INVESTIGATION OF BIO-HYDROGEN AND BIO-METHANE PRODUCTION FROM POTATO WASTE

An evaluation of single-stage and two-stage anaerobic digestion processes for biomethane and biohydrogen production using potato waste was performed to assess the viability of biohydrogen production from potato waste and the impact of separating the acidogenic and methanogenic stages on anaerobic digestion with hydrogen production in the first stage. Potato waste has the potential to improve hydrogen production with a maximum yield of 0.51 LH2/g CODconsumed with anaerobic digester sludge (ADS). A comparison of the initial substrate-to-biomass So/Xo of 0.5 and 1 g CODsubstrate/g VSSseed demonstrates that the optimum experimental range of So/Xo for hydrogen production is 0.5 g CODsubstrate/g VSSseed using anaerobic digester sludge ADS. The optimum experimental range of So/Xo for methane production is o.5 g CODsubstrate/g VSSseed using ADS as a seed and supernatant as a feed. However, when using mixed substrate, there is not a significant difference between different So/Xo. Potato waste has the potential to improve methane production with a yield of 0.39 m3CH4/kg TCODremoved when using supernatant as a feed as tests with mixed feed only revealed a maximum potential of 0.35 m3CH4/kg TCODremoved. In this research, the use of two-stage digestion for potato waste led to an increase in the TVFAs to TCOD ratio due to the acidification process during hydrogen production in the first stage. The methane yield in the anaerobic digestion stage increased from 0.29 m3CH4/kg TCODremoved in the single-stage process to 0.39 m3CH4/kg TCODremoved in the two-stage and single-stage processes, respectively