Savudrija Wastewater Treatment Plant: Coastal Primary Treatment in Istria, Croatia

The Savudrija wastewater treatment plant serves the coastal town of Savudrija in Istria County, Croatia. Located near the Adriatic Sea, the facility is designed with a capacity of 15,000 cubic meters per day, reflecting the seasonal population fluctuations typical of tourist destinations in the region. As a coastal plant within 10 km of the sea, its treatment level and discharge practices are critical for protecting marine water quality. The plant currently operates with primary treatment only. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), agglomerations of this scale (over 10,000 population equivalent) discharging into coastal waters are generally required to have at least secondary treatment, with more stringent requirements for sensitive areas. Particularly given its coastal location. The treated effluent from Savudrija is discharged into the northern Adriatic Sea, a semi-enclosed basin with limited water exchange. The Adriatic Sea supports diverse marine ecosystems, including seagrass meadows and fish nurseries, and is an important area for tourism and fisheries. Proper wastewater treatment is essential to prevent eutrophication and protect coastal water quality in this ecologically sensitive region.

The Savudrija plant discharges into the northern Adriatic Sea, a shallow basin that receives freshwater from the Po River and other Italian and Balkan rivers. The Adriatic Sea supports diverse marine life, including seagrass meadows and fish spawning grounds, and is a major tourist destination. Nutrient inputs from untreated or partially treated wastewater can contribute to algal blooms and hypoxia, threatening local fisheries and tourism. The plant's coastal location makes its treatment performance critical for maintaining the ecological health of this semi-enclosed sea.