Chilean Comptroller finds unauthorized wastewater plants in Metropolitan Region

The Comptroller General of the Republic (Contraloría General de la República) has identified five municipal wastewater treatment plants operating without sanitary authorization in Chile's Metropolitan Region. The findings specifically involve the communes of María Pinto, Isla de Maipo, and Melipilla.

In María Pinto, three facilities—La Colonia, San Enrique, and Chorombo Bajo—were found to be operating without permission from the Seremi de Salud Metropolitana and in violation of Law No. 20,998. Audits revealed that these plants frequently exceeded permitted limits for biological oxygen demand (DBO5), fecal coliforms, total suspended solids, and pentachlorophenol.

Environmental concerns are heightened as these discharges affect the Estero Puangue, a watercourse used downstream for the irrigation of agricultural products intended for human and animal consumption. Previous municipal reports had already warned of pathogenic microorganisms in the water. The investigation also noted deficiencies in facility maintenance, a lack of periodic monitoring programs, and failures in coordination and oversight between public agencies.