Table 4 shows the activities and emissions of CP2, SP1 and VP1.The CO2-eq released due to bio-oxidation of the organic fraction was around 70% of the total emissions from CP2 in the four years
studied. At SP1, the stabilization of organic waste under aerobic conditions generated more than 50% of the CO2-eq released. Amajor fraction of GHG emission was also derived from electricity consumption and waste transfer to other disposal plants by truck (as shown by activity data in Tables S.6eS.8 in the Supplementary
on-line material). In1 is the plant that has the greatest impact on climate due to combustion of RDF, which is about 45% plastic (Table S.10 in the Supplementary on-line material). In 2011, emissions due to decomposition of biodegradable matter in landfills were lower than before, suggesting that this type of plant can have a progressively
marginal role (Table 1). In fact, only waste from the composting and selection plants went to landfills, together with non-hazardous industrial waste that could not be otherwise disposed of. Table 5 shows the emissions avoided by production of electricity from renewable resources and the net emissions of the eight plants. A smaller amount of waste was sent to landfills, compensating the increase in CO2-eq released by the other disposal plants over
the years. Total emissions from waste disposal plants decreased slightly from 2009 to 2011; the emissions avoided due to local production of electricity increased, producing a significant overall emission reduction.