Nogales IWWTP
The Nuevo Laredo International Wastewater Treatment Plant is an activated sludge—extended aeration—wastewater treatment plant located adjacent to the Rio Grande, 7 miles downstream of Nuevo Laredo, Tamaulipas, Mexico. The plant has a maximum design capacity of 31 million gallons per day (mgd) and is currently treating 20 to 22 mgd of domestic sewage from the City of Nuevo Laredo to the secondary level that would otherwise flow untreated directly into the Rio Grande. The project was undertaken pursuant to IBWC Minute No. 279 to improve the quality of the waters of the Rio Grande in the area of Laredo, Texas/Nuevo Laredo, Tamaulipas and was jointly financed by the United States and Mexican Governments.

The construction and operation and maintenance of this joint international sanitation project were undertaken under the supervision of the Commission and under the jurisdiction of the Mexican Section. Minute 279 also provided for the construction of sewage collector lines in Nuevo Laredo and construction of a lift station, with pumping capacity of 82 mgd.

Prior to construction of the plant, 70% of the population of Nuevo Laredo was connected to the Nuevo Laredo sewage collection system, which discharged an average of 20 to 25 mgd of untreated sewage to the Rio Grande from more than 28 location, creating a serious health hazard in the river for a distance of 41 miles downstream. Downstream of the Laredo, Texas/Nuevo Laredo, Tamaulipas urban area, large areas of lands in both the United States and Mexico were irrigated with water pumped directly from the river. Using contaminated water for crops presented a potentially serious health threat to the people consuming agricultural products irrigated with those waters. Also, the contaminated waters of the Rio Grande posed a serious health hazard to the communities of San Ignacio, Texas and San Ignacio, Tamaulipas, located 40 miles downstream of Laredo, Texas/Nuevo Laredo, Tamaulipas, which obtained their drinking water from the river. During periods when the Falcon International Storage Reservoir was not generating high river flows, the pollution generated in the Laredo, Texas/Nuevo Laredo Tamaulipas area also posed a threat to the municipal water systems at Zapata, Texas and Nuevo Ciudad Guerrero Tamaulipas.

Construction took place from March 1992 to December 1994, but was suspended for a year due to the devaluation of the peso. Construction resumed in August 1995 and was substantially completed in April 1996. The plant was dedicated and began operations on April 17, 1996, pending completion of the waste sludge drying beds. This final phase of construction was begun in 1998 and completed in January 2000. The final cost of the treatment plant and associated pump station was close to $60 million.

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