Abstract:
Ghana relies heavily on fossil fuels for energy generation. This dependence on fossil fuels not only burdens the economy but also prevents the exploitation of the country’s indigenous renewable energy resources. Anaerobic digestion (AD) is one of the promising waste-to-energy technologies that has great potential for generating clean energy while solving waste management problems in Ghana. A life cycle assessment (LCA) is needed to understand the overall environmental impact of waste-to-energy technologies and to implement future alternatives sustainably. This study applied an LCA to assess the inventory results of a hybrid waste-to-energy plant in the Atwima Nwabiagya Municipality in Ghana and its impact on the environment, including greenhouse gas emissions and energy generation. The study revealed that the anaerobic digestion plant will generate 805,574 kWh/year of electricity, equivalent to 352,589 Nm3/year of biogas, from 8,615 tons of municipal solid waste. The life cycle inventory further indicated that greenhouse gas emissions, including CH4 (3,786.8 kg), NOx (1,614.48 kg), and N2O (12.79 kg), are produced, which contribute to the overall carbon footprint. Environmental benefits were observed in 10 out of 11 impact categories in the CML-IA baseline method, except for abiotic depletion, which recorded an environmental burden. Contribution analysis revealed that the transport of waste to the plant site was the highest contributor to the environmental impact of the anaerobic digestion system. Scenario analysis suggested that replacing solar PV electricity with Ghana's electricity production mix (2018) leads to a substantial reduction in the abiotic depletion category (-99.61%) but results in increased burdens, notably in acidification (725%). The uncertainty analysis showed that data reliability and temporal correlation play significant roles in quantifying uncertainty The study concluded that anaerobic digestion is a viable waste-to-energy technology in Ghana that can reduce greenhouse gas emissions and generate renewable energy, but further improvements are needed to optimize its environmental performance and reduce its resource consumption.
Description:
thesis submitted to the Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfillment of the requirements for the degree of Master of Philosophy in Chemical Engineering
