Carbon storage during biodegradation of municipal solid waste components in laboratory‐scale landfills

The objective of this research was to measure the amount of carbon associated with the major biodegradable components of municipal solid waste (MSW) that remains in long‐term storage after anaerobic decomposition in landfills. Tests were conducted in quadruplicate in 2‐L reactors operated to obtain maximum decomposition. Measured carbon storage factors (CSFs) for grass, leaves, branches, food waste, coated paper, old newsprint, old corrugated containers, office paper, and MSW were 0.32, 0.54, 0.38, 0.08, 0.34, 0.42, 0.26, 0.05, and 0.22 kg C sequestered dry kg −1 , respectively. These values were then used to estimate an overall CSF for MSW that varied from 0.274 to 0.302 kg C sequestered wet kg −1 for waste mixtures that exclude and include recycling, respectively. On the basis of an overall CSF for MSW and data on global MSW generation, global carbon sequestration from MSW burial is estimated to be at least 119 million metric tons per year.