Household biogas technology in cold climate of low-income countries: A review on sustainable technologies for accelerating biogas generation

Low-income countries have long benefited from household biogas plants for extracting clean energy and fertilizer. Despite the popularity, such ordinary plants do not have heating systems and suffer lower biogas production in cold regions or cold winters. This paper attempts a comprehensive review on research and development of household biogas technology in cold climate. This review specifically highlights the influence of temperature on biogas production, and technologies and recent advances in psychrophilic biogas production. Such measures are introduction of adapted inoculums, maneuvering operational parameters like hydraulic retention time (HRT) and organic loading rate (OLR), co-digestion approach and additives and digester designs. In addition to that, the review portrays adoption of low-cost heating arrangements including construction of greenhouse over bio-digesters, digester insulation, and integration of solar heating is crucial to enhance biogas production. Furthermore, this review identified gaps in the operation of bio-digesters under psychrophilic temperature in low-income countries and recommends operational consistencies in full scale psychrophilic biogas plants through development of standards, operational guidelines, and users' trainings.