Copenhagen: From sewer to harbour bath

Copenhagen has revitalised its harbour. The revitalisation is mainly due to a remarkable reduction in the discharge of wastewater during rainfall.

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.

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.

Copenhagen harbour bath at Islands Brygge, by Casper Dalhoff, courtesy of PLOT

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)

København: Fra kloak til havnebad

I København har mange års investeringer i kloaksystemet revitaliseret havnen. Den forbedrede vandkvalitet tilskrives især den meget reducerede belastning med kloakoverløb under regnvejr. Denne case fokuserer på, hvordan kommunale strategier og investeringer i en rensning af havnen har resulteret i en så høj vandkvalitet, at det nu er muligt at bade i havnen. I 2002 åbnede det offentlige havnebad på Islands Brygge. I dag er det en af byens iøjnefaldende oaser, som er med til at cementere Københavns position som en ren og bæredygtig storby.

Vandkvaliteten i Københavns havn har gennem tiden været stærkt påvirket af spildevandsudledninger fra husholdninger og industrielle virksomheder. Kloakudløb, alger, industriaffald og oliespild fra kommerciel skibsfragt har været nogle af de væsentligste årsager til forureningen.

I 1995 var der 93 overløbskanaler, der førte spildevand ud i Københavns havn og de tilstødende kystområder. Siden da har Københavns Kommune bygget regnvandsreservoirer og lagt ekstra vandledninger, der er i stand til at opsamle afløbsvand, indtil der igen er plads i kloaksystemet. Dette har resulteret i lukningen af 55 overløbskanaler. I dag bliver spildevand indeholdende kolibakterier og andre forurenede elementer kun ledt ud i havnen ved meget kraftig nedbør.

Københavns havnebad på Islands Brygge, foto af Casper Dalhoff, venligst udlånt af PLOT

Mange års kommunale investeringer i en modernisering af afløbssystemet og en udvidelse og modernisering af byens spildevandsanlæg, så næringsstoffer og tungmetaller fjernes fra det udledte vand, har resulteret i en revitalisering af Københavns havn. I 2002 åbnede det første offentlige havnebad på Islands Brygge. Som nogle af de eneste storbybeboere i Europa kan københavnere i dag bade i deres havn uden sundhedsmæssig risiko. Et etableret online advarselssystem beregner og monitorerer dagligt vandkvaliteten i havnen. Er der kolibakterier i vandet, lukker Center for Park og Natur, der står for overvågningen, straks byens havnebade.

Vandkvaliteten i Københavns havn er i dag næsten lige så fin som i Øresund. Den fine vandkvalitet og de populære havnebade langs havnefronten er nogle af de elementer, der indgår i byens vision om at blive hovedstaden med det bedste storbymiljø i verden i 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)

Copenhagen harbour bath by Esben Bruun, courtesy of PLOT

• Investments in the sewage system and wastewater treatment plants can improve a harbour city´s water quality to an extent where it becomes clean enough for swimming
• The harbour bath at Islands Brygge is one of the most popular spots in Copenhagen in the summer – both for residents and tourists
• Copenhagen’s clean harbour is an important element in branding the city as one of the most sustainable capitals in the world

Municipal investments in the modernisation of the sewage system, including building rainwater reservoirs and reservoir conduits which can store waste water until there is space again in the sewage system.
Municipal investments in an expansion of the waste water treatment plants serving the city to remove nutrient salts and minimise discharge of heavy metals. A regional waste water treatment centre was established in cooperation with 7 neighbouring municipalities.
Creation of an online municipal warning system that calculates and provides information about the water quality in the harbour.
Strategic efforts to create urban recreational facilities such as public harbour baths. “A green and blue capital city” is one of four main goals guiding Copenhagen towards becoming the eco-metropole of the world by 2015

Inhabitants: 595.933 (1 Jan 2007)
Size: 97 sq. km.
Density: 6143 sq. km
GDP – per capita (PPP): USD 35,787 (2007 est.)
No. 11 on World Bank List, wikipedia 27 Nov. 2008
Capital of Denmark
Continent: Europe

In 1976, the City of Copenhagen formulates its first Waste Water Management Plan.

Copenhagen establishes wastewater treatment plant Lynetten in 1980. In 1997, a modernised version opens with improved facilities to handle wastewater, sludge and incineration.

Over the years, the quality of water in Copenhagen harbour improves significantly. This improvement derives primarily from the considerably reduced amount of wastewater entering the harbour from sewer overflows during heavy rain.

Sewage system overflows impact negatively on the environment in several ways. Therefore, extremely high priority is given to reducing their occurrence. The key contaminants are:

nutritive salts (over-fertilize the water and cause algae growths)
bacteria (destroy the sanitary-hygienic state of the harbour water)
heavy metals and environmentally injurious substances (are poisonous)
organic substances (diminish oxygen levels around the discharge sites and increase the need for harbour clean-up)

Case: Swimming in Copenhagen harbour [1]

Islands Brygge Harbour Bath [2]

Denmark [3]’s largest wastewater treatment centre, Lynetten [3] (only in Danish)

Eco-metropole: Vision for Copenhagen 2015 [4]

Copenhagen elected as the world´s most livable city by Monocle [5]

A history of water quality in Copenhagen harbour [6]

“In 2015 Copenhagen will be justifiably famous as the capital city in the world with the best urban environment. It will have become the eco-metropole of the world, thus demonstrating that environmental concern adds an extra dynamic to urban development.”

For further information, please read more about the Copenhagen vision [7].

The City of Copenhagen [8]

Københavns Kommune [9] (in Danish)

Guide to Copenhagen. On Islands Brygge area, please view 4 1/3 minutes into the video

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