RESUMO
Municipal solid waste (MSW) management in dense urban areas is a challenge for municipalities, especially in developing countries, which commonly have deficient waste management. For example, the metropolitan region of Goiás State, Brazil, has 19 municipalities that dispose of about 72.5% of total MSW in unlicensed MSW final disposal facilities. Therefore, this study analysed the investment and operating costs, and revenues of a municipal solid waste management facility, projected for 20 years, shared among these 19 municipalities. The economic viability analysis, has shown that, regardless of the management facility type, MSW collection and transport are the most expensive cost components, accounting for about 60% of MSW management operating costs. For an Internal Rate of Return of 0%, anaerobic digestion is 11% more expensive (in total) than using community composting. For 2040 (last year), the monthly MSW management tariffs will vary between 3.5 and 10.8 R$·inhabitant-1·month-1, depending on the municipality. So, as the unit price of biowaste treatments lowers with waste quantities, for the municipalities with large biowaste quantities, anaerobic digestion becomes recommended for its economic attractiveness. This study can serve as a model for other municipalities in Brazil and elsewhere, helping public decision makers to establish a strategy for MSW management.
Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Brasil , Cidades , Resíduos SólidosRESUMO
Municipal solid waste (MSW) management is a pressing concern for Goiás State, Brazil. Of the state's 246 municipalities, only 16 send their waste to licensed landfills. This means that 93% of the cities in Goiás dispose of their MSW inappropriately, in dumps or unlicensed landfills. This practice poses a danger to both the environment and to public health. On this basis, the goal of this study was to survey potential landfill sites in Goiás. A geographic information system tool was used to first identify Goiás landfills and dumps and then examine them, to check whether they are located in legally restricted areas. This tool cross-references morphology, land use and occupancy, conservation of the environment, public health and population projections for 2040. It then outputs restriction-free areas that are suitable for landfill construction. The results indicate that, by 2040, Goiás will have 59,500â¯km2 available for landfills, i.e., 17% of the state's total area. Conversely, 60% of the state's geographical area will be off limits for landfill construction. The most urgent need is in the Goiânia Metropolitan area, which will be producing about 40%, of 6,850â¯tâ day-1, of the MSW generated in the state by 2040. This metropolitan area will have the smallest restriction-free area for landfill construction (832â¯km2). A total of 235 MSW final disposal facilities were identified in Goiás: 15 licensed landfills, 23 unlicensed landfills and 197 dumps. Of these, 15 are in permitted areas, 38 are in areas subject to approval and 182 are in restricted areas. These numbers highlight the need for Goiás municipalities to terminate and/or readjust landfills and unlicensed dumps and to set up new MSW management facilities that conform to the legal and environmental requirements and the expected population growth.