Two dry anaerobic digestions of kitchen waste and cow manure were conducted in a lab-scale experiment for investigating the start-up performances under mesophilic and thermophilic conditions. According to cumulative biogas production (CBP), biogas production rate (BPR), pH value and VFAs variation, the start-up performances were separated into 3 stages- adaption stage, fluctuation stage and stabilization stage. The effective start-up of the system proceeded for approximately 140 days (55 days for adaption and fluctuation stage and 85 days to reach suitable conditions and stabilize the main operational parameters at hydraulic retention times (HRT) for 20 days). During these start-up performances, CBPs are 1070.5 and 1289.1 L respectively, and the average concentrations of CH4 in biogas are 52.9% and 56.1% respectively. The final NH4+-N concentrations are 1897 and 1999 mg/L under mesophilic and thermophilic conditions, respectively. Thermophilic digestion was more efficient than mesophilic.
Kitchen waste, Cow manure, Anaerobic digestion, Start-up
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