Recovery and concentration of suspended solids in the upper rhone river by continuous flow centrifugation

Abstract

Six stations along the RhBne River from the RhBne Glacier to Lake Geneva were sampled by continuous flow centrifuge for recovery of suspended sediment. The samples were taken four times in the year in both 1982 and 1983. In addition, the mouth of the river was sampled in a like manner every two weeks during 1982 until August 1983. Concentration of sediment and composition did not vary as a function of depth or location across the river. Concentrations varied in time and as a function of flow and samples showed both increasing concentration in suspension and an increase in the proportion of finer particles moving downstream from source to mouth. Only slight variations in texture could be observed down the river as a function of time and appeared to relate to freezing and melting of the RhBne and other headwater glaciers as the primary sediment source. Little variation was observed annually in the texture and composition of the sediment at the river mouth despite large changes in concentration between the high flow summer and low flow winter discharges. These findings are consistent with a well-mixed system in which the suspended sediments are directly related to the primary supply of material from the glaciers.

Particle size characteristics of suspended and bed sediments in the rhône river

“…, and one coarser at 396pm. These values agree well with data from Burrus (1989) and Santiago (unpublished) on longer-term sampling. The coarse sands transported in suspension or by saltation are moving as a result of the high hydrodynamic energy of the glacial waters and probably in conjunction with some resuspension due to gravel pits.…”

Comparative ecotoxicity of suspended sediment in the lower Rhone River using algal fractionation, Microtox® and Daphnia magna bioassays

“…This was necessary to provide sufficient sediment to carry out the total array of analyses required in the collaborative study. The efficiency of particle separation in these centrifuges is known to be greater than 90% of the incoming suspended sediment (McMillan & Thomas, 1977;Ongley & Blachford, 1982;Horowitz et al, 1989;Ongley & Thomas, 1989;Burrus et al, 1989). A comparative evaluation of the two centrifuges utilized indicates high similarity in the performance of both machines, which show comparable grain size distributions and heavy metal concentrations for the collected suspended solids (Santiago et al, 1990). Sediments were collected at 9 locations.…”

Comparison of Different Monitoring Programs of the 2002 Summer Flood in the River Elbe

“…Investigations showed that the flow centrifuge Padberg Z61 (17 000 U/min) recovers 93 % of the suspended solids [16] in comparison to a filtration (0.45 μm pore width). Burrus et al [17] demonstrated that 97 % of the suspended solids could be recovered with Westfalia centrifuge compared to 0.45-μm filtration.…”