To Anthony Roman, Orlando, FL–based district manager for Waste Management Inc.’s north Florida transfer stations, what some might consider little things make all the difference in improving the efficiency of truck loadout. Dissatisfied with how short transfer trailers were of their legal weight limits at one of two transfer stations in Okaloosa County, he had onboard scales installed on the front-end loader in late 2010 and has doubled loading efficiency.
It’s one example of how MSW managers are using weighing and ticketing systems to improve efficiency at transfer stations. These improvements are crucial for many companies because, with land becoming scarce due to zoning and environmental restrictions, these facilities are increasingly distanced from developed areas. The cost of hauling to landfills is becoming increasingly fixed, so many firms are looking more closely at transfer stations themselves for ways to cut costs.
Roman, who manages nine transfer stations from Sarasota on the southwestern coast to Fort Walton Beach on the western panhandle, reports that the Okaloosa County facility takes in 600–900 tons a day during the summer peak season. In addition to commercial loads, residents drop off their own refuse. He saw that operations overseen by a subcontractor with a soon-to-expire contract could be more productive.
“The other transportation company was operating the tipping floor, and they didn’t have a scale on their loader,” says Roman. “I saw them make a minimum of two trips to the scale to get the weight right—the owner of the company didn’t want a tractor-trailer to go out with [a net weight of] less than 23.5 tons, and Waste Management won’t allow a trailer to go out over 80,000 pounds on any roads—they will not get a ticket.”
When Waste Management took over day-to-day tipping-floor operations, it purchased a new Volvo L150F front-end loader. Volvo alerted him to the existence of a Loadrite L-2180 onboard scale system. The system includes friction and ambient compensation technology (FACT) software for calculating accurate weights, multiple-point weighing at several points throughout the lift cycle, storage of calibrations for up to five different attachments, daily total weight tracking for up to 100 material types, and tracking of loads by customer. A key feature of the system that attracted Roman was an “active tip-off function,” which allows the operator to adjust the last bucket to pinpoint the target load weight.
“That caught my attention,” Roman says. “Let’s say you have two tons left to load and you pick up 2.5 tons. In the past, you had to tip off, bring the bucket back, lower it down and raise it up again. If you didn’t take off that half a ton, you would have to repeat that whole process, whereas with this system, you press the tipoff button and it tells you to wait while it reads as it does calculations, and it tells you how much to tip off. As you tip your bucket, garbage is dumping until you get that half-ton you need. It’ll do its calculations, and 99% of the time half a ton is exactly what you’ve got when you’re done.”
“I requested that Volvo have the L-2180 installed on the machine with a printer because my ultimate goal was to allow better flow without our transport trucks getting up on a scale,” adds Roman. “And my boss had asked me to minimize traffic because it was affecting the drivers’ productivity. I only have one scale at the facility and the more trucks we can eliminate from going across the scale, the better the traffic flow is in and out.”
Roman notes that the user can either “load up” to a target weight or “load down” to zero. Additionally, ticket printing offers options. The system can be set up to print gross, tare, and net weight (short version), or it can print a list of individual lift weights (long version). He says that the operation prints out the short version. The ticket puts drivers in compliance with DOT regulations, although the onboard system cannot be state-certified, according to Roman. Still, the L-2180 is calibrated against the state-certified outbound scale, he adds. The calibration confirms that the onboard system consistently provides weighing accuracy to within 1%.
Because the system is new, Roman has not been able to quantify how much money it is saving his division; but time is money, he acknowledges. “As far as time, the other company used to take approximately 35 minutes to 45 minutes to load one truck. We do it in about 17 minutes.”
Weighing the Yard Trailers
In Troy, OH, the Miami County Solid Waste District is also an advocate of onboard scales—but management there focuses on yard trailers at its transfer operation.
Commercial haulers and residential customers back into a 160-by-180-foot transfer station and dump their loads onto the tipping floor. The county does some segregating of material (e.g., metals and cardboard), baling up the cardboard. A Caterpillar 938 front-end loader equipped with a customized bucket is used to load the yard trailers and compact the loads. Then, a Caterpillar 318 excavator equipped with a rotating grapple provides additional compaction until most trailers are loaded to a 26-ton net weight. According to Scott Pence, solid waste division manager, the facility has reduced its trailer loads by five since 2005 through the use of this equipment.
A previously used county transfer station was built out of an incinerator, and an overhead gantry crane was used to load trailers. The current facility was constructed in 1998. Miami County entered into a joint agreement with neighboring Montgomery County to combine waste-streams and solicit more competitive bids for hauling the loaded trailers to a landfill in Brown County. “This top-loading operation is a lot more efficient,” says Pence. “We’re able to load a trailer in about 10 minutes. We’re actually waiting for waste to come in here; as soon as it gets dumped on the tipping floor, it gets loaded out right away.”
Miami County’s 48-foot Titan trailers are a key component in its “drop-and-hook” transfer operation. Before acquiring the Air-Weigh scales in 2010, operational efficiency was less than ideal, Pence says. “[Weighing the trailers] was pretty much a guessing game,” he says. Debris getting onto outbound scales was a problem and, in the winter, trailers dripped a lot of water onto the scales, which caused problems with their operation.
The onboard electronic scales measure and display refuse vehicle weights, including drive axle weight, steer axle weight, gross vehicle weight, and net payload on an in-dash LCD display inside the yard tractor cabs. Compatible with either air-ride or mechanical suspensions, they utilize deflection sensor technology, which allows the accurate weight measurement on steer and drive axles with mechanical suspensions. The system is equipped with alarm outputs, although Pence reports that the operation does not use the alarms. Rather, yard tractor-trailer drivers let the loader operators know when the trailers meet specified weight by viewing the display.
Pence says that the onboard scales allow the facility to load most tractor-trailers to essentially their maximum legal weight—usually to within 300–400 pounds. “We take pride in being as efficient as we can be,” he says. “We have a skeleton crew: I have a loader operator, one truck driver, and we have another employee who floats back and forth who primarily operates the excavator. We’re trying to be as efficient as we can today because cutting your costs is very important. We’re going to the landfill about 220 miles one-way, so we have to maximize our loads to eliminate as many as possible. With the onboard scale system plus the way we compact our loads, we’re getting 26-ton loads. That’s pretty good with the way we run this top-loading operation. It’s definitely a time saver; the biggest thing I appreciate is taking the guesswork out. You’re able to see what you’ve actually got on the trailers.”
Maximizing net weight in a trailer improves job satisfaction among transfer trailer drivers, according to Pence. “One thing that’s made our drivers very happy is that they get paid per ton,” he says. “Putting these scales on keeps the transfer operation very happy, too—they’re going out with their maximum payloads. Today, with the way fuel prices are, any way you can cut is a benefit. This has helped out tremendously in terms of maximizing loads coming out of here.”
Optimizing Efficiency With Onboard Scales
Onboard scales can serve as a key component in the MSW manager’s cost-cutting strategy at transfer stations, according to Vulcan On-Board Scales. The most easily measured benefits, according to Vulcan, are optimizing the payload weight at the time of loading and prevention of overweight fines. Onboard scales can also reduce the time required to readjust the load weight.
The company points out that, due to the construction of more transfer stations and greater distances to travel to landfills, transfer station operators are under increasing pressure to reduce transportation costs by maximizing the weight of each payload without overloading the vehicle. Also, Vulcan notes, transfer station operators are getting increasingly concerned about shielding themselves from potential liability that would result from an overweight vehicle’s involvement in an accident.
Transfer station operators have certified in-ground scales onsite but face barriers to locating them in the loading area, Vulcan points out. Maintenance of these scales can be difficult and expensive due to the abuse they take and weather. Additionally, every transfer vehicle must line up to be weighed at the certified scale after loading and, typically, underweight vehicles are waved on unless they are grossly underweight. Overweight vehicles typically are sent back to offload; the temptation does exist for management to send slightly overloaded vehicles out anyway. According to Vulcan, studies show that transfer vehicles determined to be overloaded are subsequently underloaded by 20% to 25% on average.
Vulcan summarizes the key benefits of onboard scales. They allow MSW managers to get transfer vehicles loaded to the maximum legal gross, net payload and axle weights onsite quickly, without drivers having to wait in line or drive to the nearest platform scale, which might be located a great distance away. Onboard scales also eliminate the need for drivers to have to readjust their loads and return to the loading area and wait in line again. Running trucks overweight is increasingly expensive; keeping transfer vehicles loaded at the legal weight eliminates liability exposure that would result from increased braking distance. Hauling loads that the vehicle was designed to carry reduces the maintenance costs of brakes, tires and suspensions, and frames and bodies also last substantially longer. Lighter vehicles have a more constant braking distance, and tracking around corners is more predictable. Many mills and distribution centers prohibit the unloading of overweight vehicles solely to reduce their liability exposure.
Although many variables are involved, Talbot incorporates several costs into an analysis, including underloading, overweight fines, fees for weighing at certified scales, downtime involved in weighing and load readjustment, and contends that onboard scales can pay for themselves in four to six months.
Jack Ewing, sales manager for the SI Onboard brand of Vishay Precision Group, adds that interest is growing in onboard weighing for trucks equipped with air suspensions used in rolloff and packer systems. Ewing points out that, besides reducing liability, onboard scales can make it easier for MSW managers to reduce maintenance resulting from overloaded refuse trucks and increase the trucks’ longevity.
The SI Onboard Airscale system provides gross or net vehicle weight on any truck with an air suspension by monitoring air pressure from a truck’s air suspension and converting it to a weight reading. Axle group weights are provided, as well as gross and net weights. Rear-axle-group-only and front-axle-group-only systems are available. The system reportedly is accurate to within 2% and includes a printer, relay board, and handheld remote.
The system consists of air-pressure transducers, junction boxes, a meter, cabling, and mounting hardware for air-pressure sensors. The air sensors connect to an SI Onboard factory-sealed junction box and the signal cable connects the junction box to the in-cab indicator. The air sensors and junction boxes are sealed for protection in harsh environments.
SI Onboard also has Trojan transducer systems that provide group axle weights and total gross vehicle weight for straight trucks. The system also is said to be accurate to 2%. By design, the system does not require the disassembly of the vehicle chassis, suspension, or truck body. It typically consists of one Trojan transducer on the front axle and one or two Trojan transducers on the rear suspension or differential. Installation involves placing small Trojan mounting blocks to each Trojan transducer’s attaching location and the bolting the transducer to the mounting blocks.
Cabling is then run from the Trojan transducers to a transmitter and then to the meter in the cab of the truck. SI Onboard says that Trojan transducer systems are environmentally protected precision strain-gauge instruments designed for external mounting to vehicle suspension members and differentials.
In-Ground Scale Protection
It’s not as though manufacturers of in-ground scales have not taken notice of the aggressive environment in which these units operate. Cardinal Scale’s Guardian Hydraulic Scales are designed to address problems due to lightning that can cause electrical surges, moisture, and other deleterious elements.
These problems can cause unstable weight readings and damage to junction boxes and load cells. In low-lying areas, water can often flood and submerge a scale, which allows water to seep into cables, boxes, and the load cells. The result of this damage, Cardinal points out, is the cost to repair, which does not even include scale downtime.
Cardinal notes that the threats posed by these elements have spawned an industry in itself: the development of devices designed to provide added protection for scales. Rather than utilizing electronic components or junction boxes underneath the scale deck, the Guardian is equipped with copper or stainless-steel lines filled with special hydraulic fluid. These lines are connected to a “Totalizer” via high-pressure rubber hoses that completely isolate the scale from the scale’s weight indicator. The Totalizer encloses the Cardinal PTG pressure transducers, which are fluidly coupled to SST hydraulic load cells to convert the pressure signal into an electrical signal for digital weight readouts.
These scales use software that is used to track waste, vehicles, customers, and other items and suits truck-, railcar-, and ship-loading transfer operations.
Ticketing and Accounting
The Montgomery Regional Solid Waste Authority in Christiansburg, VA, has found that information technology is the means by which ticketing and accounting can be automated. For the past several years, the authority has utilized Carolina Software’s WasteWorks system, which reads a vehicle’s weight automatically from a scale, then computes the charge by ton, cubic yard or quantity, and prints a ticket for cash or charge account transactions. The system error-checks as data is entered to ensure accuracy. The software computes pricing, including special contracts and discounts as well as special taxes.
In addition to generating a refuse ticket, the program includes customer billing and financial reporting in the base product, so it is not necessary for an operation like the authority to purchase and learn additional accounting software. The program also includes several standardized management reports and also allows the user to create customized reports.
The authority’s two-bay transfer station takes in 70,000–95,000 tons of refuse per year from Christiansburg, Blacksburg, Montgomery County, and Virginia Tech University. Alan Cummins, the authority’s executive director, was hired about five years ago after having served as solid waste director for the city of Sheridan, WY, which had switched from a different ticketing and billing system to WasteWorks. Having some familiarity with the program, Cummins says he is glad that evaluating a new program was not necessary.
A major advantage of the program is the ability to bill customers according to the various material types brought into the transfer station, according to Cummins. The authority charges different fees for various types of refuse, such as MSW, wood debris, brush, or white goods. The same holds true at the material recovery facility, where refuse such as commingled containers without glass and commingled containers with glass carry different fees. “Right now, with the commodity prices so good, we’re not charging for anything, but in the past we’ve had a fee for mixed paper and a different fee for source-separated material like a slug of cardboard or newspaper,” says Cummins. “Just being able to put in a variety of material types and a variety of prices helps us very much.”
Commercial vehicles that cross the inbound scale are assigned a charge account. Codes or license plate numbers are entered for cash customers. “You weigh them and then you put in the material type, and it automatically gives you weight,” Cummins explains. “Then, they go when they unload their waste, they come back and pull that ticket. It automatically tells them the weight that was disposed and the price and that is then put into the system.” The operation can have a customer segregate scrap metal—which is disposed of for free—from a load and then have the customer go over the inbound scale again. With the coding system, the scrap metal weight is deducted from the ticket, but no charge is assessed. Or, coding can account for cardboard, for which a fee is assessed, once it is segregated from a load and the driver receives a ticket with the itemized weight and price for cardboard.
“At the end of day, we have it set up within our computer network to automatically download all of the data from our scale house into our network,” Cummins continues. “If you have a user number you can get into the WasteWorks program and see how much of a specific material type came in the previous day, the previous two days, or the previous month. You can break it down into material type and days. It’s just incredible the amount of data that you can pull up if you just want how much solid waste for a specific amount of time. If you need numbers, you can get them.”
The program’s reporting capabilities can be a boon to customer service “just for information that you need on the dime,” he says. “If you have a specific hauler and you’re wondering how its tonnage was one month compared to another, you can actually put in a code for how much of a material type it brought in for specific time period.”
Reports can also help in forecasting, Cummins adds. He can determine how much tonnage and revenue came from different types of refuse, such as sludge, MSW, or wood debris. He can also produce a recycling report showing what commodities such as cardboard or office paper account for.
Some reports are financially oriented, he adds. The authority can determine which accounts are 30 days or 60 days past due, for example, triggering a letter. Monthly billing gets completed very quickly, he adds. “I keep fiscal year data, and I’m able to keep calendar-year totals and fiscal-year totals,” says Cummins. “We use them for our budgeting just for forecasting material trends. We’re looking at short-term trends and long-term trends, and it really does help you with your budgeting every year.”