Anaerobic Co-digestion of Kitchen Waste and Cattle Manure for Methane Production

Anaerobic co-digestion of kitchen waste and cattle manure was carried out in laboratory scale in batch and semi-continuous modes under mesophilic temperature. Five feedstocks of R1, R2, R3, R4, and R5 were tested, which were made by mixing kitchen waste with cow manure at different mixing ratios of 0:1, 1:1, 2:1, 3:1, and 1:0, respectively. The results showed that 61.0–85.2% of specific methane potential of R2–R4 were contributed by the addition of kitchen waste, which exhibited the highest specific methane potential and biodegradability in batch test. In semi-continuous operation, the methane yield in the digestion of kitchen waste as sole feedstock was 8.8–37.8% less than that of R2–R4. The highest methane yield of 233 ml/g volatile solid was obtained at the mixing ratio of 3:1; therefore, the mixing ratio of 3:1 is recommended as the optimal one for the co-digestion of kitchen waste and cow manure.