TY - JOUR
T1 - Food waste and sewage sludge co-digestion amended with different biochars
T2 - VFA kinetics, methane yield and digestate quality assessment
AU - Johnravindar, Davidraj
AU - Wong, Jonathan W.C.
AU - Chakraborty, Debkumar
AU - Bodedla, Govardhan
AU - Kaur, Guneet
N1 - Funding Information:
This work was supported by Environment and Conservation Fund, Hong Kong Administrative region (Grant No. ECF Project 108/2018 ). The support from United Kingdom Biochar Research Centre for biochar samples is appreciated.
Funding Information:
This work was supported by Environment and Conservation Fund, Hong Kong Administrative region (Grant No. ECF Project 108/2018). The support from United Kingdom Biochar Research Centre for biochar samples is appreciated.
Publisher Copyright:
© 2021
PY - 2021/7/15
Y1 - 2021/7/15
N2 - This work investigated the impact of the addition of different biochar types on mitigation of volatile fatty acid (VFA) accumulation, methane recovery and digestate quality in mesophilic food waste-sludge co-digestion. Four biochars derived from agricultural and sludge residues under different pyrolysis temperatures were compared. Specific biochar properties such as pH, surface area, chemical properties and presence of surface functional groups likely influenced biochar reactions during digestion, thereby resulting in a varying performance of different biochars. Miscanthus straw biochar addition led to the highest specific methane yield of 307 ± 0.3 mL CH4/g VSadded versus 241.87 ± 5.9 mL CH4/g VSadded from control with no biochar addition over 30 days of the co-digestion period. Biochar supplementation led to enhanced process stability which likely resulted from improved syntrophic VFA oxidation facilitated by specific biochar properties. Overall, a 21.4% increase in the overall methane production was obtained with biochar addition as compared to control. The resulting digestate quality was also investigated. Biochar-amended digester generated a digestate rich in macro- and micro-nutrients including K, Mg, Ca, Fe making biochar-amended digestate a potential replacement of agricultural lime fertilizer. This work demonstrated that the addition of specific biochars with desirable properties alleviated VFA accumulation and facilitated enhanced methane recovery, thereby providing a means to achieve process stability even under high organic loading conditions in co-digestions. Moreover, the availability of biochar-enriched digestate with superior characteristics than biochar-free digestate adds further merit to this process.
AB - This work investigated the impact of the addition of different biochar types on mitigation of volatile fatty acid (VFA) accumulation, methane recovery and digestate quality in mesophilic food waste-sludge co-digestion. Four biochars derived from agricultural and sludge residues under different pyrolysis temperatures were compared. Specific biochar properties such as pH, surface area, chemical properties and presence of surface functional groups likely influenced biochar reactions during digestion, thereby resulting in a varying performance of different biochars. Miscanthus straw biochar addition led to the highest specific methane yield of 307 ± 0.3 mL CH4/g VSadded versus 241.87 ± 5.9 mL CH4/g VSadded from control with no biochar addition over 30 days of the co-digestion period. Biochar supplementation led to enhanced process stability which likely resulted from improved syntrophic VFA oxidation facilitated by specific biochar properties. Overall, a 21.4% increase in the overall methane production was obtained with biochar addition as compared to control. The resulting digestate quality was also investigated. Biochar-amended digester generated a digestate rich in macro- and micro-nutrients including K, Mg, Ca, Fe making biochar-amended digestate a potential replacement of agricultural lime fertilizer. This work demonstrated that the addition of specific biochars with desirable properties alleviated VFA accumulation and facilitated enhanced methane recovery, thereby providing a means to achieve process stability even under high organic loading conditions in co-digestions. Moreover, the availability of biochar-enriched digestate with superior characteristics than biochar-free digestate adds further merit to this process.
KW - Anaerobic co-digestion
KW - Biochar properties
KW - Biochar-enriched digestate
KW - Food waste
KW - Syntrophic oxidation
KW - VFA mitigation
UR - http://www.scopus.com/inward/record.url?scp=85107090452&partnerID=8YFLogxK
U2 - 10.1016/j.jenvman.2021.112457
DO - 10.1016/j.jenvman.2021.112457
M3 - Journal article
C2 - 33895449
AN - SCOPUS:85107090452
SN - 0301-4797
VL - 290
JO - Journal of Environmental Management
JF - Journal of Environmental Management
M1 - 112457
ER -