|
|
|
Feature
Article July/August 2000
|
|
You
may print one copy of this page for personal use. Please report any
other use to FORESTER COMMUNICATIONS, INC., using the online form at
http://216.55.25.242/crv_report.html
|
|
By paying
attention to each facet of a waste-disposal operation and choosing the
right equipment, a MRF or transfer station can be a more harmonious -
and more cost-effective - enterprise.
By Joseph Lynn Tilton Profitable
Recycling Operation
When it comes to waste disposal, the challenges are never-ending. Starting right at the curbside, they don’t seem to cease even when the material has been shipped to its final resting place. Yet operators at any point can rejoice when things go well. Or as one person says in reference to his city’s recycling and transfer station, "It’s poetry in motion." That’s Grant Dunne, management analyst for the City of Oxnard, CA, talking. He’s been with this coastal city of more than 150,000 people, some 60 mi. north of Los Angeles, for the past 10 years. But the poetry in motion in the city’s waste-disposal activity is the Del Norte Regional Recycling and Transfer Station, which opened in the southeast part of the city in August 1996. "It’s on 16.5 acres and takes in about 1,200 to 1,400 tons of waste and recyclable material a day," Dunne explains. "The transfer complex also has a materials recovery facility (MRF), so it’s a two-component operation." There are nearly 100 employees on the site. Dunne adds that while the city owns the facilities and the equipment involved, the operation itself is contracted out. "We believe a private contractor with experience in running MRF and transfer station operations can be more efficient at running the facility. In addition, this arrangement gives the city a way to market recovered materials in the private sector using private contracts." Profitable Recycling Operation Dunne explains that the city’s recyclable curbside materials are source-separated into cardboard, aluminum, newspaper, and plastic. "We share with the facility operator in the sale of recovered materials. This gives both parties incentives to recycle, to divert and market the goods in order to receive as much income as possible. On average, together we gross about $500,000 per month from the sale of recovered materials." Net profit for the city is about $100,000 per month. Furthermore, it has been profitable almost from start-up. "We haven’t had any prolonged experience in marketing costs being more than the revenue generated. There’s been a net share every month, and that share has been a big help in stabilizing collection rates in the city for residential and commercial customers."
The City of Oxnard has 47 refuse collection trucks handling residential, commercial, and industrial pick-up needs. Those vehicles enter the 48,432-ft.2 waste floor at the Del Norte Regional Recycling and Transfer Station, dump their loads, and get back out on the streets. At the MRF line, sorters pick through the curbside recycling mix to separate cardboard, paper, aluminum, glass, and plastic. Tractor-trailers are used to haul the actual waste to one of three landfills. Two are 20 mi. away; the third is 30 mi. away. "By taking waste to three landfills instead of contracting with just one, we have flexibility in our hauling options. This arrangement also helps encourage greater competition among those landfill operators, which helps keep ultimate disposal costs down." Dunne adds that the operation uses Kenworth T800 tractors and Peerless RTSSF-48 trailers. "We have 15 units, and each is able to haul four to five loads a day. A couple of the landfills don’t have trailer-tipping facilities, so we went with the Peerless Keith Walking Floor models. Also, by being able to dispose without landfill help, there’s no waiting in line to use a trailer tipper." Don Hepperle, sales engineer for Keith Manufacturing in Madras, OR, points out that over the past years, walking floor-equipped trailers have become 3,00-5,000 lb. lighter, providing increased payload capacity. "Reducing the amount of moving parts has made it even simpler to unload. There’s no need for a heavy chain drag, push ram, or trailer-tipping operation." As with anything else with moving parts, care has to be taken to avoid possible jamming or damage. This is why the site does not take construction waste, such as large pieces of concrete. "We have to be careful about what we put in these trailers as far as concrete, rocks, and any large objects go that may catch in the walking floor. The operator here is careful to look at the waste from a bird’s-eye view and communicate with sorters and waste pushers about what they’re moving in as they top-load the trailers," Hepperle points out. As a result of this care, no expensive problems have occurred in four years of operation. "We have no real consistent problems," he notes. "We make sure our trailers are covered, and when top loading, we make sure we’re not loading bulky refuse that has the potential to puncture trailer walls. A lot of effort is used to maintain a smoothly running operation. Once in a while there will be a hauling incident in which the tractor-trailer has stalled and we have to get crews out there immediately to clean up any mess. We have service agreements with companies to fix a down machine right on the roadway. But if it can’t be repaired there, the service agreement provides for immediate towing to a garage. "To run an efficient operation, one has to be vigilant and use service agreements, mechanical service agreements, and other means for immediately resolving problems. Then when problems do arise, one is covered."
Dunne reports that it takes just five to 10 minutes to load a trailer to the 80,000-lb. legal limit. "The vehicle enters a tunnel underneath the unloading floor. The transfer trailer rests on a scale while two Cat 940F and one Cat 950G wheel loaders push the refuse into the open portal, where it drops loosely into the transfer trailer. The waste loader can tap the refuse to give it some compaction. Then, when they reach the weight limit, it’s ready to go. I call this ‘poetry in motion.’" The site also has two Bobcat 1845C skid-steer loaders that handle the recycled material, as well as five CAT GP25 forklifts, overhead storage toppers for various recyclable commodities, and an American Lincoln 3366XP street sweeper that sweeps in and around the facility. A Mack rolloff truck moves bales and other recyclable goods in and around the facility. "Those skid-steers are used in tight areas, but when they need help, we can send over one of our wheel loaders, and visa versa." Both the skid-steer and wheel loaders help maximize efficiency because they provide flexibility in dealing with immediate, short-term needs. This arrangement ensures maximum use of each piece of equipment and a minimum of idle time. Looking toward the future, Dunne notes that the site has room for expansion. "We’re permitted to do 2,700 tons per day, which is about double our present volume. Our building covers 119,595 square feet, so when we get to 2,500 tons per day, then we’ll look to expand the site to add room for the incoming tons. As it is, we have lots of room yet."
When it comes to moving waste or recyclables, wheel loaders have the volume, while skid-steers offer the maneuverability. "Waste transfer stations need machines that can stockpile, have adequate bucket capacity, and load quickly," stresses Sam Wyant, wheel-loader product manager for New Holland Construction in Carol Stream, IL. "The main objective of the wheel loader in the transfer station is to separate and load refuse. You are moving the material from lower-capacity garbage trucks to higher-capacity transfer units, most commonly trailers. In many applications, the wheel loader will be the main production machine, while the skid-steer will add-in site maintenance. They may perform a complementary role." Wyant notes that when shopping for wheel loaders, the machine will need to be matched properly with the site. "The leading concerns include average daily volumes, operating area, and load or target height. Transfer stations can tend to be a tight operating environment, so make sure the machine is sized properly for the application." He recalls a transfer station in Ohio that had a machine too large for its site. "Due to corporate downsizing, the site ended up with a 7-yard machine that was just too big. When management purchased a 5-yard machine, they were able to increase efficiency and maintain productivity. The machine also fit the site better, which helped reduce the possibility of onsite mishaps." "Additionally," Wyant notes, "you need to consider the choice of high-maintenance items, such as tires. A transfer station tends to be a rough environment. Foam-filled tires, for example, can alleviate the threat of puncture but will jeopardize the suspension that tires have. There are some materials on the market that can give you the advantage of foam fill and suspension, so you should check them out." Other features that make the operator more comfortable and productive can include a load travel stabilizer system, an enclosed cab with air conditioning, adjustable seats with air-ride suspension, and ergonomically placed operator controls for ease of operation.
"When transferring loads, you want to maintain speed and stability," emphasizes Kent Pellegrini, skid-steer marketing manager and attachment product manager for New Holland Construction. "If the skid-steer doesn’t have good balance, it won’t perform well. Transfer stations all over North America have many different loading conditions, such as rough terrain, bumps, and flat areas. Even with just 100 yards to travel, a two-speed machine can help maximize productivity. The operator can go into the pile in low range, then return in high range to the waiting vehicle." In addition, a stable machine won’t fall forward with a loaded bucket when going over a hump in the terrain. Ideally, the machine should be able to load a truck from either side. Also, with a skid-steer, the operator can pull material out of a 45° hole.
Pellegrini advises the potential user to decide whether he needs hand controls or foot controls. Noting that his company offers 70 attachments, he comments, "The skid-steer can be a really versatile machine. All you have to do is add a blade, and it’s ideal for pushing material. Switching from bucket to blade should take less than a minute." Another desirable feature is the ability to tip a bucket forward the way a wheel loader does. This can save the operator money. For example, when buying a 72-in., 4x1, 11.9-ft.3 bucket that opens from the bottom, the cost can be $2,500 versus about $900 for a dump bucket. Yet another consideration is serviceability. "Tilting cabs takes time," Pellegrini says. "With our machines, owners can pull the engines and get to all the major drive components without having to tilt the cab." The seat pops up, allowing access to the hydraulics. Further, an advance warning system monitors all critical functions. If the oil temperature gets to a critical high, the machine will automatically shut down. This helps keep major failures to a minimum. Lynn Roesler, Bobcat skid-steer-loader product manager, agrees that there are many considerations are involved when purchasing a skid-steer. "Look at the whole package," he advises. This includes the product’s reputation for reliability and durability, the range and availability of attachments, and the dealer’s ability to support with readily available parts and knowledgeable technicians. "When looking to purchase a skid-steer loader, buyers should consider several factors, including size, versatility, performance, comfort and convenience, serviceability, and durability." Dumping height and reach are again a concern, as is the variety of tasks awaiting the machine, which can range from digging trenches to sweeping the facility as well as raking and tilling the transfer station or MRF landscape. Operators also need to determine whether maneuverability or smoothness of the ride is of prime importance. Shorter-based loaders can turn a tighter radius, while those with longer wheelbases provide a smoother ride. Recent improvements in skid-steer-loader design have also translated into more operator-friendly equipment. To enhance operator comfort, some skid-steer-loader manufacturers offer a variety of optional cab features. These include full-suspension seats that adjust to the operator’s weight and size; larger front openings for easier entry and exit; windows that can be easily removed for cleaning; advanced, ergonomically designed hand controls; heating and air-conditioning systems; and deluxe instrumentation packages to help operators easily monitor loader functions.
When it comes to efficiency, the smaller the operation, the bigger the challenge. Yet such operations can be more effective and more efficient. Take, for example, Columbia County, WI’s solid waste operation for 45,000 residents. This site began recycling in earnest some 19 years ago, and this year it added a leaf-composting operation to the complex. "Our recycling program gives us $20,000 a month in sales," states Solid Waste Director Bill Casey, who has been with the operation for 17 years. He reports that the site handles 65 tpd of compostable material and 25 tpd of recyclables. The 16 workers on this site are capable of handling a combined total of 100 tpd. "About a third of the total that comes in goes to the landfill about 65 miles away, and that is handled by a private contractor."
Columbia County has a presort program, so only three sorters are needed on-site to ensure proper disposition of newsprint, plastics, tin, aluminum, and brown, clear, and green glass. They also take appliances and have a sharps program for people in need of hypodermic syringes. "We also have a tire and oil recycling program, but paper and cardboard are the two biggest," Casey adds. Naturally, the more complex an operation is, regardless of size, the more equipment is needed to ensure efficient flow of recyclables and waste. Columbia County’s onsite equipment includes four skid-steer loaders: two Case 1845s, one Case 1825, and one Bobcat 773. "We also have two wheel loaders - a John Deere 624 and a New Holland Construction LW 50 - as well as a Scarab windrow pile turner for the composting operation." Two forklifts - a Clark and a Mitsubishi - round out the equipment lineup. The conveyor systems in operation include a Mayfran for the sorting area. "The sorting line is 50 feet long, with an incline conveyor that’s another 50 feet. The baler feeder uses another 50 feet of this 40-inch-wide system," describes Casey, adding that their tin-sorting operation uses a 20-in. Prodiva conveyor, again about 50 ft. long. "We have another 300 feet of system for the composting operation." Weather can be another challenge, with temperatures dropping to -40°F in the winter and hitting 105°F in the summer. "Most of the work is indoors, so rain or snow is not a problem," says Casey. "Our five buildings have a total of 96,000 square feet. "We’re always looking for new markets for our recyclables," Casey states. "We’re also looking for ways to improve the composting operation."
"Our Keith Walking Floor slabs, which can measure 9 feet wide by 40 feet long, function as the initial feed point for our conveyor systems," reports Marty Mitchell, off-road and facility manager for Taormina Industries in Anaheim, CA. This company has waste-disposal contracts with several cities in southern California, and the conveyor systems are important elements in its operations. Keith Manufacturing’s Hepperle comments that his company’s onsite Walking Floor conveyors help automate the system used, whether the site uses compaction, precompaction, or direct dump into a trailer. "These floors can dump directly into the waiting trailer, or they can be used for helping to sort materials. But source separation is a real help. I know of a California facility with 95% recovery because of source separation. Those who typically take in whatever is available tend to have an 18-35% recovery rate. "Recycling is expensive, but the more material a MRF can put through, the more economical the operation - and the greater the community benefits. New York used to generate 18,000-20,000 tons of garbage a day. Now it’s shipping 13,000 tons a day because the rest is being recycled." And conveyor systems are part of that effort. Looking at conveyor systems, Mitchell counsels, "Durability is a major factor. You need to keep the system simple, with the fewest maintenance problems possible. The electrical controls need to be durable enough to handle the dust, dirt, and moisture brought to the site by the materials." He adds that some of Taormina’s belts are up to 84 in. wide and up to 80 ft. long. "The incoming stream dictates how big and how wide those belts need to be. Ours can handle a wide range of presorted products as well as trash itself, which can end up in a barge, a railcar, or a trailer for shipment." Mitchell points out that California law requires a minimum of 50% recycling of the wastestream, while some cities have even higher specs. "Properly sized conveyor systems help us to be efficient and effective with minimum downtime problems." His particular site, the CVT Recycling and Transfer Station in northeast Anaheim, is permitted for 6,000 tpd and has been operating since 1984. "We schedule our preventive-maintenance time so there’s minimal interruption to what is essentially a 24-hour-a-day operation to ensure maximum efficiency. "There will be more automation, and end products will be even cleaner before they’re sold to those who utilize recycled materials. Improved technology helps make possible the higher sale prices on recyclable products because buyers will spend less time getting that material ready for remanufacturing." More and more, waste will become an income-producing opportunity instead of a drain on community or county resources.
"The most important thing is to spec the trailer for the operation," says Mark Sabol, product manager of solid waste equipment for East Manufacturing Corporation in Randolph, OH. "Each operation might have a different application needed to work that operation. For example, in top loading, a strong top rail helps keep the sides from bowing and the top from being damaged. Deep cross-members provide resistance to bending when the initial onslaught of trash is dropped into the trailer from the top of the tipping floor." Rear-loading trailers need to be strong enough to accept the pressure of precompacted garbage being loaded. "Is the trailer being utilized as a receiver box or as a carrying vessel of a precompacted load?" asks Sabol. "Basically, with a carrying-vessel type, you can have premature failure in a compactor application because the trailer might not be set up to work in that fashion. Damages could range from perforated side sheets to weld or rivet failure, which certainly could render the trailer unusable." Offloading is determined by the landfill itself. "If they don’t have a tipping operation, then you have to have a walking floor - or be prepared to shovel out the load. The older ejector push-out trailers were heavy and weren’t economical, which is why you don’t see much of this technology in new trailers today," Sabol concludes. The work with trailers is finding durable models with minimum actual weight, whether in a live floor or one that will be tilted when it reaches the landfill. Jack Pieri, regional sales manager for Peerless Corporation in Upland, CA, points out that his company has been manufacturing transfer trailers and landfill tippers for 25 years. "A tipper lifts the entire trailer up to a 65% angle to dump, which takes about four minutes. This sounds ideal, until you add in the connect and disconnect time, which can add a lot of time. A live-floor trailer, on the other hand, can unload in six to eight minutes and immediately be on its way. Further, there’s no waiting your turn to use the tipper, if the site has one." Pieri notes that today’s aluminum trailers are 25-30% lighter than their older-model steel counterparts, which results in much more actual legal payload. "The industry has gone to aluminum bottom rails, aluminum cross-members, aluminum hubs and centrifuge drums." Drum-weight savings alone is about 150 lb. per wheel. Then add in composite springs and fiberglass springs, and the weight continues to drop off the trailer, thus boosting payloads. Maintenance issues are a concern. "There is higher maintenance with aluminum, but when you’re getting 25-30% more payload, then it’s worth it. Today’s side panels are easy to replace because they’re bolted in place," observes Pieri. Operator care is needed, especially when it comes time to tamp the load. "The bucket presses down into the trailer, and that bucket can do severe damage to top rails. About 95% of top-rail damage comes from loader error," Pieri states. He adds that tunnels, such as what the City of Oxnard has in its operation, make it possible to move the trailer from wheel stop to wheel start in as short as five minutes. When asked about whether to buy a live floor or a stationary body, Pieri responds, "As most trailers go beyond the 50-mile range, the operation should seriously look at tipper trailers. They’ll gain about a ton and a half per payload. When the landfill is beyond 50 miles, about 70% of your cost is mileage-related, so you need the greatest possible net payload." He also mentions that live-floor trailers are predominant in southern California because many landfills don’t have tippers. "Some landfills close by noon because of permit limitations, and haulers have to select other landfills. If they have a tipper trailer, then they’re limited to which landfill they can use." He adds that moisture loss from the load is not an issue. "If moisture retention was a real issue, you would use a tipper trailer and haul a sealed load." If the transfer facility is able to precompact loads, then rear loading into an even lighter trailer is feasible. "You also can use a 44-foot trailer to achieve a 28-ton payload instead of a 48-foot," Pieri points out. Either way, California operators are careful to abide by the state’s load-limit laws. "Enough violations and you go to jail," he warns. Fortunately, other parts of the country make it possible for higher payloads, thanks to special permits. Haulers in New York City, for example, can scale 105,000 lb., while Michigan haulers can haul over 150,000 lb. "But you have to have the extra axles," says John Skelly, sales manager for Mac Trailer Manufacturing Inc. in Alliance, OH. "In Michigan, it’s not uncommon to see refuse trailers with seven axles, and those can haul over 57 tons of payload." The difference is that a standard tandem axle can haul 22 tons of payload in areas with 80,000-lb. load limits, while a permitted tri-axle in New York can legally haul 30 tons. "Today’s haulers get paid by the ton, not by the mile," Skelly points out. "So the more they can haul, the more they can earn." This is especially critical in cities where so many landfills have closed that the haulers will travel as far as 500 miles each way. For those operators, trailer maintenance needs are critical. "Trailers out of service can cost as much as $1,000 a day. Time is money. So the goal of trailer manufacturers is to keep the structural quality of the trailer strong enough to last longer, to have less maintenance or downtime during its life," Skelly notes. Today, with proper maintenance, 10 years is fairly standard as an expected trailer lifespan. Skelly relates that Mac Trailer’s 6- x 9- x 5/8-in. corrugated top rail and 10-in.-wide uprights with 3.25-in. stiffeners help keep the trailer light but strong in critical areas. "This gives the trailer a very competitive weight, yet it can handle the challenges of loading and unloading under less-than-ideal conditions." The real challenge comes in handling packing abuse. "Haulers get paid by the ton, so they really pack it in. If they’re getting $15 per ton, then packing in an extra three tons adds $45 to the load. Even with just one run a day, six days a week, that difference is over $1,000 a month," Skelly calculates. But he cautions, "Don’t sacrifice strength for tonnage. Also, when looking at a haul, look at the distance and the type of equipment the destination site has for handling trailers, and make sure it can handle your trailer on its dumping system." He also notes that with a live floor, it takes less than 10 minutes to unload a 23- to 25-ton payload. "That’s 120 cubic yards of garbage walking out the back. The tipper trailer costs 20% less and weights 2 tons less and takes less than 90 seconds to unload, but you have to pull on the platform, unhook, untarp, release the back door, take dolly legs down, then put it all back together after the dump. This can easily add 20 minutes per trip to the total operation." So by paying attention to each facet of the operation, especially when it comes to equipment choices, a MRF or transfer station can be assured of a more harmonious and cost-effective operation.
|
|
|
|
