United States
Environmental Protection .
Agency
Municipal Environmental Research XN
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-83-100 Dec. 1983
&ERA Project Summary
Mobile System for Extracting
Spilled Hazardous Materials
from Excavated Soils
Robert Scholz and Joseph Mifanowski
A technique was evaluated for the
scrubbing or cleansing of excavated
soils contaminated by spilled or
released hazardous substances.
Laboratory tests were conducted with
three separate pollutants (phenol,
arsenic trioxide, and polychlorinated
biphenyls [PCB's]) and two soils of sig-
nificantly different character
(sand/gravel/silt/clay and organic
loam).
The tests show that scrubbing of
excavated soil on site is an efficient
approach for freeing soils of certain
contaminants but that the effectiveness
depends on the washing fluid (water +
additives) and on the soil composition
and particle-size distribution. Based on
the test results, a full-scale, field-use,
prototype system was designed,
engineered, fabricated, assembled, and
briefly tested under conditions where
large (>2.5 cm) objects were removed
by a bar screen. The unit is now ready
for field demonstrations.
The system includes two major soil
scrubbing components: a water-knife
stripping and soaking unit of novel
design for disintegrating the soil fabric
(matrix) and solubilizing the
contaminant from the larger particles
(>2 mm) and an existing, but re-
engineered, four-stage countercurrent
extractor for freeing the contaminants
from smaller particles (<2 mm). The
processing rate of the system is 2.3 to
3.8 mVhr (4 to 5 ydVhr), though the
water-knife unit (used alone) can
process 11.6 to 13.5 mVhr (15 to 18
ydVhr). The complete system requires
auxiliary equipment, such as the EPA-
ORD physical/chemical treatment
trailer, to process the wastewater for
recycling; under some circumstances,
provision must be made to confine and
treat released gases and mists.
Treatment residues consist of
skimmings from froth flotation, fine
particles discharged with the used
washing fluids, and spent carbon. The
principal limiting constraint on the
treatability of soils is clay content (high
weight-percent), since breaking down
and efficiently treating consolidated
clays is impractical or not economically
attractive. Most inorganic compounds,
almost all water soluble or readily oxi-
dizable organic chemicals, and some
partially miscible-in-water organics can
be treated with water or water plus an
additive.
During limited laboratory extraction
tests, phenol was very efficiently
removed from both organic and
inorganic soils, whereas PCB and
arsenic clung more tenaciously to the
soils and were released less readily into
the washing fluids. The extent to which
the system has practical, cost-effective
utility in a particular situation cannot be
determined until preliminary, bench-
scale lab work has been performed and
acceptable limits of residual concentra-
tions in the washed soil are adopted.
Laboratory tests show that soil scrub-
bing has the capability of vastly
speeding up the release of chemicals
from soils, a process that occurs very
slowly under natural leaching
conditions.
Note that this system requires exca-
vation of the soil, which can subse-
quently be replaced or transported to a
low-grade landfill. In situ washing of
contaminated soil, a process in which
the contaminated area is isolated for
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example, by grouting, and then water-
flushed with removal of the wash water
at a well-point is an alternative. The
overall efficiency of the soil washing
system is greater than that currently
being achieved by in situ methods.
Based on the laboratory program, a
series of steps (water-knife size
reduction; soaking; countercurrent
extraction; hydrocyclone separation;
and waste fluid treatment for reuse)
was selected as the most suitable
process sequence for the prototype
system. The system was constructed
for the U.S. (EPA) and is now being
subjected to field evaluation. However,
soils rich in humus, organic detritus,
and vegetative matter can present
special problems in the extraction of
certain hazardous substances, which
may not partition between the solid and
fluid phases to a practical and necessary
extent.
This Project Summary was developed
by EPA's Municipal Environmental Re-
search Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The leaching of hazardous materials
from contaminated soils into ground-
water is recognized as a potential threat
to the Nation's drinking water supplies.
Such situations occur as the result of
accidental spills of hazardous substances
and from releases at the many uncon-
trolled hazardous waste disposal sites
now known to exist across the country.
Current removal/remedial technology is
largely limited to the excavation and
transfer of such soils to suitably sealed or
lined landfills where uncontrolled leach-
ing cannot occur.
Onsite treatment can be a more cost-
effective solution to the problem. In some
research projects, contaminated soils
have been isolated by injected grout,
trenched slurry walls, steel piling, etc.,
and then subjected to in situ leaching.
The effectiveness of such a process is
limited by, among many factors, the
permeability of the soil in its undisturbed
state. Economic and effectiveness factors
cannot be generalized but are situation-
specific.
An alternative process is needed for
those situations in which permeability or
other factors prevent effective in-situ
leaching and where landfilling is too
costly. The proposed technology — the
subject of the current effort — consists of
excavation, onsite but above-ground
treatment of the contaminated soil, and
return of the treated soil to its original
site.Excavation of the soil from its natural
state opens a number of options for
improved separation of contaminants
through better (high energyjmixing and
the potential for using different solvents.
Such cleanups can also be carried out
more quickly than they could by the
leaching of a more or less compact
natural soil (cost factors not being consid-
ered). This engineering approach has also
made it possible, or more convenient, to
incorporate any control devices that may
be needed to reduce emissions of particu-
lates or fumes into the air column and/or
to treat the contaminated wastewaters
generated during the processing.
The purpose of this project was to carry
out appropriate laboratory studies and to
develop, design, and construct a full-
scale system capable of treating a wide
range of contaminated soils. The existing
system will be useful for the correction of
long-standing (remedial) contamination
problems (waste disposal sites), as well
as for the emergency cleanup of spills and
for the prompt removal of released
wastes.
Discussion
To meet the objectives of the program,
specific criteria were identified for the
solvent, the soils, the pollutants, and the
process.
To be suitable for field use in such a
process, the solvent or extracting fluid
should have the following characteristics:
1. A favorable separation coefficient
for extraction,
2. Low volatility under ambient condi-
tions (to reduce air contamination
effects),
3. Low toxicity (since traces of
extractant may remain in the
cleansed soil),
4. Safety and relative ease of handling
in the field,
5. Recoverability for reuse.
The selected solvent must be able to
separate the contaminant from the soil,
preferably using a minimum volume of
solvent so that the equipment can be kept
compact. In addition, the solvent must be
readily separable from the soil fines to
allow return of the decontaminated soil to
the site and to permit treatment and
reuse of the solvent. High volatility in the
solvent can contribute to unacceptable
losses and can, when coupled with
flammability, exacerbate health and
safety risks for the workers.
Following a brief evaluation and
screening of potential solvents (including
organics), consideration of all the above-
cited factors clearly indicated that water
was suitable as the primary target
solvent. The use of additives such as
acids or bases, oxidizing or reducing
agents, or wetting agents was judged to
be a reasonable approach for enhancing
removal efficiency. Though certain
organic solvents can meet most of the
solvent criteria and may have definite
advantages in specific cases, a decision
was made early in the project to limit the
investigation to water-based systems.
The range of soils that is encountered
in a cleanup situation is very broad,
encompassing fine, highly cohesive clays,
sandy soils, silts, soils high in organic
matter, etc. Though processes can be
devised to handle any or all of these
materials, certain contaminated soils do
not require exhaustive extraction and
others do not lend themselves to an
extractive process. The organic content of
a soil can affect the ease of size reduction
and the efficiency of extraction. The pH of
a soil can affect the extraction efficiency
for a particular contaminant. When the
soils and contaminants have catonic or
anionic qualities, ion exchange (partition
factors cannot be neglected.
For purposes of this investigation, two
soils were selected as suitable represent-
atives of many that might be encountered.
These were a granular (sandy),
essentially cohesionless inorganic soil
(containing some fine sand and about
20% clay) and a highly organic (18.4%,
mostly as peat and humus) commercial
topsoil.
Though spill situations and waste
disposal sites may differ in many ways
(such as the portion of a contaminant that
is tightly bound to the soil versus the
amount loosely associated in the voids),
plans for the test program emphasized
the spill situation by using freshly
prepared mixtures of soil plus
contaminant. Funding was insufficient to
support work with aged or weathered
contaminated soils that are more repre-
sentative of dumpsites.
The actual process for the planned
system must include excavation and
transfer to the processing equipment,
screening to remove large (>2.5 cm)
-------
objects, size reduction to maximize soil-
solvent contact, extractive treatment,
separation of contaminated solvent from
(relatively) decontaminated soil particles,
and return of the soil (either "as is" or
after drying) to the excavation.
Excavation can be readily handled by
conventional earthmoving and
construction machinery. Size reduction
of soils can be accomplished with
various, commercially available
equipment, including rotary scrubbers,
log washers, attrition scrubbers, and
high intensity water-knives. The
properties of each were considered, and
the water-knife was chosen as the most
versatile unit; it was also suitable for both
disintegrating clay-like lumps and for
scrubbing the loosely held contaminant
from the resulting smaller (>2 mm)
components.
For the decontamination process to be
effective with a wide range of water-
insoluble and tightly held contaminants
on small particles (>2 mm), follow-on
multi-stage extraction was judged to be
necessary. The use of countercurrent
extraction allows several stages of
extraction with minimum solvent use.
Clearly, the final system also requires
equipment to separate fines from the
solvent, both between extraction stages
and after the last stage. Gravity
separators, clarifiers, and filters were
generally inappropriate for the planned
system; hydrocyclones were selected for
evaluation.
The three hazardous contaminants
selected for testing were phenol, arsenic
trioxide, and PCB's. These were chosen
because of the frequency with which they
are encountered in spills and the range of
physical and chemical characteristics
they offer. Laboratory tests were carried
out to assess the effects of different
water-based solvents and different pro-
cessing conditions on these three
chemicals mixed with the two soil types
noted earlier. The results of these studies
were then used to design the full-scale
prototype.
Equipment Evaluation
Size Reduction and Extraction
A series of tests was conducted with
the water-knives, first using a local, avail-
able, uncontaminated soil sample.
Numerous approaches to exposing the
soil to the water-knife jets were tried and
abandoned (refer to the full report). Only
when the soil was contained in a
truncated, cone-shaped, tilted rotary-
screen drum (2-mm mesh openings) was
the desired lump breaking obtained. The
first tests were performed in an 18-in.
trash basket (top ID = 15 in.; bottom ID =
12 in.) in which 50% of the bottom
sidewall (up to 8 in.) was cut away in four
sections that were overlain with various
mesh" screens. (The device was re-
engineered for the actual testing.) In the
bench apparatus, approximately two-
thirds of the soil was washed out through
the screen within the first 2 min of
treatment with4.5L/min(1.2 gal/min)of
water at a pressure of 4.9 kg/cm2 (70 psi)
and a drum speed of 10 to 20 rpm. Further
experiments indicated that a three step
sequence was needed to achieve the best
decontamination:
1. Low-pressure wash,
2. Soaking, followed by stripping, and
3. Low-pressure fresh-water wash.
Liquid-Solid Separation
To study the separation of soil fines
from water, a full-sized hydrocyclone
(227 L/min) was used with different
inflow rates (and pressures) and different
concentrations of both soils. Though the
results of these tests show that the
hydrocyclone is suitable for each soil,
they also indicate that the solids were
better concentrated in the underflow
from the inorganic soil. With both soils,
the overflow contained a small but
significant amount of fines (0.7% to 3.7%),
which would require additional separation.
Passing this overflow through the
hydrocyclone in a second treatment was
not notably effective in removing these
fine solids.
Because the hydrocyclone was too
large for routine use in the laboratory
study of contaminant removal from soil,
simply gravity settling in a beaker was
evaluated and found to represent a good
simulation of the separation achievable
with the hydrocyclone.
Extraction Tests
Tests were carried out with the three
chemicals (all three were not used in all
experiments) to establish the following:
a) probable loading on a soil column,
b) distribution on particles of different
sizes, and
c) effect of extraction with different
sovents on particles of different
sizes.
Column Loading Studies
A stock solution of the contaminant
equal in volume to the void space in the
column was added to a 15.2-cm (6.0-in.)
column of soil (various moistures and
densities) and allowed to drain for 24 hr.
The contaminant remaining in the
column was calculated on a dry weight
basis, based on the amount of fluid that
drained from the column. Modified gas
chromatographic and atomic absorption
methods (described more fully in the
report) were used. Results obtained with
the three materials are shown in Table 1.
Note the heavy loading of phenol, which
represents the situation that might exist
shortly after a spillage onto soil.
Distribution Tests
Different procedures were used with
phenol and with arsenic trioxide to evalu-
ate their distribution on particles of
different sizes. For phenol, dry soils were
first size-classified with a sonic fraction-
ation device. Each fraction was then
wetted with a stock solution of phenol.
After 18 hr, the fractions were rinsed
with water and analyzed. For arsenic, the
soil from the column dosing tests was
dried, size fractionated, and then
analyzed. High recoveries (based on
analyses) were achieved in both cases.
With phenol, these tests indicated that
approximately 90% of the contaminant
was absorbed (or retained interstitially)
on the larger particles (0.6 to 2 mm*) of
the organic soil. These somewhat
unexpected results also appear to be a
consequence of nonuniform distribution
of organics in the different particle-size
fractions. Tests confirmed that the fine
particles contained predominantly
organic degradation products rather than
plant tissues, which remained primarily
with the larger particles. Such
differences may make it necessary, in
some cases, to presoak the soil for
efficient extraction.
Unexpected results were also obtained
when testing the distribution of phenol on
the inorganic soil. The relatively low
adsorption by the finer particles was
attributed to differences in internal
porosity and chemical composition
between the large and small particles
rather than the proportionately greater
surface area (calculated on a weight
basis) of the fine particles.
The results obtained with arsenic
trioxide on the organic soil were similar to
those obtained with phenol. With the
1 Nominal sizes are given for screens.
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inorganic soil, however, the arsenic
compound exhibited the normally
expected relationship between particle
size (i.e., surface area) and amount
adsorbed. That is to say, because of the
greater surface-to-mass ratio, more
adsorption occurs per unit weight of fines.
PCB's were not tested to any great
extent because of their low solubility and
the hazards involved in working with
them. Time and funding constraints also
influenced this decision to curtail PCB
studies.
Water-Knife Stripping Tests
Contaminated soil samples were
subjected to 1 min of stripping by the
water knife to remove particles smaller
than 2 mm. Residual contaminants on the
remaining (larger than 2 mm) particles
were then determined. The results (Table
2) show the value of additional washing
or extraction, at least for phenol and
arsenic trioxide.
Chemical Extraction Tests
Since water is not the optimum extract-
ant for all contaminants tested, and since
most of the contaminants will be
absorbed by and adsorbed on the smaller
(<2 mm) particles, a series of tests with
the following aqueous solutions was
conducted to determine whether
extraction efficiency could be improved:
water + sulfuric acid to pH 1
water + sodium hydroxide to pH 11
water + 7.5% sodium bisulfate
water + 5.0% sodium hypochlorite
water + 1.0% TWEEN 80
water + 1.0% MYRJ 52
water + 5.0% methanol
For the inorganic soils contaminated
with phenol, all extractions were highly
efficient, with removals greater than
87%. Only for the organic soil could the
difference between solvents be
considered significant, with the sodium
hydroxide solution being the most
effective solvent. A portion of the data
presented in the report is summarized in
Table 3. The relative and actual
importance of the residual contaminant
on the soil should not be ignored, nor
should the fraction of solvent remaining
in the soil (not shown in Table 3). When
the residual level of contamination is
Table 1. Maximum Column Loadings
Contaminant
Organic Soil
fmg/g soil)
Inorganic Soil
(mg/g soil)
Phenol
Arsenic trioxide
PCB
453.2
5.0*
25.6
48.3
0.75*
3.0
*As arsenic (As).
Table 2. Effect of Washing on Large Particles'
Soil
Inorganic
Organic
Test
Time
(min)
15
30
60
120
15
30
60
120
Phenol
97.9
98.2
98.8
99.1
60.7
79.2
86.0
91.6
% Removal
As203
28.9
52.1
42.2
52.1
47.7
55.8
54.0
59.0
PCB
21.4
50.0
21.4
28.6
*2 to 12.7 mm
Table 3. Solvent Extraction: Representative Single- Washing Tests*
Contam-
inant
Phenol
Asi03
PCB
So//**
/
O
1
O
1
0
Solvent
Water
Water
NaOH (pH 1 1)
Water
H2SOt fpH 1)
Water
H2SOt fpH 1>
Water
1% 7 ween 80
Water
1% Tween 80
Initial
Soil Dose
(mg/g dry
soil)
48
452
0.75
5
3
26
%
Removal
98.6
77.8
88.4
42.7
85.3
75.0
85.0
24.6
37.5
48.3
23.8
Supernatant
Concentration
(mg/L)
1,190
17,600
20.000
16
32
375
425
72
110
418
366
Residual Soil
Concentration
mg/g
0.68
100.4
52.5
0.43
0.11
1.25
075
2.66
1.88
13.2
19.5
* Extractant to dry solids 10:1 (w/w).
** I = inorganic; O = organic.
sufficiently low, the treated soil may no
longer require disposal as a hazardous
material, e.g., in a safe landfill.
Samples of phenol-contaminated
organic and inorganic soils were also
subjected to multiple extractions. These
tests demonstrated that continued
removal of phenol did occur, even when
the extractant was recovered solvent
(water) from a previous stage and already
contained phenol. Residual phenol
concentrations of 30 mg/kg (0.03 mg/g)
of soil were achieved after four
countercurrent extractions of the
inorganic soil.
Prototype Design and
Construction
The process sequence for full-scale
treatment (Figure 1) was finalized, based
on the laboratory experiments. The
sequence includes initial removal of
oversized chunks (>2.5 cm), water-knife
-------
scrubbing to deconsotidate the remaining
soil matrix and to strip any contaminant
loosely absorbed on the solids(>2 mm) or
held in the void spaces of the soil, and
four-stage, countercurrent extraction
coupled with hydrocyclone separation
after each extraction stage to separate
the solids (<2 mm) from the liquid. Froth
flotation is used to give maximum mixing
of extractant and soil in each stage. The
overhead extract (mostly sorbent) from
the first stage extractor hydrocyclone
contains the highest level of dissolved (or
dispersed) contaminants and fines. This
extract must be clarified and then treated
(possibly with activated carbon) before it
is recycled.
Note that: chunks (> 2.5 cm) are not
normally processable in the system
except for moderate washing on a bar
screen*; the 2.5-cm to 2-mm as well as
the <2-mm fraction, will be used to fill in
the excavation; all processing fluids must
be appropriately treated. All dust and
vapor emissions should be ducted to an
air cleaner or scrubber before discharge.
The basic system was constructed
according to the design shown in Figure 1.
The water-knife unit (rotary drum-
screen scrubber) consists of a tilt-skip
loader and hopper feed from which the
soil moves into a tillable 19-m (21 -ft) long
by 1.4-m (4.5-ft) ID cylinder fitted with
end pieces, water-knives, and a rotating
mechanism (Figures 2, 3, and 4).
Soil is metered from the tilt-skip
reservoir hopper at rates up to 18 ydVhr
onto a manually washed bar screen
where >2.5-cm (1-in.) chunks are
rejected. The solids then pass into the
tilted drum-screen scrubber where it is
subjected to first-stage water-knife strip-
ping, water soaking, and finally second-
stage water-knife stripping using fresh or
partially recycled water. The first section
of the scrubber cylinder is 1.3-m (4-ft)
long and is fabricated from 2-mm mesh
(HYCOR Contra-Shear screen) and
equipped with internal water-knives.
Solids then move into the 5-m (15 ft)
soak cylinder that is fitted with a baffle
plate that has a 0.5-m (22-in.) center
opening through which solids pass into a
0.7-m (2-ft) long screened, water-knife
rinse zone. Fines (<2 mm) pass through
the screens, as does the wash water. The
coarse particles are voided at the end of
+2 mm Scrubbed Soil
* There are two bar screens. The soil is hosed-reused
on a 7.5- or 5-cm (3- or 2-in.) upper screen in the
skip-hopper from which large or nondisintegrable
chunks are raked off. Washed chunks that pass the
upper screens are rejected and removed at the
second (lower) bar screen (<2.5 cm [1 in.]).
Contaminated
Soil
Counter-Current
Chemical
Extractor
Oversize
Non-Soil
Materials
and Debris
Figure 1.
Makeup Water
Spent Carbon
Process flow scheme for soil scrubber.
Figure 2. Fully constructed rotary drum screen scrubber.
the drum. The unit can be backflushed as
needed. The screens resist buildup of
fines (blinding). The actual arrangement
of the water-knives and other details of
construction are given in the project
report.
From the water-knife and soaker unit,
the slurry (<2-mm particles) is pumped to
the countercurrent extractor. The four-
stage countercurrent extraction unit
(Figures 5 and 6) has been modified from
the so-called EPA beach sand froth
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Metering Hopper
Tilt Skip
Hopper up to
Load Metering
Hopper
Drum-Screen
Soil Scrubber
Hand Wash
Large
Stones
Figure 3. Soil loading and metering system (cross sectional side view).
Initial
Spray Zone
Soil In
Outer Shell
A. Drum cross section
,~ 16 Inches
Baffle
Soil Surface
Inner
Cylinder
Figure 4.
Soak Zone
Channel Formed by Screen
Soil and Drum Wall
B. Drum Isometric
Soak zone description.
6
flotation unit.* Basically, the washing
chamber was partitioned into four
sections (3-ft long X 4-ft wide X 5-ft
deep), each of which has an aerator
agitator and a hydrocyclone with pumps
and piping. Flow of solids (<2mm) and
fluid is countercurrent with clear water
being introduced at the fourth (discharge)
chamber (Figure 6). The extraction unit
has an on-board diesel generator; the
water-knife unit requires external power.
The underflow (solids-rich) slurry from
the fourth hydrocyclone is discharged to a
drying bed.
To achieve mobility, the water-knife
unit is skid-mounted for transport by
semi-trailer; the countercurrent extractor
is integrally attached to a separate semi-
trailer. Refer to Figures 2 and 5 for details.
Calculations indicate that the total
system has a throughput range of 2.3 to
3.8 mVhr (3-5 ydVhr), but that the
water-knife unit alone can process 11.5
to 13.5 mVhr (15 to 18 ydVhr).
Conclusions
The following conclusions can be
drawn from the work carried out during
this program and the knowledge gained
during that effort:
1. Spill-contaminated soils can be
excavated and treated onsite using
extraction with water or aqueous
solutions for many pollutants that
are frequently encountered in such
situations.
2. A system capable of decontamina-
ting 2.3 to 3.8 mVhr (3-5 yd'/hr) of
soil has been designed and
constructed and it is now available
for field testing by EPA.
3. Water-knives function as a compact,
efficient, and economical means or
achieving effective contact between
contaminated soil particles and
extractant.
4. Countercurrent extraction is an
effective process for removing
certain adsorbed contaminants
from soils and, for the size of
equipment needed, hydrocyclones
are preferred devices for separating
the extracted solids from the ex-
tractant.
'Garth D. Gumtz, Restoration of Beaches Contamin-
ated by Oil. EPA-R2-72-045 (Washington, D.C.: US
EPA, 1972).
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5. Laboratory experiments demon-
strate that soil characteristics
(particle size, distribution, organic
content, pH, ion-exchange proper-
ties, etc.) are important factors in
the removal or retention of
contaminants.
6. In addition to the actual percentage
of the contaminant removed, the
allowable level of pollutant
remaining in the soil is an important
factor in determining when
adequate decontamination has
been achieved since the final,
residual concentration affects the
options available for disposal of the
cleansed solids.
Recommendations
Based on the observations made during
this' investigation, several suggestions
are offered for future work.
1. Laboratory screening tests should
be performed on a wider range of
typical compounds and mixtures
encountered in hazardous
substance spill and release situa-
tions to ensure that appropriately
high levels of decontamination can
be achieved with this process.
2. The results of this study apply pri-
marily to spill situations. Contami-
nated soils found at waste disposal
sites may exhibit different
extraction characteristics because
of the extended soil/contaminant
contact time and of weathering and
in situ reactions. Studies are needed
to establish whether and to what
extent such changes affect the
decontamination process.
3. Other extractant solutions should
be evaluated to determine whether
the efficiency of the process can be
improved without damaging the
equipment or increasing the
hazards to which the workers are
exposed.
4. A wider range of soils should be
examined to determine what
changes in the system are practical
to better cleanse soils with charac-
teristics (e.g., greater cohesiveness
and adsorptive properties of clay-or-
silt-rich soils) that differ signifi-
cantly from those of the soils already
tested.
Figure 5. EPA Froth Flotation System (beach cleaner) modified as a countercurrent
chemical extractor for soil scrubbing.
Chemical
Additive
(If Needed)
Spent
Washing
Fluid
Raw
Feed
Chemical
Additive
(If Needed)
Chemical
Additive
(If Needed)
J
Fresh
Water
Slurry Pump
Figure 6. Process flow scheme for soil scrubber.
The full report was submitted in
fulfillment of Contract No. 68-03-2696 by
Rexnord, Inc., under the sponsorship of
the U.S. Environmental Protection
Agency.
Clean
Product
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Robert Scholz and Joseph Milanowski are with Rexnord Inc., Milwaukee. Wl
53214
John E. Brugger is the EPA Project Officer (see below).
The complete report, entitled Mobile System for Extracting Spilled Hazardous
Materials from Excavated Soils." (Order No. PB 84-123 637; Cost: $11.50,
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:
Municipal Environmental Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
US.
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US GOVERNMENT PRINTING OFFICE 1984-759-102/819
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