Design and sustainability of a biogas plant for domestic use

This paper presents a study on the design methodology of domestic mechanical anaerobic digesters. The energy crisis in Africa and especially in Southern Africa has raised concerns over the effects of depleting fossil fuel reserves. With recent improvement in biogas technology; development, implementation and commercialization of prefabricated plants for biogas production has led to the recognition of the benefits resulting from domestic bio digester plant use. Global efforts have been made in building and developing domestic biogas plants, but the lack of literature on design considerations for optimum development makes this challenging. Design parameters were studied through field surveys and literature reviewed on biogas technology. With relevant information, a domestic anaerobic digester was designed using a design process that consists of determining gas requirements, biomass selection and yield potentials, sizing the digester and design of additional components such as heating and mixing elements. Using a continuous digester system led to concluding that the organic loading rate, hydraulic retention time and type of waste to be processed play a major role in the design process of such systems.