PFAS Water Treatment
Per- & Poly-fluoroalkyl substances (PFAS) including PFOS, PFOA form a dangerous group of “Forever Chemicals” which cause health effects and are difficult to treat.
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the most common water contaminants in the family of PFAS chemicals. These manufactured compounds are non-naturally occurring, don’t break down in the environment, and can cause severe health effects. PFAS have been used in consumer goods and in firefighting foams for decades without understanding the potential long-term problems. PFOA & PFOS contamination of water has been overlooked until recently. Even small concentrations can cause health effects, so current EPA drinking water recommendations for PFAS compounds are in the parts-per-trillion (PPT) range. Effective treatment of PFOS, PFOA, and other PFAS chemicals will be important at many active and former industrial sites in upcoming years.
People can be exposed to PFAS chemicals in several ways, most commonly through drinking water contaminated with PFOS & PFOA. Manufactured PFAS chemicals do not degrade naturally and can remain in water plumes and aquifers indefinitely. While these “forever chemicals” are very difficult to breakdown, they can be filtered and removed from water. H2K Technologies provides proven solutions for PFAS water treatment, including activated carbon and ion exchange resin. Specific water treatment equipment will vary with concentration and individual site characteristics, and our engineering team will help you select the most effective and efficient technology.
Activated carbon filtration is common in water treatment for volatile organic compounds, it is also an effective solution for PFAS contamination. Activated carbon works by catching contaminants on the highly porous surface. The atomic structure of PFOA and PFOS has a hydrophobic (water-repellent) tail and a hydrophilic (water-attractive) head. Carbon vessel design must account for this unique structure to provide complete PFAS removal. Carbon contact time (EBCT) for PFAS treatment is longer than what’s required for most VOC removal. Carbon grade and pore surface area also must be optimized, engineered virgin-grade carbon provides the best surface for removal of PFOS & PFOA.
Carbon filters capture a wide range of contaminants, and water impacted with other compounds in addition to PFAS can consume carbon capacity quickly. Ion exchange resin is a more selective option for PFAS removal from water. At first glance, ionic resin treatment looks similar to carbon treatment, but the mechanics are different. Resin water treatment uses synthetic media with ionic charges to remove contaminants from water. Ion exchange resin can be designed as a more selective water treatment for specific compounds, such as PFOS & PFOA. The negatively charged resin surface attracts PFAS compounds and captures them in the media bed. This selective treatment is the best choice when water contains other organic or solids loading which would compete for pore surface on carbon.
Our experienced team of engineers can review sampling data, model treatment performance, recommend treatment approach and estimate the media lifespan for your project. Our expertise will help you provide a custom turnkey solution to provide effective results for the lifespan of a project. Click below for additional information about filter vessels for activated carbon and ion exchange resin.
Key PFAS Concepts
PFAS = Per- & Poly-fluoroalkyl substances, the broad class of man-made compounds composed of multiple fluorine atoms bonded to an alkyl chain.
PFCs = Perfluorinated chemicals, an alternative reference to PFAS compounds. This usage is being phased out due to confusion to perfluorocarbons, which are greenhouse gases.
PFOS & PFOA = Perfluorooctane sulfonic acid and perfluorooctanoic acid, the most commonly occurring PFAS compounds known to cause health effects in humans.
PFNS, PFNA, PFDS, PFDA – Other PFAS compounds of interest, less commonly occurring than PFOS & PFOA.
Activated carbon – A water treatment technology which filters PFAS in pores on the carbon surface.
Ion exchange resin – A water treatment technology which removes PFAS from water with ionic charged filter media.