ANCHORAGE (AP) -- Using the same basic process that sterilizes luxury hot tubs, a team of scientists and technicians working for BP have been pumping ozone through ballast water in an Alaska oil tanker to kill hitchhiking organisms.
Three recent experiments conducted aboard the tanker Tonsina in Puget Sound may offer a breakthrough to one of the world's most intractable ecological problems: the threat posed by creatures that travel from one coast to another in ballast water and colonize new habitat when the water is discharged.
''From what I've seen so far, it looks promising,'' said project manager Joel Kopp, an expert in ballast water issues who coordinated studies for the Prince William Sound Regional Citizens' Advisory Council in Valdez. ''I think the testing shows that ozone could be one of the tools that could be effective in treating ballast water. How effective, we'll have to see.''
Ballast water is used to stabilize empty tankers on their back run to an oil port. The water is taken on after oil is delivered and is flushed out before taking on new cargo.
It has been a major cause of catastrophic biological invasions worldwide, causing extinctions and billions of dollars in economic damage. At least 7,000 different species get hauled across the ocean every day inside ships, many in the 2 million gallons of ballast water dumped each hour in U.S. ports, according to an October report on invasive species from the foundation-funded Pew Oceans Commission.
The unique organism-killing prototype, designed by ozone specialist Nutech O3 and installed aboard the double-hulled Tonsina last year, zaps oxygenated air with 10,000 volts of electricity to produce about four pounds of ozone each hour inside the world's largest shipboard ozone generator, according to Kopp and BP officials.
The ozone then can be pumped through four miles of stainless steel pipe into 1,200 stone diffusers scattered among the tanker's 15 segregated ballast tanks. Over a three-to-seven-day voyage from the West Coast to Valdez, the process will theoretically kill all the plankton, bacteria, viruses and other tiny beasties swimming within about 12.6 million gallons of ballast. It would also kill the plankton-sized larval stages of dangerous invasive species like European green crabs.
''If this is effective, it's going to have significant impact on shipping worldwide,'' said Simon Lisiecki, manager of BP's marine business development in Alaska. ''All I can say right now is it looks positive.''
A report will be finished in the next few months, Kopp said. But two 10-hour tests conducted in early November on one 800,000-gallon port ballast tank appeared to kill most of the tiny creatures in the water. Some larger organisms like shore crabs didn't die when suspended in cages.
''We've seen that it does kill plankton and it does kill bacteria,'' Kopp said. ''But at what cost and how effective is it compared with other technologies?''
More testing to meet Coast Guard and scientific review standards could follow early next year. Additional research has been funded with $600,000 in grants from the National Sea Grant Program and the U.S. Fish and Wildlife Service, Kopp said.
If the system ultimately proves practical and economical, BP may decide to install it on three tankers now under construction, said Neil Dunn, president of BP Oil Shipping Co. USA. The project has so far cost BP about $3 million.
It's from these infested West Coast harbors that most Alaska tankers take on ballast to help stabilize their empty return trip to Prince William Sound. During about 550 voyages per year, the tankers deliver an estimated 17 million metric tons of this water to Valdez Arm in what one scientist has likened to a game of ''ecological roulette.''
''That one vector from the West Coast to Alaska is probably the single biggest transfer of ballast water in the United States, and most of that is to Valdez,'' Kopp said. ''If you're going to start somewhere in the treatment of domestic ballast water, this is a big place to start.''
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