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R&D project in tunnel cleaning

AxFlow Norway takes part in the development and testing of a more sustainable filter technology in the Bjørnegård tunnel outside Oslo. There is a strict focus on safety and maintenance in the 1100 tunnels of Norway. Tunnels must be cleaned often to maintain sight and make sure all signs are visible, in addition to keeping the lanes clean.

The tunnel is contaminated by car tires, breaks, oil, salt and more, and this needs to be regularly washed out to maintain safety. Which means that heavy metals, various oil compounds and microplastics pollute the cleaning water. AxFlow Norway has participated in an R&D project initiated by the The Norwegian Public Roads Administration, which aims to develop a more sustainable filtering of the cleaning water. By installing a total of three filter solutions, in addition to the existing sedimentation pool, the team is testing various ways to clean this water before letting it back into nature. This project is the first time all the solutions are tested in full scale inside a tunnel.

From component supplier to researcher
AxFlow Norway originally entered the project as a supplier and entrepreneur for the delivery of a pumping station and installing a system of bag filter connected to the standard sedimentation pool of the tunnel. In May 2018, The Norwegian Public Roads Administration (NPRA) invited us to join the R&D project "Purification of tunnel cleaning water" together with the Norwegian University of Science and Technology (NTNU) and ViaNova. Cleaning solutions were to be established and tested in connection with the existing cleaning system. AxFlow joined the project in August the same year.

Night shifts and thorough planning
Originally, the installations were to be done by the time of the opening of the Bjørnegård tunnel. Because of delays the work had to take place after the tunnel was started. The rest of the assembly and installations had to be done at night, 1-2 times a month, when it was possible to completely close the tunnel without creating larger conflicts for the traffic of the area. Fortunately, good communication and collaboration with ViaNova and NPRA lead to a successful completion of a complicated phase. Night shifts in a closed tunnel comes with strict regulations, and everyone involved is responsible for making sure the necessary equipment and tools are at hand. This also put pressure on the project members at AxFlow. Our project department planned every shift in detail and completed its part of the work in close collaboration with our instrumentation experts and service technicians.

Service Manager Lars Petter Borgen on night shift.

Reduced emissions of pollutants in the future – environment and community engagement

The NPRA requires two-step cleaning solutions for high-traffic tunnels. One sedimentation pool is longer enough, but as per today, the second stage has not been defined. In this project, we hope to find a satisfactory second step, but it may take three steps to reduce the emission of pollutants. Therefore, a number of filter solutions are tested. Then samples of the filtered water are sent to NTNU for further analysis.                                                                                                                     


       Aturia centrifugalpumps in the pumpstation. 

For AxFlow, the tunnel washing project in the Bjørnegård tunnel is an important investment on several levels. As a player in, and supplier of, fluid handling solutions, it is crucial for us to help develop solid and long-term solutions. Being part of Axel Johnson International, there are strict requirements that we simultaneously contribute to developing sustainable solutions in the industries we work in. For us, sustainable operations mean that we as a company must take responsibility for moving into the future in a sustainable way. Read more about the requirements we make for ourselves and our partners on our website.


Project manager Marius Eilertsen Skinlo shows the bag filters with the associated Grantcomputer loggers and Emerson Rosemount MAG gauges.

Text: Elisabet Janssen/Marius Eilertsen Skinlo, AxFlow Norway
All photos: Bjørn Aage Brygmann, AxFlow Norway 

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