United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S2-88/051 Nov. 1988
&EPA Project Summary
Evaluation of the B.E.S.TJM
Solvent Extraction Sludge
Treatment Technology
Twenty-Four Hour Test
Gerard W. Sudell
A twenty-four hour sampling
and analytical effort was conducted
on Resources Conservation Co.'s
Solvent Extraction Sludge Treatment
Technology prototype full-scale
commercial facility while operating at
the General Refining Superfund site
in Garden City, Georgia. The site was
contaminated with oily residues
resulting from waste oil rerefining
and reclamation operations. The
B.E.S.T.™* sludge treatment tech-
nology was tested to determine its
suitability for application as a trans-
portable on-site treatment technol-
ogy for spill and waste site cleanups,
with special potential for oily
hazardous waste materials. The
process separates oily sludges into
their component oil, solids, and
water fractions, and conditions them
for disposal or for further treatment
The test data confirm the
system's capability to separate the
sludges as predicted, often in
efficiencies of over 98%. Comparison
of laboratory simulation data to field
data indicates that laboratory-scale
simulations can be useful in pre-
dicting system performance.
This Project Summary was
developed by EPA's Risk Reduction
Engineering Laboratory, Cincinnati,
OH, to announce key findings of the
"Mention of trade names or commercial products
does not constitute endorsement or recom-
mendation for use
data evaluation, which are
documented in the report.
Introduction
B.E.S.T.™ solvent extraction sludge
treatment technology data were
generated during a twenty-four hour
performance test conducted at the
General Refining site in Garden City,
Georgia. The test was conducted by the
Resources Conservation Co. (RCC) with
the assistance of EPA's Region X
Environmental Services Division in
cooperation with EPA's Region IV
Emergency Response and Control
Branch.
The General Refining site, located
near Savannah, Georgia, was operated as
a waste oil reclamation and rerefining
facility from the early 1950s until 1975.
Sulfuric acid used to treat the waste oil
produced an acidic oily sludge, while
process filtration produced an oily filter
cake by-product. The sludge was
disposed of in four unlined lagoons, and
the filter cake was buried and stockpiled
on-site. An additional unlined lagoon
that had been used as an oil-water
separator was backfilled with filter cake
and sludge, and waste oil was stored in
bulk tanks on-site.
To remedy the situation, site cleanup
actions were initiated in the summer of
1986 to stabilize the site, secure the
facility, and explore disposal alternatives.
In evaluating disposal alternatives,
consideration was given to on-site and
off-site incineration, landfilling, and on-
site solvent extraction. The B E.S.T.™
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solvent extraction process was chosen as
the most suitable and cost-effective
option.
In mid-1986 RCC mobilized and
installed its prototype full-scale
commercial solvent extraction sludge
treatment system at the General Refining
site. After shakedown and modification of
the prototype 100 ton/day system,
approximately 3,700 tons of oily sludges
from the petroleum rerefining operations
were treated. The B.E.S.T.™ system
operation concluded in March 1987.
The initial sampling and analytical
activity conducted during the removal
operation was directed at verifying the
composition of the product streams. RCC
previously had evaluated petroleum
industry sludges at the laboratory-scale
level. These efforts resulted in data that
tracked the isolation of contaminants into
the oil, water, and solids fractions, and
also determined EP toxicity and TCLP
results for the solids residues. The
General Refining operation provided the
opportunity to compare a prototype full-
scale commercial facility's data with the
laboratory-scale data for treatment of
hazardous waste sludges.
RCC, in cooperation with EPA's
Region X, then developed and imple-
mented a twenty-four hour sampling
and analysis project to evaluate the
system's performance and efficiency
both in the separation of the feed com-
ponents and in the isolation of con-
taminants into specific product streams.
The Technology Evaluation report is
divided into six sections: introduction;
summary and conclusion outlining the
performance of the technology during the
sampling effort; brief description of the
General Refining site; description of the
technology; discussion of the system
operation and data collected during the
test period; and quality assurance/quality
control.
The General Refining site was used
from the early 1950s to 1975 as a waste
oil reclamation and rerefining facility. The
site is located off Route 80, Chatham
County, in Garden City, Georgia, west of
Savannah. The total volume of waste
generated was estimated to be in excess
of 10,000 tons. Analysis of the waste oil,
sludge, and filter cake performed during
an early material characterization phase
of the RCC project revealed the
presence of petroleum compounds,
heavy metals including lead and copper,
PCBs, and low-pH sludges and water.
Composition of the sludges and soils
at the site varied widely from point to
point laterally and vertically within the
lagoons. Nominal composition in weight
percent was approximately 10% oil, 70%
water, and 20% solids, but during actual
operation oil ranged from 0-40%, water
from 60-100%, and solids from 2-
30%. During the twenty-four hour test
period the feed was fairly consistent at
27% oil, 66% water, and 7% solids.
Primary contaminants in the feed were
PCBs ranging from 1 to 13 mg/kg, and
lead ranging from 2200 to 7400 ppm.
The sludge at the site exhibited
some unusual physical properties. The
untreated sludge formed an emulsion
that was hydrophobic and could not be
mixed with water. The sludge was
determined to be rheopectic, since
mixing acted to increase its viscosity,
changing it from a paste-like state to a
semi-solid. Viscosity readings on
several samples ranged from 490,000 to
530,000 centipoise Brookfield.
The site remediation involved
neutralizing the sludge from the lagoons
and then processing it through the
B.E.S.T.™ solvent extraction system
where it was separated into its oil, water,
and solids product fractions. Some of the
product oil was transported off-site with
the remainder stored on-site for
treatment by other methods; the product
water was first treated on-site and then
transported to a nearby industrial
wastewater treatment system; and the
product solids were stored on-site.
Procedure
The RCC.'s prototype full-scale
commercial facility has a nominal
capacity of 100 ton/day wet throughput.
The system is modular, is capable of
being transported to contaminated sites
for operation and cleanup, and offers the
capability to include all required on-site
utilities except for electricity and potable
water.
The B.E.S.T. M sludge treatment
system processes difficult-to-treat
emulsified oily sludges by breaking the
emulsion and physically separating the
sludge into three separate fractions.
These fractions-oil, water, and sol-
ids-then can be handled separately.
As the fraction separations take place,
certain contaminants can be removed
from the original sludge and con-
centrated into a specific phase; for
example PCBs concentrate in the
product oil fraction, and metals in the
product solids fraction. This separation
permits a determination of the most
appropriate methods for disposal and the
suitability for recycling or reuse of the
separated fractions.
The process uses one or more of a
family of aliphatic amine solvents to
break oil/water emulsions and rele
bonded water from the sludge.
solvent used at the General Refining
triethylamine (TEA), becomes comple
miscible with water when cooled b<
20°C, but upon heating becor
immiscible. The process mixes rel
erated TEA solvent with the oily slud
releasing solids from the oil/w<
emulsion. The solids are removed
centrifugation and dried. Solvent
separated from the oil and water fracti
using distillation techniques.
The oil product fraction is chemic
unaltered by the process and has
same characteristics as the feed mate
The objective is to recover and reuse
fraction as a fuel or process feedstc
The water product fraction, whi
volume increases by approximately 2
due to steam condensation within
system, is able to be treated <
discharged. The solids residual is pow
dry and contains only traces of the oil.
Sludge feed limitations are prime
large particle size and reactivity with
process solvent. Process performai
can be influenced by feed characteris
such as the presence of detergents ;
emulsifiers, or of low-pH mater
Detergents can result in degraded s
aration efficiency resulting in increa;
concentrations of oil and grease in
product water, and increased wa
content in the product oil. Emulsifi
can affect organics separation from
water fraction. Low pH material must
neutralized to prevent reactions with ;
loss of the solvent.
During operations at the si
preprocessing treatment consisted
screening the filter cake and bacl
material through a 1/4-inch hammern
which crushed the material to the s
desired for processing. Sludge from
ponds, often in excess of 1,000,C
centipoises, was pumped into a vibrat
screen and placed into storage tanks
await processing. Since the sludge v
highly acidic, it was neutralized w
sodium hydroxide. A feedrate
approximately 40 ton/day was maintair
during the test period. The oil prod
was discharged into an oil polisher
further separate water from the oil, I
solids were discharged from the sol
dryer through an exit chute into stora
containers, and the water was furtt
processed in an on-site treatrm
system.
Posttreatment requirements for 1
separated fractions vary betwe
applications. Some product oil, water,
solids upgrading may be need
depending on the intended disposition
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these materials. For example, if the
solids are to be landfilled, some further
treatment such as fixation may be
required. PCBs can be isolated in the oil
fraction and either can be chemically or
thermally destroyed by subsequent
treatment or used as fuel if the PCS
contamination is within regulatory limits.
The product water is treated in an
on-site water treatment plant prior to
discharge. The water treatment plant is a
modular facility using two-stage
clarification. The first stage consists of
acidifying the water and adding a
flocculent and an oil/water emulsion
breaker. Then lime is added to raise the
pH and aid in precipitating lead (Pb), and
a contact clarifier is used to settle out
sludge materials.
The B.E.S.T.™ sludge treatment
process is operated with the use of an
automatic control system that monitors
process conditions and makes process
adjustments as required. A process
operator monitors the control system and
makes additional adjustments. Samples
of the feed and product streams are
collected periodically and analyzed to
ensure proper system operation.
Since the General Refining site was
an inactive site, RCC was required to
supply all necessary utilities other than
electricity and service water. RCC
provided a mobile oil-fired boiler for
steam generation, a cooling tower for
cooling water, a cryogenic nitrogen (Na)
storage system, a water product
treatment facility, and instrumentation air
for process equipment operation.
Results and Discussion
The B.E.S.T.™ solvent extraction
sludge treatment 100 ton/day prototype
commercial facility operation at the
General Refining site demonstrated the
system's capability to separate oily
feedstock into its oil, water, and solids
product fractions and to concentrate
certain contaminants into a specific
product fraction. Separation efficiencies,
defined as the amount of desired product
less the amount of all undesired products
times 100, often exceeded 98%. The
solids product stream was shown to
contain less than 0.5% moisture, with
very little oil contamination; the oil
product contained only 0.88% water; and
the water product contained 0.0033% oil
and less than .81 % total solids.
After separation, the streams were
analyzed for contaminant concentrations
to ascertain that specific key con-
taminants had concentrated preferentially
into a particular product fraction. The
contaminants of interest were PCBs,
lead, metals, volatiles, semivolatiles, and
chlorinated dioxins and furans. In general
the PCBs, volatiles, and semivolatiles
concentrated in the oil fraction, with little
contamination found m the solids and
water product fractions. Metals mostly
concentrated in the solids fraction, but
lead concentrated into both the solid and
oil fractions, suggesting that lead m the
sludge feed was bound inorganically as
well as organically Chlorinated dioxins
and furans were below detection limits in
the raw sludge feed. On-site water
treatment reduced most levels of
contaminants in the discharged treated
product water, maintaining about the
same semivolatiles concentrations,
slightly reduced volatiles, and signifi-
cantly reduced metals concentrations.
Conclusions and
Recommendations
The General Refining operation was
the first full-scale test of the B.E.S.T.™
sludge treatment technology. The data
indicate the system's capability to
separate oily sludges as predicted, in
efficiencies of over 98%, and to produce
disposable product streams. In addition,
comparisons of laboratory simulation
data to field data indicate that
laboratory-scale simulations can be
useful in predicting system performance.
Although the current data confirm the
system's capability to perform as
designed, further testing over an
extended period of time should be
undertaken when the system is operating
at another site. Testing over a longer
period of time can aid in the affirmation
of the effectiveness of the process and in
the development of operating and cost
data.
The full report was submitted in
partial fulfillment of Contract No. 68-
03-3255 by Enviresponse, Inc., under
sponsorship of the U.S. Environmental
Protection Agency.
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Gerard W. Sudell is with Enviresponse, Inc., Edison, NJ 08837
Mary K. St/nson is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of the B.E.S.T.™ Solvent Extraction
Sludge Treatment Technology Twenty-Four Hour Test," (Order No. PB
88-245 9071 AS; Cost: $19.95, subject to change) will be available only
from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Edison, NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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IL 60604
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