Abstract
The continuous two-stage thermophilic-mesophilic hythane fermentation of cassava residue with recirculation was conducted over 250 days, to demonstrate start-up strategy by shorting HRT in methanogenic stage, and to investigate nickel, cobalt and sulfur affection on hythane fermentation. Shorten HRT of methane-stage from 80 days to 12 days and maintaining HRT of hydrogen under 3 days was a quick strategy for hythane start-up process. The hythane fermentation of cassava residue under continuous operation without the addition of nutrients resulted in an unstable performance for long-term operation, which was characterized by a radical decrease in the methane production along with a drop in the methane content. The effects of adding Co2+ and Ni2+, S0 and SO42- were discussed in this study. The results of nutrients affection demonstrated the sufficient addition of nutrients could recover and enhance hythane fermentation effectively.
