High-sugar industrial waste could provide clean energy and remove pollutants from the environment. Scientists from the University of Birmingham have successfully powered a fuel cell with hydrogen generated by adding bacteria to break down confectionery waste. They then used the resulting biomass as a catalyst for cleaning industrial waste polluted with heavy metals and toxic organic chemicals.
The team is interested in forming a consortium with investors and SMEs to apply for a EU-funded project under Framework 7 to develop further energy-generating applications for high-sugar wastes.
The bacteria, a modified form of E. coli, were fed on diluted caramel and nougat waste supplied by local chocolate manufacturer Cadbury Schweppes, a partner in the research. The bacteria consumed the sugar, producing hydrogen and organic acids.
A second type of bacterium, Rhodobacter sphaeroides, was then added to digest the organic acids, generating more hydrogen. The resulting hydrogen was fed to a fuel cell to generate electricity, while the carbon dioxide produced in the process was disposed of safely.
The waste biomass from the process was then coated with palladium sourced from scrap metal and used as a catalyst to remove chromium and polychlorinated biphenyls from industrial waste. The reactors used in this process were powered by hydrogen from the confectionery waste, further underlining the green credentials of the technique.
Further research will be carried out to maximise the amount of energy generated by the process, and to streamline the reactor. According to Lynne Macaskie, who led the research team, rough calculations suggest that an improved reactor, one-tenth the size of that used in the research, could produce enough background energy for an average house.
Another industrial partner in the initiative, C-Tech Innovation Ltd, calculates that it could be viable to apply the process to industrial electricity generation and waste treatment processes. In theory, this could give the confectionery industry (and potentially other foodstuff manufacturers) the means to power factories from their own industrial waste, saving on landfill disposal costs, and even selling surplus energy.
The projects were funded by the UK's Engineering and Physical Sciences Research Council and the Biotechnology and Biological Sciences Research Council (BBSRC). Follow-up work is planned to get a clearer picture of the overall potential of the techniques.
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