KMI

Single stream recycling systems do not require consumers to pre-sort recyclables. All items designated as acceptable can be tossed into a single container. These items are then sorted at a material recycling facility into pure streams of materials.In recent years, large single stream recycling equipment has been developed which can effectively sort mixed recyclables with an exceptional record of accuracy, and at rates up to 50 tons per hour.

Collection costs are significantly reduced when single stream recycling equipment is used. Trucks with one compartment are cheaper than those with multiple bins. Collection can be automated. In addition, consumers recycle more items when their portion of the task is simplified.

Single stream recycling equipment may also make it possible for a greater variety of materials to be collected, such as more types of plastic, and more grades of paper.

Varied technologies and hand sorting are used in combination to separate the commingled waste. One such arrangement is:

• The mixed stream is fed into a hopper which tumbles and loosens the mixed waste
• Large metal and plastic items, such as small appliances or laundry baskets and toys, are removed by hand. Plastic bags, which clog machinery, must also be removed by hand.
• Rotating paddles flip the large pieces of cardboard out of the stream, leaving mixed lighter papers and containers
• A series of augurs crush glass, which can then be screened out the bottom of the line
• Paper is removed from the stream in a combination of hand sorting, and by using rotating rubber paddles which catch the flat paper, but allow containers to continue on the conveyor.
• Optical and infra-red scanners, combined with manual processes, separate plastics.
• Ferrous metals are removed by magnets, and aluminum can be forced from the stream by electrostatic repulsion
• At multiple points, hand sorting continues to be useful for separation and purification of the stream.
• A final manual inspection is made to remove any recyclables which may have passed through the single stream recycling equipment

The separated items may be baled and are then transported to manufacturing plants which use the products as raw material.

Modern sorting equipment can produce bales of product with greater than 95% purity. High throughput of commingled waste is required to recover enough material to pay for the systems. Successful single stream operations generally accept recyclable waste from a dozen or more communities.