Recent Trends in Membrane Technology for
Water quality management
Prof. (Dr.) P. K. Tewari
President Indian Desalination Association
Professor Homi Bhabha national Institute
Head Desalination Division
Bhabha Atomic Research Centre
Trombay Mumbai (India)
January 20,2011 Delhi
Access to water ≠ Safe drinking water
Water Quality Problem
No.of habitations
Number of Habitations affected by Contaminants in India
140,000
120,000
100,000
80,000
60,000
40,000
20,000
0
Source: DDWS
Science and technology for water quality
management
Disinfection
Decontamination
Clean water
Desalination
Re-use and reclamation
Shannon etal. Nature 452(2009)301-310.
URBAN SECTOR
(Large size requirement MLD)
RURAL SECTOR
(Community size desalination/ water
purification systems KLD)
DOMESTIC SECTOR
(Point of use technology LPD)
INDUSTRIAL SECTOR (Waste heat utilization/
water recycling & reuse KLD to MLD)
DISASTER MANAGEMENT
(Extreme field conditions KLD)
Coimbatore February 2009
Membrane Technology
Pressure Driven Membrane Processes
Salient features of the membranes
Parameter
UF
NF
RO
Pore size
1-200 nm
1-5 nm
0.1-1 nm
Operating
pressure
1-4 bar
7-15 bar
>15 bar
Flux
2000-5000
LMD
>700 LMD
400-800
LMD
Energy
requirements
0.03 KWeh
4-5 KWeh
5-9 KWeh
Suitable for
Complex
ions/molecules
MW>600
Ionic
species,
bivalents
Monovalent
ionic
species
Selection of
Polymer
Preparation
of
Membrane
Characterization
Application
Diagnostics
CHALLENGES
• High efficiency
membrane
•Membrane life
•Membrane flux
•Fouling & compaction
resistant
WATER PURIFICATION
Ultra-Filtration (UF) Membarane for Domestic Water
Purification
No suspended solids
No Bacteria (Inactive, dead or decayed)
Very Compact
UF membrane candle
Small inexpensive device
Housing
No need of electricity
No need of Chemicals
Highly resistant towards chemicals
No loss of water, (dead end operation)
UF Membrane device
for domestic water
purification
Commercialized On-line Domestic Water Purifier Produced &
Marketed by BARC’s Licensees
No of licensees: 21
Rural Adaptation of BARC developed Membrane
Based water Purification Technology
Contaminated
water
Ultra-Filtration (UF) based domestic and community level
water purification technologies
 Removal of bacteria and virus from the contaminated water
Works without electricity.
Domestic Water
Purifier
pure
water
BARC Developed Membrane based Next Generation Water Purification
Devices
Arsenic removal (product water <10 ppb as per WHO standard)
Iron removal (product water <0.3 ppm as per WHO standard)
Fluoride removal (product water <1 ppm as per WHO standard)
UF
Module Capacity: 5 KLD
Role of BARC in Desalination & water Purification-Present CapabilitiesSolar Energy Driven Desalination & Water Purification
Solar Energy Driven Desalination & Water Purification Facilities at
Trombay
RO Capacity: 2000 LPD*
LPD*: Litres Per Day
UF Capacity
2400 LPD
RO Capacity
240 LPD
Solar-Thermal
1000 LPD
DESALINATION
Trailor Mounted Brackish Water RO Desalination Plants
Present Capabilities in Community size (KLD)- BARC
DG
UF
RO
Trailor Mounted RO Developed by BARC
RO Plant for Sea water Desalination at Kalpakkam BARC
(Capacity: 1.8 MLD)
PLANT
CHARACTERISTICS:
•Product Quality:
As per WHO
•Higher membrane
flux hence more
production
•Energy Recovery
•Less pretreatment
BACKWASHABLE SPIRAL WOUND ULTRAFILTRATION
ELEMENT
•
•
•
•
•
•
•
SALIENT FEATURES
Physical elimination of Suspended solids, Micro-organisms,
Ensures continuous operation, Low foot print, Stable flux,
Colloidal species, Turbidity
Stable output quality
Useful as community water purifier
Useful as pretreatment for desalination
BACKWASHABLE UF ELEMENT
IN OPERATION
SPECIFICATIONS
• Operating pressure 2-3 Kg/cm2 (g)
• Backwashing pressure upto 2.0 Kg/cm2(g)
• Polysulphone/ Polyether sulphone Ultrafiltration membrane
• Cross flow mode of operation for higher NTU feed
• Dead-end mode operation for feed quality upto 10 NTU
• Membrane flux of 1000 lmd/bar
• Backwashing by filtrate / pure service water
Technology transferred to 3 parties
Development of Barge Mounted RO Plant for Drinking Water from
Sea Water in coastal areas
Capacity
50 cubic meter/day
Process
UF pretreatment followed by RO
UF Details
6 Nos. of UF HF cartridges
Recovery 75% (net)
Feed flow 12 cubic meter/h at 2 bar
RO module
6 Nos. of 8040 SWRO spiral wound
membrane elements in 3 Nos. of 2
elements FRP pressure vessels in
series, Recovery 25%.
HP pump set
9 cubic meter/h, 50 bar
HP engine
20 kVA diesel engine
Fuel tank capacity
2.5 kL (15 days storage @ 7 lph
consumption), 1.4 m dia x 1.65 m H
Some of Membrane based Seawater Desalination Plants
in India
S.
Place
No.
1. NDDP, Kalpakkam
6.
7.
8.
TWAD, Chennai
NPCIL, Kudankulam
CMWSSB, Chennai
9.
CPCL, Chennai
Capacity Process Supplied/ Installed
(MLD)
by
6.3
Hybrid BARC (India)
(MSFRO)
3.8
SWRO
BHEL (India)
1.2
SWRO
Tata Proj/ Doshi Ion
100
SWRO
IVRCL/
BEFESA
(Spain)
26
SWRO
Ion Exchange (India)
SWRO Desalination Plant at Minjur Chennai (India) set up by
IVRCL & BEFESA (Spain) on DBOOT Basis
Capacity: 100 MLD
Source: CMWSSB
Nuclear Energy Driven Desalination Plant based on Hybrid MSF-RO
Technology at Kalpakkam
Total capacity (MLD): 6.3
Multi-Stage Flash (MSF)
Capacity (MLD): 4.5
Product water quality (ppm): 2
(distilled quality, good for high
end industrial use)
Reverse Osmosis (RO)
Capacity (MLD): 1.8
Product water quality (ppm): 250
(fit for human consumption)
MLD: Million Litres/Day
WASTE WATER RECOVERY &
RECYCLE
Industrial Waste Water Management (any capacity KLD to MLD)
CONVENTIONAL WASTE WATER TREATMENT
Raw
Water
Water Treatment
Plant
Source
Reduction
Treated
Water
Process
Effluent
Effluent Treatment
Plant
Discharge
WASTE WATER MANAGEMENT USING MEMBRANE PROCESSES
Product
Recovery
Recovered Product
Raw
Water Treatment
Plant
Water
Treated
Water
Process
Recycled Water
Effluent
Product
Recovery Plant (NF)
Partially
treated
effluent
Water Recovery &
Recycle Plant (RO)
Water Reuse
Minimal Discharge
Integrated Solution
Waste
Minimisation
Emerging Trends in Membrane
Technology
Charged membranes
Cl-
Na+
Ca++
SO4--
Cl+
+
+
+
+
+
+
+
+
+
+
Positively charged membrane
Quaternary ammonium
groups like -N+ (CH3)4 Clcontribute to the fixed
positive charge of the
membrane
SO4--
Na+
Ca++
- - - - - - - - - - -
Negatively charged membrane
Negatively charged groups like
SO3H+, COOH groups
contribute to the negative
charge of the membranes
Nano-materials of Interest for Water Purification
Nano-material
Contaminants Removal
Metal nanoparticles & Bimetallic
Organic & inorganic pollutants
nanoparticles (effective redox media)
Metal oxide like TiO2 (effective
photocatayst)
Organics like Chloro-alkanes and inorganic
pollutants like heavy metals
Metal oxides like MgO and Ag
nanoparticles
Bacteria removal
Carbon Nanotubes (Nanosorbents)
Heavy metals like Pb, Cd, Cu etc.; organics
like dioxin, anions like arsenate, fluoride
etc ; bacteria like E. Coli and polio virus
Nanotube/ nanoparticle embedded
membrane (Nanocomposite
membrane)
Removal of wide range of contaminants
from water with high flux, high selectivity,
less fouling characteristics
Activated carbon fibers
(nanosorbents)
Organics like benzene, toulene etc.
Selected nanomaterials currently being evaluated
as functional materials for water purification
Dendrimer (repeatedly branched
polymeric species)
Carbon Nano-Tube
Zeolite (microporous
aluminosilicate materials)
Metal Oxide
Nanotechnology in Water Purification
Bacteria removal
Anions removal (Arsenite, Arsenate etc.)
Organic contaminants removal
Heavy Metals Removal (Lead, Cadmium etc.)
Carbon Nano-Tubes (CNT)
Graphitic sheets rolled into seamless
tubes have diameters ranging from
about a nanometer to tens of nanometers
with lengths up to centimeters have
unique electrical, thermal,
hydrodynamic and mechanical
properties
SWNT-A single graphite
sheet rolled
1. Soumitra Kar, R.C. Bindal, S. Prabhakar, P.K. Tewari,
'Potential of Carbon Nano-Tubes in Water Purification: an
Approach towards Development of an Integrated
Membrane System', International J. of Nuclear
Desalination, Vol.3, No.2, 2008, pp 143-150
2. K. Dasgupta, Soumitra Kar, Ramani Venugopal, R.C.
Bindal, S. Prabhakar, P.K. Tewari, Self-standing Geometry
of Aligned Carbon Nano-Tubes with High Surface Area,
MWNT-Multiple graphitic sheets
Materials Letters, Vol. 62, 2008 pp 1989-1992
rolled
CNT membrane fabrication steps
Conformal encapsulation of
as-grown aligned CNTs
With Polymer/Ceramic
Challenge is to have 12
orders of magnitude of
aligned CNTs per sq. cm
Opening of CNT tips
Using plasma
oxidation or acid
treatment
Removal of excess
material above the CNT
array and metallic
nanoparticles at the
back. HF acid etch to
remove membrane from
substrate
Hinds, B.J., et al. (2004) Science, Vol. 303, p.62.
Nanocomposite Membranes in Water Purifications
Applied pressure: 1.24
MPa
Feed concentration:
2000 ppm
Effect of zeolite loading on separation performance of
synthesized TFC and TFN membranes
Journal of Membrane Science, 294, 2007, 1
Challenges & Opportunities in CNT-based Membrane
 If carbon nanotube–based membranes can be scaled up and
made to exclude salts— it could enable desalination facilities to
sharply reduce the amount of energy required to purify water
The CNT based membrane fabrication (scaling up to large size),
could be useful industrially for chemical separations
CNT/ceramic composites (instead of CNT-Polymer composites) can
be used in the field of high-temperature applications
Challenges & Opportunities in CNT-based Membrane
Nanostructured materials are of tremendous interest, from
both a fundamental and applied perspective because of:
Exceptional thermal and mechanical stability
High surface area
Reusability with full filtering efficiency regained
Chemical functionalization of the surfaces
•Nanotechnology is an emerging field with great opportunities.
•Commercialization of R&D work and product development is yet
to pickup.
•Synergy among different R&D groups and industries is needed.
•It is estimated that nanotechnology has potential to create a
trillion dollar industry by 2030.
Thanks
Production of the macro architecture of aligned
nanotubes for use in filtration applications
a. Spray Pyrolysis of Benzene-Ferrocene mixture
b. Macro tube grown composed of aligned CNTs
c. SEM cross section of Macrotube
Srivastava, A., et al. (2004) Nature Materials, Vol. 3, p.610.