|
Alaska crude used in oil spill test Chilled saltwater used to simulate Arctic conditions for dispersant test in MMS’s high-tech 2.5 million-gallon tank Jeffrey Gold Associated Press Writer
Gallons of inky Alaska crude oil poured into the shimmering green water, forming a dark cloud on the surface. Seconds later, a chemical was sprayed on the slick.
As 3-foot waves churned the chemical dispersant, the oil began dissolving, and a coffee-colored cloud began drifting below the breakers.
An ecological disaster averted? Not quite.
The action took place in a saltwater test tank about 600 feet long at Earle Naval Weapons Station, a naval base with a view of Sandy Hook Bay off New Jersey and New York City. The 2.5 million-gallon tank has its own wave-making machine to simulate ocean-like conditions.
“If you’re in the oil industry, this is your toy store,” said Dennis J. McCarthy, manager of the Clean Harbors Cooperative in Linden, N.J., an industry-funded group whose boats and personnel respond to spills on New Jersey waterways lined by refineries and oil terminals.
Since 1973, the tank has been used to test the effectiveness of chemicals in cleaning up the ocean after an oil spill. The tank also allows researchers to test the booms, skimmers and dispersants that are used when an oil spill occurs.
Number of big spills down before 1989 While the number of big oil spills was falling even before safety improvements that came after the 1989 Exxon Valdez disaster, millions of gallons of oil are spilled into the ocean each year.
“This tank is probably the world’s best opportunity for simulating ocean conditions,” said Alan A. Allen, an oil spill consultant with 40 years of experience, including work on the Exxon Valdez cleanup.
McCarthy and Allen were among about 60 spill scientists and experts from five nations who gathered at the tank on a recent brisk day to observe a cold-water test of a chemical that breaks an oil spill into droplets about one-thousandth of an inch wide. The drops sink into the water, where naturally occurring organisms can feed on them.
The official name of the tank is the Oil and Hazardous Materials Simulated Environmental Test Tank. It’s better known by its initials, Ohmsett, and is part of the U.S. Minerals Management Service.
Oceanographer Joseph V. Mullin, who manages the agency’s oil spill response research, said the tank allows researchers and responders such as Coast Guard personnel to work with oil, not the substitutes that are used in domestic open-water tests.
“It’s not dyed water; it’s not popcorn,” Mullin said. “It’s the real thing.” The United States is among many countries that do not allow testing in open water with oil.
The tank was used last year to test a new design for a skimmer that could remove more oil from the water than traditional models.
The cylinder-shaped skimmer rotates as it’s dragged through a slick. Oil clings to its surface and is removed by a scraper. The new skimmer, featuring grooves on its rotating drum, is to be patented by the University of California, Santa Barbara, said one of the developers, Arturo A. Keller.
The device worked in the testing tank, but some ocean conditions, such as choppy water, couldn’t be reproduced, said Keller, a UCSB professor. “Because it’s a controlled environment, certain things are not the same as you would have in the ocean,” he said in an interview from California.
Tank kept at 31 degrees F for Alaska The tank has a chiller the size of a tractor-trailer that kept the ocean-like water at 31 degrees Fahrenheit for the test, which was requested by the Alaska office of the Minerals Management Service to determine how the chemical worked under Arctic conditions. The agency is currently has Beaufort Sea acreage under lease off northern Alaska and is planning lease sales for the sdjacent Chukchi Sea.
Observers said the chemical used in the test, Corexit 9500, appeared to do the job, although not all embraced the practice of using chemicals to fight oil spills.
“We really support the mechanical recovery process first,” such as skimmers and booms, said a visitor from Alaska, Joe Banta, project manager of the Prince William Sound Regional Citizens’ Advisory Council, a nonprofit group formed after the Exxon Valdez spill to promote environmentally safe oil industry operations.
John S. French, a council board member, said it was not yet known whether the chemicals used to break up oil spills do more harm than good.
Corexit maker Nalco Energy Services, of Sugar Land, Texas, said responders must weigh whether dispersants are the best option.
“The decision to use or not use dispersants involves environmental trade-offs; every oil spill incident is unique,” Nalco spokesman Charlie Pajor said in an e-mail.
He cited a 1989 report by the National Research Council that found the “overall ecological impact of oil will likely be reduced by dispersion.”
Many at the recent Ohmsett tests supported the idea that booms, skimmers, dispersants and burning all have roles in spill response arsenals.
Dispersants supplement mechanical methods Chemical dispersants can supplement the mechanical methods, which are not as effective in high waves or faster currents, said Per S. Daling, a scientist at Sintef, the Norwegian research company.
While chemicals can be applied quickly to a wide area by plane or ship, they are less useful with heavier petroleum products, such as fuel oil, and must be applied before the oil becomes too weathered, experts say.
The Alaska crude used in last month’s test was treated so that it had the characteristics of oil that had been in the sea for 30 minutes.
Burning is best used when there is a lot of oil in a small area, said Allen, the consultant. It is corralled with booms and set afire, but must be done before the oil has become too mixed with water, he said.
“Burning is the only technique that will get rid of a lot of oil fast,” Allen said, and is an option when the damage to the sea and beaches would be more severe than the pollution from burning.
Another option for cleanup is biological agents, which are nutrients used to increase the number of oil-eating organisms. They can be best used in shallow, marshy areas in which booms and dispersants wouldn’t do the job, Allen said.
Biological agents are not tested at Ohmsett because they would be killed by chlorine added to the water to keep it clear for underwater videotaping and photographing, Mullin said.
| 