Design, construction and mathematical modelling of the performance of a biogas digester for a family in the Eastern Cape province, South Africa

Abstract

Currently, South Africa is experiencing electricity blackouts as result of an energy shortage. Biogas can be a solution to South Africa’s energy needs, especially in the rural areas of the Eastern Cape province that have plenty of biogas substrates from cattle, donkeys, goats, sheep and chicken. The purpose of this paper is to design and construct a 1 m3 family biogas digester and model its performance using donkey dung as a biogas substrate. The installation of this type digester in rural communities of South Africa has economic, social and environmental advantages. The digestate from the digester is a valuable soil fertilizer, rich in nitrogen, phosphorus, potassium and micronutrients, which can be applied on soils. The mathematical model equation developed is highly beneficial in the rural areas of the Eastern Cape province of South Africa where many donkeys are kept. Currently, no mathematical models have been developed for optimum methane yield from the named substrate.