STENLOSE Wastewater Treatment Plant, Stenløse, Denmark

STENLOSE is a wastewater treatment plant located in Stenløse, within Egedal Kommune, Region Hovedstaden, Denmark. The facility serves a population of approximately 11,922, classifying it as a medium-sized agglomeration under Danish and EU regulations. Its location near Copenhagen places it within a densely populated region with advanced environmental oversight. As a Danish plant, STENLOSE operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment for agglomerations of this size. The directive also requires more stringent treatment if the receiving waters are sensitive to eutrophication. The plant is expected to meet these regulatory standards to protect local water bodies. The treated effluent from STENLOSE likely discharges into local streams that flow into the Øresund, the strait between Denmark and Sweden connecting the Baltic Sea to the North Sea. This coastal discharge point underscores the importance of effective nutrient removal to prevent eutrophication in the sensitive Baltic Sea ecosystem. The plant plays a key role in maintaining water quality in the region.

STENLOSE discharges treated wastewater into local watercourses that drain into the Øresund, a major strait connecting the Baltic Sea to the North Sea. The Baltic Sea is a semi-enclosed, brackish sea highly sensitive to nutrient pollution, which can cause algal blooms and oxygen depletion. Effective treatment at STENLOSE helps reduce nitrogen and phosphorus loads, supporting the ecological health of this important marine environment.