Cardiff STW: Major Wastewater Treatment Plant Serving Cardiff, Wales

Cardiff STW is a large wastewater treatment plant located in Cardiff, the capital city of Wales, United Kingdom. Serving a population of approximately 846,265, it is one of the major treatment facilities in the region, managing municipal wastewater from the city and surrounding areas. As a plant serving a population equivalent well above 150,000, it falls under the EU Urban Waste Water Treatment Directive (91/271/EEC) as a 'large agglomeration', requiring advanced treatment to protect sensitive receiving waters. The plant's designed capacity is 1.00 (likely in megaliters per day or similar unit), indicating substantial infrastructure to handle high flows. The treated wastewater is discharged into the Bristol Channel, a major estuary and important ecological zone. The discharge supports the water quality of the Severn Estuary and downstream marine environment, which hosts diverse aquatic life and migratory fish species. The plant plays a key role in maintaining environmental standards in this coastal region.

Cardiff STW discharges into the Bristol Channel, which connects to the Severn Estuary and ultimately the Celtic Sea. This coastal environment supports diverse marine life, including fish, birds, and invertebrates, and is an important area for migratory species. The plant's operations help protect water quality in this ecologically sensitive estuary.