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&noticeinEnglish/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

amy.little@waterboards.ca.gov