Pilot Production of Biogas from Vegetable Waste for Energy Self-Sufficiency in Households in Ouagadougou Peri-Urban Area, Burkina Faso

Abstract

Inadequate solid waste management, particularly organic waste from markets, represents a major environmental and health challenge at Ouagadougou in Burkina Faso. The aim of the study was to produce biogas from plant waste to achieve energy self-sufficiency in the Burkina Ouagadougou peri-urban areas. The methodology involves the collection and physicochemical characterization of vegetable waste. A 200-liter pilot biodigester equipped with a meter, a biogas storage chamber, and a stove designed by the Albert Schweitzer International Centre (CEAS) was used for the tests. Anaerobic digestion was carried out, including an acclimatization phase with cow manure alone, followed by the addition of different proportions of substrate (1/3, 1/2, and 3/4 after 24 hours of pre-fermentation). Anaerobic digestion was monitored in terms of the volume of biogas produced, its composition (CH 4 , CO 2 , H 2 S), and changes in the pH and volatile fatty acids (VFA) of the digestate. The results of the physicochemical parameters show average contents of dry matter (DM) and volatile dry matter (VDM) of 6.20% and 78.88%, respectively. A C/N ratio of 5.47 was obtained, indicating an ideal substrate for biogas production. Cow manure alone generates the highest average volume of biogas (7.42 dm 3 /day), but co-digestion with vegetable waste significantly improves the quality of the biogas. An overall assessment of the digester’s performance shows good energy yield. The digestate pH remains stable (7.31 - 7.50), and H 2 S levels are low (peaking at 37 ppm). Therefore, the technology is technically reliable, but its long-term productivity depends on proper operational management, particularly substrate supply.