Development and application of prefabricated biogas digesters in developing countries

Biogas technology has been promoted worldwide over the past decades, and its use has led to the recognition of the many benefits of domestic biogas digesters. Prefabricated biogas digesters (PBDs) continue to be developed, tested, and extensively applied in developing countries to compensate for the disadvantages of traditional domestic digester models. PBD prototypes are derived from three major types of domestic digester models, namely, the fixed dome, floating drum, and plug flow digesters. Two main streams of PBDs are represented by composite material digesters (CMDs) and bag digesters. PBDs also include off-site constructed ferro- or bamboo-and-cement digesters, as well as assembled digesters. The advantages of PBDs promote the development of different types of PBDs, and several nations have set up special instructions and institutions to promote PBDs. Challenges to PBD dissemination include inferior quality, high investment in CMDs, lagging PBD standardization, low levels of public information about PBDs, and lack of follow-up services. However, based on our literature research and field visits, it could be predicted that PBD technologies will be extensively applied worldwide in the near future.