What are effective strategies to remove PFAS from drinking water?

2 Ion exchange

Ion exchange is a process that uses resin beads to exchange ions with dissolved contaminants, such as PFAS, in water. The resin beads have functional groups that can selectively bind to PFAS molecules and remove them from the water stream. Ion exchange can be used as a standalone or complementary technology to activated carbon, depending on the water quality and the PFAS composition. The main advantages of ion exchange are its high capacity, selectivity, and regeneration potential for PFAS removal. However, ion exchange also has some challenges, such as the high cost, the need for pre-treatment and post-treatment, and the disposal of spent resin and brine.

3 Membrane filtration

Membrane filtration is a technique that uses thin layers of material to separate contaminants, such as PFAS, from water by applying pressure or electric potential. The membrane acts as a physical barrier that blocks or rejects the contaminants based on their size, charge, or affinity. Membrane filtration can be classified into different types, such as reverse osmosis, nanofiltration, ultrafiltration, or electrodialysis. The main advantages of membrane filtration are its high rejection rate, low maintenance, and modular design for PFAS removal. However, membrane filtration also has some limitations, such as the high energy requirement, the risk of fouling and scaling, and the generation of concentrated waste streams.

4 Advanced oxidation

Advanced oxidation is a process that uses strong oxidants, such as ozone, hydrogen peroxide, or ultraviolet light, to degrade organic contaminants, such as PFAS, in water. The oxidants produce highly reactive radicals that can break down the carbon-fluorine bonds in PFAS molecules and form harmless byproducts. Advanced oxidation can be used as a final polishing step or in combination with other technologies, such as activated carbon or membrane filtration, to enhance PFAS removal. The main advantages of advanced oxidation are its high degradation efficiency, broad applicability, and minimal waste production. However, advanced oxidation also has some drawbacks, such as the high cost, the need for optimal conditions, and the potential for toxic intermediates.

5 Biological treatment

Biological treatment is a method that uses microorganisms, such as bacteria or fungi, to biodegrade or biotransform organic contaminants, such as PFAS, in water. The microorganisms can use the contaminants as carbon or energy sources and convert them into less harmful substances. Biological treatment can be performed in different modes, such as aerobic, anaerobic, or cometabolic, and in different systems, such as bioreactors, biofilters, or wetlands. The main advantages of biological treatment are its low cost, natural occurrence, and sustainability for PFAS removal. However, biological treatment also has some challenges, such as the slow kinetics, the low specificity, and the uncertainty of the end products.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?