A team from Ghent University is testing a water purification system in the famous canals or Reien of Bruges. The installation is designed to prevent blue-green algae (cyanobacteria). These “algae” – which are actually bacteria – can cause nausea and headaches in swimmers and are the reason why the swimming zone in the canals has been closed for most of the summer.
This summer, blue-green algae caused a lot of problems in the canals of the popular tourist destination. They are the reason why the designated swimming zone in the canals has been closed for weeks and why the open-air swimming championship organised by the Bruges IJsberen or Ice bears had to be cancelled. Even the swans of Bruges are not safe from the blue-green algae and are being kept away from areas where concentrations are too high.
In the hope of avoiding similar problems next year, the City of Bruges and Ghent University are now testing a water purification system. ‘The system consists of a closed tank in the Reien (or canals) in which we isolate a quantity of water,’ explains Prof Peter Goethals. ‘The water is then pumped to the plant where it is filtered several times. The water also passes through filters containing activated carbon, a substance to which harmful substances bind.’
The plant can purify tens of thousands of litres of water per hour.
Aquatic plants also used to combat blue-green algae
For the time being, the installation is located in the Coupure waterway, but it will soon be moved to another famous Bruges canal, the Augustijnenrei. A system with aquatic plants is also being installed there. ‘These plants can do a lot to prevent blue-green algae,’ says Goethals. "After all, they take away the nutrients and light that the algae need. However, we must also be careful when using this technique. The aquatic plants must not be allowed to proliferate and obstruct the flow of water, nor should they be allowed to attract too many water birds."
The tests should reveal whether the water purification system can be used in the Reien, whether it is practical and financially viable. As a pilot project, it is currently largely EU-funded.