Bioelectrochemical production of formic acid in biological sewage treatment plants (Wa2Chem)

Motivation/Background

In Germany, wastewater from households, storm sewers and (indirectly discharged) industry is treated in around 9,100 municipal and 2,700 industrial wastewater treatment plants (WWTP). This extensive wastewater infrastructure with its various process stages and very large material flows offers optimal conditions for the implementation of large-scale, innovative technologies within the framework of the circular economy and energy recovery. Procedures that connect different sectors (e.g. energy, production and environment) are of particular importance.

This is where the Wa2Chem project comes in. The aim of the project is the innovative coupling of anodic wastewater treatment (microbial fuel cell, MFC) and cathodic product synthesis (CO₂ reduction to formates) in a new 200 % reactor concept. Part of the energy required for the CO₂ electrolysis can be generated by bioelectrochemical wastewater treatment (MFC).

The following work steps are implemented in the project: 1. Production and operation of Sn-based gas diffusion electrodes for CO₂ reduction; 2. Modeling and simulation of the use of a 200 % cell on an ARA; 3. Combination of bioelectrochemical wastewater treatment and cathodic formate synthesis in the 200 % reactor; 4. Construction of a demonstrator and integration into ARA; 5. Testing and validation of DSP methods for adaptive separation of formic acid; 6. Balancing the material flows and an economic and ecological assessment.

In the Wa2Chem project, a formate synthesis by CO₂ reduction with a coupled MFC on a biological sewage treatment plant is used for the first time. After completion of the project, SMEs from the areas of energy and wastewater management as well as the end user market, which is characterized by SMEs, can implement the scalable reactor and integration concepts of the Wa2Chem concept.

Das IGF-Vorhaben Nr. IGF 21866 N der Forschungsvereinigung DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main wurde über die AiF im Rahmen des Programms zur Förderung der industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Klimaschutz aufgrund eines Beschlusses des Deutschen Bundestages gefördert.