Energies (Mar 2018)
Environmental Analysis of Waste-to-Energy—A Portuguese Case Study
Abstract
Environmental evaluation of the waste treatment processes for the area of Greater Porto (Portugal) is presented for the year 2015. The raw data for the energy recovery plant (ERP) provided by the waste management entity were modelled into nine environmental impact categories, resorting to a life cycle assessment dedicated software (GaBi) for the treatment of 1 tonne of residues. Also, a sensitivity analysis was conducted for five scenarios in order to verify the assessment quality. Results were compared to two European average situations (typical incineration plant and sanitary landfill with no waste pre-treatment), which showed that these facilities perform better or at the same level as the average European situation, mostly due to the high efficiency observed at the ERP and to the electricity production in the incineration process. A detailed analysis concluded that these helped to mitigate the environmental impacts caused by some of the processes involved in the waste-to-energy technology (landfill showing the harder impacts), by saving material resources as well as avoiding emissions to fresh water and air. The overall performance of the energy recovery plant was relevant, 1 tonne of waste saving up to 1.3 million kg of resources and materials. Regarding the environmental indicators, enhanced results were achieved especially for the global warming potential (−171 kgCO2-eq.), eutrophication potential (−39 × 10−3 kgPO4-eq.) and terrestrial ecotoxicity potential (−59 × 10−3 kgDCB-eq.) categories. This work was the first to characterize this Portuguese incineration plant according to the used methodology, supporting the necessary follow-up required by legal frameworks proposed by European Union (EU), once this facility serves a wide populational zone and therefore is representative of the current waste management tendency in the country. LCA (life cycle assessment) was confirmed as a suitable and reliable approach to evaluate the environmental impacts of the waste management scenarios, acting as a functional tool that helps decision-makers to proceed accordingly.
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