Barton Stacey STW - Secondary Wastewater Treatment Plant in Test Valley, Hampshire

Barton Stacey STW is a wastewater treatment facility located in the village of Barton Stacey, within the Test Valley district of Hampshire, England. The plant serves a population of around 3,459 people, classifying it as a small agglomeration under UK and EU regulatory frameworks. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for inland freshwater discharges from agglomerations of this size. The designed capacity is 3,459 m³/day, and the actual discharge volume is 770.09 m³/day, indicating operational headroom. As a UK facility, it operates under environmental permits issued by the Environment Agency, ensuring compliance with discharge quality standards. The treated effluent is discharged into a local watercourse that ultimately drains into the River Test, a chalk stream renowned for its high ecological value and biodiversity. The River Test flows into the Solent, a major estuary on the south coast of England. The plant's operations help protect the sensitive aquatic habitats of the River Test and downstream marine environments.

Barton Stacey STW discharges into a tributary of the River Test, one of England's premier chalk streams known for its clear, nutrient-poor waters and diverse wildlife, including salmon and trout. The River Test flows into the Solent, a large estuary that supports important bird populations and marine habitats. The plant's secondary treatment and low discharge volume help maintain water quality in this ecologically sensitive catchment.