Analysis and Evaluation of a Three-Stage Anaerobic Digestion Plant for Management of Biodegradable Municipal Solid Waste

Abstract

Sub-Sahara Africa countries are faced with the problem of solid waste management and access to sustainable energy. There is a need to develop a technology that can help to manage the generated solid waste and the same time produce green energy that is sustainable. Hence, this research work that focused on the development of a novel three-stage anaerobic digestion (AD) plant for management of biodegradable portion of municipal solid waste. An experimental design and preliminary tests using co-digestion of municipal solid waste was conducted with the operation and process parameters utilized in this research work. Conceptual design was generated based on results of experimental design. The developed AD plant was evaluated for performance and the results obtained compared to an existing single stage fixed dome AD pilot plant using 100 kg of substrates with an organic loading rate of 3 kg/m3day for an operating time of 163 days. The cumulative biogas yield, and behaviour of the operation and process parameters utilized in this research work were evaluated. The results obtained reveal that unlike the single stage fixed dome AD pilot plant, the three-stage AD plant enables continuous production of biogas. Besides, optimum conditions of neutral pH range of 6.99 m to 7.01 m, slurry mesophilic temperature range of 37.05 °C to 37.15 °C, and organic loading rate of 3kg/m3d that favoured optimum biogas yield were established.