TY - JOUR
T1 - Temperature-phased anaerobic co-digestion of food waste and paper waste with and without recirculation
T2 - Biogas production and microbial structure
AU - Li, Lu
AU - Kong, Zhe
AU - Qin, Yu
AU - Wu, Jing
AU - Zhu, Aijun
AU - Xiao, Benyi
AU - Ni, Jialing
AU - Kubota, Kengo
AU - Li, Yu You
N1 - Funding Information:
This work was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number JP 18J11397 (the first author) and Number JP 17J02720 (the second author).
Publisher Copyright:
© 2020
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Two temperature-phased anaerobic digestion (TPAD) systems (55 °C in the first reactor and 35 °C in the second reactor) with and without recirculation were operated in parallel for the co-digestion of food waste and paper waste. A long-term experiment was carried out for these two systems with the paper waste ratios elevated from 0 to 50%. The removal efficiencies of COD, TS, VS, carbohydrate and protein in the recirculated TPAD system were higher than those of the non-recirculated system. The successful acclimation of thermophilic cellulose-degrading bacteria in the first reactor (RT1), partly due to recirculation, ensured the effective degradation of cellulose when the paper waste ratio was higher than 40%, resulting in the production of large amounts of hydrogen in reactor RT1. In the absence of recirculation, the main substance produced in the first reactor of the non-recirculated system (T1) was lactic acid. This gradually led to over-acidification and a low degradation efficiency and no methane or hydrogen was produced in T1. Recirculation helped to establish a stable bacterial community capable of producing bio-hydrogen in reactor RT1. The relatively low pH of 5.5 in the RT1 inhibited the activity of hydrogenotrophic archaea without consuming hydrogen, facilitating high hydrogen production levels.
AB - Two temperature-phased anaerobic digestion (TPAD) systems (55 °C in the first reactor and 35 °C in the second reactor) with and without recirculation were operated in parallel for the co-digestion of food waste and paper waste. A long-term experiment was carried out for these two systems with the paper waste ratios elevated from 0 to 50%. The removal efficiencies of COD, TS, VS, carbohydrate and protein in the recirculated TPAD system were higher than those of the non-recirculated system. The successful acclimation of thermophilic cellulose-degrading bacteria in the first reactor (RT1), partly due to recirculation, ensured the effective degradation of cellulose when the paper waste ratio was higher than 40%, resulting in the production of large amounts of hydrogen in reactor RT1. In the absence of recirculation, the main substance produced in the first reactor of the non-recirculated system (T1) was lactic acid. This gradually led to over-acidification and a low degradation efficiency and no methane or hydrogen was produced in T1. Recirculation helped to establish a stable bacterial community capable of producing bio-hydrogen in reactor RT1. The relatively low pH of 5.5 in the RT1 inhibited the activity of hydrogenotrophic archaea without consuming hydrogen, facilitating high hydrogen production levels.
KW - Anaerobic co-digestion
KW - Biogas
KW - Microbial structure
KW - Paper waste
KW - Recirculation
KW - Temperature-phased
UR - http://www.scopus.com/inward/record.url?scp=85082557411&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85082557411&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.138168
DO - 10.1016/j.scitotenv.2020.138168
M3 - Article
C2 - 32247142
AN - SCOPUS:85082557411
VL - 724
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
M1 - 138168
ER -