DESCRIPTION
Sedimentation is a process used widely in the clarification of water and wastewater. Particles settle from suspension in different ways, depending on the concentration of the suspension and the characteristics of the particles. The simplest type of sedimentation is the settling of a dilute suspension of particles which have little or no tendency to flocculate. In these circumstances, the prediction of clarification rates and their scale-up to plant design is relatively straightforward. For higher concentrations where inter-particle effects become significant and where agglomeration may take place, different regimes of settling rate occur, known as ‘zone’ settling (fig 1). Information from batch tests for such systems forms a vital part of the search for the optimum design and operation of industrial sedimentation tanks.
The Sedimentation Studies Apparatus allows demonstration of these different characteristics for any chosen sediment/water system.
Five equal sized glass cylinders are mounted vertically on a backboard incorporating measuring scales. Each of the cylinders may be removed from the board for washing, filling and mixing of the solid particles. Solutions containing different amounts of suspension can be placed in the cylinders and the differences in sedimentation rate observed by measuring the changes in height of the various solid/liquid interfaces with respect to time (e.g. fig 2).
The equipment includes the following accessories necessary for a self-contained facility: stop clock, three plastic beakers of 2 litre capacity, specific gravity bottle. An accurate balance (not supplied) is required for weighing the solids. The whole apparatus is bench-mounted and provided with back lighting.
UTILITIES REQUIRED
- Electronic Top Pan Balance
Capacity: 3000g Sensitivity: 0.1g
- Electrical supply: 220-240V/1ph/50Hz
