ALANGE Wastewater Treatment Plant, La Zarza, Extremadura, Spain

ALANGE is a wastewater treatment plant located near La Zarza in the province of Badajoz, Extremadura, Spain. It serves a population of approximately 4,300 people, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant is situated inland, away from coastal areas, and its operations are part of the regional water management infrastructure in the Guadiana River basin. The plant provides secondary treatment, which is the minimum standard required by the EU directive for freshwater discharges from agglomerations of this size. With a designed capacity of 6,000 m³/day and an actual discharge volume of 779.36 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into the local watershed, which ultimately drains into the Guadiana River. The Guadiana flows southwest through Extremadura and into the Gulf of Cádiz (Atlantic Ocean). The plant plays a key role in protecting the Guadiana basin from untreated sewage, supporting water quality for downstream communities and ecosystems, including agricultural areas and wetlands along the river.

The plant discharges into the Guadiana River basin, which flows through Extremadura and into the Gulf of Cádiz. The Guadiana supports diverse aquatic life and is an important water source for irrigation in the region. Downstream areas include ecologically sensitive zones such as the Guadiana Estuary, which provides habitat for migratory birds and fish species. The plant's secondary treatment helps reduce nutrient loads that could otherwise contribute to eutrophication in the river and coastal waters.