Timing of biochar dosage for anaerobic digestion treating municipal leachate: Altered conversion pathways of volatile fatty acids

To-Hung Tsui; Le Zhang; Ee Yang Lim; Jonathan T E Lee; Yen Wah Tong

doi:10.1016/j.biortech.2021.125283

Timing of biochar dosage for anaerobic digestion treating municipal leachate: Altered conversion pathways of volatile fatty acids

Bioresour Technol. 2021 Sep:335:125283. doi: 10.1016/j.biortech.2021.125283. Epub 2021 May 15.

Authors

To-Hung Tsui¹, Le Zhang¹, Ee Yang Lim², Jonathan T E Lee¹, Yen Wah Tong³

Affiliations

¹ NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE) 1 CREATE Way, Singapore 138602, Singapore.
² Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
³ NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE) 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore. Electronic address: chetyw@nus.edu.sg.

PMID: 34015564
DOI: 10.1016/j.biortech.2021.125283

Abstract

In this study, the anaerobic digestion (AD) applications of early & late biochar dosage were compared for municipal leachate treatment, with the objective of studying the flexible use of biochar as a mitigation measure for biomethane recovery. In two experimental phases, biochar was favourable for the immediate promotion of AD performances, as revealed by Gompertz's model of reduced lag phases, higher biomethane generation rates, and increased biomethane yields. Irrespective of late biochar dosage, it could still retrieve 89% of the ultimate biomethane potential. Comparing the residual VFAs (volatile fatty acids) compositions, it was found that the fraction of long-chain VFAs accounted for 81% of total VFAs in reactor set of early biochar dosage, while it was only 38% in the reactor of late one. Parallel evidence suggested that the schedule of biochar dosage not only could affect methanogenic responses but also the VFAs conversion pathways.

Keywords: Biochar; Chain elongation; Direct interspecies electron transfer; Leachate; Volatile fatty acids.

MeSH terms

Anaerobiosis
Bioreactors*
Charcoal
Fatty Acids, Volatile
Methane*

Substances

Fatty Acids, Volatile
biochar
Charcoal
Methane