Plugging into the power of sewage.
The waste you flush down the toilet could one day power the lights in your home. So say researchers at Pennsylvania State University who last week revealed they have developed an electricity generator fuelled by sewage.
Even better, the device breaks down the harmful organic matter as it generates the electricity, so it does the job of a sewage-treatment plant at the same time. Penn State's microbial fuel cell (MFC) harnesses chemical techniques similar to those the body uses to break down food - but diverts the electrons liberated in the reactions to produce electrical energy.
"There are extraordinary benefits if this technology can be made to work," comments Bruce Rittmann, an environmental engineer at Northwestern University in Illinois.
Many developing countries urgently need sewage processing plants, for example, but they are prohibitively expensive, largely because they use so much power. Offsetting this cost by producing electricity at the same time could make all the difference, says Bruce Logan, who led the development team at Penn State.
Sewage contains a slurry of bacteria and undigested food, consisting of organic matter such as carbohydrates, proteins and lipids. The bacteria found in sewage treatment works use enzymes to oxidise organic matter, in a process that releases electrons.
Normally the electrons power respiratory reactions in the bacterial cells, and are eventually combined with oxygen molecules. However, by depriving the bacteria of oxygen on one side of the MFC, the electrons can be wrested from them and used to power a circuit.
Source: New Scientist
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