CHIOS Wastewater Treatment Plant, Chios, Greece

The CHIOS wastewater treatment plant is situated in the city of Chios on the island of Chios, part of the North Aegean region of Greece. The plant serves a population equivalent of 29,400, classifying it as a medium-sized agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). As a Greek facility, the plant operates under the EU UWWTD (91/271/EEC), which requires secondary treatment for discharges into coastal waters. For agglomerations of this size, the directive mandates at least secondary treatment, with tertiary treatment required if the receiving waters are designated as sensitive areas. The plant discharges into the Aegean Sea, a semi-enclosed sea with limited water exchange, making it sensitive to nutrient pollution. The surrounding marine environment supports diverse aquatic life, including seagrass meadows and fish populations. Proper treatment is essential to prevent eutrophication and protect coastal ecosystems.

The plant discharges into the Aegean Sea, which is part of the Eastern Mediterranean basin. The Aegean Sea is a semi-enclosed sea with limited tidal flushing, making it vulnerable to nutrient enrichment from wastewater. The coastal waters around Chios support important marine habitats, including seagrass beds and nursery grounds for fish. Effective wastewater treatment is critical to maintaining water quality and protecting the ecological balance of this sensitive marine environment.