COLMENAREJO ESTE Wastewater Treatment Plant, Galapagar, Spain

COLMENAREJO ESTE is a municipal wastewater treatment plant located in Galapagar, within the Comunidad de Madrid, Spain. The facility serves a population of 648 and operates with 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 plant has a designed capacity of 6,000 m³/day and currently discharges 686.18 m³/day of treated wastewater. As a secondary treatment plant, COLMENAREJO ESTE removes organic matter and suspended solids through biological processes, meeting the effluent quality standards set by Spanish regulations. The plant is part of the regional wastewater infrastructure managed by the Comunidad de Madrid, which oversees compliance with EU directives and national water laws. The treated effluent from COLMENAREJO ESTE is discharged into a local watercourse that eventually drains into the Guadarrama River, a tributary of the Tagus River. The Tagus River flows westward through Spain and Portugal, emptying into the Atlantic Ocean near Lisbon. The plant's operation helps protect the Guadarrama River and downstream ecosystems from pollution, supporting aquatic life and water quality in the region.

The plant discharges into a local stream that feeds the Guadarrama River, a key tributary of the Tagus River basin. The Tagus River is the longest river in the Iberian Peninsula, flowing through central Spain and Portugal to the Atlantic Ocean. The downstream environment supports diverse aquatic species and provides water for agriculture and urban use. The plant's secondary treatment reduces organic load and suspended solids, helping maintain ecological balance in the watershed.