Impianto Villaggio San Marco Wastewater Treatment Plant, Piazza Armerina, Sicily

Impianto Villaggio San Marco is a wastewater treatment plant located in Piazza Armerina, a town in the province of Enna, Sicily, Italy. The facility serves a small population of 235 residents and operates with a designed capacity of 250 m³/day, currently utilizing 46.52 m³/day of that capacity. The plant provides primary treatment, which involves physical processes such as sedimentation to remove settleable solids. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), small agglomerations with a population equivalent below 2,000 are generally required to provide appropriate treatment, though primary treatment may be considered sufficient depending on the sensitivity of the receiving environment. The treated effluent is discharged into local watercourses that ultimately drain into the Mediterranean Sea. The plant's location in inland Sicily, over 10 km from the coast, reduces direct marine impact, but the receiving waters contribute to the broader watershed of the Ionian Sea, supporting local aquatic ecosystems and agricultural water reuse potential.

The plant discharges into inland watercourses that flow through the Sicilian hinterland, eventually reaching the Ionian Sea. The local watershed supports diverse aquatic life and is important for regional biodiversity. The Mediterranean Sea downstream is a semi-enclosed basin with sensitive marine ecosystems, where nutrient inputs can contribute to eutrophication. The plant's primary treatment level means that nutrient removal is limited, which may affect downstream water quality.