Final Report: Remediation of Soil Contaminated with an Organic Phase

EPA Grant Number: R825549C039
Subproject: this is subproject number 039 , established and managed by the Center Director under grant R825549
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Great Plains/Rocky Mountain HSRC
Center Director: Erickson, Larry E.
Title: Remediation of Soil Contaminated with an Organic Phase
Investigators: Erickson, Larry E. , Fan, L. T.
Institution: Kansas State University
EPA Project Officer: Hahn, Intaek
Project Period: May 18, 1992 through May 17, 1996
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Organic Chemical Contamination of Soil/Water , Land and Waste Management


  • To develop mathematical models to determine rate limiting factors for remediation of NAPL-contaminated soil and to estimate the remediation time as a function of NAPL concentration and distribution.
  • To examine rate-limiting factors for bioremediation; they include oxygen and nutrient transfer, microbial growth, and hydrocarbon transport in the aqueous phase.
  • To carry out experimental work to provide quantitative support and verification of the modeling and simulation studies.

Summary/Accomplishments (Outputs/Outcomes):

Oil-rich phases are found in a variety of contaminated sites including locations of oil and gas exploration or drilling, coal-gas plants, leaking tanks, wood treating, and oil refining. Remediation of such sites may require decades. A review of the literature indicates that little has been done to quantitatively model bioremediation under conditions where a hydrocarbon phase exists. Understanding the rate limiting factors will allow for better remediation engineering designs at sites contaminated with Non-Aqueous Phase Liquid (NAPL).

Models will be developed for remediation of a single hydrocarbon deposit through bioremediation, diffusion of the hydrocarbon contaminant through water (pump-and-treat), and volatilization of the contaminant (vacuum extraction). This approach is based on the expectation that phenomena occurring in the vicinity or on the surface of the hydrocarbon deposit may be rate limiting, thereby determining the required remediation time.

The impact of entrained NAPL on remediation times was studied by resorting to three mathematical models, namely, the diffusive, advective, and equilibrium models. The diffusive model considers diffusion and reaction in pores and aggregates while the advective and equilibrium models are applied to flow conditions. The diffusive model builds on the work of Dhawan et al. (Env. Progr. 10:251,1991) by adding a shrinking NAPL core to the aggregate continuum. Analyses of limiting cases indicate that NAPL solubility is the greatest determinant of whether oxygen or NAPL transport is the rate-limiting factor. The results are presented in McDonald et al. (1993) and the thesis of McDonald (1994).

The advective model considers constant flow in a homogeneous isotropic aquifer contaminated with NAPL. Numerous field data and experimental results indicate that the non-wetting fluids of the NAPL in groundwater are trapped, i.e., completely surrounded by the wetting aqueous phase. In the present model, therefore, the NAPL is treated as discrete blobs, while the aqueous phase is considered to be continuous. Interactions between the two liquid phases are incorporated into the governing equations for the aqueous phase. The rates of dissolution and desorption are assumed to be of the first order. Only aerobic growth of microorganisms is taken into account. A series of numerical simulations has been carried out to examine the characteristics of the system, such as the rates of contaminant depletion and biomass growth. The results are described in several manuscripts by Yang et al. (1993a, 1993b, 1994a, 1995a).

The equilibrium model examines bioremediation enhanced pump-and-treat remediation in the saturated zone and bioventing enhanced vapor extraction in the vadose zone. The physical and chemical processes incorporated into the model include dissolution of non-aqueous phase liquids (single as well as multicomponent), sorption of contaminants to organic carbon in the subsurface media, and biodegradation of contaminants. In developing the model, the emphasis was to provide a conceptual understanding of the bioremediation aided, pump-and-treat technology; therefore, various simplifying assumptions were made. The most important among them are equilibrium sorption and dissolution, no substrate toxicity, homogeneous and isotropic porous media, and idealized Darcian flow in NAPL containing pores. The results are described in three manuscripts by Gandhi et al. (1994a, 1994b, 1995) and three manuscripts by Santharam et al. (1995, 1996a, 1996c).

For both bioremediation and pump-and-treat models, the aggregate and NAPL blob sizes have the greatest impact on the remediation time, which has been found to be proportional to the square of the characteristic length. Other primary rate-controlling factors are NAPL solubility, and diffusivity of the contaminant relative to that of oxygen.

Contaminant dissolution is rapid compared to oxygen transfer in the saturated zone for more soluble compounds such as benzene. For slightly soluble compounds such as phenanthrene, oxygen transfer is rapid compared to dissolution. Thus for phenanthrene, microbial growth at the NAPL interface is expected.

The microbial degradation model of Davis et al. (Env. Progr. 12:67, 1993) has been adapted to include a non-aqueous phase. Numerical simulations have provided insight into the limiting factors for pyrene dissolution and biodegradation in the presence of vegetation. The amount of the contaminant present in various phases can be determined from the model. Also, the beneficial effect of vegetation in enhancing the extent of remediation and reducing the groundwater contaminant concentration has been quantified. This work is a cooperative effort with other HSRC projects involving vegetation as a means of enhancing site cleanup. This research is reported by Santharam et al. (1994a, 1994b, and 1996b).

Experimental results, which are in good agreement with models that predict biodegradation and transport, are described in manuscripts of Yang et al. (1995c, 1996). The models have been validated in the light of the experimental data obtained by the present investigators as well as by others.

The investigators have communicated regularly with Dr. Tissa Illangasekare and traveled to Colorado several times to meet with him and his students to coordinate the research activities of projects 91-10 and 91-29. Manuscripts and reports have been exchanged regularly.

The results of this research have been presented at many professional meetings ranging from AIChE national meetings to a special EPA Symposium on Bioremediation of Hazardous Wastes. Copies of manuscripts have been made available to environmental scientists and engineers.

The graduate students who helped with this research are now employed professionally. Two of the graduates are in positions where they are making use of the research in their work.

Journal Articles on this Report : 8 Displayed | Download in RIS Format

Other subproject views: All 29 publications 8 publications in selected types All 8 journal articles
Other center views: All 904 publications 230 publications in selected types All 182 journal articles
Type Citation Sub Project Document Sources
Journal Article Gandhi P, Erickson LE, Fan LT. A simple method to study the effectiveness of bioremediation aided, pump-and-treat technology for aquifers contaminated by nonaqueous phase liquids. I. Single component systems. Journal of Hazardous Materials 1994;39(1):49-68. R825549C039 (Final)
  • Full-text: ScienceDirect-PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Gandhi P, Erickson LE, Fan LT. A simple method to study the effectiveness of bioremediation aided, pump-and-treat technology for aquifers contaminated by nonaqueous phase liquids. II. Multicomponent systems. Journal of Hazardous Materials 1995;41(2-3):185-204. R825549C039 (Final)
  • Full-text: ScienceDirect-PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Santharam SK, Erickson LE, Fan LT. Modelling the role of surfactant and biodegradation in the remediation of aquifers with non-aqueous phase contaminants. Journal of Hazardous Materials 1997;53(1-3):115-139. R825549C039 (Final)
  • Full-text: ScienceDirect-PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Yang XQ, Erickson LE, Fan LT. Dispersive-convective characteristics in the bioremediation of contaminated soil with a heterogeneous formation. Journal of Hazardous Materials 1994;38(1):163-185. R825549C039 (Final)
  • Full-text: ScienceDirect-Full Text HTML
  • Other: ScienceDirect-PDF
  • Journal Article Yang XQ, Erickson LE, Fan LT. A study of the dissolution rate-limited bioremediation of soils contaminated by residual hydrocarbons. Journal of Hazardous Materials 1995;41(2-3):299-313. R825549C039 (Final)
  • Full-text: ScienceDirect-Full Text HTML
  • Other: ScienceDirect-PDF
  • Journal Article Yang XQ, Fan LT, Erickson LE. A conceptual study on the bio-wall technology: feasibility and process design. Remediation 1995;6(1):55-67. R825549C039 (Final)
  • Abstract: Wiley-Abstract
  • Journal Article Yang GX, Erickson LE, Fan LT. A bench-scale study on biodegradation and volatilization of ethylbenzoate in aquifers. Journal of Hazardous Materials 1996;50(2-3):169-182. R825549C039 (Final)
  • Full-text: ScienceDirect-PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article Yang XQ, Erickson LE, Fan LT. A discrete blob model of contaminant transport in groundwater with trapped non-aqueous phase liquids. Chemical Engineering Communications 1996;154(1):33-57. R825549C039 (Final)
  • Abstract: Taylor&Francis-Abstract
  • Supplemental Keywords:

    organic phase, modeling, bioremediation, simulation., RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Water, Geographic Area, Contaminated Sediments, Remediation, Environmental Chemistry, Geochemistry, Analytical Chemistry, chemical mixtures, Hazardous Waste, Oil Spills, Ecology and Ecosystems, Bioremediation, Groundwater remediation, Hazardous, EPA Region, fate and transport, sediment treatment, contaminant transport, NAPL, fate and transport , soil and groundwater remediation, contaminated sediment, oil biodegradation, root zone, contaminated soil, hazardous organic contaminants, oil spill, contaminants in soil, Region 7, bioremediation of soils, Region 8, chemical releases, contaminated groundwater, hydrocarbons, groundwater contamination, hazardous wate, hazardous organic compounds, phytoremediation, contaminated aquifers, groundwater, hydrocarbon degrading

    Relevant Websites: Exit

    Progress and Final Reports:

    Original Abstract
  • 1992
  • 1993
  • 1994

  • Main Center Abstract and Reports:

    R825549    HSRC (1989) - Great Plains/Rocky Mountain HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825549C006 Fate of Trichloroethylene (TCE) in Plant/Soil Systems
    R825549C007 Experimental Study of Stabilization/Solidification of Hazardous Wastes
    R825549C008 Modeling Dissolved Oxygen, Nitrate and Pesticide Contamination in the Subsurface Environment
    R825549C009 Vadose Zone Decontamination by Air Venting
    R825549C010 Thermochemical Treatment of Hazardous Wastes
    R825549C011 Development, Characterization and Evaluation of Adsorbent Regeneration Processes for Treament of Hazardous Waste
    R825549C012 Computer Method to Estimate Safe Level Water Quality Concentrations for Organic Chemicals
    R825549C013 Removal of Nitrogenous Pesticides from Rural Well-Water Supplies by Enzymatic Ozonation Process
    R825549C014 The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
    R825549C015 Adsorption of Hazardous Substances onto Soil Constituents
    R825549C016 Reclamation of Metal and Mining Contaminated Superfund Sites using Sewage Sludge/Fly Ash Amendment
    R825549C017 Metal Recovery and Reuse Using an Integrated Vermiculite Ion Exchange - Acid Recovery System
    R825549C018 Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
    R825549C019 Development of In-situ Biodegradation Technology
    R825549C020 Migration and Biodegradation of Pentachlorophenol in Soil Environment
    R825549C021 Deep-Rooted Poplar Trees as an Innovative Treatment Technology for Pesticide and Toxic Organics Removal from Soil and Groundwater
    R825549C022 In-situ Soil and Aquifer Decontaminaiton using Hydrogen Peroxide and Fenton's Reagent
    R825549C023 Simulation of Three-Dimensional Transport of Hazardous Chemicals in Heterogeneous Soil Cores Using X-ray Computed Tomography
    R825549C024 The Response of Natural Groundwater Bacteria to Groundwater Contamination by Gasoline in a Karst Region
    R825549C025 An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
    R825549C026 Sulfide Size and Morphology Identificaiton for Remediation of Acid Producing Mine Wastes
    R825549C027 Heavy Metals Removal from Dilute Aqueous Solutions using Biopolymers
    R825549C028 Neutron Activation Analysis for Heavy Metal Contaminants in the Environment
    R825549C029 Reducing Heavy Metal Availability to Perennial Grasses and Row-Crops Grown on Contaminated Soils and Mine Spoils
    R825549C030 Alachlor and Atrazine Losses from Runoff and Erosion in the Blue River Basin
    R825549C031 Biodetoxification of Mixed Solid and Hazardous Wastes by Staged Anaerobic Fermentation Conducted at Separate Redox and pH Environments
    R825549C032 Time Dependent Movement of Dioxin and Related Compounds in Soil
    R825549C033 Impact of Soil Microflora on Revegetation Efforts in Southeast Kansas
    R825549C034 Modeling the use of Plants in Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances
    R825549C035 Development of Electrochemical Processes for Improved Treatment of Lead Wastes
    R825549C036 Innovative Treatment and Bank Stabilization of Metals-Contaminated Soils and Tailings along Whitewood Creek, South Dakota
    R825549C037 Formation and Transformation of Pesticide Degradation Products Under Various Electron Acceptor Conditions
    R825549C038 The Effect of Redox Conditions on Transformations of Carbon Tetrachloride
    R825549C039 Remediation of Soil Contaminated with an Organic Phase
    R825549C040 Intelligent Process Design and Control for the Minimization of Waste Production and Treatment of Hazardous Waste
    R825549C041 Heavy Metals Removal from Contaminated Water Solutions
    R825549C042 Metals Soil Pollution and Vegetative Remediation
    R825549C043 Fate and Transport of Munitions Residues in Contaminated Soil
    R825549C044 The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
    R825549C045 Use of Vegetation to Enhance Bioremediation of Surface Soils Contaminated with Pesticide Wastes
    R825549C046 Fate and Transport of Heavy Metals and Radionuclides in Soil: The Impacts of Vegetation
    R825549C047 Vegetative Interceptor Zones for Containment of Heavy Metal Pollutants
    R825549C048 Acid-Producing Metalliferous Waste Reclamation by Material Reprocessing and Vegetative Stabilization
    R825549C049 Laboratory and Field Evaluation of Upward Mobilization and Photodegradation of Polychlorinated Dibenzo-P-Dioxins and Furans in Soil
    R825549C050 Evaluation of Biosparging Performance and Process Fundamentals for Site Remediation
    R825549C051 Field Scale Bioremediation: Relationship of Parent Compound Disappearance to Humification, Mineralization, Leaching, Volatilization of Transformaiton Intermediates
    R825549C052 Chelating Extraction of Heavy Metals from Contaminated Soils
    R825549C053 Application of Anaerobic and Multiple-Electron-Acceptor Bioremediation to Chlorinated Aliphatic Subsurface Contamination
    R825549C054 Application of PGNAA Remote Sensing Methods to Real-Time, Non-Intrusive Determination of Contaminant Profiles in Soils
    R825549C055 Design and Development of an Innovative Industrial Scale Process to Economically Treat Waste Zinc Residues
    R825549C056 Remediation of Soils Contaminated with Wood-Treatment Chemicals (PCP and Creosote)
    R825549C057 Effects of Surfactants on the Bioavailability and Biodegradation of Contaminants in Soils
    R825549C058 Contaminant Binding to the Humin Fraction of Soil Organic Matter
    R825549C059 Identifying Ground-Water Threats from Improperly Abandoned Boreholes
    R825549C060 Uptake of BTEX Compounds by Hybrid Poplar Trees in Hazardous Waste Remediation
    R825549C061 Biofilm Barriers for Waste Containment
    R825549C062 Plant Assisted Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances: Experimental and Modeling Studies
    R825549C063 Extension of Laboratory Validated Treatment and Remediation Technologies to Field Problems in Aquifer Soil and Water Contamination by Organic Waste Chemicals