future of membrane technologies for wastewater...

Future of Membrane Technologies

for Wastewater Treatment

Seungkwan Hong

School of Civil, Environmental & Architectural Engineering, Korea University

Joon Ha Kim

School of Environmental Science & Engineering, GIST, Korea

Process Intensification by New Membranes

Source Water Integration by Membrane Process

New Paradigm for Water Supply: Challenging

with Membranes

WEPE Water Environment Plant Engineering Lab.

Climate Change & Water Shortage

Localized water shortage problem

is expected to get worse due to global worming

http://upload.wikimedia.org/wikipedia/commons/f/f4/Instrumental_Temperature_Record.png


Paradigm Shift in Water Management

Water Cultivation

Source Source Source

Extraction &

Treatment

Consumption

Water

Reclamation

Water Hunting

Source

Wastewater

Treatment

Loss

Loss

Loss

Loss

Extraction &

Treatment

http://www.clipartof.com/details/clipart/4271.html


Needs for Membrane Technology

Water shortage caused by global warming

Stricter water quality

Deteriorating water supply system

Securing alternative water resources

Higher removal

Smart water system

2010 1996

1.25

0.25

0.75

Co

st

of

Wa

ter

$/m

3

Cost of Water Reuse

Cost of Desalination

0.50

1.00

(1st Singapore Desalination and Water Reuse Leadership Summit, 2007)

Two ways for developing alternative water resource

Wastewater reuse

Desalination

Augmenting water resources using

State-of-art membrane process


Small footprint

Less sludge

High potential of integrating with various processes

Less chemicals

Membrane Technology for Decentralized Reuse Systems

Easy automation

(Source: Overview of Water Reuse Technology, LeChevallier)

Decentralized Reuse


Secondary treatment

Pre- treatment

Activated sludge C, N (P)

Clarification

2+3 MBR

Pre- treatment

MBR C, N-DN

Tertiary treatment

Conventional process

Submerged membranes

External membranes

UF / MF Disinfection Cl / UV / O3

Filtration

UF / MF

Disinfection Cl / UV / O3

Quaternary treatment

Reverse Osmosis

Brine

Membrane Applications for Water Reuse

(Source: Lazarova, Suez, France)

Filtration

Disinfection Cl / UV / O3

Typical Wastewater Reclamation Processes


MBR Process

MBR Process (Membrane Bio-reactor)

Biological Treatment (Biological Reaction)

Membrane Separation

Reducing HRT

Reducing yield of sludge (50%)

Better N removal

Managing shock load and raw water variation

Maintaining high MLSS

Complete removal of SS, e-coli (unnecessary disinfection)

Satisfying regulation for organic concentration (reclaimed

water etc.)

Stable water quality

Eliminating sedimentation-related problems

Compactness and easy automatic operation (remote diagnosis,

remote control etc.)

Simple design: manufacturing and installing as package

Easy management

Membrane fouling (pore clogging: etc)

Phosphorus removal (related with sludge)

Sludge disposal problem when small-scale, multi facilities are

operated

Operational Problems

Advantage Disadvantage


Recent Trend of MBR

Papers related with MBR increased steadily 20% per year (1990~2009)

(Source: Santos et al., Desalination, 2011)

Development of industrial and municipal MBR markets (402 references)

(Lesjean, “Survey of the European MBR market: trends and perspectives”, Desalination, 2008)

MBR installations increased significantly in the last decade


Permeate P

Suction Pump

Air

Wasting

Wastewate

r

Chemical

Blower

MBR Process for Biological Nutrient Removal

Permeate P Suction Pump

Air

Sludge T/K P P

Sludge Pump

Recycle

Dewatering

Final Disposal

Anoxic Aerobic

Wasting

Alum


(Source: Kolon, KIMAS, 2011)

Stabilizing basin

Anoxic

basin

Anaerobic

basin

Aerobic

basin

Memb. basin Influent

Step feed Internal recycle

Alum

(Conditional) Memb. Cleaning Air Process Air

Excess sludge

Effluent

Screen

• Minimize DO leaking into anoxic basin, which is helpful for

efficient denitrification in anoxic basin

• Anoxic basin is placed prior to anaerobic basin due to remove nitrogen more than

phosphorus

- To use organics for nitrogen removal (appropriate for low C/N influent and long SRT

operation)

- To minimize inhibition of phosphorus release in anaerobic basin by removing NO3-N in

anoxic basin

• Reduce air supply by dividing aerobic zone

- Aerobic basin: fine bubble

- Membrane basin: Coarse bubble

• External submersed MBR

Improvements of MBR Process


Year 1990 ~ 1996 ~ 2000 ~ 2006 ~

Nitrogen Removal

- (1 tank)

Inner return (2 tank)

Inner return (3 tank)

Inner return (3-4 tank)

HRT 10 hr 10 hr 6~9 hr 4~6 hr

MLSS 15-20k 12k 10k 5k~10k

SRT 75d 60d 25~40d 10~25d

Flux 0.4-0.6 m/d 0.8 m/d 0.6~0.8 m/d 0.6~ 0.9 m/d

Significance High flux Optimization P. removal

Large scale

Improving MBR in Last 20years


0

SS

BOD

Fiber (pressure) - treated water - sewage

1 10 10

0

1K 10k 100k

1

10

10

0

1K

10k

100k

Flat/Fiber

- sewage - Industrial wastewater - sludge

Tubular (pressure) - Industrial wastewater - livestock wastewater

1st Generation

2nd Generation

3rd Generation(?)

Materials PP / PE / PE / PES / PAN etc.

PVDF PTFE

Temperature Low ~ Mid Mid ~ High High

Chemical Resistance

Low Mid ~ High High

Durability Low ~ Mid Mid ~ High High

Economic Value*

Low ~ Mid

Mid ~ High High

Applicability of MBR

Mid High High

* Economic Value : (membrane price / membrane life)

Membrane Configurations and Materials

Various membrane modules and configurations have been installed depending on wastewater quality (no standardization)

PVDF is a major product in the current market


FILMTEC developed/applied membrane module

1949 UCLA group started

membrane process

Hassler proposed

synthetic multi layer film

1940 1950 1960 1970 1980 1990 2000 2010

UCLA: developed

1000 psi->0.2 GFD capacity membrane

U Florida applied Cellulose

Acetate membrane to RO

Loeb and Sourirajan developed Asymmetric RO

(1962)

Constructed the first desalination

plant 20 m3/day

Thin-film composite (TFC) membrane

developed

Constructed the first grand scale

desalination plant 1000 m3/day

Much larger plant ~36,000 m3/day

GrahamTek developded Larger module

Tempa Bay Desal. Plant

Reverse Osmosis Technologies

Cellulose Alphatic Polyamide

Aromatic Polyamide

(Henmi, IDA 2009)

Significant improvement over last 50 years



New Paradigm for Water Supply: Challenging with

Membranes


Process Intensification

Improvement of membrane process

Process Intensification is a solution for sustainable development of water and energy.

Using much less ! Produce much more !!


Integration of membrane technology

New membrane modules & materials

Optimization of system design

Novel concentration treatment options

Development of systems coupled with renewable energy sources

Reconsideration of FO, PRO & reverse electrodialysis

Key Factors

Process Intensification

(Source: Drioli, Recent Progresses and Perspectives in Desalination with Integrated Membrane Systems, 2010, Korea)


Improvement by Process Intensification

Improving MBR Process

MBR + BNR

- Increasing removal efficiency of N, P

AnMBR (anaerobic MBR)

- Low energy demand compared to aerobic process

- Improving process efficiency through methane gas reuse

HR(high retention)-MBR

- Increasing removal efficiency of BOD and TSS

- Using NF, FO, MD


Fouling Assessment for the Future:

More Direct

Direct Measurement of Membrane-foulant Interactions by Atomic force microscopy

More Microscopic

Characterization of RO Membrane Surface Heterogeneity by Dynamic Hysteresis

Fouling in MBR : Measurements and Minimization

MBR processes, both aerobic and anaerobic, suffered from membrane fouling Great efforts have been made in both fundamental and applied researches in the last decades

(Source: Meng et al., Review: Recent advances in

MBR, Water Research, 2009)


Direct Measurement by AFM

(a)• Initial fouling behaviour associated with membrane-foulant

interaction was investigated by atomic force microscopy

(AFM) for various RO membranes with different surface

properties.

• Carboxylate modified latex (CML) and unmodified latex

particles were used as surrogates of organic foulants to

simulate functional groups of typical organic substances

Accumulated Volume (L)

0 50 100 150 200

No

rma

lize

d S

pe

cif

ic F

lux

(N

SF

)

0.75

0.80

0.85

0.90

0.95

1.00TM-820

SWC-5

SW-30HR

Initial fouling rate showed fairly good correlation with adhesion force measured by AFM

TM-820 SWC-5 SW-30HR

F/R

(mN

/m)

0

1

2

3

4

Source: Yang et al., ”Role of foulant-membrane interactions in organic fouling of RO membranes with respect to membrane properties”, Separation Science and Technology, (2010)


Dynamic Hysteresis = FA - FR

FA = FR Dynamic Hysteresis =0

Homogeneous

surface

Principle of Dynamic Hysteresis

Flu

x r

eduction (

%)

SWC-5

TM-820

RE-8040

SW-30HR

R2 = 0.8761

Dynamic hysteresis (mN/m)

Sangyoup Lee, Eunsu Lee, Menachem Elimelech, Seungkwan Hong, “Membrane characterization by dynamic hysteresis: Measurements, mechanisms, and implications for membrane fouling”, Journal of Membrane Science, 366, (2011) 17-24

Physical/Chemical Heterogeneity by DH


Dynamic hysteresis

Heterogeneous roughness/charge

distribution

Bacterial deposition

Increase

in

+

+

─ +

+

Concept of DH to Membrane Fouling

(Source: Kim et al., Water Science & Technology)


(Source: Yeon et al., Quorum sensing : a new biofouling control paradigm in membrane bioreactor for advanced wastewater treatment. Environmental Science and Technology, 2009)

Fouling Control by Quorum Sensing

Physical/chemical methods to control biofouling have been applied extensively but theirs effects are rather limited New biological method to minimize biofouling: microbial growth inhibition by Quorum Sensing


Using principle of forward osmosis

FO membrane acts as a barrier to solute transport and provides high

rejection of the contaminants in the wastewater stream.

Introduction

Osmotic MBR

Disinfection

Wastewater

Potable

Water

Sludge

RO or NF

Draw Solution Recovery Process

Concentrated Draw Solution

(Salt)

Diluted Draw Solution


The main problem associated with MBRs is membrane fouling

FO is likely to have lower fouling propensity

Compared to the MF or UF, FO-MBR offers the advantages of much higher

rejection.

The high rejection by FO may lead to better fouling control in RO and

higher quality RO product water.

Advantage of FO-MBR

Obstacles of FO-MBR

Lack of economically feasible DS (draw solution)

Reverse salt transport from the DS not only results in an reduced driving

force, but may also have inhibitory or toxic-effects on the microbial

community inside the reactor.


Recent Studies

Cornelissen et al.

(2008)

Achilli et al.

(2009)

Lay et al.

(2011)

Configuration Batch Continuous flow

Submerged

Continuous flow

Submerged

Draw solution NaCl, MgSO4, etc NaCl NaCl

Membrane CTA (HTI) CTA (HTI) CTA (HTI)

Cross flow rate - 1.5 LPM 0.5 LPM

Temperature 20±1℃ 23±1℃ 20-22℃

SRT or HRT - HRT 3.5 days

SRT 15 days

HRT varied

SRT 20 days

Membrane CTA (HTI) CTA (HTI) CTA (HTI)

Flux 6.2 LMH

(1.5 M NaCl)

9 LMH

(50 g NaCl/L)

2.7 LMH

(0.5 mol/kg NaCl)

Fouling No reversible nor

irreversible

Reversible 10%

Irreversible 10% Mild fouling

Rejection 98 % 99% (TOC) -

Reverse diffusion 3.7 g/m2h 7.7 g/m2h (new)

6.4 g/m2h (used) -


200 300 400 500 600 7000.0

2.0

4.0

6.0

8.0

RO (P = 450 psi)

FO (Draw solution = 5 M NaCl)

Flu

x (m

/s)

Time (min)

200 300 400 500 600 7000.0

2.0

4.0

6.0

8.0

RO (P = 450 psi)

FO (Draw solution = 5 M NaCl)

Flu

x (m

/s)

Time (min)

Alginate (200 mg/L) Humic acid (200 mg/L)

Organic Fouling

Under identical physicochemical conditions,

more flux decline is observed in FO mode compared to RO mode


CEOP by Salt Reverse Diffusion

CP Profile

Fouling

Layer

)( PAJw

πdraw- πfeed

Increase

salt

Reverse

Diffusion AJwDecrease

CEOP:

Cake-Enhanced Osmotic Pressure

Draw side Feed side

Source: Sangyoup Lee, Chanhee Boo, Menachem Elimelech, Seungkwan Hong, Comparison of Fouling

Behaviors between Forward Osmosis (FO) and Reverse Osmosis (RO), Journal of Membrane Science (2010)


Effect of Draw Solution

500 1000 1500 20000.0

1.0

2.0

3.0

4.0

RO (180 psi)

FO (0.6 M NaCl)

Flu

x (m

/s)

Time (min)

FO (3 M Dextrose)

Alginate (200 mg/L)


Fouling Reversibility in FO

0 200 400 600 8000.0

2.0

4.0

6.0

8.0

10.0

Draw solution: 5.0 M NaCl

UXF

= 8.54 -> 26.6 cm/s

Alginate = 200 mg/L

IS = 50 mM (Ca2+

= 1.0 mM)

Flu

x (m

/s)

Time (min)

UXF

= 34.0 cm/s

UXF

= 25.5 cm/s

UXF

= 17.0 cm/s

300 600 900 12000.0

2.0

4.0

6.0

8.0

UXF

= 8.54 cm/s

UXF

= 26.6 cm/s

Alginate = 200 mg/L

IS = 50 mM

Ca2+

= 1 mM

RO (450 psi)

FO (5 M NaCl)

Flu

x (m

/s)

Time (min)


Using principle of distillation

Both heated mixed liquor and cooled permeate

steams are in direct contact with the membrane

MD-MBR takes place at atmospheric pressure and at

temperature 45-80℃, in which the thermophilic

bacteria can survive

Introduction

(Source: Khaing et al. S&PT74(2010))

Warm

Feed

Cool

Permeate

Vapor

Space

Evap

ora

tio

n

Co

nd

en

sati

on

Hydrophobic Microporous

Membrane (PVDF,PTFE)


Advantages of MD-MBR

Characteristic MF/UF-MBR MDBR

Driving force Pressure (suction preferred) Thermal (temperature difference), at atmospheric pressure

Membrane UF or MF, hydrophilic Porous, hydrophobic MF

Phase in membrane pores

Liquid Vapor (gas)

Retention Incomplete 100% for salts, non-volatile organic compounds, and microorganisms

Permeate quality Dependent on biological activity; TOC of 3-10 ppm

Independent of biological activity, TOC < 0.8 ppm

Inorganics Salts not retained Salts retained and discharged with waste sludge

Organic and hydraulic retention time

ORT ~ HRT ORT ~ ∞, independent of HRT

FLUX 10~30 L/m2h (typically) 2~15 L/m2h at 55 ℃

Membrane integrity monitoring

Particle counting techniques, pressure decay tests

Conductivity monitoring on continuous basis

(Source: Phattaranawik et al., A novel membrane bioreactor based on membrane distillation, Desalination (2008))

A potentially efficient and reliable process for separating high quality product water from

mixed liquor in the bioreactor

Complete retentions of non-volatile organics

The permeate quality is independent of the biological activity of the bioreactor

Obstacles of MDBR

Energy cost must

be solved

regarding both

heating and

cooling



New Paradigm for Water Supply: Challenging with

Membranes


Key Word for the Future

(Source: Kurihara, IDA Tianjin 2011)

Integration Technology

(Hybrid)

Less Energy

Consumption

Integrated membrane system project (Japan, NEDO) Utilizing seawater desalination and wastewater reclamation technologies


Limitation of Reverse Osmosis

Minimum theoretical energy for desalination

at 50% recovery: 1 kWh/m3

Practical limitations: No less than 1.5 kWh/m3

Achievable goal: 1.5 2 kWh/m3

[Developments of SWRO]

12

8

5 4

2~2.5

kWh/m3

1970 1980 1990 2000 2010

(2007 AMTA)

• High Efficiency Pump

• Energy Recovery Device

• High Performance Membrane and Module

(Source: Shannon et al., Nature (2008))

External energy


1970

2.5

3.5

4.9

8

20

1980

1990

2000

2010

Next

Power Consumption (KWh/m3)

Development of Cellulose Acetate (CA)

membrane (1960s ~ 1970s)

Development of Thin-film composite (TFC)

polyamide (PA) membrane (1980s ~ 2000)

Improvement of energy efficiency by HER

(hydraulic energy recovery) develpments

(2000 ~ 2010)

Improvement of energy efficiency by OER

(osmotic energy recovery) (2010 ~ )

Historical improvement of RO systems

Reducing Energy for Seawater Desalination using Reverse Osmosis


The seawater (SW) is diluted with forward osmosis (FO) by taking water from an impaired source (wastewater, effluents from WWTP). Coastal cities with water shortage problems can acquire water from wastewater by using SW as draw solution.

Sea water

1st stage

FO

Reclaimed

water

RO

Purified

Water

2nd stage

FO

Concentrated

brine

Discharged

to Sea water

Dilution of Feed

to RO stage

(△Π decrease)

Water Reclamation with Hybrid O/RO


New Concept

Multiple barriers to reject potential contaminants

Energy Demand

FO/RO System

Water Quality

Membrane Fouling

Advantages of hybrid FO/RO

Less Fouling with Waste Streams of high fouling propensity.

Osmotic energy of the saline stream used as a driving force


Pressure-retarded Osmosis (PRO)

Reverse Osmosis

Separation Booster

Pump

High pressure

P 〉 △π Low pressure

P 〈 △π

Low Energy Energy Generation

Semi-

permeable

membrane

Water Flows

by Natural

Osmosis

Forward Osmosis Pressure-retarded Osmosis


Integration with MBR Process

Sea water Wastewater

DMF

MBR

SWRO

BWRO Purified

Water

PRO

Concentrated

brine

Treated Wastewater

IWA Regional Conference and Exhibition, Turkey, 2010, Childress


Economic feasibility

5-7 W/m2

Power Density of PRO Membrane

: Draw solution having seawater concentration

: Draw solution having a higher concentration of seawater

IWA Regional Conference and Exhibition, Turkey, 2010, Childress

Pressure-Retarded Osmosis (PRO)


Rainfall data, Assuming initial tank size

Calculate discharge Volume

(Rainfall depth × Area × Run-off coefficient)

Discharge Volume ≥ Tank size Discharge Volume < Tank size

Inflow Volume = Tank size Inflow Volume = Discharge Volume

Calculate storage Volume

(Storage Vol = Inflow Vol + Residual storage Vol - Usage

Vol)

Storage Volume ≥ 0 Storage Volume < 0

END

(Adopts tank size) Increase tank size

&

Recalculate storage Volume

Roof Area : 150 m2

Run-off Coefficient : 0.8

Daily Usage Volume : 0.1 m3

Rainfall Data (Daily) :

Seoul, 1991 ~ 2000 (3650 days)

The actual daily rainfall data of the city of

Seoul were obtained for the 10 years of

period (3650 days)

In order to determine the tank size for

rainwater harvesting, the simulation was

performed using 10 years of rainfall data

collected.

Integration of Wastewater Reclamation with Rainwater Harvesting


Time (day)

0 365 730 1095 1460 1825 2190 2555 2920 3285 3650

Rai

nwat

er T

ank

(m3 )

0

2

4

6

8

109.6 m3

In order to supply daily 0.1 m3 of rainwater continuously for 10 years,

9.6 m3 of rainwater tank is required, which is 96 times more than

daily supply (0.1 m3) : Over-sizing storage tank.

Rainwater tank size was determined by the winter season(dec-feb)

Sizing Rainwater Collection Tank


Sizing Rainwater Collection Tank

using 0.1 m3/day

Tank size (ton)

0 2 4 6 8 10

Days

of

us

ing

ra

inw

ate

r

0

1000

2000

3000

4000

100 %

80 %

1.4 9.6

• Instead of relying on rainwater (100 %), if only 80 % of

daily water supply is coming from rainwater harvesting,

the tank size can be reduced form 9.6 ton to 1.4 ton.

• Thus, additional water resources are needed → integration

with water reuse system.


Hybrid-MBR with Rainwater Harvesting

Membrae module

Effluent (1)

Waste

Pump

Backwash Pump

Cross-flow LPRO

Effluent (2)

Blending

Aeration

Tank

Rainwater

Storage

Wastewater

• Operating Concept of rainwater harvesting and water reuse

No Rainfall Rainfall

Treat rainwater using

membrane module

directly

Treat wastewater using

bioreactor - membrane

module.

Blending treated waste water with

Stored rainwater to meet different

Final water quality.

Rainwater


Lab-scale Experiment Results

Parameter Toilet water Sprinkling Gardening

water Car washing MBR Effluent

Accept/

not accept

Residual

chlorine > 0.2mg/L > 0.2mg/L - > 0.2mg/L Not dectect O

Appearance Not feel

unpleasant

Not feel

unpleasant

Not feel

unpleasant

Not feel

unpleasant

Not feel

unpleasant O

Turbidity < 5 NTU < 5 NTU < 5 NTU < 5 NTU 0.9 O

BOD < 10mg/L < 10mg/L < 10mg/L < 10mg/L 1.2 O

Smell Pleasant

smell

Pleasant

smell

Pleasant

smell

Pleasant

smell

Pleasant

smell O

pH 5.8~8.5 5.8~8.5 5.8~8.5 5.8~8.5 6.5 O

Color < 20 - - < 20mg/L 33 X

CODmn < 20mg/L < 20mg/L < 20mg/L < 20mg/L O

• Most of effluent quality parameters satisfied wastewater reuse standard

in Korea except color

• Post treatment was required to lower effluent color


Col

or

0

10

20

30

Eff

icie

ncy

(%)

0

20

40

60

80

100

Influent Concentration

Effluent Concentration

Removal rate

GAC RO Ozone Ozone-GAC

RO exhibited the best Color removal

efficiency, following by Ozone

combined with GAC, Ozone and GAC

adsorption.

Blending Ratio

100/0 75/25 50/50 25/75 0/100

Co

lor

0

5

10

15

20

25

30

35

Color

To satisfy the requirements of

color for water reuse without

expensive post-treatment processes,

50:50 blending was desirable.

Blending of Treated Wastewater and Collected Rainwater


Poor Water

Quality

Less storage

Tank

Waste Water

Rain Water

Constant Water

Quantity

Less post treatment

Good Water

Quality

Unstable Water

Quantity

Integrating MBR system with rainwater harvesting can decrease

the cost of water supply by reducing the size of rainwater storage tank as

well as making expensive post treatment process unnecessary.

Integration of Wastewater Reclamation with Rainwater Harvesting


Smart Water Grid

Target water quality (due to processing

and distribution facility) diversification

• WTP

• Used Water Treatment Plant

• WWTP

• Small plant using rain water

Demanding Diversification as Water

Quantity and Quality

• High Quality, High Price

• Low Quality, Low Price

• Mid Quality, Mid Price

Decentralized Water

Treatment Plant

Water Control Center

Industry

Housing

Rainwater, Storage and using system

Smart Sensor Network

Automatic, Intelligent, Remote

management System.

Business

Smart Water Grid System

(Decentralized Water System)

• A smart water grid system delivers water from suppliers to consumers with two-way communications.

• Reducing water supply cost and thus increasing reliability.

• The water distribution grid with information and metering systems

http://images.google.co.kr/imgres?imgurl=http://img.diytrade.com/cdimg/465342/6751936/0/1244001561/Industrial_RO_water_treatment_30Ton_H.jpg&imgrefurl=http://www.diytrade.com/china/4/leads/4537178/Industrial_RO_water_treatment_30Ton_H.html&usg=__sXF6GRfy9f8iSpIKxMFLgrm46SE=&h=637&w=1000&sz=133&hl=ko&start=120&sig2=BgRP-Z6PFphuj57Sxgy6pg&um=1&tbnid=5voBXny0MzepJM:&tbnh=95&tbnw=149&prev=/images?q=industrial+water&ndsp=18&hl=ko&rlz=1T4GGLL_koKR303KR304&sa=N&start=108&um=1&newwindow=1&ei=GSOJSrOIHcqXkQXK2_DIBw


Chemical Energy

Gasoline Car

Conventional

Treatment

Electric Energy

Electric Car

Advanced

Treatment

Smart Power Grid-Water Gird : Water and Energy Nexus

Water and Energy


Water Quality Managements in SWG

Water Quality Parameter G1 S1 RO Alkalinity (mg/L as CaCO3) 207 60 69

pH 7.87 7.92 8.06

Chloride (mg/L) 28.9 37.1 91.7

Sulfate (mg/L) 26.1 190.2 5.8

Sodium (mg/L) 18.0 48.7 52.3

Calcium (mg/L) 84.8 56.5 28.7

SiO2 (mg/L) 13.7 10.0 3.5

TDS (mg/L) 421 423 267

Dissolved Oxygen (mg/L) 6.53 6.31 5.15

Temperature (oC) 24.2 24.0 24.1

UV-254 (cm-1) 0.060 0.024 0.028

G1: Conventional ground water treated by aeration

S1: Surface water treated by enhanced ferric sulfate coagulation

RO: Saline water desalted by RO membrane

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

12/29/01 03/19/02 06/07/02 08/26/02 11/14/02

Experiment Duration (date)

To

tal

Iro

n R

ele

ase (

mg

/L)

G1

S1

RO

Effect of Source Water Blending on

Corrosion, Tampa, Florida

Zhijian Tang, Seungkwan Hong, Weizhong Xiao and James Taylor, “Characteristics of Iron Corrosion Scales Established under Blending of

Ground, Surface, and Saline Waters and Their Impacts on Iron Release in the Pipe Distribution System”, Corrosion Science, Vol.48 (2006)

322-342


Acknowledgement

경청해 주셔서 감사합니다. Thanks for your attention

future of membrane technologies for wastewater...

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