title: Effect of hydraulic retention time (HRT) on the anaerobic co-digestion of agro-industrial wastes in a two-stage CSTR system.
abstract: A two-stage anaerobic digestion system consisting of two continuously stirred tank reactors (CSTRs) operating at mesophilic conditions (37°C) were used to investigate the effect of hydraulic retention time (HRT) on hydrogen and methane production. The acidogenic reactor was fed with a mixture consisting of olive mill wastewater, cheese whey and liquid cow manure (in a ratio 55:40:5, v/v/v) and operated at five different HRTs (5, 3, 2, 1 and 0.75 d) aiming to evaluate hydrogen productivity and operational stability. The highest system efficiency was achieved at HRT 0.75 d with a maximum hydrogen production rate of 1.72 L/LRd and hydrogen yield of 0.54 mol H2/mol carbohydrates consumed. The methanogenic reactor was operated at HRTs 20 and 25 d with better stability observed at HRT 25 d, whereas accumulation of volatile fatty acids took place at HRT 20 d. The methane production rate at the steady state of HRT 25 d reached 0.33 L CH4/LRd.
authors.affiliation: Chemical Engineering Department, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, Greece.
authors.forename: Margarita Andreas
authors.initials: MA
authors.lastname: Dareioti
authors.affiliation: Chemical Engineering Department, 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: D000143:Acids / Q000494:pharmacology; D000383:Agriculture; D000693:Anaerobiosis; D000818:Animals; D061249:Batch Cell Culture Techniques; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002241:Carbohydrates / Q000032:analysis; D002417:Cattle; D005232:Fatty Acids, Volatile / Q000032:analysis; D006859:Hydrogen / Q000378:metabolism; D007220:Industrial Waste / Q000032:analysis*; D019344:Lactic Acid / Q000032:analysis; D008697:Methane / Q000096:biosynthesis; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D012995:Solubility; D013997:Time Factors; D062065:Wastewater / Q000737:chemistry
chemical_list: D000143:Acids; D056804:Biofuels; D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D006859:Hydrogen; D007220:Industrial Waste; D019344:Lactic Acid; D008697:Methane; D062065:Wastewater
keywords: Agro-industrial wastewaters; Anaerobic digestion; Bio-hydrogen; Hydraulic retention time; Two-stage system