Final Report: Biofilm Barriers for Waste ContainmentEPA Grant Number: R825549C061
Subproject: this is subproject number 061 , 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: Biofilm Barriers for Waste Containment
Investigators: Turner, John P. , Bulla, Lee A. , Skinner, Quentin D.
Institution: University of Wyoming
EPA Project Officer: Hahn, Intaek
Project Period: May 18, 1995 through May 1, 1997
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text | Recipients Lists
Research Category: Analysis/Treatment of Contaminated Soil , Land and Waste Management
The objective of this project was to evaluate the feasibility of creating low-permeability waste containment barriers by treating soils with biofilm-producing bacteria. Previous studies strongly suggested significant reductions in soil and rock permeability by certain types of bacteria.
Our rationale was that if these reductions in permeability could be controlled and were sufficient to satisfy the EPA definition of "low permeability" for purposes of waste containment (k < 10-7 cm/sec), then it may be possible to create engineered containment barriers using permeable soils treated with biofilm. Potential applications would include in-situ cutoff walls and compacted liners.
A laboratory study was conducted to evaluate changes in the hydraulic conductivity of a compacted silty sand treated with biofilm.
Values of hydraulic conductivity (k) for this soil without biofilm treatment range from 10-6 to 10-5 cm/sec, depending on moisture content. After screening several types of bacteria, a strain of Beijerinckia indica was selected for its ability to produce a hard, thick exopolysaccharide biofilm. B. indica is a naturally occurring soil microbe which is non-pathogenic to humans. Soil specimens were molded with a solution consisting of B. indica cells and nutrient solution, compacted at optimum moisture, and tested for hydraulic conductivity using a flexible wall permeameter. Significant reductions in k were observed, with most specimens reaching a stable final k of 10-8 cm/sec. Hydraulic conductivity was observed to decrease substantially within 2 to 3 days following molding of specimens, with more gradual reductions over the next 10 to 14 days. The lowest values of k are achieved after approximately two weeks of permeation with nutrient solution.
Durability of the biofilm was tested by permeating biofilm-treated specimens with saline, acidic, and basic solutions, and by subjecting specimens to wet-dry and freeze-thaw conditions. Specimens subjected to saline (0.5 N NaCl), acidic (pH = 3 hydrochloric acid), and basic (pH =11 NaOH) solutions were permeated with 2 to 3 pore volumes of the chemical permeant. Final k of all specimens permeated with chemical solutions ranged from 1 x 10-8 cm/sec to 1 x 10-7 cm/sec, with most specimens showing a final k in the range of 1 to 3 x 10-8 cm/sec. These results demonstrate that the low permeability of specimens treated with biofilm produced by B. indica is highly resistant to degradation by inorganic chemical permeants.
To simulate the effects of adverse environmental conditions, specimens first treated with biofilm were subjected to ten cycles of wet-dry or freeze-thaw conditions. Of three specimens subjected to wet-dry conditions, final values of k were 3 x 10-8, 1 x 10-7, and 2 x 10-7 cm/sec, suggesting moderate increases in hydraulic conductivity. The two specimens exhibiting k in the range of 10-7 cm/sec were then permeated with nutrient solution. This resulted in a decrease of k to 2 x 10-8 cm/sec, suggesting that any detrimental effects of wet-dry conditions are reversible upon further application of nutrient solution. Freeze-thaw conditions were shown to have an adverse effect on k of biofilm-treated specimens. Final values of k ranged from 2 x 10-7 to 2 x 10-6 cm/sec. Subsequent permeation with nutrient solution resulted in restoration of low permeability (k= 2 x 10-8 cm/sec).
Several specimens were treated with biofilm by permeation with a solution of nutrient solution containing ultramicrobacterial (UMB) cells of B. indica, after the specimen had been molded with tap water and compacted (as opposed to molding the specimen with bacterial solution). The objective of these tests was to assess the feasibility of creating biofilm barriers by treating soils in situ. Hydraulic conductivity of these specimens was reduced to values similar to those of the specimens molded with bacterial solutions. k = 1 x 10-8 cm/sec.
The conclusion of this study is that biofilm treatment of soil to create various types of containment barriers is technically feasible and warrants further research and development. Construction of a prototype cutoff wall to further assess the feasibility of this technology at a scale more representative of field conditions is highly recommended. Further bench-scale and prototype-scale research is recommended to evaluate the effects of biofilm on other contaminant transport mechanisms besides advection (controlled by k), such as diffusion, chemical reactions between contaminants and biofilm, and biodegradation.
The results have been presented at several professional meetings and published in professional journals and conference proceedings.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
|Other subproject views:||All 9 publications||1 publications in selected types||All 1 journal articles|
|Other center views:||All 904 publications||230 publications in selected types||All 182 journal articles|
||Dennis ML, Turner JP. Hydraulic conductivity of compacted soil treated with biofilm. Journal of Geotechnical and Geoenvironmental Engineering 1998;124(2):120-127.||
Supplemental Keywords:biofilms, hydraulic conductivity, ultramicrobacteria, waste containment, barriers, RFA, Scientific Discipline, Water, Waste, Contaminated Sediments, Remediation, Environmental Chemistry, Biochemistry, Hazardous Waste, Bioremediation, Groundwater remediation, Hazardous, Environmental Engineering, biofilm, ultramicrobacteria, biodegradation, contaminated sediment, cometabolism, contaminated soil, waste containment, bioremediation of soils, biofilm model, biofilm growth
Progress and Final Reports:Original Abstract
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