San Sebastian WWTP New - Municipal Wastewater Treatment in San Sebastián, Puerto Rico

San Sebastian WWTP New is a municipal wastewater treatment facility located in Sector Colón Madera, San Sebastián, Puerto Rico. It serves a population of approximately 6,529 residents in the western interior region of the island. The plant is part of Puerto Rico's wastewater infrastructure managed under the US Clean Water Act framework. As a small-scale facility serving fewer than 10,000 people, the plant is subject to secondary treatment standards under the US Clean Water Act and Puerto Rico's Environmental Quality Board (EQB) regulations. The designed capacity is 1.00 million gallons per day, indicating a facility sized for the local community's needs. Treatment processes typically include primary and secondary treatment stages to meet effluent limits. The plant discharges treated wastewater into local waterways that drain toward the Caribbean Sea. The region's tropical climate and karst topography influence water quality management. Downstream waters support diverse aquatic life and are important for local ecosystems and recreational uses. The facility plays a key role in protecting water resources in the Río Grande de Añasco watershed.

The plant discharges into the Río Grande de Añasco watershed, which flows westward to the Caribbean Sea near Añasco. This coastal zone supports mangrove forests, seagrass beds, and coral reef ecosystems. The watershed is ecologically sensitive due to its tropical biodiversity and the importance of maintaining water quality for marine habitats and local fisheries.