Submerged Oil Recovery for the US Coast Guard

U. S. COAST GUARD RESEARCH AND DEVELOPMENT CENTER
Contract No. HSCG32-10-C-R00003

A REPORT OF TESTING AT OHMSETT LEONARDO, NJ  NOVEMBER 2011
Final Report
OIL STOP DIVISION OF AMERICAN POLLUTION CONTROL CORP
January 23, 2012

Abstract

In November 2011, the Oil Stop Division of AMPOL participated in the physical testing of Phase 2 of its contract with the U.S. Coast Guard Research and Development Center for developing and testing a submerged oil recovery system at the OHMSETT facility in Leonardo, New Jersey. The OSBORS (Oil Stop Bottom Oil Recovery System) completed a battery of tests.  The key component of the OSBORS is the EDDY Pump. This powerful pump can be attached to an Excavator, as it was during these tests, or mounted on a remote controlled submersible vehicle called a Sub Dredge, and used to remove highly viscous submerged oil from the bottom of a lake or ocean.

The system uses a high definition camera to find, monitor, and record action at the head of the pump.  For the OHMSETT tests, three types of highly viscous oil were placed in submerged test trays on the bottom of the OHMSETT Tank. Each tray contained loose sand and various obstacles. The system was able to effectively remove a majority of the oil from each tray in a matter of minutes.  In one instance, the system removed approximately 90 % of the oil in six minutes of pumping time.

Due to the unique tornadic suction created by the EDDY Pump, no visible turbidity or dispersed oil was created near the pump during the tests. Analysis of collected samples confirmed that the pumping operation did not create turbidity or disturb oil into the water. The recovered materials were pumped into phase separator type roll off containers to begin the separation of oil, water, and solids and prepare the recovered water for treatment and subsequent in-situ discharge.

Purpose

The purpose of the tests was to demonstrate the system’s ability to effectively remove highly viscous submerged oil from a variety of simulated bottom conditions, and to receive, handle and separate the high volume of materials generated from the operation.  A specific list of tasks was to be performed and measured in accordance with the contract and the test plan.

1.0 Introduction and Overview

1.1 Description and purpose

There is a widely recognized need for effective technology that can remove sunken oil suspended on the bottom of water bodies.  U.S Coast Guard Research and Development Branch awarded a contract to Oil Stop, a division of AMPOL, to develop and refine such a bottom oil recovery system. Oil Stop created the OSBORS Group, which has a specialized package of equipment designed to remove sunken oil and handle the recovered materials. At the heart of OSBORS is EDDY Pump Corporation’s Sub Dredge. This is a remote controlled vehicle equipped with an EDDY Pump. Additional topside support equipment was added for collecting, separating and disposal of recovered materials. This system was transported to the OHMSETT facility in Leonardo, New Jersey. Dates of the tests were November 17, 18, and 19 of 2011. Weather conditions were typical fall weather for this area. Specific weather and test tank conditions for each of the tests are shown later in this report.

The OSBORS Test Plan was based on addressing design concepts as required by the USCG RDC.  The test plan was set in five segments designed to gather information on each of the design concepts below.

1. Positive identification of heavy oil on the bottom
2. The oil’s location geo-referenced within 5 meters
3. Minimum dispersal of the oil into the water column during removal
4. Real time observation, data and feedback
5. Recovery in various types of sea floor conditions
6. Operate in various salinities and water conditions
7. Able to operate in water to 200 ft deep
8. Low maintenance of system
9. Ease of operation/ minimum training of operators required
10. Durable and easy to decontaminate
11. Equipment not affected by oil
12. Operates in current of up to 1.5 knots
13. Operates in up to 5 ft seas
14. Operates day and night
15. Sets up within one day after arrival
16. Works with highly viscous oil (2,000-100,000 cSt)
17. Includes a suitable decanting system
18. Includes ability to polish decanted water for disposal back into water body
19. System produces minimum impact to benthic organisms through turbidity

(Items 7, 12, and 13 were not addressed in the OHMSETT tests)

The five segments were designed as follows:

Test #              Title                                         Design Concepts

1          Compatibility with Oil Detection       1, 2, 4

2          Oil Removal from Sea Floor               3, 4, 5, 6, 9, 11, 14, 16

3          Mobilization                                        8, 9, 10, 11, 15

4          Maneuverability                                  5, 9, 14, 19

5          Top-side Materials Handling              4, 8, 9, 11, 14, 16, 17, 18

2.0 Methods and Materials

2.1 Set up/trays and contents

For this set of tests, four trays, 10 feet by 20 feet by 1 foot deep, were placed on the bottom of the OHMSETT tank. A base of sand and simulated obstacles, in the form of cinder blocks and stacks of flagstones created the “sea bottom” for the tests. Three types of heavy oil were placed on different types of sand as shown in the following matrix.

Table 1.  Characteristics of Test Trays

Table 2.  Physical Conditions

* Visibility at camera and video monitor

2.2 Technical Approach and Components

As this was a submerged oil recovery operation, the removal of a high volume of water along with the oil was unavoidable and had to be prepared for in the system’s operation. Since the ultimate goal is effective removal of the oil, efficiency, as in terms of oil-to-water ratio in the recovered product was not a quantitative, or qualitative, factor, as it might be with surface oil recovery. The recovered material (oil, water, and solids) was pumped from the trays to one of two collection tanks. A total of 120 feet of transfer hose from the pump to open discharge into the collection tanks was used.  One of the collection tanks (25 cu. Yd.) was an open top phase separator (dewatering tank).  The other was a closed bulk liquid receiving tank (30 cu. Yd.).

It was anticipated that the high energy of the open discharge into the tank would generate a forced aeration of the materials, and there was a real possibility that some of the oil would refloat, at least temporarily. To take advantage of this opportunity, a Rope Mop skimmer was set up on one corner of the open top collection tank to remove the floating oily material from the surface of the tank. A simple “duckbill” surface skimmer was also available in the event the rope mop system could not handle the viscous oil.

The phase separator is equipped with a stainless steel mesh insert and a secondary bottom.  Additionally a 200 micron mesh filter cloth was fixed to the inside of the tank. A water discharge pumping system consisted of a reciprocating diaphragm pump drawing from the secondary bottom of the phase separator and through a dual canister bag filter. Two types of bags were tried during the course of test: a 100 micron solids removal bag, and a 100 micron solid removal filter enhanced with oil collecting polypropylene mesh. From this point, the water was returned to the OHMSETT tank after passing through another oleophilic bag filter attached to the end of the discharge hose. This was also a critical sampling point to demonstrate the system’s ability to discharge water with an acceptable level of oil content.

Since it was not practical to operate the remote-controlled Subdredge in the OHMSETT, the EDDY Pump was housed in a custom frame attached to the arm of a construction grade excavator and operated hydraulically.

The operation of the pump was controlled with foot pedal activation. There was a digital video camera fastened to the frame of the pump and a closed-circuit monitor was installed in the excavator cab so the operator could locate the oil and monitor the progress of the oil recovery operation.

Initially, a pair of wheels was attached to the frame of the pump. The pump was also equipped with a rotating rock shroud to deflect larger rocks and debris from entering the pump intake. After the first oil recovery operation, both of these items were removed when it became apparent that the wheels kept the mouth of the pump too far from the surface, causing the pump to withdraw too much water relative to the volume of oil removed. After removing the rock shroud, a 6-inch length of 4-inch diameter pipe was added to the suction inlet to allow better pinpointing of the oil.

Sample Gathering and Measuring Tools

A zone sampler with a telescoping handle was used to collect samples in the area of the pumping operation.  Samples were gathered to enter base and background turbidity and oil-in-water content, prior to commencement of pumping operations.  A grab sampler (open flask) was used to collect samples from the collection tanks and from the “clean water” discharge.  Portable field analyzers were used for testing turbidity and oil-in-water content samples.  Laboratory equipment and data was also provided by OHMSETT for base data. A complete list of components with brief descriptions is provided in Appendix B.

2.3 Operational Tests.

2.3.1. – Assembly and mobilizing

a. Assembly consisted of attaching the EDDY pump frame to the excavator arm and installing and connecting the camera. The shipping crate holding the EPC components and the EDDY pump was pre-positioned on the ground near the test tank. This operation required two workers (both from EDDY Pump Corporation) and normal hand tools, and was accomplished in less than two (2) hours.

b. Material transfer hoses were connected and secured once the excavator was in position over the trays. Hoses were fitted with standard 8-hole flanges and gaskets. Ratchet straps were used to attach the hoses along the arm of the excavator and the side railing of the test tank. This operation involved four workers, and was accomplished in one (1) hour.

c. Set up of the separation system was performed simultaneously to the above two operations.  Two workers installed the filter cloth liner in the phase separator tank. A forklift was used to place the rope mop skimmer atop the collection tank. (Note: This could have been accomplished manually by separating the mop machine from its oil pan.). The water discharge pump was connected to the collection tank discharge and to the dual canister solids filter via hoses fitted with tool-free Camlock fittings. This operation took approximately 1.5 hours.

d. Altogether, including some adjustments and system testing, the entire system was operational within 5 hours of arrival. Therefore, in response to test point No. 15, Sets up within 12 hours after arrival, the OSBORS, in excavator mode, clearly satisfied this requirement.

2.3.2. Oil Removal

Most of the key points required of the test plan are addressed during oil recovery and subsequent materials handling.  These key points will be noted below in the reporting of operations on each tray.

Tray 9 – November 18, 2011

Tray 9 had three stacks of cinder blocks placed at the edges of the oil. The oil was set in one fairly uniform row diagonally across the tray atop a relatively even 3-inch layer of mason sand.  Ohmsett data reported a 1-inch layer of Sundex (Barite infused) type oil, and a total volume of 35 gallons.  A background sample was gathered within 1 foot above the test tray.  Analysis indicated 1.7 NTUs turbidity and zero oil-in-water content.

Recovery from Tray 9 began at 12:03 pm and continued until approximately 12:10 pm, with an elapsed time of 7 minutes, and an actual pumping duration of 5 minutes. The pump was operated at 1600 RPM, providing a pumping rate of 800 GPM. This was the first tray operation. The EDDY pump was equipped with the wheels on the housing and the rock shroud. As a result of the high volume pump rate and the suction head being raised too high above the oil, a high volume of water was transferred, and the collection tank (6000 gallon capacity) was quickly filled to near maximum level (Measured 5100 gallons). A further result showed that, although only a small percentage of the oil had been removed, the energy at the open discharge into the collection tank did aerate the oil, and it did float on the surface. However, the weighted pulley on the rope mop machine was knocked to its side by the force of the discharge, and the mop machine was not engaged.

The dewatering of the collection tank began. Using a utility pump, the collection tank was drawn down to near empty in 1 hour. None of the surface oil was removed from the collection tank at this time. A sample was grabbed at the open discharge. Turbidity was high because the fine masonry sand was smaller than the 100 micron filters could catch. Oil-in-water was less than 10 ppm.

At 1:55 pm, the oil removal operation was recommenced and continued until 2:20 pm. The pump/excavator operator engaged the pump intermittently while hovering over spots of oil in an attempt to reduce the water intake. The operator was a quick learner and was able to remove nearly all the visible oil from the tray before filling the collection tank. The obstacles did not impede the pump operation or the visibility of operator. The total volume of material removed was 3,100 gallons. Again, as during the first pumping operation, the discharge energy aided in refloating the oil. Measurements of the oil material thickness on the surface of the collection tank indicated a volume of 55 gallons (Tank Volume = 101 gallons per inch). A sample of this floating material was skimmed with the grab sampler for analysis in the OHMSETT lab. Using a centrifuge and testing for Basic Sediment and Water content in the oil, the results were:

Water – 50.6%
Sediment – 2.6%
Oil – 46.8% (or 25.75 gallons oil)

Of course, this volume of 55 gallons is only the refloated oil. Upon draining the phase separator later, an undetermined amount of oil was adhering to the filter cloth inside. Visual observation of the test tray revealed small patches, mainly in scattered droplets, of oil on the tray. It was mutually agreed by observers that 90% of the oil had been removed from the tray.

Basic Data (Tray 9):
Total time oil removal: 32 minutes
Total time pumping: 12 minutes
Total volume pumped: 8,200 gallons
Average volume: 683.3 gallons per minute
Estimated solids: 500 gallons
Estimated oil recovered: 31 gallons
Turbidity level (Pre-pumping) – 1.7 NTUs
Oil-in-water level (pre pumping) – 0 ppm
Turbidity Level (During Pumping) – 1.7 NTUs
Oil-in-water level (During pumping) – 0 ppm
Decanted Volume: 6,590 gallons
Decant Water Oil-in-water – 8 PPM

Tray 10 – November 18, 2011

Tray 10 oil recovery operations started at approximately 3:24 PM and continued intermittently until 3:44 PM.  Two piles of flagstone were located along the edges,of a continuous strip of oil. OHMSETT data indicated there were 60 gallons of Tesoro “Decant” oil that was mixed with 2.5% diesel fuel.  The oil thickness ranged from 6-inches on one end and was gradually thinned to ½-inch on the opposite end.  The pump was set to be operated at 1200 RPM, which provided pumping rate of approximately 800 GPM. 1200 RPM appears to be the lowest rate at which the pump will operate effectively. The wheel kit and rock shroud were still attached to the pump housing.  This tray had 11-inchesof sand.  We intended to do a brief test pump to learn if the wheels would sink into the sand and allow the pump inlet to get nearer the oil.

The underwater viewing windows on the side of the OHMSETT tank allowed a good side view of pump suction head and its relative position to the product. As set up with the wheel kit and the rock shroud attached, the inlet end of the pump was 9-inches“off the ground”. The wheels did sink into the sand and the pump was removing oil but it was obvious the system would be more efficient, at least in these conditions, if the wheels and rock shroud were removed.

The decision was made to cease operations for the day. The plan was to remove the wheels and rock shroud, and add a six-inch extension to the pump inlet. This extension would allow for more precise targeting of oil without concern of the wheel brackets. Recording for Tray 10 operations would officially commence the next day.

Tray 10 – November 19, 2012

The removal of the wheels and rock shroud was accomplished in about one hour. A four-inch diameter steel pipe was located and cut. OHMSETT assisted in welding it to the end of the pump inlet. Stripped tape was fixed to the end of the nozzle to provide a more accurate point of reference to the operator.

Background samples for turbidity and oil-in-water were taken.

The modification to the pump end proved to be a most beneficial adjustment.  The operator could concentrate on targeting the patches of oil, and maneuver the pump more freely without major concern for obstacles.  When obstacles were in the area, the narrow 4-inch tube permitted more precise and complete removal of oil.  The excavator operator quickly mastered the technique of targeting the oil. His experience in sensitive area and contaminated sediment dredging was applicable to the best techniques for oil removal.

The pumping operation spanned a total of 14 minutes.  The pump was stopped and started frequently as the operator strived for efficient removal.  At the commencement of operation we agreed we would try our best to clear the 60 gallons of oil from the tray before the collection tank was filled.  By the time the collection tank was filled, there were only small spots of oil remaining on the tray.  Visual assessment estimated more than 90% of the oil was removed.

The discharge from the recovery operation was pumped into an open top phase separator. Again, the aeration of the discharge allowed an appreciable amount of oil to refloat to the surface. A weir skimming technique using a diaphragm pump and a small duckbill shaped end on the suction hose was used to clear the surface of oily material.  Two 55 gallon drums were filled. The water decanting operation began by drawing from the bottom of the phase separator. A sample was grabbed from the open discharge downstream from the canister filters.  This was later analyzed using the field oil-in-water content analyzer.  Results indicated 8 PPM oil in water.

During the discharge into the OHMSETT tank, it was noted that the discharge stream was colored and obviously contained suspended solids.  This was a result of the micron size of the sand in the test trays being less than the 100 micron filters in the canisters.  At OHMSETT’s request, we ceased discharging into the OHMSETT tank.

Tray 10 – Basic Data
Total time oil removal: 14 minutes
Total time pumping: 8-9 minutes
Total volume pumped: 5,200 gallons
Average volume: 611 gallons per minute
Estimated solids: 1200 gallons
Estimated oil recovered: 55 gallons
Turbidity level (Pre-pumping) – 1.7 NTUs
Oil-in-water level (pre pumping) – 0 ppm
Turbidity Level (During Pumping) – 1.7 NTUs
Oil-in-water level (During pumping) – 0 ppm
Decanted Volume: 900 gallons*
Decant Water Oil-in-water – 8 PPM

* Decanting ceased at request of OHMSETT due to high solids content.

Tray 2 – November 19, 2011

Tray 2 had a 2-inch layer of concrete sand and one rock pile in the center of the tray.  350 gallons of Tesoro oil (uncut with diesel) was evenly distributed over the entire surface of the tray.  The oil thickness was 3.5 to 4-inches. This Tray had been previously worked on by another contractor, and oil had been added to its surface.

The strategy for this tray was to maximize speed of recovery. We directed the operator to make long sweeps of the pump across the tray to recover the oil as quickly as possible. The 10 mph wind caused a ripple on the surface of the pool and visibility was relatively not as good from above. Beneath the surface, there was good visibility.  Pumping began at 9:50 am and ran intermittently until 10:35, with an estimated actual pumping time of 16 minutes during 45 minutes of operation. Discharge from the EDDY pump was diverted to the closed top roll-off tank (Adler). This tank has a capacity of 8,400 gallons. The operator had no problem maneuvering the pump head around the pile of rocks and across the tray. Near the edges of the tray, more caution was required to prevent contact with the wheel brackets. However, removal of oil abutting the tray walls was accomplished.

Pumping was stopped when the Adler tank contained 6,333 gallons of material. Visual analysis of the tray estimated oil had been removed from over 50% of the surface.  The estimated volume of oil removed was 200 gallons. The material in the collection tank was allowed to settle during the midday break. Upon return, the tank was stick gauged and it was determined an estimated 1260 gallons of solids had been discharged into the tank. This is probably a result of the operator’s objective for speed recovery without regard for the amount of solids recovered in the process.

The goal was set at the beginning of the day to operate on two trays by the end of normal work day.  Although, all of the oil could have been removed from Tray 2 with more collection tank capacity, it was agreed that we move to the final tray that contained the heaviest oil.  The Adler tank was decanted into the open top phase separator to make room for the next tray recovery operation.  1400 gallons were decanted from the Adler tank into the open top phase separator.

Tray 2 – Basic Data
Total time oil removal: 45 minutes
Total time pumping: 16 minutes
Total volume pumped: 6,333 gallons
Average volume: 395 gallons per minute
Estimated solids: 1260 gallons
Estimated oil recovered: 200 gallons
Turbidity level (Pre-pumping) – 2.0 NTUs
Oil-in-water level (pre pumping) – 0 ppm
Turbidity Level (During Pumping) – 4.0 NTUs
Oil-in-water level (During pumping) – 0 ppm
Decanted Volume: 1400 gallons*
Decant Water Oil-in-water – Not sampled

*Decanted directly to secondary tank; not overboard

Tray 7 – November 19, 2011

Tray 7 consisted of a 6-inch layer of masonry sand onto which a two feet wide swath of Sundex oil was laid 4-inches thick diagonally across the tray. OHMSETT reported 80 gallons of oil were placed in the tray.  Two sets of obstacles were placed on the edge of the oil on opposite sides.  One end of this tray was very close to the underwater viewing windows of the OHMSETT tank.

Total time of the oil removal operation was 23 minutes. Estimated pumping time was 7 minutes. Total material removed was 3,166 gallons. As this was the fourth tray worked on by the excavator pump operator, it was obvious he was gaining the knowledge and technique for efficient oil removal. He expertly started and stopped the pump to target the oil and reduce the amount solids taken with the oil. He also used the tilt and articulating capability of the excavator arm to smoothly maneuver the pump head along a line of oil that was bordered by the sand. The concrete block obstacles did not hinder the recovery, and oil within an inch of the blocks was effectively removed. Essentially 100% of the oil was removed. It also marked the most efficient recovery operation, as 80 gallons of oil was removed, but only 3,166 gallons of total material was pumped to the collection tank.

As before, decanting of the water was not attempted at the request of OHMSETT.

A sample of the floating oily material was grabbed and analyzed. The results of the BS&W test were: 63.5 % water, 3.0% solids, 33.5% oil.

Tray 7 – Basic Data
Total time oil removal: 23 minutes
Total time pumping: 7 minutes
Total volume pumped: 3,166 gallons
Average volume: 452 gallons per minut
Estimated solids: 360 gallons
Estimated oil recovered: 80 gallons
Turbidity level (Pre-pumping) – 2.0 NTUs
Oil-in-water level (pre pumping) – 0 ppm
Turbidity Level (During Pumping) – 9.0 NTUs*
Oil-in-water level (During pumping) – 0 ppm
Decanted Volume: 0
Decant Water Oil-in-water – Not sampled

* Considerable turbidity released from the pump when the pump was shut off and material drained from the hoses through the pump when it was submerged and pointed down.

3.0 Discussion of the Experiments

The following is a discussion of the OSBORS and each of the stated goals from the Methods and Materials section.

3.1 Test Plan Requirements – Achievements and Lessons Learned

Compatibility with Oil Detection Systems

The Pump’s camera system’s ability to provide real time feedback as a type of video reporting was tested. The closed circuit video camera on the nose of the pump was activated to allow the operator and other viewers visual confirmation of the location of the material to be removed. The camera also aided the operator in determining the rate of removal on an instant basis, as well as where the pump should be vertically and laterally in order to maximize removal efficiency, i.e., the most oil with the least solids and water. The videos provided a visual confirmation of the key results of the tests.

Prior to approaching each of the trays, we studied the data provided by OHMSETT in the form of diagrams illustrating the shape and location of the oil on the tray. Strategy was discussed on the best approach to remove the highest concentrations of oil first.  If similar data were provided by oil detection and imaging technologies, the same approach would be done.

Lessons Learned

• Two cameras are better than one. The operator suggested that if we had two wing cameras focused in on the pumping area, rather than one directly in line, that he could be more precise.
• Lighting will be necessary for real-world operations. We know this going in. However, the clarity of the water in the OHMSETT tank did not require lighting.
• The support vessel for the OSBORS, whether in Sub Dredge or Excavator mode, should have precision GPS instrumentation to target oil located by detection technology.

Oil Removal from Sea Floor

A priority of the tests was to extract oil from a series of Trays from among various types of nearby obstacles. Trays were arranged at the bottom of the OHMSETT Test Tank. These trays contained different types of oil, all with specific gravities greater than the water in the Test Tank. Viscosities ranged from 75,000 to 175,000 centistokes.  High viscosity oils were not a problem for the EDDY pump.  As the EDDY pump is a dredging pump, and is designed to transfer up to 80% solids in slurry, it simply handled the high viscosity oil like it was a solid.  The volume of water being pumped also helped in the transport of the viscous oil through the piping and hoses.

As expected, a large percentage of water, relative to oil and solids, was removed.  Also, the collection tanks used for this test were essentially scale models of the ones that would be used in the field.  Larger tanks can be easily adapted to handle large volumes of oily water by skimming the surface oil, filtering the water, and decanting it back to the water body.

Another aspect of the test was to determine the amount of turbidity generated from the operation. Water samples to detect turbidity were gathered as described above. Results showed that essentially no turbidity was produced by this pumping action. This is a result of the type of sand used and the vortex pumping system, which was specifically designed to not disturb nearby bottom sediments while pumping materials.

It was also required to determine whether oil was being dispersed into the surrounding water. Zone samples were taken in the area of the pump head to determine if the operation was dispersing oil into the water around the operation.  Analysis of these samples indicated that no oil was dispersed during the pumping operation. Visibility was excellent in the Test Tank, both from above and through port holes near the test trays. Visual observation showed there was essentially no redistribution of oil into the surrounding water during pumping.

The OSBORS Pump showed it could operate near vertical walls, rock piles, and vertical obstructions such as concrete blocks. The operator could maneuver the nose of the pump quite near these obstructions. The digital camera worked quite well.

The Tests conducted were in water with a salinity of approximately 15 ppt, which is typical of low salinity sea water. There is no reason the pump system should not operate in any type water, from fresh water to super saline (greater than 35 ppt) conditions, as long as the product is submerged and resting atop the ocean floor.

Lessons Learned

• A bottom sensing probe would be useful.  A simple contact rod that would          activate a light, or emit an audible sound, would aid the operator by providing a signal            that he can engage the pump and target material.  This would help reduce pumping of           free water only.
• A one-way check valve should be installed at a suitable point in the flow line.      When pumping ceased and the pump remained suspended, pointing down, materials still    in the flow line would drain.  This created unnecessary turbidity in the area and could   also allow pumped oil to be released.

Mobilization

All components arrived at the OHMSETT facility on commercial or private truck transportation. A record of each item arriving and being unloaded was recorded. Each component was named appropriately in the inventory. Photos were taken to confirm delivery and condition of each item.

The assembly of the system was performed by five (5) OSBORS team members with occasional assistance from OHMSETT personnel.  The following information was recorded.

• Time for assembly, from arrival until ready for operation: 5 hours
• Number of personnel required for assembly: 5
• Tools required: Standard hand tools and battery operated power tools
• Auxiliary equipment required: Forklift or crane (Excavator was also utilized)
• Overall space required. Assembly: 100 ft. square; Operation: 750 ft. square
• Total Weight of components: 76,200 pounds (Excavator = 54,300 Lbs.)

3.1 Disassembly and Decontamination

The disassembly of the equipment was observed by the team and the Coast Guard observers, but not timed. Items that required decontamination before public transportation included; all hoses, the pump assembly, and pump frame attachments such as wheels. Major items not requiring decontamination included the excavator, including tracks and hydraulics. Cleaning of most components was performed using pressure washers on the wash slab at OHMSETT. The collection tanks were pumped and flushed using contracted vacuum trucks. The hoses required special cleaning to remove the oily residue from inside.  This was performed offsite by the equipment rental contractor.

Maneuverability

The operator of the excavator controlled pump was required to maneuver among the obstacles to remove the fixed amount of highly viscous oil lying on sand in the Trays. The volume of oil, water and solids removed in a measured period of time was recorded.

Using visual guidance, the excavator pump was positioned just above the submerged oil while engaging the pump. The suction head was slowly lowered until maximum oil removal efficiency was achieved. This was verified by the digital video system. The pump head was then maneuvered laterally among the obstacles until the maximum amount of oil was removed, as verified by video camera and external observers who were in verbal communication with the operator. Results showed the OSBORS System maneuvered quite well among and alongside the obstacles.

The pump was observed from above the test tank, and from windows in the side of the tank. A digital video was taken of the entire pumping operation. Of interest was how the pump head moved around the Test Tray sides and the obstacles placed in the trays. The pump head is quite heavy, and can knock down the piles of blocks and flat stones. During actual clean ups, it might be advisable to avoid objects such as coral, but track over larger objects such as stones and boulders. The pump can be operated quite close to sensitive items, such as kelp and benthos, since it does not disturb the area more than a few inches from the head.

As the excavator system is a viable mode of recovery, it was noted that the excavator itself was not complicated to maneuver and operate, even in the tight quarters on the tank’s elevated access road.  It did need to be elevated approximately 4-inches for the cap to clear the safety rails alongside the test tank.  This was easily accomplished using 2-inch thick scaffolding boards.

The following was recorded for the excavator/pump during this operation:

• Length of reach from the front of the drive tracks: 28 Ft.
• Vertical reach: 22 Ft.
• Range of side to side movement (swath arc) – As deployed: 180 Deg. In theory: 360 Deg.
• Hover control: 1-inch
• Angle of Tilt: 160 Deg.

Lessons Learned

• In excavator mode, careful observation and planning are required to avoid pinch points on the discharge hose.

5. Top Side Materials Handling

A series of tests were run regarding the OSBORS’ ability to collect all pumped materials from the Sub dredge, separate these materials into solids, oil, and water, and handle each of these materials with in regard to storage and disposal.

The pumped materials were collected in either a 5,100 gallon Baker Phase Separator or an 8,400 gallon Adler Tank. The Baker tank was open-top and the Adler was closed-top. The Baker tank was gauged in accordance with the vendor’s reported capacity of 101.7 gallons per inch. The Adler tank included a strapping table that assisted in measuring the volume with a pipe and tape measure to determine the volume of materials in the tanks at appropriate times.   The submerged oil was transformed by the pumping process to a water-in-oil mousse that floated on the tanks. This mousse is difficult for most types of skimmers to handle as it does not flow, even when placed on a sloped surface. A Rope Mop skimmer was used to help remove the floating product. The oily material did cling to the rope mop, but the squeegee rollers were not totally effective in removing the oil from the mop. The thick oil would accumulate on the rollers and the rollers would lose friction to grip and propel the mop. The rope mop was not totally ineffective, but the process was slow. Using a simple duck-bill shaped hose attachment through the diaphragm pump proved more expedient. It was evident that not all of the oil was refloated. The water between the floating mousse and the tank bottom contained suspended oil particles. However, since the water was decanted from the bottom of the phase separator, it appeared as though the combination of the filter cloth and the accumulated solids created a filter barrier that trapped and prevented any appreciable oil from getting entrained in the decant water.

This decant water was pumped back into the test tank after running it through a dual canister bag filtration system. Two types of filter bags were used in the canisters. Both were 100 micron filter rated. This water was tested for oil content using a grab sample at the open discharge back to the test tank.

It has been a major goal of the OSBORS to augment the pumping system with top-side treatment components that are readily available in all geographic regions where the system may be deployed.  Collection tanks such as Roll-off boxes, frac tanks, and phase separators are offered by vendors in all coastal areas of the United States.  Similarly, wherever there is oil and gas exploration or petro-chemical activity throughout the world, these types of tools can be sourced and rented.  The same can be said for the dual canister filtration system.  The fact that the system was able to demonstrate the ability to receive the materials, process the decant water, and handle the solids, using locally rented equipment, was a positive event of the testing.

Lessons Learned

• The phase separator is a valuable component.  In a full scale operation, it does not have enough capacity to be the primary, initial material collection tank.  If there were several set up side-by-side, they could be feasible, but the oil recovery operation would have to cease while discharge hoses were moved from a full tank to an empty tank.
• Full size (400-500 Bbl) Frac tanks may be more suitable as the main collection tank. Materials could be transferred to the phase separator for intermittent treatment and preparation for water decanting and surface oil removal.
• The aeration created by the high energy of the discharge did aid in refloating a percentage the oil.  A suitable surface oil skimmer and collection system should be a permanent component of the top side treatment system.
• Open top tanks seem to afford more versatility than closed tanks.  However, this may be an issue in permitting during field operations, particularly water-borne operations, so alternatives to open top tanks should be reviewed and planned for.
• A variety of filter sizes should be available.  Most beach sands are larger than 100 micron, but the sands used in this test were obviously smaller than the mesh size, and hence, the solids were not adequately filtered for discharge.

General Requirements

• Easy to operate and requires minimal training. Any experienced excavator operator can quickly master the techniques required to operate the pump.
• Durability of the Equipment and Ease of Decontamination.  There were no mechanical issues with any of the equipment used in the system.  All components, with the exception of the transfer hoses, were adequately decontaminated using hot water pressure washers.
• Ability to Operate Day and Night.  Night time operation was not specifically tested, but there is no reason to believe that with adequate lighting, the top-side components could not be safely operated.
• Operate with Minimum Impact to Benthic Ecosystem – In excavator mode, the system will have a very minimum impact on the benthic ecosystem.  At most times, even the end of the suction inlet was not in direct contact with the bottom surface.  There is a likelihood that nearby epibenthos and some infauna will be sucked into the powerful pump. These organisms will be destroyed by the powerful pump.  However, relative to a conventional dredging operation with a bucket or cutter head, the OSBORS would be far less impactful.

4.0 Results and Conclusions

The recovery tests resulted in up to 97% of the oil being recovered from each Tray. A considerable volume of water was recovered in all cases. It was obvious to all observers that the entire volume of oil could have been removed from all trays if collection tank capacity had been larger.

Solids handling by the pump was extraordinary. Maneuverability of the unit was operator dependent, but only a minimum amount of training was required to make a new operator adequately skilled in the recovery technique to complete the tests.

Oil and water decanting and free oil removal from the storage tanks were not a total success, but enough knowledge was attained to demonstrate the viability of the system as it was designed for the tests. The main issue observed is that, due to the high volume of materials recovered by the pump, a more fluid and continuous decanting operation needs to be developed to allow for uninterrupted recovery pumping.

In excavator mode, limitations of the system, as tested, included its reach and depth of water that the system could be used in. There are “long stick” excavators that will allow for operation in up to 50 feet water depth. There is no reason to doubt the system will perform as demonstrated in deeper water. The footprint of the components can be operated from a standard deck barge or similar sized floating platform. Use of the EDDY pump with the remote controlled underwater Sub Dredge will resolve most of the reach and depth questions. The Sub Dredge can operate and pump oil from 200 feet depths and can range up to 350 feet away from the umbilical terminal.

5.0 Summary

The testing at OHMSETT proved very valuable in the development of the OSBORS.  Some areas exceeded expectations.  Some aspects answered uncertainties.  Shortcomings were noted, but not too alarming.  The USCG-RDC had set a list of design concepts to be addressed in the testing.  Of the nineteen items on the list, fifteen were able to be addressed, to some degree, during the OHMSETT testing.  It could be justified that some of the items had more critical value than others in the overall evaluation.  If one were to place the most gravity on the system’s ability to remove sunken oil from the environment, first and foremost, then the consensus would be the test was a success.  In the end, the tests provided confidence that the OSBORS is field ready and can be a very viable tool in recovering oil from the sea floor.

Components

1. EDDY Pump

2. CAT 320DD Excavator

3. Hoses – 4-inch tank truck type hose with ANSI flange connections; 3-inch tank truck type suction hose with Camlock fittings; 3-inch PVC discharge hose with Camlock fittings

4. Baker Phase Separator – These units use a disposable filter media (filter cloth) which enhances dewatering efficiency. Box can be cleaned without removing any components or filter panels due to the space between           the support screens and walls/floor.

5. Adler Roll-Off Bulk Tank – Closed Top Mini-Frac Tank

6. Baker – 3-Inch Duplex Bag Filter – Two independent filter housings are skid-mounted and piped such that one filter unit is active while the other is out of service. Inlet and outlet connections are provided on each end of the skid. Used for filtering a wide range of industrial and commercial process fluids, groundwater discharge from construction sites, storm water or urban runoff.

7. Spate 75C Diaphragm Pump – The Spate 75C is a high speed, reciprocating, diaphragm pump

8. Model C-13e Mop skimmer

9. Turner Instruments 500D Portable Oil-in-Water Analyzer – The TD-500D^TM is a dual-channel, handheld fluorometer designed  for quick, easy and reliable measurements of crude oil, fuel oil, lube oil, diesel, some gas condensates and refined hydrocarbons in water or soil. When properly calibrated with a correlation method or a known standard, the TD-500D^TM can be used to measure the hydrocarbon concentrations of water samples in less than 4 minutes.

10. Hand held Turbidity Analyzer – 2100Q Turbidimeter—Compliant with USEPA Method 180.1 design criteria.

11. Samplers and gauging tools

12. Filter Media

13. Kronsberg High Definition Underwater Camera

14. Secondary Containment Pools

15. Dewatering Bags (not used)