University of Oklahoma College of Engineering - WaTER Center Speaker Series http://www.ou.edu/coe/centers/water.html

1. Science and Technology for
Sustainable Water Supply
Menachem Elimelech
Department of Chemical Engineering
Environmental Engineering Program
Yale U i
Y l University
it
Seminar, University of Oklahoma, February 20,
2009

2. The “Top 10” Global Challenges
for the New Millennium
1.
1 Energy
2. Water
3. Food
4. Environment
5. Poverty
6. Terrorism and W
T i d War
7. Disease
8.
8 Education Richard E Smalley Nobel
E. Smalley,
9. Democracy Laureate, Chemistry, 1996,
10. Population MRS Bulletin, June 2005

3. International Water Management Institute

4. Regional and Temporal Water
Scarcity
S it
National Oceanic and Atmospheric Administration

5. How Do We Increase the Amount
of Water Available to People?
Water conservation repair of infrastructure
conservation, infrastructure,
and improved catchment and distribution
systems ― improve use not increasing
use,
supply!
Increase water supplies t gain new waters
I t li to i t
can only be achieved by:
Reuse of wastewater
R f t t
Desalination of brackish and sea waters

6. Many Opportunities
We are far from the thermodynamic limits for
separating unwanted species f
ti t d i from water
t
Traditional methods are chemically and
y
energetically intensive, relatively expensive,
and not suitable for most of the world
New systems based on nanotechnology can
dramatically alter the energy/water nexus
y gy

8. Wastewater Reuse
W t t R

9. Reclaimed Wastewater in
Singapore (NEWater)
Source of water
supply f
l for
commercial and
industrial sectors
(10% of water
demand)
4 NEWater p a ts
ate plants
supplying 50 mgd
of NEWater.
Will meet 15% of
5 miles
water demand by
2011

10. Reuse of Wastewater in Orange
County,
County California
www.gwrsystem.com Groundwater Replenishment
System (70 MG/day))
Prado
Dam
Santa Ana River Facilities

11. GWR System for Advanced Water
Purification (Orange County)
Microfiltration Reverse Ultraviolet
(MF) Osmosis Light with
(RO) H2O2
OCSD
Secondary
WW Recharge
Effluent Basins

12. Namibia,
Namibia Africa

13. Natural Beauty … but not Enough
Water

14. Windhoek’s Solution: Wastewater
Reclamation for Direct Potable Use
Goreangab Reclamation Plant (Windhoek)
“Water should not be
Water
judged by its history,
but by its quality.”
y q y
Dr. Lucas Van Vuuren
National Institute of Water
Research, S th Af i
R h South Africa
The only wastewater reclamation plant
y
in the world for direct potable use

15. The Treatment Scheme: A
Multiple Barrier Approach

16. Most Important: Public Acceptance
and T
d Trust i the Q li of W
in h Quality f Water
Breaking down th psychological b i (th
B ki d the h l i l barrier (the
“yuck factor”) is not trivial
– Ri
Rigorous monitoring of water quality after every
it i f t lit ft
process step
– Final product water is thoroughly analyzed (data
made available to public)
The citizens of Windhoek have a genuine
pride in the reality that their city leads the
world in direct water reclamation

17. Wastewater Reuse: Membrane
Bioreactor (MBR)-RO System
Shannon, Bohn, Elimelech, Georgiadis, and Mayes, Nature 452 (2008) 301-310.

18. Fouling Resistant UF Membranes:
Comb (PAN-g-PEO) Additives
amphiphilic copolymer added
hi hili l dd d segregate & self-organize
t lf i
to casting solution at membrane surfaces
PEO brush
layer on
surface and
inside pores
Casting Doctor
Solution Blade Heat
Treatment
Fouling
Casting Solution
Coagulation
Doctor Blade
Heat Treatment
Bath
Coagulation Bath Bath
Resistance
Asatekin, Kang, Elimelech, Mayes, Journal of Membrane Science, 298 (2007) 136-146.

19. Fouling Reversibility (with
Organic Matter)
O )
White: Pure water
Whit P t
Gray: recovered flux
after fouling/cleaning
(following “physical”
cleaning (rinsing)
with no chemicals)
Shannon, Bohn, Elimelech, Georgiadis, and Mayes, Nature 452 (2008) 301-310.

20. AFM as a Tool to Optimize
Copolymer for Fouling Resistance
4
2
N/m)
0
F/R (mN
-2
-4 PAN (P0-0)
P50-5
-6 P50-10
P50 20
P50-20
-8
Kang, Asatekin, Mayes, Elimelech, Journal of Membrane Science, 296 (2007) 42-50.

21. Force Distribution Provides the
Necessary Information
60
PAN (P0-0) 60 P50-5
45
%)
45
requency (%
%)
equency (%
30 30
15 15
Fre
Fr
0 0
-12 -10 -8 -6 -4 -2 0 -12 -10 -8 -6 -4 -2 0 2 4
F/R (mN/m) F/R (mN/m)
60
P50-10 60
P50-20
45 45
%)
%)
Frequency (%
requency (%
30 30
15 15
Fr
0 0
-1 0 1 2 3 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
F/R (mN/m) F/R (mN/m)

22. Wastewater Reuse: Membrane
Bioreactor (MBR)-RO System
Shannon, Bohn, Elimelech, Georgiadis, and Mayes, Nature 452 (2008) 301-310.

23. One Step NF MBR System?
NF-MBR
NF

24. Antifouling NF Membranes for
MBR (PVDF g POEM)
(PVDF-g-POEM)
Filtration of activated sludge from MBR
– PVDF-g-POEM NF: no flux loss over 16 h filtration
– PVDF base: 55% irreversible flux loss after 4 h
1.4
1.2
malized flux
1.0
0.8
PVDF-g-POEM (●,●)
0.6
Norm
PVDF base (• •)
(•,•)
0.4
0.2
0.0
0 12
Time (hours)
Asatekin, Menniti, Kang, Elimelech, Morgenroth, Mayes: J. Membr. Sci. 285 (2006) 81-89

25. MBR and the Sanitation Crisis in
D
Developing C
l i Countries
ti
1.1 billion people ⎯ or one
sixth of the world’s population
⎯ lack access to safe water
2.4 billion are without
adequate sanitation
Between 2 to 4 million deaths
a year are attributed to unsafe
water,
water mostly due to water
water-
borne preventable diarrheal
diseases

26. MBR as a Decentralized Sewage
Treatment Option
T t t O ti
Centralized sewage treatment (wastewater treatment
plants) is not realistic (long-term goal)
MBR may be ideal for localized, decentralized sewage
treatment in the developing world
Advantages: small footprint, flexible design, and
automated operation

27. Desalination:
Reverse Osmosis

28. Population Density Near Coasts

32. Seawater Desalination
Augmenting and diversifying water supply
Reverse osmosis and thermal desalination
(MSF and MED) are the current desalination
technologies
Energy intensive (cost and environmental
impact)
Reverse osmosis is currently the leading
technology

33. Reverse Osmosis
Major improvements in the past 10 years
Further improvements are likely to be
incremental
Recovery limited to ~ 50%:
Brine discharge (
B i di h (environmental concerns)
i t l )
Increased cost of pre-treatment
Use prime (electric) energy (~ 2.5 kWh per
cubic meter of product water)

34. Minimum Energy of Desalination
Minimum energy needed to desalt water is
independent of the technology or mechanism of
desalination V 2
1
3.5
35 W= ∫Π dV
Minimum Energy (kW-h/m )
V1 − V2
3
os
O
3.0 100 C V1
O
25 C
2.5
25
(
2.0
Minimum theoretical energy
for desalination:
1.5
15
0% recovery: 0.7 kWh/m3
1.0
50% recovery: 1 kWh/m3
0.5
05
M
0 20 40 60 80 100
Percent Recovery

35. Nanotechnology May Result in
Breakthrough Technologies
“These nanotubes are so beautiful
that they must be useful for
something. . .”, Richard Smalley
(1943-2005).

36. Aligned Nanotubes as High Flux
Membranes for Desalination?
Hinds et al, “Aligned multi-walled carbon nanotube
membranes”, Science, 303, 2004.

37. Research on Nanotube Based
Membranes
Mauter and Elimelech,
Environ. Sci. Technol., 42
(16), 5843-5859, 2008.

38. Next Generation Nanotube
Membranes
M b
Mauter and Elimelech,
Elimelech
Environ. Sci. Technol., 42
(16), 5843-5859, 2008.
Single-walled carbon nanotubes (SWNTs) with a pore
size of ~ 0.5 nm are critical for salt rejection
Higher
Hi h nanotube d
t b density and purity
it d it
Large scale production?

39. Bio-inspired High Flux
Membranes for Desalination
Natural aquaporin proteins extracted from living
organisms can be incorporated into a lipid bilayer
membrane or a synthetic polymer matrix

40. BUT …. Energy is Needed Even for
Membranes with Infinite Permeability
Minimum theoretical
energy for desalination at
gy
50% recovery: 1 kWh/m3
Practical limitations: No
less than 1.5 kWh/m3
Achievable goal:
g
1.5 − 2 kWh/m3
Shannon, Bohn, Elimelech, Georgiadis, and Mayes, Nature 452 (2008) 301-310.

41. Desalination:
Forward Osmosis

42. The Ammonia-Carbon Dioxide Forward
Osmosis Desalination Process
Nature, 452, (2008) 260
Energy
Input
McCutcheon, McGinnis, and Elimelech, Desalination, 174 (2005) 1-11.

43. NH3/CO2 Draw Solution
NH3(g) CO2(g)
NH3(g) CO2(g)
NH4HCO3(aq)
(NH4)2CO3(aq)
NH4COONH2(aq)
HEAT

44. High Water Recovery with FO
RO FO
450
400 Seawater π
350
300
250
π (atm) 200
150
100
50
0
0 10 20 30 40 50 60 70 80 90 100
Recovery (%)
R

45. Energy Use by Desalination
Technologies (Equivalent Work)
6
MSF
MED-TVC
5 MED-LT
RO
FO-LT
4
3
kWh/m
3
2
1
Contribution from
Electrical Power
0
McGinnis and Elimelech, Desalination, 207 (2007) 370-382.

46. Waste Heat Geothermal Power

47. Concluding Remarks
g
We are far from the thermodynamic limits
y
for separating unwanted species from water
Nanotechnology and new materials can
significantly advance water purification
technologies
Advancing the science of water purification
g p
can aid in the development of robust, cost-
effective technologies appropriate for
g pp p
different regions of the world

48. Acknowledgments