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The first water turbine to recover energy in wastewater

12. February 2021

Solution provider


EnviDan specializes in environmental solutions within water resources, water supply, climate, energy and waste water. EnviDan has been on the market since 1995, and has build up an significant experience and knowledge in the environmental sector.

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With a desire to use the resources in wastewater, BlueKolding has established possibly the first water turbine in the world that recovers energy in wastewater. In collaboration with Aarsleff and BlueKolding, EnviDan has designed and projected the solution.

Where the outlet line from BlueKolding's central treatment plant disappears into Lillebælt – a strait between Funen and Jutland - a turbine plant will be established, which is the first of its kind in Denmark. The project ensures BlueKolding a maximum yield of the drop height of 35 m from the central treatment plant to Lillebælt at the same time as establishing a reliable plant. With the turbine system, approx. 25 % of the energy consumed when pumping the wastewater from Kolding to the central treatment plant is restored.

 Millions of cubic meters of treated wastewater provide renewable energy every single year

The water turbine is a good example of how existing resources can be utilized for the benefit of both BlueKolding and the environment. BlueKolding discharges 10-12 million cubic meters of treated wastewater from the central treatment plant in Agtrup per year.

With the new turbine, the many cubic meters can produce approx. eight percent of the amount of electricity that the central treatment plant in Agtrup uses annually - and that corresponds to approx. power consumption of 100 ordinary households and an annual reduction in CO2 emissions of 3,700 tons.

 Several treatment plants may have untapped potential

The energy produced is a product of pressure and flow, which is why the energy is 100 % climate neutral. If you have a treatment plant that diverts to the recipient via a line with a relatively large drop - and if the amount of water is relatively large, there is also potential for extracting large amounts of energy via a turbine plant from your outlet.

Building camouflaged as a stack of tree trunks

Extra effort was put into creating a building that blends in with nature. Architects from Tegnestuen Mejeriet A/S was responsible for the architecture of the turbine building and they have really succeeded. The building is camouflaged as a stack of tree trunks, and one must get very close to even discover that it is anything more than a pile of wood. The innovative building therefore received an honorable mention when the Municipality of Kolding at Architecture Day awarded the building as one of the 10 winning buildings and facilities in the municipality.