Bioremediation of Sediments Contaminated with Polyaromatic Hydrocarbons

EPA Grant Number: R825513C020
Subproject: this is subproject number 020 , established and managed by the Center Director under grant R825513
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - South and Southwest HSRC
Center Director: Reible, Danny D.
Title: Bioremediation of Sediments Contaminated with Polyaromatic Hydrocarbons
Investigators: Ward, C. Herb , Hughes, Joseph B
Institution: Rice University
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 1995 through January 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: Hazardous Substance Research Centers , Land and Waste Management


The research in this study focuses on requirements for application of bioremediation technology for cleanup of PAH contaminated sediments. In this project we examined the factors that control the design, operation, and effectiveness of sediment bioremediation processes. Specifically, the following were investigated;

1) Extent of treatment possible with highly contaminated, aged sediments (as a function of PAH type, bioavailability, and microbial diversity/genotype).
2) Microbial and physical-chemical parameters that control degradation of high molecular weight PAHs.
3) Optimization of slurry reactor operation (for example, mixing and/or aeration rates, bioaugmentation, and surfactants to increase bioavailability).
4) Use of a solid-phase oxygen source as a pretreatment to prevent volatile organic carbon emissions when highly reduced anaerobic sediments are aerated for PAH bioremediation.


PAH Biodegradation in Highly Contaminated Sediments
Initial studies focused on the degradation of PAHs in highly contaminated sediments from Utica Harbor (Utica, NY). These sediments (supplied by the Niagra Mohawk Power Company) were contaminated over 70 years ago during the operation of a coal gasification plant, and contain total PAH concentrations as high as 7,000 mg/kg (primarily 2-,3-, and 4-ring compounds). Hence, the contaminants should be highly sorbed and bioavailability should limit both the rate and extent of contaminant biodegradation. These studies will be conducted in small slurry reactors (200ml). Initial experiments addressed rates and extent of degradation achieved under "ideal"laboratory conditions. Additional experiments using these sediments were conducted to investigate adaptation and selection (population shifts) of PAH-degrading organisms during the treatment process.

Parameters that Control Biodegradation of High Molecular Weight PAHs
These studies focused on the effects of multiple contaminants on degradation patterns in slurry reactors. Possible effects include co-oxidation and sequential utilization. Experiments used sediments prepared in-house with defined mixtures (two to four PAHs), and will focus on the influence of 2- and 3-ring PAHs on the degradation of 4- and 5-ring PAHs. Abiotic controls were maintained for all studies using HgCl2 (250 mg/L), and all experiments were conducted at least in duplicate. Initial studies were conducted in a matrix design with sediments contaminated with known levels of PAHs. To avoid volatilization losses, sealed systems were used with adequate headspace to ensure aerobic conditions.

Optimization of Slurry Reactors to Enhance Rates and Extent of Biodegradation while Minimizing Volatilization
A laboratory scale slurry reactor was constructed that was capable of controlling DO and mixing intensities, and equipped with on-line monitoring of CO2 production and hydrocarbon traps. Reactors were constructed to control gas flow rates (either at preset constant rates or to maintain a constant DO in the reactor) and mixed with variable speed high torque mixers. Initial studies focused on control of gas flow rates to minimize stripping losses. Experiments were conducted under various air flow strategies (constant rate, constant DO) while monitoring biodegradation rates on volatilization losses. Biodegradation rates were quantified by CO2 evolution and extractions of sediment samples. The possible effects of bioaugmentation on slurry reactor performance were also be studied. Bioaugmentation may be effective for high molecular weight PAHs if population shifts are essential to their degradation.

ORC Control of VOC Emissions from Bioreactors
In previous experiments we found that the initial oxygen demand of anaerobic sediments can be met by aeration and by the addition of hydrogen peroxide. Large amounts of hydrogen peroxide are often required, but hydrogen peroxide at high concentrations is toxic to bacteria (Fiorenza, 1992) and may adversely affect subsequent sediment bioremediation. A new solid metal peroxide may offer a solution to the VOC problem if it can be formulated to the special requirements of bioreactors. The Oxygen Release Compound (ORC) is a magnesium peroxide and breaks down when hydrated to yield oxygen and magnesium hydroxide (milk of magnesia). The parent chemical and the end products are non-toxic and can be disposed without regulatory concern. Experiments to meet the objective of VOC control from disturbed sediments involved a sequential series of experiments to determine the formulation and application methods best suited for use with bioreactors.

Publications and Presentations:

Publications have been submitted on this subproject: View all 16 publications for this subprojectView all 392 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 6 journal articles for this subprojectView all 106 journal articles for this center

Supplemental Keywords:

bioavailability, volatile organics, and remediation., RFA, Scientific Discipline, Waste, Water, Chemical Engineering, Contaminated Sediments, Environmental Chemistry, Analytical Chemistry, Hazardous Waste, Bioremediation, Ecology and Ecosystems, Hazardous, Environmental Engineering, hazardous waste management, hazardous waste treatment, risk assessment, sediment treatment, environmental technology, decontamination of soil and water, soil and groundwater remediation, biodegradation, risk management, contaminated sediment, decontamination of soil, slurry reactors, chemical contaminants, contaminated soil, contaminants in soil, remediation, bioremediation of soils, PAHs, biotransformation, technology transfer, extraction of metals, anaerobic biotransformation, waste mixtures, CERCLA, contaminated soils

Progress and Final Reports:

  • 1995
  • Final Report

  • Main Center Abstract and Reports:

    R825513    HSRC (1989) - South and Southwest HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825513C001 Sediment Resuspension and Contaminant Transport in an Estuary.
    R825513C002 Contaminant Transport Across Cohesive Sediment Interfaces.
    R825513C003 Mobilization and Fate of Inorganic Contaminant due to Resuspension of Cohesive Sediment.
    R825513C004 Source Identification, Transformation, and Transport Processes of N-, O- and S- Containing Organic Chemicals in Wetland and Upland Sediments.
    R825513C005 Mobility and Transport of Radium from Sediment and Waste Pits.
    R825513C006 Anaerobic Biodegradation of 2,4,6-Trinitrotoluene and Other Nitroaromatic Compounds by Clostridium Acetobutylicum.
    R825513C007 Investigation on the Fate and Biotransformation of Hexachlorobutadiene and Chlorobenzenes in a Sediment-Water Estuarine System
    R825513C008 An Investigation of Chemical Transport from Contaminated Sediments through Porous Containment Structures
    R825513C009 Evaluation of Placement and Effectiveness of Sediment Caps
    R825513C010 Coupled Biological and Physicochemical Bed-Sediment Processes
    R825513C011 Pollutant Fluxes to Aquatic Systems via Coupled Biological and Physicochemical Bed-Sediment Processes
    R825513C012 Controls on Metals Partitioning in Contaminated Sediments
    R825513C013 Phytoremediation of TNT Contaminated Soil and Groundwaters
    R825513C014 Sediment-Based Remediation of Hazardous Substances at a Contaminated Military Base
    R825513C015 Effect of Natural Dynamic Changes on Pollutant-Sediment Interaction
    R825513C016 Desorption of Nonpolar Organic Pollutants from Historically Contaminated Sediments and Dredged Materials
    R825513C017 Modeling Air Emissions of Organic Compounds from Contaminated Sediments and Dredged Materials title change in last year to "Long-term Release of Pollutants from Contaminated Sediment Dredged Material"
    R825513C018 Development of an Integrated Optic Interferometer for In-Situ Monitoring of Volatile Hydrocarbons
    R825513C019 Bioremediation of Contaminated Sediments and Dredged Material
    R825513C020 Bioremediation of Sediments Contaminated with Polyaromatic Hydrocarbons
    R825513C021 Role of Particles in Mobilizing Hazardous Chemicals in Urban Runoff
    R825513C022 Particle Transport and Deposit Morphology at the Sediment/Water Interface
    R825513C023 Uptake of Metal Ions from Aqueous Solutions by Sediments
    R825513C024 Bioavailability of Desorption Resistant Hydrocarbons in Sediment-Water Systems.
    R825513C025 Interactive Roles of Microbial and Spartina Populations in Mercury Methylation Processes in Bioremediation of Contaminated Sediments in Salt-Marsh Systems
    R825513C026 Evaluation of Physical-Chemical Methods for Rapid Assessment of the Bioavailability of Moderately Polar Compounds in Sediments
    R825513C027 Freshwater Bioturbators in Riverine Sediments as Enhancers of Contaminant Release
    R825513C028 Characterization of Laguna Madre Contaminated Sediments.
    R825513C029 The Role of Competitive Adsorption of Suspended Sediments in Determining Partitioning and Colloidal Stability.
    R825513C030 Remediation of TNT-Contaminated Soil by Cyanobacterial Mat.
    R825513C031 Experimental and Detailed Mathematical Modeling of Diffusion of Contaminants in Fluids
    R825513C033 Application of Biotechnology in Bioremediation of Contaminated Sediments
    R825513C034 Characterization of PAH's Degrading Bacteria in Coastal Sediments
    R825513C035 Dynamic Aspects of Metal Speciation in the Miami River Sediments in Relation to Particle Size Distribution of Chemical Heterogeneity