The effect on the GHG emissions and energy consumption of MSW management practices on Porto city

Abstract

The present case study was developed for the municipality of Porto, the second largest city of Portugal that has near 300 000 inhabitants. Due to legislative evolution, some changes have been implemented on MSW management practices since 1990 leading to meaningful improvements on energy consumption and greenhouse gases emissions. Two situations were compared: (i) the first one concerns the situation in 1990 where the MSW produced was collected, a meaningful fraction of it was composted and the residual waste dumped; and, (ii) the second situation where the EU legislation on recycling targets for packaging material and diversion of organic waste from landfills was taken into account, including an incineration plant on the management system. Greenhouse gas emissions from these two management scenarios were calculated based on an inventory model developed by White et al (1992). Weighting factors for the different gases based on the recommendations of the Intergovernmental Panel on Climate Change were used to aggregate the emissions values and obtain a simple and comparable result for each situation. Results show the advantage of the 2000 practices both in terms of energy consumption and emissions of gases with greenhouse effect.