The yield of biogas produced by mid-temperature (35℃±1℃) anaerobic fermentation of rice hulls was investigated

and material and energy flows as well as the distribution of element C and N during this fermentation process were also analyzed using the material flow analysis (MFA) method in this paper. The results showed that during the fermenting rice hulls to prepare biogas

the production rates for biogas and for CH4 were 297.41 and 164.40 ml·(gVSRH)-1

respectively; implying that average CH4 content in biogas was 55.28%

corresponding to 31.16% of the theoretical yield. Based on MFA for the fermentation process system

30.8% and 6.4% of C element were converted into biogas and slurry

and 62.9% left in residue

separately; 63.2% of N element were converted into slurry and 36.8% left in residue

while negligible N element was in biogas. The efficiencies of material and energy for conversion of rice hulls to biogas were 30.0% and 33.7%

respectively. This study could be as a theoretical basis for resource management and energy utilization of agricultural wastes.