PFAS TREATMENT AND REMEDIATION WEBINAR: TREATMENT OPTIONS FOR SOIL & GROUNDWATER

Transcription

1 PFAS TREATMENT AND REMEDIATION WEBINAR: TREATMENT OPTIONS FOR SOIL & GROUNDWATER MICHELLE CRIMI, PH.D. ASSOCIATE PROFESSOR, INSTITUTE FOR A SUSTAINABLE ENVIRONMENT, CLARKSON UNIVERSITY DECEMBER 14, 2016 OBJECTIVES: Summarize the challenges associated with treatment of PFAS-contaminated soil and groundwater Describe potential viable PFAS remediation approaches

2 INTRODUCTION Perfluorinated Compounds Perfluorinated alkyl acids (PFAAs) PFOA PFOS PFBS PFBA PFHxA PFHxS Intermediates or Precursors N-MeFOSE N-EtFOSE 6:2 FTS Guidelines (ng/l) PHA MN NJ NC PFOA PFOS n/a n/a EPA (2016) 70

3 INTRODUCTION PFOA PFOS C Aqueous Formula Vapor Pressure Log K Solubility oc Degradation 0.1 kpa (20 C) 4.1 g/l (22 C) PFOA C 8 HF 15 O Stable 10 mm Hg (25 C) 9.5 g/l (25 C) PFOS C 8 F 17 SO x 10 4 Pa at 20 C 570 mg/l 2.57 Stable PFHxS C 6 F 13 SO Pa (25 C) ES 6.2 mg/l ES 22 mg/l ES 3.5 ES Stable PFBS C 4 F 9 SO mm Hg at 20 C 6:2 FTS F(CF 2 ) 6 CH 2 CH 2 SO Pa(25 C) ES mm Hg (25 C) ES 8900 mg/l ES 344mg/L ES ES = estimated from EPISuite (U.S. EPA ES 1.9 ES Stable 11 mg/les 2mg/L ES 4.0 ES Biodegradable under specific conditions

4 CHALLENGES Broad mixture Can t even detect/quantify some of these Range of properties with chain length and function group(s) hydrophobicity, reactivity Hydrophobic and electrostatic effects Anionic PFAAs Cationic or zwitterionic PFAS Precursors Compounds of concern Recalcitrant Strong C-F bond Low volatility High solubility Long plumes

5 REMEDIATION OPTIONS Excavation Incineration Expensive Contaminants must be treated off site Immobilization/Stabilization RemBind Powdered reagent added directly to soil matcare Filtration Modified clay Nanofiltration Reverse Osmosis TREATMENT TRAINS and COMBINED REMEDIES! Sorption Granular Activated Carbon (GAC) Carbon nanotubes Biomaterials Ion Exchange Resins Mineral materials (e.g., zeolites) Polymers Chemical treatment Chemical oxidation single oxidant and oxidant mixtures Electrochemical, sonochemical, and photochemical Plasma Customized reductants

6 SORPTION BY GAC

7 SORPTION GAC SERDP ER-2423

8 No cont. Kerosene TCE Ethanol No cont. Kerosene TCE Ethanol Maximum Loading (mg/g) Extent of Sorption(mg/g) Extent of Sorption (mg/g) SORPTION GAC Low PFC Conc (1 mg/l) Low PFC Conc Mix (1 mg/l) PFOA PFOS PFOA PFOS F400 Carbon and PFC Type Coconut PFOA-T4 PFOS-T PFOA-T4 PFOS-T4 Sorption under site-specific conditions

9 ION EXCHANGE

10

11 Courtesy of Nathan Hagelin, Amec Foster Wheeler and Steve Woodard, ECT 2

12 Courtesy of Nathan Hagelin, Amec Foster Wheeler and Steve Woodard, ECT 2 BLACK = Lead GAC YELLOW = Lag GAC GREEN = Lead Resin PURPLE = Lag Resin

13 CHEMICAL TREATMENT Activated Persulfate Electrochemical Chemical Reduction Plasma Combinations

14 Oxidation Approach Persulfate Intermediates and Byproducts F -, PFPrA, PFHpA, PFHxA, PFPA PFPeA, PFBA,TFA Permanganate F -, SO 2-4 UV-Fenton F -, Formic acid, PFPrA, PFHpA, PFHeA, PFPeA, PFBA Fe(III) F -, PFPrA, PFHpA, PFHeA, PFPeA Ferrates No observed F - Fe(III) and Oxalate F -, PFPrA, PFBA, PFPeA, PFHxA, PFHpA Catalyzed H 2 O 2 N/A Plasma F -, TFA PFPrA, PFBA, PFPeA, PFHxA, PFHpA, PFBS UV-Pb-modified TiO 2 PFHpA, PFHeA, PFPrA, TFA PFPeA, PFBA Sonolysis PFHpA, PFHxA, PFPA, TFA and F,PFHpS, PFHxS, PFOA Photocatalysis with Inidium oxide F -,PFHpA, PFHeA, PFPrA, PFPeA, PFBA TiO 2 photocatalysis PFHpA, PFHpA, PFPeA, PFBA Environmental photolysis PFBA, PFBS, PFOA Electrochemical oxidation F -, TFA, PFPA, PFBA, PFPeA, PFHxA, PFHpA Photolysis with persulfate F -,CO 2, SO 2-4 PFBA, PFPeA, PFHxA, PFHpA Microwave hydrothermal decomp. F -,CO 2, PFBA, PFPeA, PFHxA, PFHpA, PFHeA

15 Reduction Approach Intermediates and Byproducts Mg-aminoclay coated nanoscale ZVI F - Sub critical elemental iron F SO 2-4, CF 3 H, CO 2 UV-KI F -, formic acid, acetic acid, PFCAs (C1 C6). CF 3 H, C 2 F 6 UV photolysis of alkaline 2-propanol F SO 2-4 CF 4, C 2 F 6, C 3 F 8, C 7 F 16 Vitamin B 12 with Ti(III)-citrate Photocatalysis with B-Ga 2 O 3 F F -, PFPrA, PFHpA, PFHxA, PFPA PFPeA, PFBA,TFA

16 ACTIVATED PERSULFATE 50 ml polypropylene centrifuge 50 ml polypropylene centrifuge PFOA and PFOS solution PFOA and PFOS sorbed GAC Powder sodium persulfate Powder sodium persulfate Single dose doe =10 g/l Multiple dose = 2g/L 5 Single dose =10 g/l Multiple dose = 2g/L 5 Heat activation - Hot water bath 80ºC Aqueous Heat activation - Hot water bath 80ºC Sorbed

17 ACTIVATED PERSULFATE AQUEOUS PHASE

18 ACTIVATED PERSULFATE SORBED

19 Courtesy of Linda Lee, Professor, Purdue University

20 Courtesy of Charles Schaefer, Principal, CDM Smith

21 PFOS reduction by synthesized activated carbon (AC)-supported nano-bimetals Synthesis Reduce: FeCl 2 + ACNaBH 4 Catalysts: NiCl Fe 0 2 Coating 2 wt% NiFe 0 -AC PFOS mass removal Inorganic metabolites (F - & SO 4 2- ) Courtesy of Linda Lee, Professor, Purdue University Sulfate Oxidation state pre/post reaction Oxygen Matrix NiFe-AC Four extractions are performed using acidified methanol Particle Characterization 3 ppm PFOS solution is mixed with NiFe 0 - AC at 60 o C for 5 d PFOS Fully Extractable Pure PFOS F1s= Fluoride Iron Metal Oxide (NiFe-AC) Metal Carbonates (Matrix) Fe 3+ satellite PFOS remaining after NiFe-AC reaction PRIOR to extractions Organic metabolites Myers et al Mass (F/Hscale) = mass IUPAC scale x F Mass defect = Hscale mass F/H scale nominal mass (rounded down, F/H scale) Magnetite, Fe 3 O 4 (NiFe-AC) Ferric oxide, F 2 O 3 (Matrix) Nickel Ni(III) oxide, Ni 2 O 3 (NiFe-AC) No detected in the NP only matrix No PFOS on NiFe AFTER extractions Zenobio and Lee (2016) SERDP-ER-2426

22 Courtesy of Linda Lee, Professor, Purdue University

23 Courtesy of Linda Lee, Professor, Purdue University

24 G. R. Stratton, F. Dai, C. L. Bellona, T. M. Holsen, E. R. V. Dickenson and S. Mededovic Thagard, Plasma-based water treatment: Demonstration of efficient perfluorooctanoic acid (PFOA) degradation and identification of key reactants Environmental Science & Technology, 2016, accepted. Courtesy of Selma Mededovic Thagard, Clarkson University

25 Scaled-up enhanced contact plasma reactor 40 cm Treatment of contaminated groundwater (naval research site, Warminster, PA) Solid-phase extraction 40 cm Compound C 0 min (µg/l) C 60 min (µg/l) Removal (%) Treatment efficiency is 15 times greater than in the bench-scale reactor. The overall treatment efficiency is significantly higher compared to leading alternative treatment technologies. Perfluorooctanoic acid (PFOA)* Perfluorooctane sulfonate (PFOS)* Perfluoroheptanoic acid (PFHpA) Perfluorohexane sulfonate (PFHxS) Perfluorohexanoic acid (PFHxA) Perfluoropentanoic acid (PFPnA) PFOA & PFOS concentration was reduced by at least 75% within one minute of treatment Courtesy of Selma Mededovic Thagard, Clarkson University

26 OXIDANT COMBINATIONS ScisoR ARCADIS OxyZone - EnChem

27 H4PFOS C7A SCISOR C7S C8A Blanco SC2-1 SC2-2 SC2-3 SC2-4 C7S C8A C4S C5A C4A C6A C6S C8S C7A H4PFOS C4S C5A C4A C6A C6S C8S ScisoR Smart Combined In Situ Oxidation and Reduction Developed, tested and patented and by ARCADIS NL lead by Tessa Pancras Initial lab test have show removal of PFAS Effective at ambient temperature Soluble reagents can be injected or mixed with impacted soil and groundwater Comprises a specifically activated persulfate Courtesy of Ian Ross, Arcadis Potential for in situ / on site remediation of PFAS

28 Concentration (ng/l) RESULTS: PEROXIDE ACTIVATED PERSULFATE SOIL AND GROUNDWATER 300 g soil, 300 ml groundwater PFAS monitored in reactor supernatant C7S C8A C4S C5A C4A C6A C6S C8S C7A Blanco 0 SC2-1 H4PFOS SC2-2 Blanco SC2-3 SC1-1 SC2-4 SC1-2 SC1-3 SC1-4 SC1-5 H4PFOS C7A H4PFOS C7S C7A C8A C7S C4S C8A C5A C4S C4A C5A C6A C4A C6S C6A C8S C6S C8S Courtesy of Ian Ross, Arcadis

29 Concentration (ng/l) RESULTS: SCISOR SOIL AND GROUNDWATER 300 g soil, 300 ml groundwater PFAS monitored in reactor supernatant Blanco 0 SC2-1 SC2-2 SC2-3 Blanco SC2-1 SC2-4 SC2-2 SC2-3 SC2-4 C7S C8A C4S C5A C4A C7A H4PFOS C7S C8A C7A H4PFOS C6A C6S C8S C4S C5A C4A C6A C6S C8S H4PFOS C7A C7S C8A C4S C5A C4A C6A C6S C8S H4PFOS C7A C7S C8A C4S C5A C4A C6A C6S C8S Courtesy of Ian Ross, Arcadis

30 Contacts Ian Ross Ph.D. Global PFAS Lead Arcadis UK Jeff Burdick North America PFAS Lead Arcadis US Tessa Pancras European PFAS Lead Arcadis NL Download at: and-effects-of-poly-and-perfluoroalkyl-substances-pfas-report-no Courtesy of Ian Ross, Arcadis

31 CHALLENGES AND LIMITATIONS Mixtures, precursors, co-contaminants Incomplete mineralization Managing materials Energy intensity Technical challenges to in situ treatment Limited field-scale examples