title: Anaerobic mesophilic co-digestion of ensiled sorghum, cheese whey and liquid cow manure in a two-stage CSTR system: Effect of hydraulic retention time.
abstract: The aim of this study was to investigate the effect of hydraulic retention time (HRT) on hydrogen and methane production using a two-stage anaerobic process. Two continuously stirred tank reactors (CSTRs) were used under mesophilic conditions (37°C) in order to enhance acidogenesis and methanogenesis. A mixture of pretreated ensiled sorghum, cheese whey and liquid cow manure (55:40:5, v/v/v) was used. The acidogenic reactor was operated at six different HRTs of 5, 3, 2, 1, 0.75 and 0.5d, under controlled pH5.5, whereas the methanogenic reactor was operated at three HRTs of 24, 16 and 12d. The maximum H2 productivity (2.14L/LRd) and maximum H2 yield (0.70mol H2/mol carbohydrates consumed) were observed at 0.5d HRT. On the other hand, the maximum CH4 production rate of 0.90L/LRd was achieved at HRT of 16d, whereas at lower HRT the process appeared to be inhibited and/or overloaded.
authors.affiliation: Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, Greece.
authors.forename: Margarita Andreas
authors.initials: MA
authors.lastname: Dareioti
authors.affiliation: Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, Greece. Electronic address: kornaros@chemeng.upatras.gr.
authors.forename: Michael
authors.initials: M
authors.lastname: Kornaros
mesh_terms: D000383:Agriculture; D000693:Anaerobiosis; D000818:Animals; D019149:Bioreactors; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D002417:Cattle; D002611:Cheese; D005260:Female; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008372:Manure; D008697:Methane / Q000096:biosynthesis; D012820:Silage; D045868:Sorghum / Q000378:metabolism*; D018505:Waste Management / Q000295:instrumentation / Q000379:methods*; D000067796:Whey / Q000378:metabolism*
chemical_list: D007220:Industrial Waste; D008372:Manure; D006859:Hydrogen; D008697:Methane
keywords: Agro-industrial wastewaters; Anaerobic digestion; Ensiled sorghum; Hydraulic retention time; Two-stage system