Conventional drinking water treatment technologies (coagulation, flocculation, clarification, filtration, and disinfection) have not been found to be effective in removing PFAS. Technologies have been found to remove longer-chain PFAS, such as PFOA and PFOS, from drinking water including activated carbon adsorption, ion exchange resins, and high-pressure membranes. These technologies can be used in drinking water treatment facilities, in point-of-entry systems to treat all the potable water that enters a home or other building, or at the point-of-use of potable water, such as in a kitchen sink. Effective technologies generally fall into three categories:
1) Granular Activated Carbon (GAC)
✔ Best for long-chain PFAS (PFOA, PFOS)
✔ Widely used in water treatment plants
✔ Relatively cost-effective
How it works: PFAS molecules “stick” to the surface of the carbon.
Challenges:
- Short-chain PFAS breakthrough faster
- Carbon must be replaced or regenerated
- Competes with other organic contaminants
2) Ion Exchange Resins (IX)
✔ Highly effective for both long- and some short-chain PFAS
✔ Fast and efficient
✔ Often used with GAC in hybrid systems
Challenges:
- Resins are expensive
- Regeneration produces concentrated brines
- Requires careful waste handling
3) Reverse Osmosis (RO)
✔ Most effective PFAS removal technology for households
✔ Removes nearly all PFAS compounds
Challenges:
- Produces a waste concentrate
- High energy cost for large systems
- Requires pre-treatment to avoid membrane fouling
RO is commonly used in under-sink household filtration systems.