College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China.
Environ Sci Pollut Res Int. 2018 May;25(14):14226-14243. doi: 10.1007/s11356-018-1668-0. Epub 2018 Mar 10.
It remains unclear how the primary particle concentration and salinity conditions influence the flocculation and settling characteristics of water-sediment suspensions. In this study, two sets of experiments were performed to examine the flocculation and settling properties of low- and high-concentration sediment suspensions. In low-concentration suspensions, the sediment concentration undergoes a rapid initial decrease followed by a slow decrease until it approaches zero with increasing flocculation time. Increases in salinity or the valence of cations from the saline solution added to the suspension lead to a more rapidly decreasing sediment concentration with flocculation time. The valence of cations from the saline solution has a larger influence on the flocculation-settling behaviours of the suspension than the salinity. In high-concentration sediment suspensions, the height of the clear water-turbid water interface in the water-sediment suspension experiences an initial, rapidly decreasing phase followed by a slowly decreasing phase with increasing flocculation time. Increasing the primary particle concentration, salinity or valence of cations from the saline solution added to the suspension causes the height reduction of the clear water-turbid water interface to become gentler. Finally, the valence of cations from the saline solution has a greater influence on the settling characteristics of the high-concentration water-sediment suspension than the salinity.
目前尚不清楚初级颗粒浓度和盐度条件如何影响水-泥沙悬浮液的絮凝和沉降特性。本研究进行了两组实验，以研究低浓度和高浓度泥沙悬浮液的絮凝和沉降特性。在低浓度悬浮液中，随着絮凝时间的增加，泥沙浓度会迅速初始下降，然后缓慢下降，直到接近零。盐度或添加到悬浮液中的盐溶液中阳离子的价数的增加会导致泥沙浓度随絮凝时间更快地下降。盐溶液中阳离子的价数对悬浮液的絮凝-沉降行为的影响大于盐度。在高浓度泥沙悬浮液中，水-泥沙悬浮液中清水-浊水界面的高度在絮凝时间增加时经历一个初始的快速下降阶段，然后是一个缓慢下降阶段。增加初级颗粒浓度、盐度或添加到悬浮液中的盐溶液中阳离子的价数会使清水-浊水界面的高度降低变得更加平缓。最后，盐溶液中阳离子的价数对高浓度水-泥沙悬浮液的沉降特性的影响大于盐度。
