19 - 20 October 2010

Paper – A Sustainable Business

Engineered Water Treatment Solutions

Treatment of Recycled Paper Mill Effluent using Membrane Bioreactors

Nampak Tissue Case-Study

Wade Edwards*, Peet Zeelie, Marshall Sheldon

Engineered Water Treatment Solutions

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Global water crisis – 40% supply/demand gap by 2030

Agricultural demand - decrease from 71% - 65% of overall demand

Domestic demand - decrease from 14% - 12% of overall demand

Industrial demand – INCREASE from 16% - 22% of overall demand

Economic Evaluation: Water Reuse and Recycle

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18% supply/demand gap by 2030 (historical trend)

30% supply/demand gap by 2030 (climate change)

National ‘Green Drop’ initiative – 3% of WWTPs are 90% compliant

70% increase in cost of water in past 5 years

6,000Ml per month of polluted industrial effluent is discharged

Cost-to-industry R760 million/year

South African Situation

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R 5.00

R 5.50

R 6.00

R 6.50

R 7.00

R 7.50

R 8.00

R 8.50

R 9.00

Nov-07 Feb-08 Jun-08 Sep-08 Dec-08 Mar-09 Jul-09 Oct-09 Jan-10

Month / year

Cos

t per

kL

(ZA

R)

Water cost (R/kL) Effluent cost (R/kL)

20%

13%

Physical

Biological

Cleaner Production

Technical Solutions & Strategies

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Compliance with discharge standards

Reduction in effluent discharge tariffs

Reduction in fresh water consumption

Integration with Cleaner Production & Waste Minimisation

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Economic Viability Assessment

R 0

R 100,000

R 200,000

R 300,000

R 400,000

R 500,000

R 600,000

R 700,000

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000

Final COD (mg/L)

Mo

nth

ly E

fflu

ent

Ch

arg

e

Raw effluent R583,000

Treated effluent

R258,000 CAPEX R6,000,000OPEX R12,000/monthRoI 18 months

Company – Simba Chips, BellvilleContractor – Project AssignmentsWater recycle - No

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Economic Viability Assessment

Biological Treatment

Aerobic Anaerobic

Suspended GrowthFixed Film

Trickling filter

FluidizedBed

BAFReed Beds

Suspended GrowthFixed Film

Anaerobic filter

FluidizedBed

Submerged anaerobic

filter

Anaerobic Contact process

UASB ABR

Sludge digestion

SAFRBC MBBR

Activated sludge

Aerated lagoons

Ponds

PACTContact

stabilisationMembranebioreactors

BNR SBR Deep shaft

A2O UCT VIP MLE Bardenpho Step feed ??

IC

Biological Treatment Processes

°

°°

°°

°

°°

°

°

Mechanical pre-treatment

Activated sludge tankSubmerged MBR

°

°°

°°

°

°°°

°

Denitrification NitrificationWastewater

Cleaned Wastewater

B

°

°°

°°

°

°°

°

°°

°°

°°

°

°°°

°

Activated sludge tank

Denitrification NitrificationPre-clarification

Mechanical pre-treatment Secondary clarification Disinfection

Wastewater Cleaned Wastewater

Conventional activated sludge

Submerged MBR

°

°°

°°

°

°°

°

°

Mechanical pre-treatment

Activated sludge tankSidestream MBR

Wastewater

Cleaned Wastewater

A

Sidestream MBR

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Membrane Bioreactor Process

1 2 3

4

7

6 5

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Membrane Bioreactor Process

OPEXOLR = 3,000kg BOD/day

C:N:P ratio = 100 : 0.3 : 0.08

Q = 1.2Ml/d N supp. = R645,000 / year

P supp. = R235,500 / year

R880,500 / year

C:N:P ratio 100:10:1

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Process Design Considerations

PHYSICO-CHEMICAL PARAMETERS

INORGANIC COMPOSITION

Na mg/L 162K mg/L 9Ca mg/L 365Mg mg/L 15Fe mg/L 0.26Cl mg/L 141CO3 mg/L N/A

HCO3 mg/L 1,018

SO4 mg/L 454

B mg/L 1.15Mn mg/L 0.06Cu mg/L 0.002Zn mg/L 0.15F mg/L 0

DESIGNPARAMETERS

BOD/COD ratio = ±0.85

COD/BOD ratio = 1.15

OLR = 3,000kg BOD/d

SO4/COD ratio = 0.15

C:N:P ratio = 100 : 0.3 : 0.08

pH pH units 6.44 (4.4 - 6.8)Temperature Cº 37

Conductivity (µS/cm) 1,845 (1,203 - 2,530)

TDS mg/L 1,185 (457 - 1,760)Turbidity NTU 220 (61 - 868)COD mg/L 2,950 (1,362 - 4,481)BOD mg/L 2,400

TSS mg/L 124 (19 - 447)

NH4-N mg/L 5.18 (3.9 - 7.1)

NO3-N mg/L 5P mg/L 2.3

C:N:P ratio = 100 : 10 : 1

Q = 1.2Ml/d

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Summary – Effluent Composition

ANOXIC

ANAEROBIC

AEROBIC

KEY:

FEED

ANAEROBIC ANOXIC AEROBICMEMBRANEFILTRATION

PRODUCT

EGSB Modified Ludzack-Ettinger (MLE)

5Q RECYCLE

Process Design Strategy

21

1 2

3

4

43

5

5

6

6

Piloting – Anaerobic & MBR

Anaerobic pre-treatment

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

0 20 40 60 80 100 120

Operating Days

CO

D (

mg

/L)

0

20

40

60

80

100

Product COD Permeate COD

Effluent COD Overall COD removal

CO

D r

emo

val (

%)

Aerobic MBR post-treatment

70% COD reduction0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

0 50 100 150 200

Operating Time (days)

CO

D (

mg

/L)

0

20

40

60

80

100

CO

D R

emo

val (

%)

Effluent COD Product COD COD Removal

START-UP

98% COD reduction

MBR DURATION

Pilot Plant – NF & RO

Parameter Units Effluent MBR NF % MBR % Overall

Conductivity µS/ cm 1,380 940 70 32 94.9

TDS mg/ L 1,038 711 51 32 95.1

COD mg/ L 2,105 40 19 98 99.1

Parameter Units Effluent MBR NF % MBR % Overall

Na mg/ L 110 118 11.3 N/A 89.7

Ca mg/ L 250 79 3 68 98.8

Mg mg/ L 9.6 10 0.3 N/A 96.9

Cl mg/ L 57 79 9.7 N/A 82.8

HCO3 mg/ L 763 338 10.7 56 98.6

SO4 mg/ L 345 72 6 79 98.3

PHYSI CO- CHEMI CAL PARAMETERS

I NORGANI C COMPOSI TI ON

Parameter Units Effluent MBR RO % MBR % Overall

Conductivity µS/ cm 2,100 980 94.2 53.3 95.5

TDS mg/ L 1,587 743 69.7 53.2 95.6

COD mg/ L 2,280 58 6 97.5 99.7

Parameter Units Effluent MBR RO % MBR % Overall

Na mg/ L 110 104.4 12.8 5.1 88.3

Ca mg/ L 433 82.46 4.7 80.9 98.9

Mg mg/ L 11.2 10.44 0.4 6.8 96.3

Cl mg/ L 74.9 73.14 15.0 2.3 80.0

HCO3 mg/ L 1,100 651 38.2 40.8 96.5

SO4 mg/ L 133 86.08 15.2 35.3 88.5

PHYSI CO- CHEMI CAL PARAMETERS

I NORGANI C COMPOSI TI ON

Nanofiltration polishing

Reverse osmosispolishing

99.1% COD reduction

98.8% Ca reduction

98.6% HCO3 reduction

99.7% COD reduction

98.9% Ca reduction

96.5% HCO3 reduction

Process Design – Side-stream MBR

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Process Design – Immersed MBR

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Asia73%

Europe16%

North America11%

0

100

200

300

400

500

600

1997 1998 1999 2000 2001 2002 2003 2004 2005

Me

mbr

an

e su

rfa

ce a

rea

(x

100

0m2 )

Industr ial

Municipal

0

50

100

150

200

250

300

350

1997 1998 1999 2000 2001 2002 2003 2004 2005

Nu

mb

er

of M

BR

in

sta

llati

ons Industrial (>20m3/day)

Municipal (>500p.e)

MBR Market Distribution & Segmentation

0

50

100

150

200

250

300

350

400

450

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Mem

bran

e co

st (

€/m

2)

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MBR – Cost of Operation

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91% decrease in OPEX

Anaerobic Process Design – UASB/IC

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UASB/EGSB / IC

Anaerobic Process Design – ABR

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Anaerobic Baffled Reactor

Economic Viability Assessment

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Influent COD (mg/L))

En

erg

y (k

Wh

/d)

-100

100

300

500

700

900

1,100

CH

4 p

rod

uce

d (

Nm

3 /d)

Energy Produced kWh/d Net energy kWh/d CH4 produced Nm3/d

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Influent COD (mg/L))

En

erg

y (k

Wh

/d)

-100

100

300

500

700

900

1,100

CH

4 p

rod

uce

d (

Nm

3/d

)

Energy Produced kWh/d Net energy kWh/d CH4 produced Nm3/d

NOTE:• Anaerobic gas content = 75.5% CH4

• Maximum CH4 production is 0.35Nm3 CH4 per kg COD removed• Calorific heat value of methane = 32MJ/Nm3 CH4

• 1kWh = 3.6MJ

70%

Anaerobic COD removal efficiency & methane production (75.5% CH4)

Net 3,000kWh/d (22,500MJ/d)

Net 4,000kWh/d (27,400MJ/d)

85%

Process Segmentation - Anaerobic

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Process Segmentation - Anaerobic

Anaerobic systems per sector

Anaerobic system type distribution

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Conclusions

ANAEROBIC PRE-TREATMENT

• Reduces biological loading on MBR – 70% COD reduction• Lowers energy requirements, operating costs, and sludge production• 0.35Nm3 CH4/kg COD removed; 32MJ/Nm3 CH4

MEMBRANE BIOREACTOR

• MBR – 98% overall COD reduction; 99% TSS reduction• Integrated pre-treatment for NF or RO

EFFLUENT POLISHING (NF & RO)

• 95% overall TDS reduction; 98% Ca reduction; 96% HCO3

Conclusions

R 0

R 2,000

R 4,000

R 6,000

R 8,000

R 10,000

2007-2008 2008-2009 2009-2010 2010-2011

Financial year

Co

st -

R('

000)

0.5Ml/d 1.0Ml/d 1.5Ml/d 2.0Ml/d 2.5Ml/d

Annual potable water intake costs

R 0

R 1,000

R 2,000

R 3,000

R 4,000

R 5,000

R 6,000

R 7,000

2007-2008 2008-2009 2009-2010 2010-2011

Co

st -

R('

000)

0.5Ml/d 1.0Ml/d 1.5Ml/d 2.0Ml/d 2.5Ml/d

Annual effluent discharge costs

Potable 1.0Ml/day – R3.3 million/yrEffluent 1.0Ml/day – R2.5 million/yr

Potable 2.0Ml/day – R3,3 million/yrEffluent 2.0Ml/day – R6.6 million/yr

CAPEX – ROI of 3 years

OPEX savings – 85%

Acknowledgements

Water Research Commission of South Africa

Nampak Tissue

Engineered Water Treatment Solutions

www.atl-hydro.com

Thank you

Dr Wade Edwards Managing Director+27 (0) 83 441 0450 wade.edwards@atl-hydro.com

Dr Marshall Sheldon Director of Operations+27 (0) 72 485 3171

marshall.sheldon@atl-hydro.com