Seawater Desalination and PFAS
Seawater desalination is expanding globally to address freshwater scarcity. While reverse osmosis—the primary desalination technology—effectively removes PFAS from product water, PFAS concentrate in the reject brine poses environmental disposal challenges.
RO Performance for PFAS in Desalination
Seawater RO membranes achieve 95–99% PFAS rejection, producing product water with very low PFAS concentrations. Desalinated water from properly operated RO plants typically meets EPA PFAS MCLs without additional treatment steps.
Brine Concentrate Management
PFAS-concentrated brine disposal creates environmental concerns when concentrated reject water returns to coastal or inland environments. Brine concentrations of PFAS can be 5–20x source water levels, requiring environmental assessment before ocean or land disposal.
Inland Desalination and PFAS Challenges
Inland brackish water desalination plants face more complex brine disposal constraints than coastal facilities. Zero liquid discharge (ZLD) systems that evaporate brine concentrate PFAS in solid residuals, requiring landfill disposal with PFAS-containment capabilities.