SAN MARTIN NORESTE Wastewater Treatment Plant, San Martín de Valdeiglesias, Spain

SAN MARTIN NORESTE is a wastewater treatment facility located in San Martín de Valdeiglesias, within the Comunidad de Madrid, Spain. The plant provides secondary treatment for a small population of 63 residents, with a designed capacity of 5,000 cubic meters per day, indicating significant reserve capacity for future growth or seasonal demand. As a secondary treatment plant, it meets the minimum treatment standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary treatment for all discharges from agglomerations with a population equivalent above 2,000, and this plant's current load is well below that threshold, reflecting its role in a small rural community. The treated effluent is discharged into the local watershed, which ultimately drains into the Alberche River, a tributary of the Tagus River. The Tagus River flows westward through Spain and Portugal, discharging into the Atlantic Ocean near Lisbon. The plant's inland location, over 50 km from the coast, reduces direct marine impact, but its discharge contributes to the overall water quality of the Tagus basin, which supports diverse aquatic life and agricultural water use.

The plant discharges into the Alberche River basin, a tributary of the Tagus River, which flows into the Atlantic Ocean. The Tagus basin is a critical water resource for central Spain and Portugal, supporting irrigation, drinking water supply, and diverse freshwater ecosystems. The plant's secondary treatment helps protect downstream water quality, though the small population served limits the overall nutrient load.