Use of tracer tests to investigate changes in flow and transport properties due to bioclogging of porous media

Seifert, Dorte; Engesgaard, Peter

doi:10.1016/j.jconhyd.2007.01.014

Cited by 96 publications

(95 citation statements)

References 30 publications

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“…The cell densities also increased with depth. This can be attributed to the downward migration of micro-organisms as a result of cell detachment and fluid flow (Chiume et al, 2012;Seifert and Engesgaard, 2007). As was identified with respect to the PLS cell counts, this parallels the increased wetness of the ore bed in the lateral and downward direction as a function of time.…”

Section: Bioleaching Performancementioning

confidence: 61%

“…zones A, D, E, G and H. On all three measurement days the highest cell densities were found below the irrigation point on the left vertical region of the bed (zones A, D and G) which is similar to the movement of cells reported by Yarwood et al (2006) in their studies of microbial growth in unsaturated sand beds. This can be attributed to a higher degree of liquid-mineral contacting in these regions as result of the preferential distribution of micro-organisms near the point source of irrigation, as found by Seifert and Engesgaard (2007) in their studies of bioclogging, and along the preferential flow paths evidenced by the moisture content data (Decker and Tyler, 1999;O'Kane Consultants Inc., 2000;Rossi, 1990). The cell densities also increased with depth.…”

Section: Bioleaching Performancementioning

confidence: 92%

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MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

et al. 2014

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Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg "ore slice" were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance.

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Section: Bioleaching Performancementioning

confidence: 61%

Section: Bioleaching Performancementioning

confidence: 92%

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

et al. 2014

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“…where m p for acetate and bromide can be estimated using Equation 6 and m a (x) can be estimated for acetate and bromide at monitoring wells using Equation 8.…”

Section: Apparent Mass Estimationmentioning

confidence: 99%

Feedbacks Between Hydrological Heterogeneity and Bioremediation Induced Biogeochemical Transformations

Englert

Hubbard

Williams

et al. 2009

Environ. Sci. Technol.

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For guiding optimal design and interpretation of in-situ treatments that strongly perturb subsurface systems, knowledge about the spatial and temporal patterns of mass transport and reaction intensities are important. Here, a procedure was developed and applied to time-lapse concentrations of a conservative tracer (bromide), an injected amendment (acetate) and reactive species (iron(II), uranium(VI) and sulfate) associated with two field scale biostimulation experiments, which were conducted successively at the same field location over two years. The procedure is based on a temporal moment analysis approach that relies on a streamtube approximation. The study shows that biostimulated reactions can be considerably influenced by subsurface hydrological and geochemical heterogeneities: the delivery of bromide and acetate and the intensity of the sulfate reduction is interpreted to be predominantly driven by the hydrological heterogeneity, while the intensity of the iron reduction is interpreted to be primarily controlled by the geochemical heterogeneity. The intensity of the uranium(VI) reduction appears to be impacted by both the hydrological and geochemical heterogeneity.Finally, the study documents the existence of feedbacks between hydrological heterogeneity and remediation-induced biogeochemical transformations at the field scale, particularly the development of precipitates that may cause clogging and flow rerouting.

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“…This modeling work is a step forward to devising 1 Introduction overall capacity for biodenitrification. Furthermore, the spatial heterogeneity of hydraulic 89 properties caused by the inhomogeneous distribution of biofilm throughout the porous 90 media also promotes changes in dispersivity (Seifert and Engesgaard, 2007). Dispersivity is 91 an important parameter as it affects the mixing of nitrate with injected organic substrate, 92 and it is sometimes the limiting factor for the reaction processes (Dentz et al, 2011).…”

mentioning

confidence: 99%

Modeling long term Enhanced in situ Biodenitrification and induced heterogeneity in column experiments under different feeding strategies

Rodríguez‐Escales

Folch

Breukelen

et al. 2016

Journal of Hydrology

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Use of tracer tests to investigate changes in flow and transport properties due to bioclogging of porous media

Cited by 96 publications

References 30 publications

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

Feedbacks Between Hydrological Heterogeneity and Bioremediation Induced Biogeochemical Transformations

Modeling long term Enhanced in situ Biodenitrification and induced heterogeneity in column experiments under different feeding strategies

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