This study investigates the impact of air sparging and the system
configuration on the permeate flux in a submerged hollow fiber membrane system. The
study was aimed at establishing the magnitude of the contribution from single phase
cross-flow, dual phase cross-flow (air sparged), and air slug induced physical contact
between the membrane fibers on the resulting permeate flux. The bench scale submerged membrane system used in the study consisted of a constant vacuum system (site vacuum line, vacuum regulator,
two vacuum equilibration chambers), a permeate collection and measurement system
(digital scale and data logger), a submerged membrane system (membrane tank, baffle
and membrane module), and an air sparging system (air line, air flow controller,
peripheral and central aerators). All experiments were performed at a constant transmembrane
pressure and the permeate flux was monitored overt time. The results indicate that single phase bulk cross-flow does not significantly contribute to
maintaining a high permeate flux in a submerged hollow fiber membrane system. On the
other hand, the interactions between sparged air bubbles and the membrane fibers
significantly contribute to maintaining a high permeate flux. The physical contact
between the membrane fibers also significantly contributes to maintaining a high
permeate flux.
The reduction in the permeate flux over time could be characterized by an initial short
period of fast permeate flux decline, followed by a longer period of slower permeate flux
decline for all experimental conditions investigated. The hydrodynamic conditions and
the system configuration had a significant impact on the pseudo-steady state permeate
flux. The pseudo steady state permeate flux that could be maintained in an air-sparged
system was 20 to 60% higher that which could be maintained without air sparging. By
promoting the physical contact between membrane fibers, it was possible to further
increase the pseudo steady state permeate flux by 10 to 20%. The pseudo steady state
permeate flux increased with the extent of air sparging. However, a plateau was observed
above which an incremental increase in air sparging intensity was not accompanied by an
increase in the pseudo steady state permeate flux. The physical contact between the
membrane fibers enhances the permeate flux by eroding the foulant layer that forms on a
membrane surface. Includes 6 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 11 |
| Published : | 11/15/2004 |
