Backflushing, pulsation and inline flocculation techniques for flux improvement in crossflow microfiltration

Abstract

Crossflow microfiltration (CFMF) is a better technique for removal of particles from water suspension. Clogging is the main drawback of membrane application, which causes a drop in permeate flux. Numerous techniques are available for flux improvement. In this work, three such techniques backflushing, pulsation and in-line flocculation, are reviewed. Two experimental studies have been analyzed and compared. In both techniques, better flux was reported with cleaning frequency of 1min. This shows that a longer interval causes increased internal clogging and deposition. However for the backflushing case, longer duration of backflushing produced higher flux improvement, while pulsating performed inconsistently with stop duration. Net permeate volume was observed higher in both experiments when Tf= 1min, Tb=1 sec and Tf=1 min, Ts=1 sec. This is due to higher flux at Tf=1min and longer net operation time. Comparing the flux improvement in both techniques without flocculent addition, backflushing produced 200% increment at Tf=1 min and Tb=5 sec. This was 63% at Tf=1min and Ts=1 sec with pulsating. Flux increment was 162% with backflushing at Tf=1 min and Tb=1 sec.