The Challenge

The City of Sarasota, FL needed to retrofit its sole water plant from the existing hollow fiber membrane reverse osmosis system to a spiral wound system when the original system manufacturer decided to eliminate the production of hollow fiber membrane technology. 然而, the City needed to keep the plant in compliance with the Florida Department of Environmental Protection and the Florida Department of Health regulations, in both the quality and quantity of production, throughout the retrofit. The City decided to utilize the 设计/Build procurement process to ensure a creative, dependable team and to shorten the overall design and construction period. After careful evaluation and interviews, it selected Cardinal and Harn as the most responsible and responsive bidder.

The Solution

Harn R/O Systems proposed an innovative, yet radical solution: Build and operate the first 1.5 MGD train in the plant’s parking lot for a year while the two other existing hollow fiber trains were retrofitted, then dismantle, clean up and reinstall the “parking lot train” inside the building. Thus, virtually no materials or equipment were wasted, saving the owner time and money. The third train currently is indistinguishable from the two new trains installed initially. In addition, Harn worked closely with the general contractor and the control systems contractor to not only keep the plant at full capacity in both quantity and quality but to ensure a completely integrated system that enabled the City to save significantly in ongoing maintenance, energy and capacity costs.

The Result

Not only was the City’s expectations of the team met, but the project was completed on time and on budget, with the only change orders coming from the Owner to provide additional scope items.

“We’ve decreased power consumption by 25% due directly to the new system,” said Javier Vargas of the City of Sarasota. “We lowered the pressure from 400 pounds per square inch to 180 psi while decreasing the motors from 450 hp to 200 hp. We’ve gained 30% higher quality and, as a result, don’t need to run all three trains simultaneously. The Distributed Control System allows us to control and monitor the entire plant and delivers redundancy throughout the entire system, including other plants. We can take any flow meter, pressure gauge or other component offline for maintenance without adversely affecting the system. “We couldn’t be more satisfied,” he concluded. “Any issue that arose, Harn and the other team members solved. You can’t ask for anything more, especially when you’re dealing with a project of this complexity.”

Related Products

  • Reverse Osmosis System 设计/Build

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Brief R/O System Summary

City of Sarasota, FL

设计 Build Lead
Cardinal Contractors

Owner’s engineer: Boyle Engineering Corp. 设计/Build engineer: Hartman & Associates

Potable drinking water

September 2003

4.5 MGD

28:14, 6-element vessels, 3 trains

Hydranautics CPA3/ESPA2

Operating Data:
Feedwater TDS: 2,200 mg/l Permeate TDS: 80 mg/l R/O Feed Pressure: 150psi Recovery: 70%

System Features:

  • R/O skids custom designed to fit in tight, existing process area and for constructability while keeping other processes operational
  • New plant-wide distributed control system is user friendly and easy to upgrade
  • Piping designed to allow future addition of interstage boost pumps should raw water quality decline