Technical/
Pneumatic
John Liskowitz/Ted Keffer, Accutech Remedial Systems, Inc., Keyport, NJ (908) 739-6444
John Schilling, New Jersey Institute of Technology, Newark, NJ (201) 596-5849
Hydraulic
Larry Murdoch, University of Cincinnati, Cincinnati, OH (513) 556-2519
William Slack, FRX, Inc. Cincinnati, OH (513) 556-2526
Robert Siegrist, Oak Ridge National Laboratory, Colorado School of Mines, Golden, CO (303) 273-3490
Management
Skip Chamberlain, DOE EM50, Garthersburg, MD (301) 903-7248
James Wright, DOE Savannah River, Aiken, SC (803) 725-5608
(Information in this report is based on technologies as implemented by ARS and FRX.)
—— Page 2 - « =
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U.S. Department of Energy
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SECTION 2
TECHNOLOGY DESCRIPTION
I Process Schematic
Hydraulic Fracturing
Rod
d.
Figure 3. Hydraulic Fracturing Schematic (from U.S. EPA, 1994)
Equipment
• The fracturing equipment consists of a lance, a tool to create an initial notch, a continuous slurry mixer, a positive
displacement pump mounted on a trailer, and the fracture mixture (fluid and proppant).
Process
• A well is drilled and cased down to the depth where fractures are desired in lithified sediments (in unlithified sediments
a straddle-packer system is used). A rod with a cone-shaped end, the lance, is introduced into the bottom of the borehole
and is driven to the depth at which the fracture is desired. The lance tip remains in the soil whereas the lance is later"
removed from the borehole.
• A water jet (steel tubing with a narrow orifice at one end) is inserted into the cone-shaped rod, water is pumped through
the tubing to create a high-pressure water jet (pressure 3500 psi). The jet is rotated within the borehole to create a disc-
shaped horizontal notch extending 4 to 6 inches from the borehole.
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U.S. Department of Energy
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TECHNOLOGY DESCRIPTION
continued
The gel-laden proppant is then pumped into the notch under relatively low pressures (60 psig) to create a fracture. Lateral
pressure from the soil on the outer wall of the casing effectively seals the casing and prevents leakage of the slurry. The
fracture nucleates at the notch and grows radially up to about 20 feet from the borehole wall. The gel to sand ratio is
adjusted from fracture to fracture, depending on depth and site-specific soil conditions.
Pneumatic Fracturing
I
Previously
Fractured
Zone
Unfractured
Soil
Figure 4. Schematic of Pneumatic Fracturing Process
Equipment
• The fracturing equipment consists of a high-pressure air source (e.g., compressed gas cylinders) with pressure regulator,
and a receiver tank attached to a pipe with an inline flow meter and pressure gauge.
Process
• An uncased or cased well is drilled. A small vertical section of the well (up to two feet) is isolated, then high-pressure air
is injected for short periods of time (< 30 seconds) using a proprietary nozzle. Air is injected at rates of 25 to 50 cubic
meters (883 to 1,766 cubic feet) per minute at pressures of 0.5 to 2MPa (72.5 to 290 psi).
• The isolation and injection are repeated at the desired vertical intervals.
General Considerations
The direction of fracture propagation will be perpendicular to the minimum principal stress in the subsurface at a particu-
lar site. Recent field data indicate that soil fabric or lithology may have a greater influence on fracture orientation than the
in situ state of stress in the soil mass in some soil deposits.
Injection pressure required to initiate a fracture generally increases with increasing depth, injection rate, and fluid viscosity.
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U.S. Department of Energy
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TECHNOLOGY DESCRIPTION
continued
Plan
Section
Figure 2. Plan and section of a typical hydraulic fracture created in overconsolidated silty clay.
(modified from U.S. EPA, 1994).
Injection Fluids
Guar gum gel is commonly used in hydraulic fracturing. The gel carries sand into the subsurface to prop the fractures open.
0 Guar gum is a food additive and when mixed with water forms a short-chain polymer with the consistency of molasses.
0 A crosslinker is added to lengthen the polymer chains and create a thick gel capable of suspending high concentrations of sand.
0 An enzyme is added to the gel that breaks down the polymer chains in a few hours to allow recovery of the thinned liquid.
• Pneumatic Fracturing (i.e., injection of air) typically uses no propping agents and is thus best applied at sites where the
geology is conducive to maintaining open any dilated existing fractures or newly created fractures.
Leakoff
• Leakoff occurs when some of the injected fluid flows out through the walls of the fracture. The rate of fracture propaga-
tion decreases as the rate of leakoff increases, and propagation ceases entirely when the leakoff rate equals the rate of
injection.
• Leakoff generally controls the size of the fractures. Leakoff is minimized by controlling amount and rate of injection.
Monitoring Fracture Location
• The most widely used method of monitoring fracture location is measuring the displacement of the ground surface,
using either surveying of field staffs before and after or tiltmeters during fracture propagation. Pressure influence in
surrounding monitoring wells can also be measured to determine fracture locations.
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TECHNOLOGY DESCRIPTION
continued
Design Considerations
The table below summarizes the factors that should be considered when deciding if a site is appropriate for fracturing and if so
how to best design the project (modified from US EPA, 1994).
Factor
Favorable
Unfavorable
Formation permeability Moderate to low(k <10~6 cm2)
Formation type
Formation structure
Sand proppant
State of stress
Site conditions
Depth
Rock or fine-grained sediment
Horizontal bedding planes
Unlithified, saturated sediments
Horizontal stress > vertical
stress (overconsolidated)
Open ground over fracture/
no buried utilities
One to eight meters
Unnecessary in high permeability formations
Coarse-grained sediment
Vertical structures
May be unnecessary in consolidated units
Horizontal stress < vertical stress
(normally consolidated)
Structures sensitive to displacement over fracture/
buried utilities
Surface or > eight meters
Page 6
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U.S. Department of Energy
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SECTION 3
PERFORMANCE
Demonstration Plan E
Major elements of the demonstrations included:
• Initial flow rates and contaminant extraction levels from extraction and monitoring wells (monitoring wells sampled
to determine whether fractures have established connections between the fracture well and the monitoring wells.)
• Final flow rates and contaminant extraction levels from extraction and monitoring wells;
• Pressures at both monitoring wells and extraction wells.
Specific examples of demonstrations for each of the technologies, with focus on those supported by DOE, are presented in this
section.
• Demonstration Summary ^^^^^^^^—^~^^^—^^^^^—m—^^^—i
Hydraulic Fracturing
• Hydraulic fracturing was demonstrated under the EPA SITE program in July of 1991 at sites in Oak Brook Illinois and
Dayton Ohio. Both sites contained low-permeability soils (<10~7 cm/sec) that were contaminated with volatile organic
compounds (VOCs). Fracturing was accomplished to a depth of 15 feet below ground surface.
0 In Illinois, contaminants removed by soil vapor extraction were increased by 7 to 14 times and the area of influence
was 30 times greater after fracturing.
0 In Ohio flow of water into the fractured well was increased 25 to 40 times and bioremediation rate was increased by
approximately 75%.
• Demonstrations have also been conducted at the DOE Portsmouth Gaseous Diffusion Plant (August 1996), the Laidlaw
site near Sarnia, Ontario, Canada (cofunded by DOE), the Bristol Tennessee site, the Beaumont Texas site, and the
Linemaster Switch Superfund Site in Woodstock Connecticut. At the DOE site, fractures were propped with sand, oxi-
dants, and reductants; the site was then treated with hot air/steam enhanced air flushing and in situ chemical degradation.
Pneumatic Fracturing
• An EPA SITE demonstration was conducted at a site in Hillsborough, New Jersey in 1992. Fractures created during the
demonstration significantly increased the effective radius of influence and increased the rate of mass removal about 675%
over the rates measured before fracturing. By installing wells to be used as passive inlets/outlets, improvements in mass
removal rates were as high as 2300%.
• DOE supported demonstration at the Tinker Air Force Base in Oklahoma and the Portsmouth Gaseous Diffusion Plant
in Ohio.
Treatment Performance
Hydraulic Fracturing:
Site 1 - Laidlaw Site, Sarnia, Ontario
• The sheet-pile test cell was a clean site located adjacent to a major hazardous waste landfill. A synthetic gasoline blend
with a tracer of trichloroethylene (TCE) was released into the cell in 1992. Soil vapor extraction was then initiated.
Surface materials at this location are composed of clay-rich glacial till.
• In August of 1994, hydraulic fracturing was conducted. Fifteen fractures were emplaced at 9 locations outside of the
sheet-pile cell at depths of 1.2 and 5.6 meters. .
0 Minimum surface uplift from the fracturing was observed as 1 to 4.65 centimeters.
0 More symmetric fractures were created at shallow depths, while asymmetric fractures were created at depths greater
than 2.5 meters. In addition, the dip of the fractures increased with the depth of the fracture, if greater than 2.5 meters.
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U.S. Department of Energy
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PERFORMANCE
continued
Other Sites
• Performance of wells that have been hydraulically fractured generally increases by a factor of 1.5 to 10 but the range
varies up to 100 or more.
• Several examples of demonstration performance are listed below.
Site Name
Contaminant/Geology Mass Recovery Change Radius of Influence Improvement
Oak Brook IL
Dayton OH
Bristol TN
Regina Saskatchewan
Calgary Alberta
Linemaster, CT
Beaumont TX
VOCs in Silty Clay
VOCs in Silty Clay
DNAPL/Fract. Bedrk.
VOCs in Silty Clay
VOCs in Silty Clay
Solvents in Till
DNAPL in Silty Clay
7 to 14
25 to 40
2.8 to 6.2
10
4 to 6
50
30 times
30 times
25
-25
Pneumatic Fracturing:
Site 1- Fuel Oil In Sedimentary Strata: Tinker Air Force Base, Oklahoma
• Fuel oil had leaked from an underground storage tank into interbedded sedimentary strata. A pump and treat system was
installed and recovered 155 gallons per month for 17 months.
• Four wells were installed at the site and pneumatically fractured.
• Key results were:
0 After installation of the first fractured well, fuel oil (as floating product) thickness in the nearby recovery well increased
from 1.5 feet to 20.2 feet (see figure below) and oil recovery increased to approximately 435 gallons per month.
0 Other fracture wells improved performance from other recovery wells from 224 to 434%.
0 Oil production was increased in wells as far as 59 feet from the injection point.
0 Oil recovered as a percentage of total fluid pumped increased from 12 to 90%.
• Fracture wells were also installed at an adjacent site to enhance bioremediation in a clayey silt and sand formation.
Air flows from vapor extraction increased 500 to 1700%.
Product Thickness (prefracture)
Product Thickness (postfracture)
fta* Foltawftis Pumping (Houra)
Figure 5. Floating Product (fuel oil) Thickness Data for Recovery Well 4
Site 2- VOCs and DNAPLs in silts and clays: DOE Portsmouth Gaseous Diffusion Plant, Ohio
• The Clean Test Site (CTS) is underlain by low-permeability clays and silts to a depth of approximately 15 to 22 feet.
During the summer of 1994, two fracture wells were created. Post-fracture hydraulic conductivity was determined to be 1.0
feet/day, a two-fold increase with a radius of influence increasing by 33% from 200 to 300 feet after one day of pumping.
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U.S. Department of Energy
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SECTION 4
TECHNOLOGY APPLICABILITY AND ALTERNATIVE TECHNOLOGIES
Technology Applicability
• Fracturing enhances current remediation technologies by increasing permeabilities and improving flow, recovery and
destruction rates for.
0 vapor extraction,
0 ground water extraction,
0 bioremediation,
0 free product recovery (LNAPLs and DNAPLs),
0 possibly electrokinetics and other innovative in situ technologies, such as permeable barriers with chemical oxidants or
reductants.
• Hydraulic and Pneumatic Fracturing for fluid recovery enhancement have been successfully demonstrated on the field
scale in both the vadose and
saturated zones.
• Hydraulic and Pneumatic Fracturing are well suited for sites with an assortment of underlying strata, especially such as
low-permeability sandstones, clays, siltstones, and shales.
Competing Technologies
The baseline against which fracturing can be compared is remediation, such as soil vapor extraction, without fracturing. Improvements
in recovery of contaminants after fracturing can then be used to compare to the baseline.
Hydraulic and Pneumatic Fracturing are competing technologies. A site being considered for fracturing must be evaluated to
determine which technology would perform as required and be the most cost effective. A table comparing the two technologies
is presented in Appendix B (from Keffer et al., 1996).
Another technology designed to enhance access to the subsurface is that of directionally drilled horizontal wells. Fracturing of
geologic media and soils at low-permeability sites contaminated with VOCs also competes with soil heating technologies,
designed to enhance contaminant removal by soil vapor extraction (see Six Phase Soil Heating ITSR report, DOE, 1995, as an
example.) In situ enhanced soil mixing has been used to treat VOC-contaminated sites with low-permeability soils and geologic
media (sec ITSR In Situ Enhanced Soil Mixing, DOE, 1996). Other remediation technologies such as surfactant flushing and
bioremediation do not compete directly as they do not enhance access to the subsurface.
Technology Maturity
Hydraulic Fracturing
• Hydraulic Fracturing has been used extensively for over fifty years in the petroleum industry. It has been demonstrated
at a number of sites in North America for fluid recovery enhancement but not yet fully implemented for a site cleanup.
Advanced applications of fracturing technology represent an earlier stage of development.
Pneumatic Fracturing
• Pneumatic Fracturing has been demonstrated at over thirty sites in North America and has been utilized for full imple-
mentation of site cleanup at six or more sites.
Page 9
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SECTION 5
COST
Hydraulic Fracturing
The EPA has reported the cost per single fracture ranging from $950-$ 1425, however the cost is highly dependent upon the
number of fractures to be placed in each borehole. EPA also reported a daily cost of $5700 to create 4 to 6 fractures. Colder
Associates Ltd. reports costs of $400-500 per fracture or $2000 to $6000 per well.
Type of Cost
Site Preparation
Permitting and Regulatory
Capital Equipment Rental
Startup
Labor
Supply and Consumables
Utilities
Effluent Treatment and Disposal
Residual and Waste Shipping and Handling
Analytical and Monitoring
Maintenance and Modifications
Demobilization
Total One-Time Costs
Total Daily Costs
Estimated Cost per Fracture
Dsuly Cost ($)
1,000
5,000
1,000
0
2,000
1,000
0
0
0
700
0
400
5,400
5,700
950-1425
Source: U.S. EPA 1993a.
Pneumatic Fracturing
d
Pneumatic Fracturing costs can be estimated to be similar to those of Hydraulic Fracturing reported above, $400-1425 per
fracture. However, an alternative cost estimating method, based upon dollars per pound of contaminant removed, was completed
by EPA. Costs calculated for the EPA SITE demonstration in New Jersey were estimated at $140/lb of TCE removed for a
hypothetical remediation, assuming constant removal rate:
• site = 100 feet by 150 feet
• effective radius of influence 25 feet
• 15 wells required to get a 15-20% overlap
• one-year operating cycle with capital cost amortization.
Costs were extrapolated from a 4-hour postfracture test:
• labor 29%
• capital equipment 22%
• offgas treatment 19%
• site preparation 11%
• residuals disposal 10%
Other estimates predict Pneumatic Fracturing to cost $8 to $17 per cubic yard of soil treated. Fracturing can be completed using
a weekly rate of $ 15,000 to $20,000.
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SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations ^^^^••••••••••^^^^•^^^^^•^^^^••^^^^^•••••y
To date, no special permits are required for the use of Pneumatic or Hydraulic Fracturing. Fracturing activities are consid-
ered under the requirements for the remediation of a particular site.
0 Gels used in Hydraulic Fracturing (usually guar gum) are biodegradable and non-toxic. Other additives, such as the
proppants (usually sand of various grain sizes) and water, are naturally occurring and not a regulatory concern.
0 However, some state agencies are concerned about injection of fluids and materials that may alter the pH of the subsurface.
A possible concern is the lack of control of fracture generation.
0 Behavior of a strata prior to fracture, such as the quantity, size and direction of the generated fractures, is not well-
defined. Information on site geology/hydrology can be used to model the placement of fractures.
0 In a highly fractured system, further fracturing may drive contamination away from the pressure front, thus increasing
the area of contamination.
Safety, Risks, Benefits, and Community Reaction
Worker Safety
* Health and safety issues for fracturing technologies do not present significant hazards over conventional field remediation
operations.
• Pressures used are high enough to require extreme caution. All equipment is checked regularly and contains safety fea-
tures such as pressure relief valves. All workers are trained regularly in safe equipment operation and are required to take
OSHA 40-hour training. An addendum to the Health and Safety Plan addressing pressure issues would typically be
required.
Community Safety
• Fracturing technologies do not produce any routine release of contaminants.
• No unusual safety concerns are associated with the transport of equipment to and from the site.
• Careful monitoring of field operations assures safety to the workers and the public.
Environmental Impacts
• No additional impacts will be produced over that already underway as a result of the site remediation efforts. Equipment
is transported to the site and then removed after the fractures are created.
Socioeconomic Impacts and Community Perception
* Fracturing has a minimal economic or labor force impact.
* The general public has limited familiarity with this technology.
Page 11
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SECTION 7
LESSONS LEARNED
Implementation Considerations
• The precise geometry (direction, length and size) of fractures cannot be determined prior to generation, but likely characteris-
tics can be generalized by experienced practitioners based on site conditions and experience.
• Sites should be analyzed for permeability before fracturing is proposed. Extensively fractured strata will have permeabilities
high enough such that they will not require fracturing and fracturing will not be optimal as the pressure required to fracture
the strata further may be much larger than the operating range of the injection equipment (i.e too much leakoff occurs).
• Perched water may hamper measurement of the extent of fracturing or interfere with the remediation system performance
for vadose-zone soil vapor extraction systems.
Technology Limitations and Need for Future Development
• Fracturing for ambient temperature fluid recovery has been demonstrated at many sites; existing and future development
includes coupling of in situ mass transfer and destruction processes.
• The degree of post-emplacement healing of fractures (especially with unpropped fractures) and the degree of pore continuity
disruption furing operation are not well documented at this time.
• Fracturing near foundations or utilities should include a risk analysis before the fracturing is initiated, as strata upheaval
may weaken supports and crack foundations and utilities. The utilities or foundations may also act as preferential pathways,
thus limiting fracture generation. However, many sites in the vicinity of utilities and foundations have been fractured
without significant problems.
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APPENDIX A
REFERENCES
American Petroleum Institute, 1995, Petroleum Contaminated Low Permeability Soil: Hydrocarbon Distribution Processes, Exposure
Pathways and In Situ Remediation Technologies. Health and Environmental Sciences Dept. Publication No. 4631. September 1995.
Anderson, D.B., BM. Peyton, J.L. Liskowitz, C. Fitzgerald, J.R. Schuring, 1994, Enhancing In-Situ Bioremediation with
Pneumatic Fracturing, In-Situ and On-Site Bioreclamation: The Third International Symposium Proceedings, April 24 - 27,
1994, San Diego, CA. PNL-SA-24717.
Baker, E. and B. Leach, 1995, Soil Fracturing Cracks Soil Remediation Barriers, Environmental Solutions, March 1995, p. 26-27.
Frank, U., 1994, U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation of Pneumatic Fracturing
Extraction, Jour. Air Waste Management, v. 44, # 10, p. 1219-1223.
Keffer, E.B., JJ. Liskowitz, and C.D. Fitzgerald, 1996, The Effect of Pneumatic Fracturing When Applied to Ground Water
Aquifers, Sixth West Coast Conference on Contaminated Soil and Ground Water, March 1996.
Leach, B., 1995, New tool fractures subsurface in one step, Soils, January-February 1995.
Mack, J.P. and H.N. Apsan, 1993, Using Pneumatic Fracturing Extraction to Achieve Regulatory Compliance and Enhance VOC
Removal from Low Permeability Formations, Remediation, v. 3, # 7, p. 309-326.
Maekie, M.E. and S.B. Gelb, 1993, Characterization and Impact of Local Hydrogeologic Conditions at a Chlorinated Solvent
DNAPL Site in Central New Jersey, Jour. Env. Health, v. 56, # 3, p. 842-843.
Schuring, J.R., V. Jurka, P.C. Chan, 1992, Pneumatic Fracturing to Remove VOCs, Remediation, Winter 1991/92. p. 51 - 68.
Schuring, J.R., P.C. Chan, TM. Boland, 1995, Using Pneumatic Fracturing for In-Situ Remediation of Contaminated Sites,
Remediation, v. 5, # 2, p. 77-90.
Schuring, J. R. and P.C. Chan, 1992, Removal of Contaminants from the Vadose Zone by Pneumatic Fracturing, New Jersey
Institute of Technology, Newark, New Jersey. Prepared for the U.S. Geological Survey. PB92-161207.
Siegrist R.L., N.E. Korte, M.T. Muck, D.R. Smuin, A.D. Laase, O.R. West, D.T. Davenport, and J. Walker, 1995, Field Evaluation
of Subsurface Manipulation by Fracturing, Permeation Dispersal, and Horizontal Well Recirculation Using Unconfined Test Cells.
Invited presentation at the National Ground Water Association Annual Educational Conference, October, 1995, Indianapolis, IN.
Siegrist, RJL and K.S. Lowe, 1995, In Situ Remediation of DNAPL Compounds in Low Permeability Media: A Joint Initiative of the
DOE and American Petroleum Industry (Interim Report), Oak Ridge National Laboratory, Tennessee and Grand Junction Colorado.
U.S. DOE, 1994, Innovation Investment Area - Technology Summary, DOE/EM-0146P, 231 pp.
U.S. DOE, 1995, Six Phase Soil Heating - Innovative Technology Summary Report, DOE/EM-O272.
U.S. DOE, 1996, In Situ Enhanced Soil Mixing - Innovative Technology Summary Report, DOE/EM-O289
U.S. DOE, 1996, In Situ Remediation of DNAPL Compounds in Low Permeability Media: Transport/Fate, Treatment, and Risk
Reduction. Joint project report containing 16 focus papers authored by national experts. U.S. Department of Energy, Office of
Science and Technology (In press).
U.S. EPA, 1995, In Situ Remediation Technology Status Report: Hydraulic and Pneumatic Fracturing, EPA/542/K-94/005.
US. EPA, 1994, Alternative Methods for Fluid Delivery and Recovery, Office of Research and Development, EPA/625/R94/003,87 pp.
U.S. EPA, 1993a, Hydraulic Fracturing Technology, Application Analysis and Technology Evaluation Report, EPA/540/R-93/505.
U.S. EPA, 1993b, Accutech Pneumatic Fracturing Extraction and Hot Gas Injection, Phase 1, Applications Analysis Report,
EPA/540/AR-93/509.
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APPENDIX B
Comparison of Pneumatic Fracturing and Hydraulic Fracturing
(Modified from Keffer et al., 1996)
PNEUMATIC FRACTURING
Fracture apertures are small (usually measured after settling)
on the order of 500 -1,000 microns. The smaller openings cre-
ate a lower cumulative heave, which could reduce or eliminate
the long-term impact to structures.
The flow through these fractures is conductive and the lack
of a proppant allows flow to be governed by the "cubic law,"
which states that the flow rate is proportional to the cube
of the aperture opening allowing high flow rates through
smaller openings.
The fluid used to fracture is air. This creates a cleaner operation
where the volume of contaminated media is not increased,
allows better control of fracture propagation and reduces the
possibility of a hazardous waste spill due to back pressure
venting through the fracture well. Air is also less expensive
to produce.
The orientation of pneumatic fractures in soil formations is
more consistently horizontal. Some upward migration occurs
at the outer edges of shallow fractures.
Pneumatic fractures propagate between 20 and 50 feet
outward. The farthest has been 70 feet.
Pneumatic fractures are best emplaced less than 75 feet. Below
75 feet the weight of the overburden decreases the effect of
self-propping. Engineering adjustments also need to take place
below this depth.
Fracture density occurs as both a dense network of micro-
fractures that impact a smaller area around the fracture point
and a few major fractures which migrate outward into the
formation. This density occurs in each interval of 2 - 3 feet.
HYDRAULIC FRACTURING
Fracture apertures are large, usually on the order of 1 - 2 cen-
timeters. The use of proppants in these fractures translates to a
significant amount of cumulative heave, which can have a
direct impact on nearby structures, but which also can further
increase permeability.
The flow through the fractures is Darcian in nature. Thus a
larger aperture opening is required to achieve equivalent flow
rates.
The fluid used is usually water which can contact the waste
product and dissolves into the water creating a larger volume
of contaminated media. When the operation is complete, back
pressures can eject hazardous waste to the surface making a
dirty operation and possibly a reportable spill. Water intro-
duced to a vadose zone needs to be removed.
Fracture orientation has been demonstrated to have a vertical
component which often creates an angular fracture that
intersects the surface.
Hydraulic fractures propagate between 15 and 50 feet outward.
The depths at which hydraulic fractures can be emplaced
are significantly higher than the depths Pneumatic Fractures
can be emplaced.
Fracture density is typically limited to one or two major
fractures per injection interval. The injection interval is larger
varying between 5 and 20 feet.
Pneumatic Fracturing is faster. Injections typically last 20 seconds. Hydraulic fracturing typically takes 5 to 10 minutes per fracture.
Page 14
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U.S. Department of Energy
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This report was prepared by:
Colorado Center
for
Environmental Management
999 18th Street, Suite 2750
Denver, Colorado 80202
Contact: Dawn Kaback
(303) 297-0180 Ext. 111
in conjunction with:
Rust Geotech
Grand Junction, CO
Gerald Daub
(970) 248-6566
and
Hazardous Waste Remedial Actions Program
Lockheed Martin Energy Systems
P.O. Box 2003
Oak Ridge, Tennessee 37831-7606
Randall Snipes/Scott Colburn
(615) 435-31287(615) 435-3470
Assistance was provided by
Oak Ridge National Laboratory
Accutech Remedial Systems
214
-------
Frozen Soil Barrier Technology at the SEG Facilities,
Oak Ridge, Tennessee in Cooperation with U.S. Department
of Energy Oak Ridge Operations
215
-------
Case Study Abstract
Frozen Soil Barrier Technology at the SEG Facilities, Oak Ridge,
Tennessee in Cooperation with U.S. Department of Energy
Oak Ridge Operations
Site Name:
Scientific Ecology Group (SEG),
Gallaher Road Facility
Location:
Oak Ridge, Tennessee
Contaminants:
None
- Surrogate solution (200 ppm Rhodamine-
WT) were used to test the integrity
characteristics of the barrier.
Period of Operation:
May 12 - October 10, 1994
Cleanup Type:
Field demonstration
Technical Information:
Rick Swalzcll, Prin. Inv., Martin
Marietta Energy Systems, Inc.
(615) 435-3126
Ray Peters, SEG
(615) 376-8194
SIC Code:
Not Applicable (not a contaminated
site)
Technology:
Frozen Soil Barrier
- Uses refrigeration to freeze soils and
provide barrier/containment for hazardous
and/or radioactive contaminants in soil and
ground water.
- Demonstration facility was "V-shaped,
with dimensions of 56 by 56 feet outside
and 33 by 33 feet inside; maximum depth
was 28 feet;
- Refrigerant pipes were installed around
circumference of faculty in a double-rowed
configuration with an ice wall allowed to
grow together between the pipes and
forming a barrier.
Cleanup Authority:
None - demonstration
conducted at a nonhazardous
site
Management Information:
Jef Walker, DOE EM-50
Plumes Focus Area Program
Manager, (303) 903-7966
Waste Source:
Not Applicable (not a contaminated
Site)
Purpose/Significance of
Application:
Frozen soil barrier technology has
been demonstrated for controlling
waste migration in soils.
Type/Quantity of Media Treated:
Soil
- Subsurface soils consisted of 13 to 22 feet of fill soils overlying residual soils.
Fill soils consisted of stiff to hard red-brown silty clay, with varying amounts of
chert fragments. Residual soils consisted of stiff to soft red-brown to brown
silty clay and clayey silt, with varying amounts of chert fragments.
- SoU density measured as 108.8 lb/ft3.
- Average soil moisture content ranged from 26.5 to 33.9%.
- 8,175 cubic feet of soil contained by the frozen barrier.
- 35,694 cubic feet of soil composed frozen barrier.
Regulatory Requirements/Cleanup Goals:
No regulatory requirements or cleanup goals were identified for this demonstration because it was conducted at a
nonhazardous site.
Results:
This demonstration was evaluated using the following four types of performance testing: 1) computer model validation;
2) soil movement testing, including heat grid tests; 3) barrier diffusion and leaking tank tests; and 4) barrier integrity
testing. The barrier diffusion and leaking tank tests were used to demonstrate containment by the frozen barrier wall by
releasing Rhodamine-WT from a tank inside the containment structure and measuring its potential diffusion across the
barrier wall.
- Tests showed that Rhodamine was found only inside the barrier region, confirming barrier integrity.
- Tests showed that Rhodamine migrated approximately two feet in unfrozen soils, while essentially no Rhodamine was
found below open-ended well casings within the freeze barrier.
216
-------
Case Study Abstract
Frozen Soil Barrier Technology at the SEG Facilities, Oak Ridge,
Tennessee in Cooperation with U.S. Department of Energy
Oak Ridge Operations (Continued)
Cost Factors:
- Total capital costs for the SEG demonstration were $481,427.
- Maintenance costs for the demonstration were estimated as $40,000 per year ($3322 per month).
- Nd additional details provided on components of capital or maintenance costs.
- Unit costs identified for this technology ranged from $4 to $14 per cubic foot of iced formed, and are compared with
unit costs for grout systems ranging from $1 to $37 per cubic foot.
- Report authors indicated that a more realistic cost (i.e., for an actual remedial activity) for this type of technology
would be $332,754, assuming that extra sensors and test support were not needed, if equipment were leased instead of
purchased, and barrier thickness was decreased (which would mean less drilling, energy consumption, etc.).
Description:
Frozen soil barrier technology was demonstrated under the sponsorship of the U.S. DOE In Situ Remediation
Integrated Demonstration Program at a nonhazardous site on SEG property at the Gallaher Road Facility in Oak Ridge
Tennessee. Frozen soil barrier technology has been used for a number of years in large-scale civil engineering projects
to seal tunnels, mine shafts, and other subsurface structures against flooding, and to stabilize soils during excavation.
Advantages of frozen soil barrier technology include: 1) it can provide complete containment; 2) it uses benign material
(water/ice) as a containment medium; 3) frozen barriers can be removed by thawing; and 4) frozen barriers can be
repaired in situ (by injecting water into the leaking area).
At the SEG demonstration, a "V"-shaped containment structure was constructed 56 feet long by 56 feet wide by 28 feet
deep. Refrigerant piping was used to create an area of frozen soil ranging from 5 to 15 feet thick. Several types of
performance testing were performed, including barrier diffusion and leaking tank tests, based on use of a surrogate
solution containing 200 ppm of Rhodamine-WT. The barrier diffusion and leaking tank tests showed that Rhodamine
was found only inside the barrier region, confirming barrier integrity, and that Rhodamine migrated approximately two
feet in unfrozen soils, while essentially no Rhodamine was found below open-ended well casings within the freeze
barrier.
Determining the suitability of this technology for applications for arid/sandy environments will require development of
methods for homogeneously adding and retaining moisture in the soils. In addition, technology applications in fine-
grained soils around structures may be limited because of soil movement.
217
-------
SECTION 1
SUMMARY
Technology Description
The technology of using refrigeration to freeze soils has been employed in large-scale engineering projects for a number of years.
This technology bonds soils to give load-bearing strength during construction; to seal tunnels, mine shafts, and other subsurface
structures against flooding from groundwater; and to stabilize soils during excavation. Examples of modern applications include
several large subway, highway, and water supply tunnels.
Ground freezing to form subsurface frozen soil barriers is an innovative technology designed to contain hazardous and radioactive
contaminants in soils and groundwater. Frozen soil barriers that provide complete containment ("V" configuration) are formed by
drilling and installing refrigerant piping (on 8-ft centers) hon'zontally at approximately 45° angles for sides and vertically for ends and
then recirculating an environmentally safe refrigerant solution through the piping to freeze the soil porewater. Freeze plants are used
to keep the containment structure at subfreezing temperatures. Advantages for this technology include the following:
• It can provide complete containment.
• It uses benign material (water/ice) as a containment medium.
• Frozen barriers can be removed (by thawing).
• Frozen barriers can be repaired in situ (by injecting water into the leakage area).
Technology Status ^^«^^»««M—--——«—-——•————-———^•••—••^—••—-•^
A full-scale "V-shaped"
containment structure (56
ft long x 56 ft wide x 28 ft
deep) was demonstrated
from May 12 to October
10,1994, at a nonhaz-
ardous site on SEG prop-
erty at the Gallaher Road
Facility in Oak Ridge,
Tennessee. The project
was sponsored under the
U.S. Department of
Energy In-Situ
Remediation Integrated
Demonstration Program by
the Office of Technology
Development (EM-50).
Surrogate solutions (200
ppm Rhodamine-WT) were
used to test the integrity
characteristics of the
barrier.
Refrigeration plant
' Stand pipes
• Underground Storage Tank
• Cryogenic Manifolds
Remote-actuated
valve
Backfill Area (sand trench)
Page 1
U.S. Department of Energy
218
-------
SUMMARY
continued
Key Results
• Time-constrained laboratory studies showed that effective frozen soil barriers (hydraulic permeabilities < 4x10E-10 cm/sec) can be
formed in saturated soils for chromate (4000 mg/kg) and trichloroethylene (TCE) (6000 mg/kg). Tests with cesium-137 showed no
detectable diffusion through the barrier although sorption on the soil grains may have been responsible for the immobility.
• Soil movement can be predicted accurately for fine-grained soils based on past civil engineering practices.
• Computer modeling of heat transfer characteristics and soil temperature for fine-grained soils was validated.
• Costs associated with engineering, construction, operation, and maintenance of frozen soil barriers in fine-grained soils using full-
scale equipment were established (for a nonhazardous site).
• Electropotential studies utilizing frozen soil's low electrical conductivity properties showed low ionic transport across the frozen soil
barrier, indicating that the barrier is an effective deterrent to ionic transport.
• Excavation of the nonfrozen soil within the contained area and ground penetrating radar studies showed (1) the inner area to be in
the predicted formation ("V shape) and (2) the frozen wall thicknesses to be approximately 15 ft in the sand trench area and 5 to
9 ft in the clay-dominated areas.
• Diffusion studies (with Rhodamine-WT as the tracer) conducted by Los Alamos National Laboratory (LANL) confirmed barrier
integrity.
• An in-place temperature-monitoring system provided soil temperature information confirming barrier formation.
• The Frozen Soil Barrier process is based upon U.S. Patent No. 4,860,544, issued to RKK Ltd. for CRYOCELL ground freezing
technology.
Contacts
Technical
Rick Swatzell, Principal Investigator, Martin Marietta Energy Systems, Inc. (MMES), 615-435-3126
Ray Peters, Scientific Ecology Group (SEG), 615-376-8194
Management
Jef Walker, DOE EM-50, DOE Plumes Focus Area Program Manager, 303-903-7966
Page 2
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U.S. Department of Energy
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SECTION 2
TECHNOLOGY DESCRIPTION
1.0 Purpose
The purpose of this project was to provide the U.S. Department of Energy with an innovative technique for controlling waste migra-
tion in soils by demonstrating the use of frozen soil barriers. This project had the following goals and objectives:
• Demonstrate in situ isolation of a simulated waste from the environment.
• Provide complete containment of the simulated waste.
• Construct a subsurface barrier without adding injectants or any barrier materials.
• Demonstrate long-term control of in situ waste.
• Conduct barrier monitoring and integrity testing.
2.0 Description of the Demonstration Facility
The dimensions of the frozen soil barrier region were 56 ft by 56 ft (outside) and 33 ft by 33 ft (inside) once the ice barrier was fully
formed.
Inner freezing Grid
• Freeze pipes were installed in dou-
ble-rowed configuration for overlap.
• Pipes were installed at a 45' angle
to establish a bottom to the contain-
ment structure.
• Pipes were set on 8-ft centers with
the two rows set at 4-ft centerlines,
and the ice wall was allowed to
grow together forming the barrier.
• An array of heating pipes was
installed inside the freeze grid to
allow some oil heave control.
• The piping material was 4-in.
schedule 10 carbon steel for both
freeze and heat grids.
* Monitoring was accomplished
through additional pipes inserted
around the site. Resistance tem-
perature detectors (RTDs) were
placed inside these pipes at 5-ft
intervals.
~7
c
c
c
4' C
a
— e
c
c
3 '
C
C
c
3
C
l^
3
3 C
> C
3 C
3 C
C
3
c
3
' 16' »
3 ---•.- <
> C> c
3 «
<
Heating Grid -^
A
3
C
3
C
3
C
3
re
3}
c
3
C
3
3
3
3
5
3— •
3
3
6'
Outer Freezing Grid ^
Page3
U.S. Department of Energy
220
-------
TECHNOLOGY DESCRIPTION
continued
A sand trench was built to _ Ground Level
cross the area that would
be consumed by the frozen
barrier to insure that the
tracer material would have
an adequate flow path. The
native soil was determined
to be clayey with low per-
meability. The trench was 8
ft below the surface and 6
ft thick with native soil
packed over to backfill to
grade.
A carbon steel tank measuring 52.5 in. high by 65 in. diameter was buried in the center of the sand trench. This tank was used as
the distribution point for releasing the tracer during the barrier integrity testing phase of the project.
The site was covered with a plastic liner to prevent rain infiltration, insulate against surface warming, and allow the freeze front to
reach the surface.
Ground freezing apparatus used for the demonstration project consisted of surface equipment (refrigeration unit, heat source, and
piping) and subsurface equipment (freeze pipes, heat pipes, and monitoring wells).
Major surface components and/or characteristics of the freeze barrier demonstration are as follows:
Sand Trench
M
i
I
|
Frozen Zone
• Refrigeration Capacity
• Refrigerant
• Compressor
• Condenser
• Evaporators
• Evaporator Temperature
• Coolant (calcium chloride brine)
Two 40-Ton Units
R-22
Rotary Screw
Evaporative
Shell and Tube
Approximately 35°C
1.28 specific gravity
•^ *v>*» ^ „ , j£ j'« ~i
> > , *< * ComponehtlV -
Compressor Motor
Condenser Fan Motor
Condenser Water Pump
Motor
Lube Oil Pump
Brine Pump
Ancillary Pumps and
Controls
Total
i i
Horsepower
250
20
2
3
40
5
320
The following chart shows power requirements for the two 40-ton refrigeration units used on site:
- Page 4 ———^^^^«_-=
221
U.S. Department of Energy
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SECTION 3
PERFORMANCE
Testing the frozen barrier consisted of looking at the physical aspects of soil freezing, the containment characteristics of the barrier,
and the physical characteristics of the barrier once it was formed.
This evaluation was accomplished with four kinds of testing:
• computer model validation;
* soil movement testing, including heat grid tests;
* barrier diffusion and leaking tank tests; and
• barrier integrity testing.
Results obtained are discussed in the next section.
Computer Model Validation '
Purpose
To compare predicted energy consumption and frozen barrier temperatures during formation and operation of the frozen barrier, to
confirm the accuracy of ground freezing calculations, and to improve the parameters used in such calculations.
Test Equipment
Computer model, monitoring system (for both soil and brine temperature), flowmeters, and electrical meter.
Test Results
• The field data and calculated temperature
data are in close agreement.
• Actual power consumption (420,000 kW-
hours) showed good agreement with pre-
dicted values (380,000 kW-hours).
• To the extent that convective heat transfer
coefficients can be quantified and the ther-
mal properties of the soil can be character-
ized, this analysis provides an effective
analytical tool for predicting how long it
takes to develop the freeze barrier to the
design thickness and the shape of the
freeze wall. Finite element analysis can be
a useful tool for developing freeze wall
designs and selecting refrigeration equip-
ment
Temperature vs. Time - Comparison of Field Data
and Modelling Results
*
1
I
70
60
50
40
30
20
10
0
0 200 400 600 800 1000 1200 1400 1600
Time (hours)
Model —Field
Field data ftom monitoring well TP1-4A
Pages
U.S. Department of Energy
222
-------
PERFORMANCE
continued
Soil Movement Test
Purpose
This test measured soil movement and stresses on a tank buried in the center of the barrier test facility. Soil movement was
expected because of the wet and fine-grained nature of the soil at the site, which is classified as "frost-susceptible" by the U.S. Army
Corps of Engineers' Cold Regions Research and Engineering Laboratory (CRREL) according to their grain size criterion for silty and
clayey soils. This test also determined the effect on soil movement when the heating grid was used.
Test Equipment
Ten benchmarks, transit, strain gages, flowmeters, and temperature sensors were installed within the demonstration site.
Benchmarks were constructed by drilling 3-ft-deep holes by hand with a post hole digger. Holes were backfilled with concrete, and
36-in. sections of iron rebar were inserted into the concrete. Approximately 10 to 12 in. of rebar was exposed at the marker sur-
face. In addition, two benchmarks for the tank (the 2-in. and 4-in. risers) were measured.
Test Results
• The heat grid was effective in
slowing the rate of increase in
tank movement.
• The maximum stress calculated
as part of the analysis was 4,000
psi. The allowable stress for car-
bon steel is 12,000 psi.
• Soil movement of 1.65ft
observed during first 70 days was
in good agreement with predicted
values (between 1.20 and 2.24
ft).
• Maximum lift of any monuments
was 2.25 ft.
• The heat grid was effective in
controlling inward growth of the
barrier (ice).
Soil Movement Data BM-1-0 through BM-10-0
-30
-20
-10 0 10 20
Distance From Centerline (feet)
10Days 50Days "100Days •ISODays]
40
Barrier Diffusion and Leaking Tank Test
Purpose and Plan
The barrier diffusion and leaking tank testing were to provide quantitative measures of the effectiveness of the frozen soil barrier in
preventing the passage of hazardous and radioactive wastes in the form of water-borne chemicals. Design of the tracer experiments
had three phases: (1) hydraulic conductivity testing of the permeable sand trench crossing a segment of the then-unformed cryo-
genic barrier wall using fluorescein, (2) demonstration of containment by the cryogenic barrier wall following closure by releasing
Rhodamine-WT from the tank inside the containment structure, and (3) comparison of tracer movement in the frozen native soil with
that in unfrozen native soil at the demonstration site.
Test Equipment
Diffusion monitoring wells, tracers (200 ppm solutions of fluorescein, Rhodamine-WT), and fluorescence spectrometer.
Page 6
223
U.S. Department of Energy
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PERFORMANCE
continued
Test Results
• Substantial hydraulic conductivity was shown through the sand trench by the appearance of fluorescein in recovery well WO-A
(outside the planned barrier) in less than 4 hours (Figure 5).
• Rhodamine was found only inside the barrier region, showing barrier integrity (see Figure 6).
• Phase 3 tests showed that Rhodamine migrated approximately 2 feet in unfrozen soils, while essentially no Rhodamine tracer
was found below open-ended well casings within the freeze barrier.
Barrier Integrity Testing b*MMiM^^MMM««MaMM«M«^^
Purpose and Plan
Barrier integrity testing consisted of (1) measuring the electropotential of the soil to indicate reduced ionic transport properties
(reduced electrical conductivity of frozen soil) through the frozen soil region and (2) performing ground penetrating radar studies of
the barrier wall after the barrier-contained interior (unfrozen section) was excavated.
Test Equipment
Passive and active electrodes (for electropotential measurements), computer data collection and analysis system, and ground pene-
trating radar instrumentation.
Test Results
• Bectropotential measurements showed low ionic transport across the frozen soil barrier walls.
• Excavation of the contained area within the frozen barrier confirmed the desired "V" configuration, and subsequent ground pene-
trating radar measurements showed the barrier wall to be approximately 12-15 ft thick within the sand trench area and approxi-
mately 5-9 ft thick within clay-dominated areas.
Uniform Electric Flux Field in the Southeast Corner of the
"ICE BARRIER"
Potential Color Coding
Page?
U.S. Department of Energy
224
-------
SECTION 4
Technology Applicability
Radioactive, heavy metal, and organic contaminants can be contained by this technology.
Laboratory studies have shown that frozen soil barriers with low hydraulic permeabilities (< 4x10E_10 cm/sec) can be formed in
saturated soil conditions.
Formation of frozen soil barriers in saturated, fine-grained soils has been demonstrated in the field.
The formation of frozen soil barriers in arid conditions will require a suitable method of homogeneously adding moisture to the
soils to achieve saturated conditions before the technology can be assessed for that application.
Soil movement should be a factor to consider for applications in fine-grained soils around structures (buildings, submerged tanks
and piping, etc.).
Barriers should be such that they will not degrade upon contact with contaminant solutions.
Formation of frozen soil barriers in areas where plumes of low-freezing-point contaminants (TCE, etc.) exist may require more
expensive cryogenics (e.g., liquid nitrogen).
Competing Technologies
• Frozen soil barrier technology is competitive with other subsurface flow-control technologies such as liners, slurry walls, sheet pil
ing, and grouting.
• Comparison with other technologies is difficult because of the unique aspects of ground freezing technology, including complete
containment and removability. In addition, ground freezing incurs additional energy, operation, and maintenance costs over time
that other containment technologies do not. However, it appears that this technology can be effectively applied in fine-grained, sat-
urated soils for "complete" containment applications of relatively moderate durations where future remedial action of the contami-
nant source and subsequent barrier removal are desired.
Technology Maturity Immmmmmmmmmmmmmmmmm^^ <
• The technology of using refrigeration for the freezing of soils has been employed in large scale engineering projects for a number
of years. It bonds soils to give load-bearing strength during construction; to seal tunnels, mine shafts, and other subsurface struc-
tures against flooding from groundwater; and to stabilize soils during excavation. Examples of modern applications include sever-
al large subway, highway, and water supply tunnels.
• Frozen soil barriers have not been demonstrated at an actual contaminated site.
Paged
225
U.S. Department of Energy
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SECTION 5
COST
The total capital cost for the SEG Demonstration was $481,427. It can be assumed that if demonstration costs such as those for the
extra sensors and test support were deducted and if costs were reduced by purchasing (vs renting) equipment and by decreasing
barrier thickness (which would mean less drilling, energy consumption, etc.), the real cost would be about $332,754. Engineering,
health and safety, and permitting costs are not reflected in that figure. The maintenance cost for this frozen barrier was estimated to
be$3322/month.
The contact area of the envelope created by the frozen barrier was 2223 ft2. The volume of frozen soil composing the frozen barrier
was 35,694 ft3, and the volume of soil contained by the frozen barrier was 8175 ft3.
The cost shown below are for volume of ice formed. The results of the cost analysis are:
SEG
Demon
($481,427)
Actual
Site
($332,754)
Cost
Attributes
Frozen
Barrier
Volume
Frozen
Barrier
Volume
First-Year
Total
14/ft3
10/ft3
15-Year
Average
Maintenance
Cost
1.2/ft3
1.12/ft3
15-Year
Maintenance
Cost Per
Month
0.09/ft3
0.09/ft3
SEG
Demon
Actual
Site
5.5
Months
13/ft3
9/ft3
Yearl
Total
14/ft3
10/ft3
Years
2-5
4/ft3
4/ft3
Years
6-10
6/ft3
6/ft3
Years
11-15
6/ft3
6/ft3
In contrast with these calculations, if one of literally several hundred types of grout were used in place of a frozen barrier, costs
could range from $1/ft3 to $37/ft3. These types of grout use a multiplicity of ingredients/recipes including Portland cement, bentonite,
waxes, chemical components, and proprietary "magic dust." However, grout does not have the advantages of moderate-duration
"complete" containment and removal capabilities as frozen soil barriers do.
Page 9
U.S. Department of Energy
226
-------
SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations ^^
• No permit was required for this demonstration because the demonstration was performed on a nonhazardous site and a benign '
barrier material (water) was used. Regulatory participation was encouraged. If moisture additions were required (e.g., for arid site
applications) in soils of high hydraulic conductivity (sandy soils), concerns about contaminant migration downward would have to
be addressed. In addition, refrigerants of low toxicity (in cases of refrigerant pipe leakage) must be used and complete in situ bar-
rier integrity must be confirmed by subsurface barrier verification techniques before regulatory acceptance can be gained.
Safety, Risks, Benefits, and Community Reaction •
Worker Safety
• Health and safety issues for installation (drilling, etc.) and operation are essentially equivalent to those for conventional environ-
mental monitoring applications (monitoring well drilling, etc.).
Community Safety
• Frozen soil barrier systems do not produce contaminant releases because benign materials (water, nontoxic refrigerants, etc.) are
used.
• No unusual or significant safety concerns are raised by the transport of equipment, samples, waste, or other materials associated
with frozen soil barrier systems.
Environmental Impacts
• Drilling for refrigerant piping installation is required.
• Surface piping manifolds are required to supply refrigerant to the system.
• Compressor (refrigerant plant) noise is minimal.
Page 10
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U.S. Department of Energy
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SECTION 7
LESSONS LEARNED
Design Issues
E
In situ temperature sensors installed within the refrigerant piping provided valuable information on barrier formation and refrigera-
tion equipment operation.
Typical refrigeration equipment (piping, refrigeration plants, etc.) can be used to form in situ frozen soil barriers. Single-row piping
may be adequate to form barriers of sufficient thicknesses to contain contaminants. In addition, a single refrigeration plant (40 ton)
can be employed to maintain barrier integrity (soil freezing conditions) after initial heat removal is acquired.
Computer modeling for soil heat transfer characteristics can be used to predict barrier formation.
Methods need to be designed for "injecting" moisture and lower-freezing-point refrigerants into barrier areas where leaks are
detected (or where refrigerants have leaked because of pipe breakage).
Sol movement can be predicted using experiences of past civil engineering practices and should be a consideration when
designing a system for applications involving structures.
Careful installation of the refrigerant piping is necessary to ensure "complete" barrier formation.
For applications in humid and high ambient temperature regions, proper ground insulation and near-surface refrigerant piping
may be required to ensure that surface to 1-2-ft depths are adequately frozen (if desired).
In situ sensors (electrical conductivity, etc.) should be preinstalled in the soil to monitor barrier formation.
Geophysical measurements of the barrier area should be performed before freezing to establish soil characteristics and hetero-
geneities.
Technology Limitations/Needs for Future Development i
i
* Remote sites will require electrical power and utility installation.
• Technology applications for arid/sandy environments are undetermined until suitable methods are developed for homogeneously
adding and retaining moisture in the soils.
• Technology applications in fine-grained soils around structures (submerged tanks, etc.) may be limited because of soil movement.
* Longer-duration applications at actual contaminated sites need to be studied to assess diffusion characteristics, costs, etc.
* In situ subsurface barrier verification technologies (enhanced ground penetrating radar, seismic, acoustics, electropotential, trac-
ers, etc.) need to be developed that are capable of detecting barrier traverses as well as barrier infrastructure properties (voids,
etc.).
• Additional laboratory diffusion studies may be required for various contaminants of differing concentrations. Contaminant solu-
tions' effects on barrier degradation should be studied.
Page 11
U.S. Department of Energy
228
-------
APPENDIX A
DEMONSTRATION SITE CHARACTERISTIC^,
Site History/Background [•••••••••••^^ «*• *.. ===_*
The site used for the demonstration project is located at the SEG Gallaher Road Facility in Oak Ridge, Tennessee.
The demonstration site is approximately 200 ft west of the access road entrance to the plateau area above Gallaher Road. The
plateau area is a large, flat, unpaved area approximately the size of a football field. The plateau was constructed by "cutting and fill-
ing" with soil removed from a hillside (about 30 ft high) located along the southeastern side of the site about 25 years ago. The
plateau was graded to its current contour and has not been used for any other known purpose.
Description of Soil Testing and Results E
Soil testing was performed at the site on September 8 and September 9,1993. The test report includes soil moisture contents,
sieve analyses (hydrometer), and unit weight determination. A total of six test borings were drilled with augers to depths ranging
from 25 to 46.3 ft.
Moisture content samples were taken in 5-ft intervals during penetration testing. The moist unit weight of the sample was obtained
with a Shelby tube. The unit weight of the undrained soil at boring B-5 was 108.8 Ib/ft3.
Subsurface soils encountered at the site at the time of our exploration generally consisted of 13 to 22 ft of fill soils that overlie resid-
ual soils. The fill soils were composed of stiff to hard red-brown silty clay, with varying amounts of chert fragments. The residual
soils were composed of stiff to soft red-brown to brown silty clay and clayey silt, with varying amounts of chert fragments.
The soils were very fine as determined by hydrometer testing. The consistency of residual soil generally graded from stiff to soft
with depth. The residual soils at the site are typical of the soils encountered overlying the dolomite of the Knox Group of the lower
Ordovician System in the Oak Ridge area.
Moisture contents obtained from the soil samples show the following:
"• *,' •»
^^JJpriog, * -'
> „*• Nunther'^ J
1
2
4
5
vf 5Nantb%it.0f L '
I ^Samples :*.,
3
9
6
8
^ *_V •>">.
* '•*» "High*"^ ^*v"
J -5 ;..(%)- \
37.2
43.0
37.8
40.0
: '-fa* ;~
,- ^%) •"-
32.3
12.1
20.8
16.8
~~ " s - '
• ^vecage ' ;
-------
APPENDIX B
REFERENCES
1. Scientific Ecology Group, Final Report: Demonstration of Ground Freezing Technology at SEG Facilities in Oak Ridge, Tn., pre-
pared for Martin Marietta Energy Systems, Inc., Hazardous Waste Remedial Actions Program, February 1995.
2. Dale Morgan and David Lesmuth, Ground Penetrating Radar Investigation of a Frozen Earth Barrier, Earth Resources
Laboratory, Massachusetts Institute of Technology, report to Martin Marietta Energy Systems, Inc., Hazardous Waste Remedial
Actions Program, December 1994.
3. ISOTRON Corporation, Electro-Potential Tomography of Frozen Soil Barrier, report to Martin Marietta Energy Systems, Inc.,
Hazardous Waste Remedial Actions Program, November 1994.
4. J. G Dash, Haying Fu, and Roger Leger, Bench Scale Testing of Hanford and Oak Ridge Soils: Formation and Diffusion Testing
of Cryogenic Barriers, Final Report of the Low Temperature Physics Laboratory of the University of Washington, Department of
Physics, University of Washington, report to Martin Marietta Energy Systems, Inc., Hazardous Waste Remedial Actions Program,
December 1994.
5. Law Engineering, Ground Freezing Project Facility, Gallaher Ferry Road Site, Law Report 382 93242 01, September 1993.
Page B1
U.S. Department of Energy
230
-------
This report was prepared by:
Hazardous Waste Remedial Actions
HAZWRAP
P.O J3ox 2003
Oak Ridge, Tennessee 37831-7606
Contact: Randall Snipes/Scott Colbum
(423)435-31287(423)435-3470
in conjunction with:
Colorado Center Cor Environmental Management
CCEM
999 18th Street, Suite 2750
Denver, Colorado 80202
Contact: Dawn Kaback
(303)297-0180 Ext. Ill
231
-------
-------
ResonantSonic Drilling
233
-------
Case Study Abstract
ResonantSonic Drilling
Site Name:
U.S. Department of Energy (DOE),
1. Hanford Site
2. Sandia National Laboratory
Location:
1. Richland, Washington
2. Albuquerque, New Mexico
Contaminants:
Not used at contaminated sites
Period of Operation:
1992-1994 (see results)
Cleanup Type:
Field demonstration
Technical Information/Vendor:
Information not provided
SIC Code:
9711 (National Security)
Others - information not provided
Technology:
ResonantSonic Drilling
- Used to access the subsurface for
installation of monitoring and/or
remediation wells and for collection of
subsurface materials
- Uses a combination of mechanically
generated vibrations and limited rotary
power to penetrate soil
- Drill head consists of two counter rotating,
out-of-balance rollers that cause the drill
pipe to vibrate
- Transmits 50,000 to 280,000 Ibs of force to
the drill pipe; drills hole diameters up to 16
inches
- Newer designs also include drill head
rotation capability
Cleanup Authority:
Not used at contaminated sites
Points of Contact:
Information not provided
Waste Source:
Not used at contaminated sites
Purpose/Significance of
Application:
ResonantSonic drilling, an
alternative to traditional drilling
technologies, was shown in some
applications to be less costly and
produce less drilling wastes than
cable tool or mud rotary
technologies.
Type/Quantity of Media Treated:
Soil and Sediment
- At Hanford, most drilling occurred in two fades: a coarse-grained sand and
granule-to-boulder gravel; and a fine-to-coarse-grained sand and silt
- At Sandia, sediments are extremely heterogeneous, complexly-interlayered
units consisting of sands, gravels, and cobbly units, with discontinuous low-
permeability layers present
Regulatory Requirements/Cleanup Goals:
- Not used at contaminated sites
- Docs not require addition of fluids to a well, which in some states is restricted
Results:
- Initial Hanford demonstration averaged 23.9 ft drilled per day (8.9 ft/day, including downtime)
- Well depths ranged from 30 to 227 ft
- Provided intact h'thologjc samples
- Second Hanford demonstration included boreholes drilled at 45° angles, with wells up to 172 ft long
- Sandia demonstration included 3 different drill rigs, with 5-10% less down time than at Hanford
234
-------
Case Study Abstract
ResonantSonic Drilling (Continued)
Cost Factors:
- Capital and operating costs for the demonstrations are not provided in the report
- A comparison of cost ($/ft) for ResonantSonic, cable-tool, and mud-rotary drilling is provided based on a hypothetical
scenario, for regular and difficult drilling
- ResonantSonic drilling ranged from $208-270/ft, cable-tool from $600-758/ft, and mud-rotary from $221-951/ft,
depending on type of site and type of drilling
Description:
ResonantSonic drilling has been demonstrated at the U.S. DOE Hanford and Sandia sites as an alternative to cable tool
and rotary-mud drilling. This technology is used for installation of monitoring and/or remediation wells, and for
collection of subsurface materials for environmental restoration applications. Advantages of ResonantSonic drilling
include: lower cost per foot for drilling, can provide relatively undisturbed continuous core samples; uses no drilling
fluids and minimizes waste generation; and can be used to drill slant (angle) holes.
ResonantSonic drilling uses a combination of mechanically generated vibrations and limited rotary power to penetrate
soil. The drill head consists of two counter-rotating, out-of-balance rollers that cause the drill pipe to vibrate, and
transmit force to the drill pipe. From 1991 to 1994, this technology was used on uncontaminated soil in two
demonstrations at Hanford and three at Sandia, with an additional demonstration planned at Hanford. These
demonstrations included drilling hole diameters up to 16 inches.
Results from these demonstrations were used to improve system design and operation. For example, the initial Hanford
demonstration had high percentages of downtime, while later demonstrations at Sandia resulted in much less downtime.
These demonstrations included wells drilled up to 227 ft deep, and several wells drilled at 15-45° angles. Further, this
technology shows significant waste minimization compared to mud rotary. However, heating core materials remains an
issue where no fluid is used to cool the formation and under difficult drilling conditions. ResonantSonic generated core
temperatures from 70°F to 140°F under difficult drilling conditions at Hanford. In addition, few drilling companies
currently provide ResonantSonic drilling services. This should be considered in selecting this drilling alternative.
235
-------
SECTION 1
SUMMARY
Technology Description 6
ResonantSonic^ drilling has been demonstrated and deployed as an innovative tool to access the subsurface for installation of
monitoring and/or remediation wells and for collection of subsurface materials for environmental restoration applications. The tech-
nology has been developed by industry with assistance from the U.S. Department of Energy (DOE) Office of Technology
Development to ensure it meets the needs of the environmental restoration market.
The ResonantSonic drilling technology:
• can provide excellent quality, relatively undisturbed, continuous core samples that can be used for contaminated site charac-
terization and for subsurface engineering design;
• uses no drilling fluids and minimizes generation of waste associated with the drilling operations (no cuttings);
• provides an alternative drilling method that at some locations is more cost effective than the baseline technology (e.g., at
Hanford it can augment or replace cable tool drilling);
• can be used to drill slant holes;
• can be safer because worker exposure is minimized, because drilling is faster and waste generated is minimized; and
• can be used for retrieving core materials from the subsurface (i.e., sample collection), for installation of monitoring wells, and
for providing subsurface access for collection of ground water samples.
Sonic Head
Drill Pipe
llgh Speed
Counter Balances
Produce Resonant
Energy Waves
Resonant Waves
Minimize Borehole
Wall Friction on
Drill Pipe
• The ResonantSonic drilling system consists of two components: the drill head and the resonator (i.e., the drill pipe or rod).
• Three different mechanisms allow the bit to penetrate the formation: displacement, shearing, and fracturing. At any particular site,
the mechanism is dependent upon the soil medium being drilled.
• ResonantSonic drilling has been used at many geologically different sites ranging from unconsolidated gravel-rich material to
sandstone/shale sequences to clay-rich glacial till sites.
• Continuous cores have been obtained at depths as great as 550 feet.
• Drilling rates range up to 260 feet per day.
• Costs range from $70 to $300 per foot depending upon the drilling system used, the drilling approach, the site geology, etc.
i "Registered Service Mark of Water Development Corporation"
Page 1 ——
U.S. Department of Energy
236
-------
SUMMARY
continued
Technology Status i — • *
• The original patent was developed by Albert Bodine in the early 1960s; the technology was used for pile driving and mineral
exploration, especially in Canada. Several U.S. companies have purchased the Canadian equipment and licensed any existing
patents to pursue a new market for this drilling technology.
• Water Development Corporation of California teamed with the Department of Energy via a Cooperative Research and
Development Agreement (CRADA) to advance the application of this technology to the environmental business. The joint indus-
try-government partnership mission was to develop and demonstrate improvements to the ResonantSonic technology so that it
could be applied cost effectively to environmental restoration sites with special focus on difficult drilling sites such as the DOE
Hanford Site.
• Field demonstrations of the ResonantSonic drilling technology were conducted at the DOE Hanford Site and at Sandia National
Laboratory from 1991 through 1994. Refinements to the drilling system concentrated on improving the reliability of the equipment,
developing new bit designs, pursuing automated tool handling and decontamination systems, and demonstrating angle drilling
capabilities.
• Additional demonstrations have been conducted at the DOE Pantex Site in Amarillo, Texas and at a number of DOD military
bases. Further, the technology has been implemented at the DOE Rocky Flats Site, at the Idaho National Engineering Laboratory,
and at a number of private locations in California.
• Key results of the public-private partnership technology development program include the following:
• In the initial demonstration at Hanford, penetration rates were twice that of the baseline technology; later results showed
improvements.as high as three to four times that of the baseline.
• Equipment refinements included a new sonic head design, new drill pipe designs, an automated pipe handling system, and
an extended-length split-tube sampler.
• A method to maintain core temperatures, below 90 degrees Fahrenheit, to assure quality core recovery for VOC analysis was
developed and tested.
• A new rig that has multiple drilling technology capabilities (sonic, air rotary casing hammer, cable tool, percussion, and rotary)
was designed and manufactured. The advantages of such a system include the ability to mix and match drilling technologies
to the required objectives at each specific drilling location.
• Angle-drilled wells have been installed at both Sandia National Laboratory and Hanford.
• The technology is commercially available. The number of companies that can provide such services is quite limited, however.
Contacts
Technical
Don Moak/Greg McLellan (pi), Westinghouse Hanford Company, (509) 373-7219/373-7539
Jack Wise, Sandia National Laboratories, (505) 844-6359
Jeffrey Barrow, Water Development Corporation, (916) 662-2829
Management
David Biancosino, DOE EM50 Program Manager, (301) 903-7961
Jim Wright, DOE Plumes Focus Area Manager, (803) 725-5608
Licensing Information
Jeffrey Barrow, Water Development Corporation, (916) 662-2829
Page 2
237
U.S. Department of Energy
-------
SECTION 2
TECHNOLOGY DESCRIPTION
Overall Drilling Rig Schematic
ResonantSonicsm Drilling Method
High Speed
Counter Balances
Produce Resonant
Energy Waves
I
Resonant Waves
Minimize Borehole
Wall Friction on
Drill Pipe
• The ResonanlSonic drilling rig uses a combination of mechanically generated vibrations and limited rotary power to penetrate the soil
• The oscillator or drill head consists of two counter rotating, out-of-balance rollers that cause the drill pipe to vibrate. The rollers
are synchronized with each other to ensure that the vertical force component is transmitted downward along the drill pipe or core
barrel.
Uppor «od Lowor
AUChamtwi
Conlor Column
Ak Spring
Piston
OieflMor
Homing
Column le
Drill StMl
Adaptor Rang*
Rol.llonil
Dilv*
Motor
Page3
U.S. Department of Energy
238
-------
TECHNOLOGY DESCRIPTION
continued
1 The vibrations are isolated from the rig structure by the use of an air spring.
1 Resonance occurs when the frequency of the vibrations is equal to the natural frequency of the drill pipe. In resonance, forces
generated by the oscillator head can build up in the pipe from 50,000 to 280,000 pounds. The resonance and weight of the drill
pipe along with the downward thrust of the drill head permit penetration of the formation.
Resonant Sonic
Drill Head
Anttnode Location:
Point of Maximum Strain
(Compraulon or Expansion)
in Molecular Structure
Superimposed
Induced Preeeure Wave
and Reflected Preeeure Wave
Expanding and Compreaaing Pipe
Steel DrBI Pipe
Node Location:
Point of Minimum Strain
In Molecular Structure
Standing Wave:
Fundamental
One-Half Wavelength
Condition
Amplitude of
Wave Cycle
MR Bit
Wave Variation With Time
• The newly designed ResonantSonic drill head also has rotation capability up to 8,500 foot pounds of torque to assist with penetra-
tion of the formation.
• Vibrations generated in the drill string range from 0 to greater than 150 Hertz and create up to 200,000 pounds of force. The drill
pipe is advanced into the ground by weight applied hydraulically at the surface.
System Configuration and Operation ==
' There are two primary methods for retrieving core samples from the subsurface: the wireline method and the dual-rod method.
Each method, of course, has advantages and disadvantages. The selection of a specific method must be tailored to the site-spe-
cific needs and conditions. The advantages and disadvantages of the two methods with a comparison to rotasonic drilling are dis-
cussed in Reference 5.
• The wireline method uses an open-face core bit threaded to the bottom of the drill pipe. An inner core barrel rests on the
shoulder of the bit and is kept in place during drilling by a downhole latch assembly or heavy weight. After drilling has pro-
ceeded far enough that the barrel is filled, the wireline retrieval system is attached to the core barrel so that it can be
removed without pulling the drill pipe out of the hole.
• The dual-rod system is similar to the wireline method, but the core barrel is attached to a small diameter steel inner rod,
which then must be removed during core retrieval. This assures quality seating of the core barrel. Both drill rods can be res-
onated simultaneously or independently, depending upon formation conditions. Little if any rotation of the drill rods is used
Page 4 — _=^^=^=========^=====^
239
U.S. Department of Energy
-------
continued
with this system. Neither the wireline nor the dual rod method requires addition of fluids to the subsurface. They both can be
used with the ResonantSonic system.
• Borehole Integrity is maintained by the drill pipe that remains in the ground as the core barrel is retrieved and as the hole is
advanced. Typical drill pipe diameter is 4.5 inches outer diameter (OD). Larger-size drill pipe ranging from 6 5/8 to 16 inch diam-
eter can be used when telescoping pipe is required to seal a perched zone or confined aquifer or to make larger diameter moni-
toring or remediation wells.
1 To install monitoring wells, the drill pipe acts as a temporary casing, inside of which the well materials can be placed for installa-
tion. It is quite easy to retrieve the temporary casing because it can be sonically vibrated to assist removal.
• Specifications of the six different drilling rigs used for the Hanford and Sandia demonstrations are shown below.
Sonic drilling rig
Resonant frequency
Rig Power
Maximum force
generated by the drill
head
Maximum force
transmitted due to
hydraulic thrust alone
Hole diiameler that
can be drilled
15-year-old
rig used at
Hanford
0 to 150
Hertz
250 Hp
50,000 Ibs.
10,000 Ibs.
up to 7 in.
"Barber"
rig used at
Sandia
Oto15
0 Hertz
250 Hp
50,000 Ibs.
15,000 libs
up to 6 5/8 in.
"Dresser"
rig used at
Sandia
0 to 150
Hertz
250 Hp
50,000 Ibs.
15,000 Ibs.
up to 6 5/8 in.
"Angle" rig
used at
Sandia
Oto15
0 Hertz
250 Hp
50,000 Ibs.
15,000 Ibs.
up to 6 5/8 in.
"RSD300"
rig used at
Hanford
0 to 150
Hertz
300 Hp
100,000 Ibs.
30,000 Ibs.
up to 10 3/4 in.
"RSD750"
planned at
Hanford
Oto15
0 Hertz
1200 Hp
200,000 Ibs.
90,000 Ibs.
up to 16 in.
Operational Requirements t
1 ResonantSonic drilling requires one driller and one helper as a minimum for operation. Drilling at hazardous waste sites, of
course, requires additional personnel. At a DOE hazardous waste site the field team could include a field team leader, a geolo-
gist, a site safety officer, a sampling scientist, a health physics technician, and two sampling technicians. The large number of
personnel required significantly affects the cost of the drilling operation and maximizes the cost differential between different
drilling technologies, because one technology is faster than the other.
• The ResonanlSonic drill required about 2.5 hours of preventive maintenance per week during the first demonstration and less dur-
ing subsequent demonstrations.
• The Los Alamos National Laboratory (LANL) cost estimate uses a figure of $20,000 per year cost for preventive mainte-
nance.
• Stress on the drill pipe produced during resonance causes internal damages. Magnetic scanning of the drill pipe (magna-
fluxing) can be performed routinely to reveal microfractures. However, microfractures are not readily identified in all cases
because the initial failure points occur within the body of the pipe.
PageS
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SECTION 3
PERFORMANCE
Demonstration Overview
First demonstration with Harrison Western, Inc., 1991-1992
• The first demonstration of ResonantSonic drilling technology, which took place in 1991 at Hanford, was conducted jointly by DOE
EM40 and EM50 to determine whether sonic drilling is a cost-effective alternative to the currently used cable-tool system for
drilling and sampling at hazardous and radioactive waste sites at Hanford. Other requirements for the system include protection
of human health and the environment and compliance with state and federal regulations.
CRADA demonstrations with Water Development Corporation, 1993-1994
• Objectives of the 1993 demonstrations included the following:
• Demonstrate the efficiency and reliability of the sonic drill head in penetrating variable geologic conditions.
• Demonstrate angle drilling capabilities and determine areas for improvements.
• Develop and install an instrumentation system to electronically record the resonant drilling process.
• Correlate recorded drilling measurements with geology.
• Test and evaluate sampling equipment and sample handling methods for both vertical and angle drilling.
• Demonstrate that ResonantSonic drilling can meet safety standards and compliance with state regulations for well completions.
• Demonstrate the ability to maintain contamination control and minimize generated waste.
• Demonstrate ability to obtain high quality samples (including maintenance of an acceptable bit face temperature) and drill to
required depths at required diameters.
• Evaluate cost effectiveness of ResonantSonic versus cable tool drilling.
• Determine the radial distance from the borehole of vibrations generated during drilling.
• Demonstrate, evaluate, and select a preferred sonic drill rod.
Drilling Performance C
First Hanford Demonstration, 1991-1992
• The first demonstration at Hanford utilized a fifteen-year-old rig (Hawker-Siddely drill owned by Harrison Western Drilling, Inc.).
This demonstration was plagued with high percentages of downtime due mostly to head and drill string failures related to the age
of the equipment. This first demonstration laid the groundwork for future development work by demonstrating the technology's
potential while demonstrating the need for more development.
• The ResonantSonic drill averaged 23.9 feet per day as compared with the average rate of 12.6 feet per day for cable tool (down-
time excluded for both technologies). Including downtime, sonic averaged 8.9 feet per day and cable tool averaged 8.1 feet per
day on a comparison of ten sonic drilled boreholes and 11 cable tool drilled boreholes. Average cable tool drilling rates at Hanford
in 1991 ranged from 6.4 to 9.5 feet per day.
• Eight ground water monitoring wells, one ground water monitoring/extraction well, and two vadose zone characterization bore-
holes were completed during the demonstration. The borings ranged in depth from 30 to 227 feet and were located in several
areas at the Hanford Site (100-D, 300,3000,200 East, and 200 West).
• The ResonantSonic drilling system provided intact lithologic samples that are not usually retrieved with the cable tool system.
Sample quality for the sonic boreholes was at least equal to that of cable tool in sand and silt formations and was greater in hard
formations unless large cobbles were encountered.
• The ResonantSonic drilling system protected human health and the environment by minimizing waste generation and easily con-
taining cuttings.
• The ResonantSonic drilling method offers several advantages for well completion: temporary casing can be rotated and placed in
resonance to prevent bridging of the completion material (this results in faster installation of the annular seal); rig hydraulics can
be used to unscrew and handle the temporary casing; the same crew can be used for well installation (no additional crew mobi-
lization is required).
Page 6
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PERFORMANCE
continued
Dr. Bill Schutte of the
DOE Office of
Technology
Development watches
the Hanford
ResonantSonic
drilling demonstration
with Mr. Greg
McLellan, principal
investigator,
Westinghouse
Hanford Company.
Hanford CRADA Demonstrations, 1993-1994
• During the first phase of this demonstration program, five boreholes were drilled, four of which were at 45 degree angles. The two
deepest wells reached total lengths of 164 and 172 feet. Drilling rates averaged six feet per hour.
• Sampling equipment and methods investigated included core tray, split tube samplers, and core barrel liners.
• Concerns about sampling of core for analysis of VOCs due to heating of the core were examined and a new methodology was
developed to minimize temperature elevation in the core. During the first demonstration at Sandia and Hanford, core samples
An example of unsonsolidated
core removed using the
ResonantSonic system.
were heated to temperatures unacceptable for chemical sampling.
• An extended-length split-tube sampler was designed to be driven ahead of the drill string and filled to only 75% of its length
to obtain samples for chemical analysis.
• Other improvements include reductions in drilling frequencies and rotation rate as a result of real-time temperature monitor-
ing, lining of the samplers with low thermal conductivity materials (Lexan), and pre-chilling the samplers with dry ice in special
coolers.
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PERFORMANCE
continued
1 The second phase included installation of a 45-degree-angle vapor-extraction borehole to a measured depth of 168 feet (118 feet
vertical depth) with 3-inch stainless steel casing at a hazardous waste site under a parking lot in the 200 West Area.
• New developments in the drilling system included the use of Lexan liners to collect superior quality core, core temperatures
held to under 90 degrees Fahrenheit, and the use of a robotic arm to handle the drill pipe.
• Downtime was less than five percent.
n ,^.
t \
• Later phases of the CRADA demonstrations included drilling with larger-diameter drill pipe (up to 20 inches) and installation of
deep wells (310 feet) with 4-inch stainless steel pipe.
• Drill pipe analysis showed that eddy currents could detect abnormal electric or magnetic features in the threaded fastener region,
where pipe failure occurs most often. Failure analysis of the pipe itself demonstrated a difference between pipe that was threaded
directly and in pipe that utilized threaded tool pieces.
DOE Sand/a National Laboratory Demonstrations
• In 1993 three different ResonantSonic rigs were demonstrated at Sandia. All three were rigs newer than that used at the 1991-
1992 Hanford demonstration.
• Technological advances in both the drill head and drill string resulted in much less downtime (averaged 5-10%) during the
Sandia demonstrations.
• Two 4-inch PVC slant wells (15 degrees from horizontal) were installed beneath the Chemical Waste Landfill to a depth of 150
feet.
• During the drilling operations, dynamic drilling measurements were made to obtain information on pipe integrity. A new instru-
mented subassembly was designed and manufactured to be used for this demonstration. This was the first step.toward
development of diagnostic capabilities to enhance drilling performance through optimized control and improved hardware
design.
• The boreholes did not deviate off linearity by more than one-half degree over the full length of the wells.
Page 8
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U.S. Department of Energy
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PERFORMANCE
continued
DOE Pantex Demonstration 1994
• Four continuous core boreholes were completed to average depths of 290 feet, where a continuous perched water interval over-
lying the Ogalalla Aquifer exists.
• Depth-discrete ground water sampling using the HydroPunch and geophysical logging were combined with the ResonantSonic
drilling method to maximize the amount of information obtained from each of the boreholes.
• The amount of waste generated was 2% of that normally obtained using the baseline Pantex technology.
Page 9
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SECTION 4
TECHNOLOGY APPLICABILITY AND ALTERNATIVE TECHNOLOGIES
Marketplace Opportunities
1 The optimum application of ResonantSonic drilling technology will be at sites where:
1) high-quality core materials are required; the ResonantSonic drilling system provides intact core samples that demonstrate
detailed lithological parameters such as thin layers (such as clays and chemical precipitates) and fragile structures (deposi-
tional and fossiliferous features) that are normally not observed in samples collected by other drilling methods;
2) where there is a requirement to minimize the.amount of hazardous waste generated; Land Disposal Restrictions (LDR) now
require containment, storage, and ultimate treatment of investigative-derived wastes such as drill cuttings and drilling fluids;
3) when regulators prefer the use of a drilling technology that does not add fluids to the subsurface; at many sites there may be
concerns about the migration of contaminants being exacerbated by the addition of drilling fluids; and
4) lithology is not conducive to conventional technology (e.g., karst).
Alternative Technologies • , =2
Rotasohic
• This technology, most closely related to the resonant sonic method, is a modification of the original Albert Bodine patent and is
presently commercially available from a few companies in the United States.
• Rotasonic drilling uses a core barrel attached to a drill rod as an inner casing. The core barrel is advanced sonically until it has
been filled. The core barrel is then overwashed with a fluidized outer rotational casing, which provides hole stability while the
inner drill string is pulled to retrieve the core. Disadvantages of this method include the requirement for addition of water to the
subsurface for advancing casing and the time required to drill two holes, the cored section and the washover. One advantage is
more rapid drilling penetration rates due to the fluidized condition of the borehole.
• The major disadvantage to this system, only at certain sites, is the requirement for the addition of water to the subsurface.
• Advantages that may offset this disadvantage include greatly increased penetration rates, much less stress on the tools and the
overall system, and reduction of heat generated.
• Drilling rates with the rotasonic technology can be as high as 160 feet per day but of course are highly dependent upon the type
of lithology being drilled.
• Depth is currently limited to 300 to 400 feet and the size of casings to be advanced is limited to eight inches.
• Rotasonic technology has been demonstrated for environmental applications at the DOE Savannah River Site and Oak Ridge
National Laboratory and will soon be implemented at the Femald Site in Ohio. It has been utilized extensively at a number of
other sites including Wright-Patterson Air Force Base.
Competitive Technologies
• Competitive drilling technologies, including the baseline typically used within certain areas of the United States, consist of the fol-
lowing: cable tool, hollow-stem auger, mud rotary, air rotary, dual-wall percussion hammer, dual-tube reverse circulation, and air
rotary casing hammer.
• Some of these technologies require the addition of fluids to the subsurface, and many generate significant quantities of hazardous
waste when used at environmental restoration sites.
• A more complete discussion of drilling technologies can be found in reference 5. Costs for each of the technologies are very site
dependent.
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SECTION 5
COST
introduction
Information in this section was prepared from data provided by the VOCs in Arid Soils Integrated Demonstration at the DOE Hanford
Site and the Mixed Waste Landfill Integrated Demonstration at the DOE Sandia National Laboratory to the Los Alamos National
Laboratory (LANL), tasked to perform technology cost analyses as an independent team for the DOE Office of Environmental
Management Office of Technology Development (EM-50).
•The LANL cost analysis was not meant to involve comprehensive cost estimation for borehole drilling and/or well completion.
Thus, the final cost-per-foot numbers would not be expected to match actual contract rates.
•The data provided to Los Alamos for the Hanford demonstrations relied solely on work performed in 1991-1992. This cost informa-
tion was based on using 15-year-old drilling equipment and did not incorporate any of the advancements developed as a result of
the technology development CRADA program in place over the last few years. Cost information from the later demonstrations will
be available in the near future. Preliminary information suggests that costs have been significantly reduced, by as much as a fac-
tor of three.
•The testing at Sandia involved drilling of smaller diameter holes. Costs at Hanford are higher for this and a number of other rea-
sons. Costs cannot be correlated from site to site.
COSt Comparisons U^HBMMMMMMHHMMHIHHMBMMMMH^^
Two conventional technologies will be used as baselines for comparison to ResonantSonic Drilling. At Hanford, cable-tool drilling is
considered to be the baseline for this cost analysis. At Sandia mud rotary drilling was considered the baseline for the cost analysis.
A side-by-side comparison of three technologies was performed based on the following assumptions:
•The scenario assumed a hypothetical 150-foot well to be drilled in three environments: 1) a clean environmental site, containing
no hazardous or radioactive material, 2) a hazardous environmental site (EPA listed), and 3) a mixed-waste site, containing both
hazardous and radioactive waste.
•Two separate soil conditions were considered: 1) regular drilling, which refers to the somewhat easier drilling of unconsolidated
formations, and 2) difficult drilling, which refers to cobble/boulder/consolidated and clay layers where greater resistance to drill
advance Is encountered.
•Capital costs were included as rig rental to produce an overall drilling rate on a cost-per-foot basis. The table below presents a
dollars/foot comparison of the three methods of drilling.
Capital and Operating COStS tmmammmmmmmmmmmmmmmmmmm^mmmHm^^
Capital costs for the three systems are all within the same order of magnitude. The cost of a ResonantSonic drill rig is only an esti-
mate but the capital cost is a small contributor, approximately 5% of the cost per foot for monitoring wells.
Capital Costs
Drill Rig
Equipment Cost
ResonantSonic Drilling
$400,000
Cable-Tool Drilling
$200,000
Mud-Rotary Drilling
$ 450,000
The operational and maintenance costs for the three systems are comparable on a per-hour basis. The variance begins to be evi-
dent at a price-per-foot cost because of the speed at which ResonantSonic and mud-rotary drilling can proceed. ResonantSonic
drilling is slower than mud-rotary but does not generate significant quantities of waste to be disposed of when working in a contami-
nated environment.
Page 11
U.S. Department of Energy
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COST
continued
Cost comparison Somc/Cable-tool/Mud-rotary
Regular Drilling Difficult Drilling
o
,o
CO
O
1000
800
600
400
200
C/3
J3
174
J*
a>
I OT
147
424
88
133
61
163
174
436
-a
x
88
381
61
190
174
458
88
807
%\v
u
c/5
c
ju
U
3 S5
•s
X
174
424
88
188
61
182
174
483
88
436
61
209
174
584
88
°s
Cost Results
•The demonstrations at Sandia show that the technology may begin to compete with mud-rotary drilling at clean sites.
•At contaminated sites, ResonantSonic drilling is clearly more cost effective.
•1994 drilling at Hanford showed lower costs.
• 3 holes were drilled to an average depth of 309 feet, 11-inch diameter.
• 2 of these holes were completed as 4-inch wells and 1 was completed as a 3-inch piezometer.
• Drilling costs were $194 per foot; costs including a field sampling team were $253 per foot.
•Recent drilling at Hanford to install shallow 3-inch piezometers has been accomplished for as little as $30 per foot.
•Additional cost information using the new drilling equipment is needed to validate the cost effectiveness of the ResonantSonic
technology. Prudence should be exercised in using the 1991 -1992 cost data.
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SECTION 6
REGULATORY/POLICY ISSUES
Regulatory Considerations
•The ResonanlSonfc drilling technology requires all of the normal permits associated with other drilling technologies. No special
permits should be required.
•The Hanford demonstration did not require NEPA review because the testing was part of the site characterization activities for the
Expedited Response Action (ERA), meeting the requirements for a categorical exclusion. Drilling at many of the DOE federal
sites, such as the Savannah River Site, is considered under NEPA to be a categorical exclusion.
•Wells must be constructed according to state standards but should not present any difficulties over other drilling methods.
•Normal drilling activities require that investigative-derived wastes (drilling fluids, cuttings, and equipment decontamination fluids) be
handled according to RCRA.
•OSHA requirements must be reviewed because ResonantSonic drilling, like all drilling methods, produces noise levels that are con-
sidered dangerous to workers not wearing proper protection. New style heads have significantly reduced noice levels.
Regulatory Advantages
•The ResonantSonic drilling technology has a regulatory advantage over the mud rotary technique, and to a lesser extent cable-tool
technique, in that it does not require any addition of fluids to the well. Some states do not allow the addition of material into the
ground at contaminated sites. ResonantSonic drilling permits installation of wells under these restrictions.
Safety, Risks, Benefits, and Community Reaction C
Worker Safety
• Health and Safety issues for the installation and operation of ResonantSonic drilling are essentially equivalent to those for conven-
tional drilling technologies. Worker exposure to hazardous and radioactive materials will be less because drilling fluids are not
used and cuttings are not generated.
• Level D personnel protection was used during the operation of the ResonantSonic drilling system.
Community Safety
• ResonanlSonfe drilling does not produce routine release of contaminants.
• No unusual or significant safety concerns are associated with transport of equipment samples, waste, or other materials associat-
ed with ResonantSonic drilling.
Environmental Impacts
• ResonantSonic drilling systems require relatively little space similar to other drilling systems.
• Visual impacts are minor, but operation of the drill rig create moderate noise in the immediate vicinity.
Socioeconomic impacts and Community Perception
• ResonantSonic drilling has a minimal economic or labor force impact.
• The general publfc has limited familiarity with ResonantSonic drilling.
Page 13
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SECTION 7
LESSONS LEARNED
Implementation Considerations
1 When considering the selection of ResonantSonic at a particular site, the ResonantSonic drilling technology must be compared
with other drilling technologies and evaluated on the basis of specific site needs and conditions.
• At Hanford it has been compared with the baseline cable tool technology, and at Sandia it has been compared with a base-
line mud rotary system (see cost section).
1 Waste minimization is a significant feature of sonic drilling.
• At Hanford sites characterized as not difficult, ResonantSonic drilling generated about the same amount of waste as the
cable tool system, whereas under difficult drilling conditions sonic generated approximately one-fourth the amount of waste.
• Comparison of ResonantSonic drilling to mud rotary shows significant minimization of waste using the sonic method.
1 Heating of core materials to be sampled for volatile chemical contaminants remains an issue for drilling technologies where no
fluid is used to cool the formation, especially under difficult drilling conditions.
• Both ResonantSonic and cable tool have been shown to generate core temperatures from 70 to 140 degrees Fahrenheit
under difficult drilling conditions at Hanford.
• Hollow-stem augering has been demonstrated to increase core temperatures to 107 degrees Fahrenheit, but temperatures
average 76 degrees.
• New techniques to minimize temperature elevations in core materials have been developed, demonstrated, and should be
implemented when collecting core samples for chemical analyses of volatile components (see Section 4, Hanford CRADA).
Technology Limitations/Needs for Future Development
« Richterich (1994) noted that "further study of factors such as lithology, penetration rates, amount of vibration, rotation, etc. should
be studied to improve the quality of the core runs."
• Few drilling companies can provide ResonantSonic drilling services. Thus, the costs of mobilization may preclude the cost effec-
tive use of the technology, especially when only a few boreholes are required to complete a job.
• Further demonstration and implementation of the Sandia National Laboratory dynamics monitoring system should be completed
so that imminent drill pipe failures can be predicted in real-time and coordinated with a system shutdown. In addition, improved
understanding of the dynamics of ResonantSonic drilling will ultimately lead to further improvements in tool-joint design.
• Needs include design and manufacture of different-sized drilling rigs so that the right system can be used for the job, optimizing
costs incurred.
• Work is under way to combine the ResonantSonic technology with push technology such as the cone penetrometer to assist with
penetration of thin, hard layers. Development of this new system will create a new niche that will enhance the drilling toolbox.
Technology Selection Considerations
1 Development, manufacture, and implementation of drilling systems with capabilities of multiple technologies will likely provide the
lowest cost/highest quality methodology under difficult drilling conditions.
• Using the WDC new drilling rig, wells at Hanford were installed using the ResonantSonic Casing Drive Method in the unsatu-
rated zone and the ResonantSonic dry core method conbined with cable-tool hole-cleanout technology below the water table.
• Many sites will benefit from the application of push technology for small-diameter and shallower holes. However, a relatively
large percentage of sites will require innovative drilling technology such as sonic.
Specific job requirements and site conditions will dictate the application of the best drilling technology or combination of technolo-
gies at a particular site. Innovative technologies, such as ResonantSonic drilling, should be considered within the toolbox of avail-
able technologies.
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U.S. Department of Energy
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APPENDIX A
DEMONSTRATION SITE CHARACTERISTICS
1 Field demonstrations of the sonic drilling technology described in this report were conducted at both the DOE Hanford Site and
Sandia National Laboratory.
Geographic/Geologic
Setting of Washington
Subprovince / \ '
lue Mountains \ / o
Subprovince )/ gC
o so 100 OREGON
-44'
PageAl
U.S. Department of Energy
250
-------
APPENDIX A
continued
Most of the drilling for the ResonantSonic demonstrations occurred within the Hanford Formation, which contains two facies:
(1) a coarse-grained sand and granule-to-boulder gravel from which matrix is commonly lacking, and
(2) fine- to-coarse-grained sand and silt that commonly display normally graded rhythmites a few centimeters to several decime-
ters thick. In general, the coarse facies is composed of approximately 50 percent sand and gravel, 45 percent cobble, and
five percent boulder, and ranges in thickness from 20 feet to greater than 200 feet. The underlying fine facies consists of 5 to
60 feet of silts and fine sands, which in turn are underlain by Plio-Pleistocene Palouse soils, which consist of eolian silts and
clay overlying a caliche layer of cemented silt, sand, and gravel.
Geographic Setting of
Hanford Site
Saddle Mtns.
Rattlesnake Hills
0 M'LES 5
0 5
KILOMETERS
PageA2
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U.S. Department of Energy
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APPENDIX A
continued
Generalized Stratigraphy of
the Suprabasalt Sediments
at the Hanford Site
Pleistocene
Pliocene
Miocene
Holocene Surficial
Deposits
;e" Soil
Pre-Missoula Gravels
Unit
Pliocene-Pleistocene
Boundary
Paleosols
Page A3
U.S. Department of Energy
252
-------
APPENDIX A
continued
• Below the Palouse soils is about 20 feet of fluvial sands
and muds underlain by relatively well compacted flu-
vial gravels, all of the Ringold Formation.
1 Most of the demonstration work was conducted in the
200 Areas of Hanford where the depth to the water
table is approximately 200 feet.
> The DOE Hanford Site is located in south central
Washington State. «The Sandia National Laboratory, at
Kirtland Air Force Base in Albuquerque, New Mexico, is
located near the east-central edge of the Albuquerque
Basin, one of a series of north-south trending basins that
make up the Rio Grande rift zone. The basin edges are
bounded by uplifted fault blocks. The Albuquerque Basin
is presently filled with up to 12,000 feet of Miocene and
Pliocene sediments that were eroded from the surround-
ing highlands. This sequence of sediments, called the
Santa Fe Group, consists of basin-fill alluvial fan materi-
als, with channel deposits, debris flows, floodplain
deposits, and eolian deposits. The Santa Fe Group sedi-
ments are overlain in places by Pliocene Ortiz gravels and
Rio Grande River fluvial deposits, interbedded with
Tertiary and Quaternary basalts and pyroclastics.
•The sediments are extremely heterogeneous, complexly
interlayered units consisting of sands, gravels, and cobbly
units. Discontinuous low-permeability layers are present
as clay-rich or caliche-cemented zones.
•The water table underlying the site is approximately 500 feet below the surface.
•Wells have been drilled at the site using mud rotary, augers, and air rotary casing hammer
techniques.
Uicalinn MapufCWI.
Water-Supply Wells al KAFB
Page A4
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U.S. Department of Energy
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APPENDIX A
continued
ISO 300 FT
LEGEND
• MW-l MONITORING WELL
TA III FENCE
ise^co
-woo FEET-
Gcncralired Geology and CWL Map Showing Location of Geologic Cross
Sections
Page AS
U.S. Department of Energy
254
-------
APPENDIX B
REFERENCES
1. Volk, B. W., 1992, Results of Testing the Sonic Drilling System at the Hanford Site (September 1991 to May 1992), WHC-SD-
EN-TRP-002.
2. Volk, B.W., D.J. Moak, J.C. Barrow, K.M. Thompson, G.W. McLellan, R.E. Lerch, 1993, ResonantSonic Drilling: History,
Progress and Advances in Environmental Restoration Programs, WHC-SA-1949-FP.
3. Richterich, L.R., 1994, Phase / Resonant Sonic CRADA Report, WHC-SD-EN-TRP-007.
4. Masten, Dave and Steven Booth, 1995, Cost-Effectivenss Study of Sonic Drilling, Los Alamos National Laboratory Report,
preprint.
5. Barrow, Jeffrey, 1994, The ResonantSonic Drilling Method, Ground Water Monitoring and Remediation, Spring 1994, V.XIV, No.
2., p. 153-160.
6. Wise, Jack, 1994, Arid Sonic Drilling, Sandia National Laboratory TIP AL2-3-10-05.
7. Volk, B.W., G.W.McLellan, and B.R. Cassem, 1993, Sonic Drilling System Technology Demonstration Conceptual Test Plan
1993, Westinghouse Hanford Company.
8. Barrow, Jeffrey, 1995, Water Development Corporation, personal communication.
9. McLellan, Greg, 1995, Westinghouse Hanford Company, personal communication.
10. Wise, Jack, 1995, Sandia National Laboratories, personal communication.
11. Phelan, Jim, 1995, Sandia National Laboratories, personal communication.
12. Booth, Steven, 1995, Los Alamos National Laboratory, personal communication.
Page B1
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U.S. Department of Energy
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This report was prepared by:
Colorado Center
for
Environmental Management
999 18th Street, Suite 2750
Denver, Colorado 80202
Contact: DawnKaback
(303)297-0180Ext. Ill
in conjunction with:
Hazardous Waste Remedial
Actions Program
Martin Marietta Energy Systems
P.O. Box 2003
Oak Ridge, Tennessee 37831-7606
Randall Snipes/Scott Colburn
(615)435-31287(615)435-3470
Assistance was provided by the
Westinghouse Hanford Company
and
Water Development Corporation
256
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