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