POTENCIAL DE GERAÇÃO DE BIOGÁS A PARTIR DA FRAÇÃO ORGÂNICA DE RESÍDUOS SÓLIDOS URBANOS

Abstract

The present study aimed to evaluate the potential of biogas generation from the organic fraction of fresh municipal solid waste, collected at the Guarapuava municipal landfill, using BMP (Biochemical Methane Potential) assays. For this proposal, the biogas production was evaluated during 91 days, in bench scale anaerobic biodigesters, consisting of 250 mL borosilicate flasks, sealed with lids made of nylon and registers with manometer and valves (for the discharge and biogas monitoring) and loaded as two treatments: substrate (2 g of fresh waste inoculated with 100 mL of anaerobic sludge) and inoculum (100 mL of anaerobic sludge – blank assays). The internal pressure of the flasks was daily monitored and converted in terms of daily and cumulative biogas generation at Standard Temperature and Pressure. The average biogas generation, assigned to the waste, was 193.27 mL or 96.64 mL.gdried waste -1; in terms of volatile solids (VS), the biogas generation by the waste was equal to 122.66 mL.gVS added -1 and 235.90 mL.gVS degraded -1. The biogas produced by substrate showed an average H2S concentration in the range of 39-460 ppm and a CH4 concentration in the range of 71-89% on average. The principal components analysis has indicated the variables that were related more to biogas production were the pH and volatile solids. The application of the model LandGEM using different approaches (practical, with experimentally calculated variables, and theoretical, with default values) showed that theoretically the biogas production can be three times higher than the practical results and the actual distribution period of the highest generation rates can be much shorter than expected when default values are used. This indicates that the international database may not be adequate to the reality of landfills in Brazil.