NCD980602163_19991014_Warren County PCB Landfill_SERB C_Response for RFI Landfill Detoxification Projects Treatment and Restoration Demobilizatiion-OCR

f
October 14, 1999
Response for RFI
Landfill Detoxification Projects
Treatment and Restoration/Demobilization
Prepared for
North Carolina Department of
Environment and Natural Resources
Division of Waste Management
Attn: Pat Backus
1646 Mail Service Center
Raleigh, MC 27699-1646
Midwest Soil Remediation, Inc.
1480 Sheldon Drive
Elgin, IL 60120
847-742-4331
This response includes data and equipment descriptions that
shall not be disclosed outside NC-DENR and shall not be
duplicated, used, or disclosed--in whole or in part--for any
purpose other than to evaluate this proposal. If, however, a
contract is awarded to this offeror or quoter as a result of--or
in connection with--the submission of these data, NC-DENR
shall have the right to duplicate, use, or disclose the data to
the extent provided in the resulting contract. This restriction
does not limit NC-DENR's right to use Information contained in
these data if they are obtained from another source without
restriction.
Midwest Soil Remediation, Inc.
1480 Sheldon Drive
Elgin, IL 60120
847-742-4331
Executive Summary
This response is for North Carolina Department of Environment and Natural Resources use
in planning the treatment of PCB contaminated soils at the Warren County landfill.
Midwest Soil Remediation, Inc. owns and operates a high capacity indirect heated thermal
desorption unit that can perform this project. This unit operates at about 25 ton/hr on PCB
soils and the corresponding operating cost is roughly 1/2 that of similar lower capacity units
available in the soil remediation market. The BCD detoxification chemistry can be readily
implemented with this unit, if that is NC-DEN R's desire.
Midwest Soil works closely with TD*X Associates on this type of project under specific
technical service agreements and technology licenses. TD*X staff developed and operated
what was previously the largest available transportable indirect heated thermal desorber.
TD*X has safely treated 110,000 tons of PCB soil with this unit, and will bring that
experience to the Warren County project with MSR. TD*X has also successfully performed
full-scale PCB chemical detoxification using alkaline dechlorination, the predecessor
technology to BCD .
Contact personnel for Midwest Soil are either Bruce Penn, at 847-742-4331, or Carl Palmer
with TD*X, at 919-468-1266. TD*X is located in Research Triangle Park, NC, and will be
able to provide excellent support of both NC-DENR and the Warren County site during the
project planning, permitting, and execution.
Bruce Penn
General Manager
Midwest Soil Remediation
Carl R. Palmer
Director, Thermal Process Group
TD*X Associates
TABLE OF CONTENTS
1.0 RFI RESPONSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 TECHNICAL APPROACH ......................................... 2
2.1 Detoxification Unit Design 3
2.2 TDU Ability to Meet Performance Requ irements 5
List of Figures
High Capacity Indirect TDU Process Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
List of Tables
Table 1. RFI SPECIFIC INFORMATION REQUESTED
Midwest Soil and TD*X Associates
Indirect Heated Thermal Desorption Projects . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Test Results -Dioxins/Furans, PCBs and Their Precursors ............. 7
APPENDIX A
APPENDIX B
Appendices
Technical Bulletins
Photographs
II
1.0 RFI RESPONSE
This response is to provide specific information requested by NC-DENR for the
detoxification of the Warren County landfill site soils. Midwest Soil Remediation, Inc.
(MSR) owns and operates an indirect heated thermal desorption unit that is particularly well
suited to this project. This unit has the highest capacity of any similar unit in the US.
Furthermore, our staff, which includes TD*X Associates personnel, have performed
multiple large scale PCB remediation projects using both indirect heated thermal
desorption and chemical detoxification of PCBs.
Table 1. RFI SPECIFIC INFORMATION REQUESTED
Midwest Soil and TD*X Associates
Indirect Heated Thermal Desorption Projects
PROJECT NAME WASTE QUANTITY DURATION TREATMENT
LEVEL ACHIEVED
Lucent Technologies, 33 ,000 tons 3 months < 0.01 o ppm voes
Montgomery, IL chlorinated
hydrocarbons
Re-Solve Superfund 50,000 tons 13 months < 2 ppm PCB
Site, North Dartmouth PCB soil and sludge
MA
Sangamo Superfund 60,000 tons 14 months < 2 ppm PCB
Site, Pickens, SC PCB soil and sludge
Hilton Davis Site 60,000 tons 14 months complex organics
Cleanup, Cincinnati, chloroaniline dye to less than 1 ppm
OH sludQe
These four projects have given MSR and TD*X unmatched experience that is valuable to
the Warren County project; the first two in particular. Appendix A has technical bulletins
describing both of these projects.
On the Lucent Technologies project, we used our new high capacity indirect (HCI) heated
thermal desorption unit (TDU). This unit was operated consistently at 45 to 50 ton/hr
throughout the project. When the higher treatment temperature that is required for PCB
separation is considered, the HCI-TDU would operate at about 25 ton/hr on the Warren
County project. This is about double that of the next highest capacity TDU in the market.
This high capacity will directly benefit the project in reduced operating cost, as well as a
shorter schedule and associated site overhead costs .
1
On the Re-Solve project, TD*X personnel invented, designed, built and operated the
indirect heated TDU, and also performed on-site chemical detoxification of the PCBs.
During extensive testing performed by USEPA, the thermal desorber established
benchmark performance results for both PCB removal and air emissions control. The key
performance measure for a TSCA permitted treatment unit is the PCB "destruction and
removal efficiency." At Re-Solve, the "DRE" was measured at greater than 99 .9999996%
while feeding soil with up to about 500 ppm PCBs. We also performed chemical
detoxification of the condensed PCB oil. This oil had about 10% PCB levels, and was
detoxified on-site using alkaline dechlorination in a stirred tank reactor. This technology
was a precursor to BCD, and it differs only in the reactants that are used. TD*X experience
with full-scale PCB dechlorination will be directly beneficial to the Warren County project.
Ability to Mobilize Equipment. MSR's high capacity indirect TDU is currently available
to perform the project. We would mobilize the unit after receipt of operating approval from
the regulatory authority, which we assume to be USEPA Region IV, Toxic Substances
branch. TD*X has worked with these personnel on TSCA permitted PCB thermal
desorption and chemical dechlorination work performed at Clemson. We would expect it
to take four to six months to receive approval to mobilize after the EPA receives a complete
permit application document. This is not an unreasonable time length, since even
Superfund site work must go through work plan preparation and approval that takes a
similar or greater time period. After permission is given to mobilize, we would require about
two to three weeks to ship and assemble the TDU on a properly prepared site . The TDU
ships on about ten to twelve trailers. The BCD reactor is a single trailer load. Shakedown
operations would then be performed and a demonstration test conducted within the first
several weeks of operation at the site.
Ability to Work With Community. MSR and TD*X routinely perform thermal desorption
projects in close proximity to community residents. We are very sensitive to the
requirements of these sites to maintain low impact operations, as well as to remain open
and accessible to visitors . The Lucent Technologies cleanup was performed in suburban
Chicago with resident's homes basically bu ilt right up to the site fence. The Re-Solve
project was performed in a location about 15 miles west of New Bedford, MA; also with
resident's home sites sharing the site fence line, and within plain view of the TDU . Both
projects were performed without adverse public impacts. In fact, during the same time
period that TD*X staff were routinely operating at Re-Solve, an incinerator project in New
Bedford was shut down and indefinitely put on hold at great expense to the EPA. We did
work through an issue at Re-Solve regarding the noise from the backup horn on the loader,
but that was our only notable public concern .
2.0 TECHNICAL APPROACH
We will be using our proven high capacity indirect TDU, specially equipped with a
condensation and recovery gas treatment system, and a BCD reactor to detoxify the
recovered PCB oil on-site. The components of this system have been used by MSR and
TD*X to treat a combined 200,000 tons of highly regulated hazardous waste contaminated
soils and sludges by some of the same key personnel who will perform this project. The
2
results for these projects set multiple performance benchmarks in the thermal treatment
industry that have yet to be surpassed .
We would purchase a project specific license for BCD from USEPA for the Warren County
landfill project. These licenses are available to any qualified vendor. MSR has already had
discussions with USEPA's Cincinnati technology transfer office regarding acquiring this
license, and we meet their requirements. Since this license does not convey any
equipment or other capability, no vendor, even one claiming to hold a current license,
would have an advantage over MSR to implement BCD. More important than having the
license, we have the most cost effective equipment available to implement BCD at the full-
scale.
We would also retain the chemists who developed BCD for EPA to support our project
team and supplement TD*X staff knowledge in this area. Specifically, we would work with
Dr. Thomas Tiernan of Wright State University. Dr. Tiernan did the process chemistry
development work on BCD, as well as its predecessor technologies (APEG and KPEG},
working closely with the USEPA's Dr. Charles Rogers. TD*X has collaborated in this same
fashion with Dr. Tiernan and his staff to offer BCD on the New Bedford Harbor hot spot
technology demonstration program. In this way, we will put the best combination of
fundamental knowledge and experienced field personnel together on the project.
2.1 Detoxification Unit Design
The basic process flow is presented in the figure below. Contaminated materials are fed
continuously into an indirectly heated thermal processor to desorb the PCB contaminants
Treated solids are discharged to a clean stockpile after cooling and wetting. Since neither
the contaminated solids nor the separated contaminants ever contact the burner's flue gas,
the products of combustion are clean and are discharged to the atmosphere without
emission control devices.
The contaminants are transferred with an inert carrier gas to the off-gas treatment system
for condensation and recovery. Full scale operations on PCBs have confirmed that the
contaminants are recovered and not degraded or destroyed as they would be in an
incinerator-type device. The recovered PCB oil will be detoxified in a BCD reactor. The
BCD reagents (sodium bicarbonate, carbon catalyst and sugar) are added to the PCB oil
in a stirred tank, which is then heated for several hours to allow the detoxification reaction
to take place. The detoxified oils are then shipped offsite for recycling, recovery or
disposal based on their characteristics.
An important result that was obtained in our full-scale operations at Re-Solve regards the
disposal of the detoxified oil. After chemical dechlorination, we produced an oil that was
not regulated under TSCA at Re-Solve. However, we could not find an oil recycler or
energy recovery facility that would take this oil based on its chlorine content. We were
therefore required to send this oil to an incinerator. A negative aspect of this was that the
detoxified oil volume was four to seven times greater than the original PCB oil volume
because of the volume of the reagents that were added to it for detoxification. This volume
3
CARRIER GAS RECYCLE
CLEAN :-{]-+ PROCESS
NITROGEN
-·
NON-CONTACT
FLUE GAS
t
HIGH CAPACITY
INDIRECT HEATED
THERMAL PROCESSOR
High Capacity Indirect TDU Process Flow
FILTERS VENT
;j
':OFF-GAS CONDENSING ~-.y
RECOVERY SYSTEM
RECOVERED ~-· OIL
CONDENSED
WATER
,___ __ ___.__ ____ _ CLEAN
SOLIDS :
I
·--~-I
increase went contrary to EPA's waste minimization policies. Furthermore, the incinerator
gave a disposal approval for the 10% PCB oil prior to detoxification. As a result, EPA
agreed that there was no benefit to on-site PCB oil dechlorination at Re-Solve, and agreed
that the PCB oil could be incinerated off-site [and accepted a $22/ton-soil price reduction
for eliminating the dechlorination requirement]. While the specific chemistry and material
balance may be different for the Warren County project, it would be advisable to keep
multiple oil disposal options open when the detailed design is performed. In any event, the
detoxified oil may require off-site incineration if no other disposal outlet can be identified.
In order to prevent unwanted emissions, the dryer is well sealed and the system pressure
is kept negative. A portion of the treated off-gas is purged, and the balance is returned to
the dryer as the carrier gas. This vent is at a very low purge gas flow rate, typically less
than 100 scfm , allowing highly efficient APC devices for it. The process vent gas can be
cleaned to any required emission standard. In most cases, small filters are used to remove
particulate matter and hazardous organic air pollutants to well below the national
standards. We plan to use a pre-filter, a HEPA filter and carbon adsorber for the Warren
County project to control particulate matter and PCB emissions from the process vent. Our
prior full-scale experience on 110,000 tons of soil has shown no-detectible PCB emissions
with this system .
The equipment that handles the contaminated soil is all designed to mIrnmIze
contamination of the process area, and uses covered or totally enclosed conveyors. The
dryer is well sealed to control both air in-leakage as well as fugitive emissions. It is also
4
operated at a negative draft. The treated soil handling equipment is covered through the
soil cooling and wetting operation, and maintained at a negative draft to control nuisance
dusts. The gas handling system is operated at negative pressure up through the
condensers and recirculation blower (where the majority of the contaminants have been
removed) to minimize emissions. The gas handling equipment is well sealed with flanges
and welded construction, and is leak checked during pre-operational functional testing to
confirm primary containment of the process gases. Similarly, the liquid handling equipment
are constructed to meet the substantive requirements of both the RCRA Subpart J (Tank
Systems) and TSCA standards for primary and secondary containment. Tanks and their
piping systems are designed and constructed to preform primary containment, and the
concentrated residues from the condensation system are managed in tanks and piping that
has secondary containment provided by integral steel containment built into the trailer
frames. In this regard, the processing pad will serve as a prudent contamination control
measure, but will not carry the burden of providing secondary containment.
2.2 TDU Ability to Meet Performance Requirements
The key performance requirements are that the TDU have the ability to remove the soil
contaminants to the treated soil standards and that the air emissions are within approved
limits as established by both the project specification and the permits. MSR and TD*X
have significant experience in both of these areas, and the High Capacity Indirect TDU will
meet these requirements routinely with superior results.
TD*X designed and operated indirect heated thermal desorption units have been used at
both the full-scale and pilot-scale on highly regulated polychlorinated biphenyls (PCBs).
For the Warren County project, the key factor in meeting soil treatment standards is the
ability to routinely operate the indirect dryer's soil discharge temperature at 800-950°F.
The MSR unit has an alloy cylinder, and can achieve these temperatures while operating
at a nominal 25 ton/hr capacity on the site soils.
Treated Soil Performance Data. Table 2 presents treated soil performance data in
summary from our projects on PCBs. Appendix A contains a technical paper and USEPA
Site Demonstration Bulletin detailing the performance of a full-scale unit at the Re-Solve
Superfund site cleanup that clearly demonstrates the type of superior performance that can
be expected for the project. This unit was developed, designed, constructed and operated
by TD*X staff (i.e. Carl Palmer, Carl Swanstrom, and Gregg Meyers) who will directly
participate in the project on the MSR team. The MSR unit employs all of these process
steps as demonstrated by TD*X, but uses an indirect heated thermal processor that can
operate at 2.5 to 3 times greater than the production rate of the Re-Solve unit through
more efficient and higher rate heat transfer.
The Warren County project requirement for treated soil PCBs at less than 0.2 ppm is
technically feasible for the TDU. However, verifying this performance level may require
analytical methods development. In our experience, analytical laboratories can reliably
measure PCBs with a 0.5-2 ppm practical quantitation limit (PQL), depending on the matrix
5
and any interfering factors. Reliable PQLs at the 0.2 ppm level have not been available
in our experience.
Non-detect Dioxin Emissions. Air emissions from TD*X units have been measured at both
the full-scale and pilot-scale. In all cases, when dioxin precursors (PCB, and chlorinated
semi-volatiles) were present in the feed soil, these precursor compounds were not detected
above the method's practical quantitation limit (PQL) in our unit's process vent emission.
These emission factors for PCBs and semi-volatiles for TD*X units are over 10,000 times
lower than competitive thermal desorbers and comparable capacity incinerators.
Furthermore, dioxins were also at or near the PQL, but were below up-wind ambient air
samples' dioxin levels taken during the stack test.
During full-scale operations with PCB contaminated soil that also contained low levels of
dioxin, TD*X demonstrated dioxin emissions at 0.045 pg-2,3,7,8-TCDD(equiv.)/m3 while
venting only 37 scfm. This corresponds to an emission factor of 0.6 pg-TCDD/ton-soil.
This emission factor demonstrated by TD*X is tens of thousands times lower than that
demonstrated for competitive thermal desorbers available in the market. This feature
should derive benefits for NC-DENR in shorter review times for air and process permit
submittals, as well as better relations with the project stakeholders.
MSR and TD*X will deliver this same performance level to the Warren County project, but
with a more cost effective approach using a high capacity unit. This will provide value in
both cost and performance to the NC-DENR.
6
PERFORMANCE DATA -INDIRECT THERMAL DESORPTION UNITS
Midwest Soil and TD*X Associates
Table 2. Test Results -Dioxins/Furans, PCBs and Their Precursors
Media Concentration (ppm)
Constituent Feed Product Test Scale
Total PCB 50 <2 Lab-Pilot
Total PCB 66 <2 Lab-Pilot
Total PCB 97 <2 Lab-Pilot
Total PCB 114 <2 Lab-Pilot
Total PCB Sandy-Silty soil 25-13,000 <2 Full Scale
Total PCB 293 <2 Lab-Pilot
Total PCB 320 <2 Lab-Pilot
Total PCB 390 <2 Lab-Pilot
Total PCB 454 <2 Lab-Pilot
Total PCB 1,838 <2 Lab-Pilot
Total PCB 2,400 <2 Lab-Pilot
Total PCB 3,166 <2 Lab-Pilot
Total PCB 3,583 <2 Lab-Pilot
Total PCB Clay soil, Al(OH)x 25-36,000 <2 Full Scale
sludge
Total PCB Lagoon sludge 36,734 <2 Lab-Pilot
Total PCB Sump SludQe 102,000 <2 Pilot
7
•
APPENDIX A
• Technical Bulletins
•
HAZARDOUS WASTE OONT AMINA TED SOIL TREATMENT WITH THE
MIDWEST SOIL REMEDIATION, INC. HIGH CAPACITY INDIRECT
THERMAL DESORPTION UNIT
by Carl R. Palmer and Carl P. Swanstrom
SUMMARY. In 1998, Midwest Soil Remediation, Inc.
(MSR) shattered the soil production capacity barrier that
has limited indirect heated thermal desorbers. MSR
sustained operations near 50 ton/hr throughout a 30,000
ton cleanup project. This is a significant increase over
the current benchmark of I 0-15 ton/hr by several existing
commercial indirect heated thermal treatment systems.
Most significantly, MSR did this with a primary treatment
unit that is a true indirect heated processor, can heat soil
to temperatures of I ,000°F, or more ifrequired, and can
use a recovery style gas treatment system that is capable
of no-detectible air emissions of high hazard compounds
such as PCBs and dioxins.
BACKGROUND. Thermal desorption has been used
commercially since 1987 for the treatment of organic
chemical, petroleum hydrocarbon and mercury
contaminated soils and solids. Since 1990, MSR has
successfully operated direct heated thermal desorbers on
multiple sites, treating close to 1,000,000 tons of soil at
rates up to 120 ton/hr. Considering the complex issues
surrounding the treatment of hazardous organic chemicals
such as chlorinated hydrocarbons, pesticides, PCBs and
dioxins, MSR has focused their attention on bringing the
benefits of high capacity operation to highly regulated
contaminated site cleanup. The result is this high
capacity indirect thermal desorption unit (TDU).
TECHNOLOGY STATUS. The unit's first project
involved the treatment of 32,000 tons of solvent
contaminated soil. Even though the soil contaminants
were not PCBs or similar hard to remove compounds, this
project established outstanding production results that
clearly advance the use of thermal desorption for large
cleanup efforts. The soil had chlorinated solvents up to
1,000 ppm and was treated to less than IO ppb. This soil
was sandy and had moisture content of about I 0%.
Soil throughput was sustained at an average of near 50
ton/hr, with some days as high as 60-80 ton/hr. Soil was
heated to greater than 450°F. These conditions translate
to about 25 ton/hr capacity range for PCB/dioxin soil
treatment when the higher required soil treatment
temperature is factored in. These demonstrated
production rates by MSR set a new standard in indirect
heated thermal desorption, many times greater than prior
CLEAN
CARRIER GAS RECYCLE ~ PROCESS
NITROGEN
CONTAMINATED
SOLIDS
NON-CONTACT
FLUE GAS
t
HIGH CAPACITY
INDIRECT HEATED
THERMAL PROCESSOR
High Capacity Indirect TDU Process Flow
1 FILTERS VENT
RECOVERED .__ ___
OIL
CONDENSE D
WATER
CLEAN
SOLIDS
art systems used for PCBs, and will substantially reduce
the operating cost. When this primary unit is combined
with appropriate conventional off-gas treatment devices,
outstanding contaminant removal and air pollution
control performance are also achieved.
MSR, having demonstrated the effectiveness of the high
capacity indirect TDU, is applying it on hazardous waste
cleanup projects. MSR is also now reconfiguring the unit
for less volatile contaminants such as PCBs.
PROCESS DESCRIPTION. The basic process flow is
presented in the figure above. Contaminated materials
are fed continuously into an indirectly heated thermal
processor to desorb contaminants such as organic
chemicals and mercury. Treated solids are discharged to
a clean stockpile after cooling and wetting. Since neither
the contaminated solids nor the separated contaminants
ever contact the burner's flue gas, the products of
combustion are emitted to the atmosphere without
emission control devices.
The contaminants are transferred with an inert carrier gas
to the off-gas treatment system for condensation and
recovery. Full scale operations on PCBs have confirmed
that the contaminants are recovered and not degraded or
destroyed as they would be in an incinerator-type device.
In order to prevent unwanted emissions the system
pressure is kept negative. A portion of the treated off-
gas is purged, and the balance is returned to the dryer as
the carrier gas. This vent is at a very low purge gas flow
rate, typically less than I 00 scfm, allowing highly
efficient APC devices on it. The process vent gas can be
cleaned to any required emission standard. In most cases,
small filters are used to remove particulate matter and
hazardous organic air pollutants to well below the
national standards.
WASTE APPLICABILITY. The physical form of the
waste materials that can be managed in the high capacity
indirect TDU are: soil, sediments, sludge, filter cake,
geologic debris, and similar solids. Feeding material to
an indirect processor is particularly difficult. Not only
does the feed rate have to be controlled, but also air in-
leakage must be minimal for safety (to prevent burning
of the desorbed hydrocarbons). For this reason, a
specialized feed system is used that has been
demonstrated on all types of materials, ranging from sand
and gravel, to sticky cohesive "gumbo" clay, to oily
sludges. In all cases a controlled rate of feed has been
maintained, without unsafe air in-leakage.
Organic contaminants that are amenable to treatment
include essentially all regulated compounds, ranging from
PCBs, PAHs and dioxins to organic solvents, including
the volatile and semi-volatile organic compounds as well
as oils and petroleum products. The unit is especially
well applied to wood treatment waste with
pentachlorophenol because it addresses all of the many
performance issues on this most challenging application.
Manufactured gas plant (MGP) soils and residues are also
ideal because high production rates can be achieved
without regard to the sometimes very high contamination
level of these materials.
For specific projects such as lagoon sludge or process
filter cake treatment, contamination levels of 20%
hydrocarbons, or more can be treated. Because the
system is inerted, and combustion of the waste is not
allowed, this high level of contamination is safe. Oil
recovered from high hydrocarbon contamination has had
the characteristics of used motor oil: low ash content and
high heating value.
Mercury in all of its forms can be treated because the
TDU has the capability to operate at both the moderate
temperature required to desorb elemental mercury as well
as the much higher temperature required to thermally or
chemically reduce mercury compounds so that elemental
mercury can then be desorbed and recovered.
AIR EMISSIONS. Indirect heated thermal desorbers
have been operated at both the large pilot and full scale
with outstanding results with respect to air emissions. It
is important to note that air emissions control
performance varies widely among commercial indirect
heated thermal desorbers. The results described below
are for a properly configured off-gas recovery and
treatment system, as has been demonstrated by the
authors.
When PCBs, dioxins, mercury and similar highly
regulated compounds are present in the feed materials,
they are non-detectible in the air emission stream. This
result is possible even with percent levels of the
hazardous air pollutant in the feed. Multiple stack tests
have shown PCB "chute-to-stack" removal efficiencies
greater than 99. 999999%; over 500 times better than EPA
guidelines for PCB incinerators. This high control
efficiency is combined with an extremely low air
emission flow rate from the TDU to yield an unequaled
low total organic emission rate; measured at less than 0.4
gram/day when feeding PCB contaminated soils. This
result is over I 0,000 times better than comparable thermal
desorbers that have been used at CERCLA remediation
sites.
PERMITTING. The high capacity indirect TDU is a
"true" indirect unit that has a completely indirect-fired
heat source in the primary desorption chamber, operates
at relatively low solids temperatures, and uses a recovery
style air pollution control system. Recovered treatment
residuals are managed separate from the thennal desorber
unit.
Substantial USEPA pennit doctrine has been developed
that classifies the high capacity indirect TDU as a
"miscellaneous unit." With respect to PCBs regulated by
TSCA, the unit is considered an alternative treatment
technology of the physical separation type. Both of these
detenninations result in favorable review of pennit
applications or their equivalent under Federal Superfund
or State site cleanup programs. Numerous projects have
received straightforward and relatively simple review and
approval for operations. This can be contrasted to similar
sites that have experienced costly multi-year or project
ending approval delays when incinerator-type devices
have been the chosen remedy.
SITE REQUIREMENTS. The high capacity indirect
TDU is a transportable system that ships on about ten to
twelve trailers. The footprint of the entire system is about
110 ft x 130 ft. It can be installed on a finn, level base
that is capable of supporting equipment loads of 2,500
psf.
The liquid handling equipment is installed on skids or
trailers that have their own secondary containment
provisions that meet strict EPA RCRA and TSCA spill
prevention requirements. The unit can be processing
waste within three weeks of arrival on site. It's capacity
varies depending on the soil contaminant. For PCBs and
similar hard to remove compounds, the capacity is about
25 ton/hr. If easier to remove compounds such as
solvents or pesticides are present, capacity of 50 ton/hr or
more can be achieved.
The unit operates on a 3-phase, 460-V power supply of
less than 500 kVA capacity. The dryer furnace bums
gaseous fuel such as natural gas or LPG (propane). The
maximum fuel firing rate is 72 million BTU/hr, but for a
15% moisture content PCB soil the fuel consumption rate
would be about only 35 million BTU/hr.
All water requirements are carefully balanced within the
unit, and there is not nonnally a water discharge
requirement. Because water is used to cool the treated
soil, there is nonnally a makeup water requirement to
balance this use, which can be in the range of I 0-20 gpm.
It is not necessary for this to be potable ( drinking) water,
therefore, non-contaminated surface water or other
process water available at the site can be used.
TREATMENT COST. MSR will be able to perfonn
this service substantially below the historic market price.
From 1989-1997, according to many sources, the market
price for indirect thennal desorption of PCB
contaminated soil has been in the $125-225/ton, on a
"pile-to-pile" basis. Some projects have been performed
for $300/ton or more. Project size needs to be greater
than 30,000 tons of soil for the above pricing to be valid.
The cost of operating an indirect thermal desorber at 25
ton/hr is less than 50% of that of operating a comparable
unit at 8-10 ton/hr. This is a significant result.
Through the '90s, many organic contaminated sites have
had thennal desorption selected as the remedy, based on
the favorable pennitting environment for these units.
However, the cost difference between "true" indirect
thennal desorbers and alternatives such as off-site landfill
disposal or direct fired thennal desorption treatment have
caused remedial project managers to reluctantly select
these alternatives based on significant cost differences.
MSR can now offer on-site thennal desorption with this
high capacity indirect unit, using a recovery gas system,
for a similar or lower cost than the less desirable
alternatives.
A second benefit of using the high capacity indirect TDU
is a reduction in project schedule and the associated
project indirect costs, such as: project management,
support facility operations, EH&S program operations
and similar activities that must be perfonned any day that
field operations are conducted at these sites. Cutting the
project schedule for field treatment operations by a factor
of two or more has a corresponding reduction in indirect
expenses.
AUTHOR INFORMATION. Carl Palmer is the
director of the thermal process group at TD*X
Associates. Thermal desorption technology development,
lab and pilot testing, and commercial unit field services
are the core activities of TD*X. Mr. Palmer is the co-
author of two books and two national standards on the
use of thermal desorption for hazardous waste treatment.
Carl Palmer, P.E.
TD*X Associates
P.O. Box 13216
Research Triangle Park, NC 27709
ph (9 I 9) 468-1266 FAX [phone]
E-mail: [e-mail]
Carl Swanstrom is a chemical engineer at the DOE's
Argonne National Laboratory in Illinois. Assessment and
implementation support of hazardous and radioactive
waste treatment technologies are his key activities. At
Argonne, he has led a large scale pilot study on the use of
direct fired thermal desorption for pesticide contaminated
soils at Rocky Mountain Arsenal. He is currently
involved in the development of a soil washing process for
radionuclides with Russian scientists in Moscow, and a
chemical extraction process with a US firm. He is also
supporting the DOE's TechCon program that connects
technologies and services in the private sector with DOE
needs for remediation. He also functions as a private
consultant for focused new technology efforts.
Carl Swanstrom
Argonne National Laboratory
9700 S. Cass A venue, Argonne, IL 60439
ph [phone] FAX [phone]
E-mai I: earl_ [e-mail] I .gov
Mr. Swanstrom and Mr. Palmer were the primary
developers of both the X*TRAX®1 and V AC*TRAX
thermal desorption technologies while at Chemical Waste
Management, Inc. The combined application experience
of these two technologies, involving hundreds of waste
materials and over 140,000 tons of field remediation
operations, provides the technical foundation for using
the MSR high capacity indirect TDU.
Midwest Soil Remediation, Inc. MSR is the owner and
operator of the high capacity indirect TDU.
Midwest Soil Remediation, Inc.
1480 Sheldon Drive
Elgin, IL 60120
ph [phone] FAX [phone]
1. X*TRAX is a registered service mark of Chemical Waste Management, Inc.
&EPA
United States
Environmental Protection
Agency
EPA/540/MR-93/502
February 1993
---------------
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION ___ -~~-------~------~
Demonstration Bulletin
X*TraxTM Model 200 Thermal Desorption System
Chemical Waste Management, Inc.
Technology Description: The X*TRAX™ Model 200 Thermal
Desorption System developed by Chemical Waste Management,
Inc. (CWM), is a low-temperature process designed to separate
organic contaminants from soils, sludges, and other solid media.
The X*TRAX™ Model 200 is fully transportable and consists of
three semitrailers, one control room trailer, eight equipment skids,
and various pieces of movable equipment. The equipment re-
quires an area of about 125 ft by 145 ft. The system is shown in
Figure 1 and is described below.
The X*TRAX™ system is a thermal and physical separation pro-
cess; it does not involve incineration. Contaminated solids are
fed into an externally heated rotary dryer where temperatures
range from 750 to 950 °F. Evaporated contaminants are removed
by a recirculating nitrogen carrier gas that is maintained at less
than 4% oxygen to prevent combustion. Solids leaving the dryer
are sprayed with treated cooling water to help reduce dusting
when the treated solids are returned to their original location and
compacted in place. The nitrogen carrier gas is treated to remove
and recover dust particles, organic vapors, and water vapors.
An eductor scrubber removes dust particles and 10% to 30% of
the organic contaminants from the carrier gas. Scrubber liquid
collects in a phase separator from which sludge and organic
liquid phases are pumped to a filter press, producing filter cake
and filtrate. The filtrate is then separated into organic liquid and
water phases. Most contaminants removed from the feed solids
are transferred to the organic liquids or the filter cake. The filter
Carrier Gas I r--------------~-------7
Makeup ~
Water
Dry
Solids
,----L-..,.---. CarrierGas J
Eductor _/_
,----11~ Scrubber --
Filtrate
Filter
Press
Filtrate
Tank
Rgure 1. Diagram of X'Trax system.
Product
Cooler
Treating
Cooling Water .------,
Condensers
Condensate
Activated
Carbon
Canister
Condensed
Water
High
Temperature
Reheater
Mist c,:._~!__ ~ Eliminator .._, ~,.
I
I
Particle Nitrogen
Filter Tank
Key
Activated --Liquid Flow
Carbon
-Solids Row
--Gas Flow
[Q] Input
0 Output
@ Printed on Recycled Paper
~e is typically blended batchwise with feed solids and repro-
cessed in the X*TRAX™ system, while the concentrated organic
liquids are typically treated or disposed of offsite.
Carrier gas exiting the scrubber passes through two condensers
in series, where it is cooled to less than 40°F. The condensers
separate most of the remaining water and organic vapors from the
gas stream. Organic vapors are recovered as organic liquids;
water is treated by carbon adsorption and either used to cool and
reduce dusting from treated solids, or treated and discharged.
About 5% to 10% of the gas exits the system through a process
vent, passing through a particle filter and carbon adsorption sys-
tem before being discharged to the atmosphere. The volume of
gas released by the X*TRAX™ system is about 100 to 200 times
less than the amount released by an equivalent capacity incinera-
tor.
Waste AppllcabllHy: CWM reports that the X*TRAX™ system
can process a wide variety of solids at feed rates up to 7.5 tons
per hour (tph). The technology is most effective for solids with a
moisture content of less than 50%. Screening of material greater
than 2.25 in. in size may be required for some applications.
Bench-, pilot-, and full-scale X*TRAX™ systems have been used
to treat solids contaminated with the following wastes: polychlori-
nated biphenyls (PCB); halogenated and nonhalogenated sol-
vents; semivolatile organic compounds (SVOC); polynuclear aro-
matic hydrocarbons; pesticides; herbicides; fuel oils; benzene,
toluene, ethylbenzene, and xylenes (BTEX); and mercury. The
X*TRAX™ system has also treated Resource Conservation and
Recovery Act (RCRA) hazardous wastes to meet Land Disposal
Restrictions (LDR) treatment standards. RCRA wastes treated by
X*TRAX™ include petroleum refinery wastes (K048 through K052)
and multisource leachate treatment residues (F039).
Demonstration Results: The X*TRAX™ SITE demonstration
was conducted in May 1992, after a proof-of-process test at the
Re-Solve Superfund Site in North Dartmouth, MA. The system is
being used to treat approximately 35,000 tons of soil and sedi-
ment contaminated with PCBs at the site. For this application, the
soil is screened to remove particles larger than 1 in. in size.
During the SITE demonstration, about 215 tons of soil were
treated at an average feed rate of 4.9 tph, a residence time of 2
hr, and an average treated soil temperature of 732°F. PCB con-
centrations in contaminated soil ranged from 181 to 515 milli-
grams per kilogram (mg/kg). Average flow rates for the carrier gas
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
EP A/540/M R-93/502
and process . vent gas were 700 and 37 actual cubic feet per
minute (acfm), respectively.
The demonstration included three identical tests, each lasting 6
hr. During each test, solid, liquid, and gas samples were col-
lected from feed soil, treated soil, filter cake, filter press filtrate,
condensed aqueous liquids, water used to wet treated soil, and
process vent gases before and after activated carbon treatment.
Condensed organic liquids were collected before the start of the
first test and after completion of the third test. Extensive analyses
were performed under rigid quality assurance procedures. Key
findings from the X*TRAX™ SITE demonstration are summarized
below:
• X*TRAX™ successfully removed PCBs from feed soil and met
the site-specific treatment standard of 25 milligrams per kilo-
gram (mg/kg) for treated soils. PCB concentrations in all
treated soil samples were less than 1.0 mg/kg and the average
concentration was 0.25 mg/kg. The average PCB removal
efficiency was 99.9%.
• Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated
dibenzofurans (PCDF) were not formed within the X*TRAX™
system.
• Organic air emissions from the X*TRAX™ process vent were
negligible (0.4 grams/day). PCBs were not detected in vent
gases.
• X*TRAX™ effectively removed other organic contaminants
from feed soil. Concentrations of tetrachloroethene, total re-
coverable petroleum hydrocarbons, and oil and grease were all
reduced to below detectable levels in treated soil.
• Metals concentrations and soil physical properties were not
altered by the X*TRAX™ system.
For-Further Information:
EPA Project Manager:
Paul R. dePercin
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
[phone]; FAX [phone]
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
THERMAL DESORPTION OF PCB-CONT AMINA TED SOIL
AT THE RE-SOLVE SUPERFUND SITE
Richard J. Ayen, Ph.D.
Carl R. Palmer
Ru.st Federal Services Inc.
100 Technology Drive, Anderson, SC 29625
[phone]
Paul Matz
Gregg S. Meyers
Ru.st Remedial Services Inc.
7250 West College A venue, Palos Heights, IL 60463
[phone]
ABSTRACT
Full-scale operation of the X"'l'RA)l thermal
desorption process was initiated in June, 1993 at the
Re-Solve Superfund site in North Dartmouth,
M~husetts. This was preceded by a very successful
full-scale proof-of-process pilot demonstration in
May, 1992. The X"'TRAX system separates organic
contaminants from soil and sludge by heating the
solids in a sealed, indirectly fired rotary dryer. The
Re-Solve site was the location of a solvent recycling
facility, and 50,000 tons of PCB contaminated soil
required treatment by the X"'TRAX unit. Although
the site treatment standard was 25 ppm, the soil was
routinely treated to less than 2 ppm PCBs. PCB levels
in the feed soil ranged from 25 ppm to 13,000 ppm,
with the average being from 300 to 700 ppm. The
X"'TRAX unit was operated at continuous feed rates of
up to 11 tn./hr. and routinely achieved an on-line
factor of over 80 % . A USEPA Superfund Innovative
Technology Evaluation (SITE) demonstration was also
carried out in May, 1992. For this demonstration,
PCB levels in the feed ranged from 181 to 515 ppm;
treated soil samples all contained less than 1 ppm
PCB, with an average of 0.25 ppm. Soil treatment
progressed as planned at Re-Solve, and treatment
operations were concluded in July, 1994. In early
1995, preparations were begun to move the system to
the Sangamo Superfund site in South Carolina, again
for the remediation of PCB-contaminated soil.
INTRODUCTION
Rust Remedial Services Inc. offers a low temperature
thermal desorption process for the removal of organic
contaminants from soils, sludges and filter cakes. The
X~ process has been patented. It is capable of
removing a wide variety of contaminants, including
PCBs, solvents, pesticides and pesticide intermediates,
as well as mercury (1). The development of the
process has been documented previously (2, 3). This
process was selected for the remediation of PCB-
contaminated soil at the Re-Solve Superfund site in
North Dartmouth, Massachusetts.
SITE HISTORY
The Re-Solve Superfund site is located in a rural area
in southeastern Massachusetts on a 11.5 acre parcel.
The site was operated as a waste chemical reclamation
facility from 1956 to 1980. A variety of haz.ardous
materials were handled at the site including PCB oil,
waste oils, solvents, organic liquids, organic solids,
acids, alkalies, inorganic liquids, and inorganic solids.
In 1981 all buildings, drums, and debris were
removed by the owner, and the site was covered with
an unknown quantity of sand. The contents of the
four on site lagoons were not removed, and the
building foundations along with several loading and
unloading pads were left in place. Later that year the
Massachusetts Department of Environmental Quality
Engineering submitted a request to the EPA that the
site be placed on the National Priorities List (NPL).
The site was placed on the NPL in December of 1982.
Over the next two years a number of site
investigations and studies were conducted by the EPA,
including a Remedial Investigation and Feasibility
Study (RI/FS), leading to a Remedial Action Master
Plan (RAMP) and a Record of Decision (ROD). The
investigations characterized and identified the sources
of contamination, as well as defined the scope of
remedial action. The remedial action that was
implemented identified approximately 15,000 cubic
yards of waste which required disposal. The remedial
action was carried out under the direction of the U.S
Army Corps of Engineers from September of 1984 to
January of 1987.
During the removal acttv1ttes, extensive soil
contamination was detected which went beyond the
scope of the remedial action defined in the original
ROD. Additional testing was done, and these tests
showed that PCB contamination existed at
concentrations greater than 50 ppm in soils up to ten
feet below the seasonal low groundwater. An off-site
RI/FS that was conducted during the removal activities
indicated that soil and sediment contamination by
PCBs was present in the off-site wetland areas as well.
In February of 1987 a supplemental on-site remedial
investigation was completed to address the additional
contamination that was detected. In September of
1987 the EPA issued the final ROD which included
two phases of remediation; the Source Control
Remedy (SCR) which focused on the remediation of
soil in the unsaturated z.one, and the Management of
Migration which focused on the remediation of
groundwater.
In 1989 the EPA, the Massachusetts Department of
Environmental Protection, and over 200 potentially
responsible parties (PRPs) signed a consent decree
requiring the PRPs to direct and help pay for the clean
up work specified in the ROD. In October of that
year Rust was awarded the contract for the SCR.
The supplemental ROD identified PCB-contaminated
soils and sediments as posing the greatest
environmental risks from the Re-Solve site. The SCR
phase of the project called for the excavation of more
than 20,000 cubic yards of contaminated soil and
sediment, on-site treatment of what is found to be
contaminated, and finally placement of the clean
material back on site. The cleanup requirement for
soils removed from the unsaturated z.one prior to
replacement was 25 ppm or less; for the soils and
sediments removed from the wetland areas, the
requirement was 1 ppm or less.
The supplemental ROD also specified that the soil and
sediments be treated in a "mobile dechlorination
facility", and required that a "practical scale" (proof of
process) demonstration of the dechlorination
technology be performed prior to the full scale
treatment. In order to meet all of the requirements of
this "practical scale" demonstration Rust elected to
mobilim it's X"'TRAX thermal desorption process,
and demonstrate the dechlorination process on the
concentrated PCB waste stream which would be
recovered by X"'TRAX.
In June of 1990 Rust began preparation of the site.
The first major undertaking involved characterizing
the site to define the areas of PCB contamination. The
data generated during the original SCR was found to
be inadequate, so additional sampling was done. The
site was extensively sampled, and all of this
information was then used to generate a computer
model which delineated the contaminated areas of the
site.
The X"'TRAX and dechlorination units were brought
on-site in March of 1992. All of the equipment was
assembled and tested in five weeks. The proof of
process test was performed over a ten day period in
May of 1992. This was immediately followed by a
USEPA Superfund Innovative Technology Evaluation
(SITE) demonstration.
One of the major post-demonstration decisions, was to
eliminate the requirement for dechlorination of the
waste. While the technology was successful in
treating the waste, it generated additional waste to be
disposed of. In an effort to minimim the amount of
waste being shipped off site for incineration, the
requirement was removed.
In June of 1993, almost a full year after the pilot
demonstration, approval to begin the full-scale
remediation was secured. The full-scale remediation
phase proceeded without interruption until July of
1994 when the last of the 50,000 tons was treated by
the X"'TRAX unit. Other than scheduled maintenance
outages, the site was operational for 24 hours a day,
7 days a week.
The final phase of the SCR, the demobilization of the
equipment began immediately upon completion of
thermal processing in July of 1994. This phase of the
project was projected to be completed in the fall of
1994, paving the way for the start-up of the
Management Of Migration Phase. This phase of the
project is expected to last for the next ten to fifteen
years.
PROCESS DESCRIPTION
The X*TRAX™ Model 200 Thermal Desorption
System is a low temperature desorption process
designed to remove organic contaminants from soils, sludges, and other solid media. The Xlfc'fRAX Model 200 is
fully transportable and consists of a rotary dryer, gas treatment system, liquid processing system, one control room
trailer and various pieces of moveable equipment. The equipment can be assembled and staged in an area of about
125 ft. by 125 ft . The Xlfc'fRAX process flow is shown in Figure 1 and is described below.
The X*TRAX system is a thermal/physical separation process. Contaminated materials are fed into an externally
heated dryer in which water and organic contaminants are volatilized from the solids. Processed solids exit the dryer
at between 450 and 850°F and are cooled with water to eliminate dusting. The treated solids can be returned to their
original location and compacted in place. At Re-Solve, consistent operation was achieved with the product
temperature between 500 and 750°F.
The organic contaminants and water vapor that are volatilized from the solids are transported out of the dryer by an
inert carrier gas. The carrier gas is ducted to the gas treatment system, where it passes through a cyclone (for fine
particulate removal) and then a high-energy eductor scrubber. The scrubber removes high boiling point organic
compounds, cooling the gas to 180°F. Carrier gas exiting the scrubber then passes through two condensers in series
where it is cooled to less than 50°F.
Most of the conditioned carrier gas is reheated and recycled to the dryer. Approximately 10 percent of the carrier
gas is vented through a high efficiency particulate air (HEPA) fi lter and a carbon adsorption train before it is
discharged. Because indirect firing and carrier gas recycle are used, emissions from the process are very small; only
30-50 cubic feed per minute (cfm). This discharge (600 times less than an equivalent capacity incinerator) helps
maintain a small negative pressure within the system and prevents the release of potentially contaminated gases.
Makeup nitrogen is added to the system to keep oxygen concentrations low (typically less than 1 % ). This is done to
insure that no combustion takes place within the system.
X*TRAX: PROCESS FLOW DIAGRAM
ORGANICS
SLUDGE
DRY PRODU CT
Figure 1
MAKEUP
CONDEN SATE
STOR AGE
ROTAR Y DRYER
VENT
GAS
HIGH T
REHEAT
The X"'TRAX Model 200 full-scale system was
completed in late 1989. This unit is completely
transportable and can be set up on site in less than four
weeks. Site requirements are for a firm, level surface
to set the equipment. Housekeeping pads are then
poured to facilitate operations. Propane fuel and
nitrogen are provided from storage tanks. The unit
can be fired on natural gas if it is available. Electrical
service of 700 amps, 480V, three phase is required
and can be provided by a diesel generator if necessary.
The unit is completely self contained and, if required,
can derive essentially all of its process water
requirement from the soil being treated.
PROOF-OF-PROCESS DEMONSTRATION TEST
The X"'TRAX Model 200 was mobilired to the Re-
Solve site in late March, 1992. Within 5 weeks the
Model 200 and the pilot-scale dechlorination system
were installed and functionally tested, confirming the
mobility of the equipment. The proof-of-process pilot
demonstration test was performed over a ten day
period in May, 1992. During the demonstration test
over 500 tons of PCB-contaminated soil were
processed through the X"'TRAX unit. The PCBs
removed from the contaminated soil by the X"'TRAX
system were concentrated into an organic liquid which
was then processed through the dechlorination system.
The performance of the X"'TRAX unit was
outstanding. Treated soil had PCB residual levels
consistently below 2 ppm, well below the 25 ppm
treatment standard established for the site. This
excellent performance was achieved while the unit was
being operated at nearly 160 ton/day, 20 percent more
than the design throughput capacity.
A U.S. EPA Superfund Innovative Technology
Evaluation (SITE) demonstration was performed in
conjunction with the proof-of-process demonstration
test in May, 1992. Extensive samples were taken to
fully characteri:ze the operation of the X"'TRAX unit.
Three sampling intervals of six hours each were
employed over a two day period. Samples were taken
of the feed and treated soil as well as the aqueous,
organic, and solid residuals from the process. The air
emissions from the process vent were also sampled
before and after the carbon adsorption units. PCBs,
volatile organics, semi-volatile organics, and
PCDD/PCDFs (dioxins and furans) were all analytical
parameters. The results were reviewed by the U.S.
EPA' s Center for Environmental Research Information
and summarired in a demonstration bulletin (4).
During the SITE test, PCB levels in the feed ranged
from 181 to 515 ppm. All of the treated soil samples
had less than 1 ppm PCB, and the average was 0.25
ppm, demonstrating a PCB removal efficiency of
99.9%. No PCB's were detected in the process vent.
The SITE demonstration results indicated
PCDD/PCDFs were not formed within the X"'TRAX
system. Even though PCDD/PCDFs were present at
low levels in the feed soil, they were not detected in
the process vent. Total hazardous air pollutant
emissions from the unit were negligible at 0.4
gram/day.
FULL SCALE PRODUCTION
Full scale production began on June 21, 1993 and was
completed on July 16, 1994. During the first month
of full-scale operation, data were collected so that a
detailed mass balance could be calculated. This was
the only time other than during the initial site
characterization that samples of the untreated soil were
collected. The results of that mass balance are
included in Table 1, and demonstrate complete
recovery of the PCBs that were fed to the unit.
TABLE 1
MASS BALANCE RESULTS
PCBINPUT
PCB OUTPUT
Treated Soil
Primary Phase Separator Filter Cake
Condensate Phase Separator Filter Cake
Untreated Condensate Water
Condensed Oil in Storage Tank
Condensed Oil in System
Total PCBs
Percent Recovery of PCBs
7914 Pounds
63 Pounds
3121 Pounds
2384 Pounds
565 Pounds
1511 Pounds
50 Pounds
7694 Pounds
97%
Figures 2 and 3 show system availability and
throughput, respectively, for June, 1993 through July,
1994, the last month of operation. All throughput
tonnages in Figures 2 and 3 have been adjusted to a
1 % moisture basis. System availability was low
during the first two months of operation, primarily
due to mechanical problems with the product handling
system. Several modifications were made to the
system between June and November of 1993, which
resulted in gradual improvement in system availability
and throughput.
In December, the system went through a major
turnaround, and several modifications were
implemented which subsequently provided increased
reliability. After this turnaround, system availability
was consistently above 80 % , peaking at 93 % for the
month of March, 1994.
Monthly throughput trended upward with availability,
with the exception of January, February and March of
1994, when cold winter weather and precipitation
reduced treatment rates. Daily throughput rates
peaked during June, 1994, the last full month of
operation, when 5,885 tons were treated, for an
average 195 tons per day on a 1 % moisture basis. If
the system availability of 90 % is taken into account
and the throughput rate adjusted to the as-fed average
moisture content of 15.5%, the daily throughput was
250 tons per available machine day. This well
exceeds the original design goal of 125-150 tons per
available machine day. In early 1995, planning was
begun to move the system to the Sangamo Superfund
site in Pickens, South Carolina. The project will
involve the removal of PCBs from ~ 50,000 tons of
soil.
CONCLUSIONS AND KEY RESULTSJ.
"Proof of Process" Test and "SITE"
Demonstration Test
Note: These conclusions were made by the EPA
and reviewed by the U.S. EPA's Center for
Environmental Research.
• X"'TRAX successfully removed PCBs from feed
soil and met the site-specific treatment standard
of 25 milligrams per kilogram (mg/kg) for
treated soils. PCB concentrations in all treated
soil samples were less than 1.0 mg/kg and the
average concentration was 0.25 mg/kg. The
average PCB removal efficiency was 99. 9 % .
• Polychlorinated dibenzo-p-dioxins (PCDD) and
polychlorinated dibenzofurans (PCDF) were not
formed within the X"'TRAX system.
• Organic air emissions from the X"'TRAX
process vent were negligible (0.4 grams/day).
PCBs were not detected in vent gases.
• X"'TRAX effectively removed other organic
contaminants from feed soil. Concentrations of
tetrachloroethene, total recoverable petroleum
hydrocarbons, and oil and grease were all
reduced to below detectable levels in treated
soil.
• Metals concentrations and soil physical
properties were not altered by the X"'TRAX
system.
2. Full-Scale Production Highlights
• On its first project, the availability of the
X"'TRAX thermal desorption system reached a
peak level of 93 % during March, 1994.
Availability was consistently at 80% or above
during the final six months of operations.
• Daily throughput rates of 250 tons per day were
consistently demonstrated, with peaks in excess
of 300 tons per day and no appreciable drop in
the treatment standard.
• The avepage of all the treated soil samples was
2.9 ppm for PCBs. This corresponds to overall
removal of PCB efficiency for the entire project
of99.2%. (Based on an average contamination
level of 365 ppm from the site characterization
data).
REFERENCES
1. Palmer, C., Experience with the X"'TRAX:
Thennal Desorption System, Presented at the
Conference on Remediation of Contaminated
Sites, Vancouver, British Columbia, May,
1993.
2. Swanstrom, C., Thermal Separation of Solids
Contaminated with Or~anics, Presented at
HazMat '91 West, Long Beach, California,
November, 1991.
3. Swanstrom, C. Determinin~ the Applicability of
X*TRAX: for On-Site Remediation of Soil
Contaminated with Or~anic Compounds,
Presented at HazMat Central '91, Rosemont,
Illinois, April, 1991.
4. Demonstration Bulletin: X"'TRAX Model 200
Thermal Desorption System, USEP A,
EPA/540/MR-93/502, February, 1993.
100%
90%
80%
-70%
~ 60% ~ :a 50%
~ 40% "iu > < 30%
20%
10%
0%
Figura 2
6,000
-5,000 cu ... := -Cit ·s 4,000 ~
'i/1. ---;;; 3,000
C ~
I ftl cu
2,000
t= 1,000
Figura 3
---
X*TRAX Availability
Re-Solve Superfund Site
6/93 8/93 1 0/93 12/93 2/94 4/94 6/94
7/93 9/93 11 /93 1 /94 3/94 5/94 7 /9~
Month
X*TRAX Treated Tons
Re-Solve Superfund Site
6/93 8/93 10/93 12/93 2/94 4/94 6/94
7 /93 9/93 11 /93 1 /94 3/94 5/94 · 7 /94
Month
•
•
•
APPENDIX B
Photographs
Midwest Soil Remediation, Inc. High Capacity Indirect Thermal Desorption Unit.
Operated at 45-50 ton/hr in 1998
TD*X Associates. Indirect Heated Thermal Desorber used for Re-Solve
Superfund Site Cleanup, 1992-1994.