Methane Fermentation of Cattle Manure : Effects of Hydraulic Retention Time. Temperature and Substrate Concentration

Abstract

This study has been undertaken in order to improve yield of methane production by anaerobic fermentation of cattle manure. Optimization of hydraulic retention time and organic concentration substrate were evaluated at 37°C and 55°C. The study of cattle manure fermentation process as well as that of methane production yield showed that methanogenic fermentation of these organic wastes may be conducted at low hydraulic retention time without stressing the fermentary process : 8 days at 37°C and 5 days at 55°C for a dry matter concentration of 43 g/1. The biogas yield increased, reaching 0.46 m3/(m3. d) at 37°C and 0.68m3/(m3. d) at 55°C with a methane content of 56 %> and 51 %> respectively. The best biogas yields occurred for dry matter concentrations between 7 and 9 %>. Kinetic models of Chen and Hashimoto (7) and of Monod (19) described well substrate depletion and methane production.

Keywords

• Methane fermentation
• Cattle manure
• Hydraulic retention time
• Temperature
• Methane yield