LLANFAIRFECN STW - Secondary Wastewater Treatment in Abergwyngregyn, Wales

LLANFAIRFECN STW (Sewage Treatment Works) serves the community of Abergwyngregyn in Gwynedd, Wales, United Kingdom. The plant provides secondary treatment for a population equivalent of 3,770, with a designed capacity of 3,783 m³/day and an average daily discharge of 839.33 m³/day. As a secondary treatment facility, the plant meets the minimum treatment standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive mandates secondary biological treatment for populations between 2,000 and 10,000 in inland and coastal areas, which this plant fulfills. The plant discharges treated effluent into local watercourses that drain into the Irish Sea. Its proximity to the coast (within 10 km) means the discharge may affect sensitive coastal ecosystems, including estuaries and marine habitats that support diverse aquatic life and migratory bird populations.

The plant discharges into small streams that flow into the Menai Strait and eventually the Irish Sea. This coastal region supports important habitats for seabirds, fish, and marine mammals. The secondary treatment level helps reduce organic pollution and protect the sensitive coastal environment from nutrient enrichment and pathogen contamination.