ALRESFORD STW - Winchester, Hampshire Wastewater Treatment Plant

ALRESFORD STW is a wastewater treatment plant located near Tichborne, Winchester, in Hampshire, England. It serves a population of around 5,633, placing it in the small-to-medium agglomeration category under UK regulations. The plant is situated inland, more than 50 km from the coast, and discharges into local watercourses that ultimately drain into the English Channel. As a UK-based plant, ALRESFORD STW is regulated under the Water Industry Act 1991 and must comply with the Urban Waste Water Treatment (England and Wales) Regulations 1994, which transpose the EU Urban Waste Water Treatment Directive. The plant's designed capacity is 1.00 (likely in megalitres per day or similar units), indicating a modest scale. The treated effluent from ALRESFORD STW is discharged into local rivers that feed into the River Itchen or similar chalk streams, which are ecologically sensitive habitats supporting diverse aquatic life, including salmonids and invertebrates. These waters eventually reach the Solent and the English Channel, making the plant's performance important for downstream water quality and marine ecosystems.

ALRESFORD STW discharges into the River Itchen catchment, a classic chalk stream renowned for its high biodiversity and clear, nutrient-poor waters. The River Itchen flows into Southampton Water and then the Solent, a critical migratory corridor for birds and fish. The plant's effluent must meet strict nutrient standards to protect these sensitive habitats from eutrophication.