Avaliação do ciclo de vida e apoio à decisão em gerenciamento integrado e sustentável de resíduos sólidos urbanos

Abstract

The study of the participation of different stakeholders through structured techniques to support decision making in building future alternatives or scenarios for the collection and treatment of municipal solid waste was applied to the city of Porto Alegre, Rio Grande do Sul, Brazil. Using the life cycle assessment tool, eight different scenarios, constructed with the participation of social stakeholders and municipal technicians, were evaluated. Different collection alternatives (selective and containerized) and treatment (recycling, composting, anaerobic digestion, thermal processes and landfill disposal) were considered.We conclude that the application of the life cycle assessment tool facilitates decision-making support systems in municipal solid waste management. In our case study, the most sustainable scenario was built by municipal waste management stakeholders.Keywords: sustainability; management; solid waste; stakeholders; Porto Alegre; IWM-2; life cycle assessment (LCA). INTRODUÇÃOO correto gerenciamento dos resíduos sólidos é um dos principais desafios dos grandes centros urbanos no início deste novo milênio. Até bem pouco tempo atrás, no Brasil e na América Latina, as ações no campo dos resíduos sólidos se restringiam à limpeza urbana, ficando o tratamento e a disposição final dos resíduos completamente relegados. Ao longo das últimas duas décadas, várias ações e projetos têm sido propostos para a melhoria da disposição final e o tratamento dos resíduos sólidos urbanos (RSU). Dados da Pesquisa Nacional Saneamento Básico (PNSB) apontam uma evolução de 1,1%, em 1989, para 27,7% dos municípios do Brasil, em 2008, que dispõem seus resíduos de forma correta em aterros sanitários (IBGE, 2010). O problema da disposição inadequada ainda permanece, principalmente nos pequenos municípios. Ainda, segundo a mesma pesquisa, somente 18% dos municípios têm algum programa de coleta seletiva, e o índice de compostagem é da ordem de, apenas, 1%.Muitas das soluções que têm sido propostas trazem em si o equívoco da autossuficiência. São soluções isoladas e estanques, que não contemplam a questão dos resíduos do momento de sua geração até a disposição final, passando pelo seu tratamento. Estas "soluções", mesmo sendo boas em princípio, não conseguem resolver o problema como um todo.

Life Cycle Assessment of current and prospective waste management systems in Brazil

“…Nevertheless, energy recovery and substitution of marginal electricity scenario 1.e contributed significant savings in GWP, ODP, HT (CE), PT, EPF, ECF and DAMR (due to steel recycling). The results of this scenario are similar to those of Reichert and Mendes (2014) Further on, the addition of wet stream treatment resulted in interesting observations. At first glance results suggested system 2.c(e), which is based on wet stream enclosed composting, as having the least impact in most categories.…”

“…or full management systems that compare largely theoretical system scenarios (GoulartCoelho and Lange, 2018;Mersoni and Reichert, 2017;Reichert and Mendes, 2014) to the current management in different municipalities. Many of these case studies refer geographically to the populous southeast Brazil (e.g.…”

Life Cycle Inventory and assessment of the municipal solid waste management system: a case study in a municipality in southern Brazil

“…According Tarantini et al (2009), the potential impact for eutrophication is mainly due to high concentrations of nitrates and ammonia present in the landfill slurry, even if the waste is properly treated in the Treatment Plant. Reichert and Mendes (2014), states that eutrophication concerns the potential impacts related to the excessive concentration of nutrients, especially nitrogen and phosphorus. Figure 7 shows the impact of eutrophication contribution in the various stages of each of the scenarios.…”

“…Over the past two decades, various actions and designs have been proposed for improving the treatment and disposal of municipal solid waste (Reichert and Mendes, 2014). The approval of Law 12.305 (Brasil, 2010) has supported a comprehensive guideline to lead Brazil towards a more sustainable waste management system.…”

“…According to Turner et al (2015), this is because recycling materials into new (secondary) products can displace production of primary products that may require significant inputs of energy and raw materials. Reichert and Mendes (2014) states that the management of municipal solid waste, depending on the different alternatives and techniques used to handle, transport, process, treat and dispose of waste has the potential to generate environmental impacts resulting from gaseous emissions, liquid and final waste of the various stages of the management system. In order to provide this technical background, the Life Cycle Assessment Tool (LCA) is a concrete possibility.…”