Casalito Wastewater Treatment Plant, Óbidos, Portugal

Casalito is a former wastewater treatment plant located in Óbidos, a town in the Leiria district of Portugal. The plant served a population of approximately 9,000 people and was designed with a capacity of 1.00 cubic meters per day. It is now closed and no longer operational. As a Portuguese wastewater facility, Casalito would have operated under the national regulations transposing the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this size (9,000 population equivalent), the directive requires secondary treatment or equivalent. The plant is situated near the Atlantic coast, within 50 km of the ocean. Its discharge likely affected local water bodies draining into the Atlantic. The region's watershed includes small streams and the Óbidos Lagoon, a coastal lagoon of ecological importance. The closure of the plant may have led to wastewater being redirected to other facilities in the area.

Casalito is located near the Atlantic coast of Portugal, within the watershed of the Óbidos Lagoon, a coastal lagoon that supports diverse aquatic life and migratory birds. The lagoon connects to the Atlantic Ocean via a narrow channel. The plant's discharge, when operational, would have influenced the lagoon's water quality and the downstream marine environment. The region's coastal ecosystems are sensitive to nutrient inputs and require careful management.