According to 2010 EPA data, per capita generation of municipal solid waste has leveled off since 1990 at about 4.5 pounds per person per day, which could be attributed to the increased volume of solid waste recycled that has more than doubled over the same period. Food waste is now identified as the single largest component of municipal solid waste, and, aside from land-use issues related to landfills, there is growing concern over the global warming potential associated with the methane gas it generates, which is a far more potent greenhouse gas than CO2.
According to an independent life-cycle assessment (LCA) of options commissioned in 2011 by InSinkErator and conducted by PE International, food waste disposers that pulverize food scraps and send the slurry to wastewater treatment plants always have a smaller carbon footprint than disposing food waste in a landfill, even in landfills with 100% gas capture. This performance is further enhanced when disposers feed into advanced wastewater treatment systems that can convert food waste into energy through anaerobic digestion, or turn it into fertilizer.
The LCA, which followed ISO 14040 criteria, studied 12 scenarios for disposal, including eight wastewater treatment options, one waste-to-energy option, two landfill pathways, and one composting scenario. The study considered five environmental indicators: primary energy demand, global warming potential (carbon footprint), acidification potential (air pollution), eutrophication potential (water pollution), and smog potential. Go to www.insinkerator.com to see the full report and results.