Doctoral thesis- "Potential savings of resources and greenhouse gas emissions from waste management: a case study of Spain in a global economy"
15th July 2014
Sala de graus – Facultat de Ciències. UAB (Bellaterra, Cerdanyola del Vallès)
On the 15th July 2014 the PhD candidate Eva Sevigné Itoiz from the research group of Sostenipra and under the supervision of the PhD Joan Rieradevall, the PhD Xavier Gabarrell and the PhD Carles M. Gasol defended her doctoral thesis. The thesis provides information on the benefits of recycling and the impact of recovered materials which are internationally traded in different financial markets. The results of the thesis can be applied to define policies for waste management at national and international as well as for application in carbon footprint calculations corporate level.
Summary of the thesis:
Our societies need solutions to reduce resource consumption as well as greenhouse gas (GHG) emissions. Identifying waste as a valuable resource can help reduce resource consumption and consequently GHG emissions. Therefore, focus has originally been placed on recovery and recycling. However, waste managers and researchers have recently highlighted the importance of wastes traded in global markets. This global perspective could affect the savings of GHG emissions attributed to recycling. Thus, the goal of this thesis is firstly to calculate and evaluate the GHG emissions from municipal solid waste (MSW) management in Spain. Secondly a special focus is put on the GHG emissions of recycling considering the market and the international trade, specifically for waste paper, aluminium old scrap and plastic waste. A new tool called CO2ZW®, consequential life cycle assessment (CLCA) and material flow analysis (MFA) were applied for the GHG and resource assessments.
The application of the CO2ZW® to evaluate the MSW management confirmed that there is a high potential for climate change mitigation in Spain through the increase of material recovery along with reducing disposal to landfills. The application of MFA showed that there is a considerable accumulation of paper, aluminium and plastics products which in coming years will become waste but the increase in waste supply will probably be exported. Moreover, under the assumption that recycling avoids raw material production, it was also determined that recycling avoids GHG emissions. However, waste can be recycled in Spain or abroad, and recycling can substituted global or Spanish raw material production. The GHG emissions varied in each case. The most competitive global productions of virgin pulp, primary aluminium and virgin plastic were identified as the base scenarios under CLCA. The Spanish national productions were assessed as alternative scenarios. Results showed that the most competitive processes generate more GHG emissions as they are more inefficient and they are often located in countries with high hard coal content in their electricity mixes. Therefore, if these processes are avoided by recycling, more GHG emissions are mitigated than if the Spanish processes are avoided. In addition, increasing the export of waste decreases the GHG benefits for all scenarios evaluated except for the aluminium old scrap export.
The results not only help researchers to evaluate the GHG emissions from waste management but also can be used by producers, waste managers and waste politicians to evaluate and propose the best strategy to reduce the resource consumption and the GHG emissions.
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