January 21, 2005 | General

Backyard Composting Developments

BioCycle January 2005, Vol. 46, No. 1, p. 45
Municipal programs reach out to different sectors as new ways are developed to expand at-home organics diversion – and they’re working impressively!
Rhonda Sherman

VARIATIONS of backyard composting may be found in every state, plus the District of Columbia. In some municipalities, backyard composting is considered a key waste diversion tool, and they offer subsidized bin distribution programs, monthly classes, and hotline support. Other communities have backyard composting education programs that distribute fact sheets and offer occasional classes. The Cooperative Extension Service in most states is promoting backyard composting to some extent through Master Gardener, Composter or Waste Manager programs.
However, many municipalities are experiencing budget cuts for solid waste management services, and managers have had to scale back their backyard composting programs. With limited resources, program managers have to set priorities for diverting specific solid waste materials. Currently, electronics are “hot,” so many municipalities are focusing on electronics recycling events rather than on compost bin distribution programs.
“In past years, through municipally-supported backyard compost (BYC) distribution programs, millions of bins have been distributed in the United States,” says Amy Freeman-Rosa, sales representative for Earth Machine East through Norseman Plastics. “Recently, BYC programs have had to share limited resources with new waste reduction programs such as electronics recycling. But backyard compost bin distribution programs are a viable waste reduction tool and there is a new level of interest in composting, not only from the waste reduction prospective, but the utilization of compost to improve the soil and conservation of water.”
One city that endorses backyard composting as a key waste diversion tool is Seattle, Washington. Food residuals comprise one-third of a typical Seattle resident’s garbage, so those who process organics at home save the city a tremendous amount of money. “Composting food wastes at home helps to save landfill space and saves money for both residents and the city. When you add the economic benefit to the environmental benefit, it’s a powerful equation,” says Carl Woestwin, program manager for Seattle Public Utilities (SPU).
In 2000, Seattle Public Utilities estimated that households that were backyard composting and grasscycling had an average annual household recovery rate of 562 pounds of yard trimmings. Those who were composting food scraps diverted an estimated 290 pounds of food per year.
Backyard composting and in-ground food digestion was one of the first new programs introduced by Seattle Mayor Greg Nickels to boost recycling rates to reach a 60 percent diversion goal. Seattle’s goal is to disperse food digesters to 20,000 households over the next 8 years, at a rate of 2,500 per year. Over the past 12 years, 11,000 Green Cone food digesters have been distributed to over 8,000 households. During their kickoff promotion last March, Seattle offered a 75 percent discount on composting bins to residents. Citizens could buy one Green Cone Food Waste Composter for $25 or two for $40. Yard waste compost bins sold for $25 each, limited to one per household. In one day, SPU sold 5,000 backyard bins: 3,600 Green Cones and 1,400 yard waste composters.
Green Cone food digesters have three sections-an in-ground basket, an inner opaque black cone and a green translucent outer cone with a lid. The basket is 16.75 inches tall and 22.5 inches wide, so a hole of those dimensions needs to be dug to bury it. Food scraps go into the basket and soil microorganisms break them down into humus. The translucent outer cone allows sunlight to penetrate and heat the layer of air between the two cones. The unit usually sells for $100-$130. Green Cones were chosen by SPU because of their durable construction and established track record in the United States and United Kingdom.
Communities are changing how they promote backyard composting. To keep the number of participants increasing, West Coast programs are focusing on people who are not familiar with composting. “We’ve saturated the market with people who know what compost is and want to compost,” says Michele Young, coordinator of backyard composting for the city of San Jose, California. “On the West Coast, there is a shift to integrated programming. We’re going to the next level, to educate people who aren’t familiar with composting, like gardeners and those who are concerned about using pesticides in their yards.” For example, San Jose is focusing on the connection of backyard composting to natural landscapes, and Alameda County has a Bay-Friendly Gardening Program that educates residents on how to reduce yard waste and protect local waterways and watersheds that drain to San Francisco Bay.
Seattle has shifted to a Natural Lawn and Gardening Program, of which backyard composting is a component. Home composting is promoted as “one of the best and easiest things you can do to grow a healthy, sustainable garden.” Some of the advantages of home composting touted by Seattle are that residents do not have to “bag and drag” their yard wastes to the curb for collection, pay to have them hauled to a composting facility, or buy finished compost.
Putting a new spin on composting is especially important in King County, Washington, which gave birth to the backyard composting movement in the 1980s. Nowadays, the County promotes backyard composting as a tool for building healthy soils. King County has a poster that is essentially about composting but it does not mention the word “compost.” Instead, the poster shows how air, water and soil are linked, and explains composting by connecting decomposition, organic products and a healthy ecosystem. On King County’s website, they stress that “healthy soil is critical for good air and water quality and the health of our lawns and gardens…learn how you can improve your soil and how composting can restore soil to make plants grow and yards healthy.”
Integrated programming is taking place on the East Coast as well. Maryland is one of the most active composting states, and it is largely due to coordinated efforts to protect the Chesapeake Bay. Composting managers have been partnering with watershed and water runoff administrators to help safeguard the fragile ecosystem. Compost is growing in popularity because it can replace chemical fertilizers. Reducing runoff of chemicals from standard fertilizer products is a major goal of efforts within the Chesapeake Bay region to restore the streams and rivers that feed into the Bay.
Freeman-Rosa offers the following conclusion about backyard composting: “Even using the very conservative figure of diverting one-third of a ton per household per year from disposal, it is evident that backyard composting is a very viable tool for waste reduction. Depending on local landfill tipping fees, municipalities can save $15,000-$20,000 in one year by starting a backyard composting program.”
Rhonda Sherman is a freelance writer and university faculty member in Raleigh, North Carolina.
COMMERCIAL backyard composting bins are typically either open or closed cylinders, revolving drums, or orbs that you roll along the ground to turn the pile. In the past couple of years, some new innovations in home composting systems have emerged in the marketplace. Many of the new bins are designed specifically to process food scraps.
According to Amy Freeman-Rosa, a compost bin distributor, essential features are roundness and smoothness of the insides of bins so that materials don’t get hung up or trapped in corners; locking lid to keep from blowing off; well ventilated to keep the pile aerated and rodent proof.
The following commercial compost bins have innovative features and are listed in order of increasing cost:
Bokashi Kitchen Composter from Japan is designed for indoor composting in apartments and condos. The unit anaerobically ferments food scraps using the patented Bokashi method of beneficial microbial inoculation (which includes water, wheat bran, molasses, EM-X ceramic powder and efficient microbes), and reportedly speeds up the decomposition process. The bin is 16 inches high by 10 inches wide by 10 inches deep, and sells for about $50. A one-gallon bag of BKC activator costs around $12.
Flowtron Expandable System is an interlocking, expandable unit that can be reconfigured according to ones’ composting needs. It can be interlocked as individual bins – one for fresh waste, one for more mature compost, and one for finished humus. Or the five adjacent slats can be removed to make one huge bin to accommodate large amounts of organic materials. Or all four sides can be interlocked with adjoining bins for a variety of combinations. Removable 5.5 inch slats have half-inch gaps between them for aeration, and the two bottom slats on each side can be removed to access finished compost. Each interlocking bin is 30 inches high by 30 inches wide by 32 inches deep. One bin is around $100 and the price decreases for sales of multiple units.
Green Johanna Hot Komposter has a patented ventilation system that continually circulates air throughout the bin and decomposes all kitchen wastes. A twisting-lock lid helps keeps animals and children out. The unit includes a pile turner and comes with an optional insulation jacket for cold climates. The 37 inch high by 32 inch base unit has an 11 cubic foot capacity and costs about $150.
Indoor Outdoor Composter mixes food scraps, peat moss and water (2:1:1 cup ratio) in a drum that is turned with a handle. The unit is 33 inches high, 24 inches wide and 23 inches deep. It processes food scraps from 5-6 people at home or 8-9 people in office settings, and costs about $350.
Scrap Eater Living Machine uses a recycled Bordeaux wine barrel that doubles as a garden planter. Designed as a miniature ecosystem, plants grown in perimeter soil derive nutrients and water directly from the composting section. An acrylic dome over the composting area uses solar energy to heat the organic materials, and keeps animals out and odors inside the chamber. The 28 inch high by 28 inch diameter unit processes food scraps from two to four people and sells for about $370.
RotoTherm CrankTec System is advertised as the only bin that stirs and screens compost. A crank slides across the top to stir compost in the middle and sides of the bin. There are 380 air holes to promote aeration and decomposition. The 42 inch high by 42 inch wide bin has a capacity of 25 cubic feet. It costs around $550.
Increasing interest is becoming evident in pet manure composting. Commercial systems include a worm bin and in-ground digesters that accept most pet wastes, including those from cats, dogs, birds, horses, pigs and rabbits.
Digester systems are designed to be buried in the ground and use added enzymes to dissolve feces. Pet-D-Posit In-Ground Waste Digester sells for $20, Doggie Dooley Pet Waste Digester System costs $45-$50, English Pet Waste Digester costs $55, and In-Ground Pet Drums sell for $45-$50 (plastic) and $55-$60 (aluminum).
Tumbleweed Pet Poo Converter is a worm bin that has an upper level for processing manure and a lower section for collecting worm castings. The 23 inch long by 15 inch wide by 13 inch high unit sells for about $90 and can process manure produced by two dogs.
A major concern about handling pet waste is the likely presence of human pathogens. People have similar concerns about small compost piles and worm bins because high temperatures are not achieved, and consequently, the potential for the survival of pathogens is increased. Cornell University’s Waste Management Institute addressed this issue in their study Hygienic Implications of Small-Scale Composting in New York State. Cornell tested 20 small compost piles and compared their results with the pathogen standards established by the US-EPA for composted sewage sludges. The composts generally met those standards, and Cornell researchers concluded that when good hygiene practices are used in small-scale compost settings, the relative health risks are low. The research results led Cornell to recommend the following guidelines in their fact sheet titled Health and Safety Guidance for Small-Scale Composting: 1) Avoid putting meat, pet feces, and plate scrapings from ill people into compost piles; 2) Try to get and keep your pile hot long enough to reduce pathogens; 3) Wash hands after handling compost or use gloves; 4) Use caution when handling compost if your immune system is compromised; and 5) Allow compost to age for at least a year before use.

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