title: Using cheese whey for hydrogen and methane generation in a two-stage continuous process with alternative pH controlling approaches.
abstract: This study focuses on the exploitation of cheese whey as a source for hydrogen and methane, in a two-stage continuous process. Mesophilic fermentative hydrogen production from undiluted cheese whey was investigated at a hydraulic retention time (HRT) of 24 h. Alkalinity addition (NaHCO(3)) or an automatic pH controller were used, to maintain the pH culture at a constant value of 5.2. The hydrogen production rate was 2.9+/-0.2 L/Lreactor/d, while the yield of hydrogen produced was approximately 0.78+/-0.05 mol H(2)/mol glucose consumed, with alkalinity addition, while the respective values when using pH control were 1.9+/-0.1 L/Lreactor/d and 0.61+/-0.04 mol H(2)/mol glucose consumed. The corresponding yields of hydrogen produced were 2.9 L of H(2)/L cheese whey and 1.9 L of H(2)/L cheese whey, respectively. The effluent from the hydrogenogenic reactor was further digested to biogas in a continuous mesophilic anaerobic bioreactor. The anaerobic digester was operated at an HRT of 20 d and produced approximately 1L CH(4)/d, corresponding to a yield of 6.7 L CH(4)/L of influent. The chemical oxygen demand (COD) elimination reached 95.3% demonstrating that cheese whey could be efficiently used for hydrogen and methane production, in a two-stage process.
authors.affiliation: Department of Chemical Engineering, University of Patras, 1 Karatheodori st., 26500 Patras, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Venetsaneas
authors.forename: Georgia
authors.initials: G
authors.lastname: Antonopoulou
authors.forename: Katerina
authors.initials: K
authors.lastname: Stamatelatou
authors.forename: Michael
authors.initials: M
authors.lastname: Kornaros
authors.forename: Gerasimos
authors.initials: G
authors.lastname: Lyberatos
mesh_terms: D002611:Cheese; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000096:biosynthesis*; D008894:Milk Proteins; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins; D006859:Hydrogen; D008697:Methane