Hilton Head Reverse Osmosis Water Treatment Plant Expansion

Ardurra provided design, permitting, and funding assistance to expand the Hilton Head Public Service District's reverse osmosis water treatment plant from 4.0 MGD to 6.0 MGD. The district serves 25,500 full-time residents and more than 2.5 million annual visitors on Hilton Head Island. Saltwater intrusion led to the abandonment of seven Upper Floridian Aquifer wells, and hydrogeologic modeling predicted the eventual loss of all UFA supply, creating an urgent need for expanded treatment capacity and system resilience. The design included two new membrane treatment units, a sodium hypochlorite disinfection system, an emergency generator and switchgear, and SCADA system upgrades. The team also designed a new RO supply well, ASR well, and associated transmission mains. Ardurra assisted HHPSD with securing SCIIP funding by preparing a competitive application, coordinating regional collaboration, and providing grant administration services.

Key Highlights:

• Increased RO treatment capacity from 4.0 MGD to 6.0 MGD with two new membrane treatment units to ensure long-term water supply reliability
• Designed new RO supply and ASR wells with transmission mains to mitigate saltwater intrusion impacts and protect against loss of aquifer supply
• Secured SCIIP funding through strategic grant preparation and administration, reducing financial burden on the district

The project protected the water supply for Hilton Head Island's residents and tourism economy by addressing saltwater intrusion and expanding treatment capacity to meet growing demand, while leveraging external funding to minimize local costs.