Hermosillo, Sonora, Mexico

Wastewater Treatment Plant for the City of Hermosillo, Sonora

Status: Completed


Currently, Hermosillo provides drinking water to approximately 98 percent of residents and sewage collection services to 97 percent; however, wastewater treatment is estimated at only 11%. Untreated sewage is discharged into streams west of the city, which eventually flow into the Sonora River. A portion of the raw sewage is also used for agricultural purposes in the Villa de Seris-La Yesca and La Manga irrigation areas.

The City of Hermosillo and the local water utility propose to increase wastewater coverage to 100% of the population through the construction of new wastewater treatment plant. In 2010, local water utility conducted a competitive bid process for the design, construction,
operation and transfer of the wastewater treatment infrastructure and awarded the service contract to a consortium of firms that has created a special-purpose enterprise called TIAR Hermosillo, S.A.P.I. de C.V. to carry out the project.


The project consists of the following components:

Hermosillo Wastewater Treatment Plant
Construction of a plant with the capacity to treat 2,500 liters per second (lps) or 57 million gallons a day (mgd) of wastewater. The effluent quality will meet the parameters established in Mexican standard NOM003-SEMARNAT-1997, for reuse in services in direct contact with the public. The plant includes pre-treatment works and sludge treatment, as well as the construction of two pump stations.

Extension of the Collector Main
Construction of 1.43 miles of 96-inch gravity pipeline to connect the collector system to the plant.


This project will reduce environmental and health hazards associated with untreated wastewater discharges, thus providing a cleaner healthier environment for local residents. Specifically, an estimated 45.6 mgd (2,000 lps) of wastewater will be treated prior to being discharged into the environment.

Project Financing

Total Project Cost US 82.69M
NADBank Funding US 31.58M - NADBank Loan
Other Funding Partners FONADIN