Electron Acceptor Selection for Enhanced Bioremediation of Non

Electron Acceptor Selection for Enhanced Bioremediation of Non‐Chlorinated Hydrocarbons
Brad Elkins MS, PG (author)
Presented by Bill Walsh
EOS Remediation, LLC
Raleigh, NC
5th
April 23, 2014
AIPG Georgia Section
Conference On: “Innovative Environmental Assessment and Remediation Technology”
Kennesaw State University Continuing Education, Kennesaw, GA
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What is Bioremediation?
ElectronDonor
•
•
•
•
•
+
NaturalDOC
SodiumLactate
Molasses
VegetableOil(EOS)
Non‐Chlorinatedhydrocarbon
Energy
ElectronAcceptor
•
•
•
•
•
Oxygen
Nitrate
Iron
Sulfate
CVOC(PCE&TCE)
Multiply
=
Waste
CO2,Water
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The ORP Factor
Ground Surface
Carbon Source
Water Table
Aerobic Respiration
O2
H2O
Anaerobic Respiration
Iron-Reduction
Manganese-Reduction
Nitrate-Reduction
Sulfate-Reduction
Methanogenesis
Nitrate-Reduction
Manganese-Reduction
Iron-Reduction
Sulfate-Reduction
Nitrate-Reduction
Manganese-Reduction
Iron-Reduction
Nitrate-Reduction
Manganese-Reduction
Groundwater Flow
Nitrate-Reduction
NO3‐
N2
MnO2
Mn‐2
Fe+3
Fe+2
SO4‐2
H2S
CO2
CH4
Modified:AFCEE,PrinciplesandPracticesofEnhancedAnaerobicBioremediationofChlorinatedSolvents.
August2004
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Literature Review
EPA-BP Study at 74 Sites
sulfate reduction
methanogenesis
nitrate reduction
aerobic oxidation
iron reduction
AFCEE Study at 42 Sites
Ref: Wiedemeier, T.H et al.
at 38 Sites
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Making a Choice
1. Contaminant
‐ PAHs
‐ DRO
‐ Creosote
‐ GRO
‐ MTBE
Aerobic Pathway
AerobicorAnaerobicPathway
2. RedoxState
3. Strategy
‐ Excavation/backfill
‐ Plumemigrationcontrol
‐ Sourceareatreatment
4. Timeframe&Budget
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How Much?
TerminalElectron
AcceptingProcess
Average MassRatioof
ElectronAcceptorto
totalBTEX
MassofBTEXDegraded
per unitMassof
ElectronAcceptor
Utilized(mg/mg)
Oxygen
3.13:1
0.32
C6H5CH3 +9O2
Nitrate
7CO2(g) +4H2O
4.85:1
7.2NO3‐ +7.2H++C6H5CH3
Sulfate
7CO2(g)+7.6H2O+3.6N2(g)
4.7:1
9H+ +4.5SO42‐ +C6H5CH3
0.21
0.21
7CO2(g)+4.5H2So +4H2O
ModifiedfromWiedemeieretal.,1999
Assumingabsenceofmicrobialcellproduction,the
mineralizationoftoluenetocarbondioxideandwater
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Case Study
FormerGasStationimpactedwithBTEX
FormerUSTbasinisnowagrassmedianofNCHighway24/27
Geology:sandsandclayabove
partiallyweatheredbedrock
FormerUSTbasin
Residencelocated250feetsouth
offormerUSTbasinwhich
operatesanirrigationwell
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Case Study
Consultant(Solutions‐IES)preparedaCAPevaluating
threetechnologiesforsiteremediationEAS,ISCO,SVE/AS
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Evaluation Factors
1. ISCO:FastestmethodbutwithH&Sconcernand
expensivereagents.
2. EAS:Requiremultipleinjectionsbuttook
advantageofprevailingaquiferconditionsand
extremelyeasytouseinthefield.
3. SVE/AS:Prospectiveoperationforeightyears
withlimitedextractionduetoheterogeneous
geology.
Solutions‐IES,CAP,2012
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Confirmation
Solutions‐IES,CAP,2012
•
Sulfatereducingconditionspresentinthetargettreatmentarea.
•
AbacterialCENSUSqPCRreportedsulfatereducingpopulationat
9.48x104 cell/ml.
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Pilot Test
Onepermanentinjection
pointwasinstalled;PIW‐1.
Threedowngradient
monitoringwellswere
installed;PWM‐1,PWM‐2,
PMW‐3.
Injectionwasconductedin
June2012.
Fourpostinjection
monitoringevents60‐90
dayapartwereplannedfor
observingperformanceof
thepilottest.
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Pilot Test
OnedrumofEAS™was
injectedintoPIW‐1via
gravityfeedat0.5gpm.
Theproductwasnot
dilutedandnochase
wateradded.
Sulfateincreasewas
detectedatPMW‐1and
PMW‐2,suggestingaROI
of7.5feet.
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Pilot Test: Results
12,000
PIW‐1
PMW‐1
TotalBTEXppb
10,000
PMW‐2
PMW‐3
8,000
6,000
4,000
2,000
0
Dayssinceinjection
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Conclusions  Pilotstudydemonstratedthattheadditionofsulfateasanelectronacceptor
couldstimulatebacteriaintheBTEXimpactedarea.
 ThatstimulationresultedinadecreaseofBTEXconcentrationsattheinjection
wellby75%.
 Radiusofinfluencebetween5ftand10ftfromaninjectionwellispossible.
 Gravityfeedinjectionflowrateof0.5gpmcanbeachieved.
 Reinjectiontimeframeatleast6monthswouldhelpmaintainasulfate‐rich
environmentforextendedtreatmentlongevity.
 Thisprojecthasmovedforwardwithfullscaleimplementationbasedonthe
resultsofthisdemonstration. MultipleEASinjectioneventsarescheduled
during2014and2015.
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Questions
Thankyou!
www.eosremediation.com
BradElkins,MS,PG
TechnicalSalesManager
[email protected]
(919)873‐2204ext.173
Or
BillWalsh
TechnicalSalesRepresentative
[email protected]
(919)605‐8652
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