Waste water treatment plants as energy buffers for power grids (KEStro)

Biological processes and synergies when combining power generation and trace substance elimination

Laboratory construction of the microbial fuel cell

The growing proportion of renewable energies of the overall power supply as part of the energy revolution requires systems to balance out the supply and demand in power grids. Waste water treatment plants can contribute to this. The overall goal of the KEStro project was to develop a system to stabilise the power grid using waste water treatment plants. A microbial fuel cell powered by waste water as an energy source was combined with a novel method to eliminate micropollutants, which was used as an energy sink.

The growing proportion of renewable energies requires storage systems for the power supply to balance out the supply and demand in high-energy and/or low-energy phases. In future, waste water treatment plants can contribute to stabilising the power grid. In this joint project, a concept was therefore developed for waste water treatment plants to stabilise power grids. A microbial fuel cell operated with waste water as a renewable and continuously available energy source was combined with a novel electrochemical-biological method to remove micropollutants.

Establishing the microbial fuel cell with electrode materials not used to date was a key element of laboratory testing at TZW. In parallel to this, a novel energy-efficient process to eliminate micropollutants was optimised. To reduce the energy requirement, it was paramount to combine electrochemical decomposition and subsequent microbiological degradation of the electrochemically formed transformation products. In the second part of the project, demonstrators of a biofuel cell and a module to remove micropollutants were tested in a waste water treatment plant.

Publications

Schneider A.-L., Schell H., Hild S., Mangold K.-M., Tiehm A.: Studies into design and operation of microbial fuel cells using oxygen gas diffusion electrodes. Desalination and Water Treatment 91: 222-227 (2017)

Schneider A.-L., Tisler S., Schell H., Matthee T., Behrendt-Fryda B.., Tiehm A.: Electrochemical oxidation of iodinated X-ray contrast media by boron-doped diamond electrodes. Desalination and Water Treatment 91: 268-272 (2017)

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