Health and Environmental Concerns 

Both PFAS and PFOA have been linked to: 

Because they do not break down easily, PFAS chemicals accumulate in water, soil, and living organisms, making them a significant environmental and public health concern. Many governments and agencies are working on regulating and removing PFAS from products and water supplies.

Recently, the EPA set the national Maximum Contaminant Level for PFAS at 4.0 ppt (parts per trillion). The EPA (Environmental Protection Agency) is a U.S. federal agency responsible for protecting human health and the environment. Established in 1970, the EPA develops and enforces regulations to address air and water pollution, hazardous waste management, and environmental sustainability.

Since the EPA is the source of truth for how much PFAS/PFOA substances should be in the water, let's see what they say about PFAS/PFOA. They just so happen to have a "whitepaper" on this very subject. In this article, they articulate what methods they believe are the best at removing PFAS from the water supply. Here is what they say (in part):

Certain technologies have been found to remove PFAS from drinking water, especially Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), which are the most studied of these chemicals. Those technologies include activated carbon adsorption, ion exchange resins, and high-pressure membranes. These technologies can be used in drinking water treatment facilities, in water systems in hospitals or individual buildings, or even in homes at the point-of-entry, where water enters the home, or the point-of-use, such as in a kitchen sink or a shower.

Let's look at each of these technologies and see what might be the best for you and your family.

Activated Carbon Treatment

Among the various methods explored for eliminating PFAS from water, activated carbon treatment stands out as the most extensively researched. This method relies on activated carbon, a material commonly employed in drinking water systems to capture synthetic chemicals, organic matter, and compounds affecting taste and odor. The process behind it, adsorption, occurs when substances like PFAS accumulate on the surface of a solid from a liquid phase. Activated carbon's effectiveness stems from its high porosity, which maximizes the available surface area for contaminant capture.

Granular activated carbon (GAC), a widely used form of activated carbon, is derived from carbon-rich materials such as coal, lignite, and wood. In drinking water filtration, GAC has proven highly effective at trapping PFAS when applied after particulate removal. According to EPA researcher Thomas Speth, GAC can achieve complete PFAS removal for a limited time, with performance influenced by factors such as carbon type, bed depth, water flow rate, temperature, and the presence of other organic matter or contaminants. Notably, GAC performs better on longer-chain PFAS like PFOA and PFOS, whereas shorter-chain variants, such as PFBS and PFBA, are not as readily adsorbed.

Another variation of this treatment is powdered activated carbon (PAC), which consists of the same base material as GAC but in a finer, powder-like form. Unlike GAC, PAC cannot be used in continuous filtration systems and must instead be mixed directly into water before being removed along with other particulates during clarification (e.g., microfiltration or ultrafiltration). While PAC can achieve moderate PFAS reductions, it is generally less efficient and cost-effective than GAC. Speth notes that even at high doses, PAC struggles to remove significant amounts of PFAS, and its use presents an additional challenge; proper disposal of PFAS-laden sludge.

High-Pressure Membranes (aka Reverse Osmosis)

Advanced filtration technologies like nanofiltration and reverse osmosis have proven highly successful in removing PFAS from water. Of these, reverse osmosis employs a denser membrane structure than nanofiltration, allowing it to block nearly all dissolved salts, whereas nanofiltration primarily removes hardness while permitting sodium chloride to pass through. This distinction makes nanofiltration useful for filtering out contaminants while preserving certain minerals that reverse osmosis would otherwise eliminate.

Studies indicate that both membrane types achieve over 90% efficiency in capturing various PFAS, including shorter-chain compounds that are often more difficult to remove. In practice, around 80% of the incoming water, known as feed water, passes through the membrane as treated water, while the remaining 20% becomes a concentrated waste byproduct. Managing this waste stream presents a challenge, especially when dealing with PFAS, as disposal options are limited. EPA researcher Thomas Speth notes that this issue makes high-pressure membranes particularly suitable for small-scale applications, such as residential water filtration, where waste volumes are more manageable.

For those seeking more details on water treatment methods for PFAS removal, the EPA offers an interactive Drinking Water Treatability Database. This resource provides insights into over 65 contaminants and covers 34 treatment processes, allowing users to explore technologies based on specific pollutants or treatment approaches.

Ion Exchange

Anion exchange treatment, often referred to as ion exchange resin technology, offers another method for PFAS removal. These resins consist of durable, highly porous polymer materials that resist acids, bases, and water. Composed of hydrocarbon-based beads, ion exchange resins fall into two main categories: cationic and anionic. Cationic resins, which carry a negative charge, effectively capture positively charged contaminants, while anionic resins, with their positive charge, are well-suited for removing negatively charged substances like PFAS. 

Functioning similarly to powerful microscopic magnets, anion exchange resins (AER) attract and trap PFAS molecules, preventing them from passing through the water system. Research indicates that AER has a strong capacity for binding many PFAS compounds, though it is generally costlier than granular activated carbon (GAC). Among the available options, single-use AER followed by incineration appears to be one of the most promising approaches. A major advantage of this method is that it eliminates the need for resin regeneration, thereby avoiding the creation of additional waste streams that require disposal. 

Much like GAC, AER can achieve complete PFAS removal for a certain period. Its effectiveness depends on several factors, including the type of resin used, the depth of the resin bed, water flow rates, the specific PFAS targeted, and the presence of other organic matter and contaminants in the water. 

Conclusion 

Any of these methods can be effective in removing PFAS, but never forget that reverse osmosis removes the widest spectrum of contaminants of any water treatment process. So, not only are you removing PFAS, but you are also removing many other types of contaminants as well. Reverse osmosis (RO) is a highly effective water treatment method that removes a wide range of contaminants. Here’s a list of common contaminants that RO systems can remove: 

Physical Contaminants: 

Chemical Contaminants: