title: Anaerobic co-digestion of excess brewery yeast in a granular biomass reactor to enhance the production of biomethane.
abstract: The anaerobic co-digestion of brewery yeast using granular biomass was studied on the lab, pilot and full-scale. The study shows no adverse effects in the co-digestion of yeast and wastewater in concentrations up to 1.1 (v/v)%. In concentrations up to 2.3% the process is manageable; however, not advisable. In concentrations over 2.8% the process exhibits failure due to the overload with suspended solids. An average specific biogas production of 0.560 m(3)kg(-1) of volatile solids was achieved. Full-scale operation with 0.7% yeast concentration showed a 38.5% increase in the biogas production and a 26.2% increase in the organic loading rate, which resulted in an increase of the biomethane/natural-gas substitute ratio from 10% to 16%. The influence of the yeast addition on the structure of the microbial biomass showed up to 7% dissimilarity in the archaeal and a 32% dissimilarity in the bacterial biomass community, which did not present any difficulties.
authors.affiliation: National Institute of Chemistry, Laboratory for Environmental Sciences and Engineering, Ljubljana, Slovenia. gregor.zupancic@ios.si
authors.forename: Gregor D
authors.initials: GD
authors.lastname: Zupančič
authors.forename: Igor
authors.initials: I
authors.lastname: Skrjanec
authors.forename: Romana Marinšek
authors.initials: RM
authors.lastname: Logar
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D019149:Bioreactors; D008697:Methane / Q000378:metabolism*; D010865:Pilot Projects; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D008697:Methane