vvEPA
United States
Environmental Protection
Agency
Municipal Environmental Research _
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-088 Nov. 1982
Project Summary
Testing Truck-Mounted
Vacuum and Air Conveyor
Systems for Oil Spill Recovery
Donald C. Gates and Kevin M. Corradino
Two types of vacuum oil recovery
systems were performance tested at
the U.S. Environmental Protection
Agency (EPA) Oil and Hazardous
Materials Simulated Environmental
Test Tank (OHMSETT) in September
1980. A Vactor Model 2045* air
conveyor made by the Meyers-Sherman
Company and a straight vacuum truck
made by Coleman Environmental and
Pollution Control Equipment Co.,
Inc., were evaluated for oil recovery
performance using recovery efficiency
and oil recovery rate. Changes in
recovery efficiency and oil recovery
rate were found with varying oil slick
thickness, oil viscosity, hose length,
and blower speed. The air conveyor
was also tested using different dis-
tances between the slick and the
suction hose.
Air conveyor results showed a mean
recovery rate of 7.2 m3/hr with a 61 %
oil recovery efficiency (4.4 m3oil/hr).
Efficient recovery of thin oil slicks is
the main advantage of air conveyors.
Vacuum truck tests produced a mean
oil recovery rate of 13.3 mVhr of an
18% oil fluid (2.4 m3 oil/hr). Vacuum
trucks seem particularly suited for use
with thick slicks and with skimmers to
increase recovery efficiency. Vacuum
trucks would also be effective for
transferring recovered oil from primary
recovery devices to final storage or
reclamation sites.
'Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory. Cincinnati. OH.
to announce key findings of the
research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Vacuum systems are one of the most
commonly used pieces of equipment at
oil spills. They are mobile, simple to
operate, complete skimming systems.
Two types of vacuum systems are
available — air conveyors and vacuum
trucks. Air conveyors use a large-
diameter hose (typically greater than 1 5
cm) and a high volume of air to convey
material into a tank. A schematic
drawing of an air conveyor system is
shown in Figure 1. Air conveyors
require that the suction hose inlet
remain above the material being picked
up so that an adequate air flow can be
maintained. Vacuum trucks use a
smaller-diameter hose (typically 7.6 cm)
and a low-volume blower to evacuate a
truck-mounted tank (Figure 2) The hose
inlet must be placed in or on top of the
material being recovered, as the air flow
in the hose is not sufficient to air-convey
material up the hose.
Each of these systems was tested at
the U.S. Environmental Protection
Agency (EPA) Oil and Hazardous Material
Simulated Environmental Test Tank
(OHMSETT) during the period September
19 to 26, 1980. The project used a
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Vactor Model 2045 manufactured by
Meyers-Sherman Company, Streator,
Illinois, and operated by the owner,
Axxon Industrial Corporation, Iselin,
New Jersey. Olsen & Hassold, Inc., of
Paterson, New Jersey, supplied a
vacuum truck made by Coleman Envi-
ronmental & Pollution Control Equipment
Co., Inc., East Patchogue, New York.
Twenty-four calm water tests were
performed during a 51/2-day period (13
air conveyor tests and 11 vacuum truck
tests). System performance was evalu-
ated using recovery efficiency (RE) and
oil recovery rate (ORR). These values are
calculated as follows:
Oil volume recovered
oil and water volume recovered
.x100
ORR = °" volume recovered
recovery time
Collection Tank
Oil Suction
Connection
Figure 2. Vacuum truck illustration.
Changes in RE and ORR were found
with varying slick thickness, oil viscosity,
hose length, and blower speed for both
air conveyor and vacuum trucks. Air
conveyors were also evaluated for
various hose distances above the oil
slick.
Conclusions and
Recommendations
The air conveyors proved to recover
oil spills at roughly twice the rate of the
vacuum truck and with three time the
Fine
Paniculate
Filter
efficiency. Air conveyors are also two to
three times as costly as vacuum trucks.
Use of air conveyors is especially
recommended with thin slicks or with
highly viscous products. The vacuum
truck seemed more suited for recovery
at spills with thick slicks or for transport-
ing recovered products from temporary
storage at the spill to a final disposal
site. These conclusions are based on the
results reported. Additional testing will
be required to confirm the results and to
provide additional data to confirm
trends.
Air Flow
Figure 1. Air conveyor operation schematic.
2
Air Conveyor
Air conveyor results show a mean
recovery rate for all tests of 7.2 mVhr of
a 61% oil fluid. No significant perfor-
mance effects were found as a result of
viscosity changes. Low blower speeds
produced the best RE on thin slicks, and
high blower speeds worked best on
thick slicks. Blower speed variations did
not affect ORR values. Increasing slick
thickness increased ORR without affect-
ing RE.
Addition of an outlet in the tanks of air
conveyors to allow for removal of the
free water and oil is recommended.
Many of the trucks observed were
equipped only with valves for removing
liquid above solids that had settled on
the tank bottom. Addition of sight
gauges in the tank would aid operators
in determining the volume of oil and
water in the tank. Development and
testing of skimming heads is needed to
increase the RE of air conveyors further.
These heads will also be needed to
effectively recover oil slicks in waves.
Vacuum System
Mean oil recovery rate for all vacuum
truck tests was 13.3 mVhr of an 18% oil
fluid. Recovery efficiency increased
with blower speed, but no significant
changes were found for various hose
lengths, oil viscosities, or slick thick-
nesses. Oil recovery rate was unaffected
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by blower speed or hose length. ORR
was slightly decreased by increased oil
viscosity, and increasing the slick
thickness. Placing simple, weir-type
skimmers at the end of the inlet hose
doubled the RE without affecting ORR.
Vacuum trucks seem particularly
suited for use with thick slicks and with
skimmers attached to the inlet for
increased RE. Testing with additional
skimmers is recommended to determine
applicability and performance. Addition
of sight gauges to the storage tanks
would aid operators in determining the
volumes of water and oil recovered.
The full report was submitted in
fulfillment of Contract No. 68-03-3056,
Job Order No. 80, by Mason & Hanger-
Silas Mason Co., Inc., under the
sponsorship of the U.S. Environmental
Protection Agency.
DonaldC. Gates and Kevin M. Corradino are with Mason & Hanger-Silas Mason
Co., Inc.. Leonardo, NJ 07737.
Richard A. Griffiths is the EPA Project Officer (see below).
The complete report, entitled "Testing Truck-Mounted Vacuum and Air Conveyor
Systems for Oil Spill Recovery." (Order No. PB 83-114 538; Cost: $8.50,
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
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U.S. GOVERNMENT PRINTING OFFICE: 1982 659-O17/O867
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Environmental Protection
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Information
Cincinnati OH 45268
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