The new Ersmark Tunnel will be approximately 1.6 kilometers long and is the only tunnel on the stretch between Umeå and Skellefteå. We are delivering the equipment in April and the initial work is set to begin in May.

Swedish Hydro Solutions has previously undertaken several large-scale water treatment projects in cooperation with Implenia, including those for Johannelund and the work tunnel project in Hagalund, Stockholm - as well as the railway tunnel through central Varberg.

For the Ersmark Tunnel project, we have worked closely with Implenia to design and develop a comprehensive treatment solution. It includes pre-sedimentation, oil separation, pH adjustment, Swedish Hydro Solutions' patented dosing system HydroBox, mixers, lamella separators for efficient particle separation, and a final filtration system.

Once the water and other contaminants have been treated according to very strict requirements, the water can either be returned to the tunneling rigs or discharged into the recipient.

New for this project is that we measure and monitor nitrogen levels in real-time, including both nitrate and ammonium.

– It feels great that the design and development phase has gone so well, says Carl-William Kalholm at Swedish Hydro Solutions. The discharge requirements are stringent, and the tunnel will be driven through a mountain with an old landfill on top, so we have made a robust design to treat many different potential contaminants.

– The excellent cooperation with Implenia has resulted in two highly competent systems that we feel confident can handle both large water volumes as well as high concentrations of different contaminants, Carl-William says.

Photo: Patrick Degerman for Norbottniabanegruppen