BioCycle April 2006, Vol. 47, No. 4, p. 20
Facility operators find that transport trailers with moving floors are the most versatile when handling a wide range of feedstocks and end products.
THE organics recycling industry deals with a lot of variability in the raw materials and finished products handled – from wet sludges and mixed loads of wood debris, to small particle size compost blends and coarser mulches. For small compost and mulch production operations, dump trailers can suffice for product delivery in most cases. But as soon as volumes increase – either incoming or outgoing – transport efficiencies become paramount. And in many cases, the need gets resolved with live bottom trailers, which offer both adequate capacity and self-unloading at reasonable speeds.
Generally speaking, the live bottom trailers being used in the organics recycling industry fall into two categories: continuous belt floor systems and slatted, live floors (also referred to as “shuffle” floors). Trailers come in a range of capacities. The bodies are made of aluminum, steel or fiberglass reinforced plywood. The walls and floor can be coated with plastic, which reduces adherence of particles and accelerates unloading. The belts in conveyor floors are sold in a variety of widths. With the wider belts, the walls taper to meet the edges of the belt. With the slatted floors, the whole bottom moves; the sidewalls are vertical to the floors.
While one style of floor may be better than another for some specific materials, what has become evident over the years after talking with many truck owners is that both styles are versatile enough to handle both raw materials and finished products. Essentially, it seems to boil down to a matter of preference. Some operations own fleets of slatted floor trailers while others buy nothing but belt floors.
ROYAL OAK FARM
Royal Oak Farm, LLC in Evington, Virginia is an agricultural composting operation that is in the process of upgrading from a “permit-by-rule” status to a solid waste facility so it can handle greater volumes and varieties of commercial and industrial organics. Currently, Royal Oak composts hog and chicken manure, wood ash, sawdust, tree stumps, brush and some agricultural feed waste. It also receives paper mill and food processing by-products. “We haul a wide range of materials, including animal feed, compost, mulch, topsoils, chicken litter, sand and stone,” says Ken Newman of Royal Oak. “We have a fleet of belt floor trailers from Trinity Trailer, including a couple with 90 cubic yard (cy) capacity that have fold-down doors on the side and swinging tail gates. We recently bought a new trailer designed for hauling compost, topsoil and any kind of sludge. It has about 60 cy capacity, hydraulic doors, and a 42-inch wide belt. All of our trailers are stainless steel.”
Newman likes the belt trailers for their speed of unloading, and the versatility in terms of the range of materials that can be hauled in them. And he much prefers live floors over dump trailers due to their stability when unloading. “We ended up in some situations, whether it was at a farm, a landscape yard or even a municipal site where a dump trailer was used and a driver tipped it over. In fact, I don’t know anyone who runs a dump trailer that hasn’t tipped them over once or twice. And with wind conditions, you have to be on really level areas. That just isn’t an issue with the belt trailers.”
Once Royal Oak gets its new permit, it will start collecting food residuals. It plans to use rolloff trucks with 30 cy sealed containers. For some sludges, Newman notes they will use 3,500 gallon tankers mounted on skids with a hook lift system. “Basically, we will drop those off at the plants and they can pump directly into the tankers. Then we will load them back on the truck to haul back here.” He adds that the upgraded site will have a 12-acre paved area for windrow composting. Royal Oak Farm owns a Backhus turner, as well as a Doppstadt trommel screen. It plans to purchase a slow-speed shredder to produce its own bulking agent for the wet feedstocks it will be composting. “The wood ash, manure and paper mill sludge are dense, heavy and/or very fine particle material so we need to get porosity into the windrows,” explains Newman. “Around this area, we have to buy quality woodchips because there are three paper mills, a particle board plant and a wood-fired electric power generator – all of which use the wood waste available in their boilers. The shredder can be used for stumps and brush – which we get paid to take – that have a lot of soil on them and could mess up high-speed grinding equipment. The shredder will give us a coarse chip that we can recover after composting and cycle back into the process about four or five times.”
For almost 30 years, Reuser Inc. in Cloverdale, California has been turning redwood bark, chips and waste wood from sawmills into a range of soil amendment products. “We move close to one million cubic yards/year,” says John Reuser. The company’s processing system includes stationary grinders and trommel screens, which are used both before grinding for presorting feedstocks and after grinding for particle sizing. Reuser produces about 100 different types of mulches, including the colored varieties (it owns a WizTech foam coloring system). No green waste is processed at the Cloverdale facility, or a second site in Ukiah, about 30 miles from Cloverdale.
Reuser Inc.’s trucking fleet includes about a dozen trailers with the Keith Walking Floor system installed. Keith floors use a 4-stage cycle to load or unload the trailers. In each of the first three stages, a third of the slats move forward while the other two-thirds are stationary. In the fourth stage, all slats move to the rear of the trailer, moving the load with them. “The average unloading time is about 7.5 minutes,” says Reuser. “We typically haul an average of 145 cy in a load. Sometimes, if materials are wet due to the weather, we can’t get quite as much on the truck.”
He adds that the company prefers the slatted floor system over the belt trailer for many of its materials because of the capacity of the trailer. “We deal in lighter materials so we can get more in a walking floor than a belt trailer. With the latter, the bottom half angles down and you lose capacity. However, we are evaluating a belt floor model for hauling rocks.”
SWANSON BARK & WOOD PRODUCTS
Swanson Bark & Wood Products in Longview, Washington started out in 1928 as a wood fuel company. In 1994, the company was sold to John Leber, who changed the name to Swanson Bark & Wood Products, Inc. to reflect the range of the company’s product line. During the mid-1990s, Swanson initiated an urban wood program that placed drop boxes at sawmills, cabinet shops, and construction sites. The collected material is sold as fuel, firewood or processed and marketed to pressboard and particleboard manufacturers as furnish. A number of grinders are used at the yard in Longview, including four stationary units and portable grinders from Peterson and Morbark.
Not long after Leber bought the company, he began investing in live floor trailers to make off-loading of materials easier. “Today, we have 31 live ‘shuffle’ floor trailers, all equipped with Hallco Manufacturing Co. floors,” says Leber. “We do have one belt trailer in the fleet. We have found that while the belt unloads faster, you give up volume of the load. And if the load isn’t balanced, it won’t move forward. In addition, if we make a delivery and want to back haul pallets, we can only do that with a shuffle floor.”
Swanson’s product line gradually expanded to include a wide range of rock, soil mixtures, landscaping materials, and gardening accessories, as well as 12 different types of bark. In 1997, a bagging plant that allows Swanson to package custom soil mixes and bark grinds for wholesale clients was added. The company uses a lot of compost in its product mixes, but does not have its own composting facility at its processing yard.
WOOD WASTE MANAGEMENT
Wood Waste Management, LLC, and two sister companies, American Compost and Recycling, LLC and Clackamas Compost Products, LLC, are all located in the Portland, Oregon metropolitan region. Wood Waste Management receives clean wood, sod, brush and yard trimmings. It also has a retail yard for landscapers and other customers. The wood is ground at that facility, and the green waste and grass are hauled to either American Compost or Clackamas Compost for composting. The ground wood is hauled from Portland to a boiler fuel facility in Washington State.
Belt floor trailers, manufactured by Trinity Trailer, are used exclusively by the companies, says Rick Franklin with Wood Waste Management. “We can unload a 135 cy load in two to three minutes, which is why we prefer belt trailers over the shuffle floors. These units are very durable. We just had a small belt trailer rebuilt for the first time after it was in continuous service for six years.”