State-of-the-art WWTP built from scratch


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EnviDan is a full service environmental company offering professional solutions within the drinking water, wastewater, biogas and environment.

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In a consortium consisting of EnviDan, Jakobsen & Blindkilde and Strøm Hansen, a modern wastewater treatment plant in the municipality of Mariagerfjord is built to replace the current 10 WWTP.

The plant is situated in beautiful surroundings north of Hadsund, with scenery views of corn fields and forests, and will also in the future be the home office for all administrative personnel in Mariagerfjord Vand.

Since the WWTP is to be built from scratch the design and treatment solutions chosen were free of prior installations. This has resulted in a state of the art solution with a mix of innovative and well documented solutions. We hereby ensure optimal cleaning results using as little energy as possible.

The process tanks are among the largest circular tanks in Denmark, and when the plant is finished, we will not only have improved the cleaning process compared to earlier plants, we will also have provided the citizens of Mariagerfjord with a facility which is ready for future water volumes.

The fjord in Mariager cannot take any more water from WWTPs so to relieve the fjord all the treated wastewater is transported via a 12 km long pipe to the nearby ocean Kattegat, where it is taken even further, as a 4 km pipe takes the water far into the ocean. This improves the environment in and around Mariagerfjord.

Technical Specifications

Technically the wastewater is pumped to the WWTP by no less than 9 pressure pipes.  After grating, the sand is settled in round decanters separating the sand from the water without adding air. This ensures that the easily degradable carbon fraction is available in the process tanks, where it is a benefit to the cleaning process.

The process tanks are build according to the EnviFlex principle, which means that the tank is divided into 3, with both anaerobic, anoxic and aerobic sections. Aeration takes place with board aerators and stirring is ensured using frequency-controlled mixers. Combined with advanced online control and turbo blowers we provide the best cleaning results using a minimum of energy and consumables.

To minimize the sludge volume the new WWTP has a digester with a capacity of 2,000 m3, and the biogas from the digester is burned in a gas engine providing heat for the buildings and power to the power grid.

The 3 machinery buildings are connected via an engineers hall giving easy access to all plant facilities and keeping the most possible machinery as “dry installations”. Only when it is the most energy saving way, installations are submerged.

Motors are established with low energy motors and frequency regulators to minimize energy consumption.

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Gitte Nabe Kristensen
+45 27 15 01 07


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