"Biodegradable materials, such as disposable cups and utensils, are broken down in landfills by microorganisms that then produce methane," said Dr. Morton Barlaz, professor and head of NC State's Department of Civil, Construction, and Environmental Engineering.
"Methane can be a valuable energy source when captured, but is a potent greenhouse gas when released into the atmosphere," he added.
According to the estimates of the U.S. Environmental Protection Agency (EPA), only about 35 pc of municipal solid waste goes to landfills that capture methane for energy use.
Another 34 pc of landfills capture methane and burn it off on-site, while 31 pc allow the methane to escape.
"In other words, biodegradable products are not necessarily more environmentally friendly when disposed in landfills," explained Barlaz.
Bringing the problem of methane collection from landfills to the forefront, researchers say that if materials break down and release methane quickly, much of that will likely be emitted before the collection technology is installed.
This means less potential fuel for energy use, and more greenhouse gas emissions.
Hence, researchers advocate that a slower rate of biodegradation is actually more environmentally friendly, because the bulk of the methane production will occur after the methane collection system is in place.
The study is published online in the journal Environmental Science and Technology.