IWA conference in Beijing Sept 06 |
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Membrane Science Technology Symposium NTU April 06 |
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IDA world congress Sept 05 |
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GrahamTek Singapore provides the design, supply , fabrication
and installation of complete RO systems and skids and warrants
their performance . |
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GrahamTek RO membranes:
GrahamTek 16 inch RO membranes are manufactured
by reputable membrane suppliers such as Hydranautics and
SAEHAN who manufacturers the membranes for GrahamTek under
licensing arrangements.
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large diameter membrane loading device:
For loading of the large diameter elements
into the 16 inch diameter vessels, GrahamTek has designed
a membrane loader device which is mounted on top of a scissors
lift device. This device allows loading of membranes into
vessels of various heights in an RO skid.
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R&D
tasks and panel of experts
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The GrahamTek Scientific
Program
In a meeting held in Singapore in April
2006, the GrahamTek Scientific Program was initiated. The
objective of the Program is not to prove that GrahamTek
technology works, but, a) to demonstrate conclusively why
it works so well; and b) simultaneously explore optimizing
the various elements of the technology. The agenda of the
meeting was as follows:
Mr. Bjarne Nicolaisen, Consultant to GrahamTek
1. Overview of GrahamTek Technology
2. Critical Flux of Conventional 8" RO Membranes versus
16" GrahamTek RO Membranes
Professor Harvey Winters, Fairleigh Dickinson University,
USA
1. Overview of Biofouling (VBNC)
2. Critical Flux and Flow Distribution
3. Calculation of Seawater RO Critical Flux for VBNC
4. Specific Flux of 16" GrahamTek RO Membranes versus
Conventional 8" RO Membranes
5. Effect of Flow Distribution on Critical Flux
Professor Hans Coster, University of New South Wales, Australia
1. Effect of EMF on Bacteria and Particles
Professor Tony Fane, University of New South Wales and
Nanyang Technical University, Singapore
1. Critical Flux of Bacteria - Effect of Aggregation and
Bubbles
Professor Greg Leslie- University of New South Wales, Australia
1. Possible Effect of EMF on Scale Formation
Professor Adrian Law, Nanyang Technical University, Singapore
1. Measurement of Bubbles Formed by a Novel Flow Distributor
Professor How Yong Ng, National University of Singapore,
Singapore
1. Computational Fluid Dynamics (CFD) on a Novel Flow Distributor
2. Reverse Osmosis (RO) Process Modeling, 16" GrahamTek
versus 8" RO
3. Pilot Studies of 8" Conventional and 16" GrahamTek
RO
An update review meeting followed in Singapore in November
2006, when intermediate research results were reported.
The Program is ongoing and expected to continue into 2007,
with the final reports being presented in the second quarter.
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Professor
A G ( Tony ) Fane
UNESCO Centre for Membrane Science & Technology,
University of New South Wales,
Sydney NSW 2052.
Website : www.membrane.unsw.edu.au
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(i) DOTM Technique
used for critical flux analysis:
Li, H., Fane, A. G., Coster, H. G. L. and Vigneswaran, S.,
Direct observation of particle deposition on the membrane
surface during crossflow microfiltration, J. Memb. Sci.,
149 (I) p 83-09 (1998).
Zhang,Y.P., Fane,A.G. and Law, A.W.K., Critical flux and
particle deposition of bidisperse suspensions during crossflow
microfiltration, J.Memb.Sci. 282 (1-2) 189-197 (2006).
(ii) Tracer technique used for
RO fouling and polarisation assessment,
Chong, T.H., Wong,F.S. and Fane, A.G., Fouling in reverse
osmosis: detection
by noninvasive techniques, Desalination, (in press) Chong,T.H.,
Wong,F.S.and Fane,A.G., Enhanced concentration polarization
by unstirred fouling layers in RO: detection by stimulus-response
technique. J.Memb.Sci. (in press)
(iii) Title submitted to European
Desalination Society Conference
(Thessalonika, Greece, April 2007)
IMPLICATIONS OF ENHANCING CRITICAL FLUX OF PARTICULATES
BY AC FIELDS IN RO DESALINATION AND RECLAMATION
Zhang,Y.P., Chong, T.H., Fane,A.G.,
Law,A., Coster,H.G.L. and Winters,H.
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GT Research Topics Overview
A G Fane et al.
Objectives
This project has the following objectives
(i) to gain a better understanding of the underlying mechanisms
involved in the EMF effect in RO desalting applications;
(ii) to establish the conditions where the novel EMF effect
minimizes the fouling of membranes, particularly in RO desalting
applications, in terms of,
- inorganic scale formation,
- particulate fouling,
- bacterial deposition and biofilm formation.
(iii) to examine the effect of the IFD flow distributor
on downstream hydrodynamics, and particularly on the formation
of microbubbles;
(iv) to examine alternative flow distributor 'geometries'
in terms of downstream hydrodynamics;
(v) to establish the effect of microbubbles on the fouling
of membranes, particularly in RO desalting applications,
in terms of,
- particulate fouling,
- bacterial deposition and biofilm formation,
- (and possibly, inorganic scale formation).
Project tasks
The project will involve a series of well-controlled experiments
in laboratory scale membrane devices, supported by leading
edge monitoring techniques. The laboratory equipment and
monitoring techniques are already established in our laboratories
at the UNESCO Centre at UNSW in Sydney and through the Temasek
Professor Programme at NTU in Singapore. The project has
the following tasks:
Task 1. Effect of EMF on bacterial /particle
aggregation and implications for RO
(A review by Professor Hans Coster and Prof Tony Fane)
Task 2 Effect of EMF on scale formation
( A Prof Greg Leslie, Prof T Fane and Dr Nik Zwaneveld)
Task 3. Effect of EMF on Critical Flux
of particulates, by DOTM
Effect of small bubbles on critical flux of particulates,
by DOTM
( A Prof Adrian Law, Prof T Fane and Yanpeng Zhang)
Task 4. Effect of EMF (and bubbles) on
biofilm and particulate fouling in RO tester
( Prof T Fane and Tzyy Chong)
Task 5 Assessment of the formation of microbubbles
by the IFD flow distributor
( A Prof Adrian Law and Dr Filicia Wicaksana)
A.G.Fane
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Professor
Ng How Yong
National University of Singapore
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GrahamTek -NUS Research
Project Overview
How Yong Ng et al.
Objective
The objective of this Project is to scientifically and/or
technically explain the reasons why the GrahamTek RO System
using large-diameter 16-inch elements with the GrahamTek
patented Flow Distributor and electro-magnetic force is
able to achieve a higher performance than the conventional
16-inch x 40 inch RO System utilizing the standard anti-telescoping
device (ATD); and
Scope
The scope of this study is summarized as follows:
1. To model the hydraulic flow of the GrahmTek patented
Flow Distributor using computational fluid dynamics (CFD)
analysis and to investigate the transport characteristics
in the RO system with and without the GrahamTek patented
Flow Distributor. The results will be used for optimizing
the performance of the 16-inch and 8-inch RO systems.
2. To conduct experiments using laboratory-scale RO systems
for simulating long channel of RO filtration in the presence
and absence of electro-magnetic field. Results obtained
from the laboratory-scale studies will be used for calibrating
the computer model and verifying its validity and enhance
accuracy.
Project tasks
The project will comprise of two (2) parts:
Part 1 - Modeling and Mechanistic Studies
Modeling of hydraulic flow of the GrahamTek patented Flow
Distributor using CFD will be carried out. Based on the
CFD analysis, flow characteristics after the ATD or GrahamTek
Flow Distributor will be determined. The flow parameters
obtained will be used in modeling for predicting the RO
membrane flux.
Studies on the transport mechanisms using RO filtration
models will be carried out to explain the enhancement of
performance by the Flow Distributor compared with the standard
ATD in both large-diameter (16 x 40-inch) and the 8 x 40-inch
RO systems.
Part 2 - Laboratory Studies
Laboratory studies would be conducted using small and long
RO filtration setups with different flow characteristics.
The purpose of this part of the study is to investigate
the impact of the electro-magnetic filed, inlet flow characteristics,
channel characteristics and spacers on RO seperation performance.
The data will be used for calibration of Part 1 studies.
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GrahamTek related research:
The dynamics of particles in AC electric fields, including
fields induced by
alternating magnetic fields. This includes theoretical and
experimental
studies on the translation, rotation and aggregation of particles
in AC
fields. Studies include the role and application of the electro-mechanics
of particles in particle aggregation, cross-flow filtration,
electr-disinfection and the manipulation of living cells.
Selected papers:
Mahaworasilpa, T. L., H. G. L. Coster and E. P. George (1994).
"Forces on
biological cells due to applied alternating (AC) electric
fields. I.
Dielectrophoresis." Biochim. Biophys. Acta 1193: 118-126.
Chilcott, T. C., H. G. L. Coster and E. P. George (1995).
"A novel method
for the characterisation of the double fixed charge (bipolar)
membrane using
impedance spectroscopy." J. Membrane Sci. 108: 185-197
Mahaworasilpa, T. L., H. G. L. Coster and E. P. George
(1996). "Forces on
biological cells due to applied alternating (AC) electric
fields. II.
Electro-rotation." Biochim. Biophys. Acta 1281: 5-14.
Coster, H. G. L. and T. C. Chilcott (1999). "The characterisation
of
membranes and membrane processes using impedance spectroscopy."
Electrochemistry of membranes : T.S. Sorensen : ,Marcel
Dekker, New York
Gaedt, L., Chilcott, T. C., Chan, M., Nantawisarakul, T.,
Fane, A. G. and
Coster, H. G. L. (2002) "Electrical impedance spectroscopy
characterisation
of conducting membranes. II Experimental". J. Membr.
Sci. 195: 169-180
Li, H., Fane, A.G., Coster, H.G.L., Vigneswaran, S. (2003)
"Observation of
deposition and removal behaviour of submicron bacteria on
the membrane
surface during crossflow microfiltration. J.Memb. Sci 217:
29-41.
Park, J.C., Chilcott, T.C., Coster, Hl.G.L.,
Moon, S.-H. (2005)
"Characterization of BSA-fouling of ion-exchange membrane
systems using a
subtraction technique for lumped admittance data."
J.Memb.Sci 246:137-144
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Professor
Harvey Winters
Professor Emeritus in School of Natural Sciences
Fairleigh Dickinson University, Teaneck,
New Jersey, USA
Principal Investigator of GrahamTek Related Research
Website : www.fdu.edu
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Dr. Winters is currently Professor Emeritus
in School Of Natural Sciences at Fairleigh Dickinson University,
Teaneck, New Jersey USA. He obtained his B.S. and M.S. degrees
from Department of Biological Sciences, Fairleigh Dickinson
University, Teaneck, New Jersey and his Ph.D. in Chemical
Biology from Columbia University, New York, New York in
1970.
His current studies is focused on the role of VBNC bacteria
in microbial fouling of Reverse Osmosis membranes and the
role of crossflow velocity in affecting critical flux of
VBNC bacteria in Reverse Osmosis.
As Principal Investigator of GrahamTek
research, his role is to coordinate his research with that
of Professors Coster, Fane, Leslie, Law and Ng in explaining
how the flow distributor and EMF allow the GrahamTek 16”
membrane achieve very high flux rates without incurring
membrane fouling. The research is focused on
(1) the physics of EMF and how EMF affects critical flux
and inhibits scale formation,
(2) the role of EMF on biofilm formation,
(3) the assessment of formation of microbubbles by the flow
distributor,
(4) the effect of EMF on critical flux,
(5) modeling of hydraulic flow of GrahamTek flow distributor
using CFD and flow characteristics after ATD and flow distributor
(6) the role of crossflow velocity in affecting critical
flux.
Selected papers:
Ng, H.Y., and Winters, H. “A Novel 16 Inch RO System
for Water Reuse and Desalination”. Israel Desalination
Society, Innovations and Applications of seawater and marginal
Water Desalination, Haifa, Israel, 19-20 December 2006.
Winters, H. “Use of a Novel Flow Distributor and EMF
in Seawater Reverse Osmosis to Prevent microbial Fouling
of Membranes”. Membrane Science & Technology 2006
Symposium, Singapore, 27-28 April 2006.
Winters, H. “Microfouling of Cartridge
Filters and RO Membranes: Mechanisms and Effects”.
IDA World Congress on Desalination and Water Reuse, Singapore,
11-15 September 2006.
Winters, H. Critical Flux and Fouling of
RO Membranes”. Keynote Speaker @ Euromembrane 2000,
Judean Hills, Israel, 24-27 September 2000.
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Dr Law is currently an Associate Professor
in the School of Civil and Environmental Engineering in
Nanyang Technological University (NTU), and also the Assistant
Director of the Singapore Stanford Programme. He obtained
his B.Eng. degree from the Department of Civil and Structural
Engineering, University of Hong Kong, and later M. Sc. and
Ph.D. from the Department of Civil Engineering, University
of California at Berkeley.
After graduate studies, he worked as a
hydraulic engineer in the industry, first with Hydro-Research
Science at Santa Clara, California and then with Bechtel
Corporation at San Francisco, California.
From 1995 he has been teaching environmental
hydraulics and coastal engineering to civil and environmental
engineering students in NTU.
His current research interest is in the
area of environmental fluid mechanics, with special emphasis
on membrane processes, and wastewater disposal and impact
in the coastal environment.
He was the recipient of the American Society
of Civil Engineering Wesley W. Horner Award in 2000, as
well as the Bechtel Corporation Outstanding Technical Paper
Award in 1999 and 2000.
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Chong
Tzyy Haur
B. Eng. degree in Chemical Engineering from The
University of New South Wales, Australia
PhD research student at Nanyang Technological
University, Singapore |
Chong Tzyy Haur obtained his B. Eng. degree
in Chemical Engineering from The University of New South
Wales, Australia. He is currently a PhD research student
at Nanyang Technological University, Singapore.
His research topic is ‘Reverse Osmosis
Desalination and Reclamation – Control of Fouling’.
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| In a meeting
held in Singapore in April 2006, the GrahamTek Scientific
Program was initiated. The objective of the Program is not
to prove that GrahamTek technology works, but,
a) to demonstrate conclusively why it works so well;
b) simultaneously explore optimizing the various elements
of the technology. |
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Professor
A G ( Tony ) Fane
UNESCO Centre for Membrane Science & Technology,
University of New South Wales,
Sydney NSW 2052.
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Professor
Ng How Yong
National University of Singapore
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Professor
Hans G. L. Coster
FTSE Director, Biophysics and Bioengineering
School of Chemical and Biomolecular Engineering, University
of Sydney
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Professor
Harvey Winters
Professor Emeritus in School of Natural Sciences
Fairleigh Dickinson University, Teaneck, New Jersey,
USA
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Dr Adrian
Law Wing Keung
School of Civil and Environmental Engineering in Nanyang
Technological University
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Chong Tzyy
Haur
PhD research student at Nanyang Technological University,
Singapore
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The GrahamTek 16 inch RO was successfully piloted over 20
months at the Bedok NEWater Factory since Dec 04 . This report
can be downloaded here. |
The
report on this pilot test can be downloaded here
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The Super-Flux Pilot Plant was commissioned on the 10 Aug
06 and 12 nos. Hydranautics brackish elements fitted with
GrahamTek Flow Distributors were tested successfully over
1446 hrs. |
The
report on this pilot test can be downloaded here
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The Super-Flux Pilot was refitted with Seahan Membranes since
Nov 14 , 2006 and has been operating well since . Preliminary
data can be downloaded from here. |
The
report on this pilot test can be downloaded here |
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Reference Projects
