Suitability of municipal solid waste in African cities for thermochemical waste-to-energy conversion: The case of Harare Metropolitan City, Zimbabwe.

The recovery of energy from municipal solid waste (MSW) has gained popularity in many industrialized countries, but its adoption in economically developing countries, especially in Africa, has been slow. While capital investments and technical requirements for waste-to-energy (WtE) systems are among the most important causes for this slow adoption, the unavailability of data on the thermochemical quality of MSW as a potential feedstock for energy recovery is also a limiting factor. In this paper, Harare, a typical African city, was selected as a case study. The evaluation was based on the analysis of the MSW's composition, moisture as-discarded, thermochemical properties and energy content. The results show that the quality of the MSW is comparable to that in regions outside Africa where WtE has been a success. The combustible fraction exceeded 75 wt% making it ideal for thermal treatment without requiring supplementary fuel. With an MSW throughput of 421,757 tonnes year (11.1% of which is recycled), and a lower heating value of 10.1 MJ kg, the energetic potential was estimated at 3.8 × 10 GJ. MSW thermal treatment via conventional technologies can reduce the waste throughput to landfills by up to 40%, provide up to 112 GWh year of electrical energy, and increase the annual share of electrical energy produced from bio-fuels and wastes from 1.3% to at least 2.2%. These benefits make thermal MSW treatment a suitable option for waste disposal in African cities.