A review of prefabricated biogas digesters in China

China plays a leading role in the worldwide development and dissemination of household-based biogas technology. Since the 1980s, China has developed many types of commercialized or half-commercialized prefabricated biogas digesters (PBDs), which are categorized into three: glass fiber-reinforced plastic digesters, plastic soft digesters, and plastic hard digesters. This paper summarizes the development of PBDs in China, including their key characteristics, manufacturing process, advantages and disadvantages, cost analysis, marketing, and future prospects. Furthermore, the paper highlights and analyzes potential constraints in the promotion of these types of digesters; examples of these constraints include incomplete standardization systems, insufficient demonstration projects, low-quality digesters, and missing authorizations from the inspection department. A preferential policy should be formulated for the prefabricated digester industry. Specifically, the standardization system should be improved, technological innovations should be encouraged, self-regulation of the industry should be intensified, demonstration projects should be implemented, and follow-up services should be improved. PBD technologies can potentially be applied with great reliability and high efficiency not only in China but also in other countries.