If all of the municipal solid waste (MSW) that is currently put into landfills each year in the US were diverted to waste-to-energy (WTE) power plants, it could generate enough electricity to supply 12 percent of the US total, according to a study conducted by the Earth Engineering Center (EEC) of Columbia University.
According to the study, this shift also could reduce greenhouse gas emissions by at least 123 million tons of carbon dioxide equivalents per year.
2014 Energy and Economic Value of Municipal Solid Waste (MSW), including and Non-recycled Plastics (NRP), Currently Landfilled in the Fifty States, found that the recovery of resources from waste, and hence, diverted from landfill, in the US increased between 2008 and 2011. The recycling of materials from MSW improved by 18.5 million tons, and the tonnage of materials processed by WTE facilities grew by 3.8 million tons during this period.
The study’s authors noted that, while some individual states have invested in infrastructure to boost recycling and energy recovery from MSW — Connecticut, Maine, Massachusetts, Minnesota and New Hampshire topped the list — overall, European countries have set a much higher bar.
Sponsored by the American Chemistry Council (ACC), the study is based on data obtained in Columbia University’s 2014 Survey of Waste Management in the US, which looked at waste management statistics during 2011, and from MSW characterization studies in several states.
Engineers at the Earth Engineering Center also calculated the quantity of non-recycled plastics — a subset of MSW that remains after plastics that can be economically recycled have been extracted — available for energy conversion. This latest study expands on an earlier EEC study (published in 2011 and based on data from 2008) by including (in addition to plastics in MSW) plastics that are not counted by the US Environmental Protection Agency as MSW but that are disposed in landfill, such as construction demolition debris and auto shredder residue.
According to the study’s authors, plastics represent 11 percent of the total US waste stream. The total recovery rate for plastics, which includes both recycling and energy recovery, increased from 14.3 percent in 2008 to 16.6 percent in 2011. The recycling rate for plastics increased by 21 percent between 2008 and 2011 to reach nearly 2.7 million tons. The study also found that if all non-recycled plastics in the US were converted to energy through facilities that use modern plastics-to-oil technologies, they could produce nearly 6 billion gallons of gasoline.
New York City will expand a pilot food-waste-to-energy program this fall. The city expects the program to avoid about 90,000 metric tons of CO2.