Advancing micropollutant treatment in wastewater: SUEZ selected by Kalundborg Forsyning, a public water utility in Denmark

Supporting advanced wastewater treatment in Denmark

SUEZ has been selected by Kalundborg Forsyning to design and deliver a new quaternary treatment stage at the Kalundborg Central Wastewater Treatment Plant in Denmark. The installation will reduce micropollutants in treated wastewater discharged into Storebælt, the strait between the Danish islands of Zealand and Funen. The overall project will also increase the plant’s treatment capacity and support Kalundborg Forsyning in meeting stringent environmental requirements.

Advanced treatment to protect the marine environment

Denmark has long applied stringent wastewater treatment standards, particularly for the removal of nitrogen and phosphorus. These requirements are now expanding to address micropollutants and industrial residues, supporting the deployment of additional treatment technologies across the country.

The solution developed for Kalundborg Forsyning will combine two ozone injection lines, supplied by three ozone generators, with eight granular activated carbon filters. Digital optimisation technologies will support the operation of the new treatment stage.

The installation is designed to deliver robust treatment performance over the long term, while optimising operating costs and carbon performance, and limiting the operational intervention required.

By combining environmental performance with operational efficiency, the modernised Kalundborg Central Wastewater Treatment Plant will contribute to protecting water resources and the marine environment.

Supporting the transition towards advanced wastewater treatment

The contract will be executed over three years and builds on SUEZ’s 35-year presence in Denmark and more than ten years of experience in micropollutant treatment in the country.

SUEZ currently has six municipal and industrial wastewater treatment plants dedicated to micropollutant removal either in operation or under construction in Denmark. The Kalundborg project further expands the Group’s portfolio of advanced wastewater treatment references in the Danish market.

The revised European Urban Wastewater Treatment Directive introduces new requirements for the removal of micropollutants through quaternary treatment. EU Member States are required to transpose the directive into national law by July 2027, with progressive implementation targets thereafter. Through its proven treatment technologies, operational expertise and established Scandinavian footprint, SUEZ is well positioned to support water utilities and municipalities as they prepare for these new requirements.