vermicomposting

VERMICOMPOSTINGBackground &

Life Cycle Analysis

Sean Brandt23 April 2001

VERMICOMPOSTING DEFINITION

Vermicomposting is the process of creating reasonably odorless compost by

red worms feeding on microorganisms that degrade organic matter such as food waste.

The worm castings (excrement) are nutrient-rich in usable forms for plants, and

therefore make excellent fertilizer.

INPUT OUTPUT

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~ ~ Vermicompost System

CLOSING THE LOOP

INPUT OUTPUT

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Vermicompost System

AGRICULTURE

microorganisms, worms

plastic

wood

VERMICOMPOSTING “SIZES”

Small – individual, homeMedium – small community or businessLarge – large community or industry

BASIC DESIGNS OF VERMICOMPOSTING

Simple boxLateral movementStackable trayContinuous flow

SMALL-SCALE VERMICOMPOSTING

Personal Responsibility

Input – personal/family food waste, some lawn and gardening wasteSystem – small bin in basement, backyardOutput – fertilizer for own gardenSustainable? – depends primarily on the bin, since “closed the loop” for some of own waste

Simple Box• Worm-A-Way (wormwoman)• 100% recycled plastic

Simple Box• Little Worm Farm Kit• Wooden


Stackable tray• Wriggly Wranch• 100% recycled plastic

Continuous flow• Earth Factory• Recycled plastic sides; steel

frame; recycled redwood lid


Lateral movement• Wormaroo


MEDIUM-SCALE VERMICOMPOSTING

(Small) Community Responsibility

Input – community/business food waste, lawn and gardening wasteSystem – large bins with different design needs than small binsOutput – fertilizer for cropsSustainable? – again, depends primarily on the bin

Continuous Flow• EPM Institutional Bin

MEDIUM-SCALE VERMICOMPOSTING

LARGE-SCALE VERMICOMPOSTING

(Large) Community Responsibility

Input – food waste, agricultural waste, paper waste, municipal solid wasteSystem – large bins; troughs; ground surface overlayOutput – fertilizer for cropsSustainable? – depends on the bin (site-specific); also transportation cost gains

GENERIC DESCRIPTION OF VERMICOMPOSTING SYSTEMSInput – food waste, lawn and garden waste, paper waste, farm animal & human excrementSystem – wooden/plastic boxes, cement troughs, direct ground overlay; microorganisms and red worms on damp beddingOutput – worm castings used as fertilizer (1/10th tonnage, 30% increased yield), “tea” (separation of liquids and solids)Sustainable? – yes, for the most part (consider consumption and disposal); gains still possible in system design

GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS

INPUT = ORGANIC MATTER

SYSTEM = CONTAINER + “NATURE”



SYSTEM: CONTAINER

Basic design considerationsSize: 1 ft3 space/lb “food” per weekTemperature: 32 ºF < T < 85 ºFVentilation/Drainage holes

Green design considerationsRecycled/Recyclable/ReusablePackaging (commercial, shipping)Source reduction: no container


SYSTEM: CONTAINERWooden Bins

reused woodno chemical sealantsnatural decomposition


SYSTEM: CONTAINERPlastic Bins

% recycled contentthermoplastic plastic vs. thermoset plasticforming processpackaging wastelasts for generations


SYSTEM: CONTAINERGround Overlay

no packaging!pile up different resources, let worms do workaesthetically pleasing if coverednatural decomposition


SYSTEM: CONTAINERCement Troughs

recycled ash (from power generation) contenttransportation, packaging of cementcrush & reuse as aggregate


SYSTEM: “NATURE”

Native worm speciesHome-grown worms“Soil foodweb”Ecosystem food chainBedding

OUTPUT = WORM CASTINGS


Summary and Conclusions

Simple, effectiveContributes to sustainability by reducing landfilling, closing loop from food chainImprovements can be made in containers and packaging (wood vs. thermoplastics vs. no container)Future – Tax on garbage, personal bins provided? Subsidy for compost? Another bin for curbside collection? Living machines?

vermicomposting

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