Urban Hotspring

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Short description

A floating swimming pool heated by industrial residual heat.


A floating swimming pool heated by industrial residual heat, in the Port of Rotterdam.




Starting date:







  • Investment

    4.240.000 Euros

  • Labor

    18 FTE

  • Operation cost

    2.450.000 Euros

  • Annuals revenue

    3.000.000 Euros

  • Annual balance

    45.000 Euros

  • Pay-back time

    6 Years

Material flows

  • Inputs

  • city heating
    1250 Gj/year hot water
  • tap water
    650 m3/year (swimming) water
  • Outputs

Qualitative Analysis

Description of the Process

Warmtebedrijf Rotterdam is interested in provide a floating swimming pool in the Rijnhaven with heat. The swimming pool will be heated using the return line of the city heating. The swimming water will be filtered using a biological filtration without any chemicals, or as less possible according to dutch regulation. Two reused river barges will house the hotspring.


Last century most swimming pools in Rotterdam used to be floating in the river. Mazed fences and a wooden floor formed a basin with water of the river where people could swim. Clothing cabinets were situated around the basins. In many other European cities this was a common (and cheap) type of swimming pool. In 1962 the last floating swimming pool in Rotterdam was closed down because of industrial pollution of the water.  

Policy and legal context

Dutch regulation of swimming water will be updated in 2012 (the new 'zwemwaterwet'). It will replace the mean-based instruction by the target-based instruction. It is not clear yet if completely chlorine free swimming water for public use will be permitted, but probabely much less chlorine will be alowed. Other means of desinfecting and purifying the water can be used like natural filtration or a combination of salt electrolyse and UV.

A chlorine free swimming pool saves a lot of energy in ventilation because the damp and air above the water doesn't contain chlorine which effects eyes and respiratory tracts. 

Factors that contributed to the success of the project

There is a need for a public swimming pool, the areas of central and west Rotterdam offer less than the norm (0,0010 m2) of public swimming accommodation. The city would like to improve its image by offering a hip and trendy ‘swimming boat’.  This fits neatly in the trend of more experience based recreation. At the same time Rotterdam is trying to diminish its CO2 emissions. At the chosen site the possibility exists to use waste heat of the city heating. Sponsoring by the energy company and by the company that rents out the mooring places might be possible. An impressive view of the river and the city skyline will significantly improve the popularity of the hotspring. Added value could be had in the cross-over with neighbouring cultural destinations.

Role of different stakeholders in the system during the realization and maintenance of the project

A management team (2fte) will run the Urban Hotspring: both pool and restaurant. 

Spatial quality

The Urban Hotspring is a place where people can swim and meet in chemical-free swimming water enjoying the view of the river and the city skyline. They can enjoy this in the knowledge that the required heat was delivered by waste heat and no extra fossil fuel was burned for it.

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