Sprinkling of sawdust could soak up Arctic oil spills

It's estimated that the Arctic contains approximately 13 percent of the world's undiscovered oil, and with more oil developers eyeing these deposits as the ice retreats in the Arctic Sea, environmentalists are saying an Arctic oil spill occurring is a matter of when, not if. In a bid to avoid similar fallout to that caused by the 2010 Deepwater Horizon fiasco, researchers and various government agencies have been working to test oil spill technologies that can work in icy waters. Now, scientists from the Pacific Northwest National Laboratory (PNNL) have announced it may be possible to adapt a method used in garages the world over – using sawdust to mop up spills.

Since the Deepwater Horizon incident, we've seen an increased focus on developing new ways to contain and clean up oil spills more efficiently. These range from studying water-repellant plants to create new oil absorbent materials, to creating porous materials that can soak up many times their weight in oil. But here's the thing: the Arctic is a different beast compared to the Gulf of Mexico and what works in warmer climates may not necessarily work in the former's cold waters. There are several reasons for this, not least being the fact that conventional booms lose their effectiveness when ice fragments push the oil below the surface and rough waters cause it to disperse.

"Most of today's oil remediation materials are designed for warm water use," says PNNL microbiologist George Bonheyo. "But as ice retreats in the Arctic Sea, fossil fuel developers are looking north, and we need new oil spill response methods that perform well in extreme conditions."

For Bonheyo and his team, what makes sawdust such an attractive prospect is the fact that it is an environmentally friendly and inexpensive material that can remain buoyant in rough or freezing waters, as well as support in-situ burning. In the worst-case scenario, they can at least be sure that it will not cause further environmental damage even if it fails to contain the spill. To turn sawdust into an oil sponge, they modified it by attaching components of vegetable oil onto its surface so that it would absorb the oil while repelling water. The result is a light, fluffy, bleached powder that can be applied directly on top of an oil slick, soak up to five times its weight in oil and stay afloat for four months.

To evaluate the material's performance in icy waters, the researchers tested it on a contained oil spill at the PNNL's Arctic Simulation lab in Sequim, Washington and found that its water-repellant properties prevented ice from forming on top of it, thus allowing it to soak up the oil and stay afloat so it can either be retrieved or burned.

The researchers are also currently evaluating how well it performs in controlled burns. Early results show that small quantities of the powder were able to enable the combustion of both thin and thick layers of spilled oil. In addition, the team is also experimenting with adding tiny, oil-eating microbes – plentiful in the Gulf of Mexico, not so in the Arctic – to the powder's surface to help the oil break down over time.

At present, the material is still undergoing tests and more will be needed before it can be applied to a real oil slick. Of course, the success of an oil spill response in the Arctic depends on many other factors, such as how soon a response team can get to the scene, as well as the weather and real-time data of the Arctic shoreline – many records are out-of-date and there is little information on seafloor topography, which could not only increase a tanker's chances of running aground but also hinder cleanup efforts.

"The chance of an oil spill in the Arctic is real," says PNNL microbiologist Robert Jeters, who is also part of the project. "We hope materials like our modified sawdust can help if an accident happens."

Bonheyo explains the team's work in the video below.

Source: PNNL