COMPARISON OF COLLECTION SCHEMES OF MUNICIPAL SOLID WASTE METALLIC FRACTION: THE IMPACTS ON GLOBAL WARMING POTENTIAL FOR CASE OF HELSINKI METROPOLITAN AREA, FINLAND

摘要

The paper describes an investigation of the greenhouse has (GHG) emissions of different practices to collect metal packaging waste in the Helsinki Metropolitan Area, Finland. In order to locate the carbon reduction potential of separate collection of the metallic fraction of municipal solid waste, we carried out a carbon footprint analysis using Life Cycle Assessment on six different waste management scenarios. Four of these scenarios were residential property scenarios, where collection was organized from different sizes of residential properties and regional collections points. In one of scenarios, collection was organized only using regional collection points. In addition, a zero-scenario was investigated, where all the metals are separated from the bottom ash municipal waste incineration. All separate collection scenarios include collection of metals from incineration plant's bottom ash. The modelled system consisted of a waste collection system, transportation, and different waste management alternatives, including on-site separation, separation at the waste management facility as well as metallurgical recovery of separated scrap. The results show that recycling at residential properties is the environmentally most preferable option in terms of GHG emissions. In addition, the zero-scenario, where no metal packaging waste fraction was collected separately, showed clearly higher global warming potential compared to all other scenarios. The results also show that recycling using regional collection points produces considerably less GHG benefits than recycling from residential properties.