Electricity generation from biogas as resource recovery potential from solid waste composition in a mixed-income municipality

Abstract

Knowledge gaps on municipal solid waste composition for energy potential render most developing countries unprepared for waste-to-energy technology treatment. Sub-Saharan African countries, such as Ghana, commonly use skip containers for waste collection and dispose of in landfills. To assess the global warming potential under anaerobic digestion, estimate biomethane conversion to electricity and evaluate some economic viability for a decentralized biogas plant, 10 skip containers from trucks were sampled from Oforikrom Municipality. The skips were selected from a mixed-income municipality, where households, markets, and wood industry areas share common skip containers for weeks before disposal. Such data are scarcely reported in the literature. The waste generation rates from skip containers were quantified, and their physical and chemical compositions were measured according to standards. The physical composition showed that organic, recyclables and non-recyclables consist of 40%, 34% and 26% respectively, with 52% of the waste fractions> 100 mm. It was found that skip location affects composition. It was revealed that the standard deviation for fractions of unprocessed municipal solid waste in each skip container decreased in the order of households> market> wood activity. The methane yield for anaerobic digestion was estimated to be about 224021.24 $m^3/\mathrm{yr}$. The electricity generation potential was found to be 601870.65 $\mathrm{kWh}/\mathrm{yr}$. The Net Present Value of 5.11 million US dollars showed that the anaerobic digestion project was financially viable. The payback period determined was found to be approximately 2 years. The amount of ${\mathrm{CO}}_2\mathrm{eq}$ of the GHG that would be displaced if biogas is utilised for electricity generation is 200.78 ktons in a year. Therefore, the nationally determined contribution emission reduction target for Ghana from 2020 to 2030 (21,313.0 kt${\mathrm{CO}}_2\mathrm{eq}$) by adopting alternative urban solid waste management can be reduced by 7.54% when operating this biogas plant from 2023 to 2030.