Overkalix avr Wastewater Treatment Plant, Överkalix, Sweden

Overkalix avr is an advanced wastewater treatment plant located in Överkalix, a small town in Norrbottens län, northern Sweden. The plant serves a population of approximately 1,775 residents, reflecting its role in a sparsely populated region. As an advanced treatment facility, it provides a high level of pollutant removal, which is essential for protecting the sensitive subarctic environment. The plant has a designed capacity of 4,000 cubic meters per day and currently discharges 278.64 cubic meters of treated wastewater daily, indicating significant spare capacity. Under Swedish regulations, which implement the EU Urban Waste Water Treatment Directive (91/271/EEC), advanced treatment is required for discharges into sensitive areas. The plant's advanced treatment level suggests it meets stringent standards for nutrient removal, particularly phosphorus and nitrogen, which are critical in northern water bodies. The treated effluent from Overkalix avr likely discharges into a local watercourse that flows into the Kalix River, one of Sweden's last unregulated major rivers, known for its pristine waters and rich salmon populations. The Kalix River ultimately drains into the Gulf of Bothnia, a brackish sea arm of the Baltic Sea. The plant's advanced treatment helps protect this ecologically sensitive river system and the downstream marine environment from eutrophication.

Overkalix avr discharges into a local watercourse that feeds the Kalix River, a free-flowing river in northern Sweden that supports diverse aquatic life, including Atlantic salmon and brown trout. The Kalix River flows into the Gulf of Bothnia, a brackish sea with limited water exchange, making it vulnerable to nutrient pollution. The plant's advanced treatment reduces nutrient loads, helping to prevent algal blooms and maintain water quality in this ecologically sensitive region.