United States
Environmental Protection
Agency
Air And Radiation
(6601J)
EPA 402-R-97-006
July 1997
Mixed Was
Groundw

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United States                       Air and Radiation         EPA 402-R-97-006
Environmental Protection Agency	(6601J)	July 1997	
  RESOURCE GUIDE FOR ELECTROKINETICS LABORATORY AND
      FIELD PROCESSES APPLICABLE TO RADIOACTIVE AND
 HAZARDOUS MIXED WASTES IN SOIL AND GROUNDWATER FROM
                             1992 TO 1997
                           September 30,1997
                             Prepared/or:
                   U.S. Environmental Protection Agency
                     Office of Radiation and Indoor Air
                       Radiation Protection Division
                Center for Remediation Technology and Tools
                            Washington, DC

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                                      Disclaimer

Although this document has been published by the U.S. Environmental Protection Agency, it does
not necessarily reflect the views of the Agency, and no official endorsement should be inferred.
Mention of  trade  names  or commercial products  does not  constitute  endorsements  or
recommendation for use.

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                                         Preface

A goal of the Environmental Protection Agency/Office of Radiation and Indoor Air/Center for
Remediation  Technology  and Tools  (EPA/ORIA/CRTT) is to bring innovative remediation
technologies for radioactive and hazardous mixed wastes to the Office of Air and Radiation.  This
involves investigating any techniques which show promise in  meeting EPA cleanup standards for
hazardous waste in soil and groundwater. The electrokinetic remediation technology utilizes electric
currents to extract radionuclides, heavy metals, organics and hazardous mixed waste from a porous
medium. This resource document compiles a list of all electrokinetic processes used on a patented,
bench, pilot, field or conceptual scale from the period 1992 to 1997.  It is intended to be used by
anyone interested in learning about the work that has occurred in the field of electrokinetics or by
environmental management and scientists responsible for identifying and selecting a remediation tool
for use at sites containing radioactive materials.

The information obtained in this report, adheres to the approved Data Quality Objectives (DQO) and
Quality Assurance Program Plan (QAPP) for this document. The information was obtained by the
use of the Internet, other documents, and by information received from various facilities upon request.
This report tried to be consistent in the information cited for each electrokinetic process. However,
this depended upon the availability of information. Therefore, some electrokinetic processes may
appear to be more descriptive than others. If more in-depth information (e.g. biodegradation effects,
hydraulic conditions, transport, sorption, precipitation and dissolution reactions) is desired for a
particular electrokinetic process, then it is  advised to contact the facility directly.

This project is coordinated by the EPA/Office of Radiation  and Indoor Air (EPA/ORIA).  The
principal authors are Barrett Riordan and Rohit Karamchandani from Jack Faucett Associates, Inc.
EPA/ORIA acknowledges all reviewers for their valuable observations and comments.

Questions and comments can be addressed to:

                    Robin Anderson/Project Manager
                    EPA/Office of Radiation and Indoor Air
                    401 M Street, SW (6603 J)
                    Washington, DC 20460
                    (202) 233-9385

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                                 TABLE OF CONTENTS
Section                                                                              Page

Table of Contents  	ii
List of Tables	 iii
List of Figures	 iv

Introduction and Summary  	1

Category A:   Electrokinetic processes which are currently in use as remediation tools, either in
              the United States or in other countries  	6

Category B:   Electrokinetic processes which are in the experimental testing stage at bench, pilot,
              or field scale	29

Category C:   Electrokinetic processes which are currently in the conceptual development
              stage	73

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                                   LIST OF TABLES


                                                                                  Page

Table 1       Overview of in situ technologies for remediation of soils	5

Table 2       Category A Summary Table	7

Table 3       Effectiveness of electrokinetic treatment of gasoline in clay-composed soil .... 15

Table 4       Summary of Geokinetics International, Inc.'s various completed and ongoing
             remediation projects	22

Table 5       Category B Summary Table  	30

Table 6       Successfully completed or ongoing electrokinetic remediation projects carried
             out by Lynntech, Inc. since 1993  	58

Table 7       Category C Summary Table  	74
                                           in

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                                  LIST OF FIGURES
                                                                                  Page

Figure 1       Schematic diagram of a typical electrokinetic processing system	2
Figure 2       Lead concentration profile after 123 days of processing kaolinite sand mixture
              spiked at 5,322 mg/kg  	11
Figure 3       Confirmatory sampling location  	14
Figure 4       Diagrammatic overview of the Pool Process	19
Figure 5       Detail of electrode wells	20
Figure 6       Lagoon based remediation of dredgings  	20
Figure 7       Electrodes in place before power is applied	21
Figure 8       After remediation, electrodes removed	21
Figure 9       ELECTROSORB™ Cell	25
Figure 10      Installation of ELECTROSORB™ Cell	26
Figure 11      Isotron Electrode Array at Old TNX Basin	28
Figure 12      Example of an application for uranium decontamination using ELECTROSORB™
              cylinders	28
Figure 13      Major contributions of the participating Consortium members 	36
Figure 14      Layered horizontal and vertical configuration of the electrodes and degradation
              zones  	37
Figure 15      Metals removal at cathode 	42
Figure 16      Site map of DP-25 Sump Area	47
Figure 17      Site map of Area 27  	48
Figure 18      General arrangement of a demonstration using SEEC™ Pad technology  	51
Figure 19      Contaminant transport processes induced by applying direct current between
              buried electrodes 	52
Figure 20      Lynntech's Electrokinetic Field Technology  	57
Figure 21      Lynntech's Electrokinetic Field Technology  	57
Figure 22      Schematic of a field installation for in situ remediation by electro-osmotic
              purging	63
Figure 23      2-D multielectrode system 	63
Figure 24      Electrokinetic demonstration for chromate removal at the Unlined Chromate Acid
              Pit 	66
Figure 25      Aerial photo of electrokinetic site over the Unlined Chromic Acid Pit	67
Figure 26      Electrode array configuration for electrokinetic remediation of the Unlined
              Chromic Acid Pit	68
Figure 27      Electrokinetic remediation schematic 	69
Figure 28      Electrode effluent containing chromate contamination  	70

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INTRODUCTION AND SUMMARY

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The theory of applying electric current to the soil or groundwater for remediation of inorganic,
organic, radioactive and heavy metal wastes is called electrokinetic remediation. It is also known as
electroreclamation,  electrokinetic soil processing and electrochemical decontamination.  Figure 1
depicts a general illustration of an electrokinetic system.
   Figure 1: Schematic diagram of a typical electrokinetic processing system (Source: Electro
     Remediation Group, Ltd. and Lockheed Missiles and Space Co., Inc., Electrochemical
              Remediation of Contaminated Soil: A Technology Overview. 1993)
This figure shows a series of electrodes placed in the contaminated area. A small direct current (50-
150 volts) is then applied between the electrodes. Because of the charge on soil, water and the
contaminate, migration will occur towards the oppositely charged electrodes. In general,  active
electrodes in water cause an acid front at the anode and a base front at the cathode.  The pH will drop
at the anode and increase at the cathode. To prevent this pH imbalance, the electrodes are placed
inside ceramic casings which are filled with a processing fluid. This processing fluid (also called
surfactants and chelators) not only keeps a balance  of pH at the anode and cathode, if chosen
correctly, it also helps solubilize and move contaminants.  Some processing fluids which have been
used or considered are acetic acids, humic or gallic acids. The contaminant and processing fluid are
then taken through a pump and recycling purification system where the contaminate is removed and
the processing fluid is reused in the electrokinetic system.

There are five basic phenomena which together make up electrokinetic remediation. All have their

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own properties and  influences on the system but together work harmoniously to successfully
remediate a contaminated area. They are diffusion, electrolysis, eletroosmosis, eletrophoresis and
electromigration.  If the area of interest is considered to be undisturbed before the electric current is
applied, then the moment electricity enters the system diffusion begins. Diffusion is the process of
redistributing the matter which lies between the electrodes.  Electroosmosis is the movement of water
under the electric field.  This transport mechanism is necessary for contaminates to  move towards
electrode. The more saturated the soil, the easier electroosmois will occur.  Electrophoresis and
electromigration are the movement of soil particles and contaminates respectively under an electric
field.     Because of the negative charge on  soils, electrophoresis will be towards the anode.
Depending upon the  charge of the contaminate, electromigration can cause contaminate attraction
towards either the anode or the cathode.  Electrolysis is the chemical reaction which occurs around
the electrodes.  It can be properly manipulated with the appropriate chemical processing fluid as
previously described.

The concept of electrokinetic remediation has been theorized in the form of electroomosis since the
early 1800s. However, application of electrokinetic remediation to a contaminated  area is a fairly
innovative technology dating back to the early 1970s in the United States and in Europe.  In the
United States, the approach was led by engineering and civil engineering laboratories and academic
institutions. Technologically, the goal was to use electroosmosis to drive a flushing fluid between
opposing anodes and cathodes. U.S. development work was boosted by an Oregon meeting in 1986
called by the U. S. Environmental Protection Agency (EPA). European researchers, however, focused
on an entirely different approach. They used electromigration to desorb and then migrate anions and
cations to their respective electrodes.  Unlike the U.S. focus, much of the early European work was
undertaken by electrochemical researchers. The techniques which resulted showed this difference in
perspective.1

Some contaminates that have been tested with electrokinetic remediation have been uranyl, thorium,
radium, lead, cadmium, mercury, zinc, iron, magnesium, phenol, and BTEX compound (benzene,
toluene and ethylene). Electrokinetic remediation rivals innovative and standard technologies (like
soil excavation, incineration, vitrification, chemical stripping, phytoremediation, pressure flushing,
soil washing, solidification/stabilization, chemical oxidation, air-stripping and impoundment) because
of its efficacy of removal and its in situ and/or ex situ use.  However, a limitation to  this process is
that the contaminate needs to be solubilize either by an acid front or by a processing fluid in order for
the contaminate to be extracted. Table 1 provides an overview of the key factors for some of these
technologies including electrokinetics.

This document attempted to list and describe all published work on electrokinetic remediation from
1992 to 1997. This work includes electrokinetic remediation being used commercially or on a bench,
pilot, field or conceptual scale. There are three categories in this resource guide. The first category,
Category A, lists all electrokinetic processes that are used as the remediation tool at a contaminated
         Geokinetics, International, Inc., Electrokinetic Remediation of Toxic Metals: Statement of Qualifications , June
1997.

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site. Category B lists all electrokinetic processes that are being used on the bench, pilot or field scale.
Finally, Category C lists all electrokinetic process that are in the conceptual development stage.
Electrokinetic remediation being used abroad was also included in this resource guide. Information
about each electrokinetic system includes the developers' name and address, technical description,
status, cost and illustration (if available).  This document should be used as a resource guide to
understanding what work has been done in electrokinetic remediation as it applies to radioactive and
hazardous mixed wastes so further research in this area can progress.

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                                        Table 1
Overview of in situ technologies for remediation of soils (Source: U.S. Environmental Protection
   Agency, Office of Solid Waste and Emergency Response, In Situ Remediation Technology:
                      Electrokinetics. EPA542-K-94-007, April 1995)
TECHNOLOGY
Evaluation
Factor
Status
Range of
Metals Treated
Major Limiting
Factor(s)
Site-Specific
Considerations
Electrokinetics
Full-scale applications
in Europe
Recently licensed in
the United States
Broad
State-of-the-art
Moisture level of soil
Homogeneity of soil
Phytoremeditaion
Pilot-scale
Currently being
field-tested in the
United States and
Europe
Broad
State-of-the-art
Longer time required
for treatment
Crop yields and
growth patterns
Depth of
contamination
Concentration of
contamination
Soil Flushing
Commercial
Selected at a
number of
Superfund sites
Limited to
inorganics
(including
radioactive
contaminants)
Potential
contamination of
the aquifer from
residual flushing
solution
Permeability of
soil
Groundwater flow
and depth
Solidification/
Stabilization
Commercial
Broad
Concern with long-
term integrity
Debris
Depth of
contamination

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                             CATEGORY A

Electrokinetic processes which are currently in use as remediation tools, either
                 in the United States or in other countries

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         Table 2
Category A Summary Table
Name of
developer(s)



Electrokinetics,
Inc. (EK) —
CADEX™
electrode system

Environmental &
Technology
Services (ETS)








Isotron
Corporation —
ELECTROSORB™
Process



Soil
type(s)
tested


kaolinite




clay-
composed









mixture
of sand
and
kaolinite



Distance
between
electrodes


not
available



not
available









not
available





Depth the
electrodes
were
placed in

3 feet




not
available









not
available





Voltage
and/or
DC
current
level
not
available



10-15
amperes









not
available





Processing
fluid(s)



proprietary
conditionin
g agents


not
available









not
available





Size of
remediation
area


30 feet by 60
feet

Depth of 3
feet
200 feet by
200 feet

Depth of 70
feet






not available






Contaminant(s)
treated



lead




volatile organic
compounds
(VOCs), BTEX
(benzene,
toluene,
ethylbenzene,
xylene)
compounds,
total petroleum
hydrocarbons
(TPH)
uranium,
mercury





Time to
complete
cleanup


6-8 months




3-12
months









not
available





Contaminant
concentration
levels before and
after remediation

Before
1,000-5,000 ppm

After
not available
Before
VOC: 10-30 ppm
BTEX: 100-2,200
ppm
TPH: 3,000 ppm

After
VOC: < 0.1 ppm
BTEX: < 40 ppm
TPH: < 35 ppm

Before
mercury: 10-20
ppm

After
uranium: 50%-99%
removal
Treatment
cost



not
available



$17-$50
per ton









not
available






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    Table 2 (continued)
Category A Summary Table
Name of
developer(s)



Geokinetics
International, Inc.
(Gil) — Pool
Process










Soil
type(s)
tested


clay













Distance
between
electrodes


5-10 feet













Depth the
electrodes
were
placed in

0.3-3.3 feet













Voltage
and/or
DC
current
level
5-20
volts

0.5-1.0
amperes









Processing
fluid(s)



acid or alkali













Size of
remediation
area


230 feet by
10 feet

Depth of 3. 3
feet









Contaminant(s)
treated



arsenic,
cadmium,
chromium,
copper, lead,
nickel, zinc









Time to
complete
cleanup


2-18
months












Contaminant
concentration
levels before
and after
remediation
Before
Cd: 660 ppm
Cu: 500-1,000
ppm
Ni: 860 ppm
Pb: 300-5,000
ppm
Zn: 2,600 ppm
After
Cd: < 50 ppm
Cu: < 250 ppm
Ni: « 80 ppm
Pb: < 75 ppm
Zn: < 300 ppm
Treatment
cost



$300-$500*
per cubic
yard


*total cost









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41

Research:           CADEX™ electrode system2

Developer(s):        Electrokinetics, Inc. (EK)

Contact(s):          Dr. Robert Gale or Elif Ozsu-Acar
                     Electrokinetics, Inc.
                     11552 Cedar Park Avenue
                     Baton Rouge, LA 70809
                     Phone: (504) 753-8004
                     Fax: (504) 753-0028


Research Description

The project investigated the feasibility of removing lead from the soils (approximately 5,400 mg/kg)
in situ at Firing Range 24A located in Fort Polk, Louisiana (see Figure 2).  Bullets from the firing
operations disintegrated due to various environmental factors and resulted in the contamination of
the soil.  The site remediation project is being conducted for the U.S. Army Engineer Waterways
Experiment  Station  (USAEWES),   Vicksburg,  Mississippi,  and  operated  under  the  U.S.
Environmental Protection Agency's (EPA) Superfund Innovative Technology Evaluation (SITE)
Program. At the time of its initiation, this project represented the first comprehensive study in the
United States of the electrokinetic separation technology applied to in situ remediation of heavy
metals.

The principal compound for removal is lead which has accumulated at the site over a 30-year period.
The remediation site size is 30 feet by 60 feet and the soils are to be remediated to a depth of 3 feet.
The CADEX™ electrode system is being used to remediate the site. This electrode system controls
the chemistry at the cathode and enhances the removal of metal species. The  CADEX™ electrode
         Information provided was obtained from the following journals and reports:

Acar, Y.B. and Alshawabkeh, A.N., Principles of Electrokinetic Remediation, Environmental Science and Technology ,
       Vol. 27, No. 13, pp. 2638-2647 (1993)

Acar, Y.B., Gale R., Marks R.E., and Ugaz, A., Feasibility of Removing Uranium, Thorium, and Radium from Kalonite
       by Electrochemical Soil Processing, U.S. Environmental Protection Agency , No. 009-292, Electrokinetics, Inc.,
       LA (1992)

Electrokinetics, Inc., Technologies for Waste Management: Report on Project Descriptions

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995

                                             10

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system contains proprietary conditioning agents and a depolarizer that significantly reduces the input
power cost and needs only minimum maintenance during processing.
Status

In 1995, pilot-scale studies with 1.5 ton samples of a soil retrieved from the Army firing range and
contaminated with lead leached from bullets were  conducted.  As of June 1996, electrokinetic
remediation at the demonstration site was operated on a remote basis from a central control house
located at the site where DC input current, DC voltage, site resistivity, and pH can be measured.  The
demonstration site goal was to remove as much lead as possible from the soils between June and the
end of 1996. For detail information on this project, please contact:  Mr. Mark Bricka, Site Manager,
Waterway Experiment Station, 3909 Halls Ferry Road,  Vicksburg, MS 39180.  Phone: (601)
634-3700.
                                           11

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                          %
                           \
                            \
                                        Figure 2
 Lead concentration profile after 123 days of processing kaolinite sand mixture spiked at 5,322
mg/kg.  (Source: Electrokinetics, Inc., Technologies for Waste Management: Report on Project
                                     Descriptions)
                                          12

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A2

Research:           Electrokinetic Enhancement3

Developer(s):        Environmental & Technology Services (ETS)

Contact(s):          Dr. Walter W. Loo
                     Environmental & Technology Services
                     2081 15th Street
                     San Francisco, CA 94114
                     Telephone: (415) 861-0810
                     Fax: (415) 861-3269


Research Description

Research and case closure was completed in 1991 at a site in Anaheim, California.  The case involved
remediation of 150,000 tons of soil contaminated with chlorinated solvents. The volatile organic
compounds (VOCs) plume covered a 200 feet by 200 feet surface area. An electrokinetic electrode
system involving electro-osmosis desorption of chlorinated VOCs from a 10-foot thick wet clay-
composed  layer was installed.   Remediation  of  VOCs to less than 0.1 ppm was achieved.
Remediation cost was at about $17 per ton.  The closure was approved by the Santa Ana Regional
Water Quality Control Board and the Orange County Health Services in August 1991.

Another project conducted by ETS involved electrokinetic enhanced in-situ bioventing of gasoline
and BTEX (benzene, ethylbenzene, toluene, xylene)-contamination in soil. The gasoline in soil was
related to a 10,000-gallon underground storage tank spill in San Diego, California.  The gasoline soil
plume covered an area of about 2,400  square feet and to a depth of 30 feet with gasoline
concentration ranging from 100 to 2,200 ppm.  Direct current was applied through 56 electrodes
installed in the upper clay layer to  move the  contaminants  and water down  15 feet into dense
cemented conglomerate sandstone where contaminants were removed by bioventing. Electrolysis of
some water molecules, resulting from the electrical gradient, was thought to have produced hydroxyl
ions that promoted oxidation of the contaminants. Total petroleum hydrocarbons (TPH) and BTEX
were treated to non-detect in about 8 hours. The soil remediation effort was completed after about
90 days of treatment.  The concentration of gasoline in soil after treatment was less than 40 ppm. The
         Information provided was obtained from the following reports:

Loo, W.W. and Chilingar, G.V., Advances in the Electrokinetic Treatment of Hazardous Wastes in Soil and
       Groundwater, presented at HAZMACON 97, Santa Clara, California, pp. 1-15 (1997)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995

                                            13

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cost of treatment was about $50 per ton for this advanced soil treatment process which provides a
cost effective solution to this soil plume.

Another remediation effort in 1994 involved the removal of a 1,000-gallon underground storage tank
located at a warehouse and distribution facility in Los Angeles (see Figure 3).  The volume of the
gasoline soil plume was estimated to be about 3,300 cubic yards and the TPH concentrations were
as high as 23,000 ppm, with an average level of 3,000 ppm. The remedial system that was used
included a heat enhanced bioventing system, an ultraviolet light disinfection system, granular activated
carbon adsorption, and electrokinetic treatment which was designed to remediate the lower 5 feet,
35 to 40 feet below the surface grade, of low permeability clay-composed silts. The electrokinetic
system was connected to direct current (DC) power supply. The system was operated at about 10
to 15 amperes of electricity flow to 'dry out' the clay-composed  silts in the bottom 5 feet. After
approximately 12 months, samples taken from the site indicated that the concentration of TPH  as
gasoline in soil after treatment was below 35 ppm. The effectiveness of the electrokinetics treatment
of the clay-composed soil located at the 40-foot depth is given in Table 3.

Status

ETS is continuing to conduct research and remediation activities involving electrokinetic treatment
of hazardous and toxic waste in soil and groundwater. Several state-of-the-art remedial technologies
are being invented and implemented for use by Dr. Loo and ETS.
                                           14

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                                                     Figure 3
Confirmatory sampling location (Source: Loo, W.W. and Chilingar, G.V., Advances in the Electrokinetic Treatment of Hazardous
           Waste in Soil and Groundwater. presented atHAZMACON 97, Santa Clara, California, pp. 1-15, 1997)
                                                        15

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                                                      Table 3
                         Effectiveness of electrokinetic treatment of gasoline in clay-composed soil
(Source: Loo, W.W. and Chilingar, G.V., Advances in the Electrokinetic Treatment of Hazardous Waste in Soil and Groundwaten
                           presented atHAZMACON97, Santa Clara, California, pp. 1-15, 1997)

                                            (All units are in mg/kg or ppm)
                     Benzene
                 Toluene
                   Ethylbenzene
                       Xylene
                            Benzene
                          Toluene
                           Ethylbenzene
                                   Xylene
 C-l Area
 18
0.45
1.6
0.15
1.2
 2.9
  0.17
 0.6
0.03
  0.54
 C-2 Area

 C-5 Area
1300

 87
0.68

0.28
27

2.7
 23

 1.4
140
0.66

 1.7
No data

  0.07
0.18

0.43
0.06

0.04
No data

  0.51
                                                         16

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A3

Research:            Electrokinetic Remediation4

Developer(s):        Geokinetics International, Inc. (Gil)

Contact(s):           Dr. Stephen R. Clarke
                      Gil
                      829 Heinz Street
                      Berkeley, CA 94710
                      Telephone: (510) 704-2940
                      Fax: (510)848-1581
                      E-mail: EDASteve@aol.com


Research Description

Gil primarily uses an electrokinetic technology called the "Pool Process" (also called "closed loop
process") to remediate toxic heavy metals such as arsenic, chromium, nickel, copper, zinc, lead, and
cadmium (see Figure 4). The major components of the Pool Process are as follows:

       •      ion-permeable electrolyte casings are placed in the contaminated media and connected
              to a centralized electrochemical ion-exchange (EIX) based electrolyte management
              system.  Each casing has an electrode inside. Together, these form alternating rows
              of anodes and cathodes.  Electrolyte is circulated  in a closed loop between the
              electrode casings and the EIX units;

       •      electrolysis of water in  the electrolyte results in the formation of H+ ions at the
              anodes and OH- at the cathodes.  These ions migrate through the casing into the soil
              generating a temporary and localized pH shift which desorbs contaminating ions;
          Information provided was obtained from the Internet at the Geokinetics International, Inc. world wide web site
at http:\\www.geokinetics.com and the following reports:

Geokinetics, International, Inc., Electrokinetic Remediation of Toxic Metals: Statement of Qualifications , June 1997

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,  In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                              17

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       •      once desorbed, the contaminating ions migrate under the influence of the applied
              potential (electromigration) to their respective electrodes (anodes for anions, cathodes
              for cations). Here they pass through the electrode casing walls and are taken up by
              the circulating electrolytes.  The pH at the anode and cathode is managed by the
              addition of acid or alkali as required;

       •      contamination is selectively recovered from the circulating electrolytes as they pass
              through the EIX units.  Soluble but benign elements are returned to the soil to
              maintain soil properties;

       •      periodically the EIX units are regenerated by polarity  reversal.  This recovers the
              contaminants in a concentrated, pure and re-usable form.

Figure 5 shows some of the detail of the electrode wells. Figures 6, 7 and 8 show an example of an
actual  electrokinetic remediation of a lagoon of dredgings.  GIFs electrokinetic process can be
operated in three separate ways:

1)     In situ remediation: electrode wells  are placed directly in the ground and contamination is
       recovered with the slightest disturbance to the site.

2)     Batch operation:  contaminated media is transported to a batch facility and treated ex situ.
       Batch times  take between 1 to 5 days depending on electrode spacing and current loading.

3)     Electrokinetic Ring Fence (EKRF): this uses a chain of electrode pairs deployed in the ground
       to recover ionic contamination from groundwater as it flows past the electrodes.  It is
       significantly more efficient than pump and treat and is sludge free.

The first ever commercial application of electrokinetics was conducted in a former paint factory,
'Oeverbosch'  in  Groningen, the Netherlands, by  Gil in 1987.   The 400-cubic yard site was
contaminated with 20,000 ppm of lead and  12,000 ppm of copper.  A vertically installed array of
alternating anodes and cathodes (each consisting of an electrode placed inside a semipermeable well
casing) was spaced  on 10-feet intervals.  Anodes and cathodes were each connected to separate
anolyte and catholyte management systems.  Anolyte and catholyte pH was managed by the addition
of acid or alkali as  required.  The recirculating electrolytes were periodically treated to remove
collected contaminants and other ions. After 43 0 hours of operation, lead concentrations ranged from
90 to 700 ppm with an average reduction of 70 percent, while copper concentrations ranged from 15
to 250 ppm with an average reduction of 80 percent.
                                            18

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Another remediation project involving electrokinetics processing was conducted by Gil during 1992.
The proj ect was performed at Woensdrecht on behalf of the Dutch ministry of defense. The work
was undertaken at a former Dutch Royal Air Force base.  The 3400-cubic yard site was contaminated
with cadmium and other toxic heavy metals.  Aircraft wash-down operations  and  plating  shop
activities were the main reasons for the contamination. The recovered material was placed in a
temporary lagoon and treated in two large onsite batches.  Large horizontal tubular cathodes and
short vertical anodes were used. The cathodes were placed at 5-feet intervals at  the bottom of the
lagoon prior to it being filled with contaminated soil.  The tubular  anodes were placed at 5-feet
intervals  between the  cathodes after the lagoon was filled.  The electrokinetic process reduced
cadmium concentrations from 7,300 ppm to 47 ppm in 580 days. All other toxic metal concentrations
were also reduced significantly. This project is considered to be the largest electrokinetic project
completed worldwide.

Status

Gil continues to perform  several remediation projects involving electrokinetics both in the United
States and abroad. The commercial scale electrokinetic remediation technology used by Gil is mainly
used for the  extraction of toxic metals and toxic anions from  soil and groundwater.   Table 4
summarizes GIFs various completed and ongoing remediation projects.
                                            19

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                                   Figure 4
Diagrammatic overview of the Pool Process (Source: Geokinetics, International, Inc.,
 Electrokinetic Remediation of Toxic Metals: Statement of Qualifications. June 1997)
                                      20

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                    per
                       •.cable  ~\
                                             __ Lknliohh; fed & i-ciurn
                                         Figure 5
   Detail of a general electrode well (Source:  Geokinetics, International, Inc.. Electrokinetic
            Remediation of Toxic Metals: Statement of Qualifications. June 1997)
                                         Figure 6
Lagoon based remediation of dredgings (Source:  Geokinetics, International, Inc., Electrokinetic
            Remediation of Toxic Metals: Statement of Qualifications. June 1997)
                                            21

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                                       Figure 7
     Electrodes in place before power is applied (Source: Geokinetics, International, Inc.,
     Electrokinetic Remediation of Toxic Metals: Statement of Qualifications. June 1997)
                                       Figure 8
After remediation, electrodes removed (Source:  Geokinetics, International, Inc., Electrokinetic
           Remediation of Toxic Metals: Statement of Qualifications. June 1997)
                                        Table 4
                                          22

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   Summary of Geokinetics International, Inc.'s various completed and ongoing remediation
projects (Source:  Geokinetics International, Inc., Electrokinetic Remediation of Toxic Metals:
                         Statement of Qualifications. June 1997)
Year
1997-
ongoing
1997-
ongoing
1997-
ongoing
1997-
ongoing
1997
1996
1996
1996
1992 - 1994
Location
California
Virginia
Pearl Harbor -
Oahu, HI
Alameda Naval
Air Station
California
California
California
California
Temporary
Landfill at the
airbase of
Woensdrecht
Client
Large International
Chemicals Corporation
Large US Engineering &
Chemicals Corporation
US Navy & EPA Office of
Technology Development
US Navy & EPA Office of
Technology Development
Large international water
services company
EPA Region 6, Office of
Emergency Response
Large US Industrial &
Communications Company
EPRI & SoCal Eddison
Ministry of Defence/DGWT
Description
Pilot test of the recovery of Zn
from 80,000 yd3 chemical
sludge ponds
Large pilot scale evaluation of
Zn recovery from 200,000 yd3
chemical sludge ponds
In situ remediation of Pb from
battery re-processing plant
(1,500 yd3)
Pilot scale (40 yd3) recovery of
Cr from former plating
operations
Bench scale evaluation of Pb
recovery from former battery
plant
Bench scale evaluation of Zn
recovery from mine tailings
Bench scale recovery of Cr from
former plating shop
Large bench scale study and
conceptual design of Pb from
battery manufacturing site
Form on site lagoon and in situ
remediation of 3,400 yd3 sludge
contaminated with Cr, Ni, Cu,
Zn and Cd
Cost
Ongoing
Ongoing
Ongoing
Ongoing
$42,000
$45,000
$16,000
$75,000
$1,040,000
                                          23

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                                  Table 4 (continued)
   Summary of Geokinetics International, Inc.'s various completed and ongoing remediation
projects (Source:  Geokinetics International, Inc., Electrokinetic Remediation of Toxic Metals:
                         Statement of Qualifications. June 1997)
Year
1990 - 1992
1989
1988
1987
Location
Temporary Landfill
"Vleddermond" at
Stadskanaal
Former wood
impregnation plant
"PERDOK"
Loppersum
Galvanizing plant
"Braat" at Deflt
Former paint factory
"Oeverbosch" at
Groningen
Client
Municipality of
Stadskanaal/Province
of Groningen
Kwint
b.v./Municipality of
Loppersum
Bammensgroep,
Maarssen
Province of Groningen
Description
Establish temporary landfill
and in situ remediation of
2,500 yd3 soil and sludges
from gardens and canals at
Stadskanaal contaminated
withCd
In situ 300 yd3 clay polluted
with heavy metals Ar and
Cu
In situ 300 yd3 clay polluted
with heavy metals Zn and
Cd
In situ 400 yd3 clay polluted
with heavy metals Cu, Pb
andZn
Cost
$960,000
$160,000
$160,000
$120,000
                                          24

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A4

Research:           Electrokinetic Remediation5

Developer(s):        Isotron Corporation

Contact(s):          Henry Lomasney
                     Isotron Corporation
                     13152 Chef Menteur Hwy
                     New Orleans, LA 70129
                     Telephone: (504) 254-4624
                     Fax: (504)254-5172


Research Description

Electrokinetics was used in situ in 1994 in the Old TNX Basin at the Savannah River Site in South
Carolina to remediate mercuric nitrate contamination in unsaturated soil consisting primarily of sand
and kaolinite.  The ongoing project is supported by the U.S. Department of Energy's (DOE) Office
of Technology Development. An ELECTROSORB™ process with a patented cylinder (see Figures
9 and  10)  to control buffering conditions in situ and  an iron exchange polymer matrix called
ISOLOCK™ to trap metal ions were employed.

The electrodes are placed in boreholes in the soil and a direct current is  applied (see Figure 11).
Under the influence of the current, ions migrate through the pore water to an electrode, where they
are trapped in the polymer matrix.  If desired, the polymer can contain ion  exchange resins or other
sorbants that can trap and hold ions before they reach the electrode. When electric current is applied
to the system, electrodes are monitored and periodically replaced with fresh electrode assemblies.
This allows the used assemblies to be chemically treated and analyzed for  the presence of mercury
and other metals in the polymers and on the electrodes.  The special features of this technology are
         Information provided was obtained from the Internet at the Isotron Corporation world wide web site at
http:\\www.isotron.com and the following report:

Isotron Corporation, Electrolytic Migration Technology For Mercury Decontamination of Old TNX Area , Phase 1
       Technical Report, Subcontract No. AA89030P, July 1992

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                             25

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                                                 upply
                                               Scaling collar
                                               for clccErode &,
                                               sensor u
                                       Figure 9
ELECTRO SORB™ Cell (Source:  Isotron Corporation, Electrolytic Migration Technology For
   Mercury Decontamination of Old TNX Area. Phase 1 Technical Report, Subcontract No.
                                 AA89030P, July 1992)
                                          26

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                                Fotyvinyl Chloride
                                Tubing
                              LocMug collar KJ
                              position electrode
                              cyliadcr at desired
                              elevadbii
                                 Et£CTROSORB
                                 cylinder
                                        Figure 10
Installation of ELECTRO SORB™ Cell (Source: Isotron Corporation, Electrolytic Migration
  Technology For Mercury Decontamination of Old TNX Area. Phase 1 Technical Report,
                         Subcontract No. AA89030P, July 1992)
                                           27

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the polymer matrices that serve as ion traps. These matrices also serve as sources of chemicals that
can regulate pH or that will enhance the efficiency of the process. Preliminary investigations indicated
that mercury concentrations ranging from 10 to 20 ppm were found in the Basin.

Status

After the conclusion of the field  demonstration  at the Savannah  River  Site  in  1995, the
ELECTROSORB™ technology (see Figure 12) was also successfully used on a Unit 7 mine site in
Uzbekistan to decontaminate a 10,000 meter area contaminated with gamma emitting radionuclides
(uranium).  The gamma range was reduced from 50-99 percent in some areas after application of the
technology.
                                           28

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                                   r't
                                   Figure 11
Isotron Electrode Array at Old TNX Basin (Source: Isotron Corporation world wide web site at
                             http: \\www. i sotron. com)
                                             Anode OEmfer
                                   Figure 12
  Example of an application for uranium decontamination using ELECTROSORB™ cylinders
       (Source: Isotron Corporation world wide web site at httpAWww.isotron.com)
                                      29

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                            CATEGORY B
Electrokinetic processes which are currently in the experimental testing stage
                       at hpnrh. mint nr fiplH sralp
                 •/
at bench, pilot or field scale
                                   30

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         Table 5
Category B Summary Table
Name of
developer(s)



Consortium of
Monsanto, DuPont
and General
Electric —
Lasagna™ Process

Electrokinetics,
Inc. (EK) —
Electro-Klean™
Soil Processing













Soil
type(s)
tested


clay-
composed
with gravel
and sand
layers

saturated/
unsaturate
d sands,
silts, fine-
grained
clay,
sediments










Distance
between
electrodes


2-7 feet





3 feet
















Depth the
electrodes
were
placed in

15 feet





3 feet
















Voltage
and/or
DC
current
level
100-140
volts

40-45
amperes

450-600
volts

15-20
amperes












Processing
fluid(s)



not available





acetic acid
















Size of
remediation
area


15 feet by 10
feet

Depth of 15
feet

Lead
contaminated
site:

10 feet by 34
feet

Depth of 3
feet








Contaminant(s)
treated



TCE





uranium,
thorium, radium,
arsenic, BTEX
compounds,
cadmium,
chromium,
copper, lead,
nickel, phenol,
TCE, zinc








Time to
complete
cleanup


4-36
months




1-6 months
















Contaminant
concentration
levels before
and after
remediation
Before
1 ppb to 1760
ppm

After
< 1.5 ppm
Before
uranium:
1,000 pCi/g
thorium: 50-
300 pCi/g
radium: 1,000
pCi/g
lead: 2,000
ppm
After
uranium: 95%
removal
thorium,
radium: not
available
lead: 25%-
50% removal
Treatment
cost



$40-$90 per
cubic yard




$50-$150per
ton















           31

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    Table 5 (continued)
Category B Summary Table
Name of
developer(s)
Electro-Petroleum,
Inc. and Lehigh
University























Soil
type(s)
tested
kaolinite
clay, sand
























Distance
between
electrodes
not
available
























Depth the
electrodes
were
placed in
not
available
























Voltage
and/or
DC
current
level
30 volts

1.5
amperes






















Processing
fluid(s)
ethylenedi-
amine
(EDA),
distilled
water





















Size of
remediation
area
Laboratory
soil sample
tube 7.62 cm
long and
3.55 cm deep





















Contaminant(s)
treated
uranium,
strontium,
cesium,
chromium,
cobalt,
cadmium,
mercury, lead,
nickel, zinc,
hydrocarbons

















Time to
complete
cleanup
24-170
hours
























Contaminant
concentration
levels before
and after
remediation
Before
U: 10-100 ppm
Sr, Cs: 1,000
ppm
Cr: 3,000 ppm
Hg: 5-130 ppm
Ni: 1,000 ppm
Pb: 15,000 ppm
Zn: 22,500 ppm
After
U: 30%-80%
removal
Sr: 95%-100%
removal
Cs: 70%-90%
removal
Cr: 95%
removal
Hg: 60%-80%
removal
Ni: 94%
removal
Pb: 60%-85%
removal
Zn: 35%-65%
removal
Treatment
cost
$37.5 per
cubic yard
























    Table 5 (continued)
           32

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Category B Summary Table
Name of
developer(s)



Isotron
Corporation —
SEEC™ Pad
Technology and
ELECTROSORB™
Process

Lynntech, Inc.





Massachusetts
Institute of
Technology (MIT)









Soil type(s)
tested



sand,
kaolinite





low
permeability
soils (clay)



kaolinite











Distance
between
electrodes


4-5 feet






not
available




20
centimeter
s









Depth the
electrodes
were
placed in

2 feet






not
available




1.5
centimeter
s









Voltage
and/or
DC
current
level
90-100
volts

40-50
amperes


not
available




20 volts











Processing
fluid(s)



citrate and
carbonate
salts




not
available




acetic acid











Size of
remediation
area


8 feet by 9
feet

Depth of 2
feet


not available





Laboratory
sample
cylinder 200-
mm long and
32-mm in
diameter






Contaminant(s)
treated



uranium,
mercury





chromium, lead,
chlorinated
hydrocarbons



zinc, phenol











Time to
complete
cleanup


20-40
days





3-9
months




9-60 days











Contaminant
concentration
levels before
and after
remediation
Before
uranium: 600
ppm

After
uranium: > 99%
removal
Before
not available

After
lead: 65%
removal
Before
40% water +
500 mg/L zinc
60% kaolin clay

phenol: 45-450
ppm
After
zinc: 98%
removal
phenol: 94%
removal
Treatment
cost



$95 per ton






$65-$125 per
cubic yard




$20-$30 per
ton










           33

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    Table 5 (continued)
Category B Summary Table
Name of
developer(s)



Sandia National
Laboratories
(SNL)





Texas A&M
University





Soil type(s)
tested



unsaturated
soils with
25%
saturation




kaolinite,
saturated
silty clay




Distance
between
electrodes


not
available






5 meters






Depth the
electrodes
were
placed in

15 feet







5 meters






Voltage
and/or
DC
current
level
not
available






100 volts






Processing
fluid(s)



sodium
chloride






citric acid,
acetic acid,
disodium
ethylnedi-
aminetetr-
aacetate
(EDTA)
Size of
remediation
area


700 to 1,000
cubic feet
(depth of 15
feet)




50 meters by
100 meters

Depth of 5
meters


Contaminant(s)
treated



uranium,
chromium






copper, lead,
organics





Time to
complete
cleanup


4-12
months






6 months






Contaminant
concentration
levels before
and after
remediation
Before
chromium: 25-
10,000 ppm

After
chromium:
75%-90%
removal
Pb: 5,000 ppm
removal
Cu: 10,000 ppm
removal



Treatment
cost



$50-$150per
ton






$3 9 per unit
volume





           34

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Bl

Research:           Lasagna™ Process6

Developer(s):        Consortium  consisting of Monsanto, E.I.  du Pont de  Nemours & Co.
                     (DuPont), and General Electric (GE)

Contact(s):          Dr. Sa Ho
                     Environmental Services Center
                     Monsanto Company
                     St. Louis, MO 63167
                     Telephone: (314) 694-5179
                     Fax: (314)694-1531
                     E-mail: svho@monsanto.com


Research Description

In early 1994, EPA signed a Cooperative and Research and Development Agreement (CRADA) with
a private research Consortium — consisting of Monsanto, DuPont and GE — to jointly develop an
integrated, in situ remedial technology, referred to as the Lasagna™ process.  The Consortium's
activities are being facilitated by Clean Sites, Inc., under a Cooperative Agreement with EPA's
Technology Innovation Office.  The overall objective of the Consortium is to sufficiently develop the
integrated in situ remediation technology  so that it can be utilized for site remediation.  Figure 13
shows the major contributions of the participating Consortium members.

The Lasagna™  process remediates soils and soil pore water contaminated with soluble organic
compounds. Lasagna™ is especially suited to sites with low permeability soils where electro-osmosis
can move water faster and more uniformly than  hydraulic methods,  with  very low power
consumption.   The process uses electrokinetics  to move  contaminants in  soil pore water into
treatment zones where the contaminants can be captured  or decomposed.
         Information provided was obtained from the Internet at the Monsanto world wide web site at
http:\\www.monsanto.com and the following report:

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                            35

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Highly permeable subsurface sorption zones will be created in vertical configuration by hydraulic
fracturing or similar technology followed by the introduction of certain sorbants. The electrodes,
placed vertically on either side of contaminant plume, will flush contaminants by electro-osmotic flow
into sorption zones containing certain sorbants. (The electrodes may be constructed horizontally or
vertically depending on the site and contaminant characteristics.) The layered configuration of the
electrodes and degradation zones is shown in Figure 14. The contaminant targeted in this proposed
program is trichloroethylene (TCE).

The major features of the technology are:

       •      electrodes energized by direct current, which causes water and soluble contaminants
              to move into or through the treatment layers and also heats the soil;

       •      treatment zones containing reagents that compose the soluble organic contaminants
              or adsorb contaminants for immobilization or subsequent removal and disposal; and

       •      a water management system that recycles the water that accumulates at the cathode
              (high pH) back to the anode (low pH) for acid-base neutralization.  Alternatively,
              electrode polarity can be reversed periodically to reverse electro-osmotic flow and
              neutralize pH.

The major limitations to the Lasagna™ process are the following:

       •      treatment chemistry and procedures need to be developed to ensure compatibility of
              the treatment processes for individual contaminants;

       •      problems in maintaining  appropriate electrical contact to electrodes and trapping
              gases generated by electrolysis need to  be resolved; and

       •      for field implementation,  bioremediation in Lasagna™ treatment zones  need  to be
              further developed.

In early 1995, with significant funding by DOE, the work group initiated a field experiment  at the
DOE Paducah Gaseous Diffusion Plant (PGDP) in Kentucky, which has clay-composed soil
contaminated with TCE, to test the vertical configuration of the Lasagna™ process. The PGDP site
consists of a 4-foot layer of gravel and  clay overlaying a 40-foot  layer of sandy clay loam with
interbedded sand layers. The clay soil had been contaminated with TCE at concentrations ranging
                                            36

-------
                                  Dufont (Anaerobic BIcu
                                    VKrtif.it Zone liiaallation)
                    DOE (Site SelEdiun aril)
                     Field Support) C".  4,
                    Gaieral Etediiii, -„——
                    (EK an
                                                       CPA (Hydrafracturcr
   Integrated in-situ
Remediation Technology
                                          Figure 13
Major contributions of the participating Consortium members (Source: Monsanto world wide
                            web site at http:\\www.monsanto.com)
                                              37

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                                   A. Horizontal Configuration
                     «iPPLU-
                       POTC
                                                           u ai t ectrode
                                    B. Vertical Conflguraticn
                                        Figure 14
Layered horizontal and vertical configuration of the electrodes and degradation zones (Source:
                Monsanto world wide web site at httpAWww.monsanto.com)
                                           38

-------
from 1 ppb to 1,760 ppm. The average contamination at the PGDP site was 83.2 ppm. Due to low
organic content, the soil adsorbed very little TCE.
Status

Installation procedures of important elements of the field experiments in the vertical configuration
were conducted in the summer of 1994. CDM Federal Programs Corporation conducted preliminary
field tests, and in November 1994 they installed the field experiment at the DOE PGDP site. The
Phase I-Vertical field test, which operated for 120 days at the site, was successfully completed in May
1995.  Soil samples taken throughout the test site before and after the test indicate a 98-percent
removal of TCE, from a tight clay soil.  A Phase II-Vertical field experiment was planned at the
Paducah site for 1996. This phase is expected to consist of two stages.  In the first stage (Phase Ila-
Vertical), the Lasagna™ process will be used to treat 20 times more soil than Phase I. If successful,
this will  be followed by a  full-scale first  application  demonstration encompassing the entire
contaminated region (105 ft x 60 ft x 45-ft deep), with treatment to be completed in 12 to 24 months.
In addition, Phase I-Horizontal field tests in TCE-contaminated soils using the Lasagna™ process,
were to be conducted during the summer and fall of 1996 at sites in  Ohio and Nebraska, where
preliminary testing has already been conducted.

The technology implementation cost for Lasagna™ as conducted in the Phase I test (steel  plate
electrode with wick drains and carbon-filled treatment zone) is estimated at $80-$90 per cubic yard
for remediation in 1 year, $50-$60 per cubic yard if 3 years are allowed for remediation. Comparable
estimates for the Phase II mode of operation are $60-$70 per cubic yard (1 year) and $40-$50 per
cubic  yard (3  years).  Deeper contamination, although involving  more technically challenging
enhancement, costs less because of the larger volumes remediated per electrode.
                                           39

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B2

Research:            Electro-Klean™ Electrokinetic Soil Processing7

Developer(s):        Electrokinetics, Inc. (EK)

Contact(s):          Dr. Robert Gale or Elif Ozsu-Acar
                      Electrokinetics, Inc.
                      11552 Cedar Park Avenue
                      Baton Rouge, LA 70809
                      Phone: (504) 753-8004
                      Fax: (504) 753-0028


Research Description

Electro-Klean™ is a process that removes or captures heavy metals, radionuclides, and selected
volatile organic pollutants  from saturated or  unsaturated sands, silts,  fine-grained  clays,  and
sediments. Electro-Klean™ can be applied in-situ or ex-situ, and uses direct currents with electrodes
placed on each side of the contaminated soil mass.  Conditioning fluids may be added or circulated
at the electrodes to enhance the electrochemistry of the process. An acid front migrates towards the
negative electrode (cathode) and contaminants  are extracted through electroosmosis and electro-
migration (see Figure 15).  The concurrent mobility of the ions and pore fluid decontaminates the soil
mass.  Contaminants are electroplated on the  electrodes or separated in a post-treatment unit.
Bench scale tests have removed arsenic, benzene, cadmium, chromium, copper, ethylbenzene, lead,
nickel, phenol, trichloroethene,  toluene, xylene,  and zinc from soils. EPA has initiated the Volume
         Information provided was obtained from the following journals and reports:

Acar, Y.B. and Alshawabkeh, A.N., Principles of Electrokinetic Remediation, Environmental Science and Technology,
       Vol. 27, No. 13, pp. 2638-2647 (1993)

Acar, Y.B., Gale R., Marks R.E., and Ugaz, A., Feasibility of Removing Uranium, Thorium, and Radium from Kalonite
       by Electrochemical Soil Processing, U.S. Environmental Protection Agency , No. 009-292, Electrokinetics, Inc.,
       LA (1992)

Electrokinetics, Inc., Technologies for Waste Management: Report on Project Descriptions

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                              40

-------
Reduction and Chemical Extraction (VORCE) proj ect to investigate technologies that can reduce the
volume of soil contaminated with radioactivity at Superfund sites. The use of electrokinetics has been
included for investigation as a potential VORCE technology.

There  are however some limitations to the technology.  Some  of the major limitations to the
technology are that: 1) it is less cost-effective in sands and gravels for removal of VOCs as these
compounds are more easily removed by vacuum extraction, bioventing and soil washing techniques;
and 2) complex mixtures of heavy metals, radionuclides and organic pollutants  can affect the
electrochemistry and result in loss of removal efficiency.

Bench scale studies under EPA's SITE Program also demonstrated the feasibility of removing
uranium, thorium and radium from  kaolinite.  Uranium removal tests at 1,000 pCi/g of activity
demonstrated that the process efficiently removed uranium from kaolinite.  Removal efficiency
decreased from the anode towards the cathode, due to increase in pH. A yellow uranium hydroxide
precipitate was encountered in sections close to the cathode and on the cathode. Formation of this
precipitate  increases the resistivity,  the  voltage gradients and energy  expenditure.  Acetic acid
introduction at the cathode successfully prevented the precipitation encountered close to the cathode
and 95% of uranium removal was achieved.  Thorium removal tests at 50-300 pCi/g of activity have
demonstrated that thorium is only removed by migration from the leading anode sections of the cell.
Complex species that can reduce the net ionic charge on the thorium species are necessary in order
to efficiently remove thorium by electrokinetics.  Radium tests  at 1,000 pCi/g  of activity have
demonstrated minimal removal across the test cells. The only rational explanation is the extremely
low solubility  of the precipitated radium sulfate species.  Similar to the tests results for thorium,
complex species are necessary to remove radium.
Status

Theoretical and experimental modeling, bench scale, and pilot scale feasibility studies are routinely
performed in EK laboratories for an assessment of the potential to extract hazardous metals, organics
or radionuclides using in-situ electrokinetic remediation and/or in-situ electrokinetic bioremediation.

A pilot scale laboratory study investigating removal of 2,000//g/g lead loaded into kaolinite was
completed in 1993.  Removal efficiencies of 90 to 95 percent were obtained. The electrodes were
placed 3 feet apart in a 2-ton kaolinite specimen for 4 months, at an energy cost of about $ 15 per ton.
The results of a second pilot-scale laboratory study using 5,000 //g/g of lead absorbed on kaolinite
showed similar efficiency results as the earlier study.
                                            41

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In 1994, EK developed a mathematical model for multicomponent contaminant transport of reactive
species under an electric field. Three pilot scale tests were conducted using soil specimens weighing
1 ton in each test.  The objective of these tests was to investigate the effect of up-scaling bench scale
tests to pilot scale tests. These tests evaluated the feasibility and cost efficiency of electrokinetic soil
remediation at dimensions representing field conditions, and also assessed the hypothesized principles
of multicomponent contaminant transport under an electric field. Pilot scale tests demonstrated up
to 98 percent lead removal from soils. Also in 1994, EK, in collaboration with a Norwegian firm,
conducted bench  scale tests on samples retrieved from a site in Heimdal, Norway, to assess the
efficiency of removing chromium and to evaluate the efficiency of two different techniques proposed
for enhancement.  These tests were run for about 1200 to 1400 hours and, as a result, 68 percent of
the initial chromium present in the soil was removed. A pilot scale testing study in collaboration with
the Norwegian firm is currently in the planning stages.
                                            42

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                                      Figure 15
    Metals removal at cathode (Source: Acar, Y.B. and Alshawabkeh, A.N., Principles of
Electrokinetic Remediation. Environmental Science and Technology. Vol. 27, No. 13, pp. 2638-
                                    2647, 1993)
                                         43

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B3

Research:            In Situ Electrokinetic Soil Processing8

Developer(s):        Electro-Petroleum, Inc. and Lehigh University

Contact(s):           Dr. J. Kenneth Wittle
                      Electro-Petroleum, Inc.
                      Suite 1118
                      996 Old Eagle School Road
                      Wayne, PA 19087
                      Telephone: (610) 687-9070
                      Fax: (610) 964-8570


Research Description

Most of the research for the In Situ Electrokinetic Soil Processing has been conducted under two
contracts through the Argonne and  Sandia National Laboratories. Studies in the laboratory were
conducted jointly by Electro-Petroleum, Inc. and Lehigh University. The research was composed of
two phases of laboratory work.

In the first phase, short-term tests were carried out on the samples. The contaminant levels selected
in the experiments were typical of levels to be found at various  DOE sites.   The  laboratory
experiments have shown mobilization of 11 heavy metals and 6 organic compounds in 5 soil matrices.
The degree of success of decontamination seemed to be parameter specific and is more dependant
on the  type  of contaminant to  be removed  than the  type of medium being  decontaminated.
Researchers  determined that this electrokinetic process can treat soils,  sludges, and sediments
         Information provided was obtained from the following journals and reports:

Wittle, J.K. andPamukcu, S., Electrokinetic Treatment of Contaminated Soils, Sludges, and Lagoons. Final Report,
       DOE/CH-9206, U.S. Department of Energy, Argonne National Laboratory, (1993)

Wittle, J.K. andPamukcu, S., Electrokinetically Enhanced In-situ Soil Decontamination, in Wise and Trantolo (eds.)
       Remediation of Hazardous Waste Contaminated Soils, Chapter 13,  New York: Marcel Dekker, pp. 245-298
       (1993)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                             44

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contaminated with heavy metals (cadmium, mercury, lead, nickel, zinc), volatile and semi-VOCs,
solvents, BTEX compounds, surrogate radionuclides (cobalt, cesium, strontium, uranium) and
inorganic cyanides. It was determined, however, that the process works best on clay-composed soils
with low hydraulic permeability. Electrokinetic permeabilities for aqueous systems in clays have been
demonstrated to be up to one thousand times greater than normal hydraulic permeabilities, and some
heavy metals have exhibited removal efficiencies of up to 100 percent.

The second phase of work involved development of a model of contaminant transport in soils.
Testing of removal of soil contaminated with strontium and acetic acid was carried out. The model
predicted a slower rate of removal of strontium and a faster rate of removal for acetic acid than what
the laboratory tests demonstrated. In all the  electrokinetics  experiments, a constant 30-volts DC
potential was applied across the electrodes. The actual voltage gradient in soil varied in time and
space and also with type of soil contamination pair.
Status

The laboratory experiments demonstrated the capability to mobilize ionic and non-ionic contaminants
through various types of soil. The experiments also indicated that electrokinetics process has the
potential to solve soil remediation problems under a broad range of real site conditions. The process
can work well together with a surfactant flush, pump and treat system. Although reductions of up
to 100 percent have been demonstrated in the laboratory, field testing and treatability studies on site-
specific soil samples using electrokinetics processes are still under development.

A cost evaluation based on laboratory results and previous in-field investigations provided the basis
for estimating the treatment costs. For a 10,000-cubic yard site including equipment, power and
post-waste treatment, the cost is on the order of $37.5 per cubic yard.
                                           45

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B4

Research:            Electrokinetic Enhancement9

Developer(s):        Environmental & Technology Services (ETS)

Contact(s):           Dr. Walter W. Loo
                      Environmental & Technology Services
                      2081 15th Street
                      San Francisco, CA 94114
                      Telephone: (415) 861-0810
                      Fax: (415) 861-3269


Research Description

Several bench scale and field demonstrations of electrokinetic treatment were conducted on selenium,
boron, chlorinated solvents, and fuel hydrocarbons.  A description of the various research activities
is explained below.

In 1996 at the Panoche Water Drainage District (PWDD) in Firebaugh, California, ETS conducted
an in-situ electrokinetic treatment project. The objectives of the in-situ treatment were to:

       •      reduce the dissolved selenium in the PWDD drainage runoff water;

       •      reduce the dissolved boron in the PWDD drainage water to the extent possible that
              the water can be recycled for crop irrigation water uses; and

       •      reduce the dissolved solids in the PWDD drainage runoff water to the extent possible
              that the water can be recycled for crop irrigation water uses.
       Q
         Information provided was obtained from the following reports:

Loo, W.W. and Chilingar, G.V., Advances in the Electrokinetic Treatment of Hazardous Wastes in Soil and
       Groundwater, presented at HAZMACON 97, Santa Clara, California, pp. 1-15 (1997)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                              46

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The in-situ electrokinetic treatment systems were installed and conducted at DP-25 site and Area 27
of PWDD as represented in Figures 16 and 17.  ETS recommended that PWDD proceed with the
design of a drainage water quality management program by installing a network of electrokinetic
systems along the interceptor drain at DP-25.

Another research activity includes two case closures at a site located in Emeryville, California, with
the biodegradation of chlorinated solvents (TOX). In 1989, ETS successfully demonstrated the field
closure of the biodegradation of trichloroethene (TCE)  and trichloroethane (TCA) together with
toluene in soil through heat and nutrient enhancement by the growth of Bacilli and Pseudomonas
fluorescens.   In 1992 and  1993,  a TOX contaminated aquifer at  the site was  remediated by
electrokinetic enhanced in-situ passive cometabolic treatment.
Status

ETS is continuing to conduct research, field and remediation activities involving electrokinetic
treatment of hazardous and toxic wastes in soil and groundwater.  Several state-of-the-art remedial
technologies are being invented and implemented for use by Dr. Loo and ETS.
                                           47

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                                  '.'ATER TANK
                 RANOOHE WATER QRAIWAQe DFSTRSCT PROJECT
                                                      X
                                                       N
                                  Figure 16
Site map of DP-25 Sump Area (Source: Loo, W.W. and Chilingar, G.V., Advances in the
  Electrokinetic Treatment of Hazardous Wastes in Soil and Groundwaten presented at
              HAZMACON97, Santa Clara, California, pp.  1-15, 1997)
                                     48

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                                                   Figure 17
Site map of Area 27 (Source: Loo, W.W. and Chilingar, G.V., Advances in the Electrokinetic Treatment of Hazardous Waste and
                   Groundwater, presented at HAZMACON 97', Santa Clara, California, pp. 1-15, 1997)
                                                      49

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B5

Research:           Electrokinetic Extraction10

Developer(s):        Isotron Corporation

Contact(s):          Henry Lomasney
                     Isotron Corporation
                     13152 Chef Menteur Hwy
                     New Orleans, LA 70129
                     Telephone: (504) 254-4624
                     Fax: (504)254-5172


Research Description

The effectiveness of electrokinetics to move and capture uranium and organic contaminants in soil
was carried out in this demonstration project. The demonstration was supported by the U.S. DOE's
Office of Technology and Development. Isotron's concrete decontamination technology applies an
electric  field to induce migration of ionic contaminants from within the porous concrete into the
Isotron  decontamination unit.  The system utilizes the company's  patented ELECTROSORB™
process and SEEC™ pad technology (see Figure  18).  The electrolyte solution contains materials to
promote formation of a soluble ionic complex of each specific contaminant present.  The electrolyte
solution is in contact with the concrete surface through the carpet-like SEEC™ pad, which partially
removes contaminants from the electrolyte solution  and  limits the bulk flow of the  electrolyte
solution. All contaminants  are collected in the aqueous electrolyte solution which flows into the
separation module where the contaminants are removed. The contaminants are then collected in a
disposable cylinder or sorbent material.

The SEEC™ pad technology was used on a concrete structure at the K-25 building site in Oak Ridge,
Tennessee.  The project combines the use of selective extractants (citrate and carbonate salts) to
          Information provided was obtained from the Internet at the Isotron Corporation world wide web site at
http:\\www.isotron.com and the following reports:

Isotron Corporation, Electrokinetic Extraction of Uranium From K-25 Soil, Final Technical Brief', November 1995

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                             50

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remove the uranium with electrokinetics to transport the contaminants to ion exchange media. The
media surrounding the electrodes capture and concentrate the uranium for later recovery or disposal
(see Figure 19). The electrokinetics demonstration process was carried out at the K-25 site over an
area measuring 8 feet x 9 feet with an approximate volume of 144 cubic feet contaminated soil. The
depth of the uranium contamination at this site was approximately 2 feet.   An average uranium
concentration of 600 ppm was estimated. The demonstration area was covered with 6 SEEC™ pads
and the electrodes are buried at a depth of 2 feet with spacing 4.5 feet apart.  A 40-ampere current
is applied at a voltage gradient of 90 volts across the electrodes. The partial cost (not including labor
and excavation cost) for the field demonstration was $95 per ton of soil.
Status

Laboratory tests completed in 1994 using site soil showed that the process could move and capture
99 percent of the uranium.  A final treatability test report and a site characterization report was issued
in 1995 (see references).  Isotron is continuing to use its patented electrokinetic technologies to
remediate contaminated hazardous waste. Technological advances made by Russian scientists in this
area of environmental remediation are being used as much as possible in conjunction with Isotron's
own technology.
                                            51

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                    "Stet" Pad
                    (Typical)
 ___--
Vj
                                    A.Al
                                                 Detail A
                                                NA[i,i Pad
                                    Figure 18
General arrangement of a demonstration using SEEC™ Pad technology (Source: Isotron
Corporation, Electrokinetic Extraction of Uranium From K-25 Soil Final Technical Brief,
                                November 1995)
                                       52

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                              '' Electro-osmosis ' Electrophoresfe '
                                •OOK,OOO°O<>O/OOOOC
                                   \  .          /

                                      Figure 19
A general illustration of contaminant transport processes induced by applying direct current
     between buried electrodes (Source:  Isotron Corporation world wide web site at
                               http: \\www. i sotron. com)
                                          53

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B6

Research:           Electrokinetic Soil Processing11

Developer(s):        Lehigh University

Contact(s):          Dr. Sibel Pamukcu
                     Lehigh University
                     Department of Civil and Environmental Engineering
                     Fritz Engineering Laboratory
                     13 East Packer Ave.
                     Bethlehem, PA 18015
                     Telephone: (610) 758-3220
                     Fax: (610) 758-4522
                     E-mail: sp01@lehigh.edu


Research Description

The critical parameters of electroosmosis and flow enhancing ions have been investigated in a series
of laboratory experiments.  Laboratory tests on soil contents collected from a former manufactured
gas plant (MGP) site indicate that electrokinetic processes can assist in the transport and removal of
coal tar constituents from contaminated soils.

From 1992 to 1993, investigators conducted long-term electrokinetic tests on soil cores collected
from  a former MGP site.   Some  of the tests were enhanced  by injecting solubilizing agents
(surfactants) into the soil. Researchers subjected samples to varying levels of water flow, depending
on the physical properties of the soil, for a period of 3 to 4 weeks.  During each test, they monitored
the systems for voltage,  current, and in-flow and out-flow of liquid through the soil. After each test,
they analyzed soil specimens for polynuclear aromatic hydrocarbon (PAH) concentration profiles and
pH profiles to determine the extent of PAH transport  and removal.
         Information provided was obtained from the following reports:

Pamukcu, S., Electrokinetic Removal of Coal Tar Constituents from Contaminated Soils , Electric Power Research
       Institute Report, EPRI-TR-103320, Palo Alto, CA, p 32 (1994)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,  In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                             54

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The study demonstrated successful removal of 16 targeted PAH compounds from the soil (clay or
granular) at a removal rate of 44 to 70 percent upon 2 to 9 pore-volumes of electro-osmotic water
flow through the soil specimens.   In  general,  the  degree of success  of  decontamination by
electrokinetic processes appeared  to be parameter specific; more dependent on the type of the
contaminant to be removed than the type of medium being contaminated.  Electroosmosis appeared
to be the dominant mechanism of transport when the contaminants present in the aqueous phase were
nonpolar or nonionic, neutral micelles or surface-coated colloids.

Investigations of clay or clay mixtures and a known concentration of a selected heavy metal salt
solution or an organic compound  (such as sodium dodecylbenzene sulfonate) showed up to 99
percent heavy metal removal, and high removals of some organic compounds such as phenol, acetic
acid, and O-nitrophenol. In addition, removal of radionuclides was also achieved.  A cost evaluation
based on laboratory results and previous in-field investigations provided the basis for estimating the
treatment costs. For a 10,000 cubic yard site including equipment, power and post-waste treatment,
the cost is on the order of $37.5 per cubic yard.
Status

Further research  and development of this  method  is being  conducted to determine if the
electrokinetics process can be used on  a field scale to provide a reliable  method  for in-situ
remediation of MGP sites.
                                           55

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B7

Research:           Electrokinetic Remediation12

Developer(s):        Lynntech, Inc.

Contact(s):          Dr. Tom Rogers or Dr. Dalibor Hodko
                     Lynntech, Inc.
                     7610 Eastmark Drive, Suite 105
                     College Station, TX 77840
                     Telephone: (409) 693-0017
                     Fax: (409) 764-7479


Research Description

Researchers at Lynntech have studied methods to combine electrokinetics and bioremediation, an
effective low environmental impact treatment process, for in situ degradation of a wide range of
organic pollutants. Bioremediation has two major disadvantages: 1) slow rate of action; and 2) its
adverse effect on low permeability soil (such as clay).  Electrokinetic process can overcome these
disadvantages by:

       •      enabling movement and delivery of essential nutrients to the anaerobes; and

       •      uniform delivery  of nutrients in low permeability soils

Although this method is in its early stage of development, there is an enormous commercial potential
for this technology because of its low cost of implementation.

Lynntech has also successfully completed a 3-month field demonstration test for removal of heavy
metals from soil at Radford Army Ammunition Plant in Radford, VA. During this test, more than 65
percent of lead contamination was removed. The method does  not involve excavation or offsite
transportation, does not create any environmental impact and is  a favorable approach in terms of
public perception.
         Information provided was obtained from the following report:

Hodko, D. and Rogers, T.D., Lynntech, Inc. Electrokinetics Technology Capabilities Brochure , August, 1997
                                            56

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The treatment costs, based on actual field experience range from $65-$ 125 per cubic yard of treated
soil.  The Lynntech field technology (see Figures 20 and 21) is fully automated and once installed,
can be operated and monitored remotely, thus minimizing process and project cost.
Status

Lynntech is at present conducting a field demonstration in Florida at the Kennedy Space Center to
practically apply the combinational bioremediation-electrokinetic process based on laboratory tests.
This project is being conducted for the National Aeronautics and Space Administration (NASA)
under the Small Business Innovative Research (SBIR) program. A summary of Lynntech's completed
and ongoing electrokinetic projects is listed in Table 6.
                                           57

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                                     Figure 20
Lynntech's Electrokinetic Field Technology (Source: Lynntech, Inc. capabilities brochure)
                                     Figure 21
Lynntech's Electrokinetic Field Technology (Source: Lynntech, Inc. capabilities brochure)
                                         58

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                                        Table 6
Successfully completed or on-going electrokinetic remediation projects carried out by Lynntech
                 since 1993 (Source:  Lynntech, Inc. capabilities brochure)
Project Title
Pulsed DC Electric Fields for Heavy
Metals Decontamination of Soil
Pulsed DC Electric Fields for Heavy
Metals Decontamination of Soil
- Field demonstrated in 1995
Dielectrophoresis: Application to
Polluted Soil Remediation
In Situ Degradation of Dioxins by
Chemical Oxidation
In Situ Degradation of Dioxins by
Chemical Oxidation
- Field demonstrated in 1997
Engineered Bioremediation of
Contaminated Soil Through
Enhancement of Microbial
Populations
Engineered Bioremediation of
Contaminated Soil Through
Enhancement of Microbial
Populations
- 9-month field demonstration in
progress at Kennedy Space Center
New Electrochemical Process for In
Situ Soil Decontamination
A Micromodel Study of Residual
Hydrocarbon Mass Transfer Rates in
Porous Media
Client
DOD: $50K
9/92 - 3/93
DOD: $683K
9/92 -12/95
NSF: $65K
1/94 - 8/94
DOD (Air Force):
$58K
5/94-11/94
DOD (Air Force):
$705K
5/95 - 5/97
NASA: $70K
11/94-5/95
NASA: $539K
3/96 - 3/98
NSF: $65K
1/95 - 6/95
DOD (Air Force):
$80K
7/95 - 1/96
Accomplishment
One of the first demonstrations of the value of non-
uniform electric fields in electrokinetics
Successful field implementation of electrokinetic
for metal recovery. Significant developments
made in process design and control
Implemented new electric field effects with unique
applications to nonmetallic contaminants
Laboratory demonstration of a combined
electrokinetic/soil oxidation system
At the time of its initiation, the first field scale
implementation of electrokinetics for chemical
oxidant delivery. Made substantial improvements
in field hardware and installation procedures
A laboratory system demonstrating the use of
electrokinetic soil processing to enhance
bioremediation
Field demonstration of electrokinetics to control
soil redox chemistry to promote anaerobic
biodegradation of chlorinated solvents.
Advancements in electrode well designs made
Novel cathode designs were investigated as a
unique method to control the redox chemistry
surrounding the electrodes
Development of a unique understanding of the
effects of electrokinetics at the microscopic level
                                           59

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                                      Table 6 (continued)
Successfully completed or on-going electrokinetic remediation projects carried out by Lynntech
                   since 1993 (Source:  Lynntech, Inc. capabilities brochure)
         Project Title
   Client
             Accomplishment
Transport of Colloidal Size Particles
Through Porous Media: A New
Approach for Formation of
Impermeable and Reactive
Subsurface Barriers
  NSF: $70K
  1/97-6/97
The first laboratory demonstration of electrokinetic
technology for in situ barrier emplacement
Soil Treatability Study Remedial
Services: Camp Stanley Storage
Activity Area
- Field demonstration in progress
   Parsons
 Engineering:
   $73.5K
  4/96 - 9/96
An ongoing field demonstration of the use of non-
uniform electric fields at a site contaminated with
chromium
Electrokinetic Demonstration:
NAWS Point Magu, CA
- 9-month field demonstration
planned at 2 test sites in 1998
LB&M Assoc.,
 Inc.: $756K
 8/97-11/98
Remediation of chromium in a tidal marsh area
                                              60

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B7

Research:            Electroremediation13

Developer(s):        Massachusetts Institute of Technology (MIT)

Contact(s):          Dr. Ronald F. Probstein
                      MIT Department of Mechanical Engineering
                      77 Massachusetts Avenue
                      Cambridge, MA 02139
                      Telephone: (617) 253-2240
                      Fax: (617) 258-8559
                      E-mail: rfprobst@mit.edu


Research Description

MIT researchers used laboratory experiments and mathematical modeling to study the changes in the
flows of ions and pore liquid during the removal of contaminants from soils using electric fields.  The
flows are directly related to the removal of charged and uncharged contaminants by electromigration
and electroosmosis, respectively. The laboratory experiments consist of purging a prepared kaolinite
sample which is loaded with a known amount of phenol or acetic acid.

The process of electro-osmotic purging uses  an  electric field that is applied to soils which are
saturated  or partially saturated with contaminated water (see Figure 22).  The applied electric field
moves the water and dissolved contaminants to the electrode wells where they may be pumped to the
          Information provided was obtained from the following journals and reports:

Jacobs, R.A. and Probstein, R.F., Two-Dimensional Modeling of Electroremediation, AIChEJ. 42, pp. 1685-1696 (1996)

Jacobs, R.A., Sengun, M.Z., Hicks, R.E., and Probstein, R.F., Model and Experiments on Soil Remediation by Electric
       Fields, J. Em. Sci & Health, 29A , No.9 (1994)

Probstein, R.F. and Hicks, R.E., Removal of Contaminants from Soils by Electric Fields , Science 260, pp. 498-503 (1993)

Probstein, R.F. and Shapiro, A.P., Removal of Contaminants from Saturated Clay by Electroosmosis , Env. Sci. &
       Technology 27, pp. 283-291 (1993)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                              61

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surface. A nontoxic purge solution that is drawn in at one of the electrodes is used to wash the soil
and to prevent the formation of cracks by maintaining soil saturation.  The solution may contain
reagents to enhance the mobility of contaminants that are not originally present in the aqueous phase.
ADC power connected to the carbon electrodes - 1.5 centimeters deep and placed 20 centimeters
apart — was controlled to maintain a constant voltage of 20 volts across the clay. The process is
shown to be very effective at removing organics such as phenol and acetic acid from clay, achieving
at least 94 percent removal under certain conditions, and has also shown 98 percent removal of heavy
metals such  as zinc.

The factors which determine the success of the decontamination are the combined effects of electro-
osmotic convection, ionic migration, chemical equilibria, and electrochemical reactions.  These
phenomena  are analyzed in a model which compares favorably with experiments.   The one-
dimensional  mathematical model takes into account the complex interaction of subsurface effects that
occur  simultaneously  when a direct current is applied in soil.   The model can also describe
complexation, dissolution and precipitation reactions, surface complexation and sorption processes,
and  electrochemical reactions.   Both the  experiments and  the  mathematical model show the
development of sharp fronts, some propagating with the electro-osmotic flow and others stationary
at the electrodes.   The pH  of the purging solution is shown  to have significant  influence on the
electro-osmotic velocity and can be selected to optimize the process.
Status

MIT has been conducting research on electroremediation for the past 10 years. This research, which
is  sponsored by DOE, is  expected to  improve the efficiency and reduce the cost of practical
applications of the technology. It is expected that the model developed will provide an important
guide to laboratory and pilot-scale treatability studies.

Recently, researchers at MIT have developed a two-dimensional model and numerical code for the
simulation of contaminant removal from soils by electric fields. Like the one-dimensional model, this
model also describes the coupled transport of mass and charge, and the chemical speciation of a
multicomponent system subjected to an electric field. The two-dimensional model was developed to
address the variation of the current density with the geometry of the electrode array.  The computer
code developed for the two-dimensional model, computes the time evolution of several state variables
(including the spatial distributions of the electrostatic potential and pressure, the current density, and
all species velocities and concentrations) in  a multielectrode, multicomponent system of arbitrary
shape subject to an electric field (see Figure 23).  The results from this model can be applied to three-
dimensional systems in which the distance between electrodes is small compared to their length, and
there is  no significant variation of the material properties with depth.
                                            62

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Laboratory experiments applying DC electric fields to soils containing aqueous solutions of soluble
contaminants show potential for an effective in situ means for cleaning waste sites. Limited field tests
and computer modeling support this projection, although the ability to make quantitative predictions
of expected contaminant removal and costs at an actual hazardous waste site is at an early stage.
Several development steps are needed to  assess this method's potential:  the results of well
characterized field tests together with additional laboratory data, particularly on the removal of heavy
metals and their interactions with different soils of varying degrees of saturation; reagents  for
enhancing the desorption and solubilization of both organic and inorganic contaminants; and
improved predictive models that enable optimization of the process variables. MIT researchers are
at present carrying out a field test in New Jersey on a chromate contaminated  site under EPA
auspices, but the test is essentially just starting and no results are available as yet.

Laboratory experiments on organics removal by electroosmosis purging at moderate voltages, so that
heating losses are not excessive, show energy costs averaging about 20kWh per cubic meter of
effluent. The estimated energy costs for contaminant removal by  electric fields based on  the
experiments, could approximate $20 to $30 per ton.
                                            63

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                                    Figure 22
Schematic of a field installation for in situ remediation by electro-osmotic purging (Source:
   Probstein, R.F. and Shapiro, A.P., Removal of Contaminants from Saturated Clay by
            Electroosmosis. Env.  Sci. & Technology 27, pp. 283-291, 1993)
                                    Figure 23
 2-D multielectrode system (Source: Jacobs, R.A. and Probstein, R.F., Two-Dimensional
          Modeling of Electroremediation. AIChE J. 42, pp. 1685-1696, 1996)
                                       64

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B8

Research:           In Situ Electrokinetic Extraction System14

Developer(s):        Sandia National Laboratories (SNL)

Contact(s):          Eric R. Lindgren
                     Sandia National Laboratory
                     P.O. Box 5800, Mail Stop 0727
                     Albuquerque, NM 87185
                     Telephone: (505) 844-3820
                     Fax: (505) 844-1480
                     E-mail: ERLINDG@sandia.gov


Research Description

The purpose of this  research is to develop an in situ  electrokinetic process for remediating
unsaturated  soils (as low as about 25 percent saturation) contaminated with anionic (negatively
charged) heavy metals (such as chromium and radionuclides) without raising soil moisture content
significantly. In sandy soils with approximately 40 to 60 percent moisture saturation, the bench scale
electrokinetic process removed 75 to 90 percent chromium. Chromium contamination is of interest
because it is one of the most significant contaminants in the SNL Chemical Waste Landfill (CWL)
Unlined Chromic Acid Pit (UCAP) (see Figures 24 and 25). At the CWL, electrokinetics has been
used to remove negatively charged chromium ions from the chromate plume in the vadose zone below
the UCAP.  Chromium contamination has been detected to a depth of 75 feet at the CWL.

Three to five electrode pairs, supplied with water and neutralization chemicals, were used to treat
chromium-contaminated soil over a 120-day period. Between 25 and 120 kilograms of chromium
was removed from 700 to 1,000 cubic feet of soil. Soluble chromium concentrations range from 25
(background) to 10,000 ppm with the upper limit at 15 feet below ground surface.  Contaminants
arriving at the electrode were removed using a vacuum system. To use the electrokinetic system,
electrodes are installed in the ground in a square array and connected to a DC voltage power supply
         Information provided was obtained from the Internet at the Sandia National Laboratory world wide web site at
http:\\www.sandia.gov and the following report:

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
                                            65

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(see Figures 26 and 27).  Each electrode assembly contains water, a pump, an  electrode, and
numerous sensors and controllers.  The outer casings of the electrodes are made of porous ceramic
which allows electrical current and contaminants to pass.  A vacuum is applied to the casings which
keeps the water inside the assembly from flowing out and saturating neighboring soils.  The
electrodes are placed in the predetermined treatment zone with the ceramic casing at the treatment
depth of 15 feet below ground surface. When the DC power supply is applied to the soil between
electrodes, water flows in the soil pores (usually towards the cathode). The SNL electrode design,
however, allows water to enter the soil  at the anode, supplying  the pore water adjacent to the
electrode casing but never saturating the soil. The ions are then pumped to the  surface by circulating
water within the ceramic casing. Electrode effluent containing chromate contamination is shown in
Figure 28.

A major advantage of this particular electrokinetic system is that it operates in unsaturated soil for
much longer periods of time than  if simple electrodes were used.  In addition, the process needs
relatively limited amounts of energy compared to excavation: a 40K watt portable diesel generator
can power the system.  A major limitation to this process is that  buried metal objects divert the
current from the soil needing remediation.  Another problem can arise if large amounts of nontargeted
contaminants are present in the soil to be treated. Estimates for electrokinetic remediation range from
$50 to $150 per ton.  Processes involving excavation of soil cost $200 to $500 per ton.
Status

Research and demonstrations at SNL are supported by DOE. The technology was developed and
tested at the bench and pilot scale in 1993.  In 1994, a prototype electrode system was field-tested
in the UCAP, inside the CWL, to characterize the process and to demonstrate in situ water control
in unsaturated soil. Efforts are underway to extend the technology to treat cationic contaminants
which adsorb strongly to soil or exist as solid precipitates. Organic complexants are electrokinetically
injected into the soil at the cathode and form anionic complexes with certain contaminants which are
attracted to and removed from the anodes.  The SNL In Situ Electrokinetic Extraction System was
also demonstrated at SNLs UCAP from May 15 to November 24,1996, and evaluated under the EPA
SITE Program.  The target contaminant for the demonstration was hexavalent chromium in the form
of chromate ions. SNL researchers indicate that this process can also be used for uranium removal
at DOE's Hanford site.  Commercial availability of the technology is expected in 1998.
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                                     Figure 24
Electrokinetic demonstration for chromate removal at the Unlined Chromate Acid Pit (Sandia
 National Laboratories, Tech Area III, Chemical Waste Landfill) (Source:  Sandia National
               Laboratory world wide web site at http:\\www.sandia.gov)
                                         67

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                                      Figure 25
   Aerial photo of electrokinetic site over the Unlined Chromic Acid Pit (Sandia National
Laboratories, Tech Area III, Chemical Waste Landfill) (Source:  Sandia National Laboratory
                     world wide web site at http:\\www.sandia.gov)
                                         68

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                                     Figure 26
Electrode array configuration for electrokinetic remediation of the Unlined Chromic Acid Pit
   (Source: Sandia National Laboratory world wide web site at httpAWww.sandia.gov)
                                         69

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                                        Electrophoresis
                                        inouemoit of palOclcs
                                          Figure 27
Electrokinetic remediation schematic (Source:  Sandia National Laboratory world wide web site
                                  at http: \\www. sandia.gov)
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                                       Figure 28
Electrode effluent containing chromate contamination (Sandia National Laboratories, Tech Area
   III, Chemical Waste Landfill) (Source:  Sandia National Laboratory world wide web site at
                                 http: \\www. sandia.gov)
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B9

Research:            Electrokinetic Extraction15

Developer(s):        Texas A&M University

Contact(s):           Dr. Albert T. Yueng
                      Texas A&M Department of Civil Engineering
                      College Station, TX 77843-3136
                      Telephone: (409) 845-6554
                      Fax:  (409) 845-6554
                      E-mail: alyeung@tamu.edu


Research Description

Basic electrokinetic phenomena in  clay and the fundamental contaminant removal mechanisms by
electrokinetics was studied  by researchers. The research was conducted for the U.S. Army Corps
of Engineers (USAGE) Waterways Experiment Station under the Installation Restoration Research
Program. The research was funded in part with  federal funds as part of the program of the Gulf
Coast Hazardous Substance Research Center which is supported by the EPA, and in part with funds
from the State of Texas as part of the program of the Texas Hazardous Waste Research Center.

A coupled flow theory for the transport of fluid, electricity,  and chemical gradients to describe the
contaminant transport during the electrokinetic extraction process was formulated. Electrochemical
reactions associated with the processes  and soil-contaminant interactions are also  included.  A
numerical model was developed to simulate the contaminant transport, electrochemical reactions, and
          Information provided was obtained from the following journals and reports:

Alshawabkeh, A.N. and Yueng, A.T., Practical Aspects of In-situ Electrokinetic Extraction, submitted to the Practice
       Periodical of Hazardous, Toxic, and Radioactive Waste Management  of ASCE for review and possible
       publication on April 29, 1997

Datla, S. and Yeung, A.T., Subsurface Migration of Contaminants under the Coupled Influences of Hydraulic, Electrical,
       and Chemical Gradients, Proceedings of the 8 * International Conference of the International Association of
       Computer Methods and Advances in Geomechanics , Morgantown, West Virginia, pp. 1042-1048 (1994)

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
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soil-contaminant interactions during the extraction processes.  Bench scale experiments on the
cleanup of contaminants - such as sodium chloride, lead nitrate, phenol, and acetic acid - from
Milwhite kaolinite (a commercial product from Patria Packaging, Inc., Valdosta, Georgia) were
performed to evaluate the validity of the theory and numerical model.  The results obtained from the
extraction of lead from Milwhite kaolinite (using disodium ethylnediaminetetraacetate (EDTA) as an
enhancement agent) show that the removal of contaminants started towards the end of the  samples
and slowly migrated inwards.  Low pH conditions developed at the anode and high pH conditions
developed at the cathode. The research shows that the validity of the theoretical model is supported
by experimentally measured results, but there is need to develop guidelines and to optimize operation
parameters for the electrokinetics process.
Status

In the laboratory experiments, an example of a contaminated area of 50 meters x 100 meters was
considered.  The depth of contamination was assumed to be 5 meters and the soil is saturated silty
clay. Remediation time is assumed to be 6 months. The electrodes were placed 5.2 meters apart and
the electric voltage across opposite electrodes was 100 volts. The total costs per unit volume based
on these parameters was determined to be $38.5.  The viability of the research undertaken on
electrokinetics extraction, an emerging in-situ technology, is being continued to be established by
many bench-scale and large-scale experiments, and pilot-scale field investigations, but is not in use
as a remediation tool.  Some important practical aspects such as a cost analysis and design criteria
need to be considered before the technology can be successfully implemented in the field.
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                          CATEGORY C

Electrokinetic processes which are currently in the conceptual development
                               stage
                                74

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                                                       Table 7
                                              Category C Summary Table
Name of
developer(s)



University of
Massachusetts at
Lowell

West Virginia
University

Soil
type(s)
tested


kaolinite
and fine-
grained
soils
fine-
grained
soil
Distance
between
electrodes


not
available


not
available

Depth the
electrodes
were
placed in

not
available


not
available

Voltage
and/or
DC
current
level
not
available


not
available

Processing
fluid(s)



natural and
synthetic
flushing
solutions
not available


Size of
remediation
area


not available



not available


Contaminant(s)
treated



lead, benzene,
toluene, m-
xylene, TCE

lead


Time to
complete
cleanup


not
available


not
available

Contaminant
concentration
levels


not available



not available


Treatment
cost



not available



not available


Cl
                                                        75

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Research:           Electrokinetics16

Developer(s):        University of Massachusetts at Lowell

Contact(s):          Dr. Clifford Bruell
                     University of Massachusetts at Lowell
                     Civil Environmental Department
                     One University Avenue
                     Lowell, MA 01854
                     Telephone: (508) 934-2280
                     Fax:  (508) 934-3052


Research Description

Since 1992, researchers have been conducting laboratory studies on the effectiveness of
electroosmosis for removing hydrocarbons and heavy metals from clay.  Benzene, toluene, TCE
and m-xylene — all of which have relatively high water solubilities — were more easily removed
from fine-grained soils than hexane and isooctane and other compounds with low water
solubilities and high distribution coefficients.  Researchers also are studying the physical and
chemical characteristics of electro-osmotic contaminant transport.  The data are being used to
gain insights into electro-osmotic organic contaminant displacement and how soil and pore water
characteristics affect the process.

Status

In 1996, additional laboratory experiments for the use of electrokinetics in combination with
natural and synthetic flushing solutions  were studied to determine their efficiency in removing lead
from clay.  Natural flushing solutions were prepared by mixing water and clay in varying ratios by
weight. An ideal ratio was determined through a comparison of lead removal efficiencies. The
          Information provided was obtained from the following reports:

Bruell, C.J., Coletta, T.F., Inyang, H.I., and Ryan, D.K., Electrokinetics and Ionic Solutions to Remove Lead from Kaolin
       Clay, presented at the 3rd International Symposium on Environmental Geotechnology, June 10-12, 1996

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
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primary elemental constituents of the natural solution were then determined. A synthetic solution
with varying concentrations of aluminum and calcium was made and compared to the natural
solution for lead removal efficiency.  The synthetic solutions of aluminum and calcium with the
highest efficiency were then compared.  In the final analysis, it was determined that the
concentrations of the elemental constituents of the flushing solution complemented the
electrokinetic removal of lead and Kaolinite clay.
                                           77

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C2

Research:           In Situ Electrokinetics17

Developer(s):        West Virginia University

Contact(s):          Dr. Brian Reed
                     West Virginia University
                     Department of Civil and Environmental Engineering
                     647 Engineering Science Building
                     Morgantown, WV 26506
                     Telephone: (304) 293-3031 Ext. 613
                     E-mail: reed@cemr.wvu.edu


Research Description

Research on the use of electrokinetics to remediate fine-grained soil contaminated with lead was
conducted. The research included an evaluation of the impact of initial conditions on the
efficiency of electrokinetics to drive liquids and contaminants through soil samples.  An
electrokinetic soil reactor designed to mimic in situ electrokinetic flushing was applied to silt loam
artificially contaminated with lead.  Studies of the removal of lead from soils indicate that the
efficiency of lead removal is related to the flow of the acid front generated by the positive
electrode.

Status

The DOE National Research Center for Coal and Energy sponsored the laboratory studies
between September 30, 1987,  and June 30, 1993. Recent research on electrokinetics processing
has not been undertaken by the university  for the past few years.
          Information provided was obtained from the following report:

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,  In Situ Remediation
       Technology: Electrokinetics, EPA542-K-94-007, April 1995
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