In a 15 month feasibility study funded by the Engineering and Physical Sciences Research Council (EPSRC) up to 24 000 pounds (about 35 000 euros), researchers from the School of Biosciences at the University of Birmingham have shown that a specific bacterium produces hydrogen when it feeds on highly sugary waste. The tests were conducted 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 sugar, producing hydrogen and organic acids. Another type of bacteria is introduced into a second reactor in order to convert the organic acids into hydrogen. Hydrogen then feeds a fuel cell to produce electricity (a 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 biomass waste resulting from the process 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 provided by the confectionery waste.
This process is therefore clean, saves energy and allows confectionery industries to recycle their waste rather than deposit it in landfills as they currently do. This process could theoretically be used by most agribusiness companies.
Nevertheless, tests with potato extracts were inconclusive.
Professor Lynne Macaskie of the University of Birmingham believes the system could be developed for industrial electricity production and waste treatment processes. The research team is currently engaged in a follow-up work to obtain more information on the overall potential of this technique with "sweet" waste more varied.