This paper focused on the hydrodynamic research aiming at the short-circuit evaluation for five different outlet configurations through the compartments of a mechanical flocculation unit of vertical shaft with mixing paddles in pilot scale. The tests were carried out with two, three and four compartments, variable and constant velocity gradients, including alternative sense of paddle rotation (clockwise in first compartment, anticlockwise in the following one and so on). The research pointed out that the relevance of outlet configuration increases with the reduction of the number of compartments. In opposite, the velocity gradient and the sense of the paddle rotation seem less significant features. These results open the perspective of viable increasing of performance, with low financial investments, mainly for flocculation units with three or two compartments installed in overloaded water treatment plants.
- hydrodynamic evaluation
- mechanical flocculation
- model of series of stirred tanks
- outlet configuration
- water treatment
- First received 17 March 2015.
- Accepted in revised form 7 July 2015.
- © IWA Publishing 2015