Anaerobic co-digestion of surplus yeast and wastewater to increase energy recovery in breweries.
Surplus yeast is a residue produced during brewery process, which presents high contents of organic matter. Biogas production from yeast could significantly contribute to bioenergy production in breweries, via biogas generation. Co-digestion of surplus yeast and brewery wastewater in a single treatment step would simplify the technical and economical requirements for the transformation of both residues into biogas. The feasibility of such co-digestion process was studied by means of batch tests and a lab-scale UASB reactor operation. The effect of applying three pre-treatments (thermal, chemical and mechanical) to the surplus yeast was also studied. Results showed that co-digestion of yeast and brewery wastewater is feasible, since no negative effects of the joint digestion were observed. Pre-treatments tested in this research produced no significant improvements on biogas yield or digestion rates. Even though no negative effects were observed when digesting wastewater and yeast in a UASB reactor after 70 days, long-term studies would be needed in order to detect potential negative effects over granular sludge development, sometimes observed during the treatment of some wastewaters containing suspended solids.
Neira
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K
Chemical Engineering Department, Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco, Chile.
Jeison
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D
D000693:Anaerobiosis; D001515:Beer; D056804:Biofuels; D019149:Bioreactors; D007220:Industrial Waste; D008697:Methane / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D012722:Sewage / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D018505:Waste Management / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods*; D015003:Yeasts
D056804:Biofuels; D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical; D008697:Methane; D010100:Oxygen