Settling behavior of fine-grained materials in flocs

This paper contributes to the understanding of the effect of suspended sediment deposition and turbidity on aquatic systems. The influence of the cohesive properties of clay on its settling behaviour was quantified in still distilled water with ion addition. Two different model materials, alumina and quartz, were used, as their identical presentation in the mineral composition of clay affects the flocculation of suspended fine particles. The suspended concentrations were measured in a 1m settling column using a CCD Camera. The settling rates of alumina and quartz increased with salinity, with the settling rates for alumina being higher than those for quartz at any given salinity. The settling velocities for alumina were higher at pH 9, whereas the opposite was true for quartz. Conversely, the settling velocities for quartz were higher at pH 4, while the velocities for alumina were then low.