Biogas opportunities in Curitiba : Analysis of business potential for biogas production from municipal solid waste

Abstract: The Brazilian city ofCuritiba produces 2 500 tons of MSW (municipal solid waste) per day that is landfilled.In an effort to find a more sustainable solution for waste management, the objective of this study was to investigate the potential for producing biogas from anaerobic digestion by analyzing the feasibility of small-scale decentralized biogas production as well as centralized production at commercialscale. A field study was carried out to map specific local circumstances and togather data by interviews and literature. Different methods of attaining the organic waste were reviewed and the options for biogas production were evaluated by comparing the highest investment cost admissible for a positive netpresent value of a prospective investment with estimations of investment costs from literature sources. Small-scale decentralized biogas production was found to be the most economically and socially viable option. For centralized production, the results were inconclusive but indicated the potential of profitable business cases. It is estimated that wet digestion in a floating-drum ortubular digester is most suitable for small scale applications while acontinuously dry digestion system is best suited for large scale biogasproduction in Curitiba. The sensitivity analysis showed that the amount oforganic waste available as well as the price of sold products had the biggest economic impact in the scenarios. It was found that any implementation of controlled anaerobic digestion would decrease the total global warming potential of the waste management system. It is recommended that the municipality proceed with and expand a pilot project at Mercado Regional, as well as exploring possibilities for more efficient waste collection, along with gathering more specific data on compositions and quantities for different waste flows. The study was carried out in the scope of a cooperation between KTH, the Swedish EnvironmentalProtection Agency, Municipality of Curitiba and local universities in Paraná,Brazil.