Thesis - faculty.ait.ac.th - Asian Institute of Technology

Where:
Rt = Rm + Rn + Rc Eq. 3.2
Rm = intrinsic resistance (1/m)
Rn = resistance due to irreversible fouling (1/m)
Rc = resistance due to cake layer (1/m)
The membrane after clogging was taken out of the reactor for cleaning. The
membrane was first cleaned with tap water to remove the cake layer attaching on the
membrane surface follows by chemical cleaning as listed in Table 3.4 until the membrane
resistance was recovered to the initial membrane resistance.
Table 3.4 Description of the Chemical Cleaning
Stage Cleaning Agent Concentration Running Time (min)
1 NaOH 3% by weight 20
2 Ultra pure water 10
3 HNO3 1% by weight 20
4 Ultra pure water 10
3.6.2 Experimental Set-up
The experiments were conducted in two reactors namely: (1) yeast membrane
bioreactor (YMBR), and (2) bacterial membrane bioreactor (BMBR) as shown in Figure
3.5. The reactor and the membrane dimensions of the bacterial and yeast bioreactor were
similar. The experimental set-up consists of a feed tank placed above the bioreactors. The
volume of the feed entering the bioreactor from the feed tank was maintained by a level
controller tank. A volume of 5L was maintained in the bioreactor. The technical details of
the membrane bioreactor are given in Table 3.5.
Table 3.5 Technical Parameters of the Experimental Plant
Parameters Description
Manufacture Mitsubishi Rayon
Model STNM424
Membrane surface (m 2 ) 0.42
Type of module Hollow fibre
Membrane material Polyethylene
Nominal pore size (µm) 0.1
Reactor shape Cylindrical
Reactor material Transparent acrylic
Reactor diameter (cm) 10
Reactor volume (L) 5
Aeration Stone diffuser
Backwashing Air backwash
Cleaning 3% NaOH and 1% HNO3
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