Overview
Cercal do Alentejo wastewater treatment plant serves about 3,000 people in Santiago do Cacém, Portugal, with secondary treatment. It discharges approximately 500 m³/day of treated effluent into the local watershed.
Cercal do Alentejo is a secondary-level wastewater treatment plant located near the village of Cercal, in the municipality of Santiago do Cacém, Setúbal District, Portugal. The facility serves a population of approximately 3,000 residents and has a designed capacity of 3,000 m³/day, with an average discharge volume of about 500 m³/day. As a secondary treatment plant, it meets the standard requirements under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary biological treatment for communities with a population equivalent between 2,000 and 10,000, which aligns with the plant's scale. The plant is operated as part of Portugal's municipal wastewater infrastructure, overseen by national water authorities. The treated effluent is discharged into the local watershed, which ultimately drains into the Atlantic Ocean via the Mira River or nearby coastal streams. The region is characterized by Mediterranean climate and agricultural landscapes, and the plant plays a role in protecting local water quality and downstream ecosystems.
Environmental context
The plant discharges into the Mira River basin, which flows southwest into the Atlantic Ocean near Vila Nova de Milfontes. The downstream environment includes estuarine and coastal habitats that support diverse aquatic life, including migratory fish species. The region's water bodies are ecologically sensitive due to seasonal flows and agricultural runoff, making consistent treatment important for maintaining water quality.
Frequently asked questions
The plant is located at Monte das Sesmarias, Azinhaga das Sesmarias, in the village of Cercal, within the municipality of Santiago do Cacém, Setúbal District, Portugal.
The plant serves approximately 3,000 residents in the Cercal area and surrounding communities.
The treated effluent is discharged into the local watershed, which flows into the Mira River and eventually reaches the Atlantic Ocean.
The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive for agglomerations of this size.
The plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), transposed into Portuguese law. For a population of 3,000, secondary treatment is mandatory, and the plant's discharge must meet quality standards to protect receiving waters.
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