Factors Affecting Anaerobic Biogas Digestion from Cassava Pulp and Wastewater

Abstract

This study aims to investigate the factors affecting biogas production from cassava pulp and wastewater. Experiments were conducted using five ratios of cassava pulp to wastewater: 1:1, 2:1, 3:1, 1:2, and 1:3. ANOVA analysis revealed that the ratios significantly influenced biogas production, with the 1:3 ratio yielding the highest gas output of 8.81 liters on day 13. In comparison, the 1:2 ratio produced 6.17 liters, while the other ratios (1:1, 2:1, and 3:1) resulted in significantly lower outputs. Further experiments using an 80-liter fermenter at the 1:3 ratio examined stirring speeds of 45 and 110 rpm. The results showed that 110 rpm improved microorganism and nutrient distribution in the fermenter, reducing the accumulation of inhibitory substances such as fatty acids. This led to biogas production starting on day 5 and increasing steadily to a maximum of 45.14 liters on day 13. In contrast, the 45 rpm stirring speed began biogas production on day 7, with a peak output of only 21.58 liters. These findings confirm that the 1:3 ratio and a stirring speed of 110 rpm are optimal for biogas production from cassava pulp and wastewater. This research can be applied to enhance biogas production efficiency in industrial settings.