BF-MBR Process
- 1. Overview
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Coupling bio-film reactors with membrane filtration as bio-film membrane bioreactors (BF-MBR) is an interesting
alternative technology to activated sludge membrane bioreactors (AS-MBR). Bio-film technology for wastewater
treatment can provide a substantially lower suspended solids environment for membrane filtration compared to activated
sludge processes. Potential benefits are; less membrane clogging/sludging problems, lower fouling potentials,
ease of membrane cleaning, reduced energy consumption for air-scouring, and new membrane module and reactor designs.
There has been an idea that the aeration tank with suspended culture can be replaced with bio-film reactor
from the beginning of MBR technology. In this idea, suspended or fixed biocarriers (or media)
are added to aeration tank to grow biofilm on the surface of biocarriers . Strainers are required to prevent
suspended biocarriers from being carried over to membrane tank and damage membrane. The biocarriers commonly
used in moving bed bio-film reactor (MBBR) or integrated fixed film activated sludge (IFAS) can be used for BF-MBR.
Following benefits are typically claimed against conventional MBR with suspended culture,
but the second and the third claims below are not fully supported by data.
· Improved membrane performance due to the lower MLSS (a great portion of microorganisms are attached, not suspended).
· Improved oxygen transfer efficiency (OTE) due to the lower MLSS.
Increased contact time of bubbles with liquid since biocarriers hinder bubbles from rising.
· Due to the increased effective microorganisms population in aeration tank
including suspended and fixed microorganisms, volumetric organic, F/V ratio, can increase while tank size shrinks.
- 2. Processes
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2-1. AO-BF-MBR Process
2-2. MLE-BF-MBR Process
2-3. A2O-BF-MBR Process
2-4. CH2-BF-MBR (Mofified A2O) Process
