The Army has almost 500,000 tons of munitions that are too old or unsafe to use. It must store these weapons and eventually destroy them by incineration or open-air burning, which emits high levels of carbon dioxide pollution into the atmosphere.
Pamela Sheehan, an environmental engineer and microbiologist at the Army’s Picatinny Arsenal in New Jersey, has pioneered the first environmentally-friendly method of demilitarizing one of the major items in the nation’s outdated military weapons stockpile, the nitrogen-rich propellant used in M119 howitzer artillery rounds.
Sheehan’s solution is to extract the nitrogen from the propellant and use it to grow algae that will produce ethanol and an oil product that can be refined later into diesel fuel.
The process not only recycles the chemical into a usable fuel, but avoids polluting the environment and has the potential to save the government an estimated $8.7 million in incineration costs if fully implemented.
Officials said the stockpile of this propellant, which ignites and propels the ammunition out of a howitzer cannon, is large enough to fill three Olympic-size swimming pools.
“Pamela Sheehan provided the vision, leadership and technical insight needed to innovate a cost-effective, environmentally sustainable, climate-friendly munitions demilitarization process,” said Johnny Figueroa, chief of the Demil Technologies Branch at Picatinny Arsenal.
Sheehan partnered with an algae company, Algenol Biotech LLC, to test the theory on the artillery round propellant because it’s one of the largest portions of the stockpile.
The technique has not yet been tried on other munitions, but officials said it has the potential to work on other weapons that use nitrogen.
Colleagues said Sheehan is adept at translating complicated scientific ideas into practical solutions, which helped as she made the case for her groundbreaking technique.
“She does a very good job of taking a very technical discussion and bringing it down to a level that nonscientists can understand,” said Joseph Pelino, director of technology for the Army Research, Development and Engineering Command at Picatinny.
“This is a challenge for many of our scientists and engineers. They can talk in technical terms, but can’t convey the essence of the project,” he said
Sheehan’s breakthrough comes at a time when many states have tightened restrictions on burning and incineration because of the pollution. As a result of the high cost of incineration and the environmental concerns, much of the unusable and unstable munitions stockpile has been sitting in storage while the Army has sought a better option.
“We never would have considered this technique unless Pam had pushed it,” said Ross Benjamin, deputy director of the Army Munitions Engineering and Technology Center. “It took a lot of evidence, persistence and negotiation to bring people along.”
Sheehan, who colleagues describe as a mentor to students and other employees, said she was “drawn to the government because of the opportunity to work on interesting problems.” She said getting rid of munitions in a cost-effective and environmentally-friendly way falls into that category, and fits in with the Army’s desire to “reduce its carbon footprint and create a sustainability strategy for the future.”
Sheehan said she sees her job not just as developing this technology for the Army, but making it more widely available. She said South Korea already has shown interest in the idea. “What we are doing here has global implications,” Sheehan said.
Colleagues described Sheehan as enthusiastic and a highly motivated individual who does not rest on her laurels.
She’ll say, “Okay, that was yesterday. I have to continue and do other things,” said Marie Forlini-Felix, chief of staff at the Army Research, Development and Engineering Command. “She will just come up with some other great idea. She’s that person—forward-thinking constantly.”