A simple laboratory experiment of the hindered settling process of high-concentration sediment suspension

Abstract In this study, a simple laboratory settling experiment is performed to examine the hindered settling process of high-concentration sediment suspension. In the suspension, the height of the clear water–turbid water interface undergoes an initial, rapidly decreasing phase followed by a slowly decreasing phase with increasing settling time. The influences of initial settling height, primary sediment concentration and the size distribution of the sediment sample on the hindered settling process of the suspension are investigated. A large initial settling height of the suspension leads to a slow settling velocity of the suspension during the rapidly decreasing phase. The larger the primary particle concentration of the suspension, the more gently the vertical position of the interface decreases during the rapidly decreasing phase. Increasing the primary particle concentration also causes the slowly decreasing phase to appear later. Finally, a fine-grained sediment suspension results in a gentle decrease in the vertical position of the clear water–turbid water interface and a small settling velocity of the interface during the rapidly decreasing phase.