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BiofilmReactors:
OPERATIONALOVERVIEWANDAPPLICATIONSFORNUTRIENT
REMOVAL
WWOA46th
AnnualConference
October11,2012
LeonDowning,Ph.D.,P.E.
Donohue&Associates
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Acknowledgements
WaterEnvironmentFederation(WEF)Manualof Practice(MOP)No.29
OperationofNutrientRemovalFacilities
LeadAuthor:LeonDowning
AssistantAuthors:
FrankKulick,BrentwoodIndustries
MikeDempsey,Ph.D.,ManchesterMetropolitanUniversity
SarahHubbell,EntexTechnologies
JoshBoltz,Ph.D.,P.E.,BCEE,CH2MHill
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Outline
Whatisabiofilm?
Whyisthisimportant?
Biofilmreactorcontrols
Currentapplications
Futuredirection
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Whatisabiofilm?
cellsimmobilizedatasubstratumandfrequently
embeddedinanorganicpolymermatrix[EPS]of microbialorigin
CharacklisandMarshall1990
Whybiofilmandnotfixedfilm???
Biofilmisscientificallyacceptedterm
Betterdescribeswhatthefilmis(i.e.biologicalfilm)
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Whatisabiofilm?
Cellresidencetimeindependentofhydraulicresidence
time
Increasedvolumetricactivity
Increasedoperationalstability
Increasedresistancetotoxic/inhibitoryshockloads
Differentbioconversionprocessesinthesamereactor
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Whyisthisimportant?
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Whyisthisimportant?
Whatmakesabiofilmdifferent?
Notallcellsseethesamething
Masstransferconstraints
Whatcontrolsabiofilm?
Rateoftransferintothebiofilm
Thicknessofbiofilm
Activityinthebiofilm
S
NH4+
BulkLiquid Biofilm
NO3
DO
BOD
S
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Whyisthisimportant?
BiofilmResearch
Confirmedstratificationofbiofilm
Heterotrophsoutside
AOBandNOBinside
MeasuredDO,ammonium,nitrite,
andnitrateinabiofilm
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BiofilmOperation
Howdoesstuffgetintoabiofilm?
LIQUIDTRANSFER
LAYER BIOFILMATTACHMENT
SURFACE
Aerobic
Anoxic/Anaerobic
CBOD5
NH4+
NO3
D.O.
DetroitAirportFountain(ConcourseA)
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BiofilmOperation
Controllingnitrification
Getsstuffintothebiofilmfaster
Decreasesmooth
flowlayerthickness
Increaseliquiddissolvedoxygen
concentration
Preventexcessbiofilmthicknessand
sloughing
Consistent,gentlescouringofbiofilm
Nottoothick,nottoothin,butjust
right
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BiofilmOperation
Whatareourknobs
toturn?
Liquidvelocity
Aeration(MBBR,IFAS)
Mechanicalmixing(MBBR)
Backwashing(BAF)
Flushingwater(TricklingFilter)
Rotationspeed(RBC)
IncreaseDOconcentration
Increaseswithliquidvelocityincrease
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BiofilmOperation
Solidssettleability
Smallparticlesize=poorbioflocculation
Options:
Downstreamflocculation(biologicalorchemical)
Downstreamfiltration
OdegaardetalWEF/IWABiofilmReactorTechnologies2010
ManitowocWWTP
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Technologies
Oldestapplicationsin
wastewatertreatment
Tricklingfilter(1890s)
Attachmenttowalls
observedtoincrease removalinactivatedsludge
(1960s)
Aerobicprocesses
Lowtech,easytooperate
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TechnologiesA.TRICKLINGFILTER
INFLUENT
EFFLUENT
B.MOVINGBEDBIOFILM
REACTOR(MBBR)
AIR AIR AIR
INFLUENT
EFFLUENT
C.INTEGRATEDFIXEDFILM
ACTIVATEDSLUDGE(IFAS)
AIR AIR AIR
INFLUENT
EFFLUENTSOLIDS
RECYCLE
EFFLUENTINFLUENT
D.ROTATINGBIOLOGICAL
CONTACTOR(RBC)
E.BIOLOGICALLYACTIVEFILTER
(BAF)
DOWNFLOW
DOWNFLOW AIR
AIR AIR AIR
INFLUENT
EFFLUENTSOLIDS
RECYCLE
FloatingMedia
FixedMedia
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Technologies
TricklingFilter
A.TRICKLINGFILTERINFLUENT
EFFLUENT
Biofilmsupport
Rocks
Crossflowmedia
MainControls
Recirculationflowrate
Increaserecirculationflowincreases
liquidvelocityand
oxygen
concentration
Forcedventilation
Oxygensupply
Temperaturecontrol
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KeyComponents
Splkraft(SK)Value
Measureoftheintensity
ofwaterapplication
Moreintenseapplication higherSKvalue
thinnerfilmandfewerflies
Moreintenseflow lessfrequentapplication
Wettingefficiency
Frequencyofwaterapplication
Toofrequent odorissues
Notfrequentenough flyissues
Providesufficientrecoverytimeforbiofilmwithout
dryingout
Howcantheseparametersbe controlled?
Numberofarms
Rotationalspeed
Recirculationpumpingrate
Lowintensitywater
application(splashing)
Highintensitywater
application(dousing)
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Splkraft(SK)Value
SKvalue
SK=THL/(Na
*d
)
THL=TotalHydraulicLoad(influentplusrecirculation)
Na
=Numberofarms
d
=Rotationalspeed
IncreasedSKMoreIntenseApplication Healthierbiofilm
LowerSK LessHealthyBiofilm HigherSK HealthierBiofilm
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NumberofArms
TwoArms
Increasedapplicationintensity
Requiresfasterrotationspeed
Moretimebetween
application
FourArms
Decreasedapplicationintensity
Requiresslowerrotationspeed
Lesstimebetweenapplication
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Example
Tricklingfilteroperation
Qin
=3.3MGD
Qr
/Qin
=3
Rotationalspeed=4min/rev.
2ARMS 4ARMS
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WhereareweOperating?
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KeytoSuccesswithTricklingFilters
FindtheRightBalance
Processandhydraulicperformance
Loadingrates
Recirculationrate
Biofilmthicknessandhealth
Rotationalspeed
Recirculationrate
Numberofdistributorarms
Odorandflycontrol
Rotationalspeed
Numberofdistributorarms
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Technologies
MBBRB.MOVINGBEDBIOFILM
REACTOR(MBBR)
AIR AIR AIR
INFLUENT
EFFLUENT
MovingBedBiofilmReactor
Floatingmediainreactor
NO
suspendedgrowthrecycle
Compactprocess
Multistageprocess
L:Wcloseto1:1
Laterstages:lowconcentrations
Selectforbugs
thatthriveunderasetof
conditions
Maincontrols
Aerationsupplyrate
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Technologies
MBBR
Mediaretentioniskey
RetentionSieves
Effluentcylinders
Drains
Overflows
Everywhere
Influentscreeningiscritical
Withprimaryclarifiers:6mm
Withoutprimaryclarifiers:3mm
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Technologies
MBBR
Whatcanwecontrol?
Biomassconcentration
Biofilmthickness:selfregulating
Mediavolume:typicallysetduring
design
Notalotofcontrol
DOconcentration
Mediumbubbleaeration
OperateathigherDO46mg/L)
LIQUIDTRANSFE
RLAYER BIOFILMATTACHMENT
SURFACE
AerobicAnoxic/Anaerobi
CBOD5
NH4+
NO3
D.O.
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Technologies
IFAS
IFAS
Firstapplication
1943
Gainedmomentuminlate1990s
Maindriver:increasednitrificationin
sametankvolumeAIR AIR AIR
INFLUENT
EFFLUENTSOLIDS
RECYCLE
FloatingMedia
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Technologies
IFAS
Floatingmedia
SamecontrolasMBBRforthebiofilm
SamecontrolasASforsuspendedgrowth
Fixedmedia
Clumping
risk
Onebigmassofbiomass
Nodiffusiontocenter
Periodicspargingiskey
Finebubbleaeration
Coarsebubblescouring
Whatcanwecontrol?
Aerationsupplyrate!
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BiofilmandFutureNutrientLimits
Whatrolecanbiofilmsplay?
LowerPlimitleadstolargerchemicaldemand
Maximizebiologicalphosphorusremoval
Moreexistingbasinavailableforselectorvolume
Incorporateselectorvolumeforbiopanddenitrification
Nonewtankage
AIR AIR AIR
INFLUENT
EFFLUENTSOLIDS
RECYCLE
FloatingMedia
AIR AIR
INFLUENT
EFFLUENTSOLIDS
RECYCLE
FloatingMedia
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BiofilmandFutureNutrientLimits
Whatrolecanbiofilmsplay?
Clarifierlimitation
IncreasebiomasswithoutincreasingMLSS
Higherbiologicalactivity,samesolidsloadingtoclarifier
Wetweather
Highpeakflowscanwashout
suspendedgrowth
Biofilmsarestuck
Highpeakfacilitiesmaybenefitfrombiofilmprocess
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Questions?
LeonDowning,Ph.D.,PEDonohue&Associates
(920)[email protected]
Biofilm Reactors: OPERATIONAL OVERVIEW AND APPLICATIONS FOR
NUTRIENT REMOVALAcknowledgementsOutlineWhat is a biofilm?What is a
biofilm?Why is this important?Why is this important?Why is this
important?Biofilm OperationBiofilm OperationBiofilm
OperationBiofilm OperationTechnologiesTechnologiesTechnologies
Trickling FilterKey ComponentsSplkraft (SK) Value Number of
ArmsExampleWhere are we Operating?Key to Success with Trickling
FiltersTechnologies - MBBRTechnologies - MBBRTechnologies -
MBBRTechnologies - IFASTechnologies - IFASBiofilm and Future
Nutrient LimitsBiofilm and Future Nutrient LimitsQuestions?
