Comparison of the environmental impact of incineration and landfilling in São Paulo City as determined by LCA

Abstract

Life cycle assessment was employed to compare the environmental impact of incineration and the landfilling of municipal solid waste in São Paulo City, Brazil. Incineration with energy recovery and landfilling treatment systems were assessed in five different scenarios. Three incineration scenarios with different ash treatment systems were evaluated: incineration with ash disposal, with ash melting, and with an ash reuse system (brick production). Two landfilling scenarios were evaluated, namely, with and without energy recovery. Energy consumption, recovered resources, and emissions to the air and water were quantified and analyzed in terms of their impact potentials. Global warming, acidification, and nutrient enrichment were assessed as environmental impact categories. Electricity generation in these waste treatment systems did not result in a significant reduction in overall environmental impact, because Brazilian electricity is mainly hydro-based. Incineration with ash disposal to a landfill site resulted in the lowest impact values for all impact categories assessed in this study. Among the incineration scenarios, the reuse of ash for brick production resulted in a higher environmental impact due to an increase in energy consumption. Landfilling had a higher environmental impact than incineration. Landfilling with energy recovery had a slightly lower environmental impact than the landfilling without energy recovery. Finally, it was demonstrated that significant reductions in environmental impact could be obtained through a change in the solid waste management of São Paulo City.