Potential of plug flow digesters for biogas production in the Sri Lankan domestic context

Biogas production through anaerobic digestion is widely used to convert domestic and industrial waste into energy. In order to successfully adapt this technology for Sri Lankan domestic usage, it is necessary to identify the necessary operating conditions for optimum biogas generation. This study focused on analysing the effect of co-digestion ratios and organic loading rates on processing local domestic waste. Experiments were conducted on a laboratory scale plug flow anaerobic digester setup. The best methane yield was obtained with a co-digestion ratio of garden to kitchen waste of 70:30, at an Organic Loading Rate of 3.1 kgVS/day/m³. The energy potential of the generated biogas was evaluated in comparison to the average demand of households in the country, to establish the viability of biogas substitute to conventional energy sources. Future work is needed to validate the experimental results through mathematical modelling.