Understanding Total Organic Carbon impacts in Reducing PFAS in Water
Marmon Water, Inc
How-to resources, Supporting Evidence, Tips from Experts to guide Water Treatment Specialists and Distributors.
With the recent U.S. Environmental Protection Agency (EPA) regulations targeting PFAS reduction, Total Organic Carbon (TOC) has emerged as a critical factor in achieving compliance. Within this article, we aim to explain the impact of TOC on filtration systems and how it affects the removal of PFAS from drinking water.
What is TOC?
Total Organic Carbon (TOC) measures the carbon content in water derived from organic molecules. These organic molecules come from natural sources, such as decaying leaves and microbes, and accumulate in water bodies like rivers and reservoirs. Whether municipalities source water from rivers or groundwater, TOC is always present.
Municipal water treatment typically involves using oxidizers, such as chlorine or ozone, to eliminate microbes. This oxidation process breaks down larger organic molecules into smaller ones, resulting in a mixture of thousands of molecules that comprise TOC. While generally harmless at low levels, TOC can interfere with water treatment processes aimed at reducing PFAS.
PFAS Removal Methods
PFAS, or per- and polyfluoroalkyl substances, are a group of man-made chemicals that have been found in water supplies. The US Environmental Protection Agency (EPA) recommends 3 primary methods for PFAS reduction: Activated Carbon, Ion-Exchange Resin, Reverse Osmosis Systems (not covered in this post).
Impact of TOC on PFAS Removal
TOC can significantly hinder the effectiveness of both activated carbon and ion-exchange resins in removing PFAS. Some TOC molecules are structurally similar to PFAS molecules, leading to competition for adsorption sites on activated carbon and ion-exchange resins.
With TOC present at levels up to a million times higher than PFAS, the efficiency of PFAS removal can be drastically reduced.
Real-World Implications for Water Treatment
Consider a study comparing the water from municipalities with different TOC levels.
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A municipality in North Carolina with a TOC level of less than 0.3 ppm achieved 84,000 bed volumes of granular activated carbon before PFAS breakthrough.
In contrast, a Florida municipality with a TOC level of 4.6 ppm only managed 750 bed volumes before PFAS breakthrough.
This drastic difference highlights the impact of TOC on the longevity and effectiveness of PFAS treatment systems.
If a municipality does not yet remove PFAS, then the amount of TOC in the water will determine the life of a point-of-use or point-of-entry filter that contains activated carbon and/or ion-exchange resin. Unfortunately, there is no easy way to test for TOC on site; it requires special analytical instrumentation. However, you can check your municipality’s water report. Note, however, that TOC varies from season to season if your municipality is supplied by surface water.
Opportunities for Innovation
The challenges posed by TOC present significant opportunities for innovation in the water treatment industry:
Conclusion
Understanding and managing TOC is crucial for effective PFAS reduction in drinking water. Water plant managers must consider the impact of TOC on their filtration systems and explore innovative solutions to enhance PFAS removal efficiency. With ongoing advancements in filtration technology and real-time monitoring, the water treatment industry can rise to the challenge of providing safer, cleaner water for all.
About the Author
Steven Woltornist is a senior manager of product development at Marmon Water, Inc Residential Filtration. He holds a PhD in chemistry and specializes in developing advanced filtration solutions for contaminants, including PFAS.
About Marmon Water Residential Filtration
Marmon Water Residential Filtration KX Technologies | Filtrex Technologies Pvt Ltd , a subsidiary of Berkshire Hathaway , leads in point-of-use drinking water filtration. We provide innovative solutions and are a trusted partner for original equipment manufacturers worldwide.