EPA is issuing a notice of proposed action under the Clean Water Act. EPA is proposing to issue a National Pollutant Discharge Elimination System (NPDES) permit (No. NN0022195) to Navajo Tribal Utility Authority for the Ganado wastewater treatment facility, located approximately 0.5 mile south of US 264 in Ganado, Apache County, Arizona, in the Navajo Nation.
The Ganado treatment facility serves a population of 2,870 and receives only domestic wastewater with a design flow rate of 0.4 million gallons per day (“MGD”). Treatment consists of a two-lagoon gravity flow evaporation system with aeration, polishing and evaporation, and disinfection by chlorination prior to discharge. The proposed permit will regulate the discharge of treated effluent from the lagoon treatment facility to the Pueblo Colorado Wash, a tributary to Cottonwood Wash, an eventual tributary to the Little Colorado River. Outfall 001 is located at latitude 35o 42’ 33” North, longitude 109o 33’ 57.5” West in Apache County, Arizona.