Browsing by Author "Hiebert, Dwight Randall"

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Biofilm detection in a model well-bore environment using low-field magnetic resonance
(2015-09) Kirkland, Catherine M.; Hiebert, Dwight Randall; Phillips, Adrienne J.; Grunewald, Elliot; Walsh, David O.; Seymour, Joseph D.; Codd, Sarah L.
This research addresses the challenges of the lack of non-invasive methods and poor spatiotemporal resolution associated with monitoring biogeochemical activity central to bioremediation of subsurface contaminants. Remediation efforts often include growth of biofilm to contain or degrade chemical contaminants, such as nitrates, hydrocarbons, heavy metals, and some chlorinated solvents. Previous research indicates that nuclear magnetic resonance (NMR) is sensitive to the biogeochemical processes of biofilm accumulation. The current research focuses on developing methods to use low-cost NMR technology to support in situ monitoring of biofilm growth and geochemical remediation processes in the subsurface. Biofilm was grown in a lab-scale radial flow bioreactor designed to model the near wellbore subsurface environment. The Vista Clara Javelin NMR logging device, a slim down-the-borehole probe, collected NMR measurements over the course of eight days while biofilm was cultivated in the sand-packed reactor. Measured NMR mean log T2 relaxation times decreased from approximately 710 to 389 ms, indicating that the pore environment and bulk fluid properties were changing due to biofilm growth. Destructive sampling employing drop plate microbial population analysis and scanning electron and stereoscopic microscopy confirmed biofilm formation. Our findings demonstrate that the NMR logging tool can detect small to moderate changes in T2 distribution associated with environmentally relevant quantities of biofilm in quartz sand.
Biofilm enhanced subsurface sequestration of supercritical CO2
(2009-01) Mitchell, Andrew C.; Phillips, Adrienne J.; Hiebert, Dwight Randall; Gerlach, Robin; Cunningham, Alfred B.
In order to develop subsurface CO2 storage as a viable engineered mechanism to reduce the emission of CO2 into the atmosphere, any potential leakage of injected supercritical CO2 (SC-CO2) from the deep subsurface to the atmosphere must be reduced. Here, we investigate the utility of biofilms, which are microorganism assemblages firmly attached to a surface, as a means of reducing the permeability of deep subsurface porous geological matrices under high pressure and in the presence of SC-CO2, using a unique high pressure (8.9 MPa), moderate temperature (32 Â°C) flow reactor containing 40 millidarcy Berea sandstone cores. The flow reactor containing the sandstone core was inoculated with the biofilm forming organism Shewanella fridgidimarina. Electron microscopy of the rock core revealed substantial biofilm growth and accumulation under high-pressure conditions in the rock pore space which caused >95% reduction in core permeability. Permeability increased only slightly in response to SC-CO2 challenges of up to 71 h and starvation for up to 363 h in length. Viable population assays of microorganisms in the effluent indicated survival of the cells following SC-CO2 challenges and starvation, although S. fridgidimarina was succeeded by Bacillus mojavensis and Citrobacter sp. which were native in the core. These observations suggest that engineered biofilm barriers may be used to enhance the geologic sequestration of atmospheric CO2.
Biofilm process in porous media - practical applications
(1997) Cunningham, Alfred B.; Warwood, B. K.; Sturman, Paul J.; Horrigan, K.; James, Garth A.; Costerton, J. William; Hiebert, Dwight Randall
Decarboxylation and hydrogenation of safflower and rapeseed oils and soaps to produce diesel fuels
(Montana State University - Bozeman, College of Engineering, 1985) Hiebert, Dwight Randall
Design of a meso-scale high pressure vessel for the laboratory examination of biogeochemical subsurface processes
(2015-02) Phillips, Adrienne J.; Eldring, Joseph; Hiebert, Dwight Randall; Lauchnor, Ellen G.; Mitchell, Andrew C.; Cunningham, Alfred B.; Spangler, Lee H.; Gerlach, Robin
Biocides are critical components of hydraulic fracturing (â€œfrackingâ€ ) fluids used for unconventional shale gas development. Bacteria may cause bioclogging and inhibit gas extraction, produce toxic hydrogen sulfide, and induce corrosion leading to downhole equipment failure. The use of biocides such as glutaraldehyde and quaternary ammonium compounds has spurred a public concern and debate among regulators regarding the impact of inadvertent releases into the environment on ecosystem and human health. This work provides a critical review of the potential fate and toxicity of biocides used in hydraulic fracturing operations. We identified the following physicochemical and toxicological aspects as well as knowledge gaps that should be considered when selecting biocides: (1) uncharged species will dominate in the aqueous phase and be subject to degradation and transport whereas charged species will sorb to soils and be less bioavailable; (2) many biocides are short-lived or degradable through abiotic and biotic processes, but some may transform into more toxic or persistent compounds; (3) understanding of biocidesâ€™ fate under downhole conditions (high pressure, temperature, and salt and organic matter concentrations) is limited; (4) several biocidal alternatives exist, but high cost, high energy demands, and/or formation of disinfection byproducts limits their use. This review may serve as a guide for environmental risk assessment and identification of microbial control strategies to help develop a sustainable path for managing hydraulic fracturing fluids.
Fracture Sealing with Microbially-Induced Calcium Carbonate Precipitation: A Field Study
(2016-04) Phillips, Adrienne J.; Cunningham, Alfred B.; Gerlach, Robin; Hiebert, Dwight Randall; Hwang, Chiachi; Lomans, B. P.; Westrich, Joseph; Mantilla, C.; Kirksey, J.; Esposito, R.; Spangler, Lee H.
A primary environmental risk from unconventional oil and gas development or carbon sequestration is subsurface fluid leakage in the near wellbore environment. A potential solution to remediate leakage pathways is to promote microbially induced calcium carbonate precipitation (MICP) to plug fractures and reduce permeability in porous materials. The advantage of microbially induced calcium carbonate precipitation (MICP) over cement-based sealants is that the solutions used to promote MICP are aqueous. MICP solutions have low viscosities compared to cement, facilitating fluid transport into the formation. In this study, MICP was promoted in a fractured sandstone layer within the Fayette Sandstone Formation 340.8 m below ground surface using conventional oil field subsurface fluid delivery technologies (packer and bailer). After 24 urea/calcium solution and 6 microbial (Sporosarcina pasteurii) suspension injections, the injectivity was decreased (flow rate decreased from 1.9 to 0.47 L/min) and a reduction in the in-well pressure falloff (>30% before and 7% after treatment) was observed. In addition, during refracturing an increase in the fracture extension pressure was measured as compared to before MICP treatment. This study suggests MICP is a promising tool for sealing subsurface fractures in the near wellbore environment.
In situ biofilm barriers: Case study of a nitrate groundwater plume, Albuquerque, New Mexico
(2005) Dutta, Lomesh; Nuttall, H. Eric; Cunningham, Alfred B.; James, Garth A.; Hiebert, Dwight Randall
A new use for biofilm barriers was developed and successfully applied to treat nitrate-contaminated groundwater down to drinking water standards. The barrier was created by stimulating indigenous bacteria with injections of molasses as the carbon donor and a combination of yeast extract and trimetaphosphate as nutrients. This injection of amendments results in bacterial growth in the aquifer, which attaches to the sand grains to create a reactive semipermeable biofilm. The biofilm barrier presented in this article reduced the migration of contaminants and provided an active zone for remediation. The cylindrical biobarrier was constructed using eight wells on the perimeter forming a 60-foot-diameter reactive biodenitrification region. Another well at the center was installed to continuously extract the treated water. The intent was to produce a continuous source of nitrate-free water. The system operated for over one year, and during this period, the biobarrier was revived multiple times by reinjecting molasses in the perimeter wells. Nitrate concentrations of treated water decreased from 275 mg/L (as nitrogen) to <1 mg/L.
In situ detection of subsurface biofilm using low-field NMR: A field study
(2015-09) Kirkland, Catherine M.; Herrling, M. P.; Hiebert, Dwight Randall; Bender, A. T.; Grunewald, Elliot; Walsh, David O.; Codd, Sarah L.
Subsurface biofilms are central to bioremediation of chemical contaminants in soil and groundwater whereby micro-organisms degrade or sequester environmental pollutants like nitrate, hydrocarbons, chlorinated solvents and heavy metals. Current methods to monitor subsurface biofilm growth in situ are indirect. Previous laboratory research conducted at MSU has indicated that low-field nuclear magnetic resonance (NMR) is sensitive to biofilm growth in porous media, where biofilm contributes a polymer gel-like phase and enhances T2 relaxation. Here we show that a small diameter NMR well logging tool can detect biofilm accumulation in the subsurface using the change in T2 relaxation behavior over time. T2 relaxation distributions were measured over an 18 day experimental period by two NMR probes, operating at approximately 275 kHz and 400 kHz, installed in 10.2 cm wells in an engineered field testing site. The mean log T2 relaxation times were reduced by 62% and 43%, respectively, while biofilm was cultivated in the soil surrounding each well. Biofilm growth was confirmed by bleaching and flushing the wells and observing the NMR signal’s return to baseline. This result provides a direct and noninvasive method to spatiotemporally monitor biofilm accumulation in the subsurface.
Microbial barriers to the spread of pollution
(2000) James, Garth A.; Warwood, B. K.; Hiebert, Dwight Randall; Cunningham, Alfred B.
Contamination of groundwater with toxic and carcinogenic compounds is a serious concern for public health and environmental quality. This problem is commonly manifested as a contaminant plume migrating in the direction of groundwater flow from a point source. Containment of the contaminant plume is important for preventing further migration and localizing the plume for in situ or ex situ remediation. Current containment methods include sheet pilings and grout curtains. These abiotic barriers require extensive physical manipulation of the site (e.g. excavation and back-filling) and are expensive to construct. An alternative approach, biobarrier technology, involves the use of microbial biomass produced in situ to manipulate groundwater flow (Figure 1). Biobarriers promise to be more cost effective and cause less surface disruption then conventional barrier technologies. Furthermore, containment using biobarriers can be combined with in situ biodegradation or biosequestration. This chapter will review published research that relates to biobarrier formation and present results from a mesocosm test of biobarrier longevity. These results demonstrate the effectiveness of microbial barriers for manipulation of hydraulics in mesoscale porous medium reactors.
Subsurface biofilm barriers for contaminated ground water containment
(2000-06) Cunningham, Alfred B.; Hiebert, Dwight Randall
Biofilm barriers are developed by injecting large numbers of mucoid bacteria into permeable strata formations. The bacteria are mixed with water and pumped down a series of injection wells. A suitable growth substrate and additional nutrients then are injected to stimulate microbial growth. These mucoid bacteria are capable of forming large quantities of extracellular polymer material (EPS) during their growth phase. Bacterial growth and EPS production form microbial biomass which substantially reduces the free pore space in the formation and consequently reduces the hydraulic conductivity. This zone of reduced hydraulic conductivity serves as a novel barrier technology for controlling off-site migration of mobile contaminants. Biobarrier technology also may be a useful means of funneling contaminated ground water through subsurface treatment systems (i.e., zero-valent iron systems). The main advantages offered by biobarrier technology are: 1) biobarrier construction is achieved without excavation and therefore will be economically attractive at many sites; and 2) there is no obvious depth limitation for biobarrier technology. Traditional subsurface barrier technologies such as slurry walls and grout curtains are not usually cost effective at depths more than 50 feet.
Subsurface biofilm barriers for the containment and remediation of contaminated groundwater
(2003-07) Cunningham, Alfred B.; Sharp, Robert R.; Hiebert, Dwight Randall; James, Garth A.
An engineered microbial biofilm barrier capable of reducing aquifer hydraulic conductivity while simultaneously biodegrading nitrate has been developed and tested at a field-relevant scale. The 22-month demonstration project was conducted at the MSE Technology Applications Inc. test facility in Butte, Montana, which consisted of a 130 ft wide, 180 ft long, 21 ft deep, polyvinylchloride (PVC)-lined test cell, with an initial hydraulic conductivity of 4.2 x 10-2 cm/s. A flow field was established across the test cell by injecting water up-gradient while simultaneously pumping from an effluent well located approximately 82 ft down gradient. A 30 ft wide biofilm barrier was developed along the centerline of the test cell by injecting a starved bacterial inoculum of Pseudomonas fluorescens strain CPC211a, followed by injection of a growth nutrient mixture composed of molasses, nitrate, and other additives. A 99% reduction of average hydraulic conductivity across the barrier was accomplished after three months of weekly or bi-weekly injections at intervals ranging from three to ten months. After the barrier was in place, a sustained concentration of 100 mg/l nitrate nitrogen, along with a 100 mg/l concentration of conservative (chloride) tracer, was added to the test cell influent over a six-month period. At the test cell effluent the concentration of chloride increased to about 80 mg/l while the effluent nitrate concentration varied between 0.0 and 6.4mg/l.