Turning Rotten Food into Fuel
A Stuttgart-based plant that converts food waste into biogas. Photo: Fraunhofer IGB.
In an increasingly resource-conscious society, the familiar environmental adage “waste equals food” usually implies recycling discarded material to make new products. However, trash also has value in the generation of energy. Researchers at Germany’s Fraunhofer Institute have recently developed an efficient way to convert discarded vegetables and fruits into natural gas. The procedure utilizes the organic waste’s natural fermentation process to generate and capture biogas, which is stored in compressed cylinders to be used as fuel.
“The waste contains a lot of water and has a very low lignocellulose content, so it’s highly suitable for rapid fermentation,” says Ursula Schließmann, head of the IGB department at the Fraunhofer Institute for Interfacial Engineering and Biotechnology. “We hold the waste in several storage tanks, where a number of parameters are automatically calculated – including the pH value. The specially designed management system determines exactly how many liters of waste from which containers should be mixed together and fed to the microorganisms.”
The conversion process requires only a few days, and the fuel is being developed for use in methane-powered vehicles. Given the unfortunately large amount of global food waste, the new method—which seeks to make use of organic trash from large markets and cafeterias—could be used to increase food resource efficiency.