Nature based solutions to reduce microplastics in the stormwater – pilot station in Gdansk is ready
After six months of intensive work and strict cooperation with Gdansk University of Technology, Gdansk Water Ltd launched the pilot station for the stormwater treatment in August 2020.
The installation was established to verify the effectiveness of microplastics reduction from the stormwater, using Nature Based Solutions (NBS) – properly selected filtration beds and plants (hydrophytes). It is located close to the place, where the stormwater from the city of Gdansk is directed to the Baltic Sea.
And how does it work?
The stormwater from the stormwater collector is directed to a system of 5 steel tanks. The first tank contains probes that are used to measure basic parameters of water flowing into the station (e.g. pH, temperature, oxidation-reduction potential (redox), conductivity, turbidity, and dissolved oxygen content). It also plays the role of a sedimentation tank, in which the sedimentation process, i.e. falling of suspensions, occurs. Two more tanks are filled with a filter bed (sand and gravel of suitably selected grain size), in which the common reed (Phragmites australis) has been planted. Tank No. 2 is a bed with vertical flow (VF-CW), and Tank No. 3 – with horizontal flow (HF-CW). After passing through the subsequent filter beds, the water goes to tank No. 4, which acts as a cleaning pond with a variable depth filter bed. The last, fifth tank stores purified water and, like tank No. 1, is equipped with a measuring system.
In October we collected first samples from the pilot installation using the special sampling device – Universal Filtering Object (called UFO).
Analysis of the content of microplastics in water collected before and after the purification process will be carried out by scientists from the University of Aalborg (Denmark). We hope that the rults will confirm the effectveness of NBS systems to remove microplastics from the stormwater and therefore will be popularized as the recommended technology to treat the stormwater in the cities.