Broadening the potential of biogas in Sub-Saharan Africa: An assessment of feasible technologies and feedstocks

This paper aims to provide a broad review and assessment of the feedstocks and applicable biogas technologies that are feasible in Sub-Saharan Africa (SSA). Biodigesters and feedstocks available in SSA were identified according to scale and application – household, community, institutional, and commercial. Aside from livestock manure, suitable feedstocks for household, community, and institutional biodigesters include crop residues, night soil/domestic sewage, and the organic fraction of municipal solid waste (OFMSW). Significant untapped feedstocks exist from SSA agro-processing and food production industries. Biodigesters available in SSA for household, community, and institutional installations include variations of fixed dome, plug flow, and floating cover digesters. Commercial digester designs applicable to the region include continuously stirred tank reactors and fixed film digesters. The key factors that need to be considered in selecting suitable biodigester designs for specific applications include: feedstock availability, water supply, energy demand, local materials and labour, and the level of commitment to operate and maintain the biodigester effectively.