OLSTED Wastewater Treatment Plant, Ølsted, Denmark

OLSTED is a wastewater treatment plant located in Ølsted, a town in Halsnæs Municipality, Region Hovedstaden, Denmark. The plant serves a population of 1,865 and is situated near the coast, reflecting its role in managing municipal wastewater in a coastal community. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. With a designed capacity of 2,391 m³/day and a current discharge volume of 369.52 m³/day, the plant operates well within its capacity. As a Danish facility, it complies with the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates advanced treatment for sensitive areas and larger agglomerations. The treated effluent is discharged into the local water environment, ultimately reaching the Kattegat sea via nearby coastal waters. The plant's advanced treatment helps protect the marine ecosystem from nutrient pollution, supporting biodiversity in the region. Its coastal location underscores the importance of stringent treatment to safeguard the Baltic Sea and adjacent waters.

The plant discharges into the Kattegat, a sea area connecting the Baltic Sea to the North Sea. This region supports diverse marine life, including fish, seabirds, and benthic habitats. Advanced treatment reduces nutrient loads, mitigating eutrophication risks in the sensitive coastal and marine environment.