U.S. Environmental
Protection Agency
Office of Solid Waste and
• Emergency Response
Technology Innovation Office
EPA/540/M-90/008 No. 1 July 1990
Ssi! W9
The applied technologies journal for Superfund removals and remedial actions and RCRA corrective actions
Welcome §0
Tech Trends
Focus ort innovations in
cleanup action
t comes as no great surprise that
Regional personnel involved in
CERCLA removals or remedial
actions on RCRA corrective actions
canbecome overwhelmed with
information. Some is good, some is
problem is, who's got time to keep/'"
upwitaitail?
Over the pastcoupte of years,
OSWER and QRO laboratories
have increased {heir efforts devoted
to getting the word out. The
PSC/KPMSapport Program, a
number of electronic databases, ami
more technical conferences have all "
added, to the amount of information
available to folks out ia the field.
Recent surveys all highlight the fact
that people need guidance through
the forest of information,
Tech Trends will bring current
information on hazardous waste
treatment innovations to Regional
parts, and: their contractors. Tech
Trends will addftss innovative uses
ing bureaucratic obstacles to the use
of innovative technologies, and the
transfer of innovative Superfund
cleanup technologies to RCRA
corrective actions.
o
Biological Cleanup of TCE, DCE,
and YC in Ground!
Water
by Marion Scalf
Roberts. Kerr Laboratory
TCE, DCE,
VC
Btoremedlatlon
Ground
Watar
'rdinarily, trichloroethylene (TCE), cis- and trons-
dichloroethylene (DCE), and vinyl chloride are not biodegraded in oxygenated
ground water. Recent advances in biotechnology, however, offer an attractive
alternative to physical or chemical treatment of water contaminated with these
substances. In 1984, Dr. John Wilson of EPA's Robert S. Kerr Environmental
Research Laboratory (RSKERL) in Ada, Oklahoma, discovered that microorganisms
that degrade methane contain an enzyme that fortuitously transforms TCE, DCE, and
vinyl chloride to the corresponding epoxides. The epoxides decompose in water to
other compounds that are easily decomposed by ordinary microorganisms. In
laboratory studies, the chlorinated aliphatics were mineralized completely to CO2 and
water.
In order to demonstrate the process in a field situation, RSKERL entered into a
cooperative agreement with Stanford University, and, in cooperation with the U.S.
Navy, demonstrated biological removal of TCE, cis- and trans- DCE, and vinyl
chloride in a shallow, semi-confined, sand and gravel aquifer. The demonstration
(see Biological Cleanup, page 3)
Superfund Bio remediation RODs:
Waste Source Analysis
H Pesticide (2)
H Petrochemical (3)
£3 Wood Preserving (9)
Q] Manufacturing (2)
Q Chemical Formulation and Use (3)
11 Commercial Waste Disposal (2)
-------
New for the Bookshelf
Directory of
Technical Support Services
• inding the right source of technical
assistance for Superfund sites has just
gotten a lot easier, says Walt Kovalick,
Director of OSWER's Technology
Innovation Office.
A new directory, Technical
Support Services for Superfund Site
Remediation, is organized by source of
information and contains descriptions,
contacts, phone numbers, and cross-
references to engineering programs,
risk assessment information, ground
water assistance, a number of easily
accessible databases, several major
technical publications, and other
sources.
While TIO hopes to have a
directory in everyone's hands by
summer, Dr. Kovalick encourages
people to contact ORD Publications at
FTS 684-7562 or 51.3-569-7562 if they
haven't received a copy.
««nri«M far tmrnmlmmi
SttcB*
Soil Incineration at
Baird and McGuire
by Michael Royer, Donald Oberacker,
and Maria Richards
Risk Reduction Engineering Laboratory
Pesticides,
As,Pb
Soil
Incineration
Soil
Recent SPA publications are available
from ORD's Center for Environmental
Research Information In Cincinnati.
You can order thorn electronically on
the OSWER Electronic Bulletin Board
or dlrefitff from CERf. To contact
CERI's Publfcattona Untt, call FTS 6IJ4-
7562, or 513^569-7582, You must have
the EPA report number or the exact title
of the document
Selected Alternative and Innovative
Treatment Technologies for Corrective
Action and Site Remediation. Osts EPA
publications on technology survey reports,
treatability studies, treatment technologies,
guidance, technical support, international
surveys, and databases.
Publication number EPA/540/8-90/003.
Technological Approaches to the
Cleanup of Radiologically Contaminated
Superfund Sites. Identifies technologies
for the control and remediation of radioac-
tive contamination at Superfund sites.
Technologies include: stabilization/
solidification, vitrification, chemical
extraction, and physical separation. On- and
off-site disposal methods are also dis-
cussed.
Publication number EPA/540/2-88/002.
• he Risk Reduction Engineering Laboratory (RREL) investigated die fate of metals and organics during the incineration of
contaminated soil from a former pesticide batching and mixing plant
As part ftf ORD's Superfund Technical Assistance Remedial Technology (START) program, the study was done at the
laboratory's Incineration Research Facility (IRF) to assist Region I in defining conditions for successful treatment of soils at the
Baird and McGuire (B&M) site in Holbrook, MA.
RREL conducted an IRF treatability test on soil from the site. The test consisted of a series of muffle furnace tests and a series
of rotary kiln incineration tests on soils contaminated with pesticides, arsenic (As), and lead (Pb). (Soil samples were chosen from
locations on the site which did not contain dioxins, due to permit limitations at die IRF.)
The muffle furnace testing showed that the volatilization of As and Pb was concentration dependent i.e., as the soil metal
concentration Increased the percentage of volatilization also increased. The rotary kiln incinerator tests were performed on blended
B&M site soils, which averaged 85 ppm As, 20 ppm Pb, 54 ppm DDE, 70 ppm methoxychlor, 228 ppm ODD, and 334 ppm DDT.
The following conclusions were drawn from the pilot scale incineration test program:
• Both As and Pb partitioning to the ash decreased as kiln temperatures increased.
• Kiln ash Pb was not significantly teachable via the Toxicity Characteristic Leaching Procedure (TCLP).
• Kiln ash As was significantly less TCLP-leachable for high kiln excess air (high oxygen content and moderate temperature).
(see Soil Incineration, page 3)
-------
Soil Incineration
(from page 2)
Extrapolation of the incineration
test results suggest that soil with As
levels as high as 1200 mg/kg could be
incinerated to give a kiln ash with a
TCLP-leachate concentration of less
than 5 mg/L provided suitable
operating conditions were main-
tained. No detectable levels of
organics were found in any of the
residual samples that were sampled,
extracted, and analyzed using
approved EPA methods.
For additional information on
START assistance at the B&M site
contact Michael Royer at FTS-340-
6633. For additional information on
the incineration testing on B&M
soils, contact Marta Richards at FTS-
684-7645.
Biological Cleanup
(from page 1)
was conducted at Moffett Naval Air
Station located near the southern end
of San Francisco Bay. Water was
extracted from the aquifer and
amended with oxygen, methane, and
the chlorinated hydrocarbons, then
reinjected into the aquifer. The
concentration of the chlorinated
organic contaminants was determined
in water from monitoring wells 1.0m,
2.2m, and 3.8m down-gradient from
the injection well. The ground water
velocity was near 2 m/day.
The aquifer apparently already
contained organisms that use methane.
It was not necessary to inoculate the
aquifer with fobign organisms, but it
was necessary to supplement the
aquifer with nitrogen or phosphorus.
After complete acclimation, the
microorganisms removed more than
95% of the vinyl chloride, more than
90% of the trans- DCE, more than
45% of the cis- DCE, and about 20%
oftheTCE.
For more information, contact
Dr. John Wilson at FTS-743-2259 or
405-332-8800
SITE Subjects
Demonstration of
Mierofiltration
Technology
by John Martin
Risk Reduction Engineering Laboratory
Metals
Micro-
filtration
Ground
Water
• he most recently completed field demonstration project under the SITE Program is
the effort involving E.I. DuPont de Nemours and Co. and the Oberlin Filter Com-
pany. The field work was undertaken during April 1990, and a field visitors' day was
held on April 10,1990, to familiarize guests with the operation of the filtration
process. The demonstration took place at the Palmerton Zinc Pile Superfund Site in
Palmerton, PA. The work involved microfiltration of a Superfund waste stream for
the removal of precipitated metals, primarily zinc. The technology includes use of an
automatic pressure filter unit, allowing semi-automatic operation and production of a
relatively dry filter cake. The Tyvek™ filter medium was developed and supplied by
DuPont, The Tyvek™ material, a fine, nonwoven sheet made from high-density
polyethylene, is formed from continuous filaments that are thermally bonded. The
material comes in rolls and provides filter capability to less than one micron. Tyvek™
is extremely resisent to chemical degradation or physical rupture and also allows
clean release of the filter cake. For more information, contact John Martin at
FTS-684-7758 or 513-569-7758.
News from the Centers
m
TCE, DCE
In Situ
Vapor
Extraction
Soil
In Situ Vapor Ixtraction
at Hinson Chemical Site
byAndrd Zownir, Environmental Response Team
and Fred Stroud, Senior OSC, Region IV
•n December 1988, Region IV initiated a buried drum
removal action at the Hinson Chemical Site in Lake Wylie, SC—once the location of
a solvent recovery operation. The trenches were excavated and the drums were
placed in a lined pit. The soil was stockpiled, replaced, and the surface was graded.
The OSC in Region IV requested the Environmental Response Team's (ERT)
Alternative Technology Section to provide treatment options for the soil contami-
nated with 1,1-dichloroethylene, rra/w-l^-dichloroethene, benzene, trichloro-
ethylene, and tetrachloroethylene.
The original soil structure at the site had four layers: an artificial layer of gravel
that contained the highest contaminant levels; a fine sandy loam over a Georgia red
clay layer; and a sand formation which extended into an underlying unconfmed
aquifer. During the removal action, the first three layers were intermixed. The
extent-of-contamination survey showed about half an acre of contaminated soil.
Three soil treatment alternative technologies were proposed and evaluated by the
ERT: soil washing; low temperature thermal desorption; and in situ vapor extraction.
(see ISVE, page 4)
-------
Bioremediatioti
Field Initiative
'SWER and ORD have jointly
instituted a Bioremediation Field
Initiative to provide assistance to the
Regions in conducting field tests and
evaluations of bioremediation site
cleanups planned or in progress over the
next 18 to 24 months.
Sites that should be considered in
this field initiative include CERCLA,
RCRA corrective action facilities, and
UST sites. This initiative is designed to
1) more fully document performance of
full-scale field applications of bioreme-
diation, 2) provide technical assistance
for sites in a feasibility or design stage
to facilitate the conduct of treatability
studies, field pilot studies, etc., and 3)
regularly provide the Regions informa-
tion on treatability studies, design, and
full-scale operations of bioremediation
projects in the Regions.
For more information, contact your
supervisor or call Fran Kremer at FTS-
475-6647 or 202-475-6647.
fSVE (from page 3)
Soil washing and low temperature
thermal desorption were judged to be
unacceptable on the first day of testing
due to the high clay content that would
result in material handling problems.
Additionally, these two technologies
required excavation of the soils. In situ
vapor extraction (IS VE) of the upper
portion of the vadose zone was chosen
for a pilot test at the site.
IS VE employs a well field that
pumps and injects air out of and into the
vadose-zone. For the pilot test, six-inch
diameter bore holes were drilled at
depths up to nine feet One-and-a-quarter
inch perforated pipe was placed in each
of 16 holes. Eight of the 16 holes were
backfilled with crushed stone and native
fill. These were used to pressurize the
ground and enhance the pressure gradi-
ent, forcing vapors to the withdrawal
vents. The exhaust fan used in this study
generated a modest pressure differential
of three inches water. Ten to twenty
kilograms of organic vapors were drawn
through the system in each of the two
days of operation. Six compounds were
monitored during the field exercise.
Calculations indicated that at the
pressure gradient used in the pilot test,
180 to 265 days of operation would be
required to bring vapor levels down to
below detection limits of the field
instruments.
Based on the results of the success-
ful pilot study and the results of an
analysis showing that contamination
extended into the fourth layer as well as
the other three, the OSC directed the
installation of a three-stage IS VE system
with 18 deep and shallow well pairs
along with 16 air injection wells. The
recovered vapor was treated using two
in-series 900 pound vapor phase acti-
vated carbon cells for each system.
The full-scale system started
operations in May, 1990. Each of the
three extraction systems consisted of six
well pairs. In the first three weeks of
operation, the three extraction systems
recovered 60,200, and 500 pounds of the
six target compounds, respectively.
For more information, contact
Andre' Zownir at FTS-340-6740 or
201-321-6740 or Fred Stroud at FTS-
257-3931 or 404-347-3931.
Tech Trends welcomes readers* comments, suggestions for future articles, and contributions.
Address correspondence to: Managing Editor, Teen Trends (OS-110),
U.S. Environmentaf Protection Agency, 401II Street, S.W., Washington, O.C. 20460.
United States
Environmental Protection
Agency ^
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/540/M-90/008
-------
U.S. Environmental
Protection Agency
Office of Solid Waste and
Emergency Responie
Technology limovation Office
EPA&40//M-91/001 No. 4 March 1991
The applied technologies journal for Supeirfund removals and remedial actions and RCRA corrective actions
UV ftadiotion & Reverse Osmosis Combine
to Treat Complex Wastestreams
by Andre Zownir, Environmental Response Team, Edison, New Jersey &
Lou DiGuardia, On-Scene Coordinator, Region II
Metali and
organic*
Reverea
otmosit/
UV radiation
Landfill
teachates
lodem reverse osmosis (RO) technol-
ogy has bem applied to treat complex
wastewatars, chemical spills and landfill
leachates. Although dfectiveibr removing
most heavy metals, RO has not proved
particularly effective for organic compouids.
But recent pilot tests at the PolMon Abate-
ment Services Superrund Site (PAS) in
Osego, New York, added ultraviolet (UVy
ozone/hydrogoi peroxide oxidation pretreat-
ment to thsRO process and successfully
removed many of the organic compounds.
U.S. Army
Joins EPA
The (/.a Army j&fo* fflk
as a contributor to Tech
Trends / ' \ --'/£ ,
T
f. ff
of Superfund sites at 1
facilities the tt& An»jr fsastfc Jrad
Hazardo(is Materiaii Afeaty h ,
devising innovative wtyiiUrtr^at
wastes out site. ,/ . . .
in this issue of T«* Tttote
CptCrafigMytorteUstB about aa
innovadve Low Temperature
Thermal Stripping process to treat
soil contaminated with deaniaf .
soiveots iindfueis. T&e process
expends less energy and is lower in
cost thaE incineration. Boa^tpass
The purpose of the RO/UV study was to
foyiTTmv* if these alternative technologies
were effective enough to avoid the time,
money and manpower to pump, transport
and dispose of kachate* an off-site
treatment facility. Atme PAS site, it was
also necessary to coupkROyUVwith other
on-site tteatment technologies.
All leachate was pretteated prior to
RO/UV treatment Trie first objective of
the pretreatment was to reduce toe iron
content in the leachate by the addition of
sodium hydroxide to separate out the iron in
solid form. Conversely, the second
objective was to increase the solubility of
the mmflining mrtalg fry arJdfrig a^iti sr> that!
(1) the metals did not solidify inside the
2,000 liter reverse osmosis feed tank, thus
pfflmmg rfamage to the membrane: used in
theROprocess; or (2) during the IA^
oxidation process, thus causing scaling on
the quartz shield protecting trie UV lamp.
Reverse osmosis separates low molecular
wejght solvents, like water, from dissolved
solutes (in this case, metals) using a semi-
permeable membrane mat allows permeation
of the solvent while rejecting the solutes. The
driving force for solvent transport across the
RO membrane is pressure. Therefore, to
achieve separation, only pressure is needed—
eliminating the costly phase separations found
in distillation, evaporation and crystallization
technologies.
An Environment Canada mobile RO unit
was used to carry out die reverse osmosis
separation of PAS leachate. Pretreated
leachate was fed into the osmosis system under
high pressure. Semi-permeable membranes
inside the unit separated the leachate into two
streams, permeate and concentrate, and
rejected the metals from the streams. The
concentrate stream went to a holding tank for
processing by ultraviolet oxidation.
(see Reverse Osmosis, page 2)
ATTIC: Biological Treatment
The Alternative Treatment
Technology Information
Center Database contains
23O citations on Biological
Treatment.
See "Out of the ATTIC" on page 3
for one user's experience.
-------
Jtowivo Osmosis
(from page 1)
The permeate scream, now clem water, was
injected into the landfill Overall, RO works
wefl in concentrating heavy metals with
membrane rejections usually above 95%, with
the exception of lead, selenium and zinc. For
example, arsenic concentrations were reduced
from 54 parts par billion (ppb) to 12 ppb and
nickel concentrations from 2580 ppb to non-
detectable levels.
Now for theUV process: Ultraviolet
oxidation is super-oxidation by an oxidizing
chemical, usually ozone or hydrogen
peroxide, in the presence of ultraviolet light
The technology's successful treatment of
various organic-laden waste waters made it a
good candidate for PAS leachate treatment.
Both the RO permeate and concentrate
kachates were fed to the UV system where
the combinaiaa of ultraviolet energy, ozone
and hydrogen peroxide destroy the organic
constituents. TheUV effluent was then sent
for surface discharge or reinjection to the
Iffvffni; this achieved a further leachate
mrtfnmmant TgfJuctiOT1 'n ^ landfill since,
ideally, the effluent stream contains decon-
taminated water. At PAS, the UV unit
provided by Solarchem contained three
upflow reactors in series with separate ozone,
hydrogen peroxide and acid/base addition
ports near the entry to each reactor. The
system controlled pH and ozone and hydrogen
peroxide additions. An ozone generator
provided the unit with the necessary oxidant
UV treatment, by batch runs rather than
continuous runs, was able to lower most
organic contaminant concentrations in
leachate and RO permeate to dischargeable
levels. However, a notable possible probten
was the residual acetone content. Methylene
chloride concentrations were reduced fiom
143 ppb to noQ-desdable levels and nitroben-
zene concentrations from 251 ppb to 4.4 ppb
during 90-minute runs.
From the data at PAS, models were
constructed to assist in the evaluation and
prediction of reverse osmosis performance at
this and other hazardous waste sites. The pilot
tests atPAS also gleaned information on
which of various membranes would be best at
your site.
For more information, call Andy Zownir
of the EPA Environmental Response Team in
Edison, New Jersey, at FTS-3406744 or 908-
321-6744 or call Lou DiGuatdia in Region H
atFTS-321-6712 or 908-321-6711
SITE Subjects
VOCs
Vacuum steam
stripping/Vapor
extraction
Groundwater/
soil
Vacuum Steam
Stripping Combined
with Vaper Extraction
Produces No Air
Emissions
by Gordon Evans, Risk Reduction Engineering Laboratory
jfor the past two years, AWD Technologies, Inc., has been operating their
AquaDetox/SVE system at the San Fernando Valley Superfund Site to remediate
groundwater and soil contaminated with volatile organic compounds (VOCs). The
Site is at a Lockheed Aeronautical Systems facility in Burbank, California. During
September 1990, EPA demonstrated the AquwDetox/SVE system as part of the
Agency's Superfund Innovative Technology Evaluation (SITE) Program.
The process is an automated system that combines a vacuum assisted steam
stripping tower (the " AquaDetox" unit) with a closed loop soil vapor extraction
(SVE) unit The beauty of the system is that it cleans contaminated groundwater
and soil gases within a closed loop, thus eliminating air emissions.
Groundwater contaminated with VOCs enters the top of the AquaDetox unit
stripping tower. Under a moderate vacuum, steam is injected at the bottom. Within
the tower, the organics are stripped from the water, condensed and collected for
recycling. The SVE unit removes contaminated soil gases from the vadose zone
through a network of extraction wells. These soil gases are then exhausted through
two separate granular activated carbon (GAC) beds for hydrocarbon removal. The
cleaned gases are reinjected into the ground.
Among the innovative design features is the periodic regeneration of the GAC
beds for continual reuse.. The AquaDetox/SVE system is designed with three
independent GAC beds in series. Two GAC beds are always on-line for cleansing
soil vapor gases. The remaining bed is taken off-line and steam is injected through it,|
stripping off hydrocarbons. This vapor is then sent back to the AquaDetox unit, r
where the organics are separated, condensed and recycled. In addition, an automated
process control unit continuously monitors and adjusts the operation of the entire I
AquaDetox/SVE system. As a safety feature, the process control unit will shut the
system down when it senses deviations from its normal operating parameters.
At the time of testing, the AquaDetox/SVE system was treating groundwater
contaminated with as much as 2,200 parts per billion (ppb) trichloroethylene (TCE)
and 12,000 ppb tetrachloroethylene (PCE) and soil gas with a total VOC concentra-
tion of 450,000 ppb. Preliminary results suggest that groundwater contaminants are
reduced to virtually non-detectable levels, with soil gas contaminants reduced to
about 350 ppb. Groundwater is being treated at a rate of 1,000 gallons per minute,
while soil gas is treated at a rate of 200 cubic feet per minute. During two weeks of |
EPA's testing, gas and water samples were taken during normal operations. The
system's primary operating parameters were varied: (1) steam flow rate in the
stripping tower, (2) pressure in the stripping tower; (3) groundwater flow rate hi the
stripping tower, and (4) the regeneration frequency of the GAC beds. An Applica-
tion Analysis describing EPA's test results will be available in April, 1991. The
technology may be applicable to your site.
For more information, call Gordon Evans at EPA's Risk Reduction Engineering
at FTS-684-7684 or 513-569-7684.
-------
Out of the ATTIC
The ATTIC at
Oak Ridge
by Cheryl Campbell,
Alternative Treatment
Technology Center
ome of the Department of Energy
(DOE) operations at Oak Ridge,
Tennessee have soil extensively con-
taminated with polychlorinated bi-
phenyls (PCBs). Phil McGinnis, a
Program Manager at the Oak Ridge
National Laboratory (ORNL), was
working on a proposal to demonstrate
bioremediation for site cleanup. Phil
contacted Andrea Richmond, an
Information Specialist at the University
of Tennessee, who consults for ORNL,
about innovative technologies for die
treatment of PCB-contaminated soil by
aerobic and anaerobic microorganisms.
In her own search, bioremediation
technologies for PCB contaminated soil
had been rather scarce; so, Andrea
contacted the ATTIC system operator who
conducted a search for bioremediation of
PCB contaminated soiL Andrea had used
the ATTIC system previously and had
found it to be very useful. This new search
proved fruitful, too. The most useful
information concerned sites at which the
technology had been demonstrated, names
of vendors who had conducted bioremedia-
tion and data on the cost of bioremediation
vs. incineration. The ORNL staff had
narrowed their search to bioremediation
and incineration and they were seeking
specific comparative data on these
technologies. They realized there were
differences between these technologies
which included costs of treatment,
treatment times and demonstrated clean up
levels. Using information found in
ATTIC, the ORNL staff was able to later
estimate that the cost of in situ biological
treatment would be approximately $50 to
$100 per ton. The usual way of treating
PCBs in soil is by excavation and
incineration of the contaminated soil at a
much higher cost Some ATTIC case
study abstracts involved field demonstra-
tions of biological treatment of PCB
contaminated sludges and soils. Mr.
McGinnis used the information, which
contributed to his proposal being funded.
When this search for Oak Ridge was
conducted (November 16,1990) more than
13% of the ATTIC Database contained
information on bioremediation activities.
Since that time, the system has grown to
include more information on bioremedia-
tion, Currently, 20% of the database
contains this type of information.
For help on how to use ATTIC, as
well as information, call the ATTIC
operator at 301-816-9153. Cheryl
Campbell and her staff are ready to assist
you. Or, you can also call Myles E.
Morse, EPA Program Manager for ATTIC,
atFTS475-7161 or 202^75-7161.
Less Energy & Lower Cost with Army's Low
Temperature Thermal Stripping Process
by Cpt. Craig A. Myler, U.S. Army Toxic and Hazardous Materials Agency
VOCs
Low.Tempera-
ture Thermal
Stripping
Soil
waste disposal practices at some
Army facilities have resulted in soil
contaminated with volatile organic
compounds (VOCs) from cleaning
solvents and fuels. Current methods to
treat this soil contamination include
incineration, disposal at a landfill or
hazardous waste disposal facility and in
situ volatilization. The Army has
devised a fourth way, with a system that
expends less energy than an incinerator
and is cheaper to run. The process. Low
Temperature Thermal Stripping, or
LTTS, has been developed and demon-
strated by the U.S. Army Toxic and
Hazardous Materials Agency
(USATHAMA), a Field Operating
Agency fbr the US, Army Corps of Engineers
a the Aberdeen Proving Ground in Maryland.
Pilot and field tests during the past few years
have proved the success of the LTTS. Cur-
renfly, the Navy is using it to clean up the
Crow's Tfl^frng Site in falHrnninL
The Army expects that the LTTS
process will cut the former incineration
costs of $300 per ton of soil by 50%.
LTTS also overcomes limitations encoun-
tered with lower cost in situ volatilization/
vacuum extraction. With in situ volatiliza-
tion, the contaminated soil cannot be very
wet and not all VOC-contaminated soil is
treatable, particularly silty and clayey soils
with low permeabilities.
How does the LTTS process work?
Contaminated soil is fed through an
opening at the top of the system, called the
soil feed hopper. The soil falls into the
main part of the system, or thermal
processor. The thermal processor consists
of two separate but identical units, each
containing four large, hollow screws,
eighteen inches in diameter, twenty feet
long. As the screws turn, they chum the
soil, breaking it up and pushing it from the
feed end of the processor to the discharge
end. In the meantime, hot oil is pumped
through the inside of the screws. The
constant churning of the soil and move-
ment of hot oil up and down the length of
the screws heats the soil and volatilizes
(see LTTS, page 4)
-------
New for the
Bookshelf
Recent EPA publications at*
available from OHD*s Cerrter for
Environmental Research
Information (CERI) in Cincin-
nati. You can order them on ma
OSWER BBS or directly from
CERT* Publications Unit at
FTS-684-7562 or 513469-7562.
You must have th* EPA docu-
ment number or th* exact title
to order a document.
Approaches for Remediation of
Uncontrolled Wood Preserving Sites
An overview of the process of
remediation of uncontrolled wood
preserving sites, emphasizing site
specific factors and multiple technol-
ogy utilization.
Document No. EPA/625/7-90/011
trrs
(from page 3)
the VOCs. Additional heat is provided
by the walls of the processor, called the
trough jacket, which also contains
flowing hot oil. The thermal processor
heats up to a maximum of about 650
degrees Fahrenheit Once the VOCs are
vaporized, they flow through piping into
a burner or other means of treatment,
such as a scrubber or carbon adsorption
system. The VOC-freeairstream then
passes through a discharge stack
monitored for VOCs. In the meantime,
the soil—now virtually VOC-free—falls
into the discharge end of the processor,
where it can be put back into the
excavation area.
What have previous demonstra-
tions concluded? The results of the
pilot and field tests showed the follow-
ing for the particular soils and VOCs
treated: (1) more than 99% of the
VOCs were removed from the soil;
(2) the process equipment available is
capable of treating at least 10 tons of
contaminated soil per hour; and,
(3) there was a 99.99% destruction and
removal efficiency in the afterburner
incineration step. As an example,
trichloroethylene was reduced from
concentrations greater than 111 parts per |
billion (ppb) to 5 ppb; and, toluene was
reduced from 8300 ppb to less than 2 ppb
Federal agencies can send site soil
samples to the U.S. Army Corps of
Engineers Waterways Experiment Statioij
(WES) in Vicksburg, Mississippi, for ]
screening to determine how well the soil I
types can be treated by LTTS. The work|
will be performed on a cost-reimbursable
basis. The results will be published in a
report discussing the results of the soil
samples that were used. The WES target||
date for having the treatability study
capability is May 1991. However, some !
laboratories have the capability to perforrf
.lifts service now (for both Federal
"agencies and non-Federal parties).
Federal agencies interested in
sending soil samples for pre-screening b j
WES should contact Daniel Averett,
WES, at 601-634-3959. For more
information on the technical aspects of
the LTTS, or for laboratories with currer]
capability to pre-screen soil samples,
contact CpL Craig Myler, USATHAMAj
at 301-671-2054.
Tech Trends welcomes readers' comments, suggestions for future arucies and contributions.
Address correspondence to: Managing Editor, Tech Trends {OS-110)j
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