4/04/13

Membrane Technology

PURPOSE PROCESS PAYOFF

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§ PURPOSE: PROVIDE AN OVERVIEW OF MEMBRANE TECHNOLOGY.

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§ PROCESS: REVIEW MEMBRANE TYPES AND CHEMISTRIES

§ REVIEW MARKET APPLICATIONS

§ PAY-OFF UNDERSTAND DIFFERENT MEMBRANE TYPES

§ ABILITY TO IDENTIFY MORE MEMBRANE APPLICATIONS

What are Membranes?

§ Thin barriers or films of material that allow certain substances to pass through.

§ Our bodies have numerous semi-permeable membranes that allow nutrients in and toxins out.

Semi-permeable membranes only allow some substances to pass through

Membrane Element

Construction

Materials of Construction

§ Organic– Cellulose Acetate– Thin Filmed Composite– Polypropylene– PVDF– Polyamide– PAN– PES

§ Inorganic– Ceramic– Metallic oxide/Stainless Steel– Zirconium oxide/Carbon

Materials of Construction

§ The material used in the construction have process limitations (pH, temperature etc.) These limitations will determine the type of applications the module can be applied.

§ Membranes are selected based on their compatibility to the stream they are treating.

Materials of Construction

§ Organic– Limited pH range for cleaning and operating

• varies from 2 to 12 for commercial membranes– Limited temperature range for cleaning and

operating• max 120 F for most commercial membranes

§ Inorganic– Wide pH operating and cleaning

• 1 - 14– High operating and cleaning Temperature

• 220 F

Materials of Construction

§ Organic– More commercially available– Lower replacement cost– Limited Life

§ Most applications where pH is less the 12 and greater then 2 and temperature is bellow 120O F.

Materials of Construction

§ Inorganic– Becoming more commercially available– High replacement cost– Easily cleaned– Theoretical Unlimited Life

§ Applications:– High or low pH less then 2 and greater the

12.– High temperature or steam sterilize

requirements

Membrane Element

Configurations

Flat Sheet Modules

Reverse Osmosis

– Food processing(old model)

Ultrafiltration

– Food processing– Immersed MBR

Advantage and Disadvantage of Flat sheet Construction

• Advantages- process high solids loading- good hydraulic flow behavior

• Disadvantages- not back flushable- low package density- difficult to clean.- limitation of plate size - sludge deposition at the boundary of plate

Hollow Fine Fiber Membranes

Microfiltration

Ultrafiltration

Seawater ROLarge strawsSmall straws Feed

Large fibers for microfiltration

Smaller fibers for UF & RO

UF in outor out in

Feed Product

Concentrate

RO out -in

Hollow Fiber Fine Membranes§ Advantages

– Very compact, limited floor space, high packing density.

– High permeate flows– Commercially available

§ Disadvantages– Modules are Susceptible to fouling– Effective cleaning is difficult (small spaces)– Difficult to detect membrane imperfections– Extensive pretreatment required– Viscous feed solutions containing high

concentrations of suspended solids tend to foul module and make it difficult to clean.

Hollow Fiber Applications

Reverse Osmosis

– Seawater desalinization(old model)

Ultrafiltration

– ED paint– Immersed MBR– Bacteria and Virus Removal– Immersed Drinking water

Permeate

Air

feed

Immersed Hollow Fiber For MBR

Tubular Membranes

Smallest pores

Membrane supportLarger pores

Feed

Product

Concentrate

Tubular Crossflow Velocity

Tubular Membranes

§ Advantages– Suitable configuration and chemistries for

wastewater– Easily cleaned by mechanical or hydraulic or

chemical procedures.– Multi-tube modules make it easy to replace

membranes– High Tolerance for Suspended solids– Commercially available

§ Disadvantages– High hold up volume– Membrane density low, Large floor area required– Pumping costs are high because of high fluid

velocities required.

Tubular Applications

Reverse Osmosis

– Specialty Food applications• Juice• Dairy

Ultrafiltration

– ED paint– External MBR– Oily wastewater– Juice Clarification– Inorganic precipitation processes (metals, softening)

– Textile wastewater

P e r m e a t e

F e e dp u m p

R e c i r c u l a t i o np u m p3 , 5 - 4 , 5 m / s

5 m

W a s t e w a t e r B e r g h o f F l o wB i o

B I O -R e a c t o r

Spiral Wound RO Module (Element)

Feedwater

Permeate flows spirally toward collection tube

Permeate Out

Concentrate

Concentrate

Permeate carrier

Feed flow across spacer

Covering & bypass spacer

Feed-channel spacer

Membranes

Perforated collection tube

Anti-telescopingdevice

Spiral Wound RO Flow Pattern

Spiral Wound Membranes

Advantages– High Packing Density– Module Hold-up volume is small– Modules easy to replace– Medium Range Tolerance for Suspended solids– Commercially available

Spiral Wound Membranes

Disadvantages

– Traditionally small flow channels are susceptible to fouling, new wide spacer configuration are now available.

– Dead end spaces make it difficult to clean– Membrane chemistry/glues/backing are limited– Not easily cleaned by hydraulic or chemical

procedures

Spiral Wound Applications

Reverse Osmosis/Nanofiltration

– Water Treatment• Demineralization Brackish and Seawater• Organics Removal –Nanofiltration

– Specialty Food applications• Juice• Dairy

– Wastewater– Metals concentration– Leachate– COD/BOD removal/polishing– Chemical Recovery

Spiral Wound Applications

Ultrafiltration

– Water Treatment• Polishing UF• Light Surface water

– Specialty Food applications• Juice• Dairy

– ED Paint

Hollow Fiber Capillary Membranes

Hollow Fiber Capillary Membranes

§ Advantages– Combine the benefits of both hollow fiber and

tubular configurations– Very compact, limited floor space, high packing

density.– High permeate flows– High solids loading– Commercially available– Backwash capability– Single chemistry, single structure, no delamination– Low energy

Hollow Fiber Capillary Membranes

§ Disadvantages– Modules are Susceptible to fouling with high solids

loading

Membrane Applications

– 3000 ppm of cutting fluid oils (20,000 gallons per day). Looking to reduce volume hauled away and to discharge permeate.

– Landfill leachate containing High TSS, Dissolved organics, COD and TDS that requires treatment prior to discharge.

– 2% Total solids of cheese whey. Looking to concentrate for animal feed and produce effluent of low BOD for discharge.

– Wastewater from existing biological treatment plant with clarifier, looking to reuse water back in manufacturing facility.

QUESTIONS

QUESTIONS?