CHORLEY STW Wastewater Treatment Plant, Chorley, Lancashire

CHORLEY STW is a wastewater treatment plant located on German Lane in Charnock Richard, Chorley, Lancashire, England. It serves a population of around 65,677, classifying it as a medium-to-large agglomeration under UK regulatory frameworks. The plant is situated inland, approximately 50 km from the coast, and discharges into local watercourses that ultimately drain to the Irish Sea. As a UK plant, CHORLEY STW is regulated 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 the minimum standard, with tertiary treatment required if discharging into sensitive areas. The plant's designed capacity is 1. 00 (likely in megalitres per day or similar units), indicating a substantial infrastructure footprint. The treated effluent from CHORLEY STW enters the River Yarrow or its tributaries, which flow into the River Douglas and then to the Ribble Estuary, a key ecological zone supporting diverse birdlife and aquatic species. The Ribble Estuary is a site of international importance for migratory waterfowl and wading birds, making the plant's discharge quality critical for maintaining water quality and ecosystem health in this sensitive coastal environment.

CHORLEY STW discharges into the River Yarrow catchment, which flows into the River Douglas and ultimately the Ribble Estuary, a major coastal inlet of the Irish Sea. The Ribble Estuary supports internationally important populations of migratory birds and is a designated Site of Special Scientific Interest (SSSI) for its intertidal mudflats and saltmarshes. The plant's effluent quality is crucial for maintaining the ecological balance of this sensitive downstream environment, particularly regarding nutrient levels and dissolved oxygen.