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Case Study: Permanganate Applied to VOCs in Fractured Shale Beth L. Parker, Ph.D. Department of Earth Sciences University of Waterloo Presented at the EPA Symposium in Chicago December 12, 2002 1
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2 Research Collaborators l Dr. Tom Al –University of New Brunswick l Dr. Ulrich Mayer –University of British Columbia l Drs. Ramon Aravena and John Cherry –University of Waterloo l Kenneth Goldstein, CGWP –Malcolm Pirnie, Inc l Grant Anderson, P.G. –U.S. Army Corps of Engineers
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3 Watervliet Arsenal in New York State Watervliet Arsenal Troy Hudson River Shale
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4 Hudson River Watervliet Arsenal Building 40 Area
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Flow Overburden Bedrock PCE adapted from Mackay and Cherry, 1989 DNAPL DNAPL Passed Through Overburden Into Shale 5
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6 The Problem l Chlorinated ethenes – as high as 150 mg/L l Contamination down to 150 ft. bgs l All VOC mass in fractured shale l AOC is 200 ft west of Hudson River
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7 Study Area AW-MW-59 AW-MW-68 N Building 40
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8 Identification of Major Transmissive Zones Using Hydro-geophysics USGS, 2001
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9 Major Transmissive Zone Identified USGS, 2001
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93,600 5,310 5,150 16 MW-71 Fractures, Transmissive Zones, and PACKER TESTING Total VOCs from PACKER TESTING Leakage g/L USGS, 2001 10
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PCE and Degradation Products in Shale South North From packer test intervals during drilling PCE DCE 11
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12 Interconnected Fracture Network with Two Major Transmissive Zones 1 2 1 2 Cross-section view
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13 DNAPL was Initially Distributed in Many Fractures
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ILLUSTRATION OF MATRIX POROSITY A Microscopic view of rock matrix mineral particle DETAIL A 14
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15 DNAPL Phase Initially Resides within Fractures Fracture Aperture 2b Fracture Spacing H O 2 f m DNAPL Matrix porosity is 1000 times greater than fracture porosity
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16 DNAPL Disappearance by Diffusion Parker et al. (1994) Fracture Aperture 2b Fracture Spacing f m H O 2 DNAPL f m Dissolved Phase f m Dissolved Phase Early IntermediateLater Time
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17 Snake Hill Shale Formation Watervliet Site
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Core Hole In Source Zone B.L. Parker, 2000 18
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Diffusion Into Rock Matrix 19
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Core Sampling for Migration Pathway Identification B.L. Parker, 2000 20
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Core Diameter 3.2 Inches Sample Length ~Two Inches Overview of the Rock Core Method Parker and Colleagues 1997 21
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22 Two Rock Crushers Rock Crusher Crushing Cell 22
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MW-74 Dec. 2001 (preliminary data) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 0.010.1110100100010000 0 1E+06 conc. VOC (ug/L) depth (ft) PCE TCE c-DCE PCE solubility (240 mg/L) Rock Core Profile Dec 2001 Pre-KMnO 4 Injection CMT Aqueous PORTS Concentrations (Feb. 2002) 1 2 3 4 5 6 PCE – 8 ug/L TCE – 5 ug/L c-DCE – 350 ug/L PCE – 4 ug/L TCE – ND c-DCE – 1088 ug/L PCE – 458 ug/L TCE – 123 ug/L c-DCE – 2802 ug/L PCE – 9183 ug/L TCE – 382 ug/L c-DCE – 524 ug/L PCE – 13,988 ug/L TCE – 3,699 ug/L c-DCE – 15,155 ug/L PCE – 172 ug/L TCE – 259ug/L c-DCE – 11,745 ug/L 23
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24 WESTBAY ® MP SYSTEM 2.5 ft. Tripod Cable Reel Pressure Probe Sample Bottle 24
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25 SOLINST CMT ® SYSTEM 25
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26 Site Conceptual Model l VOC migration occurs in a large number of interconnected fractures l Nearly all VOC mass resides in the rock matrix rather than in the fractures
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It is well established that permanganate completely destroys chlorinated ethenes However, to do so, it must be delivered to the contaminant mass 27
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Can permanganate be effective for remediating chlorinated ethenes in fractured sedimentary rock? Important factors: l Delivery throughout fracture network l Diffusion rates into rock matrix l Oxidant Demand of Shale 28
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29 KMnO 4 Injections at Watervliet
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71 74 Potassium Permanganate Injection 59 76 75 65 34 ~145 feet bgs Phase 1 injection Phase 2 injection 30
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31 PILOT STUDY RESULTS in 2002 31
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32 Treatment Approach Permanganate Permanganate oxidizes chlorinated ethenes Solvent + MnO 4 - MnO 2 (s) + Cl - + Acid 13 C / 12 C and Chloride used to confirm destruction Stable chemistry in subsurface allows time for diffusion into matrix
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33 Remediation in Fractured Porous Media Treatment zone Early Time Later Time KMnO 4 in fracture Contaminated clay/rock B.L. Parker, 1993
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34 In Situ Oxidation in Fractured Porous Media Diffusion of both reactants occurs in opposite directions Readily destroys sorbed phase contaminants Greatly reduces time scale for remediation B.L. Parker, 1993
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35 Analogy to Fractured Shale Results from Permanganate Field Tests in Marine Clay
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Oxidized zone shows extent of diffusion invasion and treatment by KMnO 4 B.L. Parker, 1996 Invasion front Top of clay 36
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37 KMnO 4 Profile in Clay
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38 Combined Profiles in Clay Reaction interface
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39 Snake Hill Shale Formation Watervliet Site
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40 Permanganate Diffusion into Matrix from Fracture z x y diffusion 2b = fracture aperture mass x x + C/C o
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Elemental Manganese Profiles in Shale Transects Normal to Fractures Propagating in from Surface of Rock Sample Shale sample in 10 g/L KMnO 4 solution for ~6 weeks 41
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42 How long will MnO 4 take to remediate the source zone? l Answer being sought using ~field data ~laboratory tests ~numerical models
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Preliminary MIN3P Simulations Watervliet Arsenal 3D multicomponent reactive transport model Model developed by Dr. Ulrich Mayer (1999) Now being modified for permanganate oxidation 43
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44 MIN3P Simulation Simulate 1D MnO 4 - invasion into shale matrix where PCE has been diffusing in for 40 years to examine rates of matrix clean-up Parameters: Site-specific , D e, f oc MnO 4 - R = 1 PCE R = 220 (estimated using f oc =0.5%) Source [ PCE ] = 150 mg/L for 40 years Injection [ KMnO 4 ] = 5 g/L
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Chloride Diffusion Test Cell for Rock Golder Associates, Toronto 45
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46 Initial Condition 40 years PCE Diffusion-In MIN3P Model – Snake Hill Shale
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47 Matrix Profiles after 1 year MnO 4 - Injection MIN3P Model – Snake Hill Shale
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48 Matrix Profiles after 2 years MnO 4 - Injection MIN3P Model – Snake Hill Shale
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49 Matrix Profiles after 5 years MnO 4 - Injection MIN3P Model – Snake Hill Shale
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50 Partial Mass Destruction Greatly diminishes VOC mass flux into fracture network after permanganate is gone
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PCE flux to fracture after partial permanganate treatment Frac3DVS Modeling Log - Log Scale No MnO 4 Case 51
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52 Preliminary Conclusions Permanganate… Diffuses and reacts in low K matrix Prevents release of mass from matrix to flowing groundwater while present in fractures Greatly reduces magnitude of flux from matrix even after partial treatment
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53 How do we know that VOCs are being destroyed ? l Chloride increases at many locations l Change in carbon isotope ratio of PCE
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54 ON-GOING WORK l Rebound monitoring after pilot injections l Permanganate invasion tests –Laboratory samples –Field cores l Reactive transport modeling –Single fractures and fracture networks l Design of full-scale system and monitoring
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55 Acknowledgements l Project Contributors: ~Steven Chapman and Martin Guilbeault (UWaterloo) ~Daria Navon and Andrew Vitolins (Malcolm Pirnie) ~Stephen Wood (U.S. Army Corps of Engineers) ~JoAnn Kellogg (Watervliet Arsenal) ~John Williams and Fred Paillet (U.S.G.S) l Funding: ~U.S. Army Corps of Engineers ~Solvents-In-Groundwater Research Program
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56 The End
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