Sara Toustrup Kristensen

May 1, 2025

Innovative pre-study: Removing micropollutants from wastewater

New Swedish micropollutant pre-study in wastewater treatment will be setting a precedent for future water treatment projects.

Stockholm city

Together with Ramboll and Holinger, Stockholm Vatten is undertaking a crucial project to strengthen its wastewater treatment capabilities, driven by the new EU Urban Wastewater Directive. This directive mandates wastewater treatment plants above a certain size to implement micropollutant removal by 2033-2045. Recognizing the importance of this initiative, Stockholm Vatten aims to be one of the first large wastewater treatment plants (WWTP) in Sweden to meet these requirements by the end of 2033.

Ramboll will be leading a pre-study project at Henriksdal Wastewater Treatment Plant with local water treatment experts with support from Holinger, providing expertise from their many full-scale projects in Switzerland.

Exploring advanced treatment technologies at Henriksdal WWTP

The primary objective of the Henriksdal pre-study project is to develop a comprehensive understanding of various advanced treatment technologies. This includes assessing their performance, footprint in terms of energy and chemical consumption, waste products, and overall costs. The pre-study aims to provide a solid foundation for deciding which technology to adopt for micropollutant removal, and to facilitate further design and implementation.

One significant challenge is the underground location of the Henriksdal plant. The plant is built into a mountain with residential buildings built on top, leaving little space for expansion and thus a risk of high excavation costs. Therefore, the project plans to utilize existing spaces and structures as much as possible. Three advanced treatment solutions will be developed and compared using a multi-criteria analysis, considering factors such as cost (CAPEX and OPEX), sustainability, carbon footprint, logistics, and operational aspects.

Although this effort comes with significant costs, it is expected to drive economic growth and have a high impact on water quality.

“I am very pleased that we are including sustainability and carbon footprint in the comparison between alternative solutions, since these treatment technologies have an environmental impact. So, we need to make wise decisions on how to reduce pollution of our waters with as low consumption of fossil resources and energy as possible.”

Johanna Grim
Project manager, Ramboll Water

Through close collaboration between Ramboll, Holinger, and Stockholm Vatten, along with parallel pilot trials, the project tackles challenges related to the existing plant's structure and the uncertainties in the legal framework for micropollutant removal. The Henriksdal project results will thus provide valuable insights into treatment technologies, design parameters, and project methodologies for future projects.

With this project, Ramboll, Holinger and Stockholm Vatten showcase advanced treatment in a complex setting, highlighting effective treatment technologies and collaborative project methodologies in a Nordic context.

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Reviving Oslofjorden: Removal of Micropollutants and Nitrogen in Wastewater

Across four innovative Norwegian projects, Ramboll’s global water experts are collaborating with external partners and clients to significantly improve the health of Oslofjorden.

Oslofjorden

Want to know more?

  • Johanna Grim

    Team Lead

    +46 70 484 01 56

    Johanna Grim
  • René Hoeijmakers

    Global Division Director

    +31 6 83191061

    René Hoeijmakers