The city of Palm Coast, Florida, was experiencing elevated color in a concentrate stream typically directed to a lime-softening facility for recovery as drinking water. Water-quality efforts directed at meeting the lime plant’s secondary-color standards limited the concentrate volume able to be recovered.
In consultation, Palm Coast city staff and Sanford, Florida-headquartered CPH Engineers identified use of ozone as one good way to reduce color from the concentrate stream. Pilot-testing demonstrated that ozone could effectively address the color issues and improve concentrate quality to the lime plant. It would also be the lowest-cost alternative.
Having decided on the best course of action, both project-budgeting and -scheduling issues were significant challenges for the city in its efforts to receive grant funding.
Ozone-related innovation
As is well-known, ozone is an inorganic molecule with the chemical formula O3. It is a pale-blue gas with a distinctively pungent smell. Ozone is a powerful oxidant and has many industrial applications. Ozonation is the process of infusing water with ozone and is used to facilitate organic breakdown.
To start, several oxidative treatment processes were piloted in efforts to reduce concentrate color.
Based on pilot-testing results, the city chose the Summit Series system from Pinnacle Ozone Solutions, Cocoa, Florida. The ozone system chosen was selected based on its perceived ability to offer the greatest functionality and lowest total lifetime cost. It is able to match ozone production to real-time demand via automatic control of the ozone generator platform and three injection process trains using "on-demand" controls.
Onward to installation
Pinnacle Ozone Solutions worked with city staff and CPH engineers to implement a comprehensive ozone system. Pinnacle-provided pilot equipment and process-optimization services were used to validate the application’s parameters. An integrated design approach culminated in specification of an onsite oxygen generator, modular ozone generator, closed-loop chiller system, Venturi-based ozone-injection system and ozone-off gas-destruct system.
The ozone system was implemented in the fall of 2014. It reduces organic-based color of the low-pressure reverse-osmosis system concentrate stream. As significant, in an innovative and unique treatment application, this pre-treated concentrate stream is processed as an alternative water source at the city’s lime softening facility.
The process allows recovery and treatment of up to 750,000 gallons per day of alternative water supply that otherwise would have been discharged to waste. Dissolved color of the concentrate stream was reduced from 62 to less than 30 true-color units.
A unique aspect of the project is control of the ozone dose based on both dissolved-ozone and dissolved-color. Dissolved-ozone probes provide feedback to the controls for the ozone-injection process. However, the dissolved-color meter provides the final-compliance point and allows for automatic adjustment of the ozone dose. The integrated system automatically adapts and compensates for changes in the plant’s concentrate-water quality.
Final words
As mentioned, a significant project challenge was budget and schedule. To qualify for available Florida Department of Environmental Protection and St. Johns River Water Management District grant funding, the city needed to complete the entire ozone project in less than six months. Pinnacle Ozone Solutions manufactured and delivered all the ozone-process equipment within six weeks of receiving the purchase order.
Installation was completed working with the contractor Sawcross, Inc., of Jacksonville, Florida. At startup and testing, initial system results exceeded performance goals. Pinnacle delivered and substantially completed a fully integrated ozone system within the schedule needed to receive grant funding.
Contributors to this article included Brian Matthews, environmental specialist; Jim Hogen, utility systems manager; and Peter Roussell, utility systems chief operator – all of the city of Palm Coast, Florida; as well as Lucida Xu, senior engineer, CPH Engineers.
Pinnacle Ozone Solutions is headquartered in Cocoa, Florida, at the heart of Florida’s "Space Coast" high-technology corridor. Its work is devoted exclusively to ozone design, development, manufacture and testing.
