Key distinction: treatment can produce clean water while transferring PFAS into spent media, brine or concentrate. The residual stream still needs appropriate management.
Granular activated carbon (GAC)
Activated carbon removes PFAS by adsorption. EPA describes GAC as the most studied treatment option for PFAS removal. Performance depends on PFAS chemistry, carbon type, bed depth, flow rate, temperature and competing organic matter. Longer-chain compounds have historically been easier to adsorb than some shorter-chain PFAS.
Commercial considerations
- Media replacement frequency and breakthrough curves.
- Pre-treatment and competing contaminants.
- Handling, regeneration or disposal of spent carbon.
- Full-scale versus point-of-use configuration.
Ion exchange (IX)
Anion exchange resins use positively charged sites to attract negatively charged PFAS species. EPA notes that these resins can have high capacity for many PFAS. Single-use and regenerable configurations have different residual-waste implications.
Reverse osmosis & nanofiltration
High-pressure membrane technologies can remove a broad range of PFAS, including shorter-chain compounds. Their principal trade-off is the creation of a concentrated reject stream, so the full treatment train must account for concentrate management.
Technology selection
No single technology is best for every site. Selection depends on influent concentrations, target PFAS, flow, co-contaminants, footprint, residuals strategy, local requirements and lifecycle cost.