Composting 101

Composting organic materials such as yard trimmings, food scraps, wood waste and paper are helps to manage the largest component of our trash the garbage waste we dispose of, making up more than two-thirds of the solid waste disposal stream. The amount of yard waste and its municipal solid waste 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. Composting serves as an environment friendly waste disposal solution by cutting down on the amount of garbage waste headed to landfills. State and local composting requirements have increased the number of commercial composting operations.

What is composting?

Composting—which involves the controlled decomposition of plant remains and other organic materials to make an earthy, dark, crumbly substance that is excellent for enriching soil and preventing soil erosion—is a great way to recycle yard and kitchen wastes and reduce the volume of garbage waste sent to landfills or incinerators for disposal.

Natural composting, or biological decomposition, began with the first plants on earth and has been going on ever since. As vegetation falls to the ground, it slowly decays, providing minerals and nutrients needed for plants, animals, and microorganisms. The production of “mature” (or usable) compost from organic wastes also requires high temperatures to destroy pathogens and seeds that natural decomposition does not destroy.

All garbage waste composting requires three basic ingredients: browns (including materials such as dead leaves, branches, twigs, wood chips or cardboard); greens (materials such as grass clippings, vegetable waste, fruit scraps and coffee grounds) and water.

Mature compost contains “humus,” a dark brown or black substance with a soil-like, earthy smell. It is created by combining “greens” with “browns” in the proper ratio with water to accelerate the breakdown of organic materials, and then allowing the finished compost material to fully stabilize and mature.

Environmental benefits of waste composting

There are a number of environmental benefits to composting garbage waste:

• Composting organic matter rather than disposing in landfills reduces the emission of greenhouse gases like methane.
• Using compost as fertilizer reduces the need for chemical fertilizers, and promotes higher crop yields.
• Compost can regenerate poor soils, and can be used to cleanup (or remediate) contaminated soil by absorbing odors and treating chemicals. Compost has also been shown to bind to heavy metals and prevent them from migrating into groundwater or plants.

Municipal waste composting and home waste composting

Some municipalities offer curbside collection for yard waste in the same way recyclables are collected. The waste is taken to a centralized location where it is turned into compost that may be sold, given away or used in public works projects.

You can create your own home compost from garbage waste as well, either in your backyard or indoors using a compost bin, depending on your available space. Backyard and indoor composting work best for households when focusing on converting small quantities of organic waste materials, such as yard trimmings and food scraps, into compost that can be spread in garden beds and under shrubs, or used as potting soil for outdoor plants. Waste Composting can be done with a variety of different systems or containers, including kitchen sized compost bins. You can construct yours at home, or buy a compost system in a garden supply or home improvement store.

The U.S. EPA’s web site features an excellent how-to guide on home waste composting. You can also check the EPA web site to find out more about municipal waste composting programs in your state.

(sources: Waste Age; EPA; California Integrated Waste Management Board; How to Compost; Biocycle, January and April, 2006; Composting Council, Amherst, OH; Cornell Waste Management Institute; “Measurement Standards and Reporting Guidelines,” National Recycling Coalition; “Municipal Solid Waste in the United States: 2005 Facts and Figures,” Office of Solid Waste, Washington; *2005 EPA estimates)

Want to learn more?

• Click here to learn about preventing litter.
• Click here to learn about the solid waste management process.
• Click here to learn more about how the solid waste industry facilitates recycling.