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 Safety Water Environment – Membrane Technology Lab. School of Chemical Engineering, Seoul National University, KOREA
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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
Water Environment-Membrane Technology Lab.Seoul National University
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Overview of factors leading to membrane biofouling
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Effect of Floc Morphology on Membrane Fouling
• Pin point floc (left)• Bulking sludge (right)• Normal activated sludge (center)
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Effect of Physiological states of Activated Sludge on Membrane Biofouling
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Hydrophobicity of foaming and non-foaming activated sludge
Characteristic ofactivated sludge
Relative Hydrophobicity(%)
Range Average
non-foamingfoaming 1foaming 2
54 ∼ 6065 ∼ 9362 ∼ 91
578082
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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/-)
Water Environment-Membrane Technology Lab.Seoul National University
Image analysis(-/O/-) (A/O/-)
x200x200MSBR(A/O/-); MSBR with anoxic phaseMSBR(-/O/-); MSBR without anoxic phase
Water Environment-Membrane Technology Lab.Seoul National University
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/
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Comamonadaceae, are primary PHBV-degrading denitrifiersin activated sludge.
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
•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
Water Environment-Membrane Technology Lab.Seoul National University
Formation of Dynamic Membrane
Low molecular weight or submicron colloidal particle
Microbial floc
Attached growth(without suspended solids)
Suspended growth
Membrane DYNAMIC MEMBRANE
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
Conclusion
Environmental & Operating Factors
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.
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
TMP profile of (a) MSBR with anoxic phase of 10 min. and (b) MSBR without anoxic phase.
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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
Water Environment-Membrane Technology Lab.Seoul National University
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.
Water Environment-Membrane Technology Lab.Seoul National University
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.
Water Environment-Membrane Technology Lab.Seoul National University