EXPERIMENTAL-TECHNIQUES FOR LABORATORY INVESTIGATION OF CLAY COLLOID TRANSPORT AND FILTRATION IN A STREAM WITH A SAND-BED

Citation
Ai. Packman et al., EXPERIMENTAL-TECHNIQUES FOR LABORATORY INVESTIGATION OF CLAY COLLOID TRANSPORT AND FILTRATION IN A STREAM WITH A SAND-BED, Water, air and soil pollution, 99(1-4), 1997, pp. 113-122
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environmental Sciences","Water Resources
ISSN journal
0049-6979
Volume
99
Issue
1-4
Year of publication
1997
Pages
113 - 122
Database
ISI
SICI code
0049-6979(1997)99:1-4<113:EFLIOC>2.0.ZU;2-D
Abstract
The exchange of kaolinite clay between a stream and its associated san d bed was investigated in a recirculating flume. Bedforms at the sedim ent-water interface result in two bed-exchange mechanisms: the bedform shape induces an advective flow through the bed ('pumping'), and dune propagation causes the trapping and release of pore water ('turnover' ). Chemical and electrostatic interactions then result in filtration o f clay by the bed. In order to allow modeling of chemical effects, all flume materials must have defined chemical parameters. This required improvements in the flume water supply, construction of sand-washing e quipment, and the use of defined clay and sand preparation procedures. Flume experimental results indicate that clay is extensively trapped by the bed. Advective pumping tends to carry clay to the deep bed wher e it can be permanently trapped, while turnover tends to continuously mix the upper layers of the bed, hindering penetration to the deep bed .