Anaerobic biodigesters heating sources: Analysis and recommendations

Biogas is a sustainable energy source generated through Anaerobic Digestion (AD), a process where organic wastes are converted into biogas under specific conditions. The temperature has a substantial impact on the bacterial digestion process. Consequently, its variations should not exceed 2–3 °C per hour, or the biogas generation rate will fluctuate dramatically. Thus, a stable digestion temperature is needed. As a result, the biogas system should include a heating system that guarantees steady biogas production. In this study, the environmental, economic, agricultural, and social benefits of biodigesters are discussed. Then, different heating sources are analyzed to find the favorable method for each climatic region based on the type of bacteria used. In tropical areas, solar energy is effective, while geothermal energy is more suitable for colder regions. However, geothermal heating systems have high payback periods, while the payback period of solar energy systems can be decreased when combined with a biogas source or a greenhouse. The study also highlights the potential of incorporating phase-change materials in biodigester enclosures to minimize the required heating, thus maintaining optimal temperatures over prolonged periods.