by Jon M. Casey

When it comes to recycling wood waste, MSW and C&D materials, nothing beats a low speed shredder to help get the job done. With more than a dozen brands of portable shredders available to recyclers in the U.S. market, it comes as no surprise to find that recyclers have come to realize the usefulness of the low speed shredder. In many cases, a low speed shredder is used as a first grind for wood products like mulch and biomass. In other instances, they are used as the sole reduction tool, capable of shredding everything from mattresses and carpets to whole automobiles and everything in between.

In this photo layout, I wanted to share a few recollections of shredders that have appeared in WHEN over the past five years or so. These machines were used in a variety of applications and we will see that they are surprisingly versatile tools for recyclers. Interestingly, new models have continued to come on the scene, suggesting that market research has discovered that there is an increasing demand for the low speed shredder. While I have not had the privilege of seeing every brand that is available in the U.S. to date, I have had the opportunity to witness most of the ones shown here in action. I’ve not seen an EDGE nor a TANA shredder in person, however these two companies have been in business for a number of years in Europe and have successful sales in that market.

With more than a dozen manufacturers in the U.S. marketplace, this comparison is by no means comprehensive in its scope. More importantly, the information found here is from manufacturer’s literature and is not an endorsement of their products or service. I make no claims as to which unit is best suited for any buyer. I thought it would be interesting to see several of them in the same place at the same time! Note that in many cases, the various brands offer different sizes and models of portable shredding units and most come with a number of optional features that can help tailor the shredder to the user’s application. Different shredding shaft designs, methods of transport, varying horsepower ranges and power plants, give buyers the flexibility they need to do the best job at their specific operations.

First on the list, and in no particular order is the Komptech Crambo 6000. This unit is frequently found in wood waste applications where it makes an excellent “first grind” shredder. Yard waste can easily be turned into coarse mulch or a uniform biomass material that is ready for market with the use of the desired screen baskets. Available in two to 12-inch sizes, the screen baskets are easy to change. The Crambo comes in three models, the 3400, the 5000 and the 6000 shown here. Each model is available as a stationary unit, a towable trailer style on wheels, and a tracked unit as shown.

The recycler using the unit shown said they have found that by using the Crambo 6000 to do a first grind, the wear and tear on equipment is much less and their fuel consumption overall is reduced. The low speed shredder isn’t as hard on teeth and wear parts and the replacement time for the wear parts in the high speed grinder is extended which saves us money as well. He noted that the incoming material is shredded with the Crambo and it can be loaded directly into trucks and sold as biofuel or it can be stockpiled to sell as a construction grade material. They can also run it through their high speed grinder as a second grind material that can be sold as natural mulch or processed through their coloring system.

Next is the Doppstadt DW-3060 K. Doppstadt’s DW shredder line currently offers seven versions of this single shaft design. From the DW 2060 on the low end to the DW 3080 K at the top, recyclers will find units available in wheel or tracked versions with the DW 3060 SA model mounted on a semitrailer chassis for easier transport from site to site.

As you can see from the on-site photo of the DW-3060 K taken by William Weaver, the shredder does an excellent job reducing MSW material for further processing. The Doppstadt DW 3060K is designed to operate at a slow 34 rpm, with a high torque, single shaft tooth and comb design. In this landfill application, bulky MSW goes from the shredder to a Doppstadt Trommel Screener, which is used with a 1-¼-inch screen to remove metal from shredded MSW. The screened material is then burned. The Doppstadt Shredder has also been useful for efficient handling of an item that is the bane of landfill operators everywhere: mattresses. After the mattresses are shredded by the Doppstadt into pieces less than 10-inches in size, the material makes great fuel for the burn units, as do old carpets, carpet padding, and upholstered furniture.

The next two shredders, the Terex TDS 820 low speed shredder and the Terex TDS V20 medium speed shredders are shown being demonstrated at the Compost 2016 event in Jacksonville, FL. The TDS 820 is a double shaft, low speed shredder that is suitable for all types of materials, like for wood waste as shown here to scrap metal recycling. This tracked shredder, with its independently driven shredding shafts, offers excellent performance, even in the most challenging applications.

The Terex TDS V20 medium speed shredder was specifically designed for the mobile recycling industry. With a double shaft shredding chamber designed by Vecoplan and hydrostatic drive, this shredder is versatile enough “to shred wood waste, green waste, domestic and industrial waste and is particularly suited to producing specified recovered fuel (SRF). The TDS V20 operates at a higher processing speed than a conventional low speed unit does but is slower than the high speed grinders that are commonly used in the recycling industry.”

A new entry into the U.S. shredding market is the PRONAR MRW 2.85 slow speed shredder, a unit manufactured in Poland. Introduced at Compost 2016, this twin shaft wheel mounted shredder is rated at a maximum shaft speed of 44 rpm and powered by a six cylinder CAT diesel engine. Since there were no actual units on exhibit or in demonstrations at that show, I have no first hand knowledge of the unit’s operation or effectiveness. Nevertheless, it’s interesting to note that as recent as this spring, new shredders are still coming to the North American market.

The next three shredders on review are reasonably new to the U.S market as well. The HT1042 single shaft, slow speed shredder from Morbark, the URRACO 75DK twin shaft, low speed shredder from Lindner and the METSO M&J Eta® PreShred 4000 all have been available in the US for less than three years. The Morbark model is a new product in the Morbark line and was introduced at ConAGG/CONEXPO in 2014. The Lindner tracked portable is a new addition to the Lindner line, a company that is known in Europe for its successful history in stationary shredding equipment. The Lindner 75 DK and it’s bigger “brother,” the 95DK are powerful, yet compact shredders that offer high throughput. Available in wheeled and tracked models, these versatile shredders have a lot to offer. Outfitted with the PowerLine option, the units offer up to 30 percent increased output capacity due to an enhanced gearbox that provides increased torque and a reinforced hydraulic system for more power. The “Powerline” version of the 75DK model is rated at up to 60 tons per hour of wood waste shredding. One user said that the 75DK only uses about five gallons of fuel per hour shredding wood waste, because it is powered by a 350 hp Tier 4 diesel engine. The third of the newer arrivals is the METSO M&J Eta® PreShred 4000. This unit was first seen at the WHEN Expo North in 2013. The twin shaft unit made quick work of C&D waste during the field demonstrations, taking in everything from sheet rock to mattresses and carpet.

Last, but not least, is the Hammel VB850 DK twin shaft primary shredder. One of Hammel’s five units in their low speed shredder line, these shredders are available in stationary, mobile on tracks and semi-mobile on frame or wheel axle. Available in five sizes from the VB 450 to the new VB 1500, a yet larger machine than the familiar VB 950, more commonly known as “The Red Giant.” Weighing in at 60 tons, the VB 1500 is billed as the world’s largest mobile shredder. The VB 850 shown in the demonstration is a medium-sized Hammel unit that still possesses the capability to shred automobiles, engines and all. These German manufactured units are recognized for their quality engineering and powerful processing capabilities.

For more information on any of these manufacturers, visit their company websites. In order of description: Komptechamericas.com ; Doppstadt.de/en/ ; Terex.com/environmental-equipment/en/index.htm ; pronar.pl/en ; Morbark.com ; l-ms-de/en/home/lindner-mobile-shredder.html ; metso.com/products/waste-recycling/MJ-PreShred-4000-stationary/ and hammelny.com .