This article originally appeared in Water Quality Products magazine April 2020 issue as "Think Bigger"
By now, most people are familiar with the lead epidemic throughout the U.S. and the world, but few consumers understand emerging contaminants. Water quality issues make news headlines every day, and art imitates life. Just last month, a major motion picture called “Dark Waters” launched nationwide to positive reviews and more than $11 million in ticket sales. The movie, set in Parkersburg, West Virginia, is based on true events surrounding deadly water pollution from the town’s largest employer.
What Are Emerging Contaminants?
What exactly are emerging contaminants? These are chemicals that can be detected at trace levels but for which the risk to human health is not yet completely known. They are also called “contaminants of emerging concern,” and for the most part, are not yet regulated under environmental laws. The list includes pharmaceuticals, personal care products, pesticides, herbicides and endocrine-disrupting compounds.
These pollutants make their way into our water supply at all points in the water cycle. Many of these man-made chemicals are not found naturally in the environment, and they do not go away or break down. As a result, they have been nicknamed “forever chemicals.” One example is per- and polyfluoroalkyl substances (PFAS), a name collectively given to a long list of different compounds. They are typically separated into two groups–long-chain and short-chain PFAS. Long-chain PFAS compounds are typically perfluoroalkyl sulfonic acids with more than six carbons, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These long-chain PFAS compounds have the potential to bioaccumulate in the human body like other well-known pollutants such as dichlorodiphenyltrichloroethane, also known as DDT and lead. Short-chain PFAS have fewer carbons, such as perfluorobutanoic acid (PFBA), which means their chemical half-life is shorter, but so far, research shows they are just as toxic to humans.
According to the U.S. EPA, there are more than 600 PFAS compounds that can be imported into the U.S. It is important to note that the federal government does not yet regulate PFAS nationwide; however, EPA has a guidance level of 70 parts per trillion (ppt) for PFOA and PFOS. Many states have established guidance levels and enforceable maximum contaminant levels (MCLs) for specific PFAS that are of concern in their territory.
PFAS came into common use in the 1940s and were once thought beneficial because of the ability to repel fire, water, oil and stains. They have been used in stain and water-resistant fabrics, non-stick products, polishes, pizza boxes, waxes, paints, cleaning products and fire-fighting foams. PFAS water contamination is often found in areas with proximity to specific manufacturing facilities, or in the case of fire-fighting foams, near points of use. Once these chemicals have been spilled and are in the groundwater, they are there to stay. Scientists can track their migrating progression from one community to the next through both groundwater and surface water. Health officials have linked these chemicals to various cancers, cholesterol diseases, pregnancy-induced hypertension and preeclampsia, and thyroid disorders.
Several major U.S. corporations have a history of using these chemicals in their products, including DuPont and 3M, with major household brand names such as Teflon, Goretex and Scotchguard. In the past two decades, the companies found alternatives to PFAS that were believed to be safer.
They were not. The next evolution of chemicals included GenX, which is currently a major pollutant in the Wilmington, North Carolina, watershed, affecting more than 1.5 million people.
Consumers want more than just clear, great tasting water. They want to know the water they bathe in, drink and cook with is safe. Water filtration experts can educate their customers on the issues and provide solutions at the same time.
PFAS Removal Technology Evolves
As analytical equipment evolves, making testing more sensitive, so does the technology to address the results. PFAS, just like lead, has been around for ages, but instrumentation has become more sophisticated. As a result, we are becoming more aware
of the pollution, as well as its related harmful effects.
It is not reasonable to expect entire families, businesses or communities to use slow-flow pitchers with long contact times for all their household needs. It may work for small batch drinking water in the short term, but the human body’s largest organ is our skin–what about showers, baths, laundry, cooking? What happens when your family members go to school or work? How about eating at a restaurant or staying in a hotel?
While the most proven technologies to remove these contaminants include reverse osmosis, ion exchange resins and granular activated carbon absorption, none have provided a reliable high-flow, high-capacity filtration system that removes pollutants at a rate that will sustain a whole school, office building, hotel or community.
Reverse osmosis (RO) has a variety of drawbacks, but at the top of the list is the slow flow, costly investment and waste of water. Ion exchange resins have the drawback of being inefficient because filtration is limited to the surface area of the beads only and requires regeneration that creates another highly contaminated waste stream. Granular carbon is more porous, providing more surface area, making it more efficient. However, a granular carbon system large enough for point-of-entry (POE) filtration for homes, offices, schools or restaurants would involve massive tanks that would need to be 6 feet or larger.
PFAS Removal at Point-of-Entry
The scientists at GreenStory Global Water Filtration have developed new medias specifically for lead, metals, pesticide/herbicide contaminants along with another for PFAS which is both compact and efficient. Past PFAS filtration solutions have been limited to either long chain or short chain molecules, so only half of the toxic chemicals would be filtered out with a specific solution. This new PFAS removal media is effective at both and has a significantly smaller footprint than traditional granular carbon media.
These specialty medias allow the removal of contaminants at much higher flow rates and higher capacity than previous solutions. The GreenStory Global team has developed a way to incorporate the proprietary medias into cartridges for scalable POE installation. In fact, they can be installed in any size school, office building or community and will not restrict normal flow.
Each lead, metal, pesticide/herbicide removal cartridge has a capacity of >120,000 gallons with a flow rate of 11 gallons per minute. It has been tested and certified to NSF/ANSI 53 2018, 22.214.171.124, 6.5 pH and NSF/ANSI 53 2017, 7.4.3, 8.5 pH lead reduction. The PFAS removal cartridge has a flow rate of 60 gallons per minute and IAPMO has certified it to NSF Standard P473 for PFOAS Reduction. The system can remove 98% of the very high influent solution, exceeding the EPA requirement to reduce PFAS to less than 70 parts per trillion, which is the EPA guidance level for PFOA and PFOS.