U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

For more information on Fractured Bedrock, please contact:

Ed Gilbert
Technology Integration and Information Branch

PH: (703) 603-8883 | Email: gilbert.edward@epa.gov



Fractured Rock

Remediation

Remediation of fractured bedrock is complicated by the difficulty in characterizing the flow system, the potential for small aperture fractures that restrict flow, dead end fractures that become contaminant sinks, and for some rock systems, primary porosity that allows diffusion into the rock matrix. For these reasons, most CERCLA and RCRA sites that have bedrock contamination use a pump-and-treat containment strategy that does not rely on detailed knowledge of contaminant location.

In more recent years, however, in situ techniques, such as bioremediation, chemical oxidation, chemical reduction, and thermal treatment, have been used with some success. With the exception of thermal treatment, these technologies rely on direct contact with the dissolved contaminants and hence need a thoroughly characterized site.

These technologies can often be combined to provide a more efficient cleanup. For example, at a manufacturing plant in northern New Jersey a pump and treat system was initially instituted for containment of a PCE plume. The facility decided that a biobarrier might be as effective and less expensive to operate for plume containment. Molasses was injected across the path of the plume into two lines of wells at the property boundary. The injections resulted in a very reduced aquifer zone and near complete reductive dechlorination of the dissolved PCE. The pump and treat system was subsequently deactivated, while periodic injections of molasses continues. Molasses also was used to reduce the contaminant flux from the source area, which contained DNAPL. After observing some reduction of flux, a nanoscale zero-valent iron injection was proposed as a more aggressive strategy. Following hydrofracturing to improve hydraulic communication, approximately 800 pounds of nanoscale ZVI was delivered through four injection wells in November/December 2005. While the ZVI injection probably did not reach all contaminated fractures it provides an ongoing reductive capacity to address both the primary source and any back diffusion from the shale and siltstone matrix. Bimonthly molasses injections are currently conducted on the source area and areas of contaminant flux.

Many of the chemicals found in fractured rock sites have DNAPL properties. Effective selection and use of the technologies discussed below requires an understanding of the chemical properties of the specific site contaminants. The CLU-IN DNAPL Focus Area contains extensive discussions on the chemical properties of a wide variety of DNAPL chemicals and the technologies that are effective for each, and other Contaminant Focus sections provide similar information for 1,4-dioxane, MTBE, and perchlorate.


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Bioremediation | Containment | In Situ Flushing | In Situ Oxidation | In Situ Reduction | In Situ Thermal Treatment | Soil Vapor Extraction (SVE) | General Remediation Resources

Bioremediation

As in unconsolidated aquifers, microbes capable of biodegrading dissolved contaminants might be found in bedrock aquifers, and in both cases the groundwater might require reduction-oxidation potential adjustment and/or bioaugmentation. A more detailed discussion of bioremediation of chlorinated solvents is available on CLU-IN.

Biodegradation of Chlorinated Ethenes at a Karst Site in Middle Tennessee
Byl, T.D. and S.D. Williams.
U.S. Geological Survey Water-Resources Investigations Report 99-4285, 65 pp, 2000

This report examines the natural anaerobic degradation of chlorinated ethenes in a karst aquifer.

Biodegradation Potential of MTBE in a Fractured Chalk Aquifer Under Aerobic Conditions in Long-Term Uncontaminated and Contaminated Aquifer Microcosms
Shah, N.W., S.F. Thornton, S.H. Bottrell, and M.J. Spence.
Journal of Contaminant Hydrology 103(3-4)119-133(2009)
Abstract

Adobe PDF LogoDNAPL Dissolution in Bedrock Fractures and Fracture Networks
Schaefer, C., J. McCray, K. Christensen, P. Altman, P. Clement, and J. Torlapati.
SERDP Project ER-1554, 146 pp, 2011

This project focused on measuring and evaluating the architecture, dissolution rate, and impact on groundwater quality of residually trapped PCE DNAPL from discrete bedrock fractures and fracture networks constructed at the bench scale. This work showed that residual DNAPL in rock fractures is not well contacted by migrating water, resulting in reduced dissolution rates and persistence of DNAPL sources within the bedrock fractures. Bioaugmentation substantially enhanced the rate of DNAPL removal, despite dissolved PCE concentrations that were near solubility. ISCO was ineffective for treating DNAPL sources in bedrock fractures due to decreases in the effective DNAPL-water interfacial area, likely from oxidation reaction byproducts.

Flowpath Independent Monitoring of Reductive Dechlorination Potential in a Fractured Rock Aquifer
Bradley, P.M., P.J. Lacombe, T.E. Imbrigiotta, F.H. Chapelle, and D.J. Goode.
Ground Water Monitoring & Remediation 29(4):46-55(2009)
Abstract

This paper presents ways to verify the anaerobic degradation of chlorinated ethenes in fractured rock systems.

Adobe PDF LogoFracture Emplacement of a Micro-Iron/Carbon Amendment for TCE Reduction in a Bedrock Aquifer
Adventus Group.
7th International Battelle Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey California, May 2010. 23 presentation slides, 2010

High-Pressure Injection of Dissolved Oxygen for Hydrocarbon Remediation in a Fractured Dolostone Aquifer
Greer, K.D., J.W. Molson, J.F. Barker, N.R. Thomson, and C.R. Donaldson.
Journal of Contaminant Hydrology, 2010
Abstract

Lessons Learned from Bedrock Blast Fracturing and Bioremediation at a Superfund Landfill
Pearson, S.C. B.B. Johnson, N. Walter, R. Galloway, and S. Waldo.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 13-15, 2004, Portland, Maine.
AbstractAdobe PDF Logo

Hydrogen release compound was used to remediate a fractured rock aquifer contaminated with chlorinated solvents and fuel-related VOCs.

Example Sites

Active Manufacturing Site, Northern Area, NJ
Molasses/zero-valent iron was used as a biostimulant to address PCE contamination, including a DNAPL source zone.

Former Naval Surface Warfare Center, White Oak - OU19, Silver Spring, MD
Following pneumatic fracturing, a 60% oil emulsion was used as a biostimulant to address PCE, TCE, and DCE contamination.

Former Tredegar Film Products, Hunterdon County, NJ
Hydrogen release compound was used as a biostimulant to address PCE contamination.

ITT Industries Night Vision Plant Building # 3, Roanoke, VA
Air, nutrients, and methane were injected to facilitate cometabolic degradation of TCE, VC, chloroethanes, acetone, and isopropyl alcohol.

Letterkenny Army Depot: Building 37, Chambersburg, PA
Sodium lactate was used as a biostimulant to address PCE, TCE, DCE, and VC contamination.

Recticon/Allied Steel Corporation, Parker Ford, PA
Hydrogen release compound was used as a biostimulant to address PCE, TCE, DCE, VC, TCA, and DCA.

Union Chemical Co., Inc., South Hope, ME
Molasses and sodium lactate were used as biostimulants to address xylenes, PCE, TCE, and 1,1-DCE.

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Containment

Hydraulic control by pump and treat is the principal technology used in containment strategies. The hydraulic transmissivity of the aquifer can be increased through hydraulic fracturing or controlled blasting. Care must be taken not to create preferential flow paths that are not captured by the pumping system. Fractured bedrock aquifers that have dead-end fractures and any primary porosity will be subject to diffusion and back-diffusion processes that will extend the time needed to remediate the site.

Permeable reactive barriers are another form of containment. In fractured bedrock zero-valent iron slurry can be injected into a fracture zones; however, achieving a continuous wall across all fractures could be difficult. See in situ reduction section.

Adobe PDF LogoUsing Major Ions Data to Support the Demonstration of Hydraulic Containment in a Fractured Bedrock Aquifer
Sayko, S.P., W.F. Daniels, and R.J. Passmore.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 13-15, 2004, Portland, Maine. 100-114(2004)

Adobe PDF LogoRemediation of a Fractured Rock Aquifer Containing Trichloroethylene Dense Nonaqueous Phase Liquid
Orient, J., L. Monaco, K. Davies, and R.A. Sloto.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. 315-327(2007)

This is a pump and treat site.

Example Sites

Eastman Kodak Company - Kodak Park, Rochester, NY
Pump and treat was chosen to address groundwater contaminated with methylene chloride, dichloropropane, cyclohexane, benzene, toluene, xylene, isopropyl ether, methanol, butanol, various phthalates, 1,4-dioxane, cellosolve, and pyridine.

Re-Solve, Inc., North Dartmouth, MA
Pump and treat was selected to address groundwater contaminated with TCE, PCE, 2-butanone, and methylene chloride

Union Chemical Co., Inc., South Hope, ME
This site chose pump and treat to contain PCE, TCE, and DCE in the groundwater.

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In Situ Flushing

This technology generally is used for addressing non-aqueous phase liquid source zones. Because of the difficulty in fully delineating source zones and controlling where the contaminants might go if mobilized, ITRC (2003) recommends against the use of in situ flushing in fractured rock. A more detailed discussion of in situ flushing technology is available on CLU-IN.

Adobe PDF LogoTechnical and Regulatory Guidance for Surfactant/Cosolvent Flushing of DNAPL Source Zones.
ITRC, 140 pp, 2003

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In Situ Oxidation

In situ oxidation involves the injection or infiltration of chemical oxidants into bedrock fractures where they react with the contaminants and destroy them. Common oxidants include Fenton's reagent, hydrogen peroxide, sodium and potassium permanganate, sodium persulfate, and ozone.

Ensuring that all contaminated fractures are well mixed with the oxidant can be challenging. Because the oxidants remain active for a relatively short period, bedrock with back-diffusion issues will require multiple oxidant applications. For example, Fenton's reagent remains active in the subsurface for minutes to hours, persulfate hours to weeks, depending upon the activating agent, and permanganate for greater than three months (Huling and Pivetz 2006). A more detailed discussion of in situ oxidation is available on CLU-IN.

Adobe PDF LogoAssessment of TCE Oxidation by KMnO4 using Stable Carbon and Chlorine Isotopes at a Fractured Bedrock Site
Helsena, J., R. Aravena, M. Zhanga, O. Shouakar-Stasha, and L. Burns.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. 94-107(2007)

Adobe PDF LogoFractured Crystalline Bedrock Ground Water Remediation of Dissolved TCE via Sodium Permanganate Solution Injection & Re-circulation.
Simons, W.F. and P.D. Steinberg.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 13-15, 2004, Portland, Maine. 417-424(2004)

Adobe PDF LogoFull-Scale Permanganate Remediation of Chlorinated Ethenes in Fractured Shale: Part 1. Site Characterization and Design and Implementation of Full-Scale Remedy
Goldstein, K., A.R. Vitolins, D. Navon, S.W. Chapman, B.L. Parker, and T.A. Al.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. Abstract

Adobe PDF LogoIn-Situ Chemical Oxidation
Huling, Scott G. and Bruce E. Pivetz
USEPA, EPA/600/R-06/072, 60 pp, 2006

Adobe PDF LogoTechnical and Regulatory Challenges Resulting from VOC Matrix Diffusion in a Fractured Shale Bedrock Aquifer
Vitolins, A.R., K.J. Goldstein, D. Navon, G.A. Anderson, S.P. Wood, B. Parker, and J. Cherry.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 13-15, 2004, Portland, Maine. 115-126(2004)

Describes the use of permanganate to address chlorinated VOCs.

Example Sites

Brown's Battery Breaking, Hamburg, PA
Lead was immobilized with sodium bicarbonate.

Commodore Semiconductor Group, Norristown, PA
Potassium and sodium permanganate were used to address TCE (predominating), DCE, chlorobenzenes, and chloroethanes.

Dublin TCE, Dublin Borough, PA
Potassium permanganate was used to oxidize TCE contamination.

Eastland Woolen Mills, Corrina, ME
Chlorinated benzenes were addressed with activated sodium persulfate.

Union Chemical Co., Inc., South Hope, ME
Permanganate and hydrogen peroxide were used to address the principal contaminants: xylenes, TCE, PCE, and 1,1-DCE.

Valmont TCE, West Hazelton, PA
Potassium permanganate was used to address TCE contamination.

West Kingston Town Dump/URI Disposal Area, South Kingstown, RI
PCE, TCE, and TCA contamination was oxidized with sodium permanganate.

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In Situ Reduction

In situ reduction involves injecting a reducing agent into the groundwater. The most widely used reducing agent is zero-valent iron (ZVI) in either a water slurry or an oil emulsion slurry. As with oxidation, achieving effective contact of the iron with the contaminants can be challenging, especially in fractures with small apertures. Because ZVI is relatively long lived (years), it can be used to address back diffusion. A more detailed discussion of in situ reduction technology is available on CLU-IN.

Adobe PDF LogoFracture Emplacement of a Micro-Iron/Carbon Amendment for TCE reduction in a Bedrock Aquifer
Adventus Group.
7th International Battelle Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey California, May 2010. 23 presentation slides, 2010

Example Sites

Active Manufacturing Site, Northern Area, NJ
ZVI and molasses were used as a reductant and biostimulant to address PCE contamination, including a DNAPL source zone.

Caldwell Trucking, Fairfield Township, NJ
Superfund Site Progress Profile
ZVI in a guar/iron slurry was injected into a TCE plume to prevent contamination from discharging to surface water. The treatment reduced contaminant concentrations, but did not meet regulatory levels.

Nease Chemical Site, Columbiana County, OH
In a field study, nanoscale ZVI was injected to treat highly contaminated groundwater (PCE and TCE) in fractured sedimentary bedrock and support design of a full-scale treatment.

Precision National Plating Site, Clarks Summit, Lackawanna County, PA
Beginning in 2006, injections of calcium polysulfide in soil, weathered rock, and shallow bedrock have been implemented at intervals to address Cr(VI) and reduce contaminant concentrations in surface water.

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In Situ Thermal Treatment

In situ thermal remediation involves the introduction of heat into the subsurface to produce steam from water and vaporize and/or destroy organic contaminants. The steam and volatilized organics are captured by vacuum extraction. Three methods can be used to introduce the heat: steam injection, electrical resistive heating (ERH), and conductive heating. Resistive heating passes an electrical current through the subsurface, and the resistance effect produces heat. Since the resistivity depends on moisture content to work, its upper operating temperature is 100°C, the temperature at which water boils. Conductive heating uses heater wells to raise subsurface temperatures and is capable of reaching much higher temperatures than either steam or ERH.

The results of two steam demonstrations found in the literature indicated that steam is likely not the best choice for bedrock with small fracture openings; however it was used in a different bedrock setting with some success at a pilot study at Edwards Air Force Base. Hence its use is very site specific. ERH and conductive heating, which do not rely on fluid flow for heating, are probably better suited for bedrock with small fracture openings. A more detailed discussion of in situ thermal technologies is available on CLU-IN.

Adobe PDF LogoAssessing the Influence of Ground Water Inflow on Thermal Conductive Heating in Fractured Rock
Baston, D., G. Heron, and B.H. Kueper
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. 116-130(2007)

Adobe PDF LogoAssessment of a Large Scale In-Situ Thermal Treatment Project Performed at a Chlorinated Solvent Site in the UK
Baldock, J., L. Chesher, D. Reid, A.-M. Sexton, A. Thomas, S. Tillotson, R. Niven, K. Johnson, and J. Dablow.
AquaConsoil 2013, 16-19 April 2013, Barcelona. Paper 1954, 7 pp, 2013

At an active UK manufacturing facility, the main mass of chlorinated solvent (mainly cis-1,2-DCE and VC) contamination lay within the matrix of underlying saturated, confined, and fractured bedrock. The remedial design combined 23 steam injection locations and 20 dual-phase vacuum extraction (DPVE) wells. Although a relatively energy-intensive remediation approach, thermal treatment was identified as the most rapid strategy for actively removing mass from bedrock. The total mass removed was calculated at ~1,000 kg. Asymptotic conditions with respect to mass removal were achieved within 14 weeks. Steam injection processes were monitored via a network of thermocouples and interpreted using PC-based software. DPVE performance also was assessed via regular flow and VOC quantification. A preliminary assessment indicated that the thermal remediation carbon footprint was 1,611 tonnes CO2-equivalent to remove ~1,000 kg of mass.

Adobe PDF LogoDense Non Aqueous Phase Liquid (DNAPL) Removal from Fractured Rock Using Thermal Conductive Heating (TCH)
Lebron, C.A., D. Phelan, G. Heron, J. LaChance, S.G. Nielsen, B. Kueper, D. Rodriguez, A. Wemp, D. Baston, P. Lacombe, and F.H. Chapelle.
Contract Report CR-NAVFAC ESC-EV-1202, ESTCP Project ER-200715, 427 pp, Aug 2012

This project conducted (1) treatability studies to ascertain a treatment strategy (duration and temperature) for several rock types, (2) modeling to perform screening calculations and carry out mass estimates, and (3) field application of TCH at Naval Air Warfare Center Trenton, a fractured bedrock site. Treatability study results indicate that heating duration had a greater effect on the degree of PCE and TCE mass removal than heating temperature. In 97 days of continuous heating in the field, the average reduction in TCE concentrations was 41-69%; however, the rock matrix did not achieve the targeted temperature in all locations, due mostly to contaminated groundwater influx thru existing fractures. Additional information: ESTCP Cost and Performance Report Adobe PDF Logo

Steam Enhanced Remediation Research for DNAPL in Fractured Rock, Loring Air Force Base, Limestone, Maine
Davis, E., N. Akladiss, R. Hoey, B. Brandon, M. Nalipinski, S. Carroll, G. Heron, K. Novakowski, and K. Udell.
EPA 540-R-05-010, 211 pp, 2005

A demonstration project was conducted using steam to recover chlorinated solvents (PCE) and fuel hydrocarbons in a fractured limestone.

Thermal Conductive Heating in Fractured Bedrock: Screening Calculations to Assess the Effect of Groundwater Influx
Bastona, D.P. and B.H. Kueper.
Advances in Water Resources 32(2)231-238(2009)
Abstract

Adobe PDF LogoUse of Thermal Conduction Heating for the Remediation of DNAPL in Fractured Bedrock
Heron, G., R.S. Baker, J.M. Bierschenk, and J.C. LaChance.
Remediation of Chlorinated and Recalcitrant Compounds: Proceedings of the Sixth International Conference, May 19-22, 2008. Battelle Press, Columbus, OH. 8 pp, 2008

Conductive heating was applied successfully to a TCE source zone in sapprolite and fractured gneiss.

Example Sites

Former PR-58 Nike Missile Battery Site, Davisville, RI
Steam was used to treat tetraTCA, triTCA, PCE, TCE, and carbon tetrachloride in fractured rock. There were difficulties in getting steam into bedrock microfractures.

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Soil Vapor Extraction (SVE)

SVE involves placing recovery wells into the subsurface and applying a vacuum to them. This technology generally is used in the vadose zone; however, some fractured bedrock sites have used dual-phase extraction wells that have long screens and draw water as well as vadose zone vapors to an aboveground treatment system. SVE is also used in conjunction with thermal technologies to capture any vaporized contaminant. A full discussion of SVE technology is available on CLU-IN.

Example Sites

Adobe PDF LogoXerox Corporation, Joseph C. Wilson Center for Technology, Webster, NY
Dual-phase extraction wells were placed in blasted recovery trenches to capture air and water contaminated with PCE, TCE, DCE, TCA, VC, and toluene.

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General Remediation Resources

Adobe PDF LogoBlast Fracturing: Installation and Evaluation of a Fractured Bedrock Zone within Granitic Bedrock at Edwards AFB
Henkes, M., S. Grossi, D. Britton, and P. Hallman.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. 298-311(2007)

Adobe PDF LogoCharacteristics of Fractured Rock Hydrogeology that Impact on Contaminated Site Remediation
Gale, J.E., E. Seok, and G.G. Bursey.
2001 International Containment & Remediation Technology Conference and Exhibition, Orlando, Florida. Florida State University, 3 pp, 2001

Adobe PDF LogoDeveloping Remedial Strategies in a Mixed Porous Medium/Fractured Rock System: Lemberger Site, Whitelaw, Wisconsin
Wedekind, J.E., K.R. Bradbury, P.M. Chase, M.B. Gotkowitz, E. Gredell, K.D. Krause, and J.M. Rice.
Fractured Rock Conference: State of the Science and Measuring Success in Remediation, September 24-26, 2007, Portland, Maine. 389-402(2007)

Adobe PDF LogoThe Economics of Remediating NAPLs in Fractured Aquifers
Hardisty, P.E. and E. Ozdemiroglu.
Proceedings of the National Ground Water Association Cost of Clean-Up Conference, 12 pp, 2005

Microfracture Surface Characterizations: Implications for In Situ Remedial Methods in Fractured Rock
Eighmy, T., J.C.M. Spear, J. Case, H. Marbet, J. Casas, W. Bothner, J. Coulburn, L.S. Tisa, M. Majko, E. Sullivan, M. Mills, K. Newman, and N.E. Kinner.
EPA 600-R-05-121, 99 pp, 2005

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