membranes for water recylcing - t walker

8/13/2019 Membranes for Water Recylcing - T Walker

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2Agenda

Introduction

Membrane Types

Microfiltration/Ultrafiltration

Introduction to the Technology

Design Issues

Membrane Bioreactors

Particular Application of UF/MF

Reverse Osmosis

Also a membrane technology

Complemented by UF/MF

Case Studies

Design Issues

Costs


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3

Case Studies

11 Membranes in Reuse


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4Australia Growth in water reuse

Reuse Market Research - Cumulative Flow for Australia

Veolia Water and Wanwick PAM 2002 data

0

50

100

150

200

250

300

350

400

450

1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Flow

(1000m3/d)

Average Grow th Rate - 41.2%

Growth from 1995 to 2003

390 Ml/d = US$ 250 -350 Million

or an average of

US$ 30 - 45 Million each year

41%

growth

per year


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5Membrane Wastewater Reuse Options

Primary Treatment

Biological Treatment

Micro/Ultrafiltration

Municipal Sewage

Membrane Bioreactor

Reverse Osmosis

High Quality Irrigation (playing field, golf courses)Low Grade Industrial

High Quality IndustrialPotable (Direct & Indirect)


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6Membrane Separation Where do they fit?


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7

Case Studies22 Microfiltration/Ultrafiltration


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8Micro/Ultrafiltration - Barrier filtration

Contaminants accumulateon outer wall of the fibre

Feed stream

Filtrate

Membrane wall


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9High Degree Of Removal

Giardia and Cryptosporidium cysts are manytimes larger than membrane sub-micron pore size

3 - 14microns

Sub-micron

Pore size

Low turbidity/SS regardless of feed solidsRemoves parasites (crypto & giardia)


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10Modules or Cassettes

Zenon (Zeeweed)

Memcor (CMF/CMF-s)

Norit X-Flow


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11Rack Assembly/ Cassette Assembly


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13Filtration cycle Managing Solids

Start filtration

FLOWFLOW

End filtration

FLOWFLOW


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14Filtration cycle Managing Solids

Start filtration

FLOWFLOW

End filtration

FLOWFLOW

Feed concentration

constant @ raw

water concentration


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15

AIR

SCOUR

AIR

SCOUR

Backwash cycle Managing Solids


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16

AIR

SCOUR

AIR

SCOUR

FILTRATE BACKWASHFILTRATE BACKWASH

Backwash cycle Managing Solids


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17Filtration cycle

Start filtration

FLOWFLOW

End filtration

FLOWFLOW

Start filtration

FLOWFLOW


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18Maintaining Filtration Rates - Backwash & Cleaning

Membr

aneDP

Time

Backwash

Chemical Clean


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19What Makes Up the System?

Feed Strainers

Backwash

Prescreening

InletWater

Microfiltration

Air Blowers

Blowers

Filtrate Pumps

1mm Strainer MeshSelf Backwashing

VSD for flow control/power savingsLow NPSH (if suction application) toimprove operating windowInternals compatible with cleaningchemicalsFiltration pump also often used forbackwash flows.

Careful attention to turndown requirements.

Cleaning System


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20

Air

Pressure100kPa

Air flow bydiffusion

DefectAir flowthrough defect

Membrane Barrier Test The Integrity Test

( )defectthroughairQf

time

P__

=

PDT

Much MoreSensitive Than

Turbidity orParticle Counting


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21

Market Growth

1994 250 plants 0.2 ML/day Av.

2003 >1000 plants >3 ML/day Av.

0

500

1000

1500

2000

InstalledML/day

1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Nett Installed MF Capacity

MF/UF Improvements - Market Growth


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22

10

100

1,000

10,000

100 1,000 10,000 100,000 1,000,000

Cumulative membrane area - metres

Processcost-$/kL/dayinstalled

1988 1991 1994 1997 2000

Declining MF Membrane Cost


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23

Membranes

Chlorine Resistance

Higher flows Lower costs

Configurations

Pressurised Submerged Lower costs, bigger flows,

smaller area

MF Membrane and System Improvements


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24MBR (Membrane Bioreactors)

Application of UF/MFMembranes

North Head (Sydney Water, CH2MHill, Memcor)


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25MBR = Activated Sludge + Membrane Filtration

Reduced footprint


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26Treatment Objectives

As a biological process

As a membrane process

Carbon removal

Nitrogen removal

Physical-chemical P-removal

Total retention of TSS

Disinfection (up to log 4 removal of viruses)

Improvement of carbon and P removal (higherretention of particulates)

VWS2


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27Cassettes, Modules or Flat Sheets

VWS2


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Slide 27

VWS2 Add in a picture of Toray or Puron Flat Sheet Membranes.Veolia Water Systems, 6/06/2006


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28MBR - Advantages

Reduced Plant Footprint (no clarfiers or sand filters)

Not reliant on sludge settleability

Designed with long sludge age, less sludge waste production

MF/UF Quality effluent

Plant can be housed in small building reduces noise, neighbourissues.

Perthes et Gatais - France


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29MBR World References

Steven Chapman et al, Membrane Bioreactors for Municipal Wastewater Treatment An AustralianPerspective. Enviro 05


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30MBR Australian References


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31

Case Studies33 Reverse Osmosis (RO)


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32

Leaf Growth

Air

Soil

Root System

What is RO? A Plant in Equilibrium

Root Wall(semi-permeable Membrane)

Water

Nutrient


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33

Air

Soil

Root System

Fertilising


AmmoniumSulphate


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34

Air

Soil

Root System

Fertilising


O i


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35

Salty WaterFresh Water

Osmosis

MembraneConcentratedFresh Water

DilutedSalty Water

R O i


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36Reverse Osmosis

Fresh Water ConcentratedSalty Water

AppliedPressure

AppliedPressure


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M ki g S i l W d M b


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38Making a Spiral Wound Membrane

Step 1

SaltyWater

Membrane

Fold

Step 2

FreshWater

Fresh

Water

SaltyWater

SaltyWater

Making a Spiral Wound Membrane


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39

Step 3

Pipe withholes


Step 4

SaltyWater

SaltyWater

FreshWater

FreshWater

SaltyWater

SaltyWater

SaltyWater



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40Making a Spiral Wound Membrane

Step 5

Fresh

Water

SaltyWater

SaltyWater

Salty

Water

SaltyWater

Step 6

SaltyWater

FreshWater

Fibreglass

casing

Membrane Housing


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41

Spiral

Element

Spiral

Element

Feed Concentrate

Permeate

Pressure Vessel

Membrane Housing

RO Unit Configuration - Design


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42RO Unit Configuration - Design

High Quality Permeate

Brine or Concentrate WasteFeed Pump Provides Driving Pressure

Staged Arrays

Concentrate Valve ProvidesBackpressure, sets recovery rate

Membrane Materials


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43Membrane Materials

Cellulose Acetate(CA)

Thin Film Composite(TFC)

Disadvantages

Advantages

High Op. Pressure

pH Sensitive

Low Cost

Lower fouling

No Chlorine tolerance

High Cost

Prone to fouling

Low Op. Pressure

Better salt rejection

High pH range

Membrane Materials


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44Membrane Materials

Cellulose Acetate(CA)

Thin Film Composite(TFC)

Disadvantages

Advantages

High Op. Pressure

pH Sensitive

Low Cost

Lower fouling

No Chlorine tolerance

High Cost

Prone to fouling

Low Op. Pressure

Better salt rejection

High pH range

High Cost

Even Lower

Even

45Gl b l D li ti Pl t G th


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45Global Desalination Plant Growth

0

5000

10000

15000

20000

25000

1965 1970 1975 1980 1985 1990 1995 2000 2005

Installe

dCapacity(ML/day

46RO Improvements


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46RO Improvements

Costs have dropped by 50% in 20 years

Productivity has increased by 100%

Chlorine Resistant, Low Pressure membranes Increased membrane manufacturer competition

Membranes have become a commodity

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47

Case Studies44 Case Studies

48Case Study - Eraring Power Station Reuse


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48Case Study Eraring Power Station Reuse

Beside Lake Macquarie

4 x 660MW coal fired units

Produces 25% of NSWs power Lake water for condenser cooling

Used Hunter Water domestic supply for all other uses

Water Reclamation Plant installed in 1995

First full-scale dual membrane reuse plant in the world


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50y g

0

100

200

300

400

500

600

700

800

900

1994/95 1995/96 1996/97 1997/98 1998/99

NettSavings(000's

)

Production Saving

Water Saving

Power Stations Nett Savings

Data courtesy of Gary Craig - Station Chemist



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51y g

15 year agreement betweenEraring PS & Hunter Water

Station chemists werepassionate about the project

Immediate & significant costbenefits to Hunter Water

Environmental benefits

Power station savings from cheaper water + boiler treatmentchemicals

Why did the project get up?


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54Case Study - Kwinana - Process


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MF Backwash

Prescreening

Raw

Water

RO Units 50 TDS Product

Water Tank

CMF-S

Microfiltration

RO Feed Tank Industrial Customers

Ocean Outfall

Water Quality < 50 mg/L TDS Better than drinking water

55Case Study - Kwinana WRP Customer Drivers


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KWRP is crucial to assist WAsState Government in achieving itsgoal of 20% reused wastewater bythe year 2012

KWRP has doubled Water

Corporations water reusecapacity from 3% to 6%

KWRP will help to reduceWoodman Points effluentdischarge at Cockburn Sound byabout 20%

KWRP will allow up to 16.7ML/d ofpotable water to become availablefor residential use (otherwiseconsumed by local industry)

56Case Study - Illawarra Water Reclamation Plant


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Water Reclamation Plant

57Case Study - Illawarra Water Reclamation Plant


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Part of $197m Illawarra Waste Water Strategy

20 MLD for Bluescope Steel

Dual Membrane(Microfiltration and RO)

50 TDS Product

24 hr/ 7 day supply

Commissioned 2005

58Case Study - Illawarra WRP Customer Drivers


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Replacing current town water usage withhigh purity reuse water

Reduce raw water consumption by greaterthan 60 %

Reduce effluent dischargeto ocean by greater than 40 %

59Case Study - Illawarra WRP - Process


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Bluescope Steel

BNRBiological Nutrient Removal

Tertiary Filtration

Ocean OutfallUV

Wollongong Clarificationand SedimentationPrimary Screening

RO Units

MF Backwash

Product Water

Microfiltration

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NEWater Singaporewww.pub.gov.sg/NEWater


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p g g

61



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p g g

Rainwater

Raw water

Import

NEWater

Reservoir

Waterworks

Population

Industries

Commercial

Water

ReclamationPlants

NEWaterFactories

Desalted WaterSeawater

www.pub.gov.sg/NEWater

IPU

INDIRECT POTABLE USE

62Bedok Demonstration Plant


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Previous studies show MF / RO as preferred process

PUB Commissioned CH2M-Hill to

Design a full scale demonstration plant

for a Design and Health Effect study

63Bedok Demonstration Plant


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Veolia Water won the contract to build the plant

10 MLD

Memcor CMF technology

USFilter RO Studies included a MS2 bateriophage challenge test

64NEWater Safe to drink


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NDNDNDNDViruses

NDNDND3 - 967Coliforms/100ml

Not spec


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Expert Panel Review of 2 year study on

Physical / chemical analysis

Pesticide / herbicide analysis

Radionuclides Synthetic and natural hormones

Microbiological tesing

Study Conclusions

NEWater is considered safe for potable use

Meets WHOs drinking water guidelines

Singapore should adopt the approach of Indirect PotableReuse

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Ulu Pandan 2005

Selestar 2004

Kranji 2003

Changi 2007

Bedok 2002

Tuas Desal 2005

67California ( West Basin & OCWD, Water Factory 21)


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Seawater

Fresh water

20% saline ingress control

80% indirect potable (12-24 months)

Mixing zone sampling

68West Basin, LA, California


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10.5 MLD to aquifer 1997

12.5 MLD to Mobil 1998

22.4 MLD to Arco 1999

15.9 MLD to Chevron 2001

69West Basin, California


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4 Plants

Nett capacity = 64 MLD

Secondary effluent feed

Product to RO for reuse Treated Water quality

SDI


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Talbert Seawater

intrusion barrier

26 injection wells

10 new wells planed

2.5 million population

2% population increase per year25-38 cm rain / year

Started injection in 1976

Blend of

19 MLD RO permeate34 MLD Carbon filtered

32.6 MLD deep well water

< 500 mg/l tds

AQUIFER RECHARGESaline ingress control & indirect potable


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Water Factory 21,Orange County Water District,California.

330 MLD @ 1.19 kWh/m3

(1.8 - 2.6 kWh/m3 for imported water)

Wastewater re-purification for indirect potableLargest ground water replenishment scheme

Plans to expand current 330 MLD project to 494 MLD over 20 years.

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Case Studies55 Frequently Asked MembraneQuestions

73FAQ - What if the membranes fail?


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Membrane degradation is slow

Routine cleaning maintains membrane condition

Ample time to source replacement membranes (good level ofspares in Australia - 000s in US)

Not a big issue, because:

74FAQ - How long do membranes last?


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End of membrane life is project specific (quality or quantity?)

3-7 years , but:

0

200

400

600

800

1000

1200

1400

1600

0 2 4 6 8

Membrane Age (years)

Pressure

0

20

40

60

80

100

120

140

ProductTDS&

Flow

Pressure

Product TDS

Flow

Pressureincreasing

Pressurelimit

TDS Rising

Flow Falling

75FAQ - How long do membranes last?


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End of membrane life is project specific (quality or quantity?)

3-7 years , but:

Type of pretreatment can increase life

Microfilter pretreatment - 5 years or more

Sand filter pretreatment - 3 years

Operating cost balance - Higher Pressure (energy) & frequentcleaning vs capital outlay?

You dont need a full set - keep the best and replace theworst

76FAQ - Are they hard to maintain and operate?


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Daily checks = 1/2hr

Weekly checks = 1hr Daily monitoring can be done remotely

Cleaning a semi-automatic process every 3-6 months

No

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Case Studies66 Design Considerations

78Brine Disposal


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Sewer

Ocean Discharge

Solar Evaporation Dust Suppression

Low grade industrial water

Deep well injection

Thermal Evaporation

Mineral harvesting

Options include:

Easiest & Cheapest

Expensive or Experimental

If you dont know how to dispose of the brine,you dont have a project

79Pretreatment

Poor Pretreatment is the No. 1 killer


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Invest time & $ to define the full range of feed conditions(algae, salts, pH, turbidity etc)

Extremes of feed conditions must be the design basis forpretreatment

Choose pretreatment that gives stable treated water quality

Give greater importance to proven technical solutions over

price

of RO Systems

80

Pretreatment MF/UF in Re-use Applications


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Consistently low SDI (silt density index) < 3

Proven technology

Extends RO membrane warranty from 3 - 5 years Industry Standard for wastewater reuse

81

PretreatmentReduced Biological Fouling


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Particular concern for wastewater re-use

Oxidising disinfectants (Cl2) not compatible with ROmembranes

Chloramine safe forRO membranes.

Formed with NH3 insewage or NH3 added.

Monitored by ORP

ORP vs Concentration

200

300

400

500

600

700

800

0 0.5 1 1.5 2

Concentration (mg/L)

OR

P(mV)

Dichloramine

Free Chlorine

Monochloramine

82

PretreatmentScaling Prevention


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Correct AntiscalantSelection

Correct pH Control(acid dosing)

Will affect maximum recovery

CaCO3/BaSO4/SrSO4/CaF2

Silica Ca3(PO4)2 - Important for Wastewater Reuse

83Design Issue - Recovery


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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10000 20000 30000 40000 50000 60000

Raw Water TDS (mg/L)

T

ypicalRecover

Area of diminishing returns

High cost for increased recovery

More complex equipment

More susceptible to failure

84Design Issue - Recovery


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Aim for:

TDS < 2000mg/L 80-90%

TDS 2000-5000mg/L 75-80% TDS 5000-10000mg/L up to 75%

Seawater (36000mg/L) 40-45%

Sparingly soluble salts may restrict further

DO make brine disposal the key driver for increasing recovery

DONT use the lure of reduced operating cost as the driver forhigh recovery

Recommendations

85Design Issue - Post Treatment


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Low in salts

Low in pH (typically 5 - 6)

Low in Alkalinity

RO Product Water

pH = 7.0 - 8.5 Old, fragile pipe common Aggressive permeate can

lead to pipe failures

Concrete lined pipe also suspect

Drinking Water Standards Distribution Systems

Post Treatment Important

86Design Issue - Post Treatment

P T M h d


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Calcite (CaCO3)

Caustic Soda addition

Degassing (CO2 stripping) Degassing + Caustic Soda

Soda Ash addition

Lime addition

Lime/Caustic addition + CO2

Post Treatment Methods:Small

CapacitySimple

LargeCapacity

Complex

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Case Studies66 Costs

88Main cost impacts


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Feed salinity, variability & fouling potential

Plant Utilisation (Average Flow/Design flow)

Location

Level of standby equipment

Brine disposal

Delivery model

89

Capital Costs - Desalination Design &Construct


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Civil and Building works

Desalination design, supply,

installation and startup Treated Water Storage

Standby pumps

Degassing & Chlorination

Access to site boundary

Raw Water extraction and

delivery to site Operator facilities

Special project requirements

Remote site costs & site

agreements Standby process equipment

Brine/waste disposal

Prices include: Prices exclude:

90Capital Costs - RO Desalination


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0

1,000

2,0003,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

0 2 4 6 8 10

Plant Capacity (ML/day)

Ca

pitalCost(000's)

Good bore (3000mg/L)

Poor bore (3000mg/L)

Secondary Effluent (1000mg/L)

Seawater (beach well)

+/- 20% - Excludes special site conditions and project requirements

91

Operating Costs - Desalination Design &Construct


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Chemicals at commercial quantity

prices Power @ $0.10/kWhr

Operator Labour @ $45/hr

Maintenance

Membrane Replacement using 7%discount rate

Chlorination

Capitalisation

Operations overheads Laboratory analysis

Raw Water delivery costs

Prices include: Prices exclude:

92Operating Costs - RO Desalination


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0.00

0.25

0.50

0.75

1.00

1.25

1.50

0 2 4 6 8 10Plant Capacity (ML/day)

Operatin

gCost($/kLpr

oduced)

Good bore (3000mg/L)

Poor bore (3000mg/L)

Secondary Effluent (1000mg/L)

Seawater (beach well)

+/- 20% - Subject to special site conditions

93Operating cost summary (approximate)

Groundwater pumping costs

A$0 16 - 0 32 / m3


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West Basin A$0.35 / m3

Capex, labour, parts, chemicals, power & waste

Scottsdale A$0.32 / m3

Opex CMF & RO inc. power chemicals & labourExcludes capex inc. civils, laboratory & pilot studies $91.4M

Eraring Power A$0.16 / m3

Opex Analytical costs, spares, chemicals, labour

(no power charge)

Ashkelon A$0.78 / m3 (Sea water RO at 320 MLD)

Energy saving expertise, energy & finance costs

Water Factory 21 Secondary sewage 308 - 494 MLD

50% of the energy needed to import water from N California 66% of the energy needed to treat Colorado river

A$0.16 - 0.32 / m3

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Thankyou

membranes for water recylcing - t walker

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