In June 2022, the last section of the Inner Harbor in Norrköping was demolished to enable the development of the new neighborhood. Skeppsdockan has an industrial heritage dating back to the 18th century. During the 19th century, the area became a hub for gas production, and a coal gas plant operated there until the mid-1980s.

Following the demolition, extensive soil investigations and risk assessments revealed contamination from previous activities. This formed the basis for a major remediation project focused on managing environmental risks and enabling future construction.

Water treatment – a key part of remediation

In spring 2025, Swedish Hydro Solutions was contacted by Peab, which is responsible for part of the remediation work, to assist with water treatment. Remediation projects often generate large volumes of water, primarily from precipitation and groundwater infiltration, which can spread pollutants if not properly managed.

– In this particular project, Peab needs to excavate below the groundwater level because contaminants are found deep in the soil. Analyses have shown elevated levels of metals, cyanides, PAHs, and benzene. Water treatment is therefore crucial to prevent these pollutants from reaching the Motala River, where the water is discharged, says Erik Tholén, Project Manager at Swedish Hydro Solutions.

The treatment system

The system is designed for a flow rate of up to 10 m³/h and meets strict environmental requirements. Water is pumped from a constructed sedimentation pond and treated through several stages to ensure effective treatment:

• pH-Adjustment
• Flocculation and precipitation of particles and metals in a HydroBox (20-foot container)
• Sedimentation in a lamella clarifier
• Filtration through sand filters and adsorption with activated carbon to reduce hydrocarbons and cyanides

The system was delivered during October and will remain in operation until late spring 2026.