Using life cycle assessment to compare efficiency and environmental impacts of different waste to energy options for Sao Paulo’s municipal solid waste

The present study quantified the feasibility of implementing alternative and complementary technologies for treatment and final disposal of the MSW of São Paulo to generate electricity with consideration of potential environmental impacts using life cycle assessment (LCA).

by Prof. Dr. Fabio Rubens Soares

Abstract

While Brazilian municipal solid waste (MSW) is most often collected and disposed of at "controlled” dumps and landfills, a large amount of refuse still ends up at irregular dumping sites. Unfortunately, there are few cases where waste is processed in a manner that provides additional benefits to local communities, for example, recovering energy from waste. The most common form of energy recovery practiced worldwide is converting it to electricity. In order to meet current energy needs and reduce fossil fuel emissions, this approach is a crucial component of any regional energy strategy and therefore should be considered wherever applicable. The present study quantified the feasibility of implementing alternative and complementary technologies for treatment and final disposal of the MSW of São Paulo to generate electricity with consideration of potential environmental impacts using life cycle assessment (LCA). The technologies considered were (i) disposal at landfill with biogas recovery, (ii) mechanical biological treatment and (iii) incineration. The program SimaPro 7.3.3 was used to analyse the life cycle impact (LCI) and life cycle impact assessment (LCIA).

The scope of the study, including the border and the detailing, was defined based on the technological treatment and disposal routes for MSW.. Results showed that, among the alternatives considered in this study, the electricity generated from the combined processes of a mechanical biological treatment system and incineration is the most attractive option in terms of minimizing the environmental impacts. Electricity generation from incineration process proved to be attractive not only in terms of environmental impacts, but also in terms of energy efficiency, yielding more energy than simply collecting biogas from landfill. Results were classified in terms of potential long-term impacts, i.e., considering the potential environmental impacts over a period of 100 years. When considering long-term impacts, the greatest areas of concern were regarding carcinogenic substances, non-carcinogenic substances, ecotoxicity, and eutrophication.

As a general conclusion, this study identifies current options and opportunities for Brazil, for the implementation of projects related to energy convertion from MSW, with a focus on the incineration process, with the caveat that there are still socio-political-economic barriers to the latter process, despite its environmental benefits and energy efficiency.

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published: , 2|2024
Keywords: Energy Recovery, Brasil

Dr Fabio Rubens Soares
Enviroservices / Universidade de São Paulo