« What future for Membrane Processes in Water and Wastewater

Commentaires

Transcription

« What future for Membrane Processes in Water and Wastewater
Symposium sur l ’Eau ParisParis- Berlin:
23 octobre 2003
« What future for Membrane Processes in
Water and Wastewater Treatment ? »
Hervé BUISSON, Director, Anjou Recherche,
Maisons-Laffitte R&D Centre, France
ANJOU RECHERCHE
PLAN
1 Introduction
2 Present context and challenges
3 Current Developments
4 Conclusions
ANJOU RECHERCHE
|
From microfiltration to reverse osmosis
SCANNING ELECTRON MICROSCOPE
IONS
OPTICAL MICROSCOPE
VISIBLE TO NAKED EYE
MACRO MOLECULESMICRO PARTICLES
MOLECULES
MACRO PARTICLES
MICRON
Angström
Molecular
weight
Sugars
Viruses
Algae and protozoans
Dissolved salts
Bacteria
Pesticides
Colloids
Metal ions
Sands
Humic acids
REVERSE OSMOSIS
MICROFILTRATION
NANOFILTRATION
ULTRAFILTRATION
CONVENTIONAL FILTRATION
Note : 1 Angström = 10-10 meter = 10 -4 micron
|
Current Drinking Water Applications
Disinfection (crypto,
giardia)
Disinfection
+ Pesticides
Clarification
Polishing
NOM, BCOD,
pesticides,
softening)
X
Reverse
Osmosis
X
Nanofiltration
Microfiltration
Ultrafiltration
Desalination
X
X
(UF alone for virus)
(PAC hybrid)
X
X
X
Hybride Processes
(PAC, coagulants)
|
Current Wastewater Applications
Tertiary treatment
(for reuse)
Reverse
Osmosis
Enhanced Secondary
(reuse or sensitive
areas)
X
Nanofiltration
Microfiltration
Ultrafiltration
(as pre-treatment)
MBR
X
Industrial In-Plant
Industrial Process
Water
X
X
X
X
X
(UF more eg for O&G)
X
Hybride Processes
(PAC, coagulants)
X
X
X
Other
Industrial
Wastewater
Hybrid (MEUF, MEXT)
ED
X
ED/CDI
PLAN
1 Introduction
2 Present context and challenges
3 Current Developments
4 Conclusions
ANJOU RECHERCHE
|
Brief History of Membrane Technology for Water Applications...
1956 - early 1980s :
RO desalination, no commercial MF/UF for
drinking water
mid-1980 - early 1990s :Developement of Memcor (MF), Aquasource
(UF), clean waters & small capacities
(1993 - Milwaukee- cryptosporidium crisis)
mid-1990 - 2002:
Start of market growth, new competitors
(Zenon, Xflow,Hydranautics, Pall, Ionics)
with second generation membranes/modules)
Use on not so clean waters
Start of immersed MBR products
Now
Large plants > 200000m3/jour
Strong growth of RO desalination market
|
Early worldwide capacity increase
Cumulative capacities (MLD)
MF/UF/NF Worldwide Installed Capacities
1600
1400
1200
1000
800
MF+UF
NF/OI
600
Total
400
200
0
1991 1992 1993 1994 1995 1996 1997 1998 1999
|
Technico-Economical Hurdless to Membrane Success...
•
Membrane costs vs membrane life
uncertainty
•
Flux Decline (fouling, scaling,blocking,)
•
Need for proper process integration
•
Operation and maintenance issues
|
UN PROBLEME CLEF: la non maitrise du risque de colmatage
0,60
1,80
1,40
0,40
1,20
1,00
0,30
0,80
0,20
0,10
0,60
0,40
absorbance UV 254nm
de l'eau filtrée à traiter
0,20
0,00
01/06/99
02/06/99
ANJOU RECHERCHE
03/06/99
04/06/99
05/06/99
06/06/99
0,00
07/06/99
Indice UV 254 nm (abs/m)
Perméabilité relative Lp/Lp0
1,60
0,50
PLAN
1 Introduction
2 Present context and challenges
3 Current Developments
4 Conclusions
ANJOU RECHERCHE
|
From Good Membranes to Succesful Operations
Hydraulique
hydraulique
Procédé
conditions d'opération
Réalisation
stratégie de lavage
Intégration/couplage
pré-- traitement
pré
Fibres Creuses
(i-- e, e(i
e- i)
Spiralé
Plan
Module
ORGANIQUES
Polysulfone ,
PVDF,...
Membrane
INORGANIQUES
Oxydes Al ou Zr
Zeolites,...
Zeolites
,...
Ingénierie
Exploitation
Consignes et procédures
d ’exploitation
Gestion des « variabilités»
et des risques
|
Going back to basics: Hydraulics
Process scale
Pipe scale
Membrane scale
Fibre scale
|
Going back to basics: Water Chemistry
Étude de 2 configurations d ’un pilote CMF-S
TOC
175
150
Alimentation
14
Perméat
12
Rétrolavage
10
8
Configuration
purge à l ’égout
6
125
4
100
35
Prélévement analyses
40
45
50
55
60
65
70
75
time (min)
75
16
50
25
0
20/8/02 25/8/02 30/8/02
4/9/02
9/9/02 14/9/02 19/9/02 24/9/02 29/9/02 4/10/02 9/10/02
alimentation
14
Configuration
recirculation
permeat
12
TOC
-1 - 2
Perméabilité à 20°C (L.h
.m .bar-1)
Polysaccharides
16
10
8
6
4
PS associé aux pertes de performance
PS éliminé lors du nettoyage
35
40
45
50
55
time (min)
60
65
70
75
|
Going back to basics: Surface chemistry
? MEB avant / après
Extraction du dépôt sur
une membrane plane
Avant
extraction
A
Après
extraction
B
C
A: Membrane colmatée - B: Membrane après sonication
C: Membrane après sonication et raclage
|
Building upon standard processes knowhow
1. P-removal with MBR technology
2. Trace organics removal in MBR
“Development of optimised & cost effective
advanced P removal strategies using
immersed membranes”
“Contribution of membrane processes to the
removal of refractory COD and health related
organic pollutants from water cycles”
Combination of 3 processes are considered:
• Development of Bio-P in MBR
• Comparison with Co-P alone, or Co-P + Bio- P
• Evaluation of P-adsorption in MBR effluent on
activated media
Focus on:
• Endocrine disrupting compounds (EDCs)
• Pharmaceuticals (PhACs)
Configuration 1: Pre-denitrification
Configuration 2: Post- denitrification
=> post-DN for advanced N-removal in MBR
In view of water reuse (Berlin: short water cycle)
Ruhleben WWTP
|
IMF2: removal of micro-polluants in Biosep
Pre-DN MBR
Post-DN MBR
Elimination rate
0%
Polar compounds : PhACs
- Non biodegradable
- carbamacépine
- Partly biodegradable
- phenazone
50%
100%
Adsorbtion not improved
for polar compounds
- propyphenazone
-AAA
Better biodegradation
favoured by high SRT
Pre-DN > Post-DN?
-FAA
Not (less) polar compounds : EDCs
- Non biodegradable
- bisphenol-A
- Partly biodegradable
Adsorption improved for
non-polar compounds
- estrone
Improvement of
steroids removal
- estradiol
- ethynilestradiol
PhACs and EDCs analysed 2-6 times per month since Nov. 2001
on mean 24-h samples taken « in switch » (with plants HRT)
statistical analyses possible (6 à 12 bi-monthly values)
|
Focussing on global solutions rather than membranes
Pre -Treatment
lime
CMF-S
coagulant
Ozone & BAC Filtration
Raw Water Storage
ozone
8
8
CO 2
chlorine
ammonia
lime
Bendigo
Consumers
Post Treatment & Storage
Waste Residuals
|
Key to sucess: Operating expertise and know-how
Exploitation
conditions d ’exploitation
Outils d’aide à la conduite
gestion des « variabilités »
|
KEY OPERATING LESSONS
•
Adequate training and operating procedures are essential (key
possible failures, cleaning, recommended first actions)
•
Need for operator-support tools to help develop a continuous
diagnostic of the hydraulics/behaviour of the plant and
anticipate problems ASAP (smart but robust interface between
supervision and operators)
•
Access to strong chemical/biochemical analytical backup
possible fouling/cleaning diagnostic (some applications are
tough, with negative ROIs!)
•
Integration of Membrane operations into global water and
waste operating scheme (sludge disposal, pre-treatment,
pollution prevention plans as well as possible process water
segregation)
PLAN
1 Introduction
2 Present context and challenges
3 Current Developments
4 Conclusions
ANJOU RECHERCHE
|
CONCLUSIONS:
?
Membranes and Membrane Processes are not Magical!!
Their implementation at very large scale still represents
an unacceptable level of technico-economical risk today
for some applications.
?
The challenge : Find the right place for these tools into
our toolbox, develop the right process trains for each
application, develop robust adapted operating
practices, minimizing technical anf financial risks
?
Membranes need to be forgotten, or seen as only part of
the solution for membrane processes to gain full
potential in Water and Wastewater Treatment
ANJOU RECHERCHE

Documents pareils