EPA-R2-73-166
APRIL 1973 Environmental Protection Technology Series
Oil/Sorbent Harvesting System
for Use on Vessels of Opportunity
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
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EPA-R2-73-166
April 1973
OIL/SORBENT HARVESTING SYSTEM FOR
USE ON VESSELS OF OPPORTUNITY
By
James D. Sartor
Carl R. Foget
Robert W. Castle
Contract No. 68-01-0069
Project 15080 HER
Project Officer
J. Stephen Dorrler
Edison Water Quality Research Laboratory
Edison, New Jersey 08817
Prepared for
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
For sale by the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. 20402
Price $1.28 domestic postpaid qr^faPO Bookstore
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents neces-
sarily reflect the views and policies of the
Environmental Protection Agency, nor does mention
of trade names or commercial products constitute
endorsement.or recommendation for use.
ii
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ABSTRACT
A system for harvesting mixtures of oil and sorbent materials,
primarily straw, which could be utilized for the recovery of floating
oil from water was developed for use on vessels of opportunity.
A three-phase test program was conducted to evaluate candidate
system components and operating specifications for the oil/sorbent
harvesting system. The first phase of the program involved testing
individual system components and operating parameters as to their
effectiveness in picking up sorbents only. The first phase was con-
ducted under actual conditions in a saltwater slough. The second phase
of the test program entailed evaluating those operating characteristics
of the harvesting system components selected in the first phase using
crude oil and various sorbents in a test tank. The third phase of
the test program entailed the installation of the complete system on
a vessel of opportunity (an LCM), and demonstration of the ability
of the system to operate under actual conditions. The system was
evaluated both in the San Francisco Bay and off Coal Oil Point (Santa
Barbara) where sorbent materials were dispersed over natural oil slicks.
The system utilizes commercially and readily available equipment
which, with minor modifications, was assembled on-site onto available
vessels. The system was found to be very effective in recovering
sorbents (straw and polyurethane foam) from the water surface.
iii
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CONTENTS
Section
I
II
III
IV
V
VI
VII
VIII
IX
X
CONCLUSIONS
RECOMMENDATIONS
INTRODUCTION
SYSTEM DEVELOPMENT
COMPONENT REQUIREMENTS AND AVAILABILITY
INSTALLATION PROCEDURES (LCM)
INSTALLATION PROCEDURES (CONVENTIONAL VESSEL)
OPERATIONAL PROCEDURES
ACKNOWLEDGMENTS
REFERENCES
Page
1
3
5
9
29
49
77
89
97
99
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ILLUSTRATIONS
Figure Page
1 Test Platform 10
2 Test Platform - Deflecting Wings Removed 10
3 Phase I Test Site (Redwood City, Calif.) 11
4 Rubber Belt with Holes 11
5 Rubber Belt with Flights 12
6 Wire Mesh Belt 12
7 Straw on Test Area 13
8 Test Tank Setup for Phase II Testing 17
9 Richmond Inner Harbor Basin 19
10 Richmond Test Site 20
11 Coal Oil Point 20
12 LCM with Conveyor in Front 21
13 LCM with Conveyor in Front (detail) 22
14 LCM with Conveyor on Side 22
15 LCM with Conveyor on Side (detail) 23
16 Spiral Wire Mesh Belt 24
17 Flat Wire Mesh Belt 24
18 Opening Cut in Front of LCM ' 26
19 LCM-3 31
20 LCM-8 31
21 LCVP 32
22 LCU 32
23 Open Hopper Barge 34
24 Deck Barge 34
25 Gulf Coast Work Boat 36
26 Frame Conveyor 38
27 Mobile Frame Conveyor 40
28 Mulch Spreader 43
29 Debris Box 45
vi
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ILLUSTRATIONS (continued)
Figure Page
30 Flat Conveyor Installed on Deck Barge 47
31 Flow Diagram of Installation Aboard an LCM 50
32 Wing Support Structure 51
33 Wing Attachment Plate Detail 52
34 Typical Internal Structures Encountered in Hole Cutting 53
35 Cutting a Hole in the LCM Ramp 54
36 Recommended Conveyor Belt Types 54
37 Increasing Surface Roughness of Drive Pulley 55
38 Installation of Drive Gears 55
39 Installation of Wing Support Structure and
Conveyor Belts 56
^ 40 Critical Installation Angles 57
41 Bracket Attachment of Rear Conveyor Mount 57
42 Wing Support Detail 59
43 Installation of Wings 60
44 Finished Installation Showing Supporting Struts 60
45 Sorbent Guide Installation 62
46 Installation of Sorbent Guides 63
47 Splash Shield, Gate Removed 63
48 Splash Shield, Conveyor Installed Through Hole
Cut in Gate 63
49 Bull Nose (schematic) 65
50 Installation of Bull Nose 66
51 Bull Nose Flashings 66
52 Additional Bull Nose Flashings 67
53 Installation of Debris Box 68
54 Installation of High Capacity Bilge Pumps 69
55 Typical Strawblower Installation on Bow of
Modified LCM 70
VII
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ILLUSTRATIONS (continued)
Figure Page
56 Installation of Conveyor Assembly, Gate Removed 71
57 Installation of Foward Conveyor Mounts 72
58 Splash Shield Installation with Gate Removed 73
59 Positioning Side-Mounted System on LCM 74
60 Rear Conveyor Mount and Supplementary Brace 75
61 Forward Waterline Attachment of Assembly 75
62 Chute Detail 76
63 Finished Installation Showing Supplementary Braces 76
64 Positioning Side-Mounted System 81
65 Vessel Requirements for Various Oil Spill Sites and
Cleanup Times 91
66 Number of Mulchers Required for Different Cleanup Times 92
viii
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TABLES
Page
1 Test Results - Phase I, Wing Deflector Angle and Depth 14
2 Test Results - Phase I, Conveyor Vertical Angle and
Depth in Water 14
3 Test Results - Phase I, Evaluation of Conveyor Belts 15
4 Test Results - Phase II 18
5 Full-Scale Test Results - Phase III, San Francisco Bay 25
6 Test Results - Phase III, Coal Oil Point 27
7 Landing Craft Specifications 33
8 Vessel Survey in West Coast Ports 37
9 Summary of Portable and Frame Conveyor Equipment
Specifications 39
10 Specifications of Wire Mesh Belts 41
11 Large Manufacturers of Wire Mesh Belts 42
12 Power Mulcher Specifications 43
13 Specifications of Containers and Bins 45
14 Operations Required for Installation of Oil/Sorbent
Recovery System on Landing Craft 49
15 Labor and Time Requirements for Installation on LCM 50
16 Operations Required for Installation of Oil/Sorbent
Recovery System on Vessels Other Than Landing Craft 77
17 Labor and Time Requirements for Installation on
Conventional Vessel 78
18 Cost Estimate for Individual Components of Oil/Sorbent
Harvesting System 94
19 Cost Estimate for Various Combinations of Oil/Sorbent
Harvester System 95
ix
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Section I
CONCLUSIONS
The oil/sorbent harvesting system operated and evaluated in this
study proved to be very effective in recovering sorbents (straw and
polyurethane foam) from the water surface. In the test program,
various system components were evaluated, leading to the following
findings.
1. The wire mesh type of conveyor belting was the only
belting material tested which would pick up straw from
the water surface without manual assistance.
2. The depth in the water of the conveyor and deflector
wings should be at least 6 in. to minimize loss of straw
under the wings and conveyor.
3. Forward speed of the vessel and speed of the conveyor
belt did not appreciably affect the pickup capability
of the conveyor belts.
4. The openings in the wire mesh belt did not clog with a
Bellridge crude oil which has an API gravity of 15. The
presence of oil did not affect the system's performance
in recovery of sorbents.
5. The optimum horizontal angle for the deflector wings
is 45 deg. At larger angles, sorbent is lost under
the wings. At smaller angles, the sweeping path is
reduced.
6. The vertical angle between the conveyor belt and the
water line should not exceed 25 deg. At a larger angle,
the straw will not go up the wire mesh belt.
7. If all components of the oil/sorbent harvester system
are readily available, the system can be installed on
board a vessel of opportunity in 9 hours or less.
8. The use of the side-loading conveyor installation allows
the oil/sorbent harvester system to be used on a wide
assortment of vessels- of opportunity.
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9. In the three West Coast ports that were surveyed, suf-
ficient suitable vessels of opportunity were located on
which the oil/sorbent harvester could be installed to
handle a major oil spill.
10. The oil/sorbent harvester system was easily able to pick
up sorbents under different sea conditions ranging from
the quiescent state of a protected harbor to open ocean
conditions with 2- to 3-ft swells.
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Section II
RECOMMENDATIONS
On the basis of the findings of this study, the following recommenda-
tions are offered.
1. It is recommended that oil companies and oil spill
consortiums implement the oil/sorbent harvester system
through the purchase of the necessary wire belt materials
and through contingency contracts with local suppliers of
the various components.
2. It is recommended that further research be conducted on
the oil sorbing ratios of various sorbents under actual
open water conditions and on the dispersal rates of
sorbents under actual open water conditions.
3. It is recommended that the oil/sorbent harvesting system
described in this report be evaluated on other types of
vessels of opportunity.
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Section III
INTRODUCTION
BACKGROUND
An increasing hazard of contamination of the environment with oil has
accompanied the worldwide growth of the petroleum industry, a growth
that has occurred in response to steadily increasing energy demands of
the more advanced societies of the world. A recent tentative conclusion
by a Massachusetts Institute of Technology-sponsored study group states:
"it is likely that up to 1.5 million tons of oil
are introduced into the oceans every year through
ocean shipping, offshore drilling, and accidents.
In addition, as much as two or three times this
amount could eventually be introduced into water-
ways and eventually the oceans, as a result of
emissions and wasteful practices on land."
The environmental impact of a major oil spill was most dramatically
demonstrated by the Torrey Canyon disaster in 1967 which is reported
to have cost the British Government $8 million in cleanup costs alone.
In another incident, the Santa Barbara Platform A release in 1969 re-
sulted in a research and development program directed towards development
of oil spill recovery techniques.
A considerable amount of effort has been expended on the development
of methods for the direct recovery of oil from the water surface; two
basic approaches have been used:
• Skimming the oil directly using specially designed
pickup heads, weirs, pump systems, and oil/water
separator equipment
• Removal with the aid of sorbent materials.
Direct oil skimming requires no materials to be added to the oil slick;
however, this technique usually fails when wave height approaches 2 ft
and current velocity is in the 2-3 knot range. Under these conditions,
the water to oil ratio becomes so large that the volume of oil recovered
is insignificant.
Sorbents, however, are not affected to such a degree by adverse weather
and sea conditions. In fact, the sorption process is enhanced when sub-
jected to mixing. When applied early in an oil spill incident, sorbents
reduce the spread of the slick and the oil/sorbent mixture is easier to
contain.
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A compendium on oil spill treating agents by the Battelle Memorial
Institute lists some twenty-six sorbent materials available for use
on oil spills. For each sorbent, the compendium gives the chemical and
physical properties, cost, application rate, availablity and spill
experience. The Dillingham Corporation has compiled a comparative
description of the most promising of the sorbents currently available.
Straw is considered to be one of the best of the sorbents currently
available. It is inexpensive, generally available and relatively easy
to apply. Laboratory test have shown that straw will absorb over five
times its weight of oil at air and water temperatures as low as 40 to
45 F. Straw has been used on several oil spills as a sorbent, including
the Santa Barbara incident where some 100 tons/day of straw was utilized
on both water and beach areas.
The principal problems in the use of sorbents are:
• Uniform dispersal
• Adequate contact with oil
• Recovery methods.
Wind is a major factor in distributing sorbents because of their low
density.
Recovery of sorbents on a large scale in open water has never been
attempted. At Santa Barbara, straw was dispersed onto oil near the
surf line and allowed to wash ashore with the incoming tide. URS
Research Company, in a study directed towards the evaluation of beach
restoration methods, developed procedures for removing oil-soaked straw
from beach areas. In the harbor area at Santa Barbara, straw was re-
covered from the water by personnel operating out of small "duck" boats,
each containing a 55 gal. drum. The oil-soaked straw was lifted out of
the water with rakes and placed into the drums. This manual procedure
has been widely used in harbors by commercial oil-spill cleanup contrac-
tors.
The necessity of developing techniques for the rapid and effective
removal of oil spills to prevent the contamination of large water and
coastal areas has been recognized. In 1971, the Environmental
Protection Agency issued five research contracts to develop efficient
systems for the removal of floating oil with the aid of sorbent materials,
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OBJECTIVES
The objectives of this study were to design, develop, and proof-test a
system for the harvesting of mixtures of oil and sorbent materials which
are used to aid in the recovery of floating oil frem water.
Specifically, the study was to develop a system for mechanical harvest-
ing of oil/straw mixtures utilizing vessels of opportunity. In addition,
the system was evaluated for the harvesting of oil/polyurethane foam
mixtures and oil/rice hull mixtures.
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Section IV
SYSTEM DEVELOPMENT
A three-phase test program was designed to evaluate candidate
system components and operating specifications for the oil/sorbent
harvesting system. The first phase of the program involved testing
individual system components and operating parameters as to their
effectiveness in picking up sorbents only. A specially built test
platform was utilized with all Phase I tests performed under actual
conditions (i.e., a saltwater slough - or channel - in the southern
portion of San Francisco Bay). The second phase of the test program
entailed evaluating those operating characteristics of the harvesting
system components selected in the first phase using crude oil and
various sorbents. These tests were conducted in the wave tank
facilities at the URS Research Company laboratory. The third and
final phase of the test program involved demonstrating the full-scale
harvesting system installed on board a vessel of opportunity as it
would be used in the event of an oil spill incident. This phase was
performed at two different locations. The first series of tests was
conducted in the Richmond (California) harbor and in San Francisco
Bay using sorbents only (straw and polyurethane foam). The second
series of full-scale tests was conducted in the Pacific Ocean off
the coast of Santa Barbara where oil seeps from the ocean bottom
provide natural oil slicks extending over several square miles.
PHASE I TESTS
The principal objective of the Phase I test was to determine the com-
ponents and operating parameters that would be best suited for incor-
poration into the oil/sorbent harvester system. To enable testing under
real-world conditions with the inherent problems of wind, current and
sea state normally encountered, a special floating test platform was
constructed. The platform (shown in Figs. 1 and 2) was designed to
allow the various operating parameters of the harvesting system to be
easily varied. A 16 ft long frame conveyor (16 in. wide) was installed
on the test platform in a manner which allowed variation of the con-
veyor's depth in the water and its angle of inclination. Deflector
wings were installed on the front of the test platform in a mode that
allowed the horizontal angle and the depth in the water to be adjusted.
A test site was selected in San Francisco Bay (Steinberger Slough, Fig. 3)
near Redwood City which provided somewhat protected water but still
presented the wind and current problems that are normally encountered
on open water.
9
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Fig. 1. Test Platform
Fig. 2. Test Platform - Deflecting Wings Removed
10
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\
rl-
Fig. 3. Phase I Test Site
(Redwood City, Calif.)
Conveyor Belts
The effectiveness of four differ-
ent types of conveyor belts was
evaluated for removing straw from
the water surface. The belts
tested included:
• Smooth rubber belt
• Smooth rubber belt, with
punched holes, approximately
7 percent openings (Fig. 4)
• Rubber belt with 2 in. high
flights every 1 ft (Fig. 5)
• Wire mesh belt, equalized
spiral wound, 3/8 in. mesh
(Fig. 6).
Fig. 4. Rubber Belt with Holes
11
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Fig. 5. Rubber Belt with Flights
Fig. 6. Wire Mesh Belt
12
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Operational Parameters
The various operational parameters of the pickup vessel, the conveyor
system, and the deflecting wings evaluated are listed below:
1. Pickup vessel: forward speed
2. Conveyor system: angle of inclination, speed of belt,
and depth of conveyor in the water
3. Deflecting wings: horizontal angle, and depth in the water.
These parameters were varied during the series of tests to determine
the pickup efficiency of the oil/sorbent harvesting system.
Test Procedure
A known amount of pre-wetted straw was hand-dispersed in a 2 to 3 ft
wide path approximately 50 ft long (Fig. 7). The test platform then
was passed through the straw covered area; the time of the pass and the
amount of sorbent recovered were recorded.
Fig. 7. Straw on Test Area
Test Results and Findings
The results of the Phase I test program are given in Tables 1
through 3.
13
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Table I
TEST RESULTS - PHASE I
WING DEFLECTOR ANGLE AND DEPTH
TEST
NO,
A-l
A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-ll
Note:
TEST
NO.
B-l
B-2
B-3
B-4
B-5
B-6
B-7
B-8
B-9
B-10
B-ll
B-12
HORIZONTAL DEPTH OF DEFLECTOR FORWARD SPEED
ANGLE IN WATER OF VESSEL
(°) (in.) (knots)
65 4 1.5
65 6 1.5
65 6 3.0
65 12 1.5
65 12 3.0
60 8 3.0
60 12 3.0
55 4 3.0
55 8 3.0
45 6 1.3
45 12 3.0
All teati were run with 3/8 In. wire main belt.
Table 2
TEST RESULTS -
CONVEYOR VERTICAL ANGLE
STRAW STRAW
DISPERSED RECOVERED COMMENTS
(Ib wet) (Ib
3.0 0
2.0 0
2.0 0
2.5 0
2.0 0
3.0 0
3.0 0
2.5 1
2.0 1
3.0 2
3.0 2
PHASE I
AND DEPTH
VERTICAL ANCLE OF DEPTH OF CONVEYOR FORWARD SPEED STRAW
CONVEYOR TO WATER TIP UNDER WATER OF VESSEL
(°) , (In.) (knots)
16 2 1.5
16 4 3.0
16 6 2.0
16 8 4.0
20 4 3.0
20 6 3.0
20 8 3.0
25 6 2.0
25 8 4.0
27 6 2.0
27 8 2.0
27 10 4.0
DISPERSED
(Ib wet)
2.5
3.0
3.2
3.0
2.7
3.0
2.5
3.5
2.5
3.0
3.5
4.0
wet)
.25
.5
.4
5 _ Straw want around
and under deflector
_4 wings.
.6
.5
.5 ~| Some straw lost
L around and under
.7 1 wings.
.8 - Picked up almost all
straw.
.9 - No loss around edges.
IN WATER
STRAW
PICKED UP COMMENTS
(lb wet)
1.5 1
j- Some straw lost
2.4 J under belt.
3.0
3.9
_ . Some straw lost
' ~ under belt.
2.8
2.2
3.1
Some straw did not
2_0 go up belt.
0.3
Host of the straw
°-2 ' would not go up
belt at this angle.
0.2 J
Note: All tests ware run with 3/8 in. mesh wire conveyor belt with deflector wings at 45° angle and 6 in.
denth in water.
14
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Table 3
TEST RESULTS - PHASE I
EVALUATION OF CONVEYOR BELTS
TEST
NO.
ANGLE OF
CONVEYOR
<°>
DEPTH OF
CONVEYOR
TIP UNDER
WATER
(in.)
FORWARD
SPEED
VESSEL
(knots)
SPEED OF
CONVEYOR
BELT
(It/min)
AMOUNT
STRAW
DISPERSED
(lb)
Smooth Rubber
C-l
C-2
C-3
C-4
D-l
D-2
D-3
D-4
20
20
18
18
21.5
15
20
21.5
8
6
8
6
8
4
8
8
2
2
2.5
2.5
3
2.5
2.5
2.3
190
250
190
250
Smooth
190
330
190
330
20
20.5
20
21
Rubber Belt
21.5
19.5
21
21
AMOUNT
STRAW
PICKED UP
(lb)
Belt
0
8.5
0
9.0
with Boles
0
5.5
10.4
12.8
STRAW
RECOVERED
(Ib/hr)
0
660
0
841
0
330
772
1,248
COMMENTS
Straw would not go up belt.
Recovery rate with straw
manually forced onto belt.
Straw would not go up belt.
Recovery rate with straw
manually forced onto belt.
Straw would not go up belt.
Some straw lost under con-
veyor tip. Straw manually
forced onto belt.
Rubber Belt with 2 In. nights
E-l
E-2
E-3
F-l
F-2
F-3
F-4
F-5
F-6
17
17
16
22
22
22
20
18
18
2
6
6
2
4
6
6
6
8
1.5
3.0
3.2
2.7
3.5
3
1.5
3.0
4.5
240
280
140
3/8
220
220
220
220
220
220
15
15
22
0
1.5
1.5
0
30
40
Straw would not load onto
belt.
The flights on the belt
caused a great deal of
turbulence at the waters
interface forcing straw
under belt.
in. Wire Mesh Belt
24
19
20
22
18
23
10
9.5
15.2
19
15.2
20.3
590
1,114
1,710
1,628
1,824
1,620
Some straw lost under belt.
Some straw lost under belt.
The major findings of the test program are given below.
1. The wire mesh belt proved to be the most effective. The
smooth rubber belt and the rubber belt with holes in it
would only pick up straw with manual assistance (i.e.,
rake or fork straw onto the belt surface). Flighted belts
are generally not applicable because of the turbulence
created at the water interface.
2. The forward speed of the test platform (1.5 to 4.5 knots)
did not appreciably affect the pickup capability of the
wire belt system.
3. Varying the conveyor angle to the water resulted in the
determination of a maximum practical value of around 25 deg,
Above this angle, pickup efficiency rapidly decreases.
4. Varying the conveyor belt speed (between 200 and 500 fpm )
did not materially affect pickup capability of the wire
mesh belts. However, higher speeds (e.g., 400 fpm) in-
crease the belt's capacity to move large volumes of straw.
5. The depth of the conveyor in the water is an important
parameter. The tip of the conveyor should be at least
6 in. under the water level to minimize turbulence at the
15
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water interface, to keep straw from going under the belt,
and to keep the belt in the water during rough conditions.
The horizontal angle between the conveyor and the deflector
wings should be less than 55 deg. At angles greater than
55 deg, the straw tended to go under the wings. A 45 deg
angle was found to be very satisfactory. Smaller angles
decrease the harvesting path.
The depth of the deflector wings in the water should be
at least 6 in. to prevent straw from going under the
wings and to keep the wings under water -in rough con-
ditions. Greater depths increase the drag resistance of
the wings and slow the vessel.
PHASE II TESTS
The objective of the Phase II tests was to evaluate the performance of
the wire mesh conveyor system with oil-soaked sorbents. The tests
were performed in a test tank located in the URS Research Laboratory
in San Carlos, California. The conveyor system with the wire mesh belt
was installed in the test tank (36 ft x 4 ft x 4 ft) in such a manner
as to allow the conveyor's vertical angle and depth in the water to be
varied. Figure 8 shows the conveyor in position. An 18 hp outboard
motor was installed at one end of the test tank approximately 6 ft from
the end of the conveyor. The motor, when operating, provided a current
of up to 2 knots in the tank and directed the oil-soaked sorbents onto
the conveyor belt.
Test Parameters
Two series of tests were performed. The first test se.ries was to re-
evaluate the various operating parameters previously evaluated in Phase I,
utilizing straw only. The second test series evaluated the performance of
the system utilizing crude oil and three types of sorbent: straw, rice hulls,
and polyurethane foam.
Test Procedure
Two small booms were placed across the test tank, one directly behind
the motor and the other, a removable boom, right in front of the conveyor.
A known amount of San Joaquin crude oil (API gravity of 15.9 at 60 F)
was poured into the boomed area. Then a known amount of sorbent was
dispersed manually onto the oil and allowed to soak for a 5-minute period.
The outboard motor (current generator) and conveyor system were started
and the boom in front of the conveyor was removed, allowing the oil-
soaked sorbent to move onto the conveyor belt. The sorbent was collected,
allowed to drain of water for 1 hr, and then weighed.
16
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8' - 0'
Figure 8. Test Tank Setup for Phase II Testing
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Test Results and Findings
The results of the tests are given in Table 4. Phase II test findings
during the conveyor system performance included:
1. Confirmation of the open water Phase I tests: that the
depth of the conveyor in the water should be at least
6 in. to minimize loss of straw under the belt.
2. The heavy crude oil and oil-soaked sorbents did not
clog the openings in the wire mesh belt. The wire
belt initially picked up a thin coating of oil, but no
further oil buildup was observed through the remainder of
the tests.
3. The wire mesh belt effectively picked up oil-soaked rice
hulls and oil-soaked 2-in. square pieces of polyurethane
foam. Although the rice hulls were smaller than the 3/8 in.
mesh openings of the wire belt, the oil/hull mixture ag-
glomerates were easily picked up.
Table 4
TEST RESULTS - PHASE II
TEST
NO.
WT-1
WT-2
WT-3
WT-4
WT-5
WT-6
0-1-1
0-1-2
0-1-3
0-1-4
0-1-5
#*
0-3
ANGLE
OF QUANTITY
BELT SORBENT OF OIL
(°) (gal.)
23
23
23
16
17
20
20
20
20
20
20
20
20
Straw
Straw
Straw
Straw
Straw
Straw
Straw
Straw
Straw
Straw
Straw
Rice Hulls
Foam 2" Squares
0
0
0
0
0
0
8
8
8
4
4
2
2
CURRENT
SPEED
(knots)
1
1.5
2
1.5
2
1.5
1.6
1.6
1.6
1.6
1.6
1
1
CONVEYOR
DEPTH
TIP
(in.)
3
6
6
i
2
8
8
8
8
8
8
8
8
TIME
REQUIRED
(min)
2:20
1:07
1:07
0:49
1:30
0:53
0:53
0:57
0:52
1:17
15:00
—
MATERIAL
DISPERSED
PRE-SOAKED
(lb)
80
78
77
35
70
52
20
50*
60*
67*
400*
3
1
.MATERIAL
PICKED UP
DRAINED
(lb)
78
77
70
20
52
48
50
60
67
74
--
LBS/HR
(wet)
2,008
4,137
3,761
1,469
2,080
3,260
3,396
3,789
4,638
3,460
Note: Constant belt speed of 240 ft/min in all tests.
* Straw + oil weight.
** These two tests were qualitative only and were run just to determine if the system
could recover these sorbent materials, which it did.
PHASE III TESTS
The principal objective of the Phase III tests was to evaluate the per-
formance of the full-scale harvesting system installed aboard a vessel of
opportunity under actual open water conditions using oil and sorbents.
18
-------
The test program was initially designed to be wholly performed in the
Richmond Inner Harbo'r and on San Francisco Bay near Angel Island. How-
ever,, failure to receive the necessary permission from the local regula-
tory agencies to spill oil forced a change in plans with the subsequent
result that two full-scale test series were performed. The first, using
sorbents only, was carried out in the original test site location (Figs.
9 and 10). The second series of tests were performed off Coal Oil Point,
10 miles north of Santa Barbara (Fig. 11), where natural oil seeps result
in oil slicks which were utilized as the oil source onto which sorbents
were dispersed and then picked up.
MURPHY
f£T£R kiiv/rr AHD sow
MM/ME
Fig. 9. Richmond Inner Harbor Basin
19
-------
-
Fig. 10. Richmond Test Site
?^Tr
i*
Fig. 11. Coal Oil Point
20
-------
Test Series No. 1
For this test series two different conveyor mounting configurations
were tested. The first mounting configuration involved removing the
gate or ramp from the front of an LCM landing craft and installing
two wire mesh belt conveyors with deflector wings off the front of
the vessel (Figs. 12 and 13). The second type of mounting config-
uration required installing a single wire mesh belt with one deflector
wing on the starboard side of the LCM (Figs. 14 and 15). In this
configuration, the hull of the LCM acts as the other deflector wing.
The side-mounted conveyor system is applicable to a wide variety of
vessels with low freeboards (i.e., barges, work boats, etc.)
Fig. 12. LCM with Conveyor in Front
21
-------
Fig. 13. LCM with Conveyor in Front (detail)
Fig. 14. LCM with Conveyor on Side
22
-------
Fig. 15. LCM with Conveyor on Side (detail)
Operational Parameters
Tests were performed under two water conditions: (1) the relatively
quiescent waters of the Richmond inner harbor which is representatave
of protected waters, and (2) the choppy waters of central San Francisco
Bay («2 ft swells with some whitecaps) which is typical of open
harbors. Straw and polyurethane foam were evaluated as sorbents.
Two 26 ft x 16 in. wide Clearfield frame conveyors were rented and
each equipped with different wire mesh belts. One wire mesh belt
(Fig. 16) was a 1/2 in. mesh spiral equal wound which was friction
driven by the conveyor head pulley. The other wire belt was a
1/2 in. x 1/2 in. flat wire belt (Fig. 17), gear driven by toothed
sprockets which were added to the conveyor drive assembly.
23
-------
rx/' '/ i'f.''/'ft'-'I'l'j'j'i',;'.'/'/"/
r.v,- -.-..- •Vi-ViV.v.i v,r ,wv
'«"/ 'if':•''.'/.'>'/.'i.'i.•/.•/.•/•.•<•!•»•/•/•-
Fig. 16. Spiral Wire Mesh Belt
wrr==> --
-:-—-T======isr.i •
_^_i=.=_.. ..
^w.v_-_-_~—.--_-_-_-_- - > .Jfj^s
^-^-E^E^E"-^^-^-"- .,
2""Z^I—^•3»ZZZ-—-""-- - •
Fig. 17. Flat Wire Mesh Belt
-------
Test Results and Findings
Results for the full-scale tests are given in Table 5. Observations
of the oil/sorbent harvester performance are given below.
• Under all conditions tested, both mounting configurations
picked up more than 90 percent of the straw and polyurethane
foam that was dispersed (the remainder being too widely
scattered by wind and current to recover).
• A completely quantitative analysis of straw dispersed
versus straw picked up was impossible. As Table 5 shows,
the straw picked up retained over four times its initial
dry weight of water even after 1 hr draining time.
• An estimated 80 to 90 percent of the sorbent was recovered
on the first two passes of the harvesting system.
• A recurring problem with the side-mounted conveyor con-
figuration was that straw passing under the hull on the
side that had no conveyor would plug up the cooling water
intake of the port engine, necessitating the engine
being shut down. This occurred after 15 to 20 minutes
of operation. This problem did not occur with the front-
mounted installation. A possible solution would be to install
deflector plates in front of the cooling water intakes on
the bottom of the hull. (Newer model LCMs and many con-
verted older models are equipped with closed cooling systems,
eliminating this problem.)
Table 5
FULL-SCALE TEST RESULTS - PHASE III
San Francisco Bay
WT STRAW TIME 1ST PERCENT TIME 2ND PERCENT WT STRAW
TEST SEA DISPERSED PASS STRAW PASS STRAW PICKED IP
NO. DATE STATE LOCATION DRY (Ib) (mln) RECOVERED (mlo) RECOVERED WET (Ib)
1
2
3
4
5
6
7
Front-Mounting Cocf iguration
4/3/72 2 S.F. Bey 85 2 ~ 2j
1/4/72 0-1 Richmond 480 3j 50 1
Inner
Harbor
4/4/72 1 Richmond 25 cu ft 2j 85
Inner polyure-
Karbor thane foam
V5'72 1-2 Richmond 540 3 45 3j
Inner
Harbor
4/6/72 1 Richmond 15 cu ft 2-3 90
Inner foam
Harbor
Side-Mounted Configuration
4/6/72 1 Richmond 300 2 55 1}
Inner
Harbor
4/7/72 1-2 S.F. Bay 180 2 85 —
Preliminary
test to check
current and
wind
40 1 , 850
45 2,100
40 1,200 Engine cooling;
filters plug-
ged up with
straw after
650 1/2 hour
Note: In all tests: vessel speed = 2 kt.
conveyor: angle = 20 deg; speed = 350 fpm; depth of conveyor tip = 6 in.
25
-------
Test Series No. 2
A second series of full-scale tests was performed off Coal Oil Point,
10 miles north of Santa Barbara (Fig. 11). This area not only pro-
vided natural oil slicks but also allowed the oil/sorbent harvesting
system to be tested in open sea conditions. The test procedure and test
equipment were essentially the same as used in the San Francisco Bay
test series. The front-loading dual conveyor mounting configuration
was used with one major difference. Instead of removing the front gate
or ramp of the LCM, an opening 6 ft long by 2 ft high was cut in the
gate and the conveyors installed through the opening (Fig. 18). This
installation mode provided better watertight integrity for the LCM.
The entire oil/sorbent harvesting system was installed on board the
LCM in one 9-hour working day.
Fig. 18. Opening Cut in Front of LCM
Test Results and Findings
Table 6 gives the results of the Santa Barbara tests.
of the system's performance are listed below.
Observations
The oil/sorbent harvesting system was able to pick up an
estimated 90 percent of sorbents dispersed under open sea
conditions (ocean swells were 3 to 4 ft high).
The LCM with the oil/sorbent system attached was able to
travel at a speed of 5 knots in open sea conditions
without damaging the deflecting wing supports or shipping
any water into the vessel.
26
-------
The oil/sorbent conveyor system easily picked up numerous
"oil patties" which were present in the natural oil slicks.
Table 6
TEST RESULTS - PHASE III
Coal Oil Point
TEST
NO.
SB-1
SB- 2
SB-3
PICKUP SPEED
(knot)
2
3
3
SORBENT
DISPERSED
300 Ib straw
500 Ib straw
20 cu ft of foam
ESTIMATED
VOLUME OF
OIL ON WATER
2,000 gal. 'sq ;ni
500 gal./sq mi
500 gal. - sq mi
TIM OF
FIRST PASS
(min)
2
2
U
ESTIMATED
PERCENT
SORBENT
RECOVERED
55
50
65
TIME OF
SECOND PASS
(rain)
3
2j
2
ESTIMATED
PERCENT
SORBENT
RECOVERED
40
40
30
27
-------
Section V
COMPONENT REQUIREMENTS AND AVAILABILITY
As a result of the system development program described in the previous
section, a survey of component availability and specifications was
conducted. The oil/sorbent harvesting system designed and evaluated in
this study has four major components: the vessel of opportunity, the
conveyors and belts, the sorbent distributor; and sorbent storage and
handling equipment. All of the major system components are "off the
shelf" items that can be assembled in one day to form the oil/sorbent
harvesting system. A discussion of the general requirements, specif-
ications, and availability of the system components follows.
VESSEL TYPES
It is impossible to define a particular type of vessel as optimum for
the oil/sorbent harvester system because of the diversity of types
found both locally and regionally and because of the varying conditions
under which the vessels would be required to operate. Generally;
there are a number of requirements which must be met for conveyor
installation, including:
• Low freeboard or main deck level
• Draft commensurate with working water depth
• High degree of maneuverability
• Large capacity
• Clear deck space amidships and aft (preferably
forward also)
• Preferably metal hulled (for easy attachment
of the system)
A survey of vessels indicated a number of types that would be suitable
for the oil/sorbent harvesting system, as listed below.
• Converted surplus landing craft - LCMs, LCVPs, LCUs
• Gulf Coast work boats
• Deck and hopper barges
29
-------
Surplus Landing Craft
The LCM (Landing Craft Mechanized, Figs. 19 and 20) is a surplus naval
vessel commonly used by marine salvage and construction organizations
as a work boat. It is a diesel-powered, twin-screw, shallow-draft
vessel with a high degree of maneuverability. The well deck allows
sufficient room for installation of the dual conveyor system and a
storage container for the harvested oil/sorbent mixture. Many com-
mercial LCMs have had the landing ramp welded shut; however. this does
not affect their suitability as a recovery vessel as an opening can
be cut in the ramp for the conveyors or a side-mounted configuration
may be used .
The LCVP (Landing Craft Vehicles and Personnel, Fig. 21) is a diesel-
powered, single-screw shallow-draft vessel used commercially as a small
work boat or a water taxi. Because it is a single-screw vessel it is
not as maneuverable as an LCM. A single conveyor system can be installed
on the front of the LCVP; however, due to its small size (36-ft length)
it would have a very limited capacity for oil-soaked sorbent and would
have to be unloaded frequently-
The LCU (Landing Craft Utility, Fig. 22) is a diesel-powered, triple-
screw, shallow-draft, highly maneuverable ship originally designed to
land tanks and artillery on beaches. The LCU has a well deck 76 ft
long by 31 ft wide which could conveniently accommodate 8 to 10 large
storage containers. A dual conveyor system could be easily mounted on
the front of the vessel and chutes or side-loading conveyors utilized
to shift the collected sorbents to the various storage containers.
LCUs are not as commonly available as the smaller LCMs. They are found
more frequently in remote areas where they are used to transport equip-
ment and vehicles to beach areas.
Specifications of the various types of landing craft are presented in
Table 7.
30
-------
Fig. 19. LCM-3
Fig. 20. LCM-8
31
-------
Fig. 21. LCVP
Fig. 22. LCU
32
-------
Table 7
LANDING CRAFT SPECIFICATIONS
VESSEL
TYPE
LCM-3
LCM-6
LCM-8
LSU #1466
LCU #1608
LCU #1610 & 1626
LCVP
LENGTH
(ft)
50
56
74
115
115
135
36
SIZE OF
BEAM DRAFT HOLD (ft) SPEED
(ft) (ft) (L v w x H) (knots)
14 4 31 x 9 x 6 9.5
14 4 37 x 11 x 6 9
21 5 45 x IS x 4 9
34 5 76 x 31 x 6 8
34 4 76 x 31 x 6 8
29 4.5 u.a. 11
10 3.5 18x6x5 9
CAPACITY
' (tons) CREW
30
34
60
167
183
168
4
2
2
2
4-5
4-5
4-5
1
ENDURANCE
OR RANGE
(mi)
130
130
190
1200
1200
n.a.
110
ii.a. = not available.
Barges
Barges are by far the most readily available type of vessel on which to
install the sorbent harvester system. Two types are suitable for the
system: hopper barges and deck barges.
The open hopper barge is basically a simple double-skinned, open-top
box, the inner shell forming a long hopper or cargo hold. They are
generally of welded plate construction, usually with double bottoms for
greater safety (Fig. 23). There are three popular sizes:
• 1000-ton capacity, 175 ft long by 26 ft wide,
9-ft draft
• 1500-ton capacity, 145 ft long by 35 ft wide,
9-ft draft
• 3000-ton capacity, 290 ft long by 50 ft wide,
9-ft draft
The deck barge is a simple box hull, generally with a heavy-plated,
well-supported deck (Fig. 24). A great number of these vessels are
used by the construction industry as work platforms and for moving
and storing equipment and supplies. Generally deck barges range in
capacity from 350 tons to more than 1500 tons, the most common sizes
being:
• 100 ft long by 26 ft wide
• 130 ft long by 30 ft wide
• 195 ft long by 35 ft wide.
33
-------
Fig. 23. Open Hopper Barge
Fig. 24. Deck 3arge
34
-------
Hopper and deck barges could be used either as support vessels or as
the primary pickup vessel. Conveyors could be installed in the side-
mounting configuration and would be capable of picking up and storing
oil-soaked sorbents. The major advantages of the barges are:
• The wide beam acts as a directing boom as, well as
allowing the use of several recovery devices on
one hull
• Hulls and deck are usually metal, allowing easy attach-
ment of the conveyors by welding
• Decks are clear and large, allowing utilization of a
wide variety of support equipment
• Freeboard is adjustable by adding or pumping ballast
water. This is very significant in that it allows
maintenance of the proper depth of the recovery
equipment despite the loading of the vessel
• The large capacity permits the use of fewer systems
in the event of a large incident
• The barges are readily available .
The major disadvantages are:
• Poor maneuverability; a tugboat would be required
for propulsion
• Poor visibility of the pickup area from the pusher
tugboat
• Slower transit speeds.
Gulf Coast-type Work Barges
This type of vessel is typically a diesel-powered, single-hull, twin-
screw configuration with a large open deck area aft (Fig. 25). These
vessels are quite variable in size; however, deck configurations are
very similar- The low freeboard work area would provide sufficient room
for side-mounted conveyor installations and moderate to large sorbent
storage capacity. These vessels have typically shallow drafts, high
speed, moderate to long range, and navigation equipment. The availa-
bility of the Gulf Coast-type work boat is closely related to offshore
oil activity. If offshore wells are being drilled in an area there
will be many vessels of this type available.
35
-------
Fig. 25. Gulf Coast Work Boat
VESSEL SURVEY
A brief vessel survey was performed in three West Coast ports to check
on the availability of the proper type of "vessels of opportunity" on
which to mount the oil/sorbent harvester system. The three ports in
which the survey was conducted were San Francisco/Oakland, Long Beach/
Los Angeles and San Diego, California. The survey procedure was simply
to rent a small boat with outboard motor and cruise the entire water-
front area of each port. LCMs, LCVPs, LCUs, Gulf Coast work boats and
deck barges (considered the prime candidates for the oil/sorbent har-
vester system) were the types of vessels included in the survey. In
all three ports deck and hopper barges were so numerous that an exact
count would have been superfluous. The number of vessels counted in
the three ports should be considered conservative (i.e., the minimum
number of vessels that would be available), since by the very nature of
the survey (a one-day vessel count) many other suitable vessels that
normally homeport in the three ports could have been out working and
would not show up in the count.
The U.S. Navy has large facilities in all three of the ports visited and
many Navy LCMs, LCUs and LCVPs were seen; however, all U.S. government
vessels were specifically excluded from the vessel survey. Results of
the vessel survey shown in Table 8 indicate that in all ports surveyed a
sufficient number of vessels were found to handle a large oil spill.
36
-------
Table 8
VESSEL SURVEY IN WEST COAST PORTS
PORT
San Francisco
Bay
Long Beach
San Diego
VESSEL
LCM- Gulf Coast " Deck
3 or 6 LCM-8 LCU Work Boat LCVP Barges
.10 2 Numerous
7 4* 4 4 Numerous
351 1 1 Numerous
* Two of the LCUs were severely modified - no propulsion
OTHER TYPES OF VESSELS
In addition to the aforementioned types of vessels, occasionally other
suitable craft may be locally available, such as:
• Naval seaplane wreckers (YSDs or MaryAnns)
• Self-powered barges
• Some tug and tow boats with large open decks
• Some small coastal lighters
• Miscellaneous special purpose craft.
Essentially, any craft meeting the requirements listed in the beginning
of this section may be adapted. Modifications to these variable types
are expected to be the same as outlined for the primary vessels, with
minor variations.
SUPPORT VESSELS
Support vessels will depend on spill characteristics such as spill size,
weather conditions, etc. These vessels will consist of supervisory
craft, boom tenders, and supply craft, and may range in design from
pleasure yachts to supply and tug boats. Where direct land discharge
of oil/sorbent picked up by the harvesting vessels is not practical,
additional storage vessels such as deck barges equipped with cranes
would be required. Such vessels should be strategically positioned
with regard to initial slick location and predicted oil spill movement.
These large deck barges could act both as storage vessels for recovered
sorbent and as storage vessels for fresh sorbents.
37
-------
CONVEYOR SYSTEM REQUIREMENTS
A survey of selected conveyor manufacturers was made and literature col-
lected in order to determine the various types of conveyors that are
commonly available and could be considered candidates for the oil/sorbent
harvester system. Based on this survey, specific conveyor requirements
were defined and are listed below:
• Portable or mobile conveyor
• Driving motor on discharge end or center of conveyor
• Conveyor length between 10 and 60 ft
• Loading (or lower) end of conveyor free of hydraulic
connections.
The light frame conveyor (Fig. 26) was found to be ideally suited for
the oil/sorbent harvester system as it met all of the above requirements.
Fig. 26. Frame Conveyor
-------
Furthermore, a check of construction equipment rental yards in the San
Francisco Bay area found that the frame conveyor in 16-ft and 26-ft
lengths was the most readily available for rent of any type of portable
conveyor (the largest rental agency in the area has 60 of them in his
inventory). The mobile or portable conveyor was the other type found
to be suitable for incorporation into the oil/sorben't harvesting system.
This type of conveyor is essentially a frame conveyor mounted on an
undercarriage with wheels (Fig. 27) allowing the conveyor angle and
height to be adjusted. The availability of this type of conveyor is
not as great as the frame conveyor; however, most rental yards contacted
had several in stock. For LCM application, the undercarriage and wheels
of the portable conveyor could be retained with the whole assembly
affixed by turnbuckles or cables. For any side-mounted configuration,
it would be best to remove the undercarriage before installing the con-
veyors. Specifications of various conveyors found suitable for the
oil/sorbent harvester system are given in Table 9.
Table 9
SUMMARY OF PORTABLE AND FRAME
CONVEYOR EQUIPMENT SPECIFICATIONS
COMPANY
AND MODEL
Farquhar-343T
Rapistan
General Duty
Morgan
Morgan EB
Kolberg-200
Rapistan-4121
Pioneer
Black we 11
Creteveyor
Clearfield
C&H Series
Clearfield
D-2,3
LENGTH OF WIDTH OF
CONVEYOR CONVEYOR BELT SPEED
(ft) (in.) (fpm)
20 -
10
40
24 -
30
15
10 -
42 -
16 -
16 -
40 18 - 24 100
20 10 - 16 55
56 16 400
32 16 100
50 18 - 36
25 12 - 18 150
100 18 42 100 - 500
57 16 400
41 12 - 24 250
33 1/2 16 350
ENGINE
SITE CAPACITY
(hp) cu/yds/hr
11 15 60 - 90
1 1/2 15
17* 40 80
3 40-80
2 27-50
3-50 38 1000
17* 40
3 - 20 20 30
7 1/2 60
Hydraulic
Note: All conveyors are portable except the Clearfield D-2,3 which is a frame conveyor.
39
-------
Fig. 27. Mobile Frame Conveyor
-------
CONVEYOR BELTING MATERIAL
As previously discussed, four different types of conveyor belts were
tested to evaluate their performance in harvesting oil/sorbent materials
The only type of belt that would self-load oil sorbents was the wire
mesh belt, and therefore it was the only one included in a survey of
availability.
Three different sizes and two types of wire mesh (Figs. 16 and 17) were
evaluated in the test program. They all performed equally well and are
recommended for use. The specifications of these belts are given in
Table 10. There are literally several hundred different sizes and types
of wire belts available commercially from manufacturers throughout the
country. Time and funding did not permit the evaluation of more than a
few belts. However, some recommendations concerning the proper belting
to use are given below.
• Openings in the wire belts should between 1/4 in. and 1
in. Smaller openings might clog when used with very
viscous oils, and openings greater than 1 in. might allow
certain sorbents to pass through.
• The wire gauges of the wire belts should be between 8 and
20. Lighter gauges might break with heavier use and
heavier gauges might not be flexible enough to bend around
the head and tail pulleys of the conveyor.
• Use of the flat wire belt requires removing the friction
pulley at the other end of the belt and replacing it with
appropriately sited gears for a direct drive.
E 18-16-12
(equalized
spiral wound)
F-l/2 x 1/2
(flat wire)
E 30-30-44
(equalized
spiral wound)
Table 10
SPECIFICATIONS OF WIRE MESH BELTS
MESH
DESIGNATION
APPROX .
MESH SIZE
(IN.)
DIA OF
WIRE
(IN.)
ULTIMATE
STRENGTH
(IN.)
APPROX .
WT/SQ FT
OF BELT (LB)
3/4
1/2
3/8
0.1055
0.1205
0.08
11050
700
12880
2.04
2.50
1.35
41
-------
The biggest drawback in using wire mesh belting on the conveyors is
relative availability. Almost all frame and portable conveyors available
for rent come with smooth rubber or flighted rubber belts. This requires
that the rubber belts be removed and replaced with wire mesh belts, a
procedure which takes two men approximately 1/2 hour. Normally proper
wire mesh belts are not readily available for purchase or rental in a
few hours' time. Most wire mesh belting is made to order- The lag
time on ordering wire belting is from 5 days to 3 weeks. It is there-
fore recommended that intended users of the oil/sorbent harvester
system purchase the required wire mesh belting before an oil spill
incident occurs and stockpile the belting at their own facilities. Wire
mesh belting costs between $1.50 and $3.00 per sq ft, depending on the
type and quantity purchased. Table 11 lists some of the major manu-
facturers of wire mesh belts.
Table 11
LARGE MANUFACTURERS OF WIRE MESH BELTS
FMC Corp., Link Belt Division, Chicago, 111.
Alloy Wire Belt Co., San Jose, Calif.
U.S. Steel, Cyclone Fence Division, Pittsburgh, Pa.
Conveyor Systems, Inc., A.B. Farquhar, Morton Grove, 111.
Cambridge Wire Cloth Co., Cambridge, Maryland
Ashworth Products, Inc., Metal Products Div., Worcester, Mass.
Allied Steel & Conveyors, Detroit, Mich.
Rapistan, Inc., Grand Rapids, Mich.
Standard Conveyors, St. Paul, Minn.
Hytrol Conveyor Co., St. Louis, Mo.
Robins Conveyor Co. - Hewitt Robins Div., Passaic, N.J.
CF&I Steel Corp., Trenton, N.J.
E.W. Bushman Co., Cincinnati, Ohio
Matthews Conveyor Co., Div. Rex Chain Belt, Ellwood City, Pa.
SORBENT SPREADING EQUIPMENT
The only type of sorbent spreading equipment tested was the power
mulcher, a machine which has gained wide acceptance in oil spill control
for its ability to disperse large quantities of sorbents onto a spread-
ing oil slick.
Mulch spreaders (Fig. 28) are designed specifically for the fast dis-
tribution of mulch materials to assist in the control of soil erosion.
They are equipped with a discharge spout designed to move a full 360
degrees horizontally and 75 degrees vertically, thus allowing the
operator to spread the mulching material without repositioning the
mulcher. Mulchers have been used iii oil spill control by mounting them
42
-------
Fig. 28. Mulch Spreader
on boats and dispersing straw and/or polyurethane foam over oil slicks.
Two sizes are generally available: a large trailer-mounted mulcher with
a 9-ton/hr (straw) capacity, and a smaller skid-mounted mulcher of
4 ton/hr capacity. Table 12 presents the specifications of mulching
equipment.
Table 12
POWER MULCHER SPECIFICATIONS
MODEL
AND
MANUFACTURER
Finn -Ban tarn
Finn Mulch Spreader
Reinco. TM7-30
Reinco. M60F6
MOTOR
SIZE
(HP)
30
110
30
124
MOUNTING
Skid or Trailer
Trailer
Skid
Trailer
CAPACITY
(TONS
STRAW/HR )
4
10
4
9
43
-------
The short-term availability of power mulchers is somewhat less than
that of the other oil/sorbent harvester components. The largest source
would be the State Highway Department which uses them for erosion con-
trol on steep highway cuts. The largest commercial source would be
professional seeding companies which utilize them to spread protective
covers over large-scale seeding projects.
SPECIAL MATERIAL-HANDLING EQUIPMENT
The physical recovery of large quantities of oil and sorbents requires
appropriate handling and storage equipment. Most vessels will be limited
in their capacity and require periodic unloading. In the course of the
study various handling and storage systems were investigated, together
with associated onshore support facilities. The oil/sorbent material-
handling equipment can be broadly classified as:
• Onboard storage equipment
• Onboard material-transfer equipment
• Onboard and/or onshore lifting or hoisting equipment.
i
Onboard Storage Equipment
Large metal bins such as high-volume trash containers commonly called
"debris boxes" (Fig. 29) were utilized during Phase III of the test
program and found to be very suitable for use in the oil/sorbent har-
vesting system. The debris boxes range in size from 5 to 40 cu yd
capacity with 10- and 15-cu yd boxes being the most common size. For
general application on LCM-size vessels the debris boxes are simply
placed under the unloading end of the conveyors collecting and storing
the oil/sorbent coming off the conveyor belt. When the debris box is
full the vessel goes to an unloading station, unloads the full box and
receives an empty one. For use on larger pickup vessels such as deck
barges, LCUs, and Gulf Coast work boats, a multiple array of debris
boxes can be placed on the open deck areas and loaded by using transfer
equipment between the pickup conveyors and the debris boxes. The avail-
ability of debris boxes is generally very good as there are many firms
in metropolitan areas that specialize in renting them for commercial
use. Table 13 lists the specifications of some debris boxes.
Another possible oil/sorbent storage method applicable to smaller
pickup vessels such as LCMs and LCVPs is the use of a cargo net or
tarpaulin. The large nets or tarpaulins can be lined with polyethylene
plastic and placed underneath the unloading end of the conveyors.
Fresh tarps or nets would be placed on the straw pile for every 2 ft
of height. The tarpaulin or net could be offloaded by crane at an
unloading point.
44
-------
Fig. 29. Debris Box
Table 13
SPECIFICATIONS OF CONTAINERS AND BINS
COMPANY & MODEL
Hobbs
Hobbs
CO 300
HFL 2
3
4
5
6
7
8
Anchor Pac . 2022
2522
3022
4022
DIMENSIONS (WxLxH) CAPACITY (cu yd) WEIGHT (Ib)
8' x 16'8
3' x 6*
to
5'6" x 6
22' x 8
22' x 8
22' x 8
22' x 8
" x 6'8"
x 3'
' x 6'8"
1 x 41"
' x 51"
' x 61"
' x 81"
30
2
3
4
5
6
7
8
20
25
30
40
5800
6350
6600
6910
7740
45
-------
MATERIAL-TRANSFER EQUIPMENT
The side-mounted conveyor configurations and/or the utilization of high-
storage-capacity vessels would require the use of onboard transfer
equipment such as gravity-type chutes or flat (side-loading) conveyors,
to direct harvested sorbents on board the vessel and into the proper
storage container. On smaller vessels with the conveyors in the side-
mounted configuration, gravity chutes would suffice to direct the col-
lected sorbents into storage containers. On larger vessels with multiple
storage containers available for use, the flat conveyors with adjustable
discharge chutes essentially identical to frame conveyors would be ideal
for sorbent transfer. Figure 30 depicts a typical flat conveyor trans-
fer installation on a deck barge. The flat transfer conveyor is fixed
to the tops of the debris boxes it fills. Gravity chutes direct the col-
lected sorbent from the unloading end of the pickup conveyor to the trans-
fer conveyors. Since sorbent pickup is not required, smooth rubber belts
which normally come on this equipment would work very well.
Onboard and/or Onshore Lifting or Hoisting Equipment
The major requirement for hoisting equipment is to transfer oil/sorbent-
loaded debris boxes from pickup vessels on to floating storage barges
or a shore storage facility. Storage barges could use a portable truck
or crawler-mounted crane which could be driven onboard or lashed down to
the barge, or utilize a barge with a permanent crane installed (common
in the marine construction industry) . Shore storage facilities could
use the same truck or crawler-mounted cranes or the larger portable and
locomotive cranes which run on tracks by dockside. Since there is a
great variety of cranes available in any port facility, individual types
will not be considered in this report. The major requirement in crane
selection is that the heaviest lift that has to be made does not exceed
the crane's hoisting capacity. This could become a problem if the larger
(30-to-40-cu yd) debris boxes were used as the primary storage con-
tainers. The combined weight of a 40-cu yd debris box and its contents
could be as great as 30 tons, which would exceed the capacity of many
mobile (i.e., truck/crawler-mounted) cranes. Therefore, selection of
the proper size debris boxes should also consider the lifting capacity
of available cranes.
46
-------
Fig. 30. Flat Conveyor Installed on Deck Barge
-------
Section VI
INSTALLATION PROCEDURES (LCM)
The installation procedures required to install conveyors and associated
equipment onto a landing craft (LCM) are given in this section. Table
14 lists the various operations required to complete an installation.
Table 15 lists each operation, the labor skill and number of each skill
required, and the time required under normal conditions to complete the
operation. A flow chart is given in Figure 31 describing the actual path
for the installation operation on an LCM. As shown, the entire system
can be completely assembled in 9 hours.
A detailed description of each operation follows.
Table 14
OPERATIONS REQUIRED FOR INSTALLATION OF
OIL/SORBENT RECOVERY SYSTEM ON LANDING CRAFT
OPERATION DESCRIPTION
A Fabricate Wing Support Structure
B Cut Hole in LCM Ramp and Convert
Conveyors to Wire Belts
C Construct Rear Conveyor Support and
Install Conveyors and Wing Support Brace
D Fabricate Wings and Install
E Fabricate Absorbent Guides arid Splash Shield
F Fabricate Flashings and Bullnose
G Install Debris Box
H Install Pumps - Separator
I Install Straw Blower
J (alternate) Gate-Removed Installation
K (alternate) Installation of Side-Mounted Conveyor System
49
-------
Equipment + LCM
Delivered to Site
Time required- critical path A-D, E-F/G/ -H = 9 hours
Fig. 31. Flow Diagram of Installation Aboard an LCM
Table 15
LABOR AND TIME REQUIREMENTS FOR INSTALLATION ON LCM
A.
B.
C.
D.
E.
F.
G.
H.
I .
OPERATION
Fabricate Wing Support
Structure (Dual Mount)
Cut Opening in Gate of LCM
and Convert Conveyors to
Wire Belts
Install Wing Support
Structure and Conveyors
in LCM
Fabricate Plywood Wings
and Bolt to Supporting
Structure
Fabricate Guides and
Splash Shield
Fabricate Flashings
and Bull nose
Install Debris Box
Install Pumps - Separator
Install Strawblower
LABOR NO. OF ELAPSED LABOR HRS
SKILLS LABOR TIME REQUIRED
REQUIRED SKILL (HR) (MAN HR) COMMENTS
Welder 3 4
Welder 2 2
Mechanic 1 \
Laborer 1 )
Welder 1 |
Laborers 2 > 2
Equipt . Opr . 1 )
Carpenter 11
Laborer 1 f
Carpenter 1 ) 2
Laborer 2 /
Welder 1 2
Sheetmetal
worker 1 1
Laborer 1 2
Carpenter 1 1
12 Includes measuring,
cutting and assembly
4 Includes initial
2 adjusting of tension
both operations done
simultaneously
Includes installing
8 conveyor motors
'. 4 '»'*''
" •! 6
T
g Operations conducted
simultaneously
Laborers 2 1/2 1
Mechanic 1 1
1
Laborer 1 1/2 1/2 Installed on separate-
Welder 1 1/2 1/2 vessel
50
-------
Operation A. Fabricate Wing Support Structure
This structure is a heavy-duty welded steel unit required to attach and
support the deflection wings. It must be sufficiently rigid to with-
stand both vertical and tangential forces, as well as the forward stress
resulting from motion through the water. A sketch of this apparatus is
shown in Figure 32.
1.0 Using 3-in. by 2-in. channel, weld together a rectangular
structure with the dimensions shown in Figure 32. Brace this
structure with steel plate triangles as required. Flanges
in the upper corners are used in the illustrated structure.
The purpose of this structure is to prevent twisting of the
deflector wings and conveyors.
2.0 Cut the conveyor tracks and supports to the dimensions shown from
at least 1-1/2 in. right angle stock. Weld the outer supports to
the frame constructed in Step 1.0 at an angle of 70 degrees minimum.
Cut and weld 1 by 2 in. channel supports as shown to complete this
structure. Attach the conveyor tracks to this frame. The spacing
between the tracks should fit the conveyor frames snugly. These
tracks will allow later installation of the conveyor with U-bolts
and provide for any required final adjustment.
This end welded to vessel
Figure 32. Wing Support Structure
51
-------
Operation A (Continued)
3.0 Attach right angle or light channel braces to complete support of
the structure.
/
4.0 Fabricate wing attachment pads out of 24 in. by 8 in. by 1/4 in.
steel plate. Four plates will be required. Drill at least four
3/8 to 1/2 in. bolt holes (in pairs) in these plates to allow for
later matching. Set aside one of each pair for Operation E.
Weld remaining plates to the frame at an angle of approximately
30 degrees, as depicted in Figure 33.
5.0 Add braces and drill holes to complete structure shown in Figures
32 and 33.
6.0 A coat of primer is recommended if time permits.
Support strut
2" x 2" x '/IB" rt.
main support
.3/8» plate
2" x 3" x '/4" rt.^_ braces
Figure 33. Wing Attachment Plate Detail
52
-------
1.0
2.0
Operation B. Cut Hole in LCM Ramp and Install Belts
Mark the location of the hole (60 in. by 20 in. approx.) on the
inside and outside of the ramp. The bottom of the hole should
be just above the hinge line (Figure 34).
Using one welder inside and
one outside in a small boat,
cut out hole, using cutting
torches as shown in Figure
35.
3.0 Install belt.
3.1 Spiral woven belt (shown
in roll in Figure 36) .
3.1.1 Check conveyor drive
pulley for surface
roughness. Prominent
welded beads are
necessary to prevent
belt slippage, especi-
ally when oily. Sur-
face roughness may be
improved by welding
additional beads on as
shown in Figure 37.
3.1.2 Install belt and cut
to proper length if
necessary.
3.1.3 Adjust tensioning
bolts until 1 to 2
in. of play is
obtained between any
two adjacent rollers.
Fine adjustment may
IT
J IL
20"
lie/ U2/
60"
Figure 34. Typical Internal
Structures Encountered in
Hole Cutting
be required during operation.
3.2
3.2.1
3.2.2
Flat wire belt (shown on conveyor in Figure 36) .
belts require the installation of drive gears.
Flat wire
Remove standard drive pulley, bearings and shaft.
Mount drive gears and bearings on a keyed shaft, adjust
to mesh with belt, and install on conveyor as shown in
Figure 38.
3.2.3 Install wire belt and cut to proper length if necessary.
3.2.4 Adjust tension as in Step 3.1.2.
53
-------
• A r
. t-2 f
Fig. 35. Cutting a Hole in the LCM Ramp
Fig. 36. Recommended
Conveyor Belt Types
-------
Fig. 37. Increasing Surface
Roughness of Drive Pulley
Fig. 38. Installation of Drive Gears
55
-------
Operation C.
Construct Rear Conveyor Support and
Install Wing Support Structure and Conveyors
1.0 Sling the wing support structure into position as shown in Figure 39.
Figure 40 presents critical angles required in this operation. Weld
the rear of the wing support structure to the ramp as shown.
2.0 Using another crane, swing the converted conveyor belts into posi-
tion from the well deck side through the hole in the ramp.
3.0 Using U-bolts attach the conveyors to the conveyor tracks on the
wing support frame.
4.0 The rear conveyor support consists of a piece of thick wall steel
pipe or box section channel. Its location is arbitrary, but should
be under or aft of the conveyor motors, if possible. It is most
convenient to rest the support across the top of the well deck and
slide it forward until the proper position is obtained. The support
is then welded in place. If the specific I£M does not permit this,
the pipe may be attached to the walls of the well deck. This is
best accomplished by cutting the support narrower than the width of
the well deck and attaching it to the conveyors with U-bolts. The
ends of this support are in turn welded to the sides of the well
with right angle brackets as shown in Figure 41.
5.0 Install a support attached to the center of the rear support at
right angles to the conveyors and running to the well deck.
Fig. 39. Installation of Wing Support Structure
and Conveyor Belts
56
-------
about 6" submersion
minimum possible distance to
give proper submersion
Fig. 40. Critical Installation Angles
Fig. 41. Bracket Attachment of Rear Conveyor Mount
57
-------
Operation D. Fabricate Wings and Install
Standard wing size for relatively calm operating conditions is 2 ft by
8 ft. For rougher water, a greater wing height will be required to pre-
vent material from passing underneath. The material to be used is
either 1-1/2 in. or (preferably) two 3/4-in. sheets of laminated
exterior plywood.
1.0 Saw plywood into proper sizes.
2.0 Construct a rectangular supporting structure for each wing, as
shown in Figure 42. This structure should be at least 1-1/2 in.
right angle steel, with the exception of the attachment plate
which was constructed in an earlier operation. The size of the
frame should be slightly less than that of the plywood wing.
3.0 Drill holes in the frame as required to attach the plywood.
4.0 Assemble and bolt wings to LCM, as shown in Figure 43.
5.0 Construct deflector tips from at least 1/8 in. sheet metal. These
deflectors reduce the loss of sorbent around the wing tips. They
must be bent to parallel the keel of the vessel when bolted in
place .
6.0 Install channel iron struts to support the wings. These struts
must be installed to meet the requirements for each installation.
A typical installation is shown in Figure 44.
58
-------
Attachment Plate
]/4" plate
holes to match box structure
CONSTRUCT WINGS OF TWO SHEETS OF 3A-in.
LAMINATED EXTERIOR PLYWOOD (OR ONE SHEET
1-1/2 in.)
Lifting Eye bolted to plywood
at the approximate center of gravity
Strut Attachment Plates
}/4" plate
Tip Deflector
!/4" plate
12" x 36"
welded to frame
Fig. 42. Wing Support Detail
Rt. side only
Left similar
59
-------
Fig. 43. Installation of Wings
Supporting
Struts
t^-
Fig. 44. Finished Installation Showing
Supporting Struts
60
-------
Operation E. Fabricate Guides and Splash Shield
Auxiliary guides along each side of the conveyors are required to pre-
vent spillage of sorbents before reaching the debris box. The installa-
tion of a splash shield is required when the ramp is removed or has a
hole cut in it. This shield consists of a false bulkhead to keep water
out of the well deck.
1.0 Sorbent guides should be fashioned out of 1/2-in. exterior ply-
wood. t Cut notches at the roller positions to allow the guides
to fit between the conveyor frame and the belt. The height of
the guides should be 6 in. above the belt. A typical installa-
tion is shown in Figure 45.
2.0 Attach the guides'to the conveyors by one of the methods shown in
Figure 46, using steel bolts. Method A reduces the space between
the belt and the guide to a minimum, but is not as sturdy as
Method B. Guides should be installed the entire length of the
conveyors. The inboard guide is not needed with side-mounted
installations.
3.0 The splash shield should be constructed of 3/4-in. exterior plywood
and fastened to the vessel as securely as possible.
3.1 Gate Removed. Fashion a false bulkhead to fit across
the width of the well deck at a point that is usually
about 3 to 4 ft from the bow. A representative instal-
lation is shown in Figure 47. Joints between the bulkhead
and the LCM should be sealed with foam rubber.
3.2 Hole Cut in Gate. This mode greatly reduces the amount
of water shipped. The shield in this case consists of a
box attached to the bottom of the conveyors, as shown in
Figure 48.
61
-------
Sorbent Guides
Method B
Fig. 45. Sorbent Guide Installation
62
-------
Fig. 46. Installation of
Sorbent Guides
Fig. 47. Splash Shield,
Gate Removed
Fig. 48. Splash Shield,
Conveyor Installed Through
Hole Cut in Gate
63
-------
Operation F. Fabricate Flashings and Bullnose
The lower end of the conveyor presents an irregular surface that tends
to entrap and entangle absorbents and create turbulence. This phenom-
enon can be overcome by adding sheetmetal streamlining or flashings.
1.0 A streamlined structure (bullnose) must be constructed between
the conveyors. This structure should be designed to withstand
side as well as head-on forces. A schematic diagram of the
installation is presented in Figure 49.
1.1 Construct the framework from 1 by 2-in. channel to the
dimensions indicated.
1.2 Attach 2 by 3-in. channel to secure the bullnose to the
wing support structure.
1.3 Cover the leading edge of the bullnose with heavy gauge
sheetmetal.
1.4 Install the bullnose as shown in Figure 50. Attach support
strut from top of bullnose to top of wing support structure.
2.0 Additional plywood flashing must be attached to the bullnose to
prevent loss of absorbent between conveyors. The approximate shape
and location of these flashings are shown in Figure 51.
2.1 Cut and install the triangular side pieces from 3/4-in.
exterior plywood to suit individual installation.
2.2 Brace the structure internally with 2 by 4s.
2.3 Install a rectangular piece to complete the structure. In
addition to strengthening the structure, this piece provides
an emergency work platform.
3.0 Additional flashings must be added around the conveyor tips, using
sheetmetal. A typical installation is shown in Figure 52.
64
-------
Support strut attached
Lifting eye
.1" x 2"
sheet metal
( bolted)
18"
Fig. 49. Bull Nose
65
-------
Fig. 50. Installation of
Bull Nose
Fig. 51. Bull Nose
Flashings
66
-------
Fig. 52. Additional Bull Nose Flashings
67
-------
Operation G. Installation and Removal of Debris Box
1.0 Select debris boxes 3 to 4 ft shorter than the available space
(Figure 53) to allow for easier manipulation of the box,
especially during an at-sea transfer -
2.0 Usually, two stages of slinging are required.
2.1 The box is lowered from the dock in a level attitude by
4-point suspension. It is set in the LCM at an angle.
2.2 The forward slings are removed and the box hoisted slightly,
causing it to slide forward into position.
3.0 Removal requires a reverse operation.
3'-4' shorter than available space
Figure 53. Installation of Debris Box
68
-------
Operation H. Install Pumps and Storage Tanks or Separator
During operation water will be taken aboard from a variety of sources,
including water brought aboard by the wire belts, water draining from
the recovered sorbent, and spray- This water must be removed to prevent
serious listing.
*
1.0 Install pumps (two should be carried for backup purposes). The
intake hose should be placed in the bilge access at the rear center
of the well deck (Figure 54) .
2.0 As this water will almost certainly be oily; it should not be dis-
charged overboard. Either install tanks to receive this material or
install a small A.P.I, or C.P.I, separator.
Figure 54 . Installation of High Capacity
Bilge Pumps
69
-------
Operation I. Install Straw Blower
1.0 The straw blower should be installed aboard any vessel of
sufficient size to carry a large cargo of straw. (Another LCM
would be ideal.) It may be mounted in the bow or the stern.
2.0 Position the blower to allow easy loading (Figure 55) of sorbent.
3.0 Weld the blower to the vessel if possible or lash it securely.
Figure 55. Typical Strawblower Installation
on Bow of Modified LCM
70
-------
Operation J. Harvesting System Installation with Gate Removed
The harvester system may be installed by completely removing the LCM
loading gate. This configuration has the advantage of allowing greater
visibility. It does, however, severely limit the sea state in which
safe operation is possible. Other than for calm harbor applications,
this installation is not recommended.
1.0 Remove the gate by lowering partially on sling and removing hinge
pins.
2.0 Assemble the conveyor's wing support and wings on the dock. Bolt
the rear conveyor mount (a heavy pipe or channel) to the conveyor.
3.0 Sling the conveyor into approximate position as shown in Figure 56
7n
Fig. 56. Installation of Conveyor Assembly,
Gate Removed
71
-------
Operation J (Continued)
4.0 Adjust the position of the assembly to a maximum of 20 degrees to
the water surface.
5.0 Weld short lengths of right angle stock to the hinge line to form
tracks for the conveyors, as shown in Figure 57.
Conveyor Mounts
« I
Fig. 57. Installation of Forward Conveyor Mounts
6.0 Adjust the position of the conveyors on the tracks so that
slightly less than half of the deflector wings are submerged.
(The depth of the wings will increase with subsequent loading.)
U-bolt or weld conveyors in place.
7.0 Using right angle brackets as described in Operation D, affix
the rear conveyor mount to the LCM. Attach the vertical support
strut.
72
-------
Operation J (Continued)
8.0 Install a false bulkhead under the conveyor assembly to prevent
shipping of water. Seal all joints with 1/4-in. neoprene gaskets
Note chain for ballast (Figure 58) used to adjust final trim
of vessel.
Fig. 58. Splash Shield Installation with Gate Removed
9.0 Attach sheetmetal flashing to conveyor tip as described in
Operation G.
10.0 Install conveyor motor and adjust alignment of belt.
73
-------
Operation K. Installation of Side-Mounted Conveyor System
The wing supporting structure consists essentially of one half of the
standard bow support structure.
1. Construct either left, right, or both halves of the wing supporting
structure, as outlined in Operation A.
2. Attach wire belt-modified conveyor to wing supporting structure
(26 ft conveyors required).
3. Fabricate a deflector wing as described in Operation E and attach'
to wing supporting structure. Attach absorbent guides as outlined
in Operation F.
4. Sling completed assembly and position alongside LCM in approximate
installation position. Figure 59 gives guidelines for determining
this position.
5. Weld steel channel or pipe
to LCM in approximate
installation position as
shown in Figure 60 to
form rear support for con-
veyor- An additional
channel brace from the
deck level to the out-
board side of this
mounting provides
additional support.
6. Weld forward end of
assembly to hull as close
as possible to waterline
(Figure 61).
7. Fabricate wooden chute to
direct absorbent into
debris box (Figure 62).
8. Attach cables and channel
iron as required to support
wing structure. A typical
installation is shown in
Figure 63.
/
\
M
Position conveyor
behind flare of bow
Fig. 59. Positioning Side-Mounted
System on LCM
74
-------
Rear conveyor mounting - pipe
Brace
Weld to hull
Fig. 60. Rear Conveyor Mount
and Supplementary Brace
T,/
Fig. 61. Forward Waterline
Attachment of Assembly
75
-------
Fig. 62. Chute Detail
r~f t i
Fig. 63. Finished Installation Showing
Supplementary Braces
76
-------
Section VII
INSTALLATION PROCEDURES (CONVENTIONAL VESSEL) '
The installation procedures required to install conveyors and associated
equipment onto any vessel of opportunity (e.g., Gulf Coast work boats,
deck barges, large tug boats, etc.) other than an LCM are given in this
section. The procedures are similar to those for the side-mounted
installation on an LCM type vessel. Table 16 lists the various opera-
tions required to complete an installation. Table 17 lists each
operation, the labor skill and number of each skill required, and the
time required under normal conditions to complete the operation.
A detailed description of each operation follows.
Table 16
OPERATIONS REQUIRED FOR INSTALLATION OF OIL/SORBENT RECOVERY
SYSTEM ON VESSELS OTHER THAN LANDING CRAFT
OPERATION DESCRIPTION
A Fabricate Wing Support Structure
B Convert the Conveyors to Wire Belts
C Construct Rear Conveyor Supports
D Fabricate Wings and Install
E Fabricate Absorbent Guides
F Attach Assembly to Vessel
G Fabricate Flashings
H Construct Debris Chute
I Installation and Removal of Debris Box
J Installation of Pumps and Separator
77
-------
Table 17
LABOR AND TIKE REQUIREMENTS FOR INSTALLATION ON CONVENTIONAL VESSEL
oo
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
OPERATION
Fabricate Wing Support
Structure (Dual Mount)
Convert Conveyors
to Wire Belts
Construct Rear Support
Fabricate Plywood Wings
and Bolt to
Supporting Structure
Fabricate Sorbent
Guides
Install Assembly
on Vessel
Fabricate Flashings
Construct Chute
Install Debris Box
Install Pumps
LABOR
SKILLS
REQUIRED
Welder
Mechanic
Laborer
Laborer
Welder
Carpenter
Laborer
Carpenter
Laborers
Welder
Laborers
Equipt. Opr.
Sheetmetal
worker
Carpenter
Laborers
Mechanic
NO. OF
LABOR
SKILL
3
1)
1)
1)
1}
1}
1
1
2
1
TIME
REQUIRED
(MAN HR)
4
i
1
2
1
2
1
2
1/2
1
TOTAL
TIME
(MAN HR)
12
2
2
4
3
8
1
2
1
1
COMMENTS
Includes measuring,
cutting and assembly
Includes initial adjusting
of tension
Includes installing
conveyor
motors
-------
Operation A. Fabricate Wing Support Structure
This structure is essentially the same heavy duty welded steel unit
utilized in the LCM installation. One half of this structure is required
for each side mounting.
1.0 Using 3-in. by 2-in. channel, weld together a rectangular
structure with the dimensions shown in Figure 32. Brace this
structure with steel plate triangles as required. Flanges in
the upper corners are used in the illustrated structure. Cut
this structure into mirror halves, one for each side of the
vessel.
2.0 Fabricate wing attachment pads out of 24 in. by 8 in. by 1/4 in.
steel plate. Four plates will be required. Drill at least four
3/8 to 1/2 in. bolt holes (in pairs) in these plates to allow for
later matching. Set aside one of each pair for Operation E. Weld
the remaining plates to the frame at an angle of approximately
30 degrees, as depicted in Figure 33.
3.0 Add braces and drill holes to complete structure shown in
Figures 32 and 33.
4.0 A coat of primer is recommended if time permits.
79
-------
Operation B. Convert Conveyors to Wire Belts
1.0 Install belt.
1.1 Spiral woven belt (shown in roll in Figure 36).
1.1.1 Check conveyor drive pulley for surface roughness.
Prominent welded beads are necessary to prevent
belt slippage, especially when oily- Surface
roughness may be improved by welding additional
beads on as shown in Figure 37
1.1.2 Install belt and cut to proper length if necessary.
1.1.3 Adjust tensioning bolts until 1 to 2 in. of play
is obtained between any two adjacent rollers.
Fine adjustment may be required during operation.
1.2 Flat wire belt (shown on conveyor in Figure 36). Flat wire
belts require the installation of drive gears.
1.2.1 Remove standard drive pulley, bearings and shaft.
1.2.2 Mount drive gears and bearings on a keyed shaft,
adjust to mesh with belt, and install on conveyor
as in Figure 38.
1.2.3 Install wire belt and cut to proper length if necessary.
1.2.4 Adjust tension as in Section VI, Operation B.
80
-------
Operation C. Construct Rear Conveyor Support
1.0 Determine location of rear mount.
Figure 64 indicates the general configuration required.
Location of the rear mount may be determined mathematically
or by physically placing the conveyor in position and marking
the mount position.
2.0 Weld or otherwise attach a large diameter pipe to the deck of
the vessel at the position determined in Step 1.0. The support
should extend at least 6 in. plus the width of the conveyor
frame beyond the hull of the vessel.
3.0 An auxiliary brace from the outboard end of the rear support to
the hull is recommended.
o
Position conveyor
behind flare of bow
Fig. 64. Positioning Side-Mounted
System on Conventional
Vessel
81
-------
Operation D. Fabricate Wings and Install
Standard wing size for relatively calm operating conditions is 2 ft by
8 ft. For rougher water, a greater wing height will be required to
prevent material from passing underneath. The material to be used is
either 1-1/2 in. or (preferably) two 3/4-in. sheets of laminated exterior
plywood.
1.0 Saw plywood into proper sizes.
2.0 Construct a rectangular supporting structure for each wing, as
shown in Figure 42. This structure should be at least 1-1/2 in.
right angle steel, with the exception of the attachment plate
which was constructed in an earlier operation. The size of the
frame should be slightly less than that of the plywood wing.
3.0 Drill holes in the frame as required to attach the plywood.
4.0 Assemble and bolt wings to support structure.
5.0 Construct deflector tips from at least 1/8 in. sheet metal.
These deflectors reduce the loss of sorbent around the wing tips.
They must be bent to parallel the keel of the vessel when bolted
in place.
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Operation E. Fabricate Guides
Auxiliary guides along each side of the conveyors are required to pre-
vent spillage of sorbents before reaching the debris box.
1.0 Sorbent guides should be fashioned out of 1/2-in. exterior ply-
wood. Notches must be cut at the roller positions to allow the
guides to fit between the conveyor frame and the belt. A
typical installation is shown in Figure 45.
2.0 Cut "bracelet" from strap steel stock to a sufficient length
to allow attachment of sorbent guides as shown in Figure 46.
3.0 Attach the brackets to the conveyors by one of the methods shown
in Figure 46, using steel bands. Method A reduces the space between
the belt and the guide to a minimum, but is not as sturdy as Method B.
Guides should be installed the entire length of the conveyors.
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Operation F. Attach Conveyor Assembly to Vessel
1.0 Lower the assembly into position alongside hull. Adjust the angle
of the conveyors to the water to 20 degrees and have the conveyor
tip about 6 in. below the water.
2.0 Attach the conveyor support structure to the vessel near the
water line .
3.0 Attach the assembly to the rear mount with U-bolts.
4.0 Attach additional struts and/or cables to support the deflecting
wings.
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Operation G. Fabricate Flashings
The lower end of the conveyor presents an irregular surface that tends
to entrap and entangle absorbents and create turbulence. This phenom-
enon may be overcome by adding sheetmetal streamlining or flashings.
Application of streamlining is as required by the individual installa-
tion .
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Operation H. Construct Debris Chute
A chute is required to transfer material from the end of the conveyor
to the collection container. Detail of a typical installation is
indicated in Section VI.
Construct the chute of 3/4 in. exterior plywood. The assembly is
bolted to the rear of the conveyor.
As each installation will vary, this chute will vary in size and
position. Ideally, gravity feed is intended; however; manual assistance
in moving the material down the chute may be required .
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Operation I. Installation and Removal of Debris Box
1.0 Select debris boxes 3 to 4 ft shorter than the available space
(Figure 53) to allow for easier manipulation of the box,
especially during an at-sea transfer.
2.0 Lower the box from the dock in a level attitude by 4-point
suspension. It is set on the deck of the vessel and the
slings removed. Removal of the debris box requires a reverse
operation.
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Operation J. Install Pumps and Storage Tanks or Separator
During operation water will be taken aboard from a variety of sources,
including water brought aboard by the wire belts, water draining from
the recovered sorbent, and spray. This water must be removed to pre-
vent serious listing.
1.0 Install pumps (two should be carried for backup purposes). The
intake hose should be placed in the ship's bilge.
2.0 As this water will almost certainly be oily; it should not be
discharged overboard. Either install tanks to receive this
material or install a small A.P.I, or C.P.I, separator-
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Section VIII
OPERATIONAL PROCEDURES
Based on the limited full-scale test program conducted in this study,
both the operational procedures and cost estimates for implementing the
oil/sorbent harvesting system are presented in this section. The proper
utilization of the proposed system depends upon several factors,
including
• Sea state (wind and currents)
• Availability of vessels of opportunity
• Characteristics of oil spilled
• Type of sorbents available.
An oil spill is typified by the rapid dispersion of the spilled oil
through the combined action of currents, wind, and the oil's own
spreading force.
In previous oil spill incidents where sorbent material (principally
straw) has been used, no effective method was available for the recovery
of the oil-soaked sorbent and large quantities washed ashore, necessi-
tating additional expenditure of cleanup effort. The effective use of
sorbents requires a system that considers both rapid dispersal of
sorbents and effective and rapid harvesting techniques.
The operational procedures described in the following paragraphs have
been included to assist in the effective utilization of the oil/sorbent
harvesting system evaluated in this study.
SORBENT DISPERSAL
During the course of this research study, two types of sorbents were
tested: straw and polyurethane foam. Both of these sorbents were dis-
persed utilizing a power mulcher (described in Section V). The most
efficient method of dispersal found was to disperse the sorbent downwind
onto the oil slick. The forward speed of the vessel on which the power
mulcher is mounted should be between 1 and 2 knots; faster speeds would
inhibit proper coverage of the oil. In the case of straw, one power
mulcher can disperse up to 10 tons of straw per hour; this would
effectively cover an area of 120,000 sq ft. The contact time (i.e.,
the time the sorbent is allowed to remain in contact with the oil
before harvesting is initiated) varies considerably with different
sorbents and different oils, ranging from less than 1 minute with
certain types of polyurethane foam to at least 1/2 hr when straw is
used. Contact time can best be judged on-site during actual operations
89
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through visual observation; when the sorbent appears to be oil-soaked,
commence harvesting operations.
HARVESTING PROCEDURES
The major consideration involved in harvesting oil/sorbents is to work
with the prevailing elements (i.e., wind, currents). The sorbent
recovery vessel should initiate the harvesting operation on the down-
wind side of the oil slick making as long a pass through the oil/sorbent
area as is feasible.
In most cases, the prevailing wind on a coast is onshore (i.e., blows
toward the shoreline); therefore, the above procedure would help allevi-
ate oil contamination of beaches and shorelines. If currents are
present in the affected area, it is best to have the sorbent recovery
vessel work into or against the current in order to maximize recovery.
The forward speed of the sorbent recovery vessel should be between 2
and 4 knots; higher speeds might place undue strain on the deflecting
wings and also cause loss of sorbents under the wings due to turbulence.
SORBENT RECOVERY RATE
The recovery rate of the oil/sorbent harvester system is highly vari-
able depending on many factors such as wind, thickness of sorbent
spread, curents, etc. However, the tank tests and full-scale tests
conducted in this study indicate a pickup range between 4,000 and 7,000
Ib of dry straw per hour for a dual conveyor system. The actual oper-
ating rate of the oil/sorbent system would also depend on the storage
capacity of the pickup vessel. Smaller vessels that can hold only a
single debris box, such as the LCM-6, would require more frequent
unloading, thus necessitating longer time spent in transit to and from
an unloading area. The sorbent recovery rate of the LCM-6 would be
approximately 3,000 Ib of dry straw per hour or 400 cu ft of polyurethane
foam. Oil recovery rate would depend on the sorbing ability but could
range from 940 gal/hr for straw with a 2.5 to 1 (weight basis) sorbing
ratio to 20,000 gal/hr for a polyurethane foam that has a sorbing ratio
of 25 to 1 (by weight). A larger pickup vessel, such as Gulf Coast
work boat that could store 14 to 15 cu yd debris boxes, thus requiring
fewer unloading trips, would be capable of picking up an average of
4,500 Ib/hr of dry straw. Figures 65 and 66 show typical vessel and
power mulcher requirements for different sized oil spills and
cleanup times.
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GALLONS
OF
Ol L SP1 LLEO
12 hour
work day
10 DAYS
5 DAYS
1 DAY
Ix 104
1234 567
NUMBER OF VESSELS/ DUAL CONVEYOR INSTALLATION
10
Fig. 65. Vessel Requirements for Various Oil Spill Sizes
and Cleanup Times
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TONS OF
STRAW
DELI VERED
100
10 days
1
NUMBER OF MULCHERS
at 10 tons/hour, 12 hours/day
Fig. 66. Number of Mulchers Required for Different Cleanup Times
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SUPPORT VESSELS
The primary support vessel for the system should be a large hopper or
deck barge equipped with a crane that can act as a floating storage
area for recovered oily straw or as a recycling plant for recovered
polyurethane foam. A barge 200 ft by 35 ft could store sixty-four
15-cu yd debris boxes, giving it a capacity of 960 cu yd. This is
sufficient to support five LCMs for a 12-hr work day.
COST ANALYSIS
The cost of fabricating and operating the oil/sorbent harvesting system
evaluated in this study can vary considerably depending on the vessel(s)
of opportunity utilized and the type of sorbent used. Geographical and
physical factors such as spill location, weather conditions, type of
oil spilled, and availability of equipment all tend to make accurate
cost estimates of the oil/sorbent harvester system difficult to fore-
cast.
However, Table 20 presents an estimate of costs for individual compon-
ents of the oil/sorbent harvester system. Almost all the costs are
for a daily rental rate or labor rate based on a 12-hr day. The main
exception is the initial installation cost where the two conveyors are
presumed to be rented for two weeks and the material and labor for
fabricating the systems comes to a one-time charge of $9000.
Table 21 shows four separate cost estimates for cleanup of a 200,000 gallon
oil spill in 5 days. An analysis of the table indicates that the largest
single cost factor is the capability of the sorbent to sorb oil. In the
least-cost case, the use of polyurethane foam that could sorb up to 25 times
its own weight in oil^5' would enable the oil spill to be cleaned up for
approximately $30,000. However, other sources(">7) citing more recent work,
indicate that under actual conditions, much lower sorbing ratios could be
expected, such as 2.5 or 5 to 1 (by weight). Using a lower sorbing ratio
(i.e., 2.5 to 1), the cost of cleaning up a 200,000 gallon oil spill would
be more than tripled, to over $100,000. (Sorbing ratios are based on weight
of oil sorbed versus weight of sorbent. One cubic foot of straw weighs
eight times as much as 1 cubic foot of polyurethane foam.)
The major reason for the large increase in cost is the low sorbing ratio of
the foam. In this case 1 cu ft of polyurethane foam would pick up only
approximately 0.6 gallon of oil, with the result that a full boatload of
oil-soaked foam would represent only 250 gallons of oil. Therefore, in
order to clean up the 200,000 gallon spill in 5 days, 14 LCMs would be
required. Cost estimates were also prepared for different types of pickup
vessels, using straw as a sorbent. The cost differences between the LCMs
and Gulf Coast work boats were slight ($56,000 vs $59,000). The cost esti-
mates that have been prepared are estimates based on ideal conditions and
do not include supervision and shore cleanup and support.
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Table 20
COST ESTIMATE FOR INDIVIDUAL COMPONENTS
OF OIL/SORBENT HARVESTER SYSTEM
Initial Costs - Sorbent Harvesting System
$
250
200
450
$
900
700/2 wk period
Belts
Deflector Wing Material
Fabrication - Labor
Conveyor Rental (2 units)
LCM Daily Operating Costs
LCM $400/day
Pumps and fittings 100/day
Labor 120/day
$620/day
Sorbent Boat Operating Costs
Boat $400/day
Mulcher 30/day
Labor 120/day
$550/day
(Sorbents: straw = $50/ton; polyurethane foam = $l/cu ft,
2 Ib/cu ft density)
$ 1600/vessel
Gulf Coast Work Boat
Boat and Crew
Pumps and fittings
Labor
$ 800/day
100/day
120/day
$1120/day
Storage Barge (100' long) and
Tugboat Operating Costs
Debris box (18 units) @$30
Crane
Barge and Tugboat
Labor
200'-long Barge
Debris box (64 units) @$30 $1920
Crane 120
Barge and Tugboat 1000
Labor 310
$3350/
day
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Table 21
COST ESTIMATE FOR VARIOUS COMBINATIONS OF
OIL/SORBENT HARVESTER SYSTEM
200,000 gallon oil spill, 5-day cleanup cycle, 12-hr day
1. 4 LCM's , 1 Straw Boat, 1 200-ft Barge with Tug
Sorbent: Straw, sorbing ratio 2.5:1
4 LCM's - 5 days
Initial Cost - 4 x $1,600 $ 6,400
Daily Cost - $620 x 4 x 5 12,400
1 Straw Boat - 5 days x $550 22,750
Straw - 72 tons/day x 5 days x $50/ton 18,000
1 - 200-ft Barge and Tug, $3,350/day x 5 16,750
$56,300
2. 14 LCM's, 5 Sorbent Boats, 1 200-ft Barge and Tug with Recycling Equipment
Sorbent: Polyurethane foam, sorbing ratio 2.5:1 with total recycling
14 LCM's - 5 days
Initial Cost - 14 x $1,600 $22,400
Daily Cost - $620 x 14 x 5 43,400
5 Sorbent Boats - 5 x 5 x $550 13,750
Foam - 14,000 cubic ft at $1.00/cubic ft 14,000
1 - 200-ft Barge, Tug, and Crane at $1,430 x 5 7,150
28 Debris Boxes - $840 840
$101,540
3. 2 LCM's, 1 Sorbent Boat, 1 200-ft Barge and Tug with Foam Recycling Equipment
Sorbent: Polyurethane foam, sorbing ratio 25:1 with triple recycle
2 LCM's - 5 days
Initial Cost - 2 $1,600 $ 3,200
Daily Cost - $620 x 2 x 5 6,200
1 Sorbent Boat - 5 x $550 2,750
Foam - 11,000 cubic ft at $1.00/cubic ft 11,000
1 - 200-ft Barge, Tug, and Crane $1,430 x 5 7,150
4 Debris Boxes at $30 120
$30,420
4. 3 Gulf Coast Work Boats, 1 Straw Boat, 1 200-ft Barge and Tug
Sorbent: Straw, sorbing ratio 2.5:1
3 Gulf Coast Work Boats at $800/day x 5 days
Initial Cost - 3 x $1,600 $ 4,800
Daily Cost - 3 x $1,120 x 5 days 16,800
1 Straw Boat - 5 days x $550 2,750
Straw - 72 tons/day x 5 days x $50/ton 18,000
1 - 200-ft Barge and Tug - $3,350/day x 5 16,750
and Debris Boxes $59,100
Pick-up rate for LCM's: 72 tons dry straw/day = 45,000 gallons oil/day.
95
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Section IX
ACKNOWLEDGMENTS
This report summarizes research conducted by URS Research Company for
the U.S. Environmental Protection Agency, under Contract No. 68-01-0069
during the period June 14, 1971 through June 14, 1972. The work was
performed under the direction of Dr. Franklin J. Agardy, Executive Vice
President and Director of the Environmental Systems Division. Mr- James
D. Sartor served as Project Manager and Mr. Carl Foget and Mr. Robert
Castle were Assistant Project Managers.
We also wish to thank the following URS Research Company staff members
who assisted in the full-scale field testing:
Robert Pitt Photography
John Butt Boat Handling
Charles Brennen Sorbent Dispersal
Dan Walters Test Engineer
Mrs. Patty Reitman was responsible for editing and production of the
report and Miss Sherry Hossom and Mrs. Ceevah Sobel prepared the
illustrations.
Murphy Pacific Salvage Co. provided on-site support services in the
San Francisco Bay and the Black Diamond Towing Service supplied the
LCM for use both in the San Francisco Bay tests and at Santa Barbara
(Coal Oil Point).
Mr. Charles Wilton of Scientific Services was responsible for the con-
struction of the test platform and also provided on-site support during
the full-scale field testing at both the San Francisco Bay and Santa
Barbara (Coal Oil Point).
URS Research Company also wishes to thank Mr. Stephen Dorrler, of the
Edison Water Quality Laboratory, Environmental Protection Agency, for
his generous assistance and guidance while serving as Project Officer.
97
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Section X
REFERENCES
Oil Spill Treating Agents, A Compendium, Battelle Northwest,
Richland, Washington, May 1, 1970
Systems Study of Oil Spill Cleanup Procedures, Volumes I and II,
Dillingham Corporation, La Jolla, Calif., February 1970
Evaluation of Selected Earthmoving Equipment for the Restoration
of Oil-Contaminated Beaches, URS Research Co., San Mateo, Calif.,
October 1970
Proceedings - Joint Conferences on Prevention and Control of Oil
Spills, December 1969
Fraser, J.P., Oil Spills Containment and Removal, National Safety
Congress and Exposition, Chicago, Illinois, October 1971
Guntz, Garth, Personal Communication, Meley Laboratories,
Springfield, Virginia, May 1972
Fraser, J.P., Personal Communication, Shell Pipeline Corporation,
June 1972.
99
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SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
/. R*.
w
OIL/SORBENT HARVESTING SYSTEM FOR USE ON
VESSELS OF OPPORTUNITY
s.
~fc:rr.
Sartor, James D., Foget, Carl R., Castle, Robert W.
URS Research Company
155 Bovet Road
San Mateo, California 94402
15080 HER
68-01-0069
>i'.
ic.a U.S. Environmental Protection Agency 0R&M
Ty;.
r -ice
Environmental Protection Agency report
number, EPA-R2-73-166, April 1973.
A system for harvesting mixtures of oil and sorbent materials, primarily straw, which
could be utilized for the recovery of floating oil from water was developed for use on
vessels of opportunity.
A three-phase test program was conducted to evaluate candidate system components and
operating specifications for the oil/sorbent harvesting system. The first phase of the
program involved testing individual system components and operating parameters as to
their effectiveness in picking up sorbents only. The first phase was conducted under
actual conditions in a saltwater slough. The second phase of the test program entailed
evaluating those operating characteristics of the harvesting system components selected
in the first phase using crude oil and various sorbents in a test tank. The third phase
of the test program entailed the installation of the complete system on a vessel of
opportunity (an LCM), and demonstration of the ability of the system to operate under
actual conditions. The system was evaluated both in the San Francisco Bay and off Coal
Oil Point (Santa Barbara) where sorbent materials were dispersed over natural oil slicks.
The system utilizes commercially and readily available equipment which, with minor
modifications, was assembled on-site into available vessels. The system was found to
be very effective in recovering sorbents (straw and polyurethane foam) from the water
surface.
*0il pollution, *0il sorbents, *Conveyor systems
*0il recovery systems, *0il/sorbent recovery
,•1 ••;,-.;, -, 19. Sc-Lurit-; Cii-.ss.
7 3. S. rityC 's.
21. Vo. Of
Pa^es,
':!. P. s
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 2O24O
James D. Sartor 1 URS Research Comoanv
«U.S. GOVERNMENT PRINTING OFFICE:! 973 514-144/295 1-3
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