Effect of Biochar Addition on Biogas Production Using Konjac Waste through Mesophilic Two-Phase Anaerobic Digestion

This study aimed to investigate the influence of biochar supplementation in the mesophilic two-phase anaerobic digestion process for konjac waste.

Reactors with a working volume of 60 mL were utilised to incubate cultures containing biochar. In the first phase, the cultures were maintained at 32 °C and a pH of 5 to facilitate the production of hydrogen. In the second phase, the cultures were adjusted to 37 °C and a pH of 7 to promote methane production. The concentration of konjac flour waste varied between 0 and 500 g/L, while the ratio of biochar addition ranged from 0 to 25 g/L. Biogas production was measured daily using the volume displacement method, and the pH of the cultures was monitored both before and after the experiment.

The findings show that using biochar has a beneficial effect on biogas production from konjac flour waste. During the initial phase of the experiment, incorporating biochar with a concentration of 15 g/L led to substantial improvements, elevating the maximum H₂ production rates by 9.6%. Furthermore, the addition of biochar led to an 84% increase in H₂ yield during the initial phase. Similarly, in the second phase, introducing biochar with a concentration of 15 g/L resulted in a 22.2% increase in the maximum CH₄ production rates and a 2.5 times increase in CH₄ yield.

Overall, this work confirms the beneficial effects of biochar on the H₂ and CH₄ production from konjac flour waste using the mesophilic two-phase anaerobic digestion method for sustainable energy.