MEmbrane-based Desalination: An Integrated Approach

(acronymMEDINA)

INAMED

MEDINA web-site: http://medina.unical.it

one of the European STREP funded

projects in the still ongoing FP6

Contract No.: 036997

Duration: 2006-2009

ENIG

ICBM

UNSW

UTS

GVS

INSA

LOB

LCEE

CNRS

BGU

IWW

KWR

IHE

AR-VW

UNICAL

Short name

TunisiaEcole Nationale d’Ingénieurs de GABES / Institut

Supérieur des Etudes Technologiques de SFAX

GermanyCarl von Ossietzky University of Oldenburg, Institute for

Chemistry and Biology of the Marine Environment

AustraliaUniversity of New South Wales

AustraliaUniversity of Technology, Sydney

ItalyGVS S.P.A.

FranceINSA Toulouse

a) Laboratoire d'Océanographie Biologique

b) Laboratoire de Chimie de l'Eau et de l'Environnement

France

Centre National de la Recherche Scientifique:

IsraelBen Gurion University

GermanyUniversität Duisburg-Essen-IWW

The NetherlandsKIWA

The NetherlandsUNESCO – IHE

FranceAnjou Recherche – Veolia Water

ItalyUniversity of Calabria

CountryParticipant name

List of Participants

Aim of the proposal…

…to improve the current design and operation practices of membrane systems

used for water desalination. While research, testing and validation activities are

conducted to assess the existing limitations and issuesrelated to membrane

desalination and improve its efficiency and reliability,

Broader studies are undertaken to develop and propose innovative strategies to

minimise environmental impactsand optimise energy sources and consumption.

The proposed approach is innovative and is based on the integration of different

membrane operations in RO pre-treatment (MF/UF/Membrane

Bioreactor/NF/Membrane Contactor) and post-treatment stages

(MC/MD/Membrane Crystallizer/WAIV working on the concentrates) according to

the philosophy of Process Intensification.

EVOLUTION

REVOLUTION

Graphical presentation of links between WPs

� new and modified techniques for predicting scaling of SWRO and BWRO membranes.

Work Package 1: Water Quality Assessment Tools

The goal of WP 1 is the development and validation of:

� advanced analytical methods to characterize natural organic matter (NOM) and biological matter contained in seawater and brackish waters;

� new and modified approaches beyond the silt density index (SDI) to predict particulate/colloidal fouling;

� protocols for predicting biofoulingpotential;

Cross-Disciplinary Approach of WP 1

Achieved results: Various analytical protocols and surrogate bench-scale tests have been developed to

quantify the quality of pre-treated water prior to application of RO in terms of fouling potential

with respect to:

(i) particulate/colloidal fouling

(ii) natural organic matter (NOM) fouling

(iii) biological fouling (biofouling)

(iv) inorganic fouling or scaling

MayJulAugSepOctDecJanFebMar

MayJulAugSepOctDecFebMar

MayAugSepOctDecFeb

MF

DF

RW

CO

MP

LE

XIT

Y

rDNA profiles: before/after prefiltration

RW

BW

AUG

SEP

OCT

JUL

DIV

ER

SIT

Y C

HA

NG

E

(v) SSCP profile comparison indicates loss of dominance for some groups major represented in RW

samples as compared to samples after pre treatments. Comparison with what is present in the

membrane might allow the identification of first colonizers and their role in biofilm formation.

LOB contribution

WP 2: Evaluation and Comparison of Seawater and Brackish Water Pretreatment Processes

Objectives:

� Conduct a full-scale plant evaluation on available pretreatment approaches for

sea/brackish/estuarine/bay water.

� Evaluate and compare the cost and the efficiency of conventional processes (e.g. Dual

Media Filtration, flocculation/coagulation and antiscalant) and novel methods of pre-

treatment for sea water RO.

Achieved results: Different pretreatment methods (such as microfiltration, ultrafiltration,

nanofiltration, powdered activated carbon adsorption and ferric chloride flocculation) were

evaluated in terms of their capability in removing seawater organic matter and the characteristics of

the foulants on the seawater reverse osmosis membranes.

AR-VW Contribution: Seawater pretreatment – pilot study-

Granular Pretreatment vs Membrane Pretreatment

H2SO4pH=6.8

FeCl3 Polymer

Open Intake

Sand removal

RW tank

Anthracite

Sand

Cartridge filter 5µm

SWRO Dow 1 pressure vessel SW30 HRLE 4040

R=20% Flux=19.6LMH

Train 1 : Flocculation + dual-media filtration

Flocculation

Microfiltration Jp=50 LMH

Train 2: Submerged microfiltration

Pretreated water tankDual-

media Filtration

Cartridge filter 5µm

SWRO Dow 1 pressure vessel SW30 HRLE 4040

R=20% Flux=19.6LMH

WP 2: Evaluation and Comparison of Seawater and Brackish Water Pretreatment Processes

Pretreated Water Quality

Pretreatment Performance - Particulate-related WQ parameters

SDI15<3

(%) SDI15<3.5

(%) Average SDI15

Turbidity (NTU)

Particle > 1µm count

(mL-1) Granular Filtration

25 55 3.5 0.03 160

Microfiltration 94 99 2.5 0.03 70

Pretreatment Performance - Organics-related WQ parameters

DOC (%)

Polysacccharides (%)

Bacteria (Log)

Plankton (Log)

Chlorophyll (%)

Granular Filtration

13 38 0.6 0.8 93

Microfiltration < 5 12 1.8 > 4 > 95

WP 2: Evaluation and Comparison of Seawater and Brackish Water Pretreatment Processes

Granular Dual Media Filtration

Microfiltration

AR-VW Contribution

Comparison of the hydraulic performances of 2 RO units fed by seawater pretreated by MF (red) or granular filtration (blue)

0,5

0,6

0,7

0,8

0,9

1,0

1,1

1,2

mai-07 juin-07 juil-07 août-07 sept-07 oct-07

No

rma

lized

RO

Per

mea

te F

low

(%

)

RO-Granular Dual Media Filtration

RO-Microfiltration

WP 2: Evaluation and Comparison of Seawater and Brackish Water Pretreatment Processes

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

0 8 17 25 33 42 50 58 67 75 83 92 100 108time

OC

D

O3 -f - 12 ppm C

oi 1-f - 2.8 ppm C

7202-7201-7248

injection 100/1000 - dilution 8Polysaccharides, ProteinesColloides inorganiquesProteinesProtéines, sucres aminésMM > 50 000 g/mol

SH + BB SH + BBSH + BB

100 - 10 000 g/mol

Acids organiques (AO)Acids humiques MW < 350 g/mol

Neutres (LMM)Neutres MW < 350 g/mol

DOC(µg/cm²)

0.2

1.0

MembraneRO-

Granular

MembraneRO-MF

Quantity of dissolved organic matter significantly higher on RO-MF deposit

RO-Granular deposit � mainly made of high molecular weight organic compounds (> 50 000 g/mol) like polysaccharides and amino-sugars

RO-MF deposit � same as RO-Granular deposit + lower molecular weight organic compounds (< 350 g/mol)

Microfiltration

Granular filtration

WP 3: RO Fouling Characterization and Understanding

WP 3: Development of Tools for RO Fouling Characterization and Understanding. (1) Several methods to characterize deposit at the membrane surface, (2) detailed autopsies to identify species responsible of fouling, (3) biofouling and scaling techniques to understand mutual effects between organic fouling, biofouling and scaling at membrane surface and (4) effect of modern antiscalants on biofouling development have been

developed and validated.

Autopsy tools

Biofouling

Organicfouling

Scaling

FTIR / ATR-FTIR

Elementalanalysis

ICP

SEM-EDXEPS, BDOC and ATP

measurements

Carbon and NitrogenOrganic analysis

Molecularmethods

13C-NMR and 15N-NMR

Pyrolysis-GC/MS

Carbohydrates, Aminoacids and lipids

quantification

Total and Active Bacteria quantification

SEC/ DOC-DON-UV

Raman microscopy

EEM fluorescence

Confocal laser microscopy

X-Ray diffractionHeterotrophic

Plate countAFM

SEM

RO membrane opening Deposit scrapping

Autopsy tools

ORGANIC FOULING

EEM fluorescence

LC-OCD

SCALINGBIOFOULING

Bacteriaquantification

EDXSEM

EPS, BDOC and ATP measurements

AFM

I n s o l u b l e f r a c t i o n

S o l u b l e f r a c t i o n

T o t a l d e p o s i t

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1 , 0

1 , 1

1 , 2

Abso

rbance

1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0

W a v e l e n g t h ( c m - 1 )

165

1

154

2

1407

123

6

107

9

1040

I n s o l u b l e f r a c t i o n

S o l u b l e f r a c t i o n

T o t a l d e p o s i t

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0 , 4

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0 , 9

1 , 0

1 , 1

1 , 2

Abso

rbance

1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0

W a v e l e n g t h ( c m - 1 )

I n s o l u b l e f r a c t i o n

S o l u b l e f r a c t i o n

T o t a l d e p o s i t

0 , 3

0 , 4

0 , 5

0 , 6

0 , 7

0 , 8

0 , 9

1 , 0

1 , 1

1 , 2

Abso

rbance

1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0

W a v e l e n g t h ( c m - 1 )

165

1

154

2

1407

123

6

107

9

1040

ATR-FTIR

Achieved results: a) Microorganisms, implied in the biofouling phenomenon, were identified using methods of culture and molecular biology (SSCP and clone libraries); a link was established with the RO feed water quality; b) The organic content of the biofilm was deeply investigated by focusing mainly on Exopolymer Substances (EPS); c)The efficiency of chemical cleanings was evaluated through the removal of the different foulants.

WP 3: Development of Tools for RO Fouling Characterization and Understanding

WP 4: Development of Cleaning Strategies for RO

Membranes

Results: a) A questionnaire has been developed for conducting a survey of

practical cleaning experiences. b) Selection of locations for full scale plants and

pilot plants was carried out. c) A laboratory procedure has been developed using

sections cut from plastic tubing (PVC-P) on which a biofilm was grown to test the

efficacy of cleaning agents and cleaning procedures. d) Several cleaning agents

were investigated. e) Concentrations of attached biomass were determined with

ATP analysis and Total Direct cell counts (TDC). f) A procedure has been

established to generate defined fouling layers for testing the efficacy of cleaners

towards different foulants.

To increaseplant globalRecovery

Factor

To reduceBrine

DisposalProblem

To recoverCrystals

Membrane Crystallizer as NF/RO post-

treatment...for the concentration and crystallization of

retentate

Objects: 1. to identify alternative design pathways for brine concentration in order to increase the

recovery of desalted water and to limit the environmental impact of discharged concentrates; 2. to

recover the most part of valuable salts (calcium sulphate, sodium chloride, epsomite, etc.) that are

present in large amount in the concentrated streams produced by innovative crystallization

techniques (MD, MCr, WAIV).

WP 5: Process strategies for mitigation of

impact of concentrates on the environment

95,3638,9021,90

95,2739,3617,05

95,0238,7412,22

NF+MCr

recovery

factor[%]

Feed

Temperature

[°°°°C]

Produced salts

[g/L]

Results: a) A software to describe and

simulate vacuum MD for high salt

concentrations was developed. The

model for MD has been also adapted to

simulate coupling with solar system. b)

Tests of Membrane Crystallization

(MCr) and wind-aided intensified

evaporation (WAIV) have been

performed in order to reduce the

amount of brine discharged from RO

and NF. Recovery factors > 95% for the

coupled desalination system NF+MCr

have been obtained.

MCr tests on NF brine: amount of produced

salts and recovery factor

WP 5: Process strategies for mitigation of impact of concentrates on the

environment

UNICAL contribution

WP 6: Innovative Technologies to Reduce Energy Consumption in Seawater Desalination Facilities

Definitionof membraneand moduleconstraintsin relation with process operation

Design of two different modulesforlab-scale studies

Technico-Economical evaluationof the two processes and choiceof a process

Design of a demonstrationplant and a semi-industrialscale pilot plant

Installation and start-up of the demonstrationplant

Membrane manufacturing

Membrane characterisation

Study and definitionof the solar system

Manufacturing of lab-scale and demonstrationmodules Lab-scale

testing of the two processes

Modelling of MD in these new systems

Lab-scale testing of the selectedprocess

In order to achieve this goal, the design and demonstration

of new separation systems based on an integrating coupling

of membrane distillation and solar energy is considered.

Microporous hydrophobic flat and hollow fiber membranes

have been prepared, characterized ad applied for vacuum

membrane distillation (VMD) tests.

Rétentat

T

T

T

Alimentation Eau de mer

Échangeur

Ta

?

Perméat

P

Pompe à vide

Condenseur

T

T

T

T

P

Membrane distillation included in a cylindro-paraboloidal heat concentrator.

The goal is to study, design, test and

demonstrate at lab-scale or on

experimental platforms innovative

technologies for decreasing energy

consumption for seawater

desalination processes using the

concept of integrated membrane

desalination system.

Distillate flux for different flat membranes(60°C, 20 mbar)

010

2030

4050

6070

8090

100

J [K

g*m

-2*h

-1]

M09t M09 M05 M07

Hollow fibers spinning

Reduced finger-like portion

High porosity

Hollow fibers characterisation by SEM Distillate fluxes improvements with hollow fibers (50°C, 60 mbar)

(UNICAL contribution)

Feed tank

Pump

Membrane module(40 cm2)

CO2 bottleFeed tank

Pump

Membrane module(40 cm2)

CO2 bottle

membranes in a lab module of 40 cm2. In particular, the

oxygen removal and the pH variations have been

monitored for different streams of an integrated

desalination plant (seawater, RO/NF permeate, RO brine).

Moreover, tests for As oxidation in membrane contactors

have been performed. The preliminary results are quite encouraging, confirming the

potentialities of these systems for desalination operations. (UNICAL contribution)

b) Tests for controlling the water gas composition have been carried out both on commercial and flat

WP 7: Optimization and Modelling of Seawater and Brackish Water Reverse

Osmosis Desalination Processes

a) A Laboratory Test Unit for small

spiral wound elements has been

designed as a two dimensional flat

sheet test cell and it will be used for

collecting experimental data to run

the Neural Net program.

(IWW contribution)Photograph of the planned laboratory cell

MC MCMC

MC

NF ROFeed Permeate Permeate

Brine

Membrane contactors used in different points of the desalination plant.

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80

Feed (g/L)

O2

rem

oval

(%

)

H2Od

RO permeate

NF permeate

RO brine

NF feed

Effect of the liquid composition on

the oxygen removal for 1 hour of

test.

Depending on the gas used as strip, the

oxygen removal has been successfully

coupled to a pH increase up to 30% (with

nitrogen) or to a pH decrease down to

33% (with carbon dioxide) without any

use of chemical agents.

(UNICAL contribution)

WP 7: Optimization and Modelling of Seawater and Brackish Water Reverse

Osmosis Desalination Processes

c) 3D Computational Fluid Dynamics (CFD) study of 3-layer spacer geometries for application in RO SWM modules(UNSW contribution)

Geometries

Cost analysis

– Due to its lower pressure drop, the A3LS-0º geometry results in lower permeate processing costs than both 3D orientations

– Despite it higher pressure drop, the higher Sherwood number attained by the A3LS-90º geometry results in a smaller membrane area required, and thus lower overall processing costs.

(UNSW contribution)

The main goals of the WP are:

� To furnish a critical state of the art of the desalination technology

� To develop and optimize an integrated membrane system for improving desalination efficiency

� To evaluate and compare the costs associated to the integrated membrane system with respect to conventional technologies

� To evaluate existing and new metric indexes,consistent with the Logic of Process Intensification, in order to facilitate the selection between different options.

Work Package 8: Integrated system configuration

WT 8.1: Critical State of the Art of the Desalination

Technologies

WT 8.4: Economic evaluation of the integrated

membrane system

WT 8.3: Optimization of the integrated system

configuration

WT 8.2: Study of different integrated systems

Feed water

MF/UF NF NF/RO

MC MC

Desaltedwater

MD/MCr

MD/MCr

Desalted

water

Salts Brine

Salts Brine

Desalted

water

MC

GAS

(OUT)

NF/RO PERMEATE(IN) (OUT)

(IN)

Heater

(IN)

(IN)

RO/NF RETENTATE(OUT)

(OUT)

Filter

The integration of different membrane systems

for water desalination

A possible integrated membrane desalination flow-sheet for sea-brackish water desalination optimized also by understanding, controlling and minimizing fouling phenomena

First results:

a) A critical analysis on the current desalination technologies has been carried out, in

order:

i) to individuate the main items which have to be developed and/or improved;

ii) to identify possible strategies for reliable solutions.

b) An integrated membrane system (MBR/NF-RO/MD-MCr) in lab-scale for carrying out

experimental tests has been built, in order to analyse how the single and the overall

performance will change because of the synergic interactions.

NF/RO lab unitMBR as pre-treatment step Distillation/Crystallization step

WP 9: Environmental Impact Assessment and Life Cycle Analysis

(LCA) of Membrane-Based Desalination Plants

Results:

a) Scope and formal requirements of an EIA study for membrane desalination plants

have been investigated in the Deliverable D 9.1, starting from existing general EIA

frameworks and manual, which have been adjusted to membrane desalination plants.

The deliverable has been published by the United Nations Environment Programme

in a UNEP/WHO joint guidance document on desalination.

b) The analysis of the relevant impact of membrane desalination plants is in progress.

The stage of data gathering and evaluation of information sources has been completed

and the preparation of a draft is currently available on the MEDINA web site.

The objective of WP9 is to develop adequate assessment tools and instruments for

Environmental Impact Assessments (EIA) and Strategic Environmental Assessments

(SEAs or strategic EIAs) specific to the conditions and requirements of membrane

desalination facilities.

ICBM contribution

Plan for using and disseminating knowledge

�Press releases(such as Arab Water World, Bollettino della Comunità

Scientifica in Australasia, etc.);

�Several MEDINA project presentations and updates (such as

MEDINA presentation for MEDIA CONSULTA and the poster for The

European Water Research Day - Zaragoza EXPO 2008);

�Various manuscripts and articles;

�Different conference presentations;

�The EU-CHINA WORKSHOP in Qingdao (CHINA) - September 2009.

The MEDINA project team is liaising and engaging active

communication with other European and not European projects on

water management strategies, such as the following:

� MEDESOL: Seawater desalination by innovative solar-powered

membrane-distillation system

� SeaHERO: Seawater Engineering Architecture High Efficiency

Reverse Osmosis project. The interest of SeaHERO has been confirmed

by the presence of Prof. In S. Kim, Executive Director of the Center for

Seawater Desalination Plant, with two of his colleagues at the Second

Annual MEDINA meeting at BGU

Links with other national and international research activities

Conclusion: Membrane operations are playing today a strategic important

role in sea/brackish water desalination.

MEDINA has managed to solve some current issues

…and might overcome some crucial limitations (recovery factor, brine

disposal problem and environmental impact, etc.) through an overall

integrated membrane system.

Source: IDA/GWI Desalination Plant Inventory, 2008

Contact for further information:

� MEDINA website: http://medina.unical.it

� Project Coordinator: Prof. Enrico Drioli

Director of the Institute on Membranes and Chemical

Reactors of the National Research Council

University of Calabria

Department of Chemical Engineering and Materials, via P. Bucci

cubo 17/C 87030 Rende (CS), ITALY

e.drioli@itm.cnr.it, e.drioli@unical.it

Tel: +39 0984 492039

Fax: +39 0984 402103