Inject - E2S2
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Inject - E2S2

Importance of HydrogeologicCharacterization to EffectiveBioaugmentation of ContaminatedFractured Sedimentary RocksClaire R. TiedemanU.S. Geological SurveyMenlo Park, CaliforniaAllen Shapiro, Pierre Lacombe, Daniel Goode,Paul Hsieh, Tom ImbrigiottaE2S2 Symposium and Exhibition: Management and Treatment of ComplexGroundwater Contamination at DoD InstallationsMay 10, 2011

Characteristics and Complexities ofFractured Rock Aquifers

Characteristics and Complexities ofFractured Rock Aquifers• Presence of fractures and matrix•Different flow and transport propertiesand controlling processes.•Fractures: advection dominates;Matrix: diffusion dominates.•Contaminants that have diffused intothe matrix act as a long-term in-situsource of fracture contamination.•Very difficult to remediate the matrixbecause diffusion controls transport.

Characteristics and Complexities ofFractured Rock Aquifers• Highly heterogeneouscontaminant distributionsRock MatrixBedding Plane Fractures

Given these Characteristics andComplexities...• … Characterization is important to remediation• Understanding contaminant distribution andtransport mechanisms can be critical to designingremediation, and to monitoring its effectiveness.• Characterize while remediating. Examples:• Aquifer tests using pump &treat system.• Focused characterization forbioaugmentation design whilepump & treat occuring.

SedimentaryRocks of NewarkBasinFormer Naval AirWarfare Center(NAWC)West Trenton, NJ

Naval Air Warfare Center (NAWC),West Trenton, New Jersey• Navy jet engine testingfacility 1950’s to 1990’s.• Extensive TCE & DCEcontamination.• Remediation by pump& treat since mid-1990’s.• Characterization, andremediation research,taking place while pump &treat is ongoing.

Bioaugmentation in DippingFractured Mudstones at NAWC• Motivation:Extremely highconcentrations ofTCE have persisteddespite 15 years ofpump and treat.InjectPump• Objectives:Evaluate bioaugeffectiveness inreducing TCEbeyond injectionwell; Understandin-situ processes.Electron donor& MicrobesOne snapshot in time prior to bioaugmentationTCE DCE VC Ethene

Bioaugmentation Design:Questions Related to Hydrogeology• Volume ofamendments(electron donorand microbes) toinject?• Expectedmigration paths?• Pumping rate atextraction well?• Where to monitor?InjectPumpInitial Conceptual Model:• Primary flow path between36BR and 15BR is along onethin fissile mudstone bed.

Hydrogeologic Investigation CriticalTo Bioaugmentation Design• Develop detailedstratigraphic framework• Conduct single & cross-holehydraulic testing• Conduct cross-hole andpush-pull tracer testing

Gamma Ray Logging + Rock Core:Stratigraphic FrameworkConclusions:• Pumping well and injection wellintersect different thin fissilemudstone beds.Lacombe

Single-Hole Hydraulic Testinghigh Khigh K~low Klow KConclusions:• Along beds connecting36BR & 15BR:Low K downdipHigh K updipShapiro & Tiedeman

Cross-Hole Hydraulic TestingAquifertests donein 15BRto assesshydraulicconnectionsPackers separateeach borehole into 5isolated zones.?Conclusions:• Primary flow paths are alongtwo thin fissile mudstone beds.• Cross-bed fractures enableflow between these two beds.Tiedeman & Goode

Cross-Hole Tracer TestingInject 3700 mg/L BromidePumpConclusions:• Huge dilution at pumped well:only small amount of pumpedwater comes from the regionbetween 36BR & 15BR.• > 80% of mass still in aquiferafter 5 months.Shapiro & Goode

Cross-Hole Tracer Testing: Bromide inAquifer 6 Months after InjectionConclusions:• Most of mass is indowndip region low-K rocks/fracturesstrongly retain tracer.Goode & Shapiro

Push-Pull Tracer Test to GuideBioaugmentation Injection Strategy• 170 gallonsBromide solutioninjected at 36BRover a 3 hourperiod.• 1 hour later,Br concentrationbegins to rapidlyincrease ininterval 73BR-D2.Bromide Concentration(mg/liter)3020100Early Time DataInjectionin 36BRWell 73BR, Interval D2Bromideconcentrationstarts to rise0 2 4 6 8Conclusion:Hours Since Start of Injection in 36BR• Inject ~170 gallons EOSplus flush water.• Do not change 15BRpumping rate.Shapiro, Tiedeman, Goode, Imbrigiotta

Bioaugmentation Implementation• Injected:• Electron donor solution(EOS ® ) and microbes knownto degrade TCE (KB-1 ® ).Injectionbladders• Flush water.• Total injection volume:~160 gallonsEOS• EOS ® visible in 73BR-D2water sample taken dayafter injection ofamendments

Summary of TCE ReductionsRed: max TCE conc (µg/l) pre-bioaugBlue: min TCE conc 1.5 yrs post-bioaug5,0005,00084,000

BioaugmentationResults:TCE, DCE,VC & EtheneInjectPump100001000VOCs vs Time - 73BR-D2TCE2BioaugmentationInjectioncisDCEcisDCEVOC concentration (µM)1001010.1cisDCEEtheneEtheneVCTCEEtheneVCTCEResults look promising!BUT…….. What is missingfrom this analysis???Imbrigiotta and others

The Rock Matrix• Profile shows TCEconcentrations in primaryporosity of rock core prior tobioaugmentation.• Samples showing TCEreductions (previous slides)are pumped from fractures.BelowAnalyticalDetectionLimitAboveSaturation:Due toDesorptionor DNAPLDissolution• Is bioaugmentation alsoaffecting concentrations inthe rock matrix?• New core collected August2010 will help answer thisquestion.Goode & Imbrigiotta

Conclusions: Detailed HydrogeologicInvestigation Critical to Bioaug Design• Migration paths morecomplex than originallythought.• Low-K region downdipstrongly controlsdistribution of injectedamendments.• Existing pumping rateat extraction well doesnot need to change.• Monitoring theintermediate locationsis critical because ofhuge dilution at 15BR.Red: max TCE conc (µg/l) pre-bioaugBlue: min TCE conc 1.5 yrs post-bioaug84,000

AcknowledgementsToxic Substances Hydrology ProgramNew Jersey Water Science CenterNational Research ProgramOffice of Ground WaterTechnologyInnovationProgramNavalFacilitiesEngineeringCommand

NAWC: Multiple Parties withUSGS, SERDP, ESTCP,Universities: Researchcontaminant transport,fate, & remediation; andtransfer results.Different ObjectivesU.S. Navy: Remediate &monitor contaminationcost-effectively.NJ Dept. ofEnvironmentalProtection: Cleanup site and preventcontaminants fromspreading.Site owner: Developretail businesses on site.

GW Contamination in FracturedRocks: A National IssueFractured rock sites inEPA CLU-IN database, May 2011

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