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Updated: Jul 4, 2026

Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Influence of inoculum-to-substrate ratio on process stability and microbial community structure in anaerobic
Roshita Sharma1, Vanshikha Gupta1, Vijai Pal1
1Bioprocess Technology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, 474002, India.
Abstract:
Anaerobic digestion is a pivotal technology for modern sanitation. This study investigates the impact of inoculum-substrate ratio (ISR) on anaerobic digestion of human faecal matter (HFM). To determine the anaerobic digestion efficiency of HFM, the experiments were conducted using an automatic biomethane potential test system with ISRs ranging from 0.33 to 3. Higher ISRs (1, 2, and 3) resulted in improved volatile solids reduction, increased hydrolysis rates, and higher cumulative methane production compared to lower ISRs. Kinetic modelling revealed that an ISR of 3 exhibited the highest hydrolysis rate constant and shortest lag phase. Analysis of volatile fatty acids showed that higher ISRs mitigated acid accumulation and maintained pH stability. Microbial community analysis demonstrated shifts in bacterial and archaeal populations across different ISRs, with higher ratios fostering greater diversity and abundance of hydrolytic and methanogenic microorganisms. The findings offer essential insights for enhancing the anaerobic digestion of HFM, promoting sustainable waste management and renewable energy production.
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