Modified sawdust could be key to tackling oil spills, expert says

Sawdust is an abundant resource in B.C., and a researcher from Washington State University says it could help tackle off-shore oil spills.

Many on British Columbia's South Coast have expressed concerns about the potential of an oil spill after the federal government's recent approval of Kinder Morgan's Trans Mountain pipeline expansion project.

If the project goes through, tanker traffic could increase in the area from five tankers per month to 34.

The federal government has committed funding to a comprehensive marine spill response, but many project opponents have pointed out the ineffectiveness of current oil spill response techniques which include using booms and skimmers to remove oil from the water. 

For example, after the Nathan E. Stewart — a fuel-carrying tug — sunk off the coast of Bella Bella, oil recovery crews were hampered by bad weather and gale force winds which pushed booms out of place.

That's where sawdust shows some promise.

While sawdust can soak up oil, it also typically absorbs a lot of water. That's why George Bonheyo, a senior research scientist and professor at the university, chemically modified sawdust to be water repellant.

"What this does is it renders the sawdust to be incredibly buoyant, so it will float for about four months. It absorbs five times its weight in oil and rejects water. It also rejects the formation of ice," he explained.

Bonheyo said the sawdust can keep oil closer to the surface, allowing it to be collected. It can also enable burning — a rapid way of removing oil from the environment.

"For example, in the BP Deepwater Horizon spill in the Gulf of Mexico, burning was one of the more effective means of removing oil from the environment. A highly efficient burn can remove upwards of 90 per cent of the oil."

Burning is not a perfect way of getting rid of the oil, Bonheyo pointed out, as it releases a lot of carbon into the atmosphere.

"On the other hand, if a storm is coming and the oil is approaching an endangered or sensitive habitat, sometimes burning is the best option to quickly get that oil out of there before it can coat a coastline."

Otherwise, the sawdust can be skimmed and collected. The oil can then be separated, recovered and refined from the sawdust for normal use, he explained.

Challenges remain

Bonheyo said his research has focused on Alaskan North Slope crude oil, and the properties of heavier Albertan bitumen might react differently.

Because his sawdust material is designed to be extremely buoyant, he explained, materials that sink below the surface would require different treatments.

"Bitumen, dilbet, and synbit present some unique challenges for cleanup in aquatic environments because of their density," he said.

"My team and I are developing some new approaches for how to treat bitumen and tarry residues that have sunk, including approaches to treat the residues on the seafloor and approaches to lift the oil back into the water column or back to the surface, but these are currently in the conceptual phase." 

Bonheyo is currently studying whether the product will have any unwanted side effects. He expects it could be ready for use within one to three years.

With files from The Early Edition

To listen to the interview, click on the link labelled Washington state research highlights new ways to fight oil spills