Lawrence Livermore National Laboratory Environmental Restoration Division UCRL-PRES-207684

1. Remedial Strategy for Perchlorate-bearing Commingled Plumes at an Explosives Test FacilityEPA Technical Support Project MeetingOctober 21, 2004Speaker: Vic Madrid Lawrence Livermore National LaboratoryEnvironmental Restoration Division UCRL-PRES-207684 This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

2. Location Map Site 300 location map Site 300 Courtesy Kevin Mayer, US EPA, Region 9

3. High explosives RDX or cyclonite: C3 H6 N6 O6 HMX or octogen: C4 H8 N8 O8 Potassium perchlorate: KClO4 Ammonium perchlorate: NH4ClO4 Mock Explosives: Ba(NO3)2 Nitric acid: HNO3 Radionuclides Tritium: 3H Depleted uranium (235U/238U < 0.007) Solvents & heat exchange fluids TCE Silicon oil (TKEBS/TBOS) Site 300 Raw Chemicals

4. Open air detonation on firing table Raw Materials Test Device HE Processing Facility Device shipped offsite Floor drain Clarifier & Cloth Filter HE Solid Waste HE Liquid Waste Septic system Unlined lagoon Dry well Firing table gravel & shot debris disposed in unlined landfills Open burn treatment facility Site 300 Technical Operations

5. Raw Materials Test Device HE Processing Facility Device shipped offsite Floor drain Clarifier & Cloth Filter HE Solid Waste HE Liquid Waste Septic system Unlined lagoon Dry well Open burn treatment facility Site 300 Technical Operations Environmental Test Facility TCE used as heat exchange fluid

6. Data from CERCLA investigations 1,000+ boreholes ~ 70% continuously cored > 50% geophysical logs up to 550 ft depth 600+ ground water monitor wells 15 years of ground water monitoring data hydrographs covering drought to El Niño conditions broad range of chemical data including isotopes

7. Site 300’s commingled plumes 8 Operable Units 12 commingled plumes Low levels of perchlorate detected in nearly all plumes

8. Summary of perchlorate data From 1965 to 1975 about 2 tons of perchlorate were used at Site 300 Perchlorate monitoring began in January 1998 at the request of the RWQCB 2,520 ground water samples have been collected from 380 monitor wells and analyzed for perchlorate at 4 µg/L detection limit 730 perchlorate detections in 122 monitor wells Maximum result = 65 µg/L detected down gradient of a landfill pit The most widespread perchlorate contamination is located beneath the HE Process Area where it is commingled with VOCs, RDX, & elevated nitrate. In the northern part of Site 300 perchlorate is commingled with tritium, depleted uranium, and elevated nitrate.

9. Major geologic structures

10. Pit 7 complex – tritium plume

11. Extent of pit inundation by shallow ground water during 1998 El Niño Dec ‘97 Feb ‘98 Mar ‘98 Apr ‘98 May ‘98 Jul ‘98

12. Hydrogeologic Cross-section through the landfill pits Pit 5 Pit 7 Pit 7 Pit 5

13. Extent of depleted uranium in ground water Bedrock aquifer Pit 7 Pit 3 Pit 5 Alluvial aquifer

14. Perchlorate detections in Pit 7 area 11 8 14

15. Funnel & gate Hydraulic Diversion PRB Proposed remedial alternatives for perchlorate-bearing commingled plume ex situ Multi-component remedial alternatives to remove depleted uranium and perchlorate, prevent pit inundation, & recycle tritium 1) Hydraulic diversion system 2) In situ (PRB) using cow bone char or apetite & ion exchange resin 3) Ex situ (funnel & gate) using cow bone char or apetite & ion exchange resin 4) Recirculation of tritium-bearing effluent for ex-situ option in situ Draft Final Pit 7 Remedial Investigation/Feasibility for the Pit 7 Complex at Lawrence Livermore National Laboratory Site 300, December, 2004 UCRL-AR-202492-DR

16. A GW Elevation Contours B832 Cyn Recharge Recharge Extent of Saturation 650 Recharge HE Process Area 600 GSA Discharge to alluvial aquifer Unconfined Confined A’ 550 Tnbs2 Aquifer Conceptual Model

17. 0 1000 feet Tnbs2 TCE (µg/L) Mass Est. = 13 kg TCE source 50 40 20 10 5 30 TCEµg/L Former W-S Well 6 50 40 30 20 10 5

18. 0 1000 feet Tnbs2 RDX (µg/L) Mass Est. = 3 kg RDX source 45 50 25 5 5 25 50 90 45 10 TCEµg/L 1 RDXµg/L 75 100 50 50 25 25 5 5

19. 0 1000 feet Tnbs2 NO3- (mg/L) Mass Est. = 100,000 kg Possible nitrate source 90 60 45 10

20. 86 - >100 mg/L 65 - 85 mg/L 51 - 65 mg/L 31 - 50 mg/L 11 - 30 mg/L ND- 10 mg/L Nitrate (mg/L) along cross-section A-A’ 97 120 70 130 100 100 90 62 58 80 35 ND 15 12 ND 3.6

21. Dissolved O2 (mg/L) along cross-section A-A’ 4.6 4.1 7.6 5.8 < .2 0.3 7.2 0.8 1.4 0.2 1.0 1.1

22. 18O (per mil) Denitrification trend line Soil Septic waste 15N (per mil) Isotopic signatures of nitrate in groundwater and in potential source materials Harry R. Beller, Vic Madrid, G. Bryant Hudson, Walt W. McNab, and Tina Carlsen “Biogeochemistry and natural attenuation of nitrate in groundwater at an explosives test facility” Applied Geochemistry 19 (2004).

23. Nitrate equivalents (mg/L) Excess N2 along cross-section A-A’ Harry R. Beller, Vic Madrid, G. Bryant Hudson, Walt W. McNab, and Tina Carlsen “Biogeochemistry and natural attenuation of nitrate in groundwater at an explosives test facility” Applied Geochemistry 19 (2004).

24. Mass Est. = 7 kg ClO4 source 100 50 45 25 5 20 5 5 25 50 10 20 45 10 TCEµg/L TCEµg/L 1 CLO4-µg/L 100 75 20 50 50 0 1000 10 25 25 feet 5 5 5 Tnbs2 ClO4- (µg/L)

25. Perchlorate (µg/L) along cross-section A-A’ ND ND ND 9.2 8.7 11 5.7 ND 9.8 9.2 5.8 ND ND ND ND ND ND > 8 µg/L 4 - 8 ND < 4

26. Ongoing ground water cleanup activities Currently operating 13 ground water treatment facilities 7 facilities treating perchlorate 2 new facilities planned for FY’05 will treat perchlorate

27. Key question… Given large-scale, dilute, multiple constituent plumes in low-yield aquifers, how do we develop cost-effective strategies for ground water extraction and treatment using available remedial technology and effluent disposal options?

28. COC Destruction Removal • VOCs & RDXGAC • ClO4- & NO3- Bioreactor Ion exchange • Phytoremediation Treatment options

29. Method Advantage Disadvantage Air misting - nitrate utilization by - wetland creation indigenous grasses Subsurface - hydraulic control - maintenance Injection - preserve resource Surface- low cost - compliance issues Discharge- low maintenance Effluent disposal

30. Does GAC remove perchlorate? GAC_1 influent GAC_2 influent GAC_3 influent GAC_2 GAC_1 GAC_3 effluent W-817-03 ClO4- break through TCE = 14-29 µg/L RDX = 5-10 µg/L ClO4- = 17-33 µg/L NO3- = 70-90 mg/L W-817-03

31. GAC profiling results Treated 50,000 gallons @ 1-2 gpm flow rate using solar-powered GAC treatment unit ClO4- breakthrough after 20,000 gallons Effluent @ perchlorate breakthrough GAC Profile TCE = <0.5 µg/L < 0.5 µg/L RDX = <1.0 µg/L < 0.3 mg/kg ClO4- = 7.0 µg/L 47 µg/kg NO3-= 56 mg/L 178 mg/kg Sorption capacity of GAC for ClO4- based on this test = ~ 18 mg/kg or ~ 2 grams per 55 gallon drum of GAC

32. µg/L Perchlorate breakthrough GAC perchlorate removal data

33. Fixed film bioreactor Fixed-film bioreactor Designed to treat nitrate using denitrifying bacteria. Influent nitrate = 90 mg/L ( as NO3-) Flow rate = 1-2 gpm Effluent nitrate < 1 mg/L at peak efficiency 8-hr residence time Acetic acid used as main nutrient source. Minimizes nitrate loading on IX resin.

34. Low-cost, solar powered treatment train with containerized wetland (CW) Solar-powered treatment train consisting of GAC, CW, & IX operates 10 to 15 hrs / day depending on sun angle. CW uses local indigenous plants to remediate nitrate and perchlorate. Influent = 10 to 15 µg/L ClO4- & 45 mg/L NO3- Flow rate = 1 gpm CW Effluent = < 4 µg/L ClO4- & < 10 mg/L NO3- at peak efficiency 15-hour CW residence time Avoid creating wetland habitat. Ion exchange polishing used to ensure compliance with effluent discharge requirements.

35. GAC removal GAC removal CW removal CW removal IX polish Detection Limit B854-PRX Perchlorate Performance Data

36. Ion exchange Sybron SR-7: nitrate-specific ion exchange resin Higher affinity for perchlorate than nitrate (i.e., selectively removes perchlorate from nitrate-bearing water). Influent = 40µg/L ClO4- & 100 mg/L NO3- Flow rate = 3 gpm Effluent = < 4 µg/L ClO4- & 20 mg/L NO3- Perchlorate-laden resin is extremely difficult to regenerate, so it is disposed of as hazardous waste.

37. Bioreactor GAC IX ClO4- NO3- TCE, RDX, ClO4-, NO3- ClO4-NO3- NO3- GAC Bioreactor IX Commingled plume treatment train

38. B815-SRC Perchlorate Performance Data Replace IX resin µg/L IX polish Detection Limit

39. Extraction well field management priorities Prevent plumes from migrating offsite Contain source areas Cost efficiency Preserve resource

40. Capture zone analysis of extraction well field

41. Remedial Strategy Balance site boundary pumping with up gradient pumping. Hydraulically contain source areas. Minimize nitrate loading on IX resin to reduce waste disposal costs. Strategically inject treated effluent - reverse natural gradient at site boundary - flush source areas - preserve resource Demonstrate technical basis for MNA of nitrate.

42. Final well field design Extraction well 815-SRC Injection well 815-PRX 817-PRX 817-SRC 815-DSB

43. Acknowledgements Project Manager: Leslie Ferry Hydrogeology: Zafer Demir, Mike Taffet, & Walt McNab Analytical chemistry: Brad Esser, Bryant Hydson, & Jean Moran Microbiology: Harry Beller Environmental engineering: Rolf Halden*, Bill Daily Jr, & Matthew Verce Phytoremediation: Paula Krauter & Tina Carlsen * Johns Hopkins Bloomberg School of Public Health References for more information: Burge, Stephany and Rolf Halden, “Nitrate and Perchlorate Removal from Groundwater by Ion Exchange” UCRL-ID-135639, September 8, 1999. Paula Krauter, Bill Daily Jr., Valerie Dibley, Holly Pinkart, and Tina Legler. Perchlorate and Nitrate Remediation Efficiency and Microbial Diversity in a Containerized Wetland Bioreactor. Submitted to International J. of Phytoremediation June 17, 2004. UCRL-JRNL-204756. Harry R. Beller, Vic Madrid, G. Bryant Hudson, Walt W. McNab, and Tina Carlsen “Biogeochemistry and natural attenuation of nitrate in groundwater at an explosives test facility” Applied Geochemistry 19 (2004).