1

THE MIDDLE EAST DESALINATION RESEARCH CENTER

Sulnate of Oman ONEP (Morroco)

1- GEPEA, UMR CNRS 6144, France2- Chemistry dept., LACHIMIA, U. de Dakar, Senegal3- Veolia Water, Anjou Recherche, France4- ONEP, Morocco5- MEDRC, Muscat, Sulnate of Oman

INTENSIFICATION OF BRACKISH WATERS DESALINATION USING NANOFILTRATION (NF)

IN THE PLACE OF REVERSE OSMOSIS (RO)Case studies in Morocco and in Senegal

Maxime PONTIE1, Hanane DACH1,2, Pascal JAOUEN1, Courfia DIAWARA3, Jérôme LEPARC4,

Mohamed HAFSI4, Nourredine GHAFFOUR5

3rd Oxford Water and Membranes Research Event – September 12th - 15th 2010, Lady Margaret Hall, The University of Oxford (UK)

www.gepea.fr

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Objectives

Evaluate, at a pilot scale, the possibilities to produce drinking water by NANOFILTRATION (NF) from brackish groundwaters contaminated with F- ;

Compare the performances of NF vs reverse osmosis (RO)in terms of water productivity , membrane efficiencyvs salts rejection and energy consumption ;

Help to develop local « membrane » activities by research teams in MOROCCO and in SENEGAL.

3

0

10

20

30

40

1965 1975 1985 1995 2005

Introduction

Inta

lled

capa

city

(bill

ions

lite

rs/d

ay)

Years

(from Arabi M. A., “Desalination growth in the MENA r egion”Arab water world, sept.-oct. 2003 - 36 (5) 56)

51%

33%

8%4%

4%

RO

MSF

MED & VC

ED

NF

Installed capacity by process (IDA Desalination Yearbook, 2007)

Brackish waters desalination market in the world

Brackishwaters

ROEvaporation

4

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25 30 35 40 45

Salinity (g/L)

Energy (kWh/m 3)

SWRO with ERI (Y=0.45)

SWRO (Y=0.45)

BWRO (y=0.7)

NF (Y=0.8)

Energy consumption in NF vs ROIntroduction

(F. VINCE, MEDRC Project N° 04-As-005, report 4, Dec. 06)

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Interest of NF vs RO

• Selectivity between ions

• Low applied pressure

• Low energy consumption

• High recovery (> 70%)

• Similar simplicity of the technology

• Very well adapted for brackish water

Introduction

6(M. Pontié, C. K. Diawara, M. Rumeau, Desalination 15 l (2002) 267-274)

32535,5Cl-

104796SO42-

274127I-161540Ca2+

45423Na+

36339K+

IEhyd I (kJ.mol-1)M (g.mol-1)Ion

F- 19 449

SO42-

F-

Cl-

Br -

I -

Rej

e cti

on(%

)

R (SO42-) > R(F-) > R(Cl-) > R(I-)

BW30

NO SELECTIVITY IN RO

Introduction RO membrane selectivity

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NF90

(M. Pontié, C. K. Diawara, M. Rumeau, Desalination 15 l(2002) 267-274)

R(F-) > R(Cl-) > R(I-)

R(F-) >> R(I-) >R(Cl-)

GOOD SELECTIVITY IN NFBETWEEN MONOVALENT SODIUM SALTS

Introduction NF selectivity between monovalents ions

8

65

70

75

80

85

90

95

0 2 4 6 8 10 12 14

Rej

ectio

n (%

)

Transmembrane pressure (bar)

F -

Cl--

I-

NF45

(A. Lhassani, M. Rumeau, D. Benjelloun, M. Pontié,Wat. Research , 35 (13) (2001) 3264-)

Selectivity for a F-/Cl-/I - in a ternary mixture

Introduction

GOOD SELECTIVITY IN NFDEPENDING ON THE TRANS-MEMBRANE PRESSURE

NF selectivity between monovalents ions

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CORRELATION BETWEENSOIL PHOSPHATE CONTENT

Fatick

AND

WATER RESSOURCES RICH IN FLUORIDE IONS

- Fatick, Senegal- Khouribga, Morocco Eocene limit

F- isolinesF- < 0.1mg/L

Introduction

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DENTALFLUOROSIS(F- > 2 mg/L)

10 years of exposure to

4 mg/L F-, in Fatick,

SENEGAL

Regulation in drinking water : < 1.5 mg/L (WHO, 2006)

Introduction

11

OSSEOUSFLUOROSIS(F- > 4 mg/L)

15 years of exposure to 6-10mg/L F-, (Fatick, Senegal)

(TRAVI Y. Geological Sciences, (1993), mémoire 95, ISSN 0302-2684)

Introduction

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Processes of water defluoridationIntroduction

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Experimental Waters Characteristics

*Tan Tan water was doped with NaF at 5, 10 and 15 ppm

< 200-595Na+ (ppm)

< 5001040Hardness (°F)

< 20053500SO42- (ppm)

< 1.53.6 -13.51.1*F- (ppm)

< 50<220NO3- (ppm)

< 2506721200 - 1349Cl- (ppm)

< 100014003300 - 4000TDS (ppm)

6.5-98.227.9pH

< 2516.427T (°C)

WHO water

regulations

(2008)

Senegal

(Fatick,

Thiadiaye)

Tan Tan*Feed water

parameters

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(1) Feed water tank 2.6 m3 , Max feed flow of 3 m3/h ; (2) Pilot units(3) Water cooling unit (T=21°C)

21

3

3

2

1

Experimental Description of the pilot units

Osmonics unit for lab scale experiments

Tan Tan pilot scale experiments

Thiadiaye unit (Senegal, 2010)

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Experimental

Operating conditions

�Flow rate ratio (Y) from 10 to 90%

� Permeate flux : 26 L.m-2.h-1

Membranes tested

�Membranes : 2NF (NF90, NF270) and 1RO (BW30)(supplier : DOW, Filmtec)

� Type : Thin Film Composite in polyamide

� Module : Spiral wound module (4” )

� Membrane area : 137 cm2, 7.6 m2 and

1380 m2 (Thiadiaye)

Structure of a Thin-Film Composite membrane

40 µm

120µm

0.2- 3 µm

Ultrathinbarrier layer

in polyamide

Microporouspolysulfone

Polyester support

Spiral wound module,

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Results and discussion Hydraulic permeability

Effect of the applied pressure on Tan Tan water

flux for the NF90 and BW30 membranes

(pH = 7.9, T = 21°C)

• Lp’ NF > Lp’ RO

• Pc RO ~ Pc NF

Jv=Lp’(∆P – σ∆Π)

Pc

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Jv (L

.h-1.m

-2)

Pressure (bar)

NF90

BW30

Πth. = 3.3 bar Transmembrane pressure (bar)

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TDS rejectionResults and discussion

• NF90 permits to test the highest flow yield (>70%)

with the lowest pressure

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10% 45% 70% 90%

0

2

4

6

8

10

12

14

16

18

20

22

BW30NF90

10%

45%

70%

90%

Feed

Pre

ssu

re (

ba

r)

Energy consumption

Required pressures for

desalination of Tan Tan water for the NF and

LPRO membranes studied at different

recovery rates (Y=70%,

permeate flux=26 L.m-2.hr-1)

nd

Results and discussion

36

100.

.r

PE

η∆=

BW30NF90

•∆P BW30 >> ∆P NF90

• Energy consumption is 2 times lower in NF

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OPERATING CONDITIONS : Membrane NF70 (Filmtec); T=26°C; Transmembrane pressure = 5-6 bar; Flow yield 10 %

Total Salinity (g/L) Hardness (°) pH Sulfate (mg/L) F- (mg/L) Chloride (mg/L)

Raw water 2.0 4.55 8.35 16.2 13.5 655

NF water 0.23 0 7.95 2.9 0.7 85

WHO 0.1< <0.5 - 6.5-9.5 < 250 0.8< < 1.5 < 250

(A. Lhassani, M. Rumeau, D. Benjelloun, M. Pontié, Water Res.35 (13) (2001) 3260–)

R (%) 88 100 - 82 95 87

Fluoride removal 1Results and discussion

KEY RESULTS IN SENEGAL - 1993

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Fatick Gandiaye Thiadiaye Kaolack GossasRobinet Puits1 Puits2 Puits1 Puits2 Robinet Puits Robinet Puits Robinet Puits

Temperature(°C)

16.4 13,2 13,8 10,9 15,9 18,5 17,0 20,0 19,2 20,9 20,5

Turbidity (NTU)

0.94 0,35 0,47 0,35 0,57 0,85 3,88 1,23 0,21 0,45 0,19

Nitrate (mg/L) <2 23,2 339 15,2 59,1 <0,4 129 <0,4 44,3 <0,4 27,1

TOC (mg/L) 7.07 1,12 1,84 4,25 1,74 2,55 1,77 1,40 0,69 1,83 1,10

TIC (mg/L) 65.66 3,94 5,03 14,35 7,34 58,83 39,81 57,92 6,42 55,65 21,2

Fouling index 3pH 8.22 7,03 6,89 7,78 7,63 8,33 8,38 8,25 7,79 8,67 7,97

Conductivity

(µs/cm)2820 211 1351 300 303 1715 772 1980 1198 2100 402

TH (°F) 3.0 3,4 28,4 8,6 6,0 34,0 29,0 2,8 19,2 3,4 12,0

TH Ca2+ (°F) 3.0 3,2 19,2 7,2 4,2 14,4 24,6 2,8 13,6 2,2 9,2

TAC (°F) 39 1,2 0,6 6,2 2,2 33,6 17,0 32,4 2,6 32,8 18,6

Fluoride(mg/L)

3.59 <0,1 0,259 <0,1 <0,1 4,45 0,224 2,6 <0,1 2,530,256

Chloride(mg/L)

672 41,9 213 41,17 42,4 291 68 403 328 444 51,7

Sulfate (mg/L) 53.0 4,6 30 3,9 1,1 122 7,1 66 7,9 60 8,5

UV254(mat.org)

0.238 0,032 0,192 0,726 0,078 0,092 0,218 0,161 0,020 0,066 0,015

UV436(couleur)

0.027 0,003 0,006 0,182 0,009 0,016 0,052 0,035 0,002 0,009 0,001

0

0,5

1

1,5

2

2,5

3

3,5

0 2 4 6 8 10

NF90NF270

Time (h.)

BW30

0

0.5

1

1.5

2

2.5

3

3.5

0 2 4 6 8 10

NF90NF270BW30

F- in the permeate(mg/L)

Operating conditionsP=7 barsFlow yield = 75%

0.8 mg/L

Fluoride removal 2Results and discussion

KEY RESULTS IN SENEGAL - 2004

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y = 0.009x + 0.001

R2 = 0.98

y = 0.025x + 0.038

R2 = 0.98

y = 0.863x + 0.0008

R2 = 0.99

0

0,05

0,1

0,15

0,2

0 0,5 1 1,5 2 2,5

1/Jv(h/L)

Cp(

g/L)

NF90

NF270

BW30

Results and discussion

Permeateconcentration (Cp) of NaCl vs 1/Jv

( membranes NF270, NF90 et OI, C= 0,001 M, T°=25°C,

pH=6.7, Y=5%)

1/Jv (h.L-1)

Cp

(g.L

-1)

BW30 Pure Diffusion

NF90 Diffusion >>> Convection

NF270 Convection >>> Diffusion

Cconv..

Mass tranfer in NF/RO

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Processes of water defluoridationIntroduction

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Variations of fluoride concentration in the permeate for the studied membranes with F- concentrations variations in Tan Tan

water (Y= 70%,Permeate Flux = 26 LMH)

Fluoride removal

(H. DACH, Ph Thesis, MEDRC Project 04As003 )

Results and discussion

0

0,2

0,4

0,6

0,8

1 5 10 15

NF90

BW30

[F- ] feed (mg/L)

[F- ] permeate(mg/L)

KEY RESULTS IN MOROCCO - 2008

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Paramètres Feed WHO after NF

Fluoride (ppm) 4.67 < 1,5

Sodium (ppm) 235 < 200

Chloride (ppm) 280 < 200

Magnesium

(ppm)

51 10 à 50

Calcium (ppm) 56 20 à 270

1.1

150

110

10

10

Feed flow 50 m3/h

Flow yield 70%

Modules

/ membrane area

36 (24+12)

/ 1338 m²

Step 2

Membrane NF 90-400

Thiadiaye Unit (Senegal)Results and discussion

THE FIRST DEFLUORIDATION UNIT IN THE WORLD – 2010

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Less fluorides in drinking water,

better health and dignity

recovering !

Thiadiaye, january 2010

THE FIRST DEFLUORIDATION UNIT IN THE WORLD – 2010

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Conclusion

We have shown for the first time, from lab scale to full scale,the main interest in NF vsRO for drinking water defluoridation

The best membrane is the NF90, due to :- higher water productivity (3 x)- lower specific energy consumption (2 x)- higher selectivity of monovalent ions, i.e. F- vsCl-- partition-diffusion mass transfer predominant

Through this collaboration 2 research teams dedicated to membrane technology started in Fes (Morocco) and Dakar (Senegal) and the first defluoridation unit using NF was builtrecently in Senegal (Thiadiaye).

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Acknowledgements�MEDRC: Projet n° 04-AS-005 (Sultanate of Oman)

� Fes University, LCA (Morocco), A. Lhassani

� VEOLIA WATER, (France), H. BUISSON and H. SUTY

�ONEP (Morocco)

�M. RUMEAU (France) initiator of the research topic

in 1992 (Senegal/France)

� Suez-Environment,CIRSEE, JM Lainé, France

MEDRC Project TEAM, Project n°04-AS-005

Thiadiaye, sept. 2009

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Ra = 13± 5 nm

NF270

Ra = 298± 10 nm

NF90

Results and discussion +NF/RO surface roughness

Ra = 125± 25 nm

BW30