Abstract

Anaerobic high-solid treatment (HST) for processing food waste and biogas production is a viable technology with considerable commercial potential. In this study, we examined and compared mesophilic and thermophilic industrial-scale plug-flow digesters. The HSTs demonstrated reasonable biogas yields from food waste (0.4-0.6 Nm(3)CH(4)/kg volatile solids). However, during operation at thermophilic conditions ammonia inhibition (similar to 2 g NH3-N/L) and acid accumulation (6-14 g/L) caused severe process disturbance. Microbial community structures diverged between the processes, with temperature appearing to be a strong driver. A unique feature of the thermophilic HSTs was high abundance of the uncultivated Clostridia group MBA03 and temperature fluctuations in one mesophilic HST were linked to drastically decreased abundance of methanogens and relative abundance of Cloacimonetes. The process data obtained in this study clearly demonstrate both potential and challenges in HST of food waste but also possibilities for management approaches to tackle process imbalance and restore process function.

Keywords

Anaerobic digestion organic fraction of municipal solid waste; Full-scale dry digestion; Plug-flow reactors; Temperature

Published in

Bioresource Technology
2020, volume: 304, article number: 122981
Publisher: ELSEVIER SCI LTD

Authors' information