Grantee Research Project Results
Final Report: Microbial Treatment of Naturally Occurring Radioactive Material (NORM)
EPA Grant Number: R827015C006Subproject: this is subproject number 006 , 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: Microbial Treatment of Naturally Occurring Radioactive Material (NORM)
Investigators: Krumholz, Lee R.
Institution: University of Oklahoma
EPA Project Officer: Aja, Hayley
Project Period: July 1, 1999 through June 30, 2000
Project Amount: Refer to main center abstract for funding details.
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
Naturally occuring radioactive material (NORM) has been known to be associated with oil and gas deposits for many years. During oil producing operations, large quantities of scale are formed on surfaces of tubing, casings, separators, drilling equipment and water storage vessels, mainly as a result of barium sulfate precipitation. When scale forms, it also hosts the precipitation of Radium (naturally present in groundwater as a daughter of thorium and uranium) as well as other metals including iron and calcium. As there are no currently effective and economically feasible technologies for dissolving and concentrating the scale material, equipment contaminated with NORM containing scale is cleaned mechanically or stored with the intent of disposal.
It has been estimated that between 300,000 and 1,000,000 tons of radioactive scale are produced in the US each year. Virtually all of this scale exceeds the exemption limit of 30 pCi/gm and about 5% has more than 2000 pCi/gm activity. The presence of NORM at oil and gas producing facilities has recently increased in significance as federal and state regulatory agencies lay out more stringent guidelines for transport and disposal.
Although there are no natural conditions in which barium is highly soluble, there have been several previous studies describing the dissolution of barite (barium sulfate) by sulfate reducing bacteria ((Baldi et al., 1996; Bolze et al., 1974; Fedorak, 1986). In each of these studies, the sulfate reduction process converted sulfate associated with barite to sulfide resulting in the release of Ba2+ into solution. Barite was either prepared synthetically (Bolze et al., 1974) or obtained from Sludges ((Baldi et al., 1996; Fedorak, 1986) In each case, pure cultures released less than 36 M Ba2+ into solution from synthetic powdered Barite. Sewage sludge released only 9 M Ba2+, while sulfate reducers in Uranium mill waste sludges released Ba2+ as well as Ra2+ into solution.
In this study, we demonstrate the feasibility of using a sulfate reducing process for the removal of NORM containing pipe scale. Sulfate reducing bacteria associated with subsurface sediments catalyze the release of Ba2+ and radioactivity into solution and under the appropriate conditions could be applied in the field.
Methods:
Pipe scale: Scale material was obtained from casings removed from an Oklahoma oilfield (provided by Arrow Oil and Gas Inc.) and from an Alberta oil production facility (provided by Petrocan). The Oklahoma casings by beaten with a hammer to remove the scale which had become somewhat oxidized due to weathering in the field. Petrocan provided a casing section shipped directly to the University of Oklahoma. Scale material was chipped off the inside of the casing prior to use. All scale materials were ground with a mortar and pestle prior to incubation with sedimentary microorganisms or prior to geochemical analyses.
Geochemical analyses: Total reduced sulfur was determined as described by Ulrich et al. (Ulrich, 1997) and acid volatile sulfur was determined in a similar manner except that materials were extracted with anoxic 1 M HCl rather than the mix of Cr(II) and concentrated HCl.
Dissolved Barium was measured by Graphite furnace Atomic Absorbtion spectroscopy (name of instrument tom). Dissolved radioactivity was determined by counting for 100 min in a volume of 2 ml. Gamma spectra were obtained with a Germanium Lithium detector.
Scale dissolution experiments: All incubations were carried out in 120 or 160 ml serum bottles. Microbial inoculum was derived from subsurface sulfate reducing sediments collected at the Norman Landfill. 50 gm of sediments were suspended in 50 ml of mineral solution two times. The first wash was discarded and the second time, sediments were shaken with cells to dislodge them. After pouring the solution off the sediments, the second wash was used as innoculum (2 ml per bottle). Each bottle contained 2 gm of crushed pipe scale and 100 ml of mineral solution (Krumholz & Bryant, 1986).
Summary/Accomplishments (Outputs/Outcomes):
Geochemical modeling was carried out based on ions present in mineral solutions. Models were generated using PhreeqC, a code generated by the USGS. Figure 1, below shows Ba2+ dissolution as a function of carbohydrates oxidized. In this case the model was generated in
the absence of a witherite (BaCO3) solid phase. The second model (Fig. 2) was run at different starting pH values. A witherite solid phase was added to the model when witherite became saturating. Above pH 7.0 there was little additional effect of pH. This latter model showed us that pH can control reprecipitation of Ba2+ as witherite but not until concentrations reach 0.5 mM at pH 7.0.
Sediments and a mineral solution were incubated with Barite containing scale from an oilfield in Alberta. Additions were made including 20 mM FeCl2, 20 mM ethanol or a combination of the two. Over time, dissolved barium was monitored (Fig. 1). At the end of the experiment (150 days), solids were removed and suspended in 1 M HCl. Acid soluble barium was then measured to determine the barium component that had been dissolved but had reprecipitated as acid soluble material. As the majority of the scale is barite, which is not acid soluble, it makes sense that barium released due to treatment with acid was in the form of some other mineral.
Figure 4. Radioactivity released from pipe scale.
Following incubations, remaining solid phases were extracted with 1 N HCl. Radioactivity in the culture supernatant and the acid soluble material were determined and plotted (Fig. 4). These latter data show that radio activity has been released into solution following sulfate reduction activity.
Pipe scale is formed as Barite, pyrite and various carbonate minerals precipitate on the inside surface of structures associated with oil production. As these minerals are deposited, radium is co-precipitated. There is much cost associated with resultant radioactive material.
We are developing a biotechnology to dissolve scale material and release the radioactivity. The conversion of sulfate to sulfide, carried out by sulfate-reducing bacteria in conjunction with the oxidation of reduced carbon compounds can effectively draw radium and barium into solution.
We have carried out laboratory studies using microorganisms from anoxic landfill sediments. The action of these microorganisms on NORM containing pipe scale incubated in a mineral solution with ethanol as electron donor resulted in the production of sulfide and the release of Barium into solution. Under simple incubation conditions approximately 0.25 gm/L of sulfate was converted to sulfide and 33 g of barium per liter were released into solution. Under these same conditions, no methane was produced and electrons from ethanol appeared to be used to reduce sulfate exclusively. We have recently shown that the additions of more ethanol during the incubation as well as the addition of Ferrous hydroxide serves to dramatically increase the amount of Barium released into solution (42 mg/L) and most likely also increased sulfide production. However, much of the sulfide produced appears to have been incorporated into pyrite. The relatively small increase in dissolved barium relative to sulfide and pyrite present suggests that the majority of Barium has re-precipitated, perhaps as barium carbonate or barium phosphate. Studies using acid to dissolve the precipitated material at the end of the incubation show that a significant of additional barium is released into solution. This data supports the re-precipitation hypothesis. To determine whether radioactivity is also being released into solution, we measured gamma radiation associated with the dissolved phase. Radioactivity was released in proportion to the amount of dissolved barium assuming that NORM was uniformly distributed throughout the barite within the scale material.
Conclusions:
Significant levels of pipe scale and associated NORM can be dissolved by the action of sediment dwelling sulfate reducing bacteria. A large fraction of the dissolved barium and radioactivity reprecipitates as acid soluble minerals. The presence of ferrous iron increases the level of dissolution as well as the addition on ethanol as electron donor for sulfate reduction.
References:
Baldi, F., Pepi, M., Burrini, D., Kniewald, G., Scali, D. and Lanciotti, E. 1996. Dissolution of barium from barite in sewage sludges and cultures of Desulfovibrio desulfuricans. Appl. Environ. Microbiol. 62, 2398-2404.
Bolze, C. E., Malone, P. G. and Smith, M. J. 1974. Microbial mobilization of barite. Chem. Geol. 13, 141-3.
Fedorak, P. M. 1986. Microbial Release of 226Ra2+ from (Ba,Ra)SO4 Sludges from Uranium Mine Wastes. Applied and Environmental Microbiology, 262-268.
Krumholz, L. R. and Bryant, M. P. 1986. Eubacterium oxidoreducens sp. nov. requiring H2 or formate to degrade gallate, pyrogallol, phloroglucinol and quercetin. Arch. Microbiol. 144, 8-14.
Ulrich, G. A., Krumholz, L. R., Suflita, J. M. 1997. A rapid and simple method for estimating sulfate reduction activity and quantifying inorganic sulfides. Appl. Env. Microbiol. 63, 1627-1630.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this subprojectSupplemental Keywords:
Barite, sulfate-reduction, NORM., RFA, Economic, Social, & Behavioral Science Research Program, Scientific Discipline, Toxics, Waste, Water, Sustainable Industry/Business, National Recommended Water Quality, cleaner production/pollution prevention, Remediation, Sustainable Environment, Chemistry, Contaminant Candidate List, Technology for Sustainable Environment, Microbiology, Environmental Microbiology, Hazardous Waste, decision-making, New/Innovative technologies, Ecological Risk Assessment, Biology, Hazardous, 33/50, Engineering, Chemistry, & Physics, Environmental Engineering, Economics & Decision Making, naturally occurring radioactive material (NORM), detoxification, contaminants, microbial degradation, decision making, microorganisms, contaminated equipment, treatment, dissolution, disposal, anaerobic bacterium, radioactive wasteMain 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
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
Main Center: R827015
120 publications for this center
16 journal articles for this center