The perfect solution has been elusive, but effective approaches exist
Per- and polyfluorinated substances (PFAS) have come under intense scrutiny in recent years, often bearing the popular name “forever chemicals” for their resistance to breaking down in the environment. PFAS are found in a range of products from dental floss and nonstick pans to waterproof fabrics and food packaging. They seem to be everywhere and their longevity, widespread use, and potential negative impacts on human reproductive, immune, cardiovascular, and endocrine health have driven efforts to regulate them.
A perfect technical solution for PFAS treatment remains elusive, but the Environmental Protection Agency (EPA), water treatment providers, and utilities are investigating ways to protect the public.
EPA Announces PFAS Rule
The EPA’s recent PFAS National Primary Drinking Water Regulation (NPDWR) for six PFAS chemicals has established regulatory standards. Funding opportunities are in the pipeline to accompany the new rule. The EPA estimates that the rule will protect 100 million people from PFAS exposure, save thousands of lives, and prevent tens of thousands of serious illnesses.
The NPDWR sets legally enforceable maximum contaminant levels (MCLs) in drinking water for six chemicals: PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, along with PFAS consisting of two or more of PFHxS, PFNA, HFPO-DA, and PFBS. The EPA has also established nonenforceable, health-based maximum contaminant level goals for PFAS.
For the EPA rule, the Bipartisan Infrastructure Law provides $1 billion to assist states and territories in testing and treatment as public water systems work toward compliance with the new standard, and well owners attempt to address PFAS contamination.
Public water systems must monitor drinking water for the six PFAS chemicals and finish initial monitoring by 2027. Compliance monitoring must continue after that date and the public must be informed about PFAS levels in their drinking water. Public water systems will have until 2029 to install solutions for PFAS levels above the MCLs. Beginning in 2029, public water systems with PFAS problems must reduce the levels in their drinking water and notify the public of any violations.
Research and development of PFAS treatment technologies is ongoing, and many advances are likely. Currently, however, utilities face uncertainty about compliance. While no existing technology is perfect, the water sector has three general approaches to PFAS treatment: concentration, separation, and destruction.
Concentration: Nanofiltration and Reverse Osmosis Solutions
Approved by the EPA for the treatment of PFAS, concentration technologies include filtration methods such as nanofiltration and reverse osmosis, which move PFAS from the forward flow and concentrate them in a smaller waste stream.
Nanofiltration uses membranes with small pore sizes (approximately 1 nanometer) to remove a wide range of contaminants, including PFAS. This method is effective because it allows water molecules to pass through while blocking larger molecules like PFAS, making it a valuable option for improving water quality.
Reverse osmosis (RO) pushes highly pressurized water through semipermeable membranes that reject contaminants like PFAS, and the purified permeate passes through. It can also be used concurrently with other processes if a side stream is used.
While municipalities work on installing large-scale reverse osmosis treatment plants, smaller RO systems are a viable solution for homeowners. By installing a reverse osmosis system at the point of use, such as under the kitchen sink, homeowners can effectively purify their tap water, ensuring it is safe and clean for daily consumption. This makes RO a preferred method for individuals who may be in areas affected by PFAS, providing peace of mind about the quality of their household water.
Separation: Granular Activated Carbon and Ion Exchange
Media-based separation technologies such as granular activated carbon and ion exchange capture PFAS from the forward flow in filtration media, which is then disposed of. The EPA has approved carbon and ion exchange for PFAS reduction.
Granular activated carbon (GAC) is the dominant PFAS treatment approach. It adsorbs PFAS until it is saturated and must be replaced with new or regenerated media. Media regeneration cuts disposal costs and adds resilience in case of shortages. Hydraulic requirements for carbon filtration are lower than for reverse osmosis or ion exchange. Capital cost is, however, higher than for ion exchange.
In ion exchange, contaminated water is passed through small resin beads. Ions attached to the surface of the beads are exchanged with PFAS ions, removing them from the water. This technology requires a smaller footprint than GAC because of higher loading rates and shorter bed contact times. Many resin types have been designed specifically for PFAS removal. One drawback of ion exchange is that it leads to higher pressure loss in pipes because of its higher loading rates.
Destruction: Still a Work in Progress
High-temperature methods like incineration and electrochemical oxidation are being tested as means to destroy PFAS molecules. Many additional technologies that have been emerging lately attempt to break down PFAS into less harmful chemicals like carbon dioxide and water. While these and several other destruction technologies are in the research and development phase, they are not EPA-approved for the treatment of PFAS in drinking water production.
PFAS Treatment Requires Expert Knowledge
Selecting the right technology and strategy for PFAS removal can be complex, with many factors to consider. At Seven Seas Water Group, we stay at the forefront of technology and regulatory changes to provide our clients with the most effective and compliant solutions. Our commitment extends beyond installation to ongoing operations and maintenance, ensuring that water treatment plants continue to meet evolving standards and protect public health.
By understanding and utilizing advanced treatment technologies like reverse osmosis, communities and individuals can take proactive steps to reduce their exposure to PFAS and ensure their water is safe for consumption. We’re here to help guide these efforts and ensure that water remains clean and safe for future generations. Contact Seven Seas to discuss your water treatment challenges.
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