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 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC What is Bioremediation? ElectronDonor • • • • • + NaturalDOC SodiumLactate Molasses VegetableOil(EOS) Non‐Chlorinatedhydrocarbon Energy ElectronAcceptor • • • • • Oxygen Nitrate Iron Sulfate CVOC(PCE&TCE) Multiply = Waste CO2,Water Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC 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 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC 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 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Making a Choice 1. Contaminant ‐ PAHs ‐ DRO ‐ Creosote ‐ GRO ‐ MTBE Aerobic Pathway AerobicorAnaerobicPathway 2. RedoxState 3. Strategy ‐ Excavation/backfill ‐ Plumemigrationcontrol ‐ Sourceareatreatment 4. Timeframe&Budget Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC 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 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Case Study FormerGasStationimpactedwithBTEX FormerUSTbasinisnowagrassmedianofNCHighway24/27 Geology:sandsandclayabove partiallyweatheredbedrock FormerUSTbasin Residencelocated250feetsouth offormerUSTbasinwhich operatesanirrigationwell Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Case Study Consultant(Solutions‐IES)preparedaCAPevaluating threetechnologiesforsiteremediationEAS,ISCO,SVE/AS Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Evaluation Factors 1. ISCO:FastestmethodbutwithH&Sconcernand expensivereagents. 2. EAS:Requiremultipleinjectionsbuttook advantageofprevailingaquiferconditionsand extremelyeasytouseinthefield. 3. SVE/AS:Prospectiveoperationforeightyears withlimitedextractionduetoheterogeneous geology. Solutions‐IES,CAP,2012 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Confirmation Solutions‐IES,CAP,2012 • Sulfatereducingconditionspresentinthetargettreatmentarea. • AbacterialCENSUSqPCRreportedsulfatereducingpopulationat 9.48x104 cell/ml. Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Pilot Test Onepermanentinjection pointwasinstalled;PIW‐1. Threedowngradient monitoringwellswere installed;PWM‐1,PWM‐2, PMW‐3. Injectionwasconductedin June2012. Fourpostinjection monitoringevents60‐90 dayapartwereplannedfor observingperformanceof thepilottest. Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Pilot Test OnedrumofEAS™was injectedintoPIW‐1via gravityfeedat0.5gpm. Theproductwasnot dilutedandnochase wateradded. Sulfateincreasewas detectedatPMW‐1and PMW‐2,suggestingaROI of7.5feet. Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC 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 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Conclusions Pilotstudydemonstratedthattheadditionofsulfateasanelectronacceptor couldstimulatebacteriaintheBTEXimpactedarea. ThatstimulationresultedinadecreaseofBTEXconcentrationsattheinjection wellby75%. Radiusofinfluencebetween5ftand10ftfromaninjectionwellispossible. Gravityfeedinjectionflowrateof0.5gpmcanbeachieved. Reinjectiontimeframeatleast6monthswouldhelpmaintainasulfate‐rich environmentforextendedtreatmentlongevity. Thisprojecthasmovedforwardwithfullscaleimplementationbasedonthe resultsofthisdemonstration. MultipleEASinjectioneventsarescheduled during2014and2015. Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC Questions Thankyou! www.eosremediation.com BradElkins,MS,PG TechnicalSalesManager belkins@eosremediation.com (919)873‐2204ext.173 Or BillWalsh TechnicalSalesRepresentative bwalsh@eosremediation.com (919)605‐8652 Experience You Can Rely On, Products You Can Trust™ • www.eosremediation.com • Copyright© 2013 EOS Remediation, LLC
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