ABSTRACT
Sedimentation takes place in settling or sedimentation tanks or basins, where water rises vertically for discharge through effluent channels in specific flow patterns suited to tank size and shape. In rectangular tanks, water flow will be rectilinear; center-fed and square settling tanks will operate with radial flow, and peripheral-feed basins use spiral flow. Design criteria include overflow rate, weir loading and detention time (1 to 10 hours is typical), and horizontal velocity for rectangular tanks. Equipment choice is determined using empirical data from full-size tank use performance. No matter what the equipment size and shape, settling tanks are designed for slow and steady water movement.
