IRUNA DE OCA Wastewater Treatment Plant, Nanclares de la Oca, Spain

IRUNA DE OCA is a wastewater treatment plant located in Nanclares de la Oca (Langraiz Oka), within the municipality of Iruña de Oca in the province of Álava, Basque Country (Euskadi), Spain. The plant serves a population of approximately 6,800 people, placing it in the small-to-medium agglomeration category under EU classification. As a Spanish facility, the plant operates under the national transposition of the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations between 2,000 and 10,000 population equivalent, the directive requires appropriate treatment (secondary or equivalent) before discharge. The plant's treatment process and capacity details are not publicly available in this dataset, but the regulatory framework ensures compliance with European standards for inland freshwater discharges. The treated effluent from IRUNA DE OCA is discharged into the local hydrological network, which ultimately drains into the Zadorra River, a tributary of the Ebro River. The Ebro River flows into the Mediterranean Sea via the Ebro Delta, an ecologically significant area supporting diverse aquatic life and migratory bird populations. The plant's inland location and moderate scale contribute to its role in protecting local water quality in the Basque Country.

The plant discharges into the Zadorra River basin, which flows into the Ebro River and eventually reaches the Mediterranean Sea via the Ebro Delta. The Ebro Delta is a critical habitat for numerous bird species and supports extensive rice farming and fishing industries. The plant's treatment helps maintain water quality in the Zadorra and Ebro systems, which are important for both ecological health and downstream human uses.