Pilot 1: Common reed filter
Stormwater filters of harvested common reed have been tested for removal om microplastics from stormwaters and especially from meltwaters of urban snow in the FanpLESStic-sea project. The common reed filter pilot was placed in River Kymijoki that receives melt water from snow collected in the city center of Kouvola, Finland.
About 350 bundles of reed were used in the filter. The length of the bundles varied from 120 to 200 cm, the diameter of the bundles was ca. 20 cm and the weight of individual bundles 3–4 kg. The reed bundles were placed in the ditch parallel to the water flow and three logs were put on top of the reed bundles to press the filter and to keep the bundles in place.
Samples were taken and analysed from snow and from the ditch water before and after the reed filter at various times.
In conclusion, the reed filter is easy and cheap to build and maintain, and it is locally adaptable. Local conditions also influence the removal efficiency and operating time of the reed filter. The other reed filters in Kouvola have operated well for about two years before any need for changing the reed material.
Read more in the report Piloting technologies for microplastics removal from urban waters