Prof. C. H. Lee, Seoul National University

Water Environment-Membrane Technology Lab.Seoul National University

Let’s open the biological black-box in Membrane BioReactor :

MBR for the next generation

Director & Prof. Chung-Hak LEE,

Institute of Environmental Protection and SafetyWater Environment – Membrane Technology Lab.School of Chemical Engineering,

Seoul National University, KOREA


MBR : Worldwide Buisiness

~ thousands of installations of MBRs in the World

Vivendi (France), Memcore (USA)Zenon (Canada), Mitsubishi, Kuboda (Japan), etc..

~ 750 MBRs in Korea since last 6 years


Commercial MBR plants in Korea *2003(2002)

CROSSFLOWCROSSFLOWFILTRATIONFILTRATION

200(200(--))13(13)13(13)19961996PSFPSF(30,000Da)(30,000Da)--ZENIX ENG.ZENIX ENG.

TUBULAR TUBULAR MEMBRANEMEMBRANE

RUSSIARUSSIA

734(559)734(559)TOTALTOTAL

2,000(2,000)2,000(2,000)50(50)50(50)19951995PESPES(40,000Da)(40,000Da)

BIOSUFBIOSUFAQUATECHAQUATECHMEMBRATEKMEMBRATEK(SOUTH AFRICA)(SOUTH AFRICA)

350(250)350(250)20(2)20(2)20022002CPVCCPVC(0.25 )(0.25 )--PUREPURE

ENVIENVI--TECHTECH

PUREPUREENVIENVI--TECHTECH(KOREA)(KOREA)

4,000(900)4,000(900)68(67)68(67)19991999PolyolefinPolyolefin(0.4)(0.4)NIXNIX--MBRMBR

ZENIX ENG ZENIX ENG & JIN WOO & JIN WOO

ENV.ENV.PLATEPLATE

MEMBRANEMEMBRANE

YUASAYUASA(JAPAN)(JAPAN)

--101020022002PVDFPVDF(0.1(0.1--0.4)0.4)--RAPAHRAPAH

TECHTECH天津膜天社天津膜天社

((CHINA)CHINA)

--10(10)10(10)19981998PSFPSF(0.1)(0.1)

KIMAS KIMAS ⅠⅠ,,ⅡⅡKOLONKOLON

SKC,SKC,E.N.E.E.N.E.

(KOREA)(KOREA)

600(225)600(225)150(100)150(100)20022002PE PE (0.4)(0.4)--KMSKMSKMSKMS

(KOREA)(KOREA)

1,000(300)1,000(300)10(7)10(7)20002000PVDFPVDF(0.035)(0.035)

ZENOGEMZENOGEMSAESAE--HANHANZENONZENON(CANADA)(CANADA)

DEADDEAD--ENDENDFILTRATIONFILTRATION

4,000(1,400)4,000(1,400)403(300)403(300)19971997PEPE(0.4)(0.4)

SMAS & SMAS & HANTHANT

KEC &KEC &HECHEC

HOLLOWHOLLOWFIBERFIBER

MEMBRANEMEMBRANE

MRCMRC(JAPAN)(JAPAN)

FitrationFitrationModeMode

Highest Highest capacitycapacity

(M(M33/d)/d)Number of Number of InstallationInstallation

Starting Starting YearYear

MembraneMembraneMaterialMaterial

(PORE SIZE, (PORE SIZE, ㎛㎛ ))

Trade Trade markmarkCompanyCompanyModule typeModule typeMembraneMembrane

ManufacturerManufacturer


Biofouling

: Membranes in contact with the broth of activated sludge reactor will be colonized within short time by microorganisms, leading to the formation of a composite layer known as biofilm.

: Biofouling has restricted the widespread application of MBR,because i) it limits the maximum flux obtainable,

ii) it leads to substantial cleaning requirements, iii) it shortens membrane life time


Overview of factors leading to membrane biofouling

Environmental & Operating Factors

• Substrates• DO• Air flow rate &

bubble size• pH• Temperature• Growth mode

(attached or suspended)

• Growth phase (log or endogenous)

• Cyclic format in SBR

• etc

MicroorganismsEPSOrganic debrisInorganic particlesIons

Size

Shape

Density

Porosity

Stickiness

Membrane

Biofouling

( )

Biofilm composition and structure

Biofilmproperties( )

Bulk phase composition ( )

cR

fR

J

?

?

?

?


Biofilm in resistance in series model

η⋅++∆

=)( cfm RRR

PJ

Rm : Intrinsic Membrane Resistance

Rf : Fouling layer resistance (specific membrane-solute interactions, either by surface deposition or pore fouling) Bulk phase Compositions

Rc : Cake layer resistance Biofilm (e.g., floc properties)

.


Overview of factors leading to membrane biofouling


• Substrates• DO• Air flow rate &

bubble size• pH• Temperature• Growth mode

(attached or suspended)

• Growth phase (log or endogenous)

• Cyclic format in SBR

• etc

MicroorganismsEPSOrganic debrisInorganic particlesIons

Size

Shape

Density

Porosity

Stickiness

Membrane

Biofouling

( )

Biofilm composition and structure

Biofilmproperties( )

Bulk phase composition ( )

cR

fR

J

?

?

?

?


Highlights of the past on MBR

Raw Wastewater

Treated water

MF/UF(<0.2um)

Bioreactor

Black box ?Flux !!!(Engineering, Materials)


TMP profile of (a) MSBR with anoxic phase of 10 min. and (b) MSBR without anoxic phase.

0

5

10

15

20

25

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

Time (day)

TMP

(kPa

)

(a) (b)

anoxic fill aerobic filtration0 10min 3hrs 50min

10min 10min 2hrs 50min 50min

Cycle format

(a)(b)


Membrane Fouling

?

Membrane Fouling

PhysicochemicalApproach

HydrodynamicApproach

MicrobiologicalApproach

Flow regime: (side stream vs. submerged )Module type:(tubular, plate,hollow fiber)Critical flux

Membrane materialsMembrane surface modificationHybrid systemChemical additivesSurface chemistry


Membrane Fouling

Membrane Fouling

PhysicochemicalApproach

HydrodynamicApproach

MicrobiologicalApproach

Flow regime: (side stream vs. submerged )Module type:(tubular, plate,holow fiber)Critical flux

Biofilm formation mechanism(Quorum sensing, etc.)

Cell physiology& morphologyMicroorganism population dynamics

Membrane materialsMembrane surface modificationHybrid systemChemical additivesSurface chemistry


Let`s Open the Black box in MBR

Morphology of activated sludge

Hybrid system (Biological activated carbon )Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Effect of Floc Morphology on Membrane Fouling

• Pin point floc (left)• Bulking sludge (right)• Normal activated sludge (center)


Effect of Floc Morphology on Membrane Fouling

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5Concentration Factor

J/Ji

w(%

)

Normal Sludge

Pin point Sludge

Bulking Sludge

Fig. 3b Flux declines according to floc structures during ultrafiltration of activated sludge with PM30 membrane


Analysis of resistances in MBR

∆Pt; Pressure dropµ ; Fluid viscosityε ; PorosityL ; Cake layer thicknessψ ; sphericityk ; Kozeny constantdp ; Particle diameter

=mR f(Membrane Material, Pore size, etc.)

=cR f(Deposited microbial flocs, biofilm)

3

22

)1(6εε

ψ−

⋅

=

pdLk)( fcm

t

RRRPJ++

∆=µ

=fR f(Membrane Meterial, EPS, SMP, etc.)


N- limited Activated sludge

0

20

40

60

80

100

120

1 2 3 4 5

Conce ntration Factor

Nitroge n-limite d Activate d S ludge

Contro l Activate d S ludge

YM30 Membranes


EPS contents under different nutrient condition

SludgeType

Rm(1011×m-1)

Rc(1011×m-1)

Rf(1011×m-1)

Rt(1011×m-1)

Rc/Rt(%)

EPS(VS mg/g MLSS)

ControlN-limitation

1918

9757

12

11777

8374

245151


Effect of SRT on Membrane Flux

0

20

40

60

80

100

120

1 2 3 4 5 6

Co nc e ntra tio n Fa c to r

S R T = 33 d a yS R T = 8 d a yS R T = 3 d a y

XM30 Membranes


EPS content of activated sludge flocs at different SRT

SRT EPS content

Range(VS mg/g MLSS)

Average(VS mg/g MLSS)

3 days 234∼276 268

8 days 228∼273 244

33 days 187∼242 213




Hybrid system (Biological activated carbon )

Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Addition of PAC in MBR

Operation time (day)0 4 8 12 16 20 24

Suc

tion

pres

sure

( -c

mH

g)

0

5

10

15

20

25

30

Activated SludgeBAC Sludge

• Filtration PE 0.1 µm, 0.056 m2

Flux 15 L/m2/hrair flow : 2.0 L/min

• Bioreactor MLSS: 6,000~10,000HRT 4~6 hour SRT 25~40 dayLoading

2.2~2.4 (kgCOD/m3/day)

0.3 bar




Hybrid system (Biological activated carbon )

Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Effect of Physiological states of Activated Sludge on Membrane Biofouling


EPS contents of activated sludge flocs at different growth phase

Rm(1011×m-1)

Rc(1011×m-1)

Rf(1011×m-1)

Rt(1011×m-1)

Rc/Rt(%)

EPS(VS mg/g MLSS)

YM30Log growth phaseEndogenous phase

1820

3363

0.10.1

5183

6576

200270

PM30Log growth phaseEndogenous phase

43

4282

1311

5996

7185

200270


Effect of Foaming on Membrane Biofouling

01020304050

60708090

100

1 2 3 4 5

Co nc e ntra tio n Fa c to r

No n-Fo a mingFo a ming 1Fo a ming 2

YM30 Membranes


Hydrophobicity of foaming and non-foaming activated sludge

Characteristic ofactivated sludge

Relative Hydrophobicity(%)

Range Average

non-foamingfoaming 1foaming 2

54 ∼ 6065 ∼ 9362 ∼ 91

578082




Hybrid system (Biological activated carbon )Cell physiology (Growth phase)

Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


TMP profiles at various DO concentrations under constant pneumatic mixing intensity

AirN2 gas

DO0.3mg/L

7.0mg/L

0

5

10

15

20

25

30

35

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (hr)

TM

P (k

Pa)

DO7.0mg/L

DO1.7mg/L

DO0.3mg/L

0.5hr 1.5hrs1.1hrs0

5

10

15

20

25

30

35

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (hr)

TM

P (k

Pa)

DO7.0mg/L

DO1.7mg/L

DO0.3mg/L

0

5

10

15

20

25

30

35

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time (hr)

TM

P (k

Pa)

DO7.0mg/L

DO1.7mg/L

DO0.3mg/L

0.5hr 1.5hrs1.1hrs




Hybrid system (Biological activated carbon )Cell physiology (Growth phase)Cell physiology (DO concentration)

Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Effect of Cycle Format on Membrane Fouling in Membrane-coupled Sequencing Batch Reactor(SBR)

0

5

10

15

20

25

0.0 5.0 10.0 15.0 20.0 25.0

Time (day)

TMP

(kPa

)

6.8day 21.5dayMSBR(A/O/-) MSBR(-/O/-)


Image analysis(-/O/-) (A/O/-)

x200x200MSBR(A/O/-); MSBR with anoxic phaseMSBR(-/O/-); MSBR without anoxic phase


EPS analysis in Membrane –coupled SBR

( ) : standard deviation

5.0( 0.2)

2.4( 0.2)

52.7( 1.8)

24.1( 1.4)

MSBR - ) (mg/L)

2.2( 0.2)

1.0( 0.1)

66.5( 1.9)

35.8( 1.7)

MSBR(- /O/ - ) (mg/L)

PolysaccharideProteinPolysaccharideProtein

EPS (soluble)EPS (bound)

5.0( 0.2)

2.40.2)

52.71.8)

24.1( 1.4)

MSBR(A/O/ - ) (mg/L)

2.20.2)

1.00.1)

66.5( 1.9)

35.8( 1.7)

MSBR(- /O/ - ) (mg/L)

PolysaccharideProteinPolysaccharideProtein

± ± ±

± ± ±

±

±(A/O/


Stickiness of Biofilm vs. cycle formatin SBR

Cake Disc

Single blade paddle mixer

05

1015202530354045

0 100 200 300 400 500

Time (min)

Turb

idity

(NTU

)

MSBR(A/O/-)

MSBR(A/O/F)

MSBR(-/O/-)

MSBR(A/O/-); MSBR with anoxic phaseMSBR(-/O/-); MSBR without anoxic phase


MSBR (O)MSBR (A/O)

S- A- A-S-

S- : Suspended

A- : Attached

Phylum. Proteobacteria phy.Class. BetaProteobacteria

Order. BurkholderialesFamily. Comamonadaceae

Genus. Diaphorobacter

Khan,S.T.,et al . Appl. Environ. Microbiol. 68 (7), 3206-3214 (2002) :

Comamonadaceae, are primary PHBV-degrading denitrifiersin activated sludge.


Distribution of microorganismsbetween bulk phage and membrane

S1 S2 S3 S4 S5 S6 S7 S8 M5M1 M2 M3 M435％

60％

0 7 13 29 34 47 58 68 7 13 29 47 68

DGGE profile ( Yamamoto et al.,2004)

340047S6,M4

246034S5

220029S4,M3

204013S3,M2

364068S8,M5

386058S7

MLSS (mg/l)

Operation time(day)

Lane

21707S2,M1

17200S1

Membrane and sludge have different DGGE band patternsMicrobe on membrane surface was selectively grown




Hybrid system (Biological activated carbon )Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)

Cell physiology (Pump Shear)Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Effect of pumping device on flux in crossflow MBR

Operation time (hour)

0 24 48 72 96 120 144

Flux

(L/m

2 /hr)

0

50

100

150

200

centrifugal pump

rotary pump


Resistance Analysis

• Resistance-in-series model

J PR

PR R Rt m c f

=⋅

=⋅ + +

∆ ∆µ µ ( )

Pump typeResistance(1012m-1) Rotary Centrifugal

0.6317.917.9

0.6219.119.1

0. 6010.810.8

0.4411.811.8

Rm

Rc

Rf

Rt

* Resistance after 7 days’ crossflow operation


Particle Diameter(µm)

1 10 100 1000

Vol

ume

Freq

uenc

e(%

)

0

10

20

without recirculation recirculation with centrifugal pump - 7dayrecirculation with rotary pump - 7day


0.30.20.4~0.5Observed sludge

yield(gMLVSS/gCOD)

MBR with a centrifugal

pump

MBR with arotary pump

Conventionalactivated sludgePump type

Sludge Production in MBR system :Observed sludge yields in conventional activated sludge and in crossflow MBR




Hybrid system (Biological activated carbon )Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)

Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Membrane- coupled Fixed bed bioreactor

Pressure gauge

Water bath

Membrane module

Tap water

Support media (option)

Suction pump

Level sensor

Feeding pump

Electronic balance

Permeate Personal computer

Air diffuserConcentrated synthetic

wastewater


Suspended vs.Attached

Attached Growth Reactor(MLSS: 100~2,000 mg/L, attached

biomass: 2,000 mg/L)

Suspended Growth Reactor(MLSS: 2,000~5,000 mg/L)


Comparison of Filtration Performance :Suspended vs.Attached

0

5

10

15

20

25

30

35

0 50 100 150

Operation time (hr)

Tra

nsm

em

bra

ne p

ress

ure

(kPa)

Attached growthMLSS: 100 mg/L, attached biomass: 2,000 mg/L

Suspended growthMLSS: 3,000 mg/L


Filtration behaviors with varying MLSS concentration in attached and suspended growth MBR

Attached growth(mgMLSS/L)

Suspended growth(mgMLSS/L)

All attached growth reactors contain additional 2,000 mg/L of attached biomass.

0

5

10

15

20

25

30

35

0 50 100 150 200 250

Operation time (hr)

Tra

nsm

em

bra

ne p

ress

ure

(kP

a)

1001,000

1,5002,000

3,0002,000

5,000


Specific Resistances of Mixed Liquors

n = 0.79

n = 1.08

n = 1.04

n = 1.07

1.0E+11

1.0E+12

1.0E+13

1.0E+14

1 10 100 1000

Pressure (kPa)

Specific

cak

e resist

ance

(m/k

g)

Attached growthMLSS: 100 mg/L,attached biomass: 2,000 mg/L


Attached growthMLSS: 2,000 mg/L,attached biomass: 2,000 mg/L


•The mixed liquor of attached growth would have a higher fouling potential compared with that of suspended growth.

•At the same MLSS of 2,000 mg/L, mixed liquor from both attached and suspended growth revealed similar cake properties. similar filtration behavior at the same MLSS concentration


Formation of Dynamic Membrane

Low molecular weight or submicron colloidal particle

Microbial floc

Attached growth(without suspended solids)

Suspended growth

Membrane DYNAMIC MEMBRANE




Hybrid system (Biological activated carbon )Cell physiology (Growth phase)Cell physiology (DO concentration)Cell physiology (Cycle Format in SBR)Cell physiology (Pump Shear)

Growth mode (Suspended vs. Attached)Conclusion and Research on MBR in 21C


Conclusion


in MBR

Biofilm

Properties ( )

Bulk phase properties ( )

cR

fR

?

? ?

Membrane

Biofouling

( )J?

?

Membrane Biofouling is determined by the matrices of biofilm and bulk phase which are governed by environmental and operating factors.

The matrices of biofilm and bulk phase are in dynamic equilibrium with communities and physiology of microorganisns which are continuously changing.


Past research on MBR ?

Environmental &Operating Parameters

•Growth mode(attached or suspended)•Growth phase(log or endogenous)•Dissolved oxygen •SRT•Pumping shear•Air flow rate & bubble size•MLSS Conc.•Cyclic format inSBR

, etc.

.

.

MembraneFiltration

Performance

Higher Flux

Longer life time

Easy Cleaning

Lower EnergyConsumption

MicrobialProperties

(Biofouling)

BlackBox

•Microbial Floc Size•Specific Resistance& Compressibility•EPS type & conc.

•Morphology•Adhesion Strength

BlackBox


TMP profile of (a) MSBR with anoxic phase of 10 min. and (b) MSBR without anoxic phase.

0

5

10

15

20

25

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

Time (day)

TMP

(kPa

)

(a) (b)

anoxic fill aerobic filtration0 10min 3hrs 50min

10min 10min 2hrs 50min 50min

Cycle format

(a)(b)


Research on MBR in 21C

Using the tool of molecular biology ( FISH, PCR-DGGE, Quorum Sensing )

Biofilm formation mechanism

Cell Morphology & Physiology

Microorganism population dynamics

Innovative MBR processInnovative MBR process


Need for Molecular Biology to improve MBR

Molecular Biology provides high-level information

which is not attainable by traditional methods:

- Track critical groups of microorganisms

- Track specific metabolic reaction


Biofilm formation mechanism:Quorum Sensing

Autoinducer, low molecular weight, diffusible signaling molecules, can be involvedin the induction of various genes that are responsible for aggregation behavior, EPS-production, disaggregation, and so on.


Biofilm formation mechanism:Quorum Sensing

Cell-Cell communication :

Thus, cell-to-cell communication may be of fundamental importance to the dynamics of aggregation in flocs and biofilmsand needs more attention in the future.

The issue is how to identify and control autoinducers involved in biofilm formation in MBR consisting of heterogeneous mixture of microorganisms instead of pure culture.


Thank you for your attention !!

Prof. C. H. Lee, Seoul National University

Documents

Transcript of Prof. C. H. Lee, Seoul National University