TY - JOUR
T1 - An improved flux-step method to determine the critical flux and the critical flux for irreversibility in a membrane bioreactor
AU - van der Marel, P.
AU - Zwijnenburg, A.
AU - Kemperman, Antonius J.B.
AU - Wessling, Matthias
AU - Temmink, Hardy
AU - van der Meer, Walterus Gijsbertus Joseph
PY - 2009
Y1 - 2009
N2 - An improved flux-step method is presented incorporating cleaning steps by relaxation to determine the critical flux and the critical flux for irreversibility. Experiments are performed with activated sludge fed with real municipal wastewater. The improved flux-step method is compared with a common flux-step method often used in the literature. The critical flux for a polyvinylidenefluoride flat-sheet membrane with a pore size of 0.1 μm is 56 ± 2 L m−2 h−1 according to the common flux-step method and 52 ± 3 L m−2 h−1 according to the improved flux-step method. The marginal difference is explained by the application of larger flux-steps in the improved flux-step method. By applying intermediate relaxation the fouling appears to be almost completely reversible, indicating that cake layer formation is the dominant fouling mechanism. The cake layer remains removable up to a flux of 100 L m−2 h−1. The critical flux for irreversibility is therefore larger than 100 L m−2 h−1.
The influence of fouling history is reduced by intermediate relaxation. As a result, the total fouling rate is much lower with the improved flux-step method compared to the common flux-step method, showing almost no fouling rate hysteresis in the improved method.
A low amount of irreversible fouling is measured due to the adsorption of macromolecules, pore blocking, and/or gel formation. Applying the improved method ten times consecutively shows the influence of irreversible fouling on the long term. The critical flux decreases by 4 L m−2 h−1 as a consequence of irreversible fouling during the ten runs representing a long filtration run of 150 h at a net flux of 19 L m−2 h−1.
AB - An improved flux-step method is presented incorporating cleaning steps by relaxation to determine the critical flux and the critical flux for irreversibility. Experiments are performed with activated sludge fed with real municipal wastewater. The improved flux-step method is compared with a common flux-step method often used in the literature. The critical flux for a polyvinylidenefluoride flat-sheet membrane with a pore size of 0.1 μm is 56 ± 2 L m−2 h−1 according to the common flux-step method and 52 ± 3 L m−2 h−1 according to the improved flux-step method. The marginal difference is explained by the application of larger flux-steps in the improved flux-step method. By applying intermediate relaxation the fouling appears to be almost completely reversible, indicating that cake layer formation is the dominant fouling mechanism. The cake layer remains removable up to a flux of 100 L m−2 h−1. The critical flux for irreversibility is therefore larger than 100 L m−2 h−1.
The influence of fouling history is reduced by intermediate relaxation. As a result, the total fouling rate is much lower with the improved flux-step method compared to the common flux-step method, showing almost no fouling rate hysteresis in the improved method.
A low amount of irreversible fouling is measured due to the adsorption of macromolecules, pore blocking, and/or gel formation. Applying the improved method ten times consecutively shows the influence of irreversible fouling on the long term. The critical flux decreases by 4 L m−2 h−1 as a consequence of irreversible fouling during the ten runs representing a long filtration run of 150 h at a net flux of 19 L m−2 h−1.
KW - IR-71531
KW - METIS-256371
U2 - 10.1016/j.memsci.2009.01.046
DO - 10.1016/j.memsci.2009.01.046
M3 - Article
SN - 0376-7388
VL - 332
SP - 24
EP - 29
JO - Journal of membrane science
JF - Journal of membrane science
IS - 1-2
ER -