Effects of vinasse and silica mud on the performance of thermophilic fermentation of brewery sludge from brewery waste substrates

The anaerobic digestion of mixing brewery sludge with vinasse and silica mud at various ratios under thermophilic conditions was explored. Vinasse, silica mud and beer sludge (the sludge from the treatment of beer wastewater) are the main solid wastes of the beer production. Uncontrolled decom-position of these wastes could cause large-scale contamination of soil, water, and air. The results of the investigation showed that the optimal ratio of beer sludge and vinasse was 1:1 under total solids of 10%, producing the highest amount of gas of 1.34 cm³/g within 24 h and 4.06 cm³/g in 10 days. The silica mud weakened the fermentation process and reduced the gas production, and the concentration of total organic carbon, total nitrogen and volatile solids decreased during the digestion. For the mixture of brewery sludge and vinasse, the content of the total organic matter in the biogas manure was more than 60% and the value of pH was 6.5 after the anaerobic digestion, indicating that the manure can be used as an organic fertilizer.