Effects of super-powdered activated carbon pretreatment on coagulation and trans-membrane pressure buildup during microfiltration.
As a pretreatment for membrane microfiltration (MF), the use of powdered activated carbon (PAC) with a particle size much smaller than that of conventional PAC (super-powdered PAC, or S-PAC) has been proposed to enhance the removal of dissolved substances. In this paper, another advantage of S-PAC as a pretreatment for MF is described: the use of S-PAC attenuates trans-membrane pressure increases during the filtration operation. The floc particles that formed during coagulation preceded by S-PAC pretreatment were larger and more porous than the floc particles formed during coagulation preceded by PAC pretreatment and those formed during coagulation without pretreatment. This result was due to increased particle-particle collision frequency and better removal of natural organic matter, which inhibits coagulation by consuming coagulant, before the coagulation reaction. The caked fouling layer that built up on the membrane surface was thus more permeable with S-PAC than with normal PAC. Both physically reversible and irreversible membrane foulings were reduced, and more stable filtration was accomplished with S-PAC pretreatment.
Matsui
Yoshihiko
Y
Graduate School of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan. matsui@eng.hokudai.ac.jp
Hasegawa
Hiroki
H
Ohno
Koich
K
Matsushita
Taku
T
Mima
Satoru
S
Kawase
Yuji
Y
Aizawa
Takako
T
D002606:Charcoal / Q000737:chemistry*; D005427:Flocculation; D014462:Ultrafiltration / Q000295:instrumentation / Q000379:methods*; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000032:analysis / Q000737:chemistry
D014873:Water Pollutants; D002606:Charcoal