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Müller, Imre

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Müller, Imre
Affiliation principale
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https://libra.unine.ch/handle/123456789/154

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  • Publication
    Métadonnées seulement
    Biocolloid and solute tracer transport in gravel aquifers - a groundwater protection perspective
    (: A a Balkema Publishers, 2001)
    Kennedy, Keith
    ;
    Schurch, Marc
    ;
    Müller, Imre 
    ;
    Vuataz, François 
    ;
    Seiler, Klaus-Peter
    ;
    Wohnlich, Stefan
    Migration conditions in a gravel aquifer of the upper Rhone River valley were studied using particle and solutes as contaminant surrogates. Transport rates were 130 to 480 m/d over distances to 22 in, up to 40 times faster than predicted using conventional flow/effective porosity parameters. In one well, a 1-m vertical pathway heterogeneity dominated the 12-m aquifer saturated thickness. Biocolloids were consistently detected earlier than solutes due in part to their significantly lower detection limits and possibly to preferential particle advection. Biocolloid detection occurred 3- to 7-times earlier than time to solute breakthrough peaks, those values commonly relied on when calculating reference velocity parameters. Relative colloid recovery was typically 1.5 to 4 percent and in one case was 72 % of the solute illustrating relatively low biocolloid attenuation in river gravel macropores. Transport direction was up to 90 degrees off those determined from head-derived measurements. Results suggest that reliable groundwater protection strategy in heterogeneous gravel aquifers may improve when field-verified with migration characterization using multiple tracer types.
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    The combined use of radio-frequency electromagnetics and radiomagnetotellurics methods in non-ideal field conditions for delineating hydrogeological boundaries and for environmental problems
    Dill Carvalho, Amélia
    ;
    Turberg, Pascal
    ;
    Müller, Imre 
    ;
    Parriaux, Aurèle
    Radio frequency geophysical methods are known for being very versatile tools in ground- and groundwater investigation at shallow depths. They are fast and easy to use and allow a high density of information over large surfaces, which makes them very suitable for geological mapping sensu lato (faults, lithological contacts, groundwater-bearing structures, vulnerability maps, and contaminant plumes) and for selecting borehole locations. Significant improvement concerning 2D and 3D modelling of the data has occurred in recent decades. However, field surveys are very seldom performed in “ideal conditions”—the lack of necessary transmitters, in the convenient direction, in order to catch the structures in E- and H-pol for modelling purposes, is not an unusual situation. The present paper shows how the use of RMT and RF-EM is nevertheless of great help and suggests different ways to explore qualitative data in different geological settings.
  • Publication
    Accès libre
    Bacteriophages as surface and ground water tracers
    Rossi, Pierre
    ;
    Dörfliger, Nathalie
    ;
    Kennedy, Keith
    ;
    Müller, Imre 
    ;
    Aragno, Michel 
    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers.
    This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some gro und water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.