Inspect the pipe to see if operation of the pneumatic barrier resuspended sediment in the water (White, 1992)
The findings of these field inspections were very positive. In both reports the divers inspecting the pipe found it to be relatively free of sediment and when the barrier was operated there was no significant suspension of sediment. Additionally the reports show that there was no increase in turbidity. (White, 1992).
The lack of resuspension of any sediment and any increase in turbidity was vital in showing that the Air-Guard system was not causing any negative environmental effects. In the contrary, the tests performed on the dissolved oxygen concentration proved that there was an increase of dissolved oxygen in Cedar Creek.
The dissolved oxygen tests were performed by Stephen Edwards of Environmental Services. In the analyses of the water quality two stations were set-up, one at the barrier and one 700 feet downstream. Ambient water samples were taken and then the Air-Guard system was operated for one hour and forty-five minutes and additional water samples were taken. The samples were taken at the surface, mid-depth, and one foot from the bottom. The results of this report are shown in the table below.
Station Depth Dissolved oxygen
barrier surface 9.9
700 ft. from surface 10.0
barrier mid-depth 6.6
samples after 1.75 hours of Air-Guard operation:
barrier surface 7.9
700 ft. from surface 13.6
barrier mid-depth 10.9
These results show the improved water quality due to the pneumatic barrier. Two significant points are that 700 feet from the barrier the dissolved oxygen concentration is noticeably improved. This is due to the strong upwelling current caused by the Air-Guard system. This current not only transfers the dissolved oxygen along the river but also brings the bottom water to the surface This is advantageous when dissolved oxygen is exceptionally low in the bottom depths. The improved water quality on the bottom of the waterbody will have positive impacts on any biological organisms inhabiting the lower regions of Cedar Creek (White, 1992).
ANALYSIS OF THE PNEUMATIC BARRIER
As has been stated earlier in the report the pneumatic barrier offers significant advantages over the traditional boom in spill containment during transfer operations. The past section on the uses of the pneumatic barrier is useful to show that both municipalities, with the case of Buffalo, as well as moderate sized businesses, with the case of Inland, can benefit from the pneumatic barrier. I will refer back to these examples in my analysis of the pneumatic barrier.
The benefits of the pneumatic barrier are many. They are easier to operate, cost effective, and environmentally beneficial. The ease of operation is due to the relatively labor free deployment. The cost effectiveness is a result of the high costs of boom deployment. And lastly, the increased dissolved oxygen can help restore life to the lower depths of heavily polluted waterbodies.
EASE OF OPERATION
The traditional boom's deployment was briefly described in the METHODS OF OIL SPILL CONTAINMENT section. The boom must be physically strung around a barge and anchored in place by one or two people in a small boat. This method of deployment causes several problems. The first and most serious problem is the risk of hypothermia or death for someone deploying boom in adverse weather conditions. The pneumatic barrier's operation is virtually risk free and does not require anyone to be physically on the water for deployment (White, 1992).
Another disadvantage of the traditional boom is in particularly severe weather. In states were containment booms are required for all transfer operations one may not be able to deploy the boom due to weather and notify the State. The transshipment operation is allowed to continue even without the precautionary boom deployed (personal interview, Santa, N 1993). The pneumatic barrier operation is not weather dependent and if a spill occurred during severe weather one could contain it.
The operation of the pneumatic barrier is virtually "push-button". The compressor must be activated and then the surface current will form entraining any spilled oil. This can all be done in very short time with only one person and is a significant advantage over the time and labor intensive traditional boom.
The cost effectiveness of the pneumatic barrier over the traditional boom is clearly seen on page 9 in the Inland example. In this case the operating and maintenance costs are remarkable in favor of the pneumatic barrier. An annual savings of $ 43,500 is possible. With these tremendous differences in O/M costs the pneumatic barrier will not only pay for itself in one year but will save Inland $ 18,500.
While savings of this magnitude is seen at the medium size level a savings can also be realized on a large level. Ocean and Coastal Consultants Inc. is currently working on an Air-Guard system for Citgo in New Jersey. The system Citgo requires is a tanker containment system that uses 1100 feet of manifold and two 1200 cubic foot per minute compressors. The complete capital cost of this system is not yet known but the compressors alone will be $ 80,000 a piece. Citgo has determined the Air Guard system to be more cost effective (personal interview, White, 1993).
The importance of the Citgo and Inland examples are that they show the feasibility of a pneumatic barrier for entirely different levels of use. Where as Citgo is a global distributor of many petroleum products, Inland is a local distributor of generally heating and industrial oils. The pneumatic barrier has proven itself cost effective at both of those levels.
The tests done in by Steve Edwards of Environmental Services at Inland show the positive effects of the pneumatic barrier. There was initial fear by the State of Connecticut that the pneumatic barrier would cause sediment resuspension, increased turbidity, and increased temperature. These problems would have had an undesirable effect on the biological organisms and were not at all evidenced in the Inland field tests. What Mr. Edwards discovered however, was increased dissolved oxygen concentrations and a more favorable distribution of dissolved oxygen allowing life to return to the bottom of Cedar Creek. See table-2.
The possibility of oxygenating the lower depths of our polluted water is a very exciting prospect. The pneumatic barrier will generally be installed in highly industrialized and therefore polluted harbors. The oxygenating effects of the pneumatic barrier could prove very beneficial to the marine environment.
MODES OF FAILURE OF THE PNEUMATIC BARRIER
The pneumatic barrier has one serious mode of failure that must be considered in a serious analysis and that is in tidal current. When the tidal current exceeds 1.5 fps (feet per second) the oil slick will get to close to the plume of air and become entrained below it. Though this is a drawback of the pneumatic barrier the traditional boom will also fail in tidal current at .98 fps (Doerffer, 1992). Until a more efficient containment method is available for transfer operations it will be difficult to entrain spills when the current exceeds 1.5 fps. Another possible failure is compressor failure. This mode of failure can be virtually eliminated if the compressor is properly maintained or if back-up compressors were kept on hand.
This report has shown in theoretical tests and practical real life examples the advantages offered by the pneumatic barrier. The Buffalo River tests proved that the pneumatic barrier could work as a containment device. And the Inland example shows the advantages offered over the traditional boom for moderate sized terminal operators. Together these examples prove that not only is the pneumatic barrier a viable substitute for traditional boom, but also offers numerous advantages over the traditional boom. pneumatic barrier a viable substitute for traditional boom, but also offers numerous advantages over the traditional boom.
The advantages of the pneumatic barrier over the traditional boom are the ease of operation, cost effectiveness and environmental benefits. These three factors make the pneumatic barrier the choice of the future in oil spill containment at transshipment operations.
I would like to thank Norman Santa, of Inland Fuel Terminals, Inc. and Stan White, of Ocean and Coastal Consultants, Inc., for their time and information.
"Applicability of an Air Barrier For Containment Within a
Waterbody" Ocean and Coastal Consultants, Inc. l992
Doerffer, J W, l 992 OIL SPILL RESPONSE IN THE MARINE
ENVIRONMENT New York Pergamon Press
Frank, Ronald, l970 "Oil Pollution Control on the Buffalo River"
PROCEEDINGS - Joint Conference on Prevention and Control of
Grace, J and Sowyrda, A, l 970 " The Development and Evaluation of a Pneumatic Barrier for Restraining Surface Oils in a River" Water Pollution Control Federation
Santa, John, 1993 - Personal Interview
Santa, Norman, 1993 - Personal Interview
White, Stan, 1993- Personal Interview
White, Stan 1992 "Field Inspection of Manifold and Environmental
Issues Summary Report" unpublished