Browsing by Author "Kabenge, Isa"

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    Banana plant wastes for biofuels: indicators from characterization for thermochemical conversion
    (Taylor & Francis, 2026-03-19) Menya, Emmanuel; Wakatuntu, Joel; Turyasingura, Medard; Okot, Christopher; Storz, Henning; Kabenge, Isa; Kizito, Simon Savio; Komakech, Allan John; Olupot, Peter Wilberforce; Okello, Collins
    The banana value chain in Uganda generates a wide range of waste biomass, yet its suitability for thermochemical conversion remains largely unstudied. This study aimed to characterise banana rhizome, pseudostem, peduncle and inflorescences from Mbwazirume and Mpologoma cultivars in Uganda for potential use in thermochemical conversion processes. These wastes were characterised for lignocellulosic, proximate, elemental, and mineral composition, and higher heating value (HHV). Moisture content ranged from 9 to 14wt%, volatile matter 74-82%db, fixed carbon 12–17%db, and ash content 3-13%db. Inflorescences exhibited the highest lignin content (15.23–17.23%daf) and HHV (14.55–15.85 MJkg−1) across cultivars, suggesting higher suitability for biochar production compared to its counterparts. However, inflorescencesexhibited the highest nitrogen content (2.47–2.56%daf), suggesting higher NOx emissions potential. Inflorescences, rhizomes and peduncle exhibited higher ash content (6–13%db) than pseudostem (3.35–3.85%db), suggesting increased risk of slagging and fouling of heat transfer surfaces. Predominant mineral elements were found to be K (15888–28363 ppm), Ca (2000–9000 ppm), Si (2000–9000 ppm), and Mg (1120–4928 ppm), which can have catalytic functions during thermal decomposition. The low fuel ratio (0.16–0.22) of the wastes suggested poor fuel properties. These properties could be enhanced through torrefaction, making the wastes more suitable as sustainable feedstocks for biofuel production.
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    Comparative analysis of energy recovery and digestate quality from anaerobic co-digestion of fruit and vegetable wastes under ambient and mesophilic conditions
    (Scientific reports, 2026-05-14) Kabenge, Isa; Komakech, Allan. J.; Rubagumya, Isaac; Kizito, Simon Savio; Ahmadisedigh, Hossein; Menya, Emmanuel; Lépine, Julien; Zziwa, Ahamada
    Large quantities of fruits and vegetables are lost along the supply chain due to their perishable nature, with factors such as inadequate refrigerated transport, poor road conditions, and limited cold storage facilities contributing to this loss. Anaerobic digestion offers a promising solution for mitigating the negative impacts of fruits and vegetable wastes (FVW). This study investigated the anaerobic co-digestion of FVW under ambient and mesophilic conditions, focusing on biogas yield, digestate quality, and energy efficiency. A 50:50 mixture of FVW and cow dung at mesophilic temperatures resulted in the highest biogas yield of 1,328.4 mLg-1VS, with a specific methane yield of 258.4 mL CH4 g-1 VS. The digestate from this mixture contained 64.56, 15.34, and 20.32 gkg-1 of nitrogen (N), phosphorus (P), and potassium (K), respectively. The heavy metal concentrations of copper (Cu), zinc (Zn), lead (Pb), iron (Fe), and manganese (Mn) were 0.02, 0.51, non-detectable, 88.60, and 3.67 mgkg-1, respectively, all falling within the acceptable limits for digestate/compost quality according to national and international standards. However, additional regulated metals such as As, Cr, Hg, Se, and Cd were not analyzed in this study. Therefore, compliance with international biofertilizer standards should be limited to the analyzed heavy metals. Although the average H2S levels remained below 22 ppm, routine monitoring is advisable, as elevated levels can compromise biogas quality, necessitating additional costs for biogas purification. From an energy recovery perspective, integrating insulation and correctly sizing the tank was found to improve both energy yield and operational efficiency, thereby enhancing the overall sustainability of the anaerobic digestion system. Further research should focus on temperature adaptability experiments in different climate zones, co-digestion with other organic wastes, long-term operational stability testing at the pilot scale, heavy metals and microbial analysis of the solid digestate.