Binacional o Pitar Wastewater Treatment Plant, Tijuana, Baja California

Binacional o Pitar is a municipal wastewater treatment plant serving the city of Tijuana in Baja California, Mexico. With a population served of approximately 155,000, it is classified as a large agglomeration under Mexican water management standards. The plant is situated in the Zona Río district, near the Tijuana River, and lies within 50 km of the Pacific coast. Under Mexican regulations (NOM-001-SEMARNAT-2021), wastewater treatment plants serving populations over 100,000 are required to achieve secondary treatment and meet specific pollutant discharge limits. Facilities of this scale typically employ secondary biological processes such as activated sludge or aerated lagoons to comply with national standards. The treated effluent from Binacional o Pitar is discharged into the Tijuana River, which flows northwest into the United States and ultimately empties into the Pacific Ocean near the Tijuana Estuary. This estuary is an ecologically sensitive area that supports diverse bird species and serves as a critical stopover along the Pacific Flyway. The plant's operations are subject to binational oversight due to transboundary water quality concerns between Mexico and the United States.

The Tijuana River watershed drains into the Pacific Ocean via the Tijuana Estuary, a coastal wetland that provides habitat for migratory birds and endangered species. The estuary is affected by urban runoff and treated wastewater discharges from both Mexico and the United States. Binacional o Pitar's effluent contributes to the river's flow, which is closely monitored under the International Boundary and Water Commission agreements to protect downstream ecosystems and recreational waters.