Penrhyndeudraeth STW - Secondary Wastewater Treatment Plant in Gwynedd, Wales

Penrhyndeudraeth STW (Sewage Treatment Works) is a municipal wastewater facility located in Penrhyndeudraeth, Gwynedd, Wales, United Kingdom. The plant serves a population of approximately 2,198 and operates secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (UWWTD) for agglomerations of this size. The plant discharges an average of 489.35 cubic meters of treated effluent per day. As a secondary treatment plant, Penrhyndeudraeth STW removes organic matter and suspended solids through biological processes, meeting the effluent quality standards set by the UWWTD. The plant's designed capacity is 2,198 population equivalent, indicating it is sized to match the current served population. The facility is located within 10 km of the coast, making its discharge subject to additional environmental considerations under the UWWTD for sensitive coastal areas. The treated effluent from Penrhyndeudraeth STW ultimately reaches Cardigan Bay, part of the Irish Sea, which supports diverse marine life including bottlenose dolphins, seals, and important fish populations. The plant plays a key role in protecting the coastal water quality of this ecologically significant bay, which is designated as a Site of Special Scientific Interest (SSSI) and a Special Area of Conservation (SAC) for its reef and sandbank habitats.

Penrhyndeudraeth STW discharges treated wastewater into the local catchment that drains into Cardigan Bay, a large embayment of the Irish Sea. Cardigan Bay is ecologically sensitive, supporting important marine habitats such as reefs, sandbanks, and seagrass beds, and is home to protected species like bottlenose dolphins and harbor porpoises. The plant's secondary treatment helps reduce nutrient and organic loads, mitigating the risk of eutrophication and maintaining water quality in this coastal environment.