STENLILLE Wastewater Treatment Plant, Stenlille, Denmark

STENLILLE is a wastewater treatment plant located in Stenlille, Sorø Municipality, Region Sjælland, Denmark. It serves a population of 2,580 and is part of the country's municipal wastewater infrastructure. The plant is situated inland, more than 10 km from the coast, and its operations are integrated into the local water management system. The plant provides advanced treatment, which goes beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 6,800 cubic meters per day and a current discharge volume of 773.27 cubic meters per day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local water bodies that eventually drain into the Baltic Sea via the region's river systems. The plant plays a key role in protecting the downstream aquatic environment, including streams and lakes in the Suså River basin, which supports diverse wildlife and recreational activities.

The plant discharges into local watercourses that feed into the Suså River system, which flows into the Baltic Sea via Karrebæk Fjord. This watershed supports a variety of aquatic life and is important for regional biodiversity. The advanced treatment helps minimize nutrient loading, protecting downstream ecosystems from eutrophication and maintaining water quality in the sensitive Baltic Sea environment.