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

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

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

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.

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.

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

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

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

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.

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

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.

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.

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)

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.

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

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”.

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

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

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.

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.

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.

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%.

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?