Food waste includes uneaten portions of meals and trimmings from food preparation. It is the second largest component of generated waste by weight and the largest component of discarded waste by weight.

Estimates of the amount of food waste vary widely. The U.S. Environmental Protection Agency states that each of us discards less than a pound a day or 209 pounds a year. But a study by the University of Arizona Garbage Project shows a per-person food scrap rate of 1.3 pounds per day or 474.5 pounds per year. The U.S. Department of Agriculture also shows more food waste than EPA.

Over 60 million homes and 500,000 businesses have in-sink food disposers that divert food waste from landfills. Although food waste composting has been held back by cost, siting and vector control concerns, large-scale projects in San Francisco, Seattle and Toronto are breaking new ground.

Food waste's share of the solid waste stream decreased by 9 percent from 1960 to 2007 because of increased consumption of packaged foods and the use of disposers. During the same time period, increased package and paper recycling caused food waste's share of the disposal stream to increase by 23 percent.

Chaz Miller is state programs director for the National Solid Wastes Management Association, Washington. E-mail him at: cmiller@envasns.org.