Goje Wastewater Treatment Plant, Penalva do Castelo, Portugal

The Goje wastewater treatment plant is located in Sangemil, Ínsua, within the municipality of Penalva do Castelo in the Viseu district of Portugal. This facility serves a population of approximately 3,500 people, placing it in the small agglomeration category under Portuguese and EU regulations. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for sensitive areas. With a designed capacity of 4,000 m³/day and an average daily discharge of 583.56 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that eventually drain into the Dão River, a tributary of the Mondego River, which flows into the Atlantic Ocean near Figueira da Foz. The advanced treatment ensures minimal environmental impact on the receiving waters, supporting aquatic life and downstream water quality.

The plant discharges into small streams that feed the Dão River, part of the Mondego River basin. The Mondego is one of Portugal's major rivers, flowing through agricultural and urban areas before reaching the Atlantic. Advanced treatment helps protect the river's ecological health, supporting fish populations and biodiversity in the lower Mondego estuary.