Chad Phares and Lane Blount
The landfill is North America’s most common solution for handling the continuous and never ending flow of waste produced by our society. North America’s largest living organisms are the “faces” of the landfills. Landfills live 24 hours per day, nonstop, tirelessly with no regard for weather, holidays or vacations. Trucks back up, unload their waste, drive away and repeat the process multiple times per day. Waste flow comes in from everywhere, day in and day out. Its last destination is to become part of the living landfill.
Managing waste flow is one of the most challenging jobs in North America. Landfill Managers have been given the job to minimize the impact of this waste flow on the available space in the landfills. Their goal is to compact as much material in the smallest amount of the limited air space available resulting in maximum compaction. Landfill operations typically require a landfill compactor to achieve the maximum compaction. There are only a few manufacturers in the world of landfill compactors. Each manufacturer claims they offer the market features that contribute to achieving the maximum compaction. These monster machines weigh between 25 and 60 tons, move at speeds up to 7 MPH and run 24 hours per day. It’s common for landfill compactors to operate more than 2,000 hours each year. What features to choose as well as the size of machine required in a landfill is usually based on the volume of waste accepted at the landfill each day. Choosing the right landfill compactor can be difficult, but can result in millions of dollars favorably hitting the bottom line. How does a Landfill Manager make the right choice?
#1: Wheel or Drum Design
Wheel and drum design are essential in choosing the right landfill compactor. It is commonly accepted that the correct optimized combination of the crushing teeth on the landfill compactor and the ground pressure will result in the highest compaction rates. The designs available in the market today are: 1) standard four wheel oscillating 2) triangular four-wheel pattern and 3) full-width twin drum design.
The more crushing teeth engaging the surface per wheel/drum rotation, the higher compaction levels can be achieved. The number of crushing teeth per machine range from 80 to 220 depending on the weight classification of the landfill compactor. Once the decision is made regarding the weight class required for the landfill, choose a machine with the highest number of crushing teeth.
The second aspect of the importance of the wheel/drum design is the area coverage per pass. The size classification of the machine determines the area coverage to some extent, but the design differences between the three listed above make the most difference. The TRC full-width twin drum design covers more than 30 percent more area than the standard four-wheel design, and compacts the area twice as fast as the triangular four wheel pattern design.
#2: Frame Design
Another feature to consider when choosing a landfill compactor is an oscillating frame design or a rigid frame design. Oscillation in the frame allows one wheel to drop into voids or ride on high points while distributing a maximum of 25 percent of the machines weight to each wheel. A rigid frame design does not drop into voids, but spreads level layers of waste resulting in a smoother, densely compacted area. The TRC full-width drum design rigid frames ride on high points while distributing a minimum of 50 percent of the machines weight on the mound of waste; the triangular four-wheel pattern design rigid frames distributing a maximum of 33 percent of the machines weight on the same mound of waste.
#3: Ground Clearance
Ground clearance is important in a landfill for a couple of reasons. Low ground clearance is a detriment to a landfill is because it will cause the machine to dig out previously compacted waste and waste will work its way into the belly pans of the machine creating fire hazards and power train stoppages due to debris interruption. The landfill compactors available in the market today offer ground clearances between 19 and 35 inches.
#4: Drive Systems
Two options of power train drive systems are offered in the market today. One option is the “Power Shift Transmission” system. This system uses a power shift transmission, torque converters, transfer gearboxes, drive shafts and universal joints, differentials, disc brakes, clutch pedal and clutch, and brake pedal and controllers. The second option is the “Hydrostatic System”. This system eliminates all the above components in the “Power Shift Transmission” system and replaces them with pumps, final drives, final motors and more simplistic operational control systems. The hydrostatic system is designed for the quick change of directions required in a landfill operation and requires less preventative maintenance and cost less to repair or replace.
#5: Wheel Cleaning
Scraper bar systems offered on each machine keep the wheels clean during compaction. The effectiveness of a landfill compactor is greatly reduced if the waste builds up on the wheel or drum as it causes the effectiveness of the crushing teeth to be diminished. Having a scraper bar system that will eliminate the waste build-up is essential in being able to reach the highest compaction rates. All manufacturers of the four wheel designed compactors offer scraper bar attachments to clean their wheels. The problem with this design is after a period of time the attachments usually break eliminating the ability to keep the wheels free from waste build-up. Some manufacturers market a “self-cleaning” cleat design, but their ability to consistently and in all types of waste keep the wheels clean has not been sufficiently proven.
#6: Operator’s Compartment
Key features of an operator’s compartment or cabin not only include the sound levels and ergonomics of the inside of the cab, but the structural design and location of the cabin on the landfill compactor. Most manufacturers offer similar ergonomic features inside the cab including adjustable seats, head rest, heated seats, radios, CD players, heat and A/C, joystick control and others.
Features that make the most impact of achieving the highest compaction are the comfort of the driver and the visibility of the waste being compacted. Most manufacturers’ landfill compactor designs locate the cabin on the rear frame of the machine. This location is closer to the engine compartment; therefore, causing a higher dB (A) noise level. The rear cabin location also creates vision impairment for the operator to see the full blade at all times, as well as, the some of the waste being driven over.
#7: Machine Intelligence
Finally, an important feature to consider is the technology offered with the machine. There are many types of technology offered in the market but, for Landfill Managers, the simple question is “what technology will put more favorable dollars to the bottom line?” The answer may not always be easy, but it should point to any technology that provides for higher compaction and lower operating costs. Each landfill compactor manufacturer offers technology they claim can achieve those goals.
The Landfill Manager’s choice can become easier when they follow these seven essential features in order to choose the best landfill compactor. Landfill Managers will be tasked with other duties as new solutions and methods to handle our never-ending waste flow are developed. Making the correct choice will enable them become more successful.
Chad Phares is Vice President of Humdinger Equipment, Ltd. (Lubbock, TX). He can be reached at (806) 771-9944 or e-mail [email protected].
Lane Blount is Regional Sales Manager for Tana North America, Ltd. and is based out of Cleveland, TX. He can reached at (832) 594-2818 or e-mail [email protected].