TP 368 of Karkolan kk Wastewater Treatment Plant, Kärkölä, Finland

TP 368 of Karkolan kk is a municipal wastewater treatment facility located in Kärkölä, within the Päijät-Häme region of southern Finland. The plant serves a population of around 3,700, classifying it as a small to medium agglomeration under Finnish and EU regulations. As an advanced treatment plant, it goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for facilities in sensitive areas like the Baltic Sea catchment. Finland's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC) requires advanced treatment for agglomerations over 10,000 people in sensitive areas, but smaller plants like this one often adopt similar standards to protect local waters. The plant's treated effluent is discharged into the local drainage network, which ultimately flows into the Kymijoki river basin and then to the Gulf of Finland, part of the Baltic Sea. This region is ecologically sensitive due to eutrophication risks, making advanced nutrient removal critical for downstream water quality and marine ecosystem health.

The plant discharges into the Kymijoki river basin, which drains into the Gulf of Finland, a sub-basin of the Baltic Sea. The Baltic Sea is highly sensitive to nutrient pollution, and advanced treatment at this plant helps reduce phosphorus and nitrogen loads that contribute to algal blooms and oxygen depletion. The surrounding Päijät-Häme region features numerous lakes and rivers that support diverse aquatic life and are important for recreation and fisheries.