Sustainable Removal of Poly- and Perfluorinated Alkyl Substances (PFAS) from Groundwater Using Synthetic Media

Transcription

1 Sustainable Removal of Poly- and Perfluorinated Alkyl Substances (PFAS) from Groundwater Using Synthetic Media Nathan Hagelin, Amec Foster Wheeler; Steve Woodard, ECT Amec Foster Wheeler 2016.

2 Presentation Outline 1. The team: Amec Foster Wheeler and ECT 2. PFAS sources, regulations and treatment challenge 3. An effective PFAS treatment technology: Synthetic Ion Exchange Media 1. Bench testing results 2. Pilot testing results 3. Full-scale design 4. Ongoing Research 2

3 PFAS Sources, Regulation and Treatment Challenges Sources of PFAS include firefighting foam, Teflon TM, Scotchgard TM, Gore- Tex, etc. USEPA has issued a combined drinking water Health Advisory Level (HA) for: Perfluorooctane sulfonate (PFOS) = 70 ppt Perfluorooctanoic acid (PFOA) = 70 ppt The carbon-fluorine bond is one of the strongest in nature Granular activated carbon (GAC) is accepted technology, but has limitations 3.

4 Challenge: Remediation State of the Practice Contaminants of Emerging Concern few proven technologies Recalcitrant compounds tough bonds to break Lack of enforceable standards wait and see approach Emergency response mode must use proven technology to address completed exposure pathways Most sites have not progressed beyond SI/RI Few opportunities to date for field-scale trails coming soon Proven technologies have limitations and are expensive 4 Amec Foster Wheeler 2016.

5 An Urgent Opportunity for Technology Widespread groundwater contamination emerging nationwide at military installations, airports, refineries and industrialized communities Widespread use of AFFF resulting in persistent groundwater plumes Emergency response at municipal and private drinking water supplies Fisheries shut down at some sites Widespread and troubling media coverage Proven technologies (primarily GAC) have shortcomings Innovation needed 5.

6 Synthetic Media surfaces as potential solution Bench Test Methodology and Results Isotherm Testing Column Testing Regeneration

7 Media Selection Synthetic media (resins) removes various contaminants from liquids, vapor or atmospheric streams Isotherm testing to identify potentially effective media Ion Exchange Polymeric Potential for indefinite reuse via regeneration Carbonaceous 7

8 Isotherm Results 8.

9 Bench Test PFAS Influent Concentrations PFAS Compound Average Influent Concentration (µg/l) PFOA PFOS 3.33 Other PFAS 3.11 Total PFAS

10 Bench Test Setup Isotherm testing narrowed down the field to 3 top performing synthetic media (ionexchange resins). Control Add a coloured transparent segment and caption if Resin required. B Feed pump Column tests evaluated the ability of the resins to remove PFCs from the groundwater. Resin A Resin C Ground -water drum 10.

11 PFAS Mass (ng) Adsorption and Regeneration of Leading Resins from Column Testing 450, , , , , , , ,000 PFAS Mass Delivered PFAS Mass Removed PFAS Mass Recovered 50, Resin A Resin B Resin C

12 Final Outcome of Bench Test Adsorption of PFCs to resin below detection limits No breakthrough observed Add a coloured transparent segment and caption if required. >99% regeneration of media with solvent/brine solution Success of bench test led to a pilot test for evaluation at the Site Sorbix A3F A strong base anion exchange resin 12

13 Pilot Test Setup and Methodology Influent Characterization Process Design Results

14 Site 8 Layout 14

15 Pilot Test PFAS Influent Concentrations PFAS Compound Average Influent Concentration (µg/l) PFOA 11.5 PFOS 27.4 Other PFAS 55.6 Total PFAS 94.5 Concentrations approximately 15 times higher than bench test 15

16 Pilot Test Process Flow Diagram 16 Amec Foster Wheeler 2016.

17 Pilot Test General Arrangement Process pumps GAC (front) and resin (rear) vessels Cartridge filters for solids removal 17 Amec Foster Wheeler 2016.

18 Ion Exchange Vessels 18 Amec Foster Wheeler 2016.

19 PFOA (ug/l) PFOA Breakthrough Results Influent 1 Lead GAC Lead Resin 0.1 Lag GAC Lag Resin 0.01 EPA PFOA+PFOS HA ,000 20,000 30,000 40,000 50, Amec Foster Wheeler Bed Volumes

20 PFOA breakthrough at 5-min EBCT

21 PFOS (ug/l) PFOS Breakthrough Results Influent Lead GAC 1 Lead Resin Lag GAC 0.1 Lag Resin 0.01 EPA PFOA+PFOS HA ,000 20,000 30,000 40,000 50, Amec Foster Wheeler Bed Volumes

22 PFOS breakthrough at 5-min EBCT

23 Amec Foster Wheeler Precursor

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25 Amec Foster Wheeler Carbons

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32 Volume Treated Before Breakthrough: All Observed PFAS 32 Amec Foster Wheeler 2016.

33 Total PFAS Concentration (ppb) Successful Regen at Pilot Scale 6.0 Total PFAS Concentration from Lead IX Media Bed Virgin Media Post Regen ,000 2,000 3,000 4,000 5,000 6,000 7,000 8, Amec Foster Wheeler Volume Treated (Bed Volumes)

34 Why is Ion Exchange so effective? Regeneration tells the story ion exchange and adsorption combined Ion exchange resin is a strong adsorbent with ion exchange functionality The resin has high affinity for PFOA (carboxylate head) and PFOS (sulfonate head). Over time, PFOA and PFOS replace other anions on the resin Regeneration with solvent-brine solution o o High concentration salt dislodges the anionic heads of PFAS molecules from the resin High concentration solvent desorbs the PFAS molecules from the resin IX Resin takes advantage of the unique properties of PFAS to both exchange ions and adsorb 34

35 Path Forward - 2 full-scale designs Aims 600 gpm

36 Path Forward - 2 full-scale designs Site gpm

37 Full Scale Application Lifecycle cost evaluation performed for full-scale 200 gpm system at Pease AFB (Site 8) Capital cost for Resin system is +/- 15% higher than GAC Media cost Regeneration system O&M cost is +/- 50% lower than GAC Resin has higher capacity No media replacement Even without regeneration (resin exchange program), lifecycle cost of resin system is lower, depending upon PFAS mix Two full-scale systems in detailed design Site 8: 200 gpm; AFFF source area AIMS Site: 600 gpm; up-gradient of Haven drinking water well Both systems scheduled to start up next Fall 37

38 Ongoing R&D Iron sequestration at Pease using pilot scale vessels Multiple regenerations for resin longevity testing Distillation optimization for spent regenerant solution Reduce in solvent use Reduce distillation time Alternative regeneration solutions Ammonium chloride Ammonium hydroxide Ethanol Various salt combination Alternative media testing Sorbix A3F compared to Other commercial IX media Carbonaceous GAC Coconut GAC 38 Amec Foster Wheeler 2016.

39 Market Opportunities for IX Drinking water applications UCMR3 data Municipal supply Point of use Pre-treatment or polish on GAC systems, and vice versa Single use / exchange or regeneration systems On-site regeneration Centralized regeneration Concentrated brine disposal In-Situ Applications 39 Amec Foster Wheeler 2016.

40 Questions? Nathan Hagelin Amec Foster Wheeler (207) Steve Woodard ECT2 (207) Thank you to our co-authors: Brandon Newman, Amec Foster Wheeler Mike Nickelsen, ECT2