From Food Waste To Hydrogen And Methane: SolidsCore Completed

The SolidScore research project is coming to an end at our university. The project focuses on dark fermentation, a process in which a reactor ferments solids—such as milk powder from the food industry—to produce hydrogen and methane.

Producing hydrogen and biomethane from food industry waste—that is the idea behind the SolidScore research project, which is now coming to a close at our university’s Department of Energy · Building Services· Environmental Engineering. These energy sources are produced through anaerobic fermentation in a newly designed pilot plant. In the reactor, bacteria ferment sugar- and starch-rich solids in the absence of oxygen and light. In the process, the plant produces biogenic hydrogen in particular. According to the research team’s reasoning, companies in the food industry could use such a plant to convert their own waste materials and utilize the hydrogen and methane themselves.

About 60 different types of waste materials were tested
“We tested about 60 different types of waste materials to see if they were suitable for dark fermentation,” says project engineer Martin Woestmann, who supervised SolidScore as part of the research team led by Prof. Dr. Elmar Brügging and Prof. Dr. Christof Wetter, together with Juliana Rolf and Sören Kamphus. “Sugar-containing products from the food industry, such as milk powder, are particularly efficient.” The hydrogen-producing bacteria are capable of efficiently metabolizing substances rich in sugar and starch. “We’re taking advantage of that.”

The substrate ferments in the reactor’s six sections—known as compartments—with two of them producing hydrogen and four others producing methane. Organic acids are also produced as byproducts. “We were able to extract approximately nine liters of hydrogen and 80 liters of methane per day from the milk powder,” says Woestmann. “This demonstrates that the dark fermentation process can be applied to organic solids.”

Focusing on Ecology and Economic Efficiency
In the previous HyTech project, the team fermented sugar-containing industrial wastewater to produce hydrogen and methane. The solids complement the process. “In future projects, the focus could be on integrating the dark fermentation process into holistic plant designs to ensure cost-effective implementation,” Woestmann muses. “After all, our goal is to put this research into practice.”

While our university researched the process, EMCEL GmbH examined its actual environmental footprint. The second project partner, PlanET Biogastechnik GmbH, assessed its economic viability. SolidScore was funded by the Federal Ministry for Economic Affairs and Climate Action based on a resolution by the German Bundestag.