Transforming Transfer Stations
Rather than merely being places to transfer trash from one vehicle to another, some transfer stations are becoming sorting stations
Transfer stations, which come in a variety of shapes and sizes, have traditionally served as consolidation points. They accept waste from collection vehicles, and workers then stuff the waste into trailers for transfer to landfills. Lately, some transfer stations have begun to operate more like their grownup cousins, MRFs, using a variety of picking and sorting equipment to pluck out recyclables from the wastestream.
In many transfer stations, stationary cranes are standard equipment, as they make quick work of moving waste from the dumping floor to the outbound trailers. For heavier C&D waste, especially steel that might be destined for a railroad car, cranes are indispensable.
“We had used compactors for years,” says Dick Malone, of Ocean City, MD’s solid waste authority. “But we made a change; we covered the compactors, made a push wall, and put in a 2100 self-contained Builtrite crane. We had the crane customized, so it wouldn’t hit our roof while in use.”
The model 2100-SE, manufactured by Two Harbors, MN’s Northshore Manufacturing Inc.(www.builtritehandlers.com) is designed for heavy-duty, day-to-day operations. Available in a multitude of configurations, it’s suited for a wide variety of applications and building layout specifications. Custom-designed configurations for this stationary electric crane include a remote operator station, a mobile operator station, a variety of cab heights for superior visibility, and a variety of attachments to suit various applications. One huge benefit of a stationary crane is that it allows operators to reach below grade for better trailer topping and tamping, whereas wheel loaders only push and lift material.
|Photo: Superior Tire
The Cushotrac Clamp-On requires no special fitting and is engineered to tighten directly to the steel double or triple-bar grouser shoe.
“We fill the outgoing trailers with the crane, and we usually have clean solid waste,” Malone explains. “This is a resort area, with no industry. The crane packs the waste very nicely in trucks, making it easy to get the complete 80,000-pound fill weight of the trailers.”
A crane run by electricity has definite advantages. “The Builtrite crane has given us very little trouble; it’s easy to work on—and with—this machine,” he says. “Plus, since it’s electric, there’s no diesel pollution inside the building. As we only have the one crane, it’s good that it doesn’t break down; it works all the time. In the five years we’ve owned it, we’ve maybe lost a half-day—and that was probably our fault; we didn’t think far enough ahead in our maintenance. But Northshore overnighted the part to us, and when we call them for help, we get the man who built the machine on the phone. He talks us through any repairs if we have problems.
“Oh, one problem we had to fix,” Malone chuckles. “Although the crane was customized, within the first week we had to modify our sprinkler systems. We’d taken into account the roof support clearance, but forgot to account for the sprinklers!”
There isn’t much that’s pulled from the wastestream. “We concentrate on pulling out tires, and big metal pieces,” Malone says. “If we get a piece of wood longer than 8 feet, we’ll break it up, or maybe reuse it. We send the rest to Covanta energy generation plants in northern Virginia and western Pennsylvania.
“I spent 23 years building this recycling facility—I owned it, then sold it to the city, and I ran it—but unfortunately, we just can’t justify spending more of the public’s money,” he explains. “It’s two-and-a-half times more expensive to recycle, so now we use our trash for energy generation.”
A Point of Diversion
“San Francisco diverts over 70% of its waste from the landfill,” says Bennie Anselmo, Recology Inc.’s vice president of equipment procurement and maintenance. “Recology provides 18 separate and distinct reuse and recycling programs in San Francisco, more than any other city in the US. We don’t go through trash to look for recyclable items; residents sort their trash at home. For residential collection, we use split trucks, which collect both trash and recyclables, in one pass. Greenwaste is collected with another truck.”
C&D waste gets sorted at the transfer station, he says: “We have sorting lines, where we pull off cardboard, metal, plasterboard, hard plastics—all that’s pulled off to be recycled. We’ve had to add more square footage to our building for the C&D processing. Residential/commercial trash goes to another transfer station. We’ll run magnets through that, to catch any stray steel cans for recycling.”
Recology uses Caterpillar vehicles in its transfer station (www.cat.com). “We operate two D8 Cat dozers inside the transfer station pit,” Anselmo says. “For the C&D sorter, we use 938 Cat loaders to load onto the sort line. These machines feature a four-in-one bucket arm, and are equipped with magnets to get small metals. Any really big stuff is pulled out by hand.”
Why did Recology choose Cat? “Cat has been the primary provider for earthmoving and transfer stations because of its reliability,” Anselmo explains.
“We bought machines specifically built for our industry with air filtration, guarding systems, and radiator systems adapted for solid waste use. Since there are many sharp and broken objects in trash, we’ve been using solid rubber tires for 10 years.”
Although its products are quite familiar in earth-moving projects, Peoria, IL’s Caterpillar has also committed itself to MSW machines. “Due to the breadth of our product line, we can serve any size operation,” says Bill DeBord, Caterpillar market professional. “We produce medium and large wheel loaders and skid-steer machines, which are frequently used to pull out paper, cardboard, et cetera, as well as for compacting waste for hauling vehicles and railroad cars. All equipment is diesel powered, but they have low emissions, which is especially important for inside work. Electric-drive and hybrid models will become more common in coming years. Track- and wheel-excavators and backhoe loaders are also frequently used in MSW applications.
All of these are available in special “waste arrangement” packages, according to DeBord. “You have to protect the operator as well as the machine,” he says. “Cabs have special guardings, such as shatterproof glass. Waste machines also have heat-exchange packages, wider spacing in the radiator, so debris blows through, to keep radiators clear. Trash is considerably worse for overheating problems than is moving dirt, because the work usually happens indoors, in a confined environment. Waste operations may have also misting systems, to keep dust down; of course, then, dust particles will cling to things that are slightly wet. But on radiator, that moist dust dries, and you’ll get a ‘crust.’ A reversing fan mounted near the radiator blows that stuff off before it can dry. This works for the heat-exchange radiator cores and air-conditioning unit, as well. We made it easy to access; operators can just open it and blow it out. We discourage high-pressure water for this, however, as dust will start clinging again. Maybe one could water clean the unit at the end of the work day, so it has time to dry overnight.”
DeBord theorizes that many customers are doing more with their transfer stations. “In the past, transfer stations were built because it was more economical to have transfer stations, and 18-wheelers taking trash to the landfill, than having garbage trucks shuttling back and forth to the site. Now, perhaps 50% are doing something else than just transfer. Maybe they’re pulling out yardwaste, recycling items that may have gone into regular trash.”
For customers to get the best use from their machines, Cat sponsors training. “A fair amount of machine applications training goes with this, through our dealers,” he says. “Customers are taught how the machines work in particular waste applications, what you’d have to equip the machine with, et cetera. We make a complete line of work tools to go with the machines, such as grapples and specialty buckets. These tools are added via a fusion coupler, which makes it easy to switch out from one tool to another.”
Cat is now selling solid rubber tires. “We’re always looking to see what the customers need,” DeBord says. “At first we used mining rock tires on our waste-hauling machines. Over time, the tire choices evolved, as even those didn’t have a long life in a transfer station. For one thing, transfer stations are wet, from dust misting and foodstuffs, and then you can have abrasive material. Add to that the typical ramps, inclines or declines, and spinning tires—that wears tires down.”
Other manufacturers offer a “middle ground:” foam-filled tires. “That’s a variation of a solid rubber tire. Yes, it costs less, but when it does wear, a chunk of it can come off, and perhaps fly off and injure someone,” DeBord says. “Solid rubber tires mean no punctures. The life of these tires varies; some transfer stations go through them in six months. As these tires give machines and drivers a rough ride, we have ‘Flexport’ tires, which are solid rubber containing elliptical holes that ‘squish out’ and become round, acting like shock absorbers.”
With so many machines out there, how can one choose? “We publish a machine selection guide, which helps people select the right one,” DeBord says. “As customers read through it, they can match what tasks they have to perform, at what kind of facility, to which machine to buy.
“A lot of features on waste-handling machines, can’t be seen with the naked eye—they’re internal ‘tweaks’ that protect the machine from its environment. People might look at machines and wonder why to buy one over the other, when the waste one is more expensive—well, pay us now or pay us later—the unmodified machines will have more problems and need repairs,” he concludes.
A transfer station places heavy demands on equipment.
Making Sure the Job Doesn’t Stink
From the bag or cart you lug to the curb, all the way to the landfill—waste often has a bad odor. The closer a transfer station is to populated areas, the more odor becomes a concern.
“It’s important to control odors, to keep neighbors and everyone happy,” says Rick Johns, district manager of Elgin, IL’s Bluff City Transfer, which is owned by Waste Management Inc. The facility, which accepts refuse from a 20-mile radius, opened in 2007 and is located in a former gravel pit that is being reclaimed as an industrial park.
Some recycling is done there. “Recycling is dumped in a designated area from residential collection, put in larger trucks, and taken to a sorting facility,” Johns says. “We use four-wheeled endloaders to work the pit, and load the larger trucks with excavators. As for odor control, we use OMI model 450 CFM vapor units for the tipping area. The scent smells good; you can’t really smell it on the tipping floor, but you can when you put the scent into the vapor machine. The OMI piping is secured to the ceiling, and the apparatus creates a very fine mist on the tipping floor. The transfer station is a covered facility, confined—but we don’t get a lot of dust, since we have exhaust fans.
“We’ve used OMI’s odor control from day one, so I don’t know that we’ve had any complaints. The system is on a timer that runs during our business hours. At the end of the day, the tipping floor is totally clean, so there’s nothing there to produce odors overnight.”
Odor is just one facet of its operation that Bluff City Transfer keeps under strict control. “Waste Management, which owns the facility, is an industry leader in waste collection and environmental cleanup,” Johns says. “We’re disciplined on how we run our operations; we consistently look at loads, keep our facilities clean, try to be a good neighbor. We always put safety first and strive to be a trusted community partner, giving back to the areas we serve. We’re also a model facility—LEED gold-certified—with a green roof. We recover rainwater from our vegetated roof and channel that rainwater to a cistern, which we use to flush toilets.”
Tom Minett, national sales director of Barrington, IL’s OMI Industries, offers a bit more background on the company’s products. “Ecosorb odor eliminator doesn’t mask smells, it neutralizes them, by breaking down and removing a broad spectrum of organic and inorganic odors,” he says. “Our product has been specced into a few transfer stations in this area. Ecosorb is liquid-based; when used in the 450 CFM Vapor Phase equipment, it’s made into submicron-size droplets without using any water. This is how we get into new buildings/operations, because many firms want LEED certification—and ‘not using a lot of water’ is a LEED principle. The product is only for odor control, not dust control. If dust control is also needed, facilities have to use water. In those cases, a high-pressure atomization system is used, and we inject our concentrated Ecosorb product into that water. As the Ecosorb is neutralizing odors, our product helps the air quality for people working there, which is also a LEED principle.”
OMI has been serving industries for two decades, Minett says, and now the company is branching out: “We’ve taken what we have learned from our industrial customers, and applied them to a new line of products named Fresh Wave, for retail sales. The product has all the active ingredients as the industrial formulation, a proprietary mix of plant oils, which makes odors ‘disappear,’ with no replacement odors. We have also taken our formulation and make it into an oil-based additive that can even make asphalt plants ‘disappear,’ so there shouldn’t be anything in an average American home that would defeat it.”
One Person’s Trash Is Another’s Energy Treasure
Although Miami, FL’s Covanta Dade Renewable Energy doesn’t operate transfer stations per se, it does do a certain amount of sorting on its tipping floor.
“We don’t control any transfer stations,” reports Business Manager Bill Meredith. “Miami-Dade County operates three transfer stations and two landfills, which are also used to transfer waste to our facility. WSI and Waste Management also operate transfer stations in Miami-Dade County, so we don’t have to do much sorting when residential waste comes in. Trash comes to us in curbside trucks, or 18-wheelers. We have two tipping floors—one for MSW, and one for greenwaste. Our preshredder sorting, which is mostly minimal, entails magnets pulling any ferrous materials out.”
Moving refuse to various areas of the site’s tipping floor is done with Volvo loaders. “When trucks do their tipping, if they miss the pit, the loaders will move the material to where it belongs. If there are any contaminants in the greenwaste, the operators will pull that out. Once a year, Miami-Dade County has single-source recycling, and it does a good job of sorting, but when the area has bulky-waste collection—furniture, et cetera—people can bring anything to us. That’s when we can get some odd stuff that needs to be pulled out. We take out non-process materials that won’t go in shredders, and put them onto a conveyor, for some manual sorting and separate them before they get to the shredder.”
This waste-to-energy plant and a biomass facility, owned by Miami-Dade County, is operated under a long-term agreement by Covanta. “A small portion, 10% to 13%, of yardwaste is burned,” Meredith says. “The rest becomes biomass, and is exported to other facilities to make energy.
“We make RDF—refuse-derived fuel. We put trash in shredders to make smaller, more consistent, easier-to-burn particles. First, bag rippers open the residential bags; if some recyclables have made it to our plant, we take them out and recycle the items. Ferrous is removed prior to incineration. Barring that, whatever’s thrown in gets burned, and everything burns—at least, about 80% of the MSW. No matter what’s being burned, scrubbers and baghouses ensure that we are below our EPA-mandated emission levels. What’s left over might be small pieces of glass, rock, and sand, which the county takes back, to use for daily cover on its landfill. The rest is ash, which goes to an ash monofill landfill. Magnets are used at the end of the process also, just in case we missed ferrous material. We also use eddy-current separators to remove aluminum or nonferrous materials.”
“We’re reducing the volume of the waste by 90%,” Meredith goes on. “Plus, we’re creating electricity for about 50,000 homes. Florida Power & Light transmits the electricity to Progress Energy, which buys our plant’s electricity. The revenue is split 50-50 with the county.”
“Our wheel loaders and excavators are used in the waste industry,” says Blaine Pressley, segment director for Asheville, NC’s Volvo Construction Equipment. “We help customers decide what size they need by looking at their peak loads, their building’s ceiling height, their workload, and total production.”
Pressley explains a transfer station’s usual tasks and traffic. “Maybe you need to stockpile waste, because a lot comes in at one time,” he says. “You also need to pack it in, so it doesn’t escape. When 18-wheelers drive into the pit and are filled, it’s the wheel loaders that push trash into the trailer. Recycling facilities might only need to use compact wheel loaders.
“A waste-moving wheel loader is a totally different animal from one, say, in a quarry operation,” he goes on. “Our ‘transfer station package’ machines have belly guards underneath, where in a ‘normal’ application, that area would be open. Waste wheel loaders’ hydraulic hoses are spiral-wrapped in steel, with extra protection for the cab, the engine, the radiator. The radiator, for example, has reversing fan; it will run in the regular direction for 30 minutes, then for three minutes run backwards to clear debris. Many damaging items can be on the floor of a waste facility—cables, rock, glass—and the vehicle’s axles have seal guards, which ensure that wire doesn’t get in and wrap around, ruining the axles. Any ‘basic’ wheel loader will break down in short amount of time if it doesn’t have this package on it.”
Where the rubber hits the road, it’s solid. “The package includes solid rubber tires, meaning no punctures—and although they might experience cuts, they keep running. The operator seats all have suspension systems, because you do get a rougher ride in solid rubber tires.”
Volvo, a famously Swedish company, also builds its heavy machines in Brazil. “We’re a preferred product in the waste industry,” Pressley concludes. “Some sites also like using excavators, because they can turn 360 degrees, but more people are just using the wheel loader, because it can do so much, and that means having less equipment on site. However, some transfer stations have walls, and step patterns—meaning lifting over obstacles—and those would need a excavator.” MSW
Author's Bio: Janis Keating is a frequent contributor to Forester Media, Inc. publications.