vvEPA
United States
Environmental Protection
Agency
Surfactant-Enhanced Extraction
Technology Evaluation
EPA-BMBF Bilateral Site
Demonstration
Versuchseinrichtung zur
Grundwasser-und
Altlastensanierung (VEGAS) Facility
Stuttgart, Germany
Innovative Technology
Evaluation Report
-20 mg/1 Xylene
Settling Tank
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Air Stripper
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EPA/540/R-07/004
September 2000
SURFACTANT-ENHANCED
EXTRACTION TECHNOLOGY
EVALUATION
EPA - BMBF BILATERAL SITE
DEMONSTRATION
Versuchseinrichtung zur Grundwasser-und
Altlastensanierung (VEGAS) Facility
STUTTGART, GERMANY
INNOVATIVE TECHNOLOGY EVALUATION REPORT
By
Tetra Tech EM Inc.
1230 Columbia Street, Suite 1000
San Diego, California 92101
Contract No. 68-C5-0037
Work Assignment No. 0-05
Work Assignment Manager
Ann Vega
Land Remediation and Pollution Control Division
National Risk Management Research Laboratory
Cincinnati, Ohio 45268
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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NOTICE
The information in this document has been prepared for the U.S. Environmental Protection Agency's (EPA's)
Superfund Innovative Technology Evaluation program by Tetra Tech EM Inc. under Contract No. 68-C5-
0037. This document has been prepared in support of a bilateral agreement between the EPA and the
Federal Republic of Germany Ministry for Research and Technology. This document has been subject to
the EPA's peer and administrative reviews and has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute an endorsement or recommendation
for use.
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FOREWORD
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the ability
of natural systems to nurture life. To meet this mandate, EPA's research program is providing data and
technical support for solving environmental problems today and building a science knowledge base
necessary to manage our ecological resources wisely, understand how pollutants affect our health, and
prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for investigation of
technological and management approaches for reducing risks from threats to human health and the
environment. The focus of the Laboratory's research program is on methods for the prevention and
control of pollution to air, land, water and subsurface resources; protection of water quality in public
water systems; remediation of contaminated sites and groundwater; and prevention and control of indoor
air pollution. The goal of this research effort is to catalyze development and implementation of
innovative, cost-effective environmental technologies; develop scientific and engineering information
needed by EPA to support regulatory and policy decisions; and provide technical support and information
transfer to ensure effective implementation of environmental regulations and strategies.
This publication has been produced as part of the Laboratory's strategic long-term research plan. It is
published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
Hugh W. McKinnon, Director
National Risk Management Research Laboratory
in
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CONTENTS
NOTICE ii
FOREWORD iii
ACRONYMS AND ABBREVIATIONS vii
CONVERSION TABLE viii
ACKNOWLEDGMENTS ix
EXECUTIVE SUMMARY ES-1
1.0 INTRODUCTION 1
1.1 SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION PROGRAM 3
1.2 BILATERAL AGREEMENT BETWEEN THE UNITED STATES AND
GERMANY ON REMEDIATION OF HAZARDOUS WASTE SITES 5
1.3 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY DESCRIPTION 6
1.4 KEY CONTACTS 8
2.0 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY EFFECTIVENESS 10
2.1 DEMONSTRATION BACKGROUND 10
2.1.1 VEGAS Research Facility 10
2.1.2 Preparation of the Artificial Aquifer 12
2.1.3 Process Description and Planned Operation 12
2.1.4 Demonstration Objectives and Approach 17
2.2 DEMONSTRATION PROCEDURES 20
2.2.1 Sampling and Analysis Program 20
2.2.1.1 Sampling and Measurement Locations 20
2.2.2 Sampling and Analytical Methods 22
2.2.3 Quality Assurance and Quality Control Program 23
2.2.4 Chronology of Process Operations and Changes to the Sampling Program 23
2.3 DEMONSTRATION RESULTS AND CONCLUSIONS 26
2.3.1 Results and Discussion 26
2.3.
2.3.
2.3.
2.3.
2.3.
2.3.
.1 Primary Objective P-l 26
.2 Primary Objective P-2 27
.3 Secondary Objective S-l 31
.4 Secondary Objective S-2 34
.5 Secondary Objective S-3 39
.6 Secondary Objective S-4 39
IV
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CONTENTS (Continued)
2.3.2 Data Quality 41
2.3.3 Conclusions 45
3.0 ECONOMIC ANALYSIS 46
4.0 TECHNOLOGY APPLICATIONS ANALYSIS 47
4.1 FEASIBILITY STUDY EVALUATION CRITERIA 47
4.1.1 Overall Protection of Human Health and the Environment 47
4.1.2 Compliance with ARARs 47
4.1.3 Long-Term Effectiveness and Permanence 48
4.1.4 Reduction of Toxicity, Mobility, or Volume Through Treatment 48
4.1.5 Short-Term Effectiveness 48
4.1.6 Implementability 48
4.1.7 Cost 49
4.1.8 State Acceptance 49
4.1.9 Community Acceptance 49
4.2 APPLICABLE WASTES 49
4.3 LIMITATIONS OF THE TECHNOLOGY 49
5.0 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY STATUS 50
6.0 REFERENCES 51
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FIGURES
1 LOCATION OF VEGAS RESEARCH FACILITY 2
2 PROJECT ORGANIZATION 7
3 CROSS-SECTION OF ARTIFICIAL AQUIFER 11
4 MONITORING WELL CONFIGURATION 13
5 SURFACTANT INJECTION/EXTRACTION SYSTEM 14
6 SURFACTANT RECOVERY SYSTEM 16
7 CONCEPTUAL PLOT OF ANTICIPATED XYLENE MAS S REMOVAL RATES 18
8 SAMPLING AND MONITORING LOCATIONS 21
9 XYLENE MASS REMOVAL RATES DURING THE DEMONSTRATION 30
TABLES
1 CRITICAL MEASUREMENT PARAMETERS 17
2 NONCRITICAL MEASUREMENT PARAMETERS 19
3 ANALYTICAL METHODS: SURFACTANT-ENHANCED EXTRACTION SYSTEM 23
4 XYLENE EXTRACTION RATES IN THE EXTRACTED GROUNDWATER
(SAMPLING LOCATION S4, MONITORING LOCATION Ml) 27
5 XYLENE CONCENTRATIONS IN THE EFFLUENT GROUNDWATER
(SAMPLING LOCATION S2) 32
6 ACUTE TOXICITY OF GROUNDWATER EFFLUENT TO DAPHNIA 34
7 SUMMARY OF THE PROCESS FLOW RESULTS 35
8 SELECTED PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE
INFLUENT GROUNDWATER 36
9 SURFACTANT CONCENTRATIONS OF GROUNDWATER EFFLUENT
(SAMPLING LOCATION S2) 40
10 RESULTS FOR MATRIX SPIKE QC SAMPLES 42
VI
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ACRONYMS AND ABBREVIATIONS
ARARs Applicable or relevant and appropriate requirements
ArGe Arbeitgemeinschaft (focon Probiotec)
ASTM American Society for Testing and Materials
ATTIC Alternative Treatment Technology Information Center
BASF BASF AG
BMBF Federal Republic of German Ministry for Research and Technology
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CERI Center for Environmental Research Information
CLU-IN Clean-up Information (on-line database)
cm Centimeters
°C Degrees Celsius
€ Euro
EPA U.S. Environmental Protection Agency
GC/MS Gas chromatography/Mass Spectrograph
HPLC High performance liquid chromatography
ITER Innovative Technology Evaluation Report
kg Kilogram
LC50 Lethal concentration - 50 percent
L/h Liters per hour
m3 Cubic meters
MCAWW Methods for Chemical Analysis of Water and Wastes
MS/MSD Matrix spike/matrix spike duplicate
m/p-xylene meta-xylene and para-xylene
NPL National Priorities List
NRMRL National Risk Management Research Laboratory
NTIS National Technical Information Service
o-xylene ortho-xylene
ORD U.S. EPA Office of Research and Development
OSWER U.S. Office of Solid Waste and Emergency Response
QA/QC Quality assurance and quality control
QAPP Quality assurance project plan
QC Quality control
RCRA Resource Conservation and Recovery Act
RPD Relative percent difference
SARA Superfund Amendments and Reauthorization Act (of 1986)
SITE Superfund Innovative Technology Evaluation (program)
Superfund Hazardous Substance Response Trust Fund
SVOC Semivolatile organic compound
SW-846 Test Methods for Evaluating Solid Waste
Tauw Tauw Umwelt GmbH Moers
Tetra Tech Tetra Tech EM Inc.
(ig/L Micrograms per liter
VISITT Vendor Information System for Innovative Treatment Technologies
VEGAS Versuchseinrichtung zur Grundwasser-und Altlastensanierung
VOC Volatile organic compound
vn
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To Convert
Centimeters
Centimeters
Cubic meters
Cubic meters
Cubic meters
Degrees Celsius
Hectopascals
Kilograms per square meter
Kilograms
Kilograms per liter
Kilometers
Liters
Liters per hour
Liters per second
Meters
Millimeters
Square meters
CONVERSION TABLE
(Metric to English Units)
Into
Feet
Inches
Cubic feet
Gallons
Cubic yards
Degrees Fahrenheit
Atmosphere
Pounds per square inch, absolute
Pounds
Pounds per cubic foot
Miles (statute)
Gallons
Gallons per minute
Cubic feet (standard) per minute 2.12
Feet
Inches
Square feet
Multiply By
0.0328
0.393
35.0
264
1.31
multiply by 1.80; add
32
0.000986
0.00142
2.21
12.8
0.621
0.265
0.0044
3.278
0.039
10.764
Vlll
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ACKNOWLEDGMENTS
This report was prepared under the direction of Dr. Ronald Lewis of the EPA National Risk Management
Research Laboratory (NRMRL) in Cincinnati, Ohio. This report was prepared by Mr. Roger Argus, Ms.
Elizabeth Barr, and Mr. Steven Geyer of Tetra Tech EM Inc. Ms. Ann Vega of NRMRL, Mr. Burkhard
Heuel-Fabianek of Probiotec, and Dr. Reiner Kurz of Institut Fresenius were contributors to, and
reviewers of, this report.
IX
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EXECUTIVE SUMMARY
This innovative technology evaluation report (ITER) summarizes the results of an evaluation of a
surfactant-enhanced extraction technology. This evaluation was conducted under a bilateral agreement
between the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation
(SITE) program and the Federal Republic of Germany Ministry for Research and Technology (BMBF).
To provide performance data for the evaluation, the surfactant-enhanced extraction system was
demonstrated within an artificial aquifer from February 28 through March 5, 1998 at the
Versuchseinrichtung zur Grundwasser-und Altlastensanierung (VEGAS) research facility in Stuttgart,
Germany. Prior to the demonstration, the artificial aquifer was injected with xylene to create a
contaminant plume for the technology evaluation. During the demonstration, surfactant was injected into
the artificial aquifer, groundwater containing xylene was extracted, and the system was monitored to
assess the effectiveness of the technology.
The Surfactant-Enhanced Extraction Technology
The use of surfactants to enhance in-situ flushing of aquifers for remediation of non-aqueous phase liquid
contaminant plumes has not yet been accepted in Germany because of the limited availability of credible
test data. In order to collect more reliable data, a large-scale test of surfactant-enhanced extraction was
conducted at the VEGAS research facility. The technology demonstrated uses a proprietary surfactant
developed by BASF AG and a surfactant recovery system developed by Tauw Umwelt GmbH Moers.
VEGAS facility personnel installed and operated the treatment system.
The VEGAS research facility was constructed to facilitate the evaluation of remediation technologies. An
artificial aquifer has been constructed at the VEGAS facility to allow for controlled testing of in-situ
treatment technologies. Thirty-one kilograms (kg) of xylene, an organic contaminant with low solubility
in water, was injected into the artificial aquifer and "groundwater" flow was induced to stimulate a
contaminant plume. Groundwater was sampled by the BMBF support contractors, ArGe focon-Probiotec
and Institut Fresenius, with assistance from the EPA support contractor, Tetra Tech EM Inc. (Tetra Tech).
System operating parameters were monitored by VEGAS personnel. All samples were analyzed by the
Institut Fresenius laboratory in Taunusstein. The groundwater effluent from the aquifer was treated using
a conventional water treatment system and recycled into the aquifer. The conventional water treatment
system consisted of a sedimentation tank, a phase separator, a sand filter, and a granular activated carbon
bed.
The proprietary surfactant was designed to enhance the removal of volatile organic compounds (VOCs),
including xylene, from the saturated zone by increasing the partitioning of those compounds into the
ES-1
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groundwater phase, which is then extracted. The above-ground surfactant recovery system was designed
to separate the surfactant from the extracted groundwater for recycling. This system included an air
stripper to remove xylene from the extracted groundwater, a membrane filter to recover surfactant, and a
bioremediation unit to treat permeate from the membrane filter. Therefore, the only wastewater stream
from the system is the treated permeate stream. Five original sample and measurement points were
identified to evaluate the process. Due to a change in the process configuration, sample location S6 and
measurement location M6 were added. Specifically, the Tauw surfactant recovery system was not
operational during the demonstration, as is described in more detail in Section 2.2.2. Therefore, it was
not possible to obtain recycled water from the Tauw surfactant recovery system for reinjection. During
Phase 1 of the process operations (water injection only), this equipment unavailability was overcome by
passing the extracted groundwater through a carbon filter, and then recycling the carbon-treated
groundwater back to the injection well or hydraulic control wells (see Figure 8, Diagram 1).
The groundwater effluent from the artificial aquifer is treated with a conventional water treatment system
at the VEGAS facility and recycled into the artificial aquifer, forming a continuous loop of groundwater
flow. The conventional water treatment system consists of a sedimentation tank, a phase separator, a sand
filter, and a granular activated carbon bed.
Demonstration Conclusions
The conclusions of the surfactant-enhanced extraction technology demonstration are summarized below:
• The xylene mass removal rate increased as a result of the surfactant enhancement. Specifically,
the concentration of xylene in the extracted groundwater increased by a factor of approximately
15 after the injection of the surfactant solution.
• There was no significant increase in the xylene concentration of the groundwater exiting the
artificial aquifer as a result of the surfactant enhancement. Average groundwater effluent xylene
concentrations were 19.8 micrograms per liter ((ig/L) before surfactant injection, 7.7 (ig/L during
surfactant injection, and 2.3 (ig/L following surfactant injection.
• The toxicity results indicate that the extracted groundwater was not sufficiently toxic to kill 50
percent of the Daphniatest organisms, even at no dilution.
• The process operational parameters were as follows: extracted groundwater flow rates ranged
from 116 to 230 liters per hour (L/h); injected groundwater flow rates ranged from 101.4to 112
L/h. Influent groundwater flow rates ranged from 207 to 252 L/h; and effluent groundwater flow
rates ranged from 191 to 315 L/h. The groundwater influent temperature ranged from 18.5 to
19.1 C and the pH ranged from 7.53 to 7.9. The above ground surfactant recycling system was
not operational and was not used during the evaluation; therefore, the surfactant was not
separated and recycled.
ES-2
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• The surfactant concentrations in the effluent groundwater were all less than 0.05 milligrams per
liter (mg/L) for anionic surfactants and less than 0.25 mg/L for nonanionic surfactants. The
treated permeate was not analyzed since the recovery system was not operational.
• The cost of the surfactant provided by BASF was 1.78 Euros (€) per kilogram of surfactant
($2.33 per kilogram assuming a 0.76 € to $1 U.S. exchange rate). Because the surfactant
recovery system was not operational during the demonstration and the ability to recycle surfactant
was not determined, a detailed cost analysis could not be developed.
Technology Applicability
The surfactant-enhanced extraction technology demonstrated at the VEGAS facility accelerated the
removal of xylene from the artificial aquifer. The developer claims that in addition to xylene, the
technology can also remove other non-aqueous phase liquids from the saturated zone. The surfactant-
enhanced extraction technology provides both short-term and long-term protection of human health and
the environment by reducing the concentrations of non-aqueous phase liquid contaminants in the
saturated zone. Because the contaminants are permanently removed, the toxicity, mobility, and volume of
contaminants are also significantly reduced. Minimal adverse impacts to the community, workers, or the
environment are anticipated during site preparation, system installation, and system operation.
Site preparation and access requirements for the technology can be significant. The contamination plume
at the site must be in an aquifer where hydraulic control can be maintained. Operation and maintenance
of the large network of surfactant injection and groundwater extraction wells requires competent technical
and engineering personnel to be available at all times.
ES-3
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1.0 INTRODUCTION
This report documents the findings of an evaluation of a surfactant-enhanced extraction
technology for removal of non-aqueous and volatile organic compounds (VOCs) liquid
contaminants from the saturated zone. This evaluation was conducted under a bilateral agreement
between the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology
Evaluation (SITE) program and the Federal Republic of Germany Ministry for Research and
Technology (BMBF).
The technology was demonstrated from February 28 through March 5, 1998 at the
Versuchseinrichtung zur Grundwasser-und Altlastensanierung (VEGAS) research facility in
Stuttgart, Germany (see Figure 1). The VEGAS research facility was constructed to facilitate the
evaluation of remediation technologies and includes an artificial aquifer to allow for controlled
testing of in-situ technologies. Thirty-one kilograms (kg) of xylene, an organic contaminant with
low solubility in water, was injected into the artificial aquifer at four different locations (and at
four depths), and "groundwater" flow was induced to stimulate a contaminant plume.
The surfactant-enhanced extraction technology was demonstrated at the VEGAS facility to
evaluate its effectiveness in enhancing the removal of a light non-aqueous liquid, specifically
xylene, from the artificial aquifer. Groundwater was sampled by a field team of personnel from
the BMBF support contractors, Institut Fresenius and ArGe focon-Probiotec, with assistance from
the EPA technical support contractor, Tetra Tech EM Inc. (Tetra Tech). System operating
parameters were monitored by VEGAS personnel. All samples were analyzed by the Institut
Fresenius laboratory in Taunusstein. All demonstration activities were conducted in accordance
with the February 1998 quality assurance project plan (QAPP) (Tetra Tech 1998).
The technology demonstration involved three test phases: Phase I - Groundwater flow in the
artificial aquifer with injection and extraction of water only (pump and treat without surfactants);
Phase II - Groundwater flow in the artificial aquifer with surfactant injection and extraction of
groundwater; and Phase III - Groundwater flow in the artificial aquifer with the injection and
extraction of groundwater only to remove residual surfactant. Groundwater samples were
collected and flow rates were measured during each phase. VEGAS personnel conducted routine
monitoring and adjusted the extraction flow rates during the initiation of each phase of the
demonstration. Once VEGAS personnel had initiated each phase, Institut Fresenius personnel
collected the necessary groundwater samples. The decision of when to begin injection of
surfactants was made by VEGAS personnel.
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Location of VEGAS Research Facility
Figure 1
Location of the VEGAS Research Facility
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This report documents the results of the demonstration and provides information that is intended
to be useful to remedial managers, environmental consultants, and other potential technology
users in implementing surfactant-enhanced extraction technologies at contaminated sites. Section
1.0 presents an overview of the SITE program and bilateral agreement, describes the technology,
and lists key contacts. Section 2.0 presents information relevant to the technology's
effectiveness, including contaminated aquifer characteristics and process flow diagrams,
demonstration procedures, and the results and conclusions of the evaluation. Section 3.0 presents
information on the costs associated with applying the technology. Section 4.0 presents
information relevant to the technology's application, including assessment of the technology
related to nine feasibility study evaluation criteria used for decision making in the Superfund
process. Section 4.0 also discusses applicable wastes/contaminants and limitations of the
technology. Section 5.0 summarizes the technology status, and Section 6.0 lists references used
in preparing this report.
1.1 SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION PROGRAM
This section provides background information about the U.S. Superfund law and the EPA SITE
program. Additional information about the SITE program, the surfactant-enhanced extraction
technology, and the technology demonstration can be obtained by contacting the key individuals
listed in Section 1.4.
Past hazardous waste disposal practices and their human health and environmental impacts
prompted the U.S. Congress to enact the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) of 1980 (PL96-510). CERCLA established a
Hazardous Substance Response Trust Fund (Superfund) to pay for handling emergencies at and
cleaning up uncontrolled hazardous waste sites. Under CERCLA, EPA has investigated these
hazardous waste sites and established national priorities for site remediation. The ultimate
objective of the investigations is to develop plans for permanent, long-term site cleanups,
although EPA initiates short-term removal actions when necessary. EPA's list of the nation's
top-priority hazardous waste sites that are eligible to receive federal cleanup assistance under the
Superfund program is known as the National Priorities List (NPL).
As the Superfund program matured, Congress expressed concern over the use of land-based
disposal and containment technologies to mitigate problems caused by releases of hazardous
substances at hazardous waste sites. As a result of this concern, the 1986 reauthorization of
CERCLA, called the Superfund Amendments and Reauthorization Act (SARA), mandates that
EPA "select a remedial action that is protective of human health and the environment, that is cost
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effective, and that utilizes permanent solutions and alternative treatment technologies or resource
recovery technologies to the maximum extent practicable."
In response to this requirement, EPA established the SITE program to accelerate the
development, demonstration, evaluation, and use of innovative technologies for site cleanups.
The SITE program has four goals:
• Identify and remove impediments to development and commercial use of innovative
technologies, where possible
• Conduct demonstrations of the more promising innovative technologies to establish
reliable performance and cost information for site characterization and cleanup decision-
making
• Develop procedures and policies that encourage selection of effective innovative
treatment technologies at uncontrolled hazardous waste sites
• Structure a development program that nurtures emerging technologies
Each year EPA selects the best available innovative technologies for demonstration evaluation. The
screening and selection process for these technologies is based on four factors: (1) the technology's
capability to treat Superfund wastes, (2) expectations regarding the technology's performance and cost,
(3) the technology's readiness for full-scale demonstrations and applicability to sites or problems needing
remedy, and (4) the developer's capability for and approach to testing. SITE program demonstration
evaluations are administered by EPA's Office of Research and Development (ORD) through the National
Risk Management Research Laboratory (NRMRL) in Cincinnati, Ohio.
SITE demonstration evaluations are usually conducted at uncontrolled hazardous waste sites such as EPA
removal and remedial action sites, sites under the regulatory jurisdiction of other federal agencies, state
sites, EPA testing and evaluation facilities, sites undergoing private cleanup, the technology developer's
site, or privately owned facilities. In the case of the surfactant-enhanced extraction technology
demonstration, the VEGAS site was selected cooperatively by EPA and BMBF. The EPA-BMBF
bilateral agreement is discussed in Section 1.2.
SITE and bilateral SITE demonstration evaluations provide detailed data on the performance, cost
effectiveness, and reliability of innovative technologies. These data will provide potential users of a
technology with sufficient information to make sound judgments about the applicability of the technology
to a specific site or waste and to allow comparisons of the technology to other treatment alternatives.
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EPA established the SITE program to accelerate the development, demonstration, and use of innovative
technologies to remediate hazardous waste sites. The demonstration portion of the SITE program focuses
on technologies in the pilot-scale or full-scale stage of development.
The evaluations conducted during SITE technology demonstrations are intended to generate performance
data of known quality. Therefore, sampling and analysis procedures are critical and approved quality
assurance and quality control (QA/QC) procedures are stringently applied as part of all technology
evaluations under SITE.
1.2 BILATERAL AGREEMENT BETWEEN THE UNITED STATES AND GERMANY ON
REMEDIATION OF HAZARDOUS WASTE SITES
In April 1990, EPA and BMBF entered into a bilateral agreement to gain a better understanding of each
country's efforts in developing and demonstrating remedial technologies. The bilateral agreement has the
following goals:
• Facilitate an understanding of each country's approach to remediation of contaminated
sites
• Demonstrate innovative remedial technologies as if the demonstrations had taken place in
each country
• Facilitate international technology exchange
Technologies in the U.S. and in Germany are evaluated under the bilateral agreement. Individual or, in
some cases, multiple remedial technologies are demonstrated at each site. Technology evaluations
occurring in the U.S. correspond to SITE demonstrations; those occurring in Germany correspond to full-
scale site remedial activities and are referred to as bilateral SITE demonstrations. In the case of the U.S.
evaluations, technology evaluation plans are prepared following routine SITE procedures. Additional
monitoring and evaluation measurements required for evaluation of the technology under German
regulations will be specified by the German partners. For the demonstrations occurring in Germany, the
German partners provide all required information to allow the U.S. to develop an EPA NRML QAPP. An
EPA-approved QAPP entitled "Quality Assurance Project Plan for the Surfactant-Enhanced Extraction
Technology Evaluation" and dated February 1998 was prepared for this technology evaluation (Tetra
Tech 1998).
ArGe focon-Probiotec (a partnership of two German environmental consulting firms) was commissioned
by BMBF to compile summary reports for the German technologies and sites, to evaluate the U.S.
demonstration plans, and to facilitate the bilateral agreement on behalf of BMBF. The ArGe focon-
Probiotec technical consulting partnership is not directly involved in the German remedial actions, and
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the partnership does not influence actual site remediation activities. Tetra Tech has been contracted by
the U.S. EPA to provide comprehensive technical support to U.S. evaluations and to coordinate U.S.
activities for bilateral SITE evaluations. The bilateral project organization is presented in Figure 2.
1.3 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY DESCRIPTION
Surfactants and other chemicals have recently been applied as enhancements to conventional soil flushing
technology to accelerate the in situ extraction of contaminants from the saturated zone. In conventional
soil flushing, water is circulated through a contaminated zone to wash out chemical contaminants. The
use of surfactants in the circulated water can increase the mobility or solubility of many organic
contaminants, including particularly non-aqueous phase liquids (NAPLs), further facilitating extraction.
Specifically, surfactants can disperse and solubilize NAPLs through the formation of micelles.
The use of surfactants to enhance in situ soil flushing has not yet been accepted in Germany because
limited credible test data are available for this technology. In order to collect more reliable data, a pilot-
scale demonstration of in situ surfactant-enhanced extraction was conducted at the VEGAS research
facility.
The specific surfactant-enhanced extraction technology evaluated during this bilateral SITE
demonstration employs a proprietary mixture of anionic and nonionic surfactants developed by BASF AG
(BASF) and a surfactant recovery system developed by Tauw Umwelt GmbH Moers (Tauw). The
surfactant recovery system incorporates an air stripper to remove xylene from the extracted water stream,
a membrane filter to recover surfactant, and a bioremediation unit to treat permeate from the membrane
filter. These two components of the surfactant-enhanced extraction technology provide for the
accelerated extraction of NAPL contaminants and for the separation of the surfactant mixture so that it
can be recycled.
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BMBF
PROJECT MANAGER
Dr. Hartmut Pohl
UBA
[TECHNICAL COORDINATOR
Dr. Annett Weiland-Wascher I
VEGAS
PROJECT MANAGER
Mr. Reinhold Josef
ARGE FOCON-PROBIOTECl
PROJECT MANAGER
Mr. Burkhard Heuel-Fabianekl
BASFAG
PROJECT MANAGER
Dr. Michael Ehle
IINSTITUTFRESNIUS
PROJECT MANAGER
Dr. Reiner Kurz
INSTITUTFRESNIUS
QA MANAGER
Dr. Jurgen Ehmann
EPA
PROGRAM MANAGER
Annette Gatchett
EPA
QA COORDINATOR
Ann Vega
EPA
PROJECT MANAGER
Dr. Ronald Lewis
TETRA TECH
QA MANAGER
Dr. Greg Swanson
TETRA TECH
PROJECT MANAGER
Roger Argus
Tetra Tech
Technical Support Staff
Figure 2
Project Organization
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1.4 KEY CONTACTS
Additional information on the surfactant-enhanced extraction technology and the EPA-BMBF bilateral
technology evaluation program can be obtained from the following sources:
Surfactant-Enhanced Extraction Technology
Reinhold Josef
VEGAS Project Manager
Institut fur Wasserbau
Universitat Stuttgart
Pfaffenwaldring 61
70550 Stuttgart
07 11/6857023
EPA-BMBF Bilateral Technology Evaluation Program
Annette Gatchett Bilateral Program Manager
U.S. Environmental Protection Agency
Office of Research and Development
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
513-569-7697
Information on the SITE program is available through the following on-line information clearinghouses:
• The Alternative Treatment Technology Information Center (ATTIC) System (operator: 703-
908-2137) is a comprehensive, automated information retrieval system that integrates data on
hazardous waste treatment technologies into a centralized, searchable source. This data base
provides summarized information on innovative treatment technologies.
• The Vendor Information System for Innovative Treatment Technologies (VISITT) (Hotline:
800-245-4505) data base contains current information on nearly 350 technologies submitted
by nearly 210 developers, manufacturers, and suppliers of innovative treatment technology
equipment and services.
• The Office of Solid Waste and Emergency Response (OSWER) Clean-up Information (CLU-
IN) electronic bulletin board contains information on the status of SITE technology
evaluations. Its web site is www.clu-in.org.
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Technical reports may be obtained by contacting the Center for Environmental Research Information
(CERI), 26 West Martin Luther King Drive in Cincinnati, Ohio 45268 at (513) 569-7562. Additional
information is available on the EPA home page at: www.epa. gov/oerrpage/superfund/sites.
-------
2.0 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY EFFECTIVENESS
This section provides background information and documents the field and analytical procedures as well
as the operation of the process during the demonstration. This section further describes the results and
conclusions of the surfactant-enhanced extraction technology demonstration.
2.1 DEMONSTRATION BACKGROUND
The bilateral SITE evaluation of the surfactant-enhanced extraction technology was conducted at the
VEGAS research facility in Stuttgart, Germany. Xylene, an organic contaminant with low solubility in
water, was injected into an artificial aquifer and groundwater flow was induced to stimulate a contaminant
plume. The surfactant-enhanced extraction technology was then applied to remove the xylene
contaminant from the artificial aquifer.
2.1.1 VEGAS Research Facility
The VEGAS research facility was constructed to facilitate the evaluation of remediation technologies. At
the VEGAS facility, an artificial aquifer has been constructed to allow for controlled testing of in situ
technologies. The artificial aquifer is located in a container that has a length of approximately 9 meters, a
width of approximately 6 meters, and a depth of approximately 4.5 meters. The artificial aquifer within
the container was constructed with inclined layers of sand (fine, medium, and coarse sand) resulting in
hydrologic strata with differing hydraulic permeabilities. The permeability (kf value) of the three kinds
of sand strata have been determined by VEGAS personnel using tracer studies. The value of kf was
determined to be 3.2 x 10-4 meters per second for fine sand, 12.0 x 10-4 meters per second for medium
sand, and 35 x 10-4 meters per second for coarse sand. A cross-section of the artificial aquifer is shown
in the Figure 3.
The container is fitted with 378 sampling and monitoring probes that are available to technology
developers to monitor and control system operation. These probes can be used to measure the height of
the water table, to monitor the hydraulic conditions during the experiment, and to sample the
groundwater.
10
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Direction of Groundwater Flow
Medium
Sand
Coarse
Sand
Injected
Xylene
Medium
Sand
Length in Meters
E
o
Groundwater Elevation
Medium Grained Sand
Coarse Grained Sand
Fine Grained Sand
Contamination Plume
Figure 3
Cross-Section of Artificial Aquifer
-------
"Groundwater" is fed to the container through a permeable wall to maintain a flow of approximately 180
liters per hour. The groundwater table in the container is approximately 3.70 meters from the bottom of
the container. A hydraulic gradient of 0.6 percent is maintained for groundwater flow.
2.1.2 Preparation of the Artificial Aquifer
For the demonstration of the surfactant-enhanced extraction technology, six wells were installed in the
container and labeled MW 1 through MW 6, as shown in Figure 4. The wells labeled MW 1, MW 2, MW
4, and MW 5 were screened across the top two strata. MW 3 was screened across two intervals: the top
strata and the bottom strata. MW 6 was screened from 90 centimeters (cm) to 185 cm below the top to
the well casing.
Approximately 3 months prior to the demonstration, on November 25, 1997, 31 kilograms (kg) of xylene
solution were injected into the aquifer at four different locations between MW 1 and MW 4 and at four
depths (a total of 16 injection points) . After termination of the four injections at the first depth, the
groundwater table was raised to just above the first injection depth. The injection at the next depth was
then made and the groundwater table was raised again. This process was repeated for each of the
specified depths and, after the final xylene injection, the groundwater was raised to result in a saturated
thickness of 3.70 meters above the bottom of the artificial aquifer. Analysis of samples collected from the
groundwater effluent before application of the surfactant-enhanced extraction technology indicated a
relatively constant xylene concentration of about 20 milligrams per liter.
2.1.3 Process Description and Planned Operation
This section describes the system that was installed and the planned mode of operation. It should be
noted that the actual operation changed from these plans as described in Section 2.2.4.
A simplified flow diagram of the surfactant-enhanced extraction system that was installed at the VEGAS
facility is shown in Figure 5. Originally, only five wells were installed in the container (MW 1 through
MW 5); it was planned that the surfactant solution would be injected into MW 1 at approximately 50
liters per hour (L/h) and extracted from MW 2 at 200 L/h. Further, MW 4 and MW 5 were to serve as
hydraulic control wells through the injection of 75 L/h of groundwater into each well. However, it was
later decided to install a sixth well (MW 6) and to alter the planned hydraulic flow scheme as follows:
12
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6.0 m
Length in Meters
-9.0 rrr
Direction of Groundwater Flow
MW5
MW1
MW2
Injected Groundwater/
Surfactant Solution
Influent ^
Groundwater
Effluent
Groundwater
Top View of Artificial Aquifer
Side View of Artificial Aquifer
Medium Grained Sand Fine Grained Sand
Coarse Grained Sand ^ Groundwater Elevation
Figure 4
Monitoring Well Configuration
-------
Groundwater Influent
Conventional
Groundwater
Surfactant Solution
Direction of
Groundwater Flow
MW4
VEGAS-Container
1
MW5
MW1
^/1W2
Tauw
Surfactant
Recovery
System
1 i
Permeate
Discharge
Air
Treatment
Groundwater
Effluent
Source: ArGe focon PROBIOTEC, 1997
Figure 5
Surfactant Injection/Extraction System
-------
• MW 1 and MW 4 - Not used
• MW 2 and MW 5 - Hydraulic control wells
• MW 3 - Extraction well
• MW 6 - Surfactant/groundwater solution injection well
Thus, in the revised hydraulic flow scheme, surfactant solution is injected through MW 6 and extracted
through MW 3. After processing in the surfactant recovery system to remove the extracted xylene and to
separate the surfactant, the extracted groundwater is recycled to supply the hydraulic control wells (MW 2
and MW 5) as well as the injection well (MW 6). This is the flow scheme that was ultimately
implemented at the VEGAS facility.
The above-ground surfactant recovery system includes an air stripper to remove xylene from the extracted
water stream, a membrane filter to recover surfactant, and a bioremediation unit to treat permeate from the
membrane filter. A schematic flow diagram is shown as Figure 6. The only wastewater stream from this
system is the treated permeate stream. The system was designed to meet German discharge limits for the
treated permeate, which are 0.5 milligrams per liter (mg/L) for xylene (a VEGAS facility permit
requirement) and 200 mg/L for surfactants (a self-imposed limit not required by the VEGAS facility
permit).
The groundwater effluent from the artificial aquifer is treated with a conventional water treatment system
at the VEGAS facility and recycled into the artificial aquifer, forming a continuous loop of groundwater
flow. The conventional water treatment system consists of a sedimentation tank, a phase separator, a sand
filter, and a granular activated carbon bed.
The surfactant enhanced extraction technology is implemented in three phases:
• Phase I - groundwater flow in the artificial aquifer with injection and extraction of water only
(pump and treat without surfactants)
• Phase II - groundwater flow in the artificial aquifer with surfactant injection and extraction of
groundwater
• Phase III - groundwater flow in the artificial aquifer with the injection and extraction of water
only to remove residual surfactant
15
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Extraction Water
Flow Rate = 200 l/h
-20 mg/l Xylene
Settling Tank
Extraction Well
Air Stripper
r\ Air from VEGAS -Hall
Recycle to
Hydraulic
Control Wells
Liquid (Water) Streams
Air Streams
Sewage Drain
Concentrate
Figure 6
Surfactant Recovery System
-------
Figure 7 is a conceptual plot of the anticipated contaminant mass removal rates during these three
operational phases. As shown in this figure, contaminant mass removal rates increase dramatically
immediately following the initiation of surfactant injection. After two days of surfactant injection, much
of the extractable contaminant mass is removed from the aquifer and removal rates begin to decline. At
this point, surfactant injection is stopped, and the surfactant as well as residual contaminant is washed out
of the aquifer through continued injection of water alone.
2.1.4 Demonstration Objectives and Approach
Demonstration objectives were selected to provide potential users of the system with the necessary
technical information to assess the applicability of the treatment system to other contaminated sites.
Primary objectives and secondary objectives bilateral were developed and agreed upon for this SITE
demonstration.
The primary objectives and associated critical measurements to evaluate these objectives are listed in
Table 1. The secondary project objectives and associated non-critical measurements required to evaluate
those objectives are listed in Table 2.
TABLE 1. CRITICAL MEASUREMENT PARAMETERS
Primary Objective
Measurement Parameters
PI. Determine whether xylene mass removal rate
increases due to surfactant enhancement.
Flow rate and concentration of xylene in the
extracted groundwater during three test
phases.
P2. Verify that there is no statistically significant
increase in xylene concentrations in groundwater
exiting the artificial aquifer due to surfactant
enhancement.
Concentration of xylene in groundwater
effluent from the artificial aquifer to
determine whether xylene mobilized by the
surfactant is captured in the extracted
groundwater.
17
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128
64
Contaminant
Mass
Removal
Rate
(9/hr)
Initial Surfactant
Injection
Days
Figure 7
Conceptual Plot of
Anticipated Xylene Mass Removal Rates
-------
TABLE 2. NONCRITICAL MEASUREMENT PARAMETERS
Secondary Objective
Measurement Parameter
SI. Evaluate the acute toxicity of the treated
permeate from the surfactant recovery system
and of groundwater effluent from the artificial
aquifer before and after surfactant injection.
LC50 acute tests on samples of surfactant
recycling system permeate and groundwater
effluent.
Toxicity tests on samples of influent groundwater
to provide a baseline.
S2. Document process operating parameters.
Process operating parameters: influent and
effluent groundwater, injected
surfactant/groundwater solution, and extracted
groundwater flow rates; surfactant use rates; and
flow rate of treated permeate.
Documentation of soil and stratigraphic
information, and any operational problems and
difficulties as well as resolutions.
Measurement of physical/chemical groundwater
parameters (temperature; pH; conductivity, and
metals content) in three samples collected from the
influent groundwater to the artificial aquifer.
S3. Document the xylene and surfactant
concentration in the treated surfactant recovery
permeate and surfactant concentration in the
effluent groundwater.
Analysis of samples of treated surfactant recovery
permeate for total xylene according to EPA
method SW-846 8260B (EPA 1996) and
surfactants according to Standard Method 5540C
and D (APHA et al. 1994).
Analysis of samples of groundwater effluent from
the artificial aquifer for surfactants according to
Standard Method 5540C.
S4. Estimate capital and operating costs.
Based on (1) process operating parameters
mentioned above, (2) operating requirements
observed during the evaluation, and (3) capital
costs and operating information provided by
VEGAS and Tauw.
Notes:
EPA
LC50
SW-846
VEGAS
U.S. Environmental Protection Agency
Lethal concentration - 50 percent
Test Methods for Evaluating Solid Waste
Versuchseinrichtung zur Grundwasser-und Altlastensanierung
19
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To perform the measurements needed to meet each of the objectives, samples were collected and analyzed
and field data were recorded using the methods and procedures summarized in the following section.
2.2 DEMONSTRATION PROCEDURES
This section describes the methods and procedures used to collect and analyze samples for the bilateral
SITE evaluation of the surfactant-enhanced extraction technology and discusses the operation of the
process during the demonstration.
2.2.1 Sampling and Analysis Program
This section describes the sampling and analysis program, including sample collection frequencies and
locations.
2.2.1.1 Sampling and Measurement Locations
Sampling and measurement locations were selected based on the configuration of the treatment system
and project objectives. These locations are shown in Figure 8 and include the following sampling ports:
• Location SI: The groundwater influent sampling port
• Location S2: The groundwater effluent sampling port
• Location S3: The surfactant/water injection stream port
• Location S4: The groundwater extraction stream sampling port.
• Location S5: Not used
• Location S6: The conventional groundwater treatment system effluent sampling port
These locations also include the following flow measurement points:
• Location Ml: The extracted groundwater
• Location M2: The injected surfactant/water solution rotameter
• Location M3: The influent groundwater
• Location M4: The effluent groundwater
• Location M5: Not used
• Location M6: The injected water for hydraulic control (MW 5 and MW 2)
20
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Groundwater Influent
Conventional
Groundwater
Treatment
Direction of
Groundwater Flow
MW4
MW6
MW1
MW3
VEGAS-Container
MW5
MW2
Granular
Activated
Carbon Bed
Groundwater
Effluent
Discharge
Diagram 1: Simplified Process Flow Diagram for Phase 1
Conventional
Groundwater
Treatment
Groundwater Influent
(IJI
Activated
Carbon
Filter
Surfactants
Direction of
Groundwater Flow
MW4
MW3
VEGAS-Container
MW 1
t
MW5
MW2
Extracted
Solution
Storage
Tank
Groundwater
Effluent
Diagram 2: Simplified Process Flow Diagram for Phases 2 and 3
Legend
^S1) Sampling location
(Ml) Monitoring location
Source: ArGefocon PROBIOTEC, 1997
Figure 8
Sampling and Monitoring Locations
-------
It should be noted that sample location S6 and measurement location M6 were added to the list of five
original sample points, and sample location S5 and measurement location M5 were deleted due to a
change in the process configuration. Specifically, the Tauw surfactant recovery system was not
operational during the demonstration, as is described in more detail in Section 2.2.2. Therefore, it was
not possible to sample or monitor the permeate or to obtain recycled water from the Tauw surfactant
recovery system for reinjection. During Phase I of the process operations (water injection only), this
equipment unavailability was overcome by passing the extracted groundwater through a carbon filter, and
then recycling the carbon-treated groundwater back to the injection well or hydraulic control wells (see
Figure 8, Diagram 1).
The groundwater effluent from the artificial aquifer is treated with a conventional water treatment system
at the VEGAS facility and recycled into the artificial aquifer, forming a continuous loop of groundwater
flow. The conventional water treatment system consists of a sedimentation tank, a phase separator, a sand
filter, and a granular activated carbon bed.
2.2.2 Sampling and Analytical Methods
This section briefly summarizes the sampling frequencies and procedures as well as analytical methods
used during the evaluation. Details of these sampling procedures and analytical methods are described in
the QAPP (Tetra Tech 1998).
Groundwater samples were collected at the six locations described in the Section 2.2.1. Grab sampling
techniques were employed for all samples taken from the designated sampling ports throughout the
demonstration. Samples of major process streams (the injected and extracted groundwater as well as the
influent and effluent groundwater) were collected approximately every 4 hours. Samples of other
process streams were taken either once per day or once per phase, as specified in the QAPP.
Table 3 lists the analytical procedures used to measure the parameters of interest for the samples collected
during the demonstration. These measurements were made on the samples collected from all locations.
Flow rates were measured by in-line flow meters maintained by VEGAS personnel.
22
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TABLE 3. ANALYTICAL METHODS
SURFACTANT-ENHANCED EXTRACTION SYSTEM
Method Source
SW-846 8260B
EPA/600/4-90/027
SW-846
3010A/6010A
MCAWW 170.1
SW-846 9040B
SW-846 9050
SM 5540C and D
Parametera
VOCs
Acute toxicity
VIetals
Temperature
Name of Method
VOCs by GC/MS: Capillary Column Technique
(preparation method is included in 8260B)
48-hour Static Acute Toxicity Test (Definitive) Using
Ceriodaphnia dubia (C. dubia)
Acid digestion of Aqueous Samples/Inductively coupled Plasma-
Atomic Emission Spectroscopy
Temperature
)H pH Electrometric Measurement
Conductivity [Specific Conductance
Surfactants Surfactants
Notes:
VOCs Volatile Organic Compounds
GC/MS Gas Chromatograph/Mass Spectrograph
MCAWW Methods for Chemical Analysis of Water and Wastes (EPA, 1983)
SW-846 Test Methods for Evaluating Solid Waste (EPA, 1996)
2.2.3 Quality Assurance and Quality Control Program
Quality control checks were an integral part of the bilateral SITE demonstration to ensure that the QA
objectives were met. These checks and procedures focused on the collection of representative samples
absent of external contamination and on the generation of data of acceptable precision and accuracy. The
QC checks and procedures conducted during the demonstration were of two kinds: (1) checks controlling
field activities, such as sample collection and shipping, and (2) checks controlling laboratory activities,
such as extraction and analysis. The results of the field and laboratory QC checks are summarized in
Section 2.3.3.
No project specific field or laboratory audits were conducted during this technology demonstration.
However, general systems audits of Institut Fresenius have been conducted under other bilateral
technology demonstrations.
2.2.4 Chronology of Process Operations and Changes to the Sampling Program
This section summarizes the operation of the surfactant-enhanced extraction system during the bilateral
SITE demonstration. The system was operated from February 28, 1998 at 5:00 p.m. (beginning of Phase
23
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I sampling) to March 5, 1998 at 11:00 a.m. (end of Phase III), for a total of 114 hours. The Tauw
surfactant recovery system was not fully operational, and therefore, sampling of the permeate was not
performed during the demonstration.
As planned, the process was operated and samples were collected in three test phases. The purpose of
Phase I (injection and extraction of water only) was simply to establish steady state operation prior to the
injection of any surfactants. Phase II incorporated the surfactant injection into MW 6 and the enhanced
removal of xylene in the groundwater extracted from MW 3. Phase III returned to water-only injection to
MW 6 to remove the residual surfactant for recovery. The injection and extraction rates during each
phase were set by VEGAS personnel during startup of that phase based on the planned flow rates and
observed operational conditions. Injection into hydraulic control wells MW 2 and MW 5 was maintained
during Phases II and III.
Several changes to the planned operation of the system were implemented during the demonstration by
VEGAS operational personnel. As a result, the on-site personnel from the bilateral SITE sampling team
had to adapt some sampling procedures to meet the demands of the revised process operations. A
chronology of the process operations and descriptions of the changes to planned procedures is included
below. For convenience, all references to the timing of events during the demonstration are hereinafter
referred to by hour and minute using the initiation of Phase I as Time 00:00.
Phase I
Time 00:00. The initial injection rate into MW 6 and the extraction rate from MW 3 were set at
approximately 120 L/h. The water extracted from MW 3 was passed through an activated carbon bed
prior to recycling to MW 6, since the Tauw surfactant recovery system was not yet operational. No
injection into MW 2 or MW 5 was conducted since these wells were for hydraulic control during
surfactant injection.
Time 26:00 to 28:00. To prepare for the surfactant injection, the pumping rate at the extraction well
(MW 3) was increased to approximately 200 L/h. To compensate for this increase and maintain the water
balance in the aquifer container, water from the VEGAS water treatment system was pumped into the
aquifer at MW 2 and MW 5 at a rate of approximately 80 L/h.
Time 49:00. The last Phase I samples were taken.
24
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Phase II
Time 50:00. The pumping configuration was changed by increasing the pumping rate at MW 3 to 200
L/h. As a result of the change in the pumping configuration for the extraction of water, concern arose as
to whether the hydraulic conditions of the aquifer might have been altered. The U.S.-German Bilateral
team decided that additional samples of the extracted groundwater would be collected for xylene analysis
at half-hour intervals from Time 54:30 to Time 60:00 and at 1-hour intervals from Time 60:00 to Time
87:00. The purpose of these samples was to determine whether changes in the hydraulic conditions
affected the xylene concentration at the extraction well and to track the arrival of the surfactant at the
extraction well. This sampling period was designated as Phase Ha, and the samples were labeled
accordingly. Subsequent to this decision, some additional adjustments to the sampling times were
necessary throughout the remainder of Phase II because of various technical modifications (for example,
air in the lines precluding effective sampling, thereby requiring a new sampling point to be installed).
Time 50:20. The injection of surfactant began at MW 6. The surfactant was a 2.2 percent solution of the
BASF proprietary mixture. The volume of surfactant solution was 2.7 cubic meters (m3) and was
contained in a 12 m3 vat in the basement of the VEGAS research facility. The vat employed a stirring
mechanism to keep the solution mixed. A pump was used to inject the surfactant solution and
groundwater into MW 6 at a rate of 100 to 120 L/h.
Time 61:00. Foaming was noted in the water extracted from MW 3. This indicated that the surfactant
had migrated to the extraction well and that the corresponding travel time from the injection well (MW 6)
to the extraction well (MW 3) was approximately 11 hours or less.
Time 70:00. The vat containing the surfactant ran dry. The surfactant had been injected into MW 6 for
approximately 20 hours. The input to the injection well was switched from the surfactant vat to water
from the VEGAS on-site water treatment system. This water was sampled twice (once on March 3 and
once on March 4, 1998) for toxicity tests. No additional samples were collected at MW 6 following the
completion of surfactant addition.
On the third day of operation, Tauw was unable to get their surfactant recovery system to operate as
intended; therefore, no treated permeate samples were collected. All water and surfactant extracted at
MW 3 was collected for processing through the Tauw system and stored in a 12 m3 storage tank in the
basement of the VEGAS research facility. Phase II sampling continued through the fourth day of
operation. During the fifth day of operation, the xylene concentration in a grab sample from MW 3 was
determined by on-site high performance liquid chromatography (HPLC) to be 270 milligrams per liter
(mg/L). Also, water could not be injected into MW 2 so all 80 L/hr of flow for hydraulic control was
being injected into MW 5.
25
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Phase III
Time 110:00. Phase III began on the morning of March 5, 1998. A grab sample collected in mid-
morning from MW 3 was analyzed by on-site HPLC and contained a xylene concentration of 85 mg/L.
This analysis confirmed the beginning of Phase III because this was the first sign of a decreased xylene
concentration in the extracted groundwater. A grab sample also was collected from the extracted
groundwater storage tank; the xylene concentration in this sample was 500 mg/L.
Time 114:00. The 12 m3 storage tank was noted to be full and therefore the demonstration was ended
shortly after. Because Tauw continued to be unable to get their surfactant recovery system to operate as
intended, no treated permeate samples were collected during the demonstration.
2.3 DEMONSTRATION RESULTS AND CONCLUSIONS
This section presents the results of the field measurements and groundwater sampling and analysis
conducted over the 5-day period of the demonstration. This section then describes the conclusions of the
bilateral SITE demonstration of the surfactant-enhanced extraction technology.
2.3.1 Results and Discussion
The results of the bilateral SITE demonstration of the surfactant-enhanced extraction technology are
presented below in relation to the project objectives. In each subsection below, the specific primary or
secondary objective is shown in italics, followed by a discussion of the objective-specific results. Data
quality and conclusions based on these results are presented in Sections 2.3.3 and 2.3.4, respectively.
2.3.1.1 Primary Objective P-l
Determine whether the xylene mass removal rate increases due to surfactant enhancement.
To determine the mass removal rate, samples of groundwater entering and exiting the system were
collected during the three test phases. The mass removal rate was calculated based on the measured flow
rates and xylene concentrations in the extracted groundwater from the artificial aquifer.
The xylene mass removal rates were calculated using the xylene concentration data from samples
collected at S4 and the flow rate of the extracted groundwater measured at Ml.
26
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Specifically, the mass removal rates were calculated by multiplying each xylene concentration by the
flow rate at the time each sample was collected, as listed in Table 4. A graph of the removal rate over all
three phases of the demonstration is shown in Figure 9. The figure shows a mass removal rate pattern that
is consistent with what was expected (Figure 7). However, at Time 76:00, an anomalous decrease in the
xylene concentration from 500 to 126 mg/L was noted. This anomalous data point appears to be related
to an increase in the injection rate of groundwater (from 93 to 189 L/h) at MW 5 at that time due to
plugging in the second hydraulic control well (MW 2).
2.3.1.2 Primary Objective P-2
Verify that there is no statistically significant increase in xylene concentrations in groundwater exiting
the artificial aquifer due to surfactant enhancement.
TABLE 4. XYLENE EXTRACTION RATES IN THE EXTRACTED GROUNDWATER
(SAMPLING LOCATION S4, MONITORING LOCATION Ml)
Sample
Description
Phase I
1-1-1-1
Phase I
1-1-1-2
Phase I
1-1-1-3
Phase I
1-1-1-4
Phase I
1-1-1-5
Phase I
1-1-1-6
Phase I
1-1-1-7
Phase I
1-1-1-8
Phase I
1-1-1-9
Phase I
1-1-1-10
Phase Ha
2a-l-l-l
Phase Ha
2a-l-l-2
Phase Ha
2a-l-l-3
Sampling Date
and
Time
2/28/98
00:00
2/28/98
04:00
3/1/98
07:30
3/1/98
15:00
3/1/98
20:00
3/1/98
25:00
3/1/98
30:00
3/2/98
39:00
3/2/98
44:00
3/2/98
49:00
3/2/98
54:30
3/3/98
55:00
3/3/98
55:30
Total Xylene
Concentration
(HS/L)
33.0
32.5
32.6
35.6
36.7
35.9
27.6
26.1
26.8
26.9
28.7
26.3
26.7
Flow Rate
(L/h)
144
143
131
130
121
116
206
192
192
184
202
202
202
Xylene Mass
Removal Rate
(Hg/h)
4,750
4,650
4,270
4,630
4,440
4,160
5,690
5,010
5,150
4,950
5,800
5,310
5,390
27
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TABLE 4. XYLENE EXTRACTION RATES IN THE EXTRACTED GROUNDWATER (SAMPLING
LOCATION S4, MONITORING LOCATION Ml)
Phase Ha
2a-l-l-4
Phase Ha
2a-l-l-5
Phase Ha
2a-l-l-6
Phase Ha
2a-l-l-7
Phase Ha
2a-l-l-7
Phase Ha
2a-l-l-8
Phase Ha
2a-l-l-9
Phase Ha
2a-l-l-10
Phase Ha
2a-l-l-ll
Phase Ha
2a-l-l-12
Phase Ha
2a-l-l-13
Phase Ha
2a-l-l-14
Phase II
2-1-1-1
Phase II
2-1-1-2
Phase II
2-1-1-3
Phase II
2-1-1-4
Phase II
2-1-1-5
Phase II
2-1-1-6
Phase II
2-1-1-7
Phase II
2-1-1-8
Phase II
2-1-1-9
Phase II
2-1-1-10
Phase II
2-1-1-11
Phase II
2-1-1-12
Phase II
2-1-1-13
Phase II
2-1-1-14
Phase II
2-1-1-15
3/3/98
56:00
3/3/98
56:30
3/3/98
57:00
3/3/98
57:30
3/3/98
58:00
3/3/98
58:30
3/3/98
59:00
3/3/98
59:30
3/3/98
60:00
3/3/98
61:00
3/3/98
62:00
3/3/98
63:00
3/3/98
64:00
3/3/98
66:00
3/3/98
68:00
3/3/98
70:00
3/3/98
72:00
3/3/98
74:00
3/3/98
76:00
3/3/98
78:00
3/4/98
80:00
3/4/98
82:00
3/4/98
84:00
3/4/98
86:00
3/4/98
88:00
3/4/98
90:00
3/4/98
92:00
27.5
14.4
27.3
28.1
28.4
25.0
28.1
27.0
27.1
28.3
28.0
31.0
64.5
184
387
506
486
128
567
534
506
516
453
397
274
294
239
200
200
200
203
202
202
203
202
203
204
230
181
209
211
209
214
226
227
223
224
217
219
219
217
214
219
216
5,500
2,880
5,460
5,700
5,740
5,050
5,700
5,450
5500
5,770
6,440
5,610
13,500
38,800
80,900
108,000
110,000
29,000
12,700
120,000
110,000
113,000
99,200
86,100
58,600
64,400
51,600
28
-------
TABLE 4. XYLENE EXTRACTION RATES IN THE EXTRACTED GROUNDWATER (SAMPLING
LOCATION S4, MONITORING LOCATION Ml)
Phase II
2-1-1-16
Phase II
2-1-1-17
Phase II
2-1-1-18
Phase II
2-1-1-19
Phase II
2-1-1-20
Phase II
2-1-1-21
Phase II
2-1-1-22
Phase II
2-1-1-23
Phase III
3-1-1-1
Phase III
3-1-1-2
Phase III
3-1-1-3
Phase III
3-1-1-4
Phase III
3-1-1-5
Phase III
3-1-1-6
Phase III
3-1-1-7
Phase III
3-1-1-8
Phase III
3-1-1-9
Phase III
3-1-1-10
Phase III
3-1-1-11
Phase III
3-1-1-12
3/4/98
94:00
3/4/98
96:00
3/4/98
98:00
3/4/98
100:00
3/4/98
102:00
3/5/98
104:00
3/3/98
106:00
3/3/98
108:00
3/5/98
111:00
3/5/98
112:00
3/5/98
114:00
3/5/98
116:00
3/5/98
118:10
3/5/98
120:00
3/5/98
122:00
3/5/98
126:00
3/6/98
130:00
3/6/98
134:00
3/6/98
138:00
3/6/98
142:00
207
143
121
113
98.0
95.0
91.1
85.6
81.0
70.4
69.5
64.5
63.3
59.9
53.3
49.8
45.5
44.7
39.6
39.5
215
220
218
216
207
218
230
181
221
221
218
218
213
213
213
212
200
200
200
194
44,500
31,500
26,400
24,400
20,300
21,400
21,000
15,500
17,900
15,600
15,200
14,100
13,500
12,800
11,400
10,600
9,100
8,940
7,920
7,660
Notes:
ug/L micrograms per liter
L/h liters per hour
ug/h micrograms per hour
29
-------
Xylene Mass Removal Rates During the Demonstration
Extraction Well S4
140000 -r
120000 --
100000 --
•S 80000 -
60000
40000 --
20000 --
Time in Hours
Figure 9
30
-------
This objective was to be achieved by calculating a test statistic to determine the probability of observing
that particular result or one more extreme. However, the xylene concentrations detected during Phase I of
the demonstration, which were expected to serve as a constant baseline for which to compare the data
obtained during Phase II and Phase III, were decreasing throughout Phase I and were not constant to serve
for a basis of comparison.
Therefore, this objective, to show a statistical significance in the change of xylene concentrations in
groundwater exiting the artificial aquifer, could not be conducted. The data obtained to achieve this
objective are presented in Table 5. The range and average xylene concentration during each phase of the
demonstration was as follows:
• Phase I (steady state without surfactant addition): range of from <1 to 43.5 (ig/L, with an average
concentration of 19.8 (ig/L (assuming a value equal to the detection limit for results below the
detection limit)
• Phase II (surfactant addition): range of from 3.8 to 12.9 (ig/L, with an average concentration of 7.7
• Phase III (post-surfactant addition): range of from <1 to 4.6 (ig/L, with an average concentration of
2.3 (ig/L (assuming a value equal to the detection limit for results below the detection limit)
These results show that the xylene concentration was actually decreasing in the effluent groundwater
during the surfactant addition and post-surfactant addition phases. These results appear to reflect the
degree of success achieved in removing the xylene mass from the artificial aquifer. With less xylene
mass present during the surfactant addition and post-surfactant addition phases, there was apparently less
mobilization into the groundwater flow exiting the artificial aquifer. This explanation is supported by the
fact that the effluent xylene concentrations declined with time over both Phase II and Phase III of the
demonstration.
Even though a statistical test could not be calculated on the data, the data obtained during Phase II and
Phase III does not show an upward trend. No notable increase was observed between Phase II and Phase
III. Therefore, the hydraulic control wells appeared to have functioned as planned.
2.3.1.3 Secondary Objective S-l
Evaluate the acute toxicity of the treated permeate from the surfactant recovery system and of
groundwater effluent from the artificial aquifer before and after surfactant injection.
31
-------
TABLE 5. XYLENE CONCENTRATIONS IN THE EFFLUENT GROUND WATER
(SAMPLING LOCATION S2)
Phase Sample Time
Phase I
0:00
Phase I
4:00
Phase I
7:30
Phase I
15:00
Phase I
20:00
Phase I
25:00
Phase I
30:00
Phase I
39:00
Phase I
44:00
Phase I
49:00
Phase II
64:00
Phase II
68:00
Phase II
72:00
Phase II
76:00
Phase II
80:00
Phase II
84:00
Phase II
88:00
Phase II
92:00
Phase II
96:00
Phase II
100:00
Phase II
104:00
Phase II
108:00
Phase III
111:00
Phase III
112:00
Sampling Date
2/28/98
2/28/98
3/1/98
3/1/98
3/1/98
3/1/98
3/1/98
3/2/98
3/2/98
3/2/98
3/3/98
3/3/98
3/3/98
3/3/98
3/4/98
3/4/98
3/4/98
3/4/98
3/4/98
3/4/98
3/5/98
3/5/98
3/5/98
3/5/98
Total Xylene Concentration
(HS/L)
<1
<1
<1
<1
39.6
43.5
39.8
29.9
24.3
17.7
12.9
12.9
11.4
9.7
9.1
6.3
5.4
6.7
5.0
4.6
3.8
4.6
4.6
NA
32
-------
Phase III
114:00
Phase III
118:00
Phase III
122:00
Phase III
126:00
Phase III
130:00
Phase III
134:00
Phase III
138:00
Phase III
142:00
3/5/98
3/5/98
3/5/98
3/5/98
3/6/98
3/6/98
3/6/98
3/6/98
3.5
3.2
2.6
2.5
1.2
1.1
<1
1.1
Notes:
Hg/L
Microgram per liter
The results of the evaluation of acute toxicity of groundwater effluent before and after surfactant injection
are presented in Table 6. The toxicity results indicate that the extracted groundwater was not sufficiently
toxic to kill 50 percent of the Daphnia test organisms, even at no dilution. An evaluation of the treated
permeate was not performed since the surfactant recovery system was not operational.
33
-------
TABLE 6. ACUTE TOXICITY OF GROUNDWATER EFFLUENT TO DAPHNIA
Sample Phase and Time
Phase I
00:00
Phase II
64:00
Phase II
76:00
Phase II
80:00
Phase II
104:00
Phase III
111:00
Phase III
130:00
Sampling Date
2/28/98
3/3/98
3/3/98
3/4/98
3/5/98
3/5/98
3/6/98
Effluent Concentration for
50% Mortality (%)
>100
>100
>100
>100
>100
>100
>100
Notes:
% Percent
2.3.1.4 Secondary Objective S-2
Document process operating parameters.
Various process operating parameters were measured to document system conditions throughout the
demonstration. Process flow rates are presented in Table 7. A summary of other process flow rates is
given below:
• The injected groundwater flow rate ranged from 101.4 to 112 L/h; the extracted groundwater flow
rate ranged from 116 to 230 L/hr
• The influent groundwater flow rate ranged from 207 to 252 L/h; the effluent groundwater flow
rate ranged from 191 to 315 L/h.
Additionally, selected groundwater physical and chemical characteristics (temperature, pH, conductivity
and metals) were monitored for the influent groundwater to the artificial aquifer. The results of these
measurements are presented in Table 8.
34
-------
TABLE 7
SURFACTANT CONCENTRATIONS
OF GOUNDWATER INFLUENT
Sample Description
1-4-X-l
2-4-X-l
2-4-X-3
2-4-X-4
2-4-X-6
2-4-X-7
2-4-X-9
2-4-X-l 1
3-4-X-3
3-4-X-5
3-4-X-8
3-4-X-10
Sampling Date
2/28/98
3/3/98
3/3/98
3/3/98
3/4/98
3/4/98
3/4/98
3/5/98
3/5/98
3/5/98
3/6/98
3/6/98
Anionic Surfactants
(mg/L)
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
Nonanionic
Surfactants
(mg/L)
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
<0.25
• Note: Acute toxicity values expressed in the mortality of species for each tested;
Fish, Daphnia, and Leuchtbakterien repectively.
-------
TABLE 8. SELECTED PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE INFLUENT GROUNDWATER
Sample Description:
Sample Date:
Temperature ( C)
pH
Surfactants, anionic
(mg/L)
Surfactants, nonionic
(mg/L)
Phase I
Groundwater
Effluent
(S2)
03/01/98
18.5
7.53
<0.05
<0.25
Phase I
Injected
Groundwater
(S3)
03/01/98
18.5
7.53
<0.05
<0.25
Phase II
Injected
Groundwater
(S3)
03/04/98
19.1
7.9
<0.05
<0.25
Phase II
Injected into
Hydraulic Control
Wells (S6)
03/04/98
19.1
7.9
<0.05
<0.25
Phase III
Injected
Groundwater
(S3)
03/05/98
18.6
7.83
<0.05
0.27
Phase III
Groundwater Injected into
Hydraulic Control Wells
(S6)
03/05/98
18.6
7.83
<0.05
<0.25
Metals
Al (ug/L)
Sb (ug/L)
As (ug/L)
Ba (ug/L)
Be (ug/L)
Cd (ug/L)
Cr(ug/L)
Co (ug/L)
Cu (ug/L)
Fe (ug/L)
Pb (ug/L)
Li (ug/L)
45
<30
<50
172
<1
<4
<10
<10
11
484
<40
<5
<40
<30
<50
83
<1
<4
<10
<10
<10
<10
<40
<5
<40
<30
<50
159
<1
<4
<10
<10
<10
851
<40
7
65
<30
<50
64
<1
<4
<10
<10
<10
<10
<40
<5
<40
<30
<50
143
<1
<4
<10
<10
<10
864
<40
7
<40
<30
<50
66
<1
<4
<10
<10
<10
<10
<40
5
36
-------
TABLE 8. SELECTED PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE INFLUENT GROUNDWATER (Continued)
Sample Description:
Sample Date:
Mn (ng/L)
Mo (jig/L)
Ni (ng/L)
Se (ng/L)
Ag (ng/L)
Sr (,ig/L)
TI (ng/L)
V (ng/L)
Zn(ng/L)
Na (mg/L)
K (mg/L)
Mg (mg/L)
Ca (mg/L)
Ammonia (mg/L)
F (mg/L)
Cl (mg/L)
NO2 (mg/L)
NO3 (mg/L)
HCO3 (mg/L)
Phase I
Groundwater
Effluent
(S2)
03/01/98
849
<10
15
<80
<10
541
<40
<10
15
153
12.5
8.9
97.1
<0.02
0.18
264
0.02
0.3
210
Phase I
Injected
Groundwater
(S3)
03/01/98
7
<10
<15
<80
<10
465
<40
<10
370
154
12.4
8.5
84.2
0.10
0.17
262
1.2
1.2
177
Phase II
Injected
Groundwater
(S3)
03/04/98
676
<10
<15
<80
<10
514
<40
<10
5
151
12.7
8.4
95.5
0.26
0.18
263
0.02
O.3
197
Phase II
Injected into
Hydraulic Control
Wells (S6)
03/04/98
<5
<10
<15
<80
<10
419
<40
<10
2
115
9.1
7.2
73.0
O.02
0.15
186
0.02
0.5
177
Phase III
Injected
Groundwater
(S3)
03/05/98
552
17
<15
<80
<10
504
<40
<10
<2
155
12.2
8.5
92.0
0.15
0.18
257
0.02
O.3
195
Phase III
Groundwater Injected into
Hydraulic Control Wells
(S6)
03/05/98
<2
<10
<15
<80
<10
423
<40
<10
7
112
9.7
7.6
75.0
O.02
0.16
187
0.02
0.7
176
37
-------
Sample Description:
Sample Date:
SO4 (mg/L)
Phase I
Groundwater
Effluent
(S2)
03/01/98
94
Phase I
Injected
Groundwater
(S3)
03/01/98
85
Phase II
Injected
Groundwater
(S3)
03/04/98
93
Phase II
Injected into
Hydraulic Control
Wells (S6)
03/04/98
66
Phase III
Injected
Groundwater
(S3)
03/05/98
89
Phase III
Groundwater Injected into
Hydraulic Control Wells
(S6)
03/05/98
68
Notes:
C
mg/L
Hg/L
Degrees Celsius
Milligrams per liter
Micrograms per liter
38
-------
As shown in Table 8, the influent groundwater was relatively consistent in its physical and chemical
characteristics. Specifically, the groundwater influent temperature ranged from 18.5 Cto 19.1 C and the
pH ranged from 7.53 to 7.9. Major cations and anions also showed little variability.
2.3.1.5 Secondary Objective S-3
Document the xylene and surfactant concentrations in the treated surfactant recovery permeate and
surfactant concentration in effluent groundwater.
The results of the surfactant concentration measurements for samples of the groundwater effluent are
presented in Table 9. As shown in this table, neither anionic nor nonionic surfactants were detected in
any of the groundwater effluent samples. Thus, the injection of groundwater into the hydraulic control
wells appears to have been successful in excluding surfactant from the groundwater effluent.
Results were not available for the treated permeate since the surfactant recovery system was not
operational during the demonstration.
2.3.1.6 Secondary Objective S-4
Estimate capital and operating costs.
Because the surfactant recovery system was not operational during the demonstration and the ability to
recycle surfactant was not determined, a detailed cost analysis of the surfactant-enhanced extraction
technology could not be developed. The cost of the surfactant provided by BASF was 3.50 DM per
kilogram of surfactant ($1.82 per kilogram assuming a 1.92 DM to $1 U.S. exchange rate). A further
discussion of cost information is provided in Section 3.0.
39
-------
TABLE 9. SURFACTANT CONCENTRATIONS IN GROUND WATER EFFLUENT
(SAMPLE LOCATION S2)
Sample Phase and Time
Phase I
00:00
Phase II
64:00
Phase II
72:00
Phase II
76:00
Phase II
84:00
Phase II
88:00
Phase II
96:00
Phase II
104:00
Phase III
114:00
Phase III
122:00
Phase III
134:00
Phase III
142:00
Sampling Date
2/28/98
3/3/98
3/3/98
3/3/98
3/4/98
3/4/98
3/4/98
3/5/98
3/5/98
3/5/98
3/6/98
3/6/98
Anionic Surfactants
(mg/L)
0.05
<0.05
0.05
0.05
O.05
0.05
O.05
O.05
0.05
O.05
O.05
0.05
Nonanionic
Surfactants
(mg/L)
0.25
O.25
0.25
0.25
O.25
0.25
O.25
O.25
0.25
O.25
O.25
0.25
Notes:
mg/L Milligram per liter
< Less than
40
-------
2.3.2 Data Quality
This section summarizes the results for quality control samples collected and analyzed during the
demonstration and addresses associated data quality issues. The results of this assessment were used to
produce the known, defensible information employed to define the investigation findings and to draw
conclusions.
The primary QC samples processed in relation to the sole critical analysis (xylene in groundwater
samples) included trip blanks and field blanks, matrix spike/matrix spike duplicates (MS/MSDs). Xylene
concentrations reported in previous sections for evaluation of process performance are total xylenes
concentrations, measured as the sum of ortho-xylene (o-xylene) and combined meta-xylene and para-
xylene (m/p-xylene). For the quality control samples, o-xylene and m/p-xylene are reported separately.
Field blanks and trip blanks were collected to monitor whether field techniques or sample shipping
potentially introduced xylene into the field samples. All three trip blanks and all three field blanks had
concentrations of <1 (ig/L for both o-xylene and m/p-xylene. Therefore, field techniques and sample
shipping did not introduce measurable concentrations of xylenes.
One extracted groundwater MS/MSD sample was analyzed in association with each of the sampling
events to assess the precision and accuracy of the xylene results in the groundwater matrix. Table 10 lists
the results of these MS/MSD analyses. In general, these results were within the acceptance criteria for
recovery of xylene and relative percent difference (RPD) of the duplicate results. Specifically, only three
recoveries out of 22 pairs of MS/MSD sample results were outside of the acceptance criteria for the
associated percent recoveries. Of those three samples, two samples were also outside of the RPD
acceptance criteria. Further, none of the excursions outside of the acceptance criteria were extraordinary
or appeared to indicate anything other than random errors. Therefore, these MS/MSD results indicate that
generally acceptable laboratory precision and accuracy were achieved for the xylene determinations in
groundwater samples.
41
-------
TABLE 10. RESULTS FOR MATRIX SPIKE QC SAMPLES
Sample
Phase, Time
Phase I, 08:00
Phase II, 88:00
Phase III, 112:00
Phase III, 122:00
Phase I, 15:00
Phase II, 80:00
Phase III, 114:00
Phase I, 15:00
Phase II, 72: 00
Parameter
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
Sample
(HS/L)
<1
<1
1.6
<1
<1
<1
<1
<1
3.4
1.5
29.2
16.4
10.1
7.6
5.5
2.6
2.2
MS
(HS/L)
55.16
27.1
25.1
12.02
49.84
24.3
26.06
12.58
42.66
23.38
58.3
27.9
78.6
38.74
54.78
26.76
53.46
MSD
(HS/L)
56.42
26.56
24.78
11.78
50.42
24.18
25.16
11.92
49.86
24.74
55.12
26.94
53.3
25.78
55.92
26.82
54.06
Spike
(HS/L)
50.8
24.4
25.44
12.2
50.88
24.4
25.44
12.2
50.88
24.4
50.88
24.4
50.88
24.44
50.88
24.4
50.88
Spike
Recovery
108.1
110.7
97.4
97.7
97.9
99.4
102.3
103.0
82.5
94.6
103.1
100.9
150.5*
152.6*
104.2
107.5
104.2
RPD
(%)
2.3
2.0
1.3
2.0
1.2
0.5
3.5
5.4
15.6
5.7
5.6
3.5
38.4
40.2
1.1
0.2
1.1
QC limits
(%R)
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
QCRPD
(%)
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
42
-------
TABLE 10. RESULTS FOR MATRIX SPIKE QC SAMPLES
Phase III, 118:00
Phase I, 7: 30
Phase I, 39:00
Phase I, 44:00
Phase II, 60:00
Phase II, 76:00
Phase II, 78:00
Phase II, 94:00
Phase II, 102:00
Phase II, 94:00
Phase III, 122:00
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
o-xylene
m/p-xylene
0.2
0.9
0.4
13.4
2.9
10.8
2.2
11.1
2.4
238.2
45.1
123.9
23.6
16.0
3.1
44.0
9.3
9.6
1.7
18.3
3.7
10.2
25.2
49.46
24.3
15.38
5.94
11.86
5.0
26.1
12.48
69.62
22.02
46.24
17.08
33.68
15.5
39.1
17.24
25.78
12.36
26.6
12.82
27.78
25.9
53.3
25.78
15.66
6.04
11.8
5.22
27.06
13.26
68.75
21.96
45.06
16.56
32.98
15.06
35.9
15.92
24.98
12.44
26.78
13.02
25.62
24.4
50.88
24.4
12.72
6.1
12.72
6.1
25.44
12.2
25.44
12.2
25.44
12.2
25.44
12.2
25.44
12.2
25.44
12.2
25.44
12.2
25.44
107.5
96.9
103.1
99.8
88.0
76.3
74.6
93.8
98.4
86.4
106.6
84.3
121.9
119.9
121.9
119.9
126. lf
93.8
98.4
90.2
98.9
101.1
0.2
7.5
2.8
5.9
1.8
0.5
4.5
3.6
6.1
1.3
0.3
2.6
2.9
2.1
2.9
8.6
7.9
3.3
0.8
0.7
1.5
8.1
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
75-125
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
<20
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TABLE 10. RESULTS FOR MATRIX SPIKE QC SAMPLES
Phase III,
o-xylene
m/p-xylene
o-xylene
2.0
20.6
4.3
13.5
27.72
12.88
13.28
27.46
12.54
12.2
25.44
12.2
107.3
92.88
98.4
1.7
0.9
2.6
75-125
75-125
75-125
<20
<20
<20
Notes: and bold font indicates QC results outside of acceptancea criteria (75-125% recovery and/or <20%RPD).
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2.3.3 Conclusions
The results of the surfactant-enhanced extraction bilateral SITE demonstration are discussed above in
relation to the two primary and four secondary objectives. The corresponding conclusions of this
evaluation are summarized below:
• The xylene mass removal rate increased as a result of surfactant injection. The concentration of
xylene in the extracted groundwater increased by a factor of approximately 15 after the injection
of the surfactant solution. The graph of the xylene mass removal rate (Figure 9) illustrates the
increase in xylene mass removal rate after injection of the surfactant.
• There was no significant increase in xylene concentration exiting the artificial aquifer due to
surfactant enhancement. Groundwater effluent xylene concentrations during: Phase I (steady
state without surfactants) ranged from <1 to 43.5 (ig/L with an average concentration of 19.8
(ig/L; Phase II (non steady state with surfactants) ranged from 3.8 to 12.9 (ig/L with an average
concentration of 7.7 (ig/L; and Phase III (steady state, post surfactant injection) ranged from <1 to
4.6 (ig/L with an average concentration of 2.3 (ig/L.
• The toxicity results indicate that the extracted groundwater was not sufficiently toxic to kill 50
percent of the Daphniatest organisms, even at no dilution.
• The process operation parameters were as follows. The extracted groundwater flow rates ranged
from 116 to 230 L/h and injected groundwater (M2) flow rates ranged from 101.4 to 112 L/h.
The influent groundwater (M3) flow rate ranged from 207 to 252 L/h and the effluent
groundwater (Location M4) flow rate ranged from 191 to 315 L/h. The following changes were
made to the planned operation: 1) A revised flow scheme was utilized and Wells MW 1, 2, and 4
were not used; a new well (MW 6) was installed and utilized as the groundwater/surfactant
injection well, 2) The above ground surfactant recovery system was not operational. The
groundwater influent samples temperature ranged from 18.5 to 19.1 C; and pH ranged from 7.53
to 7.9.
• The surfactant concentrations in the effluent groundwater were all less than 0.05 mg/L for anionic
surfactants and less than 0.25 mg/L for nonanionic surfactants. The treated permeate was not
analyzed since the recovery system was not operational.
• The cost of the surfactant provided by BASF was 1.78 Euros (€) per kilogram of surfactant
($2.33 per kilogram assuming a 0.76 € to $1 U.S. exchange rate). Because the surfactant
recovery system was not operational during the demonstration and the ability to recycle the
surfactant was not determined, a detailed cost analysis could not be developed.
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3.0 ECONOMIC ANALYSIS
This section presents available cost information for the surfactant-enhanced extraction technology based
on data provided by Tauw Umwelt GmbH Moers and BASF AG.
Because the surfactant recovery system was not operational during the demonstration and the ability to
recycle surfactant was not determined, a detailed cost analysis of the surfactant-enhanced extraction
technology could not be developed.
Cost information was solicited from Tauw Umwelt GmbH Moers and BASF AG. The only cost
information provided was that provided by BASF AG for the surfactant. BASF indicated that the cost of
the surfactant was 1.78 Euros (€) per kilogram of surfactant ($2.33 per kilogram assuming a 0.76 € to $ 1
U.S. exchange rate).
Although treatment costs were not independently estimated, the following cost categories (Evans 1990)
should be considered when evaluating the potential cost of treating groundwater using the surfactant-
enhanced extraction technology:
• Site preparation
• Permitting and regulatory requirements
• Capital equipment
• Startup
• Labor
• Consumables and supplies
• Utilities
• Effluent treatment and disposal
• Residuals and waste shipping and handling
• Analytical services
• Maintenance and modifications
• Demobilization
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4.0 TECHNOLOGY APPLICATIONS ANALYSIS
This section evaluates the general applicability of the surfactant-enhanced extraction technology to
remediation of the saturated zone at contaminated sites. Information presented in this section is intended
to assist decision makers in screening specific technologies for a particular cleanup situation. This section
presents the advantages, disadvantages, and limitations of the technology and discusses factors that have a
major impact on the performance and cost of the technology. The analysis is based both on the
demonstration results and on available information from other applications of the technology.
4.1 FEASIBILITY STUDY EVALUATION CRITERIA
This section assesses the surfactant-enhanced extraction technology against the nine evaluation criteria
used for conducting detailed analyses of remedial alternatives in feasibility studies under CERCLA (EPA
1988).
4.1.1 Overall Protection of Human Health and the Environment
The surfactant-enhanced extraction technology provides both short-term and long-term protection of
human health and the environment by removing organic contaminants from the saturated zone. Treated
groundwater is recycled to the aquifer, thereby limiting exposure routes. Exposure from air emissions can
be minimized by passing the system's air process stream through carbon adsorption units before discharge
to the atmosphere.
4.1.2 Compliance with ARARs
Although general and specific applicable or relevant and appropriate requirements (ARARs) were not
specifically identified for the surfactant-enhanced extraction technology, compliance with chemical-,
location-, and action-specific ARARs should be determined on a site-specific basis. While location- and
action-specific ARARs generally can be met, compliance with chemical-specific ARARs depends on the
efficiency of the surfactant-enhanced extraction system in removing contaminants from the groundwater
and the site-specific cleanup level.
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4.1.3 Long-Term Effectiveness and Permanence
The surfactant-enhanced extraction system permanently removes organic contaminants from the saturated
zone and recovers the surfactant for reuse. Long-term risks to treatment system workers, the community,
and the environment from exposure to contaminated groundwater are mitigated by ensuring that
established standards are met.
The concentrated solution of organic contaminants (the permeate) must be disposed of properly to ensure
the permanence of remediation using this technology. Secondary emissions from the treatment and
disposal of the permeate may present other risks not addressed in this report.
4.1.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
As discussed in Section 4.1.1 and 4.1.3, the surfactant-enhanced extraction technology offers permanent
removal of organic contaminants from the saturated zone. As such, the toxicity, mobility, and volume of
contaminants are also significantly reduced.
4.1.5 Short-Term Effectiveness
The removal of organic contaminants is achieved relatively quickly, providing for short-term
effectiveness as well as long-term effectiveness, as discussed in Section 4.1.3. Potential short-term risks
presented during system operation to workers, the community, and the environment includes air
emissions. Exposure to air emissions during operation, monitoring, and maintenance can be minimized
through the removal of contaminants from the system's air process stream using carbon adsorption units
before emitting this stream to the atmosphere.
4.1.6 Implementability
The surfactant-enhanced extraction technology has been demonstrated at a number of sites in the U.S. and
in Europe. While an innovative technology, sufficient technical information is available to support
application of this technology (Ground Water Remediation Technologies Analysis Center, Technology
Evaluation Report: Surfactants/Cosolvents). The equipment and supply requirements for surfactant
extraction are relatively standard, including wells, pumps, piping, and chemicals (surfactant). Surfactant
separation and recovery processes are more complex, and need to be further proven prior to full-scale
implementation.
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4.1.7 Cost
The cost of surfactant-enhanced extraction has not been fully defined due to unresolved issues related to
recycling the surfactant. However, currently available information suggest that the cost will be relatively
high in comparison to other technologies. Thus, surfactant enhanced extraction should be reserved for
contaminated sites where other, less expensive treatment technologies cannot accomplish the remediation
goals.
4.1.8 State Acceptance
State acceptance is anticipated because the surfactant-enhanced extraction system uses widely accepted
processes to remove contaminants from the saturated zone, and air emissions can be effectively treated
using carbon adsorption. If remediation is conducted as part of Resource Conservation and Recovery Act
(RCRA) corrective actions, state regulatory agencies will require that permits be obtained before
implementing the system, such as a permit to operate the treatment system and an air emissions permit.
4.1.9 Community Acceptance
The system's size and space requirements, as well as the principles of operation, may raise concern in
nearby communities. However, proper management and operational controls coupled with minimal short-
term risks to the community and the permanent removal of contaminants in situ make this technology
likely to be accepted by the public.
4.2 APPLICABLE WASTES
The surfactant-enhanced extraction technology demonstrated at Stuttgart-Vaihingen, Germany, was
designed to remove xylene from the saturated zone. The developer claims and other demonstration
results suggest that the technology can also remove other non-aqueous phase liquid organic contaminants.
However, the technology's applicability to contaminants other than xylene was not examined as part of
this demonstration.
4.3 LIMITATIONS OF THE TECHNOLOGY
The developer claims that there are no concentration limits on the contamination that can be treated by the
system. However, high concentrations of contaminants may require longer operation of the technology
and multiple extractions to achieve remediation goals.
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5.0 SURFACTANT-ENHANCED EXTRACTION TECHNOLOGY STATUS
According to Tauw Umwelt GmbH Moers, the technology can be used for remediation of contamination
in the saturated zone with both VOCs and semivolatile organic compounds (SVOCs). The surfactant-
enhanced extraction technology has been or is currently being demonstrated at several sites in the U.S.
There are currently no commercially operating systems in the U.S.
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6.0 REFERENCES
American Public Health Association (APHA), American Waterworks Association (AWWA), and Water
Environment Federation (WEF). 1994. Standard Methods for the Examination of Water and
Wastewater. Greenberg, Arnold E., Lenore S. Clesceri, and Andrew D. Eaton, eds. 19th edition.
Washington, B.C.
Evans, G. 1990. "Estimating Innovative Technology Costs for the SITE Program." Journal of Air and
Waste Management Assessment. Volume 40, Number 7. July.
Ground Water Remediation Technologies Analysis Center (GWRTAC). Technology Evaluation Report:
Surfactants/Cosolvents.
Tetra Tech EM Inc. (TTEMI) 1998 Quality Assurance Project Plan for the Surfactant-Enhanced
Extraction Technology Evaluation in Stuttgart, Germany. February 4.
U.S. Environmental Protection Agency (EPA). 1983. Methods for Chemical Analysis of Water and
Wastes (MCAWW). Environmental Monitoring and Support Laboratory. Cincinnati, Ohio. EPA-
600/4-79-020. March
EPA. 1988. "Guidance for Conducting Remedial Investigations and Feasibility Studies under
CERCLA." EPA/540/G-89/004. October.
EPA. 1996. "Test Methods for Evaluating Solid Waste." Volumes 1A through 1C. SW-846. Third
Edition. Update III. Office of Solid Waste and Emergency Response (OSWER). Washington, DC.
December.
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