Abstract:
Low-income countries (LICs) have long benefitted from household biogas plants for the extraction of clean energy and fertilizers. Despite their popularity, such ordinary plants do not have heating systems and suffer from low biogas production in cold regions or during winter. This paper presents a comprehensive review of the research and development of household biogas technology in cold climates. This review specifically highlights the influence of temperature on biogas production and technologies, as well as recent advances in psychrophilic biogas production. These measures include the introduction of adapted inocula, maneuvering operational parameters (such as hydraulic retention time and organic loading rate), co-digestion approach and additives, and digester designs. In addition, this review shows that the adoption of low-cost heating arrangements, including the construction of a greenhouse over biodigesters, digester insulation, and integration of solar heating, is crucial for enhancing biogas production. Furthermore, this review identified gaps in the operation of biodigesters under psychrophilic temperature in LICs and recommends operational consistencies in full-scale psychrophilic biogas plants through the development of standards, operational guidelines, and user training.