Hydrogen production from beverage wastewater via dark fermentation and room-temperature methane reforming

Direct and indirect bio-hydrogen generation via mesophilic (35 degrees C) dark fermentation and room-temperature (25 degrees C) methane reforming, respectively, were studied to maximize bio-hydrogen production from a wastewater in an environment-friendly way. In lab-scale dark fermentation, beverage wastewater substrate was used for bio-hydrogen production and its effluent was fed into a bio-methane producing reactor. In methane reforming, a lab made plasma-assisted methane-reformer using a steel-silk catalyst was used. A peak hydrogen production rate (HPR) of 20 L H-2/L-d was obtained at hydraulic retention time (HRT) 8 h, pH 5.6 and substrate concentration 40 g total sugar/L. A peak methane production rate of 12 L CH4/L-d was obtained for the methane-fermenter fed on the hydrogen-fermenter effluent with an influent beverage wastewater concentration of 30 g total sugar/L. The methane reforming had a methane conversion rate of 12.7% and an HPR of 132 L H-2/L-d. The hydrogen gas produced from both direct and indirect ways did not contain CO. Moreover, the present reforming method had an efficiency of 0.0048 L/min-W indicating it is comparable to other methods. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.