Cosio Sur Wastewater Treatment Plant, Cosio, Aguascalientes, Mexico

Cosio Sur is a municipal wastewater treatment plant located in Cosio, Aguascalientes, Mexico. The plant serves a small community of 3,222 residents, providing essential sanitation services for the local population. It is situated in the semi-arid highlands of central Mexico, an area characterized by seasonal rainfall and limited surface water resources. The plant employs secondary treatment, which typically involves biological processes to remove organic matter and suspended solids. With a designed capacity of 518.40 cubic meters per day and an actual discharge volume of 304.99 cubic meters per day, the plant operates below its full capacity. In Mexico, wastewater treatment plants are regulated under the National Water Law (Ley de Aguas Nacionales) and NOM-001-SEMARNAT-1996, which sets discharge limits for pollutants. The treated effluent from Cosio Sur is discharged into local water bodies that ultimately drain into the Rio Grande de Santiago basin, which flows westward to the Pacific Ocean. The plant plays a crucial role in protecting downstream water quality and supporting the ecological health of the region's intermittent rivers and reservoirs.

Cosio Sur discharges treated wastewater into local arroyos that feed into the Rio Grande de Santiago basin, which flows through the states of Aguascalientes and Jalisco before reaching the Pacific Ocean. The region's semi-arid climate means surface water flows are highly seasonal, making the plant's consistent treatment essential for maintaining water quality in downstream ecosystems. The receiving waters support agricultural irrigation and provide habitat for native aquatic species adapted to variable flow conditions.