The Influence of Microbial Consortium and C/N Ratio to Biogas Production from Rice Husk Waste by Using Solid State Anaerobic Digestion (SS-AD)

Rice husk is one of agricultural waste which have a potential to be processed into biogas. The aim of this research was to study the effect of enzymatic pretreatment and C/N ratio to biogas production from rice husk by solid state anaerobic digestion (SS-AD). This research were operated in batch system and at room temperature. TS was set 21 %. Enzymatic pretreatment was conducted using lignase enzyme. C/N ratio was varied from 35, 40, 45, and 50. The variation of C/N ratio is made by adding technical urea to the substrate. Biogas formed was measured by using water displacement method every two days. The result showed that enzymatic pretreatment could increase biogas production varied from 30 to 55 %. The highest biogas production was obtained at C/N ratio 35. Specific biogas production on C/N ratio of 35, 40, 45, and 50 were 11.6, 10.2, 9.8 and 9.4 ml/grTS, respectively. SS-AD has volumetric loading of biogas production higher than generally in liquid anaerobic digestion (L-AD). Combined with our previous research with variations of C/N ratio 20, 25, 30, and 35, we obtained an optimum C/N ratio at 35.