Is “poop, scoop, reboot” the new “reduce, reuse, recycle?” Erik Coats, associate professor of civil engineering at the University of Idaho, thinks so: He’s making biodegradable plastic from cow manure. 

Coats says that unlike other biomass-related energy sources (including burning firewood for heat or converting corn to ethanol), sourcing energy from manure doesn’t force us to choose between fuel and eating. He uses an anaerobic digester to convert manure to a methane-rich biogas, which can be burned in an engine generator to produce electricity. And his research group at the University of Idaho is currently testing a technology that coverts manure into a biodegradable plastic, thanks to the Idaho Dairymen’s Association and several other like-minded organizations that helped to fund these efforts.

“Our process uses the unique capabilities of naturally-occurring bacteria to ferment manure and then convert the fermentation products to a plastic known as polyhydroxyalkanoate, or PHA,” he says. “PHA is similar to conventional petroleum-based plastics, including polyethylene and polypropylene. But in contrast to these petro-plastics, PHA is biodegradable and can be biologically produced from otherwise unwanted organic waste.”

This plastic can be used in single-use packaging materials, planting pots for the nursery industry and plastic bottles, he notes.

“Moreover, with PHA selling at a premium, significant economic return could be generated from dairy manure beyond electricity,” he adds. 

His group has constructed a mobile pilot-scale system and begun testing at full-scale dairies this year. Pending success of these trials, they are optimistic that the technology can be deployed at full-scale dairies in three to five years, Coats says.