Biogas digester types installed in South Africa: A review

This narrative review paper begins with a brief history of biogas digesters in South Africa followed by a listing of the biogas digesters that have been installed in the country then the critical analyses of the different types of small scale biogas digesters since the introduction of the biogas technology into the country in the year 1957. The analysis is done on a basis of conducted studies and observations of the strengths and limitations of each small scale digester design installed. It is the aim of the review to help stakeholders in the selection of the most appropriate digester type well suited to their environmental conditions and to fill the knowledge gap existing in the biogas technology and hence making it easier to map of a way forward into the design of improved anaerobic digesters. In this review, the in-situ cast concrete digester has been analyzed to be the most suitable design for installation in the South African context though stakeholders can still do their own selection based on the analyses of the other designs. Some recommendations of aspects to consider in the introduction of a new design are also given.