Johnson-SuBioreactorsarefairlycheapandsimpletoconstructusingreadily availablematerialsandafewbasictools.Onceyoubuiltabioreactor,itcanreused manytimeswithminormaintenance.
You’llneed:
Materials
Asheetof….guageweldmeshforthecagecolumn
A1.16mstandardwoodenpallet
8mof1.8mwideweedmat
6piecesof90mmPVCpipe
Sometiewire
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Tools
Boltcutterstocutthewiremesh.
Pliersforthetiewire
Jigsawforcuttingholesinthepallet
Drillandspaybits
Scissorstocuttheweedmat
Tapemeasure
Building the Weld Mesh Cage
Usingboltcuttersorpliers,cutthere-meshtoapprox3.6minlengthand1.50min height.Temporarilytiethewirecageendstogetherandstandthecageuplikea cylinder.
Bendtheweldmeshlengthwaysintoacolumnandsecurelytietheshortendsofthe weldmeshtogetheratnomorethan15cmintervalsusingtiewireandplierstohold ittogetherunderthepressurefromfillingitwithmaterials.
Cutting the cloth
Cuta4mlengthofweedmat.Thispieceofweedmatwillbeusedtolinetheinterior ofthere-meshcagebeforeyoufillitwithcompostingmaterials.Alsocuta1.8m lengthofweedmat,essentiallygivingyouasquaretocoverthepallet.Burnsixholes inthispieceofweedmat,positionedtoalignwiththeholesinthepallet.
Preparing the Base
ThepalletservesasthebasefortheJohnson-Su bioreactor,anditsupportsboththe weldmesh/groundclothcylinderandtheseptic systemdrainfieldpipes.Useajigsawtocutsix90mm holesinthetopofthepalletasshowninthe illustration(alternativelyuseacustomisedjigto establishtheholepositions.Exploredifferenthole placementsandseehowyoucanbestavoidcutting completelythroughthepallet’splanks,youcanpivot ajigaroundthecenterpointofthepallet.Ifyoucuta plankcompletely,placebricksorwoodenblocks underthecutendsoftheplanktosupportthemas youfillthebioreactor.
Preparing the Pipes
Usingacircularsaw,cutthesix4mlengthsofPVCpipes. Usingaspaybit,drillholesonfoursidesalongthelengthofthePVCpipes. Thepipesareonlyinplacetemporarilyandareaformtoensurethatsixcolumns areformedtoallowairflowupthroughthebioreactor.Thesepipesshouldbe removedapproximately24hoursafterfinishingthefillingofthebioreactor. Assuch,onesetofpipescanbeusedforanumberofbioreactors.
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Onceyouhaveallthesecomponentsinplaceyoucanassemblethebioreactor. Sitethepalletinaflatspotwhereyouwanttomakethecompost,andcoveritwith the1.8msquareofweedmat,lininguptheholesintheweedmatwiththeholesin thepallet.
Placetheweldmeshcolumnonthepalletandlinetheinsideofitwiththelongpiece ofweedmat,foldinganedgeoftheweedmatovertopperimeterofthecolumnto holditinplace.
Insertthepipesthroughtheholessothattheyarestandinguprightinthecolumn. Thesearetobepositionedverticallyasyoufillthebioreactor,abrace(jig)canbe usedtokeeptheminplace. Thebioreactorisnowreadyforfilling.
Furtherinstructionsonhowtomakeabioreactorandmakeandusethecompost fromabioreactorvisit:
https://www.csuchico.edu/regenerativeagriculture/_assets/documents/johnsonsu-bioreactor.pdf
Notes:
This workshop forms part of our project the ‘Lower Blackwood Online Community Forum & Information Hub’. The goal of the hub is to enhance our local farming community’s capacity to connect and engage with each other - sharing knowledge, skills and practices that build a community better prepared for, and more resilient to, the impacts of drought & other climate extremes into the future.
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