Construction and Testing of a Durable Platinum Wire Eh Electrode for In Situ Redox Measurements in the Subsurface

Swerhone, G. D. W.; Lawrence, John R.; Richards, Justin; Hendry, M. Jim

doi:10.1111/j.1745-6592.1999.tb00214.x

Cited by 22 publications

(14 citation statements)

References 4 publications

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“…The Pt electrodes (D = 500 µm) were designed and calibrated as described in Swerhone et al (1999) with minor modifications in their configuration. A Pt wire (2.5 cm) was soldered to a copper wire (1 m), and the electrodes were introduced through the ports in a septum ensuring that their tips were centered into the 1.5 mm fracture.…”

Section: Orp Monitoringmentioning

confidence: 99%

Development and resistance of a biofilm in a planar fracture during biostimulation, starvation, and varying flow conditions

Ross¹,

Novakowski²,

Lesage³

et al. 2007

Journal of Environmental Engineering and Science

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Investigations of biofilms in a planar fracture are required to develop a biobarrier concept in aquifers. A glass-fracture apparatus was designed to monitor a biofilm under three phases: biostimulation, starvation, and increased flow. Direct observations were performed using a light probe whereas indirect indications were obtained by enumerating planktonic bacteria, monitoring the oxidation-reduction potential (ORP), and interpreting tracer experiments using an analytical model for two-dimensional advection-dispersion. Biofilm clusters developed along the flow lines before extending to a fully-connected biofilm, covering 500 cm 2 after 50 d. The starvation phase favoured bacterial attachment at first followed by detachment, which was accentuated by increases in groundwater velocity. The ORP declined over the three experimental phases and was significantly related to the distance from the biostimulation zone. The modeling suggested that an increase in transverse dispersion within the fracture only occurs during the biostimulation phase.Résumé : Les études sur les biofilms dans une fracture en plan sont requises pour développer un concept de barrières biologiques dans les aquifères. Un appareil en verre, imitant ce plan de fracture, a été conçu pour surveiller le biofilm sous trois phases : biostimulation, privation et écoulement accru. Des observations directes ont été réalisées en utilizant une sonde lumineuse alors que des observations indirectes ont été obtenues par l'énumération des bactéries planctoniques, la surveillance du potentiel d'oxydoréduction et l'interprétation d'expériences avec traceur au moyen d'un modèle analysant l'advection-diffusion en deux dimensions. Des grappes de biofilms se sont accumulées le long des lignes d'écoulement avant de se propager pour former un biofilm entièrement interconnecté, couvrant 500 cm 2 après 50 jours. La phase de privation favorisait la fixation des bactéries en premier, suivi d'un détachement qui a été accentué par l'augmentation de la vitesse de l'écoulement souterrain. Le potentiel d'oxydoréduction a diminué au cours des trois phases expérimentales et était grandement fonction de la distance de la zone de biostimulation. La modélisation a suggéré qu'une augmentation dans la diffusion transversale dans la fracture ne soit survenue que durant la phase de biostimulation.

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Section: Orp Monitoringmentioning

confidence: 99%

Development and resistance of a biofilm in a planar fracture during biostimulation, starvation, and varying flow conditions

Ross¹,

Novakowski²,

Lesage³

et al. 2007

Journal of Environmental Engineering and Science

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“…A micro‐pH electrode and ISEs for Cl − , Ca 2+ , Na + , and K + were used with a common reference electrode and connected to an ORION voltmeter via a switch box. A micro‐Eh electrode was constructed using the modified method of Swerhone et al (1999). Reliable results were obtained by minimizing electrode interference and iterative calibration with selected samples ( n = 13) analyzed by ion chromatography (IC), which also included determination of SO 4 2− concentrations.…”

Section: Experimental Methodsmentioning

confidence: 99%

Long‐Term Reactive Solute Transport in an Aquitard Using a Centrifuge Model

Timms

Hendry

2008

Groundwater

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Characterizing and predicting reactive solute transport in low hydraulic conductivity (K) clay-rich media is challenging because the very long transport time for solutes renders conventional column tests impractical. In this study, a centrifugation technique was developed to assess the transport of a simple aqueous solution (NaCl) by accelerating flow by centrifugal force through low K (1.1 x 10(-11) m/s) core samples. Duplicate cores (52-mm length x 33-mm diameter) were centrifuged at 330 xg for 90 d to model the migration of saline pore water (0.5 M NaCl) under in situ conditions through an approximately 17-m-thick clay prototype over approximately 24,000 years. A PHREEQC one-dimensional reactive solute transport code simulated effluent breakthrough of the NaCl during centrifugation, with best-fit cation exchange coefficients similar to batch tests. The calibrated code was used to predict solute profile development over the long term in the prototype or simulated field-scale conditions. Chromatographic separation of solutes due to ion exchange was evident over several meters in the simulated prototype and the field profile. The applicability of centrifugation methods to predict transport of more complex suites of reactive solutes over the long term is yet to be verified.

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“…To define the initial conditions in the well environment (prior to the application of impressed current), redox potential (Eh) was monitored with depth using an in situ network of platinum wire mini-electrodes (Swerhone et al, 1999) installed near the research production wells on the outside of the casing, with data collected on-site using a high-impedance data logger (Campbell Scientific, Inc. North Logan, UT; data not shown). Physicochemical data was obtained for ground water collected from piezometers installed at various distances between the river and the wells (Table 1) and iron and manganese concentrations were measured for sediment cores and biofilm coupons collected near the production wells.…”

Section: Sample Collectionmentioning

confidence: 99%

Transient response of microbial communities in a water well field to application of an impressed current

et al. 2013

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Construction and Testing of a Durable Platinum Wire Eh Electrode for In Situ Redox Measurements in the Subsurface

Cited by 22 publications

References 4 publications

Development and resistance of a biofilm in a planar fracture during biostimulation, starvation, and varying flow conditions

Development and resistance of a biofilm in a planar fracture during biostimulation, starvation, and varying flow conditions

Long‐Term Reactive Solute Transport in an Aquitard Using a Centrifuge Model

Transient response of microbial communities in a water well field to application of an impressed current

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