Water Reuse for Augmentation of Water Supply

Water Reuse for Augmentation of Water Supply

Water Reuse for Augmentation of Water Supply

Joseph G. JacangeloJoseph G. Jacangelo1,21,2

Tamar S. LevenbergTamar S. Levenberg11

James DeCarolisJames DeCarolis11

11MWHMWH22The Johns Hopkins UniversityThe Johns Hopkins University

Your Drinking Water: Challenges and Solutions for the 21Your Drinking Water: Challenges and Solutions for the 21stst CenturyCentury

April 20-21, 2009April 20-21, 2009

Joseph G. JacangeloJoseph G. Jacangelo1,21,2

Tamar S. LevenbergTamar S. Levenberg11

James DeCarolisJames DeCarolis11

11MWHMWH22The Johns Hopkins UniversityThe Johns Hopkins University

Your Drinking Water: Challenges and Solutions for the 21Your Drinking Water: Challenges and Solutions for the 21stst CenturyCentury

April 20-21, 2009April 20-21, 2009

Presentation OverviewPresentation Overview• Overview and drivers for water reuseOverview and drivers for water reuse

• Water quality and regulatory considerations for reuseWater quality and regulatory considerations for reuse

• Contaminant exposure routesContaminant exposure routes

• Advanced treatment for selected constituents of Advanced treatment for selected constituents of concernconcern

• Summary: Future trends in water reuseSummary: Future trends in water reuse

What is Water Reuse?What is Water Reuse?

The reclamation and treatment The reclamation and treatment of impaired waters for the of impaired waters for the

purpose of beneficial reuse. purpose of beneficial reuse.

WateReuse Association, 2003WateReuse Association, 2003


The reclamation and treatment The reclamation and treatment of of impaired waters impaired waters for the for the



Impaired WatersImpaired Waters

• Municipal and industrial wastewater Municipal and industrial wastewater effluenteffluent

• Brackish waterBrackish water• Poor quality groundwaterPoor quality groundwater• Agriculture return flowsAgriculture return flows• StormwaterStormwater



purpose of purpose of beneficial reusebeneficial reuse. .


• Non-Potable Reuse – Examples: Non-Potable Reuse – Examples: irrigation and industrial reuseirrigation and industrial reuse

Types of Water ReuseTypes of Water ReuseTypes of Water ReuseTypes of Water Reuse

• Potable Reuse - includes drinking Potable Reuse - includes drinking waterwater

Direct potable reuseDirect potable reuse

Indirect potable reuseIndirect potable reuse

Uses of Reclaimed Water Uses of Reclaimed Water

• Agricultural Agricultural irrigationirrigation

• Landscape Landscape irrigationirrigation

• Nonpotable urban Nonpotable urban usesuses

• Industrial usesIndustrial uses• ImpoundmentsImpoundments

• Environmental Environmental usesuses

• Groundwater Groundwater rechargerecharge

• Indirect potable Indirect potable reusereuse

• Planned – Engineered systems to Planned – Engineered systems to provide augmentation of water supplyprovide augmentation of water supply

Types of Indirect Potable ReuseTypes of Indirect Potable ReuseTypes of Indirect Potable ReuseTypes of Indirect Potable Reuse

• Unplanned – Withdrawal of water Unplanned – Withdrawal of water from water bodies that have received from water bodies that have received wastewater or other types of wastewater or other types of dischargesdischarges

Mississippi, Ohio, S. Platte riversMississippi, Ohio, S. Platte rivers

The “magic” of the river bedThe “magic” of the river bed

Global Drivers of ReuseGlobal Drivers of Reuse• Rising Water DemandsRising Water Demands

– Demographic, economic growthDemographic, economic growth– Urban growthUrban growth

• Finite Water ResourcesFinite Water Resources– Nearby sources: Rare & vulnerableNearby sources: Rare & vulnerable– Remote sources : Costly to developRemote sources : Costly to develop

• Regulatory & Political Pressure Regulatory & Political Pressure – Effluent disposal (zero discharge)Effluent disposal (zero discharge)– Environmental issues associated with impoundments (no Environmental issues associated with impoundments (no

dams)dams)

Total Water PortfolioTotal Water Portfolio

• FreshwaterFreshwater• Brackish and SeawaterBrackish and Seawater• ConservationConservation• GroundwaterGroundwater• Reclaimed waterReclaimed water

Current Status of Water Reuse in Current Status of Water Reuse in the United Statesthe United States

• Approximately 1,500 water reuse facilities in Approximately 1,500 water reuse facilities in U.S.U.S.

• Only 5-7% of wastewater is currently reused Only 5-7% of wastewater is currently reused

• ““I believe the Last River for us to tap is I believe the Last River for us to tap is Wastewater.Wastewater.” ” - John Keys, Commissioner USBR- John Keys, Commissioner USBR

Water Reuse Breakdown

California

FloridaSource: US EPA. Guidelines for water reuse

Largest Water Reuse Programs in the United States

• OCWD• Central/West Basin• MWD• San Jose• LACSD• San Diego County• Irvine Ranch• Dublin San Ramon• EBMUD• Orlando• Scottsdale

• Phoenix• San Antonio• El Paso• Tarrant Regional• St. Petersburg• Pinellas County• King County (WA)• Austin• Santa Rosa• UOSA (VA)• SNWA/LVVWD

Groundwater Recharge - SpreadingGroundwater Recharge - Spreading

Groundwater Recharge - InjectionGroundwater Recharge - Injection

Upper Occoquan Sewage Authority, Virginia, Upper Occoquan Sewage Authority, Virginia, Water Reclamation Plant – 20 years of operationWater Reclamation Plant – 20 years of operation

More Stringent Regulations

Less Stringent Regulations

Regulations and Guidelines Vary Regulations and Guidelines Vary Depending on Type of ReuseDepending on Type of Reuse

• Indirect Potable ReuseIndirect Potable Reuse• Agricultural Reuse on Food CropsAgricultural Reuse on Food Crops• Unrestricted Recreational ReuseUnrestricted Recreational Reuse• Unrestricted Urban Irrigation ReuseUnrestricted Urban Irrigation Reuse• Restricted Urban Irrigation ReuseRestricted Urban Irrigation Reuse• Restricted Recreational ReuseRestricted Recreational Reuse• Industrial ReuseIndustrial Reuse• Environmental ReuseEnvironmental Reuse• Agricultural Reuse on Non-food CropsAgricultural Reuse on Non-food Crops

Reuse Applications and Number of States with Guidelines

Type of Reuse Number of States

Unrestricted Urban 28

Restricted Urban 34

Agricultural (Food Crops) 21

Agricultural (Non-food Crops) 40

Unrestricted Recreational 7

Restricted Recreational 9

Environmental (Wetlands) 3

Industrial 9

Groundwater Recharge (Nonpotable Aquifer)

5

Indirect Potable Reuse 5

2004 Guidelines for Water Reuse, EPA/625/R-04/108

Title 22 Requirements for Non – Title 22 Requirements for Non – Potable ReusePotable Reuse

• Secondary treatmentSecondary treatment

• Filtration turbidity of 2 NTUFiltration turbidity of 2 NTU

• 2.2 total coliforms/100 mL2.2 total coliforms/100 mL

• CT = 450 mg/L-minCT = 450 mg/L-min

Requirements for Indirect Potable Requirements for Indirect Potable ReuseReuse

• Secondary and advanced treatmentSecondary and advanced treatment

• Drinking water regulationsDrinking water regulations

• Monitoring of other constituents of concern Monitoring of other constituents of concern (TOC, nitrogen, phosphorus, EDCs/PPCPs(TOC, nitrogen, phosphorus, EDCs/PPCPs

• Environmental BufferEnvironmental Buffer

Water QualityWater Quality

Constituents of Constituents of Concern in Water Concern in Water

ReuseReuse

MicrobesMicrobes OrganicsOrganics MetalsMetals Nutrients Nutrients SaltSalt

DomesticDomesticUseUse

CommercialCommercialUseUse

IndustrialIndustrialUseUse

To Wastewater TreatmentTo Wastewater Treatment

WaterWaterSupplySupply

Water Quality Issues That Effect End UseWater Quality Issues That Effect End Use

• Cooling TowersCooling Towers– Nutrients, TDS, suspended solids, Nutrients, TDS, suspended solids,

chlorides, odor, hardness, chlorides, odor, hardness, bacteriologicalbacteriological

• Textile MillTextile Mill– Color, inorganics, chlorine, odorColor, inorganics, chlorine, odor

• Cement ManufacturersCement Manufacturers– Suspended solids, inorganicsSuspended solids, inorganics

• Wetland EnhancementsWetland Enhancements– NutrientsNutrients


• AgriculturalAgricultural– TDS, boron, chloride, chlorine, suspended TDS, boron, chloride, chlorine, suspended

solidssolids

• Toilets and Urinal FlushingToilets and Urinal Flushing– Suspended solids, color, odorSuspended solids, color, odor

• Wetland EnhancementsWetland Enhancements– NutrientsNutrients

• Indirect Potable ReuseIndirect Potable Reuse– DWR, EDCs/PPCPs, OthersDWR, EDCs/PPCPs, Others

Exposure to Exposure to Contaminants of Contaminants of

ConcernConcern

Selected Routes of Exposure to Reclaimed WaterSelected Routes of Exposure to Reclaimed Water

• Direct exposureDirect exposure– Contact from surfaces exposed to reclaimed waterContact from surfaces exposed to reclaimed water

– Accidental ingestionAccidental ingestion

– Consumption of fruits and vegetables irrigated with reclaimed waterConsumption of fruits and vegetables irrigated with reclaimed water

– Contact with aerosols from spray irrigation or cooling towersContact with aerosols from spray irrigation or cooling towers

– Ingestion through indirect potable reuseIngestion through indirect potable reuse

• Indirect exposureIndirect exposure– Impact environmental matrices and affect the transport of pollutants Impact environmental matrices and affect the transport of pollutants

(irrigation of soils – overspray)(irrigation of soils – overspray)

BacteriaBacteria VirusesViruses ProtozoaProtozoa

Campylobacter Hepatitis A Giardia

Escherichia coli Reovirus Cryptosporidum

Salmonella Calicivirus Entameoba

Yersinia Enterovirus Microsporidium

Vibrio Coxsackievirus

Legionella AdenovirusAeromonas EchovirusMycobacterium PoliovirusShigellaPseudomonas

Important Waterborne PathogensImportant Waterborne Pathogens

Concentration Ranges of Selected Concentration Ranges of Selected Microorganisms Found in Raw WastewaterMicroorganisms Found in Raw Wastewater

Number perMicroorganism 100 mL

Fecal coliforms 105 - 107

Fecal streptococci 104 - 106

Shigella 100 - 103

Samonella 102 - 104

Pseudomonas aeruginosa 103 - 104

Giardia lamblia cysts 101 - 104

Cryptosporidium oocysts 102 - 105

Entamoeba histolytica cysts 102 - 105

Enteric viruses 103 - 104

Helminth ova 100 - 103

Adapted from NRC, 1998Adapted from NRC, 1998

Multiple Barrier Approach to Risk ManagementMultiple Barrier Approach to Risk Management

• Source controlSource control• Appropriate treatment (multiple barriers)Appropriate treatment (multiple barriers)• Storage, transmission and distribution protectionStorage, transmission and distribution protection

– Cross connection control / backflow prevention, pipe line separationCross connection control / backflow prevention, pipe line separation

• Protection of usage areasProtection of usage areas– Warning signs, buffer zones, cross connection control, end-user Warning signs, buffer zones, cross connection control, end-user

agreements, user notificationsagreements, user notifications

MONITORING TO ASSURE BARRIERS ARE WORKINGMONITORING TO ASSURE BARRIERS ARE WORKING

Treatment for Treatment for Contaminant RemovalContaminant Removal

DisinfectionDisinfectionPre-treatmentPre-treatmentPrimaryPrimary Activated sludgeActivated sludge ClarifierClarifier

ChemicalsChemicals SedimentationSedimentation

Sand filterSand filter

MF/UFMF/UF DisinfectionDisinfection

Reverse OsmosisReverse Osmosis Disinfection/OxidationDisinfection/Oxidation

Reverse OsmosisReverse Osmosis Disinfection/ Disinfection/ OxidationOxidation

Water Reuse Treatment TrainsWater Reuse Treatment Trains

ScreeningScreening MBRMBR DisinfectionDisinfection

Raw SewageRaw Sewage

Membrane Modules

Spiral Wound Membrane

UV Systems

Calgon UV System

Treatment for InorganicsTreatment for Inorganics(Membrane Bioreactor and Reverse Osmosis)(Membrane Bioreactor and Reverse Osmosis)

Sunrise Treatment StreamsSunrise Treatment Streams

MBR

RO

CompoundCompound UnitsUnits RangeRange AvgAvg

Bio. Oxygen Demand (CBODBio. Oxygen Demand (CBOD55)) mg/Lmg/L 90-48090-480 244244

Total Suspended Solids (TSS) Total Suspended Solids (TSS) mg/Lmg/L 26-24026-240 130130

Total Nitrogen (TN)Total Nitrogen (TN) mg/Lmg/L 7 -787 -78 4040

Total Phosphorus (TP)Total Phosphorus (TP) mg/Lmg/L 8 8 –– 33 33 2222

Total PhosphatesTotal Phosphates mg/Lmg/L 1 - 111 - 11 88

Influent Wastewater Influent Wastewater CharacterizationCharacterization

Removal of Suspended SolidsRemoval of Suspended Solids

1.0

10.0

100.0

1000.0

5-Apr 20-Apr 5-May 20-May 4-Jun 19-Jun 4-Jul 19-Jul 3-Aug 18-Aug 2-Sep 17-Sep 2-Oct

mg

/L

Influent

MBR Permeate

WQ Goal

Removal of Total NitrogenRemoval of Total Nitrogen

0.1

1.0

10.0

100.0

5-Apr 20-Apr 5-May 20-May 4-Jun 19-Jun 4-Jul 19-Jul 3-Aug 18-Aug 2-Sep 17-Sep 2-Oct

mg

/L

InfluentMBR PermeateRO PermeateWQ Goal

Removal of PhosphatesRemoval of Phosphates

0.00

0.01

0.10

1.00

10.00

5-Apr 17-Apr 29-Apr 11-May 23-May 4-Jun 16-Jun 28-Jun 10-Jul 22-Jul 3-Aug 15-Aug 27-Aug 8-Sep 20-Sep 2-Oct 14-Oct

mg

/L

InfluentMBR PermeateRO PermeateWQ Goal

ReverseOsmosis Treatment

Alumin

MBR

Alumin

MBR

Treatment for Treatment for MicroorganismsMicroorganisms

1E+00

1E+01

1E+02

1E+03

1E+04

1E+05

1E+06

1E+07

1E+08

1E+09

0 250 500 750 1000 1250 1500 1750 2000 2250 2500

Time of Operation. hours

Co

nce

ntr

atio

n,

MP

N/1

00m

L

Primary Effluent Fecal Coliforms

MBR Permeate Fecal Coliforms

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

1.00E+09

0 250 500 750 1000 1250 1500 1750 2000 2250 2500

Time of Operation, hours

Co

nce

ntr

atio

n,

PF

U/1

00 m

L

Primary Effluent Total Coliphage

MBR Permeate Total Coliphage

Fecal Coliform Bacteria and Coliphage in MBR Fecal Coliform Bacteria and Coliphage in MBR EffluentEffluent

Free chlorineFree chlorine ExcellentExcellent ExcellentExcellent Fair/PoorFair/Poor GoodGood

ChloraminesChloramines FairFair PoorPoor Very PoorVery Poor PoorPoor

Chlorine dioxideChlorine dioxide Good/ExcellentGood/Excellent Good/ExcellentGood/Excellent FairFair GoodGoodOzoneOzone ExcellentExcellent ExcellentExcellent GoodGood Good/ExcellentGood/ExcellentUltraviolet irradiationUltraviolet irradiation ExcellentExcellent Fair/GoodFair/Good ExcellentExcellent Good/ExcellentGood/Excellent

Filtration ProcessesFiltration Processes

Granular Media FiltrationGranular Media Filtration GoodGood FairFair GoodGood GoodGood

Membrane BioreactorMembrane Bioreactor ExcellentExcellent Good/ExcellentGood/Excellent ExcellentExcellent ExcellentExcellent

DisinfectantsDisinfectants BacteriaBacteria VirusesViruses ProtozoaProtozoa Overall RatingOverall Rating

Comparison of Microbial Inactivation or Removal Comparison of Microbial Inactivation or Removal Efficacy by Selected Disinfectants and Filtration Efficacy by Selected Disinfectants and Filtration

ProcessesProcesses

Comparison of Microbial Inactivation or Removal Comparison of Microbial Inactivation or Removal Efficacy by Selected Disinfectants and Filtration Efficacy by Selected Disinfectants and Filtration

ProcessesProcesses

Adapted from Trussell, 1993Adapted from Trussell, 1993

Treatment for Endocrine Treatment for Endocrine Disrupting Compounds (EDCs) Disrupting Compounds (EDCs)

and Pharmaceuticals and Personal and Pharmaceuticals and Personal Care Products (PPCPs)Care Products (PPCPs)

(Reverse Osmosis and UV Advanced Oxidation)(Reverse Osmosis and UV Advanced Oxidation)

Endocrine Disrupting Compounds

• Endocrine Disrupting Compounds are contaminants of emerging concern

• Removal by conventional wastewater processes are often at low levels

• Advanced treatment often required

Examples of EDC/PPCPs Examples of EDC/PPCPs

SteroidsSteroids

ReclaimedReclaimedWaterWater

MarketMarket(27,000 m(27,000 m33/day)/day)

Municipal Municipal WastewaterWastewater

(114,000 m(114,000 m33/day)/day)

WaterReclamation

Plant

AdvancedWater

Treatment (AWT)

WaterFiltration

Plant

ReservoirReservoir

ToToPotable SupplyPotable Supply

FirstFirstAqueductAqueduct

Advanced Water Treatment (AWT) Advanced Water Treatment (AWT)

(61,000 m(61,000 m33/day)/day)

(361,000 m(361,000 m33/day)/day)

OthersOthers

~ 28 month~ 28 month detentiondetention timetime


Reverse Osmosis

(RO)

ConcentrateConcentrateBackwashBackwash

Tertiary Wastewater

Ultraviolet (UV)

Ultrafiltration(UF)

Reuse

H2O2

Advanced Oxidation

Step 1: UltrafiltrationStep 1: Ultrafiltration Step 2: Reverse osmosisStep 2: Reverse osmosis

Step 3: Advanced oxidationStep 3: Advanced oxidation


Units AWT Product Water MCL or Notification Level

Nitrate mg/L-N 1.6 10

TTHMs ug/L 3 80

1,4 Dioxane ug/L 2.8 3

NDMA ng/L 2.3 10

Removal of Selected Compounds by AWTRemoval of Selected Compounds by AWT

EDC/PPCP AWT Removal ResultsEDC/PPCP AWT Removal Results

1 n=1

RO In (n=2)

RO Out (n=2)

UV + Peroxide (n=2)

Hydrocodone ng/L 1 80 <1.0 <1.0Trimethoprim ng/L 1 384 2.95 <1.0

Acetaminophen ng/L 10 <10 <10 <10Caffeine ng/L 10 <10 <10 <10

Erythromycin-H2O ng/L 1 298 <1.0 <1.0Sulfamethoxazole ng/L 1 892 2.9 <1.0

Fluoxetine ng/L 1 33 <1.0 <1.0Pentoxifylline ng/L 1 12 <1.0 <1.0Meprobamate ng/L 1 292 1.5 <1.0

Dilantin ng/L 1 144 <1.0 <1.0TCEP ng/L 10 272 <10 <10

Carbamazepine ng/L 1 279 2.4 <1.0DEET ng/L 5 293 <5.0 <5.0

Atrazine ng/L 1 1 <1.0 <1.0Diazepam ng/L 1 1 <1.0 <1.0

Oxybenzone ng/L 5 21 <5.0 <5.0Estriol ng/L 5 14 <5.0 <5.0

Ethynylestradiol ng/L 1 <1.0 <1.0 <1.0Estrone ng/L 1 101 <1.0 <1.0Estradiol ng/L 1 18 <1.0 <1.0

Testosterone ng/L 1 <1.0 <1.0 <1.0Progesterone ng/L 1 <1.0 <1.0 <1.0

Androstenedione ng/L 1 5 <1.0 <1.0Iopromide ng/L 1 632 1.4 <1.0Naproxen ng/L 1 255 1.2 <1.0Ibuprofen ng/L 1 79 <1.0 <1.0Diclofenac ng/L 1 89 <1.0 <1.0Triclosan ng/L 1 1 324 1 3.4 1 <1.0

Gemfibrozil ng/L 1 1022 1.3 <1.0

Parameter UnitsMethod

Detection Limit

AWT Process Location

Efficacy of Various Treatment TechnologiesEfficacy of Various Treatment Technologies

Sour

ce:

Mod

ified

from

Sny

der e

t al.,

200

3, E

nv. E

ng. S

ci., 2

0(5)

: 456

.

Class of Compounds R

ever

se O

smo

sis

Bac

teri

ost

atic

A

ctiv

ated

Car

bo

n

Act

ivat

ed C

arb

on

Nan

ofi

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tio

n

Bio

deg

rad

atio

n

Ad

van

ced

O

xid

atio

n

Ph

oto

deg

rad

atio

n

Act

ivat

ed S

lud

ge

UV

Fre

e C

hlo

rin

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Ch

lori

ne

Dio

xid

e

So

ften

ing

Co

agu

lati

on

/ F

locc

ula

tio

n

PesticidesIndustrial chemsSteroidsMetalsInorganicsOrganometallicsAntibioticsAnti-depressantsAnti-inflamatoryLipid regulatorsX-ray contrast Psyciatric controlSynthetic musksSunscreensAnti-microbialsDetergents

Legend:Removal Rates >90% 70-90% 40-70% <20% Varies

Summary: Non-Technical Barriers to Summary: Non-Technical Barriers to Indirect Potable Water ReuseIndirect Potable Water Reuse

• Public/user perception and cultural Public/user perception and cultural issues – “Toilet to Tap Syndrome”issues – “Toilet to Tap Syndrome”

• Better documentation of economics Better documentation of economics of water reuseof water reuse

• Support by local authoritiesSupport by local authorities

• Project fundingProject funding

Is Direct Water Reuse in our Is Direct Water Reuse in our Future? Future?

• Question is being asked more and more by experienced users

• Technical issue – Risk of failure– No time to recover – public health implications– Few studies focusing on failure analysis

• Perception Issues

Summary: Trends in Water ReuseSummary: Trends in Water Reuse

• Dual systemsDual systems

• Acceptability of indirect potable reuseAcceptability of indirect potable reuse

• UV for disinfection and advanced UV for disinfection and advanced oxidationoxidation

• Membrane processesMembrane processes

• Distributed water reuse facilities Distributed water reuse facilities

Summary: Trends in Water ReuseSummary: Trends in Water Reuse

• Regulation development, including Regulation development, including current regulationscurrent regulations

• Integrated resource planningIntegrated resource planning

• User perception studiesUser perception studies

• Water reuse as a center for sustainable Water reuse as a center for sustainable developmentdevelopment

EndEnd

Legislation

Legislation

• All waters regulated by the Safe Drinking Water Act

• Pathogenic microorganisms, regulated chemicals, nitrogen compounds and unregulated chemicals are of concern.

Texas Direct Reuse Regulations

• Effective 2-12-97• Reuse of untreated effluent is prohibited (TNRCC §210.22(a))• Food crops to be consumed raw cannot be spray irrigated

(§210.22(b))• Reclaimed water cannot be utilized in a way that degrades

groundwater quality (§210.22(d))• Storage ponds for reclaimed water cannot be located within the

floodway (§210.23(a))• All initial holding ponds must be lined properly in accordance with

§210.23(c,d), which are designed to prevent leaking into groundwater

• Irrigators must apply reclaimed water efficiently and avoid excess application that might lead to runoff or percolation (§210.24(a))

• Reclaimed water piping must be separated from potable water piping by a horizontal distance of 9 feet (§210.25(c))

Microorganism Control Requirements

• Secondary treatment • Filtration

– 2 NTU

• Disinfection – 2.2 total coliform MPN/100mL

• Residence time in the environment– Spreading – 6 months– Direct injection – 12 months

Regulated Chemical Control

• Drinking Water Standards

• Developed as needed (occurrence) and only when health effects, detection method, and treatment are known

• Set of DWS not sufficient for impaired sources or indirect potable reuse

Unregulated Chemical Control

• Monitor for Priority Pollutants and Chemicals with Action Levels,

• Plus, this is a dynamic situation– Industrial practices change– Pharmaceutical prescription preferences change– Public perceptions change

• Chemicals may also be selected to be monitored for because their presence may indicate that other chemicals of similar characteristics or origin are present. These other chemicals may have a specific human health effect.

Nitrogen Compound Control

• A total nitrogen standard of 5 mg/L is set because all forms of nitrogen could convert to nitrate or nitrite in the groundwater

Direct Reuse Issues

• Equity– Essentially, water reuse allows one user to delay the

need to pursue additional resources while forcing another (or many others) to do so sooner rather than later

– Moral equity is the basis for many legal statutes

• Legal– Direct reuse has the potential to undermine the prior

appropriation system by depriving some users of their allotted water

– One of these users is the environment

Direct Reuse Issues, cont.

• Financial/Institutional– Reuse projects require a substantial amount of capital,

and must be a cost-effective option– City of Phoenix and Palo Verde Nuclear Power Plant

• PUBLIC ACCEPTANCE/HEALTH– Reusing treated wastewater has a negative perception– Although less scrutiny towards non-potable reuse, there are still

areas where it is frowned upon• Agricultural irrigation is still handled cautiously

Direct Water Reuse Issues, cont.

– Potable reuse is much higher risk, therefore water utilities, regulatory agencies, the scientific community and the public have stigmatized it

• Prohibited in most states• Propaganda such as “toilet-to-tap” and “sewage

beverage”• Public education and confidence in water utility

competence are paramount

Indirect Reuse Issues

• Economic feasibility– Relates to equity– Reused water might not be put to the most economically

efficient use– Should profitability be a criteria for indirect reuse permits?

• Marketing– Can a large water user, such as a municipality or industry,

sell its treated effluent using the bed and banks of a river?

Potable Reuse

• Direct reuse– The form of reuse characterized by transport via

pipes or canals

• Indirect reuse– The use of natural water bodies (usually

rivers/streams, but also lakes/reservoirs and aquifers) to transport and/or purify reclaimed water, also called bed and banks and ASR.

Increased Cost

• Additional Treatment• Conveyance, Distribution and Storage• Additional Monitoring• Decrease in water sales revenue• Can be cost effective if

– Water supply is of poor quality– Water supply does not meet demand– Advanced wastewater treatment already required


• AgricultureAgriculture– TDS, boron, chloride, chlorine, suspended solidsTDS, boron, chloride, chlorine, suspended solids

• Landscaping / Single Family HomesLandscaping / Single Family Homes– TDS, boron, chloride, chlorine, SS, odorsTDS, boron, chloride, chlorine, SS, odors

• Toilets and Urinal FlushingToilets and Urinal Flushing– Suspended solids, color, odorSuspended solids, color, odor

• Water FeaturesWater Features– Nutrients, colorNutrients, color

Ulu Pandan NE, Singapore Water Ulu Pandan NE, Singapore Water PlantPlant

Process SchematicProcess Schematic

Micro-strainer

Feedwater Equalization

(Balance) Tank

MF/UF Membrane Filtration

Ultraviolet (UV) Light

Disinfection

RO Membranes

NEWater Storage Tank

To UsersNEWater

RO Permeate

MF/UF Filtrate

Secondary Treated Effluent

Filtrate Balance & Backwash Water

Tank

Murrumba Downs AWTP Murrumba Downs AWTP Process Process SchematicSchematic

WWTP EFFLUENT

PRODUCT WATER TANK

AWTP BALANCE

TANK

MF

FILTRATE TANK

REVERSE OSMOSISMICROFILTRATION

Ammonium Sulphate &

Sodium Hypochlorite

Sodium Hypochlorite

AntiscalantSulphuric

Acid

Lime Water & Carbon Dioxide

Product Water to Amcor

RO Concentrate

to WWTP Outfall

GI AWTP Process FlowGI AWTP Process Flow

CONCENTRATE

FROM GIBSON ISLAND WWTP

ACTIFLORAW WATER

BALANCE

RO

UV

MF

NEUTRALISED CIP TO WWTP

PRODUCT WATER

FROM LUGGAGE POINT WWTP

==

MF FEED

CHLORAMINE

==

RO FEED

COAGULANT & pH ADJUSTMENT

TO RIVER OUTFALL

==

TREATED WATER

ANTI-SCALANT & pH ADJUSTMENT H2O2 LIME & HYPO CO2

THICKENER

==

SOLIDS BALANCE

==

SLUDGE HOLDING

CENTRIFUGE

CENTRATE TO WWTP

SUPERNATANT TO RAW WATER

Water Reuse for Augmentation of Water Supply

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