United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-211 Oct. 1981
Project Summary
Use of Selected Sorbents
and an Aqueous Film
Forming Foam on Floating
Hazardous Materials
Michael K. Breslin and Michael D. Royer
Research was conducted to deter-
mine the effects of sorbent materials
and fire-fighting foam on containment
recovery, and vapor suppression of
floatable hazardous material spilled on
water.
The tests, which were performed at
the U.S. Environmental Protection
Agency's (EPA) Oil and Hazardous
Materials Simulated Environmental
Test Tank (OHMSETT), made use of
the Clean Water, Inc., Harbour Boom
and the Industrial and Municipal
Engineering Swiss OELA III Skimmer.
These devices were also used in a
1975 EPA study, and results of both
test programs are compared in this
report.
Critical tow speed of the boom
(speed at which hazardous material
loss began), fluid recovered by the
skimmer, and hazardous material
vapor concentration were measured
as functions of type of material, tow
speed, type of sorbent, presence of
foam, and wave condition. Test
results were evaluated by comparing
them with those obtained using pure
hazardous material (i.e., no sorbent or
foam).
Oioctyl phthalate (OOP), octanol,
and naphtha served as the hazardous
materials. The sorbent materials were
polyurethane foam cubes; Clean
Water, Inc., Sorbent C; and Dow
Chemical Co. Imbiber Beads. An
aqueous film forming foam (AFFF),
FC-206*, from the 3M Company was
used.
This Project Summary was devel-
oped by EPA's Municipal Environ-
mental Research Laboratory, Cincin-
nati, 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
Large quantities of hazardous materi-
als (HM) are constantly being handled
by inland and marine tranportation and
support equipment. Spills during transit
or at producer and user storage facilities
pose a serious threat to the health and
welfare of the general public and
environment. The study summarized
here investigates the possibility of
enhancing present containment and
recovery techniques for spills of floating,
immiscible HM. Several concepts were
considered feasible:
1. Increasing the cohesiveness of
spilled HM to stave off shedding
and splash-over losses from a
boom (see Figures 1 and 2),
2. Absorbing the HM into a more
buoyant material to reduce sub-
•Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use
-------
Current
Losses
Oil
Figure 1. Hazardous material shedding failure and entrainment under a boom.
Losses
Current
Oil
Figure 2. Hazardous material splash-over failure over a boom.
mergence and shedding beneath a
boom, and
3. Covering the sorbent and haz-
ardous material with fire-fighting
foam to decrease HM vapors
above the slick.
The purpose of this project was to
investigate the effectiveness and prac-
ticality of the above-mentioned concepts
in a simulated field-environment. Tests
were performed at the OHMSETT
facility with the use of three sorbents
(foam cubes, Sorbent C, and Imbiber
Beads) and fire-fighting foam in con-
junction with the Clean Water, Inc.,
Harbour Boom and the Industrial and
Municipal Engineering (IME) Swiss
OELA III Skimmer on simulated spills of
three hazardous materials (octanol,
naphtha, and dioctyl phthalate). The
critical tow speed of the boom, the
amount of fluid recovered by the
skimmer, and the HM vapor concen-
tration above the slick were measured
as functions of type of HM, tow speed,
type of sorbent, pressure of foam, and
wave condition. Test results were
evaluated by comparing them with
those obtained using pure HM (i.e., no
sorbent or foam).
Test Plan
To compare the tests conducted in
this program with the 1975 hazardous
materials program, a test matrix was
written to duplicate the previous
program with the addition of sorbents
and fire-fighting foam. Control tests
without sorbents or foam were con-
ducted for a basis of comparison with
the 1975 tests. As the program pro-
ceeded, certain tests were eliminated
from the matrix. The test with sorbent
and AFFF in the harbor chop mode were
deleted, as were tests employing the
diversionary configuration of the boom.
Equipment
The OHMSETT is located in Leonardo,
New Jersey, and is operated by EPA. The
primary feature of the facility is a pile-
supported, concrete tank that is spanned
by a bridge capable of towing floating
equipment. The principal systems of the
tank include a wave generator, a beach,
and a filter system. The wave generator
and absorber beach can produce regular
waves as well as a series of high-
reflecting, complex waves meant to
simulate the water surface of a harbor
or the sea. The tank water is clarified by
recirculation through a filter system to
permit full use of a sophisticated
underwater photography and video
imagery system.
The Clean Water, Inc., Harbour Boom
was essentially the same boom used in
the 1975 tests; however, the skirt depth
was increased from 57 to 61 cm, and the
length was shortened from 60.5 to 40.5
m. The ends of the boom were bolted to
the tow points of the main bridge,
forming a catenary configuration under
tow.
The IME Swiss OELA III Skimmer was
selected for this test because of its use
in the 1975 test and its availability.
A double-diaphragm. Warren Rupp
Sandpiper pump (Model SA-3A, Type
DA2-A) was used until clogging problem
occurred. A 5.1-cm inlet/outlet Barnes
rotary pump was subsequently em-
ployed. Except for priming problems
when the skimmer emptied, it performed
satisfactorily without clogging.
Clean Water, Inc., Sorbent C is a
fibrous, oil-absorbing material that is
buoyant in water even when fully
saturated with oil. This material is
comparable with that used in acoustic
ceiling tiles. Sorbent C is supplied
shredded and contains a considerable
amount of fine dust. Dow Chemical Co.
Imbiber Beads are 7-mm spheres of
cross-linked, t-butylstyrene polymer
that absorb and retain hydrocarbons.
The beads are oleophilic, hydrophobic,
and very buoyant.
The foam sorbent consisted of 1.9-cm
cubes of reticulated, open-cell, 31
pore/cm, quenched polyurethane This
type of foam cube was found to be
durable and effective in absorbing
hydrocarbons in previous tests at
OHMSETT.
A gasolme-engine-powered centrif-
ugal blower with a 3-m long, 20-cm-
dia meter flexible hose was used to apply
the Sorbent C, Imbiber Beads, and foam
cubes. Originally, a rotary lawn fertililzer
(vertical spreader axis) was used to
distribute the Imbiber Beads by con-
necting a 1/4-inch variable speed drill
to the wheel axle. The centrifugal
blower distributed beads farther and at
a greater rate.
FC-206, an aqueous film-forming
foam (AFFF) produced by 3M Company,
was employed. A standard mixing
nozzle connected to a fire hose produced
a stream that shot about 6m and formed
a 7.6-cm-thick blanket of foam.
The hazardous materials selected for
testing (naphtha, OOP,and octanol)
represented a wide range of three
important physical properties—viscosity,
specific gravity, and interfacial tension.
They were also selected for their low
toxicity and flammability. The same
fluids were used in the 1975 test
program, but in larger amounts (1.325
m3 per test versus 0.38 m3).
Cameras provided visual documenta-
tion of test layout, equipment, and
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performance characteristics. A black
and white TV camera in a waterproof
case with a video recorder provided
underwater coverage. Two 16-mm
movie cameras and a 35-mm slide
camera were employed for topside and
tankside window coverage.
To detect and determine vapor con-
centration, a Miran 1A Gas Analyzer
and an Esterline Angus Mini-Servo
strip-chart recorder were used with two
filtered air intakes. One was mounted
on the main bridge just above the water,
and the other was positioned on the
auxiliary bridge on a pivot mount that
could be swung tofollowthe boom apex.
Two 1/2-inch (12.2 cm) valves were
used to switch from one intake to the
other.
Test Procedures
The boom was connected to the
towing bridge and set in motion at 0.5 kt.
The HM, stored in tanks on the main
bridge, was distributed into the boom
from the front of the main bridge. As the
test continued, sorbent and/or foam
was distributed onto the slick as it was
passed over by the rear side of the
bridge. The boom speed was increased
until failure (i.e., HM loss from the
boom) was observed, decreased until
failure ceased, and then increased
again to confirm the failure speed. This
speed was recorded as the critical tow
speed. (When OOP was used as the HM,
the tow speed had to be decreased
below 0.5 kt for the critical tow speed
determination.) Certain tests were
repeated with the same charge in the
boom to observe the effect of longer
mixing and absorption time.
Sorbent C and foam cubes were
distributed until about three-fourths of
the slick was covered, which required
16.36 kg of Sorbent C and 0.22 m3 of
foam cubes. For Imbiber Bead applica-
tion, a 1:10 ratio was used with OOP
and octanol, and a 1:20 ratio with
naphtha. The fire-fighting foam was
distributed until the slick was covered.
Following boom tests with Sorbent C
and Imbiber Beads, skimmer tests were
conducted. The HM/sorbent in the
boom was directed to the skimmer with
fire hoses, and the recovered material
was pumped to polyethylene collection
barrels. After a sufficient settling period
(2 hr), liquid levels in the barrels were
measured. The sorbent and HM were
mixed, sampled, and analyzed for oil,
water, and solid content.
The use of sorbents prevented the
continuous flow of HM into the skimmer
during calm water tests and necessi-
tated the use of a boat hook to keep the
skimmer weir submerged. Because of
potential clogging problems, it was not
feasible to use the skimmer to collect
the foam cubes. Instead, they were
recovered by nets after the test and
hydrauhcally squeezed for reuse in
subsequent tests.
The HM vapor was continuously
sampled and analyzed for hydrocarbons
during each test. The sample intake on
the main bridge was used when the HM
was initially distributed. After the foam
and/or sorbent had been applied, the
sample was drawn from the intake on
the auxiliary bridge over the boom apex.
The two readings were compared to
measure sorbent/foam effects on HM
evaporation.
Results
Results of the boom tests are sum-
marized in Figures 3 through 7. The
effects of sorbents and foam on critical
tow speed are clearly indicated. In
addition, the boom performance on pure
HM may be compared with the 1975
test results.
For pure HM, higher critical tow
speeds were measured in these tests
than in 1975. This result can be
attributed to the larger amount of HM
used in 1975, to the different method of
attaching the boom to the towing bridge,
and to the subjective decisions on the
degree of HM loss constituting boom
failure
The foam cubes increased the critical
towing speed substantially for both OOP
and naphtha, but then had little effect
with the octanol (see Figures 3 through
5). The spaces between the cubes
tended to trap the HM and prevent
shedding. Through the subsurface
windows, it was seen that the under-
water portion of the cubes prevented
the interfacial shearing force from
reaching the HM.
The results obtained when employing
Sorbent C showed an increase in the
boom's ability to retain HM. The
suspension of fibers in a liquid can
reduce turbulent drag, which causes
the formation and release of oil droplets
at the oil/water interface. The product
also acted as a buoyant sorbent that
prevented shedding.
The Imbiber Beads performed best on
OOP and worst on naphtha. Given
enough Imbiber Beads and a sufficient
residence time, the HM slick could have
been made into a solid buoyant sheet.
Such a procedure would be impractical
in field use, however, because of the
large number of beads required.
Some test results indicated that a
higher critical tow speed is attainable
1.0r-
\ I Test conducted using designated agent with foam
\ I
1975
Test conducted using designated agent with foam
Critical Tow Speed fm/s)
P P c
*» O> b
0.2
0
1
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X
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X
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Figure 3.
None None Cubes Sorbent C Beads
Sorbent or Congealing Agent
Clean Water boom performance in calm water using naphtha.
3
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1.0 r-
08
£ 0.6
& 0.4
0.2
I I Test conducted using designated agent with no foam
Test conducted using designated agent with no foam
1975
Test
1977 Tests
I
X
X
X
X
X
X
None None Cubes Sorbent C
Sorbent or Congealing Agent
Figure 4. Clean Water boom performance in calm water using OOP.
Beads
using AFFF and sorbent rather than
sorbent alone. Perhaps the foam causes
the sorbent to become wetter or to
absorb more oil.
The results obtained using the IME
skimmer are very operator-dependent,
which makes an overall comparison of
the tests difficult. The use of sorbents
did substantially reduce HM and water
emulsification. The skimmer test with
pure octanol resulted in a water content
of 26%. Water contents in samples from
test runs with Sorbent C and Imbiber
Beads were 3.6% and 7.25%, respec-
tively.
OOP and octanol have low vapor
pressures. The differences in vapor
concentration at the two sample points
were very small and were far outweighed
by the experimental variations resulting
from wind and temperature effects,
filter clogging and contamination, and
shape of slick. The naphtha results
consistently indicate that the vapor
concentration above the slick was
higher following the addition of sorbent;
but the results do not necessarily
indicate that the addition of the sorbent
was the cause of the increase. Thus, no
conclusions were drawn from the vapor
concentration studies.
1.0 -
Test conducted using designated agent with no foam
I Test conducted using designated agent with foam
0.8
\
5
/ Tow Speed
p
b>
•S 0.4
Cj
0.2
n
1975 ^
Test
h
—
_
—
j
1977 Tests
\
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x
X
x
x
X
X
X
X
X
None None Cubes Sorbent C
Sorbent or Congealing Agent
Beads
Figure 5.
Clean Water boom performance in calm water using octanol.
4
Conclusions
The following conclusions were
drawn from the evaluation of the test
data and observations of equipment
performance:
1. Introducing sorbents or congealing
agents into the HM enables a stable
boom to contain the material at a
higher current velocity or tow speed
in calm water.
2. The polyurethane foam cubes were
most easily distributed and accounted
for later.
3. To optimize the effect of sorbents,
time for mixing and absorption of HM
must be allowed. The time required
varies with wave condition and
turbulence.
4. Because of splash-over failure,
neither the sorbents nor the Imbiber
Beads enhanced containment in the
presence of 0.3-m harbor chop.
5. Application of sorbents to a floating
HM spill is possible with the use of a
simple blower-type distributor, such
as those used to distribute wood
chips or straw in landscaping opera-
tions.
6. Cleanup effort (e.g., sorbent acqui- .
sition, transportation, distribution,
collection, separation, recycling, and
-------
o.io
0.08
to
"g 0.06
I
fi
0.04
0.02
0.00
7975
Test
h
Test conducted using designs ted agent with no foam
7977 Tests
I
None Cubes SorbentC Beads
Sorbent or Congealing Agent
Figure 6. Clean Water boom performance in harbor chop using naphtha.
0.1 Ot-
008
0.06
0.04
0.02
0.00
n
Test conducted using designated agent with no foam
1977 Tests
I
_ r
Cubes SorbentC Beads
Sorbent or Congealing Agent
disposal) was substantially increased
as a result of the use of sorbents.
7. Some test results indicate that a
higher criticaI tow speed is attamable
using AFFF and sorbent rather than
sorbent alone.
Recommendations
Careful study should be given to the
safety aspects and the disposal, storage,
and refurbishing of sorbents used to
recover HM. Although the concentration
of vapors above an HM slick does not
increase appreciably when solvent is
added, the HM will rapidly evaporate
from the sorbent after recovery, creating
an air pollution or explosion hazard.
Although the polyurethane foam
material was not expensive ($0.50/m2),
the cutting of the cubes was. Use of a
larger cube is therefore recommended
to decrease cube-cutting costs.
The resource costs associated with
acquisition, transportation, distribution,
collection, separation, recycling, and
disposal of sorbents are significant and
must always be considered before using
sorbents to enhance floating HM
recovery.
The full report was submitted in
fulfillment of Contract No. 68-03-0490
by Mason & Hanger-Silas Mason Co.,
under the sponsorship of the U.S.
Environmental Protection Agency.
Figure 7. Clean Water boom performance in harbor chop using OOP
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Michael K. Breslin is with Mason and Hanger-Silas Mason Co., Inc., Leonardo,
NJ 07737- Michael D. Royer is the EPA author with the Municipal Environ-
mental Research Laboratory, Edison, NJ 08837.
John S. Farlow is the EPA Project Officer (see below).
The complete report, entitled "Use of Selected Sorbents and an Aqueous Film
Forming Foam on Floating Hazardous Materials," (Order No. PB 82-108 895;
Cost: $8.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Oil and Hazardous Materials Spills Branch
Municipal Environmental Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
U. S. GOVERNMENT PRINTING OFFICE: I98I/559-092/3335
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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