Summary

In the washing of soils contaminated with per- and polyfluoroalkyl substances ( PFAS), current technologies are not always capable of removing PFAS from the fine fraction across all soil types, resulting in the need for landfill disposal. Within the BoReF project, PFAS adhering to the fine fraction of difficult-to-wash soils will be removed using wet mechanical methods (e.g., sword washing, attrition) and wet chemical processes (e.g., flotation, chemical oxidation) to enable the recycling of the fine fraction. The research project focuses primarily on process engineering upscaling, aiming to successfully transfer the developed solutions from laboratory and pilot scale to project scale.
Launched in April 2025, the project is supported by the Bavarian Research Foundation with funding of €430,000. In its third funding round of 2024, the Foundation’s council approved a total of approximately €5.8 million in grants for ten technology projects across Bavaria.

Problem Statement

Per- and polyfluoroalkyl substances (PFAS) are extremely persistent industrial chemicals that repel water, grease, and dirt. They are found in many everyday products such as rain jackets and pizza boxes. PFAS also enter the environment through the production of textiles, printed materials, refrigerants, propellants, and firefighting foams, accumulating in soils, food, and drinking water. PFAS are considered highly problematic: they are likely carcinogenic and are virtually non-degradable in both the environment and the human body.
When PFAS are detected—for example, during soil excavation for a construction project—the contaminated soil must either be cleaned or disposed of in landfills. Despite only slowly increasing media attention, the development of effective processes to remove this group of substances from the environment is urgently needed.

Project Description

PFAS can be removed using a specialized soil washing process. In this method, the contaminated soil is excavated and cleaned in a facility resembling a giant washing machine drum, where targeted interaction with water removes contaminants. For coarse soil fractions (such as sand and gravel), this cleaning process is already effective. However, challenges remain with the so-called fine fractions—very small soil particles with diameters of less than 0.1 mm—which currently still have to be disposed of in special landfills.
Researchers from the Chair of Resource and Chemical Engineering (Prof. Dr. Daniel Vollprecht, Samuel Griza), the Institute for Environmental Medicine and Integrative Health (Prof. Dr. Claudia Traidl-Hoffmann, Dr. Jamie Afghani), the Chair of Technology Assessment (Prof. Dr.-Ing. Jan Paul Lindner), and the Application Center for Materials and Environment Research (Dr. Timo Körner, Dr.-Ing. Christian Oblinger) at the University of Augsburg are now working together with industry partner Züblin Umwelttechnik GmbH to develop a solution that enables complete cleaning of PFAS-contaminated excavated soils.

The project aims to remove PFAS adhering to fine soil particles. The approach involves the application of wet mechanical and wet chemical processes, such as chemical oxidation, flotation, or the use of washing-active additives. To verify PFAS contamination levels, a new cost-effective analytical method will be developed to characterize the large number of required samples. To identify the most effective cleaning method for fine soil particles, the researchers are reconstructing the "soil washing machine" on a laboratory scale. The process from contaminated to cleaned and reusable soil is illustrated schematically in the figure below. The new process will be accompanied by a life cycle analysis throughout the project, providing a decision-making and evaluation basis for sustainability by quantifying environmental impacts.

Project Objective

The research conducted in BoReF aims to further develop soil washing by integrating additional wet mechanical and wet chemical processes, enabling the recycling of the fine fraction even for soils that are particularly challenging to clean. This approach helps conserve the scarce resources "soil" and "landfill space" in Germany, as the cleaned soil can be reused instead of having to be disposed of in landfills.