William Kisaalita, a tissue engineer from the University of Georgia, USA, and his team have developed a milk cooler that can run on bio-gas, i.e. fermented cow dung. The device can cool 20 litres and was designed to help dairy farmers in Urganda, some of whom throw their milk away at the end of the day as they have no way to prevent it turning bad. Apparently the Urgandan farmers were not so sure about the biogas aspect of the device, so it has been tweaked to run on propane which is easily available. Kisaalita hopes he will be able to convince them to try biogas in the future.