Agro-Waste from A Local South African Market: Characteristics and Co-Digestion Biogas Application

Abstract

The demand for fruits and vegetables has increased recently, and the market is expanding because of population growth, particularly in South Africa. The increase in the production and supply of fruits and vegetables is adding to the threat to the environment by producing large amounts of agro-waste (AW) that is produced. Therefore, there is an urgent need for proper management of AW from fruits and vegetables. In addressing the challenge of AW management, the current study focuses on the production of biogas by anaerobic co-digestion of AW (i.e., banana, tomatoes, oranges, and spinach) with market wastewater (MW). AW samples were characterised for surface area, elemental analysis, functional groups, ash and moisture content, total solids, and volatile solids, and to find the potential of the substrate in the production of biogas. The characterisation resulted in a surface area of 0.92 to 1.7 m 2 /g; functional groups of alkyl aryl ether, alcohols, aromatic chains, and cyclic alkene defined; ash content of 0.28 to 2%; and volatile solids of 75 to 85 %. The model AWs for the current study were found to be ideal feedstock with properties to produce biogas of 600 mL/day on average.