Bioremediation of Oil- Bioremediation of Oil- Contaminated Sites Contaminated Sites Case Studies Involving Light and Heavy Case Studies Involving Light and Heavy Petroleum Hydrocarbons Petroleum Hydrocarbons Talaat Balba, M.S.C., Ph.D. Conestoga-Rovers & Associates
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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
� 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 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 cont’’d...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
� 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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TEM TPH PAHs
With Cultivation
Without Cultivation
ConclusionsConclusions
� Bioremediation is promising technology fortreatment of wide range of contaminants insoil and groundwater, particularly oilcontamination
� Bioremediation is site-specific; therefore,treatability studies are highly recommendedbefore full-scale remediation is considered
Conclusions (contConclusions (cont’’d)d)
� Degradation rate of hydrocarbons isdependent on type of contaminants, metaboliccapabilities of indigenous microbialpopulation, and also on predominantenvironmental factors
� Effectiveness depends to great extent onsuccess in identifying rate–limiting factorsand optimizing them during feasibility studies
Conclusions (contConclusions (cont’’d)d)
� Important to define limitations to the process;both with respect to range of contaminantsthat can be treated and residualconcentrations that can be achieved within anappropriate time frame