WATER TECHNOLOGIES FOR RURAL TEXAS OFFICE OF RURAL COMMUNITY AFFAIRS Cryptosporidium: Technologies...
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Transcript of WATER TECHNOLOGIES FOR RURAL TEXAS OFFICE OF RURAL COMMUNITY AFFAIRS Cryptosporidium: Technologies...
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Cryptosporidium: Cryptosporidium: Technologies for Disinfection, Technologies for Disinfection,
Particulate Removal & Particulate Removal & By-Product ManagementBy-Product Management
Presented byPresented by
Roger K. Noack, P.E.Roger K. Noack, P.E.
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Outline of PresentationOutline of Presentation
• History/BackgroundHistory/Background
• RegulationsRegulations
• Treatment Technologies AvailableTreatment Technologies Available
• Treatment Technologies LimitationsTreatment Technologies Limitations
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
HistoryHistory
• 1945 – Texas requires disinfection1945 – Texas requires disinfection
• 1974 – SDWA promulgated1974 – SDWA promulgated
• 1979 – THM Rule1979 – THM Rule
• 1986 – SDWA Amendments1986 – SDWA Amendments
• 1993 – Milwaukee 1993 – Milwaukee CryptosporidiosisCryptosporidiosis outbreakoutbreak
• 1996 – SDWA Amendments1996 – SDWA Amendments
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
BackgroundBackground
• Multiple Barrier ApproachMultiple Barrier Approach– Source WaterSource Water– TreatmentTreatment
• RemovalRemoval• DisinfectionDisinfection
– DistributionDistribution
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
RegulationsRegulations
• Microbiological ContaminationMicrobiological Contamination– Giardia – 3-log removal/inactivationGiardia – 3-log removal/inactivation– Viruses – 4-log removal/inactivationViruses – 4-log removal/inactivation– Cryptosporidium – 2-log removalCryptosporidium – 2-log removal– Turbidity – 0.3 NTU in 95% of samplesTurbidity – 0.3 NTU in 95% of samples
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
RegulationsRegulations
• Disinfection and Disinfection By-ProductsDisinfection and Disinfection By-Products– CT (disinfectant Concentration x contact Time )CT (disinfectant Concentration x contact Time )– Maximum Disinfectant Residual LevelMaximum Disinfectant Residual Level– Total TrihalomethanesTotal Trihalomethanes– Haloacetic AcidsHaloacetic Acids– ChloriteChlorite– BromateBromate– Total Organic CarbonTotal Organic Carbon
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Simultaneous ComplianceSimultaneous Compliance
• Producing drinking water that meets all Producing drinking water that meets all regulatory requirementsregulatory requirements
• ALL RULES ARE EQUALALL RULES ARE EQUAL
• One rule cannot be undermined in favor One rule cannot be undermined in favor of anotherof another
• Simultaneous compliance will be Simultaneous compliance will be challengechallenge
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
DisinfectionDisinfection
• ChlorineChlorine– LiquidLiquid– TabletTablet– GasGas– On-site generationOn-site generation
• Chloramine (chlorine + ammonia)Chloramine (chlorine + ammonia)– LiquidLiquid– GasGas
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
DisinfectionDisinfection
• Ozone Ozone
• Chlorine dioxideChlorine dioxide
• Ultraviolet lightUltraviolet light
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Limitations of DisinfectantsLimitations of Disinfectants
• ChlorineChlorine– Contact timeContact time– DBPsDBPs– Demand versus residualDemand versus residual– SafetySafety
• ChloraminesChloramines– Weak disinfectantWeak disinfectant– Potential regrowthPotential regrowth
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Limitations of DisinfectantsLimitations of Disinfectants
• OzoneOzone– Strong disinfectantStrong disinfectant– DBPsDBPs– No residualNo residual– SafetySafety– Biodegradable organics affects water Biodegradable organics affects water
qualityquality
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Limitations of DisinfectantsLimitations of Disinfectants
• Chlorine DioxideChlorine Dioxide– Strong disinfectantStrong disinfectant– DBPsDBPs– No residualNo residual– SafetySafety
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Limitations of DisinfectantsLimitations of Disinfectants
• Ultraviolet lightUltraviolet light– Not a disinfectantNot a disinfectant– No residualNo residual– Special instrumentationSpecial instrumentation– Special maintenanceSpecial maintenance
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal TechnologiesRemoval Technologies
• Conventional treatment Conventional treatment – FlocculationFlocculation– SedimentationSedimentation– FiltrationFiltration
• MonomediaMonomedia• Dual mediaDual media• Mixed mediaMixed media
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal TechnologiesRemoval Technologies
• Direct filtration Direct filtration
• Slow sand filtrationSlow sand filtration
• Diatomaceous earth filtrationDiatomaceous earth filtration
• Cartridge/Bag/Backwashable filtersCartridge/Bag/Backwashable filters
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal TechnologiesRemoval Technologies
• MicrofiltrationMicrofiltration
• UltrafiltrationUltrafiltration
• Nanofiltration Nanofiltration
• Reverse osmosis Reverse osmosis
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal Tech. LimitationsRemoval Tech. Limitations
• Conventional treatment Conventional treatment – Handle wide range of water qualityHandle wide range of water quality– ExpensiveExpensive
• Direct filtration Direct filtration – Low turbidityLow turbidity– Algae may be a problemAlgae may be a problem
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal Tech. LimitationsRemoval Tech. Limitations
• Slow sand Slow sand – Low turbidityLow turbidity– Algae may be a problemAlgae may be a problem
• Direct filtration Direct filtration – Low turbidityLow turbidity– Low removal credits for Giardia/virusesLow removal credits for Giardia/viruses– Algae may be a problemAlgae may be a problem– Not allowed in Texas on surface water Not allowed in Texas on surface water
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal Tech. LimitationsRemoval Tech. Limitations
• Diatomaceous earth filtrationDiatomaceous earth filtration– Good water quality requiredGood water quality required– Low bacteria and viruses removalLow bacteria and viruses removal
• Cartridge/Bag/Backwashable Cartridge/Bag/Backwashable – Exceptional water quality requiredExceptional water quality required– Pretreatment requiredPretreatment required– Variable particulate removal Variable particulate removal
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Removal Tech. LimitationsRemoval Tech. Limitations
• MembranesMembranes– High pressure requires exceptional water High pressure requires exceptional water
qualityquality– Stabilization of permeate requiredStabilization of permeate required– Low pressure replaces conventional Low pressure replaces conventional
treatmenttreatment– Cost is decreasing as usage increasesCost is decreasing as usage increases
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
DBP ControlDBP Control
• Move the point of disinfectant Move the point of disinfectant applicationapplication
• Increase DBP precursor removalIncrease DBP precursor removal
• Change the disinfectant usedChange the disinfectant used– PrimaryPrimary– SecondarySecondary
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
DBP ControlDBP Control
• TemperatureTemperature
• pH pH
• Aggressive flushing programAggressive flushing program
• Corrosion leads to elevated disinfectant Corrosion leads to elevated disinfectant residualsresiduals
• Supplemental (boost) disinfectant Supplemental (boost) disinfectant addition in the distribution systemaddition in the distribution system
WATER TECHNOLOGIES FOR RURAL TEXASOFFICE OF RURAL COMMUNITY AFFAIRS
Questions & AnswersQuestions & Answers