Greenhouse gas emission factors for recycling of source-segregated waste materials

A key challenge for the waste management sector is to maximise resource efficiency whilst simultaneously reducing its greenhouse gas (GHG) emissions. For stakeholders to better understand the GHG impacts of their waste management activities and identify emissions reduction opportunities, they need to be able to quantify the GHG impacts of material recycling. Whilst previous studies have been undertaken to develop GHG emission factors (EF) for materials recycling, they are generally insufficient to support decision-making due to a lack of transparency or comprehensiveness in the range of materials considered. In this study, we present for the first time a comprehensive, scientifically robust, fully transparent, and clearly documented series of GHG EFs for the recycling of a wide range of source-segregated materials. EFs were derived from a series of partial life cycle assessments (LCA) performed as far as possible in accordance with the ISO 14040 standard. With the exceptions of soil, plasterboard, and paint, the recycling of source-segregated materials resulted in net GHG savings. The majority of calculated GHG EFs were within the range of data presented in the literature. The quality of secondary data used was assessed, with the results highlighting the dearth of high quality life cycle inventory (LCI) data on material reprocessing and primary production currently available. Overall, the results highlight the important contribution that effective source-segregated materials recycling can have in reducing the GHG impacts of waste management.