GAC and ion exchange resin disposal options include incineration or landfilling. However, the long-term viability of landfilling may change as research and regulations advance. Current research indicates that incinerating the media under controlled conditions and high temperatures destroys PFAS, which can help permanently remove PFAS from the environment.
GAC also has the option of being regenerated and reused. The regeneration process uses heat at a controlled high temperature to reactivate the carbon. Current research indicates that PFAS are destroyed during the regeneration process.
It is technologically possible to regenerate resin using steam to remove the PFAS. However, this method does not destroy the PFAS; the remaining concentrated PFAS solution will need a disposal solution, so this may not be practical for many water providers.
A design consideration is waste discharge. GAC and most of the available PFAS treatment resins will require flushing when first installed to remove fine particles that may be present in the media and to stratify the bed.
During the initial flushing procedures, when GAC is installed, GAC can release arsenic, which is naturally present in the carbon. Arsenic will be discharged with the waste and may go to the sewer or a waste holding tank, so waste disposal should be coordinated with the receiving entity. Pre-rinsed GAC is available, which can reduce initial flushing requirements and waste volumes.
Another issue is tolerance to chlorine. GAC can handle low chlorine levels, but ion exchange cannot. Keep this in mind with the current water source used for backwash.