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  • Bioremediation of Oil-Bioremediation of Oil-Contaminated SitesContaminated Sites

    Case Studies Involving Light and HeavyCase Studies Involving Light and HeavyPetroleum HydrocarbonsPetroleum Hydrocarbons

    Talaat Balba, M.S.C., Ph.D.

    Conestoga-Rovers & Associates

  • Presentation ContentPresentation Content

    Introduction to Petroleum Hydrocarbons

    Characteristics of Petroleum Hydrocarbons

    Problems with Oil Spills

    Treatment Techniques

    Discussion on Bioremediation

    Case Studies

  • Petroleum HydrocarbonsPetroleum Hydrocarbons

    Manufactured from crude oil

    Made mainly from hydrogen and carbon

    Found in crude oil, gasoline, kerosene,heating fuel oil, and asphalt

    Stored and transported in large volumes byship, rail, truck, and pipelines

    One of most prevalent contaminants insubsurface

  • Petroleum HydrocarbonsPetroleum Hydrocarbons

  • Oil Chemical CompositionOil Chemical Composition

    Four main groups of constituents: saturates (or alkanes);

    aromatics, including such compounds as BTEXand PAHs;

    resins, consisting of compounds containingnitrogen, sulphur, and oxygen, that are dissolvedin oil; and

    asphaltenes, which are large and complexmolecules that are colloidally dispersed in oil

  • Petroleum HydrocarbonPetroleum HydrocarbonCharacteristicsCharacteristics

  • Potential Problems AssociatedPotential Problems Associatedwith Oil Spillswith Oil Spills

    Oil migrates down through soils, adsorbing tosoil particles until it reaches groundwater,where oil constituents will dissolve in water,float on water surface (light-end fraction) orsink to bottom of water aquifer (heavyheating fuel oil)

    Any constituent that dissolves in water willtravel with flowing groundwater

  • Treatment TechniquesTreatment Techniques Conventional Methods:

    Free product removal by pump and treat ofgroundwater

    Excavation and off-site disposal of impacted soil

    Vapor extraction

    Innovative cost-effective alternative: Bioremediation

  • What is Bioremediation?What is Bioremediation?

    Treatment process whereby contaminants aremetabolized into less toxic or nontoxiccompounds by naturally occurringmicroorganisms. The microorganisms canutilize many of the oil constituents as asource of carbon and energy. The by-products are mainly carbon dioxide andwater.

  • Oil-Eating BacteriaOil-Eating Bacteria

  • Bioremediation contBioremediation contd...d...

    The microbial population becomes dormantor dies out once all of the contaminantshave been consumed

    Can take place under aerobic or anaerobicconditions in presence of other suitableelectron acceptors such as nitrate, sulfate,or carbonate

    Can be applied in situ or ex situ to treatboth soil and groundwater

  • Key Biochemical ElectronKey Biochemical ElectronAcceptorsAcceptors

    Electron Acceptor Condition Microorganisms

    Oxygen Aerobic Aerobes

    Nitrate Anaerobic Facultative Anaerobes/Denitrifiers

    Sulfate Anaerobic Sulfate Reducers

    CO2 Anaerobic Methanogens

  • Bioremediation contBioremediation contd...d...

    Effective in treating wide range of chemicalsincluding petroleum hydrocarbons

    Two basic ways to treat petroleumhydrocarbon-impacted sites bybioremediation: in situ treatment andtreatment of impacted soil after excavation

  • Key Environmental FactorsKey Environmental FactorsInfluencing Oil BioremediationInfluencing Oil Bioremediation Nutritional factors

    Electron acceptors

    Microbes (degraders) in high numbers

    Soil-water content

    Soil structure and organic content


    Toxic compounds

    Solubility of pollutants

  • Ex Situ MethodsEx Situ Methods


    Composting piles



  • LandfarmingLandfarming

  • Composting PilesComposting Piles

  • BioventingBioventing

  • PhytoremediationPhytoremediation

  • Ways to EnhanceWays to EnhanceBioremediationBioremediation Supplement with suitable sources of nitrogen

    and phosphorus to enhance biodegradation ofSite contaminants by indigenous microbialpopulation

    Injection or infusion of air or oxygen

    Injection of oxygen release compounds(ORC) to optimize aerobic conditions (oilbiodegrades much faster under aerobicconditions)

  • More Ways to EnhanceMore Ways to EnhanceBioremediationBioremediation


    Oxygen infusion through microporousmembranes

    Application of surfactants to enhancebioavailability of heavy oil hydrocarbons andPAHs


  • In situ Biological TreatmentIn situ Biological TreatmentSchemeScheme

  • Case Study #1 - BioremediationCase Study #1 - Bioremediationof Heavy Oils in Soilof Heavy Oils in Soil

    Locomotive maintenance yard in CA

    Soils contaminated with long chain alkanes inC22+ range

    In some areas, levels of contamination werenear soil saturation level

  • Oil ChromatographOil Chromatograph

  • Site SummarySite Summary

    Major Railroad Yard in CA

    30,000 Tons of Oil-Contaminated Soil(Up to 10%)

    Six other similar sites in CA

    Program Included: Lab Treatability Study

    Site Demonstration

  • Site LayoutSite Layout

  • Project SummaryProject Summary

    Cost-effective biological treatment wasdeveloped and field-demonstrated at the site

    Multi-step laboratory treatability studyfollowed by a field demonstration

    Laboratory results showed up to 94 percentremoval of TPH in less than 16 weeks

  • Field Demonstration ResultsField Demonstration Results

    Soils contained over 100,000 mg/Kg drysoil of TPH

    Soils were bioaugmented with mixture ofmicrobial inocula and organic and inorganicfertilizers

    More than 85 percent degradation wasachieved in less than 28 weeks

  • Bioremediation of HeavyBioremediation of HeavyPetroleum Oil in SoilPetroleum Oil in Soil








    0 4 8 12 16 20 24 28

    Time (weeks)

  • Case Study #2 - BioremediationCase Study #2 - Bioremediationof Light Oils in Soilof Light Oils in Soil

    Oil refinery in Germany

    Subsurface soils (up to 20 feet below groundsurface) and groundwater were impacted bynaphthene

  • Field DemonstrationField Demonstration

    Dual treatment process was designed andfield demonstrated at the site

    In situ and ex situ aerobic bioremediation

    Treatments involved application of surface-active agent along with nutrients andmicrobes

  • Description of Dual TreatmentsDescription of Dual Treatments

    Highly contaminated shallow soils (withconcentrations as high as 12,800 mg/Kg)were excavated and treated by landfarming

    Less contaminated soils (highestconcentrations of 180 mg/Kg) were treatedin situ

  • Ex situ TreatmentEx situ Treatment

  • In situ TreatmentIn situ Treatment

  • ResultsResults

    Oil hydrocarbon concentrations in ex situtreatment were reduced to less than2,000 mg/Kg within 24 weeks (an 84 percentreduction)

    In situ treatment results were similar(86 percent reduction to 26 mg/Kg within15 weeks)

  • In situ Treatment ResultsIn situ Treatment Results






    0 5 10 15

    Time (weeks)

  • Case Study #3 - BioremediationCase Study #3 - Bioremediationof Oil-Contaminated Desert Soilof Oil-Contaminated Desert Soil

    Over 49 Km2 of Kuwait's desert soil werecontaminated as result of exploding oil wellsduring Iraqi invasion and occupation of 1990

  • Scope of ProblemScope of Problem

    Over 700 ignited oil wells extinguished andcapped

    Additional areas covered with oil and sootaerosols/heavy contamination

    Remediation required to: restore ecosystems

    avoid underground water contamination

    protect human health

  • TreatmentTreatment

    Bioremediation selected as alternativeremedial option

    Three methods were field-demonstrated atlarge scale: landfarming, composting piles,and bioventing soil piles (with irrigation andbioventing)

  • Correlation of C18:phytane ratiowith TPH degradation


    :phytane ratio TPH concentration (mg/Kg) TPH reduction

    Treatment T0







    Landfarming 2.4 0.3 ND (0.3) 39400 14000 7200 81.7

    Control test 2.4 2.3 2.2 39400 35500 31700 19.5

    Windrow piles 2.4 0.4 ND (0.3) 34700 19400 9500 72.6

    Control test 2.4 2.4 2.2 35900 39800 30600 14.8

    Static piles 1.7 0.5 ND (0.3) 14400 8500 4600 68.1

    Control test 1.7 1.6 1.4 14100 13600 12200 13.5

  • ResultsResults

    Landfarming treatment reduced lightlycontaminated soils by 80 percent within6 months and heavily contaminated soils by80 percent within 12 months

    Results confirm that reduction in TPHconcentration was caused primarily bymicrobial biodegradation and notvolatilization

  • Phytoremediation for PolishingPhytoremediation for Polishing

    Phytoremediation was used as polishingmethod to further reduce residual level ofTPH and to assess phytotoxicity of residualTPH on growth and performance of widerange of domestic and ornamental plantspecies

    Alfalfa vegetation resulted in much cleanersoil as evident from analysis of TPH, totalextractable matter (TEM), and PAHs

  • PhytoremediationPhytoremediation

  • Phytoremediation ResultsPhytoremediation Results








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