Thermophilic Digestion Process without External Dilution Water for Food Factory Waste that Consists Mainly of Coffee Grounds

• Published in: Journal of the Japan Society of Waste Management Experts Vol. 19; no. 1; pp. 51 - 60
• Main Authors: Tsuno, Hiroshi, Kadoshin, Shiro, Tsubota, Jun
• Format: Journal Article
• Language: Japanese
• Published: Japan Society of Material Cycles and Waste Management 2008
• Subjects: coffee grounds; hydrolysis; hyperthermal; two phase anaerobic digestion system
• ISSN: 1883-1648; 1883-163X
• DOI: 10.3985/jswme.19.51

The effect of the combination of hyperthermophilic hydrolysis and ammonia stripping on thermophilic anaerobic digestion was evaluated by a continuous experiment using a 2-litter reactor system. As a result, methane yield was increased by 20% and digestion residue was reduced by 50%. Ammonia stripping conditions in the hyperthermophilic hydrolysis reactor at 80°C and pH 7.5 was shown to keep ammonia concentration in the digester at 1000mg/L or less. The low concentration of ammonia allows the digester effluent to be used as a substitution for dilution water. Improved gasification efficiency also reduces the organic load on the subsequent effluent treatment process by 50%.