Enhancement of biogas production from rice husk using mechanical pretreatment (grinding) in Liquid Anaerobic Digestion (L-AD)

Biogas technology is an alternative solution to the energy crisis issue in Indonesia. This study focuses on determining the optimum value of grind size variations in biogas production using the Liquid Anaerobic Digestion (L-AD) from rice husk waste. It is consists of the preparation stage, total solids calculation, the operation phase, and results analysis. The rice husk is collected from Rowosari village, and it has been pre-treated by 6% NaOH of chemical pre-treatment. The physical treatment uses numerous grind sizes, including un-grinded rice husk as control, and the 10 mesh, 18 mesh, 35 mesh, 60 mesh of rice husk as an observed variable. All variables are duplicate into 12 reactors, and the biogas production is observed by collecting gas volume in each reactor for 60 days. The calculated biogas is expressed by ml/grTS. The result shows that the grind size of 10 mesh, 18 mesh, 35 mesh, and 60 mesh rice husk produces a total biogas rate of 54.95, 44.86, 58.13, and 72.14 ml/grTS respectively. The rice husk control produces 9.67 ml/gr TS as the lowest rate of biogas production compared to the others, while the 60 mesh rice husk becomes the highest biogas production rate.