Membrane-Based (Waste)Water Reuse: State of the Art, Challenges and Opportunities

Transcription

1 Membrane-Based (Waste)Water Reuse: State of the Art, Challenges and Opportunities Santiago Romero-Vargas Castrillón, PhD Institute for Infrastructure and Environment and Institute for Materials and Processes School of Engineering University of Edinburgh CIWEM Wastewater Treatment Intensification Seminar London, 4 th December, 2018

2 Water Scarcity In red: {Rainfall Evapotranspiration} < Demand Water stress 2.4 billion people Driven mainly by population density Accentuated by climate change T. Oki, S. Kanae, Science, 2006, 313, 1068 J. H. Lienhardt V, Warren Lecture

3 Water Scarcity Cape Town Crisis Water use more than halved in 3 years (1.2bn L/d to 500m L/d) Financial Times (2 May, 2018)

4 Water Scarcity 1. Sao Paulo 2. Bangalore 3. Beijing 4. Cairo 5. Jakarta 6. Moscow 7. Istanbul 8. Mexico City 9. London 10. Tokyo 11. Miami

5 ½ of humanity lives within 100 km of the ocean seawater desalination What about the other half? wastewater Water Scarcity Membrane processes, especially Reverse Osmosis key role in augmenting the water inventory

6 Osmosis and Reverse Osmosis Osmosis Impaired water at p 1 Osmotic pressure, π, rises linearly with solute concentration Membrane permeable to water, but not solutes Fresh water at pressure p 1 Permeability coefficient Reverse Osmosis p 2 - p 1 > π Impaired water at p 2 JJ = AA pp ππ Fresh water at pressure p 1

7 RO Polyamide Membranes >99% NaCl rejection (70 bar, 40% recovery) A = 2-3 LMH bar -1 (SWRO), 3-5 LMH bar -1 (BWRO) Werber et al. Nature Reviews Materials, (2016) O C O O C O RMS roughness = nm Polysulfone support 10 µm 10 µm Cadotte, J. E. Interfacially synthesized reverse osmosis membrane. U. S. Pat. 4,277,

8 Reverse Osmosis Membranes G Sep, RO = 1.1 kwh m -3 Elimelech and Phillip, Science, 2011, 333, : Step change in desalination energy consumption 40 years on, formulation still in use by membrane manufacturers (Dow, GE, Toray) Cadotte, J. E. Interfacially synthesized reverse osmosis membrane. U. S. Pat. 4,277,

9 Membrane-Based Water Reuse Bedok NEWater Plant, 18 MGD. Singapore (2002) Recycled water Biological Treatment MF/UF Reverse Osmosis (suspended solids, (RO) bacteria and viruses) Changi NEWater Plant, 50 MGD. Singapore (2017) UV/H 2 O 2 Wastewater Wastewater Recycled water Membrane Bioreactor Reverse Osmosis (RO) (bioreactor, solids removal, RO pre-treatment) UV/H 2 O 2 Tang et al. Environ. Sci. Technol., 2018, 52,

10 Forward Osmosis (FO), an Emerging Membrane Process Mixed liquor Draw solution π Osmotic MBR for Wastewater Treatment JJ = AA ππ Achili et al., Desalination, 2009, 239,

11 Challenges and Opportunities for Membrane Development O C O O C O Polysulfone support

12 Low Selectivity small, hydrophilic, neutral contaminants Nitrosamines Boric acid HO B OH Werber et al. Environ. Sci. Technol. Lett., 2016, 3, OH

13 Low Selectivity NH 2 Cl / HOCl Waste water UF RO UV Oxidation (10 3 mj cm -2 ) NDMA R H 2 C H N N CH 3 CH 3 CH 3 HOCl/NH 2 Cl NH 2 Cl R H 2 C CH 3 H 2 N CH 3 N+ Cl N CH 3 HCl 2 HOCl/ 2 NH 2 Cl HC R RCH 2(O) H 2 O N+ H 3 C CH 3 O N N CH 3 CH 3 CH 3 CH 3 Mitch, W. A. and Sedlak, D. L. Environ. Sci. Technol. 2004, 38,

14 Low Selectivity NDMA removal Fujioka et al. Water Research, 2018, 131, 45-51

15 Improving selectivity 5 B av 90 B av (L m -2 h -1 ) R NDMA, av R NDMA, av (%) Graphene Oxide SW30 SW30-GO A av (L m -2 h -1 bar -1 ) A av (A/B) av (A/B) av (bar -1 ) 0.0 SW30 SW30-GO 0.0 Croll et al. Sep. Purif. Technol., 2019, 210,

16 Reactive Membranes Polyamide + Catalytic Nanoparticles physical + chemical removal Ru Ru Ru Ru Ru R H H Ru H H Huo et al. Environ. Sci. Technol., 2018, 52 (7), pp Ruthenium nanoparticles R N N O NH 3 H 2 O R 2 NH EPSRC Funded Project

17 Polyamide Surfaces: High Fouling Propensity Thin-film composite (TFC) Polyamide Hydrophobic Rough Carboxyl groups O C O O C O RMS roughness = nm Polysulfone support 10 µm 10 µm

18 Polyamide Surfaces: High Fouling Propensity Permeate flux Selectivity Membrane useful life M. Herzberg, M. Elimelech. J. Membr. Sci. 2006, 281, 70-87

19 Biofouling control Mitigate bioadhesion Inactivate bacteria RO membrane

20 Surface Modification FD 500 ml (%) Alginate fouling O C E NH (CH 2 ) 2 NH O E NH (CH 2 ) 2 NH C 0 control amino-pegde E = PEGDE H-bond acceptor Polar, hydrophilic Electrically neutral SRVC et al. J. Membr. Sci. 2014, 450,

21 Surface Modification P. fluorescens Bacterial Adhesion Force (nn) F Ad (nn) t Contact = 0 s t Contact = 2 s t Contact = 5 s Hydrophilic 0.2 Image not drawn to scale. 0.0 PSF BinAhmed et al. Environ. Sci. Technol. 2018, 52, PSF-PDA

22 Anti-(Bio)Fouling Electroactive Membranes Electroactive reduced Graphene Oxide (rgo) or Graphene High electron mobility Bactericidal activity

23 Anti-(Bio)Fouling Electroactive Membranes Electroactive reduced Graphene Oxide (rgo) or Graphene Electrically charged surfaces discourage attachment of bacterial cells

24 Anti-(Bio)Fouling Electroactive Membranes Multiple anti-fouling functionalities O 2(aq) + 2H + (aq) Membrane as cathode Ronen et al. Environ. Sci. Technol. 2018, 52, e - H 2 O 2 (aq)

25 Anti-(Bio)Fouling Electroactive Membranes Multiple anti-fouling functionalities Membrane as anode 2Cl - (aq) 2e - Cl 2 (aq)

26 Indirect potable reuse scheme put to a vote (2006) 62% of residents voted against the scheme Societal Challenges Public acceptance is a major challenge in the implementation of water reuse Toowoomba (Pop. 95,000) Main Source: water from dams Dams at 20% capacity in 2006

27 Societal Challenges Singapore Public Utilities Board Public engagement campaign Branding: NEWater Visitor Centre NEWater as opposed to recycled water Used water, not wastewater 98% of respondents would drink NEWater (2002 poll) mewr.gov.sg

28 Summary Reverse Osmosis Water Reuse A mature technology Challenges Selectivity Fouling Opportunities for nanotechnology Challenges in implementing water reuse are not confined to the technical realm

29 Thank you! Sara Binahmed Henry Croll Non-Tenured Faculty Award MN WRC 2015MN362B MRSEC Project 50628