Pulborough STW - Wastewater Treatment Plant Serving Horsham, West Sussex

Pulborough STW is a wastewater treatment plant located near Pulborough in West Sussex, England, serving the Horsham area. The facility handles wastewater for a population equivalent of approximately 8,538, classifying it as a small to medium agglomeration under UK regulatory frameworks. As a UK wastewater treatment plant, Pulborough STW operates under the Urban Waste Water Treatment (England and Wales) Regulations, which transpose the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this size, secondary treatment is typically required, with additional nutrient removal if discharging into sensitive areas. The treated effluent from Pulborough STW is discharged into the local water environment, likely into a tributary of the River Arun, which flows south through the South Downs National Park and into the English Channel at Littlehampton. The receiving waters support diverse aquatic life and are important for regional biodiversity.

The plant discharges into the River Arun catchment, which flows through the South Downs to the English Channel. The river supports salmonid fisheries and is designated as a Site of Special Scientific Interest (SSSI) in parts. Downstream, the Arun estuary provides habitat for wading birds and migratory fish. Nutrient management is critical to prevent eutrophication in the coastal zone.