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. ...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（167 L/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 135 LCH4/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（0.269 day-1and 0.245 day-1） and methane production（135 versus 149 L/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.展开更多
文摘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（167 L/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 135 LCH4/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（0.269 day-1and 0.245 day-1） and methane production（135 versus 149 L/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.
