Overview
Castelnaudary Estambigou is a secondary treatment plant in Castelnaudary, Occitanie, France, serving about 2,500 people. It discharges treated wastewater into local waterways under EU regulatory standards.
Castelnaudary Estambigou is a municipal wastewater treatment plant located in Castelnaudary, a town in the Occitanie region of southern France. The plant serves a population of approximately 2,500 and operates with secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (UWWTD) for agglomerations of this size. The facility has a designed capacity of 6,500 cubic meters per day and currently discharges an average volume of about 452 cubic meters per day. As a secondary treatment plant, Castelnaudary Estambigou removes organic matter and suspended solids through biological processes. The plant's performance is regulated under French national law transposing the EU UWWTD, which mandates secondary treatment for all inland discharges from agglomerations above 2,000 population equivalent. The plant's capacity utilization is well below its design capacity, indicating it has room to accommodate future growth. The treated effluent from Castelnaudary Estambigou is discharged into the local watershed, which ultimately drains into the Mediterranean Sea via the Aude River system. The plant plays a key role in protecting the water quality of the Canal du Midi, a UNESCO World Heritage site nearby, and the surrounding aquatic ecosystems. By reducing organic pollution and nutrients, the facility helps maintain the ecological health of the region's rivers and coastal waters.
Environmental context
The plant discharges into the Aude River basin, which flows through the Occitanie region and empties into the Mediterranean Sea near Narbonne. The receiving waters support diverse aquatic life, including fish species such as the European eel, and are part of a network of rivers and canals that sustain local agriculture and tourism. The Canal du Midi, a historic waterway, is also in proximity, making nutrient and pollutant control critical to preserving its ecological and cultural value.
Frequently asked questions
The plant is located on D 6113 in Castelnaudary, in the Aude department of the Occitanie region, southern France.
The plant serves approximately 2,533 people, classifying it as a small agglomeration under EU wastewater regulations.
The treated effluent is discharged into the local watershed, which flows into the Aude River and eventually reaches the Mediterranean Sea.
The plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), transposed into French law, which requires secondary treatment for inland discharges from agglomerations over 2,000 population equivalent.
For small agglomerations in France, secondary treatment (biological treatment) is the standard requirement under the EU UWWTD, ensuring removal of organic matter and suspended solids.
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