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Shredders help turn garbage into valuable raw materials

When most people throw their garbage away, they don’t give it a second thought. It is gone when they get home from work, the trashcan hugging the curb, empty and waiting for more trash, oblivious to the fact that the garbage must end up somewhere. As land grows ever scarcer, landfills have to become more and more efficient, employing all kinds of technology to reduce landfill waste to a minimum and to maximize recycling. The EPA estimates that 75% of what Americans throw in the trash could be recycled. Currently only 32.5% is recycled or composted, leaving 42.5% potential for growth.

One of the more helpful tools for this is the shredder. These machines can take even bulky and difficult items such as waste wood and commercial refuse, as well as household waste, and shred them down to a uniform, manageable size so they can be further screened and recycled or reduced in size even further. With landfill sites running out of space, shredding has been most welcome in reducing waste bulk. It is also the first step in separating materials into “fractions” for recycling or energy generation.

Traditionally, the shredder has been powered by a diesel engine, but it’s becoming more common for them to be driven electrically. Typically, wheels or tracks are incorporated so it may be moved as needed at the site. A toothed cylinder called a “drum” rotates against a “comb,” pulling the waste down and shredding it into pieces of the desired size. At one end, the waste might consist of old building materials, tires, rootstocks, metal waste, and even railroad ties, while at the other end the conveyor discharges a stream of uniform-sized fragments for further processing. This can now be screened and sorted for recycling or even reclaimed for energy.

Screening and sorting can take various forms, including magnetic separation, mechanical sifting, and “wind” to blow out light items like plastics. Shredding makes it easier for screening machines to separate waste into homogenous fractions of different kinds of materials – wood, metal, plastics, etc.

With fuel prices soaring, waste management operators are trying to do everything possible to be more efficient. In the past, fuel costs were negligible, but now rising prices make it a critical budget factor. A company called Komptech addresses this with powerful, high torque, low rpm shredders that deliver all of the tooth force at lower speed, and thus greater fuel economy. This can translate into hundreds of dollars saved in daily operating costs.

Because Komptech is based in Austria where fuel costs have always been higher, these machines were engineered from the very beginning with efficiency in mind, as well as low noise and emissions.

The drum rotation speed is dependent on the workload, so it always works at optimum efficiency, resulting in greater fuel economy and taking full advantage of engine output. The shredder drum can generate peak tooth force at speeds as low as 10 revolutions per minute, without compromising engine performance.

For applications not requiring mobility, the company offers stationary shredders with electro-mechanical direct drive and an asynchronous motor. Because there are no hydraulics, there are fewer moving parts and no hydraulic oil changes, so service costs are minimized and even less resources are used.

Already, municipalities that separate and recycle waste can make a profit from the resale of waste fractions as raw materials, for manufacturing, building, or energy generation. Shredders are indispensable for reducing waste volumes, and when used in conjunction with screeners that sort waste into sellable commodities, they contribute to a landfill’s bottom line. As shredders become more efficient, the rewards of reclaiming, reusing, and recycling resources will only grow.