News Release

Re-creating the ocean, Temple prof. developing protocols for using oil dispersants

Peer-Reviewed Publication

Temple University

How do you bottle an oceanwave? Temple University civil and environmental engineering assistant professor Dr. Michel C. Boufadel is re-creating the energy of the ocean in his laboratory in an effort to develop new testing guidelines for the Environmental Protection Agency (EPA) that will determine the how effective dispersants are in fighting oil spills in certain sea environments.

“We know that oil spills constitute major environmental problems and that once you have a spill at sea, you want to consider ways to deal with it,” says Boufadel, whose expertise is in oil remediation.

Boufadel says a spill at sea can be cleaned up by skimming, burning or adding dispersants--which are like detergents--to the oil. But, he warns, the environment in which the spill has occurred must be taken into account before a method is chosen.

“What is the sea’s state? Is it violent or calm?” asks Boufadel. “If you have a lot of waves, then skimming or burning the oil is not an option. And in most cases, when you do have a spill, it occurs when a tanker has run aground during a storm.”

In addition, he adds, after a certain period of time, the oil absorbs water through emulsion, making the oil very difficult to burn. Boufadel says that the other option, adding dispersants, helps break the oil into small droplets, which can then be consumed by marine organisms because the oil is organic matter.

But, like detergent in a washing machine, dispersants need agitation in order to work properly, which means you need waves in order to apply them to oil spills, says Boufadel.

“What the EPA is interested in is developing a new protocol to test the effectiveness of dispersants,” he says. “The one currently adopted by the EPA, essentially, consists of putting the oil in a smooth flask that contains water, applying dispersants on the surface, and then shaking the flask on an orbital shaker.

“For example, maybe a certain dispersant works well if the sea is not highly agitated,” he says, “while others may work well if the sea is moderately agitated. So some of them may be better than others to use, depending upon the agitation, or mixing energy, of the sea.”

With the support of an EPA grant and a newly developed flask that contains four baffles, Boufadel is developing new protocols for the EPA that correlate the shaking of the water in the flask with the mixing energy of ocean waves, which will determine the effectiveness of dispersants used to clean up oil spills.

“The challenge for us is, if we shake the water at say 100 rounds-per-minute (rpm), there is some mixing energy taking place,” explains Boufadel. “Now, how does that energy correspond with a certain sea state? How does it correspond to waves that are three-feet high or five-feet high, waves that are breaking or unbreaking?”

For example, he says, if you are shaking the water in the baffled flask at 100 rpm, that could theoretically correspond to the same energy of waves that are three foot high.

Boufadel, who is being assisted in his research by graduate student Vikram Kaku, is measuring the velocity of the water at various levels as it rotates in the baffled flask on an orbital shaker, “because essentially, what creates mixing is how the velocity varies. We’re not putting oil in the water at this stage. This is more about understanding the mixing energy that is being created.”

He says that wave energy has been investigated by others, usually by oceanographers who tend not to look at it from an environmental standpoint. He adds that they will be using new mathematical techniques called multi-fractals to try to quantify the wave energy based on existing studies.

“That is our challenge: to determine how much mixing energy is occurring and then, to do theoretical work to scale up these results to approximate a particular sea state,” he says. Boufadel, who is also researching the effect of waves on the large-scale transport of oil, expects to be able to quantify how much mixing energy is occurring in the flask by the end of this summer, before correlating it with certain wave heights.

“We need to give the EPA something concrete,” he says. “We have to come up with recommendations for the EPA that they can take and say ‘Okay, this is the way the testing will be done.’”

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News Media Contact: Preston M. Moretz, Science Writer, Temple University, 215/204-7476 or pmoretz@temple.edu.


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