Background

COMAPA Río Bravo provides water and wastewater services to the entire municipality of Río Bravo. In the city of Nuevo Progreso, the wastewater collection system covers approximately 89% of the city’s population and collects about 19 liters per second (lps) or 433,665 gallons per day (gpd) of wastewater. In 2013 a regional, lagoon-based wastewater treatment plant (WWTP) was built in Rio Bravo, along with a lift station and force main to convey the wastewater collected in Nuevo Progreso to the plant.

In 2017, leaks began occurring along the entire length of the conveyance line because the pipe joints were failing, so the water utility stopped using the system. As result, the lift station was damaged by corrosion and later by vandalism. Currently, the wastewater collected in Nuevo Progreso is discharged to a drainage ditch that eventually flows into the Rio Grande River. The wastewater conveyance infrastructure serving Rio Bravo also failed, preventing the wastewater collected in Rio Bravo from reaching the regional WWTP. Without flows to the pond system, the growth of vegetation inside the lagoons and berms has made the facility inoperable.

To address these deficiencies, COMAPA Río Bravo developed a project to rehabilitate the wastewater conveyance infrastructure serving Nuevo Progreso, as well as one of the three treatment trains in the regional WWTP to provide sufficient capacity to treat the wastewater flows from that city. The wastewater collection and conveyance infrastructure serving Rio Bravo, along with the other two treatment trains of the WWTP will be rehabilitated through a separate project.

Description

The main project components include:

• Force main. Rehabilitation of approximately 10,800 meters (6.7 miles) of 12-inch polyvinyl chloride (PVC) pipe, including the replacement of air relief valves and the rehabilitation of concrete boxes.
• Lift Station. Rehabilitation of the lift station, including pumps, the electrical system, backup generator, and control room, as well as the the headworks to ensure an operational capacity of 25 lps (570,612 gpd).
• Regional WWTP. Rehabilitation of one treatment train, including the anaerobic, facultative and maturation lagoons, along with the headworks.

The CAP funds will be used for the rehabilitation of the force main and lift station. Funds from COMAPA Río Bravo will be used to rehabilitate the treatment train at the regional WWTP, which includes removing the vegetation inside the lagoons and recompacting the soil to obtain the required impermeability, along with improvements to the headworks.

Benefits

The project will eliminate untreated wastewater discharges and prevent the potential contamination of surface and groundwater, including the Rio Grande River, thus directly benefitting the entire population of Nuevo Progreso, as well as communities downstream on both sides of the border that depend on the river for drinking water. Specifically, the project will safely convey 19 lps (433,665 gpd) of wastewater to the regional WWTP for proper treatment.