1. Overview of Remedial Approaches at Superfund Fractured Bedrock Sites Edward Gilbert, CPG Technology Assessment Branch Technology Innovation and Field Services Division Office of Superfund Remediation & Technology Innovation

2. 1 Remedial Technologies Groundwater extraction and treatment (P&T) In situ Chemical Oxidation (ISCO) / Reduction (ISCR) Enhanced In Situ Bioremediation –Biostimulation –Bioaugmentation In Situ Thermal –Electrical Resistance Heating (ERH) –Thermal Conductive Heating (TCH) –Gas Thermal Remediation (GTR) –Steam Enhanced Extraction (SEE) –Radio Frequency Heating (RF) Monitored Natural Attenuation (MNA) January 14, 20141

3. 2 Contaminants of Concern VOCs SVOCs/PAHs Metals Pesticides/PCBs Dioxins/Dibenzofurans Radionuclides January 14, 20142

4. 3 Frac Rock Site Decision Documents Data mining of CERCLIS –FY2000 – 2012 (partial) RODs, ESDs, or Amended RODs –Queried text for any mention of fractured bedrock Groundwater Remedies 76 Sites 87 Operable Units in fractured bedrock DNAPL Remedies 7 Sites 7 Operable Units in fractured bedrock January 14, 20143

5. 4 Groundwater at Fractured Bedrock Sites Selected Remedies at 87 OUs –30 GW Extraction (including multiphase extraction) –16 Bioremediation –13 Oxidation (ISCO) – 3 Reactive Walls – 2 Chemical Reduction (ISCR) –36 No Action; deed restrictions; groundwater use/well drilling regulation; zoning regulation; covenants; monitoring; natural attenuation; MNA; etc. January 14, 20144

6. 5 NAPL at Fractured Bedrock Sites Selected Remedies at 7 Sites –5 Free Product Recovery –1 Bioremediation (oxygen addition) –2 ISCO –1 Vapor Extraction –1 ERH –1 Non-fundamental change (ESD) January 14, 20145

7. 6 CLU-IN’s Fractured Bedrock Project Profiles http://clu-in.org/products/fracrock/ http://clu-in.org/products/fracrock/ 248 profiles submitted –114 GW Pump and Treat Plus 13 Multi Phase Extraction –67 Bioremediation –55 Chemical Oxidation (in situ) –25 ‘Soil’ Vapor Extraction – 9 Thermal Treatment (in situ) – 5 Flushing (in situ) January 14, 20146

8. 7 CERCLIS January 14, 20147 CLU-IN

9. 8 Region 2 Sites 31 Sites with contaminated gw in fractured rock –21 ROD –10 Pre-ROD Selected remedies at 19 sites – 9 P&T (+ 1 possible) – 4 Enhanced bio (+ 1 possible) – 2 ISCO (+ 1 possible) – 3 MNA – 1 Leachate collection for containment – 4 TI Waivers January 14, 20148

10. 9 Karst Very difficult to characterize adequately –Conduits –Very high and turbulent groundwater flow velocities –Extreme heterogeneity –Dual-porosity and dual-permeability regimes –Sediment transport RODs for 71 sites –53% no active groundwater remedy –37% pump and treat –21% some form of in-situ remediation technology January 14, 20149

11. 10 Remedial Effectiveness? Jury is still out… –Shift from P&T to other technologies A method to track remedy progress/success? Need for fractured bedrock site database –CERCLIS –SEMS –Clu-In January 14, 201410

12. 11 Technical Impracticability Waivers* 91 waivers at 85 sites; FY88-FY11 85 waivers applied to groundwater –Complex geology cited as a contributing factor in the rationale for 54 of the 85 waivers Fractured bedrock Karst Heterogeneous soils with low permeability –VOCs, metals, SVOCs and PAHs January 14, 201411 * Summary of Technical Impracticability Waivers at National Priorities List Sites, EPA 2012

13. 12 Technical Impracticability Waivers* In light of the continuing scientific advances in groundwater remediation technologies which continue to evolve, regions should not be limited by previously-approved TI waivers described in this technical report as justification for what may be appropriate when evaluating and documenting current or future TI waivers. January 14, 201412 * Summary of Technical Impracticability Waivers at National Priorities List Sites, EPA 2012

14. 13 Future? In Situ Thermal Enhanced In Situ Bioremediation* ISCO/ISCR* Combined remedies/treatment trains Continued use of P&T for control/containment MNA * Fracking - Increased distribution/delivery January 14, 201413