Nogales IWWTP
The Nogales International Wastewater Treatment Plant, (NIWTP) is adjacent and westerly of the Santa Cruz River/Nogales Wash confluence, about ten miles north of Ambos, Nogales. It treats a daily average dry weather flow of approximately fourteen million gallons, of which seventy per cent is from Mexico. For thirteen years, it has employed oxygenated pond technology and industry – standard chlorination/dechlorination for effluent disinfection. It is expected that a $60 million upgrade, to be online by 2009, will use best available technology, in response to continuing stricter discharge permit requirements.

The project is staffed by eleven persons, including administrative support. Total yearly operation and maintenance cost is about $1.7 million of which 50 % is for electricity. Mexico, the City of Nogales, Arizona, and the U. S. Congress fund the project. In addition to responding to federal and state permits, the NIWTP provides river-based habitat for approximately ten downstream miles as well as replenishment of the aquifers serving Santa Cruz and Pima County communities.

Reports Concerning the NIWTP:

NIWTP Report on Pretreatment Activities for 2005

Nogales International Wastewater Treatment Plant (NIWTP) information brochure

Final Report of the Binational Nogales Wash United States/Mexico Groundwater Monitoring Program dated August 2001 in .pdf format

Joint Monitoring of the Quality of the Groundwater in the Ambos Nogales Area, Binational Nogales Wash United States/Mexico Groundwater Monitoring Program Interim Report of May 1998

Links to Other Field Offices