Delsbo avloppsreningsverk - Advanced Wastewater Treatment Plant in Delsbo, Sweden

Delsbo avloppsreningsverk is a municipal wastewater treatment facility located in the village of Delsbo, within Hudiksvalls kommun in Gävleborgs län, Sweden. The plant serves a population of around 2,925, placing it in the small agglomeration category under EU regulations. The plant provides advanced treatment, which goes beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC). Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant has a designed capacity of 4,214 cubic meters per day and currently discharges approximately 459 cubic meters per day, indicating significant spare capacity. The treated effluent is discharged into a local watercourse that ultimately drains into the Baltic Sea via the Dellen lakes and the River Delångersån. The Baltic Sea is a brackish water body sensitive to eutrophication, making advanced nutrient removal critical for protecting its ecological health. The plant's location inland, over 10 km from the coast, reduces direct marine discharge risk.

The plant discharges into a local stream that flows through the Dellen lake system and into the Delångersån River, which empties into the Bothnian Sea, a part of the Baltic Sea. The Baltic Sea is highly sensitive to nutrient pollution, and advanced treatment at this plant helps reduce nitrogen and phosphorus loads that could contribute to algal blooms and oxygen depletion in coastal waters.