Biomass waste‑to‑energy valorisation technologies: a review case for banana processing in Uganda

TitleBiomass waste‑to‑energy valorisation technologies: a review case for banana processing in Uganda
Publication TypeJournal Article
Year of Publication2017
AuthorsGumisiriza1, R, Hawumba, JFuna, Okure, M, Hensel, O
JournalBiotechnology for Biofuels
KeywordsAnaerobic digestion, Banana waste, Bioenergy, Biofuels, Biomass energy, Biomass valorisation, Waste-to-energy technologies

Uganda’s banana industry is heavily impeded by the lack of cheap, reliable and sustainable energy
mainly needed for processing of banana fruit into pulp and subsequent drying into chips before milling into banana
flour that has several uses in the bakery industry, among others. Uganda has one of the lowest electricity access levels,
estimated at only 2–3% in rural areas where most of the banana growing is located. In addition, most banana farmers
have limited financial capacity to access modern solar energy technologies that can generate sufficient energy for
industrial processing. Besides energy scarcity and unreliability, banana production, marketing and industrial processing
generate large quantities of organic wastes that are disposed of majorly by unregulated dumping in places such
as swamps, thereby forming huge putrefying biomass that emit green house gases (methane and carbon dioxide).
On the other hand, the energy content of banana waste, if harnessed through appropriate waste-to-energy technologies,
would not only solve the energy requirement for processing of banana pulp, but would also offer an additional
benefit of avoiding fossil fuels through the use of renewable energy.
Main body: The potential waste-to-energy technologies that can be used in valorisation of banana waste can be
grouped into three: Thermal (Direct combustion and Incineration), Thermo-chemical (Torrefaction, Plasma treatment,
Gasification and Pyrolysis) and Biochemical (Composting, Ethanol fermentation and Anaerobic Digestion). However,
due to high moisture content of banana waste, direct application of either thermal or thermo-chemical waste-toenergy
technologies is challenging. Although, supercritical water gasification does not require drying of feedstock
beforehand and can be a promising thermo-chemical technology for gasification of wet biomass such as banana
waste, it is an expensive technology that may not be adopted by banana farmers in Uganda. Biochemical conversion
technologies are reported to be more eco-friendly and appropriate for waste biomass with high moisture content
such as banana waste.
Conclusion: Uganda’s banana industrialisation is rural based with limited technical knowledge and economic capability
to setup modern solar technologies and thermo-conversions for drying banana fruit pulp. This review explored
the advantages of various waste-to-energy technologies as well as their shortfalls. Anaerobic digestion stands out as
the most feasible and appropriate waste-to-energy technology for solving the energy scarcity and waste burden in
banana industry. Finally, potential options for the enhancement of anaerobic digestion of banana waste were also