Coarse bubble aeration, extensively used in submerged as well
as in certain side-stream MBR configurations, has been proven to
significantly enhance the performance of the membrane filtration
process and has been applied extensively since the early days of
MBR technology [18]; however, the exact effects of air scouring are
still not fully understood [19]. Lately, significant interest has been
placed on studying and modeling the complicated flow field
prevailing in the vicinity of the membrane surfaces, including
the fluctuating local shear stresses and the complicated interactions
between air bubbles and induced shear forces that facilitate
detachment of material from, and control of, the biofouling layer
[17,19–21]. In such studies, detailed knowledge of the rheological
properties of the activated sludge liquor is considered of primary
importance [22].