PFAS is the new emerging pollutant of concern. It is the big bad in industrial waste. Nearly every session at NEWEA 2020 addressed the topic, and it was the leading buzzword from the event. The EPA has given PFAS its own page.

PFAS – Per- and Polyfluoroalkyl Substances (PFAS) – gets a lot of attention for several reasons:

1. It still isn’t clear what a ‘safe’ level is.
2. Testing for it is difficult.
3. It’s man made.
4. It appears to be nearly everywhere.
5. It appears to be conserved at each step where other materials would be destroyed or reduced.

Dr. Linda Lee of Purdue University appeared on WEFTEC’s “Words on Water” podcast, and her review covered how PFAS is affected by most modern water treatment technologies.

Water Treatment and Filtration Processes and their Impact on PFAS

Advanced Oxygen Processes (AOPs) – have no effect.

Membrane Processes – can obstruct the PFAS, but then serve to concentrate the PFAS in the retentate. The resulting biosolids are then full of PFAS.

Reverse Osmosis – RO, like other membrane processes, can create PFAS-free water for drinking. However, the retentate then has concentrated PFAS.

Carbon Bed – carbon can capture the PFAS, but the PFAS remains caught in the carbon. The carbon can be incinerated, but care must be taken to ensure that the PFAS are destroyed.