EPA542-R-98-015
September 1998
Remediation Case Studies:
Innovative Groundwater
Treatment Technologies
Volume 11
CD
^
Federal
Remediation
Technologies
Roundtable
Prepared by the
Member Agencies of the
Federal Remediation Technologies Roundtable
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Remediation Case Studies:
Innovative Ground water
Treatment Technologies
Volume 11
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
September 1998
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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. Environmental Protection
Agency under EPA Contract No. 68-W5-0055.
ll
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FOREWORD
This report is a collection of twelve case studies of innovative groundwater treatment technology projects
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 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 1-6, and Abstracts, Volumes 1 and 2, were published previously, and
contain 54 case studies. Remediation Case Studies, Volumes 7-13, and Abstracts, Volume 3, were
published in September 1998. Volumes 7-13 cover a wide variety of technologies, including innovative
groundwater treatment technologies (Volume 11). The 12 innovative groundwater treatment technology
case studies in this report include completed full-scale remediations and large-scale field demonstrations.
In the future, the set will grow as agencies prepare additional case studies.
1995 Series
Volume 1: Bioremediation, EPA-542-R-95-002; March 1995; PB95-182911
Volume 2: Groundwater Treatment, EPA-542-R-95-003; March 1995; PB95-182929
Volume 3: Soil Vapor Extraction, EPA-542-R-95-004; March 1995; PB95-182937
Volume 4: Thermal Desorption, Soil Washing, and In Situ Vitrification, EPA-542-R-95-005;
March 1995; PB95-182945
1997 Series
Volume 5: Bioremediation and Vitrification, EPA-542-R-97-008; July 1997; PB97-177554
Volume 6: Soil Vapor Extraction and Other In Situ Technologies, EPA-542-R-97-009;
My 1997; PB97-177562
1998 Series
Volume 7: Ex Situ Soil Treatment Technologies (Bioremediation, Solvent Extraction,
Thermal Desorption), EPA-542-R-98-011; September 1998
Volume 8: In Situ Soil Treatment Technologies (Soil Vapor Extraction, Thermal Processes),
EPA-542-R-98-012; September 1998
ill
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1998 Series (continued)
Volume 9: Groundwater Pump and Treat (Chlorinated Solvents), EPA-542-R-98-013;
September 1998
Volume 10: Groundwater Pump and Treat (Nonchlorinated Contaminants), EPA-542-R-98-014;
September 1998
Volume 11: Innovative Groundwater Treatment Technologies, EPA-542-R-98-015;
September 1998
Volume 12: On-Site Incineration, EPA-542-R-98-016; September 1998
Volume 13: Debris and Surface Cleaning Technologies, and Other Miscellaneous
Technologies, EPA-542-R-98-017; September 1998
Abstracts
Volume 1: EPA-542-R-95-001; March 1995; PB95-201711
Volume 2: EPA-542-R-97-010; July 1997; PB97-177570
Volume 3: EPA-542-R-98-010; September 1998
Accessing Case Studies
The case studies and case study abstracts are available on the Internet through the Federal Remediation
Technologies Roundtable web site at: http://www.frtr.gov. The Roundtable web site provides links to
individual agency web sites, and includes a search function. The search function allows users to complete
a key word (pick list) search of all the case studies on the web site, and includes pick lists for media treated,
contaminant types, and primary and supplemental technology types. The search function provides users
with basic information about the case studies, and allows them to view or download abstracts and case
studies that meet then- requirements.
Users are encouraged to download abstracts and case studies from the Roundtable web site. Some of the
case studies are also available on individual agency web sites, such as for the Department of Energy.
In addition, a limited number of hard copies are available free of charge by 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
Phone: (513)489-8190 or
(800) 490-9198
Fax: (513)489-8695
IV
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TABLE OF CONTENTS
Section
INTRODUCTION [[[ l
INNOVATIVE GROUNDWATER TREATMENT TECHNOLOGIES CASE STUDIES ........... 9
Enhanced Bioremediation of Contaminated Groundwater -
Balfbur Road Site, Brentwood, CA; Fourth Plain Service Station Site,
Vancouver, WA; Steve's Standard and Golden Belt 66 Site, Great Bend, KS .............. 11
Coagulation/Flocculation/Dissolved Air Flotation and Oleofiltration™ at
the Coastal Systems Station, AOC 1, Panama City, Florida ......... .................. 33
Pump and Treat and Permeable Reactive Barrier to Treat Contaminated
Groundwater at the Former Intersil, Inc. Site, Sunnyvale, California .................... 55
Pump and Treat and In Situ Bioremediation of Contaminated Groundwater
at the French Ltd. Superfund Site, Crosby, Texas ............................. ..... 73
Pump and Treat and Air Sparging of Contaminated Groundwater at the
Gold Coast Superfund Site, Miami, Florida ....................................... 91
Pump and Treat and In Situ Bioremediation of Contaminated Groundwater
at the Libby Groundwater Superfund Site, Libby, Montana .......................... 109
Permeable Reactive Barrier to Treat Contaminated Groundwater at the Moffett
Federal Airfield, Mountain View, California ..................................... I31
Dual Auger Rotary Steam Stripping at Pinellas Northeast Site, Largo, Florida ............ 147
In Situ Anaerobic Bioremediation at Pinellas Northeast Site, Largo, Florida .............. 183
PerVap™ Membrane Separation Groundwater Treatment at Pinellas
Northeast Site, Largo, Florida ........................................ ........ 221
Pump and Treat, In Situ Bioremediation, and In Situ Air Sparging of
Contaminated Groundwater at Site A, Long Island, New York ........................ 247
In Situ Permeable Reactive Barrier for Treatment of Contaminated
Groundwater at the U.S. Coast Guard Support Center, Elizabeth City,
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This Page Intentionally Left Blank
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 (Roundtable) are working jointly to publish case studies of full-scale remediation and
demonstration projects. Previously, the Roundtable published a six-volume series of case study reports.
At this time, the Roundtable is publishing seven additional volumes of case study reports, primarily focused
on soil and groundwater cleanup.
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 agreed to by the agencies. These procedures
are summarized in the Guide to Documenting and Managing Cost and Performance Information for
Remediation Projects (EPA 542-B-98-007; October 1998). (The October 1998 guide supersedes the
original Guide to Documenting Cost and Performance for Remediation Projects, published in March 1995.)
The case studies present available cost and performance information for full-scale remediation efforts and
several large-scale demonstration projects. They 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 on technology cost and
performance may be limited.
The case studies in this volume describe twelve groundwater remediation applications that used innovative
treatment technologies. Three of the applications used permeable reactive barriers; four used in situ
bioremediation (some in conjunction with pump and treat); one used air sparging alone; one used a
combination of in situ bioremediation, air sparging, and pump and treat; one used a combination air and
stream stripping process; one used a membrane filtration process; and one used a chemical reaction and
dissolved air flotation process. Seven of these applications were conducted at full scale, and the
remaining five at a field demonstration scale. Contaminants treated included chlorinated solvents,
petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and metals. Some of these
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applications are ongoing, and the case studies are interim reports about these applications.
Table 1 provides a summary including information on technology used, contaminants and media treated,
and project duration for the 12 innovative groundwater treatment technology applications in this volume.
This table also provides highlights about each application. Table 2 summarizes cost data, including
information on quantity of media treated and quantity of contaminant removed. In addition, Table 2 shows
a calculated unit cost for some projects, and identifies key factors potentially affecting project cost. (The
column showing the calculated unit costs for treatment provides a dollar value per unit of groundwater
treated or contaminant removed.) Cost data are shown as reported in the case studies and have not been
adjusted for inflation to a common year basis. The costs should be assumed to be dollars for the time
period that the project was in progress (shown on Table 1 as project duration).
While a summary of project costs is useful, it may be difficult to compare costs for different projects
because of unique site-specific factors. However, by including a recommended reporting format, the
Roundtable is working to standardize the reporting of costs to make data comparable across projects. In
addition, the Roundtable is working to capture information in case study reports that identify and describe
the primary factors that affect cost and performance of a given technology. Key factors that potentially
affect project costs for incineration projects include economies of scale, concentration levels in
contaminated media, required cleanup levels, completion schedules, matrix characteristics such as soil
classification, clay content and/or particle size distribution, hydraulic conductivity, pH, depth and thickness
of zone of interest, total organic carbon, oil and grease or total petroleum hydrocarbons, presence of
NAPLs, and other site conditions.
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Table 1. Summary of Remediation Case Studies: Innovative Groundwater Treatment Technologies
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Balfour Road Site, CA; Fourth Plain Service
Station Site, WA; Steve's Standard and Golden
Belt 66 Site, KS
(Enhanced Bioremediation of Groundwater)
Coastal Systems Station, AOC 1 , FL
(Chemical Reaction and Flocculation, and
Dissolved Air Flotation) -
Former Intersil, Inc. Site, CA
(Pump and Treat with Air Stripping; Permeable
Reactive Barrier)
French Ltd. Superfund Site, TX
(Pump and Treat with Activated Sludge for
Extracted Groundwater, In Situ Bioremediation)
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(126,400 gallons)
Groundwater: P&T
(38 million gallons)
PRB (2 million
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Status: Ongoing
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Status:
PRB Ongoing
Report Covers:
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(2/95-11/97)
Status: Ongoing
Report Covers:
1/92 - 12/95
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Evaluate the cost and performance of
ORCR to remediate groundwater at
three sites
Demonstrate the effectiveness of
CRF/DAF and Oleofiltration™ in
treating TPH and metals in wastewater
from a full-scale bioslurper system
Used P&T for eight years; replaced
this technology with PRB; PRB used
for three years
Regulatory requirements for this site
based on use of modeling results to
show effects of natural attenuation at a
site boundary 10 years after pump and
treat completed
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Table 1. Summary of Remediation Case Studies: Innovative Groundwater Treatment
Technologies (continued)
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Gold Coast Superfund Site, FL
(Pump and Treat with Air Sparging)
Libby Groundwater Superfund Site, MT
(Pump and Treat; Li Situ Bioremediation)
Moffett Federal Airfield, CA
(Permeable Reactive Barrier)
Pinellas Northeast Site, FL
(In Situ Air and Steam Stripping -Dual Auger
Rotary Steam Stripping)
Pinellas Northeast Site, FL
(In Situ Anaerobic Bioremediation)
Pinellas Northeast Site, FL
(Membrane Filtration - PerVap)
Principal CoittstiMlaaHt&*
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Groundwater
(250,000 gallons)
Groundwater
(6,200 gallons)
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7/90 - 3/94:
pump and treat
11/94-2/95:
air sparging
Status: Ongoing
Report Covers:
9/91 - 12/96
Status: Ongoing
Report Covers:
4/96 - 7/97
12/96-4/97
2/7/97-6/30/97
6/14/95 - 3/2/96
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Met goals witiiin four years of
operation; included pump and treat and
air sparging
Combination of pump and treat and in
situ bioremediation at site with
LNAPL, DNAPL, and dissolved-phase
contaminants
Use of PRB technology in a pilot study
for treatment of chlorinated solvents;
included extensive sampling conducted
at locations within the wall
Demonstration of in situ air and steam
stripping technology used to
supplement an ongoing system of pump
and treat with air stripping
Demonstration of in situ anaerobic
bioremediation technology used to
supplement an ongoing system of pump
and treat with air stripping
Demonstration of the PerVap™
technology for treating VOC-
-------
Table 1. Summary of Remediation Case Studies: Innovative Groundwater Treatment
Technologies (continued)
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Site A (actual name confidential), NY (Pump and
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Air Sparging; Soil Vapor Extraction)
U.S. Coast Guard Support Center, NC
(Permeable Reactive Barrier)
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System included groundwater
extraction, air sparging, and SVE wells
Use of PRB to treat groundwater
contaminated with TCE and hexavalent
chromium; extensive sampling
conducted to evaluate PRB
> Principal contaminants are one or more specific constituents within the groups shown that were identified during site investigations.
-------
Table 2. Remediation Case Studies: Summary of Cost Data
-:; :;^l^m^^iate;CfedmQjD^"V !
Balfour Road Site, CA; Fourth Plain
Service Station Site, WA; Steve's
Standard and Golden Belt 66 Site,
KS
(Enhanced Bioremediation of
Groundwater)
Coastal Systems Station, AOC 1, FL
(Chemical Reaction and Flocculation,
and Dissolved Air Flotation)
Former Intersil, Inc. Site, CA
(Pump and Treat with Air Stripping;
Permeable Reactive Barrier)
French Ltd. Superfund Site, TX
(Pump and Treat with Activated
Sludge for Extracted Groundwater, In
Situ Bioremediation)
Gold Coast Superfund Site, FL
(Pump and Treat with Air Sparging)
Libby Groundwater Superfund Site,
MT
(Pump and Treat; In Situ
Bioremediation)
Moffett Federal Airfield, CA
(Permeable Reactive Barrier)
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; €ost{$)'1
Balfour Road:
$33,500; Fourth
Plain Service
Station: $35,700
Steve's Standard
and Golden Belt
66: $93,400
Monthly lease
and operation
costs:
CRF/DAF:
$7,580
Oleofiltration:
$3,650
Total (P&T):
$1,343,800
Total (PRB)
$762,000
Total:
$33,689,000
C: $15,487,000
O: $18,202,000
Total: $694,325
C: $249,005
O: $445,320
Total: $5,628,600
C: $3,101,000
O: $2,618,600
Total: $405,000
C: $373,000
O: $32,000
<^nantilyTreated
Not provided
126,400 gallons
Total: 38 million
gallons
P&T: 36 million
gallons
PRB: 2 million
gallons
306 million
gallons
80 million gallons
15.1 million
gallons
0.284 million
gallons
; Quaatltfof
! CajjtfcuniBaJrt
: Bemoved
Not provided
Not provided
Total: 140 Ibs
P&T: 124 Ibs
PRB: 16 Ibs
517,000 Ibs
1,961 Ibs
37,570 Ibs
Not provided
C«J«il*t
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Table 2. Remediation Case Studies: Summary of Cost Data (continued)
Sfce&ggne, S&&p-etfBwJ*
Total: $981,251
(for
demonstration)
Total: $397,074
(for
demonstration)
Total: $88,728
(for
demonstration)
Total: $1,941,560
C: $1,503,133
O: $358,427
Total: $585,000
C: $500,000
0: $85,000
{jtwaftfyTrea&il
2,000 yd3 of soil
0.25 million
gallons
6,200 gallons
8.4 million gallons
2.6 million gallons
f Qtfa>tlty
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Innovative Groundwater Treatment Technologies
Case Studies
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This Page Intentionally Left Blank
10
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Enhanced Bioremediation of Contaminated Groundwater - Balfour Road Site,
Brentwood, CA; Fourth Plain Service Station Site, Vancouver, WA; Steve's
Standard and Golden Belt 66 Site, Great Bend, KS
11
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Enhanced Bioremediation of Contaminated Groundwater - Balfour Road Site,
Brentwood, CA; Fourth Plain Service Station Site, Vancouver, WA; Steve's
Standard and Golden Belt 66 Site, Great Bend, KS
Site Name:
Balfour Road Site
Fourth Plain Service Station Site
Steve's Standard and Golden Belt
66 Site
Location:
Brentwood, CA
Vancouver, WA
Great Bend, KS
Contaminants:
Benzene, toluene, ethylbenzene,
and xylenes (BTEX) and total
petroleum hydrocarbons (TPH)
Period of Operation:
Balfour Road: December 1995 to
present (report covers the period
through October 1997)
Fourth Plain: July 1996 to present
(report covers the period through
October 1997)
Steve's Standard: July 1996 to
present (report covers the period
through October 1997)
Cleanup Type:
Full-scale (Balfour Road and
Fourth Plain)
Demonstration (Steve's Standard)
Vendor:
Steve Koenigsberg
Craig Sandefur
Regenesis Bioremediation
Products, Inc.
27130A Paseo Espada, Suite 1407
San Juan Capistrano, CA 92675
(714)443-3136
Construction/Design:
Thomas Morin (Fourth Plain)
Environmental Partners Inc.
10940 NE 33rd Place, Suite 110
Bellevue.WA 98004
(206) 889-4747
Additional contacts in the report
Technology:
Enhanced Bioremediation of
Groundwater using ORC®
- ORC® (oxygen release
compound) is a proprietary
formulation based on magnesium
peroxide and is available from
Regenesis
- ORC® is applied to the
groundwater using different
methods and dosages (dosage
based on several factors including
the estimated mass of contaminant
at the site and the specific
properties of the aquifer)
- Details of the application method
and dosage for each site are
included in the report
Cleanup Authority:
State voluntary cleanup
State Contacts:
Joel Weiss
California Regional Water Quality
Control Board
Central Valley Region
(916) 255-3077 (Balfour Road)
Carol Fleshes
Washington Department of
Ecology
(206) 649-7000 (Fourth Plain)
Emily McGuire
Kansas Department of Health and
Environment
(913) 296-7005 (Steve's Standard)
Waste Source: Various waste
disposal practices, including leaks
at service stations
Type/Quantity of Media Treated:
Groundwater - estimated 20,400 square feet for Fourth Plain; estimates
were not provided for Balfour Road or Steve's Standard
Purpose/Significance of
Application: Evaluate the cost and
performance of ORC® to remediate
groundwater at three petroleum-
contaminated sites
12
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Enhanced Bioremediation of Contaminated Groundwater - Balfour Road Site,
Brentwood, CA; Fourth Plain Service Station Site, Vancouver, WA; Steve's
Standard and Golden Belt 66 Site, Great Bend, KS
Regulatory Requirements/Cleanup Goals:
- Balfour Road - federal MCLs for groundwater.
Fourth Plain - benzene - 0.005 mg/L, total BTEX - 0.095 mg/L and TPH -1.0 mg/L.
- Steve's Standard - no cleanup goals; demonstration project
Results:
- Balfour Road and Fourth Plain sites - the cleanup goals had not been met at either the Balfour Road or Fourth
Plain sites as of October 1997. The geometric mean concentration and mass of benzene, total BTEX, and TPH
had been reduced by approximately 50 percent.
- Steve's Standard - over the first seven months of operation, the concentration and mass of benzene, total
BTEX, and TPH had been reduced; however, over the next nine months, concentrations appeared to stabilize or
rise slightly; a continuing source was identified at the site. '
Cost:
- Total cost - $41,600 for Bafour Road; $37,300 for Fourth Plain; $96,000 for Steve's Standard.
- Treatment cost - $33,500 for Bafour Road; $35,700 for Fourth Plain; $93,400 for Steve's Standard (two service
stations located next to each other).
Description:
Contamination at each site resulted from leaks in underground petroleum storage tanks and supply pipelines at or
near retail dispensing locations. Refined petroleum product was released to the subsurface soil and groundwater
at each site for unknown periods of time, until being detected in the 1990's. The three sites were cleaned up
under their respective state voluntary cleanup programs. Oversight was performed by the respective state agency
without involvement of EPA. Enhanced bioremediation using ORC® was selected by the lead contractors for
each of the sites because it was expected to reduce the mass of contaminants in the aquifer by more than 50
percent in only six months, thereby reducing risk to human health and the environment from exposure to
contaminated groundwater, and because it required a smaller capital investment and lower operating expenses
than alternative technologies such as pump and treat. Regenesis indicated that enhanced bioremediation using
ORC® was not expected to treat the groundwater to the federal maximum contaminant levels (MCL), but that the
treatment would reduce substantially the dissolved-phase mass of contaminants present in the aquifer, as well as
reduce sources characterized as moderate smear zones.
Enhanced bioremediation was performed at the three sites, using application of ORC®. ORC® is a proprietary
formulation based on magnesium peroxide and is available from Regenesis Bioremediation Products, Inc.
According to Regenesis, the quantity of ORC® required for a site is based on several factors including the
estimated mass of contaminant at the site (dissolved-phase concentration) and the specific properties of the
aquifer such as porosity and thickness. Details on the specific applications of this technology at each of the three
sites in included in the report. As of October 1997, the cleanup goals had not been met at either the Balfour
Road or Fourth Plain sites; however the geometric mean concentration and mass of benzene, total BTEX, and
TPH had been reduced by approximately 50 percent in the aquifers in only 6 months for roughly $50,000 per
site. In addition, at the Steve's Standard site, the concentration and mass of benzene, total BTEX, and TPH had
been reduced in portions of the aquifer. The report presents a detailed summary of the progress at each site and
the olans for future activities at the sites.
13
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
SITE INFORMATION
This report summarizes data on the cost and
performance of enhanced bioremediation using
Oxygen Release Compound (ORC®) to treat
groundwater contaminated with gasoline-range
petroleum hydrocarbons at the following three
sites:
• Balfour Road, Brentwood, California
• Fourth Plain Service Station, Vancouver,
Washington
• Steve's Standard and Golden Belt 66, Great
Bend, Kansas
Table 1 summarizes information about the sites,
including location, operations, year
contamination was detected, source of
contamination, and regulatory agency that
oversees the cleanup.
This report describes remedial activities
involving the use of ORC at three sites at which
groundwater is contaminated with gasoline-
range petroleum hydrocarbons. It provides
information about the cost and performance of
ORC®, methods used to apply ORC® to
groundwater, and lessons learned.
Table 1: Summary of Site Information [2,3,4]
I
Site
Balfour Road
Fourth Plain
Steve's
Standard
Location
Brentwood,
California
Vancouver,
Washington
Great Bend,
Kansas
Operations
Supply
Pipeline
Retail
Station
Retail
Stations
Year
Contamination
Detected
1990
1993
1994
', -Isjourceof
Contamination
Pipeline Leak
Pinhoie Leak below
Product Dispenser
Leak in Piping and
Underground
Storage Tanks
/;: 'Regulatory ' -v
Agency ', ..
California Regional
Water Quality Control
Board
Washington Department
of Ecology
Kansas Department of
Health and the
Environment
Background [2,3,4]
History: Contamination at each site resulted
from leaks in underground petroleum storage
tanks and supply pipelines at or near retail
dispensing locations. Refined petroleum
product was released to the subsurface soil and
groundwater at each site for unknown periods of
time, until being detected in the 1990's.
At Balfour Road, pipeline leaks were discovered
in a gasoline supply pipeline in 1990. From
1990 to 1995, groundwater was extracted at the
site through an excavation trench and treated.
Once the majority of the free product was
recovered, the trench system was no longer a
cost effective solution. Enhanced
bioremediation of the groundwater using ORC®
was implemented in December 1995.
At Fourth Plain, a release of gasoline-range
petroleum hydrocarbons beneath a product
dispenser was discovered in May 1993. At that
time, the source was repaired and contaminated
soils were excavated. Groundwater monitoring
began in 1993, and a feasibility study and
technology evaluation were conducted in 1995.
That study included a pilot test of soil vapor
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-Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
: SITE INFORMATION
; (CONTINUED)
extraction (SVE) conducted in March 1995.
Groundwater pumping constant discharge and
recovery tests also were conducted in March
1995. Enhanced bioremediation of the
groundwater using ORC® was implemented in
July 1996.
At Steve's Standard, leaks in piping and
underground storage tanks were discovered in
1994. Steve's Standard is a combination of two
sites, Steve's Standard and Golden Belt 66.
The two sites are adjacent to one another;
remediation of the contamination plume in the
groundwater beneath the sites has been
considered as a single project for this report
(referred to as Steve's Standard for this report).
At Steve's Standard, enhanced bioremediation
of the groundwater using ORC® was
implemented in July 1996.
Regulatory Context: The three sites were
cleaned up under their respective state
voluntary cleanup programs. Oversight was
performed by the respective state agency (see
Table 1), without involvement of EPA.
Information on cleanup goals for the three sites
is discussed under the Treatment System
Performance section of this report.
Remedy Selection: Enhanced bioremediation
using ORC® was selected by the lead
contractors for each of the sites on the basis of
results of an evaluation that compared
enhanced bioremediation using ORC®, air
sparging and SVE (AS/SVE), and groundwater
extraction (pump-and-treat). Enhanced
bioremediation using ORC® was selected
because it was expected to reduce the mass of
contaminants in the aquifer by more than 50
percent in only six months, thereby reducing risk
to human health and the environment from
exposure to contaminated groundwater, and
because it required a smaller capital investment
and lower operating expenses than the two
alternative technologies. Regenesis indicated
that enhanced biodegradation using ORC® was
not expected to treat the groundwater to the
federal maximum contaminant levels (MCL), but
that the treatment would reduce substantially
the dissolved-phase mass of contaminants
present in the aquifer, as well as reduce sources
characterized as moderate smear zones. Direct
injection of ORC® into the source or a line of
wells on the perimeter of the plume are the
primary methods used to achieve the stated
goals.
Period of Operation:
Balfour Road: December 1995 to present
(report covers the period
through October 1997)
Fourth Plain: July 1996 to present (report
covers the period through
October 1997)
Steve's July 1996 to present (report
Standard: covers the period through
October 1997)
MATRIX DESCRIPTION
Matrix identification
Type of Matrix Treated: Groundwater
Contaminant Characterization T2. 3. 41
Primary Contaminant Groups: Benzene,
toluene, ethylbenzene, and xylenes (BTEX) and
total petroleum hydrocarbons (TPH)
At the three sites, benzene, total BTEX, and
TPH were detected at concentrations in
groundwater ranging from 0.43 milligrams per
liter (mg/L) to 5.1 mg/L, 13.2 to 14 mg/L, and 10
to 120 mg/L, respectively. Table 2 presents the
maximum concentrations of benzene, total
BTEX, and TPH detected in groundwater at
Balfour Road, Fourth Plain, and Steve's
Standard before application of ORC®.
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
MATRIX DESCRIPTION
(CONTINUED)
Matrix-Characteristics Affecting Cost or
Becformance F2.3,4]
Table 3 summarizes the matrix characteristics
that affect the cost or performance of the
technology and the values measured. At each
site, contamination occurred in a shallow
unconfined aquifer that consisted of a sandy
and clayey mixture and ranged in thickness
from 7 to 18 feet. As shown on Table 3, Fourth
Plain had a relatively high groundwater velocity.
According to Regenesis, the vendor of ORC®,
higher groundwater velocity aids in dispersing
oxygen from an application of ORC® more
quickly over a wider area and in mixing the
oxygen with contaminants.
Table 2: Maximum Initial Concentrations Detected Prior to Application of ORC® [2, 3, 4]
!i
HiH '' V!" ' Contaminants
Benzene (mg/L)
Total BTEX (mg/L)
Total Petroleum Hydrocarbons (mg/L)
•--, ' - A 0_ l(SH» - ' ' /"
Balfour Road
0.43
Not available
10
Fourth Plain- ^
1.0
14.0
120
Steve's Standard
5.1
13.2
30
Table 3: Matrix Characteristics Affecting Cost or Performance [2, 3, 4]
>! !' ' ' ! !
"'ill1!'"', Parameters
Thickness of Aquifer (ft)
Conductivity (centimeters
per second [cm/sec])
Groundwater velocity
(ft/day)
Hydraulic Gradient (ft/ft)
Site
Balfour Road
18
0.001*
0.00076**
0.0009
Fourth Plain
12-15
0.08
1 -10
0.003 - 0.03
«* /
Steve's Standard
7-10
0.02
0.025**
0.0015
' ''
' Method of
Measurement
Visual inspection of
core samples
Slug or constant
discharge and recovery
test
Calculation using
Darcy's Law
Water level indicator
and site survey
* estimated as 0.001 cm/sec for silty clay
** calculated using estimate of porosity, 0.3
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
MATRIX DESCRIPTION
(CONTINUED) j
Table 3 (continued): Matrix Characteristics Affecting Cost or Performance [2,3,4]
~£,'* ,&a '- °^v ^r" '-^ ; fyslktt ' ^ **
fy. JC £o ,-: •- ,i;A«;,^-,
' *c £/,jK-t ^.x-4- , ••- ;•
,•*•-"-»"•* jfr^-'f** -~
3 /iMiramstirs ^ ,•;
Depth to Groundwater
(feet below ground
surface [ft bgs])
Soil Type or
Classification
pH
Porosity
Seasonal water table
fluctuation
jf^ijC;^^
i""Xn;-- ,-."•»-: . gp*3*K'•> --'••»«#*.•
' fbuj&m.*v-'
13-21
Aquifer primarily
consists of sands
and gravels, with
silty and clayey
zones (Sand/
gravel/silt
65/25/10)
6.2-7.4
20-30%
1-2 ft
li^&^^wu
7-9
Aquifer consists of
loose, medium- to
coarse-grain sand,
overlain by silty clay
soil
6.8-7.2
-25-30%
-4ft
j^'^ J-: s%;«fcVJ
i-- 4ReWj6fo&f!.*«e
fjS?|s|i;ete^;,
Water level
indicator
Visual inspection
of core samples
-
Time series data
from water level
indicator
DESCRIPTION OF TREATMENT
; SYSTEM J
Primary Treatment Technology
Enhanced bioremediation
Supplemental Treatment Technology
None
System Description and Operation f 1 ^ 2, 3. 41
Enhanced bioremediation was performed at the
three sites, using in situ bioremediation and
application of ORC®. ORC® is a proprietary
formulation based on magnesium peroxide and
is available from Regenesis Bioremediation
Products, Inc (Regenesis). The following
information on ORC® was provided by
Regenesis. When it comes in contact with
groundwater, ORC® slowly releases oxygen to
the groundwater and is converted to a
magnesium hydroxide byproduct. Regenesis
has indicated that, when hydrated, ORC® can
release oxygen for up to a year or longer (often
typically 6 months) depending on contaminant
flux and that the rate of release is a function of
the molecular matrix Regenesis produces during
synthesis and is not achieved by a coating
process.
When ORC® is used, the level of dissolved
oxygen (DO) measured in the groundwater is
raised above background levels, and the rate of
natural bioremediation is increased. The level
of DO varies according to several factors,
including:
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
DESCRIPTION OF TREATMENT
SYSTEM (CONTINUED)
• The dosage of ORC® applied to the
groundwater.
• The amount of DO consumed during
biological degradation of hydrocarbons.
• The amount of time that has elapsed since
ORC® was applied to the groundwater.
According to Regenesis, the quantity of ORC®
required for a site is based on several factors
including the estimated mass of contaminant at
the site (dissolved-phase concentration) and the
specific, properties of the aquifer such as
parasity and thickness. Regenesis indicates
that a key factor in estimating the quantity of
ORC® required is the stoichiometric quantity of
oxygen required to degrade the contaminants.
For example, fully degrading one pound of
benzene to carbon dioxide and water would
require 3 pounds of oxygen. Given that ORC®
releases 10 percent of its mass as oxygen, 30
pounds of ORC® would be required to fully
degrade one pound of benzene. Oxygen
typically is released from ORC® over a four- to
eight-month period, resulting in a sustained
increase in the amount of dissolved oxygen
available to promote aerobic biodegradation of
groundwater contamination.
Application of ORC9 T2JL41
A different method of applying ORC® to the
groundwater was used at each site, as identified
below:
• Balfour Road: wells containing filter socks
• Fourth Plain: borings containing slurry
• Steve's Standard: direct push injection
Descriptions of the systems used at the three
sites to apply ORC® to the groundwater and to
monitor the concentrations of contaminants and
DO in the groundwater are presented below.
Balfour Road - At the Balfour Road site, filter
socks containing ORC® and an inert carrier
matrix (silica sand) were applied to the
groundwater through a system of 10 wells in two
barriers, one line of four and another of six wells
installed downgradient of the source areas. The
barrier of four wells was installed closer to the
source than the second barrier. Both barriers
were arranged in a line perpendicular to the
direction of groundwater flow. Approximately
200 pounds of ORC® were applied to the
groundwater at this site. The mass of
contaminants in the aquifer was not available
for this site, and therefore the amount of ORC
applied at Balfour Road was estimated based on
the concentrations of contaminants and
properties of the aquifer. Monitoring wells (MW)
were placed 42 feet upgradient and
downgradient of each battery of wells. Monthly
monitoring of DO, benzene, and TPH was
conducted.
MW SB-43A was installed to monitor
groundwater downgradient of the battery of
ORC® wells nearest to the source of
contamination, and MW SB-37A was installed to
monitor groundwater downgradient from the
battery of wells farther downstream from the
source of contamination.
Fourth Plain - At the Fourth Plain site, a fence
of 15 boreholes (borings) at 10-foot spacing was
drilled near the upgradient edge of the
anaerobic core of the contaminant plume. The
borings were drilled to about 25 feet bgs and
each was filled from about 10 ft bgs to 25 ft bgs
with a slurry containing approximately 70
pounds of ORC®. The oxygen released by the
ORC® was transported to the anaerobic core of
the contaminant plume by the natural flow of
groundwater at the site. The site initially was
estimated to have approximately 33 pounds of
dissolved-phase contaminant (BTEX) in the
groundwater; on the basis of the 30 to 1 ratio for
ORC® to dissolved-phase contaminant
discussed earlier in this report, approximately
1,000 pounds of ORC® would be required to
treat the groundwater at the site. The 15
borings drilled at the site contained a total of
approximately 1,000 pounds of ORC®(70 Ibs x
15 wells). MWs were located on site and
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
DESCRIPTION OF TREATMENT
; SYSTEM (CONTINUED)
approximately 90 to 120 feet downgradient of the
site. The MWs were monitored monthly for DO,
BTEX, TPH, and pH.
Steve's Standard - At this site, a total of 2,325
pounds of ORC® slurry was injected into the
groundwater with a Geoprobe™ (direct-push
technology). Slurry was injected at
approximately 118 points at the site, at an
injection pressure ranging from 50 to 100 pounds
per square inch (psi), on a rectangular grid
pattern. Similarly to Balfour Road, the mass of
contaminants in the aquifer was not available for
this site, and therefore the amount of ORC
applied at Steve's Standard was estimated
based on the dissolved-phase concentrations of
contaminants and properties of the aquifer.
Approximately 50 MWs provided monitoring of
the performance of the system at Steve's
Standard. The site was monitored periodically
fora variety of parameters, including BTEX, TPH,
and DO. MWs were located throughout the site
and were used to measure the concentrations of
contaminants within source areas (for example,
MW-10 at Steve's Standard and OB-06 at
Golden Belt 66) and at locations downgradient of
the source areas (for example, MW-8 and MW-
15).
Operating Parameters Affecting Treatment
Cost or Performance
Operating parameters that affect cost or
performance include the number of points at
which ORC® is introduced (ORC® source points),
the screened intervals of source points, the
spacing of the source points (if using socks and
wells), the dosage of ORC®, and background and
operating concentrations of DO. Table 4
presents the major operating parameters that
affect cost and performance for the technology
and the values measured for each of those
parameters.
Table 4: Operating Parameters Affecting Cost or Performance [2,3, 4]
»\* *? M.' f'y-'-' V A''" " -»•' —
^ //* '-" s> Parameter' _^ .x^v "' -
Method of Application
Number of Source Points
Screened Interval
(ft below ground surface)
Source Point Spacing (ft)
Dosage of ORC® (Ibs/well)
Dosage of ORC® (total Ibs applied)
Background Dissolved Oxygen
Concentration (mg/L)
's •,:;C. ( - j;_/r- ' -_.-fj4^
•" Cl9lrOdir^vlO@IU
Wells filled with ORC®
filter socks
1 0 wells
10 -25 and 30 -33
20
20
200
<1
;^-*t*» ^£7 :-
*>''^&!*tap$tfrl -
Borings filled with
slurry
1 5 borings
10-25
10
70
1,000
1 -4
J.ris:"c: :/: r«
J^teve's-Standard 'V
Geoprobe™ injection
of slurry
118 injection points
10-25*
5-10
20
2,325
0-2
* There is no screened interval for a Geoprobe direct-push technology; the value given represents tne aeptn oeiow
the surface of the water table at which ORC® was injected at a pressure ranging from 50 to 100 pounds per
square inch.
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM
PERFORMANCE
Cleanup Goals F2.10,12]
The three sites were remediated under their
respective state voluntary cleanup programs.
The following is a discussion on how the
remediation objectives were established for
each site.
The cleanup goals identified for the Balfour
Road site were groundwater drinking-water
standards; however, no specific numerical
standards were provided by Santa Fe Pipeline
Partners. Federal groundwater drinking
standards at 40 Code of Federal Regulations
(CFR) 141.61 include an MCL for benzene of
0.005 mg/L
The cleanup goals for the Fourth Plain site
identified by Environmental Partners, Inc. were:
• Benzene, 0.005 mg/L
• Total BTEX, 0.095 mg/L
• TPH, 1.0 mg/L
The Fourth Plain site was remediated under the
state of Washington's Independent Remedial
Action Program (IRAP) that allows site owners
to manage site cleanups independently. Under
the IRAP, managed by the Washington State
Department of Ecology, the state does not
provide oversight or direction to site owners on
the appropriateness of their remedial
approaches. Instead, under the program, the
state provides a letter requiring "no further
action" when a site owner provides to the state
sufficient evidence that cleanup levels have
been met and that the site no longer represents
a threat to human health and the environment.
Because the aquifer at the site was a source of
potable water, as defined by the state of
Washington, and because a surface-water body
was immediately down-gradient from the site,
the cleanup level identified for benzene was the
MTCA cleanup level of 0.005 mg/L. The
cleanup level for TPH was established for
aesthetic reasons; no risk-based cleanup level
was identified for TPH.
No cleanup levels were established for the
Steve's Standard site. Remediation of the
Steve's Standard site was conducted as a pilot
test by the Kansas Department of Health and
the Environment (KDHE) to determine whether
ORC® could be used as a cost-effective method
of remediating groundwater contaminated with
hydrocarbons. As such, it was intended to
evaluate the effectiveness of ORC® rather than
to achieve a specified cleanup goal for the
groundwater. The application also was intended
to identify design parameters needed to
optimize an ORC® application while attracting
only minimal attention in the neighboring
community. It was funded partially by the State.
Treatment Performance Data
Performance data collected for these three sites
are summarized in Tables 5 through 8. Table 5
identifies the number of MWs, locations of
MWs, frequency of sampling, and method of
analysis for each site. Tables 6, 7, and 8
summarize analytical data for benzene, total
BTEX, TPH, and DO for selected MWs at each
of the three sites. Figures 1 and 2 present
graphically the data shown on Table 6 for
Balfour Road.
None of the sites reported any exceptions to the
quality assurance and quality control plans.
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-Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEMj
PERFORMANCE (CO;NTINIJED)
Table 5: Performance Data Sampling [1,2,3]
llPlpg |hf orniation
Number of MWs
Locations of MWs
Frequency of Sampling
Method of Analysis
•£+ „ .^Balf ougjRoad ^ /"""
4 (on site)
One Well up- and one
down-gradient of each of
the two barriers of ORC®
wells
Monthly
YSI 55 (DO)
801 5/8020 (organics)
' ^PpOTrth Plafn ./"T.,
1 0 (on site)
Up- and downgradient
of the ORC® barrier of
borings
Quarterly
Hach AccuVac (DO)
Hydrocarbon Methods
«.•;- r'Stey§'s™Standardi ^T
^\»^ ^ ;>" » 1 (' **
Approximately 50
Throughout the application
area and on the perimeter of
the property
Week, month, two-month
(doubling period between
sampling events)
Hach AccuVac (DO)
Method 8260 (BTEX)
OA-1 (TPH)
Table 6: Summary of Treatment Performance Data for the Balfour Road Site (mg/L) [2]
December 1995*
January 1996
February 1996
March 1996
April 1996
May 1996
f && ^•.f^ftSB-^^.-^r;^.-
rWB4izen|tf '.
NR
0.43
0.41
0.25
0.11
0.19
^;;r^p6;.;.^f ',
0.77
1.75
0.87
3.40
1.19
1.69
,r; . .*-; ^well
">,, Benzene _^f
NR
0.080
0.093
0.0035
0.0028
0.0014
!^4WS*^-. • /f
^ ^-V^13^""^/-*"
NR
1.29
1.30
3.32
1.92
2.47
= ORC® socks placed in wells
NR = Not reported
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM
PERFORMANCE (CONTINUED)
Figure 1. Summary of Monitoring Data. SB-37A, Balfour Road [2]*
SB-37A
Nov-95 Oec-95 Dec-95 Jan-86 Feb-96 Feb-96 Mar-96 Apr-96 Apr-96 May-96
I
o
I
Figure 2. Summary of Monitoring Data. SB-43A, Balfour Road [2]*
SB-43A
'-:---V:\-.-,ri>---'/' ". T .' '•'"''"'-'"^i^^^'V
^npiinnt ;;;*!!;;$
i; iiiii ' i i «!i»! :ii «i'i n: nil.!' i 'iint'i iliiiiii liiliiiiipiii'!! I |K»: iiftiiH i! MI!
;mmApin;,11:;;.;1 ^;s*m is'iim,;'"ik!" ^t!"_ jj ''^™":"-t^_'^*,
• " • -
Nov-95 Dec-95 Dec-95 Jan-96 Feb-96 Feb-96 Mar-96 Apr-96 Apr-96 May-96
Cleanup goal for benzene was 0.005 mg/L.
U.S. Environmental Protection Agency
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•Enhanced Bioremediation at Balf our Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM!
PERFORMANCE (CONTINUED)
Table 7: Summary of Treatment Performance Measured using a Geometric Mean
for Fourth Plain Site (mg/L) [17]*
ifriJfaatS- Vi'
July 1996"
October 1996
January 1997
•;' -H -.-*•" ,B,fenzene^-l- V*'7
< <* -^H? V
0.053
0.029
0.032
r«,ir f gtaljBTix" ' «^s
0.976
0.481
0.850
g ,;;|;;:Tp:w0Rdl,::;%
11.10
6.90
6.16
= Calculated based on data from 6 monitoring wells.
Table 8: Summary of Treatment Performance Measured using a Geometric Mean
for Steve's Standard Site* (mg/L) [4, 20]
i^>,-BI%fV,,rj
July 1996**
November 1996
February 1997
August 1997
November 1 997
§^__ J™5fiei^ne" ,,^::, \\
0.18
0.04
0.03
0.11
0.11
r|f ^ J£$otal BlilEXj^^' j8!
0.66
0.14
0.06
0.27
0.30
y>.^' ' •r$$iim&:^jf£-!
,. ~ •- ^ '>,,!&,? '!;&'" ^Vi-V &?>" "**'' s" ,
4.1
2.5
2.6
2.6
2.5
= Based on 17 monitoring wells
** = ORC® injected
NS = Not Sampled
Performance Data Assessment
This section presents a discussion of the data
on concentrations of contaminants for each of
the three sites. Where possible, the geometric
mean of wells at each site was evaluated to
provide an indication of the trend in contaminant
concentrations at the site.
Balfour Road. Table 6 and Figures 1 and 2
show the results of monitoring from December
1995 to May 1996 for benzene and dissolved
oxygen at two MWs at Balfour Road located
downgradient of the barrier of the ORC® wells.
Figures 1 and 2 show that, as of May 1996,
concentrations of benzene were reduced by
more than 50 percent in six months. In well MW
SB-43A, closest to the source of contamination,
concentrations of benzene were reduced from
0.080 mg/L to 0.0014 mg/L, which is below the
cleanup goal of 0.005 mg/L In the well,
concentrations of DO varied from 1.29 to 3.32
mg/L. In well MW-SB-37A, farther from the
source of contamination, concentrations of
benzene were reduced 56 percent from 0.43
mg/L to 0.19 mg/L. In that well, concentrations
of DO varied from 0.77 to 3.40 mg/L.
Fourth Plain. At the Fourth Plain site,
concentrations of contaminants were reported in
six MWs located throughout the plume (MW-4,
6, 7, 9,11,14). During baseline monitoring of
the groundwater at the site (July 1996), wells in
this area were shown to have the highest
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-Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM
PERFORMANCE (CONTINUED)
concentrations of benzene, total BTEX, and
TPH-G, and the lowest concentrations of DO.
Table 7 shows the geometric mean
concentrations of benzene, total BTEX, and
TPH-G measured in these wells in July 1996,
October 1996, and January 1997, covering
approximately 180 days after the application of
ORC®. Over that 180-day period, the geometric
mean concentrations of benzene, total BTEX,
and TPH-G decreased by 45, 51, and 38
percent after 90 days, and 38,12, and 44
percent after 180 days, respectively.
Background concentrations of DO at the Fourth
Plain site ranged from 1 to 4 mg/L, as shown in
Table 5. Before application of ORC®, the anoxic
core of the plume extended over an area of
approximately 1 acre, with a concentration of
DO in that area of less than 0.3 mg/L. The
anoxic core of the plume had the highest levels
of BTEX and TPH; MW-7 was located within the
anoxic core area. The concentrations of DO in
the area increased to levels ranging from 2.6 to
4.9 mg/L during the first 90 days after
application of ORC® and continued to rise to a
maximum of 7.8 mg/L, reached 180 days after
application of ORC®.
Steve's Standard. Table 8 summarizes the
results for a geometric mean of 18 of the MWs
at this site. The monitoring data cover
approximately a 16-month period after the
application of ORC®. A photo-ionization
detector (PID) analysis conducted in early 1997
identified a continuing source of hydrocarbons in
the subsurface at this site. [20] The PID data
were used to develop a plot of hydrocarbon
concentrations in the subsurface which indicated
a continuing source near the OB-6 boring. Over
the first seven months after application of ORC
(July 1996 - February 1997), concentrations of
benzene, BTEX, and TPH-G were reduced;
over the next nine months, concentrations
appeared to stabilize or rise slightly. During the
first seven months, concentrations for benzene,
total BTEX, and TPH-G were reduced 83, 91,
and 36 percent, respectively, while overall from
July 1996 - November 1997, concentrations
were reduced 39, 55, and 39 percent,
respectively.
The concentration of DO throughout the site
ranged from 0 to 6 mg/L over the period from
July 1996 to February 1997. By February 1997,
the concentration of DO was measured as 0
mg/L for 80 percent of the MWs.
The vendor supporting the KDHE (Terranext)
concluded the following about the effectiveness
of ORC at the Steve's Standard site:
• the use of ORC stimulated aerobic
biodegradation of petroleum constituents to
almost non-detect levels in areas around the
petroleum release source areas
• total BTEX levels in wells hydraulically
downgradient of the source areas have
continued to decrease
• total BTEX levels in source areas increased,
thus indicating that the total mass of BTEX
in these areas is greater than was estimated
during the design of ORC injection
Estimate of Mass of Contaminants
Degraded.
In 1997, Regenesis commissioned Principia
Mathematica, a groundwater modeling firm, to
model two of the sites (Fourth Plain and Steve's
Standard) to estimate the mass of contaminants
degraded in the aquifers. As mentioned in the
previous discussion of performance data, a
photo ionization detector identified a continuing
source below Steve's Standard. This
complicates the interpretation of modeling
results for Steve's Standard; therefore, only
modeling results for Fourth Plain are presented
below. Table 9 presents a summary of the
modeling results, including assumptions applied
in the modeling, and mass of contaminants
degraded. Approximately 280 pounds of TPH
were degraded in six months at this site.
Table 10 shows a comparison of the mass of
ORC® dosage applied at Fourth Plain with the
mass of BTEX degraded. Approximately 30 Ibs
of ORC® were applied for each pound of BTEX
degraded.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
24
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM
PERFORMANCE (CONTINUED)
Table 9: Summary of Modeling Results for Estimating Mass of Contaminants Degraded [13]
;\-tr f - ?Estimate"d Quantity!/ _ & "
Area (ft2) (see assumptions)
Mass of Benzene Degraded (Ibs)
Mass of Total BTEX Degraded (Ibs)
Mass of GRO-TPH Degraded (Ibs)
,<"" ' -•; Fourth Plain .,- -.,:>-
•^ a. - «, , 1 ti* <.,&* J , ,£»,* SK f *» 1
20,400
1.8
32.2
281.5
Assumptions:
• Area defined by 10 mg/L isopleth
• Porosity = 0.3 and density of water = 28.3 kg/ft3
• Affected thickness of aquifer =10 feet
Note: Calculations are based on a logarithmic Kriging analysis fitting a surface to the available data points and saving the fitted
surface to a finite difference grid. Volumes used in the analysis are a function of the areal extent of the 10 mg/L concentration
isopleths times a 10 -foot-thick contaminated zone with a porosity of 0.3. In addition, volumes presented here assume a low
groundwater velocity over a short period, resulting in only one volume of throughput. (It is likely that, because groundwater
velocity at Fourth Plain is higher than at Steve's Standard, the volume used in this analysis for Fourth Plain was
underestimated.)
Table 10: Ratio of ORC® Dosage to Mass of BTEX Degraded [2,3, 4,13,18]
^ ^"^ '"4x \ ' —» J?**£V . * * '*°|£V? ,< ''^/
" —1 • §• .« ''^ *T sf^ * »v$tW8iJS(' ^..V^TOF '• ^ - ^- ,<•*$:
Mass of ORC® Dosage (Ibs)
Estimated Mass of BTEX Before Application (Ib)
Mass of Total BTEX Degraded (Ibs)
Ratio of ORC® Dosage to Mass of BTEX Degraded
;. -;v ;^FMrtftPI>!tK ^:K,^ -
1,000
33
32.2
31.1
Recent Activities MO. 11 r 12]
As of October 1997, the cleanup goals
described above had not been met at either the
Balfour Road or Fourth Plain sites; however the
geometric mean concentration and mass of
benzene, total BTEX, and TPH had been
reduced by approximately 50 percent in the
aquifers in only 6 months for roughly $50,000
per site. In addition, at the Steve's Standard
site, the concentration and mass of benzene,
total BTEX, and TPH had been reduced in
portions of the aquifer. Recent activities at the
three sites are discussed below.
Balfour Road SFPP divided the site into two
areas, referred to as north of Balfour Road and
south of Balfour Road, for requesting closure
letters from the state. For the area north of
Balfour Road, a single ORC® source well
contained benzene at 0.15 mg/L. There has
been no reapplication of ORC® since the original
application (December 1995). The vendor of
the treatment indicated that it is likely that there
will be a second application of ORC® in the
affected well and that the site will request from
the state a letter for no further action at that
time. According to the vendor, for the area
south of Balfour Road, SFPP conducted further
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
PA
25
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
TREATMENT SYSTEM
PERFORMANCE (CONTINUED)
COST OF THE TREATMENT
SYSTEM
activities in the summer of 1997 to characterize
the levels of contamination in the soil and
groundwater at the site. The results of these
activities revealed additional contamination in a
utility trench located along the boundary of the
area. The contamination had not been detected
previously. SFPP had not yet identified an
appropriate remedial action for the areas south
of Balfour Road.
Fourth Plain As shown above, the
concentrations of benzene, total BTEX, and
TPH had not met the cleanup levels for the site
after six months of treatment. Environmental
Partners Inc. stated its belief that the application
of an additional 200 pounds of ORC® per
quarter for a period of 1.25 years (1,000 pounds
of ORC® total) would help achieve the cleanup
goal. The cost of the additional effort was
estimated to be an additional $50,000. The
references available do not provide information
about whether the additional treatment was
being performed.
Steve's Standard Jacobs Engineering Group
indicated that the dissolved-phase plume was
reduced in volume following application of
ORC®, but that elevated concentrations of
hydrocarbons remained at one location at the
site. In September 1997,1,500 pounds of
ORC® were injected into the aquifer, at a cost of
$25,000; samples of groundwater were collected
from the location in November 1997 to evaluate
the concentrations of hydrocarbons remaining
after that latest application of ORC®. As shown
in Table 9, concentrations had not changed
much from August to November 1997.
Procurement Process 12. 3. 41
At each site, the site owner chose a prime
contractor to be responsible for site
management. That contractor entered into
subcontracts with other firms, such as
Regenesis, to help with design and construction
of treatment systems for enhanced
bioremediation, including the use of ORC®. No
information is available that indicates whether
the prime contractors or subcontractors were
selected through a competitive bidding process.
Costs for the Treatment System [2, 3, 4]
Table 11 summarizes the actual costs of
enhanced bioremediation, including use of
ORC®, at the three sites. All cost data were
solicited and collected from the contractor that
performed the work. Total costs for the three
sites varied by a factor of 2.5, with costs at
Fourth Plain the lowest ($37,300), and those at
Steve's Standard the highest ($96,187). Steve's
Standard covered three times the area,
including two service stations (As discussed
earlier, Steve's Standard referred to in this
report comprises both the Steve's Standard and
Golden Belt 66 sites). The costs of individual
elements of the projects are presented in
Table 12.
The costs for installation of wells at Balfour
Road were high, compared with those at the
other two sites (where borings and direct push
technology were used). According to SFPP,
Balfour Road used a more expensive method of
application of ORC® to facilitate use of air
sparging as a contingency if application of
ORC® did not meet goals of the project (the
ORC® wells could be converted to sparging
wells). The costs of site work and installation of
wells at Fourth Plain are less than those for the
other two sites because the site operator used
some MWs that had been installed for site
characterization in the ORC® application
system.
U.S. Environmental Protection Agency
— — . Office of Solid Waste and Emergency Response
fcKA Technology Innovation Office
26
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
COST OF THE TREATMENT
SYSTEM (CONTINUED)
Vendor Input on Costs M91
The primary costs of using ORC® are those for
the installation of ORC® source points, the
amount of ORC® applied, and the amount and
type of monitoring required. Contaminant mass,
hydrogeology of the aquifer, and groundwater
flow rate are the most significant parameters
that affect those costs because they determine
the spacing of the source points, the number of
source points required, and the amount of ORC®
to be applied. Monitoring costs will depend on
the regulatory requirements and are beyond the
direct control of the vendor.
Table 11: Summary of Cost Data [2,3, 4]
;*>- '^ ,-f Cleanup Apf^iy-^ •*"';'"" 1 ^pa|fdiir;Roail *
* Fourfrj Plain 1'" StfW's Standard*^
- - '^*^ •"• <-*,,- j*
Treatment Activities ($) " ^ * ' ^?< >^\ " ;^'C;' *~*;/' 'f ' "C '*
Site Work and Well Installation
ORC®
Operations
Monitoring3
Treatment Subtotal
25,488
6,520
1 ,500
-
33,508
7,200
9,900
18,600
-
35,700
* ---- ~ f ',-+ ^
37,126
23,599
6,046
26,668
93,439
u ?'',**$ -* ''' ':Sw*r*r*mentA^ies^''^- ^ 7 ^ -* - v^
Decontamination
Site Restoration
Demobilization and Disposal
After Treatment Subtotal
4,900
1,000
2,200
8,100
500
500
600
1,600
2,748
-
-
2,748
^ '• :: :;'*' * /a y\^" ,_,^ ^^' "-""jr ^ r '-'\^* / ' -:
TOTAL COST
$41,608
$37,300
$96,182
• For Balfour Road and Fourth Plain, this cost was not provided separately from operating costs.
** Steve's Standard comprises two adjacent facilities.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
PA
27
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
SITE CONTACTS
Table 12 presents the contacts for each of the three sites.
Table 12: Site Contacts
I|" ' Balfour Road "- "/ - '_ ' ;,„,/'
Site Management/Design:
Mark Sandon
Santa Fe Pipeline Partners L.P.
1100 Towne & Country Road
Orange, CA 92868
(714) 560-4867
Construction:
Levine-Fricke
2001 Douglas Boulevard
Roseville, CA 95661
(916) 786-0320
State Contact:
Joel Weiss
California Regional Water Quality Control Board
Central Valley Region
(916)255-3077
Design (Additional):
Craig Sandefur
Regenesis Bioremediation Products, Inc.
271 30A Paseo Espada, Suite 1407
San Juan Capistrano, CA 92675
(714)443-3136
it , Fourth Plai(n s; " , , ' r ' '< ' '- -
I Site Management:
1 Joseph L. Glassman
1 Environmental Insurance Management, Inc.
1 512 North Oakland Street
Arlington, VA 22203
Construction/Design:
Thomas Morin
Environmental Partners Inc.
10940 NE 33rd Place, Suite 110
Bellevue, WA 98004
(206) 889-4747
Iii n
Site Management:
Roger Lamb
Jacobs Engineering Group Inc.
8208 Melrose Drive, Suite 210
Lenexa, KS 66214
(913)492-9218
Construction:
Roger Lamb
Jacobs Engineering Group Inc.
8208 Melrose Drive, Suite 210
Lenexa, KS 66214
(913)492-9218
State Contact:
Carol Fleshes
Washington Department of Ecology
NW Region, Mail Stop PV11
Olympia, WA 98504-8711
(206) 649-7000
Design (Additional):
Steve Koenigsberg
Regenesis Bioremediation Products, Inc.
271 30A Paseo Espada, Suite 1407
San Juan Capistrano, CA 92675
(714)443-3136
Steve's Standard , , / "' 'y/, '' "~
State Contact:
Emily McGuire
Kansas Department of Health and Environment
Bureau of Environmental Remediation
Forbes Field, Building 740
Topeka, KS 66620
(913) 296-7005
Design:
Craig Sandefur and David Peterson
Regenesis Bioremediation Products, Inc.
271 30A Paseo Espada, Suite 1407
San Juan Capistrano, CA 92675
(714)443-3136
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
28
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
OBSERVATIONS AND LESSONS
: LEARNED '
Cost Observations and Lessons Learned
• Actual costs for enhanced bioremediation
using ORC® at the three sites ranged from
$37,300 to $96,187, with costs at two of the
three sites less than $50,000. The relatively
high cost at Steve's Standard is attributed to
the large area treated for two service
stations. The costs included activities
directly attributed to treatment, such as site
work, installation of wells, application of
ORC®, operations, and monitoring, and
activities performed after treatment, such as
decontamination, site restoration, and
demobilization and disposal.
• The factors that most affected costs at the
three sites included the amount of ORC®
applied, (e.g., 200 Ibs at Balfour Road;
1,000 Ibs at Fourth Plain; 2,325 Ibs at
Steve's Standard) the number of ORC®
source points, (e.g., 10 wells at Balfour
Road; 15 borings at Fourth Plain; 118
injection points at Steve's Standard), and
the type of equipment used to apply ORC®
(for example, the wells used at Balfour
Road were relatively more expensive than
equipment used at the other two sites).
• The firms responsible for site management
and construction compared the cost of
remediating the sites by enhanced
bioremediation using ORC® with the costs of
other technologies such as an AS/SVE
system. For example, at the Balfour Road
site, the installation and startup costs alone
for an AS/SVE system were estimated to
cost $181,077 compared to $33,508 for a
complete ORC application. At the Steve's
Standard site, the site management firm
estimated that installation and operation of
an AS/SVE system would have cost
$250,000, including $36,000 for operations.
The firm indicated that pilot tests showed
that AS/SVE would have been effective at
the site, but that it would not have been
practical to install such a system because of
limited space available for equipment and
the close proximity of residential housing.
[12]
• At the Balfour Road site, use of ORC® was
estimated by SFPP to have saved the site
owner approximately $100,000 over the cost
of AS/SVE. [2]
Performance Observations and Lessons
Learned
• At the Balfour Road site, the overall cleanup
goal was not met during the six-month
operation period of the ORC® application.
However, benzene concentrations in the
well closest to the source of contamination
were reduced by 98 percent to 0.0014 mg/L
(below the cleanup goal of 0.005 mg/L).
Benzene concentrations in a well farther
from the source were reduced by 56
percent, but concentrationd remained above
the cleanup goal.
• The six-month application of ORC® at the
Fourth Plain site resulted in a 40 percent
reduction in the mean benzene
concentration, a 45 percent reduction in the
mean TPH/GRO concentration, and a 13
percent reduction in the mean BTEX
concentration. However, the final
concentrations of all three parameters
remained above the cleanup goals.
• The application at the Steve's Standard site
was conducted by the state as a pilot test;
there were no specific cleanup goals for the
application. The geometric mean
concentrations for benzene, total BTEX, and
TPH-G were reduced by nearly 40 percent
at this site during the first seven months of
operation. However, there was a continuing
source of contamination at this site, and this
limited the effectiveness of the technology
application.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
PA
29
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
OBSERVATIONS AND LESSONS
LEARNED (CONTINUED)
• Modeling was used to estimate the mass of
contaminant degraded in the aquifer at the
Fourth Plain site. The total mass of total
BTEX and TPH degraded was 32.2 and 282
Ibs, respectively. This corresponds to a
ratio of dose of ORC® to mass of total BTEX
degraded of 31:1. The ratio identified for
the Fourth Plain site is very close to the
ratio of dose of ORC® to mass of total BTEX
degraded of 31.1. The ratio identified for
the Fourth Plain site is very close to the
ratio of 30:1 estimated on the basis of
soichiometric relationships.
• Remediation at all three sites was
conducted in relatively shallow unconfined
aquifers (less than 20 feet deep)
contaminated with gasoline-range petroleum
hydrocarbons. At Fourth Plain, the mass of
contaminants in the aquifer was estimated
to be 30 Ibs before treatment with ORC®.
The mass of contaminants in the aquifer
before treatment was not provided for either
the Balfour Road or the Steve's Standard
site. For those sites, Regenesis determined
the amount of ORC® to apply to the
groundwater on the basis of concentrations
of contaminants and hydrogeological data.
The amount of ORC® applied to the aquifers
at the three sites differed by a factor of 10,
ranging from 200 Ibs at Balfour Road to
2,325 Ibs at Steve's Standard.
• The levels of DO measured in the aquifers
at the three sites generally were higher after
application of ORC® than before its
application. The levels of DO typically
ranged from 2 to 8 mg/L within six months
after application of ORC®.
Other Observations and Lessons Learned
Regenesis has stated that it developed ORC® to
reduce the mass of petroleum hydrocarbons in
groundwater over a shorter period of time and
for a lower cost than can be achieved by
conventional technologies, and provided the
following additional observations about the use
of ORC®:
• Costs for ORC® are less than those for other
technologies such as AS/SVE or pump-and-
treat. ORC® requires less capital investment
in equipment than the other technologies
and can be deployed relatively quickly. Use
of ORC® will substantially reduce the mass
of contaminants in an aquifer, and will
control levels of contamination in source
areas, reducing risk to human health and
the environment from exposure to
contaminants in an aquifer and increasing
levels of DO in an aquifer. ORC® typically
will reduce concentrations of contaminants
in an aquifer by at least 50 percent in six
months, but is likely not the best remedy for
a site that must be remediated to meet
MCLs. In addition, ORC may be used to
remediate relatively less-contaminated
areas of an aquifer (polishing).
• Compared with other technologies, such as
pump-and-treat or AS/SVE, ORC® is a
passive technology, the implementation of
which does not require an extensive design.
• ORC® may be used not only as a treatment
barrier to reduce concentrations of
contaminants in dissolved hydrocarbon
plumes migrating off site but also as a
source control technology when injected
directly into a source.
• The effectiveness of ORC® over the long
term remains unknown. Monitoring over
two-year periods and multiple applications
will be useful in obtaining the data needed
to determine the technology's ability to
achieve cleanup goals.
• Further research on the applicability of
ORC® in more complex hydrogeological
environments is necessary. The three sites
presented in this report all had relatively
shallow, unconfined aquifers.
• ORC® provides a quick response technology
for elevating concentrations of DO and
increasing aerobic degradation processes in
groundwater over a wide area.
U.S. Environmental Protection Agency
°ff'ce °f Solid Waste and Emergency Response
Technology Innovation Office
30
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•Enhanced Bioremediation at Balfour Road, Fourth Plain, and Steve's Standard Sites
REFERENCES
1. S. Koenigsberg and C. Sandefur. 1996.
The Use of Oxygen Release Compound
(ORC®) in Hydrocarbon Risk Reduction
Protocols. Preprinted Extended Abstract.
Presented at the I&EC Special Symposium,
American Chemical Society. Birmingham,
AL. September 9-12.
2. Regenesis Bioremediation Products, Inc.
(Regenesis). 1997. Response to
questionnaire regarding Balfour Road Site.
From Steve Koenigsberg.
3. Environmental Partners, Inc. 1997.
Response to questionnaire regarding Fourth
Plain Service Station Site. From Thomas
Morin.
4. Jacobs Engineering Group Inc. 1997.
Response to questionnaire regarding
Steve's Standard and Golden Belt 66 Site.
From Roger Lamb.
5. Norris, R.; D. Wilson; and R. Brown. 1996.
The Role of Biological Migration Barriers in
the Remediation of Contaminated Aquifers.
Presented at the I&EC Special Symposium,
American Chemical Society. Birmingham,
AL. September 9-12.
6. Tedder, W.. 1996. Emerging Technologies
in Hazardous Waste Management VIII.
Preprinted Extended Abstract. Presented at
the I&EC Special Symposium, American
Chemical Society. Birmingham, AL.
September 9-12.
7. Koenigsberg, S. 1997. "Enhancing
Bioremediation." Environmental Protection.
February 1997. Pages 19-22.
8. Morin, T. 1997. Enhanced Intrinsic
Bioremediation Speeds Site Cleanup.
Pollution Engineering. February.
9. Regenesis. 1996. Oxygen Release
Compound, ORC®, Technical Bulletins
Index. August 27.
10. Environmental Partners. 1997. Letter. To
Stephen Koenigsburg. From Thomas
Morin. October 10.
11. Regenesis. 1997. Letter. To Charles
Minesinger, Tetra Tech EM Inc. From Craig
Sandefur. October 24.
12. Jacobs Engineering Group, Inc. 1997.
Letter. To Charles Minesinger, Tetra Tech
EM Inc. From Roger Lamb, Jacobs
Engineering Group Inc. October 21.
13. Regenesis. 1997. Facsimiles regarding
results of modeling. October 7.
14. Regenesis. 1997. Colorized Isopleth Maps
and Selected Cross-Section Diagrams of
Fourth Plain and Steve's Standard.
October.
15. Regenesis. 1997. Facsimiles regarding
ORC® modeling and site information.
May 30; June 4; and June 16.
16. Jacobs Engineering Group Inc. Facsimile
regarding Steve's Standard site. June 2,
1997 and August 1, 1997.
17. Regenesis. 1997. Facsimile regarding
responses to additional questions
concerning ORC® sites. May 6,1997.
18. Principia Mathematica. 1997. Facsimile
regarding correction of modeling data.
From Steve Cole. November 21.
19. Koenigsberg, S. Regenesis. 1997.
Material and Comments Provided in
Response to Draft Report Dated December
1997. December 2.
20. Koenigsberg, S. Regenesis. 1998.
Material and Comments Provided in
Response to Draft Report Dated February
1998. March 26.
Preparation Of The Analysis
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 Tetra Tech EM Inc. under EPA
Contract No. 68-W4-0004.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
PA
31
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32
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Coagulation/Flocculation/Dissolved Air Flotation and Oleofiltration™ at
the Coastal Systems Station, AOC 1, Panama City, Florida
33
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Coagulation/Flocculation/Dissolved Air Flotation and Oleofiltration™ at
the Coastal Systems Station, AOC 1, Panama City, Florida
Site Name:
Coastal Systems Station, AOC 1
Location:
Panama City, FL
Contaminants:
Total Petroleum Hydrocarbon
(TPH)
- concentrations in the bioslurper
process wastewater ranged from
5,000to21,000mg/kg
Metals - copper, lead, zinc
Period of Operation:
August 1997
(Demonstration conducted for a
total of 448 hours)
Cleanup Type:
Demonstration
Vendor:
CRF/DAF:
Great Lakes Environmental Inc
315 S. Stewart Ave
Addison, IL 60101
Oleofiltration™:
North American Technologies
Group Inc
4719 Bellaire Blvd, Suite 301
Bellaire.TX 77401
Additional Contacts:
Naval Facilities Engineering
Service
1100 23rd Avenue
Port Hueneme, CA 93043-4301
Technology:
CRF/DAF (Chemical reaction and
flocculation and dissolved air
flotation):
- DAF system (Model DAF-5) was
a skid-mounted unit containing a
flotation chamber, including a
skimmer, sump, and air dissolving
tank
- CRF system (Model CRF-15)
included a two-stage chemical
reaction tank, a polymer mix
preparation tank, pumps, and
mixers
- Oleofiltration™ treatment system
included a conventional oil/water
separator, coalescing unit, and
ceramic granule filtration system
Cleanup Authority:
RCRA
Regulatory Point of Contact:
Information not provided
Waste Source: Fire-fighting
training using ignitable
hydrocarbons
Type/Quantity of Media Treated:
Wastewater - 126,400 gallons
Purpose/Significance of
Application: Demonstrate the
effectiveness of CRF/DAF and
Oleofiltration™ in treating TPH
and metals from wastewater from a
full-scale bioslurper system
Regulatory Requirements/Cleanup Goals:
The objective of the demonstration was to determine the ability of the two water treatment systems to remove
emulsified oil/grease from a bioslurper wastewater stream. A secondary objective was to determine if the
TRF/DAF system could effectively remove metals.
34
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Coagulation/Flocculation/Dissolved Air Flotation and Oleofiltration™ at
the Coastal Systems Station, AOC 1, Panama City, Florida (continued)
Results:
- The CRF/DAF system removed more than 98% of TPH from the wastewater stream containing an influent
concentration of 5,000 mg/kg TPH as compared to the Oleofilter™ which removed between 56% and 90% TPH.
- The CRF/DAF system removed 98.9% of lead and zinc and more than 90% of copper from the wastewater
stream whereas the Oleofilter™ removed 75% lead and 71% zinc. In addition, the percent removal of metals by
the Oleofilter™ was reported to have varied significantly from sample to sample. Copper concentrations in the
influent to the Oleofilter™ were below detection limits; therefore, a percent removal could not be calculated.
Cost:
- The results of the demonstration were used to estimate full-scale costs. Short-term (6-month) operating costs
were calculated for both systems, assuming that the equipment was leased. The estimated cost per month to lease
and operate each system was $7,580 for the CRF/DAF (for a six-month total of $45,500) and $3,650 for the
Oleofilter™ (for a six-month total of $21,900)
- Excluding lease rates, the monthly operating costs for the CRF/DAF and Oleofilter™ systems are estimated to
be $3,650 and $1,150, respectively.
- Based on these estimates, the CRF/DAF system costs about twice as much to lease and operate as the
Oleofilter™ system.
Description:
The Coastal Systems Station is located in Panama City, Florida along the St. Andrews Bay. AOC 1 is a former
fire-fighting training area used from 1955 to 1978, where waste oil and other ignitable such as diesel, gasoline,
JP-5 jet fuel, and paint thinner were used during fire training exericse. An estimated 63,000 gallons of flammable
hydrocarbons were in this area and light, nonaqueous-phase liquid (LNAPL) was identified during the RCRA
Facility Investigation. The Navy selected bioslurping to remove LNAPL from the subsurface. During aipilot-
scale test, it was determined that the wastewater generated from the system contained high levels of emulsified
hydrocarbons as well as high concentrations of copper, lead, and zinc; high levels also were expected in (the full-
scale bioslurping system. To identify a cost-effective treatment technology for the full-scale bioslurping system
wastewater, the Navy selected two technologies, CRF/DAF and Oleofiltration™, for demonstration. The
concentrations in the bioslurper wastewater during the demonstration were TPH as high as 27,000 ppm, and
copper, lead, and zinc as high as 228 ppm, 1,430 ppm, and 6,210 ppm, respectively.
The CRF system included a two-stage chemical reaction tank, a polymer mix preparation tank, pumps, and
mixers. The skid-mounted DAF system included a flotation chamber, including a skimmer, sump, and air
dissolving tank. The 10 gpm capacity Oleofiltration™ treatment system included a conventional oil/water
separator, coalescing unit, and ceramic granule filtration system. For the CRF/DAF system, the influent water
flow rate was 1.5 to 6.5 gpm. The retention tune for the two-stage CRF unit was 37 to 160 minutes for Stage 1
and 22 to 94 minutes for Stage 2. The retention tune for the DAF unit was 13 to 55 minutes. For the
Oleofiltration™ treatment system, the influent flow rate ranged from 5 to 7.5 gpm with a retention tune of 25 to
37 minutes.
35
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Section 1.0: SITE INFORMATION
The Coastal Systems Station (CSS) Panama City is located along the St. Andrew Bay in
Panama City, Florida. The site, Area of Concern (AOC) 1, currently is being managed under the
Resource Conservation and Recovery Act (RCRA). The site is bound by parking to the west and south,
by shipping and receiving facilities to the east, and by woodland and Solid Waste Management Unit
(SWMU) 9 to the north. AOC 1 is a former fire-fighting training area that was operational from about
1955 to 1978. Primarily waste oil was used during fire-fighting training exercises; however, other
materials that were reportedly ignited include diesel, gasoline, JP-5 jet fuel, and paint thinner. It is
estimated that approximately 63,000 gallons of flammable hydrocarbons were released and ignited
throughout the 23-year operation of this facility (ABB, 1995). AOC 1 was graded, paved, and used as an
open storage area once it ceased to be used as a fire-fighting training area in 1978.
An initial assessment study (IAS) was performed by C. C. Johnson and Associates in 1985 to
collect background information on chemicals used at the CSS and at specific sites where chemicals and
wastes were known to have been used, stored, or disposed of. The IAS indicated the possibility of
contamination at AOC 1. A confirmation study performed by Environmental Science and Engineering
was begun in 1987 to confirm the results of the IAS. The results of the study recommended future, more
detailed investigations at AOC 1 (ABB, 1996). In 1991, ABB Environmental Services initiated a RCRA
Facility Investigation (RFI). The purpose of the RFI was to evaluate and characterize releases at the
CSS. The presence of a light, nonaqueous-phase liquid (LNAPL) was identified at AOC 1. As a result
of the findings of the RCRA investigation, ABB Environmental Services performed additional
investigative work to determine the extent of the LNAPL contamination at AOC 1 and recommend an
appropriate treatment technology. In 1994, 15 piezometers were installed to determine the extent of the
LNAPL plume. The maximum apparent LNAPL thickness of 1.5 ft was measured immediately southeast
of the center of the fire-fighting training area (ABB, 1996). The approximate extent of the plume as
delineated by ABB in 1994 is shown in Figure 1.
ABB recommended a product recovery system consisting of two LNAPL collection trenches
with a number of sumps containing product recovery pumps as an interim corrective measure at AOC 1.
Because these types of recovery systems can operate for years without achieving cleanup goals, the Navy
investigated other cost-effective treatment technologies. The Navy elected to implement bioslurping - an
innovative treatment technology to remove LNAPL from the subsurface. Previous investigations
(Battelle, 1997) have indicated that bioslurping recovers LNAPL about 10 times faster than conventional
technologies such as skimming or dual-pump drawdown.
Battelle Memorial Institute performed a pilot-scale bioslurper test at AOC 1 during October
1996. Results indicated that bioslurping would be an appropriate remediation technology for
implementation at AOC 1. However, the wastewater produced during the pilot test contained high levels
of emulsified hydrocarbons and high concentrations of copper, lead, and zinc. Total petroleum
hydrocarbon (TPH) concentrations in the wastewater ranged from 1,500 to 6,200 ppm. In addition,
levels of copper, lead, and zinc as high as 69, 190, and 1,900 ppb, respectively, were observed. It was
expected that water extracted during the full-scale bioslurper operation would exhibit similar
characteristics. In an effort to select a cost-effective water treatment technology to treat the water
generated by the full-scale bioslurper system, two technologies, coagulation/fiocculation combined with
dissolved air flotation and OleofiltrationTM, were selected and demonstrated during startup of the full-
scale bioslurper system. Information regarding the site and the evaluation of these technologies is
presented in Table 1.
36
-------
Estimated Extent of Contamination
at AOC 1, CSS Panama City
AOC 1 CSS PANAMA CITY, FLORIDA
Figure 1. Extent of LNAPL Plume at Area of Concern 1
37
-------
Table 1. Site and Technology Information
Site:
Activity that Generated
Contamination:
Standard Industrial
Classification Code:
Site Characteristics
Media treated:
Contaminants Treated:
Treatment Systems (Water):
Cleanup Type:
Period of Evaluation:
Total Volume of Water
Treated During Demo:
Area of Concern 1 at the Coastal Systems Station, Panama
City, Florida
Fire-fighting training
2869; Industrial organic chemicals not elsewhere classified
Wastewater generated by a full-scale bioslurper process
Emulsified oil/grease and heavy metals including copper,
lead, and zinc
• Coagulation/flocculation combined with dissolved air
flotation; manufactured by Great Lakes Environmental
Inc., 315 S. Stewart Avenue, Addison, Illinois 60101
• OleofiltrationTM; manufactured by North American
Technologies Group Inc, Suite 301, 4710 Bellaire Blvd,
Bellaire, Texas 77401
Implementation and evaluation of water treatment
technologies to treat wastewater generated by a full-scale
bioslurper process
448 hours of operation beginning August 1997
126,400 gallons
38
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Section 2.0: MATRIX DESCRIPTION
The matrix characteristics that affect the cost and/or performance of the water treatment
system are presented in Table 2. The process water from the bioslurper system contained a high
concentration of emulsified oil/grease. A concentration as high as 27,000 ppm was measured. During
the demonstration, the water was milky yellow in appearance and had a strong hydrocarbon odor. Metal
contaminants that were identified for removal during the demonstration include copper, lead, and zinc.
Concentrations of copper, lead, and zinc as high as 228, 1,430, and 6,210 ppm, respectively, were
measured in the bioslurper process water.
Table 2. Matrix Characteristics Affecting Treatment Cost and/or Performance
Parameter
TPH in Water (ppm)
Copper in Water (ppm)
Lead in Water (ppm)
Zinc in Water (ppm)
Total Suspended Solids (mg/L)
Influent Process Water pH
Value(s)
5,000 to 27,000
ND to 228
62 to 1,430
697 to 6,2 10
211 to 570
4.81 to 5.91
Method of Measurement
EPA Mod. 8015
EPA200.7/SW6010
EPA239.2/SW7421
EPA200.7/SW6010
EPA 160.2
EPA 150.1
ND - below detection limit
39
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Section 3.0: TREATMENT SYSTEM DESCRIPTION AND OPERATION
Two types of treatment systems were evaluated for treating the wastewater produced by the
full-scale bioslurper process. One system consisted of a chemical reaction and flocculation (CRF) tank
and a dissolved air flotation (DAF) system, manufactured by Great Lakes Environmental, Addison,
Illinois. Bench-scale tests performed on water samples collected during bioslurper pilot testing indicated
that the CRF/DAF could achieve a 99% reduction of TPH in the process water. The other water
treatment technology that was tested was an OleofiltrationTM system. The Oleofiltration™ system is a
hydrocarbon recovery technology utilizing amine-coated oleophilic granules to separate suspended and
emulsified hydrocarbons from water, manufactured by North American Technologies, Inc., Belaire,
Texas. Literature (EPA, 1995) has indicated that a 97% reduction in TPH is achievable using this
technology.
The objective of the demonstration was to evaluate the ability of the two water treatment
systems to remove emulsified oil/grease from the bioslurper wastewater stream. A secondary objective
was to determine if the CRF/DAF system could effectively remove metals, including copper, lead, and
zinc, by increasing the pH of the process water.
3.1
Treatment System Description.
3.1.1 CRF/DAF Treatment System. The CRF system (Model CRF-15) consists of a two-stage
chemical reaction tank, a polymer preparation mix tank, chemical metering pumps, constant and variable
speed mixers, and associated instruments and controllers. A schematic illustration of the CRF system is
shown in Figure 2. The aqueous effluent from the bioslurper process enters the two-stage mix tank.
Coagulation is performed in the first stage by dosing and mixing a 50% ferric sulfate solution and a 50%
sodium hydroxide solution into the process water. For optimum hydrocarbon removal the manufacturer
recommends that the pH of the process water be maintained around 6. The water then enters the second
stage where a flocculating polymer is mixed into the process water. Following the chemical addition, the
stream gravity flows into the DAF system.
The DAF system (Model DAF-5) is shown in Figure 3. The unit is skid mounted. It
contains a flotation chamber that includes a float skimmer and a float storage sump, an air dissolving
tank, and appropriate controls and meters. An air compressor is required for operation. Microscopic
bubbles are pumped into the water. The bubbles attach themselves to the floes created in the CRF,
giving them positive buoyancy that causes them to rise to the surface of the water. The skimmer skims
the solids into a temporary storage compartment mounted inside the unit. If necessary, an auger can be
installed to periodically pump out heavy solids that have settled at the bottom of the DAF unit. The
resulting solids slurry is passed into a tank where it is allowed to settle. The separated liquid is recycled
through the system. The sludge is transported off site by a waste disposal company and is recycled and
blended for heat recovery.
3.1.2 OleofilterTM Treatment System. The OleofilterTM combines a conventional oil/water
separator, a coalescing unit, and a ceramic granule filtration system. Figure 4 illustrates the concept.
Any free-phase oil present in the wastewater is removed by the oil/water separator. Water containing
emulsified oil then flows downward inside the unit's outer shell and upward past a series of coalescing
plates. Any remaining emulsified oil is removed as the water flows upward through the center of the unit
through a bed of oleophilic amine-coated ceramic granules. Over time, the Oleofilter™ bed will become
saturated with hydrocarbons. When saturation occurs, the filtering bed automatically regenerates itself
by backflushing. The wastewater and oil produced during the backflushing process is recycled through
the system. Hence, no waste products (other than reclaimed oil) are generated.
40
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..2ft.
6ft.
Chemical Reaction
Tank
Flocculation Tank
n
aai
1
A > i
Ferric
Sulfate
Addition
NaOH
Addition
410,
Chemical Reaction
Tank
o
Flocculation Tank
o
6.8 ft.
Source: Great Lakes Environmental, Inc., 1992
COAG01.CDR
. failing tKlnolosr 76 Wat
Coagulation/Flocculation Equipment
CSS PANAMA CITY, FLORIDA
PROJECT G337321-61 I DATE 10/97
DESIGNED BY
SR
DRAWN BY
VS
CHECKED BY
GBW
Figure 2. Chemical Reaction and Flocculation System
41
-------
FLOAT SKIMMER
_ _: ^- fc- EFFLUENT
AIR DISSOLVING
-H- TANK RECYCLE
Source: Great Lakes Environmental, Inc., 1991
Dissolved Air Flotation Process
CSS PANAMA CITY, FLORIDA
PROJECT G337321-61 FDATE 10/97
DESIGNED BY
SR
DRAWN BY
VS
CHECKED BY
GBW
Figure 3. Dissolved Air Flocculation System
42
-------
Concentrated Oil
Outlet (Port B)
Coalesced Oil
Treated Water -*-
Outlet/Backwash
Water Inlet (PortC)
Coalescing Plates
Note: The backwash water outlet (Port D)
is not shown in this view.
Source: Adapted from SFC 0.5x Operating Manual, 1992
. faOag Technology To Wtok
Oil/Water Inlet
(Port A)
Water for
Oleophilic Filtration
Oleophilic Granules
SFC 0.5 System Configuration
CSS PANAMA CITY, FLORIDA
PROJECT G337321-61
I DATE 10/97
DESIGNED BY
SR
DRAWN BY
VS
CHECKED BY
GBW
Figure 4. Oleofilter™ Treatment System
43
-------
Ambient Air
1
From
Extraction
Wen
Manifold
Vent
fl
Equalled
Drums
- 4-
g
H
Llqulc
Pu
To Atmosphere
i — > I i 1
Liquid Ring ' »»—'
Pump Recycle
Water Tank
Oil/Water
Separator
DeSXJNED BY
ORAKVNBY
Explanation
\fopor Stream
Fluid Stream
Denotes backflush
""" OBa^^>
VS
CHECKED BY
GBW
Full-Scale Bioslurper Design
CSS PANAMA CITY, FLORIDA
PROJECT G337321-61 I DATE 11/97 ~ fisCMBCoe
Induced Draft
Moisture Induced Di
Separator Blower
Recycled Water
. Sludge '
To Disposal
Coagulation/ I
Rocculation 8.
"Backnush Water
>~^
Progressive
Cavity
Pump
Figure 5. Full-Scale Bioslurper Process with Oleofilter™ and CRF/DAF in Series
44
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3.2 Operation. The CRF/DAF and OleofiltrationTM treatment systems were operated in
parallel. The process flow is illustrated in Figure 5. Both treatment systems require a compressed air
supply for
proper operation. A weatherproof Ingersoll-Rand reciprocating air compressor (Model 2545E10P) was
used to supply air to both processes. A pneumatic double-diaphragm pump was used to pump the
wastewater from the bioslurper process to the 2-stage CRF tank. Electronic metering pumps were used
to meter ferric sulfate and sodium hydroxide into the first stage of the tank and polymer into the second
stage of the tank. The sodium hydroxide dosage was controlled using a GLI conventional pH
combination electrode with a Model 672 pH controller with a set point range set between 8.7 and 9.2.
This high pH range was selected to induce precipitation of metals in the first stage of the CRF. The rate
of ferric sulfate and polymer addition was based on results of a bench-scale test performed on process
water samples that had been collected during the pilot-scale bioslurper test. Results indicated that a
dosage of 250 ppm ferric sulfate and 2 ppm polymer significantly reduced the concentration of
emulsified oil/water in the process water. The chemically treated water gravity fed from the second
stage of the CRF into the DAF through a schedule 80, 1.5-inch-diameter polyvinyl chloride (PVC)
transfer pipe. This pipe was later replaced with a 2-inch-diameter clear polyethylene hose; fouling of the
1.5-inch-diameter pipe with flocculated material caused the CRF to overflow with water when the
process flowrate was greater than 6 gpm.
The floes were separated from the water by introducing microscopic air bubbles into the
process stream inside the DAF. The air bubbles were introduced into a portion of treated water pumped
from the DAF into the recycle repressurization tank using a 1.5-hp GrundfosTM centrifugal pump
(Model CR2-50). A %-inch globe valve controlled the flowrate of aerated water bled into the influent
process stream. An adjustable speed drag belt skimmer was used to skim the separated floes floating on
the surface of the treated water into the sludge reservoir located in the leftmost compartment of the DAF
system. The sludge was pumped into a 2,550-gallon tank using a Va-inch-diameter ARO pneumatic
double-diaphragm pump. The treated water gravity fed into the rightmost compartment of the DAF
system. A 1-inch-diameter ARO pneumatic pump also was used to pump the water into a 325-gallon
surge tank prior to discharging it into a sanitary sewer. The sludge that accumulated inside the 2,550-
gallon tank was periodically dewatered. A VS-hp sump pump was used to pump water from the bottom of
the sludge tank into the 500-gal surge tank that provided the process water to the water treatment
processes. The operating parameters that affect the cost and/or performance for this technology are
presented in Table 3. The range of values that were measured during the demonstration are shown in the
second column.
A 10-gpm OleofilterTM was tested. The Oleofilter™ was equipped with a 1-hp
progressive cavity pump that pumped the process water from the 500-gallon surge tank into the top of
the OleofilterTM. A 1-hp centrifugal pump was used to pump the treated water out of the OleofilterTM
into the 500-gallon surge tank. The influent and effluent pump flowrates were balanced using a bypass
valve (1-inch-diameter globe valve) located on the inlet side of the progressive cavity pump. It was
originally intended that the water treated by the OleofilterTM t,e pumped into the 325-gallon treated
water surge tank (Figure 5); however, visual observations indicated that a high concentration of
oil/grease remained in the water after treatment by the OleofilterTM, Therefore, the water was recycled
back into the 500-gallon surge tank. The LNAPL that was separated from the wastewater was gravity
fed into the 360-gallon LNAPL storage tank. The operating parameters that affect the cost and/or
performance for this technology are presented in
Table 3
45
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Table 3. Water Treatment System Operating Parameters
I Parameter
Influent Water Flowrate (gpm)
Retention Time (min)
• CRF, Stage 1
• CRF, Stage 2
• DAF
Ferric Sulfate Dosage, 50%
Concentration (ml/min)
Polymer Dosage (ml/min)
pH of Treated Process Water
Average Volume of Sludge
Produced, Dewatered (gal/day)
Recycle Water Flowrate (gpm)
Recycle Pressurization Tank
Pressure (psig)
•MffVtHWWilll .1 IlilW'ifl'ifi'iT
Influent Water Flowrate (gpm)
Retention Time (min)
Differential Pressure Across
Oleofilter (psig)
Value(s)
iiSillpffi/Daf "mr '
l,t 'HJ»t(h'l[ IllL.vH. jU-WSXA'-a ^J5 ^JliUlS^to
1.5 to 6.5
37 to 160
22 to 94
13 to 55
1.2 to 23
20 to 47
8.25 to 9.26
20
10 to 18
40 to 65
ifllflp' OleoFtfter*™ *< <*
5 to 7.5
25 to 37
1.5 to 4.5
Method of Measurement
' T ,' 1 f - ' ' *( lif" '- • ' ^
i&i ^1 * V t«taff "CL. h ~. S %
Rotameter
Calculation based on flowrate
and process equipment
dimensions
Graduated cylinder
Graduated cylinder
Calibrated pH meter;
laboratory method EPA 150.1
Graduations on tank
MagnetrollM flow indicator
Pressure gauge
*/ * «/' , '., '# \\,
Rotameter
Calculation
Differential pressure gauge
The OleofilterTM was equipped with an automatic backflush system to clean the packing
media after it became saturated with hydrocarbons. It was set to activate when the pressure differential
across the packing media exceeded 5 psig. The backflush process consisted of washing the packing by
pumping treated water and compressed air through it. The wastewater produced during backflushing was
pumped back into the 500-gallon surge tank and the small volume of air generated was vented to the
atmosphere. The pressure differential remained below 5 psig during the demonstration; therefore, the
backflush process never actuated automatically. However, a manual backflush was performed several
times during the demonstration in an effort to troubleshoot and improve the efficiency of the unit.
33 Sampling and Analysis. Water samples were collected on a weekly basis; samples were
collected from the bioslurper oil/water separator effluent, the DAF effluent, and the OleofilterTM
effluent. The OleofilterTM was smit off for about 3 hours prior to collecting the DAF effluent sample so
that the partially treated stream from the OleofilterTM WOuld not dilute the influent stream to the
CRF/DAF, thereby biasing treatment results. Samples were analyzed for TPH as diesel (EPA Modified
8015), copper and zinc (EPA 200.7/SW6010), and lead (EPA 239.2/SW7421).
46
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Section 4.0: TREATMENT SYSTEM PERFORMANCE
4.1 Cleanup Goals. The full-scale bioslurper system is being operated in a manner to ensure
that oil/grease and heavy metals in the treated water effluent from the CSS Waste Water Treatment Plant
(WWTP) will not exceed current levels. Water samples from the effluent of the full-scale bioslurper
system are collected monthly and are analyzed for TPH, copper, lead, and zinc. In the event that the
flowrate of water to the WWTP approaches the maximum operating capacity of the WWTP, the vacuum-
enhanced recovery system either will be adjusted to reduce the water flowrate to the WWTP or will be
shut down until the flowrate to the WWTP returns to its normal operating range. Water samples are
collected periodically from the effluent discharged from the WWTP to ensure that the treated water is in
compliance with permitting requirements. This water treatment technology demonstration was
performed to determine the percent removal of TPH, copper, lead, and zinc and the quality of the effluent
water that is economically achievable using the CRF/DAF and Oleofilter™^ water treatment
technologies to treat the water generated by the full-scale bioslurper process.
4.2 Treatment Performance. Water samples were collected from the influent and effluent of
each water treatment process and were analyzed for TPH, lead, copper, zinc, and total suspended solids
(TSS). The analytical results were used to assess the performance of each treatment system. Treatment
performance results are presented in Table 4. The TPH concentrations were measured as both diesel and
motor oil; however, only the TPH as diesel is reported since in most instances the TPH concentration as
motor oil was below the laboratory detection limit. The CRF/DAF system removed greater than 98% of
the TPH compared to the 56 to 90% that was removed by the Oleofilter™. The high concentrations of
TPH in the influent process water likely reduced the separation efficiency of the packing media inside
the Oleofilter™. Previous investigations (US EPA, 1995) have indicated that the operating efficiency
of the Oleofilter™ decreases when the influent concentration of TPH is greater than 500 ppm. The
TPH analytical results are consistent with visual observations made regarding the operation of the
treatment system. The influent water to the processes was a milky yellow color, indicating a high TPH
concentration. The effluent from the CRF/DAF process was clear and had very little if any hydrocarbon
odor associated with it. However, the effluent from the Oleofilter™ was milky, but not as yellow as the
influent water. It had a strong hydrocarbon odor associated with it.
The ability of the CRF/DAF system to remove heavy metals, including copper, lead, and
zinc, was evaluated. The first two sets of samples collected from the CRF/DAF were analyzed for 13
metals including antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel,
selenium, silver, thallium, and zinc. Of these metals, copper, lead, and zinc are the primary contaminants
of concern since concentrations of these metals in the treated water from the CSS WWTP approach
maximum allowable discharge concentrations. Analytical results for the remaining metals were below
laboratory detection limits for both influent and effluent water to the water treatment processes. The
performance results for removal of copper, lead, and zinc are presented in Table 4. In some instances the
concentrations of metals in the influent and/or effluent streams were below laboratory detection limits.
Matrix interferences encountered during the laboratory analyses prevented some of the samples from
being reported at lower detection limits. Therefore, in some cases, it was impossible to accurately assess
the percent removal of a particular metal. The detection limit was used to calculate the percent removal
and the results are expressed with a greater-than sign.
47
-------
Table 4. Water Treatment System Performance Results
b Average Average Range of
Untreated Treated Percent
Concentration Concentration Removal
ent (ppm) (ppm) (%)
-:-:--•-
sel
Copper
Zinc
TSS
•IIIM^ hiHiiiiB^
10,950
442
<101
2,450
308
CRF/PA]
43.8
<56.3
<55
<136
<12.2
* ^^ «J. '" ' UJni J * "
98.2 to 99.9
>67.7 to 98.9
>90.2
>8 1.3 to 97.9
92.1to>98.2
Average
Percent
Removal
'n. x"^>,, , !
99.5
>88.0
>90.2
>91.3
>95.2
§r M mir f r - -" ' " '• "— -«r(>leofiiier*J*l - ' , '* „ . „,.;•-
TPH
Lead
Copper
Zinc
TSS
10,950
442
<101
2,450
308
4,687
55
<100
4,204
237
55.6 to 90.3
12.5 to 75.3
NA
-827 to 73 .3
-12.8 to 58.6
72.6
50.8
NA
0.322
17.2
NA —Not applicable. Copper concentrations were below the detection limit both before and after
treatment, therefore percent removal could not be calculated.
The effluent from the Oleofilter™ also was analyzed for copper, lead, and zinc. Although
the OleofilterTM Was not expected to remove these metals from the process stream, samples were
collected and analyzed for comparison with the CRF/DAF results. The results are presented in Table 4.
The percent removal varies significantly from one sample to the next. The low pH (4.8 to 5.9) of the
water may have been causing the metal cations to be absorbed by the unit and/or packing material.
Eventually, these cations would have desorbed back into the process stream. This would account for the
significant fluctuations observed in the data.
Water samples also were analyzed for TSS. The reduction of TSS after treatment by the
CRF/DAF indicates a good separation of the coagulated/flocced material from the process water. If good
separation and removal were not occurring, the concentration of TSS could potentially be much greater
in the effluent than in the influent water samples.
4.3 Performance Data Assessment. This demonstration has indicated that the CRF/DAF
system is effective at removing significant quantities of emulsified oils and metals from the process
water. Good removal efficiency of metals was achievable by adding sodium hydroxide to increase the
pH to about 9 in the CRF tank and removing the resulting precipitate as part of the oil saturated sludge
that accumulates inside the DAF. The sludge was automatically pumped into a settling tank. It was
periodically dewatered by turning on a sump pump located at the bottom of the tank. The resulting water
was pumped back into the 500-gallon process water surge tank. An average of 20 gallons of dewatered
sludge were accumulated each day of operation. A Toxicity Characteristic Leaching Procedure (TCLP)
analysis was performed on the sludge to determine if it was hazardous. The results, presented in
Appendix A, indicate that the sludge can be disposed of as a nonhazardous waste. In addition, the high
oil/grease content in the sludge allows the sludge to be recycled and blended for heat recovery.
The Oleofilter™ did not perform as well as the CRF/DAF treatment system. The percent
removal of hydrocarbons ranged between 56 and 90%. It is believed that removal would be greater when
the concentration of emulsified hydrocarbons in the influent water to the unit is less. The Oleofilter™
48
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is not designed to remove metals from the treatment stream. If this technology was used for the
remainder of the full-scale remediation, a clarifier would need to be installed downstream of the
Oleofilter ™ to remove metals to levels observed when using the CRF/DAF.
Operation and maintenance requirements for the CRF/DAF are significantly greater than for
the Oleofilter™. The CRF/DAF system is equipped with 3 metering pumps, two mixers, a belt
skimmer, a centrifugal pump, and two pneumatically operated diaphragm pumps. Each piece of
equipment must be maintained and be functioning properly to meet the desired treatment goals. Ferric
sulfate, sodium hydroxide, and polymer are automatically metered into the CRF tank. The operator must
calculate and set the flowrates of the ferric sulfate and polymer metering pumps in order to treat the
process water to the required treatment levels. The dosage of sodium hydroxide is controlled by a pH
controller that uses a general-purpose electrode to measure pH. The pH controller held its calibration
during the 4-week demonstration. It is recommended that the probe be rinsed once a week and that the
controller be calibrated bimonthly. The ferric sulfate and sodium hydroxide solutions are supplied in 55-
gallon drums. The operator must replace the drums periodically. One drum of ferric sulfate lasts
approximately 1 month and a drum of sodium hydroxide lasts about 2 months. The polymer is shipped
in a concentrated form. A 5-gallon bucket should last about 4 months, assuming water flowrates and
contaminant loadings and polymer dosage rate remain consistent with what was observed during the
demonstration. A solution of polymer must be made up every 72 hours. Approximately 1.3 cups of
polymer is added to about 50 gallons of water.
During the 4-week demonstration, a number of operational difficulties with CRF/DAF were
encountered. These problems, and the solutions to them, are presented in Table 5. The majority of the
problems encountered were a result of integrating the CRF/DAF into the bioslurper process. In addition,
the CRF and DAF units used were prototypes developed by Great Lakes Environmental, Inc. for use in
relatively low flowrate applications.
Table 5. Problems and Resulting Solutions Encountered with the CRF/DAF System
Problem
Water does not flow fast enough from the CRF
into the DAF at high process water flowrates,
resulting in fouling of the CRF by sludge that
accumulates in the unit
Water effluent and sludge diaphragm pumps
operate continuously.
Vapor lock occurs in centrifugal recycle pump
after extended periods of shut down
Potential spill hazard from CRF and DAF if
effluent pump shuts off.
Potential splashing of process water from high
winds and rain; potential damage to mixers
from rain.
Solution
First raised CRF by 8 inches. Flowrate still
not fast enough; therefore, replaced 1.5-inch
PVC line with a 2-inch polypropylene hose.
Install timer to periodically turn on sludge
pump. Install level switch inside DAF to turn
on water effluent pump. An auxiliary control
panel had to be installed to operate.
Uncouple effluent line from pump; allow air
to bleed out.
Install high level switches in CRF and DAF to
shut down diaphragm pump that supplies flow
to the water treatment equipment.
Manufactured fabricated covers and supplied
rain shields to protect tanks and mixers
49
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Minimal maintenance is required for the Oleofilter™. The unit consists of two pumps, a
fixed-bed containing ceramic packing, and a number of pneumatically operated solenoid valves. The
manufacturer has indicated that 8% of the packing will need to be replaced annually. During the
demonstration, corrosion in the housing of the centrifugal pump resulted in a leak. The system had to be
shut down until the housing could be repaired. No other mechanical difficulties were encountered during
the 4-week demonstration period.
50
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Section 5.0: TREATMENT SYSTEM COST
The costs for treating the process water using the two water treatment technologies are
standardized according to the format for the interagency work breakdown structure (WBS) (Member
Agencies of the Federal Remediation Technologies Roundtable, 1995b). The interagency WBS specifies
9 before-treatment cost elements, 12 treatment cost elements, and 5 after-treatment cost elements. The
cost breakdown for the CRF/DAF and Oleofiltration™ treatment systems are presented in Table 6.
Travel costs have not been included in this estimate. The before-treatment costs include costs associated
with procuring and installing the equipment. These costs were not broken down according to treatment
process. However, it can be assumed that about half of the preparatory costs were associated with the
procurement and mobilization of each water treatment process.
The treatment costs for each water treatment technology have been calculated. Treatment
costs have been grouped into four categories consisting of setup, startup and evaluation, training, and
operation. The costs for setup, startup and evaluation, and training were estimated based on actual costs
associated with the project. The short-term operating costs (6 months of operation) were estimated based
on data collected during demonstration of the equipment. These costs assume that the treatment
equipment will be leased. The lease rate for the DAF is $4,500 per month and the monthly lease price
for the Oleofilter™ is $2,500. If desired, the CRF/DAF system may be purchased for about $51,000
and the Oleofilter can be purchased for about $12,000.
Operating costs of the CRF/DAF are twice as great as those of the OleofilterTM This is
primarily a result of the greater rental cost associated with the CRF/DAF system. In addition, there is
about twice as much labor associated with maintaining the CRF/DAF system than there is with
maintaining the OleofilterTM. The additional labor results from having to supply and monitor the
treatment chemical dosage rates. Another cost associated with operating the CRF/DAF system is the
disposal cost for the sludge that the process generates (currently about $170/month).
The after-treatment costs include dismantling, demobilization, and reporting costs. The
dismantling and demobilization costs presented in Table 6 are associated with the OleofilterTM. These
estimates are based on actual labor hours and costs that were incurred while removing the OleofilterTM
from the system at the end of the demonstration. These costs do not include costs to remove subsurface
plumbing that was installed from the bioslurper process to the OleofilterTM^ since the plumbing was left
in place at the site for possible future use during the remainder of full-scale bioslurper operation.
51
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Table 6. CRF/DAF and OleofiltrationTM Cost Elements
Cost Element
V • - " • ' " " --v Before Treatment Costs ""
Mobilization and Preparatory Work
Setup
• Rental of DAF
• Installation materials
• Labor
Startup and Evaluation
• Labor
• Analytical
• Materials
• Waste disposal
Training
Operation (short-term operating costs; assumes 6 months
of operation)
• Labor to perform routine O&M activities
• Equipment (rental of CRF/DAF) and materials
• Bulk chemicals
• Waste disposal
• Analytical
lie :? ! ; ass • s txscs. • «^
Setup
• Rental of Oleofilter™
• Installation materials
• Labor
Startup and Evaluation
• Labor
• Analytical
• Materials
• Waste disposal
Training
Operation (short-term operating costs; assumes 6 months
of operation)
Labor to perform routine O&M activities
Equipment and materials
Bulk chemicals
Waste disposal
Analytical
w si"*1 i"i 'tin 1 iki i MII *,i jiii i,ii ™« : AfterriceMffl^it £0lts
Dismantling Oleofilter A M
Demobilizing OleofilteriM
Reporting
Cost ($)
"* , "> "^
$9,120
_ r * * ,-**»-
$18,900
$7,160
$688
$45,400
, i.
$6,260
$7,160
$132
$21,900
-_
$392
$3,577
$8,040
52
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Section 6.0: OBSERVATIONS AND LESSONS LEARNED
Performance observations and lessons learned:
• The CRF/DAF removed a greater percentage of TPH from the process water than did the
Oleofilter™.
• The CRF/DAF system is capable of removing >99.9% TPH as diesel from an influent stream
containing greater than 5,000 ppm TPH as diesel.
• The CRF/DAF system can precipitate and remove a significant concentration of copper, lead, and
zinc. Greater than 90% removal of these metals was observed.
• Greater than 90% removal of TPH by the Oleofilter™ cannot be achieved at high influent water
concentrations.
Cost observations and lessons learned:
• It costs twice as much to operate the CRF/DAF system than to operate the Oleofiltration™ system.
It is estimated that it will cost about $7,580/month to lease and operate the CRF/DAF and about
$3,650/month to lease and operate the Oleofiltration™ system.
• Excluding lease rates, the monthly operating costs for the CRF/DAF and Oleofilter™ are estimated
to be $3,080 and $1,150, respectively.
General:
• Although the CRF/DAF system is more expensive to operate than the Oleofilter™, it has a much
greater percent removal of TPH at high influent concentrations (5,000 to 27,000) ppm than does the
Oleofilter™. In addition, it efficiently removes metals, including copper, lead, and zinc, from the
process water. Therefore, it is believed that the CRF/DAF is the more appropriate technology for
treating the bioslurper process water produced at AOC 1.
• The pH electrode in the CRF stage 2 tank should be rinsed once a week. The pH controller should be
calibrated bimonthly.
• The CRF should be installed about 8 inches higher than the DAF, and a 2-inch-diameter or greater
hose should be used to plumb the CRF effluent port to the DAF influent port. This allows the water
to pass between the units at a greater flowrate.
53
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Section 7.0: REFERENCES
ABB Environmental Services, Inc. 1995. Performance Criteria Package, Free-Product Removal, Area
of Concern 1, Coastal Systems Station Panama City, Panama City, Florida. Prepared for the Naval
Facilities Engineering Command, North Charleston, SC.
ABB Environmental Services, Inc. 1996. Resource Conservation and Recovery Act, Facilities
Investigation, Coastal Systems Station Panama City, Panama City, Florida. Prepared for the Naval
Facilities Engineering Command, North Charleston, SC.
Battelle. 1997. Interim Measures Workplanfor Full-Scale Bioslurper Implementation at Area of
Concern I. Coastal Systems Station, Panama City, Florida. Prepared for the Naval Facilities
Engineering Service Center, Port Hueneme, California.
Member Agencies of the Federal Remediation Technology Roundtable. 1995a. Remediation Case
Studies: Bioremediation.
Member Agencies of the Federal Remediation Technology Roundtable. 1995b. Guide to Documenting
Cost Performance for Remediation Projects.
U.S. Environmental Protection Agency. 1995. InPlant Systems, Inc. SFC 0.5 Oleofiltration System,
Innovative Technology Report.
54
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Pump and Treat and Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Former Intersil, Inc. Site,
Sunnyvale, California
55
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Pump and Treat and Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Former Intersil, Inc. Site,
Sunnyvale, California
Site Name:
Former Intersil, Inc. Site
Location:
Sunnyvale, California
Contaminants:
Chlorinated solvents
- Maximum concentrations
detected in 1986 were TCE (13,000
ug/L), cis-l,2-DCE (19,000 ug/L),
Vinyl chloride (1,800 ug/L), and
Freon-113 (16,000 ug/L)
Period of Operation:
Status: PRB Ongoing
Report covers:
-P&T: 11/87-2/95
-PRB: 2/95-11/97
Cleanup Type:
Full-scale cleanup (interim results)
Vendor:
Construction and Operations:
Scott Warner
Geomatrix Consultants, Inc.
100 Pine St., 10th floor
San Francisco, CA 94111
(415)434-9400
P&T: Reidel Environmental
Services/Delta Cooling Towers
PRB: EnviroMetal
Additional Contacts:
Deborah Hankins, Ph.D.
Intersil, Inc.
114 Sansome St., 14th floor
San Francisco, CA 94104
(415)274-1904
Technology:
Pump and Treat and Permeable
Reactive Barrier
- Groundwater was extracted using
three wells and one trench well at
an average total pumping rate of 8
gpm
- Extracted groundwater was
treated with air stripping and
discharged to an on-site storm
sewer under a NPDES permit
- The permeable reactive barrier
(PRB, treatment wall) is 100%
granular iron, 4 ft thick, 40 ft wide,
and approximately 13 ft deep; 2
slurry walls are used to route
groundwater through the PRB
Cleanup Authority:
State cleanup
- Site cleanup requirements order:
10/15/86
State Point of Contact:
Habte Kifle
CA RWQCB
2101 Webster Street, #500
Oakland, CA 94612
(510)286-0467
Waste Source:
Leakage from sub-grade
neutralization system
Purpose/Significance of
Application:
Used P&T for eight years, and
replaced this technology with PRB;
PRB used for three years.
Type/Quantity of Media Treated:
Groundwater
-38 million gallons treated as of November 1996 (36 million by pump-
and-treat and 2 million by PRB)
- Extraction wells are located in 1 aquifer, to a depth of 18 ft (depth to
groundwater not provided)
- Transmissivity reported as 370 ftVday (hydraulic conductivity not
provided)
Regulatory Requirements/Cleanup Goals:
- The cleanup goal for the site is to reduce contaminant concentrations throughout the aquifer to levels below the
maximum contaminant levels (MCLs) set by the state of California and primary drinking water standards.
- Remedial goals were identified for vinyl chloride (0.5 ug/L), cis-l,2-DCE (6 ug/L), TCE (5 ug/L), and Freon-
113 (1,200 ug/L).
- Effluent from the treatment system was required to meet the remedial goals prior to discharge.
- A secondary goal was identified to create an inward gradient to contain the plume.
- The primary goal for the PRB is to reduce contaminant levels in groundwater passing through the wall to the
cleanup goals for the site.
- The secondary goal for the PRB is to contain the contaminant plume upgradient of the wall.
56
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Pump and Treat and Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Former Intersil, Inc. Site,
Sunnyvale, California (continued)
Results:
- The contaminant plume has been reduced in size at this site, however, contamination remains elevated at three
hot spots.
- Average total contaminant concentrations have decreased from 1,609 ug/L in 1986 to 31 ug/L in 1997.
- By 2/95, the P&T system had removed 56 kg of contaminants from the groundwater; from 2/95 to 8/96, the
PRB had removed 7 kg of contaminants from the groundwater.
- The contaminant plume has been contained.
Cost:
- Estimated costs for the P&T system from 1987 to 1995 were approximately $1,343,800 ($325,000 in capital
and $1,018,800 in O&M), which correspond to $38 per 1,000 gallons of groundwater extracted and $10,900
per pound of contaminant removed.
- Estimated costs for the PRB system through 11/96 were approximately $762,000 ($5955,000 in capital and
$167,000 in O&M), which correspond to $38 per 1,000 gallons of groundwater extracted and $49,400 per
pound of contaminant removed.
Description:
Intersil operated at the site as a semi-conductor manufacturer from the early 1970s until 1983. The site is
currently owned by Sobrato Development Company, and was released to another tenant in 1995. In 1972,
Intersil installed a concrete, epoxy-lined, in-ground acid neutralization system at the facility to neutralize
wastewater before discharge to a sanitary sewer. In 1982, the California Regional Water Quality Control Board
(RWQCB) requested sampling of shallow groundwater and soil near the neutralization holding tank, and Intersil
identified chlorinated solvents in the shallow groundwater and soil. Under a state program, a site cleanup
requirements order was issued in October 1986.
A pump and treat (P&T) system was operated at this site from 1987 until 1995. The system consisted of three
extraction and one trench wells. The wells were installed to a depth of 18 ft and had a design yield of 6 gpm.
Extracted groundwater was treated with an air stripper designed to handle a maximum of 40 gpm.In 1993, Intersil
examined alternative groundwater remediation technologies based on achievement of two goals. Intersil wanted
to minimize the cost of treatment while increasing treatment effectiveness, given that the mass removal by the
P&T system had asymptotically declined, and to return the site to leasable/sellable conditions. The selected
alternative, approved by the RWQCB, was a PRB. The treatment technologies used at this site have removed
contaminant mass and reduced concentrations in the aquifer; however, site cleanup goals have not yet been met.
57
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Former Intersil, Inc. Site
SITE INFORMATION
Identifying Information:
Treatment Application:
Former Intersil, Inc. Site
Sunnyvale, California
CERCLIS #: Not Applicable (NA)
ROD Date: NA, not a CERCLA Site
Site Cleanup Requirements Order:
October 15,1986
Type of Action: State cleanup
Period of operation:
Pump and treat (P&T) system: 11/87 - 2/95
Permeable Reactive Barrier: 2/95 - Ongoing
(Data on performance collected through
November 1997)
(Cost data and data on mass removal collected
through November 1996)
Quantity of material treated during
application: 38 million gallons of groundwater
(36 million gallons through a P&T system)
(2 million gallons through treatment wall as of
November 1996)
Raekaround
Historical Activity that Generated
Contamination at the Site: Semiconductor
manufacturing
Corresponding SIC Code: 3674
(Semiconductors and Related Devices)
Waste Management Practice That
Contributed to Contamination: Leakage from
sufagrade neutralization system
Location: Sunnyvale, California
Facility Operations: [2,3]
• Intersil operated at the site as a semi-
conductor manufacturer from the early
1970s until 1983. In 1983, the facility shut
down and was used to warehouse office
equipment and surplus supplies. The site is
currently owned by Sobrato Development
Company. The site was released to another
tenant in 1995.
• In 1972, Intersil installed a concrete, epoxy-
Hned, in-ground acid neutralization system
at the facility to neutralize wastewater
before discharge to a sanitary sewer.
In 1982, the California Regional Water
Quality Control Board (RWQCB) requested
shallow groundwater and soil sampling near
the neutralization holding tank.
Investigations performed on behalf of
Intersil identified halogenated volatile
organic compounds (VOCs) as the main
contaminant in the shallow groundwater
beneath the site. In 1985, at the request of
the RWQCB, further investigations were
performed at the site. Intersil found
halogenated VOC contamination in the soil
beneath the site. Further soil and
groundwater investigations performed in
1986 indicated a potential contaminant
source was in the area of the neutralization
holding tank. An unknown amount of
contaminants was released to the soil and
groundwater.
In January 1987, Intersil inactivated the
neutralization holding tank and removed it
along with the associated contaminated soil.
Further investigation of the soil and
groundwater beneath the site was
performed by Geomatrix on behalf of Intersil
in 1987 and 1988, including the installation
of an extraction well in the former tank area.
Groundwater surveys were also performed
by Western Microwave, Inc. (WM), at the
property east of Intersil. These surveys
identified VOC contamination at the WM
facility. Groundwater extraction and
treatment through an air stripper began at
the Intersil site in November 1987 as an
interim corrective action.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
58
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Former Intersil, Inc. Site
!SITE INFORMATION (CONTINUED)
Background (Cont.)
• The extraction system was expanded in
1989 and again in 1991.
• An alternative remedy, a permeable
reactive barrier (PRB), was installed and
completed in February 1995 to replace the
P&T system. PRBs are also referred to as
in situ treatment walls for the purposes of
this report.
Regulatory Context:
• Site activities are regulated by the RWQCB.
Site activities during operation of the P&T
system were conducted under provisions of
two Waste Discharge
Site Logistics/Contacts
Requirements (WDR) Orders for the site: Site
Cleanup Requirements (SCR) Order dated
October 15,1986 for groundwater cleanup and
a NPDES permit issued August 19, 1987. The
initial NPDES Permit was replaced by General
NPDES Permit No. 94-087 dated July 20, 1994.
Remedy Selection: Following seven years of a
P&T application, a PRB, or in situ treatment
wall, was selected as a final remedy for
groundwater remediation because of its lower
maintenance requirements, and because it
allowed Intersil to transfer the lease [2].
Site Lead: PRP
Oversight: State
State Contact:
Habte Kifle*
RWQCB
2101 Webster Street, #500
Oakland, California 94612
510-286-0467
Scott Warner
Geomatrix
100 Pine St., 10th Fl.
San Francisco, CA 94111
415-434-9400
indicates primary contact
Treatment System Vendor:
Construction Prime: Geomatrix Consultants,
Inc.
General Contractor: Inquip
Treatment Technology: EnviroMetal (Treatment
Wall)
Treatment Technology (Pump and Treat)
Reidel Environmental Services/Delta Cooling
Towers
Operations Contractor: Geomatrix Consultants,
Inc.
PRP:
Deborah Hankins, Ph.D.
Intersil, Inc.
114SansomeSt., 14th Fl.
San Francisco, CA 94104
415-274-1904
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the
Treatment System: Groundwater
Contaminant Characterization M. 21
Primary Contaminant Groups: Halogenated
volatile organic compounds (VOCs)
EPA
The contaminants of concern at the site are
trichlorethene (TCE), c/s-1,2-dichloroethene
(c/s-1,2-DCE), vinyl chloride (VC), and
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
59
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Former Intersil, Inc. Site
MATRIX DESCRIPTION (CONTINUED)
Characterization fConU
Freon-113. The maximum concentrations
initially detected at the site during the 1986
shallow groundwater survey were TCE at
13,000 ug/L, c/s-1,2-DCE at 19,000 ug/L,
VC at 1,800 ug/L, and Freon-113 at 16,000
ug/L. Contamination has only been
detected in the upper aquifer (A-zone).
The source of the contamination is the
former in-ground neutralization system,
located east of the on-site building.
However, groundwater survey data from
wells installed at adjacent facilities reveal
that the adjacent property, WM, has
released tetrachloroethene (PCE) and other
chemicals to the soil and groundwater.
Intersil is cross- and down-gradient of WM.
Geomatrix, the PRP's contractor, found that
the distribution of VOC contamination at the
Intersil facility did not
change significantly from 1986 to 1993.
However, documents maintained at the
RWQCB show that VOC concentrations
increased at the WM facility from 1986 to
1993.
Figure 1 depicts the concentration contours
of TCE detected during the 1986 shallow
groundwater survey by Geomatrix in the A-
zone (upper aquifer) at the Intersil site. The
plume hot spots are north and northwest of
the suspected source.
Based on the 1986 contour map shown in
Figure 1, an average aquifer thickness of
four feet, and a porosity of 0.30, the initial
contaminant plume was estimated for this
report to be approximately 2.4 acres in
surface area with a volume of
approximately 933,730 gallons. No
additional information on the size of the
initial plume was available in references.
ix Characteristics Affecting Treatment Costs or Performance
Hydrogeology: [1,2]
Two distinct hydrogeological units have been identified beneath this site.
Unit 1 A-zone The A-zone unit is a semiconfined aquifer that ranges in thickness from
eight feet to less than one foot, with a general thickness in the area of
the site of two to four feet. It is composed of interfingering zones of silty
fine-grained sand, fine- to medium-grained sand, and gravelly sand. The
geometry of the aquifer is irregular, with a local presence of clay lenses.
The A-zone unit is mostly confined by an upper silty-clay and clay layer
ranging from nine to 12 feet thick in the area of the site and by a lower
aquitard of clay and silty clay, which is approximately 65 feet thick in the
vicinity of the site. The A-zone aquifer is generally not usable for
consumption due to a high level of total dissolved solids. Groundwater
flow is northerly.
Unit 2 B-zone The B-zone has not been fully penetrated by soil borings, and no
contamination has been detected in this zone. It is separated from the
A-zone by the 65-foot thick aquitard of clay and silty clay. Based on
characteristics of the aquitard, and an upward vertical hydraulic gradient
contaminated groundwater from the A-zone is not expected to migrate to
the B-zone.
Tables 1 and 2 present technical aquifer information and technical well data, respectively.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
60
TIO3.WP6\0216-03.Stf
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Former Intersil, Inc. Site
MATRIX [DESCRIPTION (CONTINUED)
REAMWOOD AVENUE
-"• \\ -\
•*' \\ ,®j
HMMF.RMOOD AVENUE
• HO
NO
In parts
Ippbl. Dashes Indicate lest
certain extent of plume
100 Feet
I
Figure 1. Estimated Distribution of TCE in the A-zone Aquifer Detected During 1986 Shallow
Groundwater Survey (Best Copy Available) [1]. (The former neutralization system was located south of
monitoring well 1A, along the eastern edge of the on-site building)
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
61
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Former Intersil, Inc. Site
MATRIX DESCRIPTION (CONTINUED)
Matrix Characteristics Affecting Treatment Costs or Performance fConU
Unit Name
A-zone
B-ZOH6
Thickness
(ft)
1-8 feet
Not ChsirsctBrizGd
Transmissivity
(ftVday)
370.0
Not Characterized
Average Flow
Rate (ft/day)
0.8
Not Characterized
Flow Direction
Northwest to
Northeast
Not Characterized
Source: [1]
TREATMENT SYSTEM DESCRIPTION
Pump and treat with air stripping (1987 until
1995); Permeable Reactive Barrier (PRB)
(1995 to present)
§ysj§m Description and Operation [2.9.12.15.161
Supplemental Treatment Technology
Liquid-phase carbon adsorption (1987 until
1995, associated with the P&T system)
Table 2. Technical Well Data
Well Name
E7A
E14A
E15A
E18A
Unit Name
A-zone
A-zone
A-zone
A-zone
Depth (ft)
18
18
18
18
Design Yield
(gpm)
6
6
6
6
Source: [1,4-12,13]
System Description
• The original extraction system operated
from 1987 until 1995. The system, initially
one extraction trench well, was expanded to
include three extraction wells; the system
was then expanded to three extraction and
one trench wells. The treatment system
consisted of an air stripper. In addition, two
carbon adsorption units were installed as
backup if needed; however, these units
were never used. Treated water was
discharged to an on-site storm sewer under
an NPDES permit. The stripper tower was
three feet in diameter and designed to
handle a maximum flow of 40 gpm. Treated
water was discharged to a storm sewer.
The PRB, or in situ treatment wall system,
completed in 1995, consists of a granular
iron treatment zone and hydraulic barrier
system. The components are two slurry
walls, permeability zones upgradient and
downgradient of the treatment wall, and the
treatment wall. Technical wall design data,
including design transmissivity, are listed in
Table 3. Figure 2 illustrates the plan view of
the treatment wall system located at the
northeast corner of the property,
downgradient of the suspected on-site
source area.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
62
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Former fntersif, fnc. Site
TREATMENT! SYSTEM DESCRIPTION (CONT.)
P«rmsabie subsOdaeo
treatment wall
[
I»A|Q|
20A EH025A
21 A IH
22AB 01 A
rfi *
•
i
N -*-
Solo
slurry
f
OOA
/
Monitoring
Well
_-.___«._.| ^^^
I
I
I
NOT TO SCALE
BiTHirtt-b«ntoftH*
wall
•^^^HH^B
Ofoondwatar flow
^^s^
\
Camom-bonionUe
slurry wall
Figure 2. Plan View of the Treatment and Slurry Wall System (Best Copy Available) [16]
Hydraulic B»rrtoT"
M
Str««mlin«
NOT TO SCALE
Figure 3. Example of Groundwater Flow Modeling of the Treatment and Slurry Wall System
(Best Copy Available) [16]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
63
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Former Intersil, Inc. Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
System DescrJgtion and Operation (Cont.l
Table 3. Technical Wall Data - Design Parameters
Unit
Flow Control Zone
Treatment Wall
Flow Control Zone
'Approximate values
Flow-Through
Thickness
2 feet
4 feet
2 feet
Transmissivity1
(ftVday)
10,000
1,400
10,000
Material
Pea Gravel
Granular Iron
Pea Gravel
Vertical
Thickness
13 feet
13 feet
13 feet
used for model development
Source: [4]
• The two slurry walls, 300 feet long on one
side of the treatment wall and 235 feet long
on the other side, route groundwater through
the treatment wall. Groundwater flow
through the treatment and slurry wall system
was modeled by Geomatrix. Figure 3
illustrates how groundwater flows north-
northwest through the funnel and through
the treatment wall. Modeling also was
performed for groundwater flow to the north
and northeast.
• Two permeable zones are used upgradient
and downgradient of the treatment zone to
provide uniform velocity. The permeable
zones, called flow control zones, are
composed of high permeability pea gravel.
The zones are two feet thick, and are the
same height and width as the treatment
wall.
• The treatment zone of the wall is composed
of 100% granular iron which degrades the
chlorinated VOCs into end products of
chloride and ethylene through reductive
dechlorination. The zone is 4 feet thick,
approximately 40 feet wide, and
approximately 13 feet high.
• During the P&T system operation,
groundwater quality was monitored through
a network of 17 wells: 13 monitoring wells
and up to four extraction wells. Water table
levels were monitored through the wells and
three piezometers.
• During the operation of the current
treatment wall, the groundwater quality has
been monitored through a network of 13
wells. Six monitoring wells were installed
within the treatment wall; one additional was
installed just upgradient of the treatment
wall to measure its performance. The other
seven monitoring wells are the same
monitoring wells used during the P&T
system operation. Water table levels are
monitored through a network of 14
piezometers in addition to the 13 monitoring
wells.
System Operation
• Quantity of groundwater treated:
Average Volume
Year Pumped (gal/day) Treatment System
1987-1992 25,000,000' P&T
1993-1994 10,659,4651 P&T
1995-1997 2,361,7762 Treatment Wall
1Based on actual pumping rate through the treatment system
Calculated for this report, based on average groundwater
velocity of 0.94 ft/day through treatment wall (in Final Design
Report [4]) and dimensions of 40 feet wide and 13 feet high
[6].
• The in situ treatment wall is operational
100% of the time. The P&T system was
operational approximately 98% of the time.
• The extraction system was modified over
the life of the P&T system from one trench
well to three extraction wells and a trench
well. Details on extraction well construction
and use are specified in Table 5, Timeline.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
64
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Former Intersil, Inc. Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation fConU
In 1993, Intersil examined alternative
groundwater remediation technologies to
evaluate cost-effective alternatives. One
goal was to minimize the cost of treatment
while increasing the treatment
effectiveness, given that the mass removal
by the P&T system had asymptotically
declined. Another goal was to return the
site to leasable/sellable conditions.
According to Intersil, as long as the P&T
system was operating at the site, the
company would have to continue to lease
the site to provide for power and space for
the system.
The selected alternative approved by the
RWQCB was an in situ granular iron
treatment wall system, followed by
shutdown and removal of the P&T system.
Construction of the iron treatment wall was
completed and the P&T system was shut
down in February 1995.
Groundwater is routed to the treatment wall
by the two slurry walls which are keyed into
the confining clay layer. The treatment wall
is keyed into the slurry walls on the eastern
and western ends and into the confining
lower layer at the bottom. Groundwater flow
varies from the northwest to the north on
site. The low permeability slurry walls help
provide uniform flow direction and velocity
through the wall. In addition, the flow ,
control zones provide uniform velocity.
Pilot-scale studies and canister studies were
performed by EnviroMetal, Inc., the
treatment wall vendor, and Geomatrix to
determine the required residence time to
fully degrade the halogenated VOCs. VC
was determined to take the longest time to
degrade, with a required residence time of
approximately two days in the wall, to
reduce site concentrations to cleanup
standards. Therefore, the full-scale iron
treatment wall was designed based on a 4-
foot flow through thickness and a maximum
velocity of 1.2 feet per day, to provide a
groundwater residence time greater than the
required two days.
In August 1995, the eastern slurry wall was
determined by Geomatrix to be leaking.
The cause of the leak was believed by
Geomatrix to be damage from construction
by others at the eastern adjacent WM
facility and from pumping at the WM P&T
system. The slurry wall was repaired in
December 1995 by injecting grout into the
ground adjacent to the wall. Eleven
piezometers were added to monitor the
effect of the WM extraction system,
resulting in the current total network of 14
piezometers. Monitoring data since
December 1995 indicate the slurry wall has
been functioning properly.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
65
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TREATMENT SYSTEM DESCRIPTION (CONT.)
Ooeratlna Parameters Affecting Treatment Cost or Performance
The major operating parameters affecting cost or performance for the treatment wall and the P&T
system are residence time and extraction rate, respectively. Table 4 presents the values measured for
each.
Table 4. Performance Parameters
|, ' , , Parameter . . .' , ','."''.'"."."''?
Actual Average Extraction Rate (P&T)
Average Flow Rate through Treatment Wall
Minimum Required Residence Time (Treatment Wall)
Approximate Residence Time
Performance Standards for P&T NPDES Requirements
(Effluent)
Performance Standard for Treatment Wail
California and EPA Maximum Contaminant Levels
(MCL)
Remedial Goal for P&T, in ug/L (aquifer)
Remedial Goal for Treatment wall, in ug/L
' ' "" W-',y.-^;:.fe« . Value v;u '•<
8 gpm
2.5 gpm
2 days
At least 3 days
TCE: 5.0 ug/L
c/s-1,2-DCE: 5.0 ug/L
VC: 0.5 ug/L
Freon-113: 5.0 (jg/L
TCE: 5.0|jg/L
c/s-1,2-DCE: 6.0 \ig/L
VC: 0.5(jg/L
Freon-113: 1,200 ug/L
California and EPA MCLs
(same as Performance Standard for Treatment Wall)
California and EPA MCLs
(same as Performance Standard for Treatment Wall)
Source: [1,2]
Timeline
Table 5 presents a timeline for this remedial project.
Table 5. Project Timeline
!!!f,:itii'''D«te
10/15/86
01/87
11/87
11/89
12/91
02/92
11/94
02/95
8/95
1/96
End Date
—
—
_
—
—
12/92
—
—
12/95
_
• • :" • i "" Activity " ,/' •',.
Site Cleanup Requirements (SCR) order issued
Inactive in-ground neutralization system and approximately 50 yd3 of surrounding contaminated soil
excavated under the direction of the RWQCB, first extraction well installed, monitoring of
groundwater begun
Approximately 108 yd3 of contaminated soil excavated from northeast corner of site, extraction of
groundwater and treatment through air stripper begun as RWQCB approved interim measure
Groundwater extraction system expanded to three wells, and 1 1 monitoring wells installed
Fourth, temporary extraction well installed
Groundwater extracted through temporary extraction well
Installation of treatment wall initiated
Treatment wall installation completed, P&T system shut down
Low water levels observed near eastern slurry wall, 1 1 piezometer network installed and eastern
slurry wall
Slum/wall repaired
Source: [1,2,6,15]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
66
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Former Intersil, Inc. Site
TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards
The cleanup goal for the site is to reduce
concentrations of TCE, c/s-1,2-DCE, VC, and
Freon-113 to levels below the MCL set by the
State of California and Primary Drinking Water
Standards. The required cleanup levels are
listed above in Table 4 and are applied
throughout the aquifer, as measured in all on-
site monitoring wells [1].
Treatment Performance Goals
The primary goal of the treatment system
was to reduce contaminant levels in the
effluent to meet NPDES requirements,
listed above in Table 4 [1].
The secondary goal of the P&T system was
to contain the contaminant plume by
creating an inward hydraulic gradient [1].
Performance Data Assessment T4-161
The primary goal of the treatment wall is to
reduce contaminant levels in groundwater
passing through the wall to the cleanup
goals discussed in Table 4 [15].
The secondary goal of the treatment wall is
to contain the contaminant plume
upgradient of the treatment wall system by
using two slurry walls to route the plume
through the treatment wall [15].
For this report, total contaminant concentration
includes the sum of the concentrations of TCE,
cis-1,2-DCE, VC, and Freon-113. Performance
is described in terms of the overall progress
towards the cleanup goals, based on both the
P&T and treatment wall systems, then in terms
of each system.
Overall Progress
• The contaminant plume size has been
reduced. However, contamination remains
elevated at three hotspots: upgradient of the
treatment wall (wells 1A and 25A), south of
the treatment wall (well 9A), and northeast
of the former Intersil property (well 10A).
Figure 4 illustrates the temporal change in
average total contaminant concentrations
detected during monitoring. Average total
contaminant concentrations have decreased
from 1,609 ug/L in 1986 to 31 ug/L in 1997,
a reduction of 98%.
The average concentration of total
contaminants in the aquifer after seven
years and two months of P&T system
operation was 312 ug/L. The average
concentration of total contaminants
downgradient of the wall after one year and
eight months of treatment wall system
operation was 39 ug/L. In addition, the
contaminant plume has been contained.
Figure 5 presents the removal of
contaminants from the groundwater treated
in the P&T system annually from 1987 until
1995 and through the treatment wall system
from 1995 until August 1996. By February
1995, the P&T system had removed
approximately 56 kg of total contaminant
mass from the groundwater. From February
1995 until August 1996, the treatment wall
system had removed 7 kg of total
contaminant mass from the groundwater.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
67
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Former Intersil, Inc. Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment (Cont.)
P&T System
• Figure 5 shows the P&T system achieved a
maximum rate of total contaminant removal
of close to 0.05 kg/day when operations first
began in December 1987. In December
1990, the P&T total contaminant removal
rate was at its lowest (0.01 kg/day).
Overall, the total contaminant removal rate
during P&T operation declined exponentially
from the initial P&T startup.
During the P&T system operation, the
contaminant concentrations in the effluent
were below standards set by the NPDES
permit in Table 4.
• During the P&T system operation, the
extraction system was determined by site
operators to have created an inward
hydraulic gradient. In doing so, the P&T
system assisted in containing the plume.
Treatment Wall
• During the treatment wall system operation,
the concentrations of TCE and Freon-113 in
monitoring wells downgradient of the
treatment wall were all below cleanup goals
during quarterly sampling events from
PerformanceJJataJCompleteness [3.4-141
March 1995 to November 1996. Levels of
c/s-1,2-DCE and VC have been detected at
up to 26 ug/L and 2.1 ug/L, respectively
(compared to cleanup goals of 6.0 ug/L and
0.5 ug/L, respectively) near the WM
property line.
A P&T remediation system was installed on
the WM site in May 1995. The zone of
capture for that system was determined not
to have affected the treatment wall. Since
the treatment wall was installed,
contaminant levels in wells downgradient of
the wall have not increased, indicating that
the plume has been contained.
During 1995, the eastern slurry wall of the
treatment wall system leaked from being
damaged, but subsequent repairs worked to
seal the leak.
According to the state contact, although
some levels downgradient of the wall are
above cleanup levels, natural attenuation is
occurring, and contaminants are not
migrating further.
Data for the P&T system were available for
December 1987 until February 1995. Data
for the treatment wall system were available
for March 1995 until November 1997.
Concentrations of contaminants in the
groundwater have been monitored quarterly
since January 1987. Previously, from
February 1985 until January 1987,
concentrations of contaminants in the
influent and effluent were monitored weekly.
These data are available from the site
contact in the Self Monitoring and Technical
Status Reports and the NPDES Self
Monitoring Quarterly Reports. For the
analyses in this report, annual data were
used.
Data from all monitoring wells within the
original contaminant plume identified in
Figure 1 were used to calculate the
mean concentration for both P&T and
treatment wall systems. This includes
wells upgradient of the wall. When
concentrations were below detection
limits, half of the detection limit was
used for evaluation purposes.
The contaminant mass removal rate by
the P&T system shown in Figure 5 was
determined for this report using
analytical results from the treatment
plant influent and effluent, along with
well extraction flow rate data. The
contaminant mass removal rate by the
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
68
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Former Intersil, Inc. Site
TREATMENT^ SYSTEM PERFORMANCE (CONT.)
Performance Data Completeness (Cont.)
treatment wall system shown in Figure 5
was determined for this report using an
estimated average linear velocity of 0.94
ft/day, dimensions of the wall, and the
contaminant concentration gradient
observed across the wall from February
1995 to November 1996.
For Figure 4, a geometric mean was used
for average groundwater concentrations
detected in monitoring wells to show the
trend across the entire plume. Annual data
from 11 wells were used for the P&T
system, and data from nine wells were used
for the treatment wall system.
Performance Data Quality
The QA/QC program used throughout the remedial action met the EPA and the State of California
requirements. All monitoring was performed using EPA-approved methods SW-846 Methods 601, 602,
624, 625, Hardness, and TDS. The vendor did not note any exceptions to the QA/QC protocols [4-13].
1
i
U
U
1,800
1,600
1,400
1,200
1,000
800
600
400
200
Figure 4. Total Contaminant Concentrations in the Groundwater(1987-1996) [4-13,16]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
69
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Former Intersil, Inc. Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
0.000
Dec-87 Dec-88 Dec-89 Dec-90 Dec-91 Dec-92 Dec-93 Dec-94 Dec-95 Dec-96
• Mass Flux
-Cumulative Mass Removed
Figure 5. Total Contaminant Mass Flux and Mass Removed as a Function of Time (1987-1996) [4-13,16]
TREATMENT SYSTEM COST
Procurement Process
Intersil contracted with Geomatrix to construct and manage the on-site remediation systems. Intersil
contracted with EnviroMetal, Inc. to contribute to design of the in situ treatment wall.
Cost AnjJyjSjS—
• All costs for investigation, design, construction and operation of the treatment system at this site
were borne by Intersil.
CaDitalCosts (Estimated)
P&T Remedial Construction [1,3]
1987 System Costs
Extraction Well and Treatment $250,000
System
1990 System Costs
Extraction Wells $75,000
Total P&T Site Cost $325,000
Treatment Wall Construction (1995V [2,21]
Slurry Walls $178,000
Treatment Wall $100,000
Transport/Disposal of Soil $45,000
Treatment/Disposal of Water $5,000
(dewatering)
Site Restoration $55,000
Demolition $10,000
New Wells $18,000
Permitting and Initial Sampling $30,000
Bid and Scope Contingencies $154,000
Total Cost Treatment Wall $595,000
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
70
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Former Intersil, Inc. Site
TREATMENT SYSTEM Cost (CONT.)
Ooeratina Costs (Estimated)
P&T System m
Plant Operation & Maintenance $525,600
Costs (1987-1995)
Annual NPDES Monitoring $349,200
Costs
Annual Groundwater $144,000
Monitoring Costs
Cumulative P&T Operating $1,018,800
Costs 12/87 - 2/95
Treatment Wall System [2, 21 ]
Cumulative Treatment Wall
Operating Costs 2/95 -11/96
Other Costs (Estimated)
Construction Oversight
(Treatment Wall)
Engineering Design Costs
$167,000
$75,000
$100,000
Cost Data Oualitv
The cost figures provided were based on estimates by Geomatrix, not actual vendor costs, which
were not available for this site.
The Geomatrix site contact reported that the cost estimate for the treatment wall system, including
subsequent repairs, is within 10% of the actual costs incurred [17].
OBSERVATIONS AND! LESSONS LEARNED
Estimated costs for the P&T system at
Intersil for the period from 1987 to 1995
were approximately $1,343,800 ($325,000
in capital construction costs and $1,018,800
in total operation and maintenance costs),
corresponding to $10,900 per pound of total
contaminants removed and $38 per 1,000
gallons of groundwater treated.
Estimated costs for the treatment wall
through November 1996 are approximately
$762,000 ($595,000 in capital costs and
$167,000 in total operation and
maintenance costs) for the period from 1995
to 1996, corresponding to $38 per 1,000
gallons of groundwater treated and
$108,900 per kg ($49,400/pound) of total
contaminants removed.
By using the passive, in situ treatment wall
system, Intersil did not have to continue to
lease the Sunnyvale property [17]. While
this resulted in less cost to Intersil,
information on specific cost savings was not
provided.
The P&T system removed 56 kg of
contaminants from the groundwater over
seven years; the treatment wall removed 7
kg over two years. However, cleanup goals
have not yet been achieved.
For the treatment wall to be effective, the
entire contaminant plume upgradient of the
wall must be routed through the wall. At the
Intersil site, the plume was captured by the
slurry walls and routed to the treatment wall
[13,15]. For sites at which groundwater flow
direction varies greatly, plume capture can
be more difficult.
If a subsurface source is present, the plume
upgradient of the wall may persist, and
cleanup goals rhay not be achieved.
However, the overall goal to eliminate risk
to human health and environment is
immediately achieved downgradient of the
wall. The advantage of the treatment wall
over the P&T system is the ability to
passively contain and treat the
contaminated plume [20].
The site hydrogeology enabled the
treatment wall to be keyed into a bottom
confining layer [15]. At sites where the
contaminated aquifer is not fully confined on
the bottom, vertical containment of the
plume can be an issue [18].
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
71
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Former Intersil, Inc. Site
REFERENCES
1. Final Remedial Action Plan. Geomatrix
Consultants, May 30,1989.
2. Draft Revised Final Remedial Action Plan.'
Volumes I and II, Geomatrix Consultants,
Inc., January 1993.
3. Correspondence with Dr. Deborah Hankins,
PhD, Intersil, April 30,1997.
4. Self Monitoring and Technical Status Report
Combined Annual Summary. Calendar
Quarter October - December 1993.
Geomatrix Consultants, Inc., January 31,
1994.
5. Self Monitoring and Technical Status Report
Combined Annual Summary. Calendar
Quarter October - December 1994.
Geomatrix Consultants, Inc., January 31,
1995.
6. Self Monitoring and Technical Status
Report. Calendar Quarter January - March
1995. Geomatrix Consultants, Inc., April 27,
1995.
7. Self Monitoring and Technical Status
Report. Calendar Quarter April - June 1995.
Geomatrix Consultants, Inc., July 31,1995.
8. Self Monitoring and Technical Status
Report. Calendar Quarter July - September
1995. Geomatrix Consultants, Inc., October
26, 1995.
9. Self Monitoring and Technical Status Report
Combined Annual Summary. Calendar
Quarter October - December 1995.
Geomatrix Consultants, Inc., January 31,
1996.
10. Self Monitoring and Technical Status
Report. Calendar Quarter January - March.
1996. Geomatrix Consultants, Inc., April 30,
1996.
11. Self Monitoring and Technical Status
Report. Calendar Quarter April - June 1996.
Geomatrix Consultants, Inc., July 31,1996.
12. Self Monitoring and Technical Status
Report. Calendar Quarter July - September
1996. Geomatrix Consultants, Inc., October
31, 1996.
13. Self Monitoring and Technical Status Report
Combined Annual Summary. Calendar
Quarter October - December. 1996.
Geomatrix Consultants, Inc., January 31,
1997.
14. Self Monitoring and Technical Status Report
Combined Annual Summary and Calendar
Quarter October-December 1993.
Geomatrix Consultants, Inc., January 1994.
15. Final Design Report. In Situ Groundwater
Treatment Wall and Slurry Wall. Geomatrix
Consultants, Inc., November 15, 1993.
16. Installation of a Subsurface Groundwater
Treatment Wall Composed of Granular
Zero-valent Iron. Yamane, C.L. et. al.,
presented at American Chemical Society,
April 2-7, 1995.
17. Correspondence with Carol Yamane,
Geomatrix, April 8, April 29, and May 14,
1997.
18. Assessment of Barrier Containment
Technologies. Rumer, Ralph R. and James
Mitchell. U.S. Department of Energy, U.S.
EPA, and DuPont Company. August 29-31,
1995.
19. Groundwater Regions of the United States.
Heath, Ralph. U.S. Geological Survey.
Water Supply Paper 2242. 1984.
20. Final Remedial Action Plan Addendum.
Geomatrix Consultants, Inc., September 28,
1990.
21. Correspondence with Scott Warner,
Geomatrix, June 30 and July 6, 1998.
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
72
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the French Ltd. Superfund Site,
Crosby, Texas
73
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the French Ltd. Superfund Site,
Crosby, Texas
Site Name:
French Ltd. Superfund Site
Location:
Crosby, Texas
Contaminants:
Chlorinated solvents and
Volatiles - nonhalogenated
- Contaminants of concern in the
groundwater were benzene,
toluene, chloroform, 1,2-DCA, and
vinyl chloride
- Initial maximum concentrations
were benzene (19,000 ug/L), 1,2-
DCA (920,000 ug/L), and vinyl
chloride (8,200 ug/L)
Period of Operation:
Status: Ongoing
Report covers: January 1992
through December 1995
Cleanup Type:
Full-scale cleanup (interim results)
Vendor:
Prime Contractor:
Jon McLeod
CH2M Hill
(512)346-2001
Treatment System Vendor:
Mike Day, President
Applied Hydrology Associates, Inc.
Denver, CO
State Point of Contact:
Emmanuel Ndame
TNRCC
(512)239-2444
PRP: Richard Sloan
ARCO Chemical Company
FLTG Project Coordinator
15010 FM 2100, Ste. 200
Crosby, TX 77532
(713)328-3541
Technology:
Pump and Treat with activated
sludge for extracted groundwater;
in situ bioremediation for
contaminated groundwater
- Active remediation conducted
from January 1992 through
December 1995 consisted of
extraction and above-ground
treatment, enhanced aquifer
flushing through pressure injection
of clean water, and accelerated in
situ bioremediation through the
addition of oxygen, phosphorus,
and nitrate.
- Source control was achieved by
installation of cutoff (sheet-pile)
walls around lagoon and DNAPL
source areas.
- Since December 1995, active
pumping was stopped and natural
attenuation has been used to reduce
remaining concentrations of
contaminants. Limited pumping
began in March 1998.
Cleanup Authority:
CERCLA Remedial
- ROD Date: 3/24/88
EPA Point of Contact:
Ernest Franke, RPM
U.S. EPA Region 6
1445 Ross Avenue
Dallas, TX 75202-2733
(214)665-6739
Waste Source:
Unlined disposal pit (lagoon)
Purpose/Significance of
Application:
Regulatory requirements for this
site based on use of modeling
results to show effects of natural
attenuation at the site boundary 10
years after pump and treat
completed.
Type/Quantity of Media Treated:
Groundwater
- 306 million gallons of groundwater and surface treated as of December
1995
- Groundwater is found at 10-12 ft bgs
- Extraction wells are located in two aquifers
- Hydraulic conductivity ranges from 0.283 to 2.835 ft/day
74
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the French Ltd. Superfund Site,
Crosby, Texas (continued)
Regulatory Requirements/Cleanup Goals:
- According to the 1988 ROD, "groundwater recovery and treatment will continue until modeling shows that a
reduction in the concentration of volatile organics to a level which attains the lO'6 human health criteria at the
site boundary can be achieved through natural attenuation in 10 years or less." In response, remedial goals
were established for vinyl chloride (2 ug/L), benzene (5 ug/L), toluene (1,000 ug/L), 1,2-DCA (100 ug/L) and
chloroform (100 ug/L).
- A primary goal of the remedial system was plume containment, accompanied by in situ bioremediation and
source control using sheet-pile walls.
Results:
- A modeling study conducted in late 1995 demonstrated that natural attenuation would reduce groundwater
contaminant concentrations below the remedial goals at the site boundary within 10 years after system shut-off.
As a result, EPA allowed the groundwater recovery and treatment operations to be shut down in December
1995.
- Average concentrations of 1,2-DCA, vinyl chloride, and benzene had been reduced to approximately 1 ug/L in
the twp aquifers at the site by October 1995. As of December 1995, the pump and treat system had removed
517,000 pounds of contaminants (measured as TOC) from the groundwater. No data were available to
quantify the amount of contaminants destroyed through bioremediation.
Cost:
- Actual costs for pump and treat and in situ bioremediation were $33,689,000 ($15,487,000 in capital and
$18,202,000 in O&M), which correspond to $110 per 1,000 gallons of groundwater extracted and $15 per
pound of contaminant removed. The unit cost does not account for the amount of contaminants destroyed
through bioremediation.
Description:
The French Limited site was used for sand mining in the 1960s and 1970s. During the period from 1966 through
1971, the site was permitted to accept industrial waste material for disposal in a seven-acre lagoon created from
an open sand pit. About 80 million gallons of waste material was disposed of in the main waste lagoon. The
facility's permit was revoked and the site was closed in 1973. The site was placed on the NPL in 1981, and a
remedial investigation was performed at the site from 1983 to 1986 through a cooperative agreement. 'A ROD
was signed in May 1987, and amended in March 1988.
Active remediation was conducted at the site from January 1992 through December 1995 by groundwater
extraction and above-ground treatment, enhanced aquifer flushing through pressure injection of clean water, and
accelerated in situ bioremediation through the addition of oxygen, phosphorus, and nitrate. Source control was
achieved by installation of sheet-pile walls around lagoon and DNAPL source areas. As of December 1995,
active pumping was stopped and natural attenuation has been used to reduce remaining concentrations of
contaminants.. Limited pumping began in March 1998.
75
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French Limited Superfund Site
SITE INFORMATION
Identifying information:
French Limited Superfund Site
Crosby, TX
CERCLIS#: TXD980514814
ROD Date: March 24,1988
Treatment Anolication:
Type of Action: Remedial
Period of operation: January 1992 through
December 1995 (Performance data collected
through December 1995)
Quantity of material treated during
application: 281 million gallons of
groundwater, and 25 million gallons of surface
water.
Historical Activity that Generated
Contamination at the Site: Industrial waste
disposal
Corresponding SIC Code: 4953E (Waste
management-refuse systems; sand and gravel
pit disposal)
Waste Management Practice That
Contributed to Contamination: Unlined
disposal pit (lagoon)
Location: Crosby, TX
Facility Operations:
• The French Limited site is a 22.5-acre tract
of land located adjacent to Highway US-90
in eastern Harris County, Texas. The site is
in the floodplain of the San Jacinto River
and was used for sand mining in the 1960s
and 1970s. During the period of 1966
through 1971, the site was permitted by the
State of Texas to accept industrial waste
material for disposal in a 7-acre lagoon
created from an open sand pit. About 80
million gallons of waste material was
disposed of in the main waste lagoon,
creating 300,000 cubic yards of
contaminated sludges and soils. The
facility's permit was revoked and the site
was closed in 1973.
• In 1981, a flood caused the dike surrounding
the waste lagoon to breach and in 1982,
EPA repaired the dike, and pumped most of
the discharged sludges back into the
lagoon.
A remedial investigation was performed
from 1983 to 1986 through a cooperative
agreement. The French Limited Task
Group (FLTG), a private company formed
by potentially responsible parties (PRP),
conducted a 1986 Field Investigation and
prepared a Supplemental Remedial
Investigation Report; using the results to
select the site remedy.
In April 1987, the responsible parties
conducted a slurry-phase bioremediation
pilot demonstration. Based on the results of
the demonstration, EPA selected slurry-
phase bioremediation as the preferred
remedial technology for lagoon sludges and
contaminated soils in the EPA Record of
Decision (ROD), dated March 24,1988.
The 1988 ROD also specified extraction and
treatment of contaminated groundwater with
in situ bioremediation to enhance
contaminant reductions. This report focuses
on the groundwater remedial activities.
In 1989, as a source control measure, the 7-
acre lagoon was isolated and contained
within a wall of double-interlock, steel sheet
pile that surrounded the lagoon, and keyed
into the second clay unit. The sheetpile wall
is also called the floodwall.
Beginning in January 1992, the
contaminated sludges and soils within the
lagoon were treated in place using slurry-
phase bioremediation. Treatment of the
soils and sludges was completed in
December 1993. A Cost and Performance
EPA
U.S. Environmental Protection Agency
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Technology Innovation Office
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SITE INFORMATION (CONT.)
Backaround (Cont.)
report (Reference #7) describes the slurry-
phase bioremediation of lagoon sludges and
soils.
• The site was placed on the National
Priorities List (NPL) in 1981.
Regulatory Context [26]:
• A ROD was signed on May 1987 and
amended on March 24,1988.
• Site activities are conducted under
provisions of the Comprehensive
Environmental Response, Compensation,
and Liability Act (CERCLA) of 1980, as
amended by the Superfund Amendments
and Reauthorization Act (SARA) of 1986
§121, and the National Contingency Plan
(NCP), 40 CFR 300. Post-closure
monitoring of the upper and lower aquifers
for a period of 30 years is required under
the Resource Conservation and Recovery
Act(RCRA)of 1976.
Site Logistics/Contacts
Remedy Selection [20]:
The contaminated groundwater was extracted
and treated in an aboveground treatment
system. In situ bioremediation was
implemented for the groundwater plume to
expedite the cleanup process. The ROD for this
site allows for 10 years of natural attenuation to
meet final remedial goals. Lagoon sludges were
treated via slurry-phase bioremediation.
Surface water (from the lagoon) was treated in
an aboveground treatment system. Treated
water was discharged to the San Jacinto River.
Site Lead: PRP
Oversight: EPA
Remedial Project Manager:
*Ernest Franke
EPA - Region 6
1445 Ross Avenue
Dallas, TX 75202-2733
214-665-6739
State Contact:
Emmanuel Ndame
Texas Natural Resources Conservation
Commission (TNRCC)
512-239-2444
Indicates primary site contact
PRP:
*Richard L. Sloan
ARCO Chemical Company
FLTG Project Coordinator
15010FM2100, Ste. 200
Crosby, TX 77532
713-328-3541
Prime Contractor:
CH2M Hill
Jon McLeod
512-346-2001
Treatment System Vendor:
Applied Hydrology Associates, Inc.
Mike Day, President
Denver, CO
EPA
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MATRIX DESCRIPTION
Matrlv Iripntifirntinn
Type of Matrix Processed Through the
Treatment System: Groundwater
rVtntnminnnt Characterization F131
Primary Contaminant Groups: Volatile
organic compounds (VOCs)
• Major chemicals in the lagoon sludges
included chlorinated and nonchlorinated
VOCs and semivolatile organic compounds
(SVOCs), polychlorinated biphenyls (PCBs),
and polycyclic aromatic hydrocarbons
(PAHs). Dense non-aqueous phase liquid
(DNAPL), containing a significant
component of VOCs, also migrated into the
underlying subsoils. Leaching lagoon
sludges and contaminated subsoils resulted
in a dissolved groundwater plume of VOCs
extending approximately 600 feet
downgradient (south) of the site.
• Contaminants of concern in the groundwater
were benzene, toluene, chloroform, 1,2-
dichloroethane (1,2-DCA), and vinyl
chloride. Benzene was the most prevalent
organic compound. 1,2-DCA was the
primary chlorinated solvent compound
found in the DNAPL in the source areas.
Initial maximum detected levels of selected
contaminants were benzene (19,000 ug/L),
vinyl chloride (8,200 ug/L), and 1,2-DCA
(920,000 ug/L).
• Figures 1 and 2 show the extent of benzene
and 1,2-DCA contamination, respectively, in
the uppermost aquifer (S1) as of December
1991.
• The VOC plume at the site initially consisted
of 91 million gallons of contaminated
groundwater. In the S1 aquifer, the plume
was 500 feet long (north-south) and 1,500
feet wide (east-west), or 750,000 square
feet. In the INT unit, the plume was 950
feet long (north-south) and 1,800 feet wide
(east-west), or 1.7 million square feet. The
plume volume was determined for this
report based on the areal extent of the
plumes, a depth of 20 feet in the S1 aquifer,
a depth of 15 feet in the INT aquifer, and a
standard porosity of 30% [1].
Slight mounding of the water table near the
waste pit indicated slow seepage. Lateral
contaminant migration within the shallow
aquifer was estimated at approximately 80
feet per year.
In January 1992, shortly after the startup of
the pump and treat (P&T) system, DNAPL
was detected at well S1-16 inside the
floodwall and at well INT-11 just outside the
floodwall. A preliminary study conducted by
Applied Hydrology Associates, Inc. (AHA) in
the spring of 1992 confirmed the presence
of DNAPL in the INT-11 area outside the
floodwall. A comprehensive DNAPL field
study was conducted by AHA between
March and July 1993. The subsequent field
data report concluded that the INT-11 area
was the only area where DNAPL was
confirmed to exist outside the sheetpile
floodwall. DNAPL extended up to 63 feet
south of the floodwall and was a continuing
source of contamination to the groundwater.
Construction of a second sheetpile wall
around the DNAPL source area was
completed in August 1994.
EPA
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MATRIX DESCRIPTION (CONT.)
Figure 1. Initial Benzene Concentration Contour Map, S1 Unit
(October - December 1991 baseline sampling) [24]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
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MATRIX DESCRIPTION (CONT.)
Figure 2. Initial 1,2-DCA Concentration Contour Map, S1 Unit
(October - December 1991 baseline sampling) [24]
EPA
U.S. Environmental Protection Agency
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MATRIX DESCRIPTION (CONT.)
Matrix Characteristics Affecting Treatment Costs or Performance
Hydrogeology [13]:
Five distinct hydrogeological units have been identified beneath this site. Groundwater is encountered
approximately 10 to 12 feet below ground surface. Shallow alluvial deposits of Holocene age, consisting
of sands, silts, and clays extend to a depth of 55 feet. These sediments were deposited in the San
Jacinto River flood plain and have been subdivided into the following hydrogeologic units. Table 1
presents technical aquifer information.
Unit 1 S1
Unit 2 C1
Unit 3 INT
Unit 4 C2
(Beaumont
Formation)
Unit 5 S2
(Chicot
Aquifer)
Clean medium to coarse sand with minor amounts of fine gravel. The
unit is comprised of primarily fluvial channel deposits. The French
lagoon was created by mining sand from this unit.
Laterally discontinuous clay with minor thin silt and fine sand layers.
Where present, it functions as an aquitard between the S1 and INT units.
Interbedded fine sand and clayey silts. This unit represents overbank
flood deposits and exhibits a fining-upward sequence with transitional
contact with overlying clays.
Predominantly clay deposit with minor thin silt and fine sand layers. This
unit functions as a major aquitard between the upper alluvial units and
the underlying Chicot aquifer.
A sequence of fluvial-deltaic sands, silts, and clays. This unit (along with
the Evangeline aquifer beneath it), composes the primary water supply
aquifer in this area. This unit is not contaminated.
Table 1. Technical Aquifer Information [13]
Unit Name
S1
C1
INT
C2
S2
Depth Below
Surface
(ft)
10-35
0-4
40-55
70
NA
Conductivity
(ft/day)
2.835
—
0.283
—
NA
Average
Velocity
(ft/day)
NA
—
NA
—
NA
Flow Direction
S/SE
—
S/SE
—
NA
NA- Data not included in documentation.
Source: [13]
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TREATMENT SYSTEM DESCRIPTION
Pump and treat (P&T) with activated sludge for
extracted groundwater. In situ bioremediation
for contaminated groundwater.
and Operation
Supplemental Treatment Technology
Carbon adsorption, metals precipitation, and
neutralization
Well Name
(Number of Wells)
Pumping wells (53)
Pumping wells (56)
Injection wells (17)
Infection wells (42)
Unit Name
S1
INT
S1
INT
Depth (ft)
35
55
35
55
Yield (qal/min)
1.8
0.6
2.3
0 7
source: [1,14]
System Description [19]
• Groundwater at the French Limited site was
actively remediated from January 1992
through December 1995 via a combination
of conventional pumping and above-ground
treatment, enhanced aquifer flushing
through pressure injection of clean water,
and accelerated in situ bioremediation
through the addition of dissolved oxygen,
diammonium phosphate, and nitrate to
injection water. The aboveground treatment
unit operations included equalization,
biological treatment, metals precipitation,
clarification, filtration, neutralization and
carbon adsorption (polishing).
• Source control was achieved by installing
cutoff (sheet-pile) walls around the lagoon
in 1989 and around the DNAPL source area
in 1994. The sheet-pile wall around the
lagoon is referred to as the floodwall and
consists of 996 sheet-pile pairs. The total
length of the floodwall is 2,090 feet. The
top of the floodwall is 3 feet higher than the
100-year flood level. The bottom of the 65-
to 75-foot-long sheet-piles is keyed into the
clay stratum underlying the INT unit [27].
• A phased groundwater remediation strategy
was developed for this site. The strategy
involved installing unit operations in
incremental steps to verify design
assumptions for P&T enhanced by in situ
bioremediation. The first phase of the
groundwater strategy was aimed at
hydraulic containment of all groundwater
that exceeded cleanup criteria. The in situ
bioremediation equipment was next
installed to enhance contaminant reduction.
The metals precipitation unit was added
later when the activated sludge system
failed to sufficiently remove metals. Effluent
from the treatment system was discharged
to the San Jacinto River under a state
discharge permit, following treatment to the
State of Texas standards.
The in situ bioremediation sequence of
flushing, nitrifying conditions, and finally
aerobic conditions was designed to
stimulate different types of microorganisms.
This design created cometabolic
biodegradation processes to biodegrade a
wide variety of chlorinated and
nonchlorinated constituents throughout the
plume. First, clean water only (no added
nitrate or oxygen) was injected for 30 days.
Second, the nitrate and diammonium
phosphate was mixed with clean water and
injected for 90 days. Finally, the oxygen
was mixed with clean water and injected for
44 months.
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TREATMENT SYSTEM) DESCRIPTION (CONT.)
System Description and Operation fConU
• Table 2 shows well-specific extraction rates.
The goal of well placement was hydraulic
containment. Most wells were located
downgradient (outside) of the floodwall, to
intercept the larger portion of the plume and
contain the plume. The wells located inside
the floodwall were used to contain DNAPLs
within the floodwall area.
• The injection and extraction system
consisted of 109 recovery wells and 59
injection wells; 53 recovery wells and 17
injection wells for the S1 unit and 56
recovery wells and 42 injection wells for the
INT unit.
System Operation
• Quantity of groundwater pumped from
aquifer by year:
Year
1992
1993
1994
1995
Total Volume
Pumped
(gal)
42.8 million
13.2 million
68 million
13.6 million
54 million
26 million
24.5 million
23.4 million
Unit Name
S1
INT
S1
INT
S1
INT
S1
INT
The P&T system at this site was operational
nearly 90% of the time. Major causes of
groundwater extraction system downtime
included problems with pneumatic pumps,
flow meters clogging, air valves locking,
surface leaks in injection wells, and low
yields in several INT extraction wells [1].
1.5 million pounds of carbon was used in
the water treatment plant from 1992 through
1995.
The nitrate additive for in situ
bioremediation was controlled so that the
concentration of nitrate in the groundwater
did not exceed the drinking water standard
of 10 mg/L. The oxygen concentration in
the injected water was maintained between
35 and 40 mg/L.
Active pumping of groundwater at this site
was stopped in December 1995. Natural
attenuation has been allowed to reduce the
remaining concentrations of contaminants
where possible. In March 1998, the FLTG
began adding liquid oxygen in areas where
contaminants persisted along with a
focused groundwater pumping program.
This allowed the site operators to control
and monitor the spread of increased
dissolved oxygen (DO) levels and to
enhance bioremediation.
EPA
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TREATMENT SYSTEM DESCRIPTION (CONT.)
Operating Parameters Affecting Treatment Cost or Performance [161
Table 3 presents major operating parameters affecting performance.
Table 3: Performance Parameters
Parameter
Average Extraction Rate
Performance Standards
(effluent)
Remedial Goal for Target
Compounds (aquifer)
Value '~ *
189gpm
TNRCC discharge permit limits for the San Jacinto River
PH
TSS
Benzene
Halogenated VOCs
Napthaiene
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Zinc
Vinyl Chloride
Benzene
Toluene
1,2-DCA
Chloroform
6-9
55 mg/L
150 Mg/L
500 ug/L
300 ug/L
150 |jg/L
i,ooo|jg/L
50 Mg/L
500 Mg/L
15 Mg/L
66 ug/L
300 Mg/L
iug/L
148 ug/L
20 Mg/L
5 Mg/L
162 Mg/L
2 Mg/L
5 Mg/L
1,000 Mg/L
100 Mg/L
100 Mg/L
Source: [16]
Table 4 presents a timeline for this remedial project.
Table 4: Project Timeline
Start Date
_.
1981
1982
03/87
03/88
04/90
1991
1989
01/92
01/92
03/93
08/94
12/95
End Date
1973
1987
„
_„
12/90
...
...
_.
07/93
—
—
Activity
M: -ill -life- '^
Site closed to receiving wastes
Site listed on NPL
EPA and PRP remedial investigations, feasibility studies, and pilot studies conducted
ROD signed
Amended ROD signed
Remedial system designed
Construction completed
First sheetpile floodwall installed around lagoon
Site remediation operations begun (operational and functional letter)
DNAPL detected in S1 and INT extraction wells
Comprehensive DNAPL field study conducted
Second sheetpile wall installed to contain DNAPL residue found outside original sheetpile floodwall
Active site remediation completed. 1 0-year timef rame to achieve ground water cleanup criteria through
natural attenuation begun.
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TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards T201
The 1988 ROD states: "Groundwater recovery
and treatment will continue until modeling shows
that a reduction in the concentration of volatile
organics to a level which attains the 10"6 human
health criteria (listed in Table 3) at the site
boundary can be achieved through natural
attenuation in 10 years or less."
Additional Information on Goals
The aquifer remediation compliance point is the
point of first public exposure downgradient from
the site (i.e., the first point where someone
could install a potable water well in the shallow
alluvial aquifer). The PRPs own the site and
much of the surrounding property to limit the
point of first public exposure. The compliance
point is located along Gulf Pump Road toward
the Riverdale subdivision.
Treatment Performance Goals F201
The primary goal of the remedial system
was plume containment, accompanied by in
situ bioremediation and source control via
sheetpile walls.
Pprfnrmancp Data Assessment F10.13-18. 281
The secondary goal of the P&T system was
to reduce effluent contaminant levels to
meet TNRCC discharge permit
requirements for discharge to the San
Jacinto River. Table 3 lists effluent permit
requirements.
A natural attenuation modeling study
conducted in late 1995 demonstrated that
natural attenuation would reduce
groundwater contaminant concentrations
below the remedial goals at the site
boundaries within 10 years after system
shut-off. The October 1,1995 data were
used as starting conditions for the natural
attenuation study. Visual MODFLOW and
BloTrans were used for modeling purposes.
As a result, EPA allowed the groundwater
recovery and treatment operations to be
shut down in December 1995.
In May 1994, one well in a downgradient
residential subdivision showed levels of
vinyl chloride at 7 ug/L. Other wells
sampled in the area showed no
contaminants above detection limits. No
contaminants have been detected in
downgradient monitoring wells since
May 1994, indicating successful plume
contaminant at that time.
Figure 3 illustrates how contaminant
concentrations in the groundwater have
changed in the S1 unit. Wells S1-108,
S1-109, and S1-111 in the S1 unit (all
located outside the floodwall) were used to
illustrate the trend. These wells are evenly
spaced along the downgradient side of the
lagoon. A geometric mean of the data from
all three wells was calculated and presented
in the figure. The figure shows declining
concentrations for benzene, 1,2-DCA, and
vinyl chloride from 516 to 0.6 ug/L,
256 to 0.8 ug/L, and 129 to 1.2 ug/L,
respectively.
Figure 4 illustrates how contaminant
concentrations in the groundwater have
changed in the INT unit. Wells INT-102,
INT-104, INT-108, INT-109, and INT-110 in
the INT unit (all located outside the
floodwall) were used to illustrate the trend.
A geometric mean of the data was
calculated and presented in Figure 4. The
figure shows declining concentrations for
benzene, 1,2-DCA, and vinyl chloride from
640 to 2 ug/L, 917 to 1 ug/L and 420 to 1
ug/L, respectively.
EPA
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TREATMENT SYSTEM PERFORMANCE (CONT.)
1,000
a 100
§
I
12/28/91 7/15/92
1/31/93
8/19/93
3/7/94
9/23/94
4/11/95 10/28/95
-1,2-DCA
-Vinyl Chloride
•Benzene
Figure 3. Average Groundwater Concentrations in S1 Unit (1992 -1995) [5,28]
1,000
100
I
12/28/91 7/15/92 1/31/93 8/19/93 3/7/94 9/23/94 4/11/95 10/28/95
-1,2-DCA
-Vinyl Chloride
-Benzene
Figure 4. Average Groundwater Concentrations in INT Unit (1992 -1995) [5,28]
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TREATMENT (SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment (Cont.)
Figure 5 presents the mass flux and
cumulative removal of contaminants
through the treatment system from 1992 to
1995. Mass flux through the treatment
system varied between 170 Ibs/day and 735
Ibs/day. From 1992 to December 1995, the
P&T system removed 517,000 pounds of
contaminant mass (measured as TOC) from
the groundwater.
The contaminant removal rate has not
followed the expected asymptotic decline as
seen in typical P&T applications. Likewise,
the cumulative mass removal data have not
reached a plateau as seen in typical P&T
applications.
No data were available to quantify the
amount of contaminants destroyed through
bioremediation.
Jun-91 Dec-91 Jul-92 Jan-93 Aug-93 Mar-94 Sep-94 Apr-95 Oct-95 May-96
- Mass Flux
• Mass Removed
Figure 5. Mass Flux Rate and Cumulative Contaminant Removal (1992 - 1995) [15,16]
Performance Data Completeness
Monthly data on treatment performance are
available in annual groundwater monitoring
reports.
Monthly influent rates to the treatment plant
and yearly average total organic carbon
(TOC) data were provided by the site
contact in a correspondence dated April 20,
1998 [12].
Data on groundwater concentrations were
reported in figures included in the Five Year
Review as well as annual groundwater
reports [5,16-18].
Contaminant mass removal data were
provided in annual monitoring reports.
Mass removal was calculated with TOC
data. Actual TOC composition was not
available.
EPA
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TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Oualitv
The QA/QC program used throughout the remedial action met the EPA and the State of Texas
requirements. All monitoring was performed using EPA-approved methods, and the site contact did not
note any exceptions to the QA/QC protocols.
TREATMENT SYSTEM COST
Procurement Process
FLTG was responsible for the design, construction, and operation of the remedial action at the French
Limited site. Oversight was provided by EPA Region 6 and TNRCC. The EPA oversight contractor was
CH2M Hill. The design, construction, operation, and maintenance contractors were ENSR, Bechtel,
ROG, AHA.
All costs for investigation, design, construction, and operation of the treatment system at this site
were borne by the 76 PRPs that comprise the FLTG. Costs for the two sheet-pile walls are included
under capital costs because they are an integral part of containing the groundwater contaminant
plume.
Capital Costs F251
Site Preparation
Sitework Construction $300,000
Site Facility $1,250,000
Installation of wells and piping $3,000,000
Groundwater P&T Facility $3,500,000
Nutrient Addition Facilities $100,000
Sheet-pile Floodwall-Lagoon
Construction $4,000,000
Sheet-pile Wall-DNAPL
Construction $230,000
DNAPL Response $507,000
Demobilization $2,600,000
Total Capital Cost $15,487,000
Operating Costs F251
Operations and Maintenance $11,000,000
Admin/Site Management
Project Coordinator $462,000
Project Manager $287,500
Project Control $1,088,000
Security $364,500
FLTG Tech. Oversight $5,000,000
Total Operating Costs (1992- $18,202,000
1995)
Other Costs F251
Design
Engineering Design $700,000
Engineering Design Floodwall $260,000
Engineering Design Sheetpile $15,000
Wall
Cost Data Quality
Cost data were provided by the site contact. No independent analysis has been performed to provide
quality control of cost data.
EPA
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OBSERVATIONS AND! LESSONS LEARNED
Actual costs for the P&T and in situ
bioremediation were $33,689,000
($15,487,000 in capital costs and
$18,202,000 in operating and maintenance
costs) corresponding to unit costs of $110
per 1,000 gallons treated and $15 per pound
of contaminant removed.
This site met requirements specified in the
ROD that allowed it to shut down the
groundwater treatment system within three
years of operation. Computer models
predict that groundwater concentrations will
meet final cleanup criteria by December
2005. Land surrounding the site has been
purchased by PRPs to provide a buffer zone
until the groundwater concentrations have
been reduced to below cleanup criteria.
The treatment system performance data
indicate that approximately 517,000 pounds
of contaminants were removed from the
groundwater over three years.
Treatment costs at this site are relatively
high. This may be due, in part, to the
combined efforts of a P&T system, an in situ
bioremediation system, and source control
measures. Sheet pile walls were
constructed around the lagoon and the
DNAPL source area at a cost of $4,230,000.
The ROD for this site included a provision to
allow for 10 years of natural attenuation to
meet final remedial goals. Groundwater
flow and contaminant transport models were
relied upon to predict compliance within 10
years after pumping ceased.
This treatment application was part of a
multifaceted cleanup program. The
remedial program at this site included
source control, in situ bioremediation, and
P&T. The site contact reported that the
combination of cleanup efforts resulted in
successful remediation of the site within a
reasonable time frame [3].
REFERENCES
1. Correspondence between Richard Sloan,
FLTG Representative, and Lynn Gilbert,
Dyncorp, Inc., September 1, 1994.
2. French Buy-Out Proposal, March 12,1996.
3. Correspondence between Richard Sloan,
FLTG Representative, and David Boram,
ERG, June 25, 1997.
4. Site Remediation Report. FLTG, Inc.
January 16, 1995.
5. Five Year Review. CH2M Hill, January 26,
1995.
6. EPA Fact Sheet, French Ltd., November 5,
1997.
7. Cost and Performance Report, Slurry-Phase
Bioremediation at the French Limited
Superfund Site. U.S. EPA, March 1995.
8. FLTG Memo, "Aquifer Remediation Review,
December 10-11,1992," January 18,1993.
9. FLTG Memo, "Pulse Pumping Plan,"
Octobers, 1993.
10. Natural Attenuation Modeling Report.
Applied Hydrology Associates, December
1995.
11. Hydraulic Characterization of a Superfund
Site: Remedial Investigation Through
Remedial Action, O'Hayre A.P., April 1993,
Proceedings of the Georgia Water
Resources Conference, April 20-21, 1993.
12. Correspondence between Richard Sloan,
FLTG Representative, and Charlie Carter,
ERG, April 20, 1998.
13. Evaluation of Stratiqraphic Controls on
DNAPL Migration. Applied Hydrology
Associates, September 1995.
14. Monthly Progress Report, FLTG, Inc.,
December 1994.
EPA
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Office of Solid Waste and Emergency Response
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REFERENCES (CONT.)
15. Monthly Progress Report. FLTG, Inc., July
1994.
16. Annual Groundwater Monitoring Report.
December 1994, FLTG, Inc., March 1995.
17. Annual Groundwater Monitoring Report.
December 1993, FLTG, Inc., March 1994.
18. Annual Groundwater Monitoring Report
December 1992. FLTG, Inc. March 1993.
19. "In situ Bioremediation of Groundwater and
Subsoils at the French Limited Site, Texas,"
Biotreatment News.
20. "Remediation Facilities Design Report,"
ENSR Consulting and Engineering. June
1991.
21. In situ Bioremediation at the French Limited
Site. Woodward R., IGT Symposium
December 11-13,1989.
22. "French Limited: A Successful Approach to
Bioremediation," Biotreatment News.
December 1992.
Analv<;is Prenaration
23. "Reverse Osmosis Reverses Conventional
Wisdom with Superfund Cleanup Success,"
Mark Collins and Ken Miller, Wastewater
Management. September 1994.
24. Correspondence between Richard Sloan,
FLTG Representative, and Charlie Carter,
ERG, April 1, 1998.
25. Correspondence between Will Schorp,
FLTG Representative and Charlie Carter,
ERG, Aprils, 1998.
26. U.S. Environmental Protection Agency,
Record of Decision. March 24, 1988.
27. Evaluation of Subsurface Engineered
Barriers at Waste Sites. U.S. EPA/OERR,
September 30,1998.
28. 1995 Annual Aguifer Sampling Report.
FLTG, Inc., March 1996
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
90
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Pump and Treat and Air Sparging of Contaminated Groundwater at
the Gold Coast Superfund Site,
Miami, Florida
91
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Pump and Treat and Air Sparging of Contaminated Groundwater at
the Gold Coast Superfund Site,
Miami, Florida
Site Name:
Gold Coast Superfund Site
Location:
Miami, Florida
Contaminants:
Chlorinated solvents and
volatiles - nonhalogenated
(toluene)
- Maximum initial concentrations
were methylene chloride (100
ug/L), 1,1-DCA (2,000 ug/L),
trans-l,2-DCE (3,000 ug/L), TCE
(48,000 ug/L), PCE (100,000
ug/L), and toluene (545 ug/L)
Period of Operation:
7/90 - 3/94: pump and treat
11/94 - 2/95: air sparging
Cleanup Type:
Full-scale cleanup
Vendors:
Construction: Simmons Consulting,
Inc.
Treatment System Vendor: Lantec
Operations: Simmons Consulting,
Inc., and The Balijet Corp./Edward
E. Clark Engineers-Scientists, Inc.
State Point of Contact:
Marvin Collins
Florida Department of
Environmental Protection (FDEP)
Tallahassee, FL
(850)488-0190
Technology:
Pump and Treat and Air Sparging
- Groundwater was extracted using
five wells, located on site, at an
average total pumping rate of 44
gpm
- Extracted groundwater was
treated with air stripping and
reinjected into the aquifer through
three injection wells
- Groundwater was sparged with a
portable sparger and contaminants
were allowed to volatilize
Cleanup Authority:
CERCLA Remedial
-ROD Date: 9/11/87
EPA Point of Contact:
Brad Jackson, RPM
U.S. EPA Region 4
3456 Courtland Street, N.E.
Atlanta, GA 30365
(404) 562-8975
Waste Source:
Direct discharge of solvent
reclamation blowdown to soil;
improper storage of waste
Purpose/Significance of
Application:
Met goals within four years of
operation; included pump and treat
and air sparging
Type/Quantity of Media Treated:
Groundwater
- 80 million gallons treated as of February 1996
- DNAPL observed in groundwater on site
- Groundwater is found at 5 ft bgs
- Extraction wells are located in one aquifer and are influenced by a
nearby surface water
- Hydraulic conductivity was reported as 1,000 ft/day
Regulatory Requirements/Cleanup Goals:
- The remedial goal was to reduce contaminant concentrations throughout the aquifer to levels below the
maximum contaminant levels (MCLs) set by the FDEP, DERM, and primary drinking water standards.
- Remedial goals were identified for 1,1-DCA (5 ug/L), trans-l,2-DCE (70 ug/L), methylene chloride (5 ug/L),
PCE (0.7 ug/L), TCE (3 ug/L), and toluene (340 ug/L).
- Effluent from the treatment system was required to meet the remedial goals prior to re-injection.
- A secondary goal was identified to create an inward gradient toward the site to contain the plume.
92
-------
Pump and Treat and Air Sparging of Contaminated Groundwater at
the Gold Coast Superfund Site,
Miami, Florida (continued)
Results:
- Groundwater monitoring results indicate that contaminant concentrations have been reduced below treatment
goals; from 1991 to 1994, 1,961 Ibs of TCE and PCE were removed from the groundwater.
- Optimization efforts were used to focus cleanup on the problem areas at the site; excavation of soil suspected
to contain DNAPLs and groundwater sparging were performed to complete cleanup of problem areas.
- Performance monitoring results indicate that effluent requirements have been met throughout the operation of
the treatment system.
- No contaminants were detected in downgradient monitoring wells during remedial operations, indicating that
the plume was contained throughout the remedial action.
Cost: -
- Actual cost data were provided by the responsible parties for this application.
- Costs for pump and treat were $694,325 ($249,005 in capital and $445,320 in O&M), which correspond to $9
per 1,000 gallons of groundwater extracted and $354 per pound of contaminant removed.
Description:
Gold Coast Oil Corporation operated as a spent oil and solvent recovery facility from 1970 to 1982. Recovery
operations at the 2-acre site included distillation of lacquer thinner and mineral spirits; blowdown from these
operations was discharged directly onto the soil. In 1980, the FDEP detected soil and groundwater
contamination in on-site soil (heavy metals and organics) and an off-site groundwater well (VOCs). The site was
placed on the NPL in September 1983 and a ROD was signed in September 1987.
Five extraction wells were constructed in the Biscayne Aquifer at the site. Three wells were installed to a depth
of 15 ft, with a design yield of 10 gpm; two wells were installed to a depth of 30 ft, with a design yield of 35
gpm. Extracted groundwater was treated using two air stripping towers in series, with each tower 36 ft high, 3 ft
diameter, and packed to 26 ft with IMPAC, a material that enhances stripping of VOCs from water. Treated
groundwater was re-injected into the aquifer through three injection wells.
Cleanup standards were met at this site within approximately four years of operation. Cleanup was achieved
after excavation of soil suspected to contain DNAPLs and groundwater snareine were nerformed
93
-------
Gold Coast Superfund Site
Identifying Information:
Gold Coast Superfund Site
Miami, Florida
CERCLIS#: FLD071307680
ROD Date: September 11,1987
jBaekflrpund
SITE INFORMATION
Treatment Application:
Type of Action: Remedial
Period of operation: 7/90 - 3/94
(Data collected through February 1996)
Quantity of material treated during
application: 80 million gallons of groundwater
Historical Activity that Generated
Contamination at the Site: Spent oil and
solvent reclamation
Corresponding SIC Code: 4953W
(Miscellaneous Waste Processing)
Waste Management Practice That
Contributed to Contamination: Direct
discharge of reclamation blowdown to the soil;
improper storage of waste
Location: Miami, Florida
Facility Operations: [1,7]
• Gold Coast Oil Corporation operated as a
spent oil and solvent recovery facility from
1970 to 1982. Recovery operations at the
2-acre site included distillation of lacquer
thinner and mineral spirits. Blowdown from
these operations was discharged directly
onto the soil.
- In 1980, the FDEP detected soil and
groundwater contamination from sampling
on-site soil and an on-site well.
• In 1981, the FDEP, DERM, and the EPA
conducted soil and groundwater
investigations. Soils were found to be
contaminated with heavy metals and
organics; groundwater was found to be
contaminated with VOCs.
In 1982, facility operations ceased. The
remaining hazardous liquid and solid waste
was disposed off site by the owners.
• Visibly contaminated soil was excavated
from the site in 1982 and disposed off
site. After excavation, the remaining
soils were tested. According to the Site
Closeout Report, no contamination was
detected in the remaining soils [8]. Had
contamination been detected, the plan
was to solidify and stabilize the soils [8].
From 1982 until 1990, additional
remedial investigations were performed.
As part of these investigations, 15
monitoring wells were installed at the
site.
In September 1983, the site was placed
on the National Priorities List (NPL).
Regulatory Context:
EPA issued a ROD on September 11,
1987.
• Site activities were conducted under
provisions of the Comprehensive
Environmental Response,
Compensation, and Liability Act of 1980
(CERCLA), as amended by the
Superfund Amendments and
Reauthorization Act of 1986 (SARA)
§121, and the National Contingency
Plan (NCP), 40 CFR 300.
Groundwater Remedy Selection: The
selected groundwater treatment was
extraction of the groundwater followed by
treatment using an air stripper, with treated
groundwater being re-injected into the upper
Biscayne Aquifer.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
94
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Gold Coast Superfuncf Site
Srrfe INFORMATION (CONT.)
nniQtif;
-------
Gold Coast Superfund Site
MATRIX DESCRIPTION (CONT.)
tr:*
DELTA GAS CO.
SUPER TRACK
17
PRIOR TO REMEDIATION (03/01/90-07/16/90)
DELTA GAS CO.
SUPER TRACK
17
• 9 -'''
FIRSTvYEAR OF REMEDIATION (07/16/90-07/24/91)
«•• •• *«• ww Aotuooft CbfutUuent Pttme
Dn»plR«iidutlZone
(AJsbDNAPLEnayZooe)
80 120 190
Figure 1. DNAPL and Plume Distribution (1990 - 1991) [7]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
96
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Gold Coast Superfund Site
MATRIX DESCRIPTION (CONT.)
PROPERTY FENCE UHE
"Cfrmv:
PROPERTT FENCE LINE
._..„.. j_.
DELTA GAS CO.
SUPER TRACK
17
•9
SECOND* YEAR OF REMEDIATION (07/24/91.07724/921
••
-------
Gold Coast Superfund Site
MATRIX DESCRIPTION (CONT.)
DELTA GAS (0.
SUPER TRACK
WOPffiTTHIKEUH]:
17
's
• 9
FOURTH YEAR OF REMEDIATION (SAMPLED ON 11/1/93)
"UT.:
DELTA GAS CO.
SUPER TRACK
MOPffiTT FENCE LINE
17
•S
FOURTH YEA« OF REMEDIATION (SAMPLED ON 12/15/93)
-._ — .- Aquwut Coratituent Plume
(AlwDNAPLEnnyZonc)
80 120 160
Figure 3. DNAPL and Plume Distribution (1993) [7]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
98
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6ofd Coast Superfuncf Site
MATRIX DESCRIPTION (CONT.)
Matrix Characteristics Affecting Treatment Costs or Performance
Hydrogeology [1, 2, 7]:
Two distinct hydrogeologic units have been identified beneath this site.
Unit 1 Biscayne Aquifer
Unit 2 Floridan Aquifer
The Biscayne Aquifer is the sole source of drinking water for the
area. It lies approximately 5 feet below the ground surface [7].
The upper layers of the aquifer are composed of sand, shell, and
unconsolidated limestone. Hard condensed limestone with layers
of thick solution-riddled limestone are found in the lowest layers.
The Miami Oolite and Fort Thompson formations, which consist of
consolidated limestone divided by a layer of hard sand, form the
base of the Biscayne Aquifer. At the site, the aquifer ranges in
thickness from approximately 100 to 110 feet. Unit 1 is not
hydraulically connected to the deep aquifer, Unit 2. Regionally,
groundwater flow is to the east with a very low hydraulic gradient.
However, groundwater flow is governed locally by the nearby
Coral Gables and Tamiami Canals and will change direction
depending on canal water levels [2].
The saline Floridan Aquifer is a deep aquifer separated from the
Biscayne Aquifer by the Tamiami and Hawthorne Formations.
The Tamiami and Hawthorne formations reach a depth of
approximately 700 feet and consist of sand, silt, marl, and clay
materials [2]. This aquifer has not been sampled at this site.
Tables 1 and 2 present technical aquifer information and well data, respectively.
Table 1. Technical Aquifer Information [6]
Thickness
(ft)
Conductivity
(ft/day)
Average Velocity
(ft/day)
Flow
Direction
Unit Name
Biscayne Aquifer
Floridart Aquifer
a As measured by Howard Klein in Biscayne Aquifer, Southeast Florida: U.S. Geological Survey Water Resources
Investigations Report 78-107.
b Groundwater flow direction is governed locally by the nearby Coral Gables and Tamiami Canals and will change direction
depending on canal water levels. .. .
100-110
700
1,000a
NA
2.0
NA
Eastb
NA
EPA
U.S. Environmental Protection Agency
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Technology Innovation Office
99
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Gold Coast Superfund Site
TREATMENT SYSTEM DESCRIPTION
Pump and treat with air stripping
Svstem Descriotion and Ooeration
Supplemental Treatment Technology
None
Table 2. Technical Well Data [6]
Well Name
MW-10
MW-11
MW-13
MW-16
MW-20
Unit Name
Biscayne Aquifer
Biscayne Aquifer
Biscayne Aquifer
Biscayne Aquifer
Biscavne Aauifer
Deoth (ffl
15
15
15
30
30
Design Yield
(gom)
10
10
10
35
35
System Description [2,3,7]
• The extraction system was a network of five
extraction wells, with three wells at depths
of 15 feet and two wells at depths of 30 feet.
Figure 1 shows the site layout and well
locations. Two of the three shallow wells,
MW-11 and MW-13, were located in
suspected DNAPL source zones along the
western edge of the former on-site building.
The two deeper wells were located in the
same source zone as MW-13. The third
shallow monitoring well was located along
the eastern, downgradient edge of the
plume. Well locations were selected to
pump from the most contaminated areas
and to contain the plume. The overall
average pump rate, based on a 95%
operation rate and a total of 80 million
gallons extracted, was approximately 44
gpm.
• The treatment system consisted of two air
stripping towers in series, two holding tanks,
and associated pumps and valves. Each
stripping tower was 36 feet high and 3 feet
in diameter and packed to a height of 26
feet with IMPAC, a packing material that
enhances stripping of VOCs from water.
• Groundwater was pumped through the
stripping towers, into the holding tanks, and
re-injected into the aquifer through three
injection wells.
System Operation [6,7,8]
• Quantity of groundwater pumped from
aquifer in gallons:
Year
July 1990-1991
1992
1993
March 1994
Volume Pumped
(gai)
29,736,200
28,560,200
20,297,890
1,060,950
EPA
U.S. Environmental Protection Agency
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Technology Innovation Office
100
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Gold Coast Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation (Cont.)
From 1990 to 1994, the system was
operational 95% of the time. The system
was shut down for routine maintenance and
during August 1992 as a result of power
outages from Hurricane Andrew. The
system was not damaged by the hurricane.
Extraction wells MW-11 and MW-13 were
pumped throughout system operation
because they were located in suspected
source zones. The other extraction wells
were pumped sporadically and at lower
rates.
In July 1991, wells MW-11 and MW-13 were
enlarged from 2-inch diameter to 4-inch
diameter wellpoints to increase extraction
rates.
In February 1992, pumping began from
MW-10.
Because elevated levels of TCE and PCE
persisted in MW-11 and MW-13, EPA and
the site engineer decided to consider
alternative efforts to capture further
contamination. The maximum TCE and
PCE levels detected during monthly
sampling events persisted at levels up to 10
ug/L and 30 ug/L, respectively. (The
cleanup goals were 3.0 ug/L for TCE and
0.7 ug/L for PCE.) Hydrogen peroxide was
added to MW-11 and MW-13 from March
through July 1993. However, the elevated
contaminant levels persisted in MW-11 and
MW-13, which indicated the likely presence
of a subsurface source zone, or DNAPL [7].
In August 1993, EPA and the site engineer
tried another alternative. The extraction
system was shut down to increase the
amount of TCE and PCE desorbing from
aquifer materials into the groundwater.
Monitoring continued through the shutdown.
The extraction system was restarted in
November 1993. The mass flux into the
treatment system did not increase, and it
was determined the shut-down did not
increase contaminant desorption. Maximum
concentrations of TCE and PCE persisted at
6 ug/L and 24 ug/L.
In March 1994, EPA decided to temporarily
shut down the extraction system while
monitoring continued. Through May 1994,
contaminant concentrations had not
increased and the groundwater treatment
system was officially shut down by the EPA
m.
In November 1994, soil in the areas of
suspected DNAPL contamination was
excavated around wells MW-11 and MW-
13, as approved by EPA. The excavated
soil tested below detection limits for PCE
and TCE. The groundwater was sparged
using a portable sparger and contaminants
were allowed to volatilize in accordance with
EPA correspondence. Subsequent testing
of the groundwater in the excavations
revealed that contaminant levels were
below cleanup goals [7].
Contaminant levels in monitoring wells
sampled from February 1995 through April
1995 did not exceed detection limits.
The wells were decommissioned in April
1995.
The Close-Out Report was signed by the
EPA on February 16,1996, and the site was
deleted from the NPL on August 21,1996.
EPA
U.S. Environmental Protection Agency
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Technology Innovation Office
101
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Gold Coast Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
lnn Paramptprs Affectina Treatment Cost or Performance
Table 3 presents operating parameters affecting cost or performance for this technology.
Table 3. Performance Parameters
Parameter l! v:"' ' '" '
Average Pump Rate
Remedial Goal
(aquifer)
Performance Standard
(effluent)
;.':' • •- , - •"' /, 'vifue ' - , A,/
44gpm
same as performance standards
1,1 -DCA 5.0 ug/L
trans-1,2-DCE 70.0 ug/L
Methylene Chloride 5.0 ug/L
PCE 0.7 ug/L
Toluene 340.0 ug/L
TCE 3.0 ug/L
Note: Average system rate was 44 gallons per minute (gpm), based on a total of 80 million gallons pumped since operations began and a 85%
operation rate.
Source: [1,2]
TlmolInQ
Table 4 presents a timeline for this remedial project.
Table 4. Project Timeline
I "lilgtartTBiie
09/11/87
04/89
01/90
07/90
7/91
2/29/92
10/92
1/93
3/21/93
4/8/93
5/7/93
7/26/93
8/1/93
91/93
3/15/94
11/94
5/16/94
5/94
5/95
End Data
—
—
07/15/90
_
—
_
_
_.
—
—
—
9/1/93
11/1/93
__
2/95
_.
5/95
—
Activity ' .. "
ROD signed
683 tons of soil excavated
Construction of remedial system
Pump and treat system and quarterly monitoring begun
Wells 1 1 and 13 enlarged to 4-inch diameter wells to increase effectiveness
Pumping from MW-10 begun
Concrete base of MW-10 regrouted after hurricane damage
Contaminant levels persist and alternative efforts to increase contaminant capture considered
Hydrogen peroxide injected into wells MW-13 and MW-20
Hydrogen peroxide injected into wells MW-13 and MW-20
Hydrogen peroxide injected into wells MW-13 and MW-20
Hydrogen peroxide injected into wells MW-13 and MW-20
Groundwater extraction system operation ceased for 30-day period in attempt to increase
desorption of TCE and PCE from aquifer to groundwater
Groundwater extraction system operation ceased for 60-day period in attempt to increase
desorption of TCE and PCE from the aquifer to groundwater
Groundwater extraction system stopped operating to allow aquifer equilibration and pending
stability sampling
Soil in suspected source areas excavated and backfilled with clean soil. Groundwater in open pits
sparged
EPA authorizes final shutdown of pump and treat system
Aquifer stability sampling continued through quarterly monitoring
Wells abandoned and site officially shut down bv EPA
Source: [2,4,6]
EPA
U.S. Environmental Protection Agency
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102
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«..'- . V
Gold Coast Superfuncf Site
TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards
The remedial goal for the site was to reduce concentrations of 1,1-DCA, trans-1,2-DCE, methylene
chloride, PCE, toluene, and TCE to levels below the maximum contaminant levels (MCLs) set by the
DERM, FDEP, and Primary Drinking Water Standards. The required cleanup levels are listed above in
Table 3 and are applied throughout the aquifer, as measured in all on-site monitoring wells [1].
Treatment Performance Goals
• Effluent discharged from the treatment
system must meet the remedial goals listed
in Table 3 for re-injection [1,2].
Performance Data Assessment F4.5.7.81
As a secondary goal, the remedial system is
designed to create an inward gradient
toward the site to contain the plume [2].
Groundwater monitoring results indicate that
contaminant concentrations have been
reduced below treatment goals.
Performance monitoring results indicate that
effluent requirements have been met
throughout the operation of the treatment
system.
No contaminants were detected in
downgradient monitoring wells during the
remedial operations. Based on this
information, the plume was contained
throughout the remedial action.
After the first year of operation, the
concentrations of all contaminants except
for TCE and PCE were reduced to levels
below cleanup goals. Elevated levels of
TCE and PCE were detected primarily in
wells MW-11 and MW-13, in the suspected
DNAPL zones.
During remedial system operations, the
contaminant plume was reduced in size, as
shown in Figures 1, 2, and 3. Also shown in
the figures is the location of the residual
DNAPL around wells MW-11 and MW-13.
The estimated distribution of DNAPL
residual decreased each year from 1990
until 1993. In 1994, sampling events did not
indicate the presence of DNAPL.
The performance measures for the Gold
Coast system focused on TCE and PCE
because they were the only contaminants
remaining to be remediated after July 1991.
Figure 4 illustrates PCE and TCE removal
from 1991 to 1994.
Figure 4 shows that from 1991 to 1994,
1,961 pounds of TCE and PCE were
removed from the groundwater. The
removal curve shows the typical flattening
that indicates a reduction in removal
efficiency beginning in the first year and
continuing through the remaining system
operation. In addition, Figure 4 shows that
the mass flux rate declined from 3.4 Ibs/day
during the first year to 0.006 Ibs/day in the
final year.
Figure 5 shows the average levels of TCE
and PCE detected in groundwater from
March 1990 until February 1995. Average
contaminant concentrations in the
groundwater declined from 176 ug/L of PCE
to 8 ug/L of PCE and from 88 |jg/L of TCE
to 9 |jg/L of TCE in the first year.
Contaminant levels were elevated primarily
in wells MW-11 and MW-13. By May 1991,
the average PCE and TCE concentrations
had leveled off, illustrating that the pump
and treat system was not as effective in
decreasing TCE and PCE concentrations.
EPA
U.S. Environmental Protection Agency
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Technology Innovation Office
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Gold Coast Superfund Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
in in Annul in in 11 gii n i it iliiinn
-- 1,700
II 1 If ft rnnnP I If»win i
2,000
1,900
1,800
"8
g
i
1,600 «o
1,500
-- 1,400
1,300
1,200
3
u
Jun-91
Dec-91
Jul-92
Jan-93
Aug-93
Mar-94
Sep-94
-Mass Rux
- Mass Removed
Figure 4. TCE and PCE Mass Flux Hate and Cumulative TCE and PCE Removal
(July 1991 to March 1994) [4, 5]
180
160
140
120
100
Jan-90
May-91
Sep-92
Feb-94
Jun-95
-TCE
-PCE
Figure 5. Average TCE and PCE Concentrations in the Groundwater [4, 5]
EPA
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Gold Coast Superfund Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment (ConU
Figure 6 illustrates the TCE and PCE levels
detected in extraction well MW-11 from
March 1990 until April 1995. Contaminant
levels declined from 89 ug/L of PCE to 13
ug/L of PCE and from 34 ug/L of TCE to 19
ug/L of TCE in the first year of remediation,
but levels of contamination above MCLs
persisted through 1995.
Performance Data Completeness
Figure 7 illustrates TCE and PCE levels
detected in extraction well MW-13 from July
1991 until February 1995. Just as with MW-
11, contaminant levels declined from 44,000
to 680 ug/L of PCE and from 1,700 ug/L to
210 ug/L of TCE in the first year of
remediation, but levels of contamination
above MCLs persisted through 1995. PCE
levels fluctuated from below detection limits
in June 1994 to 94.9 ug/L in October 1994.
For the contaminant concentrations in
Figures 5, 6, and 7, annual monitoring data
were used. Monthly monitoring data are
available from the site contact.
A geometric mean of contaminant
concentrations was used to represent the
trend of contaminant concentrations across
the site.
Performance Data Quality
Contaminant mass removal depicted in
Figure 4 was determined using analytical
results from extraction wells and well
extraction flow rate data. Well data on an
annual basis were used. The mass removal
is, therefore, a best estimate based on
available data. Contaminant concentrations
in the influent and effluent to and from the
treatment system were not available,
because all information was archived.
The QA/QC program used throughout the remedial action met the EPA and the FDEP requirements. All
monitoring was performed using EPA-approved methods, and the vendor did not note any exceptions to
the QA/QC protocols [4].
EPA
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Gold Coast Superfund Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
Jan-90
May-91
Sep-92
Feb-94
Jun-95
TCE
PCE
Figure 6. TCE and PCE Concentrations Detected in MW-11 [4, 5]
900
800
700
600
500
400
300
200
100
Mar-90 Oct-90 May-91 Nov-91 Jun-92 Dec-92 Jul-93 Jan-94 Aug-94 Mar-95 Sep-95
TCE
-PCE
* Concentrations detected during March 1990
** MCLs not shown because of scale limitations
Figure 7. TCE and PCE Concentrations Detected in MW-13 [4, 5]
EPA
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Technology Innovation Office
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Gold Coast Superfund Site
TREATMENT SYSTEM COST
Procurement Process
The group of responsible parties contracted with a private consulting firm to construct and operate the
remedial system, under the oversight of EPA.
Cost Analysis
All costs for investigation, design, construction, and operation of the treatment system at this site were
borne by the group of responsible parties.
Capital Costs F91
Operating Costs F91
Remedial Construction
Startup
Analytical Costs
Tower and Packing
Tower Installation
Well Installation
Construction Management
Total Construction
Cost Data Quality
$14,700
$8,220
$77,110
$6,350
$36,855
$105,770
$249,005
Operation and Maintenance $196,050
Utilities $19,820
Analyses $36,950
Pump Replacement $10,060
Periodic Maintenance $182,440
Cumulative Operating Expenses $445,320
Other Costs F91
Remedial Design
$183,290
Actual capital and operation and maintenance cost data are available from the responsible parties for
this application.
Decommissioning costs were not available. No other costs were incurred that affected cost by greater
than 10%.
OBSERVATIONS AND LESSONS LEARNED
Actual costs for the pump-and-treat
application at Gold Coast were
approximately $694,325 ($249,005 in
capital costs and $445,320 in annual
operation and maintenance costs), not
including design costs, which corresponds to
$354 per pound of contaminants removed
and $9 per 1,000 gallons of groundwater
treated.
The cleanup standards were met at this site
within approximately four years [8]. Within
the first year of operation, the contaminant
levels at the site had been reduced below
cleanup goals with the exception of TCE
and PCE. Only two monitoring wells were
found to have consistently elevated levels
of TCE and PCE. Extraction was then
focused in the area of the two wells [6].
This optimization of extraction well
management allowed cleanup to focus on
the problem areas.
EPA
U.S. Environmental Protection Agency
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Gold Coast Superfund Site
OBSERVATIONS AND LESSONS LEARNED (CONT.)
When pump-and-treat did not quickly
reduce the concentrations of TCE and PCE
in the groundwater, two alternative actions
were evaluated - hydrogen peroxide
injection and stopping extraction for three
months to allow contaminants to desorb
from aquifer materials. However, these
actions did not reduce the levels of TCE and
PCE, indicating they were not as effective
as sparging in quickly removing persistent
volatile organics from the groundwater
given relatively simple hydrogeology [6].
The pattern of persistent and fluctuating
contaminant levels observed in MW-11 and
MW-13 was indicative of a possible
subsurface source area or DNAPL
presence. Cleanup was not achieved until
soil in the areas suspected to contain
DNAPL was excavated and the groundwater
sparged. Because the soil tested clean, it is
likely that the source of the persistent
elevated TCE and PCE levels was removed
through sparging. The excavation likely
helped volatilize contaminants from the
groundwater to the open air.
The porous limestone at the site allowed
groundwater to be extracted without
clogging the wells and enabled easier
installation of wells. Deep wells installed in
bedrock or harder subsurface environments
could have increased cost [6].
REFERENCES
1. Record of Decision. U.S. EPA, September
11, 1987.
2. Remedial Design/Remedial Action Report.
The Baljet Corporation, November 1990.
3. Well Installation Plan. EEC, May 1989.
4. Monthly Reports, through Clark Engineers-
Scientists, November 1991 through May
1995.
5. Technical Impracticability Evaluation for
Further Groundwater Restoration. The
Baljet Corporation, February 24,1994.
6. Five-Year Review. U.S. EPA, November
1994.
7. Site Close-out Report. Edward E. Clark
Engineers-Scientists, Inc. January 18,
1995.
8. Gold Coast Close Out Report. U.S.
EPA, February 1996.
9. Correspondence with Mr. Larry Kirsch
and Mr. Al Simmons, previous site
contacts.
10. Dense Nonaaueous Phase Liquids.
Halin, Scott G. and J.W. Weaver. U.S.
EPA, March 1991.
11. Groundwater Regions of the United
States. Heath, Ralph. U.S. Geological
Survey Water Supply Paper 2242,
1984.
Prpnaration
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 Eastern Research
Group and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the Libby Groundwater Superfund Site,
Libby, Montana
109
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the Libby Groundwater Superfund Site,
Libby, Montana
Site Name:
Libby Groundwater Superfund Site
Location:
Libby, Montana
Contaminants:
Semivolatiles - halogenated (PCP);
andPAHs
- Maximum concentrations
detected during 1986 RI/FS were
PCP (3,200 ug/L), acenaphthene
(100 ug/L), acenaphthylene (200
ug/L), benzo(a)anthracene(l ug/L),
and naphthalene (500 ug/L)
Period of Operation:
Status: Ongoing
Report covers: September 1991
through December 1996
Cleanup Type:
Full-scale cleanup (interim results)
Vendor:
Design: Woodward-Clyde
Consultants
4582 South Ulster Street
Stanford Place 3, Suite 1000
Denver, CO 80237
Operations:
Ralph Heinert
Champion Intl. Corp.
Highway 2 South
P.O. Box 1590
Libby, MT 59923
(406) 293-6238
State Point of Contact:
Neil Marsh
Montana DEQ
Remediation Division
(406)444-0487
Technology:
Pump and Treat and In Situ
Bioremediation
- Groundwater is extracted using 5
wells (3 of which are no longer in
service), at an average total
pumping rate of 16 gpm
- NAPLs are separated from the
extracted groundwater, and the
groundwater is then routed to 2
fixed-film bioreactors in series
- Nutrients (nitrogen and
phosphorus) are added prior to
bioreactors and oxygen is added
within the bioreactors
- Treated water is reinjected
through 2 gravity injection systems
(9 wells total)
Cleanup Authority:
CERCLA Remedial
- ROD Date: 12/30/88
EPA Point of Contact:
Jim Harris, RPM
U.S. EPA Region 8
301 S. Park Drive
P.O. Box 10096
Helena, MT 59626
(406) 441-1150 ext. 260
Waste Source:
Improper storage and disposal of
wood preserving products
Purpose/Significance of
Application:
Combination of pump and treat and
in situ bioremediation at site with
LNAPL, DNAPL, and dissolved-
phase contaminants.
Type/Quantity of Media Treated:
Groundwater
- 15.1 million gallons treated as of December 1996
- DNAPL and LNAPL observed in several monitoring wells on site
- Groundwater is found at 10-20 ft bgs
- Extraction wells are located in 1 aquifer, which is influenced by a nearby
surface water and production wells
- Hydraulic conductivity ranges from 100 to 1,000 ft/day
110
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Pump and Treat and In Situ Bioremediation of Contaminated
Groundwater at the Libby Groundwater Superfund Site,
Libby, Montana (continued)
Regulatory Requirements/Cleanup Goals:
- Remedial goals, developed based on a risk assessment and updated MCLs, were established for non-
carcinogenic PAHs: naphthalene (1,460 ug/L), acenaphthene (2,100 ug/L), fluorene (1,460 ug/L), anthracene
(11,000 ug/L), pyrene (1,100 ug/L), and fluoranthene (1,460 ug/L); carcinogenic PAHs: benzo(a)anthracene
(0.1 ug/L), chrysene (0.2 ug/L), benzo(b)fluoranthene (0.2 ug/L), benzo(a)pyrene (0.2 ug/L),
dibenzo(a,h)anthracene (0.3 ug/L), and indeno(l,2,3-cd)pyrene (0.4 ug/L); arsenic (50 ug/L); benzene (5 ug/L);
and PCP(1 ug/L).
- The goal of the source area extraction system is to remove oil-contaminated groundwater and NAPL from the
area of the waste pit and remove as much NAPL as possible.
- The goal of the in situ bioremediation and pump and treat system is to reduce PAH and PCP concentrations in
the upper aquifer to levels below remedial goals.
Results:
- As of December 1996, concentrations in many parts of the plume had declined to either remedial goals or
detection limits. However, there are areas of groundwater contamination in which levels of PAHs and PCP
remain near original levels.
- DO levels have been measured as an indication of the extent of influence on the intermediate injection system
and as an indicator for PAH and PCP in the groundwater.
- The source area treatment system had removed 37,570 pounds of PAHs from the groundwater from 1992 to
1996.
Cost:
- Estimated costs for treatment through 1996 were $5,628,600 ($3,010,000 in capital and $2,618,600 in O&M),
which correspond to $374 per 1,000 gallons of groundwater extracted and $150 per pound of contaminant
removed. These costs do not account for the volume of groundwater treated or the mass removed through in
situ bioremediation. No estimates have been made for these two items.
Description:
The Libby Montana site has been used as a lumber mill and wood-treating facility since 1946. From 1946 to
1969, the site used various compounds, including creosote and PCP, hi their wood-treating operations. The mill
was operated by the St. Regis Company until 1985 when it was purchased by Champion International. In 1979,
homeowners detected a creosote odor in their well water. EPA monitoring in 1981 confirmed groundwater
contamination from the Libby site. The site was placed on the NPL in September 1983 and a ROD was signed in
December 1988.
The remedial strategy at this site was to address the source area by removing NAPL and to stimulate
bioremediation in the down-gradient upper aquifer plume. The three components to the aquifer remedial system
are a source area extraction system, intermediate injection system, and boundary injection system. As of
December 1996, concentrations hi many parts of the plume had declined to either remedial goals or detection
limits. However, there are areas of groundwater contamination in which levels of PAHs and PCP remain near
original levels. The site operators believe that no additional modifications could be made to improve the
system's performance or to reduce the time required to remediate the intermediate injection area.
Ill
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Libby Groundwater Superfund Site
SITE INFORMATION
Identifying Information:
Libby Groundwater Site
Libby, Montana
CERCLIS#: MTD980502736
ROD Date: December 30,1988
ESD Date: (1) September 4,1993, (2) January
22,1997
BackgroumL!jL2]
Treatment Application:
Type of Action: Remedial
Period of operation: September 1991 -
Ongoing (Performance data collected through
December 1996)
Quantity of material treated during
application: As of December 31,1996, 15.1
million gallons of groundwater were treated.
Historical Activity that Generated
Contamination at the Site: Lumber Mill -
Wood Preserving
Corresponding SIC Code: 2491 (Wood
Preserving - Creosote & Pentachlorophenol)
Waste Management Practice That
Contributed to Contamination: Improper
storage and disposal of wood preserving
products.
Location: Libby, Montana
Operations:
• The Libby, Montana site has been used as a
lumber mill and wood-treating facility since
1946. From 1946 to 1969, the site used
various compounds, including creosote and
pentachlorophenol (PCP) in their wood-
treating facility. The mill was operated by
the St. Regis Company until 1985 when it
was purchased by Champion International.
• The area around the facility includes
residential areas and businesses. The site
is bordered on the west by Flower Creek, on
the east by Libby Creek, and on the north by
the Kootenai River. The contaminated soil
and source area is within the confines of the
site. The groundwater contamination
extends into the City of Libby, located less
than 1,000 feet downgradient.
In 1979, homeowners detected a creosote
odor in their well water. EPA monitoring in
1981 confirmed groundwater contamination
from the Libby site.
The site was placed on the National
Priorities List (NPL) on September 8, 1983.
Source removal activities included the
excavation of approximately 67,000 cubic
yards of soil and debris. The rock and
debris were physically separated from the
soils, resulting in 45,000 cubic yards of
contaminated soils, which were treated
through land treatment.
A Phase IV remedial investigation/feasibility
study (RI/FS) report was prepared by
Woodward-Clyde Consultants in July 1986.
Field operations were conducted from May
1985 to February 1986. The September
1986 Record of Decision (ROD) provided an
alternate water supply to residents whose
wells were contaminated through a Buy
Water Plan. In a second ROD in December
1988, final remedial actions for
contaminated groundwater included pump
and treat and in situ bioremediation.
An Explanation of Significant Differences
(ESD) was issued in 1997 to change the
remedial goals to reflect new information on
exposure levels for several contaminants of
concern.
EPA
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Libby Groundwater Superfund Site
SITE INFORMATION (CONT.)
Background (Cont.l
Regulatory Context:
• In 1983, St. Regis and EPA signed an
Administrative Order on Consent for the
company to study contamination at the site.
Champion International purchased the St.
Regis Corporation in 1985 and has taken
over its obligations to the Order. In 1989,
EPA and Champion signed a Consent
Decree in which the company agreed to pay
the U.S. Government past and future
oversight costs and to complete
implementation of the remedial action. A
construction completion approval was
obtained in late 1993.
• A ROD for the Upper Aquifer operable unit
was signed on December 30, 1988.
Site Logistics/Contacts
• Site activities are conducted under
provisions of the Comprehensive
Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments
and Reauthorization Act of 1986 (SARA)
§121, and the National Contingency Plan
(NCP), 40 CFR 300.
Remedy Selection:
The remedy for contaminated groundwater
includes in situ bioremediation and groundwater
extraction and treatment via an oil water
separator and an above-ground fixed-film
bioreactor.
Site Lead: PRP
Oversight: EPA
Remedial Project Manager:
Jim Harris*
U.S. EPA - Region 8
301 S. Park Dr.
P.O. Box 10096
Helena, MT 59626
(406) 441-1150 ext. 260
State Contact:
Neil Marsh
Montana Department of Environmental Quality
(MDEQ)
Remediation Division
(406)444-0487
* Indicates primary contacts.
Treatment System Design:
Woodward-Clyde Consultants
4582 South Ulster Street
Stanford Place 3, Suite 1000
Denver, CO 80237
Facility Operations:
Ralph Heinert*
Champion International Corporation
Corporate Environmental
Highway 2 South
P.O. Box 1590
Libby, MT 59923
(406) 293-6238 phone
(406) 293-5415 fax
EPA
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Libby Groundwater Superfund Site
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the
Treatment System: Groundwater
Contaminant Characterization
Primary Contaminant Groups: Polycyclic
aromatic hydrocarbon (PAH) compounds and
pentachlorophenol (PCP).
The contaminants described here are limited to
those found in the Upper Aquifer.
Contamination has migrated to the Lower
Aquifer but remedial actions are limited to the
Upper Aquifer. Remediation of the Lower
Aquifer was addressed in a 1993 ESD.
• The primary contaminants of concern
include PAH compounds (both carcinogenic
and noncarcinogenic) and PCP (Appendix A
presents the levels of contaminants of
concern detected in private groundwater
wells in 1986).
• Maximum concentrations found during the
1986 RI/FS were: pentachlorophenol (3,200
ug/L), acenaphthene (100 ug/L), napthalene
(500 ug/L), acenapthyiene (200 ug/L), and
benzo(a)anthracene (1 ug/L) [1].
The areal extent of the contaminated
groundwater plume was estimated in 1992
to be 1.2 miles long and cover
approximately 232 acres [3]. The
contaminant plume was estimated to
contain as much as 2.2 million gallons of
free product [4]. Figures 1 through 3 depict
the areal extent of groundwater
contamination from carcinogenic PAHs,
noncarcinogenic PAHs and PCP,
respectively, as measured in July 1992.
Nonaqueous phase liquids (NAPLs), both
dense and light, have been consistently
observed in monitoring wells in the source
area and downgradient of the intermediate
injection system. In a 1997 report, site
engineers stated that the NAPL in the upper
aquifer appears to exist as free-phase
product in small pools, trapped between
strata or as a residual phase trapped in pore
spaces [4].
Matrix Characteristics Affecting Treatment Costs or Performance
Hydrogeology:
Groundwater is present at this site in a highly transmissive aquifer, and is encountered at approximately
10 to 20 feet below land surface (bis). Groundwater flows through the alluvial valley formed by the
Kootenai River. To identify different zones of contamination, the aquifer has been divided into two
primary units. The upper aquifer, also referred to as the upper saturated unit, is formed of highly
transmissive deposits of unconsolidated, interbedded gravel, sand, and clay. The upper aquifer extends
to 60 to 70 feet bis and flows from the site north and northwest toward the City of Libby. The deposits
are predominantly clean to silty gravel and sand with occasional interbedded layers approximately 2 to
10 feet thick containing clay and silt. From 70 to 110 feet bis, the deposits consist of silt and clay with
interbedded layers of clean to silty gravel and sand. These deposits form a discontinuous aquitard,
separating the upper aquifer from the lower. The lower aquifer is found at approximately 110 feet bis
and extends to approximately 160 to 180 feet bis. The lower aquifer is composed of clean to silty gravel
and sand layers, interbedded with clay and silt layers, extending to bedrock [2].
EPA
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Libby Groundwater Superfund Site
MATJRIX DESCRIPTION (CONT.)
// """c--.y/ /,-•
4// toTs/^/C
LEGEND
<0.68hT..'
— — APPROXIMATE EXTENT OF TOTAL CARCINOGENIC PAH ',' ',,-. i^-,
COMPOUNDS IN THE UPPER AQUIFER > 0.88 ug/L (CAL '/ s5aJ5?L59^| *
DETECTION LIMIT). | pf^4
Figure 1. Distribution of Total Carcinogenic PAHs in Upper Aquifer (July 1992) [2]
EPA
U.S. Environmental Protection Agency
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Libby Groundwater Superfund Site
MATRIX DESCRIPTION (CONT.)
"c^y/ ^-"-'//"~--^f'/// ,-,// ~"^i. //" "••••• ."7'f '\ , . f L
l'^lK^^^fe^i§^/ W-A
£ ^--B»Jif —*^4^ /^^'Hf <=> \ ^
JJ • .6005 \ ( -^>'/ 1018 //'$ } U
^l Wfe^ji )isjC_rn ^\
N
0 300 600
SCALE IN FEET
^(Siyr^
LEGEND
TfTr^FTl^lf^f
-J^«¥^e V
ioi4^to3.0..v.,.|-/
i , K«riT • '
— APPROXINIATE EXTENT OF TOTAL NON-CARCINOGENIC PAH
COMPOUNDS IN THE UPPER AQUIFER -»4 ug/L
302;
Figure 2. Distribution of Total Noncarcinogenic PAHs in Upper Aquifer (July 1992) [2]
EPA
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Libby Groundwater Superfund Site
MATRIX DESCRIPTION (CoNT.)
:^//lf// l/^L'// "^^\ \j
^.^^>^/^»/ '^---- J
^£^--;^ t,/^M'^$, \ . '.i i
' 107I ^tfj*''-' s;^wp//:«57v;;^ra^-/ ;V ^
X/ 1026~t ^ ^ '" i"'"'^^ ^221* /^ if" '- •' ' ^
—* i.6005 \< ""--.r'Ciois -'A-7
1fl7Q * «ni« i !. I ^"r •< ••/>.. j — i 1
LEGEND
— — APPROXIMATE EXTENT OF PCP IN THE UPPER AQUIFER
>0.5 ug/L. (CAL DETECTION LIMIT)
stfZm APPROXIMATE AREA EXCEEDING PCP CONCENTRATION
^^^ OF1.05mg/L.
Figure 3. Distribution of PCP in .Upper Aquifer (July 1992) [2]
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Libby Groundwater Superfund Site
MATRIX DESCRIPTION (CONT.)
Matrix Characteristics Affecting Treatment Costs or Performance fConU
Table 1 presents technical aquifer information.
Table 1. Technical Aquifer Information
Unit Name
Upper Aquifer
Lower Aquifer
Thickness
(ft)
15-70
160-180
Conductivity
(ft/day)
100-1,000
100
Average
Velocity
(ft/day)
3-10
<3
Flow Direction
North-Northwest
North-Northwest
Source: [5,6]
TREATMENT SYSTEM DESCRIPTION
PflmapJceatinent Technology
In situ bioremediation and pump and treat (P&T)
consisting of an oil/water separator followed by
two fixed-film bioreactors in series
SvsterrLDescription and Operation
Supplemental Treatment Technology
None
Tables 2 and 3 provide technical information about the extraction and injection wells used at this site,
respectively.
Table 2. Extraction Well Data
Well Name
9006
9008
Note: Average system
Unit Name
Deeper portion of
Upper Aquifer
Deeper portion of
Upper Aquifer
extraction rate was 6.6 gpm
Depth (ft)
67-73
76
(currently operating
Design Yield
(gal/min)
16
6
at 16 gpm).
Source: [5,6]
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Libby Groundwater Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation (Cont.)
Tabled. Injection Well Data
Well Name
Intermediate Injection System
3004-1
3004-2
3007-1
3007-3
9500
9501
Boundary Injection System
9001
9502-1
9502-2
9503-1
9503-2
Unit Name
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Upper Aquifer
Depth (ft)
18-21
34-37
20-23
42-45
45-65
18-38
25-40
20-40
46-56
19-39
45-55
Design
Injection Rate
(gal/min)
27
2
3
1
10
50
67
50
50
50
15
Source: [5,6]
System Description
• The remedial strategy at this site was to
address the source area by removing NAPL
and to stimulate bioremediation in the
downgradient upper aquifer plume. An
Applicable or Relevant and Appropriate
Requirements (ARAR) waiver has been
granted for the lower aquifer due to the
technical impracticability of remediating
NAPLs and the low likelihood that the lower
aquifer poses a risk to human health and
the environment [6].
There are three components to the upper
aquifer remedial system at the Libby site:
source area extraction system, intermediate
injection system, and boundary injection
system shown in Figure 4. The components
were constructed in phases beginning in late
1989 and were finished in early 1993 [4,5].
The source area extraction and treatment
system consists of extraction wells, an
oil/water separator, nutrient addition, and
two fixed-film bioreactors, operated in
series. The system extracts heavily
contaminated groundwater from the upper
aquifer, separates the NAPL from the water
in the oil/water separator, adds nutrients to
the extracted groundwater, and then treats
the dissolved-phase contamination in
bioreactors. From the bioreactors, the
effluent is discharged to infiltration trenches.
The objective of the system is to remove
NAPL from the upper aquifer to improve the
performance of the naturally occurring in
situ biodegradation downgradient of the
source area [5].
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Libby Groundwater Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
GROUNDWATER \
FLOW DIRECTION
APPROXIMATE
EXTENT OF
CONTAMINATION
RMEDIATE
NJECTION
SYSTEM
LAND
TREATMENT
UNIT
F n F M n
e
55
EXTRACTION WELL
INJECTION WELL/WELL NEST
EXISTING MONITORING WELL/WELL NEST <
PLUGGED AND ABANDONED BORING
APPROXIMATE WELL AND BORING LOCATION
ISO 3OO
SCALE IN FEET
THE LOCATION OF THE BIOREACTOR BUILDING.
COO THE BOUNDARY INJECTION BUILDING. AND THE
FOLLOWING WELL LOCATIONS' SHOWN ON MAP
ARE APPROXIMATE:
3O38 3O4O 3042 65O3 9OO7
3O39 3O41 3O43 9OO6
Figure 4. Locations of Remedial System Components [6]
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Libby Groundwater Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation (ConU
Five extraction wells were installed at
different depths in the upper aquifer in the
source area. Four of these wells were
completed as two-well pairs, with one well of
each pair screened in the shallow portion of
the upper aquifer and the other well
screened in the lower portion. This well
design allows flexibility in selecting the best
pumping scenario. As of 1998, only two
wells remain in service, extracting
approximately 16 gpm.
The extracted groundwater flows to a
10,000-gallon oil/water separator where
floating and sinking NAPLs are removed.
The tank is eight feet in diameter and 26
feet long. From the separator, the process
water flows to the bioreactors. Liquid
nutrients are added to the process water
before it enters the bioreactors. Oxygen is
added through an aeration system within
each bioreactor [5].
The bioreactor units consist of two 10,000-
gallon tanks filled with a polyethylene
media. The process water from the
oil/water separator is heated in the first
bioreactor to 22° Celsius to stimulate
biological activity. The polyethylene media
is designed to provide surface area on
which the biofilm forms. Contaminants are
adsorbed onto the biofilm where they
become a food source for the microbes.
Byproducts of aerobic biodegradation are
carbon dioxide, water, and additional
biomass [5].
The first reactor reduces the concentrations
in the process water by 70 to 80 percent.
The process water then flows to the second
tank where most of the remaining
contaminants are removed. The elevated
level of oxygen in the bioreactors re-
oxygenates the effluent before it is
discharged to the infiltration trenches [5].
The in situ bioremediation system consists
of two gravity injection systems-the
intermediate and boundary injection
systems-through which oxygen and
nutrients are added to the Upper Aquifer.
The intermediate injection system consists
of six wells, and the boundary injection
system consists of three wells [4, 5].
The source of water for injection is an on-
site pond. Hydrogen peroxide was initially
used to oxygenate the water and was added
at a rate of 100 mg/L. However, when the
boundary system was installed in early
1993, alternative oxygenation methods were
investigated to lower costs of operations.
As a result, a U-Tube oxygenator system
and a bubbleless aeration system were
installed. Based on its success, this method
also replaced the hydrogen peroxide
method used in the intermediate injection
system [5].
Nutrients (nitrogen and phosphorous) are
added to the water for the intermediate
injection system to maintain levels of 2.4
mg/L and 1 mg/L, respectively in the
injection water [5]. During the design of the
boundary system, it was found that
sufficient levels of nutrients already were
present in the groundwater, originating from
natural sources or migrating from the
intermediate system wells; therefore, the
addition of nutrients was not necessary for
this system.
The monitoring plan at this site requires
sampling of the extraction well system, the
in situ system, and the monitoring wells for
the intermediate and boundary systems.
Water levels, concentrations of
contaminants, and geochemical parameters,
such as temperature, dissolved oxygen
levels, and nutrients, are monitored.
Twenty-three wells are sampled annually for
PAHs and PCP. Twenty-one wells are
monitored monthly for dissolved oxygen and
water levels [5].
There is an on-site laboratory that performs
wet chemistry. Most PAH and PCP
analyses are performed on site, but some
contaminant analyses are performed by an
off-site commercial laboratory for quality
assurance purposes [5]. Dissolved oxygen
(DO) analyses are performed in the field
with direct reading instruments.
EPA
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Libby Groundwater Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
SjrjtejnJLescription and Operation fConU
Year
1992
1993
1994
1995
1996
Total
Source:
Total Volume
Pumped
(gal)
4,355,000
2,620,000
1,100,000
3,470,000
3,520,000
15,065,000
[2, 6, 7, 8, 9]
System Operation
• Quantity of groundwater pumped from
aquifer from 1992 to 1996:
Average Pump
Rate
(gal/min)
8.4
5.6
2.2
6.6
7.5
6.1
The source area extraction system has
operated nearly continuously since
operations began. There were some
interruptions to system operations because
of several failures of the Protec pump, such
as drive-rod breakage and gear box failure.
The percentage of time that the system has
operated ranges from 89 to 100 [6].
The intermediate and boundary injection
systems have been in near-continuous
operation from mid-1990 through December
1996 [2, 6, 7, 8,9].
The intermediate injection system operates
at an average rate of 70 gpm, and nutrients
are added to the injection water to maintain
levels of approximately 2.4 mg/L nitrogen
and 1 mg/L phosphorus. The level of DO is
maintained at approximately 40 mg/L
[2,6,7,8,9].
The boundary injection system operates at
an average rate of 232 gpm; no nutrients
are added. Dissolved oxygen levels are
maintained at approximately 51 mg/L
[2,6,7,8,9].
PAH removal occurs primarily in the first
fixed film bioreactor; PCP removal occurs
primarily in the second reactor [4].
During 1992, a study was performed to
optimize the temperature of the bioreactors
to lower the cost of their operation. The
results indicated that there was no
difference in performance between 22° and
30° Celsius. The temperature in the
bioreactors was lowered to 22° Celsius [6]. .
During the summers of 1992 and 1993,
efforts were made to expand the capacity of
the source area treatment system. Two
different fixed film bioreactors were tested
and both were successful in expanding the
treatment capacity. However, it was
determined that it was more cost-effective
to improve the efficiency of the system by
improving the performance of the oil/water
separator. Consequently, the tests on the
growth bioreactors were stopped, and
several studies were undertaken to improve
the performance of the separator. [6]
Studies to improve the performance of the
oil/water separator included adding
dissolved-air flotation and flocculation, and
lengthening retention times. The studies
showed that the performance of the
separator improved when droplet size
increased. A positive-displacement,
progressive-cavity pump was installed,
which increased NAPL droplet size by
reducing the extent of shearing produced by
the pump [6].
A review of the monitoring data from the
intermediate injection system wells in 1992
revealed a negative correlation between DO
levels and concentrations of PCP and
PAHs. On this basis, samples taken from
intermediate system wells from 1993
onward were analyzed for DO, and not PCP
and PAHs. If DO levels change
significantly, samples will be analyzed for
PCP and PAHs to directly measure the
change in groundwater quality [6].
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
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Llbby Groundwater Superfund Site
TREATMENT] SYSTEM DESCRIPTION (CONT.)
System Description and Operation (ConU
In May 1993, the hydrogen peroxide
injection system for the intermediate
injection system was replaced with a
bubbleless aeration system. The bubbleless
aeration system was pilot-tested over the
previous year to measure its cost and
performance. The site engineer determined
that a cost savings could be achieved,
without a loss in performance [6].
In 1996, three of the four original source
area extraction wells were abandoned
because they were no longer removing
NAPL. In December 1996, a fifth well was
installed to increase the removal of NAPL
from the source area groundwater [6].
During 1996, the facility operator tested a
Protec pump in one extraction well to
evaluate the pump's ability to reduce
emulsification of NAPL, and improve the
performance of the oil/water separator. The
original pump operated at 3,450 rpm, a
speed at which free product was being
emulsified and resisted gravity separation.
The Protec pump, operating at 350 rpm,
significantly reduces emulsification in the
well [7]. The Protec pump, however, has
not been able to operate for extended
periods of time without malfunctions.
According to the RPM, a Phase II design
report for the upper aquifer was submitted in
April 1997 and a Technical Impracticability
(Tl) report is currently being prepared. At
this time, no "additional groundwater
treatment activities are anticipated" [11].
Operating Parameters Affecting Treatment Cost or Performance
The major operating parameter affecting cost or performance for this technology is the pumping rate.
Table 4 presents the average pumping rate and other performance parameters.
Table 4. Performance Parameters
- ^ - ::;; ,:,s|arajiiB|ejfe*c^; ; -*:u
Average Pump Rate
Performance Standard
(Effluent)
Performance Standard
(Effluent)
Remedial Goals (Aquifer)
bi, ^'::'-^', , -iiJaloe- -v ^. - ^7,,
6.6 gpm
Non-carcinogenic PAH Compounds
Napthalene
Acenaphthene
Fluorene
Anthracene
Pyrene
Fluoranthene
1,460 ug/l
2,1 00 ug/l
1,460 ug/l
11, 000 ug/l
1,1 00 ug/l
1,460 ug/l
Carcinogenic PAH Compounds
Benzo(a) anthracene
Chrysene
Benzo(b)fluoranthene
§enzo(a)pyrene
Dibenzo(a,h)anthracene
lndeno(1 ,2,3-cd)pyrene
Arsenic
Benzene
Pentachlorophenol
Same as above
0.1 ug/l
0.2 ug/l
0.2 ug/l
0.2 ug/l
0.3 ug/l
0.4 ug/l
50 ug/l
5 ug/l
1 ug/l
Source: [6]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
123
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r
Libby Groundwater Superfund Site
TREATMENT SYSTEM DESCRIPTION (CONT.)
Timeline
Table 5 presents a timeline for this remedial project.
Table 5. Project Timeline
Start Data , End Date
Activity
7/87
4/88
Pilot scale test for in situ bioremediation conducted
12/88
ROD signed
1/90
1/91
Demonstration program for in situ bioremediation conducted
1/90
8/91
Phase I Remedial Design conducted
1991
Remedial construction performed
2/91
Operations for source area extraction system begun
1996
Three wells abandoned; one new well installed; change in pump speed tested
1997
ESD signed; remedial goals revised
Source: [2,4,6]
TREATMENT SYSTEM PERFORMANCE
CleanupGpalslStandards [11
• The remedial goals were revised in the 1997
ESD to reflect a recent risk assessment and
updated MCLs. Table 4 presents the revised
goals.
Jfffoment Performance Goals T61
Additional Information on Goals [4]
• The cleanup goals for this site were originally
established in the December 1988 ROD
based on achieving a 10'5 risk level in the
groundwater. At that time, the limit set for
total noncarcinogenic PAHs was 400 ng/L,
and 40 ng/L for total carcinogenic PAHs.
• The goal of the source area extraction
system is to remove oil-contaminated
groundwater and NAPL from the area of the
waste pit and remove as much NAPL as
possible.
performance Data Assessment
The goal of the in situ bioremediation and
P&T system is to reduce PAH and PCP
concentrations in the upper aquifer to levels
below remedial goals.
Total PAHs include napthalene, acenapthylene,
acenapthene, fluorene, phenanthrene,
anthracene, fluoranthene, pyrene,
benzo(g,h,i)perylene, benzo(a)anthracene,
chrysene, benzo(b)fluoranthene,
benzo(k)fluoranthene, benzo(a)pyrene,
dlbenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene.
• As of December 1996, concentrations in
many parts of the plume had declined to
either remedial levels or detection limits.
However, there are areas of groundwater
EPA
contamination in which levels of PAHs and
PCP remain near original levels.
As discussed in System Operation, DO
levels have been monitored to evaluate the
extent of the influence of the intermediate
injection system and as an indicator
measure for PAH and PCP levels in the
groundwater. Background levels for DO at
this site range from 3.0 mg/L to 4.2 mg/L
(DO levels in contaminated groundwater are
typically less than 1 mg/L). Decreases in
U.S. Environmental Protection Agency
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Technology Innovation Office
124
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Libby Groundwater Superfund Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment fCont.)
DO levels indicate that increased
contaminant concentrations are depleting
available DO faster than it can be
supplemented from the injection system.
• Figure 5 shows DO concentrations in three
of the 18 wells that are used to monitor the
progress of the intermediate injection
system. These three wells are located
within 600 feet of the injection system,
which is the limit of the influence of the
intermediate injection wells. In these and
five other wells, PAH and PCP
concentrations have declined to either
remedial goals or below detection limits.
The spikes and troughs seen in these
graphs do not necessarily directly
correspond with a decline or increase in
PAH or PCP levels. According to the site
engineers, an order of magnitude change in
DO concentrations is required before a
"significant" change in groundwater quality
would be indicated [4, 6].
In the remaining 11 wells used to monitor
the performance of the intermediate
injection system, PAH and PCP
concentrations have shown little decline
from original levels [4].
• Figure 6 shows trends in PCP, PAH, and
DO levels in one of the wells used to
monitor the progress of the boundary
Performance Data Completeness F41
injection system. DO levels in this well and
nine other boundary injection system
monitoring wells have increased. In most
wells, a corresponding decrease in PAH and
PCP concentrations, such as that shown in
Figure 6, has been observed. By
September 1996, PCP and PAH
concentrations were not detected in seven
and eight of the 10 wells, respectively.
However, because the remedial goals for
PCP and carcinogenic PAHs are below the
on-site laboratory detection limit, data from
the on-site laboratory do not indicate
whether remedial goals have been met in
these wells [4].
According to the Phase II Design Report,
migration in the PAH and PCP plumes had
ceased by the end of 1996. The site
engineers believe that an equilibrium has
been reached between the advection,
dispersion, and degradation of PAHs and
PCP in the aquifer and the rate of
dissolution of those compounds in the
source areas [4].
The source area treatment system removed
a total of 37,570 pounds of PAHs from the
groundwater from 1992 to 1996. Of the two
components of the treatment system, the
oil/water separator removed a total of
23,200 pounds of PAHs, while the
bioreactor degraded 14,370 pounds [4].
A total of 42 monitoring wells are sampled
annually for PAHs and PCP.
Performance Data Quality T41
Bimonthly DO analyses are performed in
each of the monitoring wells. Samples are
taken from the influent and effluent of the
treatment system on a weekly basis and
analyzed for PAHs, PCP, and DO.
Analyses for PAHs and PCP are performed using modified EPA Methods 8100 and 8040, respectively.
The on-site laboratory was used for the majority of analyses required for this site.
The QA/QC program used throughout the remedial action met the EPA and the State of Montana
requirements. All monitoring is performed using EPA-approved methods, and the site contact did not
note any exceptions to the QA/QC protocols.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
125
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Libby Groundwater Superfund Site
TREATMENT SYSTEM PERFORMANCE (CONT.)
WELL 3016.1
'* 20
ie
I"
& 12
f 10
4
2
0
120"
18-
7 16-
f 14
| 12
< 10
I
* 40
35'
.
*.*•
WELL 3026.1
WELL 3032.1
:
-,
F/gure 5. Dissolved Oxygen Concentrations in Three Intermediate Monitoring Wells [6]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
126
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Libby Groundwater Superfund Site
TREATMENT SYSTEM RERFQRMANCE (CONT.)
500
400"
300
200
100
0
i i i i i i i i m i
> 900
eoo-4.
700-.
i 600
.
coo
400
300
200
100 •
o
£70
55
SO
f55
' 50
7T 48
D) 40
f 35
| 30
O 25
& 20'
° 15-
10
5
0
: *
"
p--*--«« «_ / i ;
/ 'v V V /
NO » NOT DETECTED
F/gfure 6. Graphs of PCP, Total PAH, and Dissolved Oxygen in One Boundary Monitoring Well 3042.2 [6]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
127
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Libby Groundwater Superfund Site
TREATMENT SYSTEM COST
Procurement Process
Champion International Corporation, in cooperation with EPA Region 8, leads the remedial activities for
the Libby Site. Woodward-Clyde Consultants provides design and oversight services for Champion.
The remedial activities at the site are part of a performance evaluation of groundwater biological
treatment processes (bioremediation) being conducted by the U.S. EPA National Risk Management
Research Laboratory (Scott Huling) and Utah State University.
.Cost Analysis [10]
• All costs for design, construction and operation of the treatment system at this site are borne by
Champion International Corporation.
CapitaLCosts
Operating Costs
Remedial Construction
Engineering and Site Services
Construction
Sample Analysis/Data
Management
Drilling and Sampling
Equipment/Supplies
Total Remedial Construction
$1,050,000
$700,000
$210,000
$140,000
$910,000
$3,010,000
1989-92 Operations and Services $980,000
1993 Operations $437,000
1994 Operations $363,400
1995 Operations $418,200
1996 Operations $420,000
Total Operations 1989 - 1996 $2,618,600
Average Annual Operating $327,300
Expenses
Other Costs
Remedial Design
$350,000
Cost Data Quality
Estimated capital and operating and maintenance cost data were available from Champion International.
Limited information on the items included in the total project costs was provided. To date, including
RI/FS and EPA oversight, over $14 million was spent in total for this site.
OBSERVATIONS AND LESSONS LEARNED
Estimated costs incurred through 1996 were
$5,628,600 ($3,010,000 in capital costs and
$2,618,600 in operating and maintenance
costs). This corresponds to $374 per 1,000
gallons treated and $150 per pound of
contaminant removed. These costs do not
account for the volume of groundwater treated
or the mass removed through in situ
bioremediation. No estimates have been made
of the mass of PAHs and PCP that have been
degraded through in situ bioremediation [10].
The selection of the Protec pump for the source
area extraction wells had an impact on the
overall cost of the system. Each pump cost
approximately $10,000, and two were
purchased. The pumps cannot be run for
extended periods of time without malfunctions,
which has interrupted the operation of the
source area treatment system. Prior to the use
of Protec pumps, standard centrifugal pumps
were used at this site. The use of standard
centrifugal pumps with rotation speeds of 3450
rpm did not let the oil settle in the extraction
wells because droplets were too small [4].
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
128
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Libby Groundwater Superfuncf Site
OBSERVATIONS AND LESSONS LEARNED (CONTINUED)
The adoption of a U-Tube oxygenator system
and a bubbleless aeration system for the two
injection systems proved to be a cost-effective
alteration to the systems [4].
To avoid clogging with biological growth, two
infiltration trenches were constructed and used
alternately, allowing one to dry while the other
was in use [4].
According to the 1997 Phase II Design report,
the NAPL pools in the upper aquifer will
dissolve slowly. The time required to dissolve a
NAPL pool depends on the contaminant.
According to the Design Report, it would take
270 years to dissolve the PCP, 75 years for
naphthalene, and 110,000 years for
benzo(a)pyrene [4].
The site operators believe that no additional
modifications could be made to improve the
systems performance and to reduce the time
required to remediate the intermediate injection
area. The individual systems are operating as
expected [4].
REFERENCES
1. Superfund Record of Decision for Libbv
Groundwater Contamination Site. U.S. EPA,
December 30,1988.
2. 1992 Annual Operations Report For The
Upper Aquifer. Woodward-Clyde Consultants,
February 28,1993.
3. Performance Evaluation of Bioremediation: In
situ Bioremediation of the Upper Aquifer.
Utah Water Research Laboratory, Utah State
University, May 1997, unpublished.
4. Upper Aquifer Phase II Design Assessment
Report Libbv Superfund Site. Woodward-
Clyde Consultants, April 1997.
5. Remedial Design Report Upper Aquifer
Operable Unit Libbv Groundwater Site Libbv.
Montana. Woodward-Clyde Consultants,
August 1991.
Analysis Preparation
6. 1996 Annual Operations Report For The Upper
Aquifer. Woodward-Clyde Consultants,
February 1997.
7. 1995 Annual Operations Report For The Upper
Aquifer. Woodward-Clyde Consultants,
February 1996.
8. 1993 Annual Operations Report For The Upper
Aquifer. Woodward-Clyde Consultants,
February 28,1994.
9. 1994 Annual Operations Report For The Upper
Aquifer. Woodward-Clyde Consultants,
February 28,1995.
10. Remedial Cost Report provided by Champion
International Corporation, June 1997.
11. Comments on draft report from Jim Harris,
EPARPM, July 1, 1998.
12. Comments on draft report from Ralph Heinert,
Champion International Corp., July 8,1998.
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
129
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Libby Groundwater Superfund Site
Appendix A
Contaminants Detected in Private Groundwater Wells As Reported in the 1986 ROD
Arsenic
Zinc
1,400
Copper
160
Chromium
10
Lead
30
Nickel
29
Pentachlorophenoi (PCP)
3,200
Napthalene
500
Acenapthylene
200
Acenapthene
100
Fluorene
48
Phenanthrene
212
Anthracene
15
Fluoranthene
93
Pyrene
44
Chrysene
Benzo(a)anthracene
1-methyl napthalene
250
2-methyl napthalene
43
Benzene
20
Toluene
51
Carcinogenic PAHs
93
EPA
U.S. Environmental Protection Agency
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Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Moffett Federal Airfield,
Mountain View, California
131
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Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Moffett Federal Airfield,
Mountain View, California
Site Name:
Moffett Federal Airfield
Location:
Mountain View, California
Contaminants:
Chlorinated solvents
- Maximum concentrations
detected during 1991 investigations
include TCE (20,000 ug/L) and
PCE (500 ug/L)
Period of Operation:
Status: Ongoing
Report covers: 4/96 - 7/97
Cleanup Type:
Voluntary pilot-scale study
Vendor:
Tim Mower
Tetra Tech EM Inc.
1099 18th Street, Suite 1960
Denver, CO 80202
(303)312-8874
Chuck Reeter
Naval Facilities Engineering
Service Center
1100 23rd Ave., Code 411
PortHueneme, CA 93043-4370
(805)982-4991
EPA Point of Contact:
Lynn Suer
EPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-2396
Technology:
Permeable Reactive Barrier (PRB)
- The PRB is a funnel-and-gate iron
treatment wall system consisting of
2 sheet pile walls, permeable zones
up- and down-gradient of the wall,
and the reactive zone
- The PRB is composed of 100%
granular iron, is 6 ft thick, 10 ft
wide, and 18 ft high beginning 5 ft
below ground surface
- Average flow rate through the
wall was estimated as 0.5 ft/day
(alternate estimates also provided)
Cleanup Authority:
Not applicable
Navy Point of Contact:
Stephen Chao (Navy Project
Manager)
Bldg. 210
Department of the Navy
EFA-West
900 Commodore Drive
San Bruno, Ca 94066
Waste Source:
Leaking underground and
aboveground storage tanks, waste
sumps; on-site migration of
contaminants from Silicon Valley
plume
Purpose/Significance of
Application:
Use of PRB technology in a pilot
study for treatment of chlorinated
solvents; included extensive
sampling conducted at locations
within the wall.
Type/Quantity of Media Treated:
Groundwater
- 0.284 million gallons treated as of July 1997
- DNAPL suspected hi groundwater on site
- Groundwater is found at 5 ft bgs
- Extraction wells are located in 5 hydrogeologic units, which include
upward hydraulic gradients
- Hydraulic conductivity ranges from 0.3 to 400 ft/day
Regulatory Requirements/Cleanup Goals:
- The objectives of the pilot project are to (1) demonstrate and validate the PRB technology in remediating
groundwater contaminated with chlorinated hydrocarbons; (2) evaluate the long-term effectiveness of the
barrier from a hydraulic stand point; and (3) develop cost and performance data.
132
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Permeable Reactive Barrier to Treat
Contaminated Groundwater at the Moffett Federal Airfield,
Mountain View, California (continued)
Results:
- Data from sampling events in January, April, and July 1997 showed that chlorinated solvent concentrations
were being reduced as the groundwater moves through the reactive zone. For example, TCE concentrations
measured in upgradient wells during April 1997 were reduced to below the detection limit within the reactive
zone. PCE and 1.2-DCE also were reduced to below the detection limit within the reactive zone.
- A tracer test performed in July 1997 showed that flow patterns within the wall are complex, with some lateral
flow, and that flow velocities are lower than expected based on previous site characterization and modeling.
Cost:
- Actual costs for PRB use over one year at this site were $405,000 ($373,000 in capital and $32,000 in O&M),
which correspond to $1,400 per 1,000 gallons of groundwater treated.
Description:
Moffett Federal Airfield is a former Navy facility providing support, training, operation, and maintenance
associated with Navy aircraft. Aircraft engine repairs and aircraft maintenance have been performed on site for
many years. Contaminant identification and cleanup activities have been underway at Moffett since 1987.
Specific activities that contributed to the source at MFA included dry cleaning operations. The Navy and
Department of Defense Environmental Security Technology Certification Program (ESTCP) are funding this
PRB as a voluntary pilot study for treating a portion of a large plume that crosses the Moffett facility.
The PRB installed in 1986 is a funnel and gate iron treatment wall system. Components include two sheet pile
walls, permeability zones up- and down-gradient of the wall, and the reactive zone. Analytical data showed that
chlorinated solvent concentrations were being reduced as the groundwater moves through the reactive zone. A
final technology evaluation report for this pilot study was planned to be completed by August 1998. Proposals
are being presented to continue the sampling process annually or semi-anmially.
133
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Moffett Federal Airfield
SITE INFORMATION
Identifvina Information:
Moffett Federal Airfield
Mountain View, California
CERCLIS #: Not applicable
ROD Date: Not applicable
Treatment ADDlication:
Type of Action: Pilot Test
Period of operation: April 1996 - Ongoing
(Performance data collected through July 1997)
Quantity of material treated during
application: 284,000 gallons of groundwater
Historical Activity that Generated
Contamination at the Site: Service and
support for Navy aircraft
Corresponding SIC Code: 3728 (Aircraft parts
and Auxiliary Equipment)
Waste Management Practice That
Contributed to Contamination: Leaking
underground and aboveground storage tanks,
waste sumps; on-site migration of contaminants
from Silicon Valley plume
Location: Mountain View, California
Facility Operations [1, 2]:
• Moffett Federal Airfield (MFA) is a former
Navy facility providing support, training,
operation, and maintenance associated with
Navy aircraft. Aircraft engine repairs and
aircraft maintenance have been performed
on site for many years. Cleanup and
contaminant identification activities have
been underway at MFA since 1987.
• This report addresses a Permeable
Reactive Barrier (PRB) pilot study that, if
effective, will be scaled up to remediate a
large portion of the shallow aquifer at MFA.
Currently, the PRB intercepts and treats
contaminated groundwater immediately
downgradient of a single source area at
MFA. This site is complicated by the
presence of a large groundwater plume that
crosses MFA from off-site sources. The
Navy is working with the responsible parties
for the off-site sources to remediate the
groundwater contamination.
Remedial investigations were started in
August 1990 and completed in April 1991 by
International Technology Corporation and
Tetra Tech EM, Inc.
• Contaminants in the area of the PRB consist
primarily of chlorinated solvents. Specific
activities that contributed to the source at
MFA included dry cleaning operations.
• The Navy and Department of Defense
Environmental Security Technology
Certification Program (ESTCP) is funding
this PRB as a pilot study for treating a
portion of the large plume that crosses
MFA.
Remedial performance monitoring is being
conducted by Tetra Tech EM and the PRB
performance evaluation is being conducted
by Battelle Memorial Institute (Columbus
operations).
Regulatory Context:
The PRB was constructed as part of a voluntary
pilot-scale study to demonstrate the
effectiveness of the PRB for treating a
groundwater plume of chlorinated solvents.
Groundwater Remedy Selection:
An in situ PRB was selected for a pilot study at
this site.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
134
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Maffett Federal Airfield
SITE INFORMATION (CONT.)
Site Logistics/Contacts
Site Lead: U.S. Navy
Oversight: EPA
Treatment System Vendors:
Tim Mower*
Tetra Tech EM
1099 18th Street, Ste. 1960
Denver, CO 80202
303-312-8874
Chuck Reeter*
Naval Facilities Engineering Service Center
1100 23rd Ave., Code 411
Port Hueneme, CA 93043-4370
805-982-4991
indicates primary contacts
Remedial Project Manager:
Stephen Chao (Navy Project Manager)
Bldg. 210
Department of the Navy
EFA - West
900 Commodore Drive
San Bruno, CA 94066
EPA Contact:
Lynn Suer
EPA Region 9
75 Hawthorne Street
San Francisco, CA 94105
415-744-2396
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the
Treatment System: Groundwater
Contaminant Characterization 12.31
Primary Contaminant Groups: Halogenated
volatile organic compounds (VOCs)
• Contaminants detected near the location of
the treatment wall include perchloroethene
(PCE), trichloroethene (TCE), cis- and
frans-1,2-dichloroethene (1,2-DCE),
1,1-dichloroethene (1,1-DCE), and
1,1-dichloroethane (1,1-DCA). Historically,
1,2-DCE and TCE are the predominant
groundwater contaminants in the vicinity of
the PRB.
• Maximum contaminant concentrations
detected during 1991 investigations include
20,000 ug/L of TCE and 500 ug/L of PCE.
In June 1996, TCE levels of over 5,000 ug/L
were measured upgradient of the wall
location. This may indicate that the plume
originates from a continuous source.
Figure 1 is a contour map that depicts TCE
concentrations detected in February/March
1995. The 2,000 ug/L TCE contour line is
closest to the treatment wall location.
Dense nonaqueous phase liquid (DNAPL)
presence is likely because of elevated
concentrations detected in groundwater
samples and processes known to have
occurred at the facility. The maximum
concentration of TCE detected was near 2%
of its solubility limit.
In 1991, the TCE plume was estimated to
be over 10,000 feet long and 5,000 feet
wide. Contaminants have been detected to
a depth of 70 feet. The volume of the
contaminant plume was estimated to be
5.6 billion gallons in the remedial
investigation (Rl) report. The PRB at MFA
is treating a small part of this plume located
in a shallow aquifer immediately
downgradient of a source area.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
135
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MATRIX DESCRIPTION (CONT.)
Moffett Federal Airfield
Figure 1. TCE Concentration (fjg/L) (February/March 1995) [2]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
136
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Moffett Federal Airfield
MATlRix DESCRIPTION (CONT.)
Matrix Characteristics Affecting Treatment Costs or Performance 12]
Hydrogeology:
Five distinct hydrogeologic units have been identified beneath this site. Groundwater is found
approximately five feet below ground surface. MFA lies on a relatively flat depression, known as Santa
Clara Valley, present between the San Andreas and Hayward Faults. Regionally, the Santa Clara Valley
contains up to 1,500 feet of interbedded alluvial, fluvial, and estuarine deposits. These sediments
consist of varying combinations of clay, silt, sand, and gravel. Subsurface sediments have been divided
into the A, B, and C aquifers. Most contaminants at MFA are found within the A aquifer, which includes
two permeable zones. The PRB is designed to treat only those contaminants in the A1 unit.
Unit A1 Surficial
Sediments
Unit A2 Surficial
Sediments
Unit B1
Unit B2
Unite
Fluvial
Sediments
Fluvial
Sediments
Estuarine
Sediments
Fine- to coarse-grained material. Uppermost permeable zone, highly
contaminated. A discontinuous confining bed is present beneath this
unit. Upward hydraulic gradients are present between units A1 and
A2.
Fine- to coarse-grained material. Highly contaminated and having a
continuous 5- to 7-foot thick clay aquitard beneath. Upward hydraulic
gradients are present between the A and B aquifers.
Thin sand and gravel beds in a fine-grained matrix. Not
contaminated, highly conductive (similar to A aquifer).
Thin sand and gravel beds in a fine-grained matrix.
Fine to medium clayey and silty sand.
Tables 1 and 2 include technical aquifer information arid technical wall data, respectively.
Table 1. Technical Aquifer Information
Unit
A1
A2
B1
B2
C
Thickness
(ft)
25
40
45
15
>100
Conductivity
(ft/day)
1 -400
30 - 200
0.3 - 50
0.4 - 40
Not available
Average Velocity
(ft/day)
0.005 - 2
0.15-1
0.0014-0.22
0.0018-0.18
Not available
Flow
Direction
North
North
North
North
Not
available
Source: [2]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
137
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Moffett Federal Airfield
TREATMENT SYSTEM DESCRIPTION
Primary Treatment Technology
Permeable Reactive Barrier (PRB)
SyjjejnJBescrlption and Operation
Supplemental Treatment Technoloav
None
Table 2. Treatment Wall Data
Unit
Flow Control Zone
Continuous
Treatment Wall
Flow Control Zone
Flow-Through
Thickness
2 feet
6 feet
2 feet
Conductivity
(ft/day)
>1,000
1,000
>1,000
Material
Pea gravel
100%
Granular
iron
Pea gravel
Vertical
Thickness
18 feet
18 feet
18 feet
Source: [2,4]
System Description [2,3,4,7]
• The PRB is a passive, in situ treatment
technology that makes use of natural
groundwater flow to carry contaminants
through the reaction zone.
• The PRB, installed in 1996, is a funnel and
gate iron treatment wall system. The
components include two sheet pile walls,
permeability zones upgradient and
downgradient of the wall, and the reactive
zone. Table 2 provides technical wall data.
Figures 2 and 3 illustrate the layout and
dimensions of the PRB.
• Two sheet pile walls measuring 20 feet in
length extend at a 90° angle from the wall
(perpendicular to groundwater flow
direction). These walls act as a funnel to
force more of the contaminant plume
through the PRB.
• The PRB is composed of 100% granular
iron, has 6 feet of flow-through thickness, is
10 feet wide, and 18 feet high beginning 5
feet below ground surface. The flow control
zones upgradient and downgradient of the
wall are composed of pea gravel and have 2
feet of flow-through thickness.
The PRB extends down through Unit A1, but
is not keyed into the low conductivity unit
comprised of clayey fine sand to silty clay
that is found at a depth of approximately 23
to 25 feet below ground surface. This
material is not classified as an aquitard;
however, it is believed to inhibit
contaminant transport to Unit A2. The iron
filings begin at a depth of 5 feet below
ground surface, which corresponds with the
groundwater table. Native soil was
backfilled above this depth. Two feet of
concrete and bentonite were placed below
the iron to prevent downward migration of
contaminants.
The PRB utilizes reactive zero-valent iron to
dehalogenate the chlorinated compounds to
chloride and ethylene.
The actual residence time in the treatment
zone for the dechlorination and reduction
reactions has been estimated to be
approximately 96 hours based on the
highest concentration scenario. A minimal
residence time of 48 hours is required to
degrade contaminants to meet cleanup
goals.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
138
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Moffett Federal Airfield
TREATMENT SYSTEM DESCRIPTION (CONT.)
2'
21
Downgradient Wells
(AQUIFER)
•
WIC-9
WIC-10
W1C-1Z
10'
WKMl
PIC-31
PIC-32
2'
WW-18{A-D)
WW-l(A-D)
WW-S
WW-9
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TREATMENT SYSTEM DESCRIPTION (CONT.)
Moffett Federal Airfield
0 50 100 150 200
Funnel Walls
Al Aquifcr.WfiU
Aouifer Well
Figures. Site Plan [2]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
140
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TREATMENT, SYSTEM DESCRIPTION (CONT.)
Moffett Federal Airfield
System Description and Operation Source (Cont.)
• Twenty-eight multi-level monitoring wells
are located within the treatment zone.
These wells are placed at 1 to 2 foot
intervals to monitor contaminant
concentration reduction through the wall.
Four wells are located both upgradient and
downgradient of the treatment zone to
monitor influent and effluent concentrations.
System Operation [1, 2, 7-10]
Quantity of groundwater treated:
Time Frame
1996-1997
Approximate Volume
Treated
284,000 gallons
Based on average groundwater velocity of 0.5 ft/day, and
dimensions of 10 feet wide and 18 feet deep [2].
Since April 1996, the PRB has been 100%
operational.
There have been no maintenance
requirements for the treatment wall to date.
The reactive media may need to be
replaced if the wall becomes clogged or
ineffective. The monitoring plan requires
monitoring of the wall for plugging and
continued effectiveness. Sampling in
December 1997 indicated no significant
clogging.
Monitoring wells and research sampling
points are sampled quarterly, for
piezometric head to evaluate groundwater
velocity and flow direction through the
treatment wall.
Operating Parameters Affecting Treatment Cost or Performance
Table 3 presents operating parameters affecting cost and performance for this technology.
Table 3: Performance Parameters
,l?";'"'pSam,^;';:> &
Average Flow Rate through
Treatment Wall
Required Residence Time
tj/<',f. - ~ Value I5i' jfe
• 0.5 ft/day
[Estimate used for calculation
purposes [9]]
48 hours
Source: [1]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
141
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TREATMENT SYSTEM DESCRIPTION (CONT.)
Moffett Federal Airfield
Timeline
Table 4 presents a timeline for this pilot-scale project.
Start Date
4/95
8/95
1/96
4/96
6/96
9/96
1/97
4/97
7/97
10/97
End Date
8/95
1/96
—
5/96
...
...
„_
.
—
Activity '-:' - * ;', '/ " ' "\
Lab tests and column studies performed
Treatment wall designed
Procurement process begun
3-week construction period
First sampling event conducted
Second sampling event conducted
Third sampling event conducted
Fourth samplinq event conducted
Fifth sampling event conducted (in conjunction with tracer test)
Sixth samolina event conducted
Source: [1]
TREATMENT SYSTEM PERFORMANCE
Treatment Performance Goals Ml
The objectives of the pilot project are to: (1) demonstrate and validate the PRB technology in
remediating groundwater contaminated with chlorinated hydrocarbons; (2) evaluate the long-term
effectiveness of the barrier from a hydraulic standpoint; and (3) develop cost and performance data [7].
Performance Data Assessment F3. 61
Data from sampling events in January,
April, and July 1997 showed that chlorinated
VOC concentrations were being reduced as
the groundwater moves through the reactive
zone. For example, TCE concentrations
measured in upgradient wells during April
1997 were reduced to below the detection
limit within the reactive zone. PCE and
1,2-DCE were also reduced to below the
detection limit within the reactive zone.
Figure 4 shows that c/s-1,2-DCE and TCE
concentrations decrease as the groundwater
flows through the PRB. An average of the
January 1997 and April 1997 data at
specific intervals through the wall was used
to generate this figure. TCE concentrations
in the upgradient wells are near 1,000 ug/L;
at 4 feet into the PRB, TCE concentrations
are approximately 1 ug/L. Cis-1,2-DCE
concentrations begin near 200 ug/L
upgradient and decrease to less than 10
ug/L by the 4-foot interval.
Figure 5 presents mass flux data calculated
for the January, April, and July sampling
events. This figure indicates that mass
removed by the PRB has increased from
.007 Ibs/day to .0086 Ibs/day over the three
sampling events. TCE and c/s-1,2-DCE
concentrations were used for this calculation
as they account for most of the total
contaminant mass entering the PRB.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
142
TlO3.WP6Y1222-02.Stf
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§
Concentration (ug/L)
m
o'
CD
I'Sa
m •< =±
5: -n O
*§§
I
CO
CO
I
f
I
1
1
I
-A
JO
CO
53
Mass Flux (Ibs/day)
31
!
8
CD
I
1
5-
3
t
I
1
I
i
5
-------
Moffett Federal Airfield
TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment (Cont.)
A tracer test was performed in July 1997 to
assess performance of the PRB and to
determine groundwater flow direction and
velocity measurements within the treatment
wall. The tracer test was performed using
potassium bromide tracers. The results of
the tracer test indicated that some lateral
flow occurs within the wall and flow patterns
appear to be rather complex (not always in
straight lines). The flow patterns are
attributed to the differential compaction of
granular iron throughout the wall. Overall,
flow velocities were lower than expected
based on previous site characterization and
modeling.
Results from the tracer test indicate that
flow velocity through the cell ranges from
0.05 to 0.45 ft/day. According to the
contractor that performed the test (Battelle
Columbus Operations), these flow velocities
were much lower than were predicted by
site characterization and modeling (about 3
ft/day), water level measurements (up to 5
ft/day), and downhole velocity measurement
(1.1 to 6.1 ft/day) [6, 7].
Cores of in situ iron were collected in
December 1997 and analyzed for evidence
of precipitates and corrosion materials that
may reduce hydraulic and remedial
effectiveness of the barrier. Microbial
analysis of cored material also was
conducted to assess presence of iron
oxidizing or sulfate reducing bacteria [7].
Pprfnrmannp Data Comnleteness Ml
Seventy-two monitoring wells are sampled
quarterly. After one year of operation, the
monitoring schedule may be adjusted if
needed. The large number of wells are
sampled for research purposes. According
to Battelle, this number of wells exceeds the
typical protocol necessary to demonstrate
that the PRB is functioning properly and
meeting treatment goals.
Data from the January, April and July 1997
quarterly sampling events were available for
this report. Additionally, a tracer test study
was performed in July and also available for
this report.
In Figure 4, 2 ug/L is the detection limit.
When data was reported as below detection
limits, half the detection limit (1 ug/L) was
used in the future.
Pprfnrmanrp Data Qualitv
The QA/QC program used throughout the remedial action met the EPA and the State of California
requirements. All monitoring was performed using EPA-approved methods, Method 353.1, Method N-
601, SW-846 Method 8240, SW-846 Method 8020. Laboratory reports for the April 1997 sampling event
indicated that detection limits were unacceptably high for the A1 aquifer zone wells and upgradient pea
gravel wells due to excessive sampling dilution. The laboratory was asked to reanalyze samples.
However, because the holding time had elapsed, the affected wells were resampled in July 1997.
The Navy is the lead for this site. MFA is responsible for on-site activities and oversight. EPA views the
research activity as a means of remediating for a portion of the plume.
Cost Analysis
All costs for design, construction, and operation of the treatment system at this site are borne by the
Navy and DoD.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
144
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TREATMENT SYSTEM PERFORMANCE (CONT.)
Moffett Federal Airfield
Capital Costs
Remedial Construction
System Installation $323,000
Iron $50,000
Total Remedial Construction $373,000
Operating Costs
Monitoring/Analytical $32,000a
"First annual monitoring and analytical
contract
Cost Data Quality
Actual capital and operating and maintenance cost data are available from the Navy contact for this site.
OBSERVATIONS AND LESSONS LEARNED
The cost for groundwater remediation at this
site over one year was approximately
$405,000 ($373,000 in capital costs and
$32,000 in operating costs), corresponding
to a unit cost of $1,400 per 1,000 gallons of
groundwater treated.
Based on sampling data from the January,
April, and July sampling events,
concentrations of PCE, TCE, and 1,2-DCE
are being reduced as groundwater passes
through the reactive zone.
Data from monitoring points within the iron
show that, by the fourth foot of iron,
contaminant concentrations were reduced
below detection limits.
Mass flux was calculated from the quarterly
data and an estimate of groundwater
velocity from the tracer test conducted in
July. Mass flux data have increased over
the three sampling events indicating an
increase in influent concentrations, while
treatment goals continue to be met.
ESTCP is sponsoring performance
monitoring and cost data collection for
technology certification and validation.
Performance sampling is scheduled to
continue on an annual basis for at least two
more years. The final technology
evaluation report is planned to be
completed by August 1998. Proposals are
being presented to continue the sampling
process annually or semiannually.
REFERENCES
1. Draft Performance Monitoring Plan. Battelle
Columbus Operations, Cleveland, Ohio,
September 16, 1996.
2. Draft Operable Unit 4 Feasibility Study
Report. PRC Environmental Management,
Inc., Denver, Colorado, August 3,1992.
3. April 1997 Monitoring Report for the Pilot
Permeable Barrier at Moffett Federal
Airfield. Battelle, September 1997.
4. Phone Conversations with Deidre O'Dwyer,
June 21, 1997.
5. Phone Conversations with Tim Mower,
Tetra Tech EM Inc., May 28,1997.
6. Field Tracer Application to Evaluate the
Hydraulic Performance of the Pilot-Scale
Permeable Barrier at Moffett Federal
Airfield. Battelle, October 1997.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
145
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Moffett Federal Airfield
REFERENCES (CONT.)
7. Permeable Reactive Wall Remediation of
Chlorinated Hyrdocarbons in Groundwater
at Moffett Federal Airfield. Mountain View.
California. IBC Proceedings, January 1998.
8. Comments on draft report from Chuck
Reeter, NFRSC, July 8,1998.
Analysis Prenaratlon
9. Comments on draft report from Michael Gill,
Region IX RPM, July 17, 1998.
10. Comments on draft report from Tim Mower,
TetraTech EM Inc., July 17, 1998.
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
146
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Dual Auger Rotary Steam Stripping
at Pinellas Northeast Site,
Largo, Florida
147
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Dual Auger Rotary Steam Stripping
at Pinellas Northeast Site,
Largo, Florida
Site Name:
Pinellas STAR Center
Northeast Site
Location:
Largo, Florida
Contaminants:
- Chlorinated solvents and
volatiles - nonhalogenated
1,1-dichloroethane, 1,1-DCE,
benzene, ethylbenzene, 1,2-DCE,
methylene, chloride, toluene,
TCE, tetrachloroethene, vinyl
chloride, total xylenes, and
chloromethane
- Concentrations ranging from
500-5,000 ppm
- DNAPL suspected to occur as an
immiscible phase
Period of Operation:
December 1996 through April 1997
Cleanup Type:
Demonstration (ITRD Technology
Demonstration)
Vendor:
In-Situ Fixation, Inc. (ISF)
Chandler, Arizona
Additional Contacts:
David Ingle
DOE/GJO Environmental
Restoration Program Manager
(813)541-8943
Technology:
In Situ Air and Steam Stripping
- ISF dual auger system consists of
a Caterpillar 245D trackhoe
modified to operate two, 35-ft
long, hollow kelly bars with 5-ft
diameter augers
- Air and/or steam injected
through hollow kelly bars while
augers drill into subsurface, to
liberate VOCs
- Catalytic oxidation unit and acid-
gas scrubber were used to treat
the extracted VOCs
- 48 treatment holes drilled to a
depth of approximately 32 feet
- Technology focused on treating
saturated silty sands (below the
water table) contaminated with
high concentrations of VOCs
(500-5,000 ppm)
Cleanup Authority:
RCRA
Regulatory Point of Contact:
EPA Region 4 and State:
Florida Department of
Environmental Protection
Waste Source:
Leakage of solvents from
drum/container Storage
Purpose/Significance of
Application:
Demonstration of in situ air
stripping technology used to
supplement an ongoing system of
pump and treat with air stripping
Type/Quantity of Media Treated:
Soil and Groundwater
- Water table present approximately 3-4 feet below ground surface
- Soils consist of saturated beach-type silty sands with permeabilities
ranging between 10"3 to 10'5 cm/s
- Approximately 2,000 yd3 of soil treated
Regulatory Requirements/Cleanup Goals:
- The objective of this demonstration was to evaluate the performance of the ISF dual auger system in treating
contaminated soil and groundwater.
148
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Dual Auger Rotary Steam Stripping
at Pinellas Northeast Site,
Largo, Florida (continued)
Results:
- Demonstrated ability to remove large amounts of contaminants from soil and groundwater in a treatment
column .
- Removed an average of 77% of the VOCs in the groundwater and soil, and reduced the maximum
contaminant concentrations by an average of 71%
- Treatment of over 2,000 yd3 of soil and groundwater and the removal of approximately 1,200 pounds of
VOCs
Cost:
Total cost of remediation project was $981,251, including:
- Preproject operation visit - $2,400
- Mobilization and preparatory work - $95,000
- Monitoring, sampling, testing, and analysis - $59,000
- Physical treatment - $773,651 (equipment, labor, supplies and materials, and fuel)
- Disposal - $200 (hydraulic oil)
- Demobilization-$51,000
Description:
The Pinellas STAR Center operated from 1956 to 1994, manufacturing neutron generators and other electronic
and mechanical components for nuclear weapons under contract to the U.S. Department of Energy (DOE) and its
predecessor agencies. The Northeast Site is associated with the location of a former waste solvent staging and
storage area. In the late 1950s to the late 1960s an existing swampy area at the site was used to dispose drums of
waste and construction debris.
A field demonstration using a dual auger rotary steam stripping technology was conducted at the site from
December 1996 through April 1997. The demonstration was part of a program at the Pinellas STAR Center to
evaluate several innovative remediation technologies that could enhance the cost or performance of the existing
pump and treat system. In the demonstration, air and/or steam was injected through hollow kellys while the
augers drill into the subsurface, liberating VOC contamination during the churning and mixing of the soil. This
study identified operational issues, such as mechanical problems, catalyst overheating, and fugitive emissions
that required system adjustments and operational changes. These issues slowed the progress of the remediation
effort, but the system was overall very effective in liberating large quantities of VOCs from the site soil and
groundwater. During the 3-month operating period, 48 auger holes were drilled to a depth of approximately 32 ft
below land surface, resulting in treatment of approximately 2,000 yd3 of the planned 10,000 yd3 treatment
volume. Overall, approximately 1,200 Ibs of VOCs were removed from the soil and groundwater in the holes
treated in this project.
The cost of this remediation project was $981,251, with most of the costs being equipment operating costs. The
operational costs of the ISF system ranged from $50/yd3 to $400/yd3 of treated soil and groundwater, or about
$300/lb to $500/lb of contaminant removed. The ISF system was able to meet many of the performance
evaluation criteria; however, the off-gas treatment capacity of the catalytic oxidation unit along with initial
operational problems slowed the system's expected treatment rates for the site.
149
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•I 1. SUMMARY
From December 1996 through April 1997, the DOE's Innovative Treatment Remediation Demonstration
(ITRD) Program monitored the remediation performance of a dual auger rotary steam stripping
technology deployed at the Pinellas STAR Center Northeast Site in Largo, Florida. The system allows in
situ treatment of contaminated soil and ground water through the injection of air and/or steam into the
subsurface. The objective of this remediation effort was to accelerate the cleanup of a portion of the site
that consists of shallow, saturated soil and ground water contaminated with high concentrations (500-
5000 ppm) of volatile organic compounds (VOCs). The rotary steam stripping system used during this
remediation was developed and operated by In-Situ Fixation, Inc. (ISF), from Chandler, Arizona.
The ISF dual auger system consists of a Caterpillar 245D trackhoe that has been modified to operate two
vertical, 35-ft long, hollow kelly bars with 5-ft diameter augers. Air and/or steam is injected through the
hollow kellys while the augers drill into the subsurface, liberating VOC contamination during the churning
and mixing of the soil. A large shroud covers the auger hole to capture the VOCs removed by this
process for treatment. A catalytic oxidation unit and acid-gas scrubber were used to treat the extracted
VOCs in this application at Pinellas.
The project provided adequate analytical and operational data to evaluate the performance of the dual
auger rotary steam stripping technology. A Treatment Efficiency Characterization (TEC) Study was
initially conducted to identify system operational capabilities and issues over the range of contaminant
mixtures and concentrations in the planned treatment area. This study identified operational issues, such
as mechanical problems, catalyst overheating, and fugitive emissions that required system adjustments
and operational changes. These issues slowed the progress of the remediation effort, but the system
was overall very effective in liberating large quantities of VOCs from the site soil and ground water. It was
observed early in the project that a major limiting factor in the efficiency of the system in the areas of
highest contaminant concentration was the off-gas treatment capacity of the catalytic oxidation unit.
During the 3-month operating period, 48 auger holes were drilled to a depth of approximately 32 ft below
land surface, resulting in treatment of approximately 2,000 yd 3 of the planned 10,000 yd 3 treatment
volume. Many of the treatment holes had to be treated more slowly than expected to prevent the catalyst
in the catalytic oxidation unit from overheating from the large quantities of VOCs liberated by the augers.
The treatment rates at this site varied from 1 to 5 holes/day or about 5 to 30 yd/hr, depending on the level
of contamination encountered in each hole. Overall, approximately 1,200 Ib of VOCs were removed from
the soil and ground water in the holes treated in this project.
The cost of this remediation project was $981,251, with most of the costs being equipment operating
costs. The on-line time of the ISF system, including the dual augers, off-gas treatment, and the acid gas
scrubber components over the entire project averaged approximately 50%, while the on-line time of the
system approached 75% after the initial operational problems and issues were addressed and corrected.
Based on these on-line percentages, the operational costs of the ISF system at this site ranged from
$50/yd3 to $400/yd3 of treated soil and ground water, or about $300/lb to $500/lb of contaminant removed.
Based on the results of this demonstration, the ISF dual auger rotary steam stripping system is an
innovative technology capable of providing in situ treatment of VOC-contaminated soil and ground water.
During the application of this technology at the Pinellas STAR Center, the ISF system was able to meet
many of the performance evaluation criteria; however, the off-gas treatment capacity of the catalytic
oxidation unit along with the initial operational problems slowed the system's expected treatment rates for
the site. This prevented the system from achieving some of the performance objectives and treatment
volumes initially expected in this remediation.
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• 2. SITE INFORMATION
• Identifying Information
Facility.
OU/SWMU:
Location:
Regulatory Driver
Type of Action:
Technology:
Period of operation:
Quantity of saturated soil treated:
Pinellas STAR Center
Northeast Site
Largo, Pinellas County, Florida
RCRA
ITRD Remediation/Demonstration
Dual auger rotary steam stripping
12/96 to 4/30/97
2,048 yd3
•I Site Background
The Pinellas STAR Center occupies
approximately 100 acres in Pinellas
County, Florida, which is situated along
the west central coastline (Figure 1). The
plant site is centrally located within the
county; it is bordered on the north by a
light industrial area, to the south and east
by arterial roads, and to the west by
railroad tracks. The topographic elevation
of the Pinellas STAR Center site varies
only slightly, ranging from 16 ft mean sea
level (MSL) in the southeastern corner to
20 ft MSL in the western portion of the
site. Pinellas County has a subtropical
climate with abundant rainfall, particularly
during the summer months.
The Northeast Site includes the East Pond
and is located in the northeastern portion
of the Pinellas STAR Center site. The
Northeast Site is covered with introduced
landscaping grass and contains no
permanent buildings. The site contains
approximately 6 acres and is generally
flat, with slight elevation changes near the
pond. Access to the Northeast Site is
restricted and protected by fencing.
Site History
PINELLAS
PLANT
Gulf of
Mexico
Tampa Bay
tersburg
Figure 1. Pinellas STAR Center location.
The Pinellas STAR Center operated from 1956 to 1994, manufacturing neutron generators and other
electronic and mechanical components for nuclear weapons under contract to the U.S. Department of
Energy (DOE) and its predecessor agencies (SIC Code 9631 A-Department of Energy Activities).
The Northeast Site is associated with the location of a former waste solvent staging and storage area.
From the late 1950s to the late 1960s, before construction of the East Pond, an existing swampy area at
the site was used to dispose drums of waste and construction debris. The East Pond was excavated in
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1968 as a borrow pit. In 1986, an expansion of the East Pond was initiated to create additional storm
water retention capacity. Excavation activities ceased when contamination was detected directly west of
the East Pond.
The Northeast Site was identified as a Solid Waste Management Unit (SWMU) in a Resource
Conservation and Recovery Act (RCRA) Facility Assessment (RFA) 1 conducted by EPA Region IV.
Subsequently, a RCRA Facility Investigation (RFI)2 was completed and approved in compliance with the
facility's Hazardous and Solid Waste Amendments of 1984 (HSWA) permit.3
An Interim Corrective Measures (ICM) Study4A 6 was developed and submitted to EPA for approval. EPA
issued final approval of the ICM in October 1991, and an interim ground water recovery system for the
Northeast Site was installed and commenced operation in January 1992. The ICM system now consists
of seven ground water recovery wells equipped with pneumatic recovery pumps that transfer ground
water for temporary storage in a holding tank before being pumped to a ground water treatment system.
Hi Release Characteristics
The Pinellas STAR Center's Northeast Site consists of a shallow ground water aquifer contaminated with
a variety of VOCs, including chlorinated solvents such as trichloroethene (TCE), methylene chloride,
dichloroethene (DCE), and vinyl chloride. The primary management practice that contributed to
contamination was the storage of drums/containers. Because the site was used in the 1950s and 1960s
for staging and burying construction debris and drums, some of which contained solvents, contamination
at the Northeast Site is believed to be the result of leakage of solvents or resins from those drums. A
recent debris removal activity at the site confirmed the presence of multiple buried drums, many of which
were empty but contained solvent residue. The ongoing ICM system (pump and treat with air stripping)
continues to recover contaminants from the site and has been successful in preventing off-site migration
of VOCs.
H Site Contacts
Site management is provided by the DOE Grand Junction Office (DOE/GJO). The DOE/GJO
Environmental Restoration Program Manager is Mr. David Ingle [(813)-541-8943]. The Managing and
Operating contractor for this project at the Pinellas STAR Center was Lockheed Martin Specialty
Components, Inc. (LMSC). The technical contacts for the Rotary Steam Stripping Project are Mr. Barry
Rice [(813) 545-6036], and Mr. Mike Hightower, the ITRD Program Technical Coordinator at Sandia
National Laboratories [(505) 844-5499].
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3. MATRIX AND CONTAMINANT DESCRIPTION
The types of media processed by the rotary stripping system during this application were soil and ground
water (in situ). More specifically, this remediation technology focused on treating saturated silty sands
(i.e., below the water table) contaminated with high concentrations of VOCs (500 to 5000 ppm).
IH Site Geology/Hydrology
Based on analyses of soil borings,
details of well construction, and
environmental studies at the Pinellas
STAR Center, the thickness of the
surficial deposit below the site ranges
from 25 to 35 ft and is composed
primarily of silty sand. Soils consist
predominantly of saturated beach-type
silty sands with permeabilities ranging
between lO^to 10'5 cm/s. A few lenses
of more silty materials exist, although no
clay lenses occur in the soil being
treated. The top of the Hawthorn Group
(composed primarily of clay) at the
Pinellas STAR Center is encountered at
depths approximately 30 ft or greater
below ground surface. The thickness of
the Hawthorn Group ranges from 60 to
70 ft. The water table at the Pinellas
STAR Center is generally 3 to 4 ft below
the ground surface. Figure 2 shows the
primary geologic units at the site.
The ground water system at the Pinellas
STAR Center is composed of three
primary units: (1) an upper unit, the
surficial aquifer; (2) an intermediate
confining unit, the undifferentiated
portion of the Hawthorn Group; and
(3) a lower unit, the Floridan aquifer.
Undifferentiated sediments lie below the
surficial aquifer and above the Floridan
aquifer in Pinellas County. Because of
the low permeability of these sediments
in this region, these upper sediments
are not considered part of the
intermediate aquifer system and are
generally considered to be a confining
unit in the area of the Pinellas STAR Center.
Cross Section along Longitude 82*45'
Lot. 27-45'
Upper
Floridan
Aquifer
28W
--1001
--sty
: —0' Mean Sea Level
- -100-
+ a «**•"• *
* * . • « * "*•
-« * • ; - 4,
Lower
Florida n
Aquifer
Base of ,_ ,
Floridan Aquifer + -f-"
- Intergronular
(Cedar Keys
Evoponies
Formation)
LEGEND
Surficial Deposit3
UndCrferenlioted
Arcadia Formation,
Howthom Group
Tempo Member,
Arcadia formation.
Hawthorn Croup
Suwannoa Limestone
Qcakj Limestone
Avon Pork Limestone
Figure 2. Geologic section at the Pinellas STAR Center.
•I Nature and Extent of Contamination
The primary contaminant group that this technology was designed to treat in this application was
halogenated VOCs. Contamination at the Northeast Site is limited to ground water in the surficial aquifer.
Contaminants of concern (COCs) detected in Northeast Site ground water include 1,1-dichloroethane,
1,1 -DCE, benzene, ethylbenzene, 1,2-DCE (cis and trans isomers), methylene chloride, toluene, TCE,
tetrachloroethene, methyl tert-butyl ether, vinyl chloride, total xylenes, and chloromethane. The
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predominant contaminants detected at the site during performance of the demonstration were methyiene
chloride, 1,2-DCE, and TCE. Other VOCs detected in relatively high concentrations are toluene and vinyl
chloride.
Figure 3 shows a contour map of historical total VOC concentrations in the southern groundwater plume
at the Northeast Site as established by data collected prior to the rotary steam stripping project.
Operation of the rotary steam stripping system was proposed in the areas of highest contaminant
concentration (above 200-500 ppm). Table 1 summarizes the pretreatment concentrations of some of the
COCs within the planned treatment area.
CO
coa
8
a
00
Rotary steam stripping o
O treatment area
as planned
D
r
I 25'
East
Pond
Scale In Feet
depth
25'depth
Figure 3. Total VOC concentrations in ground water (in //g/L) in the
southern plume at the Northeast Site prior to the rotary steam stripping
project
Table 1. Pretreatment concentrations of COCs
Contaminant
Methyiene chloride
TCE
Toluene
ds-1,2-DCE
Vinyl chloride
Ground water
Max. cone.
(M9/L)
6,800.000
480,000
150,000
240,000
75,000
Avg. cone. (juglL)
751,000
40,300
18,600
32,800
10,000
Soil
Max. cone.
(M9/kg)*
720,000
1,200,000
660,000
12,000
1,700
Avg. cone, (^g/kg)*
31,100
35,700
20,600
1,100
90
' dry weight
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Based on the pretreatment sampling and
analyses and the volume of the treatment
area, Table 2 summarizes the estimated mass
of contaminants in the subsurface of the
planned treatment area for the rotary steam
stripping project. Sampling confirmed that the
zone of highest contaminant concentrations
generally lies in the western portion of the
treatment area between 20 ft and 30 ft below
the ground surface.
Table 2. Estimated contaminant mass in the planned
treatment area
Methylene chloride
TCE
Toluene and other VOCs
Total
6,000 Ib
1,900lb
1,100lb
9,000 Ib
•I Matrix and Contaminant Characteristics Affecting Treatment Cost or Performance
The Northeast Site includes an ongoing pump-and-treat system of seven ground water recovery wells
connected to an air stripper as an Interim Corrective Measure. Because of the high contaminant
concentrations of the dense chlorinated solvents in the southern plume at the Northeast Site, the
effectiveness of contaminant removal with a pump-and-treat system was a concern. Because of the high
volatility of the contaminants of concern and the generally high permeability of the contaminated soils, in-
situ stripping technologies were considered
likely candidates to help accelerate
remediation at the site. The potential benefit
of the rotary steam stripping technology was
its ability to quickly treat both the soil and
ground water, aggressively reducing the
source areas of high concentration to levels
more consistent with the rest of the site and
allowing the site to be more quickly and easily
remediated. Table 3 summarizes some of the
key matrix and contaminant characteristics at
the site as they relate to the performance of an
in situ rotary drilling/stripping technology.
The depth of contamination and soil
classification were important matrix para-
meters in considering the application of this
technology because shallow, loosely-
consolidated, granular soils support faster
penetration and enhance contaminant
removal. Moisture content was an important
matrix parameter because more energy can
be required to achieve contaminant removal in
saturated soils. Similarly, as TOG in soil
increases, VOCs are more strongly adsorbed
to soil, requiring more energy for volatilization.
In terms of contaminant parameters, the
volatility of the specific contaminants of
interest is obviously a key characteristic for
any type of stripping or heating technology.
The heat of combustion of contaminants,
including associated chemicals that are not the
primary COCs, is important in the selection
and design of the off-gas treatment
components of the sytem (as discussed in
Section 5).
Table 3. Key matrix and contaminant characteristics
Parameter
Value
Total depth of treatment 32 ft
Unsaturated thickness 3-5 ft
Saturated thickness 27 ft
Primary zone of contamination 20-30 ft
Soil classification
Clay content
Soil hydraulic conductivity
Moisture content
Total organic content
Contaminant volatility
Vapor pressure
Methylene chloride
TCE
Toluene
Contaminant heat of combustion
Methylene chloride
TCE
Toluene
Presence of DNAPLs
Silty sand
Low; approx. 5%
10-3to10'5
Saturated
Low
3790 mmHg@20°C
58 mmHg@20°C
22 mmHg@20°C
144 kcal/mol
226 kcal/mol
934 kcal/mol
Highly likely, as indicated
by the very high VOC
concentrations; believed
to occur as an immiscible
phase, rather than as a
single discrete "pool."
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•i 4. TECHNOLOGY DESCRIPTION
The technology evaluated in this field demonstration was rotary steam stripping for the in situ removal of
high concentrations of chlorinated organic solvents from soil and ground water. With this technology, a
mobile rotary drilling or augering system is used to inject hot air or steam into VOC-contaminated soils to
strip the contaminants from the soils and ground water. Several companies have developed mobile
treatment technologies based on this process. As stated previously, In-Situ Fixation of Chandler, Arizona,
developed and operated the rotary steam stripping equipment selected for this remediation effort.
•H Technology Description
The rotary steam stripping system is based on
rotary drilling technology.7i8 As shown in Figure
4, the system consists of a drill tower attached to
a mobile platform. In most applications, the drill
tower supports one or two drill blades or augers
designed to inject hot air or steam into the
subsurface soil as the drill blades or augers
penetrate below the ground surface. The
augers shear and mix the soil while the hot air or
steam is being injected, causing stripping and
thermal desorption of the organic contaminants
from the soil particles and volatilization of the
contaminants.9 The air, steam, and contaminant
vapors are carried to the surface by the injected
air and steam and are collected by a shroud
placed over the soil being treated. The shroud,
which is operated under a slight vacuum, rests
firmly on the ground so that the gases and
vapors released during subsurface treatment
are captured.
The contaminant vapors collected in the shroud
are sent to an above-ground processing unit for
treatment. Depending on the type and
concentration removed, contaminants can be
treated in various ways: condensation,
activated carbon adsorption, or thermal
destruction. The treated air and steam can be
reinjected for further soil treatment.
Figure 4. Photo of system.
These systems can be used to treat both the vadose and saturated soils in a batch process. To fully treat
an area, a grid of overlapping treatment zones is used. After one treatment zone is completed, the rotary
drilling system is moved to the next zone for treatment. Depending on the contaminant types and
concentrations, treatment rates of 4 to 20 yds/hr are possible with these systems. The number of passes
made up and down through the soil column by the drilling system is varied as needed to reduce the
contaminants to the desired treatment levels, thereby often obtaining contaminant removal efficiencies
ranging from 85% to 99%.10
A patent on certain aspects of the steam stripping technology exists, and the patent holder has pursued
what was interpreted to be patent infringements in the past. The exact details of this patent are not
known by the ITRD Program. According to In-Situ Fixation, Inc., no patent infringements occurred during
the Pinellas Project Anyone wishing to place contracts for the use of this technology should be aware of
the potential for patent-related issues.
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•I Technology Advantages
The treatment of VOC-contaminated soils and ground water using this type of system offers the following
advantages:
• treats the contaminated soils and ground water in situ without excavation while capturing air
emissions;
• provides thorough mixing and homogenization of the treated soil, resulting in effective contact between
the treatment agents and the contaminants;
• can operate in bedded soils of varying permeability, such as clays and sands;
• can operate in both vadose and saturated soils; and
• can be used to focus remediation at specific contaminated strata.
^1 Technology Limitations
This technology has the following limitations:
• Contaminant removal rates can be limited by the size and operational capabilities of the required off-
gas treatment system.
• Treatment is generally limited to contaminated soils less than 40 ft deep.
• Removal effectiveness and efficiency are dependent on the contaminant volatility and concentrations
and soil types.
• The intended treatment area must be cleared of underground obstructions.
In-Situ Fixation System Description
The ISF treatment system uses
a dual-auger steam injection
system. An integral drill tower
containing the dual augers and
collection shroud are mounted
on a Caterpillar trackhoe
chassis. The dual augers
(Figure 5) operate in a counter-
rotating mode to provide
balanced forces and stability of
the drill tower. The dual 5-ft-
diam augers overlap slightly,
providing a treatment area of
about 4.5 ft by 7.5 ft, or about
35 ft2. The current fixed-tower
design allows soil treatment to a
depth of about 35 ft. By being
mounted on the trackhoe
chassis, the drill tower and
augers can be moved easily
from one treatment zone to
another.
Figure 5. ISF dual auger bits and shroud.
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For application at the Northeast Site, the dual auger system was connected to a steam plant and air
compressor to provide both air and steam as the injection fluids for stripping the VOCs from the soil and
ground water. The shroud used to collect the stripped VOCs was connected to a catalytic oxidation
(CATOX) system (Figure 6) for destruction of the organic contaminants. The oxidation system was
connected to an acid-gas scrubber (Figure 7) to neutralize air emissions.
Figure 6. Off-gas treatment system
prior to completed assembly, showing
(from right to left) knock-out tank,
vacuum extraction unit, and CATOX.
Figure 7. Acid-gas scrubber tower
prior to assembly with quench unit
and CATOX.
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1H Treatment System Schematic and Operation
Figure 8 is a schematic of the ISF treatment system operated at the Pinellas STAR Center. The treatment
system process flow was as follows:
• The rotary steam stripping system was moved to the area to be treated, and the shroud was lowered
to the ground surface and placed under negative pressure.
• The rotating augers began penetration into the contaminated soil, continuously injecting either air
and/or steam through the drilling kelly bars into the contaminated soil and ground water.
• Depending on the contaminant removal rates and the amount of contaminants removed, the augers
made a series of passes up and down through the soil column.
• The contaminant vapors collected with the shroud were directed first to a water knockout tank and
then to a catalytic thermal oxidizer, where the VOCs were destroyed.
• The emissions from the catalytic oxidation system were passed through an acid-gas scrubber to
remove hydrochloric acid (generated during the destruction of the chlorinated VOCs) before discharge
into the atmosphere.
IDEPTH
IGAGE
/ 'I
/ TOWER
. . / SHROUD 1
[CAT245J/ S~
CH ~^> GROUND
SURFACE OFF
DUAL |
AUGERS 1
^
:\
r
"XPROCES
Llh
GAS
t
EACH 5'DIA
STEAM BOILER
— — 5000 LBS/HR
450 F 450 PSI
AIR COMPRESSOR
350 CFM 50PSIG
I LEL 1
£
S FLOW ^1 KO TANK 1 DUST ^r w|Bl
JE ~|1000GAL| HLIbH ^|lC
1
WASTE COMPUTER GC F
1/2 G/HR INSTRUMENT SHA<
ATM
HCI
SCRUBBER -
2000 ACFM
A
AIR INLET 60 «t
A
TRIABLE ^ T^
SPEED A. t
.OWERI ^ * <*.*.
00 CFM I ~ ~ Uf
1000
INF
ID
;K
k,
RHCL
^ 6
V
rox
JIT
CFM
>UT
OG/HR
VASTE
Figure 8. Process schematic.
Health and safety requirements for the operation of the system required continuous monitoring of the
following: the areas around the shroud for leakage of contaminant vapors, the concentration of
contaminants entering the catalytic thermal oxidation system, and the air emissions from the off-gas
treatment system. Figure 9 is an aerial view of the entire treatment system in operation at the Pinellas
STAR Center.
Hi Key Design Criteria
In situ anaerobic bioremediation is being considered as a potential remediation technology for the Pinellas
STAR Center's Northeast Site. The application of the rotary steam stripping technology at this site was
initiated to reduce the areas of very high levels of chlorinated solvents to levels more consistent with the
rest of the site and more compatible with bioremediation. This goal required the reduction of the identified
contaminants in the areas of high concentration from levels of 500 to 5000 ppm to levels of 100 to 200
ppm.
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Figure 9. Aerial view of the dual auger rotary steam stripping and off-gas treatment system.
Based on the areal extent and depth of the contamination at Pinellas, it was expected that approximately
10,000 cubic yards of soil could require treatment to a depth of approximately 30 ft. Based on the Florida
Department of Environmental Protection (FDEP) guidelines, the removal of these high concentrations of
VOCs from this volume of material would require air emission treatment. Initial estimates suggested that
the use of thermal treatment technologies would be more cost effective than other air emission control
devices, such as activated carbon. Based on the volume of contaminants to be treated, the largest easily
portable catalytic oxidation system was selected for use with the rotary steam system. Because the
VOCs being treated at the Northeast Site are predominately chlorinated solvents, an acid-gas scrubber
was also required to meet the FDEP's air discharge requirements.
1SF proposed a CATOX system design that would treat 60 Ib/hr of methylene chloride, the major site
contaminant. The scrubber capacity (60 Ib/hr HCI) was sized slightly larger to account for the presence of
TCE. It was anticipated that only in the most concentrated areas would the removal rate exceed 60 Ib/hr.
In these cases, process controls would be initiated to limit the VOC throughput to the off-gas destruction
system. The critical factors that determined the selection of the 60 Ib/hr capability of the off-gas
treatment system were (1) the combined cost of the scrubber, catalyst and CATOX; (2) the pretreatment
site characterization chemical data; and (3) the delivery schedule of the scrubber and CATOX.
Based on the site pretreatment chemical data, the presence of toluene was noted as significant in one
area of the site. As indicated in Section 3, toluene has a much higher (approx. 7 times) heat of
combustion than methylene chloride. If toluene occurred in even moderate amounts, its destruction
would release enough heat to limit off-gas throughput by causing catalyst overheating. It was difficult to
evaluate the extent of this potential problem prior to the remediation.
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!• Operating Parameters
The operating parameters (Table 4) of the rotary steam stripping system can be adjusted depending on
the effluent concentrations of the contaminants being treated, the capacity of the off-gas treatment
system, air emission requirements, and the type of soil being treated. Because the levels of contaminants
varied across the site to be treated, it was expected that different combinations of air/steam, injection
pressures, penetration rates, etc., would be varied to cost effectively reduce the contaminant
concentration levels across the site. For this application, two major areas of contaminated soil/ground
water treatment were addressed—one area had VOC concentration levels in excess of 5000 ppm, and
the other area had VOC concentration levels of about 500 ppm. Because of the flexibility of the treatment
system, each area was treated differently to optimize the treatment performance.
At the Northeast Site, treatment operations were generally conducted 8 to 10 hrs/day, 5 days/week. ISF
typically had five people involved in operations: a site supervisor, a health and safety officer [who doubled
as a sampler and gas chromatograph (GC) operator], a trackhoe operator, a boiler operator, and a
general laborer. Oversight by LMSC typically involved a project manager, and an individual from the
LMSC Industrial Hygiene/Safety Department routinely visited the site during operations.
Operation of the rotary steam stripping system was controlled and adjusted based on the VOC levels
coming out of the shroud, which were continuously monitored with an in-line flame ionization detector
(FID). Treatment parameters (depth, FID, process temperature, air injection rate, steam injection rate,
and process flow rate) were continuously monitored with a digital display, strip chart recorder, flowline
meters, and pressure gauges located throughout the system. A remote FID and depth display was
mounted in the CAT245 cab for the operator. The operator observed and used these data to adjust the
penetration rates and treatment times in each of the treatment holes. This continuous monitoring during
drilling reduced the chance of exceeding the catalyst temperature threshold in the CATOX system and
assisted in directing treatment to the appropriate horizons in each hole.
Table 4. Typical operating parameters
Parameter
System equipment base/mover
Stripping system
Support equipment
Treatment area per hole
Auger rotation rate
Auger penetration rate
Air injection rate/pressure
Steam injection capacity/ temperature
Vacuum on shroud
CATOX capacity/throughput
CATOX operating temperature
Value
Caterpillar 245D trackhoe
Dual counter-rotating, 5 ft-diam augers
Backhoe, welder, off-gas treatment system,
compressor, boiler, generator, parts trailer
35ft2
12 rpm
1 ft/min avg
200-300 scfm avg @ 125 psi
2,000-4,000 Ibs/hr @ 450° F @ 550 psi
5-10 in. water
60 Ib/hr (based on methylene chloride)
approx. 1000-1 100°F
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•I 5. ROTARY STEAM STRIPPING SYSTEM PERFORMANCE
ISF treated an area within the Pinellas STAR Center Northeast Site from January through April 1997. The
following sections of this report present a summary of the system's performance.
•I Remediation Objectives and Approach
The remediation was coordinated by LMSC, the DOE's site contractor for the Pinellas STAR Center, in
cooperation with the ITRD Program. The primary objective of the rotary steam stripping project was to
quickly remediate areas of high concentrations of contaminants within the designated treatment area of
the Northeast Site. Through the remediation of these areas of high concentration, the Northeast Site
would then have more moderate contaminant levels that could be more easily treated with a proposed in
situ bioremediation effort.
The approach to the remediation focused on four supporting objectives:
1. optimize system operating parameters through an initial Treatment Efficiency Characterization (TEC)
study,
2. evaluate overall system performance in treating VOC-contaminated soil and ground water,
3. evaluate system operation effects on the surrounding environment, and
4. quantify site-specific unit treatment costs.
H Performance Evaluation Criteria
Performance criteria considered in the evaluation of the rotary steam stripping technology included the
following:
• ability of the system to remove VOCs in the soil and ground water to a level of 100 to 200 ppm in an
approximate 10,000-yd3 treatment volume,
• recovery and treatment of volatilized contaminants to air emission levels specified in the FDEP's
Notice of Authorization 1°i11 to conduct the rotary steam stripping project,
• absence of fugitive hazardous emissions from the treatment system, and
• absence of migration of contaminants outside the treatment area.
The methods used to assess performance were:
1. To gain further insight into the rotary steam stripping technology and to establish efficient operating
parameters to remediate the treatment area, a TEC was conducted immediately after system setup.
2. To verify VOC removal and determine final contaminant levels, pre- and post-treatment soil and
ground water sampling and analyses were performed. The ITRD group established a sampling grid
(Figure 10) to characterize the planned treatment area and its perimeter.
3. To verify the level of recovery and treatment of volatilized contaminants, air samples were collected
daily during operations from the CATOX influent, the CATOX effluent, and the scrubber effluent.
4. To verify the absence of any fugitive emissions from around the treatment system, monitoring was
performed with a hand-held FID vapor analyzer during operations.
5. To verify the absence of migration of contaminants outside the treatment area, soil and ground water
sampling points were established around the treatment area perimeter, and monitoring wells around
the perimeter were sampled before and after treatment operations.
Cosf and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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RSS Treatment Grid
= sampling points ( 1 j = treatment column
Figure 10. Sampling grid with overlay of treatment holes.
•I Operational Summary
Mobilization Phase
Equipment and materials were transported to the Pinellas STAR Center's Northeast Site from
approximately September 25 through December 24, 1996. The original estimate for completion of
transport of equipment was mid-November, with a completion of assembly by the end of November.
Several issues resulted in the delay of completion of the mobilization phase untilJanuary 20, 1997. One
significant issue Was that an available CAT 245D trackhoe (this specific model was required to mate with
the ISF dual auger system components) rental unit was not able to be located in the southeastern United
States, necessitating the transport of one from Phoenix, Arizona:
After assembly, the drilling of two practice holes demonstrated that the dual-auger system was able to
penetrate the soils at the Northeast Site without any significant resistance and that the air and steam
injection through the soil and ground water, along with the resultant recovery of vapors, appeared to be
functioning as expected. However, hydraulic problems (a broken fitting and incorrectly connected
hydraulic lines) encountered on the first practice hole resulted in a one-week delay in beginning
operations. ' '"' ' '
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Treatment Efficiency Characterization Phase
A Treatment Efficiency Characterization (TEC) Study was conducted to identify system operational
capabilities and issues over the range of contaminant mixtures and concentrations in the treatment area.
The ITRD group chose three specific areas based on contaminant levels and characteristics. Figure 10
shows the locations of not only these areas, but also sampling points and later treatment holes. The 1 A,
B, and C holes were located in an area of very high VOC contamination in the ground water (up to
5,000,000 //g/L total VOCs). TEC No. 2 hole was located in an area of moderate VOC contamination in
the ground water (approx. 250,000 ^g/L total VOCs). The 3A, B, and C holes were located in an area
with the highest levels of total VOCs in the soil (approx. 400,000 //g/kg total VOCs).
The TEC phase began on January 21 and continued through February 11. During the treatment of these
areas, air only was injected into the 1A and 3A holes, air and steam was injected into the 1B and 3B
holes, and air was injected in the first pass then steam for the remaining passes for the 1C and 3C holes.
The results were monitored to develop optimal treatment settings for the rest of the treatment area.
Sampling of soil and ground water was performed before and after treatment of the TEC locations, and an
in-line FID was used during operations to collect continuous total VOC removal quantities. Several initial
operational issues with the system were identified during the TEC and are listed in Table 5.
Table 5. Operational issues and delays during the TEC
Issue
Result and extent of delay
Field GC was not operating properly for approx. 2
weeks, necessitating the use of the LMSC Analytical
Laboratory.
Destruction efficiency of the off-gas treatment system
dropped below the permit-required 90% destruction.
Because of efficiency problems of the off-gas treatment
system, operations were limited to treating one hole
and then ceasing operations until it was confirmed that
the off-gas treatment system was effectively destroying
the contaminant vapors in accordance with the air
emissions permit requirements.
Packing in the scrubber tower melted due to a loss of
cooling water caused by a plant-wide water shutoff.
Fugitive emissions were detected outside of the dual
auger system shroud. Some of the fugitive emissions
exceeded the Permissible Exposure Limits (PELs) in
the breathing zone for the project.
Automatic alarm shutdowns of the CATOX unit and the
vacuum extraction unit occurred when the mass of
VOCs being fed to the CATOX was large enough to
raise the temperature of the catalyst beyond its
operating limits.
During periods of recovery and treatment of large
masses of VOCs, the acid-gas scrubber was incapable
of controlling the pH of the air emissions.
Delayed receipt of analytical results at least 1 day.
Repaired CATOX unit and catalyst (2 days).
Resulted in the loss of approximately V* to 1 day of
operations after treating each hole.
Removed and replaced with new packing (2 days).
Variable extent; this continued to occur throughout the
project; however, the frequency of occurrence was
decreased by limiting the air injection rate, creating an
exclusion zone around the shroud and placing a large
sheet of plastic around the shroud to limit fugitive
emissions.
Variable extent; this problem continued to occur
throughout the project; however, it was limited by
increasing the catalyst's operating temperature limits
and implementing procedures to limit the mass of
VOCs being fed to the CATOX.
Variable extent; further inspection revealed an
undersized caustic-addition pump intake line. When
the size of the intake line was increased, the scrubber
was able to neutralize the air emissions at all times.
Cosf and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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At the end of the TEC phase, the following operational characteristics of the rotary steam stripping system
became apparent:
• The mass of VOCs (especially any VOC with a high heat of combustion) being fed to the CATOX had
to be limited; otherwise, the catalyst could be overheated.
• Catalyst overheating protection shutdowns frequently occurred when air and steam were being
injected. ,
• The dual-auger system was capable of removing more contaminants than the design capacity of the
off-gas treatment system.
• Fugitive emissions were able to escape outside the shroud and could exceed PELs.
• Because of the FDEP's air emissions limitations, timely and accurate gas sample analysis was
critical.
• Sampling of the TEC holes where only air injection was used (1A & 3A) showed mixed results, with
negative removal(i.e., contaminant redistribution) of VOCs in the soil and groundwater at 20 ft below
land surface (bis), and good removal of VOCs from the ground water at 30 ft bis.
• Sampling of the TEC holes where steam and air injection was used (1C, 2, 3B, 3C, & 4A-C) showed
generally better results, with more limited occurrences of redistribution of VOCs in the soil and
groundwater at 20 ft bis, and good removal of VOCs from the ground water at 30 ft bis.
Remediation Phase
As discussed in Section 3 and shown in Figure 3, the contaminants at the site in the area treated with the
dual-auger system were mainly between 16 and 30 feet below the surface. Additionally, the highest
levels of contamination occurred on the west end of the treatment area and decreased quickly to the
east. Because of these relative levels of contamination, it was decided to begin treatment in the areas of
highest contaminant concentration. From Figure 10, this included treatment holes 1-5. After beginning
treatment of production hole No. 1 on February 12, the off-gas treatment system continued to experience
problems with catalyst high temperature shut-downs. On February 18, the dual auger system sheared
bolts that attach the kelly bars to the drive unit and was inoperable until February 25. Further problems
with the off-gas treatment system resulted in only three holes being treated during this phase in February.
(Two holes were treated in the TEC phase during February.)
March operations in the western portion of the treatment area continued to have problems with fugitive
emissions and catalyst high-temperature shutdowns until March 4, when LMSC personnel decided that
the rotary steam stripping system was not able to operate effectively at this elevated level of
contamination, and no further knowledge of the technology's application at this site was being gained .
On March 5, the system was moved to the central portion of the treatment area, where contamination
levels were significantly lower. This included treatment holes 6-33. Holes 6-11 were quickly treated in two
days. On March 7, 'the system was unable to back out of hole No. 11 due to a failed drive chain in the
main gearbox. Repairs of the system lasted through March 18. Operations resumed on March 19, after
which 26 holes were treated in 6 days, and progressively lower levels of contamination were being
encountered as treatment progressed eastward.
On March 24, after finishing hole number 33, the system was moved back to the area of higher contaminant
concentration because LMSC personnel felt that the knowledge and experience of system operations on-
site had improved to a point where effective treatment could be accomplished in the higher concentration
areas. The system remained in this area for the remainder of the remediation phase, treating holes 34-41.
Because of the higher contaminant concentrations in this area, several passes were required in each hole,
and operations were slowed to keep from overheating the catalyst. On March 27, clay buildup on the dual
auger's cutting teeth was slowing penetration rates enough that the clay had to be removed, and it was
discovered that the boiler had to be descaled. Operations once again resumed on March 31 and
continued through April 2, at which time the funding for the time-and-materials phase of the subcontract
was depleted, and the project was terminated.
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H System Performance and Treatment Results
Contaminant removal by the dual auger system from each of the treatment holes was monitored with an
FID located on the dual auger shroud. This provided a continuous display of the amount of contaminants
being removed by the system. It also allowed the operator to concentrate treatment in each borehole in
the zone of highest contaminant concentration. The FID was calibrated with a GC throughout the
remediation so that, along with the continuous monitoring of the air and steam flow rate through the
shroud, the amount of contaminants removed from each treatment hole could be measured (Table 6).
Based on this data, approximately 1200 Ibs of contaminants were removed by the dual auger system.
These results compare well with the results obtained from monitoring of the CATOX system and
comparisons with pre- and post- treatment sampling of the soil and ground water.
Table 6. Examples of contaminant removal for several treatment holes based on calibrated FID data
Treatment hole no.
1A
1B
1C
3A
3B
3C
2
5
6
7
8
9
10
11
37
38
39
40
Air or steam
air
air & steam
air, then steam
air
air, then steam
air & steam
air, then air & steam
air
air
air
air
air
air
air
air & steam
air & steam
air & steam
air & steam
Time treated (hrs)
4
5
3
2
3
3
6
3
3
1
1
1
1
1
2.5
5
4
4
Contaminant removed (Ibs)
19
28
17
6
7
10
92
50
3
2
2
2
4
1
14
42
34
47
Based on the historical VOC concentration data previously discussed and shown in Figure 3, several sets
of soil and ground water samples were collected to assess system performance and system operational
effects on the surrounding environment. As shown in Figure 10, about 20 different locations were
selected on a defined grid pattern to collect soil and ground water samples inside and around the edges
of the expected treatment zone. Soil and ground water samples were collected at these locations both
before and after treatment. Because the existing historical data showed that most of the contamination in
the treatment area was at depths between 15 and 30 feet deep, at the identified locations ground water
samples were collected at depths of 15 and 25 feet, while soil samples were collected at depths of 10, 20,
and 30 feet or depths of 15, 20, and 25 feet. All samples were collected using direct push sampling
techniques and were analyzed using EPA Methods SW846 8240A for soils and 8260A for ground water.
As can be seen in Figure 10, several of the treatment holes were oriented to coincide with the identified
monitoring locations. Additionally, many of the Treatment Efficiency Characterization treatment holes
were sampled before and after treatment. At these locations, the soil was sampled continuously before
treatment and the VOC distribution assessed using a PID detector. At the location of the highest PID
reading, a soil sample was taken for analysis. After treatment, the soil was sampled at the same location
for comparison. These are the maximum soil contamination values pre and post-treatment identified in
Table 7. The results in Table 7 cover a wide range of soil and ground water contaminant concentration
ranges and should be representative of the overall effectiveness of the rotary steam stripping system.
Cost and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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As can be seen from the results presented in Table 7, the overall removal efficiencies commonly vary
from 69-95%. The percent removals were calculated from total contaminant estimates before and after
treatment and from the GC-calibrated FID data collected during treatment. With a few exceptions, these
results track with the general percent reduction in the levels in the maximum contaminant concentrations.
The sampling data show that the contaminants of concern at the site, methylene chloride, TCE, DCE,
vinyl chloride, and toluene are all removed equally well. None of the contaminants showed consistently
lower removal rates than the other contaminants. In some cases, post-treatment sampling revealed
higher VOC concentrations at some horizons than were detected pretreatment; this is believed to be
caused by the liberation and vertical mixing of contaminants as the dual augers are rotated up and down
the treatment hole. Still, the FID data indicated that, overall, many pounds of VOCs were removed from
each hole.
Table 7. Pretreatment and post-treatment soil and ground water concentrations
Treatment
hole/
monitoring
point #
Hole 1A
Hole 1C
Hole 3A
Hole 3B
Hole 3C
Hole 4A
Hole 4B
Hole 4C
MP14
MP18
MP19
Pretreatment
concentrations (ppm)
Max. soil
C"9/g)
<1
1860
20
7
82
28
900
204
19
<1
<1
Ground
water
(mg/L)
5170
2480
1426
6952
1860
NA
NA
NA
251
1290
1364
Post-treatment
concentrations (ppm)
Max. soil
G"9/g)
120
106
325
11
29
143
26
158
<1
2
6
Ground
water
(mg/L)
1484
724
1019
1135
341
NA
NA
NA
2
198
198
Percent
reduction in
observed
maximum
(%)
69
81
7
84
81
-
97
23
99
85
85
Percent
removal
based on
FID data
(%)
93
55
95
30
95
90
95
95
no data
75
45
Air or steam
Air only
Air, then steam
Air only
Air, then steam .
Air and steam
Air and steam
Air and steam
Air and steam
Air and steam
Air and steam
Air and steam
Treatment time
4 passes, 4 hrs
4 passes, 3 hrs
2 passes, 2 hrs
3 passes, 3 hrs
4 passes, 3 hrs
3 passes, 4 hrs
Many passes,
5 hrs
1 .5 passes,
4 hrs
2.6 passes, 1 hr
1 pass, 1 hr
1 pass, 1 hr
NA = not analyzed
While the percent removal data is impressive, an important evaluation criterion is also the level to which
the contaminant concentrations can be reduced. As shown in Table 7, even after several passes with the
rotary steam stripping system, areas with the highest contaminant concentrations often still require
additional treatment to reduce contaminant concentrations below 100 or 200 ppm, levels considered most
compatible with a proposed in situ anaerobic bioremediation system. This, of course, would increase the
total cost of a remediation effort using this technology.
Based on the results of the TEC study, a general understanding of the contaminant removal rates
obtained by the dual-auger system and effectively handled by the off-gas treatment system was
determined for various operating conditions and contaminant levels. Figure 11 shows the relationship at
this site for the expected contaminant removal rates for various operating conditions. The amount of total
VOC contaminants in each treatment hole was estimated based on the extensive soil and ground water
sampling data generated for this remediation effort through the TEC study. As the dual-auger system
made passes up and down through each treatment hole, the volume of VOCs removed was recorded
continuously with a GC-calibrated FID. The results in this figure are based on the removal data from
more than 100 separate treatment passes of the dual-auger system.
Cost and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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125-,
100-
Based on the information presented in Figure 11, a few general observations can be made. First, higher
air-flow rates provide higher contaminant-removal rates. In areas with low contaminant levels, the
differences are less pronounced. The large contaminant-removal rates available with the dual auger
system suggest that the selection of an appropriate off-gas treatment system is important, because it can
become the rate-limiting factor in treating areas with high contaminant concentrations. In fact, this
limitation occurred in the Northeast Site application in the area of high contaminant concentration where
the catalytic oxidation system could not handle the amount of contaminants being produced by the dual
auger system, forcing the operator to reduce the penetration rate and/or steam injection rate in order to
limit the contaminant removal rate.
In addition, some areas contained TCE and
toluene, compounds with much higher
heats of combustion, in approximate
concentrations of 350 ppm and 100 ppm,
respectively. It was observed that during
treatment in the areas with these
compounds, the maximum temperature
allowable for the catalyst (approx. 1,100° to
1,200°F) could be reached very quickly,
resulting in an automatic over-temperature
system shut-down. Further elevation of the
catalyst temperature could result in
irreversible physical damage to the
catalyst. It is believed that the TCE and
toluene quickly elevated the temperature of
the catalyst when they were combusted.
Slowing the auger penetration rate by 75%
to 90% and decreasing or stopping steam
injection helped to control the catalyst
temperature. As discussed in Sect. 4, the
design of the off-gas treatment system was
based on the high concentration of
methylene chloride in the western portion
of the treatment area, and the potential
impact of the high TCE and toluene
concentrations on off-gas treatment was
not fully understood.
-------
However, sufficient post treatment testing has not been conducted to determine if any long term reduction
in the soil permeability has occured. This does suggest though that, if rotary steam stripping is to be used
in conjunction with another technology, such as air sparging/soil vapor extraction, consideration should be
given to determine whether rotary stripping operations would negatively affect the performance of a
follow-on technology.
As discussed in the previous project chronology, system downtime affected the performance of the rotary
steam stripping system. Figure 12 shows the operating time for the system, which averaged
approximately 50% for the entire project. Figure 13 shows the downtime as a percent of available
operating time per week, identified with the general cause of the downtime. The operating time for the
system over the last half of the project increased continuously and averaged approximately 80% during
the last three weeks of operation.
A summary of the performance of the rotary steam stripping system is provided in Table 8 relative to the
performance measures of the remediation effort. After some initial operational problems, the system met
many of the identified goals. However, problems with the capacity and operation of the off-gas treatment
component did significantly reduce the treatment rate and overall system performance.
System operations 45.7%
GC problems 3.3%
Off-gas down 7.5%
Rig down 31.0%
Off-gas emissions issues 12.5%
Figure 12. Summary of system operations vs downtime.
Cost and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
169
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0)
o>
0.
0)
o
Q
11
12
Operational Week
GC problems
Off-gas down
Off-gas/emissions issues
Rig down
Figure 13. Percent downtime of operations (by week).
Table 8. Pinellas rotary stripping system performance summary
Performance Measure
Quantity of soil/area treated
• Planned
• Actual
Mass of contaminants
• Estimate (pretreatment) in planned treatment area
• Estimate (pretreatment) in actual treatment area
• Estimated mass removed
Remediation goals
• Optimize parameters through a Treatment
Efficiency Characterization
• Removal of VOCs in the soil and ground water to
approx. 100-200 ppm
• Absence of fugitive emissions
• Absence of contaminant migration
Compliance Goals:
Recovery and treatment of volatilized contaminants
to FDEP's limits
Residuals
Quantity of material disposed
Value/ Result
10,000yd3
2,043 yd3
9,000 Ibs
1,300-1, 400 Ibs
1,200 Ibs
• A TEC was performed, although multiple equipment
problems limited the information obtained.
• Some areas were reduced to below 100 ppm; however,
time and funds available prevented reduction below
200 ppm in other areas.
• Monitoring revealed fugitive emissions; these were
reduced by limiting the drilling/injection rate and by
covering the surrounding soil with plastic sheeting.
• Sampling and analyses verified that contaminants did
not migrate outside the treatment area.
Initial discharge from the off-gas treatment system
exceeded the FDEP's limits; however, after repair, limits
were not exceeded.
Used hydraulic oil
Scrubber, boiler, and knock-out tank effluent water
Approx. 100 gal. of used hydraulic oil
Effluent water quantity unknown (approx. 5 gpm); routed
to site wastewater system
Cost and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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Hi 6. ROTARY STEAM STRIPPING SYSTEM COST
The Rotary Steam Stripping project was subcontracted by LMSC to ISF with a fixed price for the
mobilization and demobilization phases, and a time-and-materials reimbursement (with a not-to-exceed
amount) for the treatment operations phase. The mobilization fixed amount was all-inclusive, including
moving the equipment, personnel, supplies, materials, and any other necessary items to the job site prior
to start. The demobilization fixed amount was all-inclusive, including moving the equipment, personnel,
and any remaining items to ISF's next destination after completion of the project.
Under the subcontract, ISF agreed to the following financial terms:
Mobilization
Demobilization
Time and materials not to exceed
Total subcontract established amount
$ 95,000.00
$ 51,000.00
$773.651.08
$919,651.08
ISF was to perform all work according to the Scope of Work, dated April 17, 1996, and the subsequent
clarifications. This not-to-exceed, time-and-materials type contract was based on crew-days on-site and
did not specify the volume of soil and ground water to be treated.
Table 9 shows the breakdown of project costs in accordance with accepted Federal Remediation
Technologies Roundtable13 cost elements. Based on the nature of equipment used on such a project,
equipment operating rates can be quite high and were the largest component of cost. In addition, standby
rates were established for this project in case LMSC stopped the ISF operations and equipment was sitting
idle. With this arrangement, full equipment operating costs were not incurred; instead, a minimal rate to
cover the equipment rental rate was incurred.
Unit treatment costs are often calculated based on the volume of contaminants removed or the volume of
soil treated. Either method must be used carefully because of the variation in treatment inherent at any site.
For example, providing unit costs based on the volume of soil treated will vary based on the relative
contamination level of the soils being treated, with soils having higher contaminant levels requiring longer
treatment. On the other hand, providing unit costs based on the volume of contaminants removed will also
vary based on the relative contaminant levels of the soil being treated. As discussed in Section 5, fewer
pounds per hour of contaminant are removed in soils with lower contaminant levels. Therefore, in using
either method, consideration should be given to both the contaminant level of the soil to be treated and the
desired target treatment level.
Another complicating factor is that the rotary steam stripping system consists of several subsystems, each
of which has a substantial impact on overall system performance and cost. In the application at the Pinellas
STAR Center's Northeast Site, the off-gas treatment system was a major contribution to the unit treatment
costs that may or may not be required or could be modified at a different site. Additionally, each of these
systems has its own associated downtime that affects the overall system performance and cost.
Therefore, unit treatment costs as a function of the volume of soil treated, the initial contaminant levels in
each treatment hole, and the required treatment levels were chosen as identifying factors. Based on the
data provided in Table 9, general estimates of the costs per day for the dual auger and the off-gas treatment
systems can be defined. Based on the results shown in Table 7 and Figure 11, the time required to reduce
the various treatment hole contaminant levels to levels of approximately 200 to 300 ppm was used to
calculate the unit removal and treatment costs.
Cosf and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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Table 9. Pinellas Rotary Steam Stripping Project cost by interagency work breakdown structure (WBS)
Cost element
(with interagency
WBS Level 2 code14)
Preoroiect operations visit
Mobilization and preparatory work
(331 01)
Monitoring, sampling, testing, and
analysis (331 02)
Physical treatment (331 13)
Disposal [other than commercial
(331 18)]
Demobilization (331 21)
iin nun inn i in i in in ii I up Him inn
Description
Visit to similar project
CAT 245D transport to Pinellas
Dual auger transport to Pinellas
Parts trailer transport to Pinellas
Trucks and dual auger hood transport
Steam processing equipment transport
Personnel & equipment load out
Personnel & equipment unload & assemble
Operational precheck
Pretreatment sampling and analysis
Pre-TEC sampling and analysis
Post-TEC sampling and analysis
Post-treatment sampling and analysis
Equipment
CAT 245D $ 76,586
Dual auger system $ 53,21 1
Backhoe $11,643
Air compressor $ 8,853
Generator $ 14,889
Support equipment $ 29,054
Boiler $ 42,957
Gas chromatograph $ 15,417
Off-gas treatment equip. $ 21 5,657
Labor (incl. travel & per diem)
Supplies & Materials
Fuel
Hydraulic oil
CAT 245D
Dual auger system
Parts trailer
Trucks and dual auger hood
Steam processing equipment
Personnel & equipment disassemble & load
Personnel & equipment off-load
' / ' ^ ' ^>*, ' 'x
Costs
($)
$ 2,400
$ 10,000
$ 15,000
$ 11,000
$ 11,000
$ 19,400
$ 6,600
$ 12,000
$ 10,000
$ 23,000
$ 9,000
$ 9,000
$ 18,000
$ 468,267
$ 259,097
$ 25,250
$ 21,037
$ 200
$ 5,000
$ 7,000
$ 6,000
$ 6,000
$ 12,400
$ 8,000
$ 6,600
TOTAL:
Subtotals
($)
$ 2,400
$ 95,000
$ 59,000
$ 773,651
$ 200
$ 51,000
$ 981,251
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As previously discussed, the operation of the rotary steam stripping treatment at Pinellas was affected by a
number of operational issues and design limitations that caused great variations in the observed treatment
rates. Contaminant mixtures and concentrations also affected the rate of treatment, particularly in the
western portion of the treatment area. Because of these operational variations, the unit treatment costs for
this project are more accurately represented by a range rather than a discrete value (Table 10).
Based on the time-and-materials contract used at this site, the operating costs of the rotary steam stripping
system were approximately $13,000/day. In areas of low contaminant concentration, as many as 5 to 6
holes could be treated in one day, while in the areas of high contaminant concentration, often only one hole
could be treated in one day. Based on this data, the operating costs of the system varied from
approximately $50-$400/yd3 of treated soil, depending on the contaminant levels.
Table 10. Range of observed unit treatment costs in the Pinellas rotary steam stripping project
Holes per day
1
2
3
4
5
6
Volume per day
(vd3)
40
80
120
160
200
240
Volume treated at
this rate in 60 days
(vd3)
2,400
4,800
7,200
9,600
12,000
14,400
Operating Cost,
based on $13,000
per crew-day
($/vd3)
$325
$163
$108
$81
$65
$54
Mob./Demob. Cost,
based on 60 day
treatment
period($2433/day)
($/vd3)
$62
$31
$21
$16
$12
$10
Total
Cost
($/vd3)
$387
$194
$129
$97
$77
$64
The operating costs can also be viewed from the standpoint of costs per pound of contaminant treated. This
method of assessing costs is often presented because it can more easily address the differences in
contaminant levels in the treatment holes. Calculating operating costs based on this method, we determined
that the unit operating costs for the system varied from $300-$500/lb of contaminant removed.
Key factors that affect overall treatment costs are the on-line time of the entire system, the level of
contaminants in the treatment holes, and the target concentration levels one would like to achieve. These
factors need to be considered and evaluated critically when trying to assess the expected treatment costs at
other sites. Additionally, site-specific costs for mobilization/demobilization, technology performance
monitoring, and environmental safety and health monitoring should be considered and included to determine
the overall implementation cost of this technology at a specific site.
Cost and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
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•I 7. REGULATORY/INSTITUTIONAL ISSUES
In July 1993, DOE, EPA, FDEP, and LMSC entered into an agreement with the ITRD Program to evaluate
innovative technologies to remediate ground water contamination at the Pinellas STAR Center Northeast
Site effectively and expeditiously.
Under Section II.D.1 of the Pinellas STAR Center's HSWA Permit, interim measures may be conducted at
SWMUs after EPA approval. Section II.D.3 requires the permittee to notify the EPA's Regional
Administrator as soon as possible of any planned changes, reductions, or additions to the interim
measures. The proposed rotary steam stripping project would temporarily interrupt the operation of the
existing interim measures (pump and treat with air stripping); therefore, the Pinellas STAR Center ER's
Program provided notice to the EPA and FDEP of a planned change (the implementation of ITRD field
activities) to the approved interim measures and proposed implementation schedule for concurrence in
August 1996. Authorization for implementation of the activities was received in August 1996.
In addition to the HSWA permit issues, FDEP required notification and authorization for air emissions from
the rotary steam stripping project. In July 1996, DOE/PAO requested authorization to conduct the rotary
steam stripping project. The PAO received authorization in August 1996 9. Two further amendments to the
August authorization were received based on changes in equipment and the end date of the project 10. The
FDEP authorization specifically identified each component of the off-gas treatment system and required
the use of that model or its equivalent during the project and a Professional Engineer's certification that the
system will comply with FDEP's standards. Additional stipulations were as follows:
• The operating time of the air treatment system would not exceed 8 hrs/day and 90 operating days.
• The air treatment system would reduce VOC emissions by at least 90%.
• The maximum allowable air emissions from the air treatment system were as follows.
(Pollutant
Methylene chloride
Other VOCs
Ibs/hr
2.01
1.15
Ibs/day
16.06
9.2
Total project (Ibs)
1447
828
• Continuous monitoring of the inlet process stream would be performed with an FID organic vapor
analyzer (HNU Model PI201 or equivalent), real-time analysis of the CATOX inlet, CATOX outlet, and
scrubber outlet process stream by syringe sampling of the process stream and direct injection into an
on-site FID/GC.
• Daily summary logs would be completed.
• If system operations or equipment indicated that the project was not operating according to the above
requirements, the project would cease operation until the problems were corrected.
Local fire authorities required a permit for use of the propane tank that fueled the CATOX unit. Minimum
distances to vegetation and ignition sources were conditional to issuance of the permit. Any future users
of the steam stripping technology that involves fuel tanks should check with their local authorities for any
necessary permitting.
Upon start-up of the rotary steam stripping operations, compliance with the FDEP air emissions
authorization became a very significant part of the project. Initially, the field GC was not operational and
necessitated the use of the LMSC Analytical Laboratory. This led to an approximate 1-day delay in
receiving analytical results. When the CATOX efficiency was found to be below the FDEP's limits,
DOE/PAO limited operations to treating one hole at a time and not proceeding to the next hole until
analytical results confirmed that emissions were within the FDEP's limits. Confirmation of continual
operations within FDEP's limits allowed the one-hole-at-a-time restriction to eventually be eliminated;
however, duplicate sampling and analyses continued throughout the remainder of the project to ensure
compliance.
Cost and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas.STAR Center
174
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8. SCHEDULE
Figure 14 shows the associated tasks and schedule for the demonstration and evaluation of the rotary
steam stripping system at the Pinellas STAR Center.
ID
1
11
12
15
16
17
18
19
21
21
22
23
24
25
26
27
28
29
30
31
32
33
36
37
38
Task Name
Procurement Process
Planning 8 documents
Mobilization
Repair CAT 2450
TEC
Treatment Ops
Repair Catox
Fugutive emissions
Repair Scrubber
Treatment Ops
A/W gas analysis
Treatment Operations
Treatment Ops
OC discrepancy
Treatment Ops
Repair augers , .
Treatment Ops
Repair drive table
Treatment Ops
Repair boiler/augers
Treatment Ops
Demob. & Cleanup
Project Completion
Project summary report
Final Invoice
Start
4/19/96
8/23/96
12/2/96
1/13/97
1/20/97
100/97
100/97
213197
2/5/97
2/7/97
2/11/97
2/12/37
2/12/97
2/13/97
2/17/97
2/1 8/97
2/25/97
3/7/97
3/19/97
3/27/97
3/31/37
4/3/97
4/14/97
4/14/97
4/30/97
Finish
8/20/96
1/3/97
1/10/97
1H7/97
2/11/97
1/29/97
1/31/97
2/4/97
2/8/97
2/10/97
2/11/97
4/2/97
2/12/97
2/14/97
2/17/97
2/24/97
3/6/97
3/18/97
3/26/97
3/28/97
4/2/97
4/11/97
4/30/97
4/30/97
4/30/97
1996 . 1997
Mar I Apr I May lJun I Jul lAuq ISeo Oct iNov I Dec I Jan iFeb I Mar I Apr I May lJun I Jul I Aua I Sep Oct I Nov
I
•
I
I
I
I
I
I
I
1
1
•
I
1
1
^P
+ 4/30
Figure 14. Project schedule.
Cosf and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
175
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•I 9. OBSERVATIONS AND LESSONS LEARNED
Hi Cost Observations and Lessons Learned
The rotary steam stripping system deployed at the Pinellas STAR Center's Northeast Site consisted of a
dual-auger rotary drill tower for contaminant removal, a CATOX system for VOC vapor treatment, and an
acid-gas scrubber for off-gas treatment. Although each subsystem consists of standard equipment,
operating the entire system efficiently and reliably is demanding. Mechanical and operational problems are
a given for this type of heavy equipment operation, and provisions should be made in the contracting to
minimize costs during system downtime. VOC vapor and off-gas treatment can be significant portions of the
overall treatment costs for this type of system. Accurate design and operation of these subsystems is
crucial for the cost effective application of this technology at a site.
Other project cost observations include:
• The major cost items (74% of the entire project cost) were equipment and operating costs.
• The inability of the off-gas treatment system to process all of the contaminant vapors removed by the
dual-auger system was a shortfall in the design process that severely affected the subsurface VOC
removal rate and the cost per cubic yard of soil and ground water treated and the overall cost-
effectiveness of the system.
•H Performance Observations and Lessons Learned
The ISF dual auger system deployed at the Pinellas STAR Center demonstrated the following
performance characteristics.
• The ISF dual augers demonstrated the ability to remove large amounts of contaminants from the soil
and ground water in a treatment column.
• For the columns that were sampled before and after treatment, the rotary steam stripping system
removed an average of 77% of the VOCs in the ground water and soil, and reduced the maximum
contaminant concentrations by an average of 71 % (Table 7).
• The system did not consistently remove VOCs from the site's soil and ground water to a level of 200
ppm or less, especially in the areas of high initial concentrations.
• The only effects of the rotary steam stripping system on the surrounding environment was the escape
of air outside the bore hole, which seemed to be limited to a radius approximately 6 ft from the shroud.
• The injection of only air appears to have produced a removal rate similar to that when air and steam
are used; however, the ability of air by itself to quickly reduce contaminant levels of VOCs to very low
final concentration is questionable, and the injection of only air appears to leave more contaminants
deposited at shallower depths than when air and steam are injected.
• The higher the flow rate of air and/or steam, the better the removal of contaminants.
The project provided the following lessons learned on performance:
• Preproject discussions with regulatory agency personnel are essential. A cooperative relationship with
the regulators, including full disclosure of all issues and problems that arise during a project, will
minimize delays in obtaining authorizations and can facilitate the use of alternative emissions control
methods and associated equipment.
• Any necessary permits, such as air emissions, should have long enough periods of performance to
allow for potential delays in system mobilization and operation..
Cosf and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
176
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• The location, availability, and transport of all necessary equipment should be thoroughly evaluated for
any impact on the project schedule.
• Evaluators of rotary steam stripping technologies should research the average downtime that a vendor
experienced during past projects as a result of equipment failures and repairs.
• The impact of fugitive emissions on a project should be evaluated and planned for in case emissions
are detected.
• Off-gas treatment systems should be evaluated for proper capabilities based on contaminant mass and
combustion characteristics. The ability to increase treatment capability quickly, if needed, should be
evaluated.
• Soil and ground water sampling after rotary steam stripping is performed can be delayed up to 2 to 3
weeks after treatment because of the inability of sampling vehicles to traverse the soft, loosened soil of
each borehole.
• All site geology/hydrology characteristics may be changed following rotary steam stripping treatment,
possibly affecting the ability to collect post-treatment samples (i.e., hydraulic conductivity, relatively firm
soil, etc.).
• Patent issues, though not a factor in this application, should be thoroughly researched and evaluated
and considered part of the bid review process for this technology.
• Utility supplies vital to project operations should have back-up supplies in the event of loss of that
utility.
• Fuel storage regulations should be researched with local authorities; permits may need to be secured.
HI Summary
Based on the results of this demonstration, the ISF dual auger rotary steam stripping system is an
innovative technology capable of providing in situ treatment of VOC-contaminated soil and ground water.
During the demonstration of this technology at the Pinellas STAR Center, the ISF system was very effective
in liberating large quantities of VOCs from the site soil and ground water. During the operating period, 48
treatment holes were drilled to a depth of approximately 32 feet, resulting in the treatment of over 2,000 yd3
of soil and ground water and the removal of approximately 1,200 pounds of VOCs.
Initially, many operational problems were encountered with the system, especially with the off-gas treatment
component because of high contaminant loading. As the project progressed, these problems were reduced
through operational adjustments. The off-gas treatment capacity of the catalytic oxidation unit, initial
operational problems, and mechanical breakdowns slowed the expected treatment rates for the system at
the site. This prevented the system from meeting some of the performance objectives and treatment
volumes initially expected in this remediation.
Cost and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
177
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•I 10. REFERENCES
1. Installation Assessment, Pinellas Plant, U.S. Department of Energy, Comprehensive Environmental
Assessment and Response Program, Albuquerque Operations Office, Albuquerque, N.M., 1987.
2. RCRA Facility Investigation Report, Pinellas Plant, Vol. 1—Text, U.S. Department of Energy,
Environmental Restoration Program, Albuquerque Operations Office, Albuquerque, N.M., 1991.
3. RCRA Hazardous and Solid Waste Amendments Permit, U. S. Department of Energy Pinellas Plant,
Largo, Florida. EPA ID No. FL6-890-090-008, U.S. Environmental Protection Agency, February 9,
1990.
4. Interim Corrective Measures Study, Northeast Site, TPA2 6350.80.01, prepared by CH2M Hill for the
U.S. Department of Energy and General Electric Company, Neutron Devices Department, Largo, Fla.,
May 1991.
5. Corrective Measures Study Report, Northeast Site, Pinellas Plant, Largo, Florida, U.S. Department of
Energy, Environmental Restoration Program, Albuquerque Field Office, Albuquerque, N.M., 1993.
6. Corrective Measures Implementation Plan, Northeast Site, Pinellas Plant, Largo, Florida, U. S.
Department of Energy, Environmental Restoration Program, Albuquerque Field Office, Albuquerque,
N. M., March 1996.
7. Toxic Treatments, In Situ Steam/Hot-Air Stripping Technology, Applications Analysis Report,
EPA/540/A5-90/008, Risk Reduction Engineering Laboratory, U.S. Environmental Protection Agency,
Cincinnati, Ohio, March 1991.
8. Advanced Techniques for In Situ Remediation, Milgard Environmental Corporation, Livonia, Mich.,
MEC-195, September 1993.
9. La Mori, P.N., "Using In-Situ Hot Air/Steam Stripping (HASS) of Hydrocarbons in Soils", HazMat
International '94, Philadelphia, Pa., May 1994.
10. Technology Profiles, Seventh Edition, Superfund Innovative Technology Evaluation Program, EPA
Office of Research and Development, Washington, D.C., November 1994, EPA/540/R-94/526.
11. Interim Corrective Measures Study Addendum #2, Northeast Site, U.S. Department of Energy and
Lockheed Martin Specialty Components, Largo, Fla., August, 1996.
12. Notice of Amended Revised Authorization to Conduct Rotary Steam Injection/Extraction Remediation
Project, Florida Department of Environmental Protection, Tampa, Fla., February, 1997.
13. Guide to Documenting Cost and Performance for Remediation Projects, Member Agencies of the
Federal Remediation Technologies Roundtable, March 1995, EPA-542-B-95-002.
(downloadable at http://clu-in.com/pubitech.htm)
14. HTRW Remedial Action Work Breakdown Structure, Hazardous, Toxic, Radioactive Waste
Interagency Cost Engineering Group, February 1996.
(downloadable at http://giobe.lmi.org/lmi_hcas/wbs.htm)
Cost and Performance Report-Dual Auger Rotary Steam Stripping, Pinellas STAR Center
178
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11. VALIDATION
"This analysis accurately reflects the performance and costs of the remediation."
r*
David S. Ingle, Pinellas Area Office
U.S. Department of Energy
Mike Hightower, Tecrmical Coordinator
Innovative Treatment Remediation DemonsbaBon Program
Sandia National Laboratories
Cost and Performance Report—Dual Auger Rotary Steam Stripping, Pinellas STAR Center
179
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA FEDERAL CENTER
100 ALABAMA STREET, S,W.
ATLANTA, GEORGIA 30303-3104
4WD-FFB *"*' ' 5
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
The United States Department of Energy
Pinellas Plant
Attn: Mr. David Ingle
P.O. Box 2900
Largo, FL 34649
SUBJ: Cost and Performance Reports for the:
1) Dual Auger Rotary Steam Stripping Technology, and
2) Pervap Membrane Separation Technology
Demonstrations at the^Northeast Site
DOE Pinellas Plant, FlT
EPA I.D. Number FL6 890 090 008
Dear Mr. Ingle:
The Environmental Protection Agency (EPA) , Region 4, has
completed our review of the above referenced documents. Both of these
reports appear to accurately convey information gathered fay the
Innovative Treatment Remediation Demonstration (ITRD) Team for the two
different technologies that were demonstrated on the small scale at
the Northeast site.
The activities associated with the Northeast Site under the
direction of the ITRD have been very important to the Agency because
the successful demonstration of the various technologies would
ultimately lead to a remedy selection for this solid waste management
unit. Additionally, the information gained from these activities is
valuable in determining the cost/benefit of using these innovative
technologies at other sites. EPA remains committed to working with
the Department of Energy (DOE) at the former Pinellas Plant to
document the success of these technology demonstrations, for a final
remedy selection at this site, and eventually facility restoration.
If you have any questions regarding the ITRD at the Northeast
Site then please contact me at (404) 562-8550.
Sincerely,
Carl R. Froede Jr., P.O.
DOE Remedial Section
Federal Facilities Branch
Waste Management Division
cc: Eric Nuzie, FDEP
Jim Crane, FDEP
R«eyd*d/H«cycl«bl» • Pitolad with Vogstabte OI Based Inks on 100% Recycled Pap«r (40% Poslconsumw)
180
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Law/ton Chiles
Governor
Department of
Environmental Protection
Twin Towors Building
2600 Blair Stems Road
Tallahassee, Rorkls 32309-2400
February 5,1993
Virginia S. Wethofoll
Sacrotary
Mr. David Ingle
United States Department of Energy
7887 Brian Dairy Road
Suite 260
Largo, Florida 33777
Dear Mr, Ingle:
I have reviewed the Cost and Performance Report, Dual Anger Rotary Steam Stripping. Pinellas
Northeast Site, Largo, Florida, dated December 1997, and find it acceptable. If you should have any
questions please feel free to contact me.
If I can be of any further assistance please feel free to contact me at (850) 921 9983.
Sincere
s
//S
x3ohn IL Armstrong P.O.
/ Remedial Project Manager
Date
Cheryl Walker-Smith, USEPA Atlanta
Satish Kastury, FDEP
ESKfrflg^
"Protect, Conserve and Manage Florida's Environment and Natural Resources"
Primed an recycled paper.
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In Situ Anaerobic Bioremediation
at Pinellas Northeast Site,
Largo, Florida
183
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In Situ Anaerobic Bioremediation
at Pinellas Northeast Site,
Largo, Florida
Site Name:
Pinellas STAR Center
Northeast Site
Location:
Largo, Florida
Contaminants:
- Chlorinated solvents, including
trichloroethene, methylene
chloride, dichloroethene, and
vinyl chloride
- Concentrations ranged from 10-
400 mg/kg
- DNAPL suspected to occur in
localized areas
Period of Operation:
February 7, 1997 to June 30, 1997
Cleanup Type:
Demonstration (ITRD Technology
Demonstration)
Vendor/Consultant:
Lockheed Martin Specialty
Components
Additional Contacts:
David Ingle, Site Management
DOE/GJO Environmental
Restoration Program Manager
(813) 541-8943
Technology:
In Situ Anaerobic Bioremediation
- Three, 8-ft deep gravel-filled,
surface infiltration trenches and
two, 240-ft long horizontal wells
with 30-ft screened intervals
- Groundwater extracted from
upper horizontal well and
recirculated via surface trenches
and lower horizontal well at a
rate of about 1.5 gpm
- Benzoate, lactate, and methanol
added to recirculated water to
serve as nutrients for
dechlorinating bacteria
- 250,000 gallons of water
circulated during pilot study over
five month period
Cleanup Authority:
RCRA
Regulatory Point of Contact:
EPA Region 4 and State:
Florida Department of
Environmental Protection
Waste Source:
Leakage of solvents or resins from
drum/container storage
Purpose/Significance of
Application:
Demonstration of in situ anaerobic
bioremediation technology used to
supplement an ongoing system of
pump-and-treat with air stripping
Type/Quantity of Media Treated:
Groundwater
- Water table present approximately 3-4 feet below ground surface
- Aquifer characterized as sandy
- Hydraulic conductivity of surficial aquifer in study is relatively
heterogeneous; zones of reduced hydraulic conductivity occur at depths
between 10 to 14 feet and 22 to 29 feet
- Approximately 250,000 gallons of water were treated
Regulatory Requirements/Cleanup Goals:
- The objectives of this demonstration included evaluating the use of nutrient injection to enhance in situ
anaerobic biological degradation of chlorinated VOCs in areas of moderate contaminant concentrations and
obtaining operating and performance data on this technology.
Results:
- Evaluated use of nutrient injection to enhance in situ anaerobic biological degradation of chlorinated VOCs in
areas of moderate contaminant concentrations
- Obtained operating and performance data to optimize the design and operation of a full-scale system
- VOC concentrations reduced 60% - 91% within four to eight weeks after nutrient arrival
- Contaminant reduction probably result of groundwater mixing and contaminant redistribution
- Limiting factors for successful, cost effective implementation are ability to deliver appropriate nutrients to all
contaminated areas and hydraulic travel times
184
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In Situ Anaerobic Bioremediation
at Pinellas Northeast Site,
Largo, Florida (continued)
Cost:
Total cost of pilot remediation project was $397,074, including:
- Mobilization and preparatory work - $35,000
- Monitoring, sampling, testing, and analysis - $23 8,310
- Groundwater collection and control - $87,536
- Biological treatment - $23,748
- General requirements - $ 12,480
Description:
The Pinellas STAR Center operated from 1956 to 1994, manufacturing neutron generators and other electronic
and mechanical components for nuclear weapons under contract to the U.S. Department of Energy and its
predecessor agencies. The Northeast site is associated with the location of a former waste solvent staging and
storage area. In the 1950s and 1960s, an existing swampy area at the site was used for staging and burial of
construction debris and drums, some of which contained solvents. The site consists of a shallow groundwater
aquifer contaminated with a variety of VOCs, including chlorinated solvents such as trichloroethene, methylene
chloride, dichloroethene, and vinyl chloride.
From February 7, 1997 to June 30, 1997 a demonstration using in situ anaerobic bioremediation was conducted
at the site. The demonstration was part of a program at the Pinellas STAR Center to evaluate several innovative
remediation technologies that could enhance the cost or performance of an existing pump-and-treat system. The
pilot system was located in an area of the site that had total chlorinated contaminant concentrations in
groundwater generally ranging from 10-400 mg/kg, with one monitoring well having concentrations hi excess of
2,900 mg/kg. The bioremediation pilot system consisted of three 8-ft deep gravel-filled, surface infiltration
trenches and two 240-ft long horizontal wells with 30-ft screened intervals. The horizontal wells, directly
underlying and parallel to the middle surface trench, were at 16- and 26-ft depths. The study area was about 45
feet by 45 feet and extended from the surface down to a thick, clay confining layer 30 feet below the surface.
Groundwater was extracted from the upper horizontal well and recirculated via the surface trenches and the
lower horizontal well while benzoate, lactate, and methanol were added to the recirculated water to serve as
nutrients for the dechlorinating bacteria.
During this period, groundwater was extracted and recirculated at a rate of about 1.5 gpm. Approximately
250,000 gallons of water, based on soil porosity of about two pore volumes, were circulated during the pilot
study. Tracer and nutrient monitoring data indicated that nutrients were delivered to 90% of the central treatment
area during operations. Where nutrient breakthrough was observed, significant declines in total chlorinated VOC
concentrations were generally observed.
The cost of the pilot system totaled approximately $400,000, with over half the costs associated with sampling
and analyses. Most of the sampling and analyses were discretionary and were used to verify the system concept
and design. This level of sampling would not be needed during a full-scale bioremediation project. System
construction costs were about $90,000, while operating costs were about $30,000 or $0.12 per gallon of water
treated. The extensive modeling, hydrogeologic, nutrient transport, and operating cost data developing during
this pilot system operation suggest that the Northeast Site could be remediated using nutrient injection in
approximately 2-3 years at a cost of about $4-6M.
185
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1. SUMMARY
In early 1997, the Innovative Treatment Remediation Demonstration (ITRD) Prog ram conducted a pilot
study at the Pinellas STAR Center's Northeast Site to treat chlorinated volatile organic compounds (VOC)
using in situ anaerobic bioremediation. The Northeast Site is characterized by VOC contamination of a
shallow, sandy, surficial aquifer. Monitoring data indicate that some biodegradation of these contaminants
is already occurring at the site. The primary objectives of this pilot study were to 1) evaluate the use of
nutrient injection to enhance in situ anaerobic biological degradation rates of chlorinated VOCs in areas of
moderate contaminant concentrations and 2) obtain operating and performance data to optimize the
design and operation of a full-scale system. During the short operational period of this pilot study, there
was no emphasis on reducing any contaminants to a specific regulatory level.
The pilot system was located in an area of the site that had total chlorinated contaminant concentrations in
ground water generally ranging from 10-400 ppm, with one monitoring well having concentrations in
excess of 2900 ppm. The bioremediation pilot system consisted of three 8-ft deep, gravel-filled, surface
infiltration trenches and two 240-ft long horizontal wells with 30-ft screened intervals. The horizontal wells,
directly underlying and parallel to the middle surface trench, were at 16- and 26-ft depths. The study area
was about 45 feet by 45 feet and extended from the surface down thirty feet to a thick, clay confining layer
30 feet below the surface. Ground water was extracted from the upper horizontal well and recirculated via
the surface trenches and lower horizontal well while benzoate, lactate, and methanol were added to the
recirculated water to serve as nutrients for the dechlorinating bacteria. The nutrient concentrations were
selected based on an earlier laboratory treatment study conducted through the ITRD Program. To assess
hydraulic flow characteristics and nutrient delivery, a bromide tracer was added to the water reinjected
through the deep horizontal well and an iodide tracer was added to the water fed to the surface trenches.
VOC, tracer, and nutrient concentrations were monitored bi-weekly at 16 well clusters (each with 4
vertically discrete sampling intervals) spaced throughout the treatment area. VOC concentrations of the
extracted ground water were also continuously monitored.
The system operated from February 7,1997 to June 30,1997. During this period, ground water was
extracted and recirculated at a rate of about 1.5 gpm. Approximately 250,000 gallons of water, based on
soil porosity of about two pore volumes, were circulated during the pilot study. Tracer and nutrient
monitoring data indicated that nutrient were delivered to 90% of the central treatment area during
operations. Wells not showing breakthrough were generally in the areas of lower conductivity and
perimeter wells. Where nutrient breakthrough was observed, significant declines in total chlorinated VOC
concentrations (70-99%) were generally observed. These values correlated well with the results observed
from the extraction. For those wells where nutrient arrival was not observed, generally in areas of lower
permeability or perimeter wells, only modest contaminant reductions were recorded. Degradation rates of
as high as 1-2 ppm per day were observed in the higher concentration areas, greater than 100 ppm, while
in areas with lower concentrations, degradation rates of 0.05 to 0.10 ppm per day were observed. There
was no evidence of significant degradation product build up in any monitoring well, and many wells with
contaminant concentrations below 10 ppm showed contaminant reductions to regulatory allowable levels.
The cost of the pilot system totaled approximately $400,000 with over half the costs associated with
sampling and analyses. Most of the sampling and analyses were discretionary and were used to verify
the system concept and design. This level of sampling would not be needed during a full-scale
bioremediation project. System construction costs were about $90,000 while operating costs were about
$30,000 or $0.12 per gallon of water treated. The extensive modeling, hydrogeologic, nutrient transport,
and operating cost data developed during this pilot operation suggest that the Northeast Site could be
remediated using nutrient injection in approximately 2-3 years at a cost of about $4-6M. From the results
of the pilot study, nutrient addition to stimulate existing in situ anaerobic biological degradation of
chlorinated solvent contaminated soil and ground water appears to be a feasible and cost effective
remediation approach at the Pinellas Northeast Site for areas of moderate contaminant levels.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
186
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2. SITE INFORMATION
Identifying Information
Facility.
Location:
OU/SWMU:
Regulatory Driver:
Type of Action:
Technology:
Period of operation:
Treatment area:
Site Background
Pinellas Science, Technology, and Research (STAR) Center,
formerly the U. S. Department of Energy Pinellas Plant
Largo, Pinellas County, Florida
Northeast Site
RCRA
ITRD Technology Demonstration
In situ anaerobic bioremediation
February 1997 to July 1997
45 ft x 45 ft x 30 ft (60750 ft3)
The Pinellas STAR Center occupies
approximately 100 acres in Pinellas
County, Florida, which is situated along
the west central coastline of Florida
(Figure 1). The plant site is centrally
located within the county, and is bordered
on the north by a light industrial area, to
the south and east by arterial roads, and
to the west by railroad tracks. The
topographic elevation of the Pinellas
STAR Center site varies only slightly,
ranging from 16 feet MSL in the southeast
corner to 20 feet MSL in the western
portion of the site. Pinellas County has a
subtropical climate with abundant rainfall,
particularly during the summer months.
The Northeast Site includes the East
Pond and is located in the northeast
portion of the Pinellas STAR Center site.
The Northeast Site is covered with
introduced landscaping grass and
contains no permanent buildings. The
site contains approximately 6 acres and is
generally flat, with slight elevation
changes near the pond. Access to the
Northeast Site is restricted and protected
by fencing.
Site History
PINELLAS
PLANT
Gulf of
Mexico
Tampa Bay
Petersburg
Figure 1. Pinellas STAR Center location.
The Pinellas Plant operated from 1956 to 1994, manufacturing neutron generators and other electronic
and mechanical components for nuclear weapons under contract to the U.S. Department of Energy and its
predecessor agencies (SIC Code 9631A-Department of Energy Activities).
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
187
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The Northeast Site is associated with the location of a former waste solvent staging and storage area.
From the late 1950s to the late 1960s, before construction of the East Pond, an existing swampy area at
the site was used to dispose of drums of waste and construction debris. The East Pond was excavated in
1968 as a borrow pit. In 1986, an expansion of the East Pond was initiated to create additional storm
water retention capacity. Excavation activities ceased when contamination was detected directly west of
the East Pond.
The Northeast Site was identified as a Solid Waste Management Unit (SWMU) in a RCRA Facility g
Assessment (RFA)1 conducted by EPA Region IV. Subsequently, a RCRA Facility Investigation (RFI)
was completed and approved in compliance with the facility's Hazardous and Solid Waste Amendments of
1984 (HSWA) permit?
An Interim Corrective Measures (ICM) Study4 was developed and submitted to EPA for approval. EPA
issued final approval of the ICM in October 1991, and an interim ground water recovery system for the
Northeast Site was installed and commenced operation in January 1992. A Corrective Measures Study
Report was submitted to EPA in March 1993 and approved in November 1994 ' A Corrective Measures
Implementation Plan was submitted to EPA in March 1996 and approved in June 1996. The current
system now consists of seven ground water recovery wells equipped with pneumatic recovery pumps that
transfer ground water for temporary storage in a holding tank prior to being pumped to a ground water
treatment system.
Hi Release Characteristics
The primary management practice that contributed to contamination at this site was the storage of
drums/containers. Because the site was used in the 1950s and 1960s for staging and burial of
construction debris and drums, some of which contained solvents, contamination at the Northeast Site is
believed to be the result of leakage of solvents or resins from those drums. The Pinellas Northeast Site
consists of a shallow ground water aquifer contaminated with a variety of VOCs, including chlorinated
solvents such as trichloroethylene, methylene chloride, dichloroethylene, and vinyl chloride. A recent
debris removal activity at the site removed multiple buried drums, many of which were empty but contained
solvent residue. The ongoing ICM system (pump and treat with air stripping) continues to recover
contaminants from the site and has been successful in preventing off-site migration of VOCs.
•I Site Contacts
Site management is provided by the DOE Pinellas Area Office (DOE/GJO). The DOE/GJO Pinellas STAR
Center Environmental Restoration Program Manager is David Ingle [(813)-541-8943]. The technical
contact for the Pinellas Plant in situ anaerobic bioremediation project is Mike Hightower, the ITRD
technical coordinator at Sandia National Laboratories [(505)-844-5499].
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3. MATRIX AND CONTAMINANT DESCRIPTION
The anaerobic bioremediation system treated a. matrix of soil and ground water to enhance the
degradation of chlorinated organic compounds (in situ).
^B Site Geology/Hydrology
Based on analysis of soil borings, details of well, construction, and environmental studies at the Pinellas
STAR Center, the thickness of the surficial deposit below the site ranges from 25 to 35 feet and is primarily
composed of silty sand. Figure 2 shows the primary geologic units at the site. The top of the Hawthorn
Group (composed primarily of clay) is encountered at depths approximately 30 feet below ground surface.
The thickness of the Hawthorn Group ranges from 60 to 70 feet. The water table at the Northeast Site is
generally 3 to 4 feet below the ground surface. The ground water gradient and ground water flow velocity
at the site are both very low.
The ground water system at the
Pinellas Star Center is composed of
three primary units: (1) an upper unit,
the surficial aquifer; (2) an
intermediate confining unit, the
undifferentiated portion of the
Hawthorn Group; and (3) a lower unit,
the Floridan aquifer. Undifferentiated
sediments lie below the surficial
aquifer and above the Floridan aquifer
in Pinellas County. Because of the low
permeability of these sediments in this
region, these upper sediments are not
considered part of the intermediate
aquifer system and are generally
considered to be a confining unit in the
area of the Pinellas STAR Center.
Measurements performed in the
bioremediation study area, including
down-hole flowmeter tests, have
suggested that the surficial aquifer in
the study area is relatively
heterogeneous with regard to hydraulic
conductivity. These heterogeneities
appear in the vertical and horizontal
direction. Specifically, zones of
reduced (i.e., by a factor of 10 or
greater) hydraulic conductivity occur at
depths between 10 to 14 feet and 22 to
27 feet. The bulk of the contamination
in the bioremediation study area has
been detected within these low
permeability layers.
South North
Cross Section along Longitude 82*45'
t 27*45" Pinellas Plant oa-nn-
t. */ *tj 27*52*30''
Upper _•=:-• S-—= ' •> .- 4
2SST : . ; ,':'. "'••;•-;••--•
Lower
Floridon
Aquifer
Base of -L-1^-
Floridan Aquifer + 4-
— lnt*rgfonulor Evaporites
fCedar Keys Formation)
LEGEND
Surtktol Deposits
Tempo Member.
Arcadio formation.
Hawthorn Group
Figure 2. Geologic section at the Pinellas STAR Center.
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Hi Nature and Extent of Contamination
The primary contaminant group that the in situ bioremediation technology was designed to treat in this
application was halogenated VOCs at the Northeast Site in the surficial aquifer. Contaminants of concern
(COCs) detected in Northeast Site ground water include 1,1 -dichloroethane, 1,1 -dichloroethylene,
benzene, ethylbenzene, 1,2-dichloroethylene (DCE) (cis and trans isomers), methylene chloride, toluene,
trichloroethylene (TCE), tetrachloroethylene, methyl tert-butyl ether, vinyl chloride, xylenes, and
chloromethane. The major contaminants of concern at this site, because of their concentrations and
cleanup levels are methylene chloride, 1,2-DCE, TCE, toulene, and vinyl chloride. Figure 3 shows a
contour map of VOC contamination in ground water at the Northeast Site and in the area selected for the
bioremediation pilot-study. The concentrations prior to treatment and the solubilities of primary COCs
within selected bioremediation treatment area are summarized in Table 1.
There is some evidence that non-aqueous phase liquid contamination may be present in localized areas at
the Northeast Site. VOC concentrations for several COCs exceeded solubility limits in some of the ground
water samples taken at the site, and the contaminant release scenario (leakage of solvents or resins from
drums stored or buried at the site) is consistent with this type of contamination. While the exact extent and
nature of this contaminant phase is unknown, these areas can be a continuing source of ground water
contamination unless effectively addressed in a comprehensive site remediation system design.
CD
8
\
East
Pond
<9
in situ bioremediation
treatment area
Figure 3. Total VOCs in ground water (in ug/L).
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Table 1. Pretreatment concentrations of contaminants.
Contaminant
TCE
Toluene
cis-1,2-DCE
Methylene chloride
Vinyl chloride
Ground water
Max. cone. (ug/L)
1,700,000
2,200,000
210,000
760,000
130,000
Avg. cone. (ug/L)
46,600
45,600
19,200
18,450
9,500
Solubility limit
(ug/L)e20-252C
1,100,000
515,000
800,000
16,700,000
1,10-1,100,000
^B Matrix Description and Characteristics
The surficial aquifer at this site consists predominantly of saturated beach-type silty sands (see Table 2). A
few lenses of more silty materials exist, though no clay lenses occur in the soil being treated. For these
soils, the hydraulic conductivities in the horizontal direction range from lO^to 10~5 cm/sec, while the
vertical conductivities are approximately 10-100 times lower. The surficial aquifer is highly anaerobic as
demonstrated by the dissolved oxygen and Eh values shown in Table 2.
Table 2. Matrix characteristics affecting treatment
cost or performance.
Parameter
Soil classification
Clay content
Moisture content
Hydraulic conductivity
Khorizontal
Kvertical
Inorganic compounds:
Potassium, soluble
Nitrate/nitrite
Phosphate as P
PH
Total organic carbon
Dissolved oxygen
Eh
Maximum treatment depth:
Saturated thickness treated:
Value
Silty sand
low; 5-10%
mostly saturated (see below)
7x1 0~5 to 2x1 0"3 cm/sec or 0.2-6.6
ft/day;
Kvertical is approx. 10-100 times less
than Khorizontal, or 0.003 to 0.3 ft/day
2-10mg/L
0,2-1 .Omg/L
0.1 -0.5 mg/:
5.5 to 7.2; mean 7.0
4-500 mg/kg; mean 50 mg/kg
0.1-0.8 mg/L; mean 0.1 mg/L
-175 to 30 mV; mean -50 mV
approximately 30 ft
25-27 ft
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4. TECHNOLOGY DESCRIPTION
This field demonstration evaluated in situ anaerobic bioremediation as a technology to treat chlorinated
VOCs in soil and ground water. Bacteria metabolize soluble organic and inorganic compounds to provide
energy for the growth and maintenance of bacterial cells. The complex organic molecules that bacteria
consume are converted to new cells and various simpler compounds, such as carbon dioxide, that are
released back into the environment. This process is referred to as biodegradation. Biodegradation has
been used very cost effectively for more than a century in public and industrial wastewater treatment
systems. Since bacteria occur naturally in both soil and ground water environments, bioremediation
technologies attempt to stimulate the activity of these naturally occurring (or introduced bacteria) to
degrade contaminants in a cost-effective manner. Bioremediation is being considered more often as the
processes that control the biological degradation of contaminants in soil and ground water become better
understood.
•I In Situ Anaerobic Bioremediation Technology Description
In order to produce new bacterial cells, bacteria require carbon, nitrogen, phosphorus, and energy sources,
as well as a number of trace minerals. Electrons are released by the biochemical reactions that
metabolize complex organic compounds for energy. Biological systems capture this biochemical energy
through a series of electron transfer (redox) reactions. The bacteria that are most commonly used in
bioremediation systems use organic compounds as their source of carbon and energy; these carbon
compounds are referred to as electron donors. Bacterial respiration requires that some chemical
compound is available to act as a terminal electron acceptor. Common electron acceptors used by
bacteria include oxygen, nitrate, sulfate, Fe3*, and carbon dioxide.
Recently, a class of anaerobic bacteria has been identified that uses halogenated organic compounds as
their electron acceptors. The chlorinated VOCs present in the soil and ground water at the Northeast Site
are among the halogenated organic compounds that can be used in this manner. Halogenated
compounds have a high oxidation state; and when a halogen (e.g., chlorine) is chemically replaced by
hydrogen, the oxidation state of the chemical is reduced. This process is referred to as reductive
dehalogenation, and it forms the basis of the anaerobic process used by the in situ bacteria at the
Northeast Site. Under anaerobic conditions, chlorinated compounds can be degraded via reductive
dehalogenation reactions to successively lower chlorinated degradation products, and finally to compounds
of significantly lower toxicity. This process is illustrated for TCE below.
TCE * DCE •* VC •» ethylene, ethane
step 1 step 2 step 3
Biological activity is frequently limited by the availability of a single growth factor (e.g. electron acceptor,
electron donor, nitrogen, etc.) and supplying the proper growth factor can often stimulate bacterial growth
and biodegradation rates. For in situ remediation applications, nutrients or electron acceptors are often
injected into the contaminated area to enhance the existing microbial degradation processes. Effectively
delivering nutrients requires that factors such as site permeability and geochemistry be considered. Each
class of contaminant varies in its susceptibility to biodegradation and factors such as aquifer oxidation-
reduction potential, microbial ecology, and contaminant toxicity will affect the success of bioremediation at
a site. The effective application of in situ bioremediation therefore depends upon careful consideration of
the geologic and hydrologic properties at the site and on the type and concentration of contaminants to be
treated. Bench scale treatability studies with aquifer soil and ground water samples are highly
recommended prior to full-scale implementation of most bioremediation projects.
The application of in situ anaerobic bioremediation for the degradation of chlorinated solvents has received
significant interest due to the excellent results obtained in laboratory and small pilot-scale applications
using these processes. These studies have shown that the injection of simple nutrients can
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significantly accelerate the natural degradation of compounds such as PCE, TCE, DCE, carbon
tetrachloride, and methylene chloride in soil and ground water. Some companies hold patents on certain
aspects of accelerated in situ anaerobic bioremediation for the treatment of chlorinated solvents. Sites
interested in the use of this technology should be aware that patent related issues might need to be
addressed
Evaluations of the monitoring data from the Northeast Site suggested that microbial dechlorination is
occurring naturally. DCE and vinyl chloride (VC) are degradation products of TCE that were measured in
high concentrations but were not contaminants originally disposed of at the site, which suggests that a
population of dechlorinating microorganisms is relatively active at Pinellas. Based on these evaluations
and the review of the site hydrologic conditions, it was expected that nutrient injection would be effective in
accelerating the anaerobic microbial degradation of the major COCs at the Northeast Site.
1H Technology Advantages
The treatment of VOC-contaminated soils and ground water using nutrient injection to stimulate and
accelerate in situ anaerobic bioremediation offers the following advantages:
• contaminants are treated in situ with little waste generation,
• contaminant degradation can be relatively fast,
• bioremediation is capable of reducing contaminants to very low levels,
• the process stimulates a microbial population that can continue to feed off the dissolved phase of a
continuing source after nutrient injection ceases, and
• often provides a low overall remediation cost relative to other technologies.
^| Technology Limitations
The treatment of VOC-contaminated soils and ground water using nutrient injection to stimulate and
accelerate in situ anaerobic bioremediation offers the following limitations:
• contaminant degradation enhancement is dependent on adequate nutrient delivery to all areas of
contamination before the nutrients are directly metabolized, which often is primarily a function of site
hydrogeology and the appropriate mixing of nutrients, contaminants, and active microbes,
• site conditions (e.g., soil and ground water chemistry, reductive processes, etc.) must be conducive to
the stimulation of biological activity to be effective,
• bioremediation will not directly degrade contaminants occurring in an immiscible phase,
• high concentrations of contaminants often are toxic to microorganisms,
• bioremediation may be difficult to optimize at sites with multiple contaminants of concern,
• incomplete biodegradation of contaminants can lead to the generation of degradation products that are
just as toxic or even more so than the parent contaminants, and
• regulatory concerns over chemical injections into aquifers.
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•• Treatability Study
Through the ITRD Program, laboratory batch and column biotreatment studies were performed under
anaerobic conditions using aquifer sediments and ground water from the Northeast Site. These studies
were used to assess methods for stimulating and/or optimizing the existing anaerobic biological activity at
the Northeast Site.6 The laboratory studies generated information on contaminant degradation rates, the
reductive dechlorination process, and byproduct formation for several different nutrient combinations and
concentratfons. The nutrient mixtures used included combinations of trace nutrients such as potassium
and phosphorus, and other nutrients such as sodium benzoate, sodium lactate, methanol, and casamino
acids. Nutrient concentrations generally ranged from 100-400 ppm.
The study showed that two nutrient combinations, both of which included methanol, were effective in
reducing both TCE and methylene chloride and that degradation rates of as high as 1-2 ppm/per day were
achievable for TCE. The results also showed that with these nutrient mixtures dehalogenation of TCE did
not stop at any intermediate degradation products. In the case of toluene and trace contaminants, it was
not determined from this laboratory study what conditions would optimize their utilization or degradation.
Under the existing site conditions, toluene can degrade through fermentation, while simple electron
acceptors are available to accelerate toluene treatment.
Based on the laboratory data, a preliminary full-scale bioremediation system cost and performance
estimate was developed. From these engineering estimates, in situ anaerobic bioremediation appeared to
be a very cost effective and rapid technique for treating ground water of low to moderate contaminant
concentration (less than 200 ppm) at the Northeast Site. It was expected that areas of significantly higher
contaminant concentration would probably need to be treated by a more aggressive treatment method.
Pinellas In-Situ Bioremediation System Description
Based on the laboratory treatability study results, and the engineering cost and performance estimates of
in situ anaerobic bioremediation, a large pilot-scale remediation system was designed and constructed at
the Northeast Site. The system was operated for approximately five months to assess the field
performance of this technology and to identify the optimum operating parameters for a full-scale system.
Historical data was used to select an area within the Pinellas Northeast Site that was understood to contain
the entire suite of chlorinated compounds found at the site and with contaminant levels ranging from at
least 100-200 ppm. If the initial concentrations were too high, there was a potential that the microbial
population would be inactive. If the initial concentrations were too low, contaminant degradation could be
difficult to monitor. Thus, an area expected to have mid-range contamination levels, as shown in Figure 3,
was chosen for the in situ bioremediation pilot-study.
The hydraulic modeling, design, construction, and operation of the bioremediation pilot system and the
associated monitoring well network are discussed in detail in this section. The operational concept
developed for the pilot system was to create a closed-loop ground water recirculation system where ground
water could be continually circulated through the treatment area while nutrients were added to the
circulated water to accelerate in situ contaminant degradation. This was expected to minimize external
ground water influence on performance assessment results, minimize nutrient loss and accelerate
biodegradation, and eliminate the need for ground water treatment or disposal. A large number of
clustered monitoring wells were also installed in the treatment area in order to assess contaminant
degradation and system performance throughout all levels of the treatment area.
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Figure 4 shows the general layout of
the treatment area and perimeter and
cluster monitoring wells . Four fully-
screened monitoring wells were
installed in the perimeter of the study
area to perform flowmeter testing of
the aquifer matrix. The flowmeter
testing determined the relative
hydraulic conductivities of the zones
indicated in the cross section in Figure
5. The central area is approximately
45 ft x 45 ft.
The overall design, configuration, and
location of the extraction and injection
wells were developed based on a
number of system performance
assessments using MODFLO, a two-
dimensional ground water flow model.
The modeling looked at nutrient
delivery and movement through the
treatment area based on several
possible vertical and horizontal
system configurations and well
locations and the site hydrogeologic
data. This modeling effort suggested
that ground water circulation using
horizontal wells and trenches would
provide better nutrient delivery across
the horizontal layers of relatively low
PZ-11A(
PZ-11C*
PZ-11B
N
'Z-13B
'PZ-13D
WELLTW-3
WELL TW-2
WELL TW-4
10'
PZ-15A,
PZ-15C
LINE OF
CROSS-SECTION
PZ-14C "PZ-14D
Figure 4. Map of the Pinellas bioremediation area.
vertical hydraulic conductivity where contaminant concentrations were highest.
To achieve a vertical hydraulic gradient, a horizontal extraction well with a 30 foot screened section was
installed through the center of the treatment area in a zone of higher conductivity 16 ft below ground
surface (bgs>. The ground water extracted from the horizontal well was then returned to the aquifer via
one of the four infiltration points shown in Figure 5. The first three points were gravel-filled, surface
trenches (A, B, & C) which were 30 ft long, 8 ft deep, and at least 2 ft wide. The fourth infiltration point (D)
was a horizontal well similar to the extraction well but installed at 26 ft bgs. MODFLOW simulations
indicated that this well and trench system would create a general flow pattern through the treatment area
as shown in Figure 6, under nominal operating conditions. The system was designed to allow reversal of
the extraction and infiltration points, providing flexibility in optimizing nutrient delivery to the different aquifer
levels across the treatment area if ne/eded.
The ground water monitoring system shown in Figure 6 included 16 clusters of 4 sampling points to create
a three-dimensional monitoring network of the treatment area. These monitoring points were installed at
discrete depths starting at the depth corresponding to the elevation of the bottom of the trenches. The "A"
depth was 8-10 ft bgs, the "B" depth was 12-14 ft bgs, the "C" depth was 18-20 ft bgs, and the "D" depth
was 22-24 ft bgs. The "B" and "D" depths were chosen to correspond with the layers of lower hydraulic
conductivity within the study area, which contained the maximum contaminant concentration. This was an
effort to monitor system performance in actual worst case conditions.
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Avg. Kh tt 1.5 ft/doy
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very fine grained, silly,
slightly cloyey
Avg. Kh a 0.2 ft/doy
Kv * .002 fl/doy
-15'
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grained, sUghtly-to-
very slightly silty
Avg. Kh * 6.6 It/day
-20' Kv a 0.7 ft/doy
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grained, slightly silty
-25' '
Avg. Kh it 0.76 ft/day
Kv ».008«/doy
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grained, phospnolic
3Q. A/o. Kh * 10+ ll/dov
, Hawthorn Group
S
Fimirp .R Cross section of treatment area lookina west.
-------
Meters
Tick marks are 10 days on tracks
Figures. MODFLO model of system ground water flow patterns and transit times.
HI Treatment System Schematic and Operation
Figure 7 is the process schematic for operation of the pilot anaerobic biotreatment system. In this system,
the extracted ground water was pumped from the horizontal extraction well, monitored continuously for
contaminant concentrations with an automatic field GC, had nutrients added in-line, and was then returned
to the aquifer through the infiltration trenches and the horizontal infiltration well. The trenches had float
switches installed just below ground surface that operated solenoid valves allowing ground water and
nutrients to enter at a steady rate without overflow. When all three surface trenches were filled to their
recharge capacity, a fourth solenoid valve would open to allow the nutrient rich ground water to enter the
aquifer from the lower horizontal infiltration well in the treatment area.
Each infiltration point was separately metered for flow, and each infiltration point had a separate stock tank
of nutrient solution so that the amount introduced into each point could be calibrated against the
corresponding ground water flow. Total ground water flow through each infiltration point and the nutrient
solution used from each stock tank were recorded daily. The use of individual stock tanks also provided
the capability to conduct a multi-tracer study. The tracers were introduced into the nutrient solution tanks
in a controlled, continuous release so that nutrient transport could be easily monitored. Because both
upward and downward ground water movements were being studied, two different tracers were used.
Bromide was selected for tracking the upward flow from the horizontal infiltration well and iodide was used
for tracking the downward flow from the surface trenches,
An enclosed equipment control pad was located approximately 50 feet east of the system. All nutrient
drums, nutrient pumps, flow meters, solenoid valves, and a filter were located at the control pad.
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Anaerobic In-Situ Bioremediation System
Process Schematic
Control PadJShed)_ |
Horizontal Extraction Well
Horizontal Infiltration Well
0
1
nnn
111111
MUM
nnn
uuy
Flow Meter
Solenoid Volve
Figure 7. Bioremediation pilot system process schematic diagram.
HH Key Design Criteria
The in situ anaerobic bioremediation pilot system was designed for two main objectives:
• develop a nutrient delivery system capable of providing a mixture of nutrients to the subsurface within
the heterogeneous aquifer, such that the nutrients will be delivered to all levels in the treatment area
within an approximately 6-month operating period, and
• create a closed-loop ground water recirculation system that would minimize external influences and
losses and requires no ground water disposal.
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^B Operating Parameters
Operating parameters were adjusted slightly during the pilot test to help optimize operating conditions for
the bioremediation system. The major operating parameters needed to assess the performance and cost
of the bioremediation system were considered to be pumping rates, nutrient concentrations, tracer
concentrations, and well redevelopment frequency. The general operating parameters for the system are
summarized in Table 3.
Table 3. Operating parameters affecting treatment cost or performance.
Parameter
Optimal pumping rate from horizontal extraction well
Optimal pumping rate to infiltration trenches A, B, and C
Optimal pumping rate to horizontal infiltration well (D)
Concentration of methanol added to the ground water
Concentration of sodium benzoate added to the ground water
Concentration of sodium lactate added to the ground water
Concentration of iodide to trenches A, B, and C
Concentration of bromide to horizontal infiltration well (D)
Frequency of redevelopment of horizontal extraction well
Frequency of redevelopment of horizontal infiltration well
Value or Specification
1 .5 gpm
0.2 gpm each
0.9 gpm
60 ppm
120ppm
180ppm
250 ppm
250 ppm
average of once every 3 weeks
once
The horizontal extraction well is located at a depth of 16 feet bgs in a zone of relatively high hydraulic
conductivity. A pumping rate of 1.5 gpm was sustainable through this well. The horizontal infiltration well
was at a depth of 26 feet bgs in a zone of somewhat lower hydraulic conductivity, however, it could accept
a pumping rate of 0.9 gpm of the recirculated ground water under a pressure gradient of 5-10 psi abdve
the ambient hydraulic head. The infiltration trenches are 8 feet deep and located in a zone of lower
hydraulic conductivity. Each trench accepted only approximately 0.2 gpm of recirculated ground water.
Nutrient concentrations added to the ground water were based on the results of the original ITRD
treatment study and follow-on discussions by the ITRD committee.6 Methanol, benzoate, and sodium
lactate, at concentrations of 60,120, and 180 ppm, respectively, were added. This mixture of electron
donors was used to provide nutrients that would be used at different rates by the bacteria in the aquifer to
degrade the major COCs so that the reducing power could be delivered to all treatment levels. Methanol
and benzoate additions were initiated on February 12, 1997 and discontinued on June 30,1997. Lactate
was added from February 27,1997 to June 23,1997. The tracer concentrations added were used to
insure that the breakthrough of nutrient rich ground water could be detected at the monitoring point
locations. Iodide, at a concentration of 250 ppm, was added to trenches A, B, and C. Bromide, at a
concentration of 250 ppm, was added to the horizontal infiltration well (D). All tracer additions were
initiated on March 7,1997. Tracer additions to trenches A, B, C, and well D were discontinued on June 4,
May 13, May 28, and April 25, respectively.
Due to subsurface conditions at the Northeast Site and possible fouling of well screens, redevelopment of
the horizontal wells by hydraulic surging was needed to ensure efficient operation of the system. The
horizontal extraction well was redeveloped on February 24, March 6, March 13, March 31, April 8, April 22,
June 4, and June 16. The horizontal infiltration well was redeveloped only once on June 3,1997.
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•1 5. IN SITU ANAEROBIC BIOREMEDIATION SYSTEM PERFORMANCE
The bioremediation pilot operations at the Northeast Site were conducted to assess the applicability of
nutrient injection to accelerate the degradation of the chlorinated contaminants of concern and to identify
optimal operating parameters. These data were used to determine the expected costs and performance of
a full-scale system at the site.
•I Demonstration Objectives and Approach
The objectives of the pilot in situ anaerobic bioremediation project were as follows:
1. Convert chlorinated VOCs in the ground water at the Northeast Site to innocuous biodegradation
products using in situ anaerobic biodegradation,
2. Determine the suitability and effectiveness of this technology on site soils and ground water, and
estimate the time period needed to meet cleanup objectives,
3. Evaluate the horizontal extraction well and infiltration gallery design configuration for full-scale
implementation and determine hydraulic parameters, such as flow rates, residence times, flowpaths,
and treatment levels,
4. Determine optimal operating parameters and conditions for treatment and potential scale-up, such as
nutrient concentrations, nutrient half-lives, and contaminant degradation rates,
5. Collect sufficient cost data to support cost estimates for a potential full-scale system; and
6. Conduct the pilot test in a location that is representative of site-wide conditions, is not impacted by
neighboring treatment operations (rotary steam stripping) and does not detrimentally impact ongoing
ground water recovery systems.
IHI Performance Evaluation Criteria
The performance criteria considered in evaluating this in situ anaerobic bioremediation system included:
• nutrient transport and utilization in the remediation study area,
• contaminant degradation rates and the reduction in mass of the contaminants,
• fate of chlorinated solvent degradation compounds, and
• levels to which contaminants can be reduced.
The evaluation data were collected by a monitoring program that included: semimonthly sampling for
VOCs, methane, ethane, and ethylene; weekly tracer sampling; semimonthly sampling of nutrients
following tracer breakthrough; weekly measurements of water levels until ground water flow conditions
stabilized; and maintenance of a daily log to record operational data.
•i Performance Summary
Table 4 summarizes the pretreatment (February 1997) and post-treatment (July 1997) contaminant
concentrations at each of the 64 monitoring points within the bioremediation treatment area, as well as the
period of time required for the nutrients to reach each monitoring point. The conceptual model of this
mlcrobially mediated, in situ, reductive dechlorination system requires that nutrients (primarily electron
donors), contaminants, and adapted microorganisms reside or mix at the appropriate ratios and
concentrations for significant contaminant reduction to occur.
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CO
CO
oo
Table 4. Pretreatment and post-treatment contaminant concentration at the Pinellas Plant in situ bioremediation treatment area.
Time to nutrien
Well # breakthrough
in weeks
1A 10
1B 12
1C
1D 4
2A 11
2B 10
2C 12
2D 4
3A 14
3B
3C 14
3D 5
O 4A 10
8 4B 10
B 4C
o. 4D 7
§• 5A 10
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Toluene
before after decline
47 58 -23
ND 13
ND <1.0
310 310 0
1,600 130 92
100 700 -600
210 <10 96
2,200 400 82
190 1100 -479
1,900 12000 -532
9,800 7500 23
1,900 1500 21
3,600 3500 3
190,000 74000 61
4,800 20000 -317
7,800 16000 -105
470 62 87
1,400 3000 -114
130 590 -354
1,500 1700 -13
17 15 12
440 2500 -468
530 1400 -164
2,800 980 65
2,000 160 92
250 2100 -740
100 1300 -1200
1,600 1600 0
2,300 4000 -74
71,000 100000 -41
150 840 -460
2,400 940 61
Methylene Chloride
before after decline
ND <5.0
ND <5.0
ND <5.0
ND <25
ND <10
ND <50
ND <50
1,400 <50 96
ND <250
ND <1200
1,500 <1000 33
3,800 <250 93
ND <1200
25,000 <25000
ND <5000
ND <2000
ND <25
ND <500
ND <250
3,300 <120 96
ND <5.0
ND <120
680 <1000
ND <120
49 <10 80
ND <120
ND <100
ND <120
810 <500 38
190,000 190000 0
140 <100 29
2,900 <100 97
TCE
before after decline
ND <1.0
ND <1.0
ND <1.0
ND <5.0
ND <2.0
ND <10
ND 110
420 <10 98
ND <50
ND 370
280 <200 29
560 <50 91
ND <250
210,000 20000 90
ND <1000
ND <400
ND <5.0
1,400 730 48
ND <50
560 <25 96
ND <1.0
440 320 27
230 <200 13
ND <25
ND <2.0
600 200 67
ND <20
ND <25
ND 1900
160,000 240000 -50
ND <20
370 <20 95
cis-1,2-DCE
before after decline
ND <1.0
220 <1.0 99
ND <1.0
630 <5.0 99
ND <2.0
ND <10
ND 450
4,200 <10 99
31 <50
1,900 21000 -1005
6,600 1500 77
1,900 <50 97
260 <250
96,000 110000 -15
4,200 2500 40
ND 4700
ND <5.0
860 1700 -98
9 67 -644
1,600 140 91
ND <1.0
25 430 -1620
800 16000 -1900
4,600 48 99
14 4 71
ND 1200
31 250 -706
3,600 59 98
350 3400 -871
210,000 170000 19
120 59 51
3,800 68 98
Vinyl chloride
before after decline
ND <1.0
880 16 98
22 54 -145
640 <5.0 99
83 <2.0 98
16 <10 38
12 990 -8150
3,500 <10 99
240 <50 80
11,000 14000 -27
11,000 4100 63
2,700 150 94
490 <250 50
37,000 12000 68
12,000 6500 46
ND 3700
ND <5.0
1,500 260 83
58 57 2
1,800 68 96
ND 14
52 55 -6
840 14000 -1567
3,400 31 99
67 50 25
150 1400 -833
94 280 -198
4,600 43 99
700 1300 -86
38,000 20000 47
320 63 80
4,500 43 99
Total chlorinated VOCs
before after decline
18 37 -104
1,100 37 97
22 56 -156
1,270 195 85
113 13 89
27 15 44
12 1,550 -12817
9,520 0 99
291 0 99
12,900 35,370 -174
19,380 5,600 71
8,960 204 98
750 0 99
368,000 142,000 61
16,200 9,000 44
0 8,400
0 9
3,890 2,690 31
117 124 -6
7,260 208 97
0 18
517 805 -56
2,580 30,000 -1063
8,000 79 99
152 69 55
750 2,800 -273
125 530 -324
8,200 102 99
1,860 6,600 -255
598,000 620,000 -4
580 122 79
11,570 111 99
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Cost and Performance Report - Pinellas In Situ Anaerobic Bloremediation
202
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Due to the nature of the subsurface hydrogeology, transport and mixing times for the added nutrients will
vary across the site, and depending on system design and operation, nutrient delivery to some portions of
the aquifer could require significant amounts of time. Therefore, good system performance often requires
nutrients that will not be consumed immediately at an injection location and can be transported quickly and
efficiently through the subsurface to all levels of the treatment areas.
System Hydraulics and Nutrient Fate and Transport
At the pumping rate of 1.5 gpm, approximately 250,000 gallons of water, or about two pore volumes, were
recirculated through the pilot study treatment area over a five-month period. Tracers were used to identify
nutrient breakthrough at each monitoring point for the first ten to twelve weeks of system operations.
When over 50% of the monitoring points showed breakthrough, tracer additions were stopped and nutrient
concentrations were monitored directly. Tracer and nutrient breakthrough were defined as a concentration
greater than 10% of the injected concentrations. Tracer breakthrough was observed earliest (1-2 weeks)
in several of the "D"-level wells in the central part of the treatment area. The "B" and "C" level wells
showed much slower tracer and nutrient breakthrough and the perimeter wells (Wells 9,10,11, and 14)
showed limited breakthrough during operations. Of the 48 central monitoring points, 43 wells (90%),
experienced breakthrough during the first 16 weeks of operation. Of the wells showing breakthrough in the
central treatment area, 77% did so in the first two to three months of system operation. Overall, Levels A,
B,' C, and D had 88%, 81%, 81%, and 100% respectively, of their monitoring points during the first 16
weeks of operation. These results suggest that though some of the recirculated water may have escaped
from the treatment area in levels A and D, water was effectively circulated within the central treatment area
of the pilot system.
The tracer and nutrient breakthrough observations were consistent with model predictions. Based on initial
modeling with a flow rate of 2 gpm, it was expected that nutrient delivery to the "B" level could take three to
four months. It was hoped that this flow rate could be achieved from the extraction well, though a flow of
only 1.5 gpm was sustained. A higher flow rate might have improved nutrient delivery to the "B" level
monitoring points. From field observations, it appears that the extraction well efficiency was reduced in
part due to borehole skin effects caused by the drilling fluid used during installation. BioboreTM by Baroid
was used by the drilling contractor and appears not to have degraded as well as expected. Additionally,
the infiltration trenches accepted a smaller volume of water than was initially expected, which in turn limited
nutrient delivery into the "A" and "B" level monitoring points.
Since enhanced bioremediation depends on adequate nutrient delivery, bioremediation at this site will be
controlled by the rate at which nutrients can be delivered into the middle and identified lower permeability
zones. This is one reason why the two horizontal well system was implemented, since it allows for
reversing the injection and extraction wells and providing more flexibility in delivering nutrients to all levels
in the aquifer. However, in order to minimize complications in evaluating the operational performance of
the pilot system, reversing the operation of the two horizontal wells was not exercised during the pilot
operations. Based on the results of this pilot study, it appears that a properly designed and operated
system can deliver nutrients to all of the aquifer at this site within six to eight months.
Nutrient Fate Assessment
For this pilot study, a mixture of electron donors was selected based on the consideration that the relative
degradation rates for the different compounds would allow for the delivery of the reducing power of the
nutrients to be spread throughout the treatment system. Lactate was used because it is a readily available
carbon source that should be quickly oxidized to acetate, which is expected to degrade much slower.
Benzoate was expected to degrade slower than lactate but would also yield partial oxidation products such
as acetate that again should take longer to degrade. Methanol was expected to degrade slower than
lactate, but faster that benzoate, while also acting as an electron donor to accelerate biodegradation of
methylene chloride.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
203
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During system operations, sodium benzoate was detected in 59 monitoring points. Of these, 5 had
reported concentrations higher than the initial feed concentrations and were not included in the
calculations. Using the remaining 54 data points, the average half-life of the nutrients in the aquifer were
calculated to be about 110 days, with the calculated half-lives ranging from 12 to 949 days. The 110-day
nutrient half-life should be considered a minimum in that dilution, dispersion, and retardation effects were
not accounted for due to the difficulty in assessing their relative contributions to the observed concentration
decreases.
Similar calculations for lactate proved even more difficult due to the inability to resolve lactate/acetate
contributions in the analytic methods used. It should be noted, however, that the observed concentrations
at several locations in the pilot study area yielded lactate/acetate concentrations near or even above the
initial lactate injection concentration of 180 mg/l. This suggests that lactate/acetate half lives in this system
of a year or more are possible or that benzoate was being metabolized to acetate. The methanol
concentrations varied widely across the treatment area. At some points, methanol concentrations in
excess of ten times the added concentration were reported. This suggests that components in the ground
water may have interfered with the laboratory analysis.
Together, these results suggest that the nutrients necessary to enhance bioremediation at this site were
successfully delivered to areas reached by the injected water. The detection of significant concentrations
of benzoate, methanol, and lactate/acetate throughout the treatment at the end of the pilot system
operation suggests that the bioavailable reducing power from the injected nutrients were not a limiting
factor for this pilot effort and should not be a limiting factor in the operation of a properly designed full-scale
system. Based on the system operation, nutrient delivery can be expected to occur in all areas of the
aquifer including the middle and lower permeability areas within the effective half-lives (four months to a
year) determined for these nutrients.
Contaminant Degradation and Reduction Rates
Contaminant levels encountered at the different monitoring points within the treatment area generally
ranged from 10 to 400 ppm total chlorinated VOCs, with one monitoring point location in Level "B" had a
concentration of about 2900 ppm. The bioremediation system at this site was designed to develop a
recirculation cell within the aquifer creating complex, three-dimensional, ground water and contaminant
mixing, making the evaluation of system performance more complicated. Because of the mixing and
recirculation of the ground water, temporal variations in contaminant levels in individual monitoring points
could be expected. Therefore, it was important to look at contaminant reductions across the whole site, at
various treatment levels, at individual wells, and in the extraction well to help assess system performance
and define actual contaminant reductions due to biological treatment.
As shown in Table 4, in the wells where nutrient breakthrough, chlorinated VOC concentrations were
commonly observed to fall by 60%-99% from their pretreatment levels in as little as four to eight weeks
after nutrient arrival. In wells with at least six weeks of nutrient availability, TCE was reduced by 94%, DCE
by 54%, vinyl chloride by 58%, methylene chloride by 60%, and toluene by 80%. In wells where nutrient
breakthrough was not evident or of short duration, there was a reduction of only 10-15$ in total chlorinated
VOCs and toluene. These results suggest that though contaminant reduction in part is probably the result
of ground water mixing and contaminant redistribution, contaminant reduction is significantly greater in
wells where nutrients are available. Likewise, because of the ground water recirculation, increases in
contaminant levels in some wells should be expected. Contaminant increases were observed primarily in
wells with lower (~1 ppm) concentrations. Many of the increases observed were for DCE or VCE, which is
consistent with the reductive dechlorination process. Significantly fewer concentration increases were
observed for TCE and methylene chloride in the wells with long term nutrient availability.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
204
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Figure 8 shows two wells, Well 2D and Well 4B, that are located in the central treatment area and provide
a range of the observed monitoring well data. Well 2D is a low concentration well with very little TCE that
is near the horizontal recirculation well. Nutrient arrival occurred shortly after nutrient addition as shown by
the tracer concentration data measured. Well 4B has a much higher concentration of TCE and is in the
lower permeability zone where nutrient breakthrough took much longer, approximately two months, and the
level of nutrients delivered to this area was probably lower, as evidenced by the much lower tracer
concentrations. The results for Well 2D are representative of many of the "D" level wells, showing a
reduction of the chlorinated contaminants to regulatory levels in several weeks. Both DCE and vinyl
chloride were reduced at a rate of 0.10-0.20 ppm per day. Since toluene was not specifically targeted for
biological degradation, toluene was monitored to assess contaminant reductions attributable to mixing and
redistribution. Over this period, toluene levels changed slightly while ethylene increased substantially,
suggesting that anaerobic reductive dechlorination was the major mechanism for contaminant reduction.
The results for Well 4B are typical of many "B" level wells, showing a much longer period for nutrient
delivery and contaminant reduction than Well 2D. This is in part due to the much higher contaminant
concentrations. The reductions in contaminant levels, including toluene, is similar until late in the
operations where TCE continues to decrease and DCE begins to increase. The initial TCE reduction rate
observed after nutrient arrival is over 2 ppm per day and as the TCE concentration approaches 0.2 mmol/L
(25ppm), the degradation rate slows to 0.10-0.20 ppm per day observed in Well 2D.
In evaluating the monitoring data from all wells showing early to mid-period nutrient arrival, contaminant
reduction rates of 1-2 ppm per day were observed for the high (above 200 ppm) contaminant levels to
approximately 0.05-0.20 ppm per day for wells with contaminant levels of less than 20 ppm. These rates
suggest that areas with moderate TCE contamination would require one to two months after nutrient arrival
to reduce TCE to levels of 5-10 ppm and another one to two months to reduce the TCE to regulatory
levels. The further reduction of the DCE and vinyl chloride produced to ethylene could take similar periods
of time. This suggests that as much as a year may be necessary for areas of high contaminant
concentration to be reduced to regulatory levels for all contaminants following nutrient availability.
Figures 9 and 10 show contaminant reduction trends by level for toluene, TCE, DCE, and vinyl chloride and
the production of ethylene for the wells in the central treatment area that received nutrients. Since the
monitoring points in each level do not receive nutrients at the same time, a classic step-wise dechlorination
sequence was not expected. Each level was analyzed separately in an effort to identify trends in
contaminant distribution and biological degradation. Similar to the results of Figure 8, contaminant
reduction at each level begins as the wells receive nutrients. Level D, where most of the wells have
nutrient arrival very early during system operation, is the only level where measurable ethylene production
occurred. Level A, where nutrient arrival was longer, reductions in DCE and corresponding increases in
vinyl chloride are observed. In Levels B and C, which have much higher contaminant concentrations and
much shorter periods of nutrient availability, show much slower overall contaminant reductions. The
contaminant reduction results in Levels B and C are overshadowed by the data from several monitoring
points with high contaminant concentrations that had nutrient breakthrough in only the last four to five
weeks of system operation. Contaminant reduction in the wells in these two levels with longer nutrient
availability show more pronounced contaminant reductions as shown in
Table 4.
Contaminant Reduction Levels
Thought the pilot system was not designed nor operated to meet any specific cleanup criteria during the
short operational period, final contaminant levels for many monitoring points were measured below 50-100
ppb, while several of the lower concentration wells had contaminant concentrations reduced to below 5
ppb. The data also show that monitoring points with individual contaminant concentrations above 5-10 ppm
were not reduced to allowable levels during the pilot operations. This data, along with the degradation rate
results discussed above, suggests that though contaminant degradation is rapid once nutrients are
available, the operational period of a bioremediation system could be controlled by degradation rates at the
lower contaminant levels.
April 1998
Cost and Performance Report - Plnellas Plant In Situ Anaerobic Bioremediation
206
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•o
3.
Total Concentration in mmol/L In Central Wells with
Nutrient Arrival
Total Concentration in mmol/L. in
Central Wells with Nutrient Arrival
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Number of Central Wells with Nutrient Arrival
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LEVEL C
6 8 10 12 14
Weak» After Start of Nutrient Addition
18
20
LEVEL D
—I 16
6 8 10 12 14
Weaki After Start of Nutrient Addition
16
18
20
April 1998
Figure 10. Contaminant monitoring data for Level C and D Wells.
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediatlon
208
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Extraction Well Monitoring Data
In addition to the 64 monitoring point, the extracted ground water was monitored every two hours using an
in-line, automated, gas chromatograph (GC). The system was continuously calibrated using a prepared
standard. The data were compared with GC data from grab samples collected from the well. Both sets of
data and were shown to be within the accuracy limits of the two instruments. The average daily data,
shown in Figure 11, provide additional evidence of the biodegradation occurring in the subsurface and the
overall rates of contaminant reduction. In general, the extracted ground water trends and the data from the
monitoring points in the interior of the treatment zone correlate well. Contaminant reduction in the ground
water began to occur rapidly in mid-April, which is the time when approximately half of the monitoring wells
that would experience nutrient arrival had done so. Contaminant reduction continued throughout system
operations, but was much slower as additional wells experienced nutrient arrival. The sharp increases in
the contaminant concentrations and the data gaps shown for the GC generally correspond to
redevelopment of the extraction well, which occurred as discussed previously on February 24, March 13,
March 31, April 8, April 22, June 4, and June 16. This automated monitoring system worked well during
the pilot operations and appears to be a simple method that can be used to guide operations and define
sampling events of a full-scale bioremediation system.
Note: Data gaps are periods when
the GC was not operational
DATE
Figure 11. Continuous monitoring data of the extracted ground water.
Reduction of Other Contaminants
Table 4 and Figures 8-11 support the observation that across the site, enhanced bioremediation occurred
as a result of system operations. As discussed, the pilot operations were designed to optimize conditions
for the reduction of the chlorinated contaminants and were not optimized to reduce toluene. Though
toluene concentrations decreased over much of the site, residual toluene levels will have to be addressed
in a full-scale system design. This may require the addition of a different nutrient mix at some point during
operations, though oxygen injection is often used to quickly, and effectively reduce toluene concentrations
to regulatory levels.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
209
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A summary of the performance of the in situ anaerobic bioremediation pilot system is provided in Table 5,
relative to the performance measures and objectives. Overall, the system met most of the identified
system performance objectives.
Table 5. Bioremediation system performance summary.
Performance Evaluation Criteria
Treatment volume:
Ground water treated:
Extraction/reinjection rate:
System nutrient transport effectiveness:
Level A -8-10 feet deep
Level B - 12-14 feet deep
Level C - 18-20 feet deep
Level D - 22-24 feet deep
Nutrient effectiveness:
Nutrient viability
Contaminant degradation rates:
>100 ppm concentration levels
1-10 ppm concentration levels
Reduction values for contaminants of concern:
Toluene
TCE, DCE, vinyl chloride, methylene chloride
Chlorinated solvent by-product production
Waste Generated
Achievable contaminant reduction levels:
Values/ Results
Approximately 45 ft x 45 ft x 30 ft, 60750 ft3
Approximately 250,000 gallons, about 2 pore volumes
Approximately 1 .5 gpm
Nutrients were effectively distributed to approximately
90% of the central monitoring points in 23 weeks,
Nutrients delivered to 88% of the monitoring points
Nutrients delivered to 81% of the monitoring points
Nutrients delivered to 81% of the monitoring points
Nutrients delivered to 1 00% of the monitoring points
Significant reductions in all contaminants occurred
within 4-8 weeks after nutrient arrival at a well point
Average nutrient half-life of 1 10 days, up to > 1year
1-2 ppm per day
0.05-0.10 ppm per day
50-70% within 4-8 weeks of nutrient arrival
90-95% within 4-8 weeks of nutrient arrival
General decline in all contaminants with some
temporary increases in degradation products, followed
by reduction of the degradation products themselves
by biological degradation.
None, all extracted ground water was recirculated
Many contaminants were reduced to the 50-1 00 ppb
level, the detecton limit for most analyses. Some
monitoring points with concentrations less than 10
ppm were reduced to <5 ppb.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
210
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6. IN SITU AN AEROBIC BIOREMEDIATION SYSTEM COST
The Pinellas in situ anaerobic bioremediation project was constructed and operated by Lockheed Martin
Specialty Components (LMSC) under their cost-plus-fee management and operations (M&O) contract with
DOE. Several organizations, including the EPA National Risk Management Laboratory, Sandia, FDEP,
and several industry participants, played an important role in the design, operation, and monitoring of the
remediation system. These services were often in an advisory or consulting role, though some direct
support was provided to the project. For example, FDEP provided three-dimensional graphical data of
sampling results on the Internet for use by the ITRD participants. Where appropriate, direct support costs
are included in Table 6, which shows project costs in accordance with the interagency work breakdown
structure adopted by the Federal Remediation Technologies Roundtable.
Table 6. Bioremediation Project cost by interagency work breakdown structure.
Cost element
(with interagency
WBS Level 2 code)
Mobilization and preparatory
work(331 01)
Monitoring sampling, testing,
and analysis (331 02)
Ground water collection and
control (331 06)
Biological Treatment (331 11)
General requirements (331 22)
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Description
Four, fully-screened vertical wells at corners of
treatment area
Flow model calibration and analysis
Flow meter testing
Monitoring point network
Pre- and post-treatment coring
Laboratory - VOCs (biweekly)
Laboratory - methane, ethane, ethylene
(biweekly)
Laboratory - tracers (biweekly)
Iodide tracer
Laboratory - nutrients (weekly)
Bromide tracer
Labor
Horizontal well installation
(2-240 feet long w/30 feet screens)
Pumps and controls
Trenches
Plumbing, utilities, pad, shed, etc.
Operations labor
Methanol -60 kg
Sodium benzoate -120 kg
Sodium lactate (2 drums) -1.70 kg
Bromide
Utilities: Electricity
Project management and engineering
r~ " V "A \ > "*" , +f %
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Costs
($)
$ 1 0,000
$ 15,000
$ 10,000
$ 15,663
$ 20,000
$ 48,728
$ 81,900
$ 9,492
$ 2,568
$ 8,860
$ 869
$ 40,230
$ 41,235
$ 9,256
$ 7,925
$ 29,120
$ 19,440
$ 174
$ 376
$ 3,483
$ 869
$ 275
$ 12,480
TOTAL
Subtotals
($)
$ 35,000
$ 238,310
$ 87,563
$ 23,748
$ 12,480
$ 397,074
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
211
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As discussed earlier, the goal of the operation of this in situ anaerobic bioremediation pilot system was to
assess the ability of nutrient injection to accelerate the reduction of contaminants at the Northeast Site and
to identify optimum operating conditions for the design and operation of a full-scale system. Since the pilot
system was not operated to meet any specific cleanup criteria and the treatment area selected had
nominal contaminant levels higher than much of the Northeast Site, it would be inappropriate and possibly
misleading to specify a direct treatment costs for a full-scale system implementation. However, general
observations and estimates of biological treatment capital and operating costs can be made.
As can be seen from Table 6, almost two-thirds of the overall costs qf the pilot operation were related to
the extensive monitoring conducted. This level of monitoring was used in an effort to better understand the
operation of the pilot system and to track the biodegradation occurring at different levels in the aquifer. As
extensive a monitoring system and the associated costs would not be required in a full-scale system. The
monitoring costs data provided though does show how systems like the continuous monitoring field GC
can be used to provide significant bioremediation data at a low cost. Typical fully automated continuous
monitoring systems like the one used at Pinellas are available for less than $50K.
From an operational viewpoint, the pilot system pumped approximately 250,000 gallons of water, this
allowed for treatment of approximately two pore volumes of contaminated ground water in the central
treatment area. The direct biological treatment costs for water treatment during the pilot operations were
therefore approximately $0.10-0.12 per gallon of water treated. Since additional treatment would be
required to reduce contaminants to regulatory levels in some areas, these costs are only approximate.
Actual costs will vary based on the contaminant levels and the hydrogeology encountered across the site,
though much of the site has significantly lower contaminant levels than the pilot study area.
The system construction, operations labor, and chemical costs are often proportional to the scale of a
project and can be more easily used to quantify potential full-scale system operating and construction
costs. Initial estimates of the construction and operating costs of an in situ anaerobic bioremediation
system were developed by the ITRD Program based on site hydrogeologic data and the results of the
biodegradation treatment study.7 The initial estimates were developed by two, environmental consulting
firms familiar with implementing bioremediation systems. They estimated that a vertical well based
treatment system would take approximately a year to construct, require about a year to deliver nutrients to
all areas of the site, and about six months to a year for contaminant degradation, for a three to four year
total remediation period. The nutrient costs were estimated to be about $750K, with system operational
costs of $600K per year. Capital costs for a ground water extraction and recirculation system were
estimated at $2M, for an estimated total site remediation cost of $3.5-4.5M. These cost estimates
assumed application of a bioremediation system in the areas of low to moderate concentration (less than
200 ppm), while the higher contaminant levels would be treated with another more aggressive technology.
The performance of the pilot system generally substantiated many of the initial performance and unit cost
assumptions and related overall cost estimates. Based on the pilot data, it appears that it would take about
6-8 months to get nutrients to all levels of the aquifer and another 8-12 months for contaminant
degradation and reduction in all levels to regulatory limits, or about two years for system operations. Based
on nutrient costs and the levels used for the pilot and two year operational period, nutrient costs for
treatment of the three to four-acre Northeast Site would be about $750K to $1M, depending on the savings
of buying nutrients in bulk quantities. Scaling of the construction costs of the horizontal pilot-system for
application to the entire Northeast Site suggest a full-scale cost of approximately $3-4M. These results
suggest that a full-scale bioremediation system based on a horizontal extraction and recirculation design
would cost $4.5-5.5M to construct and operate for a two to three-year period. The required operational
period and associated costs for some portions of the system might be reduced since much of the
Northeast Site has nominal contaminant levels of 10-30 ppm, rather than the higher contaminant levels
observed in the selected pilot-system treatment area.
April 1998
Cost and Performance Report — Pinellas Plant In Situ Anaerobic Bioremediation
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7. REGULATORY/INSTITUTIONAL ISSUES
In July 1993, DOE, EPA, FDEP, and LMSC entered into an agreement with the ITRD Program to evaluate
innovative technologies to remediate ground water contamination at the Pinellas STAR Center Northeast
Site effectively and expeditiously.
Under Section II.D.1 of the Department of Energy's HSWA Permit, interim measures may be conducted at'
SWMUs after EPA approval. Section II.D.3 requires the permittee to notify the EPA Regional
Administrator, as soon as possible, of any planned changes, reductions, or additions to the interim
measures. The proposed in situ anaerobic bioremediation project would temporarily interrupt the operation
of the existing interim measures (pump and treat with air stripping); therefore, the DOE provided notice to
the EPA and FDEP of a planned change (the implementation of ITRD field activities) to the approved
interim measures and proposed implementation schedule for concurrence in August 1996. Authorization
for implementation of the activities was received in August 1996.
Initially, both industry and regulatory participants of the ITRD committee were concerned that underground
injection control (UIC) requirements may prevent the recirculation of ground water. Through assistance
from the FDEP, discussions were held with the State of Florida, who has UIC delegation, about this issue
Because of the system design (i.e., in situ recirculation) the state determined that no UIC permit was
required.
Figure 12 shows the tasks and schedule associated with the in situ anaerobic bioremediation project at the
Pinellas STAR Center.
Task Hume
Start
1997
i IAua ISeo I Pet I Nov I Doc I Jan I Feb I Mar I Apr I May I Jun I Jul I Aug I
11
12
14
15
17
18
•kpt
mpl.
8/1/96
an/96
System construction
8/1/96
11/8/96
Install horizontal weRs
8/19/96
8/22(96
InstaB infiltration trenches
313135
9fl7/96
Install monitoring network
9/26/96
10/1/96
System checkout & hydraulic tests
10/1/96
12/20/96
System operation
2/10197
6/27/97
Reclrculate ground water
2/10/97
6/27/97
Add methancl & benzoate
2/12/97
6/27/97
Add lactate
2/27/97
6/23/97
Conduct tracer study
3/7/97
6/4/97
Add Iodide to trenches
3/7/97
Add bromide to lower horiz wefl
1/25/97
Groundwater sampling
7/9/97
Pretreatment VOC sampling
11/8/96
Operational VOC sampling
2/17/97
7S/97
Methane, Ethane, Ethene sampfe
314137
7/9/97
Tracer sampling
3/7/97
7/7/97
Nutrient sampling
5/8/97
7/9/97
Figure 12. Bioremediation project schedule.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
213
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•I 9. OBSERVATIONS AND LESSONS LEARNED
•I Cost Observations and Lessons Learned
Based on the construction and operating treatment cost data from the pilot system operation, it appears
that in situ anaerobic bioremediation is a cost-effective method for reducing chlorinated VOCs in
subsurface environments, given favorable geochemical, microbal, and hydraulic/hydrologic characteristics,
such as at the Pinellas Northeast Site.
HI Performance Observations and Lessons Learned
Laboratory batch and column studies, using site soil and ground water, if used correctly can help identify
whether a population of anaerobic microorganisms exists capable of remediating the contaminants of
concern at a site and which nutrients can enhance degradation of those contaminants.
Good nutrient distribution is critical to effectively enhancing contaminant degradation in a treatment area.
Therefore, a thorough and detailed understanding of the site hydrology is necessary to design an effective
nutrient delivery system. Flow meter field testing and numerical modeling should be used to help identify
the best nutrient delivery system for a site.
The recirculation system of infiltration trenches and two horizontal wells developed for this site proved
effective in the pilot operations. Because of the recirculation design, no waste water was generated.
Improvements, such as deeper surface trenches and the flexibility of switching extraction and injection
roles of the horizontal wells, could accelerate nutrient delivery to the middle and lower permeability layers
and overall remediation of the site. Effective redevelopment of long horizontal wells can sometimes be
difficult and should be considered in the overall design and operation of a full-scale system.
At monitoring points were nutrient breakthrough was observed for at least four to eight weeks, significant
declines in total chlorinated VOC concentrations (70-95%) were generally observed. These values
correlate well with the results from the extraction well. For those wells where nutrient arrival was not
observed, generally in the areas of lower permeability or in perimeter wells, only modest contaminant
reductions were recorded. Though the nutrient mixture and concentrations were not specifically optimized
during pilot operations, degradation rates as high as 1-2 ppm per day were observed in higher
concentration areas (>100 ppm), while in areas with lower concentrations degradation rates ranging from
0.05 to 0.10 ppm per day were observed. It is possible that the nutrient mixture might be adjusted to
further accelerate contaminant reduction. There was little evidence of significant degradation product
buildup at monitoring wells after nutrient arrival.
Contaminant degradation observed in the pilot study at concentrations higher than 200 ppm suggests that
anaerobic bioremediation is more robust and has a broader operational capability than previously
identified.
Hi Summary
The extensive modeling and hydrogeologic, nutrient transport, and operating cost data developed during
the pilot system operation suggest that nutrient addition to stimulate in situ anaerobic biological
degradation of chlorinated solvent contaminated soil and ground water is a feasible, cost-effective,
remediation approach at the Pinellas Northeast Site for areas of moderate contamination. The limiting
factors for successful, cost-effective implementation are the ability to deliver appropriate nutrients to all
contaminated areas and hydraulic travel times.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
214
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• 10. REFERENCES
1, Installation Assessment, Pinellas Plant, U.S. Department of Energy, Comprehensive Environmental
Assessment and Response Program, Albuquerque Operations Office, Albuquerque, N.M., 1987.
2. RCRA Facility Investigation Report, Pinellas Plant, U.S. Department of Energy, Environmental
Restoration Program, Albuquerque Operations Office, Albuquerque, N. M., 1991.
3. RCRA Hazardous and Solid Waste Amendments Permit, U. S. Department of Energy Pinellas Plant,
Largo, Florida. EPA ID No. FL6-890-090-008, U.S. Environmental Protection Agency, February 9,
1990.
4. Interim Corrective Measures Study, Northeast Site, TPA2 6350.80.01, prepared by CH2M Hill for the
U.S. Department of Energy and General Electric Company, Neutron Devices Department, Largo, FL,
May 1991.
5. Corrective Measures Study Report, Northeast Site, Pinellas Plant, Largo, Florida, U.S. Department of
Energy, Environmental Restoration Program, Albuquerque Field Office, Albuquerque, N.M., 1993.
6. Flanagan, W.P., et al. "Anaerobic Microbial Transformation of Trichloroethylene and Methylene
Chloride in Pinellas Soil and Ground Water," General Electric Corporate Research and Development
Center, Schenectady, NY, May 1995.
7. Pinellas Northeast Site Project, Innovative Technology Review, letter to David Ingle, U. S. Department
of Energy, from Mike Hightower, Sandia National Laboratories, Februarys, 1995.
April 1998
Cost and Performance Report - Pinellas Plant In Situ Anaerobic Bioremediation
215
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r
11. VALIDATION
Signatories:
"This analysis accurately reflects the performance and costs of the remediation."
DavW S. Ingle, ER Program Manpger
U.S. Department of Energy
Grand Junction Office
"WCJL
Mike Htghtower, Tdfchnfcal Coordinator
Innovative Treatment Remediation Demonstration Program
Sandla National Laboratories
GuySewel, Research Mlcrobfologist
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
April 1998
Cost and Performance Report - Plnellas Plant In Situ Anaerobic Bloremedlation
216
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Lawtan Chiles
Governor
Department of
Environmental Protection
Twin Towers Building
2600 Blair Stone Road
Tallahasseo, Florida 32399-2400
April 14,1998
Virginia B. Wetherell
Secretary
Mr. David Ingle
c/oMACXEC-ERS
7887 Brian Dairy Road
Suite 200
Largo, Florida 33777
Dear Mr. Ingle:
I have reviewed the "Cost and Perfonnance Report, In Situ Anaerobic Bioremediation, Pinellas
Plant Northeast Site" final draft dated March 16,1998. I concur with the purpose of the report. Unless
the EPA or other parties desire modifications, we recommend that the report proceed to "final"
designation.
If I can be of any further assistance with this matter, please do not hesitate to contact me at
904/921-9983.
Sincerely,
John R. Armstrong P.O.
Remedial Project Manager
/¥
Date
CC:
JJC
Cheryl Walker-Smith, USEPA Atlanta
Satish Kastury, FDEP
ESN15X/
"Protect. Conserve and Manage Florida's Environment and Natural Resources"
Printtd on recycled paptr.
217
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA FEDERAL CENTER
61 FORSYTH STREET, SW
ATLANTA. GEORGIA 30303-8909
APR 2 6 1938
4WD-FFB
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
The United States Department of Energy
Pinellas Plant
ATTN: Mr. David Ingle
P.O. Box 2900
Largo, FL 34649
SUBJ: Revised Cost and Performance Report: In Situ Anaerobic Bioremediation
Pinellas Northeast Site, Largo, Florida
Final Draft - March 16,1998
DOE Pinellas Plant, FL
EPA LD. Number FL6 890 090 008
Dear Mr. Ingle:
The Environmental Protection Agency (EPA), Region 4, has completed our review of the
revised Cost and Performance Report for the in situ anaerobic Bioremediation project conducted
at the Northeast Site (Solid Waste Management Unit PIN 15). This work was conducted under
the Innovative Treatment Remediation Demonstration (ITRD) agreement between EPA Region
4, the Florida Department of Environmental Protection (FDEP), the U.S. Department of Energy,
Clean Sites, Inc., the EPA Technology Innovation Office, and Sandia National Laboratories.
This team's mission was to identify and demonstrate various innovative technologies applicable
to this and other contaminated waste sites around the country. This is the third innovative
technology demonstration conducted at the Northeast Site.
This project utilized the experience and expertise of personnel from the EPA National
Risk Management Research Laboratory (NRMRL) and Lockheed-Martin in the design,
construction, implementation, and sampling efforts. The FDEP participants played a key role in
system design, permitting issues, and computer support. The facilitator of the ITRD effort, Mr.
Mike Hightower, deserves special credit for unifying and focusing the efforts of this team, and in
the overall success of this ITRD project.
Prfnl«dw»hV*^^
218
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The EPA approves of the changes made in this revised document and looks forward to
the possibility of other ITRD projects occurring across Region 4.
Any and all concerns raised by the FDEP for this revised document must be addressed
as required under their authority.
Sincerely,
Carl R. Froede Jr., P.O.
DOE Remedial Section
Federal Facilities Branch
Waste Management Division
cc: J. Crane, FDEP
E.Nuzie,FDEP
J. Armstrong, FDEP
219
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This Page Intentionally Left Blank
220
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PerVap™ Membrane Separation Groundwater Treatment at
Pinellas Northeast Site, Largo, Florida
221
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PerVap™ Membrane Separation Groundwater Treatment at
Pinellas Northeast Site, Largo, Florida
Site Name:
Pinellas Northeast Site
Location:
Largo, Florida
Contaminants:
Volatile Organic Compounds:
Trichloroethene (TCE)
Methlyene Chloride
1,2-Dichloroethene
Period of Operation:
6/14/95 - 3/2/96
Cleanup Type:
Demonstration
(ITRD Technology Demonstration)
Vendor:
Membrane Technology and
Research, Inc. (MTR) and the
Advanced Technology Group of
Hoechst Celanese Corp
Additional Contacts:
DOE Environmental Restoration
Program Manager:
David Ingle
(813)541-8943
Lockheed Martin Specialty
Components
Barry Rice
(813)545-6036
Technology:
Membrane Filtration:
- Membrane separation
(pervaporation) using the PerVap™
technology.
- organic permeable, hydrophobic
membrane used to remove organic
contaminants from water
- MTR PerVap pilot system was
skid-mounted; capacity of 1-2
gallons/minute on a batch basis
Cleanup Authority:
RCRA
Regulatory Point of Contact:
EPA Region 4 and State: Florida
Department of Environmental
Protection
Waste Source: Disposal of drums
of waste and construction debris
Type/Quantity of Media Treated:
Groundwater - 125 batches or 6,200 gallons
Purpose/Significance of
Application: Demonstration of the
PerVap™ technology for treating
VOC-contaminated groundwater at
the Northeast Site
Regulatory Requirements/Cleanup Goals:
- The objectives of the demonstration were to achieve greater than 99% removal of VOCs, eliminate the need for
pretreatment of groundwater, and to produce no air emissions. For effluent to the POTW, there was a discharge
limit of 850 ug/L total toxic organics.
- No air permitting or air permit modifications were required for this demonstration because the demonstration
was performed at an existing SWMU.
Results:
- Removal efficiency was highly variable (ranging from 90% when membranes were not clogged to zero when
membranes were clogged). The goal of 99% removal was not maintained during the demonstration.
- The clogging was attributed to oxidation of aqueous iron. Because of persistent clogging problems with the
membranes, groundwater pretreatment was required. Several pretreatment alternatives were tried; however, the
effectiveness and applicability of each was determined to be site-specific.
- The discharge limits were not achieved and water was treated using the existing groundwater treatment system.
- No air emissions were detected; however, a very strong odor was noted during operation.
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PerVap Membrane Separation Groundwater Treatment at
Pinellas Northeast Site, Largo, Florida (continued)
Cost:
- Total cost for pilot system - $88,728, including pre-demonstration consultation, mobilization and
demobilization, monitoring, sampling and analysis, treatment, and disposal. The total cost includes $29,000 in
costs for MTR who agreed to provide the pilot system and engineering services to Lockheed Martin on a fixed-
price basis ($5,000 for the first month and $3,000/month for eight months)
- Cost per unit of groundwater treated during the pilot test - $0.01-0.015/gallon
- Projected cost for full-scale - capital cost of $250,000 and operating cost of $0.0 I/gallon.
Description:
The Pinellas Northeast site, located at the DOE Pinellas Plant in Largo, Florida, includes the East Pond and was
identified as a Solid Waste Management Unit in a RCRA Facility Assessment conducted by EPA Region 4. The
East Pond was excavated in 1968 and used as a borrow pit. The area was used to store construction debris and
waste, including solvents, in drums and containers. In 1986 shallow groundwater at the site was determined to be
contaminated with a variety of VOCs . The predominant contaminants at the site were TCE, methylene chloride,
and 1,2-dichloroethene, detected at levels as high as 360,000 ppb, 1,200,000 ppb, and 58,000 ppb, respectively.
Vinyl chloride and toluene were also detected at relatively high concentrations.
The groundwater pump and treat system at the site includes seven recovery wells connected to an air stripper.
Effluent is discharged to a POTW. Because the aquifer is anaerobic and contains high levels of dissolved solids
and iron, the extracted groundwater must be pretreated prior to the air stripper. The purpose of the demonstration
was to determine if the pervaporation system would be able to treat the groundwater directly without pretreatment
and would be able to concentrate contaminants in a condensate that could be recycled, thereby reducing waste
disposal costs as well as air emissions.
The MTR PerVap™ pilot system was a self-contained, field transportable pervaporation system that had been
adapted for use in removing organics from aqueous liquid streams. Contaminated groundwater, pumped into a
surge tank, was passed through a cloth filter into the 50 gallon process feed tank. The pervaporation cycle, begun
when the feed tank was full, consisted of pumping a 50-gallon batch of water across a heater (to raise the
temperature to 50° C), through two membranes modules in series, then back to the feed tank. A vacuum was
applied across the membrane modules creating a pressure gradient to facilitate the transfer of VOCs across the
membranes. The resultant vapor stream or permeate (about 1,500 ml/batch) was then cooled to condense the
liquid which was then sent to a chilled permeate storage container. The treated water was discharged to a POTW.
The capacity of the pilot system was 1-2 gal/min and a typical pervaporation cycle was 1-2 hours. The residuals
produced by the system were filters and permeate, which were disposed of as hazardous waste, and used
membranes, which were returned to MTR.
Optimal operating parameters could not be established during the demonstration. Because of membrane clogging
problems caused by precipitants from the groundwater, the removal efficiencies were highly variable during the
demonstration. Several groundwater pretreatment methods were evaluated an attempt to alleviate the clogging,
including nitrogen blanketing, adding a chelator, adding a dispersant, and changing the pH of the water. The use
of a nitrogen blanketing and the dispersant produced the best results, but were not compatible with the existing
groundwater treatment system. Therefore, while cost effective pretreatment was available, the applicability is
subject to site- specific constraints. In addition, the POTW discharge limit was not achieved and the water was
treated using the existing groundwater treatment system.
223
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•• 1. SUMMARY
From July 1995 through March 1996, the Innovative Treatment Remediation Demonstration (ITRD)
Program conducted a pilot demonstration of a membrane separation (also known as pervaporation)
technology for the treatment of volatile organic compound (VOC)-contaminated ground water at the U.S.
Department of Energy's (DOE) Pinellas Plant in Largo, Florida. This technology has often been used for
separation of organic contaminants from air and industrial process water streams. These systems have
been proposed for the treatment of VOC contaminated groundwater. The pilot system used during this
demonstration was developed by Membrane Technology Research, Inc. of Menlo Park, California. The
purpose of this evaluation report is to document the demonstration activities, present demonstration data,
and provide evaluation results on the cost and performance of the MTR pilot-scale pervaporation system.
The system was evaluated for analytical and operational performance relative to defined performance
goals needed for full-scale implementation of this technology at the Pinellas Plant.
The membrane separation or pervaporation process uses an organic permeable but hydrophobic
membrane to remove organic contaminants from the water to be treated. Bench-scale testing has
suggested that removal efficiencies of 99% could be obtained. If the system could operate without
fouling the membrane from the high iron and dissolved solids in the ground water at this site, the system
would significantly reduce water pretreatment costs over the proposed baseline air stripper. Additionally,
because the separated organics are condensed and concentrated in the process, they can be recycled,
significantly reducing air emissions and waste disposal over the baseline air stripper.
The demonstration provided adequate analytical and operations data with which to evaluate the
performance of the MTR PerVap™ Pilot System. Initial operational tests indicated that organic
contaminant (TCE, DCE, and methylene chloride) removal efficiencies of 90-99% could be
accomplished with the membrane system. Batch mode operation allowed groundwater at contamination
levels as high as 1000 ppm to be reduced to 2-3 ppm in as little as 1-2 hours of treatment. The major
problems associated with continuous batch operation of the system was fouling of the membranes by
precipitated iron. Attempts to reduce this fouling through the modification of system operation and
chemical additives met with some success. During continuous batch operation, contaminants generally
could not be reduced below the 4-5 ppm total contaminant concentration. Concentration of the
contaminants in an organic condensate was demonstrated. A limited analysis of field operational costs
for the PerVap™ system shows that use of the system may provide cost-effective ground water treatment
and direct operating costs of $.01/gal for treated ground water can be obtained.
Application of the system to ground water treatment seems feasible as long as compatibility with the
chemistry of the ground water to be treated is fully considered before application. Because of the high
levels of iron and dissolved solids in the ground water, this system was unable to meet the performance
goals required for full-scale implementation at the Pinellas Plant.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
224
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2. SITE INFORMATION
Identifying Information
Facility.
OUS/WMU:
Location:
Regulatory Driver:
Type of Action:
Technology:
Period of operation:
Quantity of groundwater treated:
Site Background
DOE Pinellas Plant
Northeast Site
Largo, Pinellas County, Florida
RCRA
ITRD Technology Demonstration
Groundwater pump-and-treat with membrane separation
June 14, 1995 - March 12,1996
125 batches or 6,200 gallons
The DOE Pinellas Plant occupies
approximately 100 acres in Pinellas
County, Florida, which is situated along
the west central coastline of Florida
(Figure 1). The plant site is centrally
located within the county; it is bordered on
the north by a light industrial area, to the
south and east by arterial roads, and to
the west by railroad tracks. The
topographic elevation of the Pineilas Plant
site varies only slightly, ranging from 16
feet MSL in the southeast corner to 20
feet MSL in the western portion of the
site. Pinellas County has a subtropical
climate with abundant rainfall, particularly
during the summer months.
The Northeast Site includes the East
Pond and is located in the northeast
portion of the Pinellas Plant site
(Figure 2). The Northeast Site is covered
with introduced landscaping grass and
contains no permanent buildings. The
site contains approximately six acres and
is generally flat, with slight elevation
changes near the pond. Access to the
Northeast Site is restricted and protected
by fencing.
^1 Site History
PINELLAS
PLANT
Gulf of
Mexico
Tampa Bay
I 5-ffi: 1
Figure 1. Pinellas Plant Location.
The DOE Pinellas Plant operated from 1956 to 1994 manufacturing neutron generators and other
electronic and mechanical components fro nuclear weapons (SIC Code 9631 A-Department of Energy
Activities).
The Northeast Site is associated with the location of a former waste solvent staging and storage area.
From the late 1950s to the late 1960s, before construction of the East Pond, an existing swampy area at
the site was used to dispose of drums of waste and construction debris. The East Pond was excavated
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
225
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NEMW-3O
NfUW-lg
NEUW-23
NEUW-1S
NEMW-18
MEUW-3S
8
NEPZ-1
HEP7-3
O
NEMW-«
nnw e PINIS-OOU/
PKW-6 QSRW-3.
u nsnw-4
nnruw-17
NEUW-SA
Figure 2. Pinellas Plant Northeast Site.
in 1968 as a borrow pit. In 1986, an expansion of the East Pond was initiated to create additional
stormwater retention capacity. Excavation activities ceased when contamination was detected directly
west of the East Pond.
The Northeast Site was identified as a Solid Waste Management Unit (SWMU) in a RCRA Facility
Assessment (RFA)1 conducted by the EPA Region IV. Subsequently, a RCRA Facility Investigation
(RFI)2 was completed and approved in compliance with the facility's Hazardous and Solid Waste
Amendments of 1984 (HSWA) Permit.3
An Interim Corrective Measures (ICM) Study4 was developed and submitted to EPA for approval. EPA
issued final approval of the ICMS in October 1991, and an interim groundwater recovery system for the
Northeast Site was installed and commenced operation in January 1992. The ICM system now consists
of seven groundwater recovery wells equipped with pneumatic recovery pumps that transfer ground
water for temporary storage in a holding tank prior to being pumped to a groundwater treatment system.
Final disposition of the treated ground water is disposal in the Publicly Owned Treatment Works
(POTW). The POTW discharge limit is 850 micrograms per liter (ug/l) total toxic organics (TTO).5
Hi Release Characteristics
The Pinellas Northeast Site consists of a shallow groundwater aquifer contaminated with a variety of
VOCs, including chlorinated solvents such as trichloroethene, methylene chloride, dichloroethene, and
vinyl chloride. Because the site was used in the 1950s and 1960s for staging and burial of construction
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
226
-------
debris and drums, some of which contained solvents, contamination at the Northeast Site is believe to be
the result of leakage of solvents or resins from these drums. A recent debris removal activity at the site
confirmed the presence of multiple buried drums, many of which were empty, but had solvent residue.
The ongoing ICM system (pump and treat with air stripping) continues to recover contaminants from the
site and has been successful in preventing offsite migration of VOCs.
•I Site Contacts
Site management is provided by the DOE Pinellas Area Office (DOE/PAO). The DOE/PAO
Environmental Restoration Program Manager is David Ingle [(813)-541-8943]. The Managing and
Operating contractor for the Pinellas Plant is Lockheed Martin Specialty Components, Inc. (LMSC). The
LMSC technical contact for the Pinellas Plant pervaporation pilot study is Barry Rice [(813)-545-6036].
South North
Cross Section along Longitude 82'45'
Lot. 2T451
28W
- -100'
--SO1
- -0' Mean Sea Level
- - 5001
•I 3. MATRIX AND
CONTAMINANT DESCRIPTION
The primary environmental contamination
pathway at the Northeast Site is ground
water. The CMS6 at the site determined
that the soil was not a credible exposure
pathway. The type of matrix processed
by the remediation system during this
application was groundwater (ex situ).
^1 Site Geology/Hydrology
Based on analysis of soil borings, details
of well construction, and environmental
studies at the Pinellas Plant, the
thickness of the surficial deposit below
the site ranges from 25 to 35 feet and is
primarily composed of silty sand. The top
of the Hawthorn Group (composed
primarily of clay) at the Pinellas Plant is
encountered at depths approximately 30
feet or greater below ground surface.
The thickness of the Hawthorn Group
ranges from 60 to 70 feet. The water
table at the Pinellas Plant is generally 3 to
4 feet below the ground surface. Figure 3
shows the primary geologic units at the
site.
The groundwater system at the Pinellas
Plant is composed of three primary units:
(1) an upper unit, the surficial
aquifer, (2) an intermediate confining unit,
the undifferentiated portion of the
Hawthorn Group, and (3) a lower unit, the
Floridan aquifer. Undifferentiated
sediments lie below the surficial aquifer
and above the Floridan aquifer in Pinellas Figure 3. Geologic Section at the Pinellas Plant,
County. Because of the low permeability
of these sediments in this region, these upper sediments are not considered part of the intermediate
aquifer system and are generally considered to be a confining unit in the area of the Pinellas Plant.
Lower
Floridan
Aquifer
Base of ^mf_
Floridan Aquifer + 4- "*
,_!-., -J -.,-, L.,
,..[..,. .1. .,-!..
t *
— 1
!=
^
f+ 1 . iMe
LEGEND
Surficial Deposits
UmflfferenlWed
Hawthorn Group
Tempo Member,
ArcorfO formation.
Hawthorn CfOup
- -1000'
Inlergronular Eva porites
(Cedar Keys Formation)
Sunonnes Limestone
Qcoto Limestone
Avon Pork ilmestone
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
227
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•I Nature and Extent of Contamination
The primary contaminant group that this technology was designed to treat in this application was
halogenated volatile organic compounds. Contamination at the Northeast Site is limited to groundwater
in the surficial aquifer. Contaminants of concern detected in Northeast Site groundwater include 1,1-
dichloroethane, 1,1-dichloroethene, benzene, ethylbenzene, 1,2-dichloroethene (cis and trans isomers),
methylene chloride, toluene, trichloroethene, tetrachloroethene, methyl tert-butyl ether, vinyl chloride,
total xylenes, and chloromethane. The predominant contaminants detected at the site during
performance of the demonstration were methylene chloride, 1,2-dichloroethene, and trichloroethene.
Other VOCs which are detected in relatively high concentrations are toluene and vinyl chloride.
At various times, limited VOC contamination has been detected at most of the surficial aquifer
monitoring wells within the fenced portion of the site. However, the bulk of the contaminant mass is
located in the central portion of the site, especially in the vicinity of recovery wells SRW-3 and DRW-6
which were used to provide water for the pilot study. Table 1 summarizes the concentrations of
Important parameters detected in these two wells.
Table 1. Typical Pervaporation Influent Contaminants
(concentrations in ug/l)
Analyte
Total 1 ,2-Dichloroethene
Trichloroethene
Methylene Chloride
Vinyl Chloride
Toluene
Iron
Manganese
SRW-3
26,000
13,000
82,000
9,700
16,000
20,800
52.2
DRW-6
58,000
360,000
1,200,000
5,000
140,000
19,300
101
•I Matrix Characteristics Affecting Treatment Cost or Performance
The site includes seven operating ground water recovery wells that are connected to an air stripper for
water treatment before discharge to a public owned treatment works (POTW). The ground water at this
site has naturally high dissolved solids and high iron content. Because the aquifer is anaerobic, the
pumped ground water at this site requires pretreatment before air treatment in the air stripper. The
potential benefit of the pervaporation system would be its ability to treat the ground water directly without
costly pretreatment and to concentrate the contaminants in a condensate that could be recycled,
reducing waste-disposal costs and significantly reducing air emissions. Surficial aquifer ground water
iron concentrations at the site during the demonstration performance period ranged from 5,000 ug/L to
50,000 ug/L
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• 4. PERVAPORATION TECHNOLOGY DESCRIPTION
The technology evaluated in this field demonstration is membrane separation of multicomponent liquid
streams or pervaporation. In the pervaporation process (Figure 4), a multicomponent liquid stream is
passed across a membrane that preferentially permeates one or more of the components. The process
can be applied to the dehydration of organic liquids, removal of dissolved organic compounds from
water, and to the separation of mixed organic compounds.
^1 Technology Description
Figure 4 shows the basic pervaporation process is shown
schematically. As the feed liquid flows across a
membrane surface, the preferentially permeated organic
components pass through the membrane as a vapor.
Transport through the membrane is induced by
maintaining a vapor pressure on the permeate side of the
membrane that is lower than the vapor pressure of the
feed liquid. The pressure difference is achieved by
vacuum pump. The permeate vapor is condensed and
then removed as a concentrated permeate fraction. The
treated liquid exits on the feed side of the membrane.
The residue, depleted of the permeating component, exits
on the feed side of the membrane.
Pervaporation is especially effective for handling aqueous
streams containing VOCs in the concentration range of
100 ppm to 50000 ppm. Membranes are available to
remove a broad range of VOCs from highly hydrophobic
(toluene and TCE) to hydrophilic (ethyl acetate and
acetone) organics. The technology has application to
industries that generate VOC-containing process or
waste water streams including chemical, petrochemical,
pharmaceutical, pulp and paper, and food processing
operations.
Purified
feed
Feed
liquid
Condenser
Condensed
permeate
liquid
Figure 4. Basic pervaporation process.
The technology also has application to the treatment of contaminated surface or ground waters, as
demonstrated in this application. As the ground water flows across the membrane surface, the
preferentially permeated organics pass through the membrane as a vapor. Transport through the
membrane is induced by maintaining a vacuum on the permeate side of the membrane. The
concentrated permeate or condensate containing the recovered organics can then be recycled. The
purified ground water can then be discharged or recycled. The overall system separation effectiveness
depends on the volatility of the organic contaminants, their relative permeabilities, and the organic
concentration of the ground water. The system can provide removal efficiencies for many common
organic contaminants of 90-99% for concentration ranges of 100-1000 ppm.
The effectiveness of the pervaporation technology for separation of organics from water is dependent on
the design of the multilayer composite membranes. The membranes consist of a tough, open,
microporous polymer layer that provides strength and an ultrathin, dense polymer coating that is
responsible for the separation properties. This selective layer is very thin, typically 0.1 to 5 urn. Some
components of a fluid in contact with the membrane surface permeate the membrane faster than others,
the difference in permeation rate depending on the relative solubility and mobility of the component in
the membrane material. This difference enables separation of the feed components. Membranes can be
made of different selective polymers to meet specific separation needs. The membranes are packaged
in spiral wound modules as shown in Figure 5. During treatment, the feed fluid enters the module and
flows between the membrane leaves. The fraction of the feed that permeates the membrane spirals
inward to a central collection pipe. The rest of the feed flows across the membrane surface and exits as
the residue. To meet the capacity and separation requirements of specific applications, membrane
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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modules may be connected in a serial or parallel arrangement. The residue flow can also be recycled
through the membrane modules until the desired level of organic removal is attained.
Moduli homing
ftidflow
Cotttctlon pip*
F«ad (low
p«rmtiti (low
•tltrpMiIng through
mimbrtnt
\\\\\
Residua How
Ptrmmtv How
Rothluo flow
Spacer
Mtmbraiw
Spacar
Figure 5. Typical spiral-wound membrane module.
Hi PerVap™ Pilot System Description
Membrane Technology and Research, Inc. (MTR) and the Advanced Technology Group of Hoechst
Celanese Corporation, who provides the membrane material, have formed an alliance to market the
PerVap™ organic/water separation technology. MTR has developed a PerVap™ Pilot system that was
used for this demonstration. The MTR PerVap™ pilot system is a self-contained, field-transportable
pervaporation system which has been adapted for use in removing organics from aqueous liquid
streams. Table 2 identifies the overall system capabilities. Figure 6 is a process flow diagram of the
pilot system. Figure 7 is a photograph of the system in use at the Pinellas Plant..
Table 2. PerVap™ Pilot System Specification
Parameter
Capacity
Operation mode
Batch size
Operation
Power requirement
Support equipment
Controller
Developer's specification
1-2 gal/min.
Batch
50 gal
Continuous batches
480 V, 60Hz. 100 amp, 3-phase
Permeate collection system
Siemens
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1
r^2
SURCE
TANK
(lOQ GAl. S.S.)
MEMBRANE t MEMBRANE 2
CLOTH FILTER
WELL WELL
ORW-6 SRW-3
TREATED
WATER
TO HOR'Hctsr sac
Holding Ten*
Figure 6. PerVap™ pilot system process flow diagram.
Figure 7. PerVap™ pilot system as used at the Pinellas Plant.
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•I Technology Advantages
Treatment of VOC contaminated wastewater is practiced for several reasons: to recover valuable organic
compounds, to minimize disposal costs of hazardous wastes, and to meet regulatory requirements. The
advantages of the technology include:
• pervaporation is a low-temperature, non-destructive technology;
• VOCs are recovered in a concentrated liquid form, allowing recycling;
• no secondary wastes or air emissions requiring disposal or permitting;
• no expendable chemicals needed, and
• modular design allows easy modification to meet treatment requirements of streams with high or low
VOC concentrations and flow rates.
HI Technology Limitations
The technology has the following limitations:
• potential membrane fouling from particulates or precipitation of dissolved solids (if the membranes
foul, organic removal efficiency and cost effectiveness are reduced significantly);
• potential need pretreat for some ground water,
• diminished removal efficiencies at low organic concentration levels,
• high cost of membrane modules, and
• high initial capital costs.
•I Treatment System Schematic and Operation
Figure 6 is a schematic of the MTR Pervap™ pilot system.
Pilot system operation was controlled by a Siemens program logic controller that operated the pumps
and solenoid-operated valves to process groundwater through the system in 50-gallon batches. The
treatment system process flow was as follows:
• Groundwater was pumped to the 100-gal stainless steel surge tank.
• The groundwater was then transferred through a filter to the 55-gal stainless steel feed tank.
• When the feed tank was full, the pervaporation cycle started.
• The pervaporation cycle involved pumping a 50-gallon batch across the heater (elevating the water
temperature to 50 degrees C) across the surface of each membrane module, and back into the feed
tank.
• The pervaporation cycle timer controlled how long this process continued (typically 1 to 2 hrs). When
the timer ended the pervaporation cycle, the treated groundwater was discharged through the effluent
line.
• During the pervaporation cycle, a vacuum pump applied a pressure gradient across the membrane
modules to assist in the transfer of VOCs across the membranes. The resultant vapor stream, called
permeate, was then cooled to a concentrated liquid through a series of condensers and discharged to
a chilled permeate storage container.
• All pilot system vents were routed through an MTR vapor separation membrane that functioned
similar to the pervaporation modules by removing any VOC vapors from the air and releasing only
treated air to the atmosphere.
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Health and Safety requirements for the pilot system were limited to safety glasses during routine
operations. The tanks emitted an objectional odor during pilot system operations; however, monitoring of
the breathing zone around the pilot system with a photoionization detector did not detect any VOCs.
In continuous operating mode, system operation was automated. In this mode, personnel attendance
was not required, though system operation was checked daily.
Hi Key Design Criteria
• The MTR Pervap™ Pilot System was supplied as a complete skid-mounted system. It required only
an electrical source, a groundwater supply, and a permeate collection container to become
operational. As supplied, it was capable of treating the equivalent of 1 gal/min of ground water in a
continuous batch mode.
• The pilot system was constructed for use in a hazardous atmosphere. All metal components in the
system were corrosion resistant (mainly stainless steel) and the electrical system was contained in
explosion-proof housings. MTR chose this construction for universal application; not specifically for
the Pinellas Plant.
• The only residuals produced by the pilot system were permeate, spent filters, and used membranes.
The filters and permeate were disposed of as hazardous waste. The used membranes were returned
to MTR.
!• Operating Parameters
System throughput and temperatures are adjustable, depending on the desired effluent concentration
and contaminants being treated. For this application the following operating conditions were used:
• Average total VOC influent concentration was 1000 parts per million (ppm).
• Nominal system throughput is approximately 1 gprri (50 gal treated for 60 minutes).
• Nominal flow rate through the membrane modules was 13 to 15 gpm.
• System operating temperature used at Pinellas was 50 degrees C.
• The chiller temperature used at Pinellas was 5 degrees C.
• Permeate discharge for the Pinellas ground water was approximately 1,500 mL/batch. (30 L/day
assuming continuous 24-hr operation, relatively constant influent VOC concentration, and 1-hr
pervaporation cycle.)
• Electrical consumption was approximately 200 kWh/day.
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•I 5. REMEDIATION SYSTEM PERFORMANCE
To evaluate the performance and cost effectiveness of the pervaporation process, the MTR PerVap™
pilot-scale field system was operated at the site from July 1995 through February 1996. The following
sections of this report present the details of the technology demonstration as they relate to cost and
performance results of the PerVap™ pilot system for the treatment of VOC-contaminated ground water at
the Pinellas Northeast Site.
• Demonstration Objectives and Approach
The primary objectives of this demonstration were as follows:
1. to evaluate overall system performance in treating VOC contaminated ground water;
2. to evaluate environmental factors on system performance; and,
3. to determine expected full-scale ground water treatment costs.
The demonstration was coordinated by LMSC, the DOE site contractor for the Pinellas Plant, in
cooperation with the ITRD Program and was designed to evaluate the overall cost and performance of
the PerVap™ system. The PerVap™ Pilot System was connected to two ground water recovery wells,
each producing 1 to 2 gpm of contaminated ground water. The two wells provided ground water
contaminated with approximately 1000 ppm and 100 ppm volatile organics respectively. These wells
represented the nominal range of ground water contamination levels at the Pinellas Northeast Site. The
PerVap™ system was operated in batch mode with approximately 125 50-gal batches.
•I Performance Evaluation Criteria
Performance criteria considered in the approach for evaluating membrane separation technology
included the following:
1. removal of VOCs from groundwater without the need for pretreatment;
2. removal of VOCs to concentrations low enough to permit discharge to the POTW (a permit
requirement);
3. system operation without air emissions in excess of accepted standards; and
4. removal of ground water contaminants as a recyclable product.
The pilot system's performance was evaluated against the original anticipated pervaporation technology
benefits:
1. greater than 99% removal of contaminants from the groundwater.
2. no pretreatment of groundwater required.
3. no air emissions were observed in excess of accepted standards.
4. contaminants recovered as a recyclable product.
The approach used to operate the pilot system was based on the goal of evaluating the system for
application at the Pinellas Plant Northeast Site. The following three types of evaluations were
conducted.
• The first was an initial check of efficiency to verify performance of the membranes. This check
included verification of proper system operations, membrane performance, and determination of the
appropriate automatic operation cycle
• The second evaluation was a mechanical evaluation that focused on the actual design and
construction of the pilot system. Previous experience with treatment systems at the Pinellas Plant
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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has shown that precipitation will occur in an aerobic environment and will eventually result in fouling
or flow restriction in a treatment system. Based on this experience, the pilot system was evaluated
to determine capability of sustained performance without reduction from clogging or precipitation of
dissolved metals from the groundwater.
• The third evaluation focused on the pilot system's ability to remove VOCs during continuous (24
hrs/day) operation. MTR supplied new membrane modules for the performance evaluation.
•I Performance Summary
Before operating the pervaporation treatment system in a continuous batch mode, LMSC and MTR
performed a series of evaluations, included a filter evaluation and re-evaluation, a backwash evaluation,
and an efficiency evaluation. Filter and backwash evaluations concentrated on varying the mesh size of
the cloth filter between the surge tank and the feed/process tank. Flow pressure was measured both
before and after the cloth filter. Initially, a 1-um mesh was used. Very early in the evaluation, a pressure
differential across the filter and a reddish brown sediment were recognized in the water, fouling the filter
MTR suggested that the aeration involved in the filtration process was oxidizing the dissolved iron in the
process ground water, resulting in precipitate or increased suspended solids. Because 80% of
suspended particles in the Pinellas ground water are in the 10- to 15-um range, the 1-um mesh filter was
replaced with a 10-um mesh filter in order to improve the system flow. The initial efficiency evaluation of
process water across the membranes consisted of a 20-hour batch test with sampling every 10 min. The
greatest VOC reductions occurred in the first 60 min. Typical results are shown in Figures 8 and 9.
Subsequent performance evaluations designed to mimic full-scale operations were then conducted on a
more or less continuous batch mode. The system operated in automatic mode for 1-hour pervaporation
cycles. These evaluations included the addition of a hydrocyclone filter in front of the 10-um cloth filter,
and a cartridge filter was inserted between the heater and the first membrane. Initial VOC removal
efficiency was very good, but it decreased with time. :
A significant degree of membrane clogging occurred, likely the result of the oxidation of aqueous iron.
The system shut down after 13 batches because of pressure buildup. The premembrane filter was
replaced with coarser (20 to 100 urn) filters and the system was restarted. Over pressure shutdowns
occurred again after 56 batches, then after 2 batches. Various acid washes and backflushes failed to
solve the problems. The system was then operated with just the premembrane filter, but it rapidly shut
down again because of pressure buildup.
Removal efficiencies during this phase were initially at a 90%+ level until the filters and membranes
became clogged. Efficiency decreased to nearly zero as clogging of the membranes reduced the flow
rate to as low as 5 gpm. During the tests, aqueous iron concentrations were measured. As much as 3 to
18 mg/L of iron were being removed from the ground water during each batch treatment. It became
obvious that the system operation was oxidizing the iron in the ground water and causing the membranes
to foul. ;
Several ground water pretreatment alternatives were identified and evaluated to eliminate the iron
fouling problem. These included:
• replacing the air in the headspace of the surge and process tanks with nitrogen, thereby decreasing
the oxidation of the water while it is in the tanks;
• adding muriatic acid to lower the pH of the process ground water to 3.5 to reduce precipitation;
« adding tetrapotassium pyrophosphate as a precipitate inhibitor;
• adding citric acid as a chelator to keep the iron in solution; and
• adding Nalco 8356-D as a dispersant to prevent precipitate deposition.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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1000
* 100 -
Pervaporation Efficiency Evaluation
Batch *1 02/01/90
80 70
Tim* (min.)
100 110 120 130
Figure 8. VOC Removal Batch #1.
1000
100 -
Pervaporation Efficiency Evaluation
Batch *2 02/01/96
30 40 50 80 70 80 90 100 110 120 130
Figure 9. VOC Removal Batch #2.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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Several batch operations were conducted to evaluate the alternatives, attempting to maintain high VOC
removal rates but reduce the amount of iron being removed. In preliminary tests, nitrogen blanketing
resulted in 83% removal of VOCs and 50% less removal of iron. Blanketing plus pH adjustment yielded
similar results, but significant quantities of acid were required because of the buffering capacity of the
Pinellas ground water. With precipitation inhibition, the results were 78% VOC removal and 88% less
iron precipitation.
Efficiency evaluation testing using nitrogen blanketing and Nalco dispersant had the best results, with
over 90% VOC removal and over 90% less iron precipitation. Unfortunately, the application of this
dispersant and chelator at Pinellas was not compatible with existing ground water treatment systems at
the plant. Therefore, it was decided to use nitrogen blanketing to see how well fouling could be reduced
in continuous operations.
A mechanical evaluation was conducted to evaluate system performance for fouling/plugging of filters
and membranes during continual, 24-hr/day operation, using nitrogen blanketing of the surge and feed
tanks, 10-um filters between the tanks and before the first membrane, 70 degree C operating
temperature, and a 2-hr pervaporation cycle time. After operating continously for 6.5 days and
processing a total of 60 batches, the system continued to have filter fouling problems and showed less
efficient overall VOC removal. '.
!
Table 3 summarizes design and operational performance data resulting from continuous system
operation. The results show that pervaporation can remove VOCs from ground water at high efficiencies
andconcentrate the contaminants in a permeate. However, the membranes are susceptible to fouling in
certain geochemical conditions. Cost effective methods exist to reduce the fouling problems, but their
applicability is subject to site specific requirements and constraints. The chemistry of the ground water
to be treated must be fully evaluated before application of this technology can be considered at a site.
Table 3. Pervaporation pilot system performance summary
Performance goals
Values/results
Theoretical Pilot System Benefits
• Greater than 99% removal of volatile
organic compounds (VOCs from the
ground water
• No pretreatment of ground
water
• No air emissions
Removal efficiencywas highly variable and did not maintain
> 99% efficiency.
The POTW discharge limit was never achieved. (All effluent from the
pilot system was treated by the existing ground water treatment
system.).
Pretreatment of ground water was necessary because of membrane
clogging from ground water percipitants.
No detectable air emissions occurred, although a very strong odor
prevailed during operations.
Optimal operating parameters could not be established because of the
highly variable removal efficiencies.
Compliance levels
• Publicly Owned Treatment
Works (POTW) discharge limit
850 ug/L total toxic organics
(TTO)
Influent concentrations ranged from approximately 500 to 1,000 mg/L
total VOCs.
Effluent concentrations ranged from approximately 1 to 750 mg/L.
During optimal conditions, the effluent concentrations were
approximately 1 to 10mg/L. (Refer to Figs. 8 and 9 for typical VOC
removal data.). ;
Quantity of ground water treated
Approximately 125 batches or 6,250 gal.
Residuals
Spent filters, clogged membranes, VOC permeate.
Quantity of material disposed
« Two 55-gal drums of spent filters, two 55-aaI drums of oermeate
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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•I 6. REMEDIATION SYSTEM COSTS
The pilot system supplied by MTR for evaluation at the Pinellas Plant was subcontracted by LMSC on a
monthly fixed price basis. Under this subcontract, MTR agreed to supply the pilot system and
engineering services at the following rates:
Cost for first month:
Monthly cost thereafter:
Total cost:
$ 5,000
$ 3,000/month for 8 months
$29,000
MTR provided the following engineering services, (1) during the first month, an engineer at the site to
provide start-up assistance and training on the pilot system for 5 days, and (2) during the rest of the
evaluation period, an engineer at the site 2 days per month to monitor the equipment and provide
technical support.
The costs for the demonstration of the PerVap™ pilot system are shown in Table 4. The costs provided
are based on accepted Federal Remediation Technologies Roundtable cost elements.
Table 4. Pinellas pervaporation system cost by interagency work breakdown structure
Cost element
(with Interagency
WBS Level 2 code)
Pre-demo consultation
Mobilization and preparatory
work (33 01)
Monitoring, sampling, testing,
and analysis (33 02)a
Physical treatment (33 13)
Disposal (other than
commercial) (33 18)
Demobilization (33 21)
Total cost
Description
MTR visit & system inspection
Shipping to Pinellas
Site preparation (utilities, materials,
etc.)
System installation and startup
Sampling and analysis
Daily operations (50 days)
Membranes
Subcontract costs
Spent filters
Return shipment
Costs
($)
1,500
1,500
12,260
8,718
30,000
3,250
unknown
29,000
1,000
1,500
Subtotals
($)
1,500
22,478
30,000
32,250
1,000
1,500
88,728
'Monitoring and sample analysis costs for this evaluation were very extensive. This cost is highly variable and
depend on the number and frequency of contaminants analyzed.
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The most important cost information in this evaluation are the expected capital and operating costs for a
full-scale implementation. These costs will vary depending on the desired treatment volume and level.
MTR submitted the cost of a full-scale as part of the pilot system evaluation. The specifications for this
system are as follows: •
• design feed flow: 20 gpm
• design organics concentration in: 400 ppm total VOCs of which 250 ppm is methylene chloride
• design organics concentration out: <850 ug/L TTO, and
• capital costs: $250,000 ±20%, operating costs: $.01/gal.
The maximum site discharge to the POTW is 850 ug/L TTO. This price does not include a 2,000 gal
surge tank, a 1,000-gal feed tank, local site setup, or utility connection costs; they would be supplied
locally. '
During the evaluation of the pilot system the unit operating costs for the ground water treated varied
between $.01-$.015/gal during continuous operations. These values suggest that during full scale
operations the projected operating costs suggested by MTR will indeed be attainable, provided fouling of
the membranes is controlled.
• 7. REGULATORY/INSTITUTIONAL ISSUES
In July 1993, the DOE, EPA, the Florida Department of Environmental Protection (FDEP), and LMSC
entered into an agreement with the ITRD Program to evaluate innovative technologies to remediate
ground water contamination at the Pinellas Plant Northeast Site effectively and expeditiously.
Because the membrane separation demonstration was performed at an existing SWMU, no additional
permitting or regulatory requirements were applicable.; Ground water monitoring reports for the
Northeast Site are submitted quarterly to FDEP and EPA Region IV. For each quarterly report submitted
during the performance period of the demonstration, a description of the membrane separation
demonstration activities was provided thus agencies were made aware of the progress of the
demonstration.
Effluent from the membrane separation demonstration was expected to meet the requirements of the
Pinellas Plant's Industrial Wastewater Discharge Permit. According to this permit, the limit for TTO is
0.850 mg/l for disposal in the Pinellas County Sewer System (PCSS). (Because it was not initially known
if the effluent from the membrane separation demonstration would exceeded this limit, the effluent was
disposed with ground water that is normally treated in the plant's ground water treatment system.
No air permitting or air permit modifications were necessary to support this demonstration. Cleanup
criteria for groundwater at the Northeast Site are the FDEP maximum contaminant levels and are listed
in Table 6.
No air permitting or air permit modifications were necessary to support this demonstration.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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8. SCHEDULE
The demonstration an devaluation of the pervaporation pilot system at the Pinedas Plant, the associated
tasks, and schedule for each task are provided below.
10
1
2
3
4
(
1
7
1
»
10
11
12
13
14
15
1t
17
1t
1t
29
TatkNarrw
Parvaporation Pilot Study
System arrival
System setup & initial operation
Initial Efficiency Evaluation
Mechanical Evaluation
Filer Evaluation
Front End Plumbing Mod.«
Filer Re-evaluation
Plumbing Modifications
Backwath Evaluation
Back End Plumbing Mod.s
Membrane Changoout
Perfofmanc* Evaluation
Auto-mode Operation
Progress Evaluation by ITRD
Pretreatment Evaluation
Auto-mode Operation
Nitrogen Blanketing addition
Aufewnode Operation
SyifHTl Shut-off & Decon.
Start
6/14/95
6/1495
6/1995
7/27/95
S/22BS
8/22/95
8/31/S5
9/1/95
9/495
10/3/95
10/16/95
10/2Q/9S
10/23/88
10/23/95
11/2/95
12/12/95
1/26/96
2/15/96
3/7/96
3/12/98
Finish
3/12/36
6/14/95
7/28/95
7/27/95
10/20/86
8/30/95
8/31/95
9/1/95
10/2/95
10/13/95
10/20/95
10/20/95
3/11/16
11/1/95
12/11/95
1/24/96
2/14/96
3/5/96
3/11/96
3/12/36
=in«!las Plant Pervaporation Pilot Study
•1996
Jim I Jul I Aua I Sep Oct I Nov I Dec I Jan I Feb I Mar I Apr May Jun
^ |^ • »
h
feas [
r
^••^v
% i
i
•ih
jii
! 1
1 1
; V ™
,
i 1
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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•I 9. OBSERVATIONS AND LESSONS LEARNED
•I Cost Observations and Lessons Learned
The major cost item for the pilot system was sampling and analysis, particularly the laboratory analytical
cost, which was reflective of (1) the need to have an accelerated analysis time (3-5 days) to stay
abreast of system efficiency, and (2) the number of analytes monitored (EPA 8240A suite). If problems
with clogging and efficiency had not occurred, it might have been possible to relax the accelerated
analysis time. In addition, less contaminants of concern would have lowered analytical costs.
A limited analysis of direct operating costs for this technology shows that the system can provide cost-
effective ground water treatment provided the chemistry of the water is compatible with the system.
•I Performance Observations and Lessons Learned
The demonstration provided adequate analytical and operations data with which to evaluate the
applicability of the MTR PerVap™ Pilot System for remediation of VOC contaminated ground water.
Initial operational tests indicated that organic removal efficiencies of 90-99% could be achieved with the
pilot system. Batch mode operation allowed 50 gal of ground water at contamination levels as high as
1,000 ppm total VOCs to be reduced to 2 to 3 ppm total VOCs in as little as two hours of treatment.
However, major problems developed during continuous batch operation of the system at the Pinellas
Northeast Site because of fouling of the membranes by precipitated iron. Attempts to reduce this fouling
through the modification of system operation and some chemical additives met with limited success at
the Northeast Site. During continuous batch operation, contaminant concentrations could generally be
reduced below 4 to 5 ppm total VOCs.
IH Summary
Base on the results of the demonstration, the MTR PerVap™ system is an innovative technology capable
of providing ex-situ treatment of VOC-contaminated ground water, assuming there is no compatibility
problems between the system and the ground water. At the Pinellas Plant, the PerVap™ system was
incompatible with the ground water and the results were a major impact on system operations and
performance. Because of these impacts, the PerVap™ system failed to meet the theoretical benefits
and objectives of the technology demonstration for the Pinellas Plant.
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•I 10. REFERENCES
1. Installation Assessment, Pinellas Plant, U. S. Department of Energy, Comprehensive Environmental
Assessment and Response Program, Albuquerque Operations Office, Albuquerque, N.M., 1987.
2. RCRA Facility Investigation Report, Pinellas Plant, Vol. 1-Text, U.S. Department of Energy,
Environmental Restoration Program, Albuquerque Operations Office, Albuquerque, N. M., 1991.
3. RCRA Hazardous and Solid Waste Amendments Permit, U. S. Department of Energy Pinellas Plant,
Largo, Florida, EPA ID No. FL6-890-090-008, U. S. Environmental Protection Agency, February 9,
1990.
4. Interim Corrective Measures Study, Northeast Site, TPA2 6350.80.01, prepared by CH2M Hill for the
U. S. Department of Energy and General Electric Company, Neutron Devices Department, Largo,
Florida, May 1991.
5. Industrial Wastewater Discharge Permit, U. S. Department of Energy Pinellas Plant, Pinellas County
Sewer System, Pinellas County, Florida, 1994.
6. Corrective Measures Study Report, Northeast Site, Pinellas Plant, Largo, Florida, U. S. Department
of Energy, Environmental Restoration Program, Albuquerque Field Office, Albuquerque, N. M. 1993.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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7. 11. VALIDATION
This analysis accurately reflects the performance and costs of the remediation."
David S. Ingle, Pinellas flrea Office
U.S. Department of Energy
Mike Hightower, Technical Coordinator
Innovative treatment Remediation Demonstration Program
Sandia National Laboratories
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
243'
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Department of
Environmental Protection
Lawton Chiles
Governor
Twin Towers Building
2600 Blair Stone Road
Tallahassee, Rorida 32399-2400
June 2, 1997
Virginia B. Wetherell
Secretary
Mr. David S. Ingle
Albuquerque Operations Office
Pinellass Area Office
Post Office Box 2900
Largo, Florida 34649
Dear Mr. Ingle:
Jim Crane, John Armstrong and I have reviewed the "Cost and Performance Report,
Innovative Treatment Remediation Demonstration, PerVap Membrane Separation Ground Water
Treatment, Pinellas Plant Northeast Site" final draft dated April 15, 1997. We concur with the
purpose of the report. Unless the EPA or other parties desire modifications, we recommend that
the report proceed to "final" designation.
If I can be of any further assistance with this matter, please do not hesitate to contact me
at 904/921-9999.
Sincerely,
Eric S. Nuzie
Federal Facilities Coordinator
ESN/sr
cc: Jim Crane, FDEP Technical Review Section
John Armstrong, FDEP Technical Review Section
Bill Kutash, FDEP Southwest District
Carl Froede, US EPA Region 4
"Protect, Conserve and Manage Florida's Environment and Natural Resources"
Printed on recycled paper.
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
244
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4WD-FFB
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA FEDERAL CENTER
100 ALABAMA STREET, S.W.
ATLANTA, GEORGIA 30303-3104
CS7J6J89&
CERTIFIED MAIL ;
RETURN RECEIPT REQUESTED
The United States Department of Energy
Pinellas Plant
Attn: Mr. David Ingle
P.O. Box 2900
Largo, FL 34649
SUBJ: Cost and Performance Reports for the:
1) Dual Auger Rotary Steam Stripping Technology, and
2) Pervap Membrane Separation Technology
Demonstrations at the -Northeast Site
DOE Pinellas Plant, FL"
EPA I.D. Number FL6 890 090 008
Dear Mr. Ingle:
The Environmental Protection Agency (EPA) , Region 4, has
completed our review of the above referenced documents . Both of these
reports appear to accurately convey information gathered by the
Innovative Treatment Remediation Demonstration (ITRD) Team for the two
different technologies that were demonstrated on the small scale at
the Northeast site.
The activities associated with the Northeast Site under the
direction of the ITRD have been very important to the Agency because
the successful demonstration of the various technologies would
ultimately lead to a remedy selection for this solid waste management
unit. Additionally, the information gained from these activities is
valuable in determining the cost/benefit of using these innovative
technologies at other sites. EPA remains committed to working with
the Department of Energy (DOE) at the former Pinellas Plant to
document the success of these technology demonstrations, for a final
remedy selection at this site, and eventually facility restoration.
If you have any questions regarding the ITRD at the Northeast
Site then please contact me at (404) 562-8550.
Sincerely,
Carl R . Froede «Tr . , P . G .
DOE Remedial Section
Federal Facilities Branch
Waste Management Division
cc: Eric Nuzie, FDEP
Jim Crane, FDEP
RecyclAd/Racyclabla •Printed with Vegetable Oil Based Inks on 100% Recycled Paper (40% Postconsumer)
Cost and Performance Report - PerVap™ Membrane Separation, Pinellas Plant
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246
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Pump and Treat, In Situ Bioremediation, and In Situ
Air Sparging of Contaminated Groundwater at Site A,
Long Island, New York
247
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Pump and Treat, In Situ Bioremediation, and In Situ
Air Sparging of Contaminated Groundwater at Site A,
Long Island, New York
Site Name:
Site A (actual name confidential)
Location:
Long Island, New York
Contaminants:
Volatiles - nonhalogenated (BTEX)
- Maximum initial concentrations
were benzene (430 ug/L), toluene
(350,000 ug/L), ethylbenzene
(5,600 ug/L), and xylenes (45,000
ug/L)
Period of Operation:
Status: Ongoing
Report covers: 7/95 - 10/96
Cleanup Type:
Full-scale cleanup (interim results)
Vendor:
Treatment System Vendor:
RETEC Associates
Site Management:
RETEC Associates (1993-1997)
Land Tech Remedial, Inc. (1997-
present)
State Point of Contact:
Carl Hoffman
New York State DEC
Bureau of Hazardous Site Control
50 Wolf Road
Albany, NY 13323-7010
Site Contact:
Stephen Hoelsher
Phillips Petroleum
13 DI Phillips Bldg
Bartlesville, OK 74004
(918)661-3769
Technology:
Pump and Treat; In Situ
Bioremediation; Air Sparging, Soil
Vapor Extraction
- Groundwater was extracted using
5 wells, located on site, at an
average total pumping rate of 18
gpm
- Extracted groundwater was
treated with air stripping and
gravity separation
- Nutrients were added to the
treated water to adjust nitrogen and
phosphorus levels, and then the
water is reinjected into the aquifer
through a reinjection trench located
upgradient of the plume
- Air was injected through 44
sparging wells at points
approximately 10 ft below the
water table, in a pulsed system
operation, and effluent vapors are
collected with 20 SVE wells (16
vertical and 4 horizontal)
Cleanup Authority:
CERCLA Remedial
-RODDate: 6/24/91
EPA Point of Contact:
Maria Jon, RPM
U.S. EPA Region 2
290 Broadway, 19th Floor
New York, NY 10007-1866
(212) 637-3967
Waste Source:
Leaking drums and spills of
petroleum and solvent materials
Purpose/Significance of
Application:
Relatively high unit cost; system
included groundwater extraction,
air sparging, and SVE wells.
Type/Quantity of Media Treated:
Groundwater
- 8.4 million gallons treated as of October 1996
- LNAPL observed in several monitoring wells on site
- Groundwater is found at 15-18 ft bgs
- Extraction wells are located in 1 aquifer, which is influenced by a nearby
surface water
- Hydraulic conductivity reported as 53.5 ft/day
248
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Pump and Treat, In Situ Bioremediation, and In Situ
Air Sparging of Contaminated Groundwater at Site A,
Long Island, New York (continued)
Regulatory Requirements/Cleanup Goals:
- Remediate the groundwater to meet maximum contaminant levels (MCLs) established by the NYSDEC, which
are the primary drinking water standards.
- Cleanup goals were established for benzene (0.0007 mg/L), toluene (0.005 mg/L), ethylbenzene (0.005 mg/L),
and xylene (0.005 mg/L). !
- A primary goal of the extraction system is to contain the contaminant plume and prevent it from discharging to
the harbor; the goal is for both horizontal and vertical containment.
- A primary performance goal for in situ bioremediation is to maintain specified levels for pH, nitrogen,
phosphorus, and DO.
Results:
- Maximum BTEX levels have declined from 153 to 27 mg/L; however, cleanup goals have not been met.
Monitoring data from 1997 indicate that elevated BTEX levels persist in wells along the western portion of the
site.
- Plume containment appears to have been achieved, and performance standards were generally met for nitrogen,
phosphorus, and DO; there were several exceptions where nitrogen, phosphorus, and DO were outside the
specified ranges.
- From July 1995 to July 1996, the system removed approximately 5,314 pounds of BTEX from the groundwater
(air sparging removed approximately 85% of the BTEX and P&T the remaining 15%).
Cost:
- Actual costs for the treatment system were approximately $1,941,560 ($1,503,133 in capital and $358,427 in
O&M), which correspond to $200 per 1,000 gallons of groundwater extracted and $365 per pound of
contaminant removed.
Description:
Site A operated as a petroleum bulking facility from 1939 until 1980, and it operated as a petroleum bulking and
chemical mixing facility from 1980 to 1984. In 1984, in response to a toluene spill, EPA and the NYSDEC
investigated the site, and discovered contamination by organics and metals in the soil, and organics in the
groundwater, surface water, and air. The site was placed on the NPL in June 1986 and a ROD was signed in
June 1991.
The groundwater extraction system consists of five wells installed in the areas of highest contamination within
the plume, all screened at depths of approximately 10 ft below the water table. One well was placed in an area
where free-phase BTEX product was observed in the western portion of the site. Extracted groundwater is
treated with air stripping. After stripping, water is treated through pH adjustment and addition of nutrients, and
then re-injected into the aquifer. In addition, oxygen is injected into the aquifer through 44 ah- sparging points.
Effluent vapors from the sparging points are collected by 20 SVE wells.
j
i
Groundwater cleanup goals for this site have not been met after two years and three months of operation.
However, the remedy has contained the plume, reduced average BTEX concentrations, and recovered free-phase
product.
249
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Site A
SITE INFORMATION
Site A, Recycling Facility
Long Island, New York
(Site name is confidential)
CERCLIS*: Confidential
ROD Date: June 24,1991
Treatment Application:
Type of Action: Remedial
Period of operation: 07/95 - Ongoing
(Mass removal data collected through October
1996)
(Monitoring data collected through October
1997)
Quantity of material treated during
application: 10,130,200 gallons through
October 1997
Background
Historical Activity that Generated
Contamination at the Site: Petroleum bulk
storage, chemical bulk storage, chemical
mixing, and chemical waste storage
Corresponding SIC Codes: 4226 (petroleum
and chemical bulk stations) and 5169
(chemicals and allied products)
Waste Management Practice That
Contributed to Contamination: Leaking
drums and spills of petroleum and solvent
materials
Location: Long Island, NY
Facility Operations: [1,5,7]
• Site A operated as a petroleum bulking
facility from 1939 until 1980, and it operated
as a petroleum bulking and chemical mixing
facility from 1980 to 1984. In 1984,
operations ceased when the tenant was
evicted by the landlord. The site is adjacent
to a harbor.
• In 1984, in response to a toluene spill, the
EPA and the New York State Department of
Environmental Conservation (NYSDEC)
investigated the site. They discovered
organics and metals in the soil and organics
contamination in the groundwater, surface
water, and air. An unknown volume of
petroleum products, solvents, and other
hazardous waste was released to the soil,
groundwater, and surface water via spills
and leaks.
• The current site owner was required to
remove 255 of 410 on-site drums containing
hazardous waste. In 1986, the state
removed an additional 700,000 gallons of
hazardous waste-containing sludges and
drums, including sludge containing
polychlorinated biphenyl (PCB) from a tank.
• In June 1986, the site was placed on the
National Priorities List (NPL).
• Remedial investigations were performed
from 1987 until 1992. Visibly contaminated
soils and drums were removed. The
investigation found benzene, toluene,
ethylbenzene, and xylenes (BTEX). Other
contaminants were detected but at
concentrations below action levels. The
remaining BTEX contamination in the soil
and groundwater was left to be addressed
through full-scale remediation. Community
meetings were held during this time to hear
public concern.
• During remedial construction activities in
1995, underground storage tanks were
discovered. The tanks contained more
sources of BTEX. The tanks were removed,
and the contaminant plume was redefined to
include this additional area.
Regulatory Context:
• On June 24, 1991, the Record of Decision
(ROD) for the site was signed.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
250
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Site A
SITE INFORMATION (CONT.)
Background fCont.)
• In 1992, a Consent Decree was entered into
which named potentially responsible parties
{PRPs). The decree established that
remedial operations would be funded by the
PRPs for the first six years of operation or
until $1.75 million over and above the sums
in a PRP trustf und had been spent, at which
point the NYSDEC would assume the costs.
• Site activities are conducted under
provisions of the Comprehensive
Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments
and Reauthorization Act of 1986 (SARA),
§121, and the National Contingency Plan
(NCP), 40 CFR 300.
Site Logistics/Contacts
Remedy Selection: Extraction and treatment
of the groundwater, reinjection of nutrient-
enriched, treated groundwater to promote in situ
bioremediation, in situ air sparging, and thermal
oxidation of effluent vapors was selected for
groundwater remediation based on treatability
study results. Soil vapor extraction was
selected as the soil remediation remedy, to be
used in conjunction with the groundwater
remediation system.
Site Lead: State
Oversight: EPA
Remedial Project Manager:
Maria Jon
U.S. EPA Region 2
290 Broadway
New York, NY 10007-1866
(212) 637-3967
State Contact:
Carl Hoffman*
New York State Department of
Environmental Conservation
Bureau of Hazardous Site Control
50 Wolf Road
Albany, New York 13323-7010
Indicates primary contacts
Treatment System Vendor:
RETEC Associates
Site Management:
Land Tech Remedial, Inc. (1997-Present)
RETEC Associates, Inc. (1993-1997)
Site Contact:
Stephen Hoelsher*
Phillips Petroleum
13 Dl Phillips Bldg
Bartlesville, OK 74004
(918) 661-3769
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the
Treatment System: Groundwater and Vadose
Zone Vapors
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
251,
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Site A
MATRIX DESCRIPTION (CONT.)
Contaminant Characterization n.4.5.61
Primary Contaminant Groups: Volatile
organic contaminants
• The groundwater contaminants of concern
at the site are benzene, toluene,
ethylbenzene, and xylene (BTEX). Other
chlorinated volatile organic compounds
(CVOCs) and
semi-volatile organic compounds (SVOCs)
were detected in the groundwater, but at
concentrations below action levels.
• The maximum initial concentrations
detected in the groundwater were benzene
(0.43 mg/L), toluene (350 mg/L),
ethylbenzene (5.6 mg/L), and xyiene (45
mg/L).
RETEC, the former site engineers,
confirmed the presence of a light
nonaqueous phase liquid (LNAPL) when
BTEX product was observed in wells on site.
Figure 1 illustrates the site layout and
distribution of contaminant concentrations
detected during a 1993 sampling event. A
plume map was not available for this site.
As illustrated in Figure 1, the most elevated
BTEX groundwater contamination was
primarily detected in the central and western
portions of the site. The maximum total
BTEX concentration was 299 mg/L detected
in 1993 along the western portion of the site.
The maximum total BTEX concentration
detected in the central portion of the site
was 12 mg/L.
MlMxjaharacteristics Affecting Treatment Costs or Performance M.5.6]
Hydrogeology:
Three hydrogeologic units have been identified beneath this site.
Level A Level A is composed of sandy soil and varies in thickness from two feet to
28 feet. It is hydraulically connected to the underlying level, Level B.
Level B Level B is composed of sand and gravel, with lenses of silt and clay. It
varies from 0 to 33 feet of thickness and is hydraulically connected to the
underlying level, Level C.
Level C Level C is composed of sand and varies in thickness from 22 to 55 feet.
The groundwater at the site flows generally to the west, discharging to the harbor. The groundwater flow
is tldally influenced in the upper few feet of Level A. Underneath the three units is a clay layer at least
five feet in thickness; it is not known if this layer is continuous throughout the site.
At this time contamination has been detected only in the upper 10 feet of groundwater, in Level A. Site
engineers have concluded that BTEX contamination has been hydraulically contained in the upper 10
feet of aquifer.
The topography at the site is varied. The elevation of the southwest portion of the site is approximately
five feet above mean sea level. The northeast portion of the site, the upper site area, is a hill which
reaches a peak elevation of approximately ten feet above mean sea level. A 15-foot berm encloses the
top of the hill. Rainfall recharge to the bermed area was determined to cause local mounding of the
water table. The water table in the hill area is encountered at depths of 15 to 18 feet below ground
surface. In the southwestern portion of the site, the lower site area, the water table is encountered at
depths of approximately 8 to 10 feet below ground surface. The water table level in the lower area of the
site is tidally influenced. Water levels in the lower site area have risen and flooded soil vapor extraction
wells.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
252
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Site A
MATRIX DESCRIPTION (CONT.)
Figure 1. Site Layout and Contaminant Concentrations in the Groundwater, ug/L
(1993, Best Copy Available) [5]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
253
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Site A
MATRIX DESCRIPTION (CONT.)
Matd?Lgharacteristics Affecting Treatment Costs or Performance (ConU
Tables 1 and 2 present technical aquifer information and well data, respectively.
Table 1. Technical Aquifer Information
Unit Name
Thickness Conductivity
(ft) (ft/day)
Average Velocity
(ft/day)
Horizontal Flow
Direction
Level A 2-28 53.5 1.80 West3
Level B 0-33 53.5 1 .80 West
Level C 22-55 53.5 1.80 West
* Groundwater flow is tidally influenced in Level A but generally flows to the west and discharges into the harbor.
Source: [5,6]
TREATMENT SYSTEM DESCRIPTION
eient Technoloy
Pump and treat (P&T) with air stripping, in situ
bioremediation, in situ air sparging, and soil
vapor extraction (SVE).
and Operation F2.3.6.8T
Supplemental Treatment Technology
Nutrient addition and pH adjustment of liquid-
phase effluent prior to reinjection and thermal
oxidation of all system effluent vapor streams.
Table 2. Extraction Well Data
Well Name
GWX-0
GWX-1
GWX-2
GWX-3
GWX-4
Unit Name
Level A
Level A
Level A
Level A
Level A
Screen Depth Below
Water Table (ft)
10
10
10
10
10
Design Yield
(gal/min)
1-3
1-3
6-8
1-3
1-3
Source: [5,6]
System Description
• The groundwater extraction system consists
of five wells installed in the plume, all
screened at depths of approximately ten
feet below the water table. Table 2 presents
extraction well data. Wells were placed in
the areas of highest contamination.
Groundwater is continuously withdrawn from
the shallow aquifer, Level A, and treated
through an air stripper. From 1995 to 1996,
RETEC calculated that the system operated
at an overall average extraction rate of 18
gpm, based on the actual volume of water
treated.
Well GWX-2 was placed in an area where
free-phase BTEX product was observed in
the western portion of the site. The
extraction rate from GWX-2 was designed
to be 6-8 gpm, greater than the 1-3 gpm
design extraction rate for the other four
wells. The elevated extraction rate in well
GWX-2 promoted recovery of free-phase
BTEX as well as recovery of the more highly
contaminated part of the plume.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
254
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Site A
TREATMENT SYSTEM DESCRIPTION (CONT.)
Svstem Description and Operation (Cont.)
The treatment system consists of a feed
holding tank, a low profile air stripper,
gravity separation tanks, effluent storage
tanks, and a sand filter.
The feed holding tank regulates
groundwater flow to the air stripper from the
extraction wells. The extracted water is fed
to the air stripper at a constant rate of 18
gpm through a pipe located at the bottom of
the tank.
The air stripper is a stacked, stainless steel
tray tower, consisting of four trays stacked
77 inches high. Each tray is 44 inches wide
and 32 inches deep. Countercurrent flows of
air and water are sent through the air
stripper.
Effluent from the air stripper passes through
gravity separation/effluent storage tanks.
Metals (at levels below concern) and
paniculate matter are gravity separated and
filtered into a sludge. The sludge is pumped
out for eventual off-site disposal. The
remaining water is then treated for
reinjection.
The water is treated to promote in situ
bioremediation when reinjected. The pH of
the water is adjusted in the effluent storage
tank. Treated water is then pumped through
a sand filter, and nutrients are added to
adjust the nitrogen and phosphorous levels.
The treated water is reinjected into the
aquifer through a reinjection trench located
upgradient of the plume.
Enhanced in situ bioremediation is achieved
by adding nutrients at the reinjection point
and supplying oxygen through air sparging
points. BTEX compounds are biodegraded
to end products of carbon dioxide and water
by heterotrophic organisms (refer to later
discussion under Performance Data
Assessment, regarding heterotrophs)
Pilot tests determined that optimal
conditions for BTEX degrading organisms
include a pH between 6.0 and 8.0 and
nitrogen and phosphorus levels between 1
and 5 mg/L each. Target dissolved oxygen
levels are between 2 and 8 mg/L.
The SVE and air sparging systems are
composed of air sparging and SVE wells.
Air is injected through 44 sparging wells at
points approximately 10 feet below the
water table. The sparging system is pulsed
at a system interval time of one day on two
days off and at a period time of two hours
on and one hour off.
The effluent vapors from the sparging points
are collected by 20 SVE wells. The SVE
wells, 14 vertical and six horizontal, were
placed in the vadose zone, a few feet above
the water table. In the upper site area, the
16 vertical vapor extraction wells were
placed at an average a depth of 12 feet. In
the lower site area, the six horizontal vapor
extraction wells were placed approximately
six to eight feet deep. Horizontal wells were
used in the lower site area because the
groundwater is shallow.
The SVE wells in the lower site area
occasionally become flooded because
groundwater levels are tidally influenced.
These SVE wells are equipped with water
level detectors which automatically shut off
the wells to protect the system from taking
in water. When water levels rise, only the
affected wells are shutdown while the
remainder of the SVE system continues to
operate.
The lower area of the site is paved to seal
out atmospheric vapors from the SVE
system and to further extend the radius of
influence of the horizontal vapor extraction
lines.
The effluent vapors from the SVE system
and from the air stripping tower pass
through a thermal oxidation unit to destroy
the VOCs before discharge to the
atmosphere.
Groundwater quality is monitored quarterly
through a combination of five extraction
wells, two air sparging wells, and three
shallow monitoring wells. The air
sparging/SVE system performance is
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
255
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Site A
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation (Cont.l
monitored quarterly by analyzing soil vapor •
in 20 vapor extraction wells and five vapor
monitoring points. The vapor-phase loading
to the thermal oxidation unit and the effluent
to the thermal oxidation unit is monitored on
a monthly basis.
•
System Operation
• Quantity of groundwater pumped from the
aquifer in gallons:
Volume Pumped
Year (gal)
July 1995 - July 1996 1,550,000
August 1996-July 1997 6,730,000
August 1997 - October 1997 305,000
• Since September 1995, the P&T system has
operated approximately 75% of the time.
Problems during startup, primarily iron
clogging in the injection wells, caused the
low operation rate. Iron levels decreased
after the first month of operation, and well
clogging is no longer a problem. Currently,
the treatment system is shut down on a
weekly basis to clean the extraction wells
and backflush the sand filter.
• The in situ air sparging and SVE system has
been operational approximately 90% of the
time.
Parameters Affecting Treatment Cost or Performance
Nutrients, in the form of ammonium
chloride, monopotassium phosphate, and
dipotassium phosphate, are dissolved in
batches and added to the effluent tank
approximately every two weeks.
The original air sparging and SVE system
was expanded in September 1995 to
address the underground storage tank
contamination detected during demolition
activities. Five air sparging wells and two
SVE wells were added in the lower site
area; two additional air sparging wells were
added in July 1996. The air sparging and
SVE system described under System
Description reflects this expansion.
LNAPL was visually observed in the air
stripper influent holding tank in 1995 and
1996. Groundwater to be treated is fed
from the bottom of the tank to avoid treating
the LNAPL through the stripper. The free
product was vacuumed into a wastewater
truck for off-site disposal. The amount of
free product recovered was not monitored,
but the RETEC site contact estimated that
approximately 40 gallons of free product
were recovered in 1995 and 1996. No
product was observed in 1997.
The major operating parameters affecting cost or performance for the technologies used at this site are
listed in Table 3.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
256
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Site A
TREATMENT SYSTEM DESCRIPTION (CONT.)
Paramptpr«i Affectina Treatment Cost or Performance (Cont.)
Table 3: Performance Parameters
tj> '•" (n- *Z* i» ^Parartfejtef/ --^ -^"'' ^f
Average P&T Extraction Rate
Soil Vapor Extraction Vacuum Rate
System Sparge Rate
Performance Standards for In Situ
Bioremediation
Performance Standards for P&T Reinjection
(Primary Drinking Water Standards)
Remedial Goals
(aquifer)
. ' >, / -^v :"ValP^'r^s '' ''^ *>*'
18 gpm (design)
j 660 scfm (design)
330 scfm (design)
6.0 < pH < 8.0
1 mg/L < Nitrogen < 5 mg/L
1 mg/L < Phosphorus < 5 mg/L
2 mg/L < Dissolved Oxygen < 8 mg/L
; benzene 0.0007 mg/L
toluene 0.005 mg/L
, ethylbenzene 0.005 mg/L
xvlene 0.005 mg/L
NYSDEC Primary Drinking Water Standards
(see above)
Source: [2, 3]
Table 4 presents a timeline for this remedial project.
$" - '
Start Date
6/10/86
1987
06/91
06/92
09/92
03/94
05/94
08/94
—
09/95
7/96
*'. J=n-/ . , - *. t „ , *\ - ^
Site listed on NPL
Remedial Investigation and Feasibility Study performed
Record of Decision signed
Consent Judgment entered into
Pre-Remedial & Remedial Design Activities begin
Remedial Design Approved by New York State Department of Environmental
Conservation
Site structures decommissioned and demolished
Remedial system constructed
System begins operation and quarterly monitoring begins
Extraction system is expanded
Additional air sparging wells added
Source: [1, 2]
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
257
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Site A
TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards
The groundwater cleanup goal for this site is to
remediate the groundwater to meet the
Maximum Contaminant Levels (MCL)
established by the NYSDEC, which are the
Primary Drinking Water Standards. The
cleanup goals are listed in Table 3 and are
applied throughout the aquifer, as measured in
all on-site monitoring wells [1].
Treatment Performance Goals T1.21
The primary performance goal of the
extraction system is to contain the
contaminant plume and prevent it from
discharging to the harbor. The goal is both
horizontal and vertical containment.
The primary performance goal of the
treatment system is to reduce BTEX
concentrations to the performance
standards listed in Table 3.
Performance Data Assessment [3.4.6.81
The primary performance goal regarding in
situ bioremediation is to maintain a pH level
between 6.0 and 8.0, nitrogen and
phosphorous levels between 1 and 5 mg/L,
and dissolved oxygen levels between 2 and
8 mg/L.
The primary performance goals of the air
sparging system are to sparge at the
minimum rate needed to achieve BTEX
removal and to maintain a dissolved oxygen
level between 2 and 8 mg/L to promote in
situ bioremediation.
Total BTEX Includes benzene, toluene,
ethylbenzene, and total xylenes.
• Maximum BTEX levels have declined from
153 mg/L to 27 mg/L, a reduction of 82
percent. However, cleanup goals have not
been met at this site [3]. Monitoring data in
1997 indicate elevated BTEX levels persist
in wells along the western portion of the site.
• Figure 2 illustrates that, overall, average
BTEX levels have been reduced from 0.160
to 0.026 mg/L Average concentrations of
individual constituents were reduced to
0.0008 mg/L (benzene), 0.002 mg/L
(toluene), 0.001 mg/L (ethylbenzene), and
0.01 mg/L (xyiene). However, the October
1997 sampling event revealed maximum
benzene levels of 0.008 mg/L, maximum
toluene levels of 14.0 mg/L, maximum
ethylbenzene levels of 0.018 mg/L, and
maximum xylenes levels of 13.4 mg/L, all
above cleanup goals.
Containment of the plume appears to have
been achieved based on quarterly
groundwater monitoring results.
For the enhanced in situ bioremediation,
performance standards for nitrogen were
met from July 1995 to July 1997. During
that time, average monthly nitrogen levels
were between 2 and 5 mg/L. However, from
July 1996 to October 1996, nitrogen levels
were above the 5 mg/L performance
standard.
For the enhanced in situ bioremediation,
performance standards for phosphorous
were met from June to October 1997.
During this time, average phosphorus levels
were at 1 mg/L. However, from July 1995
through May 1996, average phosphorus
levels were below the 1 mg/L performance
standard.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
258
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Site A
TREATMENT SYSTEM PERFORMANCE (GONT.)
Performance Data Assessment (Cont.)
• For the enhanced in situ bioremediation,
performance standards for dissolved oxygen
were met from July 1995 through March
1996 and from August 1996 through
October 1997. During this time, average
dissolved oxygen levels were between 2.0
and 8.0 mg/L However, from April 1996
through July 1996, dissolved oxygen levels
were below the 2.0 mg/L performance
standard.
• Between July 1995 and July 1996,
approximately 8,845,200 gallons of
groundwater passed through the air stripper.
Based on computer model results which
accounted for location of air sparging points
and groundwater flow, RETEC
approximated that the air-sparging/SVE
system treats approximately 686,000
gallons per year. Based on those values,
the total volume of groundwater treated
through both the P&T and air sparging
systems between July 1995 to October 1996
was 9,703^500 gallons.
Figure 3 presents the removal of BTEX by
the P&T and air sparging treatment systems
from July 1995 to October 1996. From July
1995 to July 1996, the P&T system and the
air sparging system have removed
approximately 5,314 pounds of BTEX from
the groundwater. The contaminant mass
removed by the SVE system is not included
in this estimate because this report
addresses the groundwater remedy, not the
soil remedy.
• In addition to the contaminant removal
illustrated in Figure 3, the in situ
Performance Data Completeness T3.41
bioremediation is believed to provide
continuous treatment of a portion of the
plume. The mass of contamination
degraded through bioremediation is not
measured directly. However, the site
operators measure the number of
heterotrophs in the groundwater. Monitoring
data has shown that the population of
heterotrophs has been sustained.
The mass of free product recovered by the
extraction system is not included in Figure
3.
According to measurements performed by
RETEC (see next section), the air sparging
system removed approximately 85% of the
5,314 pounds of BTEX. The P&T system
removed 15% of the BTEX.
The BTEX removal rate reached a peak of
approximately 20.1 Ibs/day after six months
of operation. The cumulative removal rate
has varied between 20.1 Ib/day and
7.6 Ib/day during the life of the system.
LNAPL has not been observed in any wells
since the April 1996 sampling event. The
small BTEX plume in the area of well
GWX-2 is believed to have been recovered.
However, GWX-2 will continue to be
pumped at a higher rate compared to the
other wells to extract the more concentrated
portion of the plume.
Effluent BTEX levels are not measured prior
to reinjection.
Data are available for BTEX concentrations
in the groundwater in some wells during
quarterly sampling events from July 1995 to
October 1997. Data were obtained for the
October 1996 quarterly sampling event but
were not included in the analysis, as
explained below in Performance Data
Quality. The air stripper influent and
effluent have not been monitored for
contaminant levels. Data on vapor from
sparging and SVE are available in some
SVE wells during quarterly sampling events
from July 1995 to October 1996. Vapor
contaminant loading to the thermal
destruction unit has been measured on a
monthly basis. Quarterly monitoring data
are available in Quarterly Monitoring
Reports. Weekly monitoring data are
summarized in the monthly reports, and
actual weekly readings are available from
the site engineer.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
259
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Site A
TREATMENT SYSTEM PERFORMANCE (CONT.)
0.000
Apr-95 JuI-95 Oct-95 Feb-96 May-96 Aug-96 Dec-96 Mar-97 Jun-97 Sep-97 Jan-98
— « — Benzene
— • — Toluene
—A — Ethylbenzene —
x— Xylene —
*— Total BTEX
Figure 2. Average BTEX Concentrations (from July 1995 to July 1996)*[3,6]
*Data from October 1996 were not included - see Performance Data Quality
6,000
o
-Total Groundwater Mass Flux
- Pump and Treat Mass Flux
-Air Sparging Mass Flux (not including SVE)
- Cumulative Mass Removed (Ibs)
Figure 3. Mass Flux Rate and Cumulative Contaminant Removal (July 1995 to October 1996) [3]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
260
TIO3.W P6\0422-02.stf
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Site A
TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Completeness (Cont.l
• Total BTEX mass removal was determined
by RETEC using analytical results from
influent to and effluent from the thermal
destruction unit. RETEC calculated the
BTEX mass removed by the SVE system
and the air sparging system based on
charcoal tube data sampled on a quarterly
basis. RETEC determined the mass
removed by the P&T system as the
difference between the total BTEX removal
and the BTEX removal by the SVE system
and the air sparging system. RETEC
calculated that the mass removed by the air
sparging system alone was based on an
observed 7:3 ratio between mass removed
by SVE to mass removed by air sparging.
Performance Data Quality
The BTEX mass removed by the P&T
system did not include the free product
mass that is separated prior to treatment.
The amount of free product recovered was
not monitored.
A geometric mean was used for average
groundwater concentrations detected in five
extraction wells, two air sparging wells, and
three shallow monitoring wells located within
the original plume area. A geometric mean
was used to show the trend across the entire
plume. When concentrations below
detection limits were encountered, half of
the detection limit was used.
The sampling event performed in October
1996 did not meet QA/QC requirements in
that BTEX concentrations were detected in
both trip and field blanks. Therefore, data
from this sampling event were not included
in the analyses performed in this report [3].
The QA/QC program used throughout the
remedial action met the EPA and the State
of New York requirements. All monitoring
was performed using EPA-approved SW-
846 Methods 601, 602, 624, 625, 353.2,
365.2. The only vendor-noted exception to
the QA/QC protocols occurred during the
October 1996 sampling event described
above [3].
TREATMENT SYSTEM COST
Procurement Process
The group of responsible parties contracted with RETEC to design and construct the remediation system,
under the oversight of the NYSDEC. After six years of system operation or after $1.75 million over and
above the sums in a trust fund have been spent, the NYSDEC will take over system operation and will
assume the remaining costs. ;
Cost Analysis
The responsible parties assumed all costs for design and construction and operation of the treatment
system at this site.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
261
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Site A
TREATMENT SYSTEM COST (CONT.)
Capital Costs F6.71
Oneratina Costs F6,71
Remedial Construction
Well construction (extraction, $1,007,915
monitoring, sparge, SVE)
Treatment system (air stripper, $97,944
holding, tanks, chemical mixing
tanks)
Building $100,960
Fence/Security $17,392
Construction Management $122,579
Total Remedial Construction $1,583,133
Utilities $59,782
Operations & Maintenance $90,903
Monitoring $30,658
Consumable (Chemicals and $27,291
Nutrients)
Disposals (sludge, free product) $9,663
Project Management and Reporting $121,209
Miscellaneous $18,921
Total Operating Cost (July 1995 - $358,427
October 1996)
Other Costs T6.71
Remedial Design
Remedy $539,320
Expansion $32,586
Excavation and disposal of tanks $179,035
Demolition of buildings $57,308
EPA and NYSDEC Oversight $20,000
CV»<*t Data Qnalitv
Actual capital and operations and maintenance cost data are available from the responsible party contact
and the treatment vendor for this application. The cost of SVE wells (source control) could not be
separated from the groundwater system costs.
OBSERVATIONS AND LESSONS LEARNED
Actual costs for the P&T, in situ
bioremediation, and in situ air sparging and
soil vapor extraction treatment application
at Site A were approximately $1,941,560
($1,583,133 in capital and $358,427 in
operations and maintenance), which
corresponds to $365 per pound of
contaminants removed and $200 per 1,000
gallons of groundwater treated.
The site remediation system has been in
operation for two years and three months.
No substantial changes to the cost of the
remedial system at this site were incurred
during implementation. The system
expansion constructed in September 1995 is
included in the presented costs and had no
impact on schedule [7].
EPA
According to the site contact, the use of
skid-mounted modular equipment reduced
construction costs. Additionally, the
responsible parties have indicated the
competitive bidding process used resulted in
lower costs [7].
The groundwater cleanup goals for this site
have not been met after two years and three
months of operation. However, the selected
remedy has worked to contain the plume,
reduce average BTEX concentrations, and
to recover LNAPL.
RETEC observed the air sparging portion of
the system has accounted for 85% of BTEX
removal from the groundwater, while the
P&T system accounted for 15% of BTEX
removal in the groundwater.
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
262
TI03.WP6\0422-02.stf
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Site A
OBSERVATIONS AND LESSONS LEARNED (CONT.)
The success of the remedial systems is, in
part, due to the simple aquifer material
under the site. The uniform sandy soil at
the site allowed sufficient sparging and SVE
rates, as well as simplified zones of
influence for extraction wells.
The heterotroph population has been
maintained at the level necessary to
achieve bioremediation [8].
Nitrogen levels met the performance goals
of 1 to 5 mg/L from July 1995 through June
1996 but were above 5 mg/L from July 1996
to October 1997. The site operator
encountered levels above 5 mg/L in 1997,
and the amount of ammonium chloride
added was reduced [3].
Phosphorous levels did not meet
performance goals and were detected below
the optimal range of 1 to 5 mg/L from June
1996 to October 1996. In 1997, the
phosphorous levels increased to optimal
levels.
The performance of the treatment system
and the area of influence of the enhanced in
situ bioremediation system could not be
determined because it is not monitored.
REFERENCES
1. Record of Decision. U.S. Environmental
Protection Agency, Site B. June 24 1991.
2. Remedial Action Report. RETEC. February
1996.
3. In situ Monitoring for the Integrated
Subsurface Remediation System. RETEC.
February 1997.
4. Monthly Operations Report. RETEC.
December 1996.
5. Preremedial Design Investigation Report.
RETEC. July 1993.
6. Correspondence with Mr. Steve Mclnerny,
RETEC, April 1997 and May 1997.
7. Correspondence with Mr. Steve Hoelsher,
Phillips Petroleum, September 23,1997.
8. Correspondence with Mr. Chris Poole, Land
Tech, June and July 1998.
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
263
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r
This Page Intentionally Left Blank
264
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In Situ Permeable Reactive Barrier for Treatment of
Contaminated Groundwater at the U.S. Coast Guard Support Center,
Elizabeth City, North Carolina
265
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In Situ Permeable Reactive Barrier for Treatment of
Contaminated Groundwater at the U.S. Coast Guard Support Center,
Elizabeth City, North Carolina
Site Name:
U.S. Coast Guard Support Center
Location:
Elizabeth City, North Carolina
Contaminants:
Chlorinated solvents and heavy
metals
- Maximum concentrations
detected during initial
investigations included TCE
(>4,320 ug/L) and hexavalent
chromium (Cr* (>3,430 ug/L))
Period of Operation:
Status: Ongoing
Report covers: 7/96-7/97
Cleanup Type:
Full-scale cleanup (interim results)
Vendor:
Design: University of Waterloo
Contractor: Parsons Engineering
Science, Inc.
Licensing: Environmental
Technologies, Inc.
Installation: Horizontal
Technologies, Inc.
USCG Project Manager:
Jim Vardy, P.E.
U.S. Coast Guard
CEU Cleveland Env. Engr.
Building 19
Elizabeth City, NC 27909
(919)335-6847
U.S. EPA Contact:
Robert Puls
U.S. EPA, Robert S. Kerr
Environmental Research Center
Nat. Risk Mgmt. Research Lab.
P.O. Box 1198
Ada, OK 74821
(580)436-8543
Technology:
Permeable Reactive Barrier (PRB)
- The PRB (treatment wall) is
100% granular iron, 2 ft wide, 152
ft long, begins 4-8 ft below ground
surface (bgs) and extends to 24 ft
bgs
- The PRB consists of 450 tons of
granular zero-valent iron
Cleanup Authority:
RCRA Corrective Action - part of
an Interim Corrective Measure
State Point of Contact:
Surabhi Shah
North Carolina DENR
Hazardous Waste Section
401OberlinRd., Ste. 150
Raleigh, NC 27605
Waste Source:
Spills and leaks to the subsurface
through floor drains and holes in
building floor
Purpose/Significance of
Application:
Use of PRB to treat groundwater
contaminated with TCE and
hexavalent chromium; extensive
sampling conducted to evaluate
PRB.
Type/Quantity of Media Treated:
Groundwater
- 2.6 million gallons (estimated) treated
- DNAPL suspected in groundwater at the site
- Groundwater is found at 6 ft bgs
- The PRB is located in 1 aquifer at the site; this aquifer is influenced by a
nearby surface water
- Hydraulic conductivity ranges from 11.3 to 25.5 ft/day
266
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Permeable Reactive Barrier for Treatment of
Contaminated Groundwater at the U.S. Coast Guard Support Center,
Elizabeth City, North Carolina (continued)
Regulatory Requirements/Cleanup Goals: ,
- Cleanup goals for this site are primary drinking water standards, with the following specific cleanup goals for
the aquifer down-gradient of the wall: TCE (5 ug/L) and Cr+6 (0.1 ug/L).
- A secondary goal of the PRB is to contain the contaminated part of the plume up-gradient of the reactive zone.
Results:
- Cr*6 concentrations were below the cleanup goal in all down-gradient monitoring wells in November 1996 and
September 1997 sampling events. However, TCE concentrations were above the cleanup goal in four of the
six down-gradient wells in September 1997.
- A pilot study performed in 1994 and 1995 was successful at demonstrating the effectiveness of the PRB
technology at this site; these results lead to the selection of PRB as the remedy for this RCRA corrective
action.
- The data indicate that the TCE plume may not be contained; however, the reason for the elevated TCE
concentrations in some down-gradient wells has not been confirmed.
Cost:
- Estimated costs for PRB were $585,000 ($500,000 in capital and $85,000 in O&M), which correspond to $225
per 1,000 gallons of groundwater treated.
- According to the USCG site contact, by using a PRB, the USCG will save nearly $4,000,000 in construction
and long-term maintenance costs, when comparing PRB with a typical pump and treat system.
Description:
The Support Center, Elizabeth City (SCEC), is a USCG facility providing support, training, operation, and
maintenance associated with USCG aircraft. The facility included an electroplating shop which operated for
more than 30 years, ceasing operation in 1984. In December 1988, a release was discovered during demolition
of a former plating shop. Soil excavated beneath the floor of the former plating shop was found to contain high
levels of chromium. Subsequent investigations indicated that the groundwater had been impacted by chromium
and chlorinated solvents. Multiple sources were suspected of having contributed to the groundwater
contamination. A full-scale PRB was constructed as part of an Interim Corrective Measures (ICM) associated
with a voluntary RCRA Facility Investigation (RFI), with the electroplating shop identified in the facility's
RCRA Part B permit as a Solid Waste Management Unit (SWMU).
The PRB used at this site consists of 450 tons of granular zero-valent iron keyed into an underlying low
conductivity layer at a depth of approximately 22 ft bgs. The required residence time in the treatment zone has
been estimated as 21 hours, based on a highest concentration scenario. The average velocity through the wall
was reported as 0.2 to 0.4 ft/day. Analytical data from the firstyear of full-scale operation show that the cleanup
goal for Cr+6 has been met, but not the goal for TCE. Several possible reasons are provided for the elevated TCE
levels. ;
267
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U.S. Coast Guard Support Center
SITE INFORMATION
Identifying Information;
U.S. Coast Guard Support Center
Elizabeth City, North Carolina
CERCLIS #: Not applicable
ROD Date: Not applicable
Backaround
Treatment Application:
Type of Action: Corrective Action
Period of operation: 7/1/96 - Ongoing (Data
collected through September 1997).
Quantity of groundwater treated during
application: 2.6 million gallons (estimated)
Historical Activity that Generated
Contamination at the Site: Electroplating
Operations
Corresponding SIC Code: 3471
(Electroplating of metals)
Waste Management Practice That
Contributed to Contamination: Spills and
leaks to the subsurface through floor drains and
holes in building floor
Location: Elizabeth City, North Carolina
Facility Operations: [1,2,5]
• The Support Center, Elizabeth City (SCEC)
is a U.S. Coast Guard (USCG) facility
providing support, training, operation and
maintenance associated with USCG aircraft.
• The groundwater plume is adjacent to a
former electroplating shop which operated
for more than 30 years. Operation ceased
in 1984.
• In December 1988, a release was
discovered during demolition of the former
plating shop. Soil excavated beneath the
floor of the former plating shop was found to
contain chromium at concentrations up to
14,500 mg/kg.
• The majority of the contaminated soil at the
site was believed to have been excavated
during the 1988 activities. Subsequent
investigations indicated that the
groundwater had been impacted by
chromium.
• Additional investigations by the USCG
indicated the presence of chlorinated
compounds in the groundwater. Multiple
sources were suspected of having
contributed to the groundwater
contamination.
• A pilot study was initiated at the site in 1994
to demonstrate the effectiveness of the
permeable reactive barrier (PRB) (iron
treatment wall) at this site. Two different
types of iron were poured into 16 cm inside-
diameter hollow stem augers. A total of 21
iron cylinders were installed from 3 to 8
meters below ground surface. The cylinders
were installed in three rows. Groundwater
samples were taken downgradient of the
iron cylinders to test for reduced
groundwater concentrations.
• A full-scale PRB was installed in June 1996.
The iron wall was constructed using a
trencher which excavated the soil and back-
filled with iron in one pass. The wall was
installed in seven hours.
Regulatory Context:
• The full-scale PRB was constructed as part
of an Interim Corrective Measures (ICM)
associated with a voluntary RCRA Facility
Investigation (RFI). The electroplating shop
is identified in the facility's RCRA Part B
permit as Solid Waste Management Unit
(SWMU) No. 9. Corrective actions at the
site are regulated under 40 CFR Subpart F.
Remedy Selection:
• An in situ PRB was selected as the remedy
for this site.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
268
TIO3.WP6YI128-01 .stf
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U.S. Coast Guard Support Center
SITE INFORMATION (CONT.)
Site Logistics/Contacts
Site Lead: USCG-Lead
Oversight: State
USCG Project Manager:
Jim Vardy, P.E.*
U.S. Coast Guard
CEU Cleveland Environmental Engineer
Bldg. 19
Elizabeth City, NC 27909
919-335-6847
Remedial Project Manager:
Surabhi Shah
North Carolina Department of Environment and
Natural Resources (DENR)
Hazardous Waste Section
401 Oberlin Rd., Ste. 150
Raleigh, NC 27605
indicates Primary Contact
Treatment System Vendor:
Design
University of Waterloo, Waterloo, Canada
Contractor Support
Parsons Engineering Science, Inc. Gary, NC
Licensing
Environmental Technologies, Inc. Ontario,
Canada
Installation
Horizontal Technologies, Inc.
Additional Contact:
Robert Puls
USEPA
Robert S. Kerr Environmental Research Center
Subsurface Protection and Remediation
Division
National Risk Management Research
Laboratory
P.O. Box1198
Ada, OK 74821
580-436-8543
MATRIX DESCRIPTION
Matrix Identification
Type of Matrix Processed Through the Treatment System: Groundwater
Contaminant Characterization l"l. 51
Primary Contaminant Groups: Halogenated
volatile organic compounds (VOC) and metals
• Contaminants of concern at the site are
trichloroethene (TCE) and hexavalent
chromium (Cr*6).
• Maximum concentrations detected during
initial investigations included TCE (>4,320
Mg/L) and Cr*6 (>3,430 |jg/L).
• Figure 1 is a contour map which depicts
total chromium concentrations detected
during a July/August 1994 sampling event.
At least two overlapping plumes were
identified at the site. A plume consisting of
Cr*6 and minor amounts of halogenated
VOCs began near the north end of the
former electroplating shop and migrated
north with the general groundwater flow
direction. A second plume of primarily
halogenated VOCs emanated from unknown
sources. Most of these sources were
suspected to be associated with old sewer
drain lines. This plume also migrated north
and overlaped the first plume. The plume .
discharged to the Pasquotank River.
According to the site contact, the presence
of dense non-aqueous phase liquid
(DNAPL) at this site is likely based on
elevated concentrations detected in
groundwater samples and processes known
to have occurred in the electroplating shop.
The contaminant plume was estimated to be
up to 5-6 feet thick and cover a 34,000
square foot area. The volume of
contaminated groundwater was estimated to
be 1.3 million gallons.
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
269
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U.S. Coast Guard Support Center
MATRIX DESCRIPTION (CONT.)
F/gure ?. P/ume Map Depicting Total Chromium Concentrations (detected in July/August 1994)
Modified From [2]
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
270
TIO3.WP6Y1128-01 .Stf
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U.S. Coast Guard Support Center
MATRIX DESCRIPTION (CONT.)
Affectina Treatment Costs or Performance
Hydrogeology: [1,2]
Four distinct hydrogeological units have been identified beneath this site. Groundwater begins
approximately six feet below ground surface and a highly conductive zone is located between 16-20 feet
below ground surface. This conductive layer coincides with the highest aqueous concentrations of
chromate and chlorinated organic compounds found on site. Groundwater flows in a north direction
toward the Pasquotank River. A low conductivity layer of clayey fine sand to silty clay is located at a
depth of approximately 22 feet. This layer acts as an aquitard to the contaminants located immediately
above. This information was used when designing the treatment wall depth to end in a low conductivity
layer to prevent contaminants from flowing under the treatment zone.
Unit 1 Surficial Brown to yellow-brown sandy to silty clay. This is a non water-bearing
Sediments unit.
Unit 2 Surficial Medium to fine sand or silty to clayey sand, with interbedded sandy clays
Sediments ranging from stiff to loose and brown to tan. This is the upper water-
f bearing unit at the site.
Units Surficial Dense gray to green clay or silty clay. This unit acts as a major aquitard
Sediments between the upper aquifer and the Yorktown Formation.
Unit 4 Yorktown Fine to medium clayey and silty sand. This unit is a major water-bearing
Formation formation. Groundwater in this unit has not been impacted by site
contamination.
i
Tables 1 and 2 present technical aquifer information and well data, respectively.
Unit
1
2
3
4
Thickness
(ft)
6-8
50-60
25
>100
Conductivity
(ft/day)
NA
11.3-25.5
Not characterized
Not characterized
Average Velocity
(ft/day)
NA
0.3 - 0.6
Not characterized
Not characterized
Flow Direction
NA
North
Not characterized
Not characterized
Source: [1,5]
TREATMENT SYSTEM DESCRIPTION
Primarv Treatment Technology
PRB
Supplemental Treatment Technology
None
EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
271:
TIO3.WP6M128-01 .stf
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U.S. Coast Guard Support Center
TREATMENT SYSTEM DESCRIPTION (CONT.)
System Description and Operation PI. 2.51
Table 2. Technical Wall Data
Unit
Continuous Treatment Wall
Flow-Through
Thickness
2 feet
Conductivity
(ft/day)
1,000
Material
Granular
Iron
Vertical
Thickness
18 feet
Source: [1,5]
System Description
• The PRB is a passive, in situ treatment
technology which makes use of natural
groundwater velocity and transport
mechanisms to carry contaminants through
the reaction zone.
• The full-scale PRB consists of 450 tons of
granular zero-valent iron. The reactive
zero-valent iron to dechlorinate TCE to
chloride and ethylene, and reduce
hexavalent chromium to trivalent chromium.
Trivalent chromium forms an insoluble
hydroxide compound and precipitates. The
physical dimensions of the wall are 152 feet
long by 2 feet wide. The reactive media
begins 4 to 8 feet below ground surface and
extends to 24 feet below ground surface.
• The PRB is keyed into an underlying low
conductivity layer within Unit 2, which is
comprised of clayey fine sand to silty clay
and is found at a depth of approximately 22
feet. This material is not classified as an
aquitard; however, chromium and TCE
contamination is primarily found in a highly
conductive zone directly above this unit at a
depth of 16 to 20 feet.
• The required residence time in the
treatment zone for the dechlorination and
reduction reactions has been estimated to
be approximately 21 hours based on the
highest concentration scenario.
• Ten compliance monitoring wells are used
to monitor the treatment wall performance.
Six wells (MW46, MW47, MW49, MW50,
MW52, MW35D) are located downgradient
of the treatment wall. Well MW48 is located
within the treatment wall. Three wells
(MW38, MW48, MW13) are located
upgradient of the treatment wall. Monitoring
well MW52 was added between June 1997
and September 1997 to further monitor
contaminant concentrations downgradient of
the wall. Fifteen additional multi-level
sampling points (135 total sampling points)
have also been installed upgradient and
downgradient of the treatment wall for
research purposes.
System Operation
• Quantity of groundwater treated (gal):
Approximate
Volume Treated
1996-1997
2.6 million gallons
Based on average groundwater velocity of 0.4 ft/day
and dimensions of 152 feet wide and 16 feet flow-
through thickness [2].
Since July 1996, the PRB has been 100%
operational.
Compliance monitoring wells and research
sampling points are monitored for
piezometric head to evaluate groundwater
velocity and flow direction through the PRB.
Operating Parameters Affecting Treatment Cost or Performance
A major operating parameter affecting cost and performance for this technology is the groundwater flow
rate through the treatment wall. The average flow rate through the wall and the required remedial goals
are included in Table 3. In addition, a minimal residence time is required to treat the contaminants to the
cleanup goal levels. For this application, the residence time is 21 hours.
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TREATMENT SYSTEM DESCRIPTION (CONT.)
Operating Parameters Affecting Treatment Cost or Performance fConU
Table 3: Performance Parameters
£/*' f ii -SSI7 f • 4-rv, - U^-sisS1
rr-* ,,\«'*Tarinpeter, •-/.-,
Average Velocity through
Treatment Wall
Remedial Goal (Aquifer
downgradient of the wall)
0.2 - 0.4 ft/day
TCE (5 ug/L)
Cr*6 (0.1 mg/L)
Source: [1,5]
Timeline
A timeline for this remedial project is shown in Table 4.
Table 4: Project Timeline
Start,Date
9/90
6/95
Remedial system designed
9/94
Pilot study initiated
6/96
Construction of full-scale PRB completed (1 day)
6/96
Full-scale PRB begins operation
11/96
Date for initial quarterly monitoring round
11/97
Source: [1]
TREATMENT SYSTEM PERFORMANCE
Cleanup Goals/Standards M. 51
• Cleanup goals for this site are Primary
Drinking Water Standards. Specific
concentrations for target compounds are
included in Table 3. These goals are
applied in monitoring wells downgradient of
the treatment wall.
Treatment Performance Goals M. 5]
The primary goal of the PRB is to reduce
contaminant concentrations in the
groundwater downgradient of the reactive
zone to cleanup goals.
The secondary goal of the PRB is to contain
the contaminated part of the plume
upgradient of the reactive zone.
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TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Assessment T2.7.8.91
• As shown in Figures 2 and 3, Cr*6
concentrations were below the cleanup goal
of 0.1 mg/L in all six downgradient
monitoring wells in both the November 1996
and September 1997 sampling events. Cr*6
concentrations were reported below the
quantification limit (BQL) of 0.0041 mg/L in
all cases.
• As shown in Figures 4 and 5, TCE
concentrations remain above the cleanup
goal of 5 ug/L in four of the six
downgradient wells (MW46, MW49, MW50,
MW52) as of September 1997. In addition,
these figures show that the concentrations
had increased in two of these four wells
(MW49, from 2.8 to 5.5 ug/L and MW50,
from 41 to 548 ug/L; both of these wells are
located adjacent to the wall) over the period
of November 1996 to September 1997. The
other two downgradient wells (MW35D and
MW47) remained below the cleanup goal of
5 ug/L during this time.
• The TCE concentration in MW50 has
fluctuated from the November 1996
(baseline) concentration of 41 ug/L to 3.4
pg/L for the first quarter (of operation), 156
ug/L for the second quarter (of operation),
and 548 ug/L during the September 1997
sampling event. This fluctuation may be
attributed to large amounts of rainfall that
washed into the open trench during
construction. The heavy infiltration rate
may have pushed the organic plume down
or residual contamination in the soils
downgradient of the wall may be leaching
TCE into the aquifer [10].
• Monitoring wells MW13, MW18, MW38,
MW47, MW48, MW49, MW50, MW35D,
MW46 and MW52 are monitored quarterly
for compliance purposes. TCE results from
MW15, MW48, MW50 and MW46 are
shown in Rgure 6, and Cr*6 results from the
same wells are shown in Figure 7.
Performance Data Completeness
Figure 6 shows that TCE concentrations
have decreased in MW48 and MW46 to
approximately 100 ug/L (MW48) and 10
ug/L (MW46), respectively. TCE
concentrations remained relatively constant
at approximately 20 ug/L in MW13, and
increased in MW50 to about 800 ug/L.
Because well MW52 was installed between
the June 1997 and September 1997
sampling event, only one data point is
available. TCE concentrations were
measured at about 500 ug/L for MW52 in
September 1997. Well MW52 is screened
at the same interval as well MW50, and is
located adjacent to the river similar to well
MW46.
Figure 3 shows that Cr*6 concentrations in
MW48, within the treatment wall, remained
relatively constant at approximately 1.0
mg/L. Cr*6 concentrations in MW13,
upgradient of the wall, were higher than the
cleanup goal of 0.1 mg/L, at approximately
3 mg/L.
The pilot study performed in 1994 and 1995
was successful at demonstrating the
effectiveness of the iron treatment wall
technology at this site. The results from the
pilot study led to the selection of a full-scale
reactive wall as the remedy for this RCRA
corrective action.
With respect to the secondary treatment
performance goal of plume contaminant
upgradient of the reactive zone, the data
indicate that the TCE plume may not be
contained. An explanation for the TCE
concentrations found in MW50 and MW52
has not been confirmed.
Ten compliance monitoring wells are
sampled quarterly.
Analyses were performed by the EPA
NRMRL Laboratory and the University of
Waterloo.
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Technology Innovation Office
274
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TREATMENT SYSTEM PERFORMANCE (CONT.)
PASQUOTANK RIVER
MW 46
(SQL)
MW 47 MW 50
(BOL) ^ (SQL)
_a
350
(BOL)
MW 49
(SQL)
ASPHALT PAVEMENT
LEGEND
MW 4^ Monitoring well location.
2.83 mg/L Chromium Concentration
50' '25'
Approximate Scale in Feet
Chromium Concentrations in
Compliance Monitoring Wells
TCE/Chromium Plume Site
United States Coast Guard
Support Center. Elizabeth City
Figure 2. Ct*6 Concentrations in November 1996 [1]
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Office of Solid Waste and Emergency Response
Technology Innovation Office
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TREATMENT SYSTEM PERFORMANCE (CONT.)
PASQUOTANK RIVER
MW 35D
(BQL)
MW 49
(BQL)
IRON WALL
ASPHALT PATCH
,
mg/L
LEGEND
MW 13® Monitoring welt location.
3.27 mg/L Chromium Concentration
(BQL) Below Quantltatlon Limit
20 10 Q 20
Approximate Scale in Meters
September 1997
Chromium Concentrations in
Compliance Monitoring Wells
TCE/Chromium Plume Site
United States Coast Guard
Support Center, Elizabeth City
Figure 3. Ct*6 Concentrations in September 1997 [9]
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TREATMENT SYSTEM PERFORMANCE (CONT.)
PASQUOTANK RIVER
MW 35D
(BQL)
MW 49
2.8 ug/L
IRON WALL
ASPHALT PATCH
MW 13 ,
21.6 ug/
LEGEND
MW 4 0 Monitoring well location.
21.6 ug/L TCE Concentration
50' 25'
501
Approximate Scale in Feet
TCE Concentrations in
Compliance Monitoring Wells
,TCE/Chromium Plume Site
United States Coast Guard
Support Center, Elizabeth City
Figure 4. TCE Concentrations in November 1996 [1]
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Technology Innovation Office
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TREATMENT SYSTEM PERFORMANCE (CONT.)
PASQUOTANK RIVER
MW52
286 ug/L
A
ND
35D
MW 4-7
1.9 ug/L
MW SO
548 (537^ ug/L\ MW 49
ug/L
IRON WALL
ASPHALT PATCH
A «MW 13 ,
A ^* 24.9 ug/L
MW 50 ^
548 (537) ug/L
(BQL)
(ND)
(NS)
20
10
Monitoring well location.
TCE (Duplicate) Concentration
Below Quantitatton Limit
None Detected
Not Sampled
0 20
Approximate Scale in Meters
September 1997
TCE Concentrations In
Compliance Monitoring Wells
TCE/Chromium Plume Site
United States Coast Guard
Support Center, Elizabeth City
Figure 5. TCE Concentrations in September 1997 [9]
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TREATMENT SYSTEM PERFORMANCE (CONT.)
1,000
100
I
0)
o
J
111
Oct-96 Dec-96 Jan-97 Mar-97 Apr-97 Jun-97 Aug-97 Sep-97
— •— MW13
-•-
MW48
-^~
MW50 -^
<— MW46 -5
K— MW52
F/gt/re 6. TCE Concentrations in Five Compliance Wells (1996 - 1997) [1,7,8,9]
o
0.5
0
Oct-96 Dec-96 Jan-97 Mar-97 : Apr-97 Jun-97 Aug-97 Sep-97
• MW13 -•— MW48 —x— MW50 —*— MW46
Figure 7. Cf6 Concentrations in Four Compliance Wells (1996 - 1997) [1,7,8,9]
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Technology Innovation Office
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TREATMENT SYSTEM PERFORMANCE (CONT.)
Performance Data Quality
The QA/QC program used throughout the remedial action met the EPA and the State of North Carolina
requirements. All monitoring was performed using EPA-approved methods, RSKSOP-102, RSKSOP-
146, RSKSOP-147, RSKSOP-175, RSKSOP-179, RSKSOP-181, RSKSOP-183, RSKSOP-184, Method
353.1, Method N-601, SW-846 Method 8240, SW-846 Method 8020 and the vendor did not note any
exceptions to the QA/QC protocols.
TREATMENT SYSTEM COST
Procurement Process
The USCG CEU-Cleveland is the lead for this site. SCEC is responsible for on-site activities and
oversight. The State of North Carolina is responsible for RCRA activities within the state.
Cost Analysis
All costs for design, construction and operation of the treatment system at this site are borne by the
USCG.
Caoltat Costs* FBI
(Cost in 1996 dollars)
Remedial Construction
System Installation $200,000
Site Preparation $100,000
Iron $200,000
Total Remedial Construction $500,000
'Estimated
Operating Costs T61
Monitoring/Analytical $40,0001
Report Preparation $45,0002
Total $85,000
'First annual monitoring and analytical contract.
2Baseline Report.
Other Costs F61
Pilot Program
Remedial Design
State Oversight
$150,000
$60,000
$30,000
Cost Data Quality
Actual capital and operations and maintenance cost data provided by the USCG contact for this site.
Some cost figures provided were estimated based on public sector industry standards.
OBSERVATIONS AND LESSONS LEARNED
The cost for groundwater remediation at this
site over one year was approximately
$585,000 consisting of $500,000 in capital
costs, and $85,000 in operating costs,
corresponding to a unit cost of $225 per
1,000 gallons of groundwater treated.
According to the USCG site contact, by
using a treatment wall to remediate
groundwater contamination, the USCG will
save nearly $4 million in construction and
long-term maintenance costs. This savings
is based on a comparison with a typical
pump and treat system with the following
costs: $500,000 for installation,
$200,000/year for monitoring and
maintenance, and $500,000 for equipment
replacement over a twenty-year operating
life [6]. As this shows, construction and
installation costs are similar in magnitude
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OBSERVATIONS AND LESSONS LEARNED (CONT.)
for this technology when compared with a
typical pump and treat application. However,
operating costs are much less for the treatment
wall technology.
• The results of sampling in November 1996
(after four months of operation) showed that
Cr*6 had been reduced to below the cleanup
goal of 1.0 mg/L in all downgradient
compliance wells. Data from the
September 1997 sampling event showed
that Cr*6 levels remained below the
quantification limit of 0.0041 mg/L.
• As of September 1997, TCE concentrations
had been reduced to below the cleanup goal
of 5 ug/L in two of the six downgradient
compliance wells. While TCE
concentrations were reported below the
cleanup goal in three of these wells in
November 1996, TCE concentration in well
MW49 increased from 2,8 Mg/L to 5.5 ug/L
between sampling events. In addition,
concentrations in well MW50 increased from
41 ug/L to 548 ug/L between November
1996 and September 1997. Possible
reasons for the increase included ongoing
leaching from residual contamination in the
soil and infiltration caused by heavy rainfall.
Because of the limited data available at the
time of this report, mass flux and
cumulative contaminant mass removal
could not be calculated.
REFERENCES
1. Interim Measures Baseline Report, Parsons
Engineering Science, Inc., Gary, NC. April
1997.
2. Interim Measures Workplan, Parsons
Engineering Science, Inc., Gary, NC.
December 1995.
3. Puls, Robert W., CJ. Paul and R.M. Powell,
Remediation of Chromate-Contaminated
Groundwater Using Zero-Valent Iron: Field
Test at USCG Support Center, Elizabeth
City, NC, Proceedings from HSRC/WERC
Joint Conference on the Environment.
4. Puls, Robert W., C.J. Paul and R.M. Powell,
In Situ Immobilization and Detoxification of
Chromate-Contaminated Groundwater
Using Zero-Valent Iron: Field Experiment at
the USCG Support Center, Elizabeth City,
NC, Proceedings from the Great Lakes
Geotechnical and Geoenvironmental
Conference.
Analysis Preparation
5. Phone Conversations with Dr. Robert Puls,
ADA Labs November 25, 1997.
6. Phone Conversations with Mr. James
Vardy, USCG, April 18, 1997.
,7. Interim Measures Quarter 1 Report, Parsons
Engineering Science, Inc., Gary, NC. May
i 1997.
8. Interim Measures Quarter 2 Report, Parsons
Engineering Science, Inc., Gary, NC.
October 1997.
9. Interim Measures Quarter 3 Report, Parsons
Engineering Science, Inc., Gary, NC. March
1998.
! 10. Correspondence between Jim Vardy,
USCG, and Linda Fiedler, USEPA, July 1,
: 1998.
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 Eastern Research
Group, Inc. and Tetra Tech EM Inc. under EPA Contract No. 68-W4-0004.
SS^EPA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
281
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