Compost Windrow Turners vary in size, shape and color

008by Jon M. Casey

After attending the U.S. Composting Council’s Compost 2016 event in Jacksonville, FL in late January this year, I thought it might be interesting to share some of the photos of the various machines that were operating on Thursday’s Demonstration Day at J.B. Coxwell Contracting’s Otis Road Landfill. I thought it might offer food for thought for shoppers when considering the purchase of a compost turner. While I do not consider myself an expert on the topic in any way, the purpose of this article is simply to enjoy comparing and contrasting a few of the features that shoppers consider when purchasing a compost turner.

With more than a dozen manufacturers in the marketplace and that number possibly approaching two dozen, this comparison is by no means comprehensive in its scope. More importantly, I make no claims as to which unit is best suited for any buyer. Actually, that seems to be the beauty of the Compost Turner market place — there’s very probably a brand or model that will meet your needs in virtually every respect. Even within the product lines of each manufacturer highlighted here, there are multiple choices on size, power, propulsion and other options, so the choices almost multiply exponentially. One company may offer only one model with several options while another may offer seven to ten models, each with specific design characteristics.

So, for the sake of our discussion today, we will be using the Terex Environmental Equipment (TEE) TWT 500, the Vermeer CT 718, the Backus A 55 from Ecoverse, the Kompech X55 and the Midwest Biosystems Aerotech PT 170 as our resources. The individual manufacturer’s published equipment spec sheets, found online, have supplied technical information in this article. Any performance claims come from these sources and they have not been verified independently.

According to Dave Whitelaw, a respected industry veteran, the top considerations that buyers have when shopping for a compost turner are, the amount of material to be turned, the windrow size, the machine horsepower needed to do the job effectively, fuel consumption, machine portability, whether the unit moves on tires or tracks, automatic controls and operator cab safety and comfort. The buyer, may express any or all of these concerns in a number of ways, however these are their main considerations in most cases.

For example, if the shopper does not want or need a self-propelled turner, then similar features and benefits of a pull behind model would need to be compared. For those who have enough composted material to justify a self-propelled unit, the added considerations of engine size, horsepower, fuel consumption and maintenance are all on the table at that time. Since some units are hydraulically driven while others are direct belt drive, fuel consumption may be significantly lower on the hydraulic units when compared to the belt driven models of equal size.

How much material needs to be turned and how frequently it is scheduled to be turned is a primary consideration. In the case of the machines shown at Compost 2016 that range varied from 2,600 to 2,800-cubic-yards per hour for the Aeromaster and Terex units respectively, to as much as 4,000 to 6,000 (3,000 tons) cubic-yards per hour for the larger Komptech, Backhus and Vermeer units. Those differences translate into a daily production rate of 20,800 yards per eight hour day on the lower end to as many as 48,000 yards of material per day on the higher end. In one week, that’s a production rate of between 104,000 yards per five day week to 240,000 yards per week for the larger units. Therefore, how much material needing to be turned is a key element in the decision making process.

The next item to consider is the size of the windrow both in height and in width. Often, the size of the windrow is related directly to the total amount of surface area devoted to the windrows. If the total available space is limited, windrows might be higher, wider and closer together than where composting space is not an issue. If windrows need to be touching side by side at the base, to maximize volume per site, and there’s no room for a tractor or for a unit that has exposed wheels or tracks, then that will affect the buying decision in the end.

Machines like the Komptech X55 and the Backhus A-55 have diverter plates that gather material sitting in front of the wheels or tracks that help keep the compost out of their way. The Terex TWT500 is designed with the tracks behind the infeed scoop, a feature not found on the other designs shown. While the material is turned with a drum on those in these demonstrations in the TWT500, the drum/scoop design feeds the compost into a conveyor that discharges the material behind or to the side (optional) of the unit. With the pull-behind Aeromaster, an aisle is a necessity for this unit, however Aeromaster does make a self-propelled model that was not demonstrated at this event, thus not included in the comparison.

Windrow height and widths in our examples can vary from 6.5 x 14-feet on the Aeromaster up to 8 x 18-feet on the Backhus. Larger and smaller capacity models are available from most manufacturers. Currently, TEE only offers one model.

The next two considerations, horsepower and fuel consumption generally go hand in hand. The larger the engine needed to do the job, the less fuel economy the machine will have. Aside from the pull-behind PT170 from Aeromaster, which requires a 130 to 140 hp tractor with 1000 rpm PTO for its propulsion, the other self-propelled models are all diesel power plants of various make including CAT, John Deere and Volvo. Other engine brands are available on some makes of equipment depending on the turner’s size and power needs.

Tires or tracks and portability are important considerations as well. As mentioned earlier, sometimes the layout of the composting surface will determine the kind of ground drive that the unit would require. If rough, uneven or slippery surfaces are a consideration, then tracked units might be a better choice. Turning radius might also dictate whether a zero turn/short turn configuration is more desirable than a machine that requires a larger turning radius. Likewise, if the need for transporting a machine from site to site is part of the plan, then a model that does not need special permitting or disassembly and reassembly might be more desirable. For example, the Backhus cab lowers down to near ground level, giving the unit a transport dimensions of 10-foot high by 8-foot-4-inches wide by 27-foot-11-inches long, able to fit on a lowboy trailer. The Komptech’s transport dimensions are similar at 10.7-foot high by 18-foot long by 9.8-inches wide while the Aeromaster can be fitted with an optional transport axle that makes it an easy to pull, trailer style, transportable attachment. The Terex unit at approximately 8.4-foot wide by 12-foot long and 11-foot high, is in the same ballpark as the larger units, but requires some disassembly and reassembly to transport.

Finally, operator comfort and safety considerations are as important as any other feature when buying a turner. Since the operator will be working in the turner on an hourly or daily basis, comfort, safety and automation features are a necessity. Does the operator have to climb a ladder or navigate catwalks to gain access to the cab or does the cab descend to ground level for safe entry and exit? Is the cabin filtered for gasses such as ammonia or diesel fumes while also providing air conditioning for added comfort during summer heat? Is there Bluetooth stereo and cell phone capability built in so the operator does not have to remove their hands from the controls? Are there automated control systems available that help the operator control the rate of speed and turning on the drum drive system to give optimum performance while turning the windrow? All of these are important and may or may not be standard equipment on the various units.

In addition to the drum-style turners mentioned in this article, there are also a number of other design choices and options on the market. These include additional pull-behind models, elevating face turners, lane turners for enclosed lane applications as well as accessory options for turner based water and/or inoculant applications, added operator comfort as well as lighting and custom drum choices depending on feed stock at the compost facility. Whatever the case, compost turners vary in size, shape and color, and the right one for you is out there!

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