Michael Fickes

SCALES ARE AN UNASSUMING yet necessary part of the waste business. In addition to telling transfer station and landfill operators how much trash is coming and going, they also are boosting operational and administrative productivity across the country.

The city of Scottsdale, Ariz., for example, weighs outgoing waste loads carried by a third-party contractor to track costs at its landfill. In-ground scales at the city's transfer station also help officials to record weights and calculate fees and costs. Located beneath the transfer station loading pit, the scales check trucks' overall weight and distribution of weight across trailer axles.

The city's scales help to promote efficient transfer operations from the moment a load arrives at the facility by ensuring that trailers are full but not overweight, says James Livingston, systems coordinator for Scottsdale's Division of Solid Waste Management. “Our goals are to be accurate, to keep records properly and to operate efficiently,” he says. By evaluating data recorded on inbound scales from Cardinal Scale Manufacturing Co., Webb City, Mo., Livingston says he can monitor the productivity of the city's residential collection drivers.

Did this driver or that driver handle a full day's tonnage during his or her shift? If not, scanning the scale data can help Scottsdale sanitation officials figure out why not, Livingston says.

On Wheel Loaders

Recognizing scales' measurable value, a number of transfer station operators now have begun using the equipment on wheel loader buckets to control the weight of trash loaded onto transfer trailers. For some, wheel loader scales are producing an impressive return on investment.

Office Paper Systems Inc., a Gaithersburg, Md., recycler, operates the Northwest Transfer Station in Baltimore, Md. The company uses this facility to direct more recycling materials to its processing plant. Simultaneously, the company must transfer trash flowing through the transfer station to disposal sites. To speed loading times without under- and over-loading trailers, Operations Manager Mark Minnick recently installed Loadrite scales on wheel loaders.

The wheel loader scale system costs about $8,000 and includes: a computer and display in the cockpit; a trigger mounted on the boom of the wheel loader that tells the system when to weigh the bucket; and a transducer strain gauge that measures pressure within the machine's hydraulic system and converts the reading to weight. Computer controls enable the operator to record the weight in each bucket, add successive bucket weights and clear the memory for the next truck. The system also allows an operator to maintain a weight in the scale system's memory while the loader handles other tasks — such as pushing newly delivered trash up into a pile. When loading begins again, the operator presses a button, and the system continues adding lifted weights.

The goal is to load transfer trailers to capacity quickly — for the sake of productivity — while avoiding overloads that can delay a truck's departure, compromise safety or draw a fine from regulators monitoring truck weights on the highway, Minnick says. The wheel loader scale system is crucial to Northwest's operations because the facility does not have a tri-axle scale. Prior to purchasing the wheel loader scale, Northwest equipment operators loaded trailers by sight and then checked the weights at the facility's scalehouse.

“The trailers would always be too light or too heavy,” Minnick says. “So we would take the trailers back to the dock, dump some trash off or put more on, and reweigh the trailers at the scalehouse. Sometimes we had to [repeat the process] more than once for each trailer. Each trip added 45 minutes to the process and cost a lot of money.”

Now, the wheel loader system enables operators to distribute a load evenly between the front and back of the trailer without overloading axles. And the total amount of trash in the trailer can be accurately measured. “We still have to adjust loads now and then, but that is [because of] the operator's error, not a problem with the scales, which have a low error rate,” Minnick says.

Jason Bazemore, assistant site manager at the Tampa, Fla., Metro Recycling and Transfer Station, a Republic Services Inc. facility, also is singing the praises of wheel loader scales. Metro transfers about 400 tons of construction and demolition refuse and bulk materials every day. The facility installed a Loadrite scale on a wheel loader approximately one year ago to reduce transfer trailer overloads. Now, the facility doesn't know what it would do without the equipment.

“We had a period where the wheel loader with scales was down for transmission repairs, and we had to rent another wheel loader without scales,” Bazemore says. “It was very costly. Every time we loaded a trailer, we had to bring it back [to the facility] and unload some [waste]. The return trips delayed our entire operation.”

Return on Investment

It may not seem costly to reload one transfer trailer or even a couple, but reloading costs add up, operators say. Suppose a transfer station loads 100 trucks per day, 312 days per year, with two wheel loaders. If 20 percent of the trucks are under- or overloaded and require 15 minutes to drive back, reload, reweigh and get on the road, this will cost an operation time and money. Suppose wheel loaders cost $100 per hour to operate, while trucks cost $75 per hour . Although the cost per hour for wheel loaders is higher, the reloading time for the 20 trucks that are not the correct weight could add $375 in operating costs.

A return on investment calculator on Loadrite's Web site illustrates how equipping two wheel loaders with scales can boost the financial performance of a transfer station. According to the calculator, the hypothetical operation could save $148,200 per year on loader and truck operations. The savings, which come from getting the trailers loaded properly the first time, would pay for two wheel loader scale systems in less than a month, the company indicates. Savings for the other 11 months would go to a waste operation's bottom line.

Assisting Networks

Obviously, all transfer stations want to load trailers productively, but large networks of transfer stations are finding that scale technology also can help to measure and manage the productivity of an entire waste department's administrative systems.

The New York City Department of Sanitation (DSNY), for example, recently struck a deal to include customized point-of-sale software for driver-assisted scale data management systems at its transfer stations. Under the contract, PC Scale, Oxford, Pa., will provide DSNY with software and peripheral devices such as scale house terminals, radio frequency identification (RFID) units and proximity readers for city transfer stations.

According to Steve Stam, director of information technologies (IT) for DSNY, the scale contract has three objectives. First, the system must funnel accurate and appropriate data from city transfer stations to DSNY's central IT systems.

As simple as that sounds on the surface, it is a complex task, he says. Today, third-party vendors using many different technologies manage most of the Big Apple's transfer stations. In most cases, these operators transfer refuse from city trucks and from trucks operated by other vendors. “We wanted the new system to enable our vendors to continue with their processes, whatever they are,” he says. “At the same time, we wanted our data to flow from the transfer stations into our systems in an appropriate way.”

The second objective of the deal was for the new system to be flexible enough to handle new transfer stations that the city might build in the future.

Finally, the new system would have to provide opportunities to improve productivity in the future. For example, if the city decides to automate the process by which drivers enter in data at the scalehouse, the system must work with driver-assisted terminals, Stam says.

In short, DSNY specified a system flexible enough on the front-end to be modified as needed and flexible enough on the data output side to accommodate DSNY's large IT processing needs. “After the weights are recorded, our 59 sanitation districts go through a process we call ‘claiming the load,’” Stam says. “When the data arrives here, we have to confirm that what the data says happened really did happen. This is a complex process, and the data coming from the scales at the transfer stations is just part of a much larger process that correlates many different pieces of data.”

In the past, when a truck delivered a load to a transfer station, DSNY created a record that included the truck's identification number. When that truck returned to its home base, the driver delivered a log to his or her supervisor who keyed in the truck's transfer station stops, as well as the rest of the truck's activities for the day.

If the transfer station attendant entered the wrong truck identification number, that truck's load was lost, and someone had to spend administrative time finding it. On the other hand, an RFID system at the transfer station will always identify the truck properly. If the software logging the transaction can send that data to DSNY's IT department, it will assure an efficient correlation with data coming in from each of the sanitation districts.

“The weakness in these systems always comes down to communications,” Stam says. “That's where the disruptions occur. To be efficient, the two pieces of data always have to match.”

If the data entries don't match, someone has to spend time finding out why. If the reason is nothing more than a data entry error, DSNY has wasted its time. And if scale systems can eliminate time previously spent running down mismatches, that has real productivity implications, he says.

Michael Fickes is Waste Age's business editor.