LILLIANES Wastewater Treatment Plant, Perloz, Valle d'Aosta, Italy

LILLIANES is a wastewater treatment plant located in Perloz, within the Valle d'Aosta region of northern Italy. The facility serves a population of approximately 9,900 people, placing it in the medium agglomeration category under EU classification. Situated in the Alpine valley of Valle del Lys, the plant is part of the region's municipal infrastructure. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), agglomerations with a population equivalent between 2,000 and 10,000 are generally required to provide secondary treatment. Italy has transposed this directive into national law, and plants of this scale are expected to meet secondary treatment standards. The plant's discharge is regulated by the regional environmental authority of Valle d'Aosta. The treated effluent is discharged into the Lys River (Torrente Lys), a tributary of the Dora Baltea, which flows into the Po River and ultimately reaches the Adriatic Sea. The Lys River supports aquatic life in a mountainous watershed, and the plant's operation helps protect water quality in this ecologically sensitive Alpine environment.

The Lys River flows through the Valle del Lys, a glacial valley in the Italian Alps, before joining the Dora Baltea near Pont-Saint-Martin. The Dora Baltea is a major tributary of the Po River, which drains into the Adriatic Sea. This watershed supports diverse aquatic ecosystems, including fish species adapted to cold, fast-flowing waters. The plant's discharge must meet stringent standards to protect the river's ecological integrity, particularly given the region's importance for tourism and agriculture.