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MEMBRANE FILTRATION PROCESSES
Membrane processes in drinking water treatment
Microfiltration (MF) and Ultrafiltration (UF)
2nd French-Serbian Summer School
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 2
Principles of membrane processesDrivers for expansion of membrane technology in Eur ope
� More stringent water quality regulations� Turbidity� Cryptosporidium (regulated in UK)� Pesticides� …
� Efforts from private companies to: � Exceed current/anticipated regulations� Provide sustainable solutions� Make technology available (reliability/cost) for municipal
applications through strong R&D efforts� Minimize O&M cost for small remote plant and maintain high
water quality
� Higher consumer expectations� Lack of fresh water resource in Mediterranean region and
Islands (�desalination)
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1988 1990 1992 1994 1996 1998 2000 2002 2004
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MEMBRANE FILTRATION PROCESSES
Principles and Theory
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 4
Principles of membrane processes Contents
� Principles and Theory
� Principles of membrane processes
� Membrane disinfection properties
� Filtration modes, materials and geometry
� Membrane operating parameters
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 5
Hardness X X
Sulfates X X
Monovalent ions (fluorine, nitrates,…) X
Parameters MF UF NF RO
Turbidity X X
Bacteria and cysts (Giardia, Cryptosporidium…) X X
Virus X
Color X X
Organic matter and disinfection by-products X* X
Micropollutants (pesticides, taste+odor) X
X*
X*
* Removal by CristalTM process (Aquasource UF membranes combined with powdered activated carbon)
Principles of membrane processesApplications
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 6
Principles of membrane processesTypes of membrane filtration processes
desalinationdiscoloration removal of pesticides, taste + odor, nitrates
90-99 % ions99 % organic molecules
Reverse osmosisRO
softeningpartial desalinationdiscoloration removal of pesticides, taste + odor, sulfates
95% bivalent ions30-60% monovalent ions99% organic molecules (molar weight > 200 – 400 )
NanofiltrationNF
clarificationdisinfectionpretreatment for NF and RO
some macro-moleculesUltrafiltration
UF
clarificationpretreatment for NF and RO
All particles except some virusesMicrofiltrationMF
Applications in drinking water treatment
Effectiveness of treatmentType of filtration
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 7
Principles of membrane processes Contents
� Principles and Theory
� Principles of membrane processes
� Membrane disinfection properties
� Filtration modes, materials and geometry
� Membrane operating parameters
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 8
n = number of analysesND :none detectedn = 10
n = 10
n = 10
Raw waterFiltered water
MS2 Bacteriophages
MFB 0.2 µmMFA 0,2 µm UF 0.01µmAquasource
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
MS
2 B
acte
rioph
ages
, pfu
/ml
ND
Membrane disinfection propertiesComparing disinfection by Micro- vs. Ultra- filtratio n
UF is effective for virus removal
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 9
Membrane disinfection propertiesDisinfection by UF vs. conventional disinfectants
Viruses8 mg/l.min
4 log13 mg/l.min
2 log1,6 mg/l.min
4 logEscherichia Coli bacteriophage
Protozoa
9 logPolio virus Type I
> 5 logBacteriaColiformsThermo tolerant coliforms Fecal EsteptocoquesClostridium
Aerobic microorganisms (22 –37°C)
> 5 log70 mg/l.min2 log
7200 mg/l.min10 mg/l.min4 log
Cryptosporidium cysts
10 mg/l.min4 log
18 mg/l.min2 log
2,4 mg/l.min4 log
Giardia cysts
4 - 5 log20 mg/l.min2 mg/l.minAmeba cysts
UFChlorine dioxide
ChlorineOzone
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 10
Principles of membrane processes Contents
� Principles and Theory
� Principles of membrane processes
� Membrane disinfection properties
� Filtration modes, materials and geometry
� Membrane operating parameters
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 11
Filtration modes, materials and geometryHollow fiber internal vs. external filtration
Internal filtration
inlet water Permeate
concentrate
External filtration
inlet water
concentrate
Permeate
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 12
Filtration modes, materials and geometryDead end vs. Cross flow filtration
Dead-end filtration
Cross-flow filtration
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Filtration modes, materials and geometryImmersed vs. pressurized filtration
Pressurized filtration
Immersed filtration
Aeration
Permeate
for
backwash
. … ..
.. . .. ..
. .. . ..
. … ..
.. . .. ..
. .. . ..
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 14
Filtration modes, materials and geometryMembrane materials
organic film + mineral supportHybrid
alumina, silicium carburate, titanium oxide, zirconium...
Inorganic (Mineral)
cellulose acetate, polysulfone, polypropylene, polyacrylonitrile, polyester, polymide, Polyether sulfonepolytétrafluoroethylene, vinylidene polyfluorure
Organic (Polymers)
Polymeric membrane are mainly used for drinking water treatment
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 15
Filtration modes, materials and geometryUF & MF membrane materials
Cellulose Poly(ether)sulphone
Hydrophilic Hydrophobic / Hydrophilic
Fouling (organic adsorption) Low Fair/Medium
pH tolerance Narrow (3 - 8.5) Wide (2 - 13)
Biological degradation yes no
Chemical resistance Low (Chlorine) Good
Aquasource HydraCap
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 16
Filtration modes, materials and geometryMembrane configurations
� Flat membranes (organic)
� spiral modules
� plate modules
� Cylindrical membranes (organic, mineral)
� hollow fiber or capillary fiber modules
� tubular modules
Hollow fiber are mainly used for drinking water treatment
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 17
Filtration modes, materials and geometryExample of advantages/disadvantages of UF configuration
Tubular Capillary Plate&Frame Spiral-Wound
Cost/area High Low High Low
Flow Good Good Low Low
Packing density, m²/m3 Poor Excellent Good Good
Energy consumption High Low Medium Medium
Fouling Excellent Good/Fair Good/Fair Medium
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 18
Filtration modes, materials and geometryFlat - spiral membrane
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Filtration modes, materials and geometryFlat – spiral membrane: Filmtec module
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 20
Filtration modes, materials and geometryHollow fiber membrane – typical pressurized module
Hollow fibersSupport grid
ResinInlet waterunder pressure
Filtered water outlet
Outlet for removed particles
Aquasource ND 300 – 64 m²
HYDRACap 60– 46 m²
Hollow-fiber capillary membrane
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 21
Filtration modes, materials and geometryHollow fiber membrane
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 22
Filtration modes, materials and geometryHollow fiber immersed membrane – Gentle vacuum
external film
ZeeWeed®
module
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 23
Filtration modes, materials and geometryTubular membrane – TAMI modules
Permeate
Concentrate
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 24
Principles of membrane processes Contents
� Principles and Theory
� Principles of membrane processes
� Membrane disinfection properties
� Filtration modes, materials and geometry
� Membrane operating parameters
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 25
Permeate(filtrate)
Concentrate(retentate)
Feed(raw water) Pump
PIN
POUT
PP
Membrane
Module
Valve
QF
QP
Membrane operating parametersMembrane language
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 26
Membrane operating parametersMembrane filtration phenomena
Permeate
Filtration
Feed
Concentrate
Backwash
Fouling ⇔⇔⇔⇔ Permeability (Lp) ↓↓↓↓
TransMembrane Pressure (TMP)↑↑↑↑
Clogging ⇔⇔⇔⇔ Head loss (∆∆∆∆P)↑↑↑↑
Permeate
Waste
Waste
Removal of reversible fouling ⇔⇔⇔⇔ Permeability ↑↑↑↑, TransMembrane Pressure ↓↓↓↓, Head loss ↓↓↓↓
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Without backwash With backwash
Irreversible fouling
Permeability (L p 20°C )
Time
Reversible fouling
Membrane operating parametersMembrane performance evolution with time
MEMBRANE FILTRATION PROCESSES
Market and development for membrane technology
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 29
Membrane technology market and development Contents
� Market and development for membrane technology
� Major manufacturers / suppliers
> Norit
> Aquasource
> Memtec
> Zenon
> Kalsep
� Market growth
� Costs
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 30
Major manufacturers / suppliers Overview
� 8 major membrane manufacturers/suppliers
� Organic hollow fiber technology dominates
� No ceramic technologies implemented for drinking water production since 1991
� Ultrafiltration is the preferred technology for drinking water applications
� Netherlands, France, and UK represent 85% of the contracted MF/UF capacity in Europe
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 31
Major manufacturers / suppliers Suppliers identified in Europe for municipal applic ations
Manufacturer Process Type Backwash Material
X-Flow (The Netherlands) MF/UF module Int Water PES
Aquasource (France) UF module Int Water CA
Memtec (Australia) MF module Ext Air PP
Acumem (UK) MF module Ext Water PES
Zenon (Canada) UF cassette Ext Air/water PVDF
Hydranautics (USA) UF module Int Water PES
Asahi Pall (Japan) MF/UF module Int Air/water polyacril on.
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 32
Major manufacturers / suppliers Norit membranes: X-Flow modules
8 inch modulesSurface area 22 � 35 m2
Reference: Clay Lane1st stage: 1 536 modules, 160 000 m 3/d2nd stage: 144 modules (concentrate treatment)
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 33
Major manufacturers / suppliers Aquasource membranes
DN300 Modules: 55 m 2 64m2
Lausanne, Switzerland(396 modules, 40 000 m 3/d)
DN450 Modules :125 m 2
Rouen, France(96 modules, 24 000 m 3/d)
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 34
Major manufacturers / suppliers Memtec membranes
CMF system (pressurized)
CMF-S system (submerged)
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 35
Major manufacturers / suppliers Zenon membranes
ZeeWeed Organic fibers0,035 µm cut-off450 m2
excesssludge
permeate
Feed
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 36
Major manufacturers / suppliers Zenon cassette trains
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 37
Major manufacturers / suppliers Kalsep membranes
HYDRAcap module
HYDRAcap systemBirchtrees WTW 1.6 Ml/d
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 38
Membrane technology market and development Contents
� Market and development for membrane technology
� Major manufacturers / suppliers
� Market growth
� Costs
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 39
Market growth Application of membrane technology in municipal wat er treatment in Europe (growth)
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1988 1990 1992 1994 1996 1998 2000 2002 2004
Hydranautics 2001Kalsep 2000Pall 1998Norit 1995Acumem 1996Zenon 1994Memtec1993Aquasource 1988
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 40
Market growth Application of membrane technology in municipal wat er treatment in Europe (figures)
Total installed plant Application
NA : Not available
Acumen UF 46 4 21 100 -Aquasource UF 120 65 32 100 -Hydranautics UF 19 20 5 100 -Kalsep UF 16 9 5 100 -Memtec MF 92 14 21 100 NAPall MF 4 12 2 - 100Norit UF 142 43 43 100 -Zenon UF 31 29 12 1 99
Total 8 468 196 43 93 7
Largest PlantProcess Capacity Number Capacity Drinking water Wastewat er
mgd mgd % capacity % capacity
1 MGD = 3 785 m3/day
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 41
<5
5-10
10-25
>25
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Market growth Municipal WTP's in Europe using membrane technology
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 42
Market growth Municipal WTP's in Europe using membrane technolog yDistribution by country
0 100 200 300
DenmarkNorwayIrelandPoland
HungaryBelgium
SpainSlovenia
ItalyGermany
NetherlandsFrance
UK
Drinking waterWastewater
Capacity, mgd
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 43
Membrane technology market and development Contents
� Market and development for membrane technology
� Major manufacturers / suppliers
� Market growth
� Costs
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 44
Costs Capital and operating costs for membranes processes
Total water costTotal water cost Capital costCapital cost
€/m€/m33 €/m€/m33.d.d
MF/UFMF/UF 0.15 0.15 -- 0.3 0.3 150 150 -- 450450
NFNF 0.3 0.3 -- 0.5 0.5 400 400 -- 600600
RORO 0.45 0.45 -- 1 1 900 900 -- 13001300
Costs highly depend on facility capacity
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 45
Costs Operating cost distribution for membranes processes
� MF
� UF
� NF
� RO
� RO desalination
pressure bar
energykwh/m 3
0,1
0,1
0,4
0,6
2,4/3,1
cost$/m3
0,01
0,01
0,04
0,06
0,30
membranes$/m3
0,03
0,03
0,02
0,02
0,02
2
2
7
12
65/90
MEMBRANE FILTRATION PROCESSES
Membrane processes in drinking water treatment
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 47
Membrane development within SE
1985
R&D CIRSEE
1ère réalisation: Amoncourt 1991
Orléans 200540 000 m3/j L’Apié
25 000 m3/j
Vigneux55 000 m3/j
Helbarron16 000 m3/j
55 usines exploitées
par LdE
1988
1997
19962004
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 48
Membrane processes Contents
� Membrane processes in drinking water treatment
� Design considerations
� Typical treatment train� Direct filtration
� Polishing: Clarification + UF
� Polishing: Clarification + GAC + O3 + UF
� Pretreatment for Reverse Osmosis
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 49
DesignHow designing a membrane system?
� To clearly define the future WTP objectives�Treated water quality�Water production capacity and anticipated annual variations
As hydraulic performance of a membrane systemclosely depends on the quality of water to be treated
⇒⇒⇒⇒ To do a CASE BY CASE design
� To characterize raw water quality and identify peak periods during the year
� To carry out a pilot study on future raw water to w ork out:�Process design parameters�Operating conditions
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 50
DesignHow define the WTW size ?
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50
100
150
200
250
1-jan
v
1-m
ars1-
avr1-
mai
1-jui
n1-
juil
1-se
pt1-
oct
1-no
v
Flo
wra
tet,
Ml/d
ay
Flux 180 LMH Flux 150 LMH LAR 2002
� To clearly define the need of the WTW in terms of quantity
� Historical data
� Alternative supply
� Adjust design considering flow variation though out the year (water quality, temperature, …)
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 51
DesignHow characterizing raw water quality?
� TOC : Total Organic Carbon
� DOC : Dissolved Organic Carbon
� UV : absorption UV @ 254 nm
� Algae
� Turbidity
� Temperature
� Iron, Manganese, Aluminium, silica
Organic fouling
Mineral fouling
Productivity
Main parameters with an impact on membrane performance:
Filtration mode
Establish the design on appropriate water quality data
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 52
DesignMeasuring organic matter
� UV absorbance measures levels of aromatic and unsaturated organic matter
� The UV/TOC ratio is often correlated to certain treatment parameters such as potential for formation of trihalomethanes (THM's) or other organic matter content such as PHA
UV/COT ~ 1 - 2 mg/l low
2,0 - 4 medium
> 4 - 5 high (humic matter)
• high amount of PHA (polyhydroxy-aromatics)
• high and irreversible affinity with membrane material
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 53
DesignRaw water quality impact on membrane operating cond itions
Categories Tub, NFU Filtration mode Flux, LMH @ 20°C Ba ckwash, min. CC, nbr/yr
0 <0.5 Dead-end 120 to 150 60 to 90 1 to 21 < 2 + spike Dead-end 100 to 120 60 to 90 1 to 22.1 < 6 + spike Cross-flow 90 to 110 30 to 45 4 to 62.2 2 to 4 + spike Cross-flow 80 to 100 30 6 to 82.3 < 6 + spike Cross-flow 70 to 80 30 63.1 > 6 + spike Cross-flow 60 to 70 30 6 to 123.2 > 6 + spike Cross-flow 40 to 50 30 12
Example: water categories for Aquasource membranes
0 1 2 3 4 5 6 7 8 9 10 11 12
DOC (mg/l)
0
1
2
3
4
5
6
7
8
UV
/DO
C
1
0
2.1 3.1
3.2
2.3
3.1
3.2
2.2
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 54
DesignConstraints of membrane technology as clarification stage
� If raw water quality is out of the recommended ranges,
a pre-treatment is necessary:
� Turbidity > 300 NTU ���� Settling
� Organic matter TOC > 4 mg/L ���� pretreatment and PAC/UF
� Algae > 6 - 10 x 106 /L ���� Flotation, O 3, PAC/UF
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 55
Membranes in drinking water treatmentDifferent configurations according to raw water qua lity
Type of Raw Water
POLISHING AFTER CONVENTIONAL TREATMENT (Disinfection)
PRE-TREATMENT FOR REVERSE OSMOSIS
DIRECT FILTRATION (Clarification + Disinfection)
Surface waterLake / clean
surface waterGroundwater
Combined membrane treatment
Ultrafiltration
Cl2
With or without PAC
or
Cl2
Coagulant
Polymer
Sandfiltration Ultrafiltration
Settlingor flotation
(O3)
With orwithout PAC
(CAG)
Cl2
MF/UF NF/RO(O3)
With orwithout PAC
(CAG)
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 56
Membranes in drinking water treatmentWhy injecting PAC upwards the UF membranes?
Applications:
• For treating raw water containing:High organic matter concentrationsMicro-pollutants
• For polishing:Removal of organic matterRemoval of taste & odor precursors
Operating conditions:
• Cross-flow filtration• Dosing rates 5 to 20 g/m 3
• Continuous dosing• Dosing depending on thresholds of turbidity, TOC, U V
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 57
Membranes in drinking water treatmentEffect of injecting PAC upstream the UF membranes
0
200
400
600
800
1 000
1 200
1 400
0 1 2 5 7 8 9 10 11
Time (days)
arrêt injection CAP avant le préfiltre
0
200
400
600
800
1 000
1 200
1 400
0 1 2 5 7 8 9 10 11
Shut-down PAC injection prior to pre-filter
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 58
DesignWhy conducting a pilot study?
1/ To confirm theoretical process design on a specific case
⇔ To follow the evolution of permeability with time, depending on raw water quality
2/ To fine tune design parameters
⇔ To conduct lab test (adsorption isotherm & kinetics) to determine the PAC contact time and doses for specific water
3/ To determine optimal operating conditions (max flow rate, min water losses)
⇔ To increase, by steps, flux and filtration cycles and follow up permeability vs time
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 59
DesignPilot study: a viable option for plant design ?
Flu
x, L
/h.m
², P
erm
éabi
lity,
L/h
.m².
bar
WQ 1 WQ 2
15 - 27/11/01 19 - 25/09/020
50
100
150
200
250
300
Jp Jp à 20°C Lp à 20°C
To study the impact of the water quality to be trea ted
0
0,5
1,0
1,5
2,0
2,5
CO
T (
mg/
L) e
t U
V (
DO
/m)
0
200
400
600
800
1 000
1 200
Par
ticul
es/m
L -
SD
I*10
0TOC UV Particles SDI
15 - 27/11/01 19 - 25/09/02
WQ 1 WQ 2
� Difficult to predict fouling behavior only with water characteristic
� Compounds not identify thru TOC / UV even SDI
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 60
Membrane processes Contents
� Membrane processes in drinking water treatment
� Design considerations
� Typical treatment train� Direct filtration
� Polishing: Clarification + UF
� Polishing: Clarification + GAC + O3 + UF
� Pretreatment for Reverse Osmosis
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Membranes as direct filtrationExample: L’Apié WTP, France (28 000 m 3/d)
Chlorine
PAC10 mg/L
Pre filter 200 µm
Discharge(to DENSADEG)
8 x 20 modules
DN300
Lakewater
Raw water (lake):- low turbidity- micropollutants (pesticides, nitrates, …)- organic matter- microbial contamination
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 62
Membranes as direct filtrationExample: L’Apié WTP, France (28 000 m 3/d)
Raw water Treated waterAverage (Min-Max)
Turbidity (NTU) 1,2 (0,4 - 107) < 0,1
Color (mg/L Pt/Co) 4 (2,5 - 10) < 2,5
TOC (mg/L) 2,4 (1,6 – 4,1) 0,9 (0,7 - 1)
Total coliforms (n/100 mL) 100 (10 - 1000) 0
Fecal streptococci(n/100 mL) 16 (0 - 17) 0
Algae (nb/L) 0,5 106
(0,25 106 - 2 106) 0
Water Quality
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 63
Membrane processes Contents
� Membrane processes in drinking water treatment
� Design considerations
� Direct filtration
� Polishing: Clarification + UF
� Polishing: Clarification + GAC + O3 + UF
� Pretreatment for Reverse Osmosis
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 64
Membranes as polishing (clarification + UF)Example: Bexar Met WTP, USA (35 000 m 3/d)
coagulationfloculation
PAC
chlorination
Superpulsatorclarifier
7 x 48 modules of 55 m 2
PAC
Lagunes
recycling at inlet of clarifier
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 65
Membranes as polishing (clarification + UF)Example: Bexar Met WTP, USA (35 000 m 3/d)
min. - max. averageCoagulant dose(ferric chloride) 10 - 100 35 g/m3
Flow rate 50 - 140 95 l/h.m2 at 20°C
Backwash 30 – 90 min 40 min
Operating conditions
Water quality
Turbidity raw water 5 to > 1000clarified water 0,4 to 10filtered water 0,01 to 0,06
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 66
Membrane processes Contents
� Membrane processes in drinking water treatment
� Design considerations
� Direct filtration
� Polishing: Clarification + UF
� Polishing: Clarification + GAC + O3 + UF
� Pretreatment for Reverse Osmosis
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 67
Membranes as polishing (clarification+GAC+O 3+UF)Example: Vigneux WTP, France (55 000 m 3/d)
Set of 28 modules of individual surface area = 55m 2
PAC storage bin2 Ozonation U tubes
Parameters Units Mean Min-Max
Temperature °C 16 1 - 29.5
Turbidity ntu 16 5 – > 150
DOC mg/L 3.6 3.2 - 4.9
UV254 m-1 5.6 4.6 - 19
Surface Water, Seine River
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 68
Membranes as polishing (clarification+GAC+O 3+UF)Example: Vigneux WTP, France (55 000 m 3/d)
coagulationfloculation
PAC
chlorination
Pulsator& Superpulsator
clarifiers
GAC filters
8 x 28 modulesof 55 m 2
Cristal™ Process
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 69
with Cristal™ process
with Cristal™ process
with Cristal™ process
Membranes as polishing (clarification+GAC+O 3+UF)Impact of Cristal™ process on organic matter remov al
Coagulation -Floculation Settling GAC
Filtration
OzonationPAC
Chlorination
SeineRiver
Parameter Raw water Treated waterCOT 2,0 - 3,3 % removal 20-30% -
mg/l (2,0 - 2,6) -45 - 60% - 70 - 75%(0,9 - 1,6) - (0,5 - 0,9)
CODB 0,9 - 1,0 mg/l 0,5 - 0,8 -<0,2 - <0,2
UV254nm 4,5 - 6,5 % removal 30 - 40% 50 - 60%D-O (2,8 - 3,6) (1,9 - 2,7)
70% 80% 85 - 90%(1,4 - 1,8) (0,9 - 1,5) (0,4 - 0,7)
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with Cristal™ process
Membranes as polishing (clarification+GAC+O 3+UF)Impact of Cristal™ process on taste and odor remov al
Coagulation -Floculation Settling GAC
Filtration
OzonationPAC
Chlorination
SeineRiver
Parameter Raw water Treated waterLimitodor 5 (musty - silt – stagnant water) odor: 1 - 2
taste: 1 - 3Nonylphenols traces absenceDimethyl trisulfure 2 - 5 ng/l 1 - 3 ng/lMIB 2 - 6 ng/l 2 - 5 ng/l
odor: 1 - 2 0 chlorinetaste: 1 - 2 0 chlorineabsence absence1 - 3 ng/l absence2 - 5 ng/l < 1ng/l
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Conventionnel CristalO3 + CAG O3 + CAP/UF
CAPEX 8.2 M€ 11.7 M€- Ozone 4.4 M€ 4.4 M€- Polishing 3.8 M€ 7.3 M€*
OPEX 0.03 €/m3 0.06 €/m3
- Ozone 0.01 €/m3 0.02 €/m3
- Polishing 0.02 €/m3 0.4 €/m3**
* Racks UF : 21; Civil engineering : 9; Equipments : 18** Energy : 0.1; PAC : 0.13; Membrane : 0.16
Membranes as polishing (clarification+GAC+O 3+UF)Cost comparison
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 72
Membrane processes Contents
� Membrane processes in drinking water treatment
� Design considerations
� Direct filtration
� Polishing: Clarification + UF
� Polishing: Clarification + GAC + O3 + UF
� Pretreatment for Reverse Osmosis
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Membranes as pretreatment for ROExample: Heemskerk plant, Netherlands (70 000 m 3/d)
UF treatment objectivesDisinfectionRO pretreatment
RO treatment objectiveshardnesssalinitypesticidestaste and odornutrients bacteria
Ijssel Coagulation Sedimentation RSF UF RO Neutralizatio nLake
MEMBRANE FILTRATION PROCESSES
Microcoagulation
Improvement of UF competitiveness
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Background
1999microcoagulation
patent
2004Première
File
2004Air
backwash patent
End of 2005
Capex optimisation of UF solution
“Dead end” Microcoagulation
Improvement of cleaning procedures efficiency
� Water Backwash
� Flush
� Drain backwash
� Air backwash
Delivered to business
Equipment Process
09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 76
Microcoagulation processWithout
microcoagulation
1 mm
With microcoagulation
� Selected coagulant : FeCl3� Coagulant dosage : # 1 mg/L as FeCl 3
� Injection type : in line� Contact time & energy : preferably before feeding pump
Microcoagulation process and benefits
Agglomerate the diffused particules in raw water
In filtration : form a non uniform cake layer
Improve filtration flow
Reduction of membrane area required
Air backwash is necessary to prevent clogging and secure the UF system
Cleaning efficiency : optimise the removal of “cake”
� Water backwash� Flush� Drain backwash� Air backwash
Process Backwash
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09/10/2007 I WATER QUALITY DIVISION WATER TREATMENT MEMBRANE PROCESSES 77
Application fieldMicrocoagulation is not a continuous process well adapted to water with a large range of quality
variation : � Temperature ⇒ cold water < 15°C� Water quality ⇒ peak of dissolved NOM : abs UV 254 nm : 5-7 m-1
� Microcoagulation has no effect on settled water but may be slightly efficient on settled-filtrated water
� Warning ! ! ! : wash water contains Fe(OH) 3
Reduction of membrane area :
≥≥≥≥ 20%
Flux @ 6-15°C=
Flux @ 20°C
Lake waterSurface waterKarstic water
Sea water
Potential benefitFlux design Type of water
In case of water temperature > 15°C :
� less than 10% of operation time
� except DTG acceptance
� Design influenced by temperature
Reduction of membrane area :
≥≥≥≥ 20%
Design on “good” water quality
Lake waterSurface waterKarstic water
Potential benefitFlux design Type of water
� Design influenced by water quality (peak of dissolved NOM)
� drinking water criteria remains
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Seine river (pH = 7.6, turbidity = 5-10 NTU, COT = 2-3 mg/L, ab s UV 254 nm = 5-7 m-1)
Permeability
Flux
without
with
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Open intake seawater (pH = 8.1, turbidity = 0.5-1 NTU, COT = 0.3-0.5 mg/ L, UV 254 nm = 0.75-1 m -1, SDI = 13-24%/min)
Permeability
Flux
without
with
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Loue river (pH = 7.7, turbidity = 4-7 NTU, COT = 1.5-1.9 mg/L, abs UV 254 nm= 3-5 m-1)
Permeability
Flux
without
with