Psyttalia wastewater treatment plant serves over 5.2 million people in the Athens metropolitan area, Greece. It is located on Psyttalia Island near Piraeus, discharging treated effluent into the Saronikos Gulf.
Psyttalia is one of the largest wastewater treatment plants in Europe, serving the greater Athens region with a population equivalent of over 5.2 million. The plant is situated on Psyttalia Island in the Saronic Gulf, near the port of Piraeus, and is a critical component of the region's sanitation infrastructure. As a major facility serving a large agglomeration, Psyttalia operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires advanced treatment (tertiary) for discharges into sensitive areas. The plant's designed capacity is 1.00 million cubic meters per day, reflecting its role in handling the wastewater of Greece's capital and largest city. The treated effluent is discharged into the Saronikos Gulf, a semi-enclosed embayment of the Aegean Sea. The gulf supports diverse marine life and is an important recreational and economic zone for Athens and surrounding islands. Proper treatment is essential to protect water quality and coastal ecosystems in this densely populated and touristic region.
Environmental context
The plant discharges into the Saronikos Gulf, which connects to the Aegean Sea and ultimately the Mediterranean Sea. This coastal area is ecologically sensitive, supporting seagrass meadows, fish nurseries, and migratory seabirds. The gulf also receives runoff from the Athens urban area, making nutrient and pathogen removal critical to prevent eutrophication and protect public health.
Frequently asked questions
Psyttalia plant is located on Psyttalia Island in the Saronikos Gulf, near the port of Piraeus and the city of Athens, Greece.
The plant serves over 5.2 million people, covering the Athens metropolitan area and surrounding municipalities.
Treated effluent is discharged into the Saronikos Gulf, a coastal embayment of the Aegean Sea, via an outfall system.
As a large agglomeration in the EU, Psyttalia must comply with the Urban Waste Water Treatment Directive 91/271/EEC, which mandates advanced treatment for discharges into sensitive coastal waters.
For large agglomerations in sensitive areas like the Saronikos Gulf, tertiary treatment with nutrient removal is required to meet EU standards and protect marine ecosystems.