Per- and polyfluorinated substances (PFAS) continue to dominate the conversation as an emerging contaminant of concern due to their potential for adverse human health effects and continued regulation. This group of chemicals can be found in a wide variety of consumer products and drinking water. With the recent news of more stringent EPA regulations and funding opportunities, water municipalities are diligently looking into technologies currently available to treat PFAS and begin incorporating these solutions into existing processes.
PFAS treatment technologies are typically divided into three broad groupings: concentration, separation and destruction technologies. Concentration technologies, such as reverse osmosis (RO), are designed to transfer PFAS from the forward flow to a lower-volume waste stream. Media-based separation technologies like ion exchange (IX) and granular activated carbon (GAC), remove PFAS from the forward flow and capture it in the media for disposal. Destruction technologies are not currently approved by the EPA for PFAS removal from drinking water, but many manufacturers are in development and testing of the technology.
The EPA has identified three approved approaches to PFAS reduction:
- Granular activated carbon. GAC, the most commonly used type of PFAS treatment, adsorbs PFAS on the media until the media is spent and needs to be replaced, with either virgin material or regenerated at a facility. Regeneration through GAC decreases disposal costs and adds security to the supply chain. GAC also has lower hydraulic requirements than RO or IX but a higher capital cost than IX due to larger system requirements. This popular treatment solution has many carbon options available, each of which has various benefits and drawbacks that should be tested and recorded.
- Ion exchange. IX uses small resin beads to exchange ions with PFAS compounds. It is typically single-use media that is disposed of once it is spent. IX has a smaller footprint than GAC because of the higher loading rates and lower bed contact times. There are numerous types of resin that are specially formulated to remove PFAS. IX also has higher head loss through vessels due to higher loading rates.
- Reverse osmosis. RO uses high pressure to push water through a membrane, removing contaminants while allowing water to pass. RO has high pressure requirements and brine disposal can be complicated and expensive. It may need to be used in conjunction with other technologies, such as GAC or IX, if a side stream is used. RO is typically operated as a side-stream process with blending. Blending may be limited when used for PFAS treatment.
Technology options will continue to emerge and evolve to help treat ongoing PFAS issues as regulations change. Water municipalities have the opportunity to prepare today and explore what technology may be optimal for their system from an infrastructure and budgetary perspective.
It's vital to keep communities' drinking water safe and treated for emerging contaminants. Learn more about how to approach PFAS water and wastewater treatment solutions.
