Grantee Research Project Results

Final Report: Anaerobic Intrinsic Bioremediation of MTBE

EPA Grant Number: R827015C020
Subproject: this is subproject number 020 , established and managed by the Center Director under grant R827015
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (1989) - Northeast HSRC
Center Director: Sidhu, Sukh S.
Title: Anaerobic Intrinsic Bioremediation of MTBE
Investigators: Suflita, Joseph
Institution: University of Oklahoma
EPA Project Officer: Aja, Hayley
Project Period: March 1, 2002 through February 28, 2003
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

In the last two decades, methyl tertiary-butyl ether (MTBE) gained widespread use as an octane enhancer and fuel oxygenate in gasoline and also has become a frequently detected and problematic ground and surface water contaminant. One desirable fate process for oxygenated gasoline in contaminated environments is microbial biodegradation. The objective of this research project was to conduct a series of laboratory studies to conclusively demonstrate the susceptibility of MTBE, and its known metabolite tertiary-butyl alcohol (TBA), to anaerobic biodegradation by inocula from gasoline-contaminated aquifers where BP field monitoring suggests that this is occurring. Ultimately, demonstrating the anaerobic biodegradation of MTBE and understanding the process will help buttress claims for the intrinsic bioremediation of this gasoline-additive in contaminated aquifers.

Summary/Accomplishments (Outputs/Outcomes):

The screening assay for anaerobic MTBE biodegradation was designed by Drs. Suflita, Kropp, and Ulrich and implemented by Dr. Ulrich. The latter individual represents Surbec-ART Environmental L.L.C., the company that conducted the initial screening. The screening assay employed radiolabeled MTBE (14C-MTBE). An assessment of radiolabeled endproduct production at the University of Oklahoma was part of the screening protocol.

MTBE biodegradation under anaerobic and aerobic conditions has been evaluated in sediment slurry incubations prepared with material collected from 10 impacted sites. The initial assay of the incubations was conducted by Surbec-Art. The biodegradation of MTBE in the presence of oxygen has been noted in 7 of the 10 samples evaluated. TBA biodegradation activity was assessed concurrently in parallel incubations prepared with samples from four of the seven sites that tested positive for aerobic MTBE biodegradation. TBA biodegradation was noted in all four, thereby indicating the capacity for complete MTBE biodegradation under aerobic conditions.

The anaerobic biodegradation of MTBE has been detected only in 1 of 10 samples. This activity was dependent on the presence of hydrogen added to the headspace of the incubations. This was not an experimental variable in the original proposal and something that Surbec-Art incorporated into their screening efforts. At this time, it is not known whether the MTBE has been mineralized or converted to TBA via methyl group removal. Radiotracer mass balances and 14C-TBA analyses will be conducted in an effort to make this determination. Therefore, at this time we cannot conclude that there is a significant anaerobic fate process for MTBE beyond the simple methyl group removal.

The analysis of sulfate, soluble ferrous iron, and methane in the anaerobic incubations relative to autoclaved controls revealed that sulfate reduction and methanogenesis were the predominant terminal electron accepting conditions in the anaerobic incubations. Therefore, the experiments have not fully evaluated MTBE biodegradation in the presence of other alternate electron acceptors including iron, manganese, or nitrate.

A comprehensive review of the literature covering the aerobic and anaerobic biodegradation of MTBE in both the laboratory and the field has been prepared and submitted for publication as part of this project.

Supplemental Keywords:

bioremediation, groundwater remediation, oil, spills, anaerobic biodegradation, anaerobic bioremediation, MTBE,, Scientific Discipline, TREATMENT/CONTROL, Waste, Environmental Chemistry, Treatment Technologies, Biochemistry, Bioremediation, gasoline, MTBE, groundwater remediation, petroleum, anaerobic biodegradation

Relevant Websites:

http://ipec.utulsa.edu/ Exit

Main Center Abstract and Reports:

R827015    HSRC (1989) - Northeast HSRC

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827015C001 Evaluation of Road Base Material Derived from Tank Bottom Sludges
R827015C002 Passive Sampling Devices (PSDs) for Bioavailability Screening of Soils Containing Petrochemicals
R827015C003 Demonstration of a Subsurface Drainage System for the Remediation of Brine-Impacted Soil
R827015C004 Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C005 Microflora Involved in Phytoremediation of Polyaromatic Hydrocarbons
R827015C006 Microbial Treatment of Naturally Occurring Radioactive Material (NORM)
R827015C007 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C008 The Use of Nitrate for the Control of Sulfide Formation in Oklahoma Oil Fields
R827015C009 Surfactant-Enhanced Treatment of Oil-Contaminated Soils and Oil-Based Drill Cuttings
R827015C010 Novel Materials for Facile Separation of Petroleum Products from Aqueous Mixtures Via Magnetic Filtration
R827015C011 Development of Relevant Ecological Screening Criteria (RESC) for Petroleum Hydrocarbon-Contaminated Exploration and Production Sites
R827015C012 Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C013 New Process for Plugging Abandoned Wells
R827015C014 Enhancement of Microbial Sulfate Reduction for the Remediation of Hydrocarbon Contaminated Aquifers - A Laboratory and Field Scale Demonstration
R827015C015 Locating Oil-Water Interfaces in Process Vessels
R827015C016 Remediation of Brine Spills with Hay
R827015C017 Continuation of an Investigation into the Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C018 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C019 Biodegradation of Petroleum Hydrocarbons in Salt-Impacted Soil by Native Halophiles or Halotolerants and Strategies for Enhanced Degradation
R827015C020 Anaerobic Intrinsic Bioremediation of MTBE
R827015C021 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R827015C022 A Continuation: Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C023 Data for Design of Vapor Recovery Units for Crude Oil Stock Tank Emissions
R827015C024 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells
R827015C025 A Continuation of Remediation of Brine Spills with Hay
R827015C026 Identifying the Signature of the Natural Attenuation of MTBE in Goundwater Using Molecular Methods and "Bug Traps"
R827015C027 Identifying the Signature of Natural Attenuation in the Microbial Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and "Bug Traps"
R827015C028 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R827015C030 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R827015C031 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R827015C032 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633 Integrated Petroleum Environmental Consortium (IPEC)
R830633C001 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells (Phase II)
R830633C002 A Continuation of Remediation of Brine Spills with Hay
R830633C003 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R830633C004 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R830633C005 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633C006 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R830633C007 Identifying the Signature of the Natural Attenuation in the Microbial Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and “Bug Traps”
R830633C008 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R830633C009 Use of Earthworms to Accelerate the Restoration of Oil and Brine Impacted Sites