Anaerobic co-digestion of surplus yeast and wastewater to increase energy recovery in breweries

• Published in: Water science and technology Vol. 61; no. 5; pp. 1129 - 1135
• Main Authors: Neira, K, Jeison, D
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01-01-2010
• Subjects: Alternative energy sources; Anaerobic digestion; Anaerobiosis; Beer; Biofuels; Biogas; Bioreactors; Breweries; Brewing industry wastewaters; Digestion; Economic conditions; Energy recovery; Feasibility; Feasibility studies; Industrial Waste; Methane - chemistry; Organic matter; Oxygen - chemistry; Reactors; Renewable energy; Sewage - chemistry; Sludge; Suspended particulate matter; Suspended solids; Temperature; Time Factors; Upflow anaerobic sludge blanket reactors; Waste Disposal, Fluid - methods; Waste Management - methods; Wastewater; Wastewater treatment; Water Pollutants, Chemical - analysis; Water Purification - methods; Yeast; Yeasts
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2010.052

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.