Revitalizing Blokkersdijk: returning purified water to nature

The European protected waterfowl area Blokkersdijk is facing increasing drought, as indicated by weekly water level measurements conducted by Natuurpunt Waasland for 18 years. To halt drought and mitigate biodiversity decline, Sweco, Natuurpunt and Lantis joined forces, leading to this circular idea – Eureka.

To construct the nearby Scheldt tunnel, a substantial amount of water needs to be pumped. Instead of wasting valuable water, we recover the pumped groundwater and, after thorough purification, return it to nature. The water, contaminated with PFAS, is initially treated at the Oosterweel construction site, where we designed the reference layout for the water treatment facility. Our soil colleagues continuously monitor groundwater levels through around 200 piezometers.

“We had already used half of our capacity, and yet the water level in Blokkersdijk did not rise. With this wetland project, we hope that rare plant species such as the wild orchid and bitterling will thrive once again.”

Paul Durinck, Expert Biodiversity, Sweco

In this project, we extensively studied various PFAS purification techniques in close collaboration with our partners. Subsequently, the water undergoes natural purification in the nature reserve. It passes through a sand filter and a marsh filter, both covering several hectares, before flowing into the Blokkersdijk pond through a controllable sluice.

Thanks to the initial positive results, we have already returned 50,000 m³ of water to Blokkersdijk, equivalent to about 20 Olympic-sized swimming pools.Our current goal is to return 100,000 m³ of water to the nature reserve over two years.