Flow dynamics and potential for biodegradation of organic contaminants in fractured rock vadose zones

Geller, Jil T.; Holman, Hoi‐Ying N.; Su, Grace W.; Conrad, Mark E.; Pruess, Karsten; Hunter-Cevera, Jennie

doi:10.1016/s0169-7722(99)00095-9

Cited by 33 publications

(21 citation statements)

References 43 publications

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“…UV fluorescence was also shown to be an effective way of examining not merely mineral variations within a rock, but also fracture planes. Fractures are important features from the point of habitability as they provide access points for exogenous delivery of nutrients, energy supplies and water and they can provide surfaces on which microorganisms can grow (Pedersen 1997;Geller et al 2000;Cockell et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

Payler

Biddle

Coates

et al. 2016

International Journal of Astrobiology

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Abstract. The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research -MINAR (MINe Analog Research). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator (AUPE-2), Close-Up Imager (CLUPI), Raman Spectrometer, SPLIT (Small Planetary Linear Impulse Tool), Ultrasonic Drill and handheld XRD. We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimeter to meter scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining. IntroductionPlanetary analog research involves the investigation of terrestrial environments that are comparable to extraterrestrial environments. These analogs tend to be focused, at a high level, on science, science operations, or technology research and testing, or a combination of these topics (e.g. Dickinson and Rosen 2003;Sarrazin et al. 2005; Cabrol et al. 2007;Pollard et al. 2009; Lim et al. 2011;Abercromby et al. 2013). Analog field settings are used to evaluate scientific instruments of particular relevance to future flight missions in a rugged field setting. These field tests have, for example, ranged from deserts to underwater settings (e.g. Cabrol et al. 2007;Jasiobedzki et al. 2012;Abercromby et al. 2013), and have taken a variety of forms, from testing a single technology to examine its performance in a particular environment (e.g. Skelley et al. 2007), to fully integrated rover tests utilizing a variety of different instruments (e.g. Schenker et al. 2001).One environment that has received less attention for analog research, but which holds a great deal o...

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Section: Discussionmentioning

confidence: 99%

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

Payler

Biddle

Coates

et al. 2016

International Journal of Astrobiology

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“…The Watershed and AccuGen polymers were relatively hydrophobic. The Watershed polymer had a contact angle of 81.6 Ϯ 1.3°, which was greater than that of the epoxy models (57 to 65°) used by Geller et al (11). The AccuGen polymer had a contact angle of 45.3 Ϯ 9.9°.…”

Section: Resultsmentioning

confidence: 80%

“…Microbial colonization and calcite deposition enhanced the stagnant regions adjacent to solid boundaries. Microbial growth and calcite precipitation occurred to a greater extent in areas behind the fabricated obstacles and less in high-velocity orifices.Understanding the mechanisms by which microorganisms affect fluid flow in groundwater and subsurface environments is significant because of the importance of natural geohydrological processes (41), understanding the transport of microorganisms in the subsurface (12, 23), mitigating contaminant transport in the subsurface (12), and utilizing microorganisms for in situ processes such as mineral dissolution and recovery (3, 4, 7), enhanced oil recovery (15, 48), and contaminant remediation (11,13,39,40). Microorganisms are only one of the interacting physical, chemical, and biological variables that can affect the behavior of fluid flow in subsurface systems.…”

mentioning

confidence: 99%

Application of Stereolithographic Custom Models for Studying the Impact of Biofilms and Mineral Precipitation on Fluid Flow

Stoner¹,

Watson²,

Stedtfeld³

et al. 2005

Appl Environ Microbiol

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Here we introduce the use of transparent experimental models fabricated by stereolithography for studying the impacts of biomass accumulation, minerals precipitation, and physical configuration of flow paths on liquid flow in fracture apertures. The internal configuration of the models ranged in complexity from simple geometric shapes to those that incorporate replicated surfaces of natural fractures and computationally derived fracture surfaces. High-resolution digital time-lapse imaging was employed to qualitatively observe the migration of colloidal and soluble dyes through the flow models. In this study, a Sphingomonas sp. and Sporosarcina (Bacillus) pasteurii influenced the fluid dynamics by physically altering flow paths. Microbial colonization and calcite deposition enhanced the stagnant regions adjacent to solid boundaries. Microbial growth and calcite precipitation occurred to a greater extent in areas behind the fabricated obstacles and less in high-velocity orifices.Understanding the mechanisms by which microorganisms affect fluid flow in groundwater and subsurface environments is significant because of the importance of natural geohydrological processes (41), understanding the transport of microorganisms in the subsurface (12, 23), mitigating contaminant transport in the subsurface (12), and utilizing microorganisms for in situ processes such as mineral dissolution and recovery (3, 4, 7), enhanced oil recovery (15, 48), and contaminant remediation (11,13,39,40). Microorganisms are only one of the interacting physical, chemical, and biological variables that can affect the behavior of fluid flow in subsurface systems. One of the greatest challenges in understanding and computationally simulating subsurface hydrogeological processes is the influence of microbial exudates and biofilm accumulation on liquid flow in fractures and porous geomatrices.Experimental models have been utilized extensively to study multiphase flow phenomena (16,19,26,47) in porous media and their effects on colloids (34, 47) and to study the mechanisms responsible for biomass plugging in porous media (17,36,37). Models are frequently used to examine the impact of biofilm formation on surface chemistry, materials degradation, fluid flow, and surface corrosion (25, 42). The impacts of surface topography, substratum composition, and fluid properties on bacterial adhesion, colonization, detachment, activity, and interactions among community members (24,32,35,43) have also been examined using experimental models.In many studies, experimental models with relatively simple geometries were fabricated by machining or glass etching (6, 32). However, these approaches cannot easily be applied to the fabrication of complex three-dimensional (3-D) models designed to examine the impact of microbial processes on fluid flow in subsurface fractures. Machining of complex cavities that bear a resemblance to natural fractures and porous media is difficult. Because of limited machine tolerances, it is often not possible to obtain reproducible results ...

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“…Equation 1 does not account for the capillary pressure at the DNAPL-air interface because it assumes a capillary pressure of zero at that interface, which is valid in locations where the DNAPL flow above the lens is continuous and occurs as gravity-driven flow. When the flux of the DNAPL into the fracture is low, the DNAPL may flow in an intermittent manner ( Figure 1b), where the DNAPL flows as a series of discontinuous blobs (Geller et al, 2000). Under conditions when the flow channel is discontinuous, Equation 1 may not apply because the capillary force at the DNAPL-air interface must also be accounted for when calculating the critical entry height.…”

Section: Criteria For Entry Of Napl Into the Watermentioning

confidence: 99%

“…Aside from the initial studies conducted by Schwille (1988) and more recent experiments conducted by Geller et al (2000), most of the research examining DNAPLs in fractures has been focused on saturated fractures. Since leakage and spills of DNAPLs typically occur in the unsaturated zone, understanding the flow and distribution of DNAPLs in unsaturated fractures is also critical.…”

Section: Introductionmentioning

confidence: 99%

DNAPL invasion into a partially saturated dead-end fracture

gov¹

2004

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The critical height for DNAPL entry into a partially water saturated, dead-end fracture is derived and compared to laboratory observations. Experiments conducted in an analog, parallel-plate fracture demonstrate that DNAPL accumulates above the water until the height of the DNAPL overcomes the sum of the capillary forces at the DNAPL-air interface and at the DNAPL-water interface. These experiments also show that DNAPL preferentially enters the water at locations where DNAPL has previously entered, and the entry heights for these subsequent entries are lower than the heights measured for the initial invasion. The wetting contact angle at the DNAPL-water interface becomes larger at the locations where the DNAPL has already entered the water because of residual DNAPL on the fracture walls, which results in lowering the critical entry height at those locations. The experiments also demonstrate that a DNAPL lens can remain nearly immobile above the water for a period of time before eventually redistributing itself and entering the water.2

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Flow dynamics and potential for biodegradation of organic contaminants in fractured rock vadose zones

Cited by 33 publications

References 43 publications

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

Application of Stereolithographic Custom Models for Studying the Impact of Biofilms and Mineral Precipitation on Fluid Flow

DNAPL invasion into a partially saturated dead-end fracture

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