PFAS, which stands for Polyfluoroalkyl Substances, are synthetics found in various household products, firefighting foam, and numerous other situations in industry. Despite this advisory level, there are currently no regulations on PFAS levels in drinking water, leaving citizens concerned about their water’s safety.
One common method for treating PFAS contaminated water is reverse osmosis (RO). But how well does it work? Does reverse osmosis remove PFAS? Reverse osmosis can remove the vast majority of PFAS from your water supply, but it may not remove them all.
How does reverse osmosis remove PFAS, and what are some of the alternatives? Let’s dive in.
Reverse Osmosis: A Proven PFAS Removal Option
Reverse osmosis processes represents a well-established option used for years to remove contaminants. This process involves pushing contaminated water directly through a semi-permeable membrane, removing a variety of contaminants, and producing clean drinking water. RO can remove the vast majority of PFAS from the water supply, making it more effective than most other options.
What is Reverse Osmosis?
Reverse osmosis is a process that uses changes in pressure to remove contaminants from the drinking water. The filter membrane has small pores, enabling it to remove a number of impurities, including PFAS, lead, arsenic, chlorine, heavy metals, mercury, pathogens, nitrates, pesticides, sulfates, fluoride, and pharmaceuticals.
Reverse osmosis has been used to clean our water supplies for a long time, and it is one of the most frequently used methods for addressing PFAS contamination. The water containing the PFAS chemicals is sent through the membrane, and the filters remove the larger molecules containing contaminates or minerals, leaving treated water to pass through.
Reverse osmosis filters recycle water using the membranes continuously, concentrating waste into a smaller volume. This final solution, called brine, eventually becomes heavily saturated with PFAS and other filtered molecules.
Types of RO Systems for PFAS Removal
You can choose from a number of options, including systems for the whole house and point-of-use systems, usually shortened to POU. POU RO systems are relatively compact, attaching right under the faucet in your kitchen. This can be contrasted with whole house water filters that treat all of the water as it enters your house, ensuring safe drinking water throughout.
POU: Reverse Osmosis at the Point of Use
A point-of-use RO system treats water at the point it is used, and it is often installed as a filter that goes under the sink in the kitchen. The system gives you drinking water that you can get directly from the system, discharging PFAS concentrated brine right into the drain.
A point of use RO option uses a number of cartridges, including a particulate filter, a carbon filter, and the membrane cartridge tied to the RO system. Tankless reverse osmosis systems are suitable for smaller homes with limited storage space, as they eliminate the need for a tank.
Reverse Osmosis Systems for the Whole House
Whole-house reverse osmosis systems are installed at the location where a home’s water supply comes into the building, treating all of the water coming into your home. These systems consist of a prefilter, a sediment filter, a reverse osmosis membrane cartridge, and sometimes even a carbon postfilter.
Whole-house systems ensure clean water at every faucet and sink in your house, providing added protection against PFAS and other contaminants. These are more expensive than larger than point-of-use systems, and whole-house RO systems are usually unnecessary.
Limitations of Reverse Osmosis for PFAS Removal
While reverse osmosis is effective at removing most PFAS, it is important to understand that the technology may not be perfect for every situation. Some of the limitations of RO for PFAS removal include:
- Maintenance: RO systems require regular maintenance, including filter replacement and membrane cleaning, to maintain their effectiveness.
- Water Pressure: Reverse osmosis relies on pressure to force water through the membrane. Low water pressure can reduce the effectiveness of the system, requiring additional booster pumps.
- Membrane Fouling: The membrane can become fouled over time, reducing its efficiency. Regular cleaning and maintenance can prevent this issue.
- Brine Disposal: The concentrated waste brine containing PFAS and other contaminants must be disposed of properly to prevent environmental contamination.
For these reasons, it is important to think about some of the alternatives to a reverse osmosis system as well.
Alternatives to Reverse Osmosis for PFAS Removal
While reverse osmosis is highly effective at removing PFAS from drinking water, it’s not the only option available. Two other popular methods for removing PFAS and other contaminants include granular activated carbon (GAC) and resin for ion exchange. These alternatives have their own unique advantages and can be suitable options for certain situations.
Granular Activated Carbon Filters for PFAS Removal
Granular activated carbon is a strong material that excels at removing a variety of molecules from water. GAC can get rid of PFAS, but it may not be as strong at treating shorter compounds designed to replace some of the toxic chemicals we used in the past. Nevertheless, GAC remains a highly effective option for PFAS removal.
Research by the EPA has shown that activated carbon filters can do a great job at filtering and removing PFAS from the water supply. As a result, activated carbon treatment is both cost-effective and efficient at removing a wide range of harmful pollutants, including PFAS.
Anion Exchange Resins for PFAS Removal
Ion exchange resin, the main component in water softeners, may remove PFAS from drinking water supplies, if it is an anion exchange resin. Most water softeners use cation exchange resins, not anion exchange resins. The difference, while subtle, matters in this case.
According to a direct quote from the EPA, “The negatively charged cationic exchange resins (CER) are effective for removing positively-charged contaminants and positively charged anion exchange resins (AER) are effective for removing negatively charged contaminants, like PFAS.”
Therefore, if your water softener uses an anion exchange resin, it may remove PFAS; however, an anion exchange resin is not the default option in most water softeners. The resin can get saturated as time goes on, so be sure to replace the resin as needed to be sure it is clean and effective.
Comparing Alternatives: GAC vs. Ion Exchange Resins
Both granular activated carbon and anion ion exchange offer effective solutions for removing PFAS from drinking water. When deciding between the two, it’s essential to consider factors such as the specific PFAS compounds present in your water supply, your budget, and your household’s water consumption.
GAC is often more cost-effective than anion ion exchange. However, anion ion exchange may provide a more comprehensive removal of a wider range of PFAS compounds, including newer variants like GenX. Ultimately, the choice between GAC and ion exchange resins will depend on your unique circumstances and water treatment goals.
Rely on DROP Reverse Osmosis Systems and Water Filters To Protect Your Home’s Drinking Water
At DROP, we understand the importance of providing safe, clean water for your home. Our reverse osmosis system, smart water softeners, and water filters are designed to meet your specific needs, ensuring your home’s water supply is free of harmful contaminants.
Our expert team can help you choose the right system for your home and guide you through the installation process, so you can have peace of mind knowing your family is protected. We understand that every home is different, and we can help you find the best system for your requirements.