Forward Osmosis-Low Pressure Reverse Osmosis
Indirect Desalination and Engineered potable reuse in the costal regions
Zhenyu Li
Rodrigo Valladares Linares
Noreddine Ghaffour
Gary Amy
08-29-2015
Water Desalination and Reuse Center, KAUST
OUTLINE
Why FO?
Different Feed Water Conditions
Membrane Fouling
Reverse Salt Diffusion
Contaminants Removal/Rejection
Membrane Cleaning and Flux Recovery
Cost Analysis
Why FO?
Membrane processes are now commonly used in water reuse and
drinking water production (i.e. desalination)
Forward osmosis (FO) represents a new opportunity to solve the global
water crisis
• Low-energy requirement compared to
high-energy processes (RO/NF)
• Lower fouling propensity which may
increase cleaning efficiency
• Bridge to integrate different processes
Other options for WW recovery…
Membrane bioreactors (aerobic and anaerobic)
Osmotic membrane bioreactor
Tertiary treatment with NF/RO membranes
Advanced oxidation processes
omegamanjournal.wordpress.com
www.pollutionsolutions-online.com
Energy intensive
4
Concept of FO-LPRO
Indirect desalination
1
9
2
3
4
5
6
7
8
10
11
Concept of FO-LPRO
Engineered direct potable reuse
Double barriers to reject the contaminants from wastewater
Indirect desalination:
effect of feed water condition
Urban runoff
Indirect desalination:
fouling at feed (quality-impaired water) side
Urban runoff Secondary WW Primary WW
Membrane could be fully
covered by organic fouling
layer.
Biopolymer is the main
foulant in the case of
municipal WW.
Indirect desalination:
fouling at draw solution (seawater) side
1.E+00
1.E+01
1.E+02
1.E+03
/通用格式 /通用格式 /通用格式 /通用格式 /通用格式
Adenosine triphosphate (ATP)
Membrane + spacer
Spacer
pg/c
m2
Sampling location
Biofouling cannot be avoided at seawater (as the draw solution) side and will be crucial for the
process performance in the long-term operation.
Spiral-wound
Indirect desalination:
reverse salt diffusion
Urban runoff
Indirect desalination:
contaminants removal from feed water
Trace metals
Synthetic urban runoff
vs.
DS (NaCl)
Synthetic primary wastewater effluent
vs.
DS (NaCl)
Secondary wastewater effluent
vs.
Natural seawater
Synthetic primary wastewater effluent
vs.
Natural seawater
Batch process
Nutrients in municipal WW
Indirect desalination:
contaminants removal from feed water
100%
100%
100%90%
90%
90%
83%
67%
52%85%
85%
75%
75%
85%
64%
Nutrients in Unban Runoff
Indirect desalination:
contaminants removal from feed water
Indirect desalination:
contaminants removal from feed water
HL neutral HB neutral Ionic
OMPs in municipal WW
Indirect desalination:
contaminants removal from feed water
Naphthalene Phenanthrene
PAHs in urban runoff
60%
65%
70%
75%
80%
85%
90%
95%
100%
Flux Decline AfterOperation
Osmotic Backwash Air Scouring in situAL
CC Alconox+EDTAAL
CC Alconox+EDTASL
Flu
x r
eco
very
(%
)
75.2%72.8%
89.5%
93.6%94.5%
Feed: secondary WW effluent
Draw: seawater
Indirect desalination:
membrane cleaning for flux recovery
Long term operation – air scouring
0
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Flu
x (
LM
H)
Time (Days)
90.3% 89.9% 88.5%
Indirect desalination:
membrane cleaning for flux recovery
Feed: secondary WW effluent
Draw: seawater
Indirect desalination:
total TDS removal by FO-LPRO
More than $55 billion worth of oil is consumed annually in Saudi Arabia only for generating energy for seawater desalination (>4kWh/m3)
The linkage of Osmotic Pressure and Energy
for Seawater Desalination
FO-LPRO SWRO MBR-RO-AOP SWRO+MBR-RO-AOP0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
Wa
ter
tota
l co
st ($
US
D m
-3)
Technology
Cost analysis
Conclusions
FO is favorable as a low-cost pre-treatment process to reduce
either energy consumption or fouling risk in post-treatment for
product water recovery.
FO is a bridge to integrate waste water treatment/reuse and
seawater desalination in the costal regions.
FO-LPRO provides double barriers to secure the product water
quality.
FO-LPRO has an economic advantage compared to current
available technology for SWRO, and comparable costs with a
wastewater treatment and recovery system
Acknowledgements