EPA/542/N-93/001 No. 11 January 1993
U.S. Environmental
Protection Agency
Office of Solid Waste
and Emergency
Response
Technology
Innovation Office
The applied technologies journal for Superfund removals and remedial actions and RCRA corrective actions
Extraction Process Separates Organks
from Sludges, Soils and Sediments
by Mark Meckes, Risk Reduction Engineering Laboratory
Organics
Solvent
extraction
Soils, sediments
and sludges
• he Basic Extractive Sludge Treatment
(BJ3.S.T,®) process is a solvent extraction
system that uses triethylamine to separate
organic contaminants from sludges, soils
and sediments. The B.E.S.T.® process
was pilot demonstrated under the EPA's
Superfund Innovative Technology Evalu-
ation (SITE) program in cooperation with
the Great Lakes National Program Office
and the U.S. Army Corps of Engineers.
The demonstration treated river bottom
sediment from the Grand Calumet River
in Gary, Indiana, which was contaminat-
ed with oil and grease, polychlorinated
biphenyls (PCBs) and polynuclear aro-
matic hydrocarbons (PAHs).
The key to the success of triethyl-
amine extraction is the property of
inverse miscibility. At temperatures below
60 degrees Fahrenheit, triethylamine is
miscible with water; above 60 degrees
Fahrenheit, triethylamine and water are
only slightly miscible. A triethylamine
solvent chilled below 60 degrees
Fahrenheit mixes well with water, thus
attracting water and contaminants from
solids,, resulting in a non-homogenous
mixture of moisture-free solids and a
solution of solvated oil, water and solvent.
This is referred to as "cold extraction."
Later, during the "hot extraction," the
organic contaminants that remain in the
dewatered solids are removed by warm
triethylamine, which is heated to temp-
eratures ranging from 70 to 160 degrees
Fahrenheit and above. Triethylamine moves
conlaminants from moisture-free solids more
effectively at these higher temperatures.
The B.E.S.T.® process operates as
follows. Contaminated material is screened
to less than 1/2 inch diameter (1/8 inch for
this demonstration) and added to a
refrigerated premix tank with a
predetermined volume of 50% sodium
hydroxide. After the tank is sealed and
purged with nitrogen, chilled triethylamine
solvent is added. The chilled mixture is
agitated and then allowed to settle, creating
the non-homogenous mixture of moisture-
free solids and the solution of solvated oil,
water and solvent The solution is decanted
from the solids and centrifuged. The
solvent and water are removed from the
(see B*E*S*TB page 2)
Sediment Cleanup
Featured
* nnovative technologies that
remediate sediments are the
subject of two articles in this
issue of Tech Trends, The
B.E.S.T® process on this page
addresses river bottom
sediment in the Grand Calumet
River in Gary, Indiana. The
update on the ATP process on
page 4 gives results on
remediation of PCBs in
sediment in Waukegan Harbor
in Illinois.
ATTIC* Reports on Remediating
Explosives-Contaminated Soil
Bioaugmentation
Physical Treatments
7(4%)
Incineration
32(18%)
Bioremediation
30 (17%)
Composting
54 (3,0%)
Thermal Treatments
48 (27%)
*Alternative Treatment Technologies Information Center
Recycled/Recyclable
Printed with Soy/Canola Ink on paper that
contains at least 50% post-consumer recycled fiber
-------
SITE Subjects
Organics Desorbed
from Soil with Low
Temperature Thermal
Treatment
•^flfite.
VOCs/SVOCs
Thermal
desorption
Soil
by Paul R. dePercin, Risk Reduction Engineering Laboratory
• he Roy F. Weston, Inc., low tempera-
ture thermal treatment ^ysteTri (IT3®) "
thermally desorbs organic compounds
from contaminated soil without treating
the soil to combustion temperatures. The
LT3® can process a wide variety of soils
with differing moisture and contaminant
concentrations. Bench, pilot or full scale
systems have been used to treat soil con-
taminated with coal tar, drill cuttings
(oil-based mud), petroleum hydrocar-
bons, halogenated and nonhalogenated
volatile organic compounds (VOCs) and
semivolatile organic compounds (SVOCs),
including polynuclear aromatic hydrocar-
bons. The LT3® was demonstrated under
the Superfund Innovative Technology
Evaluation Program (SITE) at the Ander-
son Development Company (ADC) site
in Adrian, Michigan, where the soil was
contaminated with VOCs and SVOCs,
including 4,4-methylene-bis(2-chloro-
aniline) (MBOCA).
The system is divided into three
main areas of treatment: soil treatment,
emissions control and water treatment.
The thermal processor for soil treatment
consists of two jacketed troughs, one
above the other. Each trough houses
four intermeshed screw conveyors. A
front-end loader transports feed soil (or
sludge) to a weigh scale and deposits the
material onto a conveyor that discharges
into a surge feed hopper located above
the thermal processor. The surge hopper
is equipped with level sensors and pro-
vides a seal over the thermal processor to
minimize air infiltration and contaminant
loss. Heat transfer fluid (typically hot
oil) from the burner circulates through
the hollow screws and trough jackets as
" the soirmoves^cro^mFTipper^oughT*
drops to the second trough and exits the
processor at the same end that it entered.
Thus, each screw conveyor mixes, con-
veys and heats the contaminated soil dur-
ing treatment. Soil is discharged from the
thermal processor into a conditioner
where it is sprayed with water to reduce
the temperature and to minimize fugitive
dust emissions. An inclined belt conveys
the treated soil to a truck or pile.
The hot oil, or heat transfer fluid,
used above is heated in the burner to an
operating temperature of 400 to 850 F
(about 100 F higher than desired soil
temperature). Combustion gases released
from the burner are used as sweep gas in
the thermal processor, where a fan draws
the sweep gases and desorbed organics
from the thermal processor through a
fabric filter baghouse. Exhaust gas from
the filter is drawn into an air cooled
-condensorno remove most'of the water
vapor and organics and then through a
second, refrigerated condenser to further
lower the temperature and reduce the
moisture and organic content of the off-
gases. Electric resistance heaters then
increase the off-gas temperature to
approximately 70 F to optimize the per-
formance of the vapor-phase activated
carbon column which removes any
remaining organics. The condensate
stream is typically treated in a three-
phase oil-water separator to remove
light and heavy organics from the water,
which is then treated in a carbon
(see LT page 3)
(from page 1)
solvent/water/oil mixture by evaporation
and condensation of the solvent and water.
Solids with high moisture content may
require more than one cold extraction. For
example, for this demonstration, a
sediment containing 41% moisture
required two cold extractions.
Once a sufficient volume of mois-
ture-free solids is accumulated, it is trans-
ferred to a steam jacketed extractor/dryer
where warm triethylamine is added to the
solids.—T-he-mixtuse-is--heated, -agitated,—
settled and decanted to separate any of
the organics not removed during the ini-
tial cold extraction. The solids remaining
in the extractor/dryer contain triethyl-
amine following decanting. A small
amount of steam is injected to volatilize
this remaining triethylamine. The hot ex-
traction process can be repeated, when
necessary, to further remove contaminants.
The products from the process are:
(1) solids, (2) water and (3) concentrated oil
containing the organic contaminants. The
recovered oil fraction can be dechlorinated
or incinerated to destroy the organics. The
triethylamine is recovered and reused in
further extractions.
Two sediment samples were treated
for this SITE demonstration. Sediment A
contained 41% moisture, 6,900 milligrams
oil and grease per kilogram of sediment
(mg/kg), 12 mg/kg PCBs and 550 mg/kg
PAHs. The process removed greater than
^98%-of«the-oil and grease, 99% o£4he
PCBs and greater than 96% of the PAHs.
Sediment B contained 64% moisture,
127,000 mg/kg oil and grease, 430 mg/kg
PCBs and 73,000 mg/kg PAHs. The pro-
cess removed greater than 98% of the oil
and grease and greater than 99% of the
PCBs and PAHs. The residual solvent in
the process' products of solids, water and
oil (Sediment B) was 103 mg/kg, less than
1 nig per liter and 730 kg, respectively.
For more information, call Mark
Meckes at EPA's Risk Reduction
Engineering Laboratory at 513-569-7348.
A Technical Evaluation Report and an
Applications Analysis Report describing
the complete demonstration will be
available in the summer of 1993.
-------
Evaporation/Oxidation
System Treats A Variety
of Wastewater
Contaminants ^
by Randy Parker, Risk Reduction Engineering Laboratory
Organics, metals,
pesticides,
radiowastes
Evaporation
and oxidation
Waste water,
ground water
f he PO*WW*ER™ Process treats a
variety of wastewaters by reducing the
volume of aqueous waste and catalyti-
cally oxidizing volatile contaminants.
The technology, developed in 1988 by
Chemical Waste Management, Inc., was
evaluated under -the .Superfund
Innovative Technology Evaluation
(SITE) program at the Lake Charles
Treatment Center, Lake Charles,
Louisiana. PO*WW*ER™ can treat
landfill leachate, contaminated ground
water, process wastewater and low-level
radioactive mixed waste. The system
can also treat wastewater containing
volatile and semivolatile organic com-
pounds (VOCs and SVOCs), pesticides,
herbicides, solvents, heavy metals,
cyanide, ammonia, nitrate, chloride,
sulfide, plutonium, americium, uranium,
technetium, thorium and radium.
The major components of the
PO*WW*ER™ are: (1) an evaporator
that reduces influent wastewater volume,
(2) a catalytic oxidizer that oxidizes the
volatile contaminants in the vapor
stream from the evaporator, (3) a scrub-
ber that removes acid gases produced
during oxidation and (4) a condenser that
condenses the vapor stream leaving the
scrubber. The waste feed enters the
evaporator from a stainless steel feed
tank where the waste had been prepared
by additives to control foaming and pH.
The evaporator has three main compo-
nents: the heat exchanger, the vapor
body and an entrainment separator. The
waste is first heated in a heat exchanger
before it passes into the vapor body
where the waste reaches a boiling point
and separates into a vapor phase and a
brine phase. Some of the brine is col-
lected by gravity into a waste brine drum
while the remaining brine is recirculated
in the vapor body. The vapor exits to an
entrainment separator where it passes
through a mesh pad mat entrains droplets
and particles.
The vapor that passed through the
entrainment mesh enters the catalytic
oxidizer where it is further heated and then
passed through a catalyst bed which oxidizes
the VOCs and inorganic contaminants. After
oxidation, the vapor stream exits the oxidizer
... into the scrubber where it, passes through a
packed bed containing a caustic solution that
neutralizes the acid gases. The vapor is
cooled and condensed. The product conden-
sate can either be reused as boiler or cooling
tower water or discharged to surface water, if
appropriate (i.e., if the condensate meets
National Pollution Elimination Discharge
System requirements). The noncondensible
gases can be vented to the atmosphere if
they meet permit requirements as they did
at Lake Charles.
No VOCs, SVOCs, ammonia or cyanide
were detected in the condensate. The orig-
inal feed waste had contained concentrations
of VOCs ranging from
270 to 110,000 micro-
grams per liter (|J.g/L),
SVOCs ranging from
320 to 29,000 |o.g/L;
ammonia ranging from
140 to 160 milligrams
per liter (mg/L); and
cyanide ranging from
24 to 35 mg/L. The
PO*WW*ER™ system
effectively reduced the
volume of aqueous
wastes and concentrated
the contaminants in the
waste feed to be treated
For more informa-
tion, call Randy Parker
atEPA's Risk Reduc-
tion Engineering Labo-
ratory at 513-569-7271.
Also call Randy to get
on the mailing list for
the Applications Analy-
sis Report and Technol-
ogy Evaluation Report on
the SITE demonstration.
(from page 2)
adsorption system to remove residual
organic contaminants.
At the ADC SITE demonstration,
the LT3® removed VOCs to below
method detection limits (less than 0.060
milligrams per kilogram [mg/kg]) for
most compounds, from initial concen-
trations of about 50 mg/kg. MBOCA
removal efficiency was greater than
88%; concentrations in the treated
sludge ranged from 3.0 to 9.6 mg/kg
gas opposed to 43.6 to 860 mg/kg in
untreated sludge. All SVOCs, with two
exceptions, decreased in concentration
in the sludge.
Low levels of dioxins and furans
were formed in the LT3® system. The
majority of these were recovered or
treated by the gas and liquid residuals
treatment system. The sampling results
will be discussed in the Technical Eval-
uation Report and the Application
Analysis Report which will be available
in early 1993. For more information,
contact Paul dePercin at EPA's Risk
Reduction Engineering Laboratory at
513-569-7797.
Conference
Alert
LookforEPAatAIChE
Conference
March 30, 1993
EPA will present sessions on hazardous waste remediation
technologies at the American Institute of Chemical Engi-
neers' (AIChE) conference in Houston, Texas, on March 30,
1993. The AIChE conference will be held in conjunction
with Petrochemical Expo '93.
One of the EPA sessions (Session # 99) will address technol-
ogy trends, including biological treatment processes for
polyaromatic hydrocarbons and results from recently com-
pleted Superfund Innovative Technology Evaluation (SITE)
projects utilizing soil washing and thermal technologies.
Another session (# 100) will include interactive demonstra-
tions of computer databases that contain extensive informa-
tion on treatment technologies. For further information, call
Denise DeLuca at 212-705-7344.
-------
Update
Anaerobic Thermal Processor Gompletes Second
PCB
• n the December 1991 issue of Tech
Trends we told you about the anaerobic
thermal processor (ATP) that had
removed polychlorinated biphenyls
(PCBs) from contaminated soils during
cleanup activities at the Wide Beach
Development site in Brant, New York.
The ATP, which was evaluated at,W.ide._
Beach under EPA's Superfund Inno-
vative Technology Evaluation (SITE)
program, has been the subject of a
second successful SITE evaluation
conducted on sediments and soils at the
Outboard Marine Corporation (OMC)
site in Waukegan, Illinois. The ATP,
which involves a physical separation
process that thermally desorbs organics
such as PCBs from soil, sediments and
sludge, is also designed to treat wastes
with a nominal hydrocarbon concentration
of 10%.
At both Wide Beach and OMC, the
ATP unit removed PCBs in the
contaminated soil to levels at and below the
desired cleanup concentration levels of 2
parts per million (ppm). At Wide Beach,
.-PCB conGenttations^yere ^reducedfrom^an,
average concentration of 28.2 ppm in the
contaminated -feed soil to an average
concentration of 0.043 ppm in the treated
soil. At the OMC site, PCB soil con-
centrations were reduced from an average of
9,761 ppm to 2 ppm. No volatile/
semivolatile organic (VOC/SVOC) degra-
dation products or leachable VOC/SVOCs
were detected in the treated soil at Wide
Beach; at OMC, leachable VOCs and
SVOCs and metals were below Resource
Conservation and Recovery Act toxicity
characteristic standards. At OMC approx-
imately 0.12 mg of PCBs per kilogram of
PCBs fed to the ATP were discharged
from the system's stack.
The ATP system was developed by
UMATAC Industrial Processes under
^b^sponsorship^Qf the. Alberta Oil
Sands Technology and Research
Authority (AOSTRA) and is licensed by
SoilTech ATP Systems, Inc., a United
States corporation.
For more information, call Paul
dePercin at the EPA's Risk Reduction
Engineering Laboratory at 513-569-7797.
An Applications Analysis Report and a
Technology Evaluation Report describing
the SoilTech ATP SITE demonstrations
will be available in the Spring of 1993.
To order additional copies of this or previous issues of Tech Trends, or to be included on the permanent mailing
list, send a fax request to the National Center for Environmental Publications and Information (NCEPI) at
513-891-6685, or send a mail request to NCEPI, 11029 Kenwood Road, Building 5, Cincinnati OH 45242.
Please refer to the document number on the cover of the issue if available.
Tech Trends welcomes readers' comments and contributions. Address correspondence to:
Managing Editor, Tech Trends (OS-110W), U.S. Environmental Protection Agency,
401 M Street, S.W., Washington, DC 20460.
United States
Environmental Protection Agency
National Center for Environmental Publications and Information
Cincinnati, OH 45242
Official Business
Penalty for Private Use $300
EPA/542/N-93/001
BULK RATE
Postage and Fees Paid
EPA
G-35
------- |