Landfill compactors maximize density using a combination of weight and physical manipulation to crush down trash into the thinnest possible layer. The goal is to break down the number of air voids in the waste to conserve valuable airspace.
Keeping this in mind, manufacturers recently have been designing heavier machines that exert more force at the wheels. Older compactors typically weighed between 40,000 pounds and 60,000 pounds. But today's equipment weighs approximately 80,000 pounds, with vendors offering compactors weighing up to 120,000 pounds.
However, “weight [of the compactor] is not the final answer,” says Mickey Cereoli, national sales support manager, landfill and stabilization equipment for Compaction America Inc., Kewanee, Ill., manufacturer of Bomag landfill compactors. “The difference is the tool that interfaces the weight to the work. If we can make the material more compactible by breaking it down, you get better compaction.”
Sometimes, a smaller machine may be more effective and may be better use of capital, depending on the operating characteristics of the landfill, Cereoli adds. “Some people choose to have two lesser-sized machines. This may double the cost of operators, but if one machine goes down, there's a backup.”
How Well is it Working?
When discussing equipment, efficiency often is described as the maximum density that the compactor can achieve, with some landfill operators claiming they can compact down to 2,000 pounds per cubic yard. However, actually determining how well a compactor is working can be difficult. Density is contingent on the waste type, composition and moisture content, as well as on the landfill's operating standards.
Consequently, manufacturers continue to study how to achieve the best compaction through a variety of techniques, including best management practices at the landfill face. Peoria, Ill.-based Caterpillar Inc., for instance, uses a Waste Fleet Analysis program that allows the customer to input various characteristics about the incoming waste stream and determine what the best compactor and the most effective waste management practices are to achieve higher landfill compaction rates.
Generally, the larger the lift of loose trash, the less likely waste will be compacted through the bottom layer, says Robert Puhalovich, marketing manager for Caterpillar's corporate waste products group.
There also are a host of other options to consider when purchasing a compactor. For instance, several manufacturers recently have enhanced their cabs to improve ergonomics and operating controls. Additionally, today's compactors come with user-friendly seats, quality sound systems, cup holders and storage compartments, to name a few features. Because even with the most state-of-the art machine, a landfill compactor won't work if the driver is not safe and comfortable.
Recognizing these goals, here's what a few businesses considered when purchasing their compactors.
Cumberland County N.J.
For daily operations, the New Jersey Cumberland County Improvement Authority uses two Caterpillar 826G compactors with Caron, Modesto, Calif., traction and compaction teeth, which come with a three-year replacement program.
The authority handles approximately 900 to 950 tons of trash per day, serving 14 municipalities in the county. Additionally, the authority receives waste from anywhere in New Jersey, as well as from other states.
With this constant flow of trash, the authority decided reliable equipment was a priority. Consequently, when it purchased its compactors using the state-mandated competitive bid process, the authority specified a preventive maintenance program and a three-year replacement program.
The vendor is required to respond within 72 hours to fix a problem, says Robert Pollock, the authority's facility manager. “If that machine is going to be down for more than 72 hours, the vendor has to provide us with another piece of the same equipment.”
Additionally, “[the manufacturers] come in on a scheduled maintenance program, and even perform lab tests on the oils to see if there are any problems,” says Ben Germanio, chief engineer.
As a result, “we get very good value on trade-ins because the machine has low hours, and preventive maintenance is kept up on it,” Germanio, adds. “If we keep them under 5,000 hours, we can get the best performance and a better value.”
Waste Management Inc. Reno, Nev.
Dealer support also is important to Waste Management's landfill in Reno, Nev., which handles an average of 4,700 tons per day, with a peak load of 7,000 tons per day. According to Dennis Freeman, operations manager, a few thousand tons of that waste stream comes from interstate waste. To move this volume, the company uses a combination of Caterpillar bulldozers and compactors, including five D-9 series dozers, and three 836s, one 826 and one 816 compactors.
Because of the landfill's remote Nevada location, “dealer strength is very important to us,” Freeman says. If a machine breaks down and a manufacturer can't help us, that hurts efficiency, he says.
Machine reliability also is important, Freeman adds. “In the old days, compactors broke down a lot,” he recalls. “But the technology keeps evolving and [compactors] finally are catching up to the rest of [landfill] equipment.”
Equipment buyers also can ensure reliability by spec'ing the right features. For instance, to prevent wheel slippage, the Waste Management used to spec a double-locking rear end, Freeman says.
“But the [double-locking rear end] just wore itself out, so we took the rear end out,” he says. “The newer models have one locking rear end, and we don't have a spinning problem.”
Boone County, Iowa
Iowa's Boone County landfill, which handles between 40,000 to 50,000 tons of refuse per year, matches equipment to the nuances in the field. For instance, the county uses a Bomag 671 compactor and a backup bulldozer because it “likes the wheel design for compaction and the self-cleaning feature of the wheels,” according to Scott Smith, landfill administrator. “We almost never get any wires wrapped [around the wheels]. We also like the hydrostatic design because we rarely lose traction vs. gear-driven machines that we've had problems with in the past,” he says.
A hydrostatic drive system uses an individual hydraulic pump to control each wheel through a hydraulic motor. Each wheel operates independently from the other three.
However, “don't get tied to any one brand because you may be selling yourself short,” Smith cautions. “There may be something new on the market that you're not aware of that would do a better job.”
To ensure that the county is buying the best piece of equipment, Smith and his staff continually investigate all machine offerings and don't buy “off-the-rack.”
“When we bought [the compactor] two years ago, we looked at others to make sure that we were still getting the machine that best met our needs,” Smith says. That's one of the reasons the county opted for the hydraulic controls.
“I know the operators enjoy the improvements — for example, you can turn [the compactor] with a steering wheel or with a hydraulic joystick, so the fatigue factor is much less,” he says.
If equipment is spec'd and operating correctly, it should make the landfill operator's job easier. “If you operate your landfill correctly, you're not going to be climbing up cliffs,” Waste Management's Freeman says. “The tighter the garbage, the less dirt you are using. Airspace is a precious commodity.”
Contributing Editor Lynn Merill is the director of public services for the city of San Bernardino, Calif.