Stepnica Wastewater Treatment Plant | Secondary Treatment, Coastal Discharge

The Stepnica wastewater treatment plant is located in the town of Stepnica, within the gmina Stepnica in powiat goleniowski, województwo zachodniopomorskie, Poland. The facility serves a population of 1,413 and has a designed capacity of 6,000 m³/day, with an average discharge volume of 201.47 m³/day. The plant provides secondary treatment, which is the standard level required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary treatment for all discharges from agglomerations with a population equivalent (PE) between 2,000 and 10,000, and Stepnica's population of 1,413 falls below this threshold, but the plant still meets secondary treatment standards. The treated effluent is discharged into the local environment, which ultimately drains into the Baltic Sea. The plant's proximity to the coast (within 10 km) means its discharge can affect coastal water quality. The facility plays a key role in protecting the sensitive Baltic Sea ecosystem from nutrient pollution.

The Stepnica plant discharges treated wastewater into the local watershed, which flows into the Szczecin Lagoon and then into the Baltic Sea. The Baltic Sea is a semi-enclosed sea with limited water exchange, making it sensitive to nutrient inputs that can cause eutrophication. The plant's secondary treatment helps reduce organic load and nutrients, supporting the health of downstream aquatic habitats.