On Aug. 23, 2018, the U.S. Environmental Protection Agency (EPA) published its results of efforts to study a variety of technologies used to remove Per- and polyfluoroalkyl substances (PFAS) from drinking water. PFAS are a group of man-made chemicals that includes PFOA, PFOS, GenX and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. PFOA and PFOS have been the most extensively produced and studied of these chemicals. Both chemicals are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. However, 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.
Granular activated carbon (GAC) is the most common, and most studied treatment technology. It relies on adsorption, the physical and chemical process of accumulating a substance on another media to remove it from the underlying water matrix. It works especially well with so-called long-chain PFAS like PFOA and PFOS and is a well-known treatment technology for other organic contaminants. It remains to be seen how cost effective it can be, especially for treating large volumes of water. All of the treatment technologies reviewed by EPA can be explored in EPA’s interactive Drinking Water Treatability Database which covers 34 processes identified to treat over 65 different contaminants. The database is sortable by either contaminant type or treatment technology type.