Recent Trends in Membrane Technology for Water quality management

Prof. (Dr.) P. K. TewariPresident Indian Desalination Association Professor Homi Bhabha national Institute

Head Desalination DivisionBhabha Atomic Research Centre

Trombay Mumbai (India)

January 20,2011 Delhi

Access to water ≠ Safe drinking water

0

20,00040,000

60,000

80,000

100,000120,000

140,000

Fluorid

e

Arsen

ic

Salinit

yIro

n

Mult

iple

No

.of

hab

itat

ion

s

Source: DDWS

Water Quality Problem

Number of Habitations affected by Contaminants in India

Clean water

Disinfection Decontamination

Re-use and reclamationDesalination

Shannon etal. Nature 452(2009)301-310.

Science and technology for water quality management

Coimbatore February 2009

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)

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

CHALLENGES• High efficiency membrane•Membrane life•Membrane flux•Fouling & compaction resistant

Selection of Polymer

Preparationof

MembraneCharacterization Application Diagnostics

WATER PURIFICATION

UF membrane candleHousing

No suspended solids

No Bacteria (Inactive, dead or decayed)

Very Compact

Small inexpensive device

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

Ultra-Filtration (UF) Membarane for Domestic Water Purification

Commercialized On-line Domestic Water Purifier Produced & Marketed by BARC’s Licensees

No of licensees: 21

Domestic Water Purifier

Contaminated water

pure water

Rural Adaptation of BARC developed Membrane Based water Purification Technology

Ultra-Filtration (UF) based domestic and community level water purification technologies

Removal of bacteria and virus from the contaminated water

Works without electricity.

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)

Module Capacity: 5 KLD

UF

Role of BARC in Desalination & water Purification-Present Capabilities-Solar Energy Driven Desalination & Water Purification

Solar Energy Driven Desalination & Water Purification Facilities at Trombay

RO Capacity: 2000 LPD* UF Capacity 2400 LPD

RO Capacity 240 LPD

Solar-Thermal 1000 LPD

LPD*: Litres Per Day

DESALINATION

DG UF RO Trailor Mounted RO Developed by BARC

Trailor Mounted Brackish Water RO Desalination PlantsPresent Capabilities in Community size (KLD)- BARC

PLANT CHARACTERISTICS:•Product Quality: As per WHO•Higher membrane flux hence more production•Energy Recovery•Less pretreatment

RO Plant for Sea water Desalination at Kalpakkam BARC (Capacity: 1.8 MLD)

• 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

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

BACKWASHABLE UF ELEMENTIN OPERATION

BACKWASHABLE SPIRAL WOUND ULTRAFILTRATION ELEMENT

Technology transferred to 3 parties

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

Development of Barge Mounted RO Plant for Drinking Water from Sea Water in coastal areas

S. No.

Place Capacity (MLD)

Process Supplied/ Installed by

1. NDDP, Kalpakkam 6.3 Hybrid (MSF-RO)

BARC (India)

6. TWAD, Chennai 3.8 SWRO BHEL (India)7. NPCIL, Kudankulam 1.2 SWRO Tata Proj/ Doshi Ion 8. CMWSSB, Chennai 100 SWRO IVRCL/ BEFESA

(Spain)9. CPCL, Chennai 26 SWRO Ion Exchange (India)

Some of Membrane based Seawater Desalination Plants in 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

Integrated Solution

CONVENTIONAL WASTE WATER TREATMENT

ProcessRaw

WaterWater Treatment

Plant

Treated

WaterEffluent Treatment

PlantEffluent Discharge

WASTE WATER MANAGEMENT USING MEMBRANE PROCESSES

ProcessRaw

WaterWater Treatment

PlantTreated

Water

ProductRecovery Plant (NF)

Effluent

Partiallytreatedeffluent

Water Recovery &

Recycle Plant (RO)

Recycled Water

Recovered Product

Minimal Discharge

Source Reduction Product

Recovery

Water ReuseWaste

Minimisation

Industrial Waste Water Management (any capacity KLD to MLD)

Emerging Trends in Membrane Technology

Charged membranes

Positively charged membrane

+ + + + +

++++++

Na+

Ca++

SO4--Cl-

Quaternary ammonium groups like -N+ (CH3)4 Cl-

contribute to the fixed positive charge of the membrane

-- - - - -- - - - - -

Cl-Na+

Ca++

SO4--

Negatively charged groups like SO3H+, COOH groups contribute to the negative charge of the membranes

Negatively charged membrane

Nano-materialNano-material Contaminants RemovalContaminants Removal

Metal nanoparticles & Bimetallic Metal nanoparticles & Bimetallic nanoparticles (nanoparticles (effective redox mediaeffective redox media))

Organic & inorganic pollutantsOrganic & inorganic pollutants

Metal oxide like TiO2 (effective Metal oxide like TiO2 (effective photocataystphotocatayst) )

Organics like Chloro-alkanes and Organics like Chloro-alkanes and inorganic pollutants like heavy metals inorganic pollutants like heavy metals

Metal oxides like MgO and Ag Metal oxides like MgO and Ag nanoparticlesnanoparticles

Bacteria removalBacteria removal

Carbon Nanotubes (Carbon Nanotubes (NanosorbentsNanosorbents)) Heavy metals like Pb, Cd, Cu etc.; organics Heavy metals like Pb, Cd, Cu etc.; organics like dioxin, anions like arsenate, fluoride like dioxin, anions like arsenate, fluoride etc ; bacteria like E. Coli and polio virusetc ; bacteria like E. Coli and polio virus

Nanotube/ nanoparticle embedded Nanotube/ nanoparticle embedded membrane (membrane (Nanocomposite Nanocomposite membranemembrane))

Removal of wide range of contaminants Removal of wide range of contaminants from water with high flux, high from water with high flux, high selectivity, less fouling characteristicsselectivity, less fouling characteristics

Activated carbon fibers Activated carbon fibers ((nanosorbents)nanosorbents)

Organics like benzene, toulene etc.Organics like benzene, toulene etc.

Nano-materials of Interest for Water Purification

Selected nanomaterials currently being evaluated as functional materials for water purification

Dendrimer (repeatedly branched polymeric species)

Zeolite (microporous aluminosilicate materials)

Carbon Nano-Tube 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 Graphitic sheets rolled into seamless tubes have diameters ranging from tubes have diameters ranging from about a nanometer to tens of nanometers about a nanometer to tens of nanometers with lengths up to centimeters have with lengths up to centimeters have unique electrical, thermal, unique electrical, thermal, hydrodynamic and mechanicalhydrodynamic and mechanical propertiesproperties

SWNT-A single graphite sheet rolled

MWNT-Multiple graphitic sheets 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, Materials Letters, Vol. 62, 2008 pp 1989-1992

Conformal encapsulation of as-grown aligned CNTs With Polymer/Ceramic

Removal of excess material above the CNT array and metallic nanoparticles at the back. HF acid etch to remove membrane from substrate Opening of CNT tips

Using plasma oxidation or acid treatment

CNT membrane fabrication steps

Hinds, B.J., et al. (2004) Science, Vol. 303, p.62.

Challenge is to have 12 orders of magnitude of aligned CNTs per sq. cm

Nanocomposite Membranes in Water Purifications

Effect of zeolite loading on separation performance of synthesized TFC and TFN membranes

Journal of Membrane Science, 294, 2007, 1

Applied pressure: 1.24 MPa

Feed concentration: 2000 ppm

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 stabilityHigh surface areaReusability with full filtering efficiency regainedChemical 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.

Challenges & Opportunities in CNT-based Membrane

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 CNTsc. SEM cross section of Macrotube

Srivastava, A., et al. (2004) Nature Materials, Vol. 3, p.610.