Biogas Production from Palm Oil Mill Effluent Co-Digested with Selected Animal Wastes in a Batch System Bioreactor

This study evaluated biogas production from palm oil mill effluent (POME) co-digested with pig dung (PD), cow dung (CD) and poultry manure (PM). Ten liter (10L) capacity batch bioreactors were used, and operated at ambient temperature (28OC-36OC) and pH range of 6.5-8.5 for 45days. The bioreactors were charged with different ratios (3L/520g, 3L/600g and 3L/680g) of POME/PD, POME/CD, POME/PM while POME alone was the control. Proximate composition of the substrates was estimated, and the methane content of the produced biogas determined by using Gas Chromatography. Microbial analysis was done by standard methods. The result indicated the presence of Escherichia coli, Staphylococcus, Pseudomonas, and Bacillus among others. The cumulative biogas production observed in bioreactor charged with POME/PD 520g, POME/PD 600g, POME/ PD 680g; POME/CD 520g, POME/CD 600g, POME/CD 680g; POME/PM 520g, POME/PM 600g and POME/PM 680g were (6.529dm3), (6.171dm3), (9.306dm3); (8.035dm3), (10.344dm3), (7.570dm3); (4.601dm3), (6.462dm3), (7.995dm3) respectively and POME control (4.635 dm3). The result showed that POME/CD3L: 600g exhibited the highest performance in biogas production (10.344dm3), and the highest percentage methane content (77.89%). Analysis of variance (ANOVA) indicated that biogas yield in POME/CD 600g was significant different (P = 0.05) from every other treatment. These results show that biogas and its methane content production can be enhanced efficiently through co-digestion process.