THE INFLUENCE OF INOCULUM TYPE ON MONO DIGESTION PERFORMANCE OF PAPER WASTE

ABSTRACT This research focused on the influence of inoculum type on biogas yield of paper waste using cow dung and rumen fluid as inoculums. Using 100 mL serum bottles as bioreactors, the experiment tested different proportions of substrate and inoculums (rumen fluid or cow dung) over a retention time of 30 days, and biogas production was measured using downward displacement method. From the results, rumen fluid inoculum achieved a slightly higher maximum daily biogas yield compared to cow dung; however, the difference was not significant (p>0.050). The highest cumulative biogas yield was observed in rumen contents reactor (894 mL gVS-) and was two times higher than the yield in cow dung reactor (444 mL gVS-') while the control had the lowest cumulative biogas yield of (159 mL gVS-'). The microbial load and population associated with the substrate and inoculums revealed higher bacterial concentration in cow dung and rumen fluid compared to paper waste. The microbial groups isolated and identified from substrate and inoculums were; Bacillus sp., Pseudomonas sp., Staphylococcus aureus, Escherichia coli, Enterobacter spp., Clostridium spp., Klebsiella pneumonia, Vibrio parahaemolyticus, Salmonella sp., Shigella sp., Proteus sp. and Serratia marcescens. Mono-digestion of paper waste with rumen fluid inoculum resulted in a significantly (p < 0.05) higher biogas yield compared to cow dung inoculum. Mono digestion of paper waste with rumen fluid can be a viable option for managing these waste stream. Additionally, using appropriate inoculum (rumen fluid) biogas production can be enhanced during anaerobic digestion of paper waste.