Nynäshamn Avloppsanläggning - Municipal Wastewater Treatment Plant in Nynäshamn, Sweden

Nynäshamn Avloppsanläggning is a municipal wastewater treatment plant located in Nynäshamn, a coastal town in Stockholms län, Sweden. The plant serves a population of approximately 23,770, placing it in the medium agglomeration category under EU classification. Its address at Oljehamnsvägen, Nynas Raffinaderi, indicates proximity to industrial facilities, including an oil refinery. As a Swedish plant, Nynäshamn Avloppsanläggning is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The directive also mandates more advanced treatment if the discharge enters sensitive areas, such as coastal zones or nutrient-sensitive waters. The plant's designed capacity is 1.00 (likely in thousands of cubic meters per day), suggesting it is sized to handle the local population and industrial contributions. The plant's treated effluent is discharged into the Baltic Sea, a brackish water body with limited water exchange, making it sensitive to nutrient pollution. The Baltic Sea faces challenges from eutrophication, and Swedish treatment plants play a key role in reducing nitrogen and phosphorus loads. The plant's coastal location within 50 km of the sea underscores the importance of effective treatment to protect marine ecosystems.

The plant discharges into the Baltic Sea, a semi-enclosed sea connected to the North Sea via the Danish straits. The Baltic Sea is highly sensitive to nutrient inputs, leading to eutrophication and algal blooms. The local watershed includes coastal streams and the surrounding Stockholm archipelago, which supports diverse aquatic life and serves as a critical habitat for fish and bird species. Effective wastewater treatment is essential to minimize nutrient loading and preserve the ecological balance of this fragile marine environment.