Environmentally Correct Fungus : NEXT L.A. / A look at issues, people and ideas helping to shape the emerging metropolis

About the time the end of the Cold War made ballistic missiles obsolete, Teh Fu Yen thought of a creative way to safely dispose of volatile stores of solid rocket fuel.

He uses live bacteria and white rot fungus to gobble up and digest it.

Yen, a professor of environmental and civil engineering at USC, and a team of graduate students have developed a process that uses nitrogen-hungry microbes to break down fuel into largely harmless substances.

Disposing of solid rocket fuel is a troublesome and hazardous endeavor for the military and for industry. Traditional methods of disposal, such as incineration or burial, pose serious risks of toxicity, pollution and explosion.

An explosion last year that killed two physicists at a Rocketdyne laboratory near Chatsworth may have been the result of disposal operations. The company says it was an experiment gone awry, but state investigators allege that the explosion occurred during the improper disposal of waste material.

“Most processes for hazardous waste disposal are very harsh,” Yen said. “Environmental damage is severe using high temperatures and there can be explosions if it is not done carefully.”

He describes the new method, which uses microbes to outwit the fuel’s complex chemistry, as economical and environmentally sound. “It is a mild process, carried out at room temperature or even below,” Yen said.

After initial treatment to break up the polymer binders that add rigidity to the fuel, a fuel-eating fungus is introduced to oxidize the material. That is followed by anaerobic bacteria that further degrade the propellant into easily disposable components such as ammonia and methane.

With the process worked out, Yen sees the next step as a transfer of technology developed at the university to industry.

“We are talking with some states with aerospace companies that handle propellants,” he said.

Yen said the same process, somewhat modified, could be applied to help break down and process another form of waste--automobile tires.

“It’s the same principle,” he said.