Emerging Contaminants and Treatment Technologies, Including PFAS, 1,4-dioxane and TCP. Steve Woodard, Ph.D., P.E.

Transcription

1 Emerging Contaminants and Treatment Technologies, Including PFAS, 1,4-dioxane and TCP Steve Woodard, Ph.D., P.E.

2 Presentation outline A primer on emerging contaminants PFAS: increasing global interest/pressure to clean up Treatment technologies How ion exchange resin work and how does it get installed? 1,4-dioxane: a special challenge 1,2,3-Trichloropropane Summary

3 What are the emerging contaminants? PFAS (formerly PFCs) 1,4-dioxane 1,2,3-Trichloropropane (TCP) N-Nitrosodimethylamine suspected human carcinogen Pharmaceuticals and personal care products Tungsten - Linked with leukemia Tributyltin - wood preservative, biocide in certain paints Ethylene dibromide - pesticide, fumigant Hex chrome carcinogen, taking another look and dropping levels

4 Focus on the top three PFAS 1,4-dioxane 1,2,3-Trichloropropane

5 PFAS: The emerging contaminant in the headlines

6 PFAS sources, regulation & treatment challenges Sources of PFAS include firefighting foam, Teflon TM, Scotchgard TM, Gore-Tex, etc. 70 ppt is roughly equivalent to 1 person in 2 world populations New PFAS compounds are being discovered continually Toxicology is uncertain/developing Carbon-fluorine bond is one of strongest in nature

7 PFAS treatment options Biological Treatment Air Stripping GAC $$ Ion Exchange (IEX) Resin Reverse Osmosis Advanced Oxidation

8 How does IEX resin remove PFAS? Regenerable IEX Resin Sorbix A3F

9 Dual mechanism of removal: IEX and adsorption PFOS Molecule Simplified Resin Bead

10 How are the IEX treatment systems installed?

11 Resin vessels and centralized (proprietary) regen system

12 Public outcry is driving action

13 C-17 transport plane is delivering interim treatment systems to Australia

14 Case study: What happened at New England Air Base? Community of roughly 21,000 PFOA and PFOS detected in public drinking water supply PFAS tied to health impacts; citizens become concerned Contamination originated from firefighting foam use at the AFB

15 Pilot test: IEX resin vs. GAC 15 Amec Foster Wheeler Process pumps GAC (front) and resin (rear) vessels Cartridge filters for solids removal

16 PFOA breakthrough at 5-min EBCT GAC Resin

17 PFOS breakthrough at 5-min EBCT GAC Resin

18 Very promising results for alternative resins: Resin A = Sorbix A3F

19 Residuals management: successful destruction of PFAS compounds (on site) PFAS removal from regen still bottoms using plasma treatment

20 What are the significant technology benefits? Dual mechanism of removal takes advantage of unique properties of PFAS compounds Capacity is 5-6X greater than GAC for PFOA and > 8-10X greater for PFOS. Kinetics are faster, too, allowing use of smaller vessels Resin can be regenerated in place using proprietary process Distillation, ultra concentration and PFAS destruction maximize sustainability Central regen and installation in shipping containers: compact, rapidly-deployable, mobile, cost-effective PFAS treatment process New resins are being tested successfully: e.g., effective removal of shorter chain compounds

21 1,4-dioxane Stabilizer for chlorinated solvents, e.g. 1,1,1-TCA Wetting agent for polyester and paper processing Residue in cosmetics, shampoos, automotive coolants, fumigants

22 Representative US Regs/G uida nce 1Notes New Hampshire 0.25 Reporting limit for all public water supplies Massachusetts 0.3 Groundwater cleanup standard New Jersey 0.4 Groundwater Quality Standard- October 2015 CaHfornia 1 Notification level Florida 3.2 Minimum criteria Colorado 3.2 Drinking Water standard (proposed 0.35) lij inois 7.7 Texas 9.1 New York 50 South Carolina 70 Michigan 85 Non- TACO (Tiered Approach to Corrective Action) Chemical Resident iai Protective Concentration Level Drinking water standard Drinking water health advisory Cleanup criteria and screening level E EGING 0 I T S U MM l I

23 Why is 1,4-dioxane such a challenge to treat? Miscible in water Low volatility, low sorption Difficult to measure Difficult to remediate (recalcitrant) Travels rapidly in subsurface; plume often extends beyond extraction wells Once discovered, often the driver for cleanup

24 Challenges with existing 1,4-D pump & treat technologies (AOP) Struggle with variable influent loadings Delivery, storage and consumption of regulated chemicals (e.g. H 2 O 2 ) Frequent change-out of UV lamps Bromate and hex chrome formation potential TSS/turbidity/TDS reduces effectiveness Subject to free radical scavengers O&M intensive

25 Ambersorb treatment system

26 Waltham, MA installation influent and effluent 1,4-dioxane

27 St. Petersburg, FL installation A unique approach to iron management Phase 2: Long-term plume control Design basis: Flow = gpm 1,4-dioxane = 2,535 ppb Total organics = 17,450 ppb Iron = 6-30 mg/l

28 Iron sludge dewatering Iron sludge Plate and frame filter press

29 Oxidation state matters Ferrous iron Ferric iron Since Ambersorb does not oxidize incoming iron, we were able to shut down the iron pretreatment system, resulting on greatly reduced O&M cost and hassle

30 1,2,3-TCP Point sources: industry, defense Solvent/degreaser Cross-linking agent in polymer production Impurity in pesticides Recalcitrant and highly mobile No federal MCL yet CDPH (CA) Recognized as human carcinogen Notification level of 5 ppt; public health goal of 0.7 ppt

31 1,2,3-TCP treatment options Ambersrb Chemical Oxidation GAC Chemical Reduction Ambersorb Zero Valent Iron

32 Emerging contaminants summary Toxic: probable/possible human carcinogens No MCLs (federal drinking water limits) set by EPA yet Persistent/recalcitrant Challenging to treat Synthetic media (resins) hold significant promise Adsorption and ion exchange are simple processes Resins are regenerable on site Exciting R&D, demonstrations and full-scale treatment system performance

33 Thank you! Steve Woodard (207) NEXT