IDL_MARINELLA Wastewater Treatment Plant, Montegiovi, Toscana, Italy

IDL_MARINELLA is a municipal wastewater treatment plant located in Montegiovi, a frazione of Castel del Piano in the Toscana region of Italy. The plant serves a population of 2,405 and is part of the Unione dei Comuni Montani Amiata Grossetana, a union of mountain municipalities in the Grosseto province. Its inland location places it within the hilly terrain of the Amiata area, a region known for its natural springs and forested landscapes. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 4,500 m³/day and an actual discharge volume of 476.11 m³/day, the plant operates well below its capacity, indicating ample headroom for future growth or seasonal variations. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), secondary treatment is the minimum requirement for inland freshwater discharges, and this plant meets that standard. The treated effluent is discharged into local watercourses that ultimately drain into the Tyrrhenian Sea via the Ombrone River basin. The plant plays a key role in protecting the region's water quality, particularly the streams feeding into the Ombrone, which supports diverse aquatic life and is used for irrigation and recreation. Its operation helps maintain the ecological health of the Amiata area, a region of significant natural and touristic value.

The plant discharges into small tributaries of the Ombrone River, which flows south through the Grosseto plains before entering the Tyrrhenian Sea near the Maremma Natural Park. The Ombrone basin supports a variety of fish species and migratory birds, and its delta is an ecologically sensitive area. The plant's secondary treatment reduces organic pollution, helping to preserve water quality in this agriculturally and touristically important watershed.