THORNBURY STW Wastewater Treatment Plant, Old Passage, England

THORNBURY STW is a wastewater treatment plant serving the community of Old Passage in South Gloucestershire, England. It is situated near the Severn Bridge, a major infrastructure landmark, and handles wastewater from a population of around 13,343 people. The plant is part of the UK's wastewater infrastructure, which is regulated under the Urban Waste Water Treatment Regulations (transposing the EU Urban Waste Water Treatment Directive). As a medium-sized agglomeration serving between 10,000 and 15,000 people, the plant is expected to provide at least secondary treatment under UK regulations. The designed capacity is 1.00 (likely in megaliters per day or similar unit), indicating the plant's scale. Typical plants of this size employ biological treatment stages to meet discharge standards. The plant's treated effluent is discharged into the local water environment, ultimately reaching the Severn Estuary, a major tidal estuary with significant ecological importance. The estuary supports diverse aquatic life and is a key migratory route for fish. The plant's operations are subject to permits issued by the Environment Agency to ensure compliance with water quality standards and protect the downstream ecosystem.

THORNBURY STW discharges into the Severn Estuary, which is a large tidal estuary connecting to the Bristol Channel and the Atlantic Ocean. The estuary is ecologically sensitive, supporting diverse bird populations and fish species such as salmon and eels. The plant's location within 50 km of the coast means its discharge can influence coastal water quality, making treatment standards critical for protecting marine life.