Fully-grown flocs in a mixing tank of membrane filtration with dead-end membranes are ruptured
while passing through a pump and the ruptured flocs are aggregated again in a membrane-feed-pipe
(MFP). To look at more details, this study relates the reaggregation to a parameter of mixing
intensity in the MFP, i.e., G-value. The G-value is a function of Reynolds number, pipe diameter,
friction factor and average velocity in the MPF. To deal with the polydispersity condition, the authors developed a
representative particle size called Effective Diameter for Polydisperse
condition in Dead-end filtration (EDPD). The experimental results show that as the G-value increases, the
EDPD decreases, and also the cake resistance increases. An in-line injection system, which injects
coagulant just before a pump and has no mixing tank, is also tested for comparison. Results
suggest that as the G-value goes above 3,100sec-1, the floc sizes at an inlet to the membrane
increase in the case of in-line injection compared to the one with a mixing tank. The cake resistance
decreases. Given that most treatment plants operate with the G-value larger than 3,100sec-1, this
suggests that there is a strong possibility of replacing the mixing tank for coagulation and flocculation
with an in-line injection system. Includes 16 references, figures, tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1000 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 35 |
| Published : | 06/01/2007 |
