Onsite Drinking Water Onsite Drinking Water TreatmentTreatment

Acknowledgement

• Guidance and assistance on development of this presentation was provided by the Texas Groundwater Protection Committee and the Texas Commission on Environmental Quality.  The effort was partially funded by the U.S. Environmental Protection Agency

OverviewOverview IntroductionIntroductionContaminates of concernContaminates of concern

• Public health issuesPublic health issues

• Maximum contaminant level (MCL)Maximum contaminant level (MCL)

• Areas of concernAreas of concern

• Treatment OptionsTreatment OptionsHow to select a treatment unitHow to select a treatment unitResourcesResources

IntroductionIntroduction

Groundwater provides a large portion of our Groundwater provides a large portion of our drinking water.drinking water.

Fifteen percent of Americans have their Fifteen percent of Americans have their own sources of drinking water.own sources of drinking water.

It is up to well owners to ensure their water It is up to well owners to ensure their water is safe to drink.is safe to drink.

How do Aquifers Become How do Aquifers Become Polluted?Polluted?

Aquifers become polluted through Aquifers become polluted through

• Leaching from rocksLeaching from rocks

• Pollutants carried down from the surface Pollutants carried down from the surface by percolating waterby percolating water

• Surface water rechargeSurface water recharge

• Interaquifer exchangeInteraquifer exchange

• Direct mitigationDirect mitigation

Drinking Water QualityDrinking Water Quality

EPA rules do not apply to private wells; EPA rules do not apply to private wells; however, EPA standards are a good basis however, EPA standards are a good basis for determining what your drinking water for determining what your drinking water quality should be.quality should be.

MCL - Maximum contaminant level MCL - Maximum contaminant level

Water Quality StandardsWater Quality StandardsNational Primary Drinking Water RegulationsNational Primary Drinking Water Regulations

• Protect public healthProtect public health

National Secondary Drinking Water RegulationsNational Secondary Drinking Water Regulations

• Aesthetic or cosmetic effectsAesthetic or cosmetic effects

Contaminant Candidate List (CCL)Contaminant Candidate List (CCL)

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

Contaminants of ConcernContaminants of Concern

ArsenicArsenicNitrateNitratePerchloratePerchlorateRadionuclidesRadionuclides

ArsenicArsenic

Arsenic - What is It?Arsenic - What is It?

Naturally occurring element Naturally occurring element

Natural sourcesNatural sources• Erosion, dissolution, and weathering of rocksErosion, dissolution, and weathering of rocks• VolcanoesVolcanoes• Forest firesForest fires

Manmade/man-affected sourcesManmade/man-affected sources• AgricultureAgriculture• Wood preservativesWood preservatives

Acute Acute Stomach pain, nausea, vomiting, diarrhea Stomach pain, nausea, vomiting, diarrhea Numbness in hands and feet Numbness in hands and feet Periorbital swellingPeriorbital swelling

ChronicChronic Dermal EffectsDermal Effects HypertensionHypertension Cardiovascular EffectsCardiovascular Effects

Arsenic - Health RisksArsenic - Health Risks

DiabetesDiabetesCancerCancer

Arsenic - MCLArsenic - MCL

The new Maximum Contaminant Level The new Maximum Contaminant Level (MCL) for arsenic is 10 (MCL) for arsenic is 10 ppbppb..

The EPA estimates that 350,000 people in The EPA estimates that 350,000 people in the U.S. drink water containing more than the U.S. drink water containing more than 50 50 ppbppb, and nearly 25 million people drink , and nearly 25 million people drink water containing more than 25 water containing more than 25 ppbppb..

Arsenic Concentrations

in Texas

High Arsenic Concentrations in

Texas Groundwater

High Arsenic Concentrations

in the High Plains Aquifer

High Arsenic Concentrations in the Gulf Coast Aquifer

Arsenic - TreatmentArsenic - Treatment

Treatment is dependent on oxidation stateTreatment is dependent on oxidation state

Arsenate - As(V) Arsenate - As(V) • Effective removal Effective removal

Arsenite – As(III)Arsenite – As(III)• Must undergo oxidationMust undergo oxidation

to be effectively removedto be effectively removed

Arsenic – Treatment OptionsArsenic – Treatment Options

AdsorptionAdsorptionReverse Osmosis (RO)Reverse Osmosis (RO)DistillationDistillationIon Exchange (IE)Ion Exchange (IE)

Arsenic - AdsorptionArsenic - Adsorption Activated alumina and Activated alumina and

iron-based sorbents iron-based sorbents

AdvantagesAdvantages Simple operationSimple operation Low maintenanceLow maintenance Low relative cost Low relative cost Small under-the-counter Small under-the-counter

footprintfootprint Slow breakthrough Slow breakthrough

kineticskinetics

Arsenic - Reverse OsmosisArsenic - Reverse OsmosisAdvantageAdvantage

Achieves greater than 95% removalAchieves greater than 95% removal

DisadvantageDisadvantage Relatively poor water recoveryRelatively poor water recovery

• Most units designed to achieve 20-30% recovery Most units designed to achieve 20-30% recovery • Used to treat drinking and cooking water onlyUsed to treat drinking and cooking water only

Arsenic - Reverse OsmosisArsenic - Reverse Osmosis

Arsenic - DistillationArsenic - Distillation

Arsenic - DistillationArsenic - Distillation

Majority of the cost is associated with energy requirementMajority of the cost is associated with energy requirement

ExampleExample

Distillation units can be purchased for $300-$1200Distillation units can be purchased for $300-$1200

($/kWh)y electricit ofcost )/(Production

unitofWattage024.0/

daygalgalCost

galdaygal

/13.0$$0.07/kWh/15

1100024.0

Arsenic - Ion ExchangeArsenic - Ion ExchangeRemoval based on the principle of Removal based on the principle of

charged particles (ions)charged particles (ions)• A positively charged particle is called a A positively charged particle is called a

CATION.CATION.• A negatively charged particle is called an A negatively charged particle is called an

ANION.ANION.

Cations and anions are attracted to each Cations and anions are attracted to each other.other.

Ion Exchange

Arsenic - Ion ExchangeArsenic - Ion Exchange

Not a good option if source water containsNot a good option if source water contains > 500 mg/L of TDS, > 500 mg/L of TDS, > 50 mg/L SO> 50 mg/L SO44

-2 -2 (sulfate)(sulfate)

high levels of nitrate or ironhigh levels of nitrate or iron

Chromatographic peaking Chromatographic peaking

NitrateNitrate

NONO33--

Nitrate- What is It?Nitrate- What is It?

Occurs naturally in both surface and groundwaterOccurs naturally in both surface and groundwater

Groundwater concentrations are elevated by Groundwater concentrations are elevated by • Natural occurrenceNatural occurrence• Overuse of fertilizersOveruse of fertilizers• Improper disposal of human and animal wasteImproper disposal of human and animal waste

Very soluble in waterVery soluble in water

Nitrate – Health RisksNitrate – Health Risks

In the United States, the average dietary intake of In the United States, the average dietary intake of nitrate is about 75 to 100 mg per day. nitrate is about 75 to 100 mg per day. 5 to 10% comes from drinking water 5 to 10% comes from drinking water

In the body In the body nitratenitrate converts to converts to nitrite.nitrite. Conversion process oxidizes the iron in hemoglobin Conversion process oxidizes the iron in hemoglobin For children For children 6 months or younger6 months or younger - results in a blue baby - results in a blue baby

syndrome. syndrome.

Elevated nitrite intake may contribute to some cancersElevated nitrite intake may contribute to some cancers

Nitrate - MCLNitrate - MCL

Drinking Water Standards (ppm): Drinking Water Standards (ppm):

MCLMCLNitrate:Nitrate: 10 as N10 as N Nitrite:Nitrite: 1 as N1 as N

Nitrate Concentrations in TexasNitrate Concentrations in Texas

High Nitrate Concentrations

in Texas Groundwater

High Nitrate Concentrations in West Texas Groundwater

Nitrate – Treatment OptionsNitrate – Treatment Options

Reverse Osmosis (RO)Reverse Osmosis (RO)DistillationDistillationIon Exchange (IE)Ion Exchange (IE)ElectrodialysisElectrodialysis

ElectrodialysisElectrodialysis

Alternating anion- and Alternating anion- and cation-selective stacked cation-selective stacked membranesmembranes

Nitrate drawn into the Nitrate drawn into the brine wastebrine waste

DisadvantagesDisadvantages Complicated Complicated Costly Costly Potentially prohibited by Potentially prohibited by

local codeslocal codes

PerchloratePerchlorate

ClOClO44

Perchlorate – What is It?Perchlorate – What is It?

Natural occurring and manmade chemical Natural occurring and manmade chemical Very mobile in aqueous systemsVery mobile in aqueous systemsSources of contaminationSources of contamination

Fertilizer derived from Chilean caliche Fertilizer derived from Chilean caliche Ingredient in solid propellant for rockets, Ingredient in solid propellant for rockets,

missiles, and fireworksmissiles, and fireworks Naturally occurringNaturally occurring

Perchlorate – Health RiskPerchlorate – Health RiskEffect of low level chronic exposure is still Effect of low level chronic exposure is still

not fully understood not fully understood

Exposure to perchlorate is via the diet Exposure to perchlorate is via the diet Examples: Lettuce, milk, and drinking water Examples: Lettuce, milk, and drinking water

Competitively blocks thyroid iodine uptakeCompetitively blocks thyroid iodine uptake Sensitive populations: fetuses, newborns, Sensitive populations: fetuses, newborns,

infants, young children, individuals with thyroid infants, young children, individuals with thyroid problems or iodide deficiencies. problems or iodide deficiencies.

Perchlorate – MCLPerchlorate – MCL

No MCL No MCL

EPA reference dose is .0007 mg/kg per dayEPA reference dose is .0007 mg/kg per day

In Texas, current action level is 17 ppbIn Texas, current action level is 17 ppb 4 ppb is used for public water systems.4 ppb is used for public water systems.

Perchlorate Occurrence in TXPerchlorate Occurrence in TX

High Perchlorate Concentrations in the High Plains Aquifer

Occurrence and Potential Sources of Perchlorate Occurrence and Potential Sources of Perchlorate Releases to the Environment as of April 2003Releases to the Environment as of April 2003

LocationLocation SuspectedSuspected

SourceSource

Type of Type of

ContaminationContamination

Max.Max.Concentration Concentration

(ppb)(ppb)

Andrews CountyAndrews County UnknownUnknown Public Water SupplyPublic Water Supply 15.815.8

Dawson CountyDawson County UnknownUnknown Public Water SupplyPublic Water Supply

Private WellPrivate Well2626

58.858.8Ector CountyEctor County UnknownUnknown Public Water SupplyPublic Water Supply 55

Gaines CountyGaines County UnknownUnknown Public Water SupplyPublic Water Supply

Private WellPrivate Well2727

3030Glasscock Glasscock CountyCounty

UnknownUnknown Public Water SupplyPublic Water Supply

Private WellPrivate Well1.11.1

33

Occurrence and Potential Sources of Perchlorate Occurrence and Potential Sources of Perchlorate Releases to the Environment as of April 2003Releases to the Environment as of April 2003

LocationLocation SuspectedSuspected

SourceSource

Type of Type of

ContaminationContamination

Max.Max.Concentration Concentration

(ppb)(ppb)

Howard CountyHoward County UnknownUnknown Public Water SupplyPublic Water Supply

Private WellPrivate Well1.41.4

2626Kleburg CountyKleburg County UnknownUnknown Public Water SupplyPublic Water Supply 4.54.5Hockley CountyHockley County Improper Improper

Cathodic Cathodic ProtectionProtection

Elevated Storage Elevated Storage TankTank

3232

Lone Star Army Lone Star Army Ammunition Ammunition Plant, TexarkanaPlant, Texarkana

Propellant and Propellant and Munitions Munitions HandlingHandling

Monitoring WellMonitoring Well

Surface WaterSurface Water2323

66Longhorn Army Longhorn Army Ammunition Ammunition Depot, KamakDepot, Kamak

Propellant Propellant HandlingHandling

Monitoring WellMonitoring Well 169,000169,000

Occurrence and Potential Sources of Perchlorate Occurrence and Potential Sources of Perchlorate Releases to the Environment as of April 2003Releases to the Environment as of April 2003

LocationLocation SuspectedSuspected

SourceSource

Type of Type of

ContaminationContamination

Max.Max.Concentration Concentration

(ppb)(ppb)

Martin CountyMartin County UnknownUnknown Public Water SupplyPublic Water Supply

Private WellPrivate Well3232

19.119.1McGregor Naval McGregor Naval Weapons PlantWeapons Plant

Propellant Propellant HandlingHandling

Monitoring WellMonitoring Well 91,00091,000

Midland CountyMidland County UnknownUnknown Public Water SupplyPublic Water Supply 4646PANTEX Plant, PANTEX Plant, AmarilloAmarillo

ExplosivesExplosives Monitoring WellMonitoring Well 340340

Red River Army Red River Army Depot, Depot, TexarkanaTexarkana

Propellant Propellant HandlingHandling

Monitoring WellMonitoring Well 8080

Perchlorate – Treatment OptionsPerchlorate – Treatment Options

Reverse OsmosisReverse Osmosis

Ion ExchangeIon Exchange Resin cannot be regenerated Resin cannot be regenerated

RadionuclidesRadionuclides

Radionuclides –What are They?Radionuclides –What are They?

Radioactive materialRadioactive material (Adjusted) Gross Alpha Emitters(Adjusted) Gross Alpha Emitters

• Positively charged Positively charged • Uranium and Radium-226 are examplesUranium and Radium-226 are examples

Beta particle emittersBeta particle emitters• Positively or negatively charged Positively or negatively charged • Radium-228 and TRadium-228 and Tritium are examplesare examples

RadonRadon• GasGas

Radionuclides –How do They End Up Radionuclides –How do They End Up in My Water?in My Water?

Mostly naturally occurring Mostly naturally occurring From the Earth’s crust (released as the rocks From the Earth’s crust (released as the rocks

weather)weather) In the atmosphere (comes down with rain)In the atmosphere (comes down with rain)

Some manmade sourcesSome manmade sources

Radionuclides lead to an increased risk of cancerRadionuclides lead to an increased risk of cancerUranium: kidney damageUranium: kidney damageRadiumRadium

Bone growths Bone growths Osteoporosis Osteoporosis Tooth breakage Tooth breakage Kidney disease Kidney disease Liver diseaseLiver disease

Radon-lung and stomach cancerRadon-lung and stomach cancer

Radionuclides –Health RisksRadionuclides –Health Risks

Tissue necrosisTissue necrosis Cataracts Cataracts Anemia Anemia Immunological suppression Immunological suppression Death Death

Beta- and Photon-Emitters: 4 millirems / yearBeta- and Photon-Emitters: 4 millirems / year

Alpha-Emitters: 15 pCi/L Alpha-Emitters: 15 pCi/L

Uranium: Uranium: 30 30 µµg/Lg/L

Radium: 5 pCi/L Radium: 5 pCi/L

Radon: No current MCL (may become 4,000 pCi/L or Radon: No current MCL (may become 4,000 pCi/L or 300 pCi/L depending on state’s decision)300 pCi/L depending on state’s decision)

Radionuclides –MCLRadionuclides –MCL

Gross Alpha Particle Activity in Texas Water Wells 1988-2004

Gross Beta Particle Activity in Texas Water Wells 1988-2004

High Radionuclides in

Texas Groundwater

High Radionuclides in Texas Groundwater

Radionuclides –Treatment Radionuclides –Treatment OptionsOptions

ContaminantContaminant Treatment TechnologyTreatment Technology

Radium (-226 and-228)Radium (-226 and-228) Ion Exchange (IE)- cation; Ion Exchange (IE)- cation; Reverse Osmosis (RO); Reverse Osmosis (RO); Distillation (D)Distillation (D)

Radon-222Radon-222 Aeration;Aeration; Granular Activated Granular Activated Carbon (GAC) Carbon (GAC)

UraniumUranium IE -anion; RO; DIE -anion; RO; D

Adjusted gross alpha Adjusted gross alpha emittersemitters

RO; DRO; D

Gross beta and photon Gross beta and photon emittersemitters

IE-mixed bed; RO; DIE-mixed bed; RO; D

Radon RemovalRadon Removal

Granular activated carbon (GAC)Granular activated carbon (GAC) Do not use point-of-use systems Do not use point-of-use systems

AerationAeration Preferred method of removalPreferred method of removal Up to 99.9% removalUp to 99.9% removal Three main typesThree main types

• Spray aeration Spray aeration • Packed column aerationPacked column aeration• Shallow tray aerationShallow tray aeration

Spray Spray AerationAeration

Packed Packed Column Column AerationAeration

Shallow Shallow Tray Tray

AerationAeration

Which Treatment Which Treatment Option Should I Option Should I

Choose?Choose?

Treatment Options SummaryTreatment Options Summary

TechnologyTechnology Contaminants*Contaminants* Initial Initial CostCost±±

LimitationsLimitations

Ion Ion ExchangeExchange

arsenic (As), arsenic (As), perchlorate (P), nitrate perchlorate (P), nitrate (N), radium (R), (N), radium (R), uranium (U), gross uranium (U), gross beta emitters (beta emitters (ββ))

$400- $400- $1500$1500

competing competing contaminantscontaminants

Reverse Reverse OsmosisOsmosis

As, P, N, U, R, As, P, N, U, R, ββ, , adjusted alpha adjusted alpha

emitters (emitters (αα))

$300-$300-$1000$1000

poor water poor water recoveryrecovery

DistillationDistillation As, N, R, UAs, N, R, U $300-$300-$1200$1200

energy energy requirementrequirement

* Does not imply co-treatment capabilities for all contaminants listed.

± Only estimate of unit cost– does not include installation or O & M costs.

Treatment Options SummaryTreatment Options Summary

TechnologyTechnology ContaminantsContaminants Initial CostInitial Cost±± LimitationsLimitations

AerationAeration radonradon $3000-$3000- off-gasoff-gas

AdsorptionAdsorption•AA & IBSAA & IBS

•GACGAC

AsAs

radonradon

$100-$300$100-$300

$300-$800$300-$800

microbial microbial growthgrowth

aeration is a aeration is a better better choicechoice

± Only estimate of unit cost– does not include installation or O & M costs.

Selecting a Treatment UnitSelecting a Treatment Unit

Qualified third-party lab water quality testing Qualified third-party lab water quality testing http://www.tnrcc.state.tx.us/permitting/waterperm/pdw/chemlabs.pdf

Find a system that will treat the constituents in Find a system that will treat the constituents in the water the water

Consider co-treatment compatibility if more than Consider co-treatment compatibility if more than one constituent is presentone constituent is present

Selecting a Treatment UnitSelecting a Treatment Unit

CompareCompare Initial costInitial cost O&M costs O&M costs O&M requirementsO&M requirements Contaminant removal efficiency Contaminant removal efficiency

Will you have a means of waste disposal?Will you have a means of waste disposal?

WarrantiesWarranties

Life expectancy Life expectancy

Company reputationCompany reputation

Product CertificationProduct CertificationWater Quality Association (WQA) Water Quality Association (WQA)

Gold Seal Product Validation from the WQAGold Seal Product Validation from the WQA http://www.wqa.orghttp://www.wqa.org

The National Sanitation Foundation (NSF)The National Sanitation Foundation (NSF) http://www.nsf.org/Certified/DWTU/http://www.nsf.org/Certified/DWTU/

EPA registrationEPA registration

Need More Information?Need More Information? Environmental Protection AgencyEnvironmental Protection Agency

www.epa.gov/safewater/www.epa.gov/safewater/

Safe Drinking Water HotlineSafe Drinking Water Hotline (1-800-426-4791) (1-800-426-4791) www.epa.gov/surfwww.epa.gov/surf““Drinking Water From Household Wells”Drinking Water From Household Wells”““Home Water Treatment Units”Home Water Treatment Units”

Contact your County Extension OfficeContact your County Extension Office