City of Stuart PFAS Water Treatment System
The City of Stuart’s water treatment plant is a 6.0-MGD lime softening facility that needed an advanced treatment system to remove PFAS substances due to groundwater contamination from a nearby public safety complex. Kimley-Horn was called on to investigate the contamination and as a result, developed the first ion exchange (IX) water treatment system in Florida and the largest PFAS contamination removal system in the United States.
The neighboring facility was storing aqueous film-forming foams (AFFF)—firefighting foams—that were found to be the primary source of the groundwater contamination. This discovery forced the city to shut down some supply wells and construct an advanced treatment system to remove the PFOA, PFOS, and PFAS contaminants.
Emerging contaminants, including perfluorinated substances (PFAS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) were detected in the raw water supply from the city’s drinking water wells. Due to widespread contamination throughout the city’s wellfield, Kimley-Horn developed a water treatment system using ion exchange (IX) resin and granular activated carbon (GAC) toppings to treat the city’s entire raw water supply.
The new water treatment system can treat the entire raw water supply and act as a remediation system for the nearby public safety complex contamination site. At the time of completion, this innovative and alternative water treatment system had the distinction of being the first IX project of its kind permitted and constructed in Florida and the largest (up to 8.0-MGD treatment capacity) in the United States installed and placed into operation.
Kimley-Horn provided the design and permitting for this project, which involved four different resin manufactures (anion exchange) and can be converted to hold granular activated carbon (GAC). The team also assisted in the preparation of bid documents and construction phase services for the project. The new water treatment system removes PFAS and other emerging contaminants to less than 10 parts per trillion (non-detect level).
The City of Stuart Water Treatment project is an example of how an engineering consultant can successfully navigate the world of emerging contaminants while balancing sustainability and environmental stewardship. Kimley-Horn’s water treatment specialists creatively evaluated the PFAS removal technology and used their diverse water resource expertise to provide innovative solutions beyond a traditional water treatment engineering scope.