Bio-hydrogen And Methane Production From A Higher Concentration Of Maize Straw By Combining Dark Fermentation And Anaerobic Digestion

In this paper, the high concentration of corn stalk (60g/L) was employed asfeedstock to produce bio-hydrogen and methane by combining hydrogen fermentationand anaerobic digestion. In the first stage of hydrogen fermentation, the effects ofseveral key parameters, such as strain enhancement technique, cetyl trimethylammonium bromide (CTAB), NH4HCO3on hydrogen production from cornstalk wereinvestigated and optimized. The maximum hydrogen yield of79.8ml H2/g-TS andhydrogen production rate of3.78ml/g-cornstalk h was observed at fixed acidizingcornstalk of60g/L, strains Bacillus sp. FS2011dosage of10%(v/v), CTAB of30mg/L, NH4HCO3of1.2g/L and initial pH of7.5±0.5at36±1°C, respectively. In thesecond stage of anaerobic digestion, the effluent from hydrogen productionbio-reactor was further employed as the feedstock to produce methane bymethanogenic bacteria, the maximum methane yield of227±2.5ml CH4/g-COD andCOD removal rate of95±1%was recorded. The interesting observations were that thetotal amount of the organic wastewater produced in a higher substrate concentration(60g/l) by hydrogen fermentation was reduced by about two-thirds compared with thatof traditional low substrate concentration (≤20g/l).Two pH control strategy have been developed to enhance the hydrogen productionfrom high-concentration of corn stalk on the basis of the above results. The resultsindicated that the maximum hydrogen yield of97.21ml H2/g-corn stalk was obtainedin strategy1, which was increased by13.44%compared with that of the control group,in which, the plateau phase was disappeared and the proportion of acetate content inthe VFAs was increased throughout the hydrogen fermentation process.