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Developing a Cyanotoxin Management Plan Case Study: Highlands MWC
USEPA supported effort
Jeff Davis (General Manager) and Norm Birdsey (WQ Manager/Operator)EPA/CA-SWAMP @ SCCWRP Workshop, April 25-27, 2017
Presented by Amy Little, CA SWRCB- Division of Drinking Water
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Why develop a plan in Clear Lake? • 17watertreatmentplantsaroundClearLake,CA:developingonecouldserveasatemplateforothers
• UCDavisresearch(1969‐1991):IDcyanobacteriaand• cellconcentrationsexceedWHOrecreationvalues• Thickalgalmats,neurologicaldisordersreportedincatsfollowingabloomeventin1989
• Snapshot ofmicrocystin monitoringatdrinkingwaterintakesin2011(max8ug/L),2013(2.4ug/L)and2014(2.4ug/L)demonstratesEPAHealthAdvisoryof0.3ug/Lisexceededinrawwater(andWHODWlevel,1ug/L)
• Recreationalmonitoring:2010and2011County/SWAMPmonitoring,ongoing(BigValleyRancheriaBandofPomoIndiansandElemColony)– totalmicrocystins exceeding10,000ug/Lattheshoreline.
• Q:Ismywatersafetodrink?Customersareinquiring
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Cyanotoxin Monitoring Plan Highlights• Step1.AssessSourceWater:EPADWMAPStool• Step2.Monitorforearlywarningsigns
• Sludgeturnsgreen,dielpHswings(7.7to9.7)• Step3.RawWaterMonitoringandTreatmentAdjustments
• Treatmentadjustment: seasonalPACoperations+• Step4.FinishWaterMonitoring/TreatmentAdjustments/PublicCommunication• Hemodialysiscenters¬iceinEnglish/Spanish• UsingMCADDA‐specificELISAfordecisionmaking• Focusedon0.3ug/LfortotalMCforPN
• Step5.ContinuedFinishedWaterCyanotoxinMonitoring/TreatmentAdjustments/PublicCommunication:Totalcoliformandtanksitesused
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HIGHLANDS MWC
44,000 people served via 17 water plantsSince 1969, doc cyanobacteria presence
Clear Lake
Clearlake
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Cyanobacteria Water Treatment challenges• SourceWaterQuality
• Diel pHfluctuationscanbeextreme(acidadditionstocounter)
• Elevatedtotalorganiccarbon(attimes>10ug/L)• SuiteofTreatmentIssues:
• Shortfilterruns/Cloggedfilters• Increasedpre‐oxidationdemand• Increasedcoagulantdemands• Increasedfilterbackwashing/clarifiersludgeremoval• Increaseindisinfectionapplicationstomaintainrequiredresiduals
• Incr.disinfectionbyproductformation– installedaerationsys
• Taste&Odorcomplaints– largelyresolved• Unknownimpactsfromcyanotoxins
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Clear Lake Treatment “50% Model”Treatment Strategies Evolve
O3
O3
O3
“TH
EN”
“NO
W”
DBPR
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Highlands Treatment Plant and Intake
WTP
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Highlands Mutual Water Company• ServingaportionofClearlake,CA,poorestcountyinthestate
• Connections:2,876 Populationserved:6,170• Supplyahemodialysiscenter– improvedcommunicationin2011
• Conventional coag +floc+sedimentation+filtration• Conventionaltreatmentplantwithadditionaltreatment
• In2015,operatingat1.4MGD(1,000gpm)• Pre‐treatment:pre‐oxidants(ozoneandsodiumhypochlorite),PAC• Processtreatment:filteraid,coagulantaid• Post‐treatment:twotypesofGAC
• Technicalexchangepartners
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OZONE-2
OZONE-1
150 HP GAC
GAC
PRESSURE FILTER -2
PRESSURE FILTER -1
CLARIFIER-1
CLEARWELL 397 K
150 HP
1.7 MGD max
720 GPM max
480 GPM max
CLARIFIER-2
KMNO4 NaOCl
PAC
ACH
NaOCl
Zn3(PO4)2
Screw press
Recycled Water to Headworks Sludge
Highlands MWC Treatment Plant
Filter aid
To customers
Microcystin monitoring point
Coag aid
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Highlands MWC Treatment Plant cont…• FilterBackwashingofOneMulti‐mediaPressureFilter:
• Design:backwashafilterevery1to4days*• 80%ofthetime: 1filterbackwash/day• 10%ofthetime: 2filterbackwash/day• 10%ofthetime: 3+filterbackwash/day• Createsneedforbackwashdisposal
• EmptyBedContactTimeinCarbonFilter:• Design:cyanotoxinreferencesindicateminimumof10minutes• HighlandsMWC:30minutes• AnotherconventionalplantonClearLake:38minutes
*WaterTreatmentPrinciplesandDesign,2nd edition,MWH(2005)
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Plan Development• Twodayson‐grounddedicatedtoeffort
• Documentedwatertreatment• Walkedthroughscenarios:triggers onwhentochangemonitoringandlocations/operations&investigations/whentonotify/whentoliftnotice,stakeholders,andpublicnotice.
• Seasonalreadyunderway• Interimplandevelopedwithbackboneofdiscussionsabove;focusedonthoseinbold
• Fine‐tuneplan:backandforthdiscussions• Bonus:Sourcewaterprotectioncomponent
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Challenges, Part 1• MonitoringFrequency/SamplingSchedule
• Questionswrestledwith:(1)howbesttocapturepeakinrawmonitoring,(2)partnershiprestrictedscheduletobi‐weekly,(3)ifraw>0.3ug/LMC,howdowecollectfinishsample?
• Overcome:collectedfinishwatersamplesatsametimeasraw• Publicwatersystemshavemanycompetingprioritiesandwearmultiplehats:managersandoperators• Attimeofdevelopment,
• Backwashprojectindevelopment• Granularactivatedcarbonmediafilterchange• Day‐to‐dayoperations:5operatorsonstaff,turnovercanbeaproblem
• Overcome:scheduletime/meetingstoaccomplishtasks
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Challenges, Part 2• LaboratoryMethod:whichtouse?
• Interferences,turn‐aroundtime,partialMCvs.ADDAspecific
• Overcome:Introducedflexibility tousetheADDAspecificELISAwithanoptiontouseEPAMethod544forconfirmation
• Nowthere’sEPAMethod546,anotherconsideration• Knowingwhentoliftthenotice
• Doweflushthesystem/tanks?Whatamountofsamplingensuresitissafetodrink?
• Overcome: usedroutinebacteriologicalmonitoringsitesandstoragetanksites.• 1st :striptest 2nd :confirmwithlaboratoryorADDA‐specificELISA
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Challenges, Part 3• WaterSystemisISOLATED fromwatershedactivities
• Overtheyears,moreDWtreatmentandtoolsrequired(latestwavesincludePAC,coagulantaids,filteraids,benchtopchargeanalyzers;manyalreadyhavegranularactivatedcarbon)
• Overcome:shiftfocustopartnershipstoimprovesourceWQ
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Source water protection = education• HABsriskfactorscanberanked:vulnerableApril‐ Nov• Readthewatershedreports
• Impairedwaterbodyfornutrients(andmercury)• TMDLdevelopedinresponse– target:phosphorus,derivedfromsedimenterosion
• UseTools:USEPADWMAPS – identifypotentialsourcesofcontaminationinwatershed(tier1‐watershedboundaryzoneandtier2– 10mi.upstreamzone)• PointsourcesofP(andN)canbeidentified(2%)• Non‐pointsourcesofPcarrytheload(98%)
• ActivitiesID’d mostlikelytobesourceofexcessP
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Building Bridges in Source Water Protection• 17PublicwatersystemspooltogetherresourcestocompleterequiredCAWatershedSanitarySurvey(every5years)• Description/sourceWQmonitoring/activities/sourcesofcontaminants/changes/managementpractices/abilitytomeetSWTR/recommendationsforcorrectiveactions.
• PilotinganewWatershedSanitarySurvey!• convertingsurveyintoameanstoobtainfundingforsourcewaterprotection.Survey=fundingapplication
• Partnership:Entities/Agencies&WaterSystems
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Successful Cyanotoxin Management Plan• Bepreparedtonotifycustomers
• Comfortablewiththelanguageandtriggers:arethereanylaboratory confirmationsamplesfollowingscreen?
• Carvededicatedtimeouttocompleteplan• Stepthroughthetoughscenariosandliftingthenotice• Includeareferencesamplingtableorguidefortheoperatortofollow
• Arethereanysamplingrestrictions?• Evaluatescreeningkits,includingthresholds• Planforlaboratoryturn‐aroundtime
• Getinvolvedwithsourcewaterprotection
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2016 Update and Next Steps• Eightadditionalwatersystemsadoptedtheabbreviatedplanin2016andparticipatedinthesomeformofmonitoring
• 2016rangeofconcentrationsattheintake:ND– 0.73ug/L• infinishwater:ND– 0.18ug/L• NextSteps:
• Continuequarterlywatersystemmeetings;startedin2016• Hosttwo‐dayjartestworkshopwithbenchtopchargeanalyzertooltooptimizecoagulantdosages(lastweek)
• Participatein2017WatershedSanitarySurvey• Use0.45umfiltersonrawwatertopotentiallydriveozoneoperations(toexamine[intra‐,extra‐cellular]distributionofMC),+sludge
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Development Team• AppreciatethesupportandassistanceprovidedbytheEPA,includingHannahHolisinger
• KarenSklenarofCadmus:implementer/headofdevelopment;tirelesseffortsandabilitytoeducate,capturescenariosandabsorbinformation
• Professional,accommodating,andinformative:JeffDavis andNormBirdsey,HighlandsMWC
• AmyLittleandSheriMiller ofCASWRCBDiv.ofDrinkingWater
[email protected]