In Copenhagen – the capital city of Denmark – one of the trendiest spots is the public outdoor swimming facility in the Islands Brygge area where Copenhageners come to relax during the summer.
Yet only 15 years ago this would have been impossible because the water was polluted to the extent that it posed a health risk. As a result of a long-term effort by Copenhagen municipality, you can swim in the water in the centre of Copenhagen.
For many years, the discharge of waste water from sewers and industrial companies polluted the water in Copenhagen harbour, and outdoor swimming became a thing of the past. The water was heavily polluted with sewage, algae, oil spills and industrial waste.
Today, the situation is vastly improved as a result of Copenhagen Municipality’s efforts to improve the recreational environment in the harbour area. Copenhageners can now enjoy swimming in clean water thanks to the Municipality’s investments in expanding its wastewater treatment plants to remove nutrient salts and minimise discharge of heavy metals, as well as in modernising its sewer system.
Managing heavy rainfall
The progressive improvement of water quality in the harbour in recent years can especially be attributed to a reduction in the discharge of waste water during rainfall.
In 1995, 93 overflow channels fed waste water into Copenhagen harbour and the adjacent coastlines. Since then, the municipality has built rainwater reservoirs and reservoir conduits, which can store waste water until there is space again in the sewage system.
This has resulted in the closing of 55 overflow channels so that today, it is only during very heavy rainfall that waste water containing bacteria and other pollutants is discharged to the harbour. On these isolated occasions, of which there are very few during the summer season, an established on-line warning system calculates the water quality in the harbour and the swimming facility at Islands Brygge is closed if the water quality is poor.