El Naranjo Wastewater Treatment Plant, Colima, Mexico

El Naranjo wastewater treatment plant is located in the town of El Naranjo, within the municipality of Manzanillo, Colima, Mexico. The plant serves a population of approximately 2,556 people, making it a small-scale municipal facility. Its location near the Pacific coast places it in a region with significant tourism and ecological importance. The plant operates with secondary treatment, which is the standard level required under Mexican regulations (NOM-001-SEMARNAT-1996) for discharge into coastal waters. It has a designed capacity of 864.00 m³/day and currently treats 241.92 m³/day, indicating it is operating well below capacity. As a coastal plant, it must comply with stringent discharge standards to protect marine ecosystems. The treated effluent is discharged into the Pacific Ocean via local drainage, likely through the Cihuatlán River or nearby arroyos. The coastal waters of Colima support diverse marine life, including fish, crustaceans, and sea turtles. Proper treatment is critical to prevent nutrient pollution and protect the region's ecological health and tourism economy.

The plant discharges into the Pacific Ocean near Manzanillo, a major port city. The coastal waters are part of the Mexican Pacific ecosystem, which supports coral reefs, mangroves, and sea turtle nesting sites. Nutrient loading from untreated or poorly treated wastewater can lead to eutrophication and harm marine biodiversity. The plant's secondary treatment helps reduce organic matter and pathogens, but advanced treatment may be needed to fully protect sensitive coastal habitats.