title: High-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions.
abstract: The purpose of this study was to investigate the potential of high-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions, focusing on the effects of the strength and the amount of inoculum. Ensiled grass was inoculated with three different inocula; inoculum from liquid anaerobic digester (LI), inoculum from dry anaerobic digester (DI), and mixture of LI and DI (MI), at feedstock-to-inoculum ratio (FIR) of 1, 2 and 4. The ensiling process of riverbank grass reduced moisture content (p>0.05), while the hemicellulose content was significantly increased from 30.88% to 35.15% (p<0.05), on dry matter basis. The highest methane production was at an FIR of 2 with MI (167L/kg VSadded), which was significantly higher (p<0.05) than with DI, but not significant compared to LI (p>0.05). At an FIR of 4, digesters inoculated with LI and DI failed to produce methane, whereas 135LCH4/kg VSaddedwas obtained with MI. The kinetic studies showed that at an FIR of 1 with LI and MI, the inoculum had less of effects on the hydrolysis rate constant (0.269day-1and 0.245day-1) and methane production (135 versus 149L/kg VSadded); rather, it affected the lag phase. In a thermophilic HS-AD of riverbank grass, the mixture of inoculum with low and high total solids content (TS) helps increase the TS of inoculum and digestion process. An FIR of 2 was deducted to be the limit for a better startup time and higher volumetric productivity of methane.
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan. Electronic address: fetrajules@yahoo.fr.
authors.forename: Fetra J
authors.initials: FJ
authors.lastname: Andriamanohiarisoamanana
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matsunami
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Takaki
authors.initials: T
authors.lastname: Yamashiro
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Graduate School of Agriculture Science, Kobe University, Kobe 657-8501, Japan.
authors.forename: Ikko
authors.initials: I
authors.lastname: Ihara
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan. Electronic address: umetsu@obihiro.ac.jp.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Umetsu
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D007700:Kinetics; D008697:Methane; D006109:Poaceae; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D008697:Methane
keywords: Feedstock-to-inoculum ratio; High-solids anaerobic digestion; Inoculum; Riverbank grass; Thermophilic temperature