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7/21/2019 MBR-C1 Fundamentals of MBR
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MBR CourseFundamental of MBR Processes &Introduction to Process Design Tools
October 16 & 17, 2012
Hamid Rabie
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Function of a WWTP
Removal of particulate materials
sand hairs, fibrous materials
other solids
Biodegradation of undesired components
Solid liquid separation
WWTPEffluent
Surplus sludge (biomass)
Wastewater
phosphorus biomass
carbon
nitrogen
sulphur
CO2 + biomassN2 + biomass
biomass
Microbial rejection
biomass rejection
standard sedimentation: 10,000 CFU/ml(colony forming unit: cfu)
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Solid - Liquid
Separation
Biological Process
Fundamentals of Bio-Reactor Processes
Wastewater Effluent
SludgeEngineered systems to:
Accumulate microorganisms for oxidation of electron donor pollutants.
Convert soluble pollutants to large particles (biomass) for separation.
Settling Filter media Membrane
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Fundamentals of Bio-Reactor Processes
Aerobic
Anoxic Aerobic
Anaerobic Anoxic Aerobic
Pollutant Measurement Biological Reaction Process Name Condition
Carbonaceous BOD, COD cellsCOOrganic O
+ 22 BOD Removal Aerobic
Ammonia N - NH3 cellsNONH O + 332 Nitrification Aerobic
Nitrate TNcellsNNO
+
23
Denitrification Anoxic
Phosphorous TP cellsP Bio-P Removal Anaerobic
BOD / Nit
BOD / Nit / Denit
BOD / Nit / Denit
Bio-P
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First Use of Membranes in Biological WWT
SGFPCBS
= Step screen= Grid and fat removal= Primary clarifier= Biological step
STDCMT
= Sedimentation tank= Third cleaning step (e.g. filtration)= Membrane technology
Effluent treatment with membrane technology tertiary treatment
Raw
wastewater
Effluent
S GF PC ST DCBS MT Permeate
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Membranes at the End of WWT Process
Always end of the processes
Tertiary treatment
Almost similar to surface water treatment (need for coagulant)
Low solid concentrationtolerance in membrane stage
Mostly dead end filtration mode
Sensitive against foulingcomponents
Interesting for existing WWTP that need disinfection or reuse
additional costs to conventional technology;additional footprint required
no hair and fibrous material allowedrequires easy sludge management
Pressurized membrane systems or
Submerged membrane systems
fouling components come in direct contactwith membrane surfaces;often additional flocculation required;operation difficult to optimize
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Raw
wastewater
S
Effluent
TCPC BS STGF
Changes in the MBR System
S
GFFSBS
= Step screen
= Grid and fat removal= Fine screen= Biological step
MT = Membrane technology
Membrane bioreactor (MBR)
BSFS MT
Permeate
Combination ofbiological stepand solid liquidseparation
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MBR vs. Conventional Activated Sludge
Pre-TreatmentIncomingWastewater Effluent
AnoxicZone
AerobicZone
SettlingTank
RAS
Conventional Activated Sludge SystemConventional Activated Sludge System
Pre-TreatmentIncomingWastewater
AnoxicZone
AerobicZone
RAS
Membrane Bioreactor (MBR)Membrane Bioreactor (MBR)
EffluentMF/UF
In case of TertiaryMore processes;
e.g. sand filter
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MBR Reduces the Footprint
Membranes
Eliminate all clarifiers
Replace withmembrane systems
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Major Differentiations of MBR Technology
Activated
SludgeProcess
Membrane
FiltrationMBR
Stable
Biological
Treatment
Process
Absolute
SolidsSeparation
Replaces conventional clarification; requires less footprint
Combines physical barrier of a membrane with biological treatment
Produces high quality effluent at all times Comparable to tertiary treatment; then LCC is conventional technologies
membranekey component to this market
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Better effluent quality> 95%, 98% and 99.9% for COD,BOD, SS removal
Effluent TSS independent of
bioreactor efficiency
High MW organics are retained andbio-degraded
Improved biological reactions (dueto longer SRT, shear, etc.)
Process ControlComplete separation between HRTand SRT
Accurate control over sludge age,development of slow-growing
microorganisms (nitrifiers)
Increased EfficiencyAll bacteria retained, cold weathernitrification
Insoluble P retained reducing
chemical addition for P removal
High MLSS (1-2%), greater organicloads and less sludge production
Compact systems, less footprint
Sludge digestion within bioreactor
Modular expansion
Absorbs variation and fluctuations inincoming flow and organic loads
Advantages of MBR over Conventional
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Market Areas for MBR Technology
MembraneBioreactors
leachate
municipalwastewater textile
industry
industriallaundries
pulp &paper
tank
cleaning
beverageindustry
dairyindustry
vegetableindustry
fruitindustry
Slaughter-house /
rendering
petrochemindustry
chemicalindustry
pharmacy
industry
High ammoniacontent
High CODcontent
High CODcontent
High & variablesalt content
Space limitation
reuse; high quality
High &variable salt
content
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Increasing regulatory standards
especially regarding disinfectant by-
products and waterborne pathogens
Limited supply
tap into alternative supplies
such as water re-use
Growing demand
due to population growth, newinfrastructure in developed
countries, and aging infrastructure
in industrialized countries
Technological innovation
development of low cost,
high quality water treatment
solutions
Growth inMembrane
Technology
Drivers of MBR Market & Technology
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Hollow fiber modules Plate modules
GE-Zenon
Mitsubishi
Siemens-Memcor
Koch Membrane-Puron
Micronet PF
Kubota
Toray
Huber
A3 Gmbh
Tubular modules
Outside/In FiltrationImmersed (Vacuum)
Outside/In FiltrationImmersed (Vacuum)
Inside/Out Filtration(Pressurized Vessel)
Main Configurations for MBR Technology
X-Flow / Pentair
Berghof
Koch Membrane
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modules cross flow operation
MBR with Tubular Modules -Cross Flow Membrane Filtration
External cross flow MBR
RCRL
MFDN N
RCRL
MFNDN
recirculationreturn line
membrane filterNitrificationDe-nitrification
PressurePump
Module Length
Pressure
Feed side
Permeate side
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Cross Flow Membrane Filtration for MBR Tubular Membrane (Inside/Out Filtration)
Membrane
Support Material
Feed
(Clean Water)
Permeate
Concentrated
Waste
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Cross Flow Membrane Filtration for MBR Tubular Membrane
Original work-horse in MBR applications; used horizontal configuration
Large diameter membrane tube and high recirculation flow rate and high
TMP served to eliminate potential for plugging with biomass Membrane designed to operate at MLVSS levels > 50,000 mg/l
Energy intensive on large flow rates (> 300,000 gpd)
Low packing density (requires large footprint for large flow rates) New tubular systems from X-Flow uses air plugs in vertical tubes
operating at lower pressures
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Tubular MBR Configurations
MLSS: 12-50 g/L
Flux: 50-150 lmh
High energy consumption:
(1.5-4.0 kWh/m3)
Continuous
TMP: 1.0-5.0 bar
MLSS: 8.0-12 g/L
Flux: 30-50 lmh
Lower energy consumption:
(0.3-1.0 kWh/m3)
Discontinuous
TMP: 0.2-0.6 bar
More valves & complexity
X-Flow Airlift
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Waste water
Air
MBR with Submerged (Immersed) membranes
Biological sludge
Vacuum Pump
Permeate
submergedmembranes
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Basic of Immersed MBR Train
1.Biological reactor
2.Membranes
3.Permeate pump & blower
4. Control panel
5. Permeate & air piping
1
2
43
5
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Immersed Membrane Filtration (hollow fiber)
Membrane
Coarse Bubble
Diffuser
Permeate to Top Header
(Puron has no top header)Support Material
(e.g. Zenon, MPF, Puron)
Permeate to Bottom Header(Siemens has no bottom header)
Bulk Fluid
(Concentrate)
Aeration
Bubbles (forfluid agitation)
Coarse Bubble
Diffuser
Outside/In Filtration
S
uction
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Immersed Hollow Fibers in Operation
Module Installationwith crane
Submerged module in operationair injection phase
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Immersed Membrane Filtration (flat sheet)
Air bubbles between
membrane panelsAir diffusers
Suction
To suction
Panel
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MBR with submerged modules -different tank configurations
Internal submerged MBR
RC
MFDN N
RCRL
MFNDN
recirculationreturn line
membrane filterNitrificationdnitrification
External submerged MBR (Preferred)
RCRL
DN N MF
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Key Aspects of MBR Products
Membrane structure and characteristics
For superior technological and economical performance, should consider:
Module design and features
Membrane tank hydraulics
Membrane filtration process and system design
Aeration system & sludge management
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Classification of membrane processes
Nano-filtration
RO
1
10
100
Pressuredifference
in
[bar]
VirusesBacteria
Saline solutions
0,1
Particle size in [m]
0,1 1,0 10,00,010,0010,0001 100
Sandfiltration
Microfiltration
Ultrafiltration
Membrane pore size range from
different suppliers for MBR
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Comparison of microorganisms vsmembrane pore size
poresize ~ 0,01 m
ultrafiltration
poresize ~ 0,2 m
microfiltration
E. Coli ~ 0,5 - 1,5 m
MS2-Virus (Coliphage)
~ 0,025 m
B. Subtilis~ 0,3 m
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MBR provides better effluent quality
Parameter MBRconvent.
plant
Solids mg/l 0 10 15
COD mg/l < 30 40 50
Ptotal withprecipitation
mg/l < 0,3 0,8 1,0
MLSS content inaeration tank
g/l < 20 < 5
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Key Requirements for Membrane Properties
hydrophilicity - good wetability with water
low fouling tendency
chemical and thermal stability
Material requirements
mechanical stability
narrow pore distribution
minimized number of defects
high porosity
low hydraulic resistance
high bonding of membrane to support material
Morphological requirements
cost-effective materials
cost-effective production
Economic requirements
Diff t T f M b & St t
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Different Types of Membranes & Structures(SEM of Membrane Surfaces)
Mitsubishi
2 m2 m
KubotaToray
3 m2 m
Zenon
Avg. Pore: 0.03 m
PVDF low MW
Asymmetric
Coated on a support
Avg. Pore: 0.1 m
PVDF high MW
Asymmetric
Coated on fabric
Avg. Pore: 0.4 m
Chlorinated PE
Symmetric
Coated on fabric
Avg. Pore: 0.2 m
PVDF low MW
Asymmetric
Double coating
Coated on support10 m
Asymmetric Structure
Membrane Skin/Surface
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Introduction to DesignTools
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Key Elements of MBR Process Design
Full step by step biological reaction analysis and mass balances such as:
Carbon, Phosphorous, Nitrogen, etc
Sludge production
Aeration and nutrient requirements
Step by step process mass balances and all necessary sizing such as:
Pumping and coarse screen
Sand and fat removal Fine screen
Equalization
All dosing systems
Different biological steps
Sludge treatment
Membrane systems: filtration tank, configuration, RAS, sludge g=feed,aeration capacity, blower sizes, pump sizes, chemical dosing, etc
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System Configuration
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Step by Step Process Calculations
S b S P C l l i
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Step by Step Process Calculations
Process Trends for Different Key Parameters
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Process Trends for Different Key Parameters