Durante la celebración de la 13º Edición de IWA Leading Edge Conference on Water and Wastewater Technologie Iwa-LET 2016 que se está celebrando estos días en Jerez, Marina Arnaldos y Beatriz Corzo realizaron una ponencia dentro de un taller sobre desalación sostenible. On occasion of the 13th IWA Leading Edge Conference on Water and Wastewater Technologies (IWA-LET 2016), which is being held in Jerez, Marina Arnaldos and Beatriz Corzo presented two papers in a workshop on sustainable desalination.

1. The 13th IWA Leading Edge Conference
on Water and Wastewater Technologies
DEVELOPMENT AND APPLICATION OF SUSTAINABLE
MEMBRANE DESALINATION TECHNOLOGY: REVERSING
WATER SCARCITY AND FAST FORWARDING TO THE
FUTURE
FEASIBILITY OF FORWARD OSMOSIS FOR DESALINATION AND
WATER RECLAMATION: APPLICATION EXAMPLE AT PILOT
SCALE
BEATRIZ CORZO

2. 2
INDEX
 Water Scarcity and Wastewater Reuse
 Hybrid FO advantages
 FO challenges
 OFREA Project
Design
Demonstration plant
Cost evaluation
 Conclusions
 Acknowledgments

3. 3
WATER SCARCITY AND WASTEWATER REUSE
 >3 Billion people will live under water stress in 2025 (Valladares et al.,
2014)
 Options:
‒ Water desalination
‒ Water reuse
‒ Improve water efficiency
Can we compete using FO in water reuse for agricultural
purposes?
A combination of the
three is needed
Challenges for water reuse are both technological and
economical: technologies that can assure safe water at a
competitive price are needed

4. 4
Water Recycling Guidelines:
 Depend on local context
 Mainly bacteriological parameters
 E.coli
 Nematode eggs
 Giardia
 Criptosporidium
 Others:
 Nutrients (N and P)
 Suspended solids
 Turbidity
 Dissolved salts
 Heavy metals
 Boron
 Harmful organic substances
WASTEWATER REUSE
Sand filtration/O3/AC/MBR/
biological treatment/floculation….
MF/UF+RO (one or two passes)
F+EDR+Disinfection+AOPs
Hybrid FO?
What water quality do we need?

5. 5
HYBRID FO ADVANTAGES
 Multibarrier concept
‒ High permeate quality
 Low and reversible fouling
‒ Less pretreatment
‒ Less chemical cleaning
 Product water customization (e.g. boron
removal, fertigation)

6. 6
FO CHALLENGES
 Low flux (ICP & ECP) and expensive elements
‒ Improvements in FO membranes:
# Thinner membranes with less tortuosity (S parameter) → less ICP and higher flux
# More providers → lower prices
 DS recovery is energy intensive.
‒ Diluted DS has more osmotic pressure than feed water
 DS replacement costs
‒ Reverse salt diffusion and incomplete DS recovery
 Permeate quality
‒ DS content
 No real data
‒ Main studies are lab-scale, synthetic feed, short term and batch conditions.
Realistic studies are still needed → OFREA PROJECT

7. 7
OFREA PROJECT
 According to a workshop on water reuse:
(Optimizing water reuse in EU. Dec 2014)
‒ Water reuse in Spain: 35%
‒ Region of Murcia: 98%
of wastewater is reused,
mostly in agriculture.
The rest presents
high salinity
Reuse Datebase (CEDEX). R. Iglesias, 2007

8. 8
OFREA PROJECT
FO-NF pilot plant is operating with real feed,
continuous and long-term (> 1 year):
 Feed water: San Pedro del Pinatar 3 m3/h WWTP
effluent
– Conductivity: 4-6 mS/cm
– Boron: 1.2 ppm
– SAR: 10.6
 RD 1620/2007 limit:
– Conductivity: 3 mS/cm
– Boron: 0.5 ppm
– SAR: 6

9. 9
OFREA PROJECT: PREVIOUS DESIGN
FO MEMBRANE SELECTION
 5 membrane brands tested with different configuration.
‒ TFC membrane showed the
best performance.
‒ TFC was the selected for the
demonstration plant.
Porifera
membrane
was selected

10. 10
OFREA PROJECT: PREVIOUS DESIGN
DS SELECTION
 Different families. Different Van’t Hoff and diffusivity properties.
• High osmotic pressure obtained by formate
• Conductivity must be carefully used as control variable

11. 11
OFREA PROJECT: PREVIOUS DESIGN
DS SELECTION
 Dynamic test. Spiral wound commercial element.
 Asymptotic behavior is caused by internal concentration polarization.
 For 10 bar no significant differences.
 KCOOH the best in terms of flux. Expensive.
 Compromise between CAPEX and OPEX.
 NF recovery method has been chosen.
Draw
Solution
FO
Flux
Reversal
flux
losses
DS
losses in
permeate
Cost of
product
Cost of
replacement
Recovery
method
HMWP + - - - - ++ - NF
NaCl + + + - - - RO
HCOOK ++ + + ++ ++ RO
MgSO4 - - - - - NF
K4P2O7 + ++ ++ + ++ NF
- Low
+ High

12. 12
OFREA PROJECT: DEMONSTRATION PLANT
The first and largest Hybrid-FO
demonstration plant worldwide for
reclamation in agricultural
purposes.
84 m2
30 m2

13. 13
OFREA PROJECT: DEMONSTRATION PLANT DATA
 Stable operation of the
FO (22% of loss of flux
the first days)
 NF permeability
decreased due to
fouling:
‒ Using an organic DS.
‒ Using an inorganic DS
and increasing
permeate flowrate.
Silicates and gypsum
presence.
Specific flux or permeability
FO=Flux/(пDS – пfeed)
NF=Flux/(NDP)

14. 14
OFREA PROJECT: PERMEATE QUALITY
 Stable permeate quality
 Low conductivity except
for initial NF membranes
 B < 0.4 mg/L (>70%
removal)
 High quality for
agricultural use!
A change in NF: savings in
chemical consumption
but more energy is used

15. 15
OFREA PROJECT: COST EVALUATION
 DS reposition and energy consumption
 No chemical cleaning in FO membranes
(1) DS price is referred to a small-
scale order
(2) It is assumed 0.10€/KWh
(3) NF Membranes fouled
NF HF
NF HR

16. 16
COST EVALUATION AND CONCLUSIONS
UF+RO
€/m3
FO+NF
€/m3
0.35-0.45 0.96
TERTIARY TREATMENT
LET’S GO DOWN THE PRICES! We demand:
 An improvement in FO membranes permeability.
 To find a really cheap DS with ↑Van’t Hoff coefficient.
 To regenerate the DS with other systems: MD (waste heat or solar energy)
LARGE SCALE PILOT SCALE

17. 17
CONCLUSIONS
 FO-NF operated in the long term with real feed:
‒ NF membrane was fouled with the organic DS and the first inorganic DS.
‒ FO membrane is working with stable permeability. No fouling in the long-term.
‒ High permeate quality (conductivity, SAR and boron are below legislation).
 Costs
‒ NF chemical cleaning is related to DS. No cleaning in FO membranes.
‒ No remineralization is needed.
‒ Relevant costs due to low permeability of FO membranes, DS losses and DS
reconcentration energy.
‒ To implement our new DS has decreased the prices relevantly.
Economic feasibility of hybrid FO is highly dependent on all these factors.
IN A NEAR FUTURE COULD BE CHEAPER THAN CONVENTIONAL SYSTEMS!

18. 18
ACKNOWLEDGMENTS
 The research leading to these results has received funding
from the LIFE+ Programme of the European Commission
(LIFE12/ENV/ES/000632 LIFE OFREA) and from La
Generalitat de Catalunya (Industrial PhD program).
 All my colleagues from Acciona Agua and Carme Sans from
the University of Barcelona.