Micro-scale anaerobic digestion of point source components of organic fraction

4. Conclusion

Six hitherto untried OFMSW feedstocks were subject to a fermentation simulating anaerobic digestion in the inlet of the pre-treatment zone of a plug-flow biogas reactor for biomass. The feedstocks used were those that form potential point source feedstocks in Bangalore and the IISc campus. As expected, all of the feedstocks underwent a significant level of degradation. Banana peels, cabbage leaves, and citrus peels underwent rapid decomposition, losing over 80% of their mass in 4 d with a concomitant potential to generate a large VFA flux. This study confirms the potential for such an occurrence. PFBRs fed predominantly with such feedstocks will tend to have a low pH zone in the inlet, and operation techniques need to be developed to overcome this for a stable and trouble- free biomethanation process, especially when small and simple decentralized biogas plants are planned for OFMSW rich in these feedstocks. Feedstocks such as leaf litter (more specifically, bamboo leaves and teak leaves) and soiled newsprint also have a moderate potential to decompose between 30% and 45% of TS, and consequently, a significant amount of the feed will be expected to come out of the digester as digested compost. There was no rapid decomposition phase observed for these feedstocks, and biogas production did not seem to be inhibited by operating conditions.

Micro-scale anaerobic digestion of point source components of organic fraction of municipal solid waste
H.N. Chanakya ^{a ,*}, Isha Sharma ^a, T.V. Ramachandra ^{a , b} ^a Centre for Sustainable Technologies, (formerly ASTRA), Indian Institute of Science, Bangalore 560 012, India ^b Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012, India