Current and future greenhouse gas (GHG) emissions from the management of municipal solid waste in the eThekwini Municipality – South Africa

Abstract

When considering projections of greenhouse gas (GHG) emissions from waste there is a paucity of such studies for municipalities in developing countries and particular in Africa. This study addressed that gap and by taking a life cycle approach, current and projected emissions for the eThekwini Municipality situated in South Africa are calculated. These calculations use country specific emission factors for the different waste management processes and include upstream, downstream and operational GHG emissions. These emission factors are applied to different amounts of waste materials processed though different waste management processes (transported, landfilled, recycled, composed and/or anaerobically digested) and the overall GHG emissions for the system have been calculated. Three scenarios are defined, namely the current situation, the expected situation in 2014 after the closure of one landfill and the projected situation for 2020. In 2012 (considered current situation) the GHG emissions from the entire waste management system in this municipality were in fact net savings of about −1,61,780 tonnes CO2 e (CO2 equivalents). The closure of one of the three local landfill sites in 2014 and the re-directioning of the majority of waste to another landfill site which does not have landfill gas collection and utilisation, will cause an increase of GHG emissions to 294,670 tonnes CO2e. For the year 2020 an increase in recycling can save −2,07,056 tonnes CO2e and the introduction of anaerobic digestion about −157682 tonnes CO2e. However, the introduction of landfill gas collection and utilisation systems for the Buffelsdraai landfill site will result in the highest possible overall GHG savings of −630,867 tonnes CO2. The results presented in this paper show that life cycle based GHG emission factors for waste and their use can support decision-making for municipalities in the local context and aid in optimising integrated waste management systems as to achieve the highest possible GHG savings.