Piscila II Wastewater Treatment Plant, Piscila, Colima, Mexico

Piscila II is a municipal wastewater treatment plant located in the town of Piscila, within the municipality of Colima, in the state of Colima, Mexico. The plant serves a small population of 274 residents, providing secondary treatment for domestic wastewater. It is situated inland, more than 50 km from the coast, and operates as part of the local water infrastructure. As a secondary treatment facility, Piscila II employs biological processes to reduce organic matter and suspended solids. The plant has a designed capacity of 345.60 m³/day, with an actual discharge volume of 25.92 m³/day, indicating it operates well below its 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. Plants of this scale are typically required to meet secondary treatment standards to protect receiving waters. The treated effluent from Piscila II is discharged into local water bodies that eventually drain into the Pacific Ocean via the Armería River basin. The region's hydrology supports agricultural and ecological systems, and proper treatment helps maintain water quality in downstream environments. The plant contributes to reducing pollution loads in the Colima region, supporting both public health and environmental sustainability.

Piscila II discharges treated wastewater into local streams that flow into the Armería River, which ultimately reaches the Pacific Ocean. The Armería River basin supports diverse aquatic life and provides water for irrigation in the region. Proper secondary treatment helps protect downstream ecosystems from nutrient enrichment and organic pollution, maintaining the ecological balance of the river and coastal waters.