ALOSNO Wastewater Treatment Plant, Alosno, Andalucía, Spain

ALOSNO is a wastewater treatment plant located in Alosno, a municipality in the El Andévalo region of Huelva, Andalucía, Spain. The plant serves a population of approximately 3,500 residents, reflecting its role in managing domestic wastewater for this inland community. Its location near the border with Portugal places it within the Guadiana River basin, a significant watercourse in the Iberian Peninsula. The plant employs advanced treatment processes, which go beyond the secondary treatment mandated by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 3,500 m³/day and an actual discharge volume of 634.37 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. As a Spanish plant, it is subject to national regulations transposing EU directives, overseen by regional authorities in Andalucía. The treated effluent from ALOSNO ultimately drains into the Guadiana River, which flows southward to the Gulf of Cádiz in the Atlantic Ocean. This river supports diverse aquatic ecosystems and is an important migratory corridor for fish species. The advanced treatment level helps protect water quality in the Guadiana, reducing nutrient loads and safeguarding downstream habitats.

ALOSNO discharges treated wastewater into the Guadiana River basin, which flows through southwestern Spain and Portugal before emptying into the Gulf of Cádiz, Atlantic Ocean. The Guadiana supports a variety of aquatic life, including endemic fish species and migratory birds. The advanced treatment at this plant helps minimize nutrient pollution, protecting the river's ecological health and the sensitive estuarine environments near its mouth.