Advancements in Membrane Technology: Standardizations and Innovations in Drinking Water Applications. June 17, 2016

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1 Advancements in Membrane Technology: Standardizations and Innovations in Drinking Water Applications June 17, 2016 Jarrett Kinslow, PE Jill Hudkins, PE

2 Agenda Introduction and Review of Membrane Technologies Membrane Filtration (MF/UF) Overview, Applications & Innovations Membrane Separation (NF/RO) Overview, Applications & Innovations Summary SAWS Brackish Groundwater Desalination Approaching Completion (Yesterday)

3 Introduction 1

4 Introduction Typically, water treatment processes can be broken down into the following categories: Chemical Physical Biological Membrane treatment processes can be generally classified as physical processes in which constituents are separated from the raw water.

5 Drivers for Membrane Treatment Limited and deteriorating supplies require the use of alternative water sources Technological innovation leading to development of low cost, high quality water treatment solutions Membranes offer cost effective solutions Increasing regulatory standards especially regarding disinfectant by-products and waterborne pathogens Retrofit of old technology to protect the public from aging or underperforming systems Growing demand due to population growth

6 Membrane Types Membrane Contaminants Support Material Flat Sheet Thin Film Composite (RO/NF) Hollow Fiber (MF/UF)

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8 Membrane Selection Algae Cryptosporidium Bacteria Turbidity Giardia MICROFILTRATION Organic Macromolecules Asbestos Viruses ULTRAFILTRATION Hardness Color NOM Radionuclides SOC s NANOFILTRATION > 0.1 micron micron, >2000 MW > micron, >180 MW Salts RO H 2 O > micron, Ions > 20 AW

9 Membrane Processes Membrane Filtration: Size Exclusion (Sieving) Microfiltration, MF Ultrafiltration, UF Membrane Separation: Diffusion Controlled Nanofiltration, NF Reverse Osmosis, RO (Low Pressure/Brackish Water) Seawater Reverse Osmosis, SWRO Non-Water Permeable: Charge Controlled Processes Electrodialysis, ED Electrodialysis Reversal, EDR

10 Membrane Filtration 1

11 Membrane Filtration (MF/UF) Hollow Fiber Membranes Bundles or Cassettes Microfiltration (MF) Process removes particles / turbidity / bacteria / and protozoa Pressure Range: 4-70 psi Configuration: Hollow Fiber Ultrafiltration (UF) Process removes particles / turbidity / bacteria / protozoa and virus Pressure Range: psi Configuration: Hollow Fiber

12 Membrane Filtration (MF/UF) Various forms are available Vacuum Driven (submerged in tank) Pressure Driven (in pressure vessels, normally vertical) Typically operates in dead end mode (like a media filter) System operates for a prescribed run period (determined by recovery) Concentrate waste from a short duration backwash (backpulse cycle)

13 MF/UF Membranes Membranes are manufactured as hollow fibers Materials include PP, PVDF, PES, and others Most are resistant to high levels of chlorine Hollow fibers are engineered to provide a specific pore size

14 UF Membranes = Effective Barrier Membrane Fiber Hollow strands of porous plastic fibers with billions of microscopic pores on the surface The pores are thousands of times smaller in diameter than a human hair Pores form a physical barrier to impurities but allow pure water to pass Electron microscope view of membrane surface

15 Operating Modes Inside Out, Flow Thru Inside Out, Dead End Outside In

16 MF/UF Treatment Units Hollow fibers are bundled into cassettes for immersed service or enclosed vessel modules Operated in inside-out or outside-in and dead end or recirculation modes Pressure is applied to the feed or a vacuum is applied to the fibers

17 MF/UF System Design Parameters Flux rates decrease with increasing fouling potential To Increase Capacity: Add membrane area (more membrane elements in parallel) To Increase Recovery: Add pretreatment To Increase Quality: Membrane material, pore size Recovery limited feed pressure limitations and effectiveness of backwash cycles

18 MF/UF Applications Retrofit for Existing Media Filters Surface Water Treatment (LT2ESWTR) GroundWater Under Direct Influence (GWUDI) Pretreatment to RO/NF (Integrated Membrane Systems) Seawater RO (SWRO) Brackish Surface Water Water Reuse (IPR/DPR)

19 Ultrafiltration Pathogen Removal 4 to 6 micron 0.1 micron pore size Giardia (4-14 microns in diameter) Cryptosporidium (4-6 microns in diameter)

20 Raw Wastewater Wastewater Treatment/Reuse Secondary Treatment w/tertiary Filtration Permeate Disinfection Vacuum Pump Membrane Bioreactor Reclaimed Water Membrane Filtration Modules Secondary Treatment w/membrane Filtration Strainer Feed Pump Membrane Filtration System

21 MF/UF Additional Considerations Commercial offerings are typically proprietary systems, packaged by the membrane manufacturer (Pall, GE, Evoqua) Most components are not inter-changeable Recent market trends are towards standardization of membrane elements Many state regulatory agencies require pilot testing Challenge testing Direct integrity testing (pressure decay test)

22 MF/UF Innovations Solids and Turbidity Resiliency Membrane Fibers Low Fouling PVDF Membrane Chemistry Improved Durability of Membrane Fibers Membrane Cassettes/Bundles Modular Construction and Flexibility for Expansion Encased vs. Submerged Installations Enhanced Methods for Maintaining System Performance (CEB, Mini-Cleans, CIP)

23 MF/UF Systems - Market Trends MF/UF Market has traditionally been dominated by suppliers of complete pre-engineered systems: Significant differences in modules, operational conditions, and cleaning required custom tailored systems Required selection of system supplier prior to completing the plant design Owner often must sole-source future membrane replacements and future service/parts

24 MF/UF Systems - Market Trends (cont.) Interchangeable rack MF/UF systems are changing the ways systems are designed and constructed: Piping and supporting equipment are designed to work with multiple membrane manufacturers (non-proprietary alternative) Allows detailed design to be completed without a final membrane manufacturer selection Compatibility with 3-6 different membrane manufacturers Improved convergence of suppliers of MF/UF with NF/RO (benefits applications for integrated membrane systems)

25 Membrane Separation 1

26 Membrane Separation (RO/NF) Thin Film, Flat Sheet Membranes Spiral Wound Nanofiltration (NF) Process removes turbidity / virus / color / pesticide / NOM / pesticide / and hardness Pressure Range: psi Configuration: Spiral Wound Sheet Reverse Osmosis (RO) Process removes turbidity / color / pesticide / NOM / pesticide / hardness / salinity removal / nitrate / arsenic Pressure Range: psi Configuration: Spiral Wound Sheet, Hollow Fiber

27 Membrane Sheet Surface Semipermeable membrane layer ~2000 Angstrom Microporous polymeric support Fabric backing 0.2 mm 0.008"

28 Membrane Construction PA membrane surface Polymeric support Fabric backing

29 Membrane Separation (NF/RO) Always pressure driven (normally horizontal pressure vessels) Operates in cross flow mode, producing a constant flow of concentrate (volume determined by recovery) System operates continuously, and the higher TDS concentrate is produced in proportion to the permeate flow stream

30 Diaphragm Reverse Osmosis Reverse osmosis is achieved by providing adequate pressure to overcome the osmotic pressure so that the feed water flows from the more concentrated solution to the fresh water side of the membrane. P>P O 1,500 mg/l 100 mg/l Water

31 Membrane Element Dimensions Diameter: 200 mm, 8 Length: 1 m, 40

32 RO/NF Membrane Element Feed Brine Spacer Concentrate Product Membrane Permeate Carrier

33 RO/NF Pressure Vessel Assembly Feed O-rings Interconnector Brine Seal Permeate Head Seal Pressure Vessel Thrust Cone Head End Adapter R.O. Element Concentrate Retaining Ring

34 Pressure Vessel Flow-streams 44 gpm feed 22 gpm permeate 22 gpm concentrate

35 Element Cross-Section Trust ring Interconnector Pressure vessel End plate Feed or concentrate port Connector - adaptor Section of RO element

36 Reverse Osmosis System Schematic Pretreatment Raw Water Blend Post Treatment Raw Water Finished Water High Pressure Pumps Stage 1 Membrane Treatment Permeate Stage 2 Concentrate to Disposal

37 RO/NF System Design Parameters Flux rates decrease with increasing fouling potential To Increase Capacity: Add membrane area (more pressure vessels in parallel) To Increase Recovery: Concentrate Staging - 1 st stage concentrate becomes 2 nd stage feed To Increase Quality Permeate Staging 1 st stage permeate becomes feed to 2 nd Pass Recovery limited by limiting salts and/or feed pressure limitations (energy costs)

38 NF/RO Applications Membrane Softening (NF) Color / Organics Removal (NF, Stage 2 DBPR) Brackish Water (BWRO) Nitrate Removal Arsenic Removal Industrial Water Treatment (Boiler, Manufacturing, ect.) High Purity / Ultrapure Water Seawater Desalination (SWRO) Water Reuse (LPRO) Food & Beverage, Bottled Water

39 Finished Water Membrane Softening vs. Lime Softening Lime/Polymer Lime-Soda Ash Process Raw Water w/hardness, Color, Iron Nitrates and Organics Solids Contact Unit (Softener) Raw Water Blend Rapid Media Filtration Blending Basin Post Treatment Pretreatment High Pressure Pumps Stage 1 Membrane Softening Skids Permeate Membrane Softening Process Stage 2 Concentrate to Disposal

40 Dissolved Inorganic Solutes (Brackish GW) Existing Treatment Process Raw Water Raw Water Blend Blending Basin Post Treatment Finished Water Pretreatment High Pressure Pumps Stage 1 NF/RO Membrane Skid Permeate Reverse Osmosis Treatment Process Stage 2 Concentrate to Disposal

41 NF/RO Additional Considerations Commercial offerings are standardized with inter-changeable vessels and membrane elements Systems packaged by Membrane OEMs State regulatory agencies may accept membrane projections (software), some still require pilot testing Method of concentrate disposal

42 NF/RO Innovations Energy Reduction Low Energy (Higher Permeability) Membranes Optimized Feed Channel Spacers Energy Recovery Devices Process Optimizations Port St. Lucie Energy Recovery Device Fouling Resistant Membranes Improved Pretreatment Chemicals High Recovery RO Designs (Concentrate Minimization) Multi-ported Pressure Vessels Center Feed Vessels (Nanofiltration)

43 NF/RO Innovations Product Innovations Large Diameter Elements High Surface Area Elements (Automated Manufacturing) Interlocking Membrane Elements 8 element vs. 16 element

44 Summary Membrane technology is rapidly becoming more mainstream throughout the US Costs can be competitive with conventional treatment Membrane technology continues to evolve with innovation Pilot Scale and Demonstration Scale Testing is always beneficial