An Introduction to PFAS in Drinking Water

What are PFAS?

Per- and Polyfluoroalkyl Substances (PFAS) are man-made chemicals invented in the 1940s that have been used ever since to make fluoropolymer coatings and products that resist heat, oil, stains, grease and water. PFAS do not degrade naturally due to their highly resilient carbon-fluorine bond (the reason they are known as “forever chemicals”). PFAS are either “short-chain” or “long-chain” PFAS, which refers to the length of the carbon backbone of each molecule.

They have been used in firefighting foam and thousands of consumer products such as cookware, food packaging, water-repellant clothing and personal care products.

PFAS are quickly becoming recognized as a public health threat, with growing activity in local, state and federal regulations.

How to treat PFAS has become an “all hands on deck” effort, and municipal water utilities and their engineers of record around the world are actively seeking effective and affordable answers to the question of how to remove PFAS from water.

What are the health dangers of PFAS in drinking water?

Because of their widespread use and their persistence in the environment, PFAS are found in the blood of people and animals all over the world. There are thousands of different PFAS, some of which have been more widely used and studied than others.

Scientific studies have shown that exposure to certain levels of PFAS may lead to:

• Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women
• Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations or behavioral changes
• Increased risk of some cancers, including prostate, kidney and testicular cancers
• Reduced ability of the body’s immune system to fight infections, including reduced vaccine response
• Interference with the body’s natural hormones
• Increased cholesterol levels and/or risk of obesity

Are PFAS regulated for drinking water?

PFAS in drinking water is a growing area of government regulation worldwide. In April of 2024, the U.S. EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS in drinking water, establishing legally enforceable Maximum Contaminant Levels (MCLs) for PFOA, PFOS, PFHxS, PFNA, and HFPO-DA. For PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS, the regulation uses a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. The EPA also finalized health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS.

This regulated group of PFAS includes both short-chain and long-chain types. The final rule requires:

• Public water systems must monitor for these PFAS and have until 2027 to complete initial monitoring, followed by ongoing compliance monitoring. Water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027.
• Public water systems have until 2029 to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
• Beginning in 2029, public water systems that have MCL-exceeding PFAS in drinking water must take action to reduce levels of these PFAS and must notify the public of the violation.

The U.S. EPA also has designated two PFAS long-chain compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), as “hazardous substances” under the federal program, Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also known as Superfund). This designation allows the EPA to regulate PFAS in wastewater; however, the EPA has indicated that, rather than pursuing municipal wastewater plants and other “passive” facilities that did not create PFAS or add them to the wastewater, it will focus on regulating entities that significantly contributed to the release of PFAS into the environment, such as PFAS manufacturers and those using PFAS in their manufacturing processes.

Bans on the manufacture and use of PFAS began emerging all over the world several years ago from various countries, states and regulatory bodies. Some of those bans are already in effect, and many more are scheduled to take effect by 2030.

Are PFAS widespread in drinking water?

Yes, there is ample data showing that PFAS are widespread in drinking water, which is why it’s important for drinking water systems to quickly learn how to treat PFAS in water.

According to the latest Environmental Protection Agency (EPA) data, at least 70 million Americans get their water from a system where PFAS have been found at levels that require reporting to the EPA. A study done by the U.S. Geological Survey (USGS) shows that at least 45% of the nation’s tap water is estimated to have one or more types of PFAS.

Worldwide, 31 percent of groundwater samples and 16 percent of surface water samples contained PFAS, according to research published by Nature Geoscience.

How to remove PFAS from water

The current leading solutions for how to treat PFAS in water are ion exchange (IX) and granular activated carbon (GAC). Determining which of these is the best option for the lowest capital and/or operating expense requires a complete water profile that includes a water analysis, contaminant targeting, evaluation of other technologies already on site, assessment of space limitations and calculations of the volume of water needing decontamination now and into the foreseeable future.

Ion Exchange (IX): Using a synthetic resin media specifically designed for targeting PFAS, IX is positively charged to attract PFAS particles. It is better at both short-chain and long-chain PFAS removal than GAC and can reduce PFAS to non-detectable levels (as much as 99.99% removal) using a very short (2-3 minutes) empty bed contact time (EBCT). The short EBCT allows for a smaller installation and therefore contributes to a reduced capital expense.

This single-use media offers the longest life of its kind on the market, and once it is exhausted, it is removed and sent off-site for thermal destruction (at present the most common option for destroying PFAS).

Granular Activated Carbon (GAC): A long-proven technology for contaminant removal, GAC has strong market acceptance and a low operating cost. Also able to reduce PFAS to non-detectable levels, GAC works best with long-chain PFAS and not as well with short-chain PFAS as IX. However, compared to IX, it does have the advantage of being able to remove additional contaminants and disinfection by-products. At 10-20 minutes, its EBCT is longer than IX and requires a larger footprint, which increases capital expenses. As with single-use IX, spent media must be removed and sent off for incineration.

Why work with De Nora?

De Nora deeply understands water treatment and how to treat PFAS , with tens of thousands of installations globally over decades of experience and particular expertise in PFAS pilots and PFAS remediation. Partners receive excellence in service throughout the entire relationship, offering benefits such as site audits for optimization of existing systems, start-up and training, process guarantees for media exchange, and complementary media change out and haul away.

De Nora’s offerings for PFAS removal are tailored systems designed to achieve regulatory compliance for a wide range of flow and treatment needs. De Nora offers both IX and GAC for PFAS removal in systems that maximize uptime, cost efficiency and ease of operation.

As stakeholders peel back the layers of PFAS remediation, De Nora is dedicated to following every complicated thread until PFAS are no longer a threat to human health and the environment.