developing a cyanotoxin management plan case … a cyanotoxin management plan case study: highlands...
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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
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
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
HIGHLANDS MWC
44,000 people served via 17 water plantsSince 1969, doc cyanobacteria presence
Clear Lake
Clearlake
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
Clear Lake Treatment “50% Model”Treatment Strategies Evolve
O3
O3
O3
“TH
EN”
“NO
W”
DBPR
Highlands Treatment Plant and Intake
WTP
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
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
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)
Plan Development• Twodayson‐grounddedicatedtoeffort
• Documentedwatertreatment• Walkedthroughscenarios:triggers onwhentochangemonitoringandlocations/operations&investigations/whentonotify/whentoliftnotice,stakeholders,andpublicnotice.
• Seasonalreadyunderway• Interimplandevelopedwithbackboneofdiscussionsabove;focusedonthoseinbold
• Fine‐tuneplan:backandforthdiscussions• Bonus:Sourcewaterprotectioncomponent
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
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
Challenges, Part 3• WaterSystemisISOLATED fromwatershedactivities
• Overtheyears,moreDWtreatmentandtoolsrequired(latestwavesincludePAC,coagulantaids,filteraids,benchtopchargeanalyzers;manyalreadyhavegranularactivatedcarbon)
• Overcome:shiftfocustopartnershipstoimprovesourceWQ
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
Building Bridges in Source Water Protection• 17PublicwatersystemspooltogetherresourcestocompleterequiredCAWatershedSanitarySurvey(every5years)• Description/sourceWQmonitoring/activities/sourcesofcontaminants/changes/managementpractices/abilitytomeetSWTR/recommendationsforcorrectiveactions.
• PilotinganewWatershedSanitarySurvey!• convertingsurveyintoameanstoobtainfundingforsourcewaterprotection.Survey=fundingapplication
• Partnership:Entities/Agencies&WaterSystems
Successful Cyanotoxin Management Plan• Bepreparedtonotifycustomers
• Comfortablewiththelanguageandtriggers:arethereanylaboratory confirmationsamplesfollowingscreen?
• Carvededicatedtimeouttocompleteplan• Stepthroughthetoughscenariosandliftingthenotice• Includeareferencesamplingtableorguidefortheoperatortofollow
• Arethereanysamplingrestrictions?• Evaluatescreeningkits,includingthresholds• Planforlaboratoryturn‐aroundtime
• Getinvolvedwithsourcewaterprotection
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
Development Team• AppreciatethesupportandassistanceprovidedbytheEPA,includingHannahHolisinger
• KarenSklenarofCadmus:implementer/headofdevelopment;tirelesseffortsandabilitytoeducate,capturescenariosandabsorbinformation
• Professional,accommodating,andinformative:JeffDavis andNormBirdsey,HighlandsMWC
• AmyLittleandSheriMiller ofCASWRCBDiv.ofDrinkingWater