Aarhus ReWater - the world’s most resource efficient wastewater treatment plant

Hovedforlag Rewater Sep2023

Meeting the needs from a growing city

In Aarhus, we need to meet the demands and expectations for a cleaner harbour and bay area creating liveability for plants, animals and people. At the same time, Aarhus Municipality is facing an annual increase in population of 5,000 people, which needs to be accommodated by increasing the capacity of the wastewater treatment plants.

The existing WWTPs in Marselisborg, Åby og Viby have proven to be too small to meet the future demands and the current locations do not allow the necessary expansion. Therefore, we need to build a new and bigger WWTP to replace them, namely the world’s most resource efficient WWTP – Aarhus ReWater. The new plant will replace Marselisborg WWTP, while the areas of the old WWTPs in Åbyhøj and Viby will be used for climate adaptation.
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Making room for urban development

The consolidation of our WWTPs serves not only a more efficient and cost-effective operation and reduction of the environmental impact – it also unleashes new possibilities for urban development.

The new wastewater treatment plant, Aarhus ReWater, will be located nearby the current Marselisborg WWTP at Tangkrogen – at the foot of the forest, and at the beginning of an attractive coastline. Our goal is to utilize the specific potential of the site and the central location to make sure that the new plant fit into the local surroundings. At the same time, our goal is for the plant to contribute positively to the development of both Tangkrogen locally and in terms of liveability in Aarhus in general by obtaining a multi-functionality in design and land use.
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A healthy water environment

The new plant will create an even healthier water environment in the bay with less nitrogen oxide and phosphorus. Nitrogen emissions will be reduced by up to 25 percent and phosphorus emissions by up to 40 percent in 2031.

This will ensure that we protect nature and wildlife - and that we can continue to swim, sail and enjoy the ocean without any health risks.

New wastewater treatment for a city in growth - protecting the water environment. Interview with COO Claus Møller Pedersen

Focus on the green transition - interview with project manager, Aarhus Rewater, Inge Halkjær

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More than wastewater

Using state-of-the-art technology to enhance its performance, the WWTP will set new standards both nationally and internationally. Our ambition is to establish not only a wastewater treatment plant but a ‘resource plant’. By this we mean that the plant, in addition to the purifying of water, will also produce energy and nutrients from the wastewater to an unprecedented extent.

Developing the new WWTP into a future resource plant, we have chosen to name the new plant Aarhus ReWater. The “Re” referring to the words “resources”, “recycle”, “reuse” and “rethink” allowing for a broader mind-set on how to manage.

Rewater Visualisering Sep 2023

A resource plant

Aarhus ReWater will not only be treating wastewater, but also produce energy from the wastewater to an unprecedented extent. Resources that today are classified as waste, can be used for green energy, heating, and fertiliser. The new plant will be utilizing these valuable resources from the wastewater to produce electricity and heat. The ambition is to have an energy neutral supply of drinking water and wastewater treatment.
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A learning plant for the future

Our ambition on making it the world’s most resource efficient WWTP cannot be achieved by today’s technologies and solutions. Therefore, the ambition is not to build a plant that stands unchanged, but a plant that will constantly help us expand our knowledge and therefore can be continually improved.

Technology and requirements are constantly changing. Therefore, our job is not to build a finished plant, but to build a “learning” plant that will be able to meet the existing demands while still being adaptable and making us wiser. Thus, Aarhus ReWater will be a place for developing and testing new and optimized treatment processes.


Inge Halkjar Jensen

Inge Halkjær Jensen

Project Manager, Aarhus ReWater

Collaboration partners

In connection with the realisation of Aarhus ReWater, Aarhus Vand will join forces with a large number of collaboration partners.

The turnkey contractor team for the wastewater resource recovery facility (WRRF)

  • Turnkey contractor: Per Aarsleff A/S.
    Subconsultants: KWR Water Research Institute and HaskoningDHV Nederland B.V
  • Process consortium: EnviDan A/S.
  • Architectural consultant: Henning Larsen Architects A/S
    Subconsultants: Klinges Tegnestue, Topotek 1 GmbH and Eva Koch

EIA consultant: Niras A/S

Legal advisor: Bech-Bruun Advokatpartnerselskab P/S

Client consultant: COWI A/S