A new research at North Carolina State University (NCSU) in US has found that biodegradable plastics used to make packaging can release large amounts of methane gas when they decay fast in landfills.
NCSU doctoral student James Levis, leading the research said that methane is one of the most problematic greenhouse gases, able to trap much more heat than carbon dioxide and a major contributor to global warming.
Biodegradable plastics are commonly used to make yard-waste bags and disposable drink cups that are designed to compostable.
Levis said in a well-managed compost system, biodegradable plastics don't release much methane, instead will give off mostly carbon dioxide and water as long as oxygen is present.
According to the study, but without oxygen, biodegradable plastics are decomposed by bacteria that give off methane.
The study said that speedy decay of biodegradable plastics creates difficult for landfill operators who try to capture methane from decomposing garbage to prevent it from becoming escaping into the atmosphere.
Landfill operators usually can't start capturing methane until two to five years after the landfill starts filling with garbage, by that time methane escapes into atmosphere.
The research found that if biodegradable plastics were designed to decay more slowly in landfills, operators will be able to capture more of it for fuel.
