1. Background & Life Cycle Analysis
VERMICOMPOSTING
Background &
Life Cycle Analysis
Sean Brandt
23 April 2001
Motivation from personal considerations (MB’s backyard bin; my own) & check for application of Green Design fundamentals

2. 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.
Why do it? Contributes not only to water conservation, energy conservation, and soil preservation, but brings the user closer to a zero waste goal – SUSTAINABLE. ~
Vermicompost System
INPUT
OUTPUT

3. CLOSING THE LOOP ~ microorganisms, worms plastic wood INPUT OUTPUT
Vermicompost System
Actual considerations vary by size; “WASTE” as not having immediate use for human consumption (gardening at MEZ, interview with Dai-En Roshi, quoting Thoerau); Market is actually large and growing throughout the world (US vs. 2nd, 3rd world); No “universal” system applicable, depends on locale – from the size to the native worms, to the design considerations for climate.
AGRICULTURE

4. VERMICOMPOSTING “SIZES”
Small – individual, home
Medium – small community or business
Large – large community or industry
Small – my personal interest; Medium – rural areas, small companies, developing countries; Large – primarily developing countries, possible future work in US as part of Living Machines.

5. BASIC DESIGNS OF VERMICOMPOSTING
Simple box
Lateral movement
Stackable tray
Continuous flow
Simple box – most common. Lateral movement – works well, small-scale only, one of initial designs in 1970s.
Stackable tray – what CCSWA has; some problems. Continuous flow – probably best option, especially as scale increases.
Now: consider different sizes, then generalize for sake of time.

6. SMALL-SCALE VERMICOMPOSTING Personal Responsibility
Input – personal/family food waste, some lawn and gardening waste
System – small bin in basement, backyard
Output – fertilizer for own garden
Sustainable? – depends primarily on the bin, since “closed the loop” for some of own waste

7. SMALL-SCALE VERMICOMPOSTING
Simple Box
Worm-A-Way (wormwoman)
100% recycled plastic
Simple box: most common, filled ¾ with bedding, harvest compost 3-6 mos., anaerobic stench unless adequately ventilated.
Simple Box
Little Worm Farm Kit
Wooden

8. SMALL-SCALE VERMICOMPOSTING
Stackable tray
Wriggly Wranch
100% recycled plastic
Stackable tray: multiple trays with screens as bottoms, above a liquid collection tray; minimize hand-sorting of vermicompost; worms may get stranded in a layer if new tray added too early, some worms drown.
Continuous flow: food added gradually, vermicompost taken from the bottom. Worms move upward.
Continuous flow
Earth Factory
Recycled plastic sides; steel frame; recycled redwood lid

9. SMALL-SCALE VERMICOMPOSTING
Lateral movement
Wormaroo
Lateral movement: common initial home-made bin design, from 1970s. Worms feast on one side of a divider, then divider is removed to a fresh food source, and after several weeks, they have all migrated. The divider is reintroduced and the vermicompost is harvested. Very efficient.

10. MEDIUM-SCALE VERMICOMPOSTING (Small) Community Responsibility
Input – community/business food waste, lawn and gardening waste
System – large bins with different design needs than small bins
Output – fertilizer for crops
Sustainable? – again, depends primarily on the bin

11. MEDIUM-SCALE VERMICOMPOSTING
Continuous Flow
EPM Institutional Bin
Continuous flow dominates because of savings in time and labor increase. Also, larger-scale vermicomposting has to address heat decomposition because of the solar gain, since the larger mass retains heat better. Temperatures have been observed up to 145 ºF! This can affect the livelihood and performance of bacteria.
The bin has been used at a prison with great success, including $76,000 savings in disposal costs avoided.

12. LARGE-SCALE VERMICOMPOSTING (Large) Community Responsibility
Input – food waste, agricultural waste, paper waste, municipal solid waste
System – large bins; troughs; ground surface overlay
Output – fertilizer for crops
Sustainable? – depends on the bin (site-specific); also transportation cost gains
Example: Bombay, India used a vermicomposting system to help treat MSW, but dumping was cheaper than value of fertilizer.

13. GENERIC DESCRIPTION OF VERMICOMPOSTING SYSTEMS
Input – food waste, lawn and garden waste, paper waste, farm animal & human excrement
System – wooden/plastic boxes, cement troughs, direct ground overlay; microorganisms and red worms on damp bedding
Output – 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
Now: consider vermicomposting and green design thereof, in general terms regardless of size.
Actual considerations vary by size; “WASTE” as not having immediate use for human consumption (gardening at MEZ, interview with Dai-En Roshi, quoting Thoerau); Market is actually large and growing throughout the world (US vs. 2nd, 3rd world); No “universal” system applicable, depends on locale – from the size to the native worms, to the design considerations for climate; Microorganisms=fungi(wood-based waste), bacteria(green waste) that degrade organic matter; Protozoa and Nematoades eat them; Worms eat them; Crop yields increase between 10% and 40% (castings alone or worms and castings)

14. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
INPUT = ORGANIC MATTER
Organic matter as a by-product of human consumption is of interest. Mostly vegetable matter is best as “food”; coffee grinds, egg shells work well. Paper, egg-shell cartons, and teabags work OK. Animal products are undesirable from the underlying chemical mechanisms of the system; bones and cartilage take a long time to decompose and rotting meat smells.

15. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM = CONTAINER + “NATURE”
Is the container “green”? Is the “nature” of the ecosystem within natural, sustainable?

16. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: CONTAINER
Basic design considerations
Size: 1 ft3 space/lb “food” per week
Temperature: 32 ºF < T < 85 ºF
Ventilation/Drainage holes
Green design considerations
Recycled/Recyclable/Reusable
Packaging (commercial, shipping)
Source reduction: no container
Ventilation holes – worms stay where best food source is; allows for oxygenation so small population of anaerobic = stinky bacteria. Drainage = “tea”.

17. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: CONTAINER
Wooden Bins
reused wood
no chemical sealants
natural decomposition
Typically homemade. Reused wood: old furniture, leftovers from other home-improvement projects; Chemicals: change output leachate – fertilizer, groundwater supplies; Natural Decomposition: within a human lifetime, microorganisms

18. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: CONTAINER
Plastic Bins
% recycled content
thermoplastic plastic vs. thermoset plastic
forming process
packaging waste
lasts for generations
% Recycled Content – varies by actual bin, ideal is 100%; e.g., not advertised; Thermoplastic vs. Thermoset – former can be remelted, latter cannot, so prefer former because easier to recycled in LR; Forming Process – blow or extrusion molding, more likely latter because of sizes considered (good because trimming waste can be reused for thermoplastics); Packaging Waste – Not much packaging for these large containers (not prone to theft, have stickers for advertising); waste comes from shipping, so need to ship as “greenly” as possible; Lasts for Generations – e.g., #5 plastic = PP=polypropelene (not PET, HDPE, PE, LDPE) not taken by CCSWA

19. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: CONTAINER
Ground Overlay
no packaging!
pile up different resources, let worms do work
aesthetically pleasing if covered
natural decomposition
As green as it gets. In LR, leaves no trace.

20. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: CONTAINER
Cement Troughs
recycled ash (from power generation) content
transportation, packaging of cement
crush & reuse as aggregate
Sometimes necessary for medium- and large-scale jobs; better than land-filling alternative. End-of-line – aggregate not as strong.

21. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
SYSTEM: “NATURE”
Native worm species
Home-grown worms
“Soil foodweb”
Ecosystem food chain
Bedding
Native worm species – red worms in all soils, so maintain ecosystem integrity by not introducing non-native species; Home-grown worms – not required to order worms, just find some, put them together, let them reproduce (need 2 lbs worms = 2000 per lb food waste per day); Soil foodweb – fungi, bacteria, microarthropods, nematodes, protozoa, beetles, sow bugs, springtails, centipedes, earthworms (whatever is native to the soil); Ecosystem food chain – bacteria and fungi eat the organic matter; protozoa and nematodes eat the bacteria and fungi; red worms feed on the protozoa and nematodes; the red worm castings have high nitrogen content and are used by plants; red worms either die or are preyed upon by centipedes and rodents; Bedding – shredded newspaper, cardboard, shredded leaves, straw, dead plants, sawdust, peat most, compost, manure.

22. GREEN CONSIDERATION OF VERMICOMPOSTING SYSTEMS
OUTPUT = WORM CASTINGS
How useful is the output? Worm castings – case study results: (tomato growing in CA) four soil conditions (1) plain soil, (2) soil with steer manure, (3) soil with worm castings, (4) soil with worms and castings; plain soil and soil with manure were nearly identical, (3) increased production by 10% and (4) increased production by 33%. Another study: (Cuba) 4 metric tons/ha replacing 45 tons/ha manure increased production 31%.

23. Summary and Conclusions
Simple, effective
Contributes to sustainability by reducing landfilling, closing loop from food chain
Improvements 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?