© 2014 HDR, Inc., all rights reserved.

Peter D’Adamo, Ph.D., P.E.

Recent Advances in

Membrane Technologies2015 Spring Conference

Wilmington, NC

April 13, 2015

Membrane Filtration Basics

Operational Considerations

Conclusions

Recent Membrane Advances

Membrane Filtration Basics

Membranes vs. Granular Media

Membrane filtration mechanism

o Sieving/Straining

Granular media filtration mechanism

o Interception, collision, electrostatic

attraction

Membrane Classifications (Pore Size, microns)

Organic Macromolecules

Colloids

Bacteria Viruses Dissolved Salts

Yeasts

Microfiltration

Reverse OsmosisNanofiltration

Organic Compounds

1 0.1 0.01 0.001 0.000110

Visible to

naked eye

Red

globule

Smallest

microorganisms

Polio

virus

Ultrafiltration

Sand Filter

Cryptosporidium~

Vacuum (Submerged Membranes)

o Compatible with Higher Solid Concentration

o Can Be Used for Retrofit

o Higher Energy Demand with Air Scouring

o Noise, Corrosion & Evaporation Concerns

Membranes Classification(Driving Force)

Membranes Classification(Driving Force)

Pressure (Canister Membranes)

o More Compact Design

o High Solid Concentrations Problematic (> 100 NTU) for a Substantial Period of

Time

Polymeric Material (polyethersulfone (PES) or polyvinylidene

difluoride (PVDF), others)

Hollow Fiber Membranes (ID < 1.5 mm)

Membranes Classification(Configuration)

Mostly used in MF & UF

Operational Considerations

Cleaning

Flux

Typical Pressure MF/UF System

Air System B/W Water

Cl2

Raw

Water

Source

Supply

Pump

Particle

Strainer

CIP System

Membrane

Modules Backwash Waste/

Concentrate

To Disposal

Finished

Water

Storage

Finished

Water

Pumping

Permeate

Pretreatment

Submerged - Enhanced Coagulation

Air

PermeatePump

Feed Water

Bleed/Concentrate

FlocculationChamber

Coagulant

Flash Mixer

Pre-

treatment

CIP System

Key Membrane Terminology

Flux – Flow across Membrane (gallons/SF/Day, GFD)

Temperature Corrected Flux (Standard – 20-degree C)

Transmembrane Pressure – Water Pressure Change across

Membrane, TMP)

Specific Flux – Flux/TMP

Specific Permeability – Filtrate flow/(membrane area * TMP)

Integrity Testing (Pressure Decay Test, Bubble Point Test)

LRV – Log Removal Value

Membrane Cleaning

Water/Air Backwash

Air Scouring

Water Flushing

Hypochlorite and Citric Acid

Acid/Base

Proprietary Chemicals

(surfactants)

Hydraulic Cleaning

(every 15 to 45 minutes)

Clean-in-Place

(every 4 to 8 weeks)

Maintenance Wash

(every 12 to 48 hours)

Hypochlorite or citric acid

Chemical recirculation

Water Flushing

Membrane Fouling

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250 300

Time

Pre

ssu

re -

psi

Membrane

Fouling

Backwash

Irreversable

Fouling

Backwash &

Chemical Cleaning

Recent Membrane Advances

When will fibers break?o During shipment, installation,

o start-up and operation

Why will fibers break?o Fibers dried out

o Mechanical abrasion

o Embrittlement

o Abrading each other

o Debris (raw water or backwash

water)

o Poor quality

Membrane Fiber Breakage Management

Changes to Membrane Designs

Materials of construction

Configuration

Materials of Construction (Polymeric) Polymeric membraneso Improved chemistry for slightly better chemical resistance

o Enhanced permeability

o Larger diameter fibers with thicker walls to resist fiber breakage

o Some vendors have changed potting materials

Common Municipal

Membrane Vendors Recent Changes

Pall Microza None really

GE Zenon Thicker fibers for ZW-1000

New modules for ZW-1500 system

Evoqua (Siemens) Memcor N

Modules

Thicker fibers

New potting materials

Advancements in Permeability and Abrasion Resistance

Research shows membrane permeability of a membrane fiber directly correlates to

abrasion resistance of the membrane fiber

• Evoqua N Fiber after 1

month of harsh,

accelerated abrasion

testing

• Little visible evidence to

suggest degradation

Improved Fiber Morphology Drives System Improvements

Yuba City Water Treatment Plant - First Two Years of Operation Summary

Membrane permeability remained high

Treated water quality was excellent

Pressure decay test values began to

rise and log removal values fell

Membrane integrity issues became a

concern and Memcor was contacted

Memcor began pilot testing in 2010 to

gain understanding of problem

Pilot Testing Summary

Pilot testing of the originally installed S10V modules conducted August

2010 through June 2011

Pilot unit experienced same integrity issues as the full scale system

Cause identified as abrasion of the fibers by small particles such as

diatoms, which compromised the outer surface of the fibers

Pilot testing of the new S10N UF modules conducted August 2011

through June 2012

Pilot unit modules showed dramatic improvement in integrity

TMP remained low and permeability high throughout the test period

Pilot Testing Results for N Module at Yuba City

Integrity Testing Results for N Module at Yuba City

…And with the Resulting Permeability Enhancement a Reduction in Pumping Requirements

inge Multibore Membranes

Polymeric MF membranes with large, multiple

lumens in one “fiber”

Improved physical strength (no fiber breakage)

Tolerate high turbidity

What are Ceramic Membranes?

Aluminum oxide porous base material

Often used for difficult industrial

applications

System for potable water developed by

NGK, Japan in 1990s

Very expensive but nearly indestructible

o Less pre-treatment requirements

o pH, oxidant resistant

Very low O&M costs

o Membranes last 50+ years

Ceramic versus Polymeric

Variable Ceramic Polymeric

Flux (gfd) 100 - 220 30 - 85

Turbidity (NTU) < 1,500 <100

TSS (mg/L) < 3,000 < 200

TOC/DOC (mg/L) < 100 < 30

Coagulant (mg/L) < 200 < 30

Recovery (%) > 98 > 96

Filtration Interval (hrs) 1 - 2 0.25 – 0.67

CEB Interval (day) 2 – 4 1

CIP Interval (month) 6 1

Monolith1,000’s

of HF

lumens

Ceramic Membrane process train requires less pretreatment

ClO2 or

KMNO4

Chlorine

Deer

Creek

PS

Influent Tank

(Aeration/PAC)

PAC

Flocculation

Coagulant

Effluent

GAC

UV

(Future)

Clearwell

Ceramic

Membranes

BWW

Ceramic Membranes are Robust and Becoming more Cost Effective

• Ability to handle high turbidity, PAC and

coagulants

• 20-year membrane warranty

• New Dutch design improves economics

35

Membrane Pre-Selection Procurement Bid Tabs

Line Item Costs by Membrane

Manufacturer Pal

l

Kru

ger

Sie

men

s

Total Membrane System Capital Cost$1,383,828 $3,088,188 $1,172,569

Total Membrane Plus Pretreatment Capital Cost (Tax

Included)$2,078,658 $3,170,125 $1,867,399

Total of Annual Operating Costs (Present Worth)$1,729,076 $737,577 $1,667,222

20-Year Present Worth of Annual Cost For Membrane

Replacement$260,211 $265,139 $516,072

Pretreatment Present Worth O&M Total$493,206 $362,067 $499,461

20-Year Present Worth Total$4,561,150 $4,534,908 $4,550,154

Take Away Points

Membranes Offers a Wide Range of Applications

Membrane is a Mature Technology but New Advances Every

Year

Industry Moving more Towards Plug and Play

A Successful Membrane Operation Depends on

oThe Selection of an Appropriate System

oProper Pretreatment for water supply and technology

© 2014 HDR Architecture, Inc., all rights reserved.© 2014 HDR Architecture, Inc., all rights reserved.© 2014 HDR Architecture, Inc., all rights reserved.© 2014 HDR, Inc., all rights reserved.© 2014 HDR, Inc., all rights reserved.© 2014 HDR, Inc., all rights reserved.© 2014 HDR, Inc., all rights reserved.

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