A confectionery waste bioenergy study by Dr Carol Ngwenya shows how sugary food waste can be turned into renewable energy instead of going to landfill.
Dr Carol Ngwenya recently completed her PhD in Chemical Engineering. Her research explores how carbohydrate-rich confectionery waste can produce bioenergy.
She evaluated the feasibility of producing bioethanol, biobutanol and biogas using different microbial systems. The results show that these waste streams can be converted into energy, especially when processes are optimised and microbes adapt to the material.
Waste as a resource
Titled “The feasibility of renewable bioenergy production from carbohydrate-rich waste streams: confectionery waste as a case study”, the study responds to growing calls for a sustainable bio-based economy in South Africa.
“Carbohydrate-rich waste streams generated by food processing industries are often discarded despite their high energy potential,” said Ngwenya.
She said the research was driven by the need to redirect such waste into biological processes for renewable energy production.
The study aligns with national strategies such as the Waste Research, Development and Innovation (RDI) Roadmap and the Integrated Resource Plan. Both promote the use of waste as a renewable resource.
According to the United Nations Environment Programme, food waste contributes significantly to global greenhouse gas emissions.
Comparing bioenergy pathways
A key part of the research compares different bioenergy conversion routes using the same waste material.
Ngwenya analysed bioethanol, biobutanol and biogas production to assess how different microbial systems perform. She found that performance depends on the composition of the waste stream.
The approach offers guidance for industries and innovators when selecting suitable waste-to-energy technologies. It can improve efficiency and resource use.
Opportunities for industry
The findings highlight opportunities for entrepreneurs in the waste-to-energy sector to develop practical and scalable solutions.
Converting confectionery waste into bioenergy could reduce pollution, improve waste management and support renewable energy generation.
In South Africa, such technologies may also help diversify energy supply while supporting a shift to a more resource-efficient economy.
This aligns with broader local efforts to improve waste management.
Ngwenya graduated from University of Cape Town’s Faculty of Engineering & the Built Environment on Monday 30 March.
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