Manual for the construction and operation of small and medium size biogas systems

This manual is the result of the lessons learned of the ADPP biogas project in the province of Cabo Delgado, Mozambique. This manual has been prepared to support practitioners with the installation of small‐ and medium scale biogas systems. In particular, this manual will be used by ADPP to support the operation of their floating dome‐ and plug flow systems. The manual describes 2 digester types that can be installed by individuals with little or no background in biogas technology. It is intended for application in developing countries, in households or institutional setting. This manual starts with an introduction to biogas and the required conditions. Next, the planning of installations is discussed, followed by instructions on how to construct a plug flow system and a floating dome system. Subsequently, start‐up procedures, troubleshooting and maintenance, and gas transport and usage are discussed. The final chapter presents the cost‐benefit analysis of different system scenarios. It was concluded that plug flow systems show a considerable scale advantage with respect to investment costs and operational costs. Furthermore, replacing diesel in a diesel engine with biogas is the most feasible option in comparison with replacing LPG, fuelwood or charcoal.