Pulse bubble sparging for fouling control

• Power transferred was delineated to quantify the effect of different sparging scenarios on fouling.
• Power transfer efficiency is significantly greater for pulse bubble sparging than for coarse bubble sparging.
• Lower fouling rates were observed in the zone of influence of the bubbles.
• Spacing between spargers could be optimized knowing the width of zone of influence.

The extent of fouling control in air sparged submerged membrane systems is dependent on the hydrodynamic conditions generated by sparging and the resulting shear stress induced onto membranes. Although the optimal sparging conditions (i.e. bubble size and frequency) that promote fouling control remain unclear, recent studies suggest that pulse bubble sparging is more efficient for fouling control than coarse bubble sparging. The present study demonstrated that pulse bubble sparging was substantially more effective at transferring power to the membranes than coarse bubble sparging. Pulse bubble sparging required approximately 50% less power for fouling control than coarse bubble sparging. The spatial distribution of fouling was not homogenous in the system; lower fouling rates were observed in the zone of influence of bubbles. The width of the zone of influence induced by gas sparging increased with bubble size and frequency, indicating that the size and frequency of bubbles can be optimized to minimize the required number of spargers in a system and therefore the total volume of gas required for fouling control.