Yard Waste 4440
The rate of composted yard waste has soared in recent decades.
Yard Waste Includes Grass, leaves, and tree and brush trimmings. By weight, grass is the biggest component, averaging half of all yard waste, with leaves and brush each comprising one quarter. By volume, leaves are the biggest component.
Yard waste is the largest single component of generated MSW by weight but is a relatively small component of landfilled MSW by volume.
The amount of yard waste and its MSW disposal market share have declined dramatically in the last four decades while the composting rate has soared. Backyard compost piles and “grasscycling” programs have helped to reduce yard waste generation. State and local composting requirements have increased the number of commercial composting operations.
Composting is the controlled decomposition of organic matter by microorganisms into a humus-like product. Waste and carbon dioxide dissipate into the atmosphere. Up to 75 percent of the volume and 50 percent of the weight are lost through composting.
Composting requires aeration, temperature control (132-140 degrees Farenheit), stable moisture content (40-60 percent) and an adequate carbon-to-nitrogen ratio. Improper operation can create odors and allow the growth of a hazardous fungus (aspergillus fumigatus).
Chaz Miller is state programs director for the National Solid Wastes Management Association, Washington, D.C. E-mail the author at: [email protected].
Sources:
Biocycle, January and April, 2006, www.biocycle.com
Composting Council, Amherst, OH, www.compostingcouncil.org
Cornell Waste Management Institute,
www.cfe.cornell.edu/compost
“Measurement Standards and Reporting Guidelines,” National Recycling Coalition, www.nrc-recycle.org
“Municipal Solid Waste in the United States: 2005 Facts and Figures,” Office of Solid Waste, Washington, www.epa.gov/osw
*2005 EPA estimates.
Yard Waste Municipal Solid Waste Facts:
Generated:
32.1 million tons or 13.1% by weight.*
216.6 pounds per person.*
Composted:
19.9 million tons, or 61.9% composting rate.*
Almost 3,500 yard waste composting facilities operating in the U.S.
Compost can be produced in as little as three months.
Compost provides one fourth of America's recycling rate.
Incinerated or Landfilled:
12.2 million tons or 7.3% of discarded MSW.*
Percentage sent to disposal has steadily declined for three decades.
2,876 Btus per pound versus 4,500-5,000 Btus for a pound of garbage.
Several states ban the burning of yard waste piles.
Yard waste disposal is banned or restricted in 24 states.
Landfill Volume:
21.7 million cubic yards or 5.1% of landfilled MSW in 1997.
Density:
Uncompacted yard waste weighs 250-500 pounds per cubic yard (lbs./cu. yd.).
Landfilled yard waste weighs 1,500 lbs./cu. yd.
Source Reduction:
“Grasscycling” or “leave it on the lawn” programs and backyard composting combined to make yard waste the most source reduced item in the waste stream.
Brush can be shredded into mulch.
Xeriscaping (landscaping with plants that need small amounts of water and produce small amounts of waste) reduces yard waste.
Composting Markets:
Yard waste compost is a useful soil conditioner that improves texture, air circulation and drainage, moderates soil temperature, enhances nutrient and water-holding capacity, decreases erosion, inhibits weed growth and suppresses some plant pathogens.
High quality compost is used as a soil amendment and mulch.
Can be used as landfill daily cover.
Compost processors often charge a tipping fee.
End-Market Specifications:
Vary by market.
Keep non-organic materials out.
Tests indicate little heavy metal contamination.
About the Author
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