The San Antonio Water System (SAWS) desalination project, a Zachry-led joint venture, transforms brackish water into millions of gallons of drinkable water. SAWS and the City of San Antonio (CoSA) worked together to find an alternative source of water for San Antonio. The solution was to drill deeper, going up to 1,720 feet for the production supply wells and over 5,000 feet deep for the disposal wells.

This project is Phase I of the solution which included a 60,000-square-foot water treatment plant facility located at the previous SAWS Twin Oaks Aquifer Storage and Recovery site (3,000 acres).  The facility is now called H2Oaks and produces up to 12 million gallons of treated water per day through a reverse osmosis process in which salts and minerals are removed or desalination. The treatment plant involved a complicated process of mechanical, electrical and supervisory control and data acquisition (SCADA) – basically the brains of the plant controls systems; some of this equipment required many months lead times for manufacturing.

The project also included drilling four production wells and one injection well, the fit out of 12 production and two injection well sites, and installing over 12 miles of high density polyethylene (HDPE) – a thick walled piping that is somewhat flexible and “fused” (welded) together at the joints, conveyance pipeline and access roads to the remote well sites.  Zachry also provided start-up, commissioning and acceptance testing.

SAWS now uses H2Oaks as a public tour destination, with bus parking lanes, large observation areas, a conference room and a laboratory for college-level research projects. Phases II and III are expected to produce an additional 12 and 6 MGD, respectively, bringing the total capacity to 30 MGD by 2026 — the largest in Texas and the largest inland desalination plant in the country.

Phases II and III are expected to produce an additional 12 and 6 MGD, respectively, bringing the program’s total capacity to 30 MGD by 2026 — the largest in Texas and the largest inland desalination plant in the country.