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ECONOMIC AND SOCIAL COMMISSION FOR WESTERN ASIA

WATER DESALINATION TECHNOLOGIES IN THE

ESCWA MEMBER COUNTRIES

United Nations

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Distr.GENERALE/ESCWA/TECH/2001/327 July 2001ORIGINAL: ENGLISH

ECONOMIC AND SOCIAL COMMISSION FOR WESTERN ASIA

WATER DESALINATION TECHNOLOGIES IN THE

ESCWA MEMBER COUNTRIES

United NationsNew York, 2001

01-0675

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Preface

The present publication is one of a series of studies to be carried out by ESCWA to examine andpromote technology development in the field of water, a crucial area for socio-economic development. Astudy to be undertaken during the next biennium will address water treatment technologies, with emphasis onindustrial and municipal wastewater.

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Foreword

Water desalination technologies play a crucial role in socio-economic development in a number ofESCWA member countries. Desalinated water is an essential, and often the sole, source of fresh water inseveral of these countries, and rising living standards and high population growth are likely to renderdesalination a viable option for many other areas of the region as well.

The present study is intended to provide an overview of desalination technologies in the ESCWAregion, which occupies a leading position worldwide in terms of the extent of desalination technologyutilization. Installed and projected desalination capacity in the ESCWA member countries is reviewed with aview to outlining prevailing and expected trends and, hence, possibilities for building on mountingexperience in the selection, management, adaptation and dissemination of appropriate technologies.

The study provides an up-to-date review of the principal classes of desalination technologies, withparticular reference to those suitable for implementation in the ESCWA member countries. Analysis of theprinciples underlying those technologies forms the basis upon which determinations can be made regardingtheir adoption and dissemination. Such analysis is necessary to establish the maturity of underlyingtechnologies and the possibilities they offer enterprises in the member countries for future participation intechnology adaptation, dissemination and development.

Another objective of this study is to review salient economic features of the various desalinationmethods. Criteria for estimating the cost of desalination plants are elaborated, with reference to conditions inthe ESCWA member countries. Prospects for relative changes in the viability of various technologies areoutlined as well.

Considerable development has taken place, particularly during the past decade, in desalinationtechnologies, the materials they use, related economic considerations, and the extent to which they havereceived new inputs from automation and control technologies. This study provides an overview of the mostimportant developments, emphasizing those that offer the ESCWA member countries, and enterprisesoperating therein, possibilities for playing a leading role in technology development.

Special attention is given to desalination technologies that utilize renewable resources, in particularsolar and wind power, for their energy input. The viability of solar energy desalination plants may beconfined to remote area applications at present; however, developments on a number of fronts promise future

cost reductions and consequently greater potential for wider dissemination. Solar and wind desalinationtechnologies are likely to be the methods of choice for providing rural communities with access to freshwater in the many arid parts of the region. Such technologies could free the generally impoverished ruralcommunities, their womenfolk in particular, from the burden and expense of obtaining fresh water fromdistant sources. It is essential that the ESCWA member countries, blessed with rich renewable resources anddeprived of sufficient water supplies, take a leading global position in developing, adapting anddisseminating these and other desalination technologies.

One of the broad objectives of this study is to review the present status of and future trends indesalination technologies at both the global and regional levels. This represents a first step in the efforts ofthe ESCWA secretariat to promote rational technology acquisition and implementation policies andstrategies in this crucial area for socio-economic development in the member countries. In addressing thisimmediate objective, the present study provides a number of conclusions. Many of the conclusions constitute

important messages for the studys target audiences, namely, decision makers and technology managers inboth the public and private sectors, as well as science and technology professionals concerned withdesalination, in general, and in desalination technologies, in particular. Summarized, these conclusions boildown to the fact that desalination technologies offer as many challenges as opportunities for the ESCWA

ESCWA members include Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Palestine (West Bank and Gaza Strip),Qatar, Saudi Arabia, the Syrian Arab Republic, the United Arab Emirates and Yemen.

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member countries but also come with enormous potential end benefits in terms of socio-economicdevelopment and technological capacity building, and even world leadership in this field.

Achieving such objectives will largely depend upon the development and implementation of soundpolicy approaches and novel but well-designed cooperation modalities and partnerships among concernedparties, including public, private and civil society institutions, within the ESCWA member countries.

Mervat TallawyExecutive Secretary of ESCWA

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CONTENTS

Page

Preface ...................................... ........................................... ............................................. ......................... iiiForeword .................................. ........................................... ........................................ .............................. vAbbreviations and explanatory notes ............................................ ........................................... ................. xiv

Introduction ............................................ ........................................... ............................................... ......... 1

Chapter

I. OVERVIEW ...................................... ........................................... ........................................... ...... 1

A. Classification of desalination processes ..................................... ........................................... .. 1B. A global view of desalination capacities and technologies ................................... .................. 4C. Desalination capacities and technologies in the ESCWA member countries................. ......... 7D. Concluding remarks................................ ........................................... ...................................... 25

II. THERMAL DESALINATION PROCESSES .......................................... .................................. 27

A. The multistage flash process............................................... ........................................... .......... 27B. Multiple effect distillation .................................... ........................................ ........................... 36C. Comparison of multistage flash and multiple effect desalination processes ........................... 40D. Vapour compression processes............................. ........................................... ........................ 41E. Concluding remarks............................ ........................................ ........................................... .. 48

III. MEMBRANE SEPARATION PROCESSES .............................................. ............................... 49

A. Microfiltration and ultrafiltration .......................................... ......................................... ......... 50B. Hyperfiltration processes............................................. ........................................ .................... 53C. Electric potential membrane processes................................ ....................................... ............. 63D. Membrane distillation........... ........................................... ....................................... ................. 67E. Membrane materials: microstructure and manufacturing processes........................................ 67F. Membrane fouling and treatment ......................................... .......................................... ......... 70G. Membrane cleaning and storage ...................................... ........................................... ............. 73H. Concluding remarks................................ ........................................... ...................................... 74

IV. DESALINATION ECONOMICS ........................................ ........................................... ............. 75

A. Elements in desalination costing ................................. ........................................ .................... 75B. Capital and operational costs of desalination plants........ ........................................... ............. 76C. Comparison of unit product costs for principal desalination technologies............. ................. 81D. Desalination costs for hybrid and cogeneration facilities .............................................. .......... 85E. Concluding remarks............................ ........................................ ........................................... .. 86

V. RECENT TRENDS AND EXPECTED FUTURE DEVELOPMENTS IN WATER

DESALINATION TECHNOLOGIES ....................................... ........................................... ...... 87

A. Trends in thermal processes ..................................... ........................................... .................... 88B. Trends in membrane processes............... .......................................... ....................................... 98C. An overview of research and development activity in desalination technologies ................... 105D. Desalination research and development activity in the ESCWA member countries............. .. 111E. Concluding remarks............................ ........................................ ........................................... .. 112

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CONTENTS (continued)

Page

VI. RENEWABLE ENERGY DESALINATION TECHNOLOGIES IN THE

ESCWA MEMBER COUNTRIES .......................................... ........................................... ......... 114

A. Renewable energy desalination capacity: a global overview ......................................... ......... 114B. Techno-economic aspects of renewable energy desalination processes................................ .. 118C. Concluding remarks......................... ........................................... ........................................... .. 130

VII. STRATEGIC ISSUES IN DESALINATION TECHNOLOGY CAPACITY BUILDING .... 132

A. Core issues in strategies for promoting desalination technologies in ESCWAmember countries .......................................... ........................................ .................................. 134

B. Concluding remarks......................... ........................................... ........................................... .. 137

LIST OF TABLES

1.1 Installed desalination production capacity and the distribution of various processesin the Gulf countries, the United States and other countries in 1996 and 2000 .............................. 5

1.2 Desalination capacity in the ESCWA region ..................................... ........................................... .. 7

1.3 Installed desalination capacity per capita in the Gulf countries ..................................... ................. 10

1.4 Estimated cost of desalination units in the ESCWA region .................................... ........................ 10

1.5 Average desalination capacity per installed unit and estimated costs per unit and per cubicmetre in the ESCWA region.............................. ............................................... ............................... 12

1.6 Distribution of total installed capacity in the ESCWA region according to principaldesalination technology............................................. ........................................... ........................... 14

1.7 Active desalination projects in Saudi Arabia ........................................ .......................................... 20

1.8 Distribution of desalination capacity in Abu Dhabi, Dubai and Sharjah according to

technology ........................................... ........................................... ............................................... .. 252.1 Plants with capacities of 45,000 m3/day or greater contracted in the ESCWA region

since 1991.............................. ........................................... ............................................... ................ 29

2.2 Operational data on multiple effect distillation plants (without vapour compression) ................... 37

2.3 Comparison of thermal seawater desalination processes ......................................... ....................... 41

3.1 A summary characterization of membrane separation processes.......... ........................................ .. 49

3.2 Pore size determination of ultrafiltration membranes using selected proteins................................ 51

3.3 A comparison of the principal attributes of major ultrafiltration configurations ............................ 52

3.4 Reverse osmosis applications.............................................. ............................................ ................ 56

3.5 Damaging conditions for different types of membranes ...................................... ........................... 58

3.6 Materials for commercial polymer membranes..................................... .......................................... 68

3.7 Sources of membrane fouling ...................................... ........................................... ........................ 703.8 Water treatment chemicals and their functions ..................................... .......................................... 70

4.1 Capital costs for various desalination processes .......................................... ................................... 78

4.2 Energy costs for various desalination processes .......................................... ................................... 79

4.3 Membrane replacement costs ....................................... ........................................ ........................... 79

4.4 Chemical costs for various desalination processes.................................... ...................................... 80

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4.5 Economic factors considered in estimating desalination costs in the Gulf region .......................... 82

4.6 Estimated costs for a multistage flash plant with a 100,000 m3/day capacity................................. 82

4.7 Estimated costs for a multiple effect distillation plant with a 100,000 m3

/day capacity................. 824.8 Estimated costs for a reverse osmosis plant with a 100,000 m3/day capacity................................. 83

5.1 Technical bottlenecks of desalination processes .......................................... ................................... 87

5.2 Multistage flash capacity, number of stages, and performance ratio ............................................. . 88

5.3 Materials used in constructing thermal desalination plants.......................... ................................... 92

5.4 Variations in material characteristics for a brine boiling temperature of 70o C and condensatetemperature of 72o C...... ........................................... ............................................ ........................... 93

5.5 New modules and strategies for concentration polarization and fouling control ............................ 104

5.6 Comparison of model and field data for the single effect mechanical vapour compressionsystem............................ ............................................ ......................................... ............................. 109

5.7 Comparison of model predictions against field data for multiple effect distillation systems

with mechanical vapour compression ........................................ ............................................ ......... 1095.8 Comparison of model predictions against field data for multiple effect distillation systems

with thermal vapour compression ..................................... .......................................... .................... 110

5.9 Comparison of multistage flash and forward- and parallel-feed multiple effectdistillation systems ..................................... ........................................ ........................................... .. 110

5.10 Desalination research conducted in the Gulf countries and Egypt as a proportion ofthe world total ......................................... ........................................... ........................................... .. 112

6.1 Renewable energy desalination plants: total capacity, number of units and estimated costs.......... 114

6.2 Worldwide capacity distribution according to desalination process, power source, feed watertype, area of application and technology used ...................................... .......................................... 115

6.3 Abu Dhabi plant: design features ........................................ ........................................ .................... 121

6.4 Heat balance of the Abu Dhabi solar desalination plant .................................... ............................. 1226.5 Design features of the photovoltaic-reverse osmosis plant in Lampedusa, Italy ............................ 125

6.6 Cost breakdown for the photovoltaic-reverse osmosis plant in Lampedusa, Italy .......................... 126

LIST OF FIGURES

1.1 The desalination concept....................................... ........................................... ............................... 3

1.2 Classification of thermal and membrane desalination processes .............................................. ...... 3

1.3 Distribution of world desalination capacity among top-producing countries in 2000 .................... 6

1.4 Distribution of installed plant capacity in the ESCWA region in 2000 and as expected in 2003 ... 8

1.5 Distribution of estimated expenditure on desalination plants in the ESCWA regionin 2000 and as expected in 2003 ...................................... ....................................... ........................ 11

1.6 Estimated cost of desalination plants contracted in the ESCWA region since 1954 ...................... 11

1.7 Average unit capacity versus average unit cost for desalination systems in the ESCWA region ... 12

1.8 Estimated cost of installed desalination capacity in the ESCWA region .................................. ...... 13

1.9 The cost of installing 1 m3/day of desalination capacity, presented asfive-year averages over the period 1954-2003 ...................................... .......................................... 13

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1.10 The cost of installing 1 m3/day of desalination capacity according todesalination technology, presented as five-year averages over the period 1954-2003 ................... 14

1.11 Distribution of installed plant capacity according to the main desalination process applied in2000 and as expected in 2003 .......................................... ........................................... .................... 15

1.12 Distribution of installed plant capacity according to the main equipment used in 2000and as expected in 2003 ........................................ ........................................... ............................... 15

1.13 Cumulative capacity growth in different desalination technologies installed in theESCWA region............................. ........................................... ............................................... ......... 16

1.14 Distribution of installed plant capacity in the ESCWA member countries according totype of feed water in 2000 and as expected in 2003 ............................................ ........................... 17

1.15 Distribution of installed plant capacity according to feed water type anddesalination technology used in five ESCWA member countries............................... .................... 18

1.16 Distribution of installed desalination plant capacity in the ESCWA membercountries according to application in 2000 and as expected in 2003 ................................... ........... 19

1.17 Desalinated water use for different groupings of ESCWA member countries ............................... 191.18 Cumulative growth in desalination capacity in Saudi Arabia ..................................... .................... 20

1.19 Cumulative growth in desalination capacity in Qatar ...................................... ............................... 21

1.20 Cumulative growth in desalination capacity in Kuwait .......................................... ........................ 22

1.21 Cumulative desalination capacity in the United Arab Emirates since 1970 ................................... 24

1.22 Distribution of desalination capacity in the United Arab Emirates, by emirate...... ........................ 25

2.1 View of a typical multistage flash desalination plant................................ ...................................... 27

2.2 Multistage flash desalination with brine circulation ................................................ ....................... 33

2.3 Schematic representation of the once-through multistage flash process......................................... 34

2.4 Parallel feed multiple effect distillation ...................................... ........................................... ......... 39

2.5 Single effect evaporation with mechanical vapour compression ....................................... ............. 432.6 Parallel feed multiple effect distillation with thermal vapour compression.................................... 45

2.7 Multiple effect distillation with mechanical vapour compression ............................................... ... 46

3.1 Types and effective range of membrane processes ...................................... ................................... 50

3.2 The reverse osmosis process ................................. ........................................... ............................... 55

3.3 Cross-section of a pressure vessel with three membrane elements........................................ ......... 59

3.4 Hollow fine fibre membrane module (assembly and fibre dimensions) ........................................ . 60

3.5 Cutaway view of a spiral wound membrane element..................... ........................................... ...... 61

3.6 Ion transport in electrodialysis .................................. ......................................... ............................. 63

3.7 Movement of ions in the electrodialysis process................................... .......................................... 65

3.8 Coupled transport mechanism for generic metals ........................................ ................................... 67

3.9 Plate and frame filtration................................. ...................................... .......................................... 69

4.1 Cost elements of desalination processes ................................. ........................................... ............. 76

4.2 Unit product cost versus unit capacity for major desalination processes.................................. ...... 84

5.1 Increases in multistage flash desalination unit capacity, 1957-1996 ............................................ .. 89

5.2 Variations in the characteristics of evaporator and plate preheaters for a brine boilingtemperature of 70 C and condensate temperature of 72 C ........................................................... 94

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5.3 Single effect evaporator driven by an adsorption heat pump.................................. ........................ 95

5.4 Schematic of a single effect evaporation system with an absorption heat pump ............................ 95

5.5 Energy recovery in reverse osmosis (using Sulzer pumps)..... ............................................... ......... 1035.6 Areas of desalination research...................................... ........................................... ........................ 106

6.1 National renewable energy desalination capacity in ESCWA member and otherArab countries ..................................... ........................................... ............................................... .. 114

6.2 Capacity distribution of renewable energy desalination plants according todesalination technology............................................. ........................................... ........................... 116

6.3 Capacity distribution of renewable energy desalination plants according tosolar conversion technology......................................... ........................................... ........................ 116

6.4 Capacity distribution of renewable energy desalination plants according to therenewable resource used........................................ ....................................... ................................... 117

6.5 Capacity distribution of renewable energy desalination plants according to feed water ................ 117

6.6 Capacity distribution of renewable energy desalination plants according to areaof application.......... ........................................... ........................................... ................................... 118

6.7 Combining conventional and renewable energy resources for desalination ................................... 118

6.8 Multiple effect solar-powered plant flowsheet.................... .......................................... .................. 119

6.9 Abu Dhabi solar-powered multiple effect desalination plant................................................. ......... 120

6.10 Map of Lampedusa, Italy .......................................... ........................................... ........................... 124

6.11 Block diagram of the 3 m3/hour section of the photovoltaic-reverse osmosis plantin Lampedusa, Italy ........................................ .............................................. ................................... 124

6.12 Modern 1-megawatt wind turbine .................................... ........................................... .................... 127

6.13 General view of the Gran Canaria wind desalination facility ..................................... .................... 128

6.14 Representation of a greenhouse-type flat solar still .................................. ...................................... 129

6.15 A modern greenhouse-type flat solar still ................................... ....................................... ............. 1297.1 Viable combinations of desalination technologies ........................................ .................................. 133

LIST OF FRAMES

1.1 Desalination capacity growth in the ESCWA member countries ...................................... ............. 92.1 Performance parameters for thermal desalination processes.................................................. ......... 282.2 Top brine temperature .......................................... ......................................... .................................. 292.3 Comparison of the multistage flash once-through and brine recirculation systems.............. .......... 352.4 The parallel feed multiple effect distillation process .................................... .................................. 382.5 Main features of the single effect evaporation process with vapour compression.......................... 443.1 Osmosis and reverse osmosis........................................... ............................................... ................ 563.2 Composite reverse osmosis membranes................ ........................................... ............................... 583.3 The impact of oxidants on membranes .......................................... ........................................... ...... 624.1 Direct and indirect capital costs ....................................... ........................................... .................... 774.2 Notes on the economics of reverse osmosis process....................................... ................................ 834.3 Notes on the economics of thermal processes.......... ........................................ ............................... 845.1 Advantages of high-temperature desalination....................................... ....................................... ... 915.2 Improved thermal performance ratio using absorption heat pumps ..................................... ........... 965.3 Proposed novel multistage flash configurations........... ........................................ ........................... 97

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5.4 Pilot facilities for water desalination....... ....................................... ............................................... .. 1015.5 Identifying research and development priorities in desalination............... ..................................... . 1077.1 Environmental impact of desalination technologies ........................................ ............................... 136

ANNEXES

A. Desalination technologies in the Arab countries: tables and figures ....................................... 139B. Desalination plant case studies from Saudi Arabia and the Syrian Arab Republic ................. 144C. Scale formation and scale control methods in multistage flash desalination .......................... 147D. Operational controls for multistage flash plants ......................................... ............................. 149E. Schematic diagrams of thermal desalination processes...... ............................................... ...... 150F. A closer look at some aspects of the multistage flash brine recirculation process .................. 154G. Hyperfiltration performance parameters .......................................... ....................................... 156H. Commonly used modular reverse osmosis schemes........................................ ........................ 157I. Reverse osmosis membranes and configurations ......................................... ........................... 158J. Pretreatment and post-treatment processes for membrane separation technologies................ 160K. Desalination costs ...................................... ........................................... ................................... 166L. Information on desalination trends and research and development activities ......................... 168M. Research and development activities undertaken by the Research and Development

Center in Saudi Arabia ...................................... ........................................... ........................... 172N. Information on desalination processes using renewable energy technologies ........................ 173O. Inorganic salts in seawater............................. ........................................ .................................. 176

ANNEX TABLES

A.1 Desalination capacity in the Arab countries...... ........................................... ................................... 139

A.2 Distribution of installed desalination capacity in the Arab countries according to technology ...... 139

A.3 Progress made by the multistage flash desalination industry in Kuwait ......................................... 139

A.4 Development and features of multistage flash desalination plants in Kuwait........................ ......... 140B.1 Shuaiba Phase II multistage flash cogeneration desalination plant.... ........................................... .. 144

B.2 Reverse osmosis desalination plant for the Oriental Paper Manufacturing company..................... 145

I.1 Examples of industrial reverse osmosis membranes .................................... ................................... 158

J.1 Summary of disinfectant characteristics......................................... ............................................... .. 165

K.1 Unit product costs for a number of conventional and novel processes ........................................... 166

K.2 Estimates of chemical costs and dosing rates................... ........................................... .................... 167

L.1 Variations in the characteristics of evaporator and plate preheaters for a brine boilingtemperature of 70o C and condensate temperature of 72o C ............................................................ 168

L.2 Variations in reverse osmosis unit capacity and total plant capacity at differentlocations around the globe................................. ............................................ .................................. 168

L.3 Examples of multiple effect desalination research conducted in the Gulf countries and Egypt ..... 169

L.4 Examples of multistage flash research conducted in the Gulf countries and Egypt........................ 169

L.5 Examples of reverse osmosis research conducted in the Gulf countries and Egypt........................ 170

L.6 Research and development projects: some examples from the Middle EastDevelopment and Research Center .................................. ........................................... .................... 171

N.1 Capacity distribution according to renewable energy source, feed water and application.............. 173

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N.2 Capacity distribution according to desalination technology ....................................... .................... 174

N.3 Capacity distribution according to renewable energy technology ......................................... ......... 175

O.1 Variations in seawater salinity ......................................... ........................................... .................... 176O.2 Typical seawater composition.......................................... ........................................... .................... 177

O.3 Ions with concentrations exceeding one part per million........................................ ........................ 177

ANNEX FIGURES

A.1 Distribution of plant capacity in the ESCWA member countries according todesalinated water use............................... ....................................... ............................................... .. 142

A.2 Variations in daily per capita water consumption in Kuwait ...................................... .................... 143

E.1 Schematic design of a flash chamber .......................................... ........................................... ......... 150

E.2 Types of flash evaporators ........................................... ........................................... ........................ 150

E.3 Falling/rising film evaporator............................ ............................................ .................................. 151

E.4 Evaporator with natural/forced circulation.............................. ........................................ ................ 151

E.5 Single-stage vapour compression diagram..... ....................................... ........................................ .. 152

E.6 Wiped film rotating disk evaporator (schematic cross-section) ......................................... ............. 152

E.7 Schematic diagram of a recently installed thermal vapour compression desalinationplant (4 x 9000 m3/day capacity)....................... ............................................... ............................... 153

H.1 Common modular configurations for reverse osmosis systems................................................ ...... 157

H.2 Scheme of a multistage membrane column.................. ........................................ ........................... 157

I.1 Cartridge microfilters ..................................... ........................................... ...................................... 159

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ABBREVIATIONS AND EXPLANATORY NOTES

angstromABVC absorption vapour compressionAC alternating currentADVC adsorption vapour compressionAFM atomic force microscopy

Ah ampere-hourBFR biofouling-resistantBOOT build-own-operate-transferCA cellulose acetate (diacetate and triacetate)CAM cellulose acetate membranecm centimetreCPAM composite polyamide membraneCRF capital recovery factorCVC chemical vapour compressionD dayDC direct currentDNA deoxyribonucleic acidED electrodialysisEDR electrodialysis reversalEDTA ethylene diaminetetraacetic acidESR electron spin resonanceFLASH flash evaporatorFM flat membranegal/d gallons per dayGCC Gulf Cooperation Councilg/l grams per litreGOR gain-output ratioHFF hollow fine fibreHFM hollow fibre membraneTHE horizontal tube falling film evaporator

HTME horizontal tube multiple effectHT-MED high-temperature multiple effect distillationIDA International Desalination Associationkg kilogramKISR Kuwait Institute for Scientific ResearchkPa kilopascalkVA kilovolt-amperekW kilowattkWh kilowatt hourLFC low fouling compositeLT-MED low-temperature multiple effect distillationm2 square metrem3 cubic metre

MCM million cubic metresMED multiple effect distillationMED-ABS multiple effect distillation with absorption heat pumpMES multiple effect stack-typeMF microfiltrationMJ/m2 megajoules per square metremm millimetreMSF multistage flash

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ABBREVIATIONS AND EXPLANATORY NOTES (continued)

MSF-BR multistage flash with brine recirculationMSF-M brine mixing multistage flashMSF-OT multistage flash once-throughMTU membrane type unknownMVC mechanical vapour compression

MW megawattMWCO molecular weight cut-offNF nanofiltrationnm nanometreNMWCO nominal molecular weight cut-offNTU nephelometric turbidity unitPAN-PVC polyacrylonitrile/polyvinyl chloride copolymerppm parts per millionPR performance ratioPTFE polytetrafluoroethylenePV photovoltaicR and D research and developmentRO reverse osmosisrpm revolutions per minuteRSW reversible spiral woundSDAWES seawater desalination plants connected to an autonomous wind energy systemSDI silt density indexSEE single effect evaporationSEE-VC single effect evaporation with vapour compressionSWM spiral wound membraneTBT top brine temperatureTDS total dissolved solidsTVC thermal vapour compressionUF ultrafiltrationUPS uninterruptible power supply

UV ultravioletV voltVC vapour compressionVFF vortex flow filtrationVTE vertical tube falling film evaporator (or evaporation)VVC vacuum vapour compressionWFRD wiped film rotating diskWHO World Health OrganizationW/m2 watts per square metreWp peak watts

The following symbols have been used in the tables throughout the publication:

Two dots (..) indicate that data are not available or are not separately reported.

A dash () indicates that the amount is nil or negligible.

A hyphen (-) indicates that the item is not applicable.

Parentheses ( ) indicate a deficit or decrease, except as otherwise stated.

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ABBREVIATIONS AND EXPLANATORY NOTES (continued)

A slash (/) indicates a financial or crop year (for example, 1981/82).

Use of a hyphen (-) between dates representing years (for example, 1981-1983) signifies the fullperiod involved, including the beginning and end years.

Details and percentages do not necessarily add up to totals because of rounding.

In both the text and tables of the publication, references to dollars ($) indicate United States dollars,unless otherwise stated.

Bibliographical and other references have, wherever possible, been verified.

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INTRODUCTION

Fresh water is rapidly becoming a scarce resource in many countries around the world. Moderndesalination technologies, applied to seawater and brackish water, offer effective alternatives in a variety ofcircumstances. The ESCWA member countries, situated as they are on the most arid part of the globe andcharacterized by some of the worlds highest population growth rates, would benefit greatly from theadaptation, further development and wider dissemination of desalination technologies.

Large-scale thermal desalination technologies have been in use since the 1950s. The largerdesalination plants have provided fresh water supplies for drinking, municipal use and agriculturaldevelopment, particularly in the Gulf States. In the past, high capital costs and heavy energy consumptiongenerally translated into excessive desalinated water costs. However, advances in technology have helped todrastically reduce capital and running costs as well as energy requirements, rendering desalination moreviable an option than ever before.

New high-performance processes, predominantly based on high-performance membrane technologiessuch as nanofiltration (NF) and reverse osmosis (RO), were developed and first applied by the industry in the1970s and 1980s, with the promise of further cost reductions and process simplification. New developmentswill only enhance the potential embodied in desalination technologies for the ESCWA member countries.

This study is essentially aimed at outlining trends in modern desalination technologies andhighlighting the options offered by recent technological advances. The study analyses available technologies,proposed design improvements and market potential in the near future. Through case studies, some of theirmore salient features are examined. Energy demands for both current processes and the newer innovationsare considered. The economics of existing and proposed solutions are also addressed, with special referenceto the ESCWA member countries, in particular the Gulf States, which collectively constitute one of the moreprolific groups of desalination technology users, accounting for over 50 per cent of the worlds capacity.

The first chapter of the study provides a brief overview of the desalination industry throughout theworld before focusing, in a little more detail, on desalination technologies used by the ESCWA members andother Arab countries. Existing capacity is briefly analysed, and issues relating to projected capacity increasesare reviewed from various perspectives, including geographical distribution, technology options, feed watertypes and application areas. To conclude, the role of desalination technologies as a reliable remedy to watershortages is highlighted.

The second chapter concentrates on thermal desalination systems. Thermal technologies constitute themainstay of large-scale desalination in the ESCWA member countries and enjoy a relatively importantposition worldwide. The multistage flash (MSF) distillation process receives extensive coverage, since itaccounts for more than 93 per cent of total production capacity for thermal processes; in order of decreasingimportance, vapour compression (VC) and multiple effect distillation (MED) technologies account for theremainder. Performance parameters, dominant designs and principal variations on those designs areconsidered, as are some of the more important problems faced by users. Some attention is devoted to scaling,with an overview of methods used in dealing with its deleterious effects.

Membrane desalination processes are highlighted in the third chapter of the study. The distinctadvantages associated with these technologies and the steady infusion of innovative inputs are behind theincreased attention in this area. Particular emphasis is devoted to RO technology, presently MSF

desalinations main competitor. This chapter reviews the performance parameters, materials andconfigurations used for membrane desalination systems. Desalination techniques associated withelectrodialysis (ED) are also examined.

The fourth chapter is devoted to desalination economics. A variety of issues pertaining to unit productcost reduction are addressed, with particular attention given to energy consumption, choice of materials andequipment used. In essence, reduced energy requirements, the recent incorporation of energy recoverysystems, the introduction of novel membrane materials and the development of more efficient configurations

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are behind the drastic decrease in desalination costs for membrane operations during the past several years.Recent contracts and offers for new MSF and RO plants in the ESCWA member countries reflectconsiderable reductions in unit product costs.

Chapter V presents some of the more important technological innovations that have been proposed orapplied by the desalination industry in recent years. Reliable combinations of desalination technologies andhybrid schemes actually under investigation are reviewed, and the recent progress made in membrane

desalination processes is highlighted, with an indication of the opportunities deriving from the integration ofdifferent membrane operations to reduce operational costs. Dominant trends and expected outcomes ofresearch and development (R and D) relating to desalination technologies are also considered in this chapter.

The sixth chapter is dedicated to renewable energy inputs in desalination. The use of photovoltaic(PV) and wind energy technologies, in combination with RO technology, show particular promise. Thepotential for greater incorporation of renewable energy inputs in desalination in the ESCWA membercountries is beyond question, given the abundance of solar resources and the numerous possibilities forutilizing wind resources in the region. Enhanced activity in this area would bring considerable medium- andlong-range reductions in unit product costs, and the use of renewable energy or a combination ofconventional and renewable energy inputs would allow a much wider dissemination of the industrysactivities in remote areas, where the provision of sufficient quantities of fresh water is essential for continueddevelopment.

A number of somewhat marginal technologies including desalination by freezing, solar stills andhumidification-dehumidification techniques are also considered in chapter VI. While such technologies donot presently account for a large proportion of total production capacity, they may represent viable options incertain special situations. Innovations in materials and control modalities could well bring some of thesemethods into more widespread use in the future.

The seventh and final chapter of the study includes a summary of the conclusions reached. The issuesaddressed in chapters I-VI represent crucial elements for the formulation of strategies and future action plansaimed at facilitating the acquisition of capacity for the adaptation and development of desalinationtechnologies in the ESCWA member countries. The principal considerations in devising such strategies andaction plans are outlined in this chapter.

Information illustrating the particularities of desalination efforts in various ESCWA member countries

is presented in different parts of the study. Details relating to specific desalination plants are included inchapter VI and annex B. The case studies underline current practices in technology implementation andhighlight prevalent design trends; they also offer lessons that can contribute to the development of futurestrategies aimed at promoting water desalination technologies in the ESCWA member countries. Theannexes include numerous tables and charts that support and supplement the material presented in the mainpart of the study.

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I. OVERVIEW

A. CLASSIFICATION OF DESALINATION PROCESSES

Desalination processes essentially entail the separation of nearly salt-free water from sea or brackishwater, with the salts originally in the feed water are concentrated in a reject brine stream. Both thermal andmembrane separation methods are in common use. Figure 1.1 summarizes the main concepts underlying the

desalination process, while figure 1.2 provides an overview of the main desalination process categories andtheir relationships to one another.

Figure 1.1. The desalination concept

Form of EnergyThermal

Mechanical

Electric Potential

Rejected Brine

Product

Fresh WaterFeed

Sea or

Brackish

Water

Separation Unit

Thermal

or

Membrane

Source: H. El-Dessouky and H. Ettouny, Study on water desalination technologies, prepared for ESCWA in January 2001.

Figure 1.2. Classification of thermal and membrane desalination processes


Phase-change separation methods fall into two main categories. In the first, water is evaporated andthe resulting vapour condensed; an alternative approach involves freezing the water, followed by theseparation and melting of ice crystals. The first process is the most common in commercial desalination and

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is coupled, in most cases, with power generation in dual-purpose plants. Only a few facilities using thefreezing method are known to be in operation.

Evaporation may be carried out by bringing water in contact with a heat transfer surface in what isreferred to as a boiling process. Alternatively, bulk feed water can be made to produce vapour through whatis termed a flashing process. Evaporation processes include MSF, MED, single effect evaporation withvapour compression (SEE-VC), humidification-dehumidification, and a number of methods based on the use

of solar energy.1

Vapour compression is combined with single or multiple effect desalination processes to improvethermal efficiency. In the VC process, low temperature vapour formed in the same effect or the precedingevaporation effect is compressed and used to initiate the evaporation process in the first or the sameevaporation effect. The VC process incorporates component devices that include mechanical compressors,steam-jet ejectors, TVC components, adsorption/desorption beds, and absorption/desorption columns.2Variants of the single effect VC process include mechanical vapour compression (MVC), thermal vapourcompression (TVC), absorption vapour compression (ABVC), adsorption vapour compression (ADVC), andchemical vapour compression (CVC).

Membrane desalination processes include RO and ED. In the RO process, high pressure forces freshwater to permeate through a semi-permeable membrane, leaving behind a highly concentrated brine solution.While pressure is the driving force in the RO process, electrical energy activates ED operation, causingelectrically charged salt ions to move through selective ion exchange membranes, leaving behind low salinityproduct water. In both processes a highly concentrated brine stream is formed on the other side of themembrane. As indicated below, the RO process is enjoying increased popularity, while the ED process haslimited industrial applications.

Extensive work was done in the 1950s and 1960s to develop freezing as a means of water desalination.During the freezing process, dissolved salts are naturally excluded from ice crystals. Before the entire massof water has frozen, the mixture is usually rinsed to remove the salts in the remaining salt-laden wateradhering to the ice crystals. The cleaned ice is then melted to produce fresh water.

In principle, freezing has some advantages over distillation, the predominant desalination process atthe time the freezing process was developed. These advantages include lower theoretical energyrequirements and limited corrosion, scaling and salt precipitation in plant components. One of the main

disadvantages is that the process involves dealing with ice and water mixtures that are mechanically ratherdifficult to handle.

More detailed descriptions of the above-mentioned processes are provided in chapters II and III.

B. A GLOBAL VIEW OF DESALINATION CAPACITIES AND TECHNOLOGIES

By the beginning of this century, there were more than 13,500 desalination units in operationworldwide with a combined actual production capacity of around 26 million cubic metres per day (MCM/d),distributed among more than 120 countries. Current production capacity is almost twice that of a decade ago.The estimated volume of the global desalination market is expected to exceed $70 billion during the next 20years. Approximately $10 billion has been earmarked for the installation of new desalination unitsthroughout the world within the next five years, which will increase production by around 5.3 MCM/d. 3

1 See chapter VI of the present study.

2 H.M. Ettouney, H.T. El-Dessouky and I. Alatiqi,Understand thermal desalination, Chemical Engineering Progress, vol.95 (1999), pp. 43-54.

3 P. Wolf, Declining costs spur desalination market growth, Water & Wastewater International(June 2000), p. 4.

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Table 1.14 shows the market shares of major producers of desalinated water, together the distributionof production capacities among the more important technologies (including MSF, MED, MVC, RO and ED)for 1996 and 2000.

TABLE 1.1.INSTALLED DESALINATION PRODUCTION CAPACITY AND THE DISTRIBUTION OF VARIOUSPROCESSES IN THE GULF COUNTRIES, THE UNITED STATES AND OTHER COUNTRIES

IN 1996 AND 2000

Country YearTotal capacity(1,000 m3/d)

Percentagerelative tototal worldproduction MSF (%) MED (%) MVC (%) RO (%) ED (%)

1996 5 253 23.6 65.6 0.3 1.2 31.0 1.9Saudi Arabia2000 5 429 21.0 64.2 0.3 1.4 32.3 1.81996 3 093 15.6 1.7 1.8 4.5 78.0 11.4United States2000 4 328 16.7 1.3 4.4 6.4 74.4 13.51996 2 165 9.8 89.8 0.4 3.0 6.5 0.2United Arab Emirates2000 2 891 11.2 86.7 7.7 0.03 5.5 0.11996 1 538 6.8 95.2 0.7 3.4 0.3Kuwait2000 1 615 6.2 96.4 0.1 3.3 0.21996 745 3.8 4.7 2.0 86.4 6.8Japan2000 945 3.7 3.9 2.3 84.3 7.41996 683 3.4 67.7 0.9 1.8 19.6 9.8Libyan Arab Jamahiriya2000 701 2.7 65.7 10.7 15.9 7.71996 567 2.8 94.4 0.6 3.3 Qatar2000 573 2.2 94.3 3.9 1.8 1996 530 2.6 10.6 0.9 8.7 68.9 10.9Spain2000 1 234 4.8 4.5 3.5 2.8 84.2 5.01996 519 2.6 43.2 1.9 15.1 20.4 19.2Italy2000 581 2.2 43.6 12.3 6.4 21.5 16.21996 309 1.5 52.0 1.5 41.7 4.5Bahrain2000 473 1.8 62.7 9.7 26.9 0.71996 193 1.0 84.1 2.2 11.7 Oman2000 378 1.2 87.3 1.1 3.7 7.6 0.21996 15 595 76.8 54.8 0.9 2.7 36.1 4.8Subtotal for top

producers 2000 19 148 73.9 50.0 3.8 2.3 38.8 5.11996 10 025 49.4 77.0 0.4 1.5 19.7 1.2Subtotal for Gulf States

(ESCWA region) 2000 11 359 43.8 76.7 2.8 0.8 18.8 0.91996 20 300World total2000 25 909


Note: MSF = multistage flash; MED = multiple effect distillation; MVC = mechanical vapour compression; RO = reverseosmosis; ED = electrodialysis.

The paragraphs that follow will further explain some of the more important trends in capacity growthand technology acquisition.

In 1996, the Gulf States of the ESCWA region and the United States of America accounted for around65 per cent of the worlds production of desalinated water. This proportion dropped to 60 per cent in the year2000 owing to a rise in production capacities in countries such as Italy, Japan, Spain and the Republic of

Korea. Spain actually doubled its production capacity during the period 1996-2000. The Gulf CooperationCouncil (GCC) member countries presently account for around 44 per cent of the total world production ofdesalinated water. Figure 1.3 shows the distribution of world desalination capacity among top-producingcountries in the year 2000.

4 Slight differences between data in table 1.1 and subsequent tables in this chapter derive from the use of different sources.

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Figure 1.3. Distribution of world desalination capacity among top-producing countries in 2000

Bahrain

2%

Italy

2%

Spain

5%

Oman

1%

Libya

3%

Qatar

2% Japan

4%

Kuwait

6%

UAE

11%

USA17%

Saudi Arabia

21%

Other countries

26%

Source: Based on data provided by H. El-Dessouky and H. Ettouny in their Study on water desalination technologies,

prepared for ESCWA in January 2001.

The majority of MSF plants in operation use brine circulation. Most MED plants appear to operate inthe parallel feed mode, at low temperature, with or without TVC. Installed MVC plants are found with single

or multiple effect processes.

In 1996, the world market share for MSF in sea and brackish water desalination totalled more than 54per cent, while the RO process accounted for slightly more than 36 per cent of installed capacity. By 2000,however, the respective shares had drawn much closer, to 42.4 and 41.1 per cent, respectively.

A different picture emerges for seawater desalination alone; in 2000, MSF accounted for 70 per centand RO for only around 18 per cent of installed capacity.

In 2000, the production capacity of units based on MSF technology accounted for around 93 per centof total thermal desalination capacity, and RO unit capacity represented more than 88 per cent of the capacityof all facilities utilizing membrane processes.

The world market share of MED processes rose considerably between 1996 and 2000. Many of the topproducers of desalinated water recorded increases from initial shares of between 0 and 2 per cent to values ofaround 10 per cent and even higher.

Desalination in the GCC States is dominated by MSF, with national shares ranging between 63 and 97per cent. The MSF process has proved suitable for the relatively harsh conditions pertaining in thesecountries. Feed seawater temperatures in the Gulf vary widely, ranging from 12o to 35o C between the winterand summer seasons, and air temperatures can reach levels close to 50 o C during the summer. Another factorto be taken into account is the salinity of Gulf seawater, which ranges between 42,000 and 64,000 parts permillion (ppm).5 These considerations, along with the nearly 50 years of accumulated technical experience inMSF development, render this process a particularly popular option. The more widespread use of ROtechnology in Japan, Spain and the United States has to do with the fact that RO plants operate on lowsalinity sources (mostly brackish or river water).

5 See annex O, relating to inorganic salts in seawater.

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C. DESALINATION CAPACITIES AND TECHNOLOGIES IN THE ESCWA MEMBER COUNTRIES

1. Desalination capacity and number of units

Table 1.2 provides an overall view of desalination capacity and the number of units installed,contracted and planned in the ESCWA region.6 The total capacity for installed and contracted desalinationplants is estimated at around 11.5 MCM/d, which represents 44 per cent of the world total of around 26

MCM/d.

TABLE 1.2.DESALINATION CAPACITY IN THE ESCWA REGION

Source: K. Wangnick, 2000 IDA worldwide desalting plants inventory: report No. 16 (Wangnick Consulting, May 2000).

a/ Including plants installed before 31 December 2000 (operational).b/ Including plants contracted before 31 December 2000 but still under construction (not operational).c/ Including plants to be contracted during the period 2000-2003.

Contracted desalination capacity amounts to 4.5 per cent of total installed capacity; the contractedunits are expected to come on stream during 2001. The capacity of plants planned for the period 2000-2003

amounts to around 3.4 MCM/d, or 30 per cent of installed and contracted capacity in the ESCWA membercountries.

6 K. Wangnick, 2000 IDA worldwide desalting plants inventory: report No. 16 (Wangnick Consulting, May 2000). Thisreport provides information on land-based desalination plants rated at more than 500 m3/d per unit and contracted, delivered or underconstruction as of 31 December 1999. Planned projects listed in this report include those that are part of long-term developmentschemes and projects that have been postponed for financial or other reasons.

ESCWA memberInstalled capacitya/

(1,000 m3/d)

Contractedcapacityb/

(1,000 m3/d)Planned capacityc/

(1,000 m3/d)Total capacity(1,000 m3/d)

Ratio of total toinstalled capacity

(a) CapacitySaudi Arabia 5 139 12 5 151 1.0United Arab Emirates 2 521 373 2 185 5 080 2.0Kuwait 1 527 109 359 1 995 1.3Qatar 573 242 815 1.4Bahrain 473 284 758 1.6Iraq 324 324 1.0Oman 218 282 500 2.3

Egypt 170 9 179 1.1Yemen 67 67 1.0Lebanon 17 17 1.0Jordan 9 82 91 10.1Syrian Arab Republic 5 5 1.0Palestine 1 1 1.0

Total 11 046 494 3 444 14 984 1.4(b) Number of desalination units

Saudi Arabia 882 3 885 1.0United Arab Emirates 227 10 55 292 1.3Kuwait 129 4 22 155 1.2Qatar 60 10 70 1.2Bahrain 65 9 74 1.1Iraq 171 171 1.0Oman 29 11 40 1.4

Egypt 118 3 121 1.0Yemen 19 19 1.0Lebanon 13 13 1.0Jordan 12 4 16 1.3Syrian Arab Republic 6 6 1.0Palestine 1 1 1.0

Total 1 732 17 114 1 863 1.1

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Changes in the ratio of total capacity (installed, contracted and planned) to installed capacity varyfrom one country to another. During the period 2000-2003, Jordan intends to increase its capacity tenfold,while Oman and the United Arab Emirates plan to double their capacities. The region as a whole shouldwitness an increase of around 40 per cent, according to a report issued by the International DesalinationAssociation (IDA). This figure is probably an underestimate, since planned capacity in Saudi Arabia, a majorproducer, is not included in the IDA analysis. A report inMiddle East Economic Digest7 lists 14 desalinationprojects in Saudi Arabia that are expected to become operational during the period 2001-2003. The capacity

of these projects amounts to 1.7 MCM.8

As shown in table 1.2, Saudi Arabia and the United Arab Emirates will come close to one another atthe top of the list in terms of total capacity once all contracted and planned units are operational. The factthat the number of plants contracted in Saudi Arabia presently exceeds the number contracted in the UnitedArab Emirates by a factor of four is indicative of the wider geographical dissemination and considerablysmaller average plant capacity in Saudi Arabia.

Table 1.2 also shows that 95 per cent of the regions installed, contracted and planned capacity isconcentrated in the GCC countries. Among the non-GCC members, Egypt, Iraq and Jordan are set to becomethe top three users of desalination technology.

Figure 1.4 provides a graphical illustration of information presented in the table, indicating the limitedpenetration of desalination production in some areas of the region.

Figure 1.4. Distribution of installed plant capacity in the ESCWA region

in 2000 and as expected in 2003

Yemen

1% (67)

Lebanon

0.2% (17)

Egypt

2% (170)Iraq

3% (324) Jordan

0.1% (9)

Syria

0.05% (5)

Palestine

0.01% (1)

Oman

2% (218)

Bahrain

4% (473)

Qatar

5% (573)

Kuwait14% (1,527)

UA E

23% (2,521)

Saudi

Arabia

46% (5,139)

Palestine

0.01% (1)

Saudi

Arabia

34.4%

(5,151)

Jordan

0.6% (91)Iraq

2.2% (324)

Yemen

0.4% (67)

Oman

3.3% (500)

Bahrain

5.1% (758)

UA E

33.9%

(5,080)

Qatar

5.4% (815)

Kuwait13.3%

(1,995)

Egypt

1.2% (179)Lebanon

0.1% (17)

Syria

0.04% (5)

(a) 2000 (b) 2003


Note: Figures in brackets represent absolute capacity values in thousands of cubic metres per day.

Frame 1.1 provides an overview of desalination capacity growth in the ESCWA member countries.

7 Middle East Economic Digest, special report on water, vol. 44, No. 4 (28 January 2000), p. 12.

8 The largest of these is the MSF Jubail II extension project, with a capacity of 727,300 m3/d, to be completed in 2002.

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Frame 1.1. Desalination capacity growth in the ESCWA member countries

Figure (a) presents a view of cumulative desalination capacity growth during the period 1954-2003, indicatingsomewhat gradual increases in the 1970s and early 1980s, and more abrupt increases in the early and late 1990s. Inflection

points, or periods that witnessed small additions to existing capacity, are observed in the late 1980s and much of the 1990s.

Figure (a). Cumulative plant capacity in the ESCWA region since 1954

(Cubic metres per day)

-

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

16,000,000

1954

1958

1962

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003


Absolute yearly growth in total plant capacity in the ESCWA region reached a peak of around 2.5 MCM/d during2000, as shown in figure (b).

Figure (b). Absolute yearly growth in total plant capacity in the ESCWA region

(Thousands of cubic metres per day)

-

500

1,000

1,500

2,000

2,500

1954

1958

1962

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

Thousands m3/d


Table A.1 in annex A provides an indication of desalination technology dissemination in Arabcountries not members of ESCWA.9 These countries have installed a total of around 1 MCM/d ofdesalination capacity for around $1.8 billion. Within this group, the Libyan Arab Jamahiriya accounts for 71

per cent of the total; Algeria comes in a distant second, with 19 per cent, followed by Tunisia, with 7 percent.

Among the GCC countries, the United Arab Emirates appears to have the highest installeddesalination capacity per 1,000 inhabitants, followed by Qatar and Kuwait (see table 1.3). Variations in per

9 Including Algeria, Eritrea, the Libyan Arab Jamahiriya, Mauritania, Morocco, Sudan and Tunisia.

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Figure 1.5. Distribution of estimated expenditure on desalination plants in the ESCWA region

in 2000 and as expected in 2003

UAE

25% (4,141)

Lebanon

0.2% (40)

Yemen

1% (119)

Egypt

2% (327)

Oman

2% (388)Iraq

2% (274)

Jordan

0.1% (16)

Syria

0.04% (7)

Palestine

0.004% (1)

Bahrain4% (652)

Qatar

6% (981)

Kuwait

13% (2,168) Saudi

Arabia

45% (7,471)

Palestine

0.003%

(1)

Syria0.03% (7)

Lebanon

0.2% (40)

Egypt

1.6%

(349)

Kuwait

13.1%

(2,890)

Qatar

6.0%

(1,315)

UA E

34.2%

(7,512)

Bahrai

5.1%

(1,124)

Oman

3.5% (777)

Yemen

0.5% (119)

Iraq

1.2%

(274)

Jordan

0.4%

(86)

Saudi

Arabia

34.1%

(7,499)

(a) 2000 (b) 2003


Note: Figures in brackets represent reported installation costs and contract values in millions of US dollars.

Figure 1.6. Estimated cost of desalination plants contracted in the ESCWA region since 1954

0

500

1000

1500

2000

2500

3000

3500

1954

1958

1962

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

US$ mill ion

0

5

10

15

20

25

30

35

US$ per barrel ;

Base: 1973=100Estimated cost of desalinat ion plants Nominal oil price

Sources: K. Wangnick, 2000 IDA worldwide desalting plants inventory: report No. 16 (Wangnick Consulting, May 2000);Organization of Petroleum Exporting Countries, Annual Statistical Bulletin, 1998 (Vienna, OPEC, 1999); and ESCWA oil pricestatistics.

Note: Oil prices are as follows: from 1970 to 1981, the Arab Light official price; from 1982 to 1999, the OPEC spot referencebasket price; the value for 2000 is an ESCWA estimate; and the value for 2001 is an ESCWA forecast.

Table 1.5 provides information on desalination capacity per installed desalination unit, the estimated

cost of each desalination unit, and the estimated cost per cubic metre of installed capacity in the variousESCWA member countries. The table indicates that all the GCC countries, with the exception of SaudiArabia, have installed high-capacity units averaging between 10,000 and 17,000 m3/d, while most of theESCWA members with more diversified economies have opted for smaller units. As shown in figure 1.7,unit capacities are commensurate with the estimated cost per unit, which ranges between $1.1 million in theSyrian Arab Republic and $25.7 million in the United Arab Emirates.

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TABLE 1.5. AVERAGE DESALINATION CAPACITY PER INSTALLED UNIT AND ESTIMATED COSTSPER UNIT AND PER CUBIC METRE IN THE ESCWA REGION

ESCWA memberAverage capacity per unit

(m3/d/unit)

Estimated costper unit

(US$ million/unit)Estimated cost per m3 of

installed capacity (US$/m3)Saudi Arabia 5 821 8.5 1 456United Arab Emirates 17 396 25.7 1 479

Kuwait 12 869 18.6 1 449Qatar 11 643 18.8 1 614Bahrain 10 240 15.2 1 483Oman 12 504 19.4 1 552Iraq 1 898 1.6 845Egypt 1 482 2.9 1 943Jordan 5 691 5.4 941Yemen 3 516 6.3 1 779Lebanon 1 314 3.1 2 349Syrian Arab Republic 915 1.1 1 188Palestine 1 300 0.6 462

Average 8 043 11.8 1 468


Figure 1.7. Average unit capacity versus average unit cost for desalinationsystems in the ESCWA region

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 5,000 10,000 15,000 20,000

Capacity per unit (m3/d/unit)

Estimated cost

per unit

(US$

million/unit)

SYIR

LB

EG

YE

JO

SA

BH

QAOM

KW

UAE

PA T


Slight departures from the straight line produced by plotting the estimated cost per unit against thecapacity per unit are observed. Unit costs in Egypt, Lebanon, Qatar and Yemen appear to be slightly abovethe line, indicating marginally higher than average unit costs, while units in Iraq, Jordan and the Syrian ArabRepublic appear to be associated with slightly lower than average costs.

Average cost per cubic metre of installed capacity in the ESCWA region ranges between $845 in Iraqand $2,349 in Lebanon. The corresponding figure is $1,500/m3 for the Gulf countries as a group (see figure

1.8).

Figure 1.9 illustrates the changes in the cost of installing 1 m 3 of desalination capacity during thesecond half of the twentieth century, indicating a gradual decline from $2,000-$2,500 in the latter part of the1950s to $1,500 today.

BH: BahrainEG: EgyptIR: IraqJO: JordanKW: KuwaitLB: LebanonOM: OmanPAT: PalestineQA: QatarSA: Saudi ArabiaSY: Syrian Arab Republic

UAE: United Arab EmiratesYE: Yemen

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Figure 1.8. Estimated cost of installed desalination capacity in the ESCWA region(US dollars per cubic metre per day)

0

500

1,000

1,500

2,000

2,500

SaudiArabia

UAE

Kuwait

Qatar

Bahrain

Oman

Iraq

Egypt

Jordan

Yemen

Lebanon

Syria

Palestine


Figure 1.9. The cost of installing 1 m

3

/day of desalination capacity,presented as five-year averages over the period 1954-2003

-

500

1,000

1,500

2,000

2,500

3,000

54-59

59-64

64-69

69-74

74-79

79-84

84-89

89-94

94-99

99-03


Figure 1.10 displays the variation over time in the cost of installing 1 m3 of desalination capacity fordifferent technologies. Within this framework, MSF and VC unit costs generally declined during the 1990s,while RO unit costs increased. Chapter IV of this study provides additional information on desalinationcosting.

3. Desalination technology capacities and growth patterns

Table 1.6 and figure 1.11 show the distribution of total desalination capacity (installed, contracted andplanned) in the ESCWA member countries across process technologies. MSF desalination accounts for thelargest share of the market, representing around 74 per cent of total capacity; RO and VC technologiesoccupy and distant second and third place, with respective shares of approximately 20 and 3 per cent.

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Figure 1.10. The cost of installing 1 m3/day of desalination capacity according to desalination

technology, presented as five-year averages over the period 1954-2003

-

500

1,000

1,500

2,000

2,500

3,000

54-59

59-64

64-69

69-74

74-79

79-84

84-89

89-94

94-99

99-03

VC MSF RO

Source: K. Wangnick, 2000 IDA worldwide desalting plants inventory: report No. 16 (Wangnick Consulting, May 2000).Note: VC = vapour compression; MSF = multistage flash; RO = reverse osmosis.

MSF is still the most widely used process in the Arab countries not members of ESCWA (see tableA.2 in annex A), accounting for around 54 per cent of installed capacity, followed by RO (26 per cent) andVC (11 per cent).

TABLE 1.6.DISTRIBUTION OF TOTAL INSTALLED CAPACITY IN THE ESCWA REGION ACCORDING TOPRINCIPAL DESALINATION TECHNOLOGY

(Thousands of cubic metres per day)

Technology Installed capacitya/ Contracted capacityb/ Planned capacityc/ Total capacityMultistage flash 8 213 317 2 623 11 153Reverse osmosis 2 250 109 9 2 368Vapour compression 313 68 235 616

Nanofiltration 250 250Electrodialysis 181 181Multiple effect distillation 85 85Other/unspecified processes 5 327 331

Total 11 046 494 3 444 14 984


a/ Including plants installed before 31 December 2000 (operational).b/ Including plants contracted before 31 December 2000 but still under construction (not operational).c/ Including plants to be contracted during the period 2000-2003.

Figure 1.12 shows the distribution of installed plant capacity according to the main equipment used.Flash evaporators, used in the MSF process, represent 75 per cent of the total. Horizontal tube falling filmevaporators (HTEs), used mainly in VC operations but also in MED, account for a 3 per cent share. ROprocesses use, almost equally, hollow fibre membrane (HFM) and spiral wound membrane (SWM)configurations, which make up 9 and 8 per cent of total plant capacity, respectively.

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Figure 1.11. Distribution of installed plant capacity according to the main desalination

process applied in 2000 and as expected in 2003

MSF

74% (8,213)

ED

2% (181)

MED

1% (85)

OTHER

0.04% (5)VC

3% (313)

RO

20% (2,250)

MSF

74%

(11,153)

ED

1% (181)

MED

1% (85)NF

2% (250) OTHER

2% (331)VC

4% (616)

RO

16% (2,366)

(a) 2000 (b) 2003


Notes: Figures in brackets represent capacity values in thousands of cubic metres per day. Key to abbreviations: MSF =multistage flash; RO = reverse osmosis; VC = vapour compression (mechanical and thermal); NF = nanofiltration; ED =

electrodialysis; MED = multiple effect distillation (not vapour compression); HYBRID = hybrid process; OTHER = other orunspecified processes.

Figure 1.12. Distribution of installed plant capacity according to the main equipment

used in 2000 and as expected in 2003

FLASH

75% (8,213)

VTE

1% (92)

FM

2% (192)

OTHER

0.1% (12)

MTU

2% (274)HTE

3% (299)

HFM

9% (1,038)

SWM

8% (926)

FLASH

73% (11,062)

FM

1% (192)

OTHER

3% (439)

VTE

1% (102)

MT U

3% (383)HT E

4% (593)HFM

7% (1,038)

SWM

8% (1,175)

(a) 2000 (b) 2003


Notes: Figures in brackets represent capacity values in thousands of cubic metres per day. Key to abbreviations: FLASH =flash evaporator; SWM = spiral wound membrane; HFM = hollow fibre membrane; HTE = horizontal tube falling film evaporator;MTU = membrane type unknown; FM = flat membrane; VTE = vertical tube falling film evaporator; OTHER = other or unspecifiedequipment.

Capacity growth in the various technologies installed in the ESCWA member countries is summarized

in figure 1.13. The graphs comprising the figure indicate that the highest rates of growth have occurred inMSF technology, followed by RO and VC technologies. It should be noted that most of the earlierdesalination plants were based on MSF.

Figure 1.13 (a) indicates jagged but steady MSF capacity growth at an overall average rate of around240,000 m3/d per year during the period 1954-2002. An almost constant rate of increase in RO capacity,averaging around 75,000 m3/d per year, is observed. Following a period of moderate but accelerating growthduring the 1980s and 1990s, VC capacity made a substantial leap in the year 2000 owing to the establishment

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of 10 units in the United Arab Emirates with a total capacity of 225,000 m3/d. A somewhat similar pattern isseen with regard to MED capacity, which grew very slowly throughout the 1970s and 1980s, then jumpedsuddenly in 1987 following the establishment of four units in Yemen with a combined capacity of 57,600m3/d. Figure 1.13 (e) indicates no addition to MED capacity during the late 1980s and early 1990s, followedby limited capacity growth in the late 1990s. ED capacity growth was relatively robust during the 1970s andearly 1980s but slowed down considerably in the late 1980s and the 1990s. ED capacity appears to haveplateaued for most of the 1990s, as there are no indications of any sizeable capacity increases.

Figure 1.13. Cumulative capacity growth in different desalination

technologies installed in the ESCWA region(Thousands of cubic metres per day)

-

2,000

4,000

6,000

8,000

10,000

12,000

1

954

1

958

1

962

1

966

1

970

1

974

1

978

1

982

1

986

1

990

1

994

1

998

2

002

-

500

1,000

1,500

2,000

2,500

19

54

19

58

19

62

19

66

19

70

19

74

19

78

19

82

19

86

19

90

19

94

19

98

20

02

(a) Multistage flash (b) Reverse osmosis

-

150

300

450

600

750

195

4

195

8

196

2

196

6

197

0

197

4

197

8

198

2

198

6

199

0

199

4

199

8

200

2

-

50

100

150

200

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

(c) Vapour compressiona/ (d) Electrodialysis

-

20

40

60

80

100

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

(e) Multiple effect distillation


a/ Including both mechanical and thermal vapour compression processes.

4. Distribution of desalination capacity according to type of feed water

Figure 1.14 indicates that seawater is the main source of feed water in desalination plants in theESCWA member countries, constituting 83 per cent of the total. Brackish water accounts for 14 per cent,wastewater and river water represent 2 and 1 per cent respectively, and the use of brine and pure sourcewaters for desalination is negligible.

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Figure 1.14. Distribution of installed plant capacity in the ESCWA member countries according to

type of feed water in 2000 and as expected in 2003

Sea

83% (9,265)

Brine

0.1% (8)

Pure

0.1% (6)

River

2% (204)Waste

1% (63)

Brackish

14% (1,501)

Sea

86%

(12,871)

River

2% (286)Brine

0.1% (8)Pure

0.04% (6)

Waste

2% (313)

Brackish

10% (1,500)

(a) 2000 (b) 2003


Notes: Figures in brackets represent absolute capacity values in thousands of cubic metres per day. Brackish = brackish or

inland water, TDS 3,000-20,000 mg/l; brine = brine or concentrated seawater, TDS > 50,000 mg/l; pure = pure water, TDS < 500mg/l; river = river or other low-salinity water, TDS 500-3,000 mg/l; sea = seawater or concentrated seawater, TDS 20,000-50,000mg/l; waste = wastewater.

The distribution of feed water types has implications for desalination technology preferences, asshown in figure 1.15. The prevalence of seawater desalination in four of the five ESCWA member countriesunder consideration in the figure explains the extensive use of MSF technology (88-97 per cent).

Saudi Arabia leads the region in brackish water treatment, which may explain why it is also theregions major user of RO technology. It should be noted that at least 9 per cent of the countrys total ROcapacity could also be used to treat other categories of feed water, since brackish water treatment accountsfor 21 per cent of total capacity, while RO technology appears to account for around 30 per cent of alldesalination capacity in the Kingdom.

5. Analysis of desalination capacity in reference to areas of application

Desalination capacity dedicated to municipal uses in the ESCWA member countries totalledapproximately 9.3 MCM/d in the year 2000, accounting for around 84 per cent of total installed capacity (seefigure 1.16). This includes the water fed into municipal networks or otherwise distributed as drinking water,though an estimated 14 per cent of the municipal share is distributed for use by small industrial enterprises;the 12 per cent earmarked for industrial applications is probably fully dedicated to larger industrial plants. Aminiscule 0.1 per cent of desalination capacity serves the irrigation sector.

Figure 1.17 offers a chance for comparison, illustrating the main uses of desalinated water for threecountry groupings: Saudi Arabia and the United Arab Emirates; the remaining Gulf countries (Bahrain,Kuwait, Oman and Qatar); and ESCWA members with more diversified economies (Egypt, Iraq, Jordan,Lebanon, the Syrian Arab Republic and Yemen). Similar graphs for individual countries may be found in

figure A.1 in annex A.

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Figure 1.15. Distribution of installed plant capacity according to feed water type and desalination

technology used in five ESCWA member countries

(a) Kuwait

(b) Oman

(c) Qatar

(d)

Saudi

Arabia

(e)

United Arab

Emirates


Note: RO = reverse osmosis; ED = electrodialysis; HYBRID = hybrid (combined technologies); MED = multiple effectdistillation; MSF = multistage flash; VC = vapour compression; brackish = brackish or inland water, TDS 3,000-20,000 mg/l; brine =

brine or concentrated seawater, TDS > 50,000 mg/l; pure = pure water, TDS < 500 mg/l; river = river or other low-salinity water,TDS 500-3,000 mg/l; sea = seawater or concentrated seawater, TDS 20,000-50,000 mg/l; waste = wastewater.

Waste

0.4%Brackish

3%

Sea97%

Brine

0.2%

ED

0.2%

HYBRID

0.1%

MSF

97%

RO

3%

MED

0.1%

Brackish

3%

Sea

97%

MED

1%

VC

27%

RO

9%

MSF

89%

Sea

99%

Pure

0.2%Brackish1%

MED

0.4%

RO

2%

MSF

95%

VC3%

Brack

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