The PFAStrea project aims to develop a modular concept that allows for adaptation depending on the degree of contamination and the properties of the water to be treated.
Short-chain perfluoroalkyl substances (PFAS), including perfluoroalkyl acids (PFCA) in particular, are highly water-soluble, highly mobile, and are hardly retained in the soil. As a result, they are increasingly detected in groundwater and surface water, and even in human blood. Conventional methods used, for example for groundwater remediation, such as activated carbon filtration, cannot efficiently remove short-chain PFAS. Furthermore, PFAS are not destroyed by such processes (or others, e.g. foam fractionation), but concentrated. Despite research efforts, there is currently no practical and economical method for removing short-chain PFAS such as perfluorobutane (PFBA, C4 chain length). Against the backdrop of the new Drinking Water Ordinance (July 2023), water suppliers are obliged to adapt to the new limit values by January 2026 and 2028 and to upgrade or convert their drinking water treatment systems accordingly, depending on the raw water contamination. In addition, those responsible for contaminated sites are under increasing pressure to remove PFAS from the environment permanently and efficiently.
The aim of this project is therefore to develop a modular concept that can be adapted to specific requirements depending on the degree of contamination and the properties of the water to be treated. This involves an initial stage in which activated carbon is specifically modified to increase its adsorption capacity for short-chain PFAS. Electrical polarization is used to further enhance this effect. The second stage is the electrochemical treatment of PFAS-contaminated water, including desorbates from the activated carbon. Electrochemical processes are promising for the complete removal of PFAS but can also lead to the formation of undesirable by-products such as perchlorate, chlorate, and bromate. The concept therefore includes a third stage to break down these by-products microbiologically.
