OIL SPILL BURN TEST SLATED OFF E. CANADA

A major crude oil spill test burn is scheduled to get under way off Newfoundland in early August.

The experimental burn will be the first controlled burn of crude oil in open sea to record the effects of burning oil emissions on air and water quality. A group of 25 government agencies and industry associations led by Environment Canada (EC) will conduct the test burn. The 1 day burn is slated to take place 40 km east of St. John's, Newf., under favorable weather conditions sometime during Aug. 5-15.

RATIONALE

The test is expected to generate data needed to help serve as a yardstick for determining when to resort to burning in accidental oil spills. Involved are oil spill specialists from the U.S., U.K., Norway, France, Sweden, Finland, and the Baltic republics of the former U.S.S.R.

EC Project Manager Merv Fingas noted, "Extensive tests have shown that emissions from controlled burns do not pose risks to environmental health, and now we will see if this is also the case at sea."

EC Emergencies Science Coordinator Greg Halley contends, "Burning oil enables you to take advantage of the window of opportunity you may have in the first days of the spill. You could have the majority of the oil burned before weather conditions deteriorate.

"Mobilizing skimmers and storage containers for mechanical recovery is much more complicated and time consuming than deploying a fire resistant boom. That's why burning oil is such an attractive option. It eliminates delays and removes the oil very efficiently.

Halley does not expect burning to replace the traditional boom and skimmer approach because burning is feasible only in open sea or near uninhabited land. It simply offers another option for oil spill response, he noted.

TEST DETAILS

Once wind, waves, and ocean currents fall within EC safety thresholds, a heavy duty boom will be laid to serve as a backup containment and recovery system for the spilled oil.

A boom to contain the burning slick will be laid 150 m ahead of the backup boom. Then a Canadian Coast Guard (CCG) offshore supply vessel will begin discharging Alberta sweet crude into the fire boom.

The vessel will maintain a speed of about 0.5 knots to maintain oil thickness at the 2-3 mm level required to sustain combustion on the water. Once 10% of the oil has been released into the boom, a Helitorch will ignite the fire, and the oil discharge will continue until the volume reaches a total of 265 bbl. The burn is expected to last 45-60 min. A second identical burn will occur, if weather permits and once all instruments have been checked and reset. Cleanup of remaining oil traces with absorbent pads and skimmers will follow the second burn.

EMISSIONS SAMPLING

During the test burn, two remote control sampling boats will follow the boom, each equipped with 40 measuring instruments. Behind them, a blimp tethered to a floating platform and operated by the U.S. National Institute of Standards and Technology will be positioned in the resulting smoke plume to sample soot concentrations and carbon compounds.

Another vessel positioned 500 m downwind from the fire will sample particulate size, polynuclear aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), metals, carbonyls, carbon dioxide, carbon monoxide, sulfur dioxide, and nitrogen oxides.

The U.S. Environmental Protection Agency will send a remotely operated underwater vehicle directly below the slick to videotape the burn and record water temperatures.

EC remote controlled helicopters will fly directly above the burning oil to sample air emissions from the fire. Wide samples extracted from rotor blades will be used to indicate PAH concentrations in the soot.

Unlike low temperature incineration, which produces PAHS, the test fire, burning at about 800 C., is expected to destroy most PAHs present in the original oil.

Instruments will measure soot, particle analysis, plume trajectory, heat release rates, oil residue, and water column temperature, chemistry, and biology.

ENVIRONMENTAL MITIGATION STEPS

Because the oil in the boom will be maintained at the thinnest possible level needed to sustain a fire, and because it will be present less than 6 hr, the oil is not expected to penetrate below the top 1/2 m of the water column.

The burn is not expected to affect most commercial fish in the region because they are primarily bottom dwellers, and most fish eggs and larvae don't occur in the region in August.

Because of the limited scope of the test, the burn is not expected to significantly affect seabirds or mammals.

TEST BURN COMPARISONS

One of the first oil burning experiments was conducted in 1967, when the Torry Canyon tanker ran aground off England, spilling almost 700,000 bbl of crude into the ocean.

Using bombs, rockets, and other incendiaries, that effort failed because of a lack of technology to contain the oil, EC said.

That led to development of fire resistant booms and subsequent successful 24 hr burns in laboratory tanks in the mid-1980s.

In the first open water test burn, 12 bbl of crude burned in 30 min off Norway in 1988, leaving only a 5% residue.

A test burn at the site of the Exxon Valdez oil spill off Alaska in 1989 involved 400-800 bbl of North Slope crude that burned in only 75 min. It left an easily recovered, stiff residue of about 7 bbl, or the equivalent burn-off of 98% of the oil. Some officials have estimated an emergency oil burn response to the Exxon Valdez spill would have eliminated as much as 50% of the oil in just 2 hr, EC said.

EC expects 98% of the oil discharged in the Newfoundland test will burn off, leaving about 8 bbl of residue after each burn. The residual oil will be reignited after the first burn. After the second test burn, the resulting tar will be collected in fishnets and shovels for incineration on land.

Vice Project Manager Nick Vanderkooy, on loan from Canadian Marine Drilling Ltd., Calgary, concedes burn efficiencies probably will fall in real spills, notably with unfavorable weather and the possibility a slick might not be fully contained.

"It may drop to 50%, but you're still doing a heck of a lot better than you could with mechanical recovery," he said.

Vanderkooy noted an average of 10-15% of spilled oil typically is recovered using mechanical means.

Also participating in the test project management team with EC and EPA are CCG, U.S. Coast Guard, U.S. Minerals Management Service, U.S. Marine Spill Response Corp., American Petroleum Institute, Canadian Association of Petroleum Producers, and 3M Ceramics.