RESUMEN
The anaerobic treatment of raw vinasse in a combined system consisting in two methanogenic reactors, up-flow anaerobic sludge blanket (UASB) + anaerobic packed bed reactors (APBR), was evaluated. The organic loading rate (OLR) was varied, and the best condition for the combined system was 12.5 kg COD m-3day-1 with averages of 0.289 m3 CH4 kg COD r-1for the UASB reactor and 4.4 kg COD m-3day-1 with 0.207 m3 CH4 kg COD r-1 for APBR. The OLR played a major role in the emission of H2S conducting to relatively stable quality of biogas emitted from the APBR, with H2S concentrations <10 mg L-1. The importance of the sulphate to COD ratio was demonstrated as a result of the low biogas quality recorded at the lowest ratio. It was possible to develop a proper anaerobic digestion of raw vinasse through the combined system with COD removal efficiency of 86.7% and higher CH4 and a lower H2S content in biogas.
Asunto(s)
Biocombustibles , Reactores Biológicos , Sulfuro de Hidrógeno/metabolismo , Metano/metabolismo , Aguas del Alcantarillado/microbiología , AnaerobiosisRESUMEN
The effect of natural mineral on the mono-digestion of maize straw was evaluated in continuously stirred tank reactors (CSTRs) at 38 °C. Different strategies of mineral addition were studied. The organic loading rate (OLR) was varied from 0.5 to 2.5 g volatile solid (VS) L(-1) d(-1). A daily addition of 1 g mineral L(-1) in reactor 2 (R2) diminished the methane production by about 11 % with respect to the initial phase. However, after a gradual addition of mineral, an average methane yield of 257 NmL CH4 g VS(-1) was reached and the methane production was enhanced by 30 % with regard to R1. An increase in the frequency of mineral addition did not enhance the methane production. The archaeal community was more sensitive to the mineral than the bacterial population whose similarity stayed high between R1 and R2. Significant difference in methane yield was found for both reactors throughout the operation.