Carrapatas Wastewater Treatment Plant, Macedo de Cavaleiros, Portugal

Carrapatas is a wastewater treatment plant located in the Linha do Tua area of Macedo de Cavaleiros, in the Bragança district of northern Portugal. The plant serves a population of approximately 3,800 residents and operates with secondary treatment, which is the standard level required under the EU Urban Waste Water Treatment Directive for agglomerations of this size. The plant has a designed capacity of 3,834 m³/day and currently discharges 633.58 m³/day of treated wastewater. As a secondary treatment facility, Carrapatas removes organic matter and suspended solids through biological processes, meeting the effluent quality standards set by Portuguese regulations. The plant is part of Portugal's compliance with the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment for inland discharges from agglomerations with a population equivalent above 2,000. The plant's capacity utilization is low relative to its design, indicating room for future growth or seasonal variations. The treated effluent from Carrapatas is discharged into the Tua River basin, a tributary of the Douro River. The Douro River flows westward through Portugal and empties into the Atlantic Ocean near Porto. The Tua River is an ecologically sensitive watercourse that supports diverse aquatic life, including native fish species. The plant's operation helps protect the water quality of the Tua and Douro rivers, which are important for regional biodiversity and downstream uses such as agriculture and recreation.

Carrapatas discharges into the Tua River, a tributary of the Douro River, which flows into the Atlantic Ocean near Porto. The Tua River basin supports diverse aquatic ecosystems, including native fish populations and riparian habitats. The plant's secondary treatment reduces organic pollution and protects downstream water quality in the Douro estuary, a region important for migratory birds and fisheries.