Drainage and sanitation measures in the town of Nogales, Sonora

1.- Rehabilitation of the Los Alisos gravity sewer main: rehabilitation of approximately 10 km to improve wastewater conveyance to the Los Alisos Wastewater Treatment Plant (WWTP).
2.- Puerta de Anza WWTP – Phase 1: rehabilitation and capacity expansion from 45 to 110 L/s to meet current demand in the eastern sector of Nogales.
3.- Lomas de Anza WWTP: rehabilitation and capacity expansion from 30 to 50 L/s to increase treatment capacity.
4.- Los Alisos WWTP: expansion of treatment capacity from 330 to 440 L/s through the construction of a fourth module.
5.- International Arroyo culvert enclosure: structural rehabilitation of a 200-meter section, including repairs to cracks, fissures, and the conduit’s invert and top slab.
6.- Relocation of sewer infrastructure: relocation of the San Carlos sub-collector and the Ruiz Cortines collector, including piping and manholes.
7.- Estadio Station lift station: rehabilitation of the lift station, replacement of five pumping units, and modifications to control flow to the Río Rico WWTP.
8.- El Oso Arroyo: construction of a local treatment system to address untreated wastewater discharges.
9.- Central sector sewer network: rehabilitation of sanitary infrastructure to improve performance and prevent service disruptions.
10.- Construction supervision: contracting of supervision services to ensure the proper development and execution of the works.
11.- Increased pumping to Los Alisos WWTP: increase from 220 to 330 L/s through the repair of two pumping units, prior to the comprehensive rehabilitation of the lift station.
12.- Maintenance of regulating dams: preservation and maintenance of gabion structures for sediment retention and protection of sanitary infrastructure. 13.- New gabion dam: construction of an additional dam to retain sediment and protect infrastructure.
14.- Water quality monitoring: implementation of an ongoing sampling and analysis program to detect heavy metals from industrial sources.
15.- Industrial discharge monitoring: installation of pH and electrical conductivity sensors, as well as automatic samplers, at identified industrial facilities.
16.- Puerta de Anza Wastewater Treatment Plant – Phase 2: capacity expansion from 110 to 200 L/s to meet future demand and ensure the required treatment capacity through 2050.

In total, the portfolio comprises 16 actions and projects—with an estimated investment of MXN 820 million—aimed at increasing treatment capacity, rehabilitating and protecting drainage and sanitation infrastructure, reducing infiltration and untreated discharges, and improving water quality monitoring in Nogales, Sonora.