Enhancing biogas production through optimized organic loading rate and temperature in anaerobic digestion of municipal solid waste: A study from Aleppo

Background: Aleppo produces large amounts of municipal solid waste, making environmentally safe disposal essential. Dry anaerobic digestion is a promising method for treating the organic fraction of municipal solid waste (OFMSW) while generating renewable energy. Key parameters such as pH, hydraulic retention time (HRT), organic loading rate (OLR), and temperature strongly affect biogas yield. Methods: This study examined semi-continuous dry anaerobic digestion of OFMSW from Aleppo using two digesters operated at 35 °C and 45 °C. The substrate contained 25.03% total solids (TS) and 23.32% volatile solids (VS). The digesters were run for 70 days with OLRs of 4.66, 6.99, and 9.33 kg VS/m³.day. Results: The best performance was observed at 45 °C and an OLR of 6.99 kg VS/m³·day, producing 0.431 m³/kg VS of biogas with a VS removal efficiency of 76.34%. Compared to 35 °C, digestion at 45 °C increased VS removal efficiency and biogas yield by 14.34% and 19.25%, respectively. However, raising OLR to 9.33 kg VS/m³·day reduced both efficiency and productivity at both temperatures. Conclusion: Higher temperatures enhanced both VS removal and biogas production, but excessive OLR negatively impacted performance. The study identifies 45 °C and 6.99 kg VS/m³·day as optimal conditions, providing guidance for improving OFMSW treatment and maximizing energy recovery. These results highlight the potential of dry anaerobic digestion as a sustainable solution for managing organic waste in Aleppo and similar contexts.