Membrane Bioreactor Pilot Plant Operating Experience

Pardi SukapanpotharamBob Bucher

King CountyTechnology Assessment Program

Impact of Mixed Liquor Characteristics on Filtration

Presentation Objectives

Share the experience of operating a pilot MBR plant. Present water quality and

biological process parameters and corresponding filtration performance.

Pilot Information Pilot provided by Enviroquip, Inc. Pilot equipped with Kubota plate

membranes. Operated at the West Point

Treatment Plant from 2004 – 2006. Total process volume of 9,000 gal Treatment capacity of 40,000 gal/d

Membrane Specifications

200 plates (EW 200) Surface area = 13.45 ft2/plate Nominal net flux = 14.7 gfd Nominal pore size = 0.4 micron Effective pore size = 0.1 micron

Pilot Process Flow Diagram

Feed

EffluentSample

AnoxicAerobic/

Membrane

2 mm bandscreen

Turbidimeter

Filtrate

WasteSludge

Blower

C

6 mmscreen

S50S54

S53

S52

S51

Pre-Aeration

Mixed Liquor Recycle (via gravity flow)

C

Pilot Installation

Pilot Operating Conditions Nominal net flux = 14.7 gfd Relax frequency = 9 min Relax duration = 1 min Specific air scour = 0.017-0.026 scfm/ft2

MLSS = 8,000 – 15,000 mg/L ML recycle ratio = 2 – 6 Feed = primary influent or primary

effluent

Testing Phases Baseline Long term flux increase (125% of

nominal flux for 1 month) Diurnal flow 24-hrs peak event 72-hrs peak event Polymer addition

Disruptions in Pilot Operation Process re-seeding Revisions to membrane control logic Inspection of membrane cartridges Replacement of membrane cartridges Replacement of ML recycle pumps Replacement of aeration blowers Loss of power to West Point pilot facility

Operational Comparison(MBR vs. CAS)

Both rely on good biological process control Physical barrier vs. gravity settling Loss of treatment capacity vs. solids

carry-over MBR parameters:

•Flux = flow/area (gal/ft2/d)•TMP = trans membrane pressure (psi)•Permeability = flux/TMP (gfd/psi)

Membrane Fouling Reduction of pore size or effective filtration

area Additional energy required to pull water

through the membrane characterized by:• Increase in trans membrane pressure (TMP)• Decrease in permeability (flux/TMP)

Increases over time Response to fouling:

• Increase relax frequency• Increase air scour• Chemical cleaning

Factors Impacting Characteristics of Biological Process Solids (ML)

Feed characteristics Process Temperature DO pH Hydraulic retention time Solids retention time

Biological Parameters Impacting Membrane Fouling Potential

Mixed liquor concentration Viscosity Temperature Soluble microbial products (SMP) Colloidal material

MBR Process Optimization

Biological Membrane

Pilot Biological Process Monitoring Parameters

SRT MLSS/MLVSS sCOD Temperature pH DO F/M

Nitrification Filterability Specific Oxygen

Uptake Rate Microscope

Inspection

Pilot Membrane Process Monitoring Parameters

TMP/Permeability Air scour flow Effluent turbidity Cycle length (permeate/relax) Recycle flow Permeate flow Temperature

Pilot Field Testing Filterability (Time to Filter) Viscosity Capillary Suction Test (CST) DO Temperature pH Specific Oxygen Uptake Rate (SOUR) Visual inspections (air scour)

MBR Pilot Data Sample

MBR Pilot Data Review(Mixed Liquor Suspended Solids)

0

5

10

15

20

25

30

35

40

45

5019

-Jul

-05

21-J

ul-0

5

23-J

ul-0

5

25-J

ul-0

5

27-J

ul-0

5

29-J

ul-0

5

31-J

ul-0

5

2-A

ug-0

5

4-A

ug-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

MLS

S (m

g/L)

Lower deck permeabilityUpper deck permeabilityMLSS (mg/L)

MBR Pilot Data Review(Permeability and SOUR)

0

10

20

30

40

50

605-

Oct

-05

25-O

ct-0

5

14-N

ov-0

5

4-D

ec-0

5

24-D

ec-0

5

13-J

an-0

6

2-Fe

b-06

Date

SOU

R (m

g/gV

SS/h

r)

Per

mea

bilit

y (g

fd/p

si)

SOURLower PermeabilityUpper Permeability

Pilot Operating Conditions for Data Presented in Following Slides

Sep 18 – Dec 8, 2005 •Average Temp = 18ºC (13-22ºC)•Average Air Scour = 0.022 scfm/ft2•Average Flow = 28 gpm•Average MLSS = 12,000 mg/L

MBR Pilot Data Review( F/M )

020

4060

8010

012

014

05-

Sep-

05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-No

v-05

14-N

ov-0

5

24-N

ov-0

5

4-De

c-05

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

F/M

ratio

(1/d

ay)

Lower PermeabilityUpper PermeabilityF/M ratio

cleaningFlow = 20 gpm

MBR Pilot Data Review( SRT )

020

4060

8010

012

014

05-

Sep

-05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

0

5

10

15

20

25

30

35

SRT

(day

s)

Lower Permeability

Upper Permeability

SRT

MBR Pilot Data Review( Filterability )

020

4060

8010

012

014

05-

Sep

-05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

0

2

4

6

8

10

12

14

16

18

20

Filte

rabi

litly

(mL/

5min

)

Lower Permeability

Upper Permeability

Filterability

MBR Pilot Data Review( sCOD )

0

20

40

60

80

100

120

1405-

Sep

-05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

Lower Permeability Upper Permeability sCOD in mixed liquor

MBR Pilot Data Review( CST )

020

4060

8010

012

014

05-

Sep

-05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

0

5

10

15

20

25

30

35

Cap

illar

y Su

ctio

n Te

st (s

ec)

Capillary Suction Test

Upper Permeability

Filterability

MBR Pilot Data Review(Nitrification)

0

20

40

60

80

100

120

1405-

Sep-

05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)

Lower Permeability (gfd/psi)Upper Permeability (gfd/psi)Ammonia Removal

MBR Pilot Data Review(COD Removal)

0

20

40

60

80

100

120

140

5-Se

p-05

15-S

ep-0

5

25-S

ep-0

5

5-O

ct-0

5

15-O

ct-0

5

25-O

ct-0

5

4-N

ov-0

5

14-N

ov-0

5

24-N

ov-0

5

4-D

ec-0

5

14-D

ec-0

5

Date

Perm

eabi

lity

(gfd

/psi

)CO

D re

mov

al (%

)

Lower Permeability (gfd/psi)Upper Permeability (gfd/psi)COD Removal

Membrane Fouling Control

Decrease flux Increase specific air scour Increase relax frequency Increase chemical cleaning

frequency Polymer addition

Membrane Fouling Control (Flux Decrease)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 2 4 6 8 10 12 14 16

Flowrate (gfd)

TMP

(psi

)

Air = 0.02 scfm/sfTemp = 11 CMLSS = 11,767 mg/L

Membrane Fouling Control (Pilot Example – Flux Decrease)

Dec 15, 05

0

5

10

15

20

25

30

35

12/1

5/05

19:

12

12/1

5/05

19:

26

12/1

5/05

19:

40

12/1

5/05

19:

55

12/1

5/05

20:

09

12/1

5/05

20:

24

12/1

5/05

20:

38

12/1

5/05

20:

52

12/1

5/05

21:

07

12/1

5/05

21:

21

12/1

5/05

21:

36

12/1

5/05

21:

50

12/1

5/05

22:

04

12/1

5/05

22:

19

12/1

5/05

22:

33

12/1

5/05

22:

48

12/1

5/05

23:

02

12/1

5/05

23:

16

12/1

5/05

23:

31

12/1

5/05

23:

45

12/1

6/05

0:0

0

Time

Flow

(gpm

) & T

MP

(psi

)

Lower flow (gpm)Upper flow (gpm)lower TMPupper TMP

Membrane Fouling Control (Air Scour Rate Increase)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 2 4 6 8 10 12 14 16

Flowrate (gfd)

TMP

(psi

)

0.02 scfm/sf0.014 scfm/sf

Membrane Fouling Control(Pilot Example -Polymer Addition)

0

10

20

30

40

50

60

70

80

901/

17/0

6 9:

36

1/17

/06

10:4

8

1/17

/06

12:0

0

1/17

/06

13:1

2

1/17

/06

14:2

4

1/17

/06

15:3

6

Perm

eabi

lity

(gfd

/psi

)

Lower PermeabilityUpper permeability

Before Polymer AdditionFilterability = 1.6 ml/5min

After Polymer AdditionFilterability = 20 ml/5min

Presentation Summary During piloting, several parameters were

typically changing at the same time – difficult to establish performance relationships.

Membrane fouling will occur under all operating conditions.

Multiple parameters must be monitored simultaneously for troubleshooting and maintenance of filtration process.

Need to find practical methods for utilizing membrane fouling research data.

Acknowledgements Kubota Membrane Corporation

Enviroquip, Inc.

West Point Treatment Plant Staff

King County Environmental Lab Staff

Membrane Bioreactor Pilot Plant Operating Experience

Pardi SukapanpotharamBob Bucher

King CountyTechnology Assessment Program

Impact of Mixed Liquor Characteristics on Filtration