Biogas is competitive, viable and generally sustainable energy resource due to abundant supply of cheap feedstock and availability of a wide range of biogas applications in heating, power generation, fuel, and raw material for further
processing and production of sustainable chemicals including hydrogen and carbon dioxide and biofuels. The capacity of biogas power has been growing rapidly for the past decade with global biogas generation capacity increasing from 65 GW in 2010 to 120 GW in 2019 representing a 90% growth. The study showed that digester design, operation and maintenance is a very important aspect of biogas energy and technology development. It was established that there are three basic digester designs i.e. fixed dome, floating dome and fixed dome with expansion chamber. The main challenges facing digesters is silting, poor serviceability and limited mixing ability. Design improvements suggested are manual and motorised mixing and provision of access manhole to facilitate maintenance and service without stopping the entire process.
Key words: Biogas applications; Biogas production; digester design; digester operations.