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Water QualityWater QualityFreshman Clinic IIFreshman Clinic II

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01885 1895 1905 1915 1925 1935

Filtration, 1905

Chlorination, 1905

Adopted fromASCE

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Safe Drinking Water Act of 1974Safe Drinking Water Act of 1974

Ensure public water supply Ensure public water supply systems meet minimum standards systems meet minimum standards for protection of for protection of public healthpublic health– Primary RegulationsPrimary Regulations– Secondary RegulationsSecondary Regulations

http://www.epa.gov/safewater/mcl.html

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Primary Drinking Water Primary Drinking Water StandardsStandards

Protection of human healthProtection of human health– Maximum Contaminant Level GoalMaximum Contaminant Level Goal

Nonenforceable health goalNonenforceable health goal What we’d like to achieveWhat we’d like to achieve

– Maximum Contaminant LevelMaximum Contaminant Level Set as close to MCLG as feasible Set as close to MCLG as feasible

(tech/cost)(tech/cost) Violation requires corrective actionViolation requires corrective action

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Primary StandardsPrimary Standards

OrganicsOrganics– Pesticides, Solvents, Fuels...Pesticides, Solvents, Fuels...

InorganicsInorganics– metals...metals...

RadionuclidesRadionuclides– Beta particles, alpha particles, radon...Beta particles, alpha particles, radon...

MicrobialsMicrobials– viruses, bacteria, protozoa, helminthsviruses, bacteria, protozoa, helminths

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Example ContaminantsExample ContaminantsContaminaContaminantnt

MCLGMCLG MCLMCL Health EffectHealth Effect CauseCause

BenzeneBenzene ZeroZero 0.005 0.005 mg/Lmg/L

Risk of CancerRisk of Cancer Factories, Gasoline, Factories, Gasoline, LandfillsLandfills

CadmiumCadmium 0.005 0.005 mg/Lmg/L

0.005 0.005 mg/Lmg/L

Kidney Kidney DamageDamage

Galvanized pipes, Galvanized pipes, Erosion of natural Erosion of natural deposits, Metal deposits, Metal refineries, Batteries, refineries, Batteries, PaintsPaints

Alpha Alpha ParticlesParticles

ZeroZero 15 15 picocuriespicocuries/Liter /Liter (pCi/L)(pCi/L)

Risk of CancerRisk of Cancer Erosion of natural Erosion of natural depositsdeposits

Giardia Giardia LambliaLamblia

ZeroZero TTTT GastrointestionGastrointestional Illnessal Illness

Human or animal fecal Human or animal fecal mattermatter

TT – Treatment Technology (filtration and disinfection, or alternative that achieves 99.9% removal/inactivation)

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Aside - UnitsAside - Units

ConcentrationConcentration– mg/l (milligrams per liter)mg/l (milligrams per liter)

milli = 1/1,000milli = 1/1,000

– ug/l or ug/l or g/l (micrograms per liter)g/l (micrograms per liter) micro = 1/1,000,000micro = 1/1,000,000

– pCi/l (picocuries per liter)pCi/l (picocuries per liter) pico = 1/1,000,000,000,000pico = 1/1,000,000,000,000 The curie is equal to 37 billion disintegrations per The curie is equal to 37 billion disintegrations per

second, approximately the activity of 1 gram of second, approximately the activity of 1 gram of radiumradium

Microbial PathogensMicrobial Pathogens

Tiny living organisms that cause diseaseTiny living organisms that cause disease Can be Can be

– VirusesViruses– BacteriaBacteria– ProtozoaProtozoa– HelminthsHelminths

But not all viruses, But not all viruses, bacteria, protozoa, and bacteria, protozoa, and helminths are pathogenshelminths are pathogens

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MeasurementMeasurement

Organics and InorganicsOrganics and Inorganics– measure for specific compoundmeasure for specific compound

HPLC, GC, GC-Mass Spec, AA, IC…HPLC, GC, GC-Mass Spec, AA, IC…

RadionuclidesRadionuclides– Conduct gross tests, then specific Conduct gross tests, then specific

teststests MicrobesMicrobes

– Measure indicator organismsMeasure indicator organisms

IndicatorIndicator organismsorganisms

Too difficult to identify all pathogens, Too difficult to identify all pathogens, so we use indicator organisms so we use indicator organisms – May not be pathogens themselvesMay not be pathogens themselves

If you find indicator organisms If you find indicator organisms – sample might be pathogen sample might be pathogen

contaminatedcontaminated If you don’t If you don’t

– very unlikely sample is contaminatedvery unlikely sample is contaminated

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CommonCommon Indicator Organisms Indicator Organisms

Total ColiformTotal Coliform Fecal ColiformFecal Coliform Escherichia coliEscherichia coli

Common denominator is fecal Common denominator is fecal coliformcoliform– found in intestinesfound in intestines– evidence of fecal contaminationevidence of fecal contamination

http://www.cellsalive.com/

E. Coli

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Secondary Drinking Water Secondary Drinking Water StandardsStandards

Not health relatedNot health related Not enforceableNot enforceable Based onBased on

– Aesthetics Aesthetics Color, odor, taste, foaming…Color, odor, taste, foaming…

– Cosmetic effectsCosmetic effects Skin or tooth discolorationSkin or tooth discoloration

– Technical effectsTechnical effects Corrosivity, staining, scaling, Corrosivity, staining, scaling,

sedimentationsedimentation

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Examples of Secondary Examples of Secondary StandardsStandards

PARAMETERPARAMETER GOALGOAL REASONREASONChloride Chloride 250 mg/L 250 mg/L salty taste salty taste Copper Copper 1.0 mg/L 1.0 mg/L metallic taste; blue-green staining metallic taste; blue-green staining Corrosivity Corrosivity Non-corrosive Non-corrosive metallic taste; corroded pipes/ fixtures metallic taste; corroded pipes/ fixtures

staining staining Fluoride Fluoride 2.0 mg/L 2.0 mg/L tooth discoloration tooth discoloration Foaming agents Foaming agents 0.5 mg/L 0.5 mg/L frothy, cloudy; bitter taste; odor frothy, cloudy; bitter taste; odor Iron Iron 0.3 mg/L 0.3 mg/L rusty color; sediment; metallic taste; rusty color; sediment; metallic taste;

reddish or orange staining reddish or orange staining pH pH 6.5 - 8.5 6.5 - 8.5 low pH: bitter metallic taste; corrosion low pH: bitter metallic taste; corrosion

high pH: slippery feel; soda taste; depositshigh pH: slippery feel; soda taste; deposits Silver Silver 0.1 mg/L 0.1 mg/L skin discoloration; skin discoloration;

graying of the white graying of the white part of the eye part of the eye

Sulfate Sulfate 250 mg/L 250 mg/L salty taste salty taste Total Dissolved Solids (TDS) 500 mg/L Total Dissolved Solids (TDS) 500 mg/L hardness; deposits; hardness; deposits;

colored water; colored water; staining; salty taste staining; salty taste

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OdorOdor Threshold odor number (TON)Threshold odor number (TON)

– Goal is < 3 TONGoal is < 3 TON– Determined by panels of “smellers” Determined by panels of “smellers”

identifying the most dilute sample identifying the most dilute sample they can smellthey can smell

A = ml sample A = ml sample B = ml odor-free waterB = ml odor-free water

TON = (A + B) / A

another secondary standard

Electronic Noses are finding more application

ColorColor Goal is < 15 color unitsGoal is < 15 color units True ColorTrue Color

– vegetable or organic extracts that are vegetable or organic extracts that are dissolved or too small to filterdissolved or too small to filter

Also called “natural color”, usually Also called “natural color”, usually yellowish-brownyellowish-brown

South Jersey rivers have lots of true South Jersey rivers have lots of true colorcolor

Apparent ColorApparent Color– suspended matter, such as red claysuspended matter, such as red clay– Can be filtered outCan be filtered out

another secondary standard

Color MeasurementColor Measurement TraditionalTraditional

– chemical solutions that produce color chemical solutions that produce color similar to natural colorsimilar to natural color

Platinum Cobalt Color UnitsPlatinum Cobalt Color Units

– start w/ 500 mg/L solution Kstart w/ 500 mg/L solution K22PtClPtCl

66

– add sufficient cobalt chloride to provide proper tint add sufficient cobalt chloride to provide proper tint

– dilute to produce working standardsdilute to produce working standards

1 mg/L of K1 mg/L of K22PtClPtCl

66 = 1 platinum cobalt unit = 1 platinum cobalt unit

ModernModern– Use a spectrophotometerUse a spectrophotometer

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SpectrophotometerSpectrophotometer

Hach model DR/4000 UV VISwww.hach.com

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Light AbsorbanceLight Absorbance

Many solutions absorb lightMany solutions absorb light Amount of absorbance function of Amount of absorbance function of

– chemicals in solution and their chemicals in solution and their concentrationconcentration

– distance light travels through solutiondistance light travels through solution– wavelength of lightwavelength of light

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SpectrophotometrySpectrophotometry Widely used Widely used Accurate and sensitiveAccurate and sensitive Absorbance of light used to measure Absorbance of light used to measure

concentration of light absorbing concentration of light absorbing compoundscompounds– If compound itself doesn’t absorb light, If compound itself doesn’t absorb light,

reactant is added that converts it to some reactant is added that converts it to some other (light absorbing) compoundother (light absorbing) compound

Red solutions are red because they absorb blue light

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Beer-Lambert lawBeer-Lambert law

Amount of light absorbed is proportional to Amount of light absorbed is proportional to number of molecules of absorbing number of molecules of absorbing substance in light pathsubstance in light path

Absorbtion proportional to Absorbtion proportional to – concentration of chromogen concentration of chromogen

(light absorbing compound) (light absorbing compound) – length of light path through length of light path through

solution solution

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I and II and I00 = intensity of transmitted light in presence / = intensity of transmitted light in presence /

absence of chromogen, respectivelyabsence of chromogen, respectively c = concentration of chromogenc = concentration of chromogen l = length of light path through solutionl = length of light path through solution K = constant, characteristic for each absorbing K = constant, characteristic for each absorbing

substance at a specified wavelength of light and in a substance at a specified wavelength of light and in a specific solvent (often water)specific solvent (often water)

light transmission = I/Ilight transmission = I/I00, usually reported as a percent, usually reported as a percent

Absorbance (Abs) is used more frequentlyAbsorbance (Abs) is used more frequently

-log-log1010(I/I(I/I00) = K c l) = K c l

Abs = -logAbs = -log1010(I/I(I/I00))

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Hach model DR/4000 UV VIS

Uses Deuterium Lamp and Uses Deuterium Lamp and gas filled Tungsten Lamp gas filled Tungsten Lamp

Narrows light down to a Narrows light down to a specific wavelength using specific wavelength using a monochromatora monochromator

Detects the difference in Detects the difference in light through a solution light through a solution photoelectrically and photoelectrically and compares that difference compares that difference electronicallyelectronically

The difference is The difference is expressed as percent expressed as percent transmission or transmission or absorbanceabsorbance

www.hach.com

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carefully made solution containerscarefully made solution containers plane, parallel sides plane, parallel sides

ensure light path ensure light path is same through is same through all portions, making it all portions, making it possible to tabulate possible to tabulate values of K for various values of K for various substances in various substances in various solvents and wavelengthssolvents and wavelengths

cells or cuvettescells or cuvettes

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Color and SpectrophotometryColor and Spectrophotometry

We can measure color in water We can measure color in water samples using a specific samples using a specific wavelength of lightwavelength of light

Measure true color of filtered waterMeasure true color of filtered water Measure apparent color of Measure apparent color of

unfiltered waterunfiltered water

TurbidityTurbidity Clarity of waterClarity of water CauseCause

– Soil runoff, resulting in scattering of light by Soil runoff, resulting in scattering of light by colloidal particles colloidal particles

colloidal particles are 0.001 to 1 colloidal particles are 0.001 to 1 mm

Why do we care?Why do we care?– Clarity relates to cleanliness Clarity relates to cleanliness – Affects treatment success of disinfectionAffects treatment success of disinfection

MeasurementMeasurement– light transmission with standard light source, 90light transmission with standard light source, 90oo

detector, and glass containerdetector, and glass container Measured in NTU (Nephelometric Turbidity Units)Measured in NTU (Nephelometric Turbidity Units)

Some NTU NumbersSome NTU Numbers

> 5 NTU's> 5 NTU's

< 0.1 NTU < 0.1 NTU

Surface water typical valuesSurface water typical values– 11 NTU11 NTU– 16 NTU16 NTU– 26 NTU26 NTU

Detected visually Detected visually Aesthetically objectionableAesthetically objectionable

Properly treated waterProperly treated water

ReservoirReservoirLakeLakeRiverRiver

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Turbidity StandardTurbidity Standard

Primary drinking water standardPrimary drinking water standard– Turbidity may never exceed 1 NTU, and Turbidity may never exceed 1 NTU, and

must not exceed 0.3 NTU in 95% of daily must not exceed 0.3 NTU in 95% of daily samples in any monthsamples in any month

Why primary?Why primary?– Because water with low turbidity is less Because water with low turbidity is less

likely to be contaminated by pathogens likely to be contaminated by pathogens and disinfects easierand disinfects easier

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Hach 2100N Laboratory Hach 2100N Laboratory TurbidimeterTurbidimeter

www.hach.com

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TurbidimeterTurbidimeter

Micro-processor-based modelMicro-processor-based model Employs advanced optical Employs advanced optical

and electronic designand electronic design Has two types of sensorsHas two types of sensors

– Scattering SensorScattering Sensor– Transmissive SensorTransmissive Sensor

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Turbidity TestTurbidity Test

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WebsitesWebsites EPA Office of WaterEPA Office of Water

– www.epa.gov/OW/www.epa.gov/OW/ Water Quality CompanyWater Quality Company

– www.hach.comwww.hach.com Frequently asked questions about water qualityFrequently asked questions about water quality

– www.sioxlan.comwww.sioxlan.com Water Environment FederationWater Environment Federation

– www.wef.orgwww.wef.org American Water Works AssociationAmerican Water Works Association

– www.awwa.orgwww.awwa.org Info on water treatment processesInfo on water treatment processes

– www.culligan.comwww.culligan.com