Gerenciamento de resíduos sólidos urbanos de Feira de Santana-BA: demanda energética e pegada de carbono

Abstract

Municipal Solid Waste Management (MSWM) with disposal of material in landfills is a practice widely adopted in Brazil. The environmental performance quantification in MSWM supports the proposition of optimized practices. The Life Cycle Assessment (LCA) was applied in this study to evaluate the MSWM, having as functional unit 1 tonne of material managed in Feira de Santana, state of Bahia, Brazil. The system boundary of the MSWM in this study included the material managed in collection, transportation, treatment, disposal and leachate handling stages. The base scenario (C1) considered the disposal of material in a landfill, with flare methane burning. Scenario 2 (C2) adopted an evolution from C1, in which biogas started to be used to generate electricity. Scenario 3 (C3) considered the recovery of resources by recycling the total fraction of dry material such as: Paper, Plastic, Metal and Glass (41 % of the total mass of MSW) and the composting of the wet organic fraction (49 % of the mass total MSW). In Scenario 4 (C4), recycling identical to C3 was adopted and anaerobic digestion of the organic fraction with biogas collection (49 % of the total MSW mass) followed by composting of the digested material. The foreground inventory used representative data for the evaluated scenarios, while the background inventory used the ecoinvent ™ database in the Simapro® software with the Cumulative Energy Demand (CED) and 100 year IPCC-2013 methods. C1 presented the highest values of the evaluated categories, both for CED (215 MJ ∙ t − 1) and for Greenhouse Gas (GHG) emissions (449 kg CO2 eq ∙ t − 1). The C1 presented the greatest contribution of the DEA in the collection and transport, and of GHG at the sanitary landfill. C3 and C4 showed better performances of both CED (–22 550 e – 22 578) MJ ∙ t − 1 and GHG (– 645 e – 622) kg CO2 eq ∙ t − 1 , respectively, due to avoided products mainly from recovered materials . Therefore, the scenarios proposed with the recovery of resources showed potential for reducing the CED and GHG emissions of the MSWM and support the transition to a circular economy.