LongTermStudyofLowCostHarvestingbyBioflocculation

MattHutton1,2;ShelleyBlackwell1;ErikZardouzian2;RuthSpierling2;Tryg Lundquist1,2

1. MicroBio Engineering,Inc.2. CaliforniaPolytechnicStateUniversity,SanLuisObispo

AlgalBiomassSummitOctober23-26,2016Phoenix,Arizona

matthutton@microbioengineering.com

Lowcostsettlingisessential• U.S.DOEEERE2014MultiYearProgramPlanupdate-

by2030:• Productionofalgae-basedbiofuelsattotalcost

of$3/GGE(2011$)• Productivityof5,000GGE/acre-year• Futureproductionof5BGYGGEperyear.

• Currentcostsprojectedat$18.63/GGE,harvestingcontributing$2.74/GGE1

1:Davis,R.,D.Fishman,E.Frank,M.Wigmosta (2012).RenewableDieselfromAlgalLipids:AnIntegratedBaselineforCost,Emissions,andResourcePotentialfromaHarmonizedModel.ReporttoUSDOEANL/ESD/12-4NREL/TP-5100-55431andPNNL-21437

• DelhiCountyWaterDistrict• 7acremunicipalracewayservingpopulation≈10,000• Nine3.5-m2 raceways,settlingunits,anddryingbeds• OperatedunderABYtooptimizeproductivityandharvesting

3

DelhiCountyWaterDistrict(ABYProject)

Southpondsusedascontrolset

• Screenedmunicipalinfluent

• Settledinpilotclarifier• 2-dayhydraulic

retentiontime(HRT)• Paddlewheelmixed

SanLuisObispoAlgaeFieldStation(ASAPProject)

• SanLuisObispoWaterResourceRecoveryFacility• Nine33-m2 raceways,settlingunits,digesters• OperatedonASAPprogramtoinvestigatewater

andnutrientreuse

• Screened,settledmunicipalinfluent

• 2-dayhydraulicretentiontime(HRT)

• Paddlewheelmixed

Gammapondsusedascontrolset

Settlingdata collectedfrombothstudies• Twosetsof2-dayHRT,municipalwastewater-fedpondsattwo

differentsites• Beakerphotostakenatbothsites• Totalsuspendedsolidsmeasuredatbothsites• Turbiditymeasuredatbothsites• CoagulantjartestsconductedatDelhi

Settleability measuredbytaking0hour,2hour,and24hourturbidityreadings(Delhi)orTSS(SLO)

Zerohoursettling

24-hoursettling

Delhi SLO2HourMeanRemovalEfficiency 78%± 14% 82%± 12%

24HourMeanRemovalEfficiency 83%± 10% 91%± 8%

Brief,intermittentupsetsdiminishaveragesettling

Withouttheseupsets,2and24hoursettlingimproveto82%and88%,respectively

24hoursofsettling

Whatcausesgoodbioflocculation?

• F/Mratio,asinactivatedsludge?

• Grazerpopulation?

• Algalorbacterialpopulation?

• Somethingelse?

Figure4.8:The2-hourTSSvsF/Mratio

Datafromallpondsets,March6,2013throughApril11,2013.Theequationoftheregressionlineisy=-132.59x+57.455,andtheR²=0.2375

F/Mratiodoesnothaveastrongcorrelationwithsettlingperformance

TwopondsetsatDelhibearthisout• Twosetsofpondsoperatedat2-dayHRTwithdifferentBODloading• Bothhadupanddown2hourbioflocculation performance• Bothaveraged74%settlingefficiency

Pond Date2-HourSettlingRemoval(%)

StandardDeviationsAboveAverage2-Hour

SettlingRemoval

SuspendedGrazerConcentration(Count/mL)Rotifers Ostracods

1 5/1/14 100% 3.0 131 2

2 6/5/14 100% 3.0 33 0

75/22/2014-

7/3/201498% 1.4 17 0

8 5/15/2014-5/29/14 92% 0.9 3 0

Pond Date2-HourSettlingRemoval(%)

StandardDeviationsBelowAverage2-Hour

SettlingRemoval

SuspendedGrazerConcentration(Count/mL)Rotifers Ostracods

1 4/24/14 65% 1.2 25 0

2 5/29/14 62% 1.5 22 1

7 7/24/14 51% 2.7 2 1

8 7/3/14 39% 3.8 0 0

Highsettling

Lowsettling

Grazerdensityshowsnocorrelationtosettlingefficiency

Reclaimedwastewater(NO3-)morepronetobioflocculating than

municipalwastewater(NH3)

15.5g/m2-dnetproductivity

16.6g/m2-dnetproductivity

Reclaimedwastewater(NO3-)morepronetobioflocculating than

municipalwastewater(NH3)

SeeKunal Poorey,ToddLane’sposter#133forinterestingresultsofgeneticsequencingoftheseponds

RelationshipbetweenpondTSSdensityandsettlingefficiency?

• Suggestsmacroscale,ororthokinetic settlingisdrivingmechanism

• Largerparticlessettlingrapidlyagglomeratewithsmallerparticles

Metcalf,Eddy,andM.EDDY."Wastewaterengineering:treatmentandResourcerecovery."McGraw-HillEducation,NewYork (2014).

• Mostlygravitysettling• Happensveryquickly• Optimaldosetoreach

10NTUatornear40mg/L

JartestsonDelhisamples

• Settlingperformanceisgenerallystrong

• Orthokinetic settlinglikelytheprimarymechanismatplay

• Brief,intermittentupsetsareoftenresponsibleforlowersettling

efficienciesovertime

• Causesofsettlingupsetsaredifficulttopredictbutpotentially

fixedwithalittlecoagulant

Conclusions

3:30Tuesday,SolanaIShelleyBlackwell,CalPolyUniversityDynamicsinAlgalProductivityandBioflocculation inWastewaterFedRacewayPonds

8:15Wednesday,SolanaHTryg Lundquist,CalPolyUniversityFromWastewatertoFuelDistillates: CultivationandProcessingofMicroalgaeGrownduringSewageTreatment

8:15Wednesday,SolanaHRuthSpierling, CalPolyUniversityEnhancedNitrogenConversionandRemovalinAlgae-basedWastewaterTreatmentSystems

LaurenParker,CalPolyUniversityPoster#264:EffectofSamplingFrequencyonMicroalgaeProductivityEstimates

Mattia Gorga,CalPolyUniversityPoster#145:Evaluationoffilamentousalgaeforanimalfeed:productivity,harvestability,andbiochemicalcompositionfromthelabandfield

Kunal Poorey,SandiaNationalLaboratoriesPoster#133:DynamicsofEcologyduringCultivationofAlgaefromWastewater

Relatedpresentations

USDOE,CaliforniaEnergyCommission

grantstoCalPolyinpartnershipwith

MicroBio Engineering,Inc.

LaurenParker,ChrisPittner,Yakov SurvovChristianBowen,ErikZardouzian,

RuthSpierling,BradenCrowe,

JohnBenemann,ShelleyBlackwell,Tryg Lundquist

Acknowledgments