HAVNSO Wastewater Treatment Plant, Havnsø, Denmark

HAVNSO is a wastewater treatment plant located in Havnsø, a coastal town in Kalundborg Kommune, Region Sjælland, Denmark. The plant serves a population of 2,727 and has a designed capacity of 4,200 cubic meters per day, with an average discharge volume of 419.42 cubic meters per day. As an advanced treatment facility, HAVNSO provides a higher level of purification beyond secondary treatment, which is typical for plants in sensitive coastal areas under the EU Urban Waste Water Treatment Directive. Denmark implements strict nutrient removal standards to protect the Baltic Sea and inner coastal waters. The plant discharges treated wastewater into the local coastal environment near Havnsø Havn. This area drains into the Kattegat sea region, which is part of the larger Baltic Sea catchment. The advanced treatment helps minimize nutrient loading and protects marine ecosystems in this ecologically sensitive coastal zone.

HAVNSO discharges into the coastal waters of the Kattegat, a transitional sea between the North Sea and the Baltic Sea. This area supports diverse marine life, including fish spawning grounds and migratory bird habitats. The advanced treatment reduces nitrogen and phosphorus loads, which is critical for mitigating eutrophication in the Baltic Sea basin.