Sustainable Cities™

Copenhagen: From sewer to harbour bath

In Copenhagen, Denmark, many years of investments in the sewage system has revitalised the harbour. The revitalisation is mainly due to a remarkable reduction in the discharge of wastewater during rainfall. This case focuses on how municipal strategies and investments towards cleaning up the harbour have resulted in a water quality so high that people can now swim in the harbour. In 2002, a public harbour bath opened in the area of Islands Brygge. Today, the harbour bath is a striking urban oasis that marks Copenhagen´s position as a clean and liveable city.

Københavns Havnebad ved Islands Brygge, foto Esben Bruun, venligst udlånt af PLOT

For many years, the discharge of wastewater from sewers and industrial companies had a major impact on the water quality in Copenhagen harbour. The water was heavily polluted with sewage, algae, industrial waste and oil spills from commercial harbour transport.

In 1995, 93 overflow channels fed wastewater into Copenhagen harbour and the adjacent coastlines. Since then, the municipality has built rainwater reservoirs and reservoir conduits, which can store wastewater until there is space again in the sewage system. This has resulted in the closing of 55 overflow channels. Today, wastewater is only discharged to the harbour during very heavy rainfall.

Municipal investments in a modernisation of the sewage system and an expansion of the city´s wastewater treatment plants, which are to remove nutrient salts and minimise discharge of heavy metals, has revitalised the harbour of Copenhagen. In 2002, the first public harbour bath opened in the area of Islands Brygge, making Copenhageners among the few people in Europe able to bathe in their harbour without jeopardising their health. An established on-line warning system calculates and monitors the water quality in the harbour. If the water quality is poor, the swimming facilities are immediately closed. 


Today, Copenhagen harbour is almost as clean as the water in the Sound. The high water quality and the popular recreational bathing facilities along the harbour front are some of the elements in the city's vision to become the capital city in the world with the best urban environment by 2015.

"It is crucial for people worldwide to understand that water, as well as waste water, is a valuable resource that needs to be handled imaginatively and frugally. 'Waterproofing' our cities require the involvement not just of specialists, but of everyone." Herbert Girardet "CitiesPeoplePlanet" (2008)

Last updated Friday, September 25, 2015