El Cid II Wastewater Treatment Plant, Mazatlán, Sinaloa, Mexico

El Cid II is a wastewater treatment plant located in the Benito Juárez area of Mazatlán, Sinaloa, Mexico. It serves a population of approximately 36,509 residents, placing it in the medium-sized agglomeration category for Mexican wastewater infrastructure. The plant is situated near the Pacific coast, within 50 km of the ocean. As a Mexican wastewater facility, El Cid II operates under the national regulatory framework established by the Comisión Nacional del Agua (CONAGUA) and the Ley de Aguas Nacionales. For agglomerations of this scale, Mexican regulations typically require secondary treatment to meet discharge standards. It is expected to comply with applicable environmental norms. The plant's treated effluent ultimately drains into the Pacific Ocean via local waterways in the Mazatlán area. The coastal environment supports diverse marine life, including important fisheries and migratory species. Proper wastewater treatment is critical to protect water quality in the region's beaches and estuaries, which are vital for tourism and local ecosystems.

El Cid II discharges into the Pacific Ocean near Mazatlán, a coastal city in Sinaloa. The receiving waters are part of the Gulf of California ecosystem, which supports rich biodiversity including marine mammals, sea turtles, and commercially important fish species. The plant's proximity to the coast means treated effluent must meet strict standards to prevent nutrient enrichment and pathogen contamination in nearshore waters, which are used for recreation and fishing.