Producing Hydrogen in Sequential Dark and Photofermentation from Four Different Distillery Wastewaters

摘要

Four different distillery wastewaters were applied as the substrates for dark and photofermentation - wheat stillage (WTL), wheat syrup (WSR), maize stillage (MTL) and maize syrups (MSR). WTL was found to be the most effective substrate in dark fermentation, with a hydrogen production of 0.88 L H-2/L-medium and a yield of 1.17 L H-2/L-WTL. In the photofermentation experiments, the highest hydrogen production (1.7 L H-2/L-medium) and the highest yield (8.6 L H-2/L-WSR) were obtained with WSR as the substrate. A sequential two-step treatment, comprising dark fermentation followed by photofermentation, was applied to the same four substrates. WTL and MTL were the substrates for dark fermentation and the effluent after 5-fold dilution was used as the substrate in photofermentation. The maximum hydrogen production in the two-step system was 4.47 L H-2/LWTL-. Simultaneously, the organic compounds from the waste and those formed in dark fermentation were completely utilized, except for ethanol and methanol, which were 19% and 10% utilized, respectively.