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Membrane Bioreactors:Membrane Bioreactors:
State of the Art andState of the Art andTechnology ExchangeTechnology Exchange
R. Shane Trussell, Ph.D., P.E.R. Shane Trussell, Ph.D., P.E.
Seminar for DOW Chemical
Midland, MI
June 21, 2007
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OutlineOutline
IntroductionIntroduction
Membrane IssuesMembrane Issues
Other IssuesOther Issues
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OutlineOutline IntroductionIntroduction
Brief historyBrief history
Configurations andConfigurations and
manufacturersmanufacturersMBR vs. ConventionalMBR vs. Conventional
Membrane IssuesMembrane Issues
Other IssuesOther Issues
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IntroductionIntroduction
An MBR is not aAn MBR is not a
membrane processmembrane process
An MBR is aAn MBR is a
biologicalbiologicalprocess thatprocess that
uses membranesuses membranes
for solidfor solid--liquidliquidseparationseparation
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IntroductionIntroductionMBRMBRss RootsRoots
Dorr Oliver (1960s)Dorr Oliver (1960s)
SuccessfullySuccessfully
coupled activatedcoupled activatedsludge (AS) tosludge (AS) tomembrane separationmembrane separationby early 1970sby early 1970s(sold 27 units(sold 27 unitsbetween 1974 andbetween 1974 and1982)1982)
EMBR process withEMBR process with
flatsheetflatsheet
UFUF
membranesmembranes
Cost prohibitiveCost prohibitive
Capital and O&MCapital and O&M
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IntroductionIntroduction SMBR configurationSMBR configuration
University of TokyoUniversity of TokyoProfessorsProfessorsAyaAya andand
YamamotoYamamoto 19891989WatWat.. SciSci. Tech.. Tech.
JapanJapan
Kubota developed flatKubota developed flat--
sheet SMBRsheet SMBR
Mitsubishi developedMitsubishi developedhorizontal hollowhorizontal hollowfiber SMBRfiber SMBR
CanadaCanada
ZenonZenon developeddevelopedvertical hollow fibervertical hollow fiber
SMBRSMBR
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IntroductionIntroduction SMBR configurationSMBR configuration
Breakthrough forBreakthrough forcommercialized MBRcommercialized MBRtechnologytechnology
Reduced energy by 90%Reduced energy by 90%
JapanJapan
Kubota dominates withKubota dominates with
6060MBRsMBRsby 1996 (totalby 1996 (total1.5 MGD)1.5 MGD)
UK, Canada, and USAUK, Canada, and USA
Milton, Ontario, CAMilton, Ontario, CA
19971997Arapahoe, CO, USA 1998Arapahoe, CO, USA 1998
Kingston Seymour, UKKingston Seymour, UK19921992
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IntroductionIntroduction SMBR manufacturers in theSMBR manufacturers in the
USAUSA-- firstsfirsts
ZenonZenonwas 1.0 MGD inwas 1.0 MGD inArapahoe, CO in 1998Arapahoe, CO in 1998
Mitsubishi was 0.10 MGD inMitsubishi was 0.10 MGD inByfieldByfield, MA in 2000, MA in 2000
Kubota was 0.6 MGD in RunningKubota was 0.6 MGD in RunningSprings, CA in 2002Springs, CA in 2002
US Filter was 0.16 MGD inUS Filter was 0.16 MGD in
LakeLake OconoceeOconocee, GAG in 2003, GAG in 2003 Zenon is the predominantMBR manufacturer with themost experience andcapacity
Kubota is the runner-upwith significantknowledge andinstallation capacity
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Submerged MBR (SMBR)Submerged MBR (SMBR)Q
Primary Treated
Wastewater
WASTE
EffluentEffluentEffluentEffluentAeration Basin
Waste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated Sludge
Solids RecycleSolids RecycleSolids RecycleSolids Recycle
QR = 3-5xQ
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External MBR (EMBR)External MBR (EMBR)
Primary TreatedPrimary TreatedPrimary TreatedPrimary Treated
WastewaterWastewaterWastewaterWastewater
Solids RecycleSolids RecycleSolids RecycleSolids Recycle
EffluentEffluentEffluentEffluentAeration BasinAeration BasinAeration BasinAeration Basin
Q
QR = 20-30xQ
Waste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated Sludge
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AirAir--liftlift EMBREMBR
Primary TreatedPrimary TreatedPrimary TreatedPrimary Treated
WastewaterWastewaterWastewaterWastewater
Solids RecycleSolids RecycleSolids RecycleSolids Recycle
EffluentEffluentEffluentEffluent
Aeration BasinAeration BasinAeration BasinAeration Basin
Q
QR = 5-10xQ
Waste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated Sludge
DiffuserDiffuserDiffuserDiffuser
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ZENONZENON Hollow fiberHollow fiber
membranemembrane
configurationconfiguration
ProprietaryProprietary
polymerpolymer
UltrafiltrationUltrafiltration 1998 First MBR1998 First MBR
Installation inInstallation in
the USA wasthe USA was
operational atoperational at
1.0 MGD in1.0 MGD in
Arapahoe, COArapahoe, CO
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ZENONZENON 48 modules combine48 modules combine
to form a cassetteto form a cassette
One common headerOne common header
Permeate drawnPermeate drawn
from top andfrom top and
bottombottom
IntermittentIntermittent
coarse bubblecoarse bubble
aeration (10s on/aeration (10s on/
10s off)10s off)
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ZENONZENON
Membranes submerged at end of aeration basinMembranes submerged at end of aeration basin
System capable of operating withSystem capable of operating with backpulsebackpulse
oror relaxrelax
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Kubota /Kubota / EnviroquipEnviroquip Flat sheet membraneFlat sheet membrane
configurationconfiguration PolyethylenePolyethylene
MicrofiltrationMicrofiltration
2002 First MBR2002 First MBRInstallation in theInstallation in theUSA was operationalUSA was operationalat 0.6 MGD inat 0.6 MGD in
Running Springs, CARunning Springs, CA
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Kubota /Kubota / EnviroquipEnviroquip
100 flat sheets100 flat sheets
combine to formcombine to formcassettecassette
Each sheet hasEach sheet hastube connectiontube connectionto headerto header
Constant coarseConstant coarsebubble aerationbubble aeration
to mitigateto mitigatemembrane foulingmembrane fouling
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Kubota /Kubota / EnviroquipEnviroquip
Cassette submerged in aeration basinCassette submerged in aeration basin DoubleDouble deckerdecker (DD) configuration(DD) configuration
System operates with membrane relax, noSystem operates with membrane relax, no
backpulsebackpulse
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US Filter/US Filter/ MemJetMemJet Hollow fiberHollow fiber
membranemembraneconfigurationconfiguration
PVDFPVDF
MicrofiltrationMicrofiltration
2003 First MBR2003 First MBRInstallation in theInstallation in theUSA was operationalUSA was operational
at 0.16 MGD in Lakeat 0.16 MGD in LakeOconee, GAOconee, GA
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US Filter/US Filter/ MemJetMemJet Bundles of 4Bundles of 4
membrane modulesmembrane modules Common header for 4Common header for 4modulesmodules
Combination ofCombination of
air/liquid jetair/liquid jet JetJetTechTech is used tois used to
provide crossprovide cross--flowflowto the membraneto the membranesurfacesurface
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US Filter/US Filter/ MemJetMemJet Separate tankSeparate tank
for membranesfor membranes BackwashingBackwashing
cycle:cycle:
45 s relax45 s relax
15 s permeate15 s permeate
backflushbackflush
15 s coarse15 s coarse
bubble airbubble air
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Mitsubishi / GE IonicsMitsubishi / GE Ionics
Hollow fiber membraneHollow fiber membrane
configurationconfiguration(horizontal)(horizontal)
PolyethylenePolyethylene
MicrofiltrationMicrofiltration
2000 First MBR2000 First MBRInstallation in theInstallation in theUSA was operationalUSA was operational
at 0.10 MGD inat 0.10 MGD inByfieldByfield, MA, MA
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Mitsubishi / GE IonicsMitsubishi / GE Ionics 50 membrane modules50 membrane modules
for 1 membrane bankfor 1 membrane bankModules connect toModules connect to
common headercommon header
Permeate drawn fromPermeate drawn fromboth sides (L and R)both sides (L and R)
Constant coarseConstant coarse
bubble aerationbubble aeration
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Mitsubishi / GE IonicsMitsubishi / GE Ionics
Membranes submerged in aeration basinMembranes submerged in aeration basin
System operates with membrane relax, noSystem operates with membrane relax, no
backpulsebackpulse
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Membrane ComparisonMembrane Comparison
--0.50.50.40.4MitsubishMitsubish
ii
170170--0.40.4KubotaKubota
4004000.20.20.080.08US FilterUS Filter
2902900.10.10.0350.035ZenonZenon
MembraneMembrane
Area/Footprint,Area/Footprint,
ftft22
/ft/ft22
AbsoluteAbsolute
MWCO,MWCO,
mm
NominalNominal
MWCO,MWCO,
mm
ManufacturerManufacturer
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KochKoch PuronPuron
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EMBREMBRss ReRe--BirthBirth--Air PumpsAir Pumps
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How does MBR compareHow does MBR compareto what isto what is commoncommon
wastewater practice?wastewater practice?
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Drivers for ProcessDrivers for Process
SelectionSelection Intended use of treated waterIntended use of treated water
Effluent limitsEffluent limits ScalabilityScalability
Site constraintsSite constraints
Flexibility withFlexibility withexpansions/retrofitsexpansions/retrofits
Capital costCapital cost
O&M costO&M cost
Training/Expertise requirementTraining/Expertise requirement
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TechnologiesTechnologies
Goal is to remove COD, TN, TSS,Goal is to remove COD, TN, TSS,and Pathogensand Pathogens
Small to medium capacity < 5 MGDSmall to medium capacity < 5 MGD
Oxidation DitchOxidation Ditch
Sequencing Batch Reactor (SBR)Sequencing Batch Reactor (SBR)
Membrane Bioreactor (MBR)Membrane Bioreactor (MBR)
Large capacity > 5 MGDLarge capacity > 5 MGD
Conventional activated sludgeConventional activated sludge Pure oxygen activated sludgePure oxygen activated sludge
Membrane Bioreactor (MBR)Membrane Bioreactor (MBR)
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Flow Scheme for ConventionalFlow Scheme for Conventional
Activated Sludge ProcessActivated Sludge Process
Backwash
Water
Secondary
Clarifier
Secondary
Clarifier
WASTE
ToDisinfection
Microfiltration
ConventionalConventional
Aeration BasinAeration Basin
Primary Treated
Wastewater
Fl S h f th MBR dFl S h f th MBR d
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Flow Schemes for the MBR andFlow Schemes for the MBR andConventional Activated SludgeConventional Activated Sludge
ProcessProcess
Primary Treated
Wastewater
Backwash
Water
Secondary
Clarifier
WASTE
ToDisinfection
Microfiltration
Conventional
Aeration Basin
WASTE
MBR
Aeration Basin
To
Disinfection
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Sequencing BatchSequencing BatchReactorsReactors
SBR is a fillSBR is a fill--and draw typeand draw type
activated sludge systemactivated sludge system
Equalization, aeration andEqualization, aeration and
clarification all performed in theclarification all performed in the
same batch reactorsame batch reactor
React Settle Decant
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Retrofitting SBR with MBR
Capacity increases by 8-fold Batch becomes Continuous
MLSS increases from 3 to 10 g/L
DisinfectionPrimary TreatedWastewater
Waste
Activate
Sludge
Membrane TankAeration Tank
Solids RecycleQR = 3-5Q
Q
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Oxidation DitchOxidation Ditch
Oxidation ditch is an activated sludge process
that utilizes long solids retention times
CAS SRT = 5 avg. days
Oxidation ditch SRT = 20 avg. days
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Oxidation DitchOxidation Ditch
Double Ditch
Triple Ditch
Mechanical aerators
More capacity, more ditches
Typical HRT is 24 h
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TechnologiesTechnologiesAll conventional technologies that
compete with MBR use gravity forsolid-liquid separation
Additional filtration process required toAdditional filtration process required toattain recycled water statusattain recycled water status
Membrane filtration required to attain aMembrane filtration required to attain asimilar water qualitysimilar water quality
MBR has great potential to reduceMBR has great potential to reducedisinfection requirementsdisinfection requirements
Commercial MBRs to date are not marketedin in a manner that allows operationsimilar to pure oxygen plants
Low SRT operation to prevent nitrificationLow SRT operation to prevent nitrificationand significantly reduce oxygen requirementsand significantly reduce oxygen requirements
This is because membrane fouling rates areThis is because membrane fouling rates areincreased with low SRT designsincreased with low SRT designs
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TechnologiesTechnologiesObvious winner for MBR
Space limitationsSpace limitations
High quality effluent requiredHigh quality effluent requiredDebate amongst practicing engineers in
USA as to the economics of MBRcompared to membrane filtration of
secondary effluents for largewastewater treatment facilities
Less aeration required on settledLess aeration required on settledeffluent because less solids presenteffluent because less solids present
Higher flux and reduced capital costHigher flux and reduced capital cost
Reality is established cleaningReality is established cleaningintervals are different (2intervals are different (2ndnd effluenteffluentevery 3 to 4 weeks while MBR every 1every 3 to 4 weeks while MBR every 1to 3 months)to 3 months)
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TechnologiesTechnologiesLarge membrane facilities treating secondaryLarge membrane facilities treating secondary
effluenteffluent
Orange County Water District 85 MGDOrange County Water District 85 MGD
West Basin Municipal Water District 40West Basin Municipal Water District 40MGDMGD
Clark County Water Reclamation DistrictClark County Water Reclamation District30 MGD30 MGD
Large MBR facilitiesLarge MBR facilities
Traverse City 17 MGD facilityTraverse City 17 MGD facility
Tempe 10 MGD facilityTempe 10 MGD facility
King CountyKing County BrightwaterBrightwater 38 MGD38 MGD
Irvine Ranch Water District 20 MGDIrvine Ranch Water District 20 MGD
MBRsMBRs economic viability depends on theeconomic viability depends on theentire picture of a given locationentire picture of a given location
Cost of land and availabilityCost of land and availability
Total present worth costsTotal present worth costs
Overall project goalsOverall project goals
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Principle Advantages ofPrinciple Advantages ofMBR ProcessMBR Process
High qualityHigh qualityeffluenteffluent
CompactCompact
FootprintFootprint
High MLSSHigh MLSS
concentrationsconcentrations
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Some obvious benefitsSome obvious benefits
ofofMBRsMBRs areare
MBR produces an excellentMBR produces an excellent
effluent qualityeffluent quality
MBR has a much smallerMBR has a much smaller
footprintfootprint
smaller aeration tankssmaller aeration tanks no clarifiersno clarifiers
no filtersno filters
MBR has great potential forMBR has great potential for
being highly automated andbeing highly automated and
requiring little operatorrequiring little operator
attentionattention
MBR AdvantagesMBR Advantages
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MBR eliminates the needMBR eliminates the need
for monitoring sludgefor monitoring sludge
settleability as ansettleability as anoperational parameteroperational parameter
Effluent quality is notEffluent quality is not
dependent on operationsdependent on operationsNot necessary to determineNot necessary to determine
TSS/VSS concentrations toTSS/VSS concentrations to
maintain desired SRTmaintain desired SRT
Can use fixed waste rateCan use fixed waste rate
SRT=V/QSRT=V/QWASWAS
MBR AdvantagesMBR Advantages
d
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Higher MLSS concentrations (More bugHigher MLSS concentrations (More bugmass per volume)mass per volume)
Membrane provides solidMembrane provides solid--liquidliquidseparationseparation
SBR or Ox. Ditch 2SBR or Ox. Ditch 2
--4 g/L4 g/L
MBR 8MBR 8--12 g/L12 g/L
MBR makes longerMBR makes longerSRTsSRTs feasiblefeasible
Reduced solids handling costsReduced solids handling costsMore stable nitrogen removal processMore stable nitrogen removal process
MBR AdvantagesMBR Advantages
d
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MBR AdvantagesMBR Advantages
Membrane provides an absolute barrierMembrane provides an absolute barrier
and effluent quality is no longer aand effluent quality is no longer a
concern.concern.
ND to 10ND to 101000 to1000 to
10,00010,000
FecalFecal
Coliform,Coliform,
#/100#/100mLmL
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Public Health BenefitPublic Health Benefit
Membrane is anMembrane is anabsolute barrier thatabsolute barrier thatphysically removes allphysically removes allpathogenspathogens
ConventionalConventional
technologies depend ontechnologies depend onhighly selectivehighly selectivechemical orchemical or
photochemical reactionphotochemical reactionPathogens may repairPathogens may repair
themselves and reactivatethemselves and reactivate
Results from operatingResults from operating
MBR plants:MBR plants:
MBR AdvantagesMBR Advantages
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Total ColiformsTotal Coliforms
MitsubishiMitsubishi
ZenonZenon
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation, h
Concentration
,MPN/100mL
Primary Eff luent Total Coliforms MBR Permeate Total Coliforms
open symbols denote below detection limit
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation, h
Concentration,MPN/100mL
Primary Eff luent Total Coliforms MBR Permeate Total Coliforms
open symbols denote below detection limit
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Fecal ColiformsFecal Coliforms
MitsubishiMitsubishi
ZenonZenon
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation. h
Concentration,
MPN/100mL
Primary Eff luent Fecal Coliforms MBR Permeate Fecal Coliforms
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation, h
Concentration,MP
N/100mL
Primary Effluent Fecal Coliforms MBR Permeate Fecal Coliforms
I di C li h
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IndigenousIndigenous ColiphageColiphage
Mitsubishi
ZenonZenon
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation, h
Concentration
,PFU/100mL
Primary Eff luent Total Coliphage MBR Permeate Total Coliphage
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
0 250 500 750 1000 1250 1500 1750 2000 2250 2500
Time of Operation, h
Concentration,PF
U/100mL
Primary Eff luent Total Coliphage MBR Permeate Total Coliphage
Wh MBR?Wh MBR?
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MBR Effluent Allows Modern Objectives to beMBR Effluent Allows Modern Objectives to be
RealizedRealized
Ideal for UV disinfectionIdeal for UV disinfection All particulate matter and suspended solids thatAll particulate matter and suspended solids that
can interfere with UV have been rejected atcan interfere with UV have been rejected at
membrane barriermembrane barrier
High percentHigh percent transmissivitytransmissivity (>70%)(>70%)
Dose of 80 mJ/cmDose of 80 mJ/cm22 adequate for MBR effluent,adequate for MBR effluent,
while 100 mJ/cmwhile 100 mJ/cm22 required for granular filteredrequired for granular filtered
wastewaterwastewater Ideal pretreatment process for reducing TDSIdeal pretreatment process for reducing TDS
Suitable for direct feed to ROSuitable for direct feed to RO
ChloramineChloramine residual is requiredresidual is required
Why MBR?Why MBR?
Aqua 2000 Bureau StudyAqua 2000 Bureau Study
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0
25
50
75
100
125
150
175
200
0 250 500 750 1000 1250 1500 1750 2000
Time of Operation, h
NetOperatingPre
ssure,psi
0
5
10
15
20
25
30
35
40
Temperatur
e,
C
Net Operating Pressure Temperature
Plant shutdow n
Feed TDS = 1200 mg/L
Aqua 2000 Bureau StudyAqua 2000 Bureau Study[[FilmtecFilmtec BW 30BW 30--4040, low pressure TFC RO membranes]4040, low pressure TFC RO membranes]
11 weeks
Principle Disadvantage of MBRPrinciple Disadvantage of MBR
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Principle Disadvantage of MBRPrinciple Disadvantage of MBR
ProcessProcessAbility to maintain hydraulic capacityAbility to maintain hydraulic capacityAll treated wastewater exiting an MBRAll treated wastewater exiting an MBR
process must pass through the membraneprocess must pass through the membrane
Peak flows arePeak flows area particularlya particularly
significantsignificantissueissue
Cold weatherCold weather
can furthercan furthercomplicate thiscomplicate thisissueissue
Peaking StudiesPeaking Studies
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Peaking StudiesPeaking Studies
Peaking studies are commonlyPeaking studies are commonly
performed to estimate the sustainableperformed to estimate the sustainable
flux under wet weather flow scenariosflux under wet weather flow scenarios
These peaking studies are frequentlyThese peaking studies are frequently
performed during dry weatherperformed during dry weather
conditions and not during a stormconditions and not during a stormeventevent
Typically, the flux is increased toTypically, the flux is increased to
mimic storm conditions for a periodmimic storm conditions for a periodof hours or daysof hours or days
Peaking StudiesPeaking Studies
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Peaking StudiesPeaking Studies
Three significant issues to be aware of:Three significant issues to be aware of:
New membranes do not provideNew membranes do not provide
representative performancerepresentative performance
Temperature influence on TMP needs to beTemperature influence on TMP needs to be
accounted foraccounted forFlux @ 20C Overall Vacuum Pressure
SustainableSustainable
membrane fluxmembrane flux
isis greatlygreatly
influencedinfluencedbyby
mixed liquormixed liquorpropertiesproperties
h l iT h l i
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TechnologiesTechnologiesManufacturers and design engineers are
still learning how to address peak
flows
Store peak flow in equalization tanksStore peak flow in equalization tanks Need adequate spaceNeed adequate space
Generally required for peaking factor >Generally required for peaking factor >
2.52.5
Economics will depend on the specificEconomics will depend on the specific
applicationapplication
Purchase additional membrane capacityPurchase additional membrane capacity
Generally more expensive solution forGenerally more expensive solution for
peaks > 2.5peaks > 2.5
Often preferred by the MBR manufacturerOften preferred by the MBR manufacturer
Design decisions need to be made withDesign decisions need to be made with
extra membranes (e.g. operate or store)extra membranes (e.g. operate or store)
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Break/Questions?Break/Questions?