S Martinho do Porto Wastewater Treatment Plant, Caldas da Rainha, Portugal

S Martinho do Porto is a wastewater treatment plant located in Caldas da Rainha, Leiria District, Portugal. It serves a population of approximately 24,300 people, classifying it as a medium-sized agglomeration under EU standards. The plant is situated near the coastal area of S Martinho do Porto, a bay on the Atlantic Ocean. As a Portuguese facility, the plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size discharging into coastal waters. The plant's coastal location means it must meet stringent discharge standards to protect marine water quality. The treated effluent is discharged into the Atlantic Ocean via the S Martinho do Porto bay, which is part of the larger coastal ecosystem. This area supports diverse marine life and is important for local fisheries and tourism. The plant plays a key role in preventing nutrient pollution and safeguarding the ecological health of the bay and adjacent coastal waters.

The plant discharges into the Atlantic Ocean at S Martinho do Porto bay, a coastal inlet in the Leiria region. The bay is part of a dynamic marine ecosystem that supports fish, shellfish, and migratory bird populations. As a coastal discharge point, the plant must comply with EU standards for sensitive areas to prevent eutrophication and protect bathing water quality, which is vital for local tourism and recreation.