&EFA
U.S. Environment!!
Protection Agency
Office of Solid Waste and
Emergency Response
Technology Innovation Office
EPA/540//M-91/001 No. 4 March 1991
The applied technologies journal for Superfund removals and remedial actions and RCRA corrective actions
UV Radiation & Reverse Osmosis Combine
to Treat Complex Wastestreams
by Andre Zownir, Environmental Response Team, Edison, New Jersey &
Lou DiGuardia, On-Scene Coordinator, Region II
Metal* and
organic*
Reverse
osmosis/
UV radiation
Landfill
leachates
I odem reverse osmosis (RO) technol-
ogy has been applied to treat complex
wastewaters, chemical spills and landfill
leachates. Although effective for removing
most heavy metals, RO has not proved
particularly effective for organic compounds.
But recent pilot tests at the Pollution Abate-
ment Services Superfund Site (PAS) in
Osego, New York, added ultraviolet (UVy
ozone/hydrogen peroxide oxidation pretreat-
ment to the RO process and successfully
removed many of the organic compounds.
U.S. Army
Joins EM
The U.S. Army Joins EPA
as a contributor to
Trends
•o meet the challenge of cleanup
of Superfong sifts at federal
facilities, the U.S. ArroyTwdc and
Hazardous Materials Agency is
devising innovative ways to treat
wastes on site.
In this issue of Tecb Trends
Opt. Craig Myler tells us about an
innovative Low Temperature
Thermal Stripping process to treat
soil contaminated with cleaning
solvents aad fuels. The process
expends less energy and is lower in
cost than incineration. Don't pass
up Cpt Myler's article on page 3.
The purpose of the RO/UV study was to
determine if these alternative technologies
were effective enough to avoid the time,
money and manpower to pump, transport
and dispose of leachate at an off-site
treatment facility. At the PAS site, it was
also necessary to couple RO/UV with other
on-site treatment technologies.
All leachate was pretreated prior to
RO/UV treatment. The first objective of
the pretreatment was to reduce the 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 remaining metals by adding acid so that:
(1) the metals did not solidify inside the
2,000 liter reverse-osmosis feed tank, thus
causing damage to the membrane used in
theROprocess; or (2) during the UV
oxidation process, thus causing scaling on
the quartz shield protecting the UV lamp.
Reverse osmosis separates tow molecular
weight solvents, like water, from dissolved
solutes (in this case, metals) using a semi-
permeable membrane that allows permeation
of the solvent while rejecting the solutes. Tbe
diiving force for solvent transport across the;
ROmembrane 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 the reverse osmosis
separation of PAS leachate. Pretreated
leachate was fed into the osmosis system under
high pressure. Semi-permeabte 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
Tho Alternative Treatment
Techno lo<|y Information
Center Databaso contains
23O citations on Biological
Treatment.
See "Out of the ATTIC" on page 3
for one user's experience.
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Osmosis
(from page 1)
The penneate stream, now clean water, was
injected into tbe landfill. Overall, RO works
weH in concentrating heavy metals with
membrane rejections usually above 95%, with
the exception ofleaci,sdenium and zinc. For
example, arsenic concentrations were reduced
from54partsperbillk)o(ppb)tol2ppband
nkkel concentrations from 2580 ppb to non-
detectable levels,
Now for theUV process: Ultraviolet
oxk&ion is super-oxidation by an oxidizing
chemical, usually ozone or hydrogen
peroxide, M 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 penneate and concentrate
kachates were fed to the UV system where
the combination of ultraviolet energy, ozone
and hydrogen peroxide destroy the organic
constituents. TheUV effluent was then sent
for surface discharge or reinjection to the
landfill; tMs achieved a further leachate
contaminant reduction in the 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 crmrentratfons in
leachate and RO permeate to dischargeable
levels. However, anotaMe possible problem
was the residual acetone content Methylene
chloride concentrations were reduced from
143 ppb to non-detectable 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 she.
For more information, call AndyZownir
of the EPA Environmental Response Team in
Edison, New Jersey, at FrS-340-6744 or 908-
321-6744 or call Lou DiGuardia in Region H
at FTS-321-6712 or 908-321-6712.
SITE Subjects
VOCs
Vacuum steam
stripping/vapor
extraction
Groundwater/
soil
Vacuum Steam
Stripping Combined
with Vapor Extraction
Produces No Air
Emissions
by Gordon Evans, Risk Reduction Engineering Laboratory
_Toi 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 (VO6s). The
Site is at a Lockheed Aeronautical Systems facility in Burbank, California.- During
September 1990, EPA demonstrated the AquaDetox/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
where the organics are separated, condensed and recycled. In addition, an automated
process control unit continuously monitors and adjusts the operation of the entire
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 in 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.
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Out of the ATTIC
The ATTIC at
Oak Ridge
by Cheryl Campbell,
Alternative Treatment
Technology Center
«*lome 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 the
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.
McGimiis used the information, which
contributed to his proposal being funded.
When this search for Oak Ridge was
conducted (November 16,1990) more main
13% of the ATTIC Database contained
information on bioremediation activities.
Since that time, the system has grown to
include more information on biqremedia-
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 MylesE.
Mcise, EPA Program Manager for ATTIC,
atFTS-475-7161 or 202-475-7161.
-
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
ast 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 for the VS. Army Corps of Engineers
at the Aberdeen Proving Ground in Maryland.
Pilot and field tests during the past few years
have proved the success of the LTTS. Cur-
rently, the Navy is using it to clean up the
Crow's Tflnrjing Site in California.
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 churn 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
i
(see LTTS, page 4) j
-------
New for the
Bookshelf
Recent EPA publication* «r»
tvailabi* from 08B** Center tar
Environmental Roewrch
Information (CER1) in Cincin-
nati. You can order them on the
OSWER BBS or directly from
CERI't Publication* Unit at
FTS-684-7562 Or 513-569-7592.
You must have the EPA docu-
ment number or the exact tRie
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
LTTS
(from page 3)
theVOCs. 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-fteeairstream 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 sou
samples to the U.S. Army Corps of
Engineers Waterways Experiment Station
(WES) in Vicksburg, Mississippi, for pre-
screening to determine how well the soil
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 perform
this service now (for both Federal
agencies and non-Federal parties).
Federal agencies interested in
sending soil samples for pre-screening by
WES should contact Daniel Averett,
WES, at 601-634-3959. For more
information on the technical aspects of
the LTTS, or for laboratories with current
capability to pre-screen soil samples,
contact Cpt. Craig Myler, USATHAMA,
at 301-671-2054.
Tech Trend* welcomes readers' comments, suggestions for future articles and contributions.
Address correspondence to: Managing Editor, Tech Trends (OS-110),
U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, DC 20460.
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
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PERMIT No. G-35
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Penalty for Private Use $300
EPA/540/M-91/001
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