In-Situ Thermal Treatment of Fractured Rock

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1 In-Situ Thermal Treatment of Fractured Rock Ralph S. Baker, Ph.D. Chairman and Chief Scientist Gorm Heron, Ph.D. Chief Technology Officer TerraTherm, Inc.

2 About TerraTherm, Inc. TCH at a recently completed site in USEPA Reg. 2 TerraTherm, a US-based company, is the only thermal vendor offering all 3 of the major methods of subsurface heating, TCH, SEE and ERH/ET-DSP. At > 35 consecutive projects since 2002 on four continents, TerraTherm has met all remedial goals upon completion. 2

3 TerraTherm What We Do Sites with environmental liability and NAPL source zones Pioneer Midler Ave. Site, Syracuse, NY 3

4 Cleanup Standard (mg/kg) PCE < 5.60 TCE < 2.80 VC < 0.80 t-1,2-dce < 1.20 TVOC <10.40 ALL ACHIEVED Largest of the 3 Target Treatment Zones (TTZs) 11/28/2007 Home Improvement Store built adjacent to the TTZ 4

5 Contaminant Mass Removal Mass removal from thermal sites (by TerraTherm staff): >1,340,000 kg contaminants: Chlorinated solvents Creosote/PAHs Coal tar Oils PCBs Dioxins

6 Example Source Area DNAPL and VOC Distribution Fill Sand/silt Clay or Till Gravel/weathered rock aquifer, v>0.3 m/d (>1 ft/d) Fractured bedrock 6

7 Heating Methods Thermal Conduction Heating* (TCH)/In Situ Thermal Desorption* (ISTD) - Heating governed by thermal conductivity Comparison ElectroThermal-Dynamic Stripping Process * (ET-DSP )/Electrical Resistance Heating (ERH) - Heating governed by electrical conductivity Steam-Enhanced Extraction* (SEE) - Heating governed by hydraulic conductivity *Offered by TerraTherm 7

Applicability TCH* - Heating governed by thermal conductivity (f~3); Wide range of target temperatures; Low to moderate permeability settings Comparison ERH* - Heating governed by electrical

8 Applicability TCH* - Heating governed by thermal conductivity (f~3); Wide range of target temperatures; Low to moderate permeability settings Comparison ERH* - Heating governed by electrical conductivity (f~200); B.P. of water; Low to moderate permeability settings SEE* - Heating governed by hydraulic conductivity (f~10 6 ); B.P. of water; High permeability settings *Offered by TerraTherm, Inc. 8 8

9 Vapor Pressure vs. Temperature ERH, SEE, TCH TCH 500 Vapor Pressure (mm Hg) Temperature ( C) Vapor pressures increase exponentially during heating 9

10 TCE Volatilization, Pore Scale 700,000 ppm TCE possible in vapor phase in pore spaces near NAPL at >80 C 700,000 ppm TCE (LaChance 2014) 10

11 Applicable Technologies in Each Zone SEE/TCH/ ERH/ET-DSP Fill Sand/silt TCH/ERH/ET-DSP Clay or Till SEE TCH, ERH, ET-DSP? Gravel/weathered rock aquifer, v>0.3 m/d (>1 ft/d) Fractured bedrock 11

12 Challenge of Removing CVOCs from Fractured Rock COCs present in matrix Advection-Dispersion Mass In Fracture distribution: C T S = ρ Diffusion into Matrix g.w. velocity ( Kd b w a b ρ + φ + H ' φ )? Fracture-dominated flow Unknown maximum depth 12

13 Thermal in Rock Heat matrix and fractures to boiling temperatures Ensure steam capture and extraction co-located heating and extraction wells Match heating technology for matrix with rock properties Porosity, permeability Resistivity Ensure heating of fracture zones 13

14 SEE at Edwards AFB Site 61, CA Fractured granite (quartz monzonite) 14

15 SEE at Edwards AFB Site 61, CA 15

16 Edwards AFB Electrical Resistance Tomography (ERT) Data Planes during SEE VEA-4 VEA-2 VEA-5 VEA-3 VEA-1 It is difficult to heat fractured rock with steam alone 16

17 Is Resistivity Low Enough for ERH/ ET-DSP to be Applicable in Rock? 600 Volt limit for low voltage permits Typical applied voltages V Near surface step potential limitations (Health & Safety) For deep sites, can apply higher voltages Each site has a maximum voltage which can be safely used and permitted Most sites: 600 V Required soil resistivity: < 500 & m 17

18 Electrical Resistivity Palacky (1987) Implications: Solid bedrock in itself cannot be heated using ERH it is too resistive More porous rock need to be wet 18

TCH: Thermal Conduction Heating Applicable to Virtually All Rock Types 400 C 300 200

19 TCH: Thermal Conduction Heating Applicable to Virtually All Rock Types 400 C C 100 t 2 t 1 Heater Distance t 1,2 = temperature progression over time Heater 19

20 TCH in Fractured Rock Site, SC 20

21 Heater Well Vapor Collection Manifold Heater Vacuum Well 21

22 22

23 Conceptual Cross-Section Through Treatment Zone Fill/Saprolite 9 m (30 ft) Saprolite 17 m (55 ft) 27 m (90 ft) 23 m (75 ft) Weathered BR BR FRX Gneiss Treatment zone = 6,650 m 3 (8,700 cy) 23

24 Co-Located Heater+Vacuum Well Heater Well To off gas treatment Fill/Saprolite 9 m (30 ft) Saprolite 17 m (55 ft) 27 m (90 ft) 23 m (75 ft) Weathered BR BR FRX Gneiss Boosted grout 24

25 Temperature Profiles at Thermocouples T1 - T7 Heated Interval Depth - Ft Fill Saprolite Starting Temperature Profile Weathered Bedrock Temperature - F Boiling Point H 2 O 2/1/2007 T1 T2 T3 T4 T5 T6 T BR FRX Gneiss 25

26 Temperature Profiles at Thermocouples T1 - T7 Depth - Ft Fill Saprolite Temperature - F /27/2007 T1 T2 T3 T4 T5 T6 T7 60 Weathered Bedrock BR FRX Gneiss 26

Temperature Profiles at Thermocouples T1 - T7 Depth - Ft 0 10 20 30 40 50 Fill Saprolite Temperature - F 50 70

27 Temperature Profiles at Thermocouples T1 - T7 Depth - Ft Fill Saprolite Temperature - F /17/2007 T1 T2 T3 T4 T5 T6 T7 60 Weathered Bedrock BR FRX Gneiss 27

28 Temperature Profiles at Thermocouples T1 - T7 0 Temperature - F Depth - Ft Fill Saprolite 5/29/2007 T1 T2 T3 T4 T5 T6 T7 60 Weathered Bedrock BR FRX Gneiss 28

29 Mass Removal During TCH Treatment ~5,500 kg (~12,000 lbs) of TCE Removal Rate (lbs/hr) Total Removed (Tons) Days after Initial Startup (Jan 29, 2007) Removal Rate Total Removed 29

Confirmation Soil Data From TCH Project in SC µg/kg TCE 1 10 100 1,000 10,000 100,000 1,000,000

30 Confirmation Soil Data From TCH Project in SC µg/kg TCE ,000 10, ,000 1,000,000 10,000, ,000, ft bgs Location 1 Location Min. Soil Conc. For DNAPL foc: 0.05% - 0.1% n: Location 3 Location 4 Location 5 Location 6 56 Samples ND Cleanup Objective: 95% UCL of mean less than 60 µg.kg DNAPL 95% UCL of mean TCE conc. = 17 µg/kg Max Pre-Treatment 30

31 Summary, SC Case Study Rock heats even easier than overburden (less water and porosity) Extremely low post-tch concentrations TCH effective in heating and treating DNAPL in crystalline rock 31

$fractures ESTCP Project$

32 Data Needs: Collection and Analysis of Rock Samples Ascertain pre- vs. post-thermal COCs in rock matrix, with distance from fractures ESTCP Project ER200715, NAWC, E. Trenton, NJ 32

33 Queens Univ. Rock Crusher (Kueper et al.) 33

34 TCH at SRSNE Superfund Site, Southington, CT 0.7 ha (1.7 acres) 36,000 m3 (47,000 cy) Overburden and upper 1.5 m (5 ft) of fractured rock, in operation Co-Located heater and vacuum extraction borings 34

Conclusions Fractured rock sites are very different

$fractured rock Use TCH in combination with SEE when$ necessary (high groundwater flux) ERH may also work

35 Conclusions Fractured rock sites are very different Select thermal technology based on site conditions TCH is the most reliable technology for heating fractured rock Use TCH in combination with SEE when necessary (high groundwater flux) ERH may also work in wet porous rock Ensure that vapors are captured 35

References Questions? Heron, G., R.S. Baker, J.M. Bierschenk and J. LaChance. 2008. Use of Thermal Conduction Heating for the Remediation of DNAPL in Fractured Bedrock. Paper P-003, in: Bruce M.

36 References Questions? Heron, G., R.S. Baker, J.M. Bierschenk and J. LaChance Use of Thermal Conduction Heating for the Remediation of DNAPL in Fractured Bedrock. Paper P-003, in: Bruce M. Sass (Conference Chair), Remediation of Chlorinated and Recalcitrant Compounds Proceedings of the Sixth International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2008). Battelle Press, Columbus, OH. Lebrón, C U.S. Navy Demonstrates Thermal Conductive heating for DNAPL Removal in Fractured Rock. USEPA Technology News & Trends (December, 2010). NAVFAC ESTCP Final Report: Dense Non Aqueous Phase Liquid (DNAPL) Removal from Fractured Rock Using Thermal Conductive Heating (TCH). Prepared by C. Lebrón, D. Phelan, G. Heron, J. LaChance, S.G. Nielsen, B. Kueper, D. Rodreguez, A. Wemp, D. Baston, P. LaCombe and F.H. Chapelle. Contract Report CR-NAVFAC ESC-EV-1202, Port Hueneme, CA. 36

ENVIRONMENTAL RESTORATION

ENVIRONMENTAL RESTORATION Site Characterization and Remediation in Fractured Rock Introduction Site characterization and remediation in fractured rock affords a unique set of challenges not typically associated