ELJAS Wastewater Treatment Plant, Eljas, Extremadura, Spain

ELJAS is a municipal wastewater treatment plant located in Eljas, a town in the province of Cáceres, Extremadura, Spain. The plant serves a population of around 3,200, typical of a small agglomeration in rural western Spain near the Portuguese border. The plant provides secondary treatment, which is the standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size discharging into freshwater. The designed capacity is 3,990 m³/day, and the current discharge volume is approximately 580 m³/day, indicating ample capacity headroom. The treated effluent is discharged into the local watershed, which drains into the Tagus River basin via the Erjas River. The Tagus River flows westward through Portugal to the Atlantic Ocean near Lisbon. The plant's operation helps protect downstream aquatic ecosystems and water quality in the Tagus basin.

The plant discharges into the Erjas River, a tributary of the Tagus River, which flows through Spain and Portugal to the Atlantic Ocean. The Tagus basin supports diverse aquatic life and is an important water resource for both countries. Secondary treatment reduces organic pollutants and suspended solids, helping to maintain ecological balance in the river system.