Chalchihuitán Wastewater Treatment Plant, Chiapas, Mexico

The Chalchihuitán wastewater treatment plant serves the community of Chalchihuitán in the state of Chiapas, Mexico. With a population served of 949, it is a small-scale facility designed to handle local domestic wastewater. The plant operates with secondary treatment, which is appropriate for its size and typical for small communities in the region. Under Mexican regulations (NOM-001-SEMARNAT-1996), secondary treatment is required for discharges into national waters. The plant's designed capacity is 277.34 m³/day, and it currently discharges 89.86 m³/day, indicating it is operating below capacity. This suggests room for future growth or seasonal variations in flow. The treated effluent is discharged into local water bodies that eventually drain into the Grijalva River basin, an important hydrological system in southern Mexico. The Grijalva River flows into the Gulf of Mexico, supporting diverse aquatic ecosystems and providing water for agriculture and communities downstream. The plant's secondary treatment helps reduce organic pollutants and protect these waters.

The plant discharges into the Grijalva River basin, which flows through Chiapas and into the Gulf of Mexico. This watershed supports a variety of aquatic life and is ecologically sensitive due to its tropical climate and biodiversity. Proper wastewater treatment is crucial to prevent nutrient loading and protect downstream habitats, including coastal zones.