The City of Tampa is preparing to introduce an innovative approach to drinking water treatment with the nation’s first Suspended Ion Exchange (SIX®) system. Once completed, the facility will be the largest of its kind in the world, capable of treating up to 140 million gallons of water per day.
A recent article from the American Society of Civil Engineers (ASCE), titled “Revolutionary Water Treatment System Could Be Transformational for Tampa,” explores how Carollo Engineers helped evaluate this technology and why it could reshape water treatment in Tampa and beyond.
Addressing Tampa’s Changing Water Quality
Tampa relies on the Hillsborough River for its drinking water, but the river’s water quality changes dramatically throughout the year.
“There’s two distinct seasons with respect to the water quality in the river,” explained Melanie Pickett, a Carollo senior engineer who oversaw the project’s pilot study. “The total organic levels go from about 3.5 milligrams per liter in the winter, and then it’ll suddenly jump to about 30 milligrams per liter in the spring.”
These fluctuations require frequent adjustments to conventional treatment processes. Developed by PWNT, SIX® offers a more adaptable approach by removing organic matter early in the treatment process, improving the performance of downstream treatment systems.
Putting Suspended Ion Exchange to the Test
Before moving forward with the full-scale system, a 10-month pilot study evaluated how SIX® technology would perform with Tampa’s source water.
“We saw that (it) worked well right out of the gate,” Pickett said.
The results demonstrated significant improvements across multiple treatment processes. Coagulant demand dropped by approximately 70%, while ozone requirements decreased by roughly 30%. The system also reduced solids production, improved filtration performance, and demonstrated some PFAS removal.
These findings showed how SIX® could improve water treatment efficiency while reducing chemical use and operational costs.
Moving Toward Full-Scale Implementation
Following the successful pilot study and an independent third-party review, Tampa moved forward with a detailed design for the new system at its David L. Tippin Water Treatment Facility.
The project represents an estimated $220 million investment, with projected annual chemical savings of approximately $2 million.
“It’s been very rare in my career where there’s something that made so much sense,” said Carollo Executive Vice President Vinnie Hart. “It’s a great fit for Tampa.”
Advancing the Future of Drinking Water Treatment
With a proven track record in Europe and promising results from Tampa’s pilot study, SIX® offers new opportunities for utilities managing variable source water quality and evolving treatment demands.
To learn more about the pilot study, its findings, and how Tampa is bringing this technology to the United States, read the full article from the American Society of Civil Engineers.
