Composting is popular as a way to keep solid waste out of landfills and many people turn much of their kitchen waste into rich soil amendments. Cities and towns across the country have composting programs that collect waste from residents to produce large quantities of compost rather than adding the waste to landfills. A new study from North Carolina State University looked into the environmental benefits of actually using compost at landfills.
Most municipal composting programs require that the compost they produce gets used “beneficially”. The new research shows that using compost as an alternative daily cover at landfills is competitive and often superior to the use of compost as a soil amendment in terms of its environmental benefits.
Landfills apply a layer of daily cover to reduce odors, reduce windblown debris, and keep vermin out of landfill waste. Federal regulations require six inches of soil as a daily cover.
Compost from food waste in particular is not always suitable for soil amendment in gardens and agricultural fields because it often contains broken glass and other contaminants.
The North Carolina State study looked at the environmental impact of using compost as daily cover in landfills compared with its use as a soil amendment. They looked at global warming potential, acidification potential, eutrophication (which is the amount of nutrients released to ground and surface water), cumulative energy demand, and the depletion of resources.
The study concluded that using compost as landfill daily cover is environmentally superior with regard to eutrophication, acidification, and global warming potential. On the other hand, soil amendment was better in terms of resource depletion and cumulative energy demand.
Photo, posted April 22, 2008, courtesy of Alachua County via Flickr.