Zeolite in infiltration swales to improve pollutant retention

Infiltration swales are popular infrastructure elements in cities. Not only do they have the ability to store and infiltrate rainwater, but they also purify it. Additionally, they provide an opportunity to increase biodiversity through their plantings. However, continuous exposure of the swales to pollutants poses a risk that these pollutants accumulate, and after a long period of time, they may break through the 20-30 cm topsoil layer of the swales, which could result in soil and groundwater contamination.
 

To improve the retention of copper from stormwater runoff from copper roofs, zeolite is being tested as an additive in the topsoil zone. For this purpose, 18 infiltration basins were constructed on a semi-technical scale in various configurations. These swales feature different soil compositions, both with and without zeolite, and are complemented by various plantings. Additionally, the effectiveness of a pure zeolite layer on the vegetated soil zone is being investigated. Such a layer could be more easily replaced, regenerated, and reused after becoming saturated with copper. The semi-technical trials are being subjected to stormwater runoff from a nearby copper roof for a period of at least one year to capture seasonal variations.