Flow of Kaolinite and Sewage Suspensions in Sand and Sand-Silt: I. Accumulation of Suspension Particles1
- R. L. Uebler and
- D. Swartzendruber2
Water suspensions of kaolinite clay and sewage solids were applied to vertical columns of initially air-dry fine quartz sand and sand-silt (95% fine quartz sand and 5% quartz silt), and sand-silt initially satiated (nearly saturated) with water. Water content and suspension-particle content (bulk density) were measured at various vertical positions in the column by dual-energy gamma-ray attenuation, beginning with the application of suspension and continuing until the overall hydraulic conductivity of the column had decreased to 1 mm/hour. The attenuation technique was successful for measuring the kaolinite bulk density but was of limited value for determining the sewage-solid bulk density. By postulating a mechanism of suspension-particle entrapment within the porous medium, an exponential equation was derived to describe the accumulation of suspension particles with time at a fixed position. The constants in this equation were determined from the experimental data by nonlinear least-squares regression and appeared to offer promise for characterizing the kaolinite accumulation in the sand and sand-silt. In general, the maximum accumulation of kaolinite occurred in the several millimeters nearest the suspension-application surface. The initial water content (air-dry or satiated) had little effect on kaolinite accumulation in the sand-silt, and the detectable depth of penetration was 3 to 4 cm in both cases. In contrast, kaolinite penetration to about 16 cm was detected in the initially air-dry sand, whereas the maximum (near-surface) accumulations were larger than in the sand-silt but required much more time to attain.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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