Chemistry Reference
In-Depth Information
Sand
Filter
Sand
Filter
Sand
Filter
Activated
Sludge
Activated
Sludge
Activated
Sludge
Pre-treatment
Pretreatment
Pretreatment
Disinfection
Disinfection
Disinfection
Clarifier
Clarifier
Clarifier
Clarifier
Clarifier
Clarifier
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
Sludge
Digestion
Sludge
Digestion
Sludge
Digestion
CONVENTIONAL WASTE
WATER TREATMENT
MEMBRANE
FILTRATION
MEMBRANE
FILTRATION
MEMBRANE
FILTRATION
Activated
Sludge
Activated
Sludge
Activated
Sludge
Pre-treatment
Pretreatment
Pretreatment
Clarifier
Clarifier
Clarifier
Clarifier
Clarifier
Clarifier
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
Sludge
Digestion
Sludge
Digestion
Sludge
Digestion
CONVENTIONAL WASTE
WATER TREATMENT
INCLUDING MEMBRANE FILTRATION
Activated
Sludge
Activated
Sludge
Activated
Sludge
Pretreatment
Pretreatment
MBR
MBR
MBR
Pre-treatment
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
Sludge
Dewatering/
Disposal
MEMBRANE BIOREACTOR
MEMBRANE BIOREACTOR
Figure 8.4 Schematic representation of the steps required in waste water treatment by various
technologies. MBR, membrane bioreactor. Adapted fromMazzei et al
#
2009, with permission
from Elsevier.
aerobically, anaerobic membrane bioreactors may be a good alternative. Operational
costs are lower because of the low anaerobic growth yields - there is less sludge to be
disposed of [33] - and because bio gas is produced. Instead of aeration, fouling control
can be achieved by sparging the bio gas produced [34]. However, since insufficient bio gas
is produced, it must be recycled and compressed, so only slightly less energy than in
aerobic membrane bioreactors is required [35]. A more intensive form of biodegradation
can be achieved by integrating anaerobic and aerobic zones within a single bioreactor.
There are four types of integrated anaerobic-aerobic bioreactor: (1) integrated membrane
bioreactors with physical separation of anaerobic and aerobic zones; (2) integrated
membrane bioreactors without physical separation of anaerobic and aerobic zones; (3)
sequencing batch reactors (SBRs) based on temporal separation of the anaerobic and the
aerobic phases; and (4) combined anaerobic-aerobic culture systems based on the
principle of limited oxygen diffusion in microbial biofilms. Few examples of integrated
aerobic-anaerobic membrane bioreactors without physical separation of anaerobic and
aerobic zones are reported [36,37].
Several combinations of membrane bioreactors and waste water technologies (hybrid
membrane bioreactors) other than the conventional activated sludge process have been
proposed. The use of a hybrid membrane bioreactor is an excellent alternative for the
treatment of industrial waste waters, especially when space is limited or real estate costs are
high. In the biofilm membrane bioreactor (BF-MBR), biofilms grow on fluidized supports
through the use of high N-removal by simultaneous biofilm denitrification [38-42]. In
addition, less biomass is suspended and the circulating media generate some scrubbing
action, which improves filterability despite the fact that the attached biomass has a much
higher fouling potential than suspended activated sludge. Integrated operation between
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