SAN LUIS, AZ (AZFamily) — Construction is slated to begin this fall on a massive expansion of the San Luis Wastewater Treatment Plant, a high-priority infrastructure project designed to more than triple the facility’s daily capacity as this rapidly growing border community continues to expand.
The project, scheduled to begin in October and finish by 2028, will increase the plant’s treatment capacity from 1.1 million gallons per day to 3.5 million gallons per day.
City officials say the expansion is critical to keep pace with a surging population and rising commercial interest.
“We are at 95 percent capacity at our plant,” said Eulogio Vera, the public works director for the City of San Luis. “With this expansion, we will be able to accept a lot more growth... residential, commercial, and industrial.”
Currently, the city’s wastewater is treated using a sequential batch reactor system. The upcoming expansion will transition the facility to an advanced Membrane Bioreactor (MBR) system, fundamentally changing how the city processes its wastewater. MBR technology integrates microfiltration or ultrafiltration membranes directly into the biological treatment process, producing extremely clean, high-quality recycled water.
This technological leap comes as municipalities across Arizona face mounting pressure to recharge, recycle, and reuse wastewater amid worsening regional water scarcity and rising costs of fresh water.
“This actually produces high-quality water that can be used for irrigating parks or irrigating some of the ag fields as well,” Vera said. “So I guess in return, you’re actually using a lot less groundwater or surface water.”
Currently, treated wastewater from San Luis is discharged into the Mode Canal and sent south to Mexico, where it eventually absorbs into the ground.
While the new plant expansion will lay the physical piping necessary to recycle and route reclaimed water to local parks, landscaping, and industrial complexes, residents will not see that reuse immediately.
City officials noted that San Luis is still finalizing the broader infrastructure and distribution plans required to fully implement the water recycling program.
My Thoughts 💭
San Luis getting ahead of the waste waster demand for their little town. Using MBR Technology (👀@k00b) is a wise choice for gray water reuse. Hopefully the public works department have the staff to complete the O&M and say in compliance with discharge requirements.