LANDFILL SPACE IS NOT LIMITLESS — even in the wide open West. The 110-acre Salt River Landfill in Scottsdale, Ariz., for example, is “gridlocked” by a canal to the north and a major highway to the south. “Space was an issue with us since day one, and we needed to extend the life of the facility,” says Frank Velazquez, the landfill's fleet and maintenance manager. Consequently, compactors are worth their weight in gold to compress trash and preserve that all-important airspace, Velazquez says. “We've been looking at compactors, methods of compacting and how trash is deposited,” he notes.

Landfill managers say today's compactors are heavier yet more efficient than ever before. Manufacturers also have improved operator comfort and safety, visibility, maintenance and compaction. And technology has advanced, which has led some landfill managers to use global positioning systems (GPS) for precise grade control, reducing soil cover needs, better compaction and preserving remaining capacity.

With operators working in more user-friendly and safe environments, and with better equipment, the biggest challenge has become staying ahead of the trash flow, Velazquez says. “Trash just comes,” he explains, “and you have to be ready for it.” The latest generation of landfill compactors seems up to the task.

Technology's Time

The decade-old Salt River Landfill accepts about 2,200 tons per day (tpd) of primarily municipal waste, which limits the amount of heavy construction debris and large wires that other landfills must contend with. Because remaining space is a concern, packing trash down tight is important, and “[compactor] weight is everything,” Velazquez says.

The facility first used two 826 compactors made by Peoria, Ill.-based Caterpillar. Years ago, Velazquez says, the decision to purchase a new compactor was fairly simple. “Technology wasn't really there, as far as how to evaluate the needs of a compactor, other than it was heavy and you could run over the trash a couple times,” he says.

But because the landfill's policy is to upgrade compactors every three years or 7,000 hours — Velazquez has witnessed two generations of machines and accompanying improvements. Today, Salt River uses two compactors with GPS.

“The GPS system has helped us to understand the best method of compacting and gives us a day-to-day viewing of where we've been and what the compactor is doing in terms of passes over the trash,” Velazquez says. “It's given us an insight into how much better we can be, as opposed to what we have been.”

In October 2001, the Olinda Alpha Landfill in Brea, Calif., began using Caterpillar's Computer-Aided Earthmoving System (CAES) to test grade control. One of three landfills managed under Orange County's Integrated Waste Management District (IWMD), Olinda Alpha is 565 acres and can accept up to 8,000 tpd. The landfill has five pieces of heavy equipment, including two compactors. Operators routinely transfer from one IWMD landfill to another, so being able to hop in a cab, with up-to-date information at their fingertips, is critical.

Information to assess operations is collected from the GPS data, onboard computing and sensing, and computerized information in an office. Once installed on compactors and other heavy machinery, operators can view an in-cab color work plan, which shows real-time information such as how many passes a compactor has made, topographical conditions, and any surface or slope changes that have to be updated.

Using this data, Olinda Alpha Landfill already has improved grade control, reduced the amount of soil needed for daily cover and created a tight, flat trash base, according to Dave Lowry, the landfill's site manager. “Everything that happens, right to the minute, is transferred down to the engineering office and from dozer to dozer and from dozer to packer,” he says. “There are actual read-outs on the screen that will tell them their exact elevation, so you get better compaction, better grading services, and we increase erosion control.”

Interest in GPS for compaction is growing. “I've had visitors here at the site from coast to coast [examining the system],” Lowry says.

Packing Fundamentals

Of course, all the technology in the world won't help if compactors don't stick to the basics. Therefore, Jimmy Rivera, executive director of the Santa Fe Solid Waste Management Agency, which oversees the Caja del Rio Landfill in Santa Fe County, N.M., says he uses three words to choose his compactors: reliability, service and dependability. How quickly a manufacturer responds to service questions is also a deciding factor, he adds.

Caja del Rio opened in 1997 with two relatively small compactors that were adequate for the 300-tpd figures the facility anticipated. Once the landfill was open for business, however, managers realized that the daily waste was closer to 650 to 750 tpd.

With the onslaught of trash, “one of my first goals was to spec and purchase a larger compactor to accommodate the unanticipated volume of waste,” Rivera says. He chose a larger Impact 81K compactor, and is specifying an Advantage 600 compactor, both manufactured by Ottumwa, Iowa-based Al-Jon.

Particularly, Rivera says he paid attention to the wheels and cleats, which he says can make or break an operation. “The wheels and the cleats are specific to the types of soils you're dealing with,” he explains. “In a clay soil, you won't choose wheels with tight teeth. Right now in Santa Fe, it's more of a silty, sandy clay. We want to get that tip of the tooth penetrating as far as into the garbage as we can.” He also looked for wheel-wrap protection to prevent mattresses and diapers from wrapping around the wheel hubs.

Like Caja del Rio, the Orchard Hill Landfill in Watervliet, Mich., is concerned with compaction basics. Construction Supervisor Ralph Balkema says the landfill, which operates Al-Jon compactors, has a goal to get compaction so tight that a tractor-trailer can drive across the trash without building a road.

Service and Support

The real cost of a landfill compactor, Olinda Alpha's Lowry says, is not what a facility pays for the machine, but how much downtime, repairs and upgrades the machine will need before it is put out to pasture. Consequently, product support is essential. “Most of my machines run 10 to 12 hours per day,” Lowry says. “We don't have a huge backup fleet. The old logic was that you had a spare for the spare for the spare, but those days are long gone. You need to have good backup and … product support.”

Serviceability is important at North Carolina's Rockingham County Landfill. The site accepts about 270 tpd and is faced with particularly challenging waste streams — including tobacco dust from local tobacco facilities and lint from textile mills. The facility runs a 3-90 Trashmaster made by CMI Terex, Oklahoma City, daily, and a used and upgraded compactor serves as a backup.

In making compactor purchasing decisions, Donald Hodges, Rockingham's landfill supervisor, recommends examining maintenance. A manufacturer's responsiveness is telling, Rivera says. You want a company that can take the user's ideas and complaints and make changes in ergonomics and automator comfort, he says.

Operator Comfort and Safety

Machines are usually only as good as the humans who drive them. So most compactor manufacturers have made strides to improve the cab experience, such as in steering and air conditioning.

Steve Pendry, landfill superintendent for the High Point Sanitary Landfill in High Point, N.C., says visibility from the cab is important so that “operators are not always looking forward and backward and getting whiplash.”

Salt River's Velazquez adds that controls should be easy to operate. Even shifting the lever to move forward and backward — a compactor's primary movements — should be evaluated to ensure it's not a burden to operators. Joysticks instead of steering wheels allow the operators to have both hands doing light physical motions, he says. With the joysticks specified in his landfill compactors, drivers “don't appear as tired at the end of the day,” Velazquez says.

Other creature comforts can play an important role. For example, Velazquez says drivers want machines with air conditioning but not if vents are poorly located. You don't want “[drivers'] feet [to] be cold but their heads … sweating,” he says. Additionally, some features are region-specific. For example, a cab's larger windows, which may be designed to improve visibility, can create a greenhouse in Arizona's heat, he adds.

Open to Ideas

Although landfill managers generally are pleased with compactor technology, they still like to scrawl suggestions for improvements on paper napkins — as Santa Fe's Rivera has done — and have manufacturers actually consider their ideas for improvement.

Caja del Rio's Rivera, for example, says he hopes future compactors will be more ergonomically sound. Training is always an ongoing need, but Rivera adds that manufacturers already are paying more attention to this. “Before they would sell you a piece of equipment and give you a walk-around and a manual,” Rivera says. “Now they're offering week-long courses on troubleshooting, dos and don'ts.”

At the Glasgow Regional Landfill in Glasgow, Ky., Manager Alvie Morgan would like to see safety feature upgrades. The landfill serves 14 counties in south-central Kentucky and accepts up to 90,000 tons of waste annually. Currently, the landfill packs waste with a Caterpillar compactor, and an older Al-Jon model as a backup. Routinely, waste is thrown up toward the cab, and recently a metal post flew right through the windshield. Thankfully, Morgan says, the specified cabguard protected the operator, but he now suggests all compactors come with standard cab protection.

Salt River Landfill's Velazquez hopes that compactors will one day incorporate more design intelligence, primarily to determine whether a particular pile of trash is light and airy or already heavy and compacted. “The only way you really know is when you're pushing it,” Velazquez says. “If the load's already been compacted, you don't want to break the nucleus of that … whereas other times you have a light load that you are pushing forever.”

No matter the make or model, landfill compacting will always be a weighty issue. Donald Hodges says that his dream machine would be even heavier — “not necessarily bigger,” he adds, “but just heavier.”

Kim A. O'Connell is a contributing editor based in Arlington, Va.