Anaerobic digestion as a sustainable solution for biosolids management by the Montreal Metropolitan Community

The Quebec Waste Management Policy (1998–2008) is requesting that the municipalities prepare a waste management plan, including a global objective of 60% of these wastes to be diverted from landfill sites by reduction, re-usage, recycling and valorization. Around 5.8 million tons of wastes were generated on the territory of the Montreal Metropolitan Community in 2001 for a population of about 3.5 millions citizens. In this paper, we present different management scenarios in which anaerobic digestion was used as a valorization step, focusing on the energetic value of the methane produced and the reduction in greenhouse gas (GHG) emissions. The four scenarios prepared cover the valorization of the organic fraction of municipal solid wastes, green wastes and excess sludge and showed potential methane generation of 17–140 Mm³ with a GHG reduction of 62,000–500,000 tons of CO₂-equivalents.