Carrizo de la Ribera Wastewater Treatment Plant - Carrizo, Castilla y León, Spain

The Carrizo de la Ribera wastewater treatment plant is located in the municipality of Carrizo, within the province of León, in the autonomous community of Castilla y León, Spain. The plant serves a population of approximately 9,000 residents and has a designed capacity of 9,000 cubic meters per day, with an average discharge volume of 465.75 cubic meters per day. As a secondary treatment facility, the plant meets the requirements of the European Union's Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary biological treatment for agglomerations with a population equivalent between 2,000 and 10,000 in inland areas. The plant's operational context aligns with this regulatory framework, ensuring that treated effluent meets quality standards before discharge. The plant discharges treated wastewater into a local watercourse that ultimately drains into the Duero River basin, one of the major river systems in the Iberian Peninsula. The Duero River flows westward through Spain and Portugal, emptying into the Atlantic Ocean at Porto. The plant plays a key role in protecting the local aquatic environment and downstream water quality in the Duero basin.

The Carrizo de la Ribera plant discharges into a tributary of the Duero River, which flows through the Castilla y León region before entering Portugal and reaching the Atlantic Ocean. The Duero basin supports diverse aquatic life and is an important agricultural and ecological corridor. Secondary treatment helps reduce organic pollutants and nutrients, mitigating eutrophication risks in downstream water bodies.