Pilot plant produces biogas from food waste

Stuttgart, Germany – Researchers from the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) in Stuttgart have established a pilot plant that produces biogas from food waste.

Using fruit and vegetable waste generated by wholesale markets, the group are trialling a fermentation process that produces methane which can be compressed into high-pressure cylinders and 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,” said Dr Schließmann, head of department at the IGB.

The challenge is in dealing with the varying composition of the waste. On days with a higher citrus fruit content, for instance, researchers have to adjust the pH value through substrate management.

“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 litres of waste from which containers should be mixed together and fed to the microorganisms,” said Schließmann.

Other groups involved in the project, which goes by the name of ETAMAX, include energy company EnBW Energie Baden-Württemberg and Daimler AG.

The five-year project is funded with €6m from the German Federal Ministry of Education and Research (BMBF).