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RECORD NUMBER: 168 OF 516

OLS Field Name OLS Field Data
Main Title Flocculation of Fine-Grained Lake Sediments Due to a Uniform Shear Stress.
Author Tsai, C. H. ; Iacobellis, S. ; Lick, W. ;
CORP Author California Univ., Santa Barbara. Dept. of Mechanical and Environmental Engineering.;Environmental Research Lab.-Duluth, MN.
Publisher c1987
Year Published 1987
Report Number EPA-R-005796; EPA/600/J-87/526;
Stock Number PB90-264995
Additional Subjects Agglomeration ; Sediments ; Shear stress ; Flocculating ; Suspended sediments ; Fines ; Particle size distribution ; Concentration(Composition) ; Lake Erie ; Water pollution ; Sediment transport ; Experimental design ; Reprints ; Environmental transport ; Sediment-water interfaces
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB90-264995 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 12/03/1990
Collation 13p
Abstract
Experiments were performed to investigate the effects of fluid shear on the flocculation of fine-grained lake sediments in fresh water. In these experiments, a Couette viscometer was used to apply a uniform shear stress to a sediment suspension. The sediments were from the Detroit River inlet of Lake Erie. They were prepared such that the initial (unflocculated) size distribution contained approximately 90% of its mass in particles less than 10 micrometers in diameter with the average diameter being about 3.5 micrometers. Experiments were performed at shear stresses of 1, 2, and 4 dynes/sq cm and sediment concentrations of 50, 100, 400, and 800 mg/L, values which are characteristic of those found in the Great Lakes. Data in the form of floc size distribution as a function of time were obtained. For steady-state conditions, the median diameters of the flocs formed were typically 20 to 100 micrometers depending on shear stress and sediment concentration. Quantitative results for the decrease in the steady-state floc size with increasing shear stress and with increasing sediment concentration were obtained. The times required for flocculation to occur under different conditions were also determined and were typically on the order of 1 hour.