CHAI Zhaohui, FANG Hongwei, WANG Xi, LIU Tonghuan, SONG Yunhao. Effect of flow and electrolyte on the flocculation-settling of cohesive sediment[J]. Advances in Water Science, 2017, 28(2): 285-292. DOI: 10.14042/j.cnki.32.1309.2017.02.014
Citation: CHAI Zhaohui, FANG Hongwei, WANG Xi, LIU Tonghuan, SONG Yunhao. Effect of flow and electrolyte on the flocculation-settling of cohesive sediment[J]. Advances in Water Science, 2017, 28(2): 285-292. DOI: 10.14042/j.cnki.32.1309.2017.02.014

Effect of flow and electrolyte on the flocculation-settling of cohesive sediment

  • To explore the effect of flow and water salinity on the flocculation-settling of cohesive sediment in estuary and coastal region, we took sediment concentration and floc diameter as parameters, and used a self-made rotary cylinder and electrolyte added method to examine the flocculation-settling process under six flow intensities (0 s-1, 1.38 s-1, 2.54 s-1, 4.67 s-1, 7.19 s-1, 13.2 s-1, 20.3 s-1) and three electrolytes (NaCl, CaCl2, AlCl3). The results showed that: ① The effect of flow on flocculation-settling of cohesive sediment is related to flow intensity. Low intensity flow improves the flocculation-settling at early stage and hinders it at the other stages, while high intensity flow always retards it because of the strong shear stress and turbulent mixing. ② The existence of electrolyte has a net expansionary effect on the action of low intensity flow and a contractile effect for high intensity flow. In the same concentration, when the cation valence of electrolyte becomes from +1 to +3, the influence of flow becomes greater, especially at stabilization period.
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