The MBR Book: Principles and Applications of Membrane

Fundamentals 91
Table 2.13 Sub-critical long-term parameters, from Pollice et al. (2005)
Flux (LMH) dTMP/dt (kPa/h) t crit (hours) Reference
17 0.005 �600 (Wen et al., 2004)
22 0.011 1200 (Wen et al., 2004)
25 0.024 300 (Wen et al., 2004)
30 0.072 250 (Wen et al., 2004)
n.a. 0.023 350 (Frederickson and
Cicek, 2004)
20 – 600 (Lee and Choi, 2004)
8 – 350 (Li et al., 2005c)
30 0.036 360 (Cho and Fane, 2002)
10 0.036 550 (Ognier et al., 2002b)
8 0.03 72 (Brookes et al., 2003a)
7 0.006 96 (Le-Clech et al., 2003b)
9 0.004 240 (Le-Clech et al., 2003b)
18 0.104 48 (Le-Clech et al., 2003b)
12 0.0002 300 (Rosenberger et al., 2002)
Biological floc Feed
EPS SMP Colloids Particulates
Biomaterial residue Passive adsorption Initial pore blocking
Cake formation
Biofilm growth Further pore blocking
Irregular fouling distribution
Redistribution of productivity
Local flux � Critical flux
Severe TMP increase
Stage 1
Conditioning fouling
Stage 2
Steady fouling
Stage 3
TMP jump
Figure 2.33 Fouling mechanisms for MBR operated at constant flux (adapted from Zhang et al., 2006)
described rapid irreversible fouling in this initial stage, and passive adsorption of colloids
and organics have been observed even for zero-flux operation and prior to particle
deposition (Zhang et al., 2006). Another detailed study based on passive adsorption
revealed the hydraulic resistance due to this process to be almost independent of
tangential shear, and the initial adsorption to account for 20–2000% of the clean
membrane resistance depending on the membrane pore size (Ognier et al., 2002b).