Office of
Research and Development
Cincinnati, OH 45268
EPA 540/R-94/520a
November 1994
SITE Technology Capsule
Geosafe Corporation
In Situ Vitrification Technology
Abstract
The Geosafe In Situ Vitrification (ISV) Technology Is
designed to treat soils, sludges, sediments, and mine
tailings contaminated with organic, inorganic, and ra-
dioactive compounds. The organic compounds are py-
rolyzed and reduced to simple gases which are collected
under a treatment hood and processed prior to their
emission to the atmosphere. Inorganic and radioactive
contaminants are incorporated into the molten soil which
solidifies to a vitrified mass similar to volcanic obsidian.
This mobile technology was evaluated under the
SITE Program on approximately 330 yd3 of contaminated
soil at the Parsons site. Demonstration results indicate
that the cleanup levels specified by EPA Region V were
met and that the vitrified soil did net exhibit teachability
characteristics in excess of regulatory guidelines Process
emissions were also within regulator1)/ limits.
The Geosafe ISV Technology was evaluated based
on seven criteria used for decision-making in the Super-
fund Feasibility Study (FS) process. Results of the evalua-
tion are summarized in Table 1.
Introduction
This Capsule provides information on the Geosafe
ISV Technology, a process designed to treat contami-
nated media by using an electrical current to heat and
vitrify the subject material. The Geosafe ISV Technology
was investigated under the Environmental Protection
Agency (EPA) Superfund Innovative Technology Evalua-
tion (SITE) Program during March and April 1994 at the
former site of Parsons Chemical Works, Inc. (Parsons). The
Parsons site is a Superfund site located in Grand Ledge,
Ml and currently undergoing a removal action under the
supervision of the EPA Region V. Soils at the Parsons site
were previously contaminated by normal facility opera-
tions including the mixing, manufacturing, and packag-
ing of agricultural chemicals. The technology was evalu-
ated on these soils which were contaminated with
pesticides (primarily chlordane, dieldrin, and 4,4'-
DDT),metals (especially mercury), and low levels of dlox-
ins/furans. A total of approximately 3,000 yd3 of
contaminated soil was treated In nine pre-staged treat-
ment settings. The Demonstration Test evaluated the
system performance on one of these settings.
Information in this Capsule emphasizes specific site
characteristics and results of the SITE Demonstration at
the Parsons site. This Capsule presents the following infor-
mation:
• Technology Description
• Technology Applicability
• Technology Limitations
• Site Requirements
• Process Residuals
• Performance Data
• Economic Analysis
• Technology Status
• SITE Program Description
• Sources of Further Information
Technology Description
The ISV Technology demonstrated by Geosafe Cor-
poration (Richland, WA) operates by means of four
graphite electrodes, arranged in a square and inserted
a short distance into the soil to be treated. A schematic
of the Geosafe process is presented in Figure 1.
ISV uses electrical current to heat (melt) and vitrify
the treatment material In place. A pattern of electrically
conductive graphite containing glass frit is placed on
the soil in paths between the electrodes. When power is
fed to the electrodes, the graphite and glass frit con-
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Printed on Recycled Paper
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Table 1. Criteria Evaluation for the Geosafe In Situ Vitrification Technology
Criteria
Overall Protection of
Human Health and the
Environment
Compliance with ARARs Long-Term Effectiveness
Short-Term Effectiveness
Provides both short- and
long-term protection by
destroying organic con-
taminants and immobil-
izing inorganic material.
Remediation can be
performed in situ, there-
by reducing the need
for excavation.
Requires off-gas treat-
ment system to control
airborne emissions. Sys-
tem can be specifically
designed to handle emis-
sions generated by the
contaminants in the
media being treated.
Technology can simul-
taneously treat a mixture
of waste types (e.g., organ-
ic and inorganic wastes).
Requires compliance with
RCRA treatment, storage,
and land disposal
regulations (for a hazardous
waste). Successfully treated
solid waste may be de-
listed or handled as non-
hazardous waste.
Operation ofon-site treat
ment unit may require
compliance with
location-specific ARARs.
Emission controls may be
needed to ensure com-
pliance with air quality
standards denend!nn unor.
local ARARs and test
soil components.
Scrubber water will
likely require secondary
treatment before discharge
to POTWor surface bodies.
Disposal requires compli-
ance with Clean Water
Act regulations.
Effectively destroys
organic contamination
and immobilizes in-
organic material.
Reduces the likelihood
of contaminants leaching
from treated soil. ISV
glass is thought to have
a stability similar to
volcanic obsidian. The vit-
rified product is conserv-
atively estimated to re-
main physically and chem-
ically stable for approx-
imately 1,000,000 years.
May allow re-use of prop-
erty after remediation.
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Implementability
Cost
Effectively destroys
organic contamination and
immobilizes inorganic material.
Vitrification of a single
15-ft d'jep treatment
setting may be accom-
plished in approximately
ten days. Treatment times
will vary with actual treat-
ment depth and site-
specific conditions.
Presents potential short-term
exposure risks to workers
operating process equipment.
Temperature and electric
Some short-term risks
associated with air emissions
are dependent upon test
material composition and
off-gas treatment system
design.
Staging, if required, involves
excavation and construction
of treatment areas. A potential
for fugitive emissions and ex-
posure exists during excavat-
ion and construction.
Significantly reduces toxicity
and mobility of soil con-
taminants through treatment.
Volume reductions of 20 to
50% are typical after
treatment.
Some inorganic con-
taminants, especially
volatile metals, may escape
the vitrification process and
require subsequent treat-
ment by the off-gass treatment
system.
Some treatment residues
(e.g., litters, personal
protective equipment) may
themselves be treated
during subsequent
vitrification settings.
Residues from the final
setting, including
expended or contaminated
processing equipment may
require special disposal
requirements.
Volume of scrubber water
generated is highly
dependent upon soil
moisture content, ambient
air humidity, and soil
paniculate levels in the
off-gas.
A suitable source of
electric power is required
to utilize this technology.
Equipment is transportable
and can be brought to a
site using conventional
shipping methods. Weight
restrictions on
tractors/trailers may vary
from state to state.
Necessary support
equipment includes earth-
moving equipment for
staging treatment areas (if
required) and covering
tr&atod Si'oaS With Clean
soil. A crane is required
for off-gas hood placement
and movement.
The staging of treatment
areas is recommended for
areas where the
contamination is limited to
shallow depths (less than
eight feet).
The soil oxide composition
must provide sufficient
electrical conductivity in
the molten state and
adequate quantites of
glass formers to produce a
vitrified product. Oxides
can be added to soil to
corrected for deficiencies.
Groundwater should be
diverted away from
treatment area to improve
economic viability.
The estimated cost for
treatment when the soil is
staged into nine 15-ft
deep cells is approximately
$7BQfy& ($430/Ion). This
cost is based on data
gathered from the Parsons
site. Costs are highly site-
specific and will vary with
on-site conditions.
Treatment is most
economical when treating
large sites to maximum
depths.
Electric power is a major
element of costs associated
with ISV processing.
Other important factors (in
order of significance)
include labor costs; startup
and fixed costs; equipment
costs; and facility
modifications and
maintenance costs.
Moisture content of the
media being treated
directly influences the cost
of treatment since electric
energy must be used to
vaporize water before soil
melting occurs.
Sites that require staging
and extensive site
preparation will have
higher overall costs.
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Off-gas hood
Backup
off-gas
treatment
system
Glycol
cooling
Utility or
diesel
generated
power
Figure 1. Geosafe in situ vitrification proc&ss.
Scrubber water flow
Off-gas treatment system
To atmosphere
(if necessary)
ducts the current through the soil, heating the surround-
ing area arid melting directly adjacent soil.
Molten soils are electrically conductive and can con-
tinue to carry the current which heats and melts soil
downward and outward. The electrodes are allowed to
progress down into the soil as it becomes molten, con-
tinuing the melting process to the desired treatment depth.
One setting of four electrodes is referred to as a "melt,"
Performance of each melt occurs at an average rate of
approximately three to four tons/hr
When all of the soil within a treatment setting be-
comes molten, the power to the electrodes is discontin-
ued and the molten mass begins to cool. The electrodes
are cut near the surface and allowed to settle into the
molten soil to become part of the melt, Inorganic con-
taminants in the soil are generally Incorporated into the
molten soil which solidifies into a monolithic vitrified mass
similar in characteristics to volcanic: obsidian. The vitrified
soil is dense and hard, and significantly reduces th€* possi-
bility of leaching from the mass ove>r the long term,
The organic contaminants in the soil undergoing treat-
ment are pyrolyzed (heated to decomposition tempera-
ture without oxygen) and are generally reduced to simple
gases. The gases move to the surface through the dry
zone immediately adjacent to the melt, and through the
melt itself. Gases at the surface are collected under a
stainless steel hood placed over the treatment area and
then treated in an off-gas treatment system. The off-gas
treatment system comprises a quencher, a scrubber, a
demister, high efficiency particulate air (HEPA) filters, and
activated carbon adsorption to process the offgas be-
fore releasing the cleaned gas through a stack. A ther-
mal oxidizer can be used following the off-gas treatment
system to polish the offgas before release to the atmo-
sphere. A thermal oxidizer was utilized during the SITE
Demonstration at the Parsons site.
Technology Applicability
The Geosafe ISV Technology is a stand-alone pro-
cess that can be used to treat a wide variety of media
including soils, sludges, sediments, and mine tailings. It is
a mobile system with process equipment permanently
mounted on three trailers. The hood and remaining equip-
ment are transported on two additional trailers.
The soil type treated during the Demonstration was a
clay-like soil with some sand and gravel present. Con-
taminants suitable for remediation by this technology
may be organic or Inorganic. The technology has also
been successfully demonstrated on radioactive and
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mixed (hazardous and radioactive) wastes by Battelle
Memorial Institute for the U.S. Department of Energy, but
supporting data for this claim was not gathered as part
of the Demonstration Test. Testing to date does not indi-
cate an upper limit of contamination restricting success-
ful remediation if the composition of the material is suitable
for treatment (see Technology Limitations). The technol-
ogy is also being developed for buried waste, under-
ground tank, and barrier wall applications.
The technology can remediate contaminated mate-
rials in situ. Alternatively, contaminated materials may be
excavated, consolidated, and staged in prepared treat-
ment settings when the contamination zones are shallow
(less than eight ft) or scattered. Other processing con-
figurations are under development for unique applica-
tions.
Technology Limitations
The technology has the capability of treating large
areas in multiple treatment settings. -The size of each
treatment setting is dependent on the electrode spacing
appropriate for remediation. At the Parsons site, each
treatment setting covered a 27-ft by 27-ft ground surface
area. Adjacent settings can be melted until the entire
contaminated area is treated. Melt settings are config-
ured such that each area melts and fuses into the previ-
ous setting, leaving one large vitrified block after
treatment. This overlap ensures treatment of the material
between settings.
The maximum acceptable treatment depth with th€?
current equipment is 20 ft below land surface (BLS); how-
ever, full-scale tests at Geosafe's testing facilities in
Richland, WA have demonstrated that the technology
can successfully reach a depth of approximately 22 ft
BLS. Treatment at the Parsons site typically reached depths
of 15 to 19 ft BLS.
The presence of large amounts of water in the treat-
ment media may hinder the rate of successful applica-
tion of the Geosafe technology since electrical energy is
initially used to vaporize this water instead of melting^ the
contaminated soil. The resulting water vapors must also
be handled by the off-gas treatment system. Treatment
times are thus prolonged and costs increased when ex
cess water is present.
The overall oxide composition of th«j test soil deter-
mines properties such as fusion and melting tempera-
tures, and melt viscosity. Soil to be treated must contain
sufficient quantities of conductive cations (K, LJ, and Na)
to carry the current within the molten mass. Additionally.
the soil should contain acceptable amounts of glass form-
ers (Al and Si). Most soils worldwide have an acceptable
composition for ISV treatment without composition modi-
fication. Geosafe determines the oxides present In tine
soil prior to treatment. A computer-based model is then
used to determine the applicability of the site for vitrifica
tlon. The model can also identity oxide composition levels
that require modification before treatment.
The type of contamination present on-site affects the
off-gas treatment system more dramatically than it af-
fects the rest of the ISV system. For this reason, the off-gas
treatment system is modular In configuration, allowing
treatment of the off-gases to be site-specific. The extent
of modularity is expected to increase with future units.
Heat removal limitations of the current equipment
dictate that the organic content of the treatment media
be less than 7 to 10% by weight. To minimize pooling of
treated metals at the bottom of a melt, which may result
in electrical short-circuiting, metals content must be less
than 15% by weight. The volume of inorganic debris is
limited to 20% or less.
Previous experience has indicated that safe, effec-
tive treatment cannot be assured when pockets of vapor
or buried drums exist beneath the soil surface. The gases
released may cause bubbling and splattering of molten
material, resulting In a potential safety hazard. For this
reason, extensive site characterization is recommended
prior to treatment if buried drums are suspected. Com-
bustible materials generally do not present processing
difficulties since they decompose relatively slowly as the
melt front approaches. Full-scale demonstrations have
been successfully conducted on sites containing signifi-
cant quantities of combustibles such as wooden timbers,
automobile tires, personal protective equipment, and plas-
tic sheeting.
Site Requirements
The site requirements for the Geosafe ISV technology
are a function of the size of the equipment used. The site
requirements are also determined, in part, by whether
the soil is excavated and staged prior to treatment. Ad-
equate area is required to accommodate staging, if
employed, and to support the off-gas treatment system
and the power conditioning system which feeds the elec-
trodes. Space for maneuvering a crane is also necessary
to allow placement and removal of the off-gas contain-
ment hood and to assist in the placement of the elec-
trodes.
At the Parsons site, the original soil contamination
was relatively shallow, five ft or less, and located in three
main areas. To increase the economic viability of treat-
ment at this site, the contaminated soil was excavated
and consolidated Into a series of nine treatment cells.
The cell walls were built using concrete, cobble, and
particle board as shown in Figures 2 and 3. The cells were
constructed by trenching an area of the site, installing
particle board and concrete forms, and pouring con-
crete into the forms to create the nine cell settings. A
one-ft layer of cobble was placed in the bottom of each
cell, and approximately two ft of cobble was used to
surround the exterior of the cell forms. The use of cobble
at the sides was intended as a means to retard melting
out into adjacent clean soil. The bottom cobble was
used to provide a drainage pathway for water that was
known to be present on-site; the resultant flow of water
was directed to a drainage trench. After construction,
the cells were filled with contaminated soil from the site,
and topped with a layer of clean soil.
During the treatment of the first few cells, problems
with the cell design were observed. The intense heat that
was melting the soil was also thermally decomposing the
particle board forms. Analysis of water samples collected
from the diversion system surrounding the cells identified
volatiles (benzene), phenolics, and epoxies that were
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Electrode
Clean fill (soil)
Concrete wall
Figure 2. Side view of typical treatment cell.
1 ' Concrete wall
2' Cobble fill
//?/f/a//y p/anngd bcatjon Qf
12' dia. electrode (typical)
o o o o
L
V
O O
0 O
V
O O
00
/\
{/
f °
Cell 8
demonstration
i,V\
C/ean fill surrounds cobble.
Figure 3. Plan view of treatment cells.
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released by this decomposition. The cobble outside of
the cells created porous paths in the vicinity of treatment,
thereby increasing the likelihood of vapors escaping the
area outside the hood and causing irregular melt shapes.
Geosafe responded by excavating the area outside
of the remaining treatment cells and removing the par-
ticle board forms. A refractory ceramic material with Insu-
lating and reflective properties was placed adjacent to
the exterior of the concrete cell walls. This helped to
control the melt shape, limit fugitive vapor emissions, and
restrict the melt energy inside the cell boundaries. Based
upon the experience Geosafe gained at the Parsons site,
the design and construction of staged treatment cells will
be modified for future projects. It should be noted that
the use of cobble in treatment cell construction was
unique to the Parsons site where the configuration and
flow of the on-site groundwater dictated Its application.
Utility requirements for this technology include elec-
tricity, natural gas (if a thermal oxidizer is used), and
water. As expected, electricity is a major consideration
when implementing ISV. Total power to the electrodes
during treatment is approximately three MW; the voltage
applied to each of the two phases during steady state
processing averages around 600 volts while the current
for each phase averages approximately 2,500 amps. Dur-
ing treatment of the Demonstration Test cell (Cell 8)
energy to the electrodes totalled 613 MWh. Energy de-
mands for other cells at the Parsons site differed—prima-
rily because of variations in the soil moisture content.
Process Residuals
The primary residual generated by the Geosafe ISV
technology is the vitrified soil product. This material is
generally left intact and in place at the conclusion of
treatment. The treated volume may take one to two
years to cool completely.
A number of secondary process waste streams are
generated by the Geosafe technology. These Include air
emissions, scrubber liquor, decontamination liquid, car-
bon filters, scrub solution bag filters, HEPA filters, used
hood panels, and personal protective equipment (PPE),
Gaseous emissions which meet regulatory requirements
are discharged directly to the atmosphere following treat-
ment. The amount of scrubber liquor and filter waste
generated depends on the nature of the treatment me-
dia. Factors such as high off-gas paniculate loading and
high soil moisture content may result In large quantities of
these materials. The number of used hood panels requir-
ing disposal depends on the type and extent of contami-
nation at the site, the corrosiveness of the off-gases
generated during treatment (as well as the corrosion-
resistance of the hood panels), and the duration of treat-
ment.
Some process residuals (e.g., used scrub solution bag
filters, HEPA filters, and PPE) can be disposed in subse-
quent melt settings to reduce the volume of these materi-
als requiring ultimate disposal off-site. Scrubber water
generated during treatment may require special han-
dling depending upon the type and level of contami-
nants being treated.
Performance Data
The Geosafe ISV technology was evaluated to deter-
mine its effectiveness in treating soil contaminated with
pesticides and metals. Cell 8 was selected for the Dem-
onstration Test since it exhibited the highest levels of con-
tamination whereby demonstration objectives could be
evaluated. The critical objective for this project was to
determine if final soil cleanup levels set by the EPA Region
V could be achieved. These specified cleanup levels
included 1,000 jig/kg for chlordane, 4,000 jig/kg for 4,4'-
DDT, 80 ^g/kg for dleldrln, and 12,000 ^ig/kg for mercury.
Non-critical objectives for this project were:
• to evaluate the leachability characteristics of chlor-
dane, 4,4-DDT, dieldrin, and mercury in the pre-
treatment soil using the toxicity characteristic
leachability procedure (TCLP) and determine whether
the leachability characteristics of these compounds
in the vitrified residue meet the regulatory limits speci-
fied in 40 CFR §261.24. (Note: only chlordane and
mercury are listed.);
• to determine the approximate levelsof dioxins/furans,
pesticides (specifically chlordane, 4,4'-DDT, and di-
eldrin), mercury, and moisture in the pre-treatment
soil;
• to characterize the liquid residues (scrubber water) of
the process with respect to pesticide and mercury
concentrations;
• to evaluate emissions from the process;
• to identify the operational parameters of the technol-
ogy;
• to develop operating costs and assess the reliability
of the equipment; and
• to examine potential impediments to the use of the
technology including technical, institutional, opera-
tional, and safety impediments.
Approximately 3,000 yd3 (5,400 tons) of contaminated
soil was excavated and staged into nine treatment cells.
Prior to treatment, three primary soil cores were obtained
from Cell 8 to characterize the concentrations of pesti-
cides, dioxins/furans, and metals. Samples were also col-
lected to determine the leachability characteristics of
pesticides and mercury before treatment. In addition,
samples were taken for the analysis of grain size, moisture,
density, and permeability. Prior to treatment, potable wa-
ter was charged to the scrubber system, and then sampled
and analyzed for volatile and semivolatile organic com-
pounds, pesticides, dioxins/furans, and metals. The scrub-
ber water was again sampled and analyzed for these
parameters during treatment.
Samples of the stack gas were collected during treat-
ment. The samples were analyzed for volatiles,
semivolatiles, pesticides, dioxins/furans, metals, hydrogen
chloride, and particulates. The stack gas was also moni-
tored for oxygen, carbon monoxide, and total hydrocar-
bons using continuous emission monitors.
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System parameters including, but not limited to, volt-
age and amperage applied to the molten soil, hood
vacuum, and off-gas treatment train operational cittribut€ss,
were monitored during treatment. Measurements were
taken every minute and recorded by computer. Addi-
tional parameters such as hood skin and plenum tem-
peratures, scrubber pH and volume, and differential
pressures across the scrubber system and filters wei e manu-
ally recorded regularly.
Three primary post-treatment vitrified soil samples were
collected from the surface of Cell 8. Analysis of the sur-
face samples was Intended to provide immediate Infor-
mation regarding the condition of the soil until samples
more representative of the center of the treatment area
can be safely obtained. Additional sampling is scheduled
to be performed after the molten mass has sufficiently
cooled (in approximately one yr). The surface samples
collected immediately after treatment were analyzed for
pesticides, dloxlns/furans, and metals. The TCLP was also
performed on these samples to determine the teachabil-
ity of the treated soil. Post-treatment samples were col-
lected from the scrubber water and analyzed for volatile^,
semivolatiles, pesticides, dioxins/furans, and metals.
Table 2 summarizes the range of selected analytical
results from samples collected during the Demonstration.
Because of the limited number of samples collected,
ranges are presented rather than average values. The
data presented in this table are limited to analytes that
were of concern during th€» Demonstration and important
in evaluating test objectives. Concentrations below the
respective reporting detection limits are indicated by a
'less than" symbol (i.e., <).
Evaluation of the data suggests the following results
and conclusions:
• The technology successfully treated the soil, com-
pleting the test cell melt in ten days with only minor
operational problems. During this time, approximately
330 yd3 (approximately 600 tons) of contaminated
soil was vitrified, according to Geosafe melt summa-
ries. Approximately 613 MWh of energy was applied
to the total soil volume (estimated to be 475 yd3)
during vitrification of Cell 8; energy applied to the
actual contaminated soil volume could not be inde-
pendently measured because clean fill and surround-
ing uncontaminated soil are vitrified as part of each
melt. System operation was occasionally interrupted
briefly for routine maintenance such as electrode
system addition and adjustment.
• The treated (vitrified) soil metthe EPA Region V cleanup
criteria for pesticides and mercury. Target pesticides
were reduced to levels below their analytical report-
ing detection limits (<80 fig/kg for chlordane, <16 jj,g/
kg for 4,4'-DDT and dieldrin) in the treated soil. Mer-
cury, analyzed by standard SW-846 Method 7471
procedures, was reduced to less than 40 jj.g/kg in the
treated soil. Although the concentration of pesticides
and mercury were below the cleanup criteria in some
samples, significant contaminant reductions were
achieved. Chlordane was not detected in any of the
Table 2. Selected Data Summary Results
Pesticides
Pre-Treatment Soil (fJ.g/kg)
Post-Treatment Soil fag/kg)
Pre-Treatment TCLP ftig/L)
Post-Treatment TCLP (ng/L)
Stack Emissions
Stack Emissions (Ib/hr)
Chlordane
<80
<80
4,4' DDT
2,400-23,100
Dieldrin
1,210 - 8,330
<0.5
<0.5
<1.38
0.120-0.171
<0.28
<2.2X10*
6.5 - 10.2
<0.28
<2.2 X 10-6
Metals
Pre-Treatment Soil fag/kg)
Post-Treatment So/7* (/ng/kg)
Stack Emissions
Stack Emissions (Ib/hr)
Arsenic
Chromium
8,380- 10,100
717-5,490
Pre-Treatment TCLP fag/L) NA
Post-Treatment TCLP (pg/L) <4 - 30.5
<0.269
<12.93 X i
Lead
Mercury
37,400 - 47,600
12,500 - 14,600
NA
<10- 17.1
2.081 -3.718
1.43X 10-5
2.67X1 a5
<50,000
<5,000 - 21,000
NA
<50 - 4,290
<3.891
<2.82 X m5
2,220-4,760
<40
<0.2
<0.2 - 0.23
12.9- 17.7
9.89 X 10-5-
1.25X10^
< Indicates that analyte was not deteced at or above the reporting detection limit (value presented).
* Values presented were obtained using standard SW-845 digestion and analytical methods. These soil methods are EPA-approved, however,
other non-approved methods may provide more accurate metal determinations for vitrified materials.
NA Indicates that the sample was not analyzed for this parameter.
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SITE Demonstration samples, but were detected in
samples collected by EPA Region V.
• The solid vitrified material collected was subjected to
TCLP for pesticides and mercury. No target pesticides
were detected in the leachate; the average leach-
able mercury was approximately 0.2 |ig/L, well below
the regulatory limit of 200 ng/L (40 CFR Part 261 24).
• Stack gas samples were collected during the Dem-
onstration Testto characterize process emissions. There
were no target pesticides detected in the stack gas
samples. During the Demonstration Test, mercury
emissions averaged 16 jig/m3 (1.1 xlO"4 Ib/hr). The
emissions were below the regulatory requirement of
88 ^ig/m3 (5.93 x 1Q-4 Ib/hr). Other metal emissions in
the stack gas (specifically arsenic, chromium, and
lead) were monitored and found to meet regulatory
standards during testing. Stack gas dispersion model-
ing by Region V indicated that metal emissions during
treatment were not a human health risk.
• Emissions of total hydrocarbons and carbon monox-
ide were regulated at 100 ppmV (as propane) and
150 ppmV, respectively. Throughout the Demonstra-
tion Test, vapor emissions of these gases (measured
downstream from the thermal oxidizer) were each
consistently below 10 ppmV—well below the regula-
tory guidelines.
• Scrubber water generated during the Demonstration
Test contained volatile organics, partially oxidized
semi volatile organics (phenolics), mercury, and other
metals. The scrubber water underwent secondary
treatment off-site before ultimate disposal and data
suggest that seconda ry treatment o f this waste strea m
is likely in most cases.
• Pre-treatmentsoil dry density averaged 1.48 tons/yd3,
while post-treatment soil dry density averaged 2.10
tons/yd3. On a dry basis, a volume reduction of ap-
proximately 30 % was observed for the test soil.
Key findings from the demonstration, including com-
plete analytical results and the* economic analysis, will be
published in an Innovative Technology Evaluation Report.
This report will be used to evaluate the Geosafe ISV Tech-
nology as an alternative for cleaning up similar sites across
the country. Information will also be presented in a SITE
Demonstration Bulletin and a videotape.
Economic Analysis
Estimates on capital and operating costs have been
determined for a treatment volume of approximately 3,200
yd3 (5,700 tons). This is slightly higher than the total treat-
ment volume at the Parsons site, but it is based on the
treatment configuration used at this site* (nine treatment
cells measuring 27 ft by 27 ft by 15 ft (deep with 2 ft of
clean fill on top of the contaminated soil). This information
was extrapolated to determine a treatment cost for
remediating approximately 970 yd3 (nine treatment cells
measuring 27 ft by 27 ft by 5 ft deep with 1 ft of clean fill)
and approximately 4,400 yd3 (nine treatment ceils mea-
suring 27 ft by 27 ft by 20 ft deep with 2 ft of clean fill). The
cost for the treatment of approximately 3,200 yd3 (5,700
tons) of soil is based on the SITE demonstration at the
Parsons site and is estimated to be approximately $780/
yd3 ($430/ton). For lesser volumes of soil (970 yd3, as de-
scribed above), the cost becomes approximately $1,500/
yd3 ($850/ton). For larger volumes of soil (4,400 yd3, as
described above), the cost becomes approximately $670/
yd3 ($370/ton). The primary determinants of cost are the
local price of electricity, the depth of processing, and the
soil moisture content. Treatment volume (and therefore
treatment time) is the key variable between the costs of
these three cases. The cost of time-dependent factors
including equipment rental, labor, consumables and sup-
plies, and utilities varies directly with treatment time.
The primary cost categories include utilities, labor,
and startup and fixed costs, each contributing roughly
20% to the total cost (utilities slightly higher). The contribu-
tion of utilities increases markedly with increased treat-
ment volume. Equipment costs and facilities modifications
and maintenance costs are each responsible for roughly
10% of the total treatment cost. Treatment is most eco-
nomical when treating large sites to maximum depths,
particularly since time between melts is minimal com-
pared to actual treatment time.
The cost for treatment using the Geosafe ISV technol-
ogy is based on, but not limited to, the following assump-
tions:
• The contaminated soil is staged into treatment cells
by an independent contractor prior to Geosafe's
arrival on-site. Cell preparation and construction are
site-specific and may be different for each case,
however, it is assumed that each site is prepared in a
manner similar to the Parsons site.
• The depth of treatment is assumed to exceed the
depth of contamination by at least one ft to ensure
that the melt incorporates the floor of the cell and
beyond.
• Treatmenttakes place 24 hr/day, 7 days/wk, 52 wk/yr.
An on-line efficiency factor of 80% has been incorpo-
rated to account for down-time due to scheduled
and unscheduled maintenance and other unfore-
seen delays.
• Operations for a typical shift require one shift engi-
neer and one operator. In addition, one site manager
and one project control specialist are present on-site
during the day shift. Three shifts of workers are as-
sumed to work eight hr/day, seven day/wk for three
weeks. At the end of three weeks, one shift of workers
is rotated out, and a new set replaces the former.
• The costs presented (in dollars/cubic yard) are calcu-
lated based on the number of cubic yards of con-
taminated soil treated. Because clean fill and
surrounding uncontaminated soil are treated as part
of each melt, the total number of cubic yards of soil
treated is higher than the number of cubic yards of
contaminated soil treated. Costs/cubic yard based
on total soil treated would, therefore, be lower than
the costs presented in this estimate.
If Geosafe scales its process differently than assumed
In this analysis (a likely scenario), then the cost of
remediation/cubic yard of contaminated soil will change.
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These cost estimates are representative of charges
typically assessed to the client by the vendor and do not
include profit. The costs presented In this economic analysis
are based upon data gathered at the Parsons site. The
developer claims these costs were unusually high, and
expects the treatment costs for future sites to be ess than
the treatment costs for the Parsons site. A detailed expla-
nation of these costs is included in the Innovative Tech-
nology Evaluation Report.
Technology Status
The technology was originally developed by Pacific
Northwest Laboratory, operated by Battelle Memorial In-
stitute, and has been undergoing testing and develop-
ment since 1980. A majority of the development work was
performed the U.S. Department of Energy, however, sig-
nificant work also has been done for various private and
other government sponsors. The technology has been
licensed exclusively to Geosafe Corporation for the? pur-
pose of commercial applications of hazardous ai id radio-
active waste remediation. To date, the technology has
been tested on a wide variety of hazardous chemical,
radioactive, and mixed wastes. Treatability tests are typi-
cally conducted on an engineering scale (TOO to 200 Ib
melts) to determine potential applicability of the technol-
ogy. Geosafe has also conducted full-scale In siti i opera-
tional acceptance tests at their facility In Richiand, WA.
The work performed at the Parsons site was the first com-
mercial full-scale application of the ISV technology.
The Records of Decision for five U.S. Department of
Defense and EPA-lead Superfund sites (including the Par-
sons site) have identified ISV technology as the preferred
remedy for cleanup. ISV also has been identified as an
alternative cleanup option at two additional sites. Cur-
rently, Geosafe is scheduled to perform full-scale
remediation activities for other customers at sites con-
taminated with PCBs, chlorinated organics, and toxic met-
als. Treatment at each of these sites involves some amount
of debris or otherwise foreign materials. In situ or staged in
situ configurations will be used for the planned
remediations.
Higher levels of contamination at other sites are not
expected to represent a significant challenge to the pro-
cess. For these sites, it may be possible to obtain destruc-
tion and removal efficiencies (DRE) if contaminants are
present at high enough levels. DRE calculations were not
possible at the Parsons site due to the low levels of target
organics.
Operational parameters that affect the overall pro-
cess performance have a much larger influence on suc-
cessful application of ISV than contamination levels.
Factors such as high soil moisture, extreme depths (deep
or shallow), the presence of sealed drums, and : oil corn-
position are the primary factors that influence lemedial
design and operation. With proper management, it is
anticipated that the process may successfully be applied
at other sites with higher levels of contamination
SITE Program Description
(CERCLA), also known as Superfund. CERCLA was
amended by the Superfund Amendments and Reautho-
rization Act (SARA) In 1986. The SITE Program is a formal
program established in response to SARA. The primary
purpose of the SITE Program is to maximize the use of
alternatives in cleaning up hazardous waste sites by en-
couraging the development and demonstration of new,
innovative treatment and monitoring technologies. It con-
sists of four major elements: the Demonstration Program,
the Emerging Technology Program, the Monitoring and
Measurement Technologies Program, and the Technol-
ogy Transfer Program. The Geosafe ISV Technology was
demonstrated under the Demonstration Program. This
Capsule was published as part of the Technology Trans-
fer Program.
Disclaimer
While the technology conclusions presented in this
report may not change, the data has not been reviewed
by the Quality Assurance/Quality Control office.
Sources of Further Information
EPA Contacts:
U.S. EPA Project Manager:
Teri Richardson
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
Telephone No.: 513/569-7949
Fax No.: 513/569-7620
Technology Developer:
James E. Hansen
Geosafe Corporation
2950 George Washington Way
Richiand, WA 99352
Telephone No.: 509/375-0710
Fax No.: 509/375-7721
References
Hansen, James E. 1993. "In Situ Vitrification (ISV) for
Remediation of Contaminated Soil Sites." Geosafe Cor-
poration. Richiand, WA.
SAIC. 1993. "Geosafe In Situ Vitrification Demonstra-
tion Plan; Superfund Innovative Technology Evaluation."
Science Applications International Corporation. San Di-
ego, CA.
USEPA. 1992. Handbook on Vitrification Technologies
for Treatment of Hazardous and Radioactive Waste. EPA/
625/R-92/002. U.S. Environmental Protection Agency. Of-
fice of Research and Development. Washington, D.C.
In 1980, the U.S. Congress passed the Comprehensive
Environmental Response, Compensation, and Liability Act
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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EPA
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