Abstract
In order to explore the influence of floc characteristics on membrane fouling, flocs after breakage and re-growth were compared with those formed by conventional coagulation process when alum was used as coagulant. The results showed that, though the average size of flocs after breakage and re-growth was smaller than that without breakage, the fractal dimension of flocs after breakage and re-growth was lower than that without breakage independent of the dosage of alum. The increase of trans-membrane pressure (TMP) was lower when the flocs formed in breakage and re-growth process. When the dosage of alum increased, the fractal dimension (D2) of flocs without breakage decreased a little while D2 of flocs with breakage and re-growth was nearly the same. Moreover, lower dosage of alum (0.1mM) caused higher increase of TMP with conventional coagulation process, comparing with higher dosage of alum (0.3mM); while it was nearly the same when the flocs formed with breakage and re-growth process. The fractal dimension is an important factor influencing the increase of TMP compared with the average size of flocs, and a lower frequency of small flocs may cause a smaller increase of TMP. The characteristics of flocs surface changed after breakage and re-growth and this may also affect the increase of TMP.
Original language | English |
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Pages (from-to) | 194-199 |
Number of pages | 6 |
Journal | Journal of Membrane Science |
Volume | 385-386 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Dec 2011 |
Externally published | Yes |
Keywords
- Floc surface
- Flocculation index
- Flocs breakage
- Fractal dimension
- Membrane fouling