title: Effects of shearing on biogas production and microbial community structure during anaerobic digestion with recuperative thickening.
abstract: Recuperative thickening can intensify anaerobic digestion to produce more biogas and potentially reduce biosolids odour. This study elucidates the effects of sludge shearing during the thickening process on the microbial community structure and its effect on biogas production. Medium shearing resulted in approximately 15% increase in biogas production. By contrast, excessive or high shearing led to a marked decrease in biogas production, possibly due to sludge disintegration and cell lysis. Microbial analysis using 16S rRNA gene amplicon sequencing showed that medium shearing increased the evenness and diversity of the microbial community in the anaerobic digester, which is consistent with the observed improved biogas production. By contrast, microbial diversity decreased under either excessive shearing or high shearing condition. In good agreement with the observed decrease in biogas production, the abundance of Bacteroidales and Syntrophobaterales (which are responsible for hydrolysis and acetogenesis) decreased due to high shearing during recuperative thickening.
authors.affiliation: Strategic Water Infrastructure Lab, School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia.
authors.forename: Shufan
authors.initials: S
authors.lastname: Yang
authors.affiliation: Strategic Water Infrastructure Lab, School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia.
authors.forename: Hop V
authors.initials: HV
authors.lastname: Phan
authors.affiliation: Sydney Water, Parramatta, NSW 2124, Australia.
authors.forename: Heriberto
authors.initials: H
authors.lastname: Bustamante
authors.affiliation: Centre for Technologies in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
authors.forename: Wenshan
authors.initials: W
authors.lastname: Guo
authors.affiliation: Centre for Technologies in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
authors.forename: Hao H
authors.initials: HH
authors.lastname: Ngo
authors.affiliation: Strategic Water Infrastructure Lab, School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia. Electronic address: longn@uow.edu.au.
authors.forename: Long D
authors.initials: LD
authors.lastname: Nghiem
mesh_terms: D000693:Anaerobiosis; D041963:Bacteroidetes / Q000235:genetics* / Q000378:metabolism; D056804:Biofuels / Q000032:analysis; D019149:Bioreactors / Q000382:microbiology; D064307:Microbiota / Q000235:genetics; D058889:Molecular Typing; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry / Q000382:microbiology
chemical_list: D056804:Biofuels; D012336:RNA, Ribosomal, 16S; D012722:Sewage
keywords: 16S rRNA sequencing; Anaerobic digestion; Biogas production; Microbial community structure; Recuperative thickening