Impact of Co-digestion and Slurry concentration on biogas production from Kitchen wastes of Musa paradisiaca (Unripe plantain fruit peels) and Phaseolus vulgaris (Bean peels).

The efficient and useful conversion of kitchen waste into biogas will mitigate the health and environmental challenges caused by their indiscriminate disposal. This study compared the potential yields of biogas from plantain peels chaff (P) and bean peels chaff (B) when anaerobically digested in singles and when combined, and when digested in different slurry concentrations. Two combinations of the substrates were used; PB1 consisted of P and B combined in the ratio of 1:0.691 respectively, while PB2 had an equal ratio (1:1) of P and B. The substrates were digested anaerobically in three slurry concentrations representing substrate/water mixing ratios of 1:5 (S1), 1:10 (S2) and 1:15 (S3). The substrates were digested for thirty-seven days after augmentation with cow rumen liquor. Proximate analysis of the substrates was also done. Biogas was collected using the water displacement method. Results revealed that the total solids (%) of the substrates were 90.12 (P), 96.03 (B), 84.15 (PB1), and 84.94 (PB2). The carbon/nitrogen (C/N) ratios ranged from 9.04 to 15.3. PB1 yielded the highest mean volume of biogas per day (10.8 cm3/day) while P yielded the least (8.07 cm3/day). Results revealed that biogas yields increased as slurry concentration increased. The difference in yields with respect to co-digestion was not significant, whereas the difference with respect to slurry concentration was highly significant. We conclude that the peels of Musa paradisiaca and Phaseolus vulgaris could be converted into biogas whether digested individually or combined, and that higher slurry concentrations are recommended for a higher production of biogas.