Contributing to energy self-sufficiency in rural areas: biogas production trial in a 200 L pilot digester

Abstract

In Burkina Faso, access to energy is limited, and people in rural areas make little use of modern fuels at high cost. This study contributes to increasing energy selfsufficiency and the security of energy supplies by providing means of local production. A technique recommended by the National Biodigester Programme (PNB-BF) 1 kg of dejection for 1 l of water was used in a pilot digester 200 l drum. The biogas was quantified by estimating the volume of the air chamber and the pressure of the gas space. The gaseous products (CO₂ and CH₄) were analysed using a gas chromatograph. Total aerobic mesophilic flora and coliforms were removed. The material balance was assessed on the basis of organic matter removal. A potential of 135.02 L Biogas. kg^-1 and 74.94 l CH₄. kg^-1 of fresh cattle dung was obtained. Biomethane increases and reaches 80 l d^-1 after 3 days of production. CO₂ decreases below 50 l d^-1 during anaerobic digestion. The methane percentage reached 80.79% on day 8.  Reductions of 1.1 log, 0.71 log and 0.1 log were observed in total aerobic mesophilic flora, total coliforms and faecal coliforms respectively, which may lead to hygienisation of the digestate. The material balance shows a dry matter and organic matter removal of 48.8% MS and 62.1% MSV, respectively. The high biomethane content and high organic matter and microbial removal rates indicate a highperformance system.