Prompt Description

The sustainable management of organic waste remains a significant global challenge, with vegetable waste (VW) and livestock-derived materials being major contributors to environmental degradation and energy resource depletion. This study optimized the effect of temperature on biogas production, methane content, and volatile fatty acid (VFA) concentration during the co-digestion of VW and cattle rumen content (CRC) under mesophilic (35-48 °C) and thermophilic (50-60 °C) conditions. Batch digesters with a 5 L capacity were operated with substrate mixtures (VW:CRC) at an organic loading rate (OLR) of 2-4 kg VS/m³/day, maintaining a 40-day retention time and a pH range of 6.8-7.2. The results indicated that the highest biogas yield was 0.62 L/g VS, with a methane content of 62%, achieved at 42 °C with a 70:30 VW:CRC ratio. This represents a 38% and 18% improvement compared to VW mono-digestion and thermophilic operation, respectively. Temperature optimization reduced the lag phase by 50% and increased the reduction of volatile solids (VS).