Science Video

Recycling Without Sorting
Engineers Create Recycling Plant That Removes The Need To Sort

October 1, 2007 — Engineers use the term single-stream recycling for their plant that takes the sorting out of the public’s hands. Trucks dump an unsorted mess of paper, plastic, and metal onto a conveyor belt. Magnets, air blowers, and optical scanners separate the items, making it possible to recycle the different products.

Recycling programs have been underway for years, but Americans still lag behind on recycling efforts. The biggest reason -- it's inconvenient.

If you recycle, you know the drill ... separate ... separate ... separate ...

"In the early years, we've had to separate things fairly significantly," recycler Steve Snowden says.

Now, Snowden's separating days are over. A new program called "Single Stream Recycling" allows you to put all recycle items into one container.

"We like it quite a bit because it is so easy," Snowden says.

Leaving the rest of the work up to someone else!

"We do the separation to mechanically separate the materials here at the recycling facility," says Michael Taylor, environmental scientist from Waste Management Recycle America, who developed the system.

Fast, rotating devices separate newspaper and cardboard from cans and glass that tumble to another level. Magnets grab metal cans and optical scanners recognize plastic from other items and trigger blasts of air to blow plastic into another bin.

"Highly-engineered, highly complex mechanical systems do the work in a much more efficient, much more cost effective and much more significantly faster-paced environment," Taylor explains.

Environmental scientists have seen an increase in recycling of almost 30-percent among homeowners who use the system.

"We're much more liable to do something the easier it is to do it," Snowden says.

There are 27 Waste Management Recycle America "Single Stream Recycling" facilities in the country. There are also other recycling organizations that use Single Stream.

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

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.


* Recycle all paper (junk mail, boxes, magazines, envelopes), bottles and cans (aluminum, glass, metal, and plastic).

* Buy products with little or no packaging, and buy the largest size you can use.

* Buy reusable products such as non-disposable cameras, electric razors, reusable lunch boxes, etc.

* Bring your own mug to the office or local coffee house for coffee; paper cups waste both money and landfill space.

* Buy products made with recycled materials.

* Reduce your junk mail by canceling unwanted catalogs.

* Bring your own reusable grocery sacks when shopping at the local supermarket.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.

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