Optimization Study of Flocculation Mixing by Means of Grids
Publication: Journal of Environmental Engineering
Volume 126, Issue 2
Abstract
The purpose of this study was to optimize flocculation mixing created by single grids. Double and triple biplane grids were vertically oscillated within a standard 2 L jar. The turbulent velocities were measured using a 2D laser doppler anemometer. The particle removal performance was observed based on the settled water turbidity. When a larger number of grids were applied, the same average volume velocity gradient (G) could be achieved at lower vertical grid speeds. A uniform and more gentle mixing was therefore created, producing high particle contacts and low particle breakup. The minimum settled water turbidity was also achieved at lower G values. A larger number of grids, especially of high solidity ratio, produced a wider range of G values with low settled water turbidity. These findings showed that the grid mixing performance could be optimized by applying a larger number of high solidity ratio grids. It was also found that grids, at their best arrangement, had a better performance than a standard flat blade impeller.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 126 • Issue 2 • February 2000
Pages: 138 - 144
History
Received: Jul 1, 1998
Published online: Feb 1, 2000
Published in print: Feb 2000
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