Municipal: Harestua, Norway


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Project Name:
Harestua Wastewater Treatment Plant

Oppland County, Norway

Type of Plant:
Municipal - Retrofit

Technology Used:
Biowater CFAS®

Biomedia Used:
Biowater BWT-X®

Operational Since:


The Challenge

The Harestua STP plant was a traditional Norwegian STP with headworks (screen and sandtrap), primary settling, chemical precipitation of phosphorous and a final clarifier. The municipality was upgrading to accommodate increased load and new requirements for BOD/COD removal. The plant had space constraints and wanted to use their existing tankage.


The Design

Harestua decided on the Biowater CFAS® Combined Fixed Film Activated Sludge system. The CFAS® was chosen because Harestua could use their existing tankage and still meet and/or exceed treatment requirements for the plant. In addition, this process offered room for additional expansion in the future. The primary settling tanks were used for the biological CFAS® stage and the final clarifier was used for the Lamella and DAF as well as sludge storage.



A turnkey project was delivered. The Harestua contract was split into three different projects, M1, M2 & M3. M1 is all of the mechanical installations for the primary works, sludge dewatering and storage. The M2 project is the biological CFAS® stage and M3 is the lamella DAF with chemical precipitation of phosphorus.

Harestua St

The Biowater CFAS® (IFAS) process utilizes the benefits of a traditional activated sludge process combined with a biological fixed-film system to create a highly efficient wastewater treatment plant in a much smaller footprint.