Equipment used in composting applications can get really large. Some machines, such as Peterson Pacific Corp.’s 6700 grinders, have a footprint of 750 feet squared (63 feet by 11.9 feet). Other machines have really high capacities. The Scarab 27×11 A Frame windrow machine is capable of processing more than 15,000 tons per hour.
The Biggest Machines and Attachments Brown Bear
Brown Bear builds windrow aerators that are carried by a skid or compact track loader or farm tractor. These are powered by the hydraulics or tractor PTO output shaft of the carrier. These models aren’t self-contained or self-powered.
“We also build what we call a self-contained aerator for attachment to wheel or track loaders,” says Stan Brown, President, Brown Bear. ”These units have their own diesel power unit, hydrostatic system, fuel system, and radio control system to power the aerator rotor but need a wheel loader or track loader to carry them. We also build our own tractors with front aerator attachments. The Brown Bear unit provides the tractor and the aerator, all of which are driven by the Brown Bear Tractor engine.”
Brown continues, “Our largest unit is the Brown Bear 500C with 49-inch diameter by 14-foot-wide paddle aerator. The 500C is powered by a 350 hp Cat C9.3B Tier 4 diesel engine and will turn and aerate about 2,000 tons per hour.
Bandit manufactures a line of horizontal grinders in towable and track configurations ranging from 275 hp to 1,200 hp. Topping the range is the company’s Model 4680. It features a 45-inch-diameter capacity with its 45-inch-by-60-inch mill opening and the patented Bandit cuttermill. Equipped with 60 teeth, the cuttermill gives you the option of cutting, splitting, grinding, and chipping with the opportunity to mix and match cutting devices to allow for the production of uniform material with varying sizes. The cuttermill combined with the machine’s large dimensions allows it to process a wide array of materials and a production rate of about 800 yards per hour.
The largest windrow machine that Scarab manufactures is called the 27×11 A Frame; its tunnel is 27 feet wide at the base of the windrow and 11 feet from the top of the windrow to the bottom. The 750 hp machine has a cubic yard production—based on the material—of 15,100 cubic yards per hour; the tunnel width and height will compost 6.52 cubic yards per linear foot. A digital load controller is standard on all machines to ensure maximum power and fuel efficiency.
“In some areas, this size machine is important for the site. The site might not be able to expand out and the only way is up. The A-Frame accommodates those sites which cannot expand but are able to go higher to increase production with the same site,” says Richard Miller, Sales Manager, Scarab International. “When spec’d with a belt and gearbox drum drive, the horsepower to the drum is 98% more efficient than other drum systems. This equates to fuel savings, maintenance cost [savings], and labor cost savings. Less time in the windrow also increases productivity for the end result.”
Komptech also manufactures a line of mobile windrow machines. Their largest machine is called the Topturn X63. The 390 hp machine is approximately 20 feet wide by 14 feet long by 16 feet tall for the wheeled version and slightly smaller for the tracked version. It is capable of managing windrows with a base width of up to 8.5 feet and has a throughput of nearly 6,000 cubic yards per hour. The machine’s new cooling system keeps everything cool even under heavy loads and high outside temperatures.
Komptech also manufactures a line of mobile electrical drum screens called Cribus E; everything on the machines is driven electrically, from the hopper to the discharge belts. This minimizes the energy, wear, and servicing costs of the whole machine; it also features a newly developed direct drum drive. Controllable hopper and drum rotation speeds allow precise material alignment. Overfilling of the drum is prevented by load-dependent hopper control. The efficient cleaning brushes and uniquely generous clearance between drum and sidewalls prevent screen hole clogging, even with difficult materials.
The largest machine in the lineup is the Cribus 5000 E. It features 50 square meters of screening area, a 25.3-foot-long drum, and an 8-cubic-yard-capacity hopper for users who want high throughput with great screening results, especially with small hole sizes.
Both machines come available with the company’s telematics system—Connect!—a machine monitoring and communications technology. The Connect! hardware module is integrated into the machine and connected to the central control unit. Via a mobile radio (GPS data query by satellite), it reports to a central data server events and diagnosis codes, as well as data on operating hours, fuel consumption, idle time, and more.
“Peterson Corp has sold horizontal grinders, screens—both trommel and star, plastic and rock separators, and stacking conveyors for the compost industry. Peterson also sells blower trucks, which can be used to apply compost for erosion control projects, gardens, and more,” says Dave Girard, Recycling Market Development Manager, Peterson Corp.
The company’s 6700D (wheeled)/6710 (tracked) is their largest grinder. It is 63 feet long by 11.9 feet wide by 17.5 feet tall. Its hopper capacity is 11 cubic yards and its feed opening is 66 inches by 50 inches; this means the grinder can even process large stumps that used to be reserved for tub grinders. It’s powered by an 1125 hp Cat engine and is capable of production rates of 170 tons per hour for green waste and 111 tons for scrap board. “However, these production rates are based on 4-inch opening grades. Many companies in the compost industry would equip their machine with either a six-inch or eight-inch opening grates, so they could achieve even higher production rates.”
The Terra Select S60 star screen is the highest-production screen that the company sells. Peterson has the North American distribution rights to sell and service Terra Select products.
“The S60 is a high-production screen,” says Girard. “Star screens are perhaps the most productive portable screens on the market. They will handle wetter material better than a trommel screen and with easy adjustment of the star speeds, you can adjust your product sizing.”
The S60 is 43.7 feet long by 36 feet wide by 13.3 feet tall, has a 108 hp engine, and can process 106 tons per hour. The large hopper’s sloped feed walls prevent material from rolling back via the loading process. The feedstock is conveyed to a large dosing feed roll which separates the material before being fed into the top cartridge of stars.
“Roto-Mix has built its reputation as the leading manufacturer of livestock mixing and feeding equipment, as well as compost mixing equipment,” says Wally Stimpert, Manager of Government and Industrial Sales, Roto-Mix; for the composting market, the company manufactures horizontal rotary mixers, vertical mixers, and compost spreaders.
The vertical mixer is mainly used when you need to process one of your commodities down further. The vertical mixer is designed to cut material and handle large loads. For example, long hay or round bales can be processed in this machine.
The company’s largest vertical mixer model is the 1505. It provides 52 cubic yards of capacity and produces approximately 150 cubic yards per hour depending on material input and desired product. Dimensions for the mixer are 10.7 feet wide by 11.5 feet tall by 23 feet long. It weighs approximately 22,000 pounds, provides a maximum weight rating of 37,500 pounds, and has a 150 hp requirement as a stationary unit.
The company’s largest horizontal rotary mixer is the 920-18. It provides 34 cubic yards (920 cubic feet) capacity and produces approximately 136 cubic yards per hour depending on material input and desired product. Dimensions for the mixer are 9.9 feet wide by 8.5 feet wide tall by 19.3 feet long. The stationary unit weighs approximately 23,000 pounds and has a 120 hp requirement.
Roto-Mix’s line of compost spreaders and manure spreaders are available in truck or trailer configurations. The spreaders are available in bed lengths from 20 to 40 feet. Capacity ranges from 580 to 1,580 cubic feet. The box is 90 inches wide on the inside. “There are three different spreading attachments that affix to the spreader depending on the material being applied. There are vertical beaters, horizontal beaters, and compost spinners. Each attachment can be removed, and the box can then be used as a silage hauler or used to move bulk commodities. The unit is powered by the truck PTO or the PTO off of a tractor and horsepower requirements range with the size of the spreader and the choice of attachment. When spreading true compost, precision matters, and the Roto-Mix Spinner attachment offers just that,” says Stimpert.
Terex Ecotec manufactures a full line of shredders, recycling screens, waste handlers, windrow turners, tracked conveyors, and trommel screens. Their largest trommel screen is the Phoenix 3300. It is designed for unrivaled production throughput, as well as application flexibility. The machine’s flexibility is due to its many options, such as heavy-duty tipping grid or double-deck vibrating grid. The machine’s ability to perform equally well in heavy construction and demolition applications as it does in high-volume compost production adds to the machine’s versatility.
“The 3300 is the largest mobile trommel on the market, and because of that it offers the highest production rate of any trommel screen on the market,” says George Wilcox, Product Manager at Terex Ecotec. “It’s a big, heavy-duty machine that can handle a number of applications, such as wood waste, green waste, topsoil, compost, or mulch.”
With the 3300, you get a radial stacker with a 19-foot discharge height. “The radial stacker can adjust up and down, as well as rotate 180 degrees, so the operator, via remote control, can guide the stacker to create its own huge stockpile,” says Wilcox. “Therefore, this machine not only is the largest mobile trommel on the market, but it also provides the largest stockpile capacity. This is important when you’re handling high volumes of material because the material reaches the head pulley of the conveyor in no time.”
A powerful four-wheel drive system with high-performance friction wheels is used to turn the trommel drum, allowing it to be run bidirectionally. A standard Caterpillar 173 hp Tier 4 engine, combined with strong hydraulics, powers the machine. Phoenix trommels are also proven to be highly efficient in shingle applications.
Choosing the Right-Sized Equipment
“We size the machine according to how much product the customer is wanting or needing to process in a day and in a week and in a year,” says Stimpert.
“For years, Scarab has custom-built machines for specific customer sites,” says Miller. “Before designing the machine, we look at several specifications, such as how many tons per year they expect, the size of the lot, and how much production do you want. We estimate a compost facility will two to three times per week turn a product for six to eight weeks at 40–65 percent humidity and temperatures between 137 degrees and 165 degrees Fahrenheit in order to optimize the conditions for eliminating pathogens—what we like to call bad bugs. So, these are the three factors we use to determine what size machine a customer will need. This keeps us from making one too small or one too big for a particular site. That is one of the unique things about Scarab: we customize a machine to a customer’s site.”
“The customer should look at their production at an hourly rate. It’s important to look at the hourly rate because companies may not want to grind 10 hours per day,” says Girard. “Their operators may also be doing other jobs, such as loading trucks. So, it’s important to know the tonnage on an hourly rate and then pick a machine capable of that production and preferably choose a model that provides additional capacity for growth or to make up for lost production time.”
“There is a production rate figure on an hourly basis for each of our units and a maximum windrow size for each,” says Brown. “Once we know how much material there is to turn per day and we know the windrow size, we can select the appropriate turner.”
“When choosing the right sized equipment, customers need to look at the volume they need to produce on a daily basis and compare that to the cost of operating the equipment to make sure the venture will be profitable,” says Jason Morey, Sales Manager, Bandit Industries.
“The right size machine is selected based on a few different criteria, such as what the feed product is—the composition of it—the moisture level, what the finished product size is, what kind of market they’re serving, and the machine’s production rate help determine the screen area that is necessary to meet the requirements of the customer,” says Wilcox.
In order to offer more size options, Terex has introduced the new Phoenix 1600 trommel screen, which, according to Wilcox, meets the demand of many applications in the US. “The 1600 is a common Trommel size in North America, and this launch is actually the reintroduction of a machine that was previously under the Powerscreen brand; however, with it, we have taken the hallmarks and design standards of the 2100 and 3300 and scaled it back to what is optimal for the 1600,” says Wilcox.
“One other consideration when choosing the size of the machine is what machine is being used to feed the screen. For example, if you use a small backhoe to feed the screen, it can’t keep up with the production rate of a 3300. So, choose a machine that is similar to the rate of the machine feeding the screen,” says Wilcox.
The two biggest considerations when purchasing equipment for composting are the material input and the desired product.
“What kind of product do you want in the end?” asks Miller. “What are the size—the diameter—and the texture of your product? We build three different type drums to suit various desired products. We build a flail drum, which produces a chopping action, as well as turns the product. We produce an auger drum, which has lift and fluffing power—the auger drum aerates the compost; this drum type is popular on farms. And we build a combination drum for more chopping plus aeration.
For operations that require the application of chemicals or other additives to assist in the processing of the material, Scarab offers a basic spray system. The incremental introduction of the additives can be applied during the turning process rather than manually adding it at another time, thereby reducing the amount of time required and mixing the additives into the material instead of just applying it onto the top of the windrow.