Granular Activated Carbon Eliminates PFAS for a Water District in Maine

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Granular Activated Carbon Eliminates PFAS for a Water District in Maine

Water is the lifeblood of community and industry in the picturesque seacoast towns of Kennebunk, Kennebunkport and Wells, Maine, where tourism, farming and commercial fishing help drive the local economy.

That’s why, in 2016, when two prevalent perfluoroalkyl substances (PFAS) — perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) — were detected in one of the system’s supply wells, the Kennebunk, Kennebunkport & Wells Water District acted quickly to address the contamination. PFAS have extreme chemical stability, are resistant to degradation, and bioaccumulate in the blood and certain organs of the body. While the full health impact of PFAS is still being determined, lab studies have linked PFAS to liver injury as well as adverse effects on growth, development, and reproduction. 

Proactive, precautionary measures
In the KKWWD supply well, the combined level of the two contaminants, at 50 parts per trillion, was within the combined limit of 70 ppt as recommended by the U.S. Environmental Protection Agency. With the health effects of this entire class of contaminants still under investigation, KKWWD decided to proactively shut down the affected well as a precautionary measure and evaluate the best course of action.

First, KKWWD needed to solve a mystery: where did the contaminants come from? PFAS compounds are typically associated with industrial activity and the use of fire retardants at military installations. Neither of these applications were an exact match for this community. Investigation ultimately pieced together a chain of cause and effect: agricultural runoff from a local farm that had applied soil enhancers made with biosolids from a municipal wastewater plant, combined with fly ash that came from a local paper mill (since closed).

Evoqua: A technology-agnostic partner
To remove the contaminants, KKWWD turned to Evoqua to explore treatment options. Evoqua has worked with many municipalities like KKWWD as a leading provider of a full portfolio of PFAS treatment technologies, including GAC and single-pass ion exchange resin available in permanent or emergency mobile assets. With years of experience in PFAS removal and a technology-agnostic approach to filtration solutions, Evoqua was well suited to identify and provide the most cost-effective solution for the project.

KKWWD expressed a preference for GAC, based on experience and familiarity with the technology. Evoqua examined water-quality data and advised the district on a pilot test of several types of carbon, including the competitor’s, to determine which would perform best for their local water chemistry.

The Solution: AquaCarb CX enhanced coconut carbon
Testing multiple types of GAC systems turned up an effective, efficient solution: Evoqua’s patented AquaCarb 1230CX enhanced coconut-based carbon and the HP 1220SYS high-pressure liquid-phase adsorption system. Test results showed that this system, compared to other tested carbons, would provide significantly longer full-scale runtime before requiring service and reactivation. 

Download the full case study to read the results and find out more about AquaCarb CX coconut-shell carbon. 

Download Case Study


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