Biohydrogen produced through dark fermentation is currently gaining
importance as biofuel of the future and a potential replacement of fossil fuels.
However, low conversion efficiency of substrate into hydrogen and unstable
hydrogen production during continuous operation mode are limiting largescale
industrial production. Doctoral dissertation was therefore assessing
different techniques in order to enhance the efficiency of fermentative
hydrogen production with degradation of readily biodegradable organic
substrates. We have found out, that numerous environmental factors are
influencing hydrogen production, as well as different inoculum pretreatment
methods. Highest hydrogen yield (2.04±0.11 mol H2/mol glucose) was
achieved in case of thermal pretreatment on 80 °C for 2 h, at inoculum age of
1 day, incubation temperature of 37 °C, organic loading of 5 g OMglucose/L and
mixing intensity with Reynolds number of 500. Previous studies have focused
primarily on the operation in the pH range of 5.0-7.0, while there are less
studies for low pH conditions, which would be however technical and
economic advantage. Our results successfully demonstrated stable dark
fermentation process in plug flow reactor filled with different support
materials (Mutag BioChipTM, expanded clay and activated carbon) at acidic
pH value (4.0±0.2) and glucose as substrate. Obtained hydrogen yields in
reactors filled with Mutag BioChipTM, expanded clay and activated carbon
were 1.80±0.07, 1.74±0.10 and 1.46±0.09 mol H2/mol glucose, respectively.
High yield and stable hydrogen production at low pH value and activated
carbon as support material for immobilization was achieved also with the use
of food waste (168.5 NmL H2/g OM). With achieved stable hydrogen
production process throughout the operation period at low pH values, we
proposed a novel strategy that could contribute to the reduction of financial as
well as environmental costs.
|
