Anaerobic Digestion...Advantages-Challenges Anaerobic Digestion Advantage Challenges/Byproducts...

AnaerobicDigestionBiogasfromHeatusingFoodProcessingWaste/AgResidues

BioenergyAustraliaBiogasWorkshops

PresentationContent

AnaerobicandEnergy/NutrientRecoveryTechnologiesinWasteManagement

• IndustrialAnaerobicWastewaterTreatment• Anaerobicsludgedigestionandco-digestion• WastetoEnergy• NutrientRecovery

WhyAnaerobicDigestion?ApartfromtheEnvironmentalbenefits!

• Additionalrevenuefromreducingwasteorprocessingotherswastes

• Carboncreditsifitisfromasinglesourceandavoidslandfill

• Freefuelforheatandpower

• Utiliseexistinginfrastructurebyreconfiguringmunicipaldigesterstoprocessexternalstreams

AnaerobicDegradationPathwayTypeofsubstrateaffectspathwayandtreatmentprocess

+ NH4 + PO4 + H2S

OrganicWaste

Liquid

Dissolvedorganics- Brewery- PulpandPaper- Beverage

Tradewastecharges:Onsite

treatment

Tradewaste,sludgedisposal

chargesTreatment/Land

fill

Landfill Composting,various

Particulatesolids

- Slaughterhouse- Dairy- Manyfoodwastes

Solid

- Householdwaste- RestaurantWaste- GardenWaste- WAS- Slaughterhouse

Manureetc.

Slurry

Advantages-ChallengesAnaerobicDigestion

Advantage Challenges/Byproducts

Biogasproductionwith50-80%methane NH3andPO4release

0.43m3biogas/kgCOD removed H2Sproduced preferentially

0.1– 1.5m3biogas/kgVS Highlydependentonsubstrate,drives technologyselection

IndustrialAnaerobicWastewaterTreatment

Anaerobictechnologyisacceptedgloballyasthebestcarbonremovaltechnologyforconcentratedindustrialwastewaters

• BreweryandBeverage• PulpandPaper•ManyFoodindustries• DistilleryandFermentationindustry• Somechemicalindustries

AnaerobicWastewaterTreatmentSystemsAvailable

Lowrate

• VolumetricLoadingRate(kgCOD/m3.d)•AnaerobicLagoon 0.5-1•HighRateAnaerobicLagoon(HRAL) 1-2•CompletelyMixedDigesters 1-8

Mediumrate

•AnaerobicFloatationReactor(AFR) 3- 8•Upflow AnaerobicSludgeBlanket(UASB) 5-15•AnaerobicMBR 4-10

HighRate• InternalCirculationReactor(IC) 18-50

IndustrialAnaerobicWasteWaterTreatment

CUB Yatala Brewery BIOPAQ® UASB

Smiths water reuse BIOPAQ® IC + MBBR + MF + RO

Visy Paper BIOPAQ® IC + aeration + Thiopaq®

Toohey’s Brewery Biopaq® IC + MBR

Castlemaine Perkins XXXX brewery Water

reuse Biopaq® IC + Circox + MF + RO

Anaerobic MBR

Biogasutilisation

• Feedintosteamorhotwaterboilers(H2Supto2000ppmsustainableifcarefullymanaged– moreinfoprovidedincasestudy)• PowergenerationviaCHPengine• IfhighinH2S,biogaspre-treatmentrequired,evenforflaring• Siloxanesimportantformunicipal/co-digestionapplications• Typicalsitecanoffsetsiteheatingrequirementsby20-50%• Sitebiogasstoragegenerallyimpractical

HydrogenSulphidetreatment• Varioustechnologies,selectiondependentonflowrateandconcentration• Biological(Thiopaq)– GoodforextremelyhighH2Sconcentrations(1-2.5%ormore).Produceselementalsulphurcake

• Ironsponges– Goodformediumconcentrations(1,000– 10,000ppm).Regeneratedwithoxygen,mediareplacedperiodically.

• Ironoxideintroductionintodigester,combinedwithmicroaeration –Goodforlowratedigestion.Ironcontinuallyaddedtodigester

• Activatedcarbon– goodforfinalpolishingoflowconcentrations.Carbonfrequentlyreplacedatmoderateconcentrations.

Activated Carbon filterMedia Changeout

Iron SpongeMedia Changeout

Thiopaq scrubber

PowergenerationviaCHPengine• Efficiencyofapproximately40%,heatrecovery40-50%• Sulphurcontentextremelyimportantforlongtermreliability• H2Spre-treatmentusuallyviachillingthenactivatedcarbon• CHPmaintenancecosts– approximately4cperkWhr• Recoveredwasteheatutilisedinhotwaterlooptoheatdigesterorincomingfeed• Smallboosterfantoincreasepressure• Engineisalargesparkignitionengine,consumesoil

CastleHill,Sydney

Coombabah,GoldCoast

Sandgate,Brisbane

MunicipalAnaerobicCo-digestion

• DesignonVolatileSolidsloadingbasis,notCODorhydraulicretentiontime

• Organicmaterialdestruction:55-65%(solidsoutislessconcentratedthatsolidsin)

• Advantage:• Destructionoforganicmaterialwithminimalenergyrequirement

• Treatmentplantcanbeenergypositivewithadditionofexternalsubstrates

• Biogasusedforpowerandheatingofbiomass• Utiliseexistinginfrastructure(sitelocation,assetfordigestate treatment)

• Disadvantage:• AmmoniaandPhosphorusrelease(10-20%oftotalNloadinsewageplant),highernutrientloadifimportingsignificantnutrientquantities

Yarra ValleyWater,Melbourne

WastetoEnergyConcept

Manure OrganicIndustrialWaste

Biogas

ElectricityProduction

HeatHeatisaby-productoftheelectricityproduction

ElectricityTheCHPproduces

electricitywhichcanbeuseddirectlyorputinto

thegrid

GasUpgrading

FuelAfterupgradingbiogascanbeusedasCNGin

cars

GasGridThegascanbeput

directlyintogasgridandthebeusedtopowerhouseholdsorindustry

FoodWaste

WastetoEnergy

Underconstruction- YarraValleyWater,WastetoEnergyFacility– 100Tonnesperday

BiochemicalMethanePotential(BMP)Essentialtooltoevaluateprojectpotential

Alsotestthebiogasqualityanddigestate concentration!

WastetoEnergyKeyConcepts

• Revenue- Gatefees/CarbonCreditsforavoidinglandfill• Reducedrelianceongridpowerbysubstitution(FeedintariffsareminimalinAustralia)• Digestate – ideallyappliedtolandinacontrolledmannerasafertiliser.Considerrequirementforpasteurisationdependingonfinaluseandlocalbiosolids guidelines• Controlthefeed– knowhowmuchofeachsubstrateyouareadding.It’snotawastewaterplant!• Co-digestion– upgradewastereceival,feedandmixingsystemstocopewithsubstrateswithfeedconcentrationsof10-20%VS.

NutrientRecoveryTechnologiesTreatmentofliquidstreamafterdigestate dewatering

• Crystalactor®- PhosphaterecoveryasStruvite• Anammox – Lowenergyammoniaremoval

Crystalactor®• Crystallizationinfluidisedbedpelletreactor• Removalofphosphateasstruvite(Magnesiumammoniumphosphate)• Reagents– NaOH +MgCl2orMgO• pH9-10optimal• UseasMAP/DAPfertiliseralternative

LowEnergyNitrogenRemoval:Anammox®

OneStepANAMMOX®Process(InGranularSludge)

• Powerconsumptionreducedby~60%

• Noadditionalcarbonsourcerequirement

• TypicallyAverageNH4removal>90%

• CO2 emissionreducedby~90%

• Verylittleexcesssludgeproduction

• Stableandproven

• NofullscaleinAustraliaasyetbutvariouspilotsareunderway

WastewaterandWastetoEnergyProjects–

Keytakeaways

• Scaleisimportant– smallisolatedplantswithlowpowerandlandfillcostsarerarelyeconomic.Considerworkingtogetherwithotherproducersintheareatosharecostsandsavings.• Locateplantwherepowerandheatdemandsarehighwiththeabilitytoprocessdigestate• Transportcanbecostly– considersitebaseddewateringofsubstratestohighfeedconcentrationsiftransportinglongdistances• Knowwhatyourpotentialwastesourcesare– quantities,compositionandpotentialbiogasyieldtosupportbusinesscase

Futureopportunitiesandvision

• Householdfoodwaste- 4,000,000tonnesperannuminAustralia.450,000garbagetrucksperannum(www.foodwise.com.au)• Rolloutdedicatedhouseholdfoodwastebins– differenttogardenwastewhichiscurrentlycompostedorincinerated• 2weeklycollection(withheavysealedlidandodourcontrol!)• Plasticandimpuritiesareinevitable– howtoprocesseconomically?

• Processedatwastetransferstationtode-packageplastic,removebones/solidsetc.

• Tankered tonearbydigestersforenergyproduction

• Reduceduplicationofreceival/processinginfrastructure

HeatandPower

Centralisedprocessingfacilities

Howtochooseatechnologysupplierand/ordeliverypartner?

• BiogasandanaerobicdigestionindustryisrelativelysmallinAustralia.Manyclaimsandglossywebsites.• Keybackgroundchecks:

§ ABNlookup– howlonghavetheybeeninbusiness?Willtheybeinbusinessin5yearstimetosupporttheproject?Technologysupplierorjustabuilder?

§ Understandingofrelevantlegislation(ESV/QLDGasAct/NSWFairTradingetc.requirements).TypeBdevices.Hazardousareas.

§ Pastprojects,relevantlicensestooperatebusiness,builderslicence,PIinsurancesetc.

§ GoogleStreetView– dotheyhaveabusinesspremises?§ Pastprojectsandreferences§ Relevantaccreditations(ISOetc.)

ThankYou

• Pleasecomeandsayhelloafterwards!

• Anyquestions/enquiries- Digestionequipment,biogastreatment,CHP

engines,wastewatertreatment,turnkey

projects