Influence of Inoculum Content on Performance of Anaerobic Reactors for Treating Cattle Manure using Rumen Fluid Inoculum

Biogas productions of cattle manure using rumen fluid inoculums were determined using batch anaerobic digesters at mesophilic temperatures (room and 38.5 C). The aim of this paper was to analyze the influence of rumen fluid contents on biogas yield from cattle manure using fluid rumen inoculums. A series of laboratory experiments using 400 ml biodigester were performed in batch operation mode. Given 100 grams of fresh cattle manure (M) was fed to each biodigester and mixed with rumen fluid (R) and tap water (W) in several ratio resulting six different M:W:R ratio contents i.e. 1:1:0; 1:0.75:0.25; 1:0.5:0.5; 1:0.25:0.75; and 1:0:1 (correspond to 0; 12.5; 25, 37.5; 50, and 100 % rumen, respectively). The research showed that, either in room temperature as well as in 38.5 C, the best performance of biogas production was obtained with rumen fluid in the range of 25-50 %. Increasing rumen content will also increase biogas production. This is suggest that, due to the optimum total solid (TS) content for biogas production between 7-9 % (or correspond to more and less manure and total liquid 1:1), the rumen fluid content of 50 % will give the best performance for biogas production. However, intensively research need to be carried in further research to study interaction effect of TS and rumen content to biogas production.