Biogas Production from Cow Manure in an Experimental 20 m3 Reactor with a Jet Mixing System

Biogas was generated from cow manure in a experimental 20 m3 reactor with a jet mixing system at a temperature of 35°C. The initial concentration of TS was 5%. Several parameters was investigated to elucidate the variation law of some critical indicators in the experimental biogas systems in batch fermentation process, such as biogas production rate, biogas composition, pH, COD and VFAs concentration. It was found that the biogas production was above 0.3 m3/ kg TS under mesophilic temperature conditions, and the total biogas produced was 108 m3. The methane content in biogas was around 60% after 6 days of fermentation.COD decreased from 26,800mg/L to less than 10,000mg/L, of which 72% was converted to biogas. The concentration of VFAs decreased from 2.27g/L to around 0.8g/L, and value of the pH was stabilized between 7.36 and 7.53 after the 9th day. This anaerobic digestion system had many advantages over other conventional systems,such as stability operation, energy-saving and high substrate utilization rate, which means its application in biogas production is feasible.