HR: 1340h
AN: H23E-1466    [Abstracts]
TI: Experimental Investigation of Clogging Processes in sandy aquifers Near Water Supply Wells, using X-ray Chromatography
AU: * de Zwart, B
EM: a.h.dezwart@citg.tudelft.nl
AF: TU Delft, Applied Earth Sciences, Dietzlab, mijnbouwstraat 120, Delft, 2628RX Netherlands
AU: Schotting, R
EM: schotting@geo.uu.nl
AF: University of Utrecht, Environmental Hydrogeology Group, P.O. Box 80021, Utecht, 3508TA Netherlands
AU: Hassanizadeh, M
EM: hassanizadeh@geo.uu.nl
AF: University of Utrecht, Environmental Hydrogeology Group, P.O. Box 80021, Utecht, 3508TA Netherlands
AB: In the Netherlands water supply companies produce over more than one billion cubic meters of drinking water every year. About 2500 water wells are used to pump up the groundwater from aquifers in the Dutch subsurface. More than 50% of these wells will encounter a number of technical problems during their lifetime. The main problem is the decrease in capacity due to well clogging, which results in extra, expensive cleaning operations and early replacement of the pumping wells. Well clogging is the result of a number of particle deposition mechanisms creating a complex problem in the subsurface. Investigations on mechanical processes are focused on transport of small particles through pores and deposition of particles due to physical or physio-chemical processes. The accumulation of particles due to deposition cause plugging of pores and decrease the permeability of the medium. This results in a damaged zone near the well. This study involves an experimental investigation on particle retainment in a converging geometry that simulates flow towards a well. Three parameters are varied to study the effect on deposition, flow velocity, particle concentration and aspect ration. The experiments are performed with unconsolidated material e.g. sand. During the experiment, a hematite particle suspension is fed into the sand pack to observe clogging effects. With the aid of a CT-scanner (x-ray tomography), deposition profiles in time are obtained. Also effluent particle concentrations and pressure profiles are measured online during the experiments. The results of the 10 experiments will be presented and an interpretation using deep bed filtration theory will be shown.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: Fall Meeting 2005