Browsing by Author "Isabirye, Ibrahim"

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    Investigating the energy potential of selected municipal solid waste in Mbale city.
    (Busitema University, 2026) Isabirye, Ibrahim
    Solid waste management poses significant environmental and energy challenges for rapidly urbanising cities such as Mbale, Uganda. This study investigated the energy potential of three selected municipal solid waste fractions banana leaves, disposable diapers, and polythene bags in Mbale City, to identify their suitability for waste-to-energy (WtE) conversion pathways. Bomb-calorimetry-based proximate analysis showed net calorific values of 13.86 MJ/kg (equivalent to 3,851 kWh per tonne) for banana leaves, 18.50 MJ/kg (5,138 kWh per tonne) for disposable diapers, and 46.03 MJ/kg (12,785 kWh per tonne) for polythene bags, identifying polythene bags as the highest-value feedstock for thermochemical conversion. Laboratorybased biochemical methane potential (BMP) tests were conducted on boiled, alkali-pretreated banana leaves co-digested with cow dung at seven mixing ratios to evaluate biogas yield, methane content, and energy recovery. Physicochemical characterisation showed that banana leaves possess a high carbon-to-nitrogen (C:N) ratio that, when balanced through co-digestion with cow dung, improved methane yield. A 1:2 banana-leaf-to-cow-dung ratio produced the highest methane volume (330 mL from a 1,200 g digester charge, equivalent to a biochemical methane potential of 1.59 mL CH₄/g volatile solids), yielding a laboratory-scale energy recovery potential of 11.81 kJ — equivalent to approximately 12.2 kWh of recoverable methane energy, or 3.65 kWh of deliverable electricity at a 30% generator efficiency, per tonne of banana-leaf waste treated under the boiled and alkali-pretreated conditions used in this study. A multi-criteria Analytic Hierarchy Process (AHP) assessment further indicated that gasification is the most suitable technology for polythene bags, incineration for disposable diapers, and anaerobic digestion for banana leaves. Collectively, the three waste streams account for over 62% of Mbale City's municipal solid waste by mass, and a hybrid WtE strategy combining these technologies is estimated to yield a combined practical generation potential of approximately 4.17 MW for the city, overwhelmingly dominated by the thermochemical conversion of polythene bags and diapers. This research provides evidence-based guidance for sustainable municipal solid waste management and waste-to-energy technology selection in secondary Ugandan cities.