Emerging Compounds Treatment Technologies

Steve Woodard | ECT President & Co-FounderSWoodard@ect2.com | 207.210.1551

www.ECT2.com

Process Flow Diagram for 1,4-Dioxane Treatment

Sustainable Removal of PFAS from Groundwater Using Synthetic Media

Per- and Polyfluoroalkyl Substances (PFAS) are emerging as high-priority and high-profile contaminants.

Due to widespread contamination, many communities need large-scale treatment systems to treat

drinking water supplies for PFAS. Fortunately, synthetic media (resin) technology has shown significant

promise for treating a broad range of PFAS. Below are some of its many benefits:

• 3 to 5 times higher capacity than activated carbon for PFOS and PFOA

• System is regenerable on site, and more sustainable and cost-effective than other technologies

• Technology was successfully demonstrated at the former Pease Air Force Base in NH

• Smaller footprint, lower capital and operating costs

• Regenerant solution can be reclaimed and reused

• Broad application at PFAS-contaminated sites across the US and abroad

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PRODUCT SHEET

1,4-Dioxane Removal from GroundwaterAn ECT synthetic media system was installed at an industrial site in Massachusetts in 2011 to treat 15 gpm of contaminated groundwater. The contamination averages 20 µg/l of 1,4-dioxane and 3,000 µg/l of chlorinated volatile organic carbon (cVOC) compounds. The treatment system is part of a larger, 100-gpm hydraulic control remedy. ECT designed a modular system to allow for future relocation to an underground parking garage for a new apartment complex. The objectives of the remediation system are to: (1) provide long-term contaminant migration control; and (2) learn from this smaller system in anticipation of replacing the existing 100-gpm air stripper treatment system operating at an up-gradient location.

A new technology had to be selected, since the existing air stripper does not remove 1,4-dioxane. Synthetic media, specifically AMBERSORBTM 560, was identified as the technology more capable of improving operational reliability than other 1,4-dioxane treatment technologies. This new technology also facilitated compliance with tight permit limits (1,4-dioxane less than 3.0 µg/l, with future limits likely to drop below 1.0 µg/l), while simplifying process design and reducing long-term operating costs.

The full-scale system design was based on the results of extensive bench and pilot testing. Water is pumped in an up-flow mode through multiple synthetic media vessels operated in series, i.e. lead-lag-polish operation. The 1,4-dioxane and other contaminants preferentially adsorb to the media. Steam regeneration is performed in the vessel, in a down-flow mode. One vessel is regenerated at a time, leaving the remaining vessels in service to maintain continuous groundwater extraction and consistent treatment efficiency.

Influent 1,4-dioxane concentrations have ranged from 8 to 60 µg/l during the first two years of operation. Effluent concentrations have been consistently non-detect, at less than 1.6 µg/l, other than one brief period during startup. The ECT team quickly realized that this deviation was caused by incomplete media regeneration, and that higher steam temperatures are required to completely regenerate the media. The other contaminants, total cVOCs, have been consistently removed to non-detect levels for the entire two-year operating period. More recently, EPA Method 522 has been used during the last several months to measure 1,4-dioxane down to 0.2 µg/l. Still, the treated effluent concentrations have remained consistently non-detect.

The results of this first full-scale application demonstrate that synthetic media systems present a simple and more reliable alternative to advanced oxidation 1,4-dioxane treatment methods, which have struggled with achieving consistent, reliable results. The system has proven to be straightforward and reliable, providing consistent results over a range of treatment conditions.

Synthetic Media Vessels

Modular 1,4-Dioxane Treatment System

CASE STUDY

“The results from this first full-scale system are exciting, demonstrating that synthetic media systems present a viable alternative to conventional 1,4-dioxane treatment methods.”

www.ect2.comAMBERSORBTM is a registered trademark of The Dow Chemical Company.

For more information: Steve Woodard SWoodard@ect2.com 207.210.1551

www.ect2.com

INFLUENT AND EFFLUENT 1,4-DIOXANE

INFLUENT AND EFFLUENT TVOCS

CASE STUDY