Large amounts of white foam of unknown origin have been filling the Vamdrup wastewater treatment plant near Kolding since Wednesday. By Friday, the foam was flowing out into the Kongeå river.
The plant is operated by the utility company BlueKolding, which says it does not know where the foam is coming from. DR reports that the first white, cream-like foam appeared on Wednesday, and that the volume has grown every day since.
BlueKolding’s communications chief, Tue Knudsen, told DR that the sight is dramatic. He compared the plant to a bathtub that has gone wild. On Friday, the quantity had grown so large that foam was carried out of the facility and into the Kongeå.
Initial assessment: not dangerous
BlueKolding called in the environmental duty officer from Kolding Municipality to inspect the foam entering the river. According to Knudsen, the immediate assessment is that the foam is not dangerous. Samples showed only a small drop in the water’s oxygen content.
Knudsen told DR that people walking along the Kongeå and seeing the foam have no reason to be alarmed. BlueKolding has taken water and foam samples, and results expected within a few days should show what the foam is made of. Until then, its exact composition and cause remain unknown.
The company believes the foam originates in Vamdrup or the surrounding area, somewhere in the sewer system feeding the plant. No specific location or discharger has been identified. BlueKolding has therefore issued a public appeal, asking residents to report foam seen at manholes or elsewhere, on the number 76 36 36 36.
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Regional outlet JydskeVestkysten also reports on the incident, describing large quantities of mysterious foam filling the treatment plant near Vamdrup and running into the Kongeå. As noted by the newspaper, BlueKolding is working to locate the source and is seeking help from citizens to identify the cause.
Background from Kolding Municipality, in its wastewater plan Blå Plan last updated in 2025, describes the Vamdrup plant as a modern mechanical, biological and chemical treatment facility. It is located at Danmarksgade 21A in Vamdrup. Per the municipality, it receives wastewater from Vamdrup, Hjarup, Lunderskov and Jordrup, and its treated effluent is discharged into the Kongeå.
That discharge route explains why foam building up at the plant ends up in the river itself. No dedicated press release about the incident has been published by Kolding Municipality or BlueKolding, and the available information comes from statements reported by DR and JydskeVestkysten.
According to DR, the timing follows the foam’s sudden appearance on Wednesday and its rapid increase over the following days. BlueKolding contacted the municipal environmental duty officer once the foam began reaching the Kongeå, which led to the inspection and the public appeal this week.
