Reported October, 2007

BACKGROUND: Elkridge, Md., is home to a single stream recycling plant, in which glass, plastic and metal are all mixed together and the plant sorts everything out. The plant recycles 1,000 tons of garbage every day.

PROS AND CONS: If residents don't have to maintain separate containers for their glass, bottles, paper and plastic supporters of the plant say that this encourages more people to participate in recycling. Residents can simply load all recyclables into a single container to be sorted at the plant. It also reduces costs for local governments, because less expensive trucks can be used if the waste material isn't sorted beforehand. Trucks cost $50,000 each more equipment to keep paper and other materials separate, for example. Critics say such a single-stream plant is inefficient and diminishes the usefulness of the materials collected, because it opts for speed to process the vast quantities of mixed recyclable waste it receives. There is more contamination as a result, which degrades the quality of what is sorted.

HOW IT WORKS: The plant uses a variety of sorting devices, including screens, magnets and ultraviolet optical scanners that trigger blasts of air to separate plastic bottles from the rest of the items, as well as spinning, star-shaped plastic devices that separate newspaper from cans and bottles by pushing the paper higher up an inclined screen so the heavier, smaller cans and bottles tumble down to a lower level. Glass is sorted by color and crushed, while plastic is shredded into small chips.

The Materials Research Society and the Optical Society of America contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Wes Muir
Director of Communications
Waste Management Inc.
(905) 483-3099
wmuir@wm.com

Materials Research Society
Warrendale, PA 15086-7573
(724) 779-3003
webmaster@mrs.org

Optical Society of America
Washington, DC 20036-1023
(202) 223-8130
http://www.osa.org
info@osa.org