Groundswell -Compost Process
8
Processing City to Soil collections with the Groundswell Composting Process processing City to Soil collections with the Groundswell Composting process Composting facilities have been established in Goulburn Mulwaree Council and Lachlan Council on existing landfill sites. An on-farm composting site located in the Sydney Water Catchment for Palerang/ Queanbeyan council collections has been licensed and will be operational soon. Food scraps and garden waste collected through the City to Soil collections in Goulburn Mulwaree Council and Lachlan Council are being composted using the Groundswell’s Composting Process outlined below. The Groundswell Composting Process has been designed to meet the following criteria: require minimal new machinery or infrastructure able to use existing landfill or farm machinery (e.g. small tractor with blade or front end loader) able to operate in exposed sites with no power and minimal water minimal labour and machinery requirement simple step-by-step process that can be managed by existing waste management or farm labour without expert composting knowledge able to operate consistently with seasonally variable feed stocks able to effectively manage concerns about putrescibles including odour, vermin and birds produce the highest quality biologically active compost possible with zero physical contamination that meets agricultural market requirements. } } } } } } } } This document describes the composting process being used by four NSW councils to transform their residential food and garden waste into a high quality, high nutrient, and biologically active composted product as part of the Groundswell project. Groundswell is a three year project which is supported by the NSW Environment Trust Urban Sustainability Program. The process has subsequently been trialled and adopted by a growing number of councils and farmers to compost biosolids, cardboard, commercial pet food waste, manures, paper sludge, nappies and water weeds. Instrumental to the success of the Groundswell project has been the development of a simple but effective composting process using a bio-tech product from a Queensland company called Vital Resource Management (VRM). The bio-tech product is a two part inoculant that when properly used and managed, creates stability, predictability, consistency and no odour at any stage of the composting process. Combined with the use of compostable Biobags for the collection of food scraps, which actively dehydrate food scraps (including meat) and ensure food arrives at the composting site in an aerobic state, the entire City to Soil process is odour free from kitchen to finished product. composting process
description
Groundswell Information Sheet - Composting Process
Transcript of Groundswell -Compost Process
� ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
processing City to Soil collections with the Groundswell Composting process
CompostingfacilitieshavebeenestablishedinGoulburnMulwareeCouncilandLachlanCouncilonexistinglandfillsites.Anon-farmcompostingsitelocatedintheSydneyWaterCatchmentforPalerang/Queanbeyancouncilcollectionshasbeenlicensedandwillbeoperationalsoon.FoodscrapsandgardenwastecollectedthroughtheCitytoSoilcollectionsinGoulburnMulwareeCouncilandLachlanCouncilarebeingcompostedusingtheGroundswell’sCompostingProcessoutlinedbelow.
TheGroundswellCompostingProcesshasbeendesignedtomeetthefollowingcriteria:
requireminimalnewmachineryorinfrastructure
abletouseexistinglandfillorfarmmachinery(e.g.smalltractorwithbladeorfrontendloader)
abletooperateinexposedsiteswithnopowerandminimalwater
minimallabourandmachineryrequirement
simplestep-by-stepprocessthatcanbemanagedbyexistingwastemanagementorfarmlabourwithoutexpertcompostingknowledge
abletooperateconsistentlywithseasonallyvariablefeedstocks
abletoeffectivelymanageconcernsaboutputresciblesincludingodour,verminandbirds
producethehighestqualitybiologicallyactivecompostpossiblewithzerophysicalcontaminationthatmeetsagriculturalmarketrequirements.
}
}
}
}
}
}
}
}
This document describes the composting process being used by four NSW councils to transform their residential food and garden waste into a high quality, high nutrient, and biologically active composted product as part of the Groundswell project.
GroundswellisathreeyearprojectwhichissupportedbytheNSWEnvironmentTrustUrbanSustainabilityProgram.Theprocesshassubsequentlybeentrialledandadoptedbyagrowingnumberofcouncilsandfarmerstocompostbiosolids,cardboard,commercialpetfoodwaste,manures,papersludge,nappiesandwaterweeds.
InstrumentaltothesuccessoftheGroundswellprojecthasbeenthedevelopmentofasimplebuteffectivecompostingprocessusingabio-techproductfromaQueenslandcompanycalledVitalResourceManagement(VRM).Thebio-techproductisatwopartinoculantthatwhenproperlyusedandmanaged,createsstability,predictability,consistencyandnoodouratanystageofthecompostingprocess.CombinedwiththeuseofcompostableBiobagsforthecollectionoffoodscraps,whichactivelydehydratefoodscraps(includingmeat)andensurefoodarrivesatthecompostingsiteinanaerobicstate,theentireCitytoSoilprocessisodourfreefromkitchentofinishedproduct.
c o m p o s t i n g p r o c e s s
� ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
Summary of Composting ProcessTheCitytoSoilfeedstockofcombinedkitchenandgardenwastecreatessomespecialopportunitiesandrisksforsuccessfulcomposting.Thehighernutrientandmoisturelevelspresentinthefoodscraps,combinedwithpotentiallychallengingingredientssuchasmeatscrapsprovidesaperfectfeedstocktoproduceamicrobiallyrich,highnutrientproductifcorrectlyprocessed.ThespecificsoftheVRMactivatedcompostingprocess(technicallymoreofafermentativeprocess)areoutlinedbelow.Inessence,thecompostingprocesshasbeendevelopedforsimplicity,cost-effectivenessandefficiencywhileensuringapremiumcompostproduct.
Thecompostingprocessisattractingsignificantinterestduetoitslowlabour,plantandwaterrequirements.Thekerbsidecollectedfoodscrapandgardenwastefeedstockisnotshreddedpriortoprocessing.Thisremovestherequirementforshreddingequipmentonsite.Additionally,thefermentativeprocessreducesthenumberofturnstojustonceduringthe8-��weekcompostingprocess.Thisresultsinacheaper,cleanerendproductwithlessphysicalcontamination.
Theprojectisalsochallengingassumptionsthattheprocessingoffoodissynonymouswithverminandodourissuesandneedstooccurindoorsorinvessel.
FeedstockTheCitytoSoilfeedstockincludessourceseparatedhouseholdkitchenandgardenwaste.Allfoodscrapsincludingmeat,bones,dairyproductsandfatareincluded.
Householdersinparticipatingtownshavereceivedvented6litreMaxAirkitchenbench-topfoodscrapbinsandayear’ssupplyofcompostablebiobags.ThebiobagsandMaxAirbinsminimiseodoursbyallowingthecontentstobreathe.Whenthebiobagsarefull,theyaretiedclosedandplacedintheCitytoSoil�40Lwheeliebin(MGB)alongwithanygardenwaste.
InGoulburnMulwareethe�40litreMGBsarecollectedmonthly.InCondobolin,thecollectionisfortnightly.
� ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
stage 1: picking
Feedstockisdelivereddirectlyontothecompostingsite/hardstandarea.Wherepossiblethetruckshouldspreadthematerialoutoverawideareatofacilitatepickingandspraying.Thematerialarrivespre-mixedwithfoodscrapsneatlycontainedinBiobagswhicharestillintactbutvisiblydehydrated.Thereisusuallynoodouratpointofdelivery.Occasionallyandseasonally,theremaybesometemporaryodoursduetolawnclippingswhichmayhaveslumpedinthebaseofMGBsandturnedanaerobic.Thisseemstochangequitequicklyonceonsite.Ifodourisnoticeableorunacceptableatthisearlystage,thematerialcanbesprayedwithdilutedinoculantspriortopicking.
Thefirsttaskinthecompostingprocessistopickthroughthefeedstockbyhandtoremoveanyphysicalcontamination.Anicefeatureofthebiobagsisthattheyensurethefoodscrapsarriveattheprocessingsitesomewhatdehydrated,neatlycontainedandinanaerobicstatewithnoodour.Evenwithamonthlycollectionthebagsarerobustenoughtoremainintactduringthecollectionandcompactionprocess.
Typicalcontaminationremovedatthisstageincludesthebottles,cansorplasticbags.Thebiobagsoffoodscrapsgointothecompostingprocessintact.
Onceanyphysicalcontaminationisremoved,thefeedstockissprayedwiththeVRMPhotonCompostingsolutionsandanappropriateamountofnonorde-chlorinatedwater.
4 ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
stage 2: inoculating
ThecompostinginoculantisacombinationofVRMPhotonStarterCulture®andVRMPhotonSeedingAgent®.TheVRMPhotonStarterCultureandVRMPhotonSeedingAgenthasbeenspecificallyselectedtomeetthefeedstockrequirementsofacombinedfoodandgardenwastecollection.
Dilutionratesare�litreofstartercultureand�litreofseedingagentdilutedinaminimumof�0litresofwaterforevery�0cubicmetersofgreenwaste.(i.e.,�00mlsofeachproductforeachcubicmeteroffeedstock)
Bothproductsshouldbedilutedinwaterattheaboveratespriortoapplication.Ideallythecompostingsolutionshouldbeappliedunderpressureusingafullconesprayoratomiser(e.g.ayellowpressurenozzle)asexposureofthesolutiontooxygenkick-startstheoxidisationprocesswhichkick-startsbiologicalactivitywhilethefinedropletsizemaximisessurfacecoverage
Thepilesshouldbequitewetbeforecovering(ideally40%–60%,min�0%moisturetomax80%moisture)-wetterthanwouldnormallybeassociatedwithopenwindrowcomposting.Ifextrawaterneedstobeaddedtothepilesthedilutionratecanbeincreasedbyincreasingtheamountofwatertheinoculantsaremixedwith.Inpractice,acombinedfoodscrapandgardenwastecollectionisreasonablymoistandshouldonlyrequireasmallamountofadditionalwater.(Forexample,inGoulburnMulwareeCouncil,�000litresisusuallyaddedtoeach�00tonnebatchoffoodscrapsandgardenwaste,regardlessofseasonalvariation,InCondobolin,wheretheclimateisdryer,approximately�50-�00litresofwaterisappliedtoeach�0tonnebatchoffeedstock).
Oncethepilesarewetandinoculatedtheyarepiledintowindrowsandfullycoveredwithdurable,waterproofpolytarpsweigheddownwithtyresorotherheavyobjectsthatwillnotdamagethetarps.Toassistwithwaterreticulationthroughthepile,windrowsshouldhavean‘M’profileandsmallerpilesshouldhaveaflattopandasmalldiporhollowinthemiddle.Thisassistscondensationtodripbackintothepile.Highinternaltemperaturesdrivemoisturetotheoutsideofthepileandstepsshouldbetakentoensurecondensationontheinnersurfaceofthetarpdoesnotdripdownthesidesandoutofthepile.Goodcontactbetweenthetarpandthepilehelps.Morerecentlyon
largersiteswehavestartedusingtarpswithahemreinforcedwith��/�”waterpipeandeitherclampsorsandbagstokeepthetarpstightandtocounteractstrongwinds.
Broadlyspeakingtheinoculantcontainscombinationsofaerobicandanaerobicbacteria,specialfungiandyeasts.Thecompostingprocessismoreaccuratelydescribedasafermentativeprocess.Specificmicrobesareincludedthatactivelybreakdownfats,meatsandotherdifficultproductsthatmightchallengeaconventionalaerobiccompostingprocess.Withincertainlimits,thespecificbalanceofcarbontonitrogeninthefeedstockisnotvitaltothecompostingprocessbecausetheinoculantscontainbothcarbonfixingandnitrogenfixingbacteria.
5 ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
Odourproducedbysulphurreducingbacteriawhichpredominateinconventionalanaerobicprocessesisaddressedbytheinclusionofphotosyntheticbacteriaandpurplenon-sulphurbacteriaintheinoculantmix.Thesebacteriaconsumethesulphurreducingbacteriaandalsocompetefortheirfoodsource.Thepurplenon-sulphurbacteriarequireanaerobicconditionstoflourishandoutcompetethesulphurreducingbacteria.Unlikethesulphurreducingbacteria,thepurplenonsulphurbacteriaareinhibitedbysunlight.Coveringthepileshelpstocreatetheconditionsforthepurplenon-sulphurbacteriatoflourish.
Collectivelythesecompostingsolutionsprovidearangeofsignificantadvantages.
therequirementtoturnpilesisreducedasthemicrobialpopulationdoesnotrequireventilation.
carbonretentionisconsiderablyhigherthaninregularcomposting.
odourisgreatlyreducedandinmostinstanceseliminatedalltogether.Wehavefoundthatthereisnoissuewithodouratanystageofthecompostingprocess.
therequirementtocoverpileswithpolytarpssignificantlyincreasesthethermalandmoistureefficiencyofthepiles,reducingbothwaterrequirementsandrunoff.
AdditionalinformationonVRMcanbefoundat:www.vrm.com.au
Thecoveredpilesareleftforfourtosixweeks.Duringthefirstdayortwothetemperatureclimbstoaround65-70°Casaflushofaerobicactivitytakeplace.Bytheendofthefirstweekthetemperaturestabilisesataround50-55°C.Thisearlyaerobicflushofactivityprovidesthefirstoftwoopportunitiesforpasteurisation.Ifwellmanaged,thesetemperaturesareevenachievedontheoutsideofthepiles.AccordingtotheAS4454standards,compostmustreachandholdatemperatureof55°Cforthreedaystoachievepasteurisationrequirements.Iftheexpectedtemperaturesareachievedthroughoutthepile,theGroundswellcompostingprocessexceedsthepasteurisationrequirementsoutlinedinthestandard.
Inassociationwiththestabilisationoftemperaturearound55°C,thepHleveldropstoaround�.5-4.5asthefermentativebacteriacolonisethepiles.Thepilesshouldremainquitewet,andthecolourquickly
}
}
}
}
changestoauniformblackcolour.Additionally,rayfungiandactinomycesquicklystarttoinfiltratethepilesandcanbeobservedasgreyfilamentsorpowderyflakes.Ifthesegreypowderyflakesandfilamentsarepredominating,itcanbeanindicationthatthepileistoodry,socheckmoisturelevelsandapplyde-chlorinatedornon-chlorinatedwaterasrequired.
Evidenceofsecondarycompostingprocessescanusuallybeobservedontheoutersurfaceofthepileswherethereismoreoxygenandthetemperatureiscoolerthroughthepresenceofslaters,nativecockroachesandotherlargersoilbiology.
Moisturelevelsduringthefermentationprocessshouldfallnolowerthan�0%withanoptimummoisturelevelof40%-60%butnohigherthan80%whereadequateleachatecontrolsareinplace.Ideally,thesurfaceofthepile(underthetarps)shouldremainmoist.
6 ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
stage 3: turning and respraying
After4-6weeks,thepilesareuncovered,spreadandre-examinedtoremoveanyphysicalcontaminationthatmighthavebeenmissedatthebeginningoftheprocess.BythisstagethepileshaveslumpedbyaboutathirdandtheBiobags,foodscrapsandsmalleritemshavedisappeared.Smallerpiecesofcontamination,aswellasthosethatmayhavebeenenclosedintheBiobagsbecomeeasiertoseeasthecomposthastakenonauniformtextureanddarkcolour.
Thecompostisthenmixed,re-wet,resprayedwiththeinoculants,re-piled,recoveredandleftforanother4to6weekperiod.Asimilarearlyspikeintemperature(around65-70°C)followedbyalongerperiodataround50-55°CandanassociatedpHlevelof�.5-4.5canbeexpectedduringthesecondfermentationstage.Thisprovidesthesecondopportunityforpasteurisationandensuresmaterialthatwaspreviouslyontheoutsideofthepilehasbeenre-incorporatedandprocessed.
stage 4: maturation & storage
After8-��weeks,dependingonprocesscontrolandparticlesizeoftheoriginalfeedstock,temperaturesshouldslowlycomedownandpHshouldreturntoneutral.Thecompostcanbelefttomature.Pilesshouldbekeptcoveredandnotallowedtodryout.Ideally,pilesshouldnotdropbelow40%moisture.
Theendproductispredominantly‘chocolatebrownie’innaturewithsomelonger,coarser,butsignificantlysoftenedparticulate.Itisusuallytoofineorsofttoputthroughashredderorgrinderbutissuitableforascreening(e.g.flipscreen)process.Arotatingdrumtrommelwitha�6mmmeshresultsinanexcellentfinishedproduct.Largerparticlesthatarescreenedfromthecompostcaneitherbereprocessedintothenextcompostbatchorstockpileduntilashredderorgrinderbecomesavailable.
Anylastremainingphysicalcontaminantsshouldberemovedpriortoscreeningorfinalprocessing.Tofacilitatestabilisation,pilescanbescreenedandlefttomature.
Undercorrectstorageconditions,thelongerthepilesarelefttomature,thebetterthecompostbecomes.WehaveobservedtheCationExchangeCapacityoffinishedcompostincreasefrommid�0sto7�afterstorageforseveralmonths.
7 ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
About the MaxAir IITM bins and BiobagsTM
TheGroundswellprojectutilisedtheMaxAirIIsystemwhichcombinesa6litreventedplasticbucketandrollsof�0litrecompostablebags.ThecombinedMaxAirbucketandbagsaredesignedtopreventodoursandputrificationoffoodwastebyretainingfoodscrapsinanaerobicstate.Thebreathabilityofthebagsandbucketpromotesventilationandevaporationofmoisture,resultinginaweightreductionofupto�5%infivedaysand40%insevendays.Initialtrials,researchandmarkettestingindicatehighlevelsofhouseholderacceptanceoftheproduct.TheMaxAirbinsandBioBagsarecurrentlyusedinover�00municipalitiesglobally.
TrialsundertakenbytheGroundswellProjectTeaminearly�008testedtheperformanceoftheMaxAirBinsandBiobagsinamonthlycollectionscenario.Inthistrial,compostablebagswerefilledwitharangeof‘highrisk’foodscrapsincludingfishcarcasses,meat,left-oversandrottenfruitandvegetables.Bagswerethenplacedinanumberof�40litreMGBswithvaryingamountsofgardenwaste.Binsweremonitoredovera4weekperiod.Atnostageduringthetrialwereoffensiveodoursdetectedinsideoremanatingfromthebins.Thecompostablebagsappeartoassistgreatlyinkeepingfoodscrapsaerobic.OdourswereconsiderablylessthanmightbeexpectedfromputrefyingfoodwasteenclosedinplasticbagsinresidualwasteMGBs.
TheBioBaghasaveryhighpenetrationbarrieragainstbacteria,viruses,sporesandmould.BioBagsalsoensuresaferandmorehygienicconditionsforwastecollectorsandcompostingfacilities.BioBagsarefullycompostableandcertifiedaccordingtotheEuropean
StandardEN��4��andtheUSstandardASTMD6400,whichiscompatiblewith
theAustralianStandardAS4454.
VRM Inoculants and Odour ManagementCompostingisgenerallyunderstoodaseitheranaerobicoranaerobicprocess.OneoftheremarkablecharacteristicsoftheVRMPhotonCompostinginoculantsusedintheGroundswellCompostingProcessisthelackofodourproducedeventhoughitisessentiallyatwophasestaticpilesystem.Inovertwoyearsofcontinuousprocessingofcombinedfoodscrapsandgardenwaste,thecompostingsitesatGoulburnandCondobolinhaveneverproducedanodourproblemoranynoticeableodour.Thissituationhasbeenreplicatedatmorethansevenothercouncilsiteswithevenmorehigh-riskmaterialsincludingbiosolidsandcommercialfoodwaste.TheGroundswellCompostingProcessrecruitsmicrobiologythatarebothaerobicoranaerobicorboth.
TheVRMInoculantsincludeEffectiveMicroorganisms(EM)whichareusedaroundtheworldtotreatsewerage,wastewater,foodwaste,municipalwaste,andimprovingorrehabilitatingagriculturalsoil.TogetherwitharangeofotherformulationsallculturedinAustralia,VRMInoculantsincludeseedpopulationsofpurplenonsulphurbacteriaandotherphotosyntheticorganisms.TheVRMinoculantsalsocontainfamiliesoffungi,(egactinomyces),yeasts,andotheraerobicandfermentingbacteria(e.g.lactobacillus,cyanobacterandrayfungi).ThekeyfamiliesofbacteriaresponsibleforthemanagementofodourintheGroundswellCompostingProcessarephotosyntheticbacteriaingeneralandpurplenonsulphurbacteriainparticular.
8 ProcessingCitytoSoilcollectionswiththeGroundswellCompostingProcess
thepile.Purple-non-sulphurbacteriadirectlycompetewithsulphurreducingbacteriaforsulphate,donotproducesulphidecompoundsandcanbeculturedinthecompostingpilewithoutdifficulty.
Theresultisacomplexinterdependencyofbiologicalfamilieswhicheachcreatetheconditionsforthe
othersandprotectagainstthedominantbiologicalprocessinthepilebecomingputrefactiveorodorous.Theprocessisperhapsmoreeasilyunderstoodasakintoasilageprocess.
TheGroundswellCompostingProcessisattractingsignificantinterestfromothercouncilsandprocessors.Tohelpbuildtheknowledgebaseaboutthisnewapproachtocomposting,theNSWDECCWhascontractedanodourstudytoascertainexactlywhatemissionscomeoffthepiles.Theresultfromthisstudywillbeavailableinearly�0��.
For updates and more information on the Groundswell project go to: www.groundswellproject.blogspot.com
Written by Simone Dilkara, 2010. Graphic design/illustration by Carolyn Brooks
This work is licensed under the Creative Commons Attribution 3.0 Unported License and can be reproduced providing the Groundswell project is acknowledged as the original source.
The Groundswell Project was assisted by the NSW Government through its Environmental Trust
Thephotosyntheticbacteria(whichperformphotosynthesisanaerobically)areintegraltotheGroundswellCompostingProcessbecausetheysupportprocesseswhichtransformputrefactivesubstancessuchahydrogensulphideintousefulorbenigncompoundssuchasoxygen,water,hydrogenperoxideorcarbondioxide.Intherightconditions,somephotosyntheticbacteriausetheheat(ratherthansunlight)generatedinthepileasenergyandhydrogenfromhydrogensulphide,methanegas,indol,skatole,methylmercaptansandotherorganicacidsandcompoundsproducedduringthedecompositionoforganicsubstances.Creatingtheconditionsforphotosyntheticbacteriatoflourishduringcompostingsimultaneouslybreaksdownodourproducingcompoundssuchashydrogensulphide,out-competessulphurreducingbacteriaandgeneratesoxygenwithin
