Janitzio Wastewater Treatment Plant, Pátzcuaro, Michoacán, Mexico

Janitzio is a wastewater treatment plant located in Pátzcuaro, within the municipality of Tzintzuntzan, Michoacán, Mexico. It serves a population of 6,389 people, classifying it as a small-scale facility. The plant is situated near Lake Pátzcuaro, a culturally and ecologically significant water body in central Mexico. The plant provides secondary treatment, which is the standard biological treatment process for removing organic matter and suspended solids. With a designed capacity of 604.80 cubic meters per day and a discharge volume matching that figure, the plant operates at full capacity. Under Mexican regulations (NOM-001-SEMARNAT-1996), secondary treatment is required for discharges into inland water bodies to meet water quality standards. Treated effluent from the plant likely discharges into the Lake Pátzcuaro basin, a closed basin that drains into the lake itself. Lake Pátzcuaro is an important ecosystem supporting endemic fish species and migratory birds. The plant's operation helps protect the lake from untreated sewage, preserving its ecological integrity and supporting local communities that depend on fishing and tourism.

The plant discharges into the Lake Pátzcuaro watershed, a closed basin in the Trans-Mexican Volcanic Belt. The lake is a vital freshwater resource for the region, supporting diverse aquatic life including the endemic Pátzcuaro salamander and multiple fish species. Downstream, the basin has no outlet to the sea, making the lake sensitive to nutrient loading and pollution. The plant's secondary treatment helps reduce organic and nutrient loads, mitigating eutrophication risks in this ecologically sensitive lake.