Now hear this! Sound waves may scuttle scum from ocean vessels

The stubborn barnacles, algae, and microorganisms that cause problems by attaching themselves to ships may one day have an new enemy: sound waves.

A Mississippi State professor believes that acoustic energy--sound waves--can encourage organisms to keep moving instead of settling in and fouling complex and expensive equipment.

Dr. Michael Mazzola, a professor of electrical and computer engineering, has been awarded a three-year Young Investigator grant from the Office of Naval Research to test his theory. He is one of only 33 investigators in the nation selected this year for the award, which provides $75,000 annually.

The problem is called biofouling. It's especially significant in the intake valves of ships, which must take in huge amounts of water to cool machinery. Electric power plants, which also use thousands of gallons of water for cooling, face similar problems.

"Algae and other microorganisms attack the machinery and reduce performance," Mazzola explained. "Speed and efficiency suffer."

Traditionally, chemicals have been used to control biofouling, but they can damage equipment, and there is growing concern about their environmental safety.

Mazzola and co-investigator Michael G. Grothaus, now of the Southwest Research Institute in San Antonio, Texas, last year conducted field tests to see if there were safer options.

Mazzola and Grothaus wanted to know if acoustic energy would be an effective non-chemical solution to biofouling.

"There had been tests using ultrasound, but that could potentially damage the piping system," Mazzola said. "Ultrasound uses a constant wave of sound; we believed that a low-power pulsed surge might reduce the problem without damage to pipes or to the environment."

They set up a controlled experiment, giving organisms a chance to grow undisturbed in a length of pipe. In another pipe, they applied a 25-watt power source every two seconds to generate acoustic energy. The treated pipe stayed free of organisms.

"We were encouraged by the results, Mazzola said. The process is environmentally safe. Organisms are not destroyed; they just keep moving."

The researchers will conduct three years of field experiments to refine and test the process for practical benefits.