PhD Disertation 19 Jan 09 - Asian Institute of Technologyfaculty.ait.ac.th/visu/public/uploads/Data/AIT-Thesis/Doctoral... · B.X. Thanh 14-Jan-09 1/40 B.X. Thanh - 104173 Final Presentation

B.X. Thanh

1/40 B.X. Thanh - 10417314-Jan-09

Fin

al P

rese

nta

tion

Fouling Behavior & Nitrogen Removal in The Aerobic Granulation

Membrane Bioreactor

Bui Xuan Thanh

Prof. C. Visvanathan (Chairman)

Asian Institute of TechnologySchool of Environment, Resources & Development

Environmental Engineering & Management

Dr. Esa Viljakainen

Dr. Oleg V. Shipin

Examination Committee:

SBAR

MBR

Dr. Mathieu Spérandio

2/40 B.X. Thanh - 10417314-Jan-09

Answers For Examiner’s Comments

1. Author should give more precision for such a choice of OLR and NLR values. After

the reduction of NLR (but no information to justify this new choice)

- OLR of 2 kgCOD/m3.d is commonly highest designed for the CAS process in reality.

- NLR of 1 kg N/m3.d was the high loading to investigate the maximum SND of BG-MBR

without external C addition.

- NLR, then reduced to 0.5-0.6 N/m3.d to avoid effect of the pH fluctuation.

2. The time of aeration appears sufficient to remove C & ammonia but nitrates never

appeared in opposite with the appearance of nitrites. Discussion about these

phenomena according to size, granule structure and operation time.

- Nitrite-oxidizing bacteria is inhibited (high toxic nitrite) inhibit nitrate formation.

- Microorganisms (heterotrophs, ammonia-oxidizing, nitrite-oxidizing) exist in 200 µm

from surface. Nitrite-oxidizing bacteria is a minor population (Tsunenda et al., 2003).

(a, b) Yellow: ammonia oxidizing bacteria. Red: other bacteria(c) Yellow: nitrite-oxidizing bacteria. Red: other bacteria

3/40 B.X. Thanh - 10417314-Jan-09

Answers For Examiner’s Comments

3. Biomass concentration in SBAR reached 18 gVSS/L (it could be interesting to

differentiate active biomass from volatile biomass compounds

- This method measured volatile biomass (VSS) based on the TOC of mixed sludge

conversion factor (Tijhuis et al., 1994).

- VSS = active biomass + cell debris (biomass decay)

- In CAS, active biomass = 85-90% VSS.

- In granular sludge, it is probably lower (long retention of granule) further study.

4. Discuss the configuration in relation with performances and cost, could such a

system be relevant only with an immersion of membranes in a specific zone of setter.

- This solution could reduce number of unit processes and energy.

- Fouling rate of BG-MABR was found higher than that of BG-MBR (0.105 kPa/d and

0.027 kPa/d) (sludge concentration 2 g/L and 4 g/L for MBR and MABR).

- Specific energy was 0.1, 0.9 & 1.6 kWh/m3 for aerobic reactor, MBR & BG-MBR.

- OLR: MBR (< 8 kgCOD/m3.d) and BG-MBR (up to 15) kgCOD/m3.d.

4/40 B.X. Thanh - 10417314-Jan-09

Answers For Examiner’s Comments

- Proposed system is probably compact & less fouling potential compared to BG-MBR &

MG-MABR.

- Denitrification can be enhanced with a recirculation from membrane chamber to

settling chamber.

MBR chamber

Air supply

Permeate Effluent

SBAR

Setller-combined MBR

Up level

Down level

Sludge withdrawalSettlingchamber

Settler-combined MBR

Recirculation

5/40 B.X. Thanh - 10417314-Jan-09

Answers For Examiner’s Comments

5. To improve nitrogen removal & granular stability coupling to form a BG-MBR. This

combination induced a partial destruction of granules with appearance of fungi,

filaments & decreasing granular bed volume. Author attributes these phenomena to

the difficulty of control of optimal SRT (nevertheless, the quick variation of the

sludge composition did not correspond to the SRT).

- Granules disintegrated after a certain time of operation (about 300 days).

- Granule breakage occurred due to their long retention in SBAR (filaments & fungus).

- In granulation SBAR, the SRT was calculated by the conventional method as:

SRT = Sludge in reactor/sludge wasted out per day

- SRT calculated for granulation reactor is just a relative definition.

- Sludge washed out (< 10 m/h): light fraction (flocs, small granules, detached particles).

Granules retained in reactor

- Actual SRT = 10-15 d to avoid filaments Perform appropriate sludge removal

methods to control actual SRT to enhance granule stability. Periodical sludge

removal (a) mixed sludge; (b) top sludge; and (c) bottom sludge.6/40 B.X. Thanh - 104173

Answers For Examiner’s Comments

6. Result pointed out that the difficulty to achieve adequate nitrogen removal probably

link to the opposite conditions imposed by granulation and anoxic reduction of NOx

when NLR is too high. (A simulation with ASM model could indicate the adequate

time of aeration and non aeration to remove nitrogen and its conformity with

granular bed stability). Author should take some interest to ASM model to identify

the necessary time of aerobic/anoxic periods and the mass transfer through the

granule to remove nitrogen and compare the results to the optimal conditions to

maintain the structures of granule.

- For the proposed objectives, it needs to measure specific kinetic data, mass transfer

constants, mass transfer coefficients and active biomass for granule at various NLR,

OLR which have not planned in this research These objectives to be performed in

the future research.

7. Some corrections in chapter 3 has been corrected in the final version of Dissert.

B.X. Thanh

7/40 B.X. Thanh - 10417314-Jan-09

Background: Aerobic Granule

• Size: 0.5–9.0 mm Simultaneous nitrification/denitrification;

• Excellent settling ability (20-110 m/h, SVI = 18 mL/g)

• Tolerate temperature range (8-55oC) (De Kreuk et al., 2005);

• Microbial diversity;

• Remove phenol (3.8 kg/m3.day) (Tay et al., 2005)

and nitrilotriacetic (NTA) (Nancharaiah et al., 2006)

DO NO3-

CODNH4

+

Granule Bulk liquid

Anaerobic core

Aerobic layer

Carrier

8/40 B.X. Thanh - 10417314-Jan-09

Rationale: Aerobic Granulation MBR

Permeate

SBAR

MBR

AEROBIC GRANULE & MBR?

Aerobic Granule!

+Being popular due to cost reductionWater reuse and recycling; High SRT, MLSS & OLR less footprint;But fouling, sludge treatment, and oxygen transfer.

MBR

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Objectives of Study

1. Study on organic removal and simultaneous nitrification denitrification of aerobic granule and its stability in SBAR;

2. Characterize the fouling behavior of an external submergedMBR treating granulation SBAR effluent (BG-MBR) ;

3. Study on granule stability and fouling propensity of the Continuous Granulation MBR (CG-MBR) at various organic loading rate (OLR);

10/40 B.X. Thanh - 10417314-Jan-09

Overall Experimental Plan

Phase I a (AIT)

Batch granulation MBR(BG-MBR)

Aerobic Granulation MBR

Continuous granulation MBR(CG-MBR)

+ C, N removal+ Granule characterization+ Granule stability+ Fouling behavior

Phase I b (INSA)* Phase II (AIT)

SBAR

+ Effect of aeration rates(conventional vs granulation)

+ Effect of anoxic/aerobiccondition on sludge/effluentof SBAR

+ Granule stability;+ Effect of OLR on fouling,

N removal

*INSA = Institut National des Sciences Appliquées, Toulouse, France

SBAR

Settler

MBR

11/40 B.X. Thanh - 10417314-Jan-09

Batch Granulation MBR (BG-MBR): Phase Ia

Supernatant

SBAR

Cycle (4 hrs) Feeding High Aeration Low Aeration Settling WithdrawalTime (min) 6 198 30 3 3

SBAR:High aeration: 1.7 cm/sLow Aeration: 0.1 cm/sNLR: 0.6-1 kgN/m3.dOLR: 2 kg/m3.dShell carrier

MBR:Air flow: 0.3 cm/sFlux: 2.8 L/m2.hHRT: 3.4 hSRT: 20 dSuction: 7on/3off

MBRHollow fibre, PE

membrane area 0.42 m2

Permeate P

Air supply

12/40 B.X. Thanh - 104173

MBR

Timer

PLC

Level controller

SBAR

Settler

Feed tank

Air flow meter

PG

Suction pump

BG-MBR: Lab Scale Systems

B.X. Thanh

13/40 B.X. Thanh - 10417314-Jan-09

MBR & Measured Parameters

Soluble parameters:• TOC, Nitrogen species• EPS (PS, PN)• UVA254, SUVA (= UVA254/DOC)• Size Exclusion Chromatography (SEC-EEM)• Hydrophobicity

Sludge parameters:• MLVSS/MLSS• SVI• Capillary Suction Time (CST)• Microscopic Observation• Specific oxygen uptake rate (SOUR)

Membrane fouling parameters:• Modified Fouling Index (MFI) (SS, CL, SL)• Trans-membrane pressure (TMP)• Critical flux• Particle Size Distribution (PSD)• Resistance/Resistance rate

Hollow FibreMembrane Module

External Submerged MBR

14/40 B.X. Thanh - 10417314-Jan-09

Effect of Aeration Rates and Anoxic growth on SBAR effluent– Phase I b

Operating conditions:- SBAR: V = 17 L,

H = 1.07 m, D = 0.15 m

- OLR: 2.0-2.3 kgCOD/m3.d;- Batch: 6 h; 8 L/batch;- Cycle: Feeding: 30 min;

Reaction: 4h30min;Settling: 30 min; Discharge: 30min

- SRT: automatic washout;

Days38 790

Run I Run II Run III

0.8

2.2

0.6

Aeration rate (cm/s)

121

Introduce N2 gas

174

15/40 B.X. Thanh - 10417314-Jan-09

Continuous Granulation MBR (CG-MBR): Phase II

MBRHollow fibre

membrane module 0.42 m2

Air supply

Airlift reactor

System stop each 4 hr, settling 1 min

sludge discharge

Permeate P

sludge discharge(440 mL/4 h)

CG-MBR:Air supply: 1.7 cm/s (airlift);

0.1 cm/s (MBR)HRT: 10 hSRT: dependsFlux: 2.9 L/m2.hSuction: 7on/3offVolume 10 L (airlift)

3.5 L (MBR)

16/40 B.X. Thanh - 10417314-Jan-09

Operating Conditions: CG-MBR

RUN 1:OLR 2 kg COD/m3.dNLR 0.6 kg N/m3.d

OLR

RUN 2:OLR 4 kg COD/m3.dNLR 0.6 kg N/m3.d

RUN 3:OLR 8 kg COD/m3.dNLR 0.6 kg N/m3.d

Days50 880 120

17/40 B.X. Thanh - 10417314-Jan-09

BG-MBR Performance: Phase Ia

Page 53

Page 53

050

100150200250300350

Influent Settler MBRsupernatant

Permeate

TOC

(mg/

L)

104070100130160190220

TN (m

g/L)TOC TN

-50

0

50

100

150

200

250

Influent Settler MBRsupernatant

Permeate

conc

entra

tion

(mg/

L)

NH4-NNO2-NNO3-NTNSBAR: Organic removal & Partial Nitrification;

MBR: Nitrification & filtration;

18/40 B.X. Thanh - 10417314-Jan-09

Granule Characteristics in SBAR (Phase Ia)

14-Jan-09

Good settling (AS: < 10 m/h);High density & compact

Settling velocity (m/h)

500420

340260

180100

Freq

uenc

y

100

80

60

40

20

0

Mean: 131 m/hSD: 131N: 482

Granule size (mm)

876543

Freq

uenc

y

200

100

0

Mean: 4.68 mmSD: 1.35N: 500

Page 54

Page 54

B.X. Thanh

19/40 B.X. Thanh - 10417314-Jan-09

SBAR Performance – Organic Removal

050

100150200250300350

0 30 60 90 120 150 180 210 240

time (min)

TOC

(mg/

L)

0123456789

DO (m

g/L)

; pH

TOC DO pH

pH = 8.0 ± 0.2; DO = 4.0 – 7.8 mg/L;Organic matters are removed fast in 30 min (97.7 ± 1.4 %);

Page 51

20/40 B.X. Thanh - 10417314-Jan-09

SBAR Performance – Nitrogen Removal

0

40

80

120

160

200

0 30 60 90 120 150 180 210 240

time, min

conc

, mg/

L

NH4-N NO2-N NO3-N TN

+ Dynamic balance: NH4-N reduces NO2, NO3 N2 generated!

+TN removal 59% (SND= 47%, 22.2 mgN/L.h or 1.76 gN/gVSS.h);

SBARTNinf = 100%(190 mg/L)

TNeff = 41%(78 mg/L)

TNSND = 47%(89 mg/L)

Assimilation = 12%(23 mg/L)

TNremoved = 59% (112 mg/L)

Page 51

Page 52

21/40 B.X. Thanh - 10417314-Jan-09

Membrane Fouling Behavior: Phase Ia

Fouling propensity of sludge fractions: Suspended Solids (SS), Colloids (CL) & Solutes (SL)

012

3456

78

0 25 50 75 100 125 150 175 200V, mL

t/V, s

/mL

SS-CL-SL CL-SLSL

Fouling potential of SS, CL & SL were 12%, 39% & 49%;Resistance percentage of SS, CL & SL were 2, 12 & 86 %;

Soluble matters is the major fouling contributor

Page 58

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Membrane Fouling – Soluble Fractions

0

5

10

15

20

settler MBR Permeate

conc

entr

atio

n (m

g/L)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

soluble PS soluble PNPS/EPS ratio

• Soluble PS increased in MBR (cell lysis, deflocculation)• PS/EPS > 0.8;• Soluble PS & PN deposited on membrane (11 mgPS/L.m2 & 8 mgPN/L.m2);• Soluble EPS extracted from membrane fibres: 20 µg/cm2 (after 78 days)

Release Deposition

Page 60

23/40 B.X. Thanh - 10417314-Jan-09

0

50

100

150

200

250

0 30 60 90 120 150 180day

SV

I (m

l/g)

0

2

4

6

8

10

MLS

S (g

/L)

SVI30 MLSS0.8 cm/s 2.2 cm/s 0.6 cm/s

N2 introduced

• Biomass conc. & settling ability increased impressively (SVI = 44 mL/g);• Anoxic growth improves aggregate density & promote aggregation;• Average effluent SS from SBAR reduced at Run III (200 to 50 mg/L).

Sludge characteristics

Effect of Aeration Rates & Anoxic growth on SBAR Effluent– Phase I b

200 µm200 µm

Page 68

24/40 B.X. Thanh - 10417314-Jan-09

Rt = ∆P/(J*µ)

0.00E+00

1.00E+12

2.00E+12

3.00E+12

4.00E+12

5.00E+12

0 40 80 120 160 200 240 280V (mL)

Rm

+Rf (

1/m

)

0.0E+00

4.0E+08

8.0E+08

1.2E+09

1.6E+09

0 0.25 0.5 0.75 1 1.25 1.5Pressure (bar)

dR/d

V (m

-1*s

-1)

Resistance Rate Calculation– Phase I b

B.X. Thanh

25/40 B.X. Thanh - 10417314-Jan-09

0.0E+00

5.0E+12

1.0E+13

1.5E+13

2.0E+13

0 0.25 0.5 0.75 1 1.25 1.5

dR/d

V (1

/m.L

)

SS-CL-SLCL-SLSL

0.0E+00

5.0E+12

1.0E+13

1.5E+13

2.0E+13

0 0.25 0.5 0.75 1 1.25 1.5

dR/d

V (1

/m.L

)

0.0E+00

5.0E+12

1.0E+13

1.5E+13

2.0E+13

0 0.25 0.5 0.75 1 1.25 1.5Pressure (bar)

dR/d

V (1

/m.L

)

0.8 cm/s 2.2 cm/s

0.6 cm/s + Anoxic/aerobic • At low aeration rate (0.8-0.6 cm/s):Resistance rates (SS, CL, SL) same order of magnitude;

• At high aeration rate (2.2 cm/s): resistance rates increases & resistance of SS plays a significant role release of small particles & SMPs.

• With anoxic: resistance slightly increases.

SS = 334 mg/L SS = 474 mg/L

SS = 97 mg/L

Resistance Rate in SBAR Effluent: Phase I b

Page 69

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0.0E+00

4.0E+11

8.0E+11

1.2E+12

Res

ista

nce

(1/m

)

0.0E+00

4.0E+11

8.0E+11

1.2E+12

Res

ista

nce

(1/m

)

0.0E+00

4.0E+11

8.0E+11

1.2E+12

Rf Rir Rrev

Res

ista

nce

(1/m

)

SS = 334 mg/L SS = 474 mg/L

SS = 97 mg/L Same trend as fouling rate;

• High aeration rate increasesirreversible fouling;

• Anoxic growth also increases irreversible fouling (due to soluble)

0.8 cm/s

2.2 cm/s

0.6 cm/s + Anoxic/aerobic

Irreversible/Reversible Resistance in SBAR Effluent: Phase I b

Reduction of aeration and improvement of denitrification leads to lower irreversible fouling

Page 70

27/40 B.X. Thanh - 10417314-Jan-09

Source SBAR Effluent SBAR Sludge

Aeration rate 0.8 cm/s 2.2 cm/s 0.6 cm/s + ano/aero 2.2 cm/s 0.6 cm/s C (kgSS/m3) 0.334 0.474 0.097 3.160 4.750Specific cake resistance - α(1012 m/kg) 27.2 20.1 214.0 7.5 1.6

An inverse trend for “Sludge” & “Effluent” behavior during filtration:

- Anoxic growth seems to have a negative impact on effluent (SMP)but a positive role on sludge filtration (aggregate densification).

- Specific cake resistance (α ) is always lower for Sludge than Effluent (due to particles properties and role of soluble)

Comparison of Specific cake resistance of Effluent & Sludge: Phase I b

Page 71

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Size exclusion chromatography (SEC) shows :

• Macromolecules (40-600 kDa) are increasingly produced at high aeration rate (2.2 cm/s),

• Compounds from 5.7- 6.2 kDa were especially released during denitrificationintensification (anoxic growth) and granular sludge formation

Characterization of soluble compounds by Chromatography

Hydrophobic Interaction Chromatography (HIC) shows :

• At high aeration rate, Supernatant in effluent contained larger (60%)hydrophobic fraction with low hydrophobic intensity;

• At low aeration rate with anoxic growth, supernatant in effluent contained lesshydrophobic fraction (20%) with high hydrophobic intensity.

Soluble Matters Characteristics: Phase I b

29/40 B.X. Thanh - 10417314-Jan-09

Continuous Granulation MBR (CG-MBR): Phase II

0

20

40

60

80

100

0 20 40 60 80 100 120Day

Rem

oval

effi

cien

cy (%

)

0

1

2

3

4

5

OLR

(kgT

OC

/m3.

d)

TNDOCLoading

0

10

20

30

40

50

0 20 40 60 80 100 120Day

NO

2-N

and

NH

4-N

(mg/

L)

0

40

80

120

160

200

NO

3-N

(mg/

L)

NH4-N NO2-N NO3-N

+ Granule disintegrate CG-MBR=conventional MBR;+ TOC removal: 97.8, 99.0 & 99.4 % at OLR 2, 4, 8;+ TN removal: 20, 30 & 53%;+ Granule breakage TN removal reduced;

+ NO3 reduced, NO2, NH3increased at OLR 8;

+ Nitrifying activity ↓ at high OLR not compete with heterotrophs

Granule break

Page 75

Page 75

30/40 B.X. Thanh - 104173

0

20

40

60

0 10 20 30 40 50 60Day

TMP

(kPa

)

OLR 2OLR 4OLR 8

14-Jan-09

Fouling Propensity of CG-MBR: Phase II

+ Cake build-up TMP “jump”+ Cake resistance > 87.5 %

Fouling rate (kPa/d)

Cake build up

Page 78

y = 4.67x2 - 7.94x + 3.47R2 = 1.00

y = 3.03x - 1.50R2 = 0.94

y = 8.15x - 4.06R2 = 0.97

0.0

0.5

1.0

1.5

2.0

2.5

0 0.5 1 1.5 2F/M (1/d)

Foul

ing

rate

(kPa

/d)

0

2

4

6

8

10

Load

ing

rate

(kg/

m3.

d)Fouling rate

TOC loading

COD loadingPage 78

+ Fouling rate proportional to F/M ratio (2rd order); OLRs (1st order);+ Membrane contacts with high amount of organic matters fouling.

B.X. Thanh

31/40 B.X. Thanh - 10417314-Jan-09

0

10

20

30

40

0 20 40 60 80 100 12Day

Perm

eate

(mg/

L)

PSPNDOC

Behavior of Soluble Matters in CG-MBR

0

10

20

30

40

0 20 40 60 80 100 120Day

Supe

rnat

ant (

mg/

L)

PSPNDOC

+ Soluble matters (DOC, Polysaccharides, Protein): (Supernatant > Permeate!) deposited on membrane ;

Deposition rates (mg/L.m2

membrane)OLR (kgCOD/m3.d)

2 4 8DOC 16.3 18.2 17.2sPS 13.1 11.3 13.7sPN 5.6 5.0 6.7sEPS 18.7 16.3 20.5

Page 79 Page 79

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Comparison: BG-MBR vs CG-MBR

0

20

40

60

BG-MBR CG-MBR

TN re

mov

al (%

)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Foul

ing

rate

(kPa

/d) &

F/M

(1/d

)

TN removalFouling rateF/M

+ Granule was instable in CG-MBR higher F/M, higher fouling and lower N removal.

+ Granule stuck on the membrane fibres (lack shear stress) Flatsheet module is suitable for granulation MBR!

Page 80

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Comparison: Treatment Systems

Items Anaerobic reactor Submerged MBR BG-MBROperating temp. (oC) 30-55 25-35 8-55Energy requirement (kWh/m3)

0.1 0.9 1.6

Sludge failure Possible - Possible Shock load resistance Possible - YesStart-up time (days) 100 10 30MLSS (g/L) 2-60 (depends) 8-15 Up to 18 g/L (2-4 g/L: MBR)SRT (day) 10-300 15-30 10-100*SVI (mL/g) 10-280 120-250 mL/g 10-40 mL/gSettling velocity (m/h) < 10 < 10 20-100 (higher for granule)Particle size (µm) 0.5-8.0 mm (granule)

0.3-200 (flocs)1-250 (flocs) 0.5-9.0 mm (granules)

0.3-301.7 (flocs in MBR)OLR (kg COD/m3.d) Up to 40 < 8 2-30SND No Possible Good (1.76 mgTN/gVSS.h)Fouling potential - High (0.168 kPa/d) Less (0.027 kPa/d)

BG-MBR shows the potential application for high strength C, N wastewater

Page 82

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Conclusions

+ BG-MBR system:

+ Ability for C & N removal. The SND at OLR of 2 kgCOD/m3.d was 47% or 22 mgTN/L.h (1.76 mgTN/gVSS.h).

+ Aerobic granules disintegrated under anaerobic condition and long SRT.

+ Release of soluble matters in MBR depends on the HRT which influences the fouling propensity & supernatant quality. SMPs are the main cause for fouling where polysaccharides were dominant (11 mg/L.m2 & 8 mg/L.m2

for sPS & sPN).

+ The disintegration of granules resulted in the release of SMPs that increased the fouling propensity of the BG-MBR system

CG-MBR system:+ Granule is disintegrated in continuous operation mode (CG-MBR);

+ Fouling rate showed 2rd order increment with F/M ratio & 1st order with OLR.

+ SMPs deposited on membrane.

35/40 B.X. Thanh - 10417314-Jan-09

Conclusions (cont’d)

Effect of aeration rates:

+ The anoxic/aerobic conditions enhanced the biomass retention, settling ability, denitrification & filterability.

+ Resistance rate & specific cake resistance of SBAR effluent were higher than that of sludge in anoxic/aerobic operation despite higher SS.

+ Resistance & irreversible resistance of SBAR effluent were increased at high aeration rate (2.2 cm/s) due to release of macromolecules (30-50 kDa) & small particles while SMPs were released at lower aeration rate (0.8 cm/s).

+ At high aeration rate (2.2 cm/s), 60% of the hydrophobic fraction was found in the soluble fraction of SBAR effluent with low hydrophobic intensity. While at the low aeration rate (0.6 cm/s + anoxic growth), 20% of the hydrophobic fraction was found with high hydrophobic intensity.

+ BG-MBR showed better operational performance than CG-MBR (granule stability, N removal & fouling propensity).

+ Higher biomass retention in BG- MBR compared to CG-MBR lower F/M lower fouling.

36/40 B.X. Thanh - 10417314-Jan-09

Recommendations

+ Study on the granule stability at various SRT & sludge removal methods (mixed sludge, top sludge, & bottom sludge).

+ To accelerate and stabilize the granulation process, methods namely support media addition, bridging polymer addition, aeration rates, cycle length, etc should be investigated and optimized.

+ In BG-MBR, HRT of MBR affects the release of SMPs relates fouling Investigate fouling and sludge characteristics at various HRT.

+ Study on the possibility of granulation and fouling characteristics in sequencing batch MBR in which membrane functions as an ideal decanter in a SBR. The light fraction of sludge is removed periodically (feast/famine).

+ SMPs played an important role in fouling of granulation MBR study on the quality and quantity of soluble fraction through SEC-EEM-DOC for understanding the nature of foulants at certain operating conditions

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Recommendations (Cont’d):Proposed Batch Granulation-MBR

Air supply

Permeate Effluent

SBAR

Setller-combined MBR

Up level

Down level

Sludge withdrawalSettlingchamber

MBR chamber

Settler-combined MBR

Recirculation

+ Investigate compacted BG-MBR which membrane is integrated in an aerated zone of settler.

+ Recirculation ratio from aeration zone to settling zone can improve further N removal.

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Recommendations (Cont’d):Proposed CG-MBR

+ Study on the application of flat-sheet membrane in CG-MBR. This semi-continuous system can maintain granule stability

(Sludge discharge interval 1-4 h,to control feast-famine condition).

P

Sludge discharge pump (each 4 h)

Influent pump (continuous)

Permeate pump (on/off cycle)

Flatsheet membrane

module

Air scouring

Air supply

Level sensor

Granules

Remark: Granulation Membrane Airlift BioreactorEach 4 h, system stops and sludge settling for 1-2 minute

sludge discharge

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Publications

Thanh, B.X., Visvanathan, C., Spérandio, M., Ben Aim, R. (2008). Fouling characterization in aerobic granulation coupled MBR, Journal of Membrane Science, 318 (1-2), 334-339.

Thanh, B.X., Visvanathan, C., Ben Aim, R. (2009). Characterization of aerobic granules at various organic loading rates, Process Biochemistry, 44, 242-245.

Thanh, B.X., Visvanathan, C., Ben Aim, R. (Submitted). Fouling behavior in external submerged MBR treating granulation effluent, Separation Purification and Technology.

Thanh, B.X., Sperandio, M., Guigui, C., Ben Aim, R., Wan, J.F., Visvanathan, C. (2008). Coupling SBAR and membrane filtration: Influence of nitrate removal on sludge characteristics, effluent quality and filterability, Conference on Membranes in Drinking Water Production and Wastewater Treatment, Oct 20th-22nd, 2008, Toulouse, France.

Jegatheesan, V., Shu, L., Visvanathan, C., Thanh, B.X. (2008). Aerobic Environmental Process: Chapter 23 in Advances in Fermentation Technology, Ed. Pandey et al., pp. 622-654, Asiatech Press, New Delhi. ISBN: 81-87680-18-0.

Journal Publications:

Book chapter:

IWA International Conferences:

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Thank you for your attention!