The present work on the production of biogas from cow dung substrates was carried out at the Laboratory of Renewable Thermal Energy (L.E.T.RE) of the Joseph KI-ZERBO University in collaboration with the National Program of Biodigester of Burkina Faso (PNB-BF). We focus in this work on the determination of the physicochemical characteristics of the substrates allowing the follow-up of the biogas production. We experimented with anaerobic digestion for 100 days each at mesophilic temperature, i.e. a hermetic enclosure included between 27 and 38◦C. The average flow of biogas is Q = 2:5 m3d−1, and that of methane is 1:9 m3d−1. This methane-rich gas CH4 with a flow rate of 1:9 m3d−1, i.e. a rate of 60% in the biogas, has a high energy capacity of 23kJm−3 and can be used for cooking and lighting especially in rural areas. The following physicochemical characteristics were observed for cow dung: dry matter 11:85%, volatile matter 58:83%, hydrogen potential 7.01, density 731 kg:m−3, carbon content 33:32%, nitrogen content 1:46%, nitrogen-carbon ratio 24:70, acids are around 0:18 kgCODm−3, and the average chemical oxygen demand 30 kgCODm−3. This characterization was performed on a 4m3 pilot bioreactor with daily substrates loading ranging from 20 to 30 kg. The temperature of the reaction medium remained around 35◦C, optimal for the mesophilic operation of the bioreactor. The results obtained making it possible to demonstrate the possibility of producing a large quantity of flammable biogas in a continuous manner are in agreement with the literature on methanization.

Anaerobic digestion; characterization; cow substrates; biogas.