Hialeah and Preston GWUDI Process Upgrades

Miami-Dade County, 

Hialeah and Preston GWUDI Process Upgrades

Service Type: 
Project Highlights: 
  • World’s largest NF facility design (165 mgd).
  • Flexibility to operate at recoveries up to 93 percent.
  • 3D design expedited review meetings and production of drawings
The world’s largest NF facility (165 mgd)
Carollo is designing the world’s largest NF facility (165 mgd), which will include the flexibility to operate at an aggressive 93-percent recovery.

The Miami-Dade County Water and Sewer Department (WASD) 225-mgd Hialeah and Preston Water Treatment Plants treat raw water from a combination of four groundwater wellfields, including the Northwest Wellfield (NWWF). Nearby mining activities may trigger the reclassification of the NWWF from groundwater to groundwater under the direct influence of surface water (GWUDI). This potential reclassification has significant implications for the plants by requiring the existing facilities to meet more stringent treatment standards than were originally intended. Portions of the existing softening treatment facilities date back from the mid-1920s to the most recent additions in the early 2000s. Initial analysis by Carollo found that constructing the required treatment upgrades at the NWWF reduced costs and community impacts as compared to constructing all the required upgrades within the existing Preston and Hialeah plant fence lines.

After analysis of treatment alternatives, WASD directed Carollo to design the world’s largest NF facility (165 mgd). Carollo tailored the design to meet all treatment requirements while controlling capital costs, retaining flexibility for future cost savings, limiting operator burden, and controlling O&M costs. Carollo used its 3D design capabilities to facilitate review meetings with WASD managers and regulators, while improving quality of drawing production.

The design includes flexibility to operate at recoveries between 85 and 93 percent. Validation testing supports effective system operation across this range. Benefits of enhanced recovery include:

  • Efficient use of limited source water.
  • Minimized life-cycle costs.
  • More economical than the development of alternative water supplies.

The results of Carollo’s design evaluations is a design that addresses WASD’s reliability requirements, while at the same time minimizing energy usage, optimizing water quality, and facilitating more robust operations and maintenance capability.