Isotopic tracing and process-based modeling to identify pathways of toxic substances in stormwater biofilters (2025-2029)

Urban stormwater contains many harmful substances, such as heavy metals and organic pollutants like PFAS, alkylphenols, phthalates and bisphenol A. Although levels are often low, the large volumes of untreated stormwater discharged to lakes and rivers lead to significant negative environmental impacts.

To reduce this, stormwater biofilters are used to treat stormwater close to its source. Despite their widespread use, there is still a lack of understanding of the biological and chemical processes taking place in biofilters. They are often considered as 'black boxes' where only the overall treatment effect is measured, without insight into what actually happens inside the system.

This project aims to create a deeper understanding of the various processes pollutants can undergo in stormwater biofilters, including sorption, physical filtration, accumulation in plants, volatilization and biodegradation. By identifying and analyzing the specific mechanisms behind the treatment, the goal is to enable more efficient design and control of these systems. In the long run, this will help to reduce the load of hazardous substances in our waterways and increase the chance of achieving both national environmental goals and global sustainability goals.

Building on ongoing research, this project aims to provide a comprehensive understanding of the processes governing the retention and fate of toxic substances by developing process-based computational models using field data and novel laboratory experiments using isotope tracing (C14). Results from this project will provide valuable data for improving biofilter design and thus performance.

The project is funded by Formas.