Anaerobic Biogas Production Using Microalgae Chlorella sp. as Biomass Co-digested by Cow Manure and Cow Rumen Fluid as Inoculum.

Abstract

World’s demand for energy is steadily increasing following population increase, on the other hand reserves for fossil and coal energy are limited. Therefore research for renewable sources of energy is important. Biogas produced from renewable source could be one of the answer for future energy production. Researches regarding biogas production utilizing microalgae biomass such as Chlorella sp. have received much attention. In this study, co-digestion of Chlorella sp. “CD01” isolated from Cideng/Krukut River using cow rumen fluid and cow manure as inoculum were used to enhance biogas production. Our experiment used a simple non-stirred batch anaerobic bioreactor that was carried out for 29 days. Biogas volume, COD value, and microorganism were the parameters in this study. Our result showed that Chlorella sp. “CD01” and rumen fluid alone could not produce biogas. Co-digestion of Chlorella sp. “CD01” substrate and rumen fluid inoculum produced 314.5 mL biogas with yield of 43.23 mL/gTS. Co-digestion of Chlorella sp. “CD01” substrate and manure inoculum produced 1758 mL biogas with yield of 98.96 mL/gTS. The best substrate inoculum ratio (S/X) in this study was 0.33 based on cumulative biogas production. Attempts for isolating anaerobic culture from each reactor had been done using methanogenic selective media. Two methanogens isolates were morphologically characterized.