EVALUATION OF POTENTIAL OF FORWARD OSMOSIS PROCESSES FOR WASTEWATER REUSE PURPOSES

De la Torre, T., Arnaldos, M., Corzo, B., Ferrero, E., Navea, S., Simón, P., Rodríguez, C., Malfeito, J.J.

ACCIONA Agua and ESAMUR

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

FO opportunities and challenges

Why? Low and reversible fouling

Less pretreatment

Less chemical cleaning

Product water customization (e.g. boron removal, fertigation)

Improvements in FO membranes: Thinner membranes with less

tortuosity (S parameter)

less ICP and higher flux

More providers lower prices

(Mi and Elimelech, 2009)

(Achilli et al., 2010)

Market niches in wastewater reclamation Industrial wastewater • Requiring high quality and complex treatment • With fouling problems (requiring extensive pretreatment) • Applications with no DS separation • Residual heat • Case-specific

Municipal wastewater Potable reuse •Indirect or direct (Singapur/Namibia…) •Multibarrier concept is state of the art

Industrial •Cooling towers

Agriculture •Boron •Micropollutants •Salinity •Heavy metals

Source: AQUAREC, 2006

FO opportunities and challenges

FO Challenges Low flux (ICP & ECP)

DS recovery is energy intensive

DS costs (Js and incomplete DS recovery)

Permeate quality

No data: main studies are lab-scale, synthetic feed, short term and batch

Realistic studies are still needed

This study: 2 FO-pilot plants operating with real feed, continous, long-term (months):

FO-NF

FO-MBR

FO opportunities and challenges

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

FO-MBR

Pilot scale FO-MBR plant

• Feed: 4L/min, 1 bar • DS: 1L/min, 0.5 bar • DS concentration: 1.5 M • Activated sludge (AS) conductivity: 1000 S/cm • Continuous operation during one month per

selected DS using real activated sludge

Membrane test cell (CTA, HTI)

FO-MBR: Results

• 2 DS selected after modelling: K4P2O7 and HCOOK • Sustained long-term operation with minimal fouling and

consistent water fluxes for K4P2O7 and HCOOK • No chemical cleaning • Similar Js and Jw for both DS

K4P2O7 HCOOK

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

FO-NF plant

LIFE-OFREA FO-NF demonstration plant • Region of Murcia: 98% of wastewater is reused, mostly in

agriculture. The rest present high salinity • San Pedro del Pinatar WWTP effluent:

• Conductivity: 4-6 mS/cm • Boron: 1.5 ppm

• www.life-ofrea.com

Simulation between modules in series using Matlab

Experimentation with commercial elements in batch

Feed water

FO-NF plant: design

FO-NF plant

LIFE-OFREA FO-NF demonstration plant • Commisioning December 2014 • 3 m3/h effluent from WWTP of San Pedro del Pinatar (Murcia,

Spain)

FO-NF plant: permeability evolution • Stable operation of the FO • NF permeability decreased due to fouling but then stabilized • Permeability FO=Flux/( DS feed T corrected• Permeability NF=Flux/NDP (T corrected)

FO-NF plant: permeate quality • Stable permeate quality • Low conductivity • B < 0.4 mg/L (>70% removal) • High quality for agricultural reuse except for SAR > 100 mequ/L

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

UF+RO vs. FO+RO:

CAPEX:

Membrane prices for FO should go down in the future years

OPEX:

Energy consumption is higher for the FO+RO (this study; McGovern and Lienhard, 2014,..)

Chemicals

• Low fouling: • Membrane replacement and chemicals for cleaning and shutdowns

will be lower for the FO option.

• Low or zero pretreatment: no antiscalant, pH adjustment, FeCl3,…

• Draw solution costs due to Js and incomplete recovery economical DS must be found

Cost comparison

Index

1. FO opportunities and challenges

2. Long-term experimentation FO-MBR pilot plant

FO-NF demonstration plant

3. Costs: first impressions

4. Conclusions

Conclusions • Niches of FO in wastewater reclamation:

• Potable reuse

• Agricultural reuse: specially if 2-RO passes are needed

• Industrial uses

• FO-NF & FO-MBR operated in the long term with real feed: • Stable operation

• High permeate quality (conductivity and boron)

• SAR must be adjusted

• No fouling in the long-term

• Costs • Relevant cost due to DS losses and DS reconcentration energy

• Balance between cost of DS, membranes and energy needed

FO application is still challenging…but is becoming a reality!

Acknowledgements We would like to thank the collaboration of Aguas y Servicios de la Costa Tropical and HTI for the membrane coupons.

The research leading to these results has received funding from:

• LIFE+ Programme of the European Commision (LIFE12/ENV/ES/000632 LIFE OFREA) www.life-ofrea.com

• People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013 under REA agreement 289193 (SANITAS Project). www.sanitas-itn.eu

teresa.torre.garcia@acciona.com

This presentation reflects only the author's views and the European Union is not liable for any use that may be made of the information contained therein.