Scholarly Work - Center for Biofilm Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/9335
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Item Subsurface hydrocarbon degradation strategies in low- and high-sulfate coal seam communities identified with activity-based metagenomics(Springer Science and Business Media LLC, 2022-02) Schweitzer, Hannah D.; Smith, Heidi J.; Barnhart, Elliott P.; McKay, Luke J.; Gerlach, Robin; Cunningham, Alfred B.; Malmstrom, Rex R.; Goudeau, Danielle; Fields, Matthew W.Environmentally relevant metagenomes and BONCAT-FACS derived translationally active metagenomes from Powder River Basin coal seams were investigated to elucidate potential genes and functional groups involved in hydrocarbon degradation to methane in coal seams with high- and low-sulfate levels. An advanced subsurface environmental sampler allowed the establishment of coal-associated microbial communities under in situ conditions for metagenomic analyses from environmental and translationally active populations. Metagenomic sequencing demonstrated that biosurfactants, aerobic dioxygenases, and anaerobic phenol degradation pathways were present in active populations across the sampled coal seams. In particular, results suggested the importance of anaerobic degradation pathways under high-sulfate conditions with an emphasis on fumarate addition. Under low-sulfate conditions, a mixture of both aerobic and anaerobic pathways was observed but with a predominance of aerobic dioxygenases. The putative low-molecular-weight biosurfactant, lichysein, appeared to play a more important role compared to rhamnolipids. The methods used in this study—subsurface environmental samplers in combination with metagenomic sequencing of both total and translationally active metagenomes—offer a deeper and environmentally relevant perspective on community genetic potential from coal seams poised at different redox conditions broadening the understanding of degradation strategies for subsurface carbon.Item Modeling biofilm growth in the presence of carbon dioxide and water flow in the subsurface(2010-07) Ebigbo, Anozie; Helmig, Rainer; Cunningham, Alfred B.; Class, Holger; Gerlach, RobinThe concentration of greenhouse gases—particularly carbon dioxide (CO2)—in the atmosphere has been on the rise in the past decades. One of the methods which have been proposed to help reduce anthropogenic CO2 emissions is the capture of CO2 from large, stationary point sources and storage in deep geological formations. The caprock is an impermeable geological layer which prevents the leakage of stored CO2, and its integrity is of utmost importance for storage security. Due to the high pressure build-up during injection, the caprock in the vicinity of the well is particularly at risk of fracturing. Biofilms could be used as biobarriers which help prevent the leakage of CO2 through the caprock in injection well vicinity by blocking leakage pathways. The biofilm could also protect well cement from corrosion by CO2-rich brine.The goal of this paper is to develop and test a numerical model which is capable of simulating the development of a biofilm in a CO2 storage reservoir. This involves the description of the growth of the biofilm, flow and transport in the geological formation, and the interaction between the biofilm and the flow processes. Important processes which are accounted for in the model include the effect of biofilm growth on the permeability of the formation, the hazardous effect of supercritical CO2 on suspended and attached bacteria, attachment and detachment of biomass, and two-phase fluid flow processes. The model is tested by comparing simulation results to experimental data.Item Floating treatment wetlands for domestic wastewater treatment(2011-11) Faulwetter, J. L.; Burr, Mark D.; Cunningham, Alfred B.; Stewart, Frank M.; Camper, Anne K.; Stein, Otto R.Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO3-N. Complete removal of NO3-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment.Item NMR relaxation measurements of biofouling in model and geological porous media(2011-09) Codd, Sarah L.; Vogt, Sarah J.; Hornemann, Jennifer A.; Phillips, Adrienne J.; Maneval, James E.; Romanenko, K. R.; Hansen, L.; Cunningham, Alfred B.; Seymour, Joseph D.Recently 2D nuclear magnetic resonance (NMR) relaxation techniques have been able to access changes in pore structures through surface and diffusion based relaxation measurements. This research investigates the applicability of these methods for measuring pore and surface changes due to biofilm growth in various model porous systems and natural geological media. Model bead packs of various construction containing 100 lm borosilicate and soda lime glass beads were used to demonstrate how changes in the measured relaxation rates can be used to non-invasively verify and quantify biofilm growth in porous media. However significant challenges are shown to arise when trying to implement the same techniques to verify biofilm growth in a natural geological media.Item Reducing the risk of well bore leakage using engineered biomineralization barriers(2011-04) Cunningham, Alfred B.; Gerlach, Robin; Spangler, Lee H.; Mitchell, Andrew C.; Park, Saehan; Phillips, Adrienne J.If CO2 is injected in deep geological formations it is important that the receiving formation hassufficient porosity and permeability for storage and transmission and be overlain by a suitable low-permeability cap rock formation. When the resulting CO2 plume encounters a well bore, leakage may occur through various pathways in the “disturbed zone†surrounding the well casing. Gasda et al.[9], propose a method for determining effective well bore permeability from a field pressure test. If permeability results from such tests prove unacceptably large, strategies for in situ mitigation of potential leakage pathways become important. To be effective, leakage mitigation methods must block leakage pathways on timescales longer than the plume will be mobile, be able to be delivered without causing well screen plugging, and be resistant to supercritical CO2 (ScCO2) challenges. Traditional mitigation uses cement, a viscous fluid that requires a large enough aperture for delivery and that also must bond to the surrounding surfaces in order to be effective. Technologies that can be delivered via low viscosity fluids and that can effectively plug small aperture pathways, or even the porous rock surrounding the well could have significant advantages for some leakage scenarios.We propose a microbially mediated method for plugging preferential leakage pathways and/or porous media, thereby lowering the risk of unwanted upward migration of CO2, similar to thatdiscussed by Mitchell et al.[12].We examine the concept of using engineered microbial biofilms which are capable of precipitating crystalline calcium carbonate using the process of ureolysis. The resulting combination of biofilm plus mineral deposits, if targeted near points of CO2 injection, may result in the long-term sealing of preferential leakage pathways. Successful development of these biologically-based concepts could result in a CO2 leakage mitigation technology which can be applied either before CO2 injection or as a remedial measure. Results from laboratory column studies are presented which illustrate how biomineralization deposits can be developed along packed sand columns at length scales of 2.54 cm and 61 cm. Strategies for controlling mineral deposition of uniform thickness along the axis of flow are also discussed.Item Experimental observation of signature changes in bulk soil electrical conductivity in response to engineered surface CO2 leakage(2012-03) Zhou, Xiaobing; Lakkaraju, V. R.; Apple, Martha E.; Dobeck, Laura M.; Gullickson, K.; Shaw, Joseph A.; Cunningham, Alfred B.; Wielopolski, Lucian; Spangler, Lee H.Experimental observations of signature changes of bulk soil electrical conductivity (EC) due to CO2 leakage were carried out at a field site at Bozeman, Montana, to investigate the change of soil geophysical properties in response to possible leakage of geologically sequestered CO2. The dynamic evolution of bulk soil EC was measured during an engineered surface leakage of CO2 through in situ continuous monitoring of bulk soil EC, soil moisture, soil temperature, rainfall rate, and soil CO2 concentration to investigate the response of soil bulk EC signature to CO2 leakage. Observations show that: (1) high soil CO2 concentration due to CO2 leakage enhances the dependence of bulk soil EC on soil moisture. The bulk soil EC is a linear multivariate function of soil moisture and soil temperature, the coefficient for soil moisture increased from 2.111 dS for the non-leaking phase to 4.589 dS for the CO2 leaking phase; and the coefficient for temperature increased from 0.003 dS/°C for the non-leaking phase to 0.008 dS/°C for the CO2 leaking phase. The dependence of bulk soil EC on soil temperature is generally weak, but leaked CO2 enhances the dependence,(2)after the CO2 release, the relationship between soil bulk EC and soil CO2 concentration observes three distinct CO2 decay modes. Rainfall events result in sudden changes of soil moisture and are believed to be the driving forcing for these decay modes, and (3) within each mode, increasing soil CO2 concentration results in higher bulk soil EC. Comparing the first 2 decay modes, it is found that the dependence of soil EC on soil CO2 concentration is weaker for the first decay mode than the second decay mode.Item Abandoned well CO2 leakage mitigation using biologically induced mineralization: Current progress and future directions(2013-02) Cunningham, Alfred B.Methods of mitigating leakage or re-plugging abandoned wells before exposure to CO2are of high potential interest to prevent leakage of CO2 injected for geologic carbon sequestration in depleted oil and gas reservoirs where large numbers of abandoned wells are often present. While CO2resistant cements and ultrafine cements are being developed, technologies that can be delivered via low viscosity fluids could have significant advantages including the ability to plug small aperture leaks such as fractures or delamination interfaces. Additionally there is the potential to plug rock formation pore space around the wellbore in particularly problematic situations. We are carrying out research on the use of microbial biofilms capable of inducing the precipitation of crystalline calcium carbonate using the process of ureolysis. This method has the potential to reduce well bore permeability, coat cement to reduce CO2–related corrosion, and lower the risk of unwanted upward CO2 migration. In this spotlight, we highlight research currently underway at the Center for Biofilm Engineering (CBE) at Montana State University (MSU) in the area of ureolytic biomineralization sealing for reducing CO2 leakage risk. This research program combines two novel core testing systems and a 3-dimensional simulation model to investigate biomineralization under both radial and axial flow conditions and at temperatures and pressures which permit CO2 to exist in the supercritical state.This combination of modeling and experimentation is ultimately aimed at developing and verifying biomineralization sealing technologies and strategies which can successfully be applied at the field scale for carbon capture and geological storage (CCGS) projects.