Methane from Human Excreta: Comparative Assessment of Batch and Continuous Biomethanation Process

Abstract

Treatment of human excreta (HE) is necessary before its discharge into natural water body. Untreated discharge may cause several ill effects for environment and human health. Anaerobic digestion of human excreta can unravel this problem along with production of biogas. Anaerobic digestion process may be either batch type or continuous type. In present study, human excreta were degraded anaerobically by both the means in the laboratory scale 5L capacity glass digesters. The comparative assessment between batch digestion and continuous digestion was carried out. The digesters were fed with human excreta at 6% Total Solids and operated at ambient temperature of 20-37°C for 99 days. The results show that average biogas production in batch feeding process is 322.78 mLday-1 whereas in continues digestion it is 382 mLday-1. Total biogas production during 99 days in batch digestion and continue digestion is 31955.1 mL and 37833.9 mL respectively. Average methane content in biogas produced in continuous and batch digestion was 68.0% and 67.4% respectively. Results conclude that human excreta can be successfully digested anaerobically to produce biogas with good methane content either by batch or continuous digestion process.

Keywords

• methane
• human excreta
• biogas
• renewable energy