Anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) is a promising strategy for sustainable waste management and renewable energy generation in small municipalities. This study evaluated the biochemical methane potential (BMP) and biogas yield of OFMSW from five municipalities in southern Brazil sharing a regional landfill. Composite samples were analyzed for total solids, volatile solids, and soluble chemical oxygen demand (sCOD), and elemental composition including trace metals. BMP tests were conducted under mesophilic conditions (39 degrees C) using a substrate-to-inoculum ratio <= 0.5 (VS basis) following VDI 4630 guidelines. Under mesophilic conditions, biogas yields ranged from 519 to 733 m & sup3; t-1 VS, and methane yields from 296 to 445 m & sup3; t-1 VS, with sCOD correlating with energy potential. Elemental analysis revealed that molybdenum presence coincided with higher methane yields, while elevated iron and tungsten concentrations were observed in lower-performing samples. Heavy metal concentrations (Pb, Cd, Cr, Hg and As) exceeded regulatory limits for agricultural digestate application. Estimated regional biogas production reached 2,212 m & sup3; day-1, supporting decentralized anaerobic digestion systems in rural contexts. These findings demonstrate the technical feasibility of biogas recovery from OFMSW and provide data to inform localized waste-to-energy initiatives.
The growing demand for cleaner and more efficient internal combustion engines has increased interest in dual-fuel strategies using renewable fuels such as biogas. This study applies multi-response optimisation to a simulated biogas/diesel RCCI engine using the Taguchi Design of Experiments (DoE) method, considering variations in engine load and biogas energy substitution ratio (ESR). Taguchi analysis identified optimal operating points with fewer experiments, while linear regression provided predictive models for key performance and emission parameters. Analysis of Variance (ANOVA) assessed statistical significance and quantified the relative contribution of each factor. All analyses were conducted using Minitab 22 statistical software. Results showed that higher engine loads with moderate biogas ESR minimised combustion variability, improved brake thermal efficiency, and lowered HC emissions, while NO formation followed expected thermal trends. This integrated approach demonstrates the feasibility of achieving a balanced trade-off between efficiency and emissions in simulated biogas-diesel RCCI operation.
