THARSIS Wastewater Treatment Plant, El Cerro de Andévalo, Andalucía

THARSIS is a wastewater treatment plant located in El Cerro de Andévalo, in the Andévalo comarca of Huelva, Andalucía, Spain. The plant serves a population of 3,500 and is situated inland, more than 10 km from the coast. It is currently closed, with no operational status. The plant provided secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity of 3,500 m³/day matches the population served, indicating appropriate sizing. The discharge volume is 634.37 m³/day. The treated effluent from THARSIS likely discharges into local watercourses that drain into the Guadiana River basin, eventually reaching the Gulf of Cádiz in the Atlantic Ocean. The plant's operation helped protect the region's water quality and aquatic ecosystems.

THARSIS is located in the Andévalo region, part of the Guadiana River basin. The Guadiana River flows southward to the Gulf of Cádiz, supporting diverse aquatic life and important migratory bird species. The plant's secondary treatment reduces organic pollutants and nutrients, helping to maintain the ecological health of the downstream water bodies.