Biogas production from cow dungs using a modified fixed-dome digester

A modified fixed dome digester with stirring mechanism has been designed and constructed and used for the anaerobic digestion of cow dung slurry at 5%-7% Total solid (TS) concentration within the mesophylic temperature range. The quality of biogas gas produced was between 54%-69% methane (CH4) content. The Carbon to Nitrogen ratio (C: N) varied between 35:1 - 45:1. Total biogas yield obtained over the detention period was about 261 L. The maximum and minimum temperatures recorded over the 95 days period was 32oC and 25 oC respectively. The volume of biogas yield, Vb (m3) was observed to increase with the percentage total solid, PTS (%). The details of the design and construction of the biogas digester plant and its cost are reported. The performance of the plant was very satisfactory. Investigation into the anaerobic digestion revealed that cow dung has great potentials for generation of biogas.