supplemental lecture 1 water constituents

7/29/2019 Supplemental Lecture 1 Water Constituents

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Water Constituents and

Water Quality Issues

Department of Civil and Environmental EngineeringEGGN/ESGN 454 - Water Supply Engineering

WaterFactsofLife

ThereisthesameamountofwateronEarthastherewaswhentheEarthwasformed.Thewaterfromyourfaucetcouldcontain

moleculesthatdinosaursdrank Humanscanliveaboutamonthwithoutfood,butonlyabouta

weekwithoutwater

Nearly97%oftheworldswaterissaltyorotherwiseundrinkableand2%islockedinicecapsandglaciers

Thatleavesjust1%forallofhumanitysneeds: residenFal industrial/agricultural community

TheaveragetotalresidenFalwateruseintheU.Sisabout50gallons/day/person

TheaveragecostforwatersuppliedtoahomeintheU.S.isabout$2per1,000gallons,whichisabout5gallonsforapenny

SurfaceWater Groundwater

Conven7onalSurfaceWaterTreatmentTrain

Public Water System Inventory data (2005)

http://www.epa.gov/safewater/data/getdata.html

Type Very small100,000

Total

CWS # of systems 29,666 14,389 4,748 3,648 386 52,837

Pop. served 4,925,748 20,851,292 27,514,714 102,747,558 126,304,807 282,344,119

% of systems 56% 27% 9% 7% 1% 100%

% of population 2% 7% 10% 36% 45% 100%

NTNCWS # of systems 16,348 2,707 102 17 19,174

Pop. served 2,282,628 2,710,912 557,742 504,915 6,056,197

% of systems 85% 14% 1% 0% 0% 100%

% of population 38% 45% 9% 0% 0% 100%

TNCWS # of systems 83,351 2,721 111 23 4 86 ,210

Pop. served 7,298,704 2,667,051 598,506 604,213 2,994,000 14,162,474

% of systems 97% 3% 0.13% 0.03% 0% 100%

% of population 52% 19% 4% 4% 21% 100%

Total # of Sys. 142,386 14,196 156,582


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Type Ground Water Surface Water Totals

CWS # of systems 40,018 11,737 51,755

Population served 89,539,197 191,130,147 280,669,344

% of systems 77% 23% 100%

% of population 32% 68% 100%

NTNCWS # of systems 18,438 607 19,045

Population served 5,410,376 611,002 6,021,378

% of systems 97% 3% 100%


TNCWS # of systems 83,930 1,852 85,782

Population served 11,305,555 801,399 12,106,954

% of systems 98% 2% 100%


Total # of Systems 142,386 14,196 156,582

PublicWaterSystemInventorydata(2005)

WaterCharacteris7cs

PhysicalMeasures:StreamFlow

Waterflowimpactswaterquality,livingorganisms,andhabitatsinthestream

Large,swiQlyflowingriverscanreceivepolluFondischargesandbeminimallyaffected

Smallstreamshavelesscapacitytodiluteanddegradewastes

Oxygenlevelincreaseswithflow Sedimenttransportaffectedbyflow

PhysicalMeasures:Temperature

Generallyincreaseswithstreamsize&openwatersurfacearea

Ratesofbiologicalandchemicalprocesses Oxygencontentofthewater RateofphotosynthesisbyaquaFcplants MetabolicratesofaquaFcorganisms SensiFvityoforganismstotoxicwastes,

parasites,anddiseases

Temperatureinfluencedby: weather shading/streambankvegetaFon impoundments discharges/urbanstormwater groundwaterinflows

PhysicalMeasures:Turbidity/SuspendedSediment

Ameasureofwaterclarity(NephelometricTurbidityUnitsNTU)

Sizerangeof0.004mm(clay)to1.0mm(sand) SuspendedmaterialsincludesoilparFcles(clay,silt,andsand),

algae,plankton,microorganisms,andmore Sourcesofturbidityinclude:soilerosion,wastedischarge,

urbanrunoff,erodingstreambanks,largenumbersofbo_om

feeders(suchascarp),excessivealgalgrowth

Canaffectthecolorofthewater Higherturbidityincreaseswatertemperatures;suspended

parFclesabsorbmoreheatreducesDOconcentraFon

HigherturbidityreducestheamountoflightpenetraFngthewaterreducesphotosynthesisandtheproducFonofoxygen

AffectsthehealthofaquaFclife

Cons7tuentsinNaturalWater

Important Properties:

ChargeHydrophobicity

Solubility, volatility

Organics

Metals & Ligands

Dissolved Species


Size, shape,density

surface charge

Organic: bacteria,

protozoa, virus

Inorganic: clay

(Turbidity)

Particles


SolubilityVolability

Interface (G/L)

Ammonia, chlorine,

ozone, et al.

Oxygen

Carbon dioxide

Gases

Constituents


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CommonCons7tuents

Cations Anions

Calcium (Ca2+) Bicarbonate (HCO3-) and Carbonate (CO32-)

Magnesium (Mg2+) Chloride (Cl-)

Sodium (Na+) Sulfate (SO42-)

Potassium (K+) Nitrate (NO3-)

Iron (Fe2+) Fluoride (F)

Manganese (Mn2+) Phosphate (PO43-)

AsO3-3, AsO4

-3

InorganicCons7tuents(Primarilyderivedfromrocksandsoils)

PopulationServed

Surface Water Ground Water

Systems with Fluoride (mg/L) Systems with Fluoride (mg/L)

< 1.0 1.0 - 2.0 2.0 - 4.0 > 4.0 < 1.0 1.0 - 2.0 2.0 - 4.0 > 4.0

< 500 3,670 117 5 3 31,931 2,281 833 220

500-2,500 2,980 265 6 1 8,964 341 165 40

2,500-10,000 1,967 174 3 2 2,828 219 44 14

> 10,000 1,615 148 2 0 1,187 48 6 2

FluorideinPublicWaterSupply

ManycommuniFesaddfluoridetotheirdrinkingwatertopromotedentalhealth

HigherconcentraFonsingroundwaterthansurfacewaters

Cations Anions

Calcium (Ca2+) Bicarbonate (HCO3-) and Carbonate (CO3

2-)

Magnesium (Mg2+) Chloride (Cl-)

Sodium (Na+) Sulfate (SO42-)

Potassium (K+) Nitrate (NO3-)

Iron (Fe2+) Fluoride (F)

Manganese (Mn2+) Phosphate (PO43-)

AsO3-3, AsO4

-3

InorganicCons7tuents

Arsenic(As)hasbeenassociatedwithcancerh_p://www.epa.gov/safewater/arsenic/index.html

Equal-areamap:ArsenicconcentraFonsfoundinatleast25%ofground-

watersampleswithinamoving50kmradius

ArsenicinGroundwaterSystems

Datamap:31,350ground-waterarsenicsamplescollectedin1973-2001

ArsenicinGroundwaterSystems

Higheroccurrenceingroundwaterthansurfacewaters


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ExpressionsofConcentra7ons

EW=

MW

Z

WeightConcentraFon:gr/L,mg/L(ppm),g/L(ppb),ng/L(ppt) Molarity(M):mol/L,mmol/L(xmoleofAdissolvedinwaterto

make1literofsoluFon) Molality(m):xmoleofAdissolvedin1literofwatertomake

slightlymorethan1litersoluFon

Normality(N):eq/L,meq/L, equivalentweight:

Zis: Theabsolutevalueoftheioncharge ThenumberofH+orOHionsaspeciescan

reactwithoryieldinandacid-basereacFon

Examples

Whatistheequivalentweightofcalcium?

Whatistheequivalentweightofcalciumcarbonate(CaCO3)?

WhatconcentraFonis40mg/lCa2+whenexpressedasCaCO3?

mg/L mmol/L meq/L mg/L mmol/L meq/L

Ca2+ 180 HCO3 300

Mg2+ 65 CO32 40

Na+ 60 SO42 60

K+ 20 Cl 348

e(II) 0.5 NO3 35

Cd(II) 0.5

SUM SUM

Calculatemolarityandnormality

Classwork#1


Ca2+ 180 4.49 HCO3 300 4.92

Mg2+ 65 CO32 40

Na+ 60 SO42 60

K+ 20 Cl 348

e(II) 0.5 NO3 35

Cd(II) 0.5

SUM SUM

Classwork#1


Ca2+ 180 4.49 HCO3 300 4.92

Mg2+ 65 2.67 CO32 40 0.66

Na+

60 2.61 SO42

60 0.625K+ 20 0.51 Cl 348 9.8

e(II) 0.5 0.009 NO3 35 0.56

Cd(II) 0.5 0.017

SUM SUM

Classwork#1


Ca2+ 180 4.49 8.98 HCO3 300 4.92 4.92

Mg2+ 65 2.67 5.34 CO32 40 0.66 1.3

Na+

60 2.61 2.61 SO42

60 0.625 1.25K+ 20 0.51 0.51 Cl 348 9.8 9.8

e(II) 0.5 0.009 0.018 NO3 35 0.56 0.56

Cd(II) 0.5 0.0044 0.0089

SUM 17.49 SUM 17.83

Total Ions Sum, meq/L Acceptable % Difference

0 3.0 0.2

3.0 10.0 2

10 - 800 2 5

Principle of Electroneutrality

Classwork#1


5/8

14131211

10987654321

basic

acidic

neutralUnpolluted rain

Acid Rain

WaterQualityIndicators

pH goodindicatorofnaturalwaterquality importantforaquaFclife sandstone/shalewatersheds~6.0-7.0 limestonewatersheds~7.0-8.0 impactedbyacidrain,minedrainage

Alkalinity measureofresistancetopHchange highinlimestonestreams lowerinheadwaterareas someFmesmeasuredasAcidNeutralizingCapacity(ANC)

AT = [HCO3] + 2[CO3

2] + [B(OH)4] + [OH] + 2[PO4

3] +

[HPO42] + [SiO(OH)3] [H

+]

[HSO4]

Alkalinity


Ca2+ 180 4.49 8.98 HCO3 300 4.92 4.92

Mg2+ 65 2.67 5.34 CO32 40 0.66 1.3

Na+ 60 2.61 2.61 SO42 60 0.625 1.25

K+ 20 0.51 0.51 Cl 348 9.8 9.8

e(II) 0.5 0.009 0.018 NO3 35 0.56 0.56

Cd(II) 0.5 0.0044 0.0089

SUM 17.49 SUM 17.83

WhatisthetotalalkalinityasCaCO3?

Classwork#2


SUM

[Alk]=[HCO3-]+2[CO32-]+[OH-][H+]

Classwork#2


HCO3- 300

SUM

[Alk]=[HCO3-]+2[CO3

2-]+[OH-][H+]

Classwork#2


HCO3- 300 4.92 4.92

SUM

[Alk]=[HCO3-]+2[CO3

2-]+[OH-][H+]

Classwork#2


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HCO3- 300 4.92 4.92

CO32- 40 0.66 1.3

SUM 6.22

Totalalkalinity=6.22meq/L*50mgCaCO3/meq=311mg/LasCaCO3

[Alk]=[HCO3-]+2[CO3

2-]+[OH-][H+]

Classwork#2 WaterQualityIndicators

Totalhardness(mg/LasCaCO3):Ca2+,Mg2+ Totaldissolvedsolids(TDS) ConducFvity:TDS=k*EC Dissolvedoxygen Turbidity(NTU) ParFclecount Stabilityofwater:LangelierSaturaFonIndex(LSI)


Ca2+ 180 4.49 8.98 HCO3 300 4.92 4.92

Mg2+ 65 2.67 5.34 CO32 40 0.66 1.3

Na+ 60 2.61 2.61 SO42 60 0.625 1.25

K+ 20 0.51 0.51 Cl 348 9.8 9.8

e(II) 0.5 0.009 0.018 NO3 35 0.56 0.56

Cd(II) 0.5 0.0044 0.0089

SUM 17.49 SUM 17.83

WhatisthetotalhardnessasCaCO3?

Classwork#3


SUM SUM

Ca2+,Mg2+

Classwork#3


Ca2+ 180

Mg2+ 65

SUM SUM

Classwork#3

Ca2+,Mg2+


Ca2+ 180 4.49

Mg2+ 65 2.67

SUM SUM

Classwork#3

Ca2+,Mg2+


7/8


Ca2+ 180 4.49 8.98

Mg2+ 65 2.67 5.34

SUM 14.32

Totalhardness=14.32meq/L*50mgCaCO3/meq=716mg/LasCaCO3

Ca2+,Mg2+

Classwork#3 Classwork#3

Isithardwater? SoQ: 020mg/Lascalcium ModeratelysoQ: 2040mg/Lascalcium Slight lyhard: 4060mg/Lascalcium Moderatelyhard: 6080mg/Lascalcium Hard: 80120mg/Lascalcium VeryHard >120mg/Lascalcium SoQ: 060mg/LasCaCO3 Moderatelyhard: 60120mg/LasCaCO3 Hard: 120180mg/LasCaCO3 VeryHard >180mg/LasCaCO3

Totalhardness=14.32meq/L*50mgCaCO 3/meq=716mg/LasCaCO 3

Cons7tuents


ChargeHydrophobicity

Solubility, volatility

Organics

Metals & Ligands

Dissolved Species


Size, shape,density

surface charge

Organic: bacteria,

protozoa, virus

Inorganic: clay

(Turbidity)

Particles


SolubilityVolability

Interface (G/L)

Ammonia, chlorine,

ozone, et al.

Oxygen

Carbon dioxide

Gases

Constituents

ProblemsAssociatedwithOrganicCompounds

TurbidityandcolorformaFon DOdepleFon Tasteandodorproblems Interferencewithwatertreatmentprocesses ormaFonofdisinfecFonby-products(DBPs)

NaturalOrganicMaer(NOM)

DerivedfromnaturaldecomposiFonofplantsandanimalmaterials

MacCarthy, 2001, Soil Science., 166, 738-751

NaturalOrganicMaer(NOM)


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ChemicalClass of

Compounds

Associated Compliance Problems

DBP,Chlorination

DBP,Ozonation

BiologicalActivity

C ol or Tr ans por t of Heavy Metals

Taste andOdor

Humic species Major ro le Major ro le

Little impact Major role

Major role

Secondaryimportance

Carbohydrates Not known,probably

insignificant

Probablynot

significant

Major role None Insignificant Insignificant

Amino Acids important May besignificant

Major role Major Secondaryimportance

Insignificant

Proteins important important Major role Major May besignificant

Insignificant

Carboxylicacids

impor tant Generatedby

ozonation

Secondaryimportance

None Insignificant Insignificant

Others PrimarilyGeosmin and

2-MIB

MajorChemicalClassesofNOMCompoundsandAssociatedWaterQualityProblems

ChemicalName Acronym OdorThresholdConc.

(ng/L)

2-methylisoborneol MIB 410

trans-1,10-dimethyl-trans-9-decalol Geosmin 1.310

GeosminMIB

MajorChemicalClassesofNOMCompoundsandAssociatedWaterQualityProblems

Class of DBP Class of NOM Compounds

Humic Species Carbohydrates Amino Acids Proteins Carboxylic Acids

Trihalomethanes (THM) Primary source Not known,probably minor

minor Important Secondary source

Haloacetic Acids (HAA) Primary source Not known,probably minor

Not known,probablyinsignificant

Not known, maybe significant

Secondary source

Chlorophenols Primary source Insignificant Insignificant Insignificant Insignificant

Haloketones Primary source Not known, maybe significant


Not known, maybe significant

Insignificant

Chloral Hydrate Primary source Not known,probablyinsignificant



Insignificant

Haloacetonitriles Important Not known,probablyinsignificant

Important Important Insignificant

Trihalonitromethane Important Not known,probablyinsignificant


Cyanogen halide Important Not known,probably

insignificant


Aldehdes Primary source Not known, maybe significant


Important

NOMandDisinfec7onBy-products(DBPs)

surfactants pesFcides(i.e.,herbicides,insecFcides) cleaningsolvents polychlorinatedbiphenyls(PCBs) disinfecFonsby-products(i.e.,THM,HAA)

Synthe7cOrganicCompounds(SOC)

Microorganisms

Bacteria:0.1-10m Viruses:0.01-0.1m Protozoa(i.e.,giardia,cryptosporidium):2-15m ungiandmolds Algae Helminths(parasiFcworms)

supplemental lecture 1 water constituents

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