&EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/R-96/502
September 1998
General Environmental
Corporation
CURE Electrocoagulation
Technology
Innovative Technology
Evaluation Report
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
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EPA/540/R-96/502
September 1998
General Environmental
Corporation
CURE Electrocoagulation
Technology
Innovative Technology Evaluation Report
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Printed on Recycled Paper
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Notice
The information in this document has been funded by the U. S. Environmental Protection Agency (EPA) under Contract No.
68-CS-0037 to Tetra Tech EM Inc. (formerly PRC Environmental Management, Inc.). It has been subjected to the Agency's
peer and administrative reviews and has been approved for publication as an EPA document. Mention of trade names or
commercial products does not constitute an endorsement or recommendation for use.
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Foreword
The U. S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's land, air, and water
resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading
to a compatible balance between human activities and the ability of natural systems to 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 ah- 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 thek clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
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Abstract
The CURE electrocoagulation system was evaluated for removal of low levels of the radionuclides uranium, plutonium, and
americium as well as other contaminants in wastewater. Economic data from the Superfund Innovative Technology
Evaluation (SITE) demonstration are also presented, and the technology is compared to the nine criteria that the U. S.
Environmental Protection Agency (EPA) uses to select remedial alternatives for Superfund sites.
The CURE electrocoagulation technology was developed by General Environmental Corporation, Inc. (GEC), of Denver,
Colorado. The technology induces the coagulation and precipitation of contaminants by a direct-current electrolytic process
followed by settling with or without the addition of coagulation-inducing chemicals. Treated water is discharged from the
system for reuse, disposal, or reinjection. Concentrated contaminants in the form of sludge are placed in drums for disposal
or reclamation.
The CURE technology was demonstrated under the SITE Program at the U.S. Department of Energy's (DOE) Rocky Hats
Environmental Technology Site (formerly the Rocky Flats Plant) near Golden, Colorado. Approximately 4,500 gallons of
wastewater containing low levels of the radionuclides uranium, plutonium, and americium were treated in August and
September 1995. Water from the solar evaporation ponds was used in the demonstration. Six preruns, five optimization runs,
and four demonstration runs were conducted over a 54-day period.
The demonstration runs lasted 5.5 to 6 hours each, operating the CURE system at approximately 3 gallons per minute. Filling
the clarifier took approximately 2.5 hours of this time. Once the clarifier was filled, untreated influent, and effluent from the
clarifier were collected every 20 minutes for 3 hours. Because of the shortened run times, there is uncertainty whether the data
represent long-term operating conditions.
Results indicated that removal efficiencies for the four runs ranged from 32 to 52 percent for uranium, 63 to 99 percent for
plutonium, and 69 to 99 percent for americium. Colorado Water Quality Control Commission (CWQCC) standards were met
for plutonium and americium in some, but not all cases. However, CWQCC standards for uranium were not met. Arsenic and
calcium concentrations were also decreased by an average of 74 and 50 percent, respectively for the two runs for which metals
were measured.
Evaluation of the CURE electrocoagulation technology against the nine criteria used by the EPA in evaluating potential
remediation alternatives indicates that the CURE system provides both long- and short-term protection of the environment,
reduces contaminant mobility and volume, and presents few risks to the community or the environment.
Potential sites for applying this technology include Superfund, DOE, U.S. Department of Defense, and other hazardous waste
sites where water is contaminated with radionuclides or metals. Economic analysis indicates that remediation cost for a 100-
gallon-per-minute CURE system could range from about $0.003 to $0.009 per gallon, depending on the duration of the
remedial action.
iv
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Contents
List of Figures and Tables viii
Acronyms, Abbreviations, and Symbols ix
Conversion Factors xi
Acknowledgments xii
Executive Summary 1
1 Introduction 3
1.1 Background 3
1.2 Brief Description of the SITE Program and Reports 3
1.3 Purpose of the Innovative Technology Evaluation Report 4
1.4 Technology Description 4
1.4.1 Theory of Coagulation ; 5
1.4.2 Theory of Electrocoagulation 5
1.4.3 System Components and Function 6
1.5 Key Contacts 8
2 Technology Applications Analysis 9
2.1 Key Features of the CURE Electrocoagulation Technology 9
2.2 Technology Performance 9
2.2.1 Historical Performance 9
2.2.2 Bench-Scale Study Results 10
2.2.3 SITE Demonstration Results 10
2.3 Evaluation of Technology Against RI/FS Criteria 11
2.4 Factors Influencing Performance 11
2.4.1 Influent Water Chemistry 11
2.4.2 Operating Parameters 11
2.4.3 Maintenance of Equipment 11
2.5 Applicable Wastes , 11
2.6 Site Requirements 11
2.7 Materials Handling Requirements 14
2.8 Personnel Requirements 14
2.9 Potential Community Exposures 14
2.10 Potential Regulatory Requirements 15
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Contents (continued)
2.10.1 Comprehensive Environmental Response, Compensation, and Liability Act 15
2.10.2 Resource Conservation and Recovery Act ;..'..... 17
2.10.3 Safe Drinking Water Act .; 17
2.10.4 Clean Water Act 17
2.10.5 Occupational Safety and Health Administration 18
2.10.6 Radioactive Waste Regulations 18
2.10.7 Mixed Waste Regulations 18
2.11 Availability, Adaptability, and Mobility of Equipment 18
2.12 Limitations of the Technology 19
3 Economic Analysis 20
3.1 Basis of Economic Analysis 20
3.2 Cost Categories 22
3.2.1 Site Preparation Costs 22
3.2.2 Permitting and Regulatory Costs 22
3.2.3 Capital Equipment 23
3.2.4 Startup 23
3.2.5 Demobilization 23
3.2.6 Labor , 23
3.2.7 Consumables and Supplies 24
3.2.8 Utilities 24
3.2.9 Effluent Treatment and Disposal 24
3.2.10 Residual Waste Shipping and Handling 24
3.2.11 Analytical Services 24
3.2.12 Maintenance and Modifications 25
4 Treament Effectiveness 26
4.1 Background 26
4.2 Review of SITE Demonstration 26
4.2.1 Site Preparation 26
4.2.2 Technology Demonstration 26
4.2.3 Site Demobilization 28
4.3 Demonstration Methodology 28
4.3.1 Testing Approach 29
4.3.2 Sampling and Analysis and Measurement Procedures 31
4.3.3 Operational and Sampling Problems and Variations from the Work Plan 31
4.4 Review of Demonstration Results 32
4.4.1 Summary of Results for Optimization Runs 32
vi
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Contents (continued)
4.4.2 Summary of Results for Critical Parameters 33
4.4.3 Summary of Results for Noncritical Parameters 35
4.5 Conclusions 40
5 Technology Status 41
6 References 42
Appendix
A Vendor Claims for the Technology
B Case Studies
vii
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Figures
1-1 CUKE Schematic Diagram 7
4-1 Site Location Map 27
4-2 CURE Schematic Diagram and Sampling Locations 30
Tables
2-1 Evaluation of Nine Criteria Used in the Feasibility Study 12
2-2 Metals and Water Quality Parameters for RFETS Solar Evaporation Pond Water and
Corresponding Treaztment Standards 13
2-3 Federal and State ARARs for the CURE System 16
3-1 Costs Associated with the CURE System 21
4-1 Radionuclide Concentrations in Wastewater 34
4-2 Radionuclide Content in Dewatered Sludge 35
4-3 Metal Content in Dewatered Sludge 36
4-4 Metals Concntration in Wastewater 37
4-5 Field Parameter Measurements 38
4-6 Radionuclide Concentration in TCLP Leachate 39
viii
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Acronyms, Abbreviations, and Symbols
A/B decant water
AEA
ARAR
ATTIC
BOD
C
CDPHE
CERCLA
CERI
CFR
CRE
CWA
CWQCC
DOE
Eh
EPA
GEC
gpm
HSWA
ITER
kWh
LANL
LLRW
Lpm
MCL
mg/kg
mg/L
mS
mS/cm
MS/MSD
Ampere
Water removed from A and B solar pond sludge
Atomic Energy Act
Applicable or relevant and appropriate requirements
Alternative Treatment Technology Information Center
Biological oxygen demand
Degrees Celsius
Colorado Department of Public Health and the Environment
Comprehensive Envkonmental Response, Compensation, and Liability Act
Center for Envkonmental Research Information
Code of Federal Regulations
Contaminant removal efficiency
Clean Water Act
Colorado Water Quality Control Commission
U.S. Department of Energy
Oxidation/reduction potential
U.S. Envkonmental Protection Agency
General Environmental Corporation
Gallons per minute
Hazardous and Solid Waste Amendments
Innovative Technology Evaluation Report
Kilowatt-hour
Los Alamos National Laboratory
Low level radioactive waste
Liters per minute
Maximum contaminant level
Milligrams per kilogram
Milligrams per liter
MilliSiemens
MilliSiemens per centimeter
Matrix spike and matrix spike duplicate
ix
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Acronyms, Abbreviations, and Symbols (continued)
NCP
NPDES
NPL
NRC
NRMRL
O&M
ORD
OSHA
OSWER
PA
pCi/L
POTW
PPE
ppm
PRC
psi
QA/QC
QAPP
RCRA
RFETS
SARA
SDWA
SEP
SITE
SWDA
TCLP
TDS
TER
TOG
TRU
TSS
TTU
lira
pS/cm
V
VISITT
National Oil and Hazardous Substance Pollution Contingency Plan
National Pollutant Discharge Elimination System
National Priorities List
Nuclear Regulatory Commission
National Risk Management Research Laboratory
Operation and maintenance
Office of Research and Development
Occupational Safety and Health Administration
Office of Solid Waste and Emergency Response
Protected area
PicoCuries per liter
Publicly owned treatment works
Personal protective equipment
Parts per million
PRC Environmental Management, Inc.
Pounds per square inch
Quality assurance and quality control
Quality assurance project plan
Resource Conservation and Recovery Act
Rocky Flats Environmental Technology Site
Superfund Amendments and Reauthorization Act
Safe Drinking Water Act
Solar evaporation pond
Superfund Innovative Technology Evaluation
Solid Waste Disposal Act
Toxicity Characteristic Leaching Procedure
Total dissolved solids
Technical Evaluation Report
Total organic carbon
Transuranic
Total suspended solids
Transportable treatment unit
Micrograms per liter
Micrometer (micron)
MicroSiemens per centimeter
Volts
Vendor Information System for Innovative Treatment Technologies
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Conversion Factors
To Convert From
To
Multiply By
Length
Area:
Volume:
inch
foot
mile
square foot
acre
gallon
cubic foot
centimeter
meter .
kilometer
square meter
square meter
liter
cubic meter
2.54
0.305
1.61
0.0929
4,047
3.78
0.0283
Mass:
pound
kilogram
0.454
Energy:
kilowatt-hour megajoule
3.60
Power:
kilowatt
horsepower
1.34
Temperature: ("Fahrenheit - 32) "Celsius
0.556
XI
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Acknowledgments
This report was prepared under the direction of Ms. Annette Gatchett, the U.S. Environmental Protection Agency (EPA)
Supcrfund Innovative Technology Evaluation (SITE) project manager at the National Risk Management Research Laboratory
(NRMRL) in Cincinnati, Ohio. This report was prepared by Dr. Theodore Ball, Mr. Jon Bridges, Ms. Barbara DeAngelis, Mr.
David Harr, Ms. Doreen Hoskins, Ms. Jennifer Jones, and Mr. David Walker of PRC Environmental Management,' Inc.
(PRC). Contributors and reviewers for this report were Ms. Gatchett, Mr. Sam Hayes of EPA, and Mr. Carl Dalrymple of
General Environmental Corporation. The report was formatted by Ms. Melissa Fajt, edited by Mr. Christopher Pytel, and
technically reviewed by Ms. Pauline LeBlanc of PRC.
XII
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Executive Summary
This executive summary of the CURE electrocoagulation
technology discusses its applications, evaluates costs
associated with the system, and describes its effectiveness.
The CURE electrocoagulation technology has been
evaluated under the Superfund Innovative Technology
Evaluation (SITE) program. The SITE program was
developed by the U.S. Environmental Protection Agency
(EPA) to maximize the use of alternative treatment
technologies. To this end, reliable performance and cost
data on innovative technologies are developed during
demonstrations where a technology is used to treat a
specific waste.
After the demonstration, EPA publishes an Innovative
Technology Evaluation Report (ITER) designed to aid
decision makers in evaluating the technology for further
consideration as an applicable cleanup option. This report
includes a review of the technology application, an
economic analysis of treatment costs using the
technology, and the results of the demonstration.
The CURE electrocoagulation technology induces the
coagulation and precipitation of contaminants by a direct-
current electrolytic process followed by flocculent settling
with or without the addition of coagulation-inducing
chemicals. The water is pumped through concentric tubes
made of iron or aluminum that act as electrodes. A direct
current electric field is applied to the electrodes to induce
the electrochemical reactions needed to achieve the
coagulation. Treated water is discharged from the system
for reuse, disposal, or reinjection. Concentrated
contaminants in the form of sludge are placed in drums for
disposal or reclamation.
The CURE electrocoagulation process involves the
following basic steps: (1) contaminated water is pumped
through the CURE electrocoagulation tubes; (2) treated
water is pumped to a clarifier to allow solids to settle out;
(3) clarified water is discharged from the system for reuse,
disposal, or reinjection; (4) solid waste is stored for
disposal or reclamation.
The technology demonstration had two primary objectives:
(1) document 90 percent contaminant removal efficiencies
(CRE) for uranium, plutonium, and americium to the 95
percent confidence level; and (2) determine if CURE
could treat the waste stream to radionuclide contaminant
levels below Colorado Water Quality Control Commission
(CWQCC) standards at the 90 percent confidence level.
In addition, the technology demonstration had several
secondary objectives. These were to (1) evaluate anode
deterioration; (2) demonstrate CREs for arsenic, boron,
cadmium, calcium, lithium, magnesium, total organic
carbon (TOC), total dissolved solids (TDS), and total
suspended solids (TSS) of 90 percent or higher at the 90
percent confidence level; (3) document production of
hydrogen and chlorine gases; (4) determine power
consumption by the CURE electrocoagulation system; (5)
determine optimum system operating parameters for
treatment of the demonstration treatment water; (6)
document selected geochemical parameters (pH, oxidation/
reduction potential [Eh], specific conductivity, and
temperature) that may affect the effectiveness of the
CURE electrocoagulation system; (7) determine uranium,
plutonium, americium, andtoxicity characteristic leaching
procedure (TCLP) metals leachability from the flocculent
by TCLP; and (8) estimate capital and operating costs of
building a single treatment unit to operate at the rate of 100
gallons per minute (gpm).
For the demonstration, approximately 4,500 gallons of
water containing up to 2,933 micrograms per liter ( g/L)
uranium, 33.1 picoCuries per liter (pCi/L) plutonium, and
83.5 pCi/L americium were treated in four test runs. Due
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to operating constraints at the demonstration site, no long-
term evaluation of the treatment system was conducted.
Each run was initiated by running process water through
the CURE system until the clarifier was full (approximately
2.5 hours). Sampling of clarifier effluent was conducted
for 3 hours thereafter. These tests may not be
representative of actual operating conditions.
The CURE technology was evaluated against nine criteria
used for decision making in the Superfund remedy
selection process. This evaluation indicates that the CURE
system can provide short- and long-term protection of
human health and the environment by removing
radionuclide contamination from water and concentrating
it in a solid form.
Operation of the CURE electrocoagulation system must
also comply with several statutory and regulatory
requirements. Among these are the Comprehensive
Environmental Response, Compensation, and Liability
Act (CERCLA), Resource Conservation and Recovery
Act (RCRA), Safe Drinking Water Act (SDWA), Clean
Water Act (CWA), Occupational Safety and Health
Administration (OSHA) requirements, radioactive waste
regulations, and mixed waste regulations. These statutes
and regulations should be considered before use of any
remedial technology.
Using information obtained from the SITE demonstration,
an economic analysis was conducted to examine 12
different cost categories for the CURE system treating
contaminated groundwater at a Superfund site. The
analysis examined three cases in which the system treated
water for 1,5, and 10 years. For all treatment durations, a
100 gpm system was used in the cost calculations. Costs
are summarized below.
Fixed costs for all three scenarios were the same.
Therefore, for the 1-year treatment scenario capital
equipment and site preparation dominate costs. Estimated
costs ranged from $0.003 to $0.009 per gallon of water
treated. These costs are estimates, and actual costs will
vary with site conditions, materials and labop costs, and
treatability of the wastestream.
Based on the SITE demonstration, the following
conclusions may be drawn about the effectiveness of the
CURE technology:
Results of chemical analysis of waters collected dur-
ing the four 3-hour demonstration runs showed that
the CURE system removed 32 to 52 percent of ura-
nium, 63 to 99 percent of plutonium, and 69 to 99
percent of americium from solar evaporation pond
water. However, CWQCC standards could not be
attained reliably for plutonium and americium, and
were not met for uranium.
Solid waste generated by the CURE treatment sys-
tem during this demonstration is resistant to leaching
of the radionuclides uranium, plutonium, and ameri-
cium.
The volume of waste generated is substantially less
than the volume of water treated.
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Section 1
Introduction
This section provides background information about the
Superfund Innovative Technology Evaluation (SITE)
program, discusses the purpose of this innovative
technology evaluation report (ITER), and describes the
CURE electrocoagulation technology. For additional
information about the demonstration site, this technology,
and the SITE program, key contacts are listed at the end of
this section.
1.1 Background
In August and September of 1995, the General
Environmental Corporation (GEC) CURE
electrocoagulation system was evaluated at the Rocky
Flats Environmental Technology Site (RFETS), near
Golden, Colorado. The technology demonstration was
conducted as a cooperative effort between the U.S.
Environmental Protection Agency (EPA) and the U.S.
Department of Energy (DOE) which manages the site.
The CURE system was evaluated as a transportable, trailer
mounted unit that uses a series of concentric iron or
aluminum tubes, a power supply to control the electrical
current across the interior and exterior tube, and a clarifier
to remove floccules formed in the tubes. The
demonstration evaluated the ability of the system to
remove uranium, plutonium, and americium from solar
evaporation pond (SEP) water at RFETS.
1.2 Brief Description of the SITE
Program and Reports
The Superfund Amendments and Reauthorization Act
(SARA) of 1986 mandates that the EPA select, to the
maximum extent practicable, remedial actions at
Superfund sites that create permanent solutions (as
opposed to land-based disposal) for contamination that
affects human health and the environment. In response to
this mandate, the SITE program was established by EPA's
Office of Solid Waste and Emergency Response
(OSWER) and Office of Research and Development
(ORD). The SITE program promotes the development,
demonstration, and use of new or innovative technologies
to clean up Superfund sites across the country.
The SITE program's primary purpose is to maximize the
use of alternatives in cleaning hazardous waste sites by
encouraging the development and demonstration of new,
innovative treatment and monitoring technologies. It
consists of the Demonstration Program, the Emerging
Technology Program, the Monitoring and Measurement
Technologies Program, and the Technology Transfer
Program. These programs are discussed in more detail
below.
The Demonstration Program develops reliable performance
and cost data on innovative treatment technologies so that
potential users may assess the technology's site-specific
applicability. Technologies evaluated are either currently
available or close to being available for remediation of
Superfund sites. SITE demonstrations are conducted on
hazardous waste sites under conditions that closely
simulate full-scale remediation, thus assuring the
usefulness and reliability of information collected. Data
collected are used to assess the performance of the
technology, the potential need for pre- and post-treatment
processing of wastes, potential operating problems, and
the approximate costs. The demonstrations also allow for
evaluation of long-term risks and operating and
maintenance (O&M) costs.
The Emerging Technology Program focuses on successfully
proven, bench-scale technologies which are in an early
stage of development involving pilot- or laboratory-scale
testing. Successful technologies are encouraged to
advance to the Demonstration Program.
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Existing technologies which improve field monitoring and
site characterization are identified in the Monitoring and
Measurement Technologies Program. New technologies
that provide faster, more cost-effective contamination and
site assessment data are supported by this program. The
Monitoring and Measurement Technologies Program also
formulates the protocols and standard operating procedures
for demonstrating methods and equipment.
The Technology Transfer Program disseminates technical
information on innovative technologies in the
Demonstration, Emerging Technology, and Monitoring
and Measurements Technologies Programs through
various activities. These activities increase the awareness
and promote the use of innovative technologies for
assessment and remediation at Superfund sites. The goal
of technology transfer activities is to develop interactive
communication among individuals requiring up-to-date
technical information.
Technologies are selected for the SITE Demonstration
Program through annual requests for proposals. ORD staff
review the proposals, including any unsolicited proposals
that may be submitted throughout the year, to determine
which technologies show the most promise for use at
Superfund sites. Technologies chosen must be at the pilot-
or full-scale stage, must be innovative, and must have
some advantage over existing technologies. Mobile
technologies are of particular interest.
Once EPA has accepted a proposal, cooperative
agreements between EPA and the developer establish
responsibilities for conducting the demonstrations and
evaluating the technology. The developer is responsible
for demonstrating the technology at the selected site and is
expected to pay any costs for transport, operations, and
removal of the equipment. EPA is responsible for project
planning, sampling and analysis, quality assurance and
quality control (QA/QC), preparing reports, disseminating
information, and transporting and disposing of treated
waste materials.
The results of the CURE electrocoagulation technology
demonstration are published in two documents: the SITE
technology capsule and the ITER. The SITE technology
capsule provides relevant information on the technology,
emphasizing key features of the results of the SITE field
demonstration. In addition to the ITER, EPA prepares an
unbound technical evaluation report (TER) for each
demonstration. The TER contains raw analytical and
quality assurance data and other operating information
collected during the demonstration. The TER is prepared
to document the quality of the demonstration data upon
which the ITER is based.
1.3 Purpose of the Innovative
Technology Evaluation Report
The ITER provides information on the CURE
electrocoagulation technology and includes a
comprehensive description of the demonstration and its
results. The ITER is intended for use by EPA remedial
project managers, EPA on-scene coordinators, contractors,
and other decision makers for implementing specific
remedial actions. The ITER is designed to aid decision
makers in evaluating specific technologies for further
consideration as an applicable option in a particular
cleanup operation. This report represents a critical step in
the development and commercialization of a treatment
technology.
To encourage the general use of demonstrated
technologies, EPA provides information regarding the
applicability of each technology to specific sites and
wastes. Therefore, the ITER includes information on cost
and site-specific characteristics. It also discusses
advantages, disadvantages, and limitations of the
technology.
Each SITE demonstration evaluates the performance of a
technology in treating a specific waste. The waste
characteristics of other sites may differ from the
characteristics of the treated waste. Therefore, successful
field demonstration of a technology at one site does not
necessarily ensure that it will be applicable at other sites.
Data from the field demonstration may require
extrapolation for estimating the operating ranges in which
the technology will perform satisfactorily. Only limited
conclusions can be drawn from a single field
demonstration.
1.4 Technology Description
The following sections overview coagulation theory, the
electrocoagulation technology, and the CURE
electrocoagulation system.
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1.4.1 Theory of Coagulation
It has long been known that contaminants are dissolved or
suspended in aqueous solutions due to small, electrostatic
charges at the surface of the molecules or particles. If the
surface charges are similar, the molecules or particles will
repel one another. Competing with this repulsion is van
der Waals' force, a weak intermolecular force that results
in the attraction of molecules to one another. However,
van der Waals' force is very small and decreases rapidly
with increasing distance between particles. If the
repulsion caused by the stronger like charges can be
overcome, the van der Waals' force will cause the particles
to coagulate. The addition of electrolytes which have
bivalent or, more effectively, trivalent cations is the
conventional means for overcoming the repulsive force of
the charges and causing coagulation into particles large
enough to precipitate out of solution (Sawyer and McCarty
1978).
In conventional coagulation and precipitation, a chemical
amendment is added to the contaminated solution. The
amendment is generally alum (aluminum sulfate), lime
(calcium oxide), ferric iron sulfate, or charged synthetic or
natural organic polymers (polyelectrolytes). In each case,
the charged portion of the chemical additive destabilizes
and binds with the oppositely-charged contaminants in
solution, causing them to coagulate and, when of sufficient
mass, to precipitate (Sawyer and McCarty 1978; Barkley
and others 1993). This method of contaminant removal
has the disadvantages of requiring frequent and expensive
chemical additions to the solution; leaving high
concentrations of the anionic components of the additive
in solution; and increasing the volume of sludge formed by
subsequent precipitation of the coagulated contaminant.
Some chemical amendments may form stable hydroxide
compounds. Others may be less resistant to degradation
and may not pass the requirements of the EPA's toxicity
characteristic leaching procedure (TCLP) (SW-846
Method 1311, [EPA 1994]). Failure to pass the TCLP will
result in the sludge being characterized as hazardous
waste, increasing sludge disposal costs, and reducing
disposal options.
1.4.2 Theory of Electrocoagulation
In electrocoagulation, alternating or direct current
electricity is applied to a cathode-anode system in order to
destabilize any dissolved ionic or electrostatically
suspended contaminants. During the electrolytic process,
cationic species frtirn the anode metal dissolve into the
water (Equation 1). These cations react with the
destabilized contaminants creating metal oxides and
hydroxides which precipitate. If aluminum anodes are
used, aluminum oxides and hydroxides form; if iron
anodes are used, iron oxides and hydroxides form. The
formation of the oxides and hydroxidess and their
subsequent precipitation, are similar to the processes
which occur during coagulation (or flocculation) and
precipitation using alum or other chemical coagulants.
The differences are the source of the coagulant (in
electrocoagulation it is the cations produced by
electrolytic dissolution of the anode metal [Barkley and
others 1993]), and the activation energy applied promotes
the formation of oxides (Renk 1989). The oxides are more
stable than the hydroxides, and thus, more resistant to
breakdown by acids (Renk 1989). Oxygen gas is also
produced at the anode by the electrolysis of water
molecules (Equation 2), and chlorine gas can be produced
from chloride ions if they are present in the solution to be
treated (Equation 3).
During the electrolytic production of cations, simultaneous
reactions takes place at the cathode producing hydrogen
gas from water molecules (Equation 4). Other important
cathodic reactions include reduction of dissolved metal
cations to the elemental state (Equation 5). These metals
plate on to the cathode. The chemical reactions taking
place during electrocoagulation using iron anodes are
shown below (Vik and others 1984; Jenke and Diebold
1984; Renk 1989; Barkley and others 1993; Hydrologies,
Inc. 1993).
At the anode:
Fe(s) - Fe3+(aq)
(1)
(2)
2Cl-(aq) - C12(g) + 2e-
At the cathode:
2H2O + 2e- -» H2(g) + 2OH-
»M(s)
(3)
(4)
(5)
Where:
Cl'(aq) = Chloride ion in aqueous solution
Cl2(g) = Chlorine gas
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Fc{s) =» Iron solid
Fe*3(aq)= Ferric ions in aqueous solution
H'(aq) = Hydrogen ion in aqueous solution
H2(g) = Hydrogen gas
H,O = Water
MfN*(aq)= Metal ion in aqueous solution
M(s) = Metal solid
OH'(aq)= Hydroxide ion in aqueous solution
O2(g) = Oxygen gas
e~ = Electron
N* = Charge of metal ion
In solution, the ferric ions supplied by dissolution of the
anode participate in further spontaneous reactions to form
oxides and hydroxides (Drever 1988; Renk 1989; Barkley
and others 1993; Hydrologies, Inc. 1993). Renk (1989)
found that oxides preferentially formed in
electrocoagulation experiments because the energy
supplied by the system exceeded the activation energy for
their formation. These reactions incorporated dissolved
contaminants into the molecular structure forming acid
resistant precipitates. These precipitates are typically
capable of passing the TCLP. This can significantly
reduce solid waste disposal costs. Similar reactions occur
when aluminum anodes are used.
1.4.3 System Components and Function
The CURE electrocoagulation technology is designed to
remove contaminants including dissolved ionic species
such as metals; suspended colloidal materials such as
carbon black or bacteria; and emulsified oily materials
from groundvvater or wastewater. The CURE system
induces coagulation of contaminants by means of a direct-
current electrolytic process. Floccules formed by this
process are allowed to settle in a clarifier. Treated water is
discharged from the clarifier for reuse, disposal, or
reinjection; contaminants are concentrated in floes that are
dewatered and discharged to drums for ultimate disposal
or reclamation.
A schematic diagram of the CURE system is shown in
Figure l-l. The major components of the system include
the following:
Influent Storage Tank. This tank collects influent
to be processed by the CURE system in batch mode
or to provide surge capacity during continuous op-
eration.
Influent pH Adjustment Tank. The influent pH can
be adjusted in these tanks if required to bring the in-
fluent pH into the range for optimum operation of the
electrocoagulation tubes.
Electrocoagulation Tubes. The electrocoagulation
tubes consist of a tube-shaped anode material that
concentrically surrounds a tube-shaped cathode ma-
terial leaving an annular space between the anode and
cathode. Contaminated water passes through the cen-
ter of the cathode tube, then through the annular space
between the cathode and anode tubes. Several elec-
trocoagulation tubes may be used in series.
Clarifier. The clarifier is designed to allow floccules
(floes) to continue to form in the treated water and to
settle. Treated water exits the clarifier as the over-
flow. The settled floes form a sludge that is removed
in the underflow.
Bag Filter. Heavy duty polypropylene bag filters are
used to remove sludge from the underflow. Spent
bag filters and sludge are periodically removed for
disposal. Filtrate from the bag filters is recycled
through the electrocoagulation tubes.
Transfer Pumps. Transfer pumps are used to pump
water from the system influent storage tank through
the electrocoagulation tubes to the clarifier. Over-
flow from the clarifier is pumped from a lift station
to discharge. Sludge is pumped from the bottom of
the clarifier through the bag filter.
Several operating parameters can be varied on the CURE
treatment system. These are:
Length of electrocoagulation tubes
Spacing between the inner and outer tubes
Number of electrocoagulation tubes
Tube material, either iron or aluminum
Treatment sequence
Number of passes through each
electrocoagulation tube
-------
Entering
1 Influent
2 NaOH for pH Adjustment
5 Iron from Anodes
Leaving
3 Dewatered Sludge and bag RIters
4 Treated Water
Incoming
Water
Dewatered
Sludge
Legend
»- Flow Direction
Screen
Pump
Bag Filter
Tank
Cure Tubes
Figure 1-1. CURE schematic diagram.
-------
Flow rate and associated residence time for water in
the electrocoagulation tubes and clarifier
Amperage and accompanying voltage
1.5 Key Contacts
Additional information on the RFETS, the CURE
technology, and the SITE program can be obtained from
the following sources:
Rocky Flats Environmental Technology Site
Michael Konczal
Community Relations
U.S. DOE Rocky Flats Field Office
Rocky Flats Environmental Technology Site
P.O. Box 928
Golden, CO 80402-0928
303-966-5993
Jill Paukert
Community Relations
Kaiser-Hill Company, L.L.C.
P.O. Box 464
Golden, CO 80402-0464
303-966-6160
FAX: 303-966-4255
CURE Technology
General Environmental Corporation
c/o Daniel Eide
CURE International, Inc.
1001 U.S. Highway One, Suite 409
Jupiter, FL 33477
516-575-3500
FAX: 516-575-9510
SITE Program
Robert A. Olexsey
Director, Superfund Technology
Demonstration Division
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7861
FAX: 513-569-7620
Annette Gatchett
EPA SITE Project Manager
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7697
FAX: 513-569-7620
Information on the SITE program is available through the
following on-line information clearinghouses:
The Alternative Treatment Technology Information
Center (ATTIC) System is a comprehensive, auto-
mated information retrieval system that integrates data
on hazardous waste treatment technologies into a cen-
tralized, searchable source. This database provides
summarized information on innovative treatment
technologies. Information is available on-line at
www. epa.gov/attic/attic. html.
The Vendor Information System for Innovative Treat-
ment Technologies (VISITT) (Hotline: 800-245-4505)
database contains information on 154 technologies
offered by 97 developers.
The OSWER CLU-In electronic bulletin board con-
tain information on the status of SITE technology
demonstrations. The system operator can be reached
at 301-585-8368.
Technical reports may be obtained by contacting the
Center for Environmental Research Information (CERI),
26 W. Martin Luther King Drive in Cincinnati, OH 45268
or by calling 800-490-9198,
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Section 2
Technology Application Analysis
This section of the ITER evaluates the general
applicability of the CURE system to contaminated waste
sites based on the SITE demonstration results. A detailed
discussion of the demonstration results is presented in
Section 4 of this report. In addition, the developer's claims
regarding the applicability and performance of the CURE
system appear in Appendix A and several case studies
provided by the developer appear in Appendix B.
2.1 Key Features of the CURE
Electrocoagulation Technology
According to the vendor, the CURE system is an ex situ
technology that allows on-site treatment of contaminated
surface or groundwater with limited site preparation. The
technology is unique in that it can remove radionuclides
and metals from Water without the addition of chemicals.
Operation of the CURE technology utilizes electricity to
liberate ferric iron ions from the electrocoagulation tubes
as the contaminated water passes through the tubes. The
ferric ions combine with dissolved or colloidal
contaminants in the water forming floes which are
removed in a clarifier. Use of the CURE system can
substantially reduce the volume of contaminated media
from the volume of contaminated water to the volume of
the dewatered floes. In addition, the mobility of the waste
is reduced. The developer claims that the resulting fioc
can pass the EPA's TCLP.
2.2 Technology Performance
According to the technology developer, electrocoagulation
systems have been used to treat wastewaters for over 85
years (Dalrymple 1994). The CURE electrocoagulation
differs from those previously used by using concentric
pipes as electrodes. This section summarizes the CURE
electrocoagulation technology.
2.2.1 Historical Performance
Electrocoagulation technology using concentric tubes has
been demonstrated as an effective process for the removal
of metals from properly conditioned electroplating
wastewaters. Removal levels appear to be better than
those achieved by conventional hydroxide or carbonate
precipitation using caustic soda, soda ash, or lime. Also,
according to the developer, the metals can be precipitated
at a lower pH as compared to these other commonly used
methods (Dalrymple 1994).
Dalrymple (1994) reports that treatment of electroplating
waste by electrocoagulation using concentric tubes in
conjunction with pH adjustment reduced concentrations
of cadmium, chromium, nickel, and zinc by 99.5 percent
or more for all four metals. These results were compared
with treatment of the same waste stream by pH adjustment
only. Electrocoagulation treatment was 48 percent more
effective than pH adjustment alone for cadmium, and 99.5
percent better for nickel. Chromium removals were
similar for both tests, and zinc removal was 85 percent
higher for pH adjustment alone.
A cadmium plating waste solution was also treated using
the concentric tube electrocoagulation. The cadmium
concentration was decreased by 99.5 percent from 12.0
milligrams per liter (mg/L) to 0.057 mg/L, the copper
concentration was decreased by 96.4 percent from 8,94
mg/L to 0.32 mg/L, the zinc concentration decreased by
86.8 percent from 3.02 mg/L to 0.40 mg/L, and the silicon
concentration decreased by 91.1 percent from 4.49 mg/L
to 0.40 mg/L (Dalrymple 1994).
A truck manufacturing plant installed a concentric tube
electrocoagulation system that reduces the chromium
concentration in their discharge water from 400 mg/L to
0.17 mg/L (99.9 percent removal). The treated water
-------
complies with their discharge requirement of 1.0 mg/L
(Dalrymple 1994).
Treatment of waste streams from acid mine drainage, can
manufacturing, foundries, city sewage, rendering facilities,
food processing, and synthetic fuel manufacturing has also
been tested with concentric tube electrocoagulation.
Metals concentration reductions for metals have ranged
from 31 percent for a river water containing 12.0 mg/L
magnesium to 99.9 percent for zinc and chromium in
electroplating wastewater containing 221 mg/L zinc and
169 mg/L chromium. Dissolved anion concentration
reductions have ranged from 33 percent for sulfate in an oil
brine to 99 percent for phosphate in city sewage. In
addition, biochemical oxygen demand (BOD), oil and
grease concentration, total organic carbon (TOC), and
total suspended solids (TSS) were reduced by 32 to 99
percent (Dalrymple 1994).
2.2.2 Bench-Scale Study Results
A trcatability study was conducted for the CURE
electrocoagulation technology prior to the SITE
demonstration (EPA 1995a). In addition, RFETS
conducted tests of the CURE system prior to the tests done
by EPA. Water from the SEPs at RFETS was used for the
tests. The primary objectives of the treatability study were
as follows:
Evaluate the effectiveness of the CURE technology
for removing uranium, plutonium, and americium to
meet Colorado Water Quality Control Commission
(CWQCC) standards
Determine removal efficiencies for boron, calcium,
magnesium, the inductively coupled plasma metals
suite, nitrate, nitrite, total dissolved solids (TDS), TSS,
and TOC
Evaluate the sludge produced by the CURE technol-
ogy for leachability using the TCLP
Results of the treatability study indicate that the CURE
treatment system is capable of consistently reducing
radionuclide concentration by more than 90 percent, and
CWQCC standards were met for radionuclides in all tests
conducted. Only three other metals (cadmium, chromium,
and boron) exceeded CWQCC standards in the test water.
Cadmium and chromium concentrations were consistently
reduced to below the CWQCC standard, but boron
removal was insignificant. Manganese and molybdenum
concentrations remained the same or increased slightly.
Iron and aluminum concentrations increased during some
of the tests due to dissolution of the anode material. This
may indicate that the applied potential (voltage) was
higher than necessary for effective coagulation, resulting
in excess dissolution of the anodes.
Results of the TCLP analysis of the dewatered sludge
produced by the CURE technology indicate that the metals
barium, cadmium, chromium, selenium, and silver
concentrations in the resultant leachate from the solids
were all below regulatory limits. Sludge production was
estimated to be approximately 2.5 cubic centimeters per
liter of influent.
2.2.3 SITE Demonstration Results
The primary objectives of the CURE technology
demonstration were to determine contaminant removal
efficiencies (CREs) for the radionuclides uranium,
plutomum-23 9/240, and americium-241; and determine if
CWQCC standards for these contaminants could be met
with 90 percent confidence. The mean CREs were
calculated for each of four runs which were conducted
after five optimization runs had been completed. The CRE
for uranium ranged from 32 to 52 percent; the CRE for
plutonium-239/240 was 63 to 99 percent; and the CRE for
americium-241 was 69 to 99 percent.
The CWQCC discharge standards are 15 micrograms per
liter ( g/L) for uranium, 0.05 picoCuries per liter (pCi/L)
for plutonium-23 8/239, and 0.05 pCi/L for americium-
241. The CWQCC standard for uranium was not met
during the demonstration. Some of the tests achieved the
CWQCC standard for plutonium-239/240, but not all, and
the CWQCC standard was met for americium-241 in one
test only.
The CRE for arsenic was determined to be 78.5 percent,
and at 0.02 mg/L, the effluent arsenic concentration was
below the CWQCC standard of 0.05 mg/L. The results for
aluminum and cadmium were inconclusive because their
concentrations were below the detection limit in both the
influent and the effluent. Boron, lithium, magnesium,
TOC, and TDS showed little or no removal. TSS and iron
concentrations increased due to the formation of flocculent
from the dissolving anodes.
The results of the optimization portion of the
demonstration indicated that three electrocoagulation
10
-------
tubes with an annular space of 0.1 to 0.5 inches should be
used. Each tube was 10-feet long, and the water was
pumped through the system at 3.0 to 3.1 gallons per minute
(gpm). One pass through the system is all that was
required. The current was set at 150 amperes, and the
resulting potential was 20 to 57 volts.
2.3 Evaluation of Technology Against
RI/FS Criteria
The CURE technology's applicability was also evaluated
based on the nine criteria used for decision making in the
Superfund feasibility study process. Results of the
evaluation are summarized in Table 2-1.
2.4 Factors Influencing Performance
Three factors affect the performance of the CURE
electrocoagulation technology. These are (1) influent
water chemistry, (2) operating parameters; and (3)
maintenance of the equipment. The following sections
discuss these factors.
2.4.1 Influent Water Chemistry
The CURE electrocoagulation technology can treat a wide
variety of wastewaters to remove dissolved and suspended
contaminants. The chemistry of the wastewater, including
the pH, the oxidation/reduction potential (Eh), dissolved
oxygen, TDS, TSS, and the chemical form of the
contaminants can affect formation of fioccules, thereby
affecting the ability of the technology to remove the
contaminants of interest. Therefore, pretreatment such as
filtering, aeration, or pH adjustment may be necessary. In
addition, the system should be optimized to the influent
characteristics and the contaminants to be removed.
The SEP water used to demonstrate the CURE
electrocoagulation technology contained high levels of
alkalinity, bicarbonate, carbonate, chloride and total
dissolved solids, as shown in Table 2-2. CWQCC and
EPA standards are provided for reference.
2.4.2 Operating Parameters
Use of the CURE technology is waste-specific with
several of the operating parameters requiring optimization
for the specific waste stream to be treated. Adjustable
CURE system operating parameters include:
Tube length
Annular space between the concentric tubes
Number of tubes
Tube material
Sequence of tube materials
Number of passes through the system
Flow rate (residence time)
Applied potential that controls the electricalcurrent
2.4.3 Maintenance of Equipment
Routine maintenance of the CURE electrocoagulation
equipment is required for smooth operation. Maintenance
frequency depends on the electrical current applied and the
sizes of the tubes used. The electrocoagulation tubes must
be cleaned periodically to prevent clogging by solids.
Cleaning is accomplished by flushing the system with
clean water. After flushing is complete, the tubes may be
disassembled and inspected for corrosion. Periodic
replacement of the tubes will be required due to
deterioration from the electrocoagulation process. Filter
bags used for dewatering floes also require periodic
replacement.
2.5 Applicable Wastes
According to the developer of the CURE electrocoagulation
technology, the technology can be applied to many
contaminants dissolved and suspended in water including
metals, uranium, radium, selenium, phosphates, bacteria,
oils, clays, dyes, carbon black, silica, as well as hardness
(calcium carbonate). Waste streams that the developer
claims can be effectively treated by the technology are:
Plating plant effluent
Landfill leachates
Petrochemical waste
Bilgewater
Mine process and wastewater
2.6 Site Requirements
The main requirement of the trailer-mounted CURE
electrocoagulation system is electricity to operate the
electrocoagulation tubes and the pumps that bring water
into and out of the system. The maximum power required
for the electrocoagulation system as demonstrated is 48
amperes at 480 volts, 3 phase or 96 amperes at 240 volts, 3
phase. . The system distributes the power to the power
11
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Table 2-1. Evaluation of CURE Process Based on Nine Criteria of Superfund Feasability Study Process
Criteria
Evaluation
1. Overall protection of
Human. Health and the
Environment
2. Compliance with Federal
Applicable or Relevant and
Appropriate Requirements
(ARARs)
3. Long-Term Effectiveness
and Permanence
4. Reduction of Toxicity,
Mobility, or Volume
Through Treatment
5. Short-Term Effectiveness
6. Implementability
7. Cost
8. Community Acceptance
9. State Acceptance
The CURE technology is capable of removing heavy metal
contaminants from groundwater and therefore prevents further
migration of those contaminants.
Compliance with chemical-, location-, and action-specific ARARs
must be determined on a site-specific basis.
In waste streams with trace levels of contaminants, a high
percentage of the contaminants are permanently removed.
Involves some residuals treatment; (sludge, wastewater) or
disposal. Treatment is a well documented process.
Significantly reduces toxicity, mobility, and volume of
contaminants through treatment. Volume of technology residuals
is small compared to the treated water volume.
Presents few short-term risks to workers and community. Some
personal protective equipment is required to be worn by workers.
Technology involves rapid reduction of contaminants hi the waste
stream.
Involves few administrative difficulties. Utility requirements are
water and electricity. Access for a 1-ton trailer is required and a
2,000 square feet flat area is required.
Costs range from $0.009 per treated gallon for a one year
operation to $0.003 per treated gallon for a ten year operation.
Minimal short-term risks presented to the community make this
technology favorable to the public.
State regulatory agencies may require permits.
12
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Table 2-2. Metals and Water Quality Parameters for RFETS Solar Evaporation Pond Water and Corresponding
Treatment Standards
Metal
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lithium
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
Alkalinity
Total
Bicarbonate
Carbonate
Hydroxide
Nitrate
Nitrate plus
Nitrite
Nitrite
TDS
TOC
TSS
PH
Units
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L (CaCO3)
mg/L (HCCV)
mg/L (C03=)
mg/L (Off)
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
pH units
Tank 029'
<0.10
<0.05
<0.05
< 0.005
1.9
0.011
7.1
0.014
0.006
0.10
0.09
2.1
130
0.015
0.070
0.04
550
<0.05
0.006
2400
<0.5
0.009
0.073
5900
5700
730
<5
<0.05
<0.05
<0.05
8200
440
130
9.1
Tank 031"
<0.10
<0.05
0.21d
0.08
<0.005
2.0
0.057
35
0.087
0.013
0.23
1.4
2.3
140
0.064
0.10
0.06
560
<0.05
0.012
2600
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Table 2-2. Metals and Water Quality Parameters for RFETS Solar Evaporation Pond Water and Corresponding
Treatment Standards (continued)
Notes:
No standard exists
mg/L -Milligrams per liter
* Concentration, based on data collected during the CURE treatability study, April 1995 (EPA 1995a).
b Standards adopted through the Rocky Flats Interagency Agreement - the effluent treatment standard
governing the demonstration (EPA 1991. Federal Facility Agreement and Consent Order. Denver,
Colorado. January).
c Code of Federal Regulations, Title 40 (40CFR) Part 264.94 Resource Conservation and Recovery
Act Subpart F Maximum Contaminant Levels (MCL).
d Concentration based on data collected from the solar evaporation ponds in 1991 (EG&G Rocky Flats
1991. Pond Sludge and Clarifier Sludge Waste Characterization Report).
e Secondary Maximum Contaminant Levels.
supply for the electrocoagulation tubes and the pump, and
reduces it to supply the instrumentation and air
compressor at 120 volts. The compressor is used to supply
air to a diaphragm pump which is used to move the floes
through the bag filter.
An area of approximately 2,000 square feet is required for
setup of the CURE system, and includes space for influent
and effluent storage tanks. The area should be relatively
flat and should be paved or gravel covered. Site access
requirements for the CURE system are minimal. The site
must be accessible to a one-half ton pickup truck pulling a
trailer. The roadbed must be able to support such a vehicle
and trailer delivering the system.
2.7 Materials Handling Requirements
The waste stream is delivered to the CURE
electrocoagulation system using a pump and either piping
or hose. In cases where the distance from the waste source
to the treatment system exceeds 100 feet, additional
pumps may be required to maintain a sufficient delivery
rate. After treatment, effluent water may be recirculated
through the CURE system, stored for further treatment by
another method, discharged directly to another treatment
system, or discharged as treated wastewater in an
approved manner if treatment is sufficient to meet permit
requirements.
Dewatered sludge and filter bags must be stored until
disposal. Storage in 55-gallon drums is common practice.
These drums can be easily handled with a fork lift
equipped with a drum attachment. In most cases the solid
waste generated by the CURE electrocoagulation system
meets nonhazardous classification. However, confirmation
may be required prior to disposal as such.
2.8 Personnel Requirements
Two persons are required for the CURE electrocoagulation
system operation. The pumps and electrode potentials are
controlled by the system operator while the maintenance
technician monitors the system for leaks and treatment
effectiveness. Both personnel are required for routine
maintenance procedures such as cleaning the tubes and
replacing filter bags.
2.9 Potential Community Exposures
The CURE electrocoagulation may produce chlorine,
oxygen, and hydrogen gases that may be released to the
atmosphere. However, operations during both the
treatability study and the demonstration did not produce
detectible levels of hydrogen or chlorine emissions. It is
assumed that these gases were primarily dissolved in the
effluent and their release to the atmosphere was slow.
Oxygen emissions were not measured, but dissolved
oxygen measurements in the effluent indicate that the
14
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oxygen produced from hydrolysis is used up in the
coagulation reactions. Hydrogen and chlorine emissions
from the effluent water are not expected to be hazardous to
the general public or site personnel under open air
conditions.
Solid wastes typically pass TCLP requirements for
disposal as nonhazardous waste. Therefore, the solid
waste generated by the CURE electrocoagulation system
does not generally present an exposure problem to site
personnel or the community. Treatment of wastewaters
containing uranium, plutonium, and americium could
produce low-level radioactive waste sludge. The sludge
will be wet and contained, and will not present a dust
hazard. Potential community exposure to radioactive solid
waste is minimal.
The most significant exposure would be through a rupture
in the system. Containment of such a spill is achieved by
conducting the treatment operations in a lined bermed
area. Should a rupture occur, the pumps can be turned off,
and the system can be shut down immediately. These
precautions will mitigate any potential community
exposure due to system failure.
2.10 Potential Regulatory Requirements
Under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), as amended
by SARA, remedial actions taken at Superfund sites must
comply with federal and state environmental laws that are
determined to be applicable or relevant and appropriate
requirements (ARARs). This section discusses specific
environmental regulations that will most likely be
pertinent to operation of the CURE system, including the
transport, treatment, storage, and disposal of wastes and
treated residuals, and analyzes these regulations in view of
the demonstration results. Regulatory requirements must
be addressed by remedial managers on a site specific basis.
Table 2-3 presents ARARs as they relate to the process
activities conducted during the demonstration.
2.10.1 Comprehensive Environmental
Response, Compensation, and
Liability Act
CERCLA authorizes the federal government to respond to
releases or potential releases of any hazardous substance
into the environment, as well as to releases of pollutants or
contaminants that may present an imminent or significant
danger to public health and welfare or the environment.
As part of the requirements of CERCLA, EPA has
prepared the National Oil and Hazardous Substance
Pollution Contingency Plan (NCP) for hazardous
substance response. The NCP is codified in Title 40 CFR
Part 300 and delineates the methods and criteria used to
determine the appropriate extent of removal and cleanup
for hazardous waste contamination.
SARA amended CERCLA, directing EPA to do the
following:
Use remedial alternatives that permanently and sig-
nificantly reduce the volume, toxicity, or mobility of
hazardous substances, pollutants, or contaminants
Select remedial actions that protect human health and
the environment, are cost-effective, and involve per-
manent solutions and alternative treatment or resource
recovery technologies to the maximum extent pos-
sible
Avoid off-site transport and disposal of untreated haz-
ardous substances or contaminated materials when
practicable treatment technologies exist (Section
In general, two types of responses are possible under
CERCLA: removals and remedial actions. If necessary,
the CURE technology would be part of a CERCLA
remedial action.
Remedial actions are governed by the SARA amendments
to CERCLA. As stated above, these amendments promote
remedies that permanently reduce the volume, toxicity,
and mobility of hazardous substances, pollutants, or
contaminants.
On-site remedial actions must comply with federal and
more stringent state ARARs. ARARs are determined on a
site-by-site basis and may be waived under six conditions:
(1) the action is an interim measure, and the ARAR will be
met at completion; (2) compliance with the ARAR would
15
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Table 2-3. Federal and State ARARs for the CURE System
Process Activity
ARAR
Description
Basis
Response
Waste
Processing
Storage after
Processing
Waste
Characterization
On-site Disposal
Off-site Disposal
Transportation
for off-site
Disposal
Treated Water
Discharge
RCRA 40 CFR
Part 264. 190 to
Part 264.200 or
state equivalent.
RCRA 40 CFR
Part 264. 190 to
Part 264. 199 or
state equivalent.
RCRA 40 CFR
Part 261
Subparts C & D
or state
equivalent.
RCRA 40 CFR
Part 264.300 to
Part 264.317 or
state equivalent.
RCRA 40 CFR
Part 300.
RCRA 40 CFR
Part 262 or state
equivalent.
SDWA, CWA,
40 CFR Part 440
Standards that apply
to the treatment of
hazardous wastes.
Standards that apply
to the storage of
hazardous wastes hi
drums.
Standards that apply
to waste
characteristics.
Standards that apply
to landfilling
hazardous waste.
Requirements for the
off-site disposal of
wastes from a
Superfund site.
Manifest
requirements and
packaging and
labeling
requirements prior
to transporting.
Standards that apply
to discharge of
treated water
The treatment process
occurs in a series of
pipes.
The treated waste will be
placed hi drums.
Need to determine if
treated material is a
RCRA hazardous waste or
mixed waste.
If left on-site, the treated
waste may still be a
hazardous waste or mixed
waste subject to land
disposal restrictions.
The waste is being
generated from a response
action authorized under
SARA.
The used health and safety
gear must be manifested
and managed as a
hazardous or mixed
waste. An identification
number must be obtained
from EPA.
Wastewater containing
metals and radionuclides
is treated and ultimately
discharged to a stream.
CURE system integrity
must be monitored and
maintained to prevent
leakage or failure; the
system must be
decontaminated when
processing is complete.
The drums will be
maintained in good
condition in a secured
area.
Testing will be
conducted prior to
disposal.
Contact EPA for on-site
hazardous waste
disposal; also, disposal
will be in accordance
with DOE RFETS
requirements.
Wastes must be disposed
of hi an approved
manner consistent with
the waste classification.
Wastes and used PPE
are being stored at
RFETS.
Waters discharged from
the CURE system are
collected for further
treatment at RFETS.
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pose a greater risk to health and the environment than
noncompliance; (3) it is technically impracticable to meet
the ARAR; (4) the standard of performance of an ARAR
can be met by an equivalent method; (5) a state ARAR has
not been consistently applied elsewhere; and (6) ARAR
compliance would not provide a balance between the
protection achieved at a particular site and demands on the
Superfund for other sites. These waiver options apply only
to Superfund actions taken on site, and justification for the
waiver must be clearly demonstrated.
The CURE electrocoagulation technology demonstration
at RFETS met all of the SARA criteria, the system
significantly reduced the volume and mobility of
contaminants. In addition, it provided a cost effective,
permanent solution to the treatment of contaminated water
at the site.
2.10.2 Resource Conservation and
Recovery Act
The Resource Conservation and Recovery Act (RCRA),
an amendment to the Solid Waste Disposal Act (SWDA),
was passed in 1976 to address how to safely dispose of the
large volume of municipal and industrial solid waste
generated annually. RCRA specifically addressed the
identification and management of hazardous wastes. The
Hazardous and Solid Waste Amendments of 1984
(HSWA) greatly expanded the scope and requirements of
RCRA.
The presence of RCRA defined hazardous waste
determines whether RCRA regulations apply to the CURE
technology. RCRA regulations define hazardous wastes
and regulate their transport, treatment, storage, and
disposal. Wastes defined as hazardous under RCRA
include characteristic and listed wastes. Criteria for
identifying characteristic hazardous wastes are included in
40 CFR Part 261 Subpart C. Listed wastes from
nonspecific and specific industrial sources, off-specification
products, spill cleanups, and other industrial sources are
itemized in 40 CFR Part 261 Subpart D.
The CURE electrocoagulation system treated SEP water
collected at RFETS. The SEPs have begun RCRA closure
operations. Although wastes have not been disposed in the
ponds since 1986, the ponds are currently regulated under
RCRA. Water in the SEPs has been declared a RCRA
waste. Therefore, the sludge collected in the bag filters
during the demonstration were RCRA derived-waste and
were treated as such by RFETS personnel.
Requirements for corrective action at RCRA-regulated
facilities are provided in 40 CFR Part 264, Subpart F
(promulgated) and Subpart S (proposed). These subparts
also generally apply to remediation at Superfund sites.
Subparts F and S include requirements for initiating and
conducting RCRA corrective actions, remediating
groundwater, and ensuring that corrective actions comply
with other environmental regulations. Subpart S also
details conditions under which particular RCRA
requirements may be waived for temporary treatment units
operating at corrective action sites.
2.10.3 Safe Drinking Water Act
The Safe Drinking Water Act (SDWA) of 1974,
augmented by the Safe' Drinking Water Amendments of
1986, requires EPA to establish regulations to protect
human health from contaminants in drinking water. The
legislation authorizes national drinking water standards
and a joint federal-state system for ensuring compliance
with these standards.
The National Primary Drinking Water Standards,
maximum contaminant levels (MCLs), are found in 40
CFR Parts 141 through 149. In addition, the CWQCC has
set basin specific discharge standards for the streams that
drain the area of RFETS. Table 2-2 presents MCLs and
CWQCC standards. Water treated by the CURE system
must meet these standards in order to be discharged
directly to the drainage. However, water treated by the
CURE system was returned to a receiving tank for
subsequent treatment at RFETS. Wash water from the
decontamination was collected and stored in a tank before
being collected by RFETS for treatment.
2.10.4 Clean Water Act
The CWA is designed to restore and maintain the
chemical, physical, and biological integrity of the nation's
waters. To reach this goal, effluent limitations of toxic
pollutants from point sources were established. Publicly
owned treatment works (POTW) can accept wastewaters
with toxic pollutants from facilities; however, pretreatment
standards must be met and a discharge permit may be
required. A facility wanting to release water to a navigable
waterway must apply for a permit under the National
Pollutant Discharge Elimination System (NPDES). When
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a NPDES permit is issued, it includes waste discharge
requirements.
Three options are available for the water treated by the
CURE system: off-site disposal at a RCRA treatment
facility; discharge through a sanitary sewer under an
industrial pre-treatment permit; and discharge to the
waterways of the U.S. under a NPDES permit. During the
demonstration, water treated by the CURE system was
stored and treated at RFETS.
2.10.5 Occupational Safety and Health
Administration Requirements
CERCLA remedial actions and RCRA corrective actions
must be performed in accordance with OSHA requirements
detailed in 20 CFR Parts 1900 through 1926, especially
Part 1910.120, which provides for the health and safety of
workers at hazardous waste sites! On-site construction
activities at Superfund or RCRA corrective actions sites
must be performed in accordance with Part 1926 of OSHA,
which provides safety and health regulations for
constructions sites. State OSHA requirements, which may
be significantly stricter than federal standards, must also
be met.
All technicians operating the CURE system must complete
an OSHA training course and must be familiar with all
OSHA requirements relevant to hazardous waste sites. For
most sites, minimum personal protective equipment (PPE)
for technicians includes gloves, hard hats, steel toe boots,
and coveralls. Depending on contaminant types and
concentrations, additional PPE may be required. The
CURE system and support equipment was mounted and
operated on the bed of a trailer truck. All equipment on the
system meets OSHA requirements for safety of operation.
2.10.6 Radioactive Waste Regulations
The CURE electrocoagulation technology may be used to
treat water contaminated with radioactive elements. The
primary agencies that regulate the cleanup of radioactively
contaminated sites are EPA, the Nuclear Regulatory
Commission (NRC), the DOE, and the states.
The SDWA has established MCLs for alpha- and beta-
emitting radionuclides which may be appropriate in setting
cleanup standards for radioactively contaminated water.
Discharge of treated effluent from the CURE
electrocoagulation system could also be subject to
radionuclide concentration limits established in 40 CFR
Part 440 (Effluent Guidelines for Ore Mining and
Dressing). These regulations include effluent limits for
facilities that extract and process uranium, radium, and
vanadium ores. In addition, several states have set more
stringent standards for surface waters discharged from
nuclear facilities within their jurisdiction.
NRC regulations cover by licenses the possession and use
of source, by-product, and special nuclear materials.
These regulations apply to sites where radioactive
contamination exists and cover protection of workers and
public from radiation, discharges of radionuclides in air
and water, and waste treatment and disposal requirements
for radioactive waste. In evaluating requirements for
treating radiologically contaminated waters, consideration
must be given to the quality of the raw water, the final
effluent, and any process residuals, specifically the
dewatered floes. If the CURE technology is effective for
radionuclides, these radioactive contaminants will be
concentrated in the dewatered floes. This could affect
disposal requirements, as well as health and safety
considerations.
DOE requirements are included in a series of internal DOE
orders that have the same force as regulations at DOE
facilities. DOE orders address exposure limits for the
public, concentration or residual radioactivity in soil and
water, and management of radioactive wastes.
2.10.7 Mixed Waste Regulations
Use of the CURE electrocoagulation technology at sites
with radioactive contamination may involve the treatment
or generation of mixed waste. As defined by Atomic
Energy Act (AEA) and RCRA, mixed waste contains both
radioactive and hazardous components and is subject to
both acts. When the application of both regulations results
in a situation inconsistent with the AEA, AEA
requirements supersede RCRA requirements.
EPA's Office of Solid Waste and Emergency Response
(OSWER), in conjunction with the NRC, has issued
several directives to assist in the identification, treatment,
and disposal of low-level radioactive mixed waste. If
high-level mixed waste or transuranic mixed waste is
treated, DOE internal orders should be considered when
developing a protective remedy.
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2.11 Availability, Adaptability, and
Mobility of Equipment
The system used for the demonstration is mounted on a 18-
foot long by 6 "-foot wide trailer. This system can easily be
transported to a site for operation. The trailer has a process
pump, four CURE electrocoagulation tubes of different
materials, control panel, power supply, air compressor, a
small clarifier, and a bag filter for dewatering sludge.
The throughput of this system is adjustable as there is a
variable frequency drive on the process pump. The flow
can be set from 0.5 to 5 gpm. The clarifier is a simple
design that utilizes the settled floe as a filtering system.
The retention time in the clarifier is 2.3 hours at a flow rate
of 1 gpm. The retention time required depends on the
characteristic of the floe.
The trailer process pump can pump up to 5 gpm
effectively. The retention time of the clarifier may not be
long enough at this high flow rate. If higher flow rates are
required, the clarifier may be modified or a larger clarifier
may be used. The trailer unit was built as a test and
demonstration unit and is available for use on short notice.
As an alternate to the demonstration trailer unit, GEC is
manufacturing a larger transportable system. This system
is called a Transportable Treatment Unit (TTU). The TTU
trailer is 42 feet long and 8 ° feet wide and is pulled by a
semitractor. The TTU is self-contained, requiring only
diesel fuel to operate the generator. The throughput is up
to 50 gpm. The TTU contains a clarifier and filter press for
dewatering the sludge.
2.12 Limitations of the Technology
Electrocoagulation does not tend to remove inorganic
contaminants that do not form precipitates, such as sodium
and potassium. If a contaminant does not tend to form a
precipitate or sorb to solids, electrocoagulation will not be
a reliable treatment method. Although certain large
organic compounds can be removed such as tannins and
dyes, electrocoagulation is not effective in removing light-
weight organic materials, such as ethanol, methylene
chloride, benzene, toluene, or gasoline.
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Section 3
Economic Analysis
This section presents cost estimates for using the CURE
technology to treat groundwater. Three cases are
presented based on treatment time. These cases are based
on 1-year, 5-year, and 10-year treatment scenarios. The
CURE technology can be operated at several different
flow rates, but 100 gpm was assumed for this economic
analysis because groundwater is typically treated in large
quantities.
Cost estimates presented in this section are based primarily
on data compiled during the SITE bench-scale study and
field-scale demonstration at RFETS. Costs have been
assigned to 12 categories applicable to typical cleanup
activities at Superfund and RCRA sites (Evans 1990).
Costs are presented in November 1995 dollars and are
considered estimates. This economic analysis is designed
to conform with the specifications for an order-magnitude
estimate. This level of precision was established by the
American Association of Cost Engineers for estimates
having an expected accuracy within +50 percent and -30
percent. In this definition, these estimates are generated
without detailed engineering data.
Table 3-1 breaks down costs for the 12 categories for all
throe cases. The table also presents total one-time costs
and annual O&M costs; the total costs for a hypothetical,
long-term groundwater remediation project; and the costs
per gallon of water treated.
3.1 Basis of Economic Analysis
A number of factors affect the estimated costs of treating
groundwater with the CURE system. Factors affecting
costs generally include flow rate, type and concentration of
contaminants, groundwater chemistry, physical site
conditions, geographical site location, availability of
utilities, and treatment goals. Ultimately, the characteristics
of residual wastes produced by the CURE system also
affect disposal costs because they determine whether the
residuals require either further treatment or off-site
disposal. GEC claims that the CURE technology can be
used to treat several types of liquid wastes, including
contaminated groundwater and industrial wastewater.
Groundwater containing radionuclides was selected for
this economic analysis because radioactive wastewater
was used in this demonstration, and groundwater
remediation involves most of the cost categories. The
following text presents the assumptions and conditions as
they apply to each case.
For each case, this analysis assumes that the CURE system
will treat contaminated groundwater at 100 gpm on a
continuous flow cycle, 24 hours per day, 365 days per year.
Based on this assumption, the CURE system will treat
about 52.6 million gallons of water a 1-year period. Over
a 5-year period, this number will rise to 263 million
gallons, and over 10 years, to 526 million gallons.
This analysis assumes that treated water for each case will
be discharged to surface water, and that specified
discharge levels will be achieved with one pass through the
electrocoagulation tubes.
The following assumptions were also made for each case
in this analysis:
The site is located near an urban area within 500 miles
of Denver, Colorado, the home office of GEC.
Water contamination at the site resulted from mining
or nuclear operations.
Contaminated water is located in an aquifer within
150 feet of the surface.
Access roads exist at the site.
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Table 3-1 . Costs Associated with the CURE System at a Treatment Rate of 1 00 gpm
Scheduled Treatment Time
Cost Categories
Ivear Svears 10 years
Fixed Costs
Site Preparation
Administrative
Bench-scale study
Mobilization
Permitting and Regulatory Compliance
Capital Equipment
Extraction wells, pumps, and piping
Treatment equipment
, Storage tank purchase (2 tanks)
Portable berm purchase
Startup
Demobilization
Decontamination/reconstruction
Salvage value
Variable Costs
Labor
Consumables and supplies
Replacement components
PPE
Disposable drums for PPE
Miscellaneous
Utilities
Water
Electricity
Effluent treatment and disposal
Residual and waste shipping and handling
Solids disposal
PPE disposal
Analytical services
Maintenance and modifications
Total fixed costs
Total variable costs
Total cost per gallon treated
$18,000
$5,000
$353,700
$5,000
($31,000)
$35,000
$12,400
$26,480
$0
$8,100
$27,000
$40,000
$350,700
$138,980
$0.009
$8,000
$7,000
$3,000
$158,000
$181,200
$4,500
$10,000
$5,000
($36,000)
$10,000
$1,300
$100
$1,000
$200
$26,280
$6,700
$1,400
$18,000
$5,000
$353,700
$5,000
($31,000)
$175,000
$62,000
$132,400
$0
$40,500
$135,000
$200,000
$350,700
$609,900
$0.004
$8,000
$7,000
$3,000
$158,000
$181,200
$4,500
$10,000
$5,000
($36,000)
$50,000
$6,500
$500
$5,000
$1,000
$131,400
$33,500
$7,000
$18,000
$5,000
$353,700
$5,000
($31,000)
$350,000
$124,000
$264,000
$0
$81,000
$270,000
$400,000
$350,700
$1,192,800
$0.003
$8,000
$7,000
$3,000
$158,000
$181,200
$4,500
$10,000
$5,000
($36,000)
$100,000
$13,000
$1,000
$10,000
$2,000
$262,800
$67,000
$14,000
Note:
Costs are based on 1995 dollars and are rounded to the nearest $100.
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Utility lines, such as electricity and telephone lines,
exist on site.
Water will be treated at a rate of 100 gpm and will be
stored at the site.
Floe will be treated and then disposed of off site as
low level mixed waste; wash water will be stored and
then disposed of off site.
GEC will sell the CURE system to the site owner.
One treated water sample and one untreated water
sample will be collected and analyzed weekly to
monitor system performance. Analyses will include
gross alpha, uranium, and metals.
One full-time equivalent operator will be required to
operate the equipment, collect all required samples,
and conduct equipment maintenance and minor re-
pairs.
Labor costs associated with major equipment repairs
or replacement are not included.
3.2 Cost Categories
Cost data associated with the CURE technology have been
assigned to one of the following 12 categories: (1) site
preparation; (2) permitting and regulatory requirements;
(3) capital equipment; (4) startup; (5) demobilization; (6)
labor; (7) consumables and supplies; (8) utilities; (9)
effluent treatment and disposal; (10) residual and waste
shipping and handling; (11) analytical services; and (12)
maintenance and modifications.
Costs associated with each category are presented in the
following sections. Each section presents the costs that are
identical for each case. If applicable, differences among
the costs of the three cases are then discussed. Some
sections end with a summary of the significant costs within
the category. All direct costs associated with operating the
CURE system are identified as CURE direct costs; all costs
associated with the hypothetical remediation and auxiliary
equipment are identified as groundwater remediation
costs.
3.2.1 Site Preparation Costs
Site preparation costs include administration, bench-scale
testing, and mobilization. This analysis assumes a total of
about 2,000 square feet will be needed to accommodate the
skid-mounted CURE system, support equipment, and
treated and untreated water storage areas. A solid gravel
(or ground) surface is preferred for any remote treatment
project. Pavement is not necessary, but the surface must be
able to support a portable unit weight of approximately
45,000 pounds during operation. This analysis assumes
adequate surface areas exist at the site and will require
minimal modifications.
A bench-scale test series will be conducted to determine
the appropriate specifications of the CURE system for the
site. Cost of the bench-scale study is estimated at $7,000
for tests which include analytical work and a site visit.
Administrative costs, such as legal searches and access
rights, are estimated to be $8,000.
Mobilization involves transporting the entire CURE
system from Denver, Colorado, delivering all rental
equipment to the site, and connecting utilities to the skid.
For this analysis, the site is assumed to be located within
500 miles of Denver, Colorado, to minimize transportation
costs. In addition, equipment vendors are assumed to be
situated nearby the site. The total estimated mobilization
cost will be approximately $3,000.
For each case, total site preparation costs are estimated to
be $18,000.
3.2.2 Permitting and Regulatory
Requirements
Permitting and regulatory costs vary depending on
whether treatment is performed at a Superfund site or a
RCRA corrective action facility and on the disposal
method selected for treated effluent and any solid wastes
generated. At Superfund sites, remedial actions must be
consistent with ARARs of environmental laws, ordinances,
regulations, and statutes, including federal, state, and local
standards and criteria. In general, ARARs must be
determined on a site-specific basis. RCRA corrective
action facilities require additional monitoring records and
sampling protocols, which can increase permitting and
regulatory costs. For this analysis, total permitting and
regulatory costs are estimated to be $5,000.
22
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3.2.3 Capital Equipment
Capital equipment costs include installing extraction
wells; purchasing and installing the complete CURE
treatment system including a portable air compressor; and
purchasing two storage tanks, one-for treated water and
one for rinse water. Extraction wells were included in the
scenario because they are usually required in pump and
treat groundwater remediation systems.
Extraction well installation costs associated with a
groundwater remediation project include installing the
well and pump connecting the pumps, piping, and valves
from the wells to the CURE system. This analysis assumes
that four 150-foot extraction wells with 4-inch polyvinyl
chloride (PVC) casings will be required to maintain 100
gpm flow rate. Extraction wells can be installed at about
$150 per foot per well. Total well construction costs for
each case will be about $90,000. Alternatively, secondary
wastewater can be inexpensively pumped directly from
holding tanks to the system.
Pumps, piping, and valve connections associated with a
groundwater remediation project will depend on the
following factors: the number and size of extraction wells
needed, the material selected, the flow rate, the distance of
the extraction wells from the treatment system, and the
climate of the area. This analysis assumes that four
extraction wells are located within approximately 200 feet
from the CURE system. Four 25-gpm pumps will be
required to maintain a 100-gpm flow rate, at a total cost of
about $20,000. Schedule 80 PVC piping and valve
connection costs are about $60 per foot, including
underground installation. Therefore, total piping costs
will be an additional $48,000.
The complete CURE treatment system includes a 16-foot
skid equipped with a power supply, electrocoagulation
tubes, a clarifier, a filter press, transfer pumps, and
electrical control panel. The clarifier and filter press are
each on stand-alone skids. The cost of fabricating a skid
mounted CURE system capable of treating flow rates of up
to 100 gpm is approximately $181,200. The system
includes a redundant set of electrocoagulation tubes to
allow for cleaning and maintenance.
A 6,500-gallon high density polyethylene storage tank
should be used to store the treated water for analytical
testing prior to off-site discharge or reuse. An additional
1,000-gallon polyethylene water storage tank, costing
$1,000, will be used; for equipment washdown and
decontamination rinse waters. It is assumed that a 6,500-
gallon tank will be purchased for a cost of $3,500 and a
1,000-gallon tank for $1,000.
One 46- by 64-foot portable containment berm was costed
to provide secondary containment under the CURE system
and storage tanks. It is assumed that the berm will be
purchased for $ 10,000. For this analysis, total capital costs
are estimated at $353,700.
3.2.4 Startup
GEC will provide trained personnel to assemble and
optimize the CURE treatment system. GEC personnel are
assumed to be health and safety trained for the site of
operations. Therefore, training costs are not incurred as a
direct startup cost in this analysis. This analysis assumes
that startup will take two people approximately 40 hours
each to complete and has a total cost of $5,000.
3.2.5 Demobilization
Site demobilization costs include berm cleaning and
equipment decontamination, plus site restoration and
confirmation. Site restoration activities include regrading
or filling excavation areas, and demobilization and
disposal of all fencing. Total demobilization costs are
estimated to be approximately $5,000.
A lifespan of 15 years is assumed for the CURE system
and a salvage value of approximately 20 percent of the
original cost, or $36,000.
3.2.6 Labor
Labor costs include a full-time equivalent technician to
operate and maintain the CURE system. Once the system
is functioning, it is assumed to operate continuously at the
designed flow rate. One technician will monitor the
system and equipment, make any required operational
adjustments, conduct routine sampling, and provide
administrative services associated with system operations.
This analysis assumes a 40-hour work week, 52 weeks per
year, at an hourly rate of $ 16.83. Annual labor cost will be
approximately $35,000.
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3.2.7 Consumables and Supplies
The consumables and supplies associated with CURE
system operations include replacement components for the
CURE system, disposable personal protection equipment
(PPE), drums for disposing used PPE, and miscellaneous
items.
Replacement components include electrocoagulation
tubes, fittings, and other miscellaneous parts on the CURE
system. This analysis assumes an annual cost of these
items of $40,000.
Disposable PPE includes Tyvek coveralls, gloves, and
booties. The treatment system operator will wear PPE
when required by the health and safety plan during system
operation. This analysis assumes the PPE will cost
approximately S25 per day, be required approximately 1
day per week, 52 weeks per year for the duration of the
project. Total annual PPE costs are estimated to be about
$1,300.
Three 55-gallon open-headed, plastic-lined drums are
estimated to be needed for disposing of used disposable
health and safety and sampling gear, as well as for storing
nonhazardous wastes for disposal. Total disposal drum
costs are estimated to be about $100 per year.
Miscellaneous costs of $1,000 were included for the
purchase of miscellaneous small parts and supplies.
3.2.8 Utilities
Utilities used by the CURE system include electricity and
water. The CURE treatment system requires about 200
gallons of potable water per week. This water is used for
cleaning and decontamination of the CURE system and
operators. This analysis estimates water to cost $0.02 per
gallon. Total water costs will be about $4 per week, for a
total of approximately $200 per year. This cost can vary by
as much as 100 percent depending on the geographic
location of the site, availability of water, and distance to
the nearest water main.
Electricity to operate the process equipment, field
laboratory equipment, and air compressor is assumed to be
available at the site. Electricity is assumed to cost $3 per
hour, or about $26,280 per year. This analysis assumes
that electricity costs about $0.06 per kilowatt-hour (kWh).
Electricity costs can vary by as much as 50 percent
depending on the geographical location and local utility
rates. No estimate of kWh per 1,000 gallons of water
treated has been calculated.
3.2.9 Effluent Treatment and Disposal
The analysis assumes that the effluent stream will have a
pH from 7.0 to 8.3, and will not contain regulated
pollutants exceeding EPA and state discharge limits;
hence, no further treatment should be needed. Local
regulations may require discharge to a POTW, which may
result in additional charges to the CURE system operator.
For this analysis, effluent treatment and disposal costs are
estimated at $0 per year.
3.2.10 Residual Waste Shipping
and Handling
This analysis assumes that approximately 50 cubic feet per
year of dewatered floe. Disposal of the floe typically
involves mixing the dewatered floe with a powdered
commercial chemical stabilizing material in 55-gallon
drums. During the SITE demonstration, these drums were
stored at an EPA- and DOE-approved storage facility.
This estimate assumes the drums will be classified as low-
level mixed waste and disposal costs for 14 drums of
stabilized floe are estimated at $6,700.
Drummed PPE will be screened for radioactivity and
disposed of in accordance with state and federal
requirements. This analysis assumes that approximately
two drums per year must be disposed of and will be
classified as low level mixed waste. This analysis
estimates a cost of $1,400 for this disposal.
Decontamination and wash water generated during CURE
system operation are returned to the CURE system for
treatment.
3.2.11 Analytical Services
Analytical costs associated with a groundwater remediation
project include laboratory analyses, data reduction and
tabulation, QA/QC, and reporting. For each case, this
analysis assumes that one sample of untreated water and
one sample of treated water will be analyzed for gross
alpha radioactivity, uranium, and metal concentrations
each week, along with QA samples. Monthly laboratory
24
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analyses are estimated at $1,500; data reduction,
tabulation, QA/QC, and reporting are estimated to cost
about $750 per month. Total annual analytical services
costs for each case are estimated to be about $27,000 per
year.
3.2.12 Maintenance and Modifications
Annual repair and maintenance costs apply to all
equipment involved in every aspect of ground-water
remediation with the CURE treatment system. No
modification costs are assumed to be incurred. Based on
information from GEC, total annual maintenance costs are
estimated to be about $40,000 per year.
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Section 4
Treatment Effectiveness
The following sections describe the CURE
electrocoagulation demonstration that was conducted at
RFETS during August and September 1995. The
demonstration was conducted as a cooperative effort
between the DOE, EPA, and Colorado Department of
Public Health and the Environment (CDPHE).
4.1 Background
RFETS is located in northern Jefferson County, Colorado,
approximately 16 miles northwest of downtown Denver
(Figure 4-1). The 400-acre plant site is located within a
restricted area of approximately 6,550 acres, which serves
as a buffer zone between the plant and surrounding
communities. The immediate area around RFETS is
primarily agricultural or undeveloped land. Population
centers within 12 miles of the facility include the cities of
Boulder, Broomfield, Golden, and Arvada.
RFETS began operations in 1952, and was a key facility in
the federal government's nationwide nuclear weapons
research, development, and production program. The
mission of the plant has now changed from production to
decontamination and decommissioning of facilities,
environmental restoration, and waste management.
The source of water for the demonstration is the RFETS
SEPs. This series of five evaporation ponds is located in
the central portion of the RFETS, inside the protected area
(PA). This series of ponds was initially placed into service
from August 1956 to June 1960. These ponds were used to
store and treat liquid process wastes having less than
100,000 pCi/L of total long-lived alpha activity (DOE
1980). These process wastes also contained high
concentrations of nitrates, and treated acidic wastes,
including sanitary sewer sludge, lithium chloride, lithium
metal, sodium nitrate, ferric chloride, sulfuric acid,
ammonium persulfates, hydrochloric acid, nitric acid,
hexavalent chromium, tritium, and cyanide solutions
(Rockwell 1988).
Placement of process waste material in the SEPs ceased in
1986 due to changes in waste treatment operations. In
1994, the sludge and liquid remaining in the A and B ponds
were removed and placed in storage tanks inside
temporary structures erected on the 750 Pad. Water
decanted from this sludge and liquid (A/B decant water)
was used for the demonstration.
4.2 Review of SITE Demonstration
The SITE demonstration was divided into three phases (1)
site preparation; (2) technology demonstration; and (3)
site demobilization. The following paragraphs discuss
these activities.
4.2.7 Site Preparation
A total of about 5,500 square feet of asphalt paved parking
lot was used to set up the containment berms, portable
generator, waste storage container, and support facilities.
Site preparation required 10 days to complete. Site
preparation consisted of setting up the containment berm
used to contain the CURE system, unloading two 6,500-
gallon tanks used to store effluent, setting up a second
berm to contain the tanker truck delivering the water to be
treated by the system, and setting up the hoses required to
bring the water from the tanker truck to the CURE system
and then to the storage tanks.
4.2.2 Technology Demonstration
Prior to conducting the demonstration, GEC conducted six
preruns and five optimization runs over an 11- day period.
The preruns allowed for testing of the system integrity and
confirmation that all equipment was functioning properly.
26
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U.S. DEPARTMENT
OF ENERGY
ROCKY FLATS
ENVIRONMENTAL
TECHNOLOGY SITE
INDUSTRIALIZED
AREA
ENVIRONMENTAL
TECHNOLOGY
SITE
Figure 4-1. Site location map.
NOT TO SCALE
27
-------
Clean process water was used in all of the preruns. The
optimization runs were used to configure the CURE
electrocoagulation system for optimal removal of
contaminants from the process influent. Parameters that
were adjusted include the annular space between the tubes,
the diameter of the tubes, the number of tubes, the tube
material and the sequence, electrical potential, electrical
current, and flow rate.
Approximately 4,500 gallons of contaminated water were
treated by the CURE system during four demonstration
runs conducted over a 2-week period. The run schedule
was set up to allow alternating days for demonstration runs
and system cleanup due to the operating schedule at
RFETS.
All four runs were conducted using the same operating
parameters. These parameters were set on the basis of the
optimization run results. The demonstration runs were
conducted to assess the ability of the CURE system to
consistently produce treated water meeting the
demonstration goals. Sampling activities were performed
in tvvo phases for each run. Each run was initiated by
running process water through the CURE
electrocoagulation system to the clarifier. The field
parameters specific conductance, pH, dissolved oxygen
and temperature of the effluent from the CURE tubes were
measured every 5 minutes for 30 minutes after pumping
commenced. Filling the 450-gallon clarifier took
approximately 2.5 hours. Once the clarifier was full,
samples of untreated influent, effluent from the clarifier,
and effluent from the clarifier that was filtered through a
40-micron filter were collected every 20 minutes for 3
hours. These samples were analyzed for the radionuclides
uranium, plutonium, and americium. The field parameters
were also measured at the two sample locations at the time
of sample collection. Samples were also collected for total
metals analysis at the two sampling locations in runs 1 and
3. The runs were terminated after the last samples were
collected. Dewatered sludge samples were collected after
each run and analyzed for uranium, plutonium, and
americium. The TCLP was also performed on the sludge.
Sludge samples from runs 1 and 3 were also analyzed for
total metals.
4.2.3 Site Demobilization
Site demobilization activities began after the demonstration
was complete. Demobilization activities included
draining the two 6,500-gallon process water tanks;
disconnecting the portable generator; and decontaminating
and removing the treatment system, the two 6,500-gallon
storage tanks, and the two temporary berms.
The CURE system was decontaminated with high-
pressure steam at the RFETS decontamination pad.
RFETS personnel decontaminated the two 6,500-gallon
storage tanks while they were inside the berm by spraying
the tank interiors with water. This wastewater was
pumped to a tanker truck and taken to Building 374 for
final treatment. Rinsate samples were collected and
analyzed for attainment of the performance standards in
Part VIII of the Rocky Flats RCRA permit. EPA
decontaminated the larger of the two temporary berms
with non-phosphate detergent and water.
The CURE system, the two 6,500-gallon tanks, and the
berm were screened for radioactive contamination by
RFETS personnel. The CURE system and the berm were
released by RFETS personnel after the analytical results
indicated that the decontamination procedures were
successful.
Because RFETS personnel decided that additional
analyses of the tank rinsate wastewater was necessary, the
removal schedule for the tanks and the smaller inflatable
berm was delayed. Both of the tanks and the inflatable
berm, on which the tanks were setting, remained on-site
for three weeks after the demonstration. After the tanks
were picked up by the vendor, the smaller, inflatable berm
was decontaminated with non-phosphate detergent and
water by EPA.
4.3 Demonstration Methodology
The technology demonstration was designed to address
two primary and eight secondary objectives. The primary
objectives were to document 90 percent CREs for
uranium, plutonium, and americium to the 95 percent
confidence level; and to determine if CURE could treat the
waste stream to radionuclide contaminant levels below
CWQCC standards atthe 90 percent confidence level. The
data required to achieve these objectives are called the
critical parameters. They include uranium, plutonium,
and americium concentrations in the influent and effluent.
The secondary objectives were as follows:
Evaluate anode deterioration
28
-------
Demonstrate CREs for arsenic, boron, cadmium, cal-
cium, lithium, magnesium, TOC, TDS, and TSS of
90 percent or higher at the 90 percent confidence level
* Document production of hydrogen and chlorine gas-
ses
Determine power consumption by the CURE elec-
trocoagulation system
Determine optimum system operating parameters for
treatment of A/B decant water
Document selected geochemical parameters (pH, Eh,
specific conductivity, and temperature) that may af-
fect the effectiveness of the CURE electrocoagula-
tion system
Determine uranium, plutonium, americium, and TCLP
metals teachability from the flocculent by TCLP
Estimate capital and operating costs of building a
single treatment unit to operate at the rate of 100 gpm
Secondary objectives provide information that is useful,
but not critical, to the evaluation of the system. Data
required to achieve the secondary objectives are called
noncritical parameters. These parameters include:
Periodic visual inspection of the electrodes and docu-
mentation of their replacement
Influent and effluent concentrations of arsenic, bo-
ron, cadmium, calcium, lithium, magnesium, TOC,
and TSS
Air monitoring results for chlorine and hydrogen gas
at the point where the treated water leaves the elec-
trocoagulation tubes
Documentation of the quantity of fuel used by the
CURE electrocoagulation system and the volume of
water treated
Documentation of the length of the electrocoagula-
tion tubes, the annular space between them, the num-
ber of tubes, the tube material, the number of passes
through the tubes, the flow rate, the electrical cur-
rent, and the applied, potential throughout the dem-
onstration, including the optimization runs
Periodic measurement of pH, Eh or dissolved oxy-
gen, specific conductance, and temperature of both
the influent and effluent
Concentrations of TCLP metals and radionuclides in
the resultant leachate from a TCLP performed on a
sample of the flocculent
Documentation of all costs associated with the dem-
onstration and an estimation of construction costs
4.3.1 Testing Approach
The CURE electrocoagulation demonstration consisted of
six preruns, five optimization runs, and four demonstration
runs. The preruns were conducted using clean process
water to test the fittings, piping, and overall integrity.
The optimization runs were used to determine the best
operating conditions for the system. Parameters such as
the tube material, annular space between the tubes, the
flow rate, and the electrical current were adjusted during
these runs. These parameters were adjusted in response to
observations of the technology developer and the water
quality parameters pH, dissolved oxygen, specific
conductivity, and temperature. Operating parameters
were also adjusted based on results from quick turn around
of gross alpha analysis of treated water samples.
Four demonstration runs were completed to achieve the
primary objectives as stated in Section 4.3. Influent and
effluent water samples were obtained from sampling ports
LI and L2 (Figure 4-2). Sample results of influent and
effluent were compared to evaluate the CRE of the CURE
system. During each 3-hour test run, composite samples of
influent and effluent were collected each hour from grab
samples taken at 20-minute intervals. Composite samples
were collected to reduce variability in radionuclide
concentrations due to inherent system changes.
QA/QC samples including matrix spikes and matrix spike
duplicates (MS/MSD), duplicates, process equipment
blanks, and sample bottle blanks were collected to evaluate
the variability associated with the analytical and sampling
procedures.
29
-------
SAMPLE COLLECTION
OR MEASUREMENT LOCATION
Influent from
Solar Pond
Decant Water
Effluent from
CURE Treatment
System
Filter Cake
Power Supply
LOCATION
IDENTIFIER
L1
M1
L2
M2
S1
M3
M4
M5
MATERIAL
Untreated Water
Untreated Water
Treated Effluent
Treated Effluent
Filter Cake
Filter Cake
None
MONITORING
ACTIVITY
Sample Collection
Measurement
Sample Collection
Measurement
Sample Collection
Measurement
Measurement
Measurement
PARAMETERS
Water Chemistry
Flow Rate, Pumping Period, .
Water Characteristics
Water Chemistry
Water Characteristics
Solids Chemistry and
Characteristics
Volume
Voltage, Amperage
Voltage, Amperage
x
1
M
S
Valve
Flow Direction
Measurement
Location
Solid Sample
Collection Point
Liquid Sample
Collection Point
Screen
Sample
Port
Cure Tubes
Figure 4-2. Sampling and measurement locations.
30
-------
The following approaches were used to achieve the
demonstration's secondary objectives:
Samples were analyzed to demonstrate the CREs for
metals, TOC, TDS, and TSS and to evaluate anode
deterioration
Field parameter and water quality measurements were
obtained every 20 minutes throughout each run to
confirm system stability for the duration of each run.
Samples of dewatered sludge were obtained to deter-
mine metals leachability (including radionuclides)
from the flocculent by TCLP for waste characteriza-
tion.
The volume of sludge generated by the treatment pro-
cess was measured.
All costs associated with each phase of the demon-
stration were documented.
4.3.2 Sampling Analysis and
Measurement Procedures
Water samples were submitted for total uranium,
plutonium-239/240, and americium-241 analysis. Water
samples from test runs 1 and 3 were also analyzed for total
metals, TOC, TDS, and TSS. Samples of influent and
effluent were obtained at locations LI and L2 shown in
Figure 4-2. In addition, sludge samples were submitted for
total uranium, plutonium-239/240, and americium-241
analysis. Sludge samples from test runs 1 and 3 were also
analyzed for total metals, TOC, bulk density, and moisture
content. Sludge samples were collected after test runs 1
and 3 for TCLP analysis.
In addition to sampling and analysis for chemical
parameters, the operating conditions of the treatment
system were evaluated using the measurement data
collected at locations LI and L2 shown in Figure 4-2. For
runs 1 through 4, pH, specific conductivity, dissolved
oxygen, and temperature were measured at sampling ports
LI (influent) and L2 (effluent). Voltage and amperage
measurements were taken from gauges installed on the
treatment system (Ml, M4, and M5). These sampling
locations are shown in Figure 4-2. Flow rate was
calculated from time and volume measurements for each
demonstration run. Power consumption was measured by
the amount of diesel'fuel used by the portable generator.
4.3.3 Operational and Sampling
Problems and Variations from the
Work Plan
Originally, the CURE SITE demonstration was scheduled
to be completed in 35 days. The SITE team, consisting of
EPA's contractors and DOE's operating contractor at
RFETS, experienced several operational problems during
the demonstration. Some of these problems resulted in
changes in the demonstration schedule, while others
required making decisions in the field to solve the
problem. Some of these changes also resulted in
deviations from the work plan contained in the quality
assurance project plan (QAPP) (EPA 1995b). As a result
of these operational problems, the demonstration was
completed over a period of 5 3 days. Site preparation was
completed in 10 days; the preruns, optimization runs, and
demonstration runs were completed in 14 days; and
decontamination and demobilization was completed in 29
days. The problems encountered during the demonstration
and their solutions are presented below. Deviations from
the work plan are also presented.
Pressure buildup within the treatment system due to
an accumulation office in the electrocoagulation tubes
and clogging of bag filters resulted in leaks within
the system. These problems led to delays in the origi-
nal demonstration schedule and resulted in several
additional optimization runs and a retrofit of the treat-
ment system. The inner pipes were replaced with
smaller diameter pipes to allow for more annular space
between the tubes. In addition, nylon screws were
placed along the length of each tube to keep the inner
tube centered within the outer tube. This allowed floc-
culent to pass more easily through the annular space.
However, the tubes still required cleaning after each
run to prevent pressure buildup and to allow data from
all runs to be comparable.
As dictated by the CURE demonstration health and
safety plan (EPA 1995c), screening of all personnel
for alpha and beta radiation by RFETS radiation con-
trol technicians was required upon exiting the bermed
area. Therefore, the SITE team was constrained by
the radiation control personnel work schedule which
also resulted in shorter work days.
31
-------
The bag filters attached to the clarifier filled with floc-
culent and clogged very easily. The bag filter size
was changed from 1 micron which was used during
preruns and optimization runs, to 25 microns for dem-
onstration runs 1,2, and 4. In addition, a 50- micron
bag filter was used during run 3 to allow for increased
flow.
Samples obtained during demonstration runs were
alkaline, with a pH range of 7.7 to 9.6. Large quanti-
ties of acid were required to bring the sample pH to
2.0 for preservation, as stated in the work plan. The
addition of large quantities of acid led to generation
of gases in the samples. Therefore, acid was added
in small increments to each sample to control effer-
vescence. This procedure took much more time.
The work plan stated that two 6,500-gallon tanks
would be used during the demonstration. One tank
to contain untreated water removed from A and B solar
pond sludge (A/B decant water) and the other to con-
tain treated water. However, both tanks were used to
contain treated water. The untreated A/B decant wa-
ter remained in the tanker truck used to transport water
to and from the demonstration site. The tanker truck
was parked inside an inflatable berm to contain any
potential spills.
The work plan stated that the length and diameter of
the clectrocoagulation tubes and the type of metal
tubes used (Al or Fe), were to be determined before
bringing the treatment system on site. The work plan
also stated that only flow rate and amperage would
be changed during the preruns and optimization runs.
However, because of pressure buildup in the system,
flow rate, amperage, and tube diameter were changed
during the preruns and optimization rums. Iron was
the only tube material used.
An effluent process blank was added before com-
mencement of run 1 to evaluate the flushing efficiency
of the treatment system. This additional sample was
not included in the original work plan.
As stated in the work plan, treated effluent was to be
routed to the clarifier to allow for the settlement of
flocculent generated by the treatment system. How-
ever, the developer was concerned that the small-ca-
pacity clarifier would not be able to handle the flow
rates used during the treatment process. Therefore,
samples obtained would not represent the treatment
capability of a larger capacity clarifier, as originally
proposed. Because of this issue, two samples of ef-
fluent water were obtained from sampling port L2.
One sample remained unfiltered and the other sample
was filtered after collection into the composite con-
tainer. This sample was filtered using a 40-micron
filter to mimic settling within a larger capacity clari-
fier as originally proposed in the work plan. Samples
were filtered during transfer from the composite
sample collection container to individual sample
bottles.
The work plan stated that a constant flow rate of 5
gpm would be used throughout runs 1 through 4. As
a result of the optimization runs, the flow rate used
for runs 1 through 4 was 3 gpm.
During the field QA audit of the demonstration, it was
noted by the EPA auditor that the reality short operating
runs required by the operating conditions at the site may
not be representative of the typical use of the CURE
system. Therefore, long-term operating efficiency of the
CURE system should be extrapolated with caution from
the limited data collected during the demonstration.
4.4 Review of Demonstration
Results
This section discusses demonstration results in terms of
the optimization runs and results for critical and
noncritical parameters. The system optimization was
performed to determine the most effective configuration of
the system for treatment of the A/B decant water from the
SEPs at RFETS.
4.4.1 Summary of Results for
Optimization Runs
Five optimization runs were conducted to determine the
most effective configuration of the CURE
electrocoagulation system for treating A/B decant water at
RFETS. Variable parameters included tube material,
diameter, length, and number; annular space between
tubes; flow rate; number of passes through the system; and
applied potential (and associated electrical current).
32
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The configuration used for the demonstration are as
follows:
Iron tube material
Three pairs of concentric tubes
0.1-to 0.5-inch annular space '
One pass through each tube
Flow rate of 3.0 to 3.1 gpm
Applied potential of 20 to 57 volts and accompany-
ing current of 135 to 168 amperes
4.4.2 Summary of Results for Critical
Parameters
A comparison of the first two test runs with the last two
runs indicates that CWQCC standards for plutonium and
americium are most likely to be met when the influent
concentrations of plutonium and americium are low, while
the CREs are greatest when concentrations of these
contaminants are higher. However, higher concentrations
of plutonium and americium may be associated with
suspended solids, and a significant portion may be
removable by prefiltering or settling of the treatment water
prior to treatment.
CREs for Uranium, Plutonium, and Americium
Samples for uranium, plutonium, and americium analysis
were collected from the inflow to the treatment system and
the outflow of the clarifier during each run. Both filtered
and unfiltered samples were collected at the outflow of the
clarifier. The filtered samples were passed through a 40
micrometer (um) nominal pore size filter. CREs were
calculated for each test run using composite data from
influent and both the filtered and unfiltered effluent
concentrations. The results are presented in Table 4-1.
Analytical results from the four runs indicate that the
source water contained similar concentrations of uranium
throughout the demonstration. However, the plutonium
and americium concentrations varied. Plutonium and
americium tend to sorb to particulates. Therefore, the
variation in influent concentrations for these metals is
likely an artifact of positioning of the tanker truck
supplying the source water resulting in different amounts
of sediment being pumped into the system. The first two
runs were conducted with mean influent concentrations of
0.221 and 0.197 pCi/L of plutonium, and 0.202 and 0.172
pCi/L americium. Plutonium and americium concentrations
for runs 3 and 4 were more than 100 times these values.
CREs were calculated for each run based on mean influent
and effluent concentrations (see Table 4-1). The mean
CREs for uranium were 43 percent for unfiltered effluent
and 44 percent for filtered. While these results indicate
that uranium concentrations were reduced considerably,
the objective of 90 percent contaminant removal was not
achieved. Uranium removal was not as high as expected
based on results of the bench-scale treatability study.
Results from the treatability study indicated at least 94
percent removal efficiency for uranium, with an influent
uranium concentration that was comparable to the influent
concentration in the demonstration.
It is likely that the operational parameters used in the
demonstration were not optimal for uranium removal.
More complete system optimization and treating
wastewater with multiple runs through the CURE system
may improve uranium removal efficiencies.
The removal efficiencies for plutonium and americium
were much higher than for uranium. Results from run 1 are
comparable to those of run 2, and results from runs 3 and 4
are comparable. However, results from runs 1 and 2 are
very different than results from runs 3 and 4. Therefore,
the results from the first two runs are presented separately
from the results of runs 3 and 4. The reason for such
different results appears to be related to the higher influent
concentrations of plutonium and americium in runs 3 and
4.
The average CRE for plutonium in the first two runs was
72 percent for the unfiltered effluent and 83 percent for the
filtered effluent. Average CREs for americium were 74
percent for unfiltered and 70 percent for filtered effluent.
These results are below the 90 percent removal objective,
although significant removal was observed.
Higher influent concentrations of plutonium, americium,
and TSS were observed in the influent for runs 3 and 4. A
change in the orientation of the tanker truck supplying the
system with influent was likely responsible for this. The
increased concentration of TSS, along with the sorptive
nature of these two radionuclides, suggests that the
plutonium and americium were primarily in the solid or
sorbed state, and that prefiltering may have reduced these
influent concentrations considerably. The CREs for
plutonium and americium in runs 3 and 4 were all 97
percent or better. However, the treated effluent
concentrations of these contaminants for both runs was
higher than the influent concentration for runs 1 and 2.
33
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Table 4-1. Radionuclide Concentrations in Wastewater
Parameters
Units
Run 1 Influent
Effluent (unfiltered)
CRE
Effluent (filtered)
CRE
Run 2 Influent
Effluent (unfiltered)
CRE
Effluent (filtered)
CRE
Run 3 Influent
Effluent (unfiltered)
CRE
Effluent (filtered)
CRE
Run 4 Influent
Effluent (unfiltered)
CRE
Effluent (filtered)
CRE
Notes:
pCi/L KcoCuries per liter
fig/L Micrograms per liter
CRE Contaminant removal efficiency
Uranium
we/L
2,800
1,900
32%
1,900
32%
2,900
1,600
44%
1,600
44%
2,600
1,400
46%
1,400
47%
2,600
1,300
51%
1,300
52%
Plutonium
nCi/L
0.221
0.082
63%
0.041
82%
0.197
0.039
82%
0.032
84%
33.1
1.03
97%
0.434
99%
26.6
0.706
98%
0.199
99%
Americium
DCi/L
0.202
0.051
75%
0.062
69%
0.172
0.049
72%
0.051
71%
83.5
2.49
97%
0.755
99%
60.5
1.46
98%
0.342
99%
34
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Confidence limits cannot be calculated for these results
because results for more than two tests are required for the
calculations.
CWQCC Standards for Uranium, Plutonium, and
Americium
CWQCC discharge standards are 15 g/L for uranium, and
0.05 pCi/L for both plutonium-239/240 and americium-
241. CWQCC standards for uranium were not met during
the CURE demonstration. The lowest average effluent
concentration of uranium for any run was 1,270 g/L, more
than 250 times the CWQCC standard. However, a
minimum CRE of 99.8 percent would be required to
achieve the CWQCC standard with the influent water used
in this demonstration.
CWQCC standards for plutonium were met for the filtered
effluent of run 1 and both the unfiltered and filtered
effluent of run 2, and the CWQCC standard for americium
was met in the unfiltered effluent of run 2. The highest
average effluent concentration of both contaminants in
runs 1 and 2 was 0.0817 pCi/L, which is 63.4 percent
higher than the CWQCC standard. The CWQCC standard
for these contaminants was exceeded by 398 percent or
more in both runs 3 and 4.
4.4.3 Summary of Results for
Noncritical Parameters
Anode Deterioration
Examination of the electrocoagulation tubes revealed
severe thinning of the tube walls, indicating that extensive
anode deterioration had occurred during the demonstration
runs. Sludge and effluent iron concentrations from test
runs 1 and 3 suggest that nearly all of the tube material
precipitates. These results are presented in Tables 4-2 and
4-3.
CREs for Other Contaminants
Table 4-4 lists the influent and effluent metals, TOC, TDS,
and TSS concentrations for runs 1 and 3. These
constituents were not analyzed in runs 2 and 4. Arsenic
removal was the most significant with an average CRE for
the two runs of 77 percent. Calcium removal was
unexpected, but averaged approximately 50 percent.
Magnesium and TOC removals were slight with 15 and 12
percent averages, respectively. No significant removal of
boron, lithium, or TDS was observed, and iron
concentrations in the effluent increased by more than an
order of magnitude in both runs. CREs could not be
Table 4-2. Metal Content in Dewatered Sludge
Parameter
Aluminum
Arsenic
Boron
Cadmium
Calcium
Iron
Lithium
Magnesium
Units
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Runl
<10.0
5.5
<10.0
<0.50
282
19,800
<5.0
1,120
Run 3
33.0
17.8
15.6
0,65
2,400
49,800
<5.0
1780
Notes:
mg/kg milligrams per kilogram
< less than reported detection limit
35
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Table 4-3. Metals Concentrations in Wastev/ater
U)
0\
Parameter
Aluminum
Arsenic
Boron
Cadmium
Calcium
Iron
Lithium
Magnesium
TOC
IDS
TSS
Units
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
Avg Influent
<0.20
0.11
2.6
<0.01
16.3
NA
2.3
122
128
8,410
10.5
Raul
Avg Effluent
(Unfiltered)
<0.20
0.026
2.53
<0.01
9.73
12.5
2.27
100
78.7
8,330
32.4
Avg Effluent
(Filtered)
NA
0.0237
2.47
<0.01
10.4
6.4
2.27
99.4
108
8,270
18.4
Avg Influent
0.29
0.1367
2.47
<0.01
42.6
0.257
2.1
126
106
8,510
50.4
Run 3
Avg Effluent
(Unfiltered)
<0.20
0.0343
2.43
<0.01
19.1
12.1
2.07
110
111
8,460
54.23
Avg Effluent
(Filtered)
<0.20
0.0287
2.5
<0.01
19.3
5.27
2.13
112
113
8,360
31.2
CWQCC*
Standards .
0.1
0.05
0.75
0.0015
NS
0.3
NS
NS
NS
NS
NS
Notes:
mg/L milligrams per liter
< less than reported detection limit
NA not analyzed
NS no standard
-------
Table 4-4. Radionuclide Content in Dewatered Sludge
Parameter
Units
Notes:
mg/kg milligrams per kilogram
pCi/L picoCuries per liter
Runl
Run 2
Run 3
Run 4
Uranium
Plutonium
Americium
mg/kg
pCi/g
pCi/g
77
0.189
0.182
120
0.178
0.115
120
34.0
95.8
96
23.0
66.4
determined for aluminum or cadmium because the
concentrations were too low in both the influent and the
effluent. Changes between influent and effluent
concentrations of TSS are inconsistent, suggesting that
residence time in the clarifier was not sufficient to
adequately remove the solids from suspension.
Hydrogen and Chlorine Gas Production
Chlorine and hydrogen gases were possible by-products of
the electrocoagulation process. Results of air monitoring
over the open clarifier during the test runs did not indicate
a hazard due to emission of these gases under the
conditions of the demonstration.
Power Consumption
The CURE treatment system was operated using a diesel
powered 50-kilowatt generator. Fuel consumption during
the demonstration was approximately 8 gallons per hour of
operation of the CURE treatment system.
Optimum Operating Parameters
The results of the five optimization runs indicated that the
following operating parameters would be adequate for
treating the A/B decant water with the CURE system:
Iron tube material for all tubes
10-foot long electrocoagulation tubes
0.1 to 0.5 inch annular spacing between inner and
outer tubes
Three 10-foot long tube sets (concentric pairs)
One pass through each tube
Flow rate of 3.0 to 3.1 gpm
Applied potential of 20 to 57 volts to achieve an elec-
trical current of 135 to 168 amperes
These are the conditions used for all four demonstration
runs.
Geochemical Characteristics
The four water geochemical characteristicspH, specific
conductivity, dissolved oxygen, and temperaturewere
measured at 20-minute intervals throughout the four test
runs. Measurements were taken for both the influent and
effluent waters. Table 4-5 summarizes these parameter
measurements.
Influent and effluent pH were similar throughout the
demonstration. Generally, pH varied between 8.5 and 9.5,
although extremes of 7.77 and 9.66 were recorded.
Average specific conductivity at LI was 10.9 millisiemens
per centimeter (mS/cm), and that at L2 was 11.4 mS/cm.
These results suggest that some ions in solution were
replaced with more conductive ones by the CURE system,
37
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Table 4-5. Geochemical Characteristics Summary
Parameter Range
00
Run Sample Port
1 LI
L2
2 LI
L2
3 LI
L2
4 LI
L2
pH
8.73-8.86
8.55-9.48
8.88-9.21
7.86-9.66
8.70-8.92
8.23-9.60
8.56-8.73
7.77-8.95
Specific
Conductivity
(mS/cm)
10.2-10.6
9.5-11.9
11.2-11.8
10.7-11.4
9.54-11.9
11.0-12.3
10.9-11.5
10.6-11.9
Dissolved
Oxygen
(mg/L)
1.90-3.60
ND*-8.69
1.70-2.54
ND-3.10
1.11-2.44
ND-2.38
1.58-2.81
ND-3.06
Temperature (°C)
28.2-30.2
29.6-36.3
27.2-29.2
27.7-35.4
28.1-30.5
27.1-35.7
26.2-27.0
27.7-33.8
Potential (V)
20-57
20-57
23-57
22-57
25-50
25-50
25-52
25-52
Current
(Amp)
135-160
135-160
138-158
138-158
140-168
140-168
150-162
150-162
Flow (gpm)
3.0-3.1
3.0-3.1
2.8-3.1
2.8-3.1
3.0
3.0-3.1
3.0-3.1
2.9-3.1
Pressure
(psO
73-83
74-83
43-59
43-59
29-43
29-43
21-23
21-23
*ND = Not detectible, detection limit approximately 1 mg/L
Notes:
mS/cm millisiemens per centimeter
mg/L milligrams per liter
°C degrees Celsius
V volts
A amperes
gpm gallons per minute
psi pounds per square inch
-------
although TDS did not change. This may occur by breaking
bonds in uncharged complexed ions in the influent
solution.
The influent typically contained between 2.0 and 3.0 mg/
L dissolved oxygen, indicating slightly reducing
conditions. Dissolved oxygen content of the effluent
during the first 30 minutes of operation indicate that
oxygen is depleted from the process water by the
formation of the floe in the CURE system. Effluent
between the CURE system and the clarifier did not contain
measurable concentrations of oxygen during this time.
Later measurements were collected at the outlet from the
clarifier. These measurements indicated similar reducing
conditions to the influent. These results suggest that
oxygen is the limiting reagent in the formation of the
flocculent, and that aerating the influent may increase the
removal efficiency of the system by precipitating more of
the iron in the effluent.
Temperature of the influent during the three hours after the
clarifier had filled was similar to the temperature of the
effluent during the first 30 minutes of operation, but
measurements made after the clarifier had filled were as
much as 6°C higher than the influent. These results
suggest that the water in the clarifier had been warmed by
the warm days. Temperature comparisons are
inconclusive since temperature measurements of the
influent were not made during the first 30 minutes of
operation, and heating of the process water in the tanker
truck may have occurred during the day.
TCLP Results
Tables 4-2 and 4-4 show the metals and radionuclides
content in the dewatered sludge. Results indicate that the
radionuclides were highly concentrated in the dewatered
sludge, especially plutonium and americium in sludge
from runs 3 and 4. Table 4-6 presents TCLP results for
radionuclides. Although no TCLP regulatory limits exist
for uranium, plutonium, and americium, these radionuclides
were analyzed to characterize the leachability of the waste.
Analyses of the TCLP leachate indicate that uranium
concentrations in the leachate exceed the CWQCC
standard of 15 g/L by as much as a factor of 30, while
plutonium and americium concentrations are below or
near their standard of 0.05 pCi/L. For comparison, it
should be noted that the maximum concentration for the
toxicity characteristic for the TCLP metals is typically 100
times that of the EPA MCLs for groundwater (EPA 1995a
and 1995b).
TCLP results indicate that metals were not detected above
TCLP detection limits. These results suggest that the
sludge is stable and metals are resistant to leaching.
Operation Costs
A detailed cost analysis is presented in Section 3 of this
report. The analysis examined costs for a 100 gpm
treatment system operating for 1, 5, and 10 years. Costs
ranged from $0.009 per treated gallon for the 1-year
Table 4-6. Radionuclide Concentration in TCLP Leachate
Parameter
Notes:
mg/L
pCi/L
Units
Runl
Run 2
Run 3
Run 4
Uranium
Plutonium
Americium
mg/L
pCi/L
pCi/L
0.44
0.014
0.0049
0.21
0.022
0.022
0.32
0.055
0.160
0.25
0.081
0.270
Milligrams per liter
PicoCuries per liter
39
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operation to $0.003 per treated gallon ,for the 10-year
operation. Actual costs will vary based on type and
location of installation.
4.5 Conclusions
The primary objectives of the CURE electrocoagulation
demonstration were not met. However, removal of
radionuclides in the A/B decant water at RFETS was
significant, and CWQCC standards were met for
plutonium and americium in some cases, but the target
confidence level of 95 percent was not met.
Significant removal was also observed for arsenic (74
percent) and calcium (50 percent) indicating that CURE
effectively reduces concentrations of these elements.
TCLP analyses of sludge produced by the CURE
technology during this demonstration indicate that the
solid wastes may be classified as nonhazardous.
40
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Section 5
Technology Status
The CURE technology has been installed in many
industrial locations. According to the technology
developer, installed applications include metals removal
from plating companies and manufacturing operations,
steam cleaning, bilge water treatment, drilling fluids,
groundwater, mine waters, paint booths, and food industry
wastes. Additional testing has been performed on many
other industrial wastewaters.
The treatment unit used in this demonstration is trailer
mounted and ready for use. It can be mobilized to any site
on short notice for testing. GEC is currently constructing
a transportable treatment unit that will be capable of
treating wastewater at a rate of approximately 50 gpm. The
unit will be mounted on a trailer that can be transported by
a semitractor. It is not known when this unit will be
available for service. Waste streams greater than 50 gpm
will require a larger CURE system. These systems are
custom designed for the application.
41
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Section 6
References
Barkley, N.P., C.W. Fan-ell, and T.W. Gardner-Clayson.
1993. Alternating Current Electrocoagulation for
Superfund Site Remediation. J. Air & Waste Mgmt.
Assoc. Volume 43, Number 5. Pages 784-769.
Dalrymple, C.W. 1994. Electrocoagulation of Plating
Wastcwaters. American Electroplaters and Surface
Finishers Society Environmental Protection Agency
15th Conference on Pollution Prevention and Con-
trol. January.
Drever, James I. 1988. The Geochemistry of Natural
Waters. Prentice Hall. Englewood Cliffs, NJ. Sec-
ond edition.
EG&G Rocky Flats, Inc. (EG&G). 1991. Pond Sludge
and Clarifier Sludge Waste Characterization Report.
Evans, G. 1990. Estimating Innovative Technology Costs
for the SITE Program. Journal of Air and Waste
Management Association, 40:7, pages 1047 through
1055.
Hydrologies, Inc. 1993. CURE - Electrocoagulation
Wastewater Treatment System, USEPA Superfund
Innovative Technology Evaluation (SITE) Program,
Proposal No. SITE-008,05.
Jenke, Dennis R. and Frank E. Diebold. 1984.
Electroprecipitation Treatment of Acid Mine Waste-
water. Water Research. Volume 18, Number 7. Pages
855-859.
Office of Federal Register. 1993. Code of Federal Regu-
lations Title 40, Protection of Environment. U.S.
Government Printing Office. Washington, D.C. July
1993.
Renk, R.R. 1989. Treatment of Hazardous Wastewaters
by Electrocoagulation. Proceedings Ninth National
Symposium on Food Processing Wastes, Denver,
Colorado, Page 264. EPA-600/2-78. August.
Rockwell International. 1988. Rockwell International Cor-
poration, Resource Conservation and Recovery Act,
Post Closure Care Permit Application, Appendix 1-
2, Solar Evaporation Ponds. July. Golden, CO.
Sawyer, ClairN. and Perry L.McCarty. 1978. Chemistry
for Environmental Engineering. McGraw-Hill Book
Co. New York. Third edition.
U.S. Department of Energy (DOE). 1980. U.S. Depart-
ment of Energy, Rocky Flats Plant, Final Environ-
mental Impact Statement, DOE/EI5-0064.
U.S. Environmental Protection Agency (EPA). 1991. Fed-
eral Facility Agreement and Consent Orders. Den-
ver, Colorado. January.
EPA. 1994. Test Methods for Evaluating Solid Waste,
Volumes IA-IC: Laboratory Manual, Physical/
Chemical Methods; and Volume II: Field Manual,
Physical/Chemical Methods, SW-846, Third Edition
(revision 3), Office of Solid Waste and Emergency
Response, Washington, D.C.
EPA. 1995a. Superfund Innovative Technology Evalua-
tion Program CURE Electrocoagulation Technology
Treatability Study Report. July 10.
EPA. 1995b. Final Quality Assurance Project Plan for
General Environmental Corporation CURE Electro-
coagulation Technology Demonstration at the Rocky
Flats Environmental Technology Site, Golden, Colo-
rado. July.
42
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EPA. 1995c. Final Health and Safety Plan, CURE SITE
Demonstration, Rocky Flats Environmental Technol-
ogy Site, Golden, Colorado. August.
Vik, EilenA., Dale A. Carlson, Arild S. Eikum, andEgilT.
Gjessing. 1984. Electrocoagulation of Potable Wa-
ter. Water Research. Volume 18, Number 11. Pages
1355-1360.
43
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Appendix A
Vendor Claims for the Technology
This appendix presents the claims made by the vendor,
General Environmental Corporation (GEC), regarding the
CURE technology under consideration. This appendix
was written solely by GEC, and the statements presented
herein represent the vendor's point of view based on
demonstrations and commercial operation performed
since 1990. Publication here does not indicate EPA's
approval or endorsement of the statements made in this
section; EPA's point of view is discussed in the body of
this report.
The demand for improved methodologies and technologies
to remove metallic pollutants from water has increased
dramatically during the past few years due in part to
expanded waste management activities; stricter National
Pollutant Discharge Elimination System (NPDES) and
publicly owned treatment works (POTW) discharge
permit limits; the federal government's commitment to
remediate National Priorities List (NPL) radioactive sites;
increased public awareness of environment; economic
factors; and legal liability issues. The U.S. Department of
Energy (DOE) has outlined a long-term plan committing
the agency to clean up 45 years worth of accumulated
contamination at nuclear weapons sites and facilities. As a
result, DOE has scheduled environmental remediation
activities for more than 3,700 radionuclide and hazardous
chemical waste sites. These DOE sites taken together with
the thousands of Superfund sites with metal (and
sometimes radionuclide) contamination represent a
massive remediation problem that will present a
tremendous fiscal and technological challenge in the
future.
At an estimated two-thirds of the DOE and Superfund
sites, groundwater, stored water, pond water, or sludges
and soils are contaminated by metals. DOE's 26 NPL
radioactively contaminated sites essentially all have
metals and radionuclide problems. They range from
uranium and thorium, to low-level radioactive wastes
(LLRW), to nuclear weapons production and processing
wastes representing uranium, enriched uranium, and
transuranic (TRU) materials. Federal statutes require that
remediation restoration of these federal sites be carried out
in compliance with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA)
and the Superfund Amendments and Reauthorization Act
(SARA).
CERCLA as amended by SARA establishes a cleanup
program intended to:
Encourage the use of cost-effective methods
Promote remedial actions that should yield perma-
nent solutions
Minimize secondary waste streams
Use alternative treatment technologies
Conform to applicable or relevant and
appropriate requirements (ARAR)
Protect human health and the environment
The chemistry of heavy metal and radionuclide pollutants
varies from site to site, presenting a remediation challenge
for achieving strict discharge standards. Conventional
filtration, sorption, and ion exchange methods have proved
useful for removing macro- to micro-particle inorganic
metallic forms from water, but are limited by performance
and cost when large volumes of trace metals and
radionuclides must be removed. Particle filtration is not
efficient for removing trace micromolecular and ionic
metallic forms from water. Microfiltration readily
removes 0.025- to 10-micron particles from water, but has
generally been limited in the molecular to ionic range.
44
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Ultrafiltration is widely used for treating small volumes of
liquids containing low total suspended solids (TSS)
concentrations, but is limited in throughput and capacity
for most metals and radionuclide remedial applications.
Ion exchange methods have broad utility for the removal of
anionic and cationic soluble metallic ions, but have
microchanneling, bed, and residual problems, higher
operational costs, and higher disposal costs for
radionuclide-contaminated spent bed material. Reverse
osmosis is highly efficient for removing a wide range of
soluble inorganic metallic ions, but can be expensive to
operate and may not remove trace metals and
radionuclides existing as complexed, chelated forms. In
addition, the salt brine waste produced by this
methodology contributes to the waste disposal problem.
A.1 CURE System
The CURE treatment system is a refinement of
electrocoagulation technology that has existed since the
early 1900s. Electrocoagulation uses electricity to
destabilize contaminants and allow van der Waals' force to
coagulate and precipitate the contaminants. In
conventional coagulation and precipitation, a chemical
amendment is added to the contaminated water. The
amendment destabalizes and binds with oppositely
charged contaminants in solution, causing them to
coagulate and precipitate. By eliminating the chemical
additives, the residual wastes are reduced.
The CURE system, a patented electrocoagulation process,
allows continuous water flow through concentric
electrocoagulation tubes. The system circumvents some
of the performance limitations of conventional methods
, used to remove metals and radionuclide pollutants from
water, allowing higher flow rates and greater removal
efficiencies. In addition, residual wastes produced by
treatment are reduced and less subject to leaching that
other methods.
Electrocoagulation does not remove materials that do not
form precipitates, such as sodium and potassium. If a
contaminant does not form a precipitate, electrocoagulation
will not cause it to flocculate. Therefore, electrocoagulation
will not remove highly soluble contaminants, such as
benzene, toluene, or similar organic compounds.
General Environmental Corporation (GEC) has refined
this system for commercial applications. The trailer
mounted system is self contained and capable of
installation in limited space areas and the configuration
can be customized to specific applications by altering the
tube materials used and flow sequencing.
A.2 Design and Product Improvements
The Rocky Flats Environmental Technology Site
(RFETS) SITE demonstration of the CURE system in
August and September 1995 -showed that the basic
engineering and system design configuration were
adequate. Still, several system refinements are planned to
improve the equipment for higher flow rates (up to 100
gallons per minute [gpm]), improve system reliability,
increase performance efficiency, and reduce operational
costs. Examples of planned improvements to the CURE
SITE demonstration configuration are outlined below.
Commercial applications can be custom designed with
additional banks of electrocoagulation tubes which
will allow for increased flow rates.
A redundant set of electrocoagulation tubes can be
installed allowing tube servicing and replacement with
no operational down time.
The clarifier will be replaced with one engineered to
meet specific requirements of the application and
anticipated flow rates. Due to time and budget limi-
tations an existing conical clarifier was used for the
CURE demonstration in place of the slant-plate clari-
fier engineered for the system. Smaller clarifier vol-
umes and increased clarifier performance will result
from the future replacement.
The bag filter used during the CURE demonstration
will be replaced by a filter press which will increase
the system capacity and reduce delays associated with
the bag filter.
A.3 Applications of the System
The CURE system can be used as an in-line system
mounted on a trailer of skid. Examples of commercial and
government project applications are provided below.
Remediation of metals and radionuclides from
groundwater, wastewater, and washing operations
Treatment of manufacturing wastewater
containing metals and oil
45
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» Oil and water separation from process
wastewaters
Removal of metals and oil from waters
Several case studies discussing these application are
presented in Appendix B.
A.4 Factors that Decrease Performance
Bench- and pilot-scale testing should be carried out at each
project to achieve high percent removal efficiency for
identified pollutants. These tests enable system operators
to optimize the system parameters and identify the
presence of competing or inhibiting chemical or physical
factors. For the CURE system, several factors have been
identified that can limit the technology's performance and
increase treatment costs.
Operation of the CURE electrocoagulation system may be
affected by wastewater characteristics such as hydrogen
ion concentration (pH), oxidation/reduction potential
(Eh), specific conductance, temperature, and the amount
of total dissolved and suspended solids (TDS and TSS).
Solution characterization is therefore important to
establish maximum contaminant precipitation, minimize
power use, reduce sludge formation, curtail tube scaling,
and limit anode deterioration.
A.5 Advantages of Methodology
The CURE system offers several advantages over
conventional filtration, ion exchange, reverse osmosis,
and chemical coagulation methods for the treatment and
remediation of metallic cater pollutants. Examples of
advantages include:
Efficient equipment design allows versatile system
installation in space limited areas.
Generation of substantially lower quantities of re-
sidual waste per unit volume of water treated than
other methods which translates to lower land disposal
costs for hazardous and radioactive wastes.
Residual wastes capable of passing the EPA toxicity
characteristic leaching procedure (TCLP) allowing for
less expensive disposal costs.
System capable of operating without additional addi-
tives which results in less residual waste
production.
Demonstrated ability to treat a variety of
contaminants including metals, colloids, suspended
solids, oils, dyes, and organics.
46
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Appendix B
Case Studies
This appendix contains representative examples provided
by the technology developer, GEC, of the cleanup and
recovery (CURE) electrocoagulation technology.
Analytical test data for estimating performance are also
presented by GEC, where available. .Additional
documentation on these studies may be obtained from
GEC. Publication here does not indicate EPA's approval
or endorsement of the statements made in this section;
EPA's point of view is discussed in the body of this report.
The following are case studies that represent a wide
spectrum of metals and radionuclide treatment conditions
for industrial wastewater and U.S. Department of Energy
(DOE) facility wastes.
B.1 Municipal Wastewater Treatment
An Iron Ore Treatment Plant near Denison, Texas,
employs approximately 13,000 people. The plant uses
orbital aeration basins for primary treatment of municipal
wastewater, followed by clarification and aerobic
digestion. The resulting sludge is dried in open air beds
then removed for disposal.
The plant had difficulty operating within the scope of its
permit due to an increase in influent volume due to growth.
The facilities inability to treat additional influent also
affected the economic growth of Denison.
The CURE system was tested at the Iron Ore Treatment
Plant. It treated effluent at approximately 200 gallons per
minute. The treated waste stream was allowed to settle in
a 27,000-gallon vertical clarifier for approximately 2
hours. Clear water was then drawn off and discharged to
the second ring of the plant's orbital system. A very high
quality and low water sludge was passed directly to the
drying beds, bypassing polymer application and treatment
in anaerobic digesters. The CURE system reduced the
suspended solid levels by 98 percent, to a range of 1,3 00 to
5,000 parts per million (ppm).
Treatment goals were achieved by running the CURE
system for approximately 12 hours per day, five days a
week. In a 24-hour period, the CURE system processed an
average of 144,000 gallons of effluent. At this level of
processing, the plant operated at the required level of
efficiency.
The CURE system increased the capacity of the plant
while bringing plant effluent into compliance with
discharge standards. The CURE system reduced capital
expense, enhanced treatment capability, and improved
throughput. The CURE system was used until a new,
larger capacity wastewater treatment plant was built.
B.2 Treatment of Manufacturer
Wastewater
A tractor manufacturer generated approximately 30,000
gallons of wastewater per day from the production of
approximately 30 to 50 units annually. The waste stream
consisted of water-borne contamination including zinc,
chrome, oil and grease, paint sludge, and a material similar
to cosmoline which is used for temporary protection of
unfinished metals. Because of this wide range of
contaminants, a multiple pass CURE system treatment
was designed using anodes of different materials.
Following treatment by the CURE system, the effluent
flowed to a dual clarifier. Approximately 2 to 3 ppm of
polymer was added to enhance the settling characteristics
of the sludge.
The clear water effluent was discharged to the publicly
owned treatment works. The sludge was passed through a
47
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filter press, then transported to a permitted disposal
facility. The system performed as designed, with all levels
of contaminants reduced to or below target values. Zinc,
the primary constituent in the effluent stream, was
consistently measured at 0.15 to 0.2 ppm, well below
discharge limits.
The CURE system replaced the manufacturer's chemical
precipitation system, which was extremely labor intensive
and costly at approximately $0.125 per gallon. The CURE
system, including labor, capital amortization, maintenance,
and consumable materials, was treating the wastestream
for approximately $0.055 per gallon.
B.3 OH and Water Separation of Steam
Cleaner Wastewater
Several CURE systems have been installed in facilities
that use steam equipment to remove oil, dirt, grease, and
other materials from oil field equipment. The system is
particularly valuable where there is a problem with the
separation of oil and water containing concentrations of
metals.
At these facilities, the CURE system is the central
treatment element, with pH adjustment preceding and
clarification following electrocoagulation. The following
results presented in Table B-l show the effectiveness of
the CURE process on this type of waste. Cost reductions
of up to $3,000 per month are not unusual.
B.4 Treatment of Ship Bilgewater
In August 1992, the U.S. Coast Guard (USCG) approved
the use of the CURE system for the treatment of 176,200
gallons of ship bilgewater at Kodiak Island near
Anchorage, Alaska. The ship bilgewater was contaminated
with high concentrations of oil and metals. A summary of
contaminant removal efficiencies for raw and treated
bilgewater samples is shown in Table B-2. The CURE
process was effective in removing oil and metals with
removal efficiencies ranging between 71 and 99 percent.
Effluent samples were taken following treatment by the
CURE system and prior to entering the 300- gallon
clarifier. Because of the small clarifier and limited
retention time, an anionic polymer was added to the
sedimentation as a coagulant aid. Following retention in
the clarifier, the effluent passed through activated carbon
filters for final polishing and removal of any trace
hydrocarbons.
The volume of the waste was reduced by 98 percent, from
46,500 gallons of bilgewater to less than 600 gallons of
sludge.
The mobility of the CURE equipment eliminated the need
to transport the bilgewater for treatment off the island
resulting in an estimated cost savings of $185,000. The
average cost of treating the bilgewater on-site, estimated at
$0.45 per gallon was approximately 10 percent of the cost
for treatment on the island.
B.5 Los Alamos National Laboratory
Treatability Study
In November 1994, GEC tested the CURE system on
wastewater at the Los Alamos National Laboratory
(LANL) in Los Alamos, New Mexico. The primary
objective of the tests was to compare the CURE
electrocoagulation process with the conventional methods
of chemical treatment.
The wastewater treated was a grab sample from the
influent to LANL hazardous wastewater treatment plant
and contained plutonium, americium, and various other
metals. The focus of the treatability study was on the
radionuclides.
The CURE process was more efficient than the chemical
treatment process in one of three test runs. However,
LANL was pleased with the results and requested
additional testing of the CURE system. Table B-3
summarizes the results of the testing.
B.6 Rocky Flats Environmental
Technology Site Treatability Study
In April 1995, a bench-scale study was conducted by GEC
testing the ability of the CURE system to remove uranium,
plutonium, and americium from water derived from the
U.S. Department of Energy's Rocky Flats Environmental
Technology site solar evaporation ponds (SEPs).
As part of the manufacturing processes at RFETS near
Golden, Colorado, wastes were produced that contained
uranium, plutonium-23 9/240, americium-241, and other
contaminants. Some of this waste was collected in SEPs.
The SEPs stored and treated liquid process waste having
48
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less than 100,000 picoCuries per liter of total long-lived
alpha activity. Water decanted from the sludge and liquid
from the A and B SEPs was treated for this bench-scale
study.
Testing of the CURE system using decant water from the
SEPs indicated that the technology is capable of
consistently removing more than 95 percent of the
uranium, plutonium, and americium.
Table B-1. Treatment of Steam Cleaner Wastewater
Element
Before Treatment
(ppm)
NOTES:
ppm parts per million
After Treatment
(ppm)
Percent Removal
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Silver
Thallium
Vanadium
Zinc
<0.01
0.30 -
8.0
<0.01
0.141
7.98
0.13
6.96
7.4
0.003
0.18
0.4
< 0.005
<0.01
<0.10
0.23
19.4
0.014
<0.01
<0.10
<0.01
0.031
0.05
<0.05
<0.05
1.74
< 0.001
0.035
<0.05
< 0.005
<0.01
<0.10
<0.01
1.20
99
97
99
0
78
99
62
99
76
67
81
87
0
0
0
96
94
49
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Table B-2. Contaminant Removal Efficiencies
Concentration (mg/L)
Untreated
Treated
% Removal
Contaminant
Petroleum hydrocarbons
Heavy Metals
Aluminum
Boron
Iron
Zinc
Dissolved Cations
Calcium
Magnesium
Manganese
Sodium
Potassium
Dissolved Anions
Phosphorus
72.5
4.16
4.86
95:4
3.41
293
943
0.93
8,690
287
5.38
. . *«,
ND(0.2)
0.74
1.41
ND(l.O)
, NP(0.5)
137
300
ND
5,770
222
1.43
99.0
82.0
71.0
99.0
99.0
53.2
68.2
99.0
33.6
23.0
73.4
NOTES:
mg/L milligrams per liter
ND not detected
50
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Table B-3. Analytical Results for Radionuclides in LANL Wastewater
Sample
No.
Raw
Elec-4
Elec-5
Elec-6
Jar-1
Jar-2
Jar-3
Plutonium
pCi/L
15,560
3,2
32.8
10,400
18.6
35.4
4,310
After
Treatment
DCi/L
N/A
0.0006
0.0688
6,990
0.0223
0.0814
1,190
%
Removal
N/A
99.98
99.79
32.98
99.88
99.77
72.31
Americium
pCi/L
1,970
2.8
12.4
1,670
6.9
1.9
783
After
Treatment
pCi/L
N/A
0.00392
0.07812
1,423
0.0241
0.00190
311
% Removal
N/A
99.86
99.37
15.00
99.65
99.90
60.23
NOTES:
PCi/L picocuries per liter
N/A not applicable
51
6U.S. GOVERNMENT PRINTING OFFICE: 1998-653-686
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