In a 15-month feasibility study funded by the Engineering and Physical Sciences Research Council (EPSRC) to the tune of 24 pounds (around 000 euros), researchers from the School of Biosciences at the University of Birmingham showed that 'A specific bacterium produces hydrogen when it feeds on highly sweet waste. The tests were carried out with waste from the international confectionery and beverage company Cadbury Schweppes, which is based in Birmingham. Another partner, C-Tech Innovation, is studying the economics of the process and has shown that this technology could be of interest on a larger scale.
When tested in a demonstration reactor of 5 liters, these bacteria were added to a mixture of diluted nougat and caramel waste.
The bacteria then consumed the sugar, producing hydrogen and organic acids. Another type of bacteria is introduced into a second reactor in order in turn to convert the organic acids into hydrogen. The hydrogen then feeds a fuel cell to produce electricity (chemical reaction between hydrogen and oxygen in the air). The carbon dioxide formed in the first reactor is captured and sequestered so as not to be released into the atmosphere.
The resulting biomass waste is removed, mixed with palladium, and then used as catalysts in another research project. This second project is funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and aims to identify different mechanisms for removing pollutants such as chromium and polychlorinated biphenyls (PCBs). The catalytic reactors used in this parallel project also require hydrogen, which is therefore that supplied by the waste from confectionery.
This process is therefore clean, saves energy and allows the confectionery industries to recover their waste rather than depositing it in landfills as they currently do. This process could theoretically be used by most food companies.
However, tests carried out with potato extracts have not been conclusive.
Professor Lynne Macaskie of the University of Birmingham believes the system could be developed for industrial power generation and waste treatment processes. The research team is currently engaged in follow-up work in order to obtain more information on the overall potential of this technique with more varied “sweet” waste.