NARBERTH WES STW - Secondary Wastewater Treatment Plant near Canaston Bridge, Pembrokeshire

NARBERTH WES STW (Wastewater Treatment Works) is a secondary-level treatment facility located near Canaston Bridge in Pembrokeshire, Wales, United Kingdom. The plant serves a population equivalent of 2,514 and has a designed capacity of 3,668 m³/day, with an average discharge volume of 559.7 m³/day. It is situated in a rural area within 10 km of the coast, reflecting the region's mix of agricultural and residential inputs. As a secondary treatment plant, NARBERTH WES STW meets the minimum standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary treatment for populations between 2,000 and 10,000 in inland areas, and more stringent treatment may be required if the receiving waters are designated as sensitive. The plant's operational context aligns with typical UK regulatory practices, where permits are issued by Natural Resources Wales to control discharge quality and protect local water bodies. The treated effluent from NARBERTH WES STW ultimately drains into the Eastern Cleddau river catchment, which flows into Milford Haven Waterway and then into the Celtic Sea. This coastal estuary supports diverse aquatic life, including salmon and sea trout, and is an important ecological and economic resource for Pembrokeshire. The plant's proximity to the coast underscores the need for effective nutrient removal to prevent eutrophication in the sensitive marine environment.

The plant discharges into the Eastern Cleddau river system, which flows into the Milford Haven Waterway, a large ria estuary in Pembrokeshire. This waterway is ecologically sensitive, supporting diverse habitats including saltmarsh, mudflats, and seagrass beds, and is a key site for migratory birds and fish species. The estuary ultimately opens into the Celtic Sea, where nutrient inputs from inland sources can affect coastal water quality and marine ecosystems.