The Workhorses of Waste

Oct. 1, 2009

It’s been said that the cowboys working the range would pamper their mustangs and often neglect their own comfort for the sake of their workhorses. They made sure that the horses got clean water while the cowboys drank brackish water. The horses were given sweet grass to eat while their riders made do with a cold plate of beans. The cowpokes sacrificed their own well being for the sake of their mounts. And they did so with good reason: Their livelihoods (even their lives) depended on the care of their horses.

The waste industry has its own workhorses, the waste collection vehicles, and they come in various “breeds.” Like the cowboys of old, their riders perform a physically demanding, gritty, unappreciated but absolutely necessary job. Hollywood portrayals notwithstanding, cowboys back in the day were not glamorous; they were workingmen like everyone else. Being a cowboy was a tough way to make a living, something modern waste collectors can appreciate. And like the cowboys of the past, today’s waste collectors need the appropriate mounts with the right capabilities in order to do their jobs.

Basic Types of Vehicles
There are three basics types of waste collection vehicles and three specialized types. Each services a different kind of customer: industrial, residential, recycling, or specialized. The three basic types are classified by the location and manner of their loading operation and include front loaders, rear loaders, and side loaders. The two specialized collection vehicles collect either with a vacuum attachment or with a grappler arm. The third specialized type is classified according to the overall function of recycling.

Managing municipal solid waste is more than landfilling: publicity, education, engineering, long-term planning, and landfill gas waste-to-energy are specialties needed in today’s complex environment. We’ve created a handy infographic featuring 6 tips to improve landfill management and achieve excellence in operations.  6 Tips for Excellence in Landfill Operations. Download it now!

Front loaders (not to be confused with front-end loaders used for earthmoving and stockpile material management) are used to collect waste from dumpsters that collect and temporarily store debris that is typically generated by businesses, retail operations, restaurants, and industry. These trucks combine a forklift with a waste hopper for containment during transport. As the truck approaches a dumpster, it inserts its fork lift arms into metal loops designed for the purpose and located on either side of the dumpster box. Once secured, the forklift arms lift the box up and over the truck cab, turning it upside down as it goes. The top of the dumpster will fall open and allow its contents to spill into the hopper below. Once emptied, the forklift arms return the now empty dumpster back to its position on the ground. Inside the hopper, the waste is compacted by a “packer blade” that pushes the waste back to the rear of the hopper. This increases its density and opens up more free space for the next load. Trucks that are equipped with “pack and go” hydraulics, have superior operational efficiency since the truck can be compacting waste as it moves to its next pickup, removing delays as the truck would wait motionless until the compaction process was completed.

Rear loaders typically accept residential waste from individual trash cans that are emptied manually into the rear of the truck. These trucks are usually serviced by a small crew consisting of the driver and two or more loaders. They are designed to take and compact smaller individual loads of waste, compared with the large bulk loads handled by the front loaders. Partially automated loading systems are available in addition to manual loading. Waste containers larger than the typical waste cans (often referred to as toters) can be lifted and dumped by an auxiliary loading mechanism. Sometimes this loading mechanism consists of a special grove slot in the truck that is sized to receive a standardized waste container. A chain that tightens and wraps itself around the waste container can then lift and tilt it to empty the contents into the back of the truck. No matter how the waste is loaded, it gets compacted within the truck. This is done by means of a hydraulically powered sweep-and-slide blade that shifts out and down to position itself for compaction and then sweeps the waste forward to the front of the tuck. This action effectively compacts the loaded waste and frees up space in the back end for additional loading.

Managing municipal solid waste is more than landfilling: publicity, education, engineering, long-term planning, and landfill gas waste-to-energy are specialties needed in today’s complex environment. We’ve created a handy infographic featuring 6 tips to improve landfill management and achieve excellence in operations. 6 Tips for Excellence in Landfill Operations. Download it now!  

Automated side loaders are collection trucks that pick up intermediate-size mobile garbage bins. Some models have mechanical arms that can reach out 9 feet from the side of the truck to grab adjacent bins. The arm is operated from within the cab by a joystick and is articulated so that it can be operated around obstacles. This allows the entire waste collection effort to be performed by a single worker instead of the typical driver and one to two loaders required by less-advanced collection vehicles.

Recycling trucksare a kind of specialized vehicle used by standard hauling routes. They are designed to manage source-separated waste, collecting and hauling it to a local multistream (“clean”) materials recovery facility (MRF). However, since most waste collection operations nowadays also include a pickup of source-separated recyclable materials, recycling trucks have become an integral part of the standard waste collection vehicle fleet. No compaction is typically performed in these trucks either, but they do come with multiple (usually four) containers, each of which holds a different kind of source-separated waste.

Pneumatic collection trucks are specialized vehicles equipped with flexible pneumatic tubes controlled and positioned by attached cranes or booms. The engines of these trucks can be used to generate a suction force that applies negative pressure to the mouth of the tube. The tube is positioned over an opening (typically a hole to an underground storage unit) and proceeds to suck up the waste into the holding tank on the back of the truck. The tube’s flexibility allows for effective operation even around nearby obstacles.

Grapple trucks are another type of specialized waste collector used primarily in large-scale industrial and recycling activities. These trucks come equipped with a hydraulically operated boom serviced by a clamshell bucket or an orange-peel grapple. The boom reaches out to an adjacent pile of debris or large and heavy waste items and grabs them with the grappling attachment. The oversized waste is then deposited into a dump container on the back of the truck for hauling offsite. Given the size, weight, and irregularity of the waste handled by grapple trucks, they do not typically compact their waste loads during transit.

Operational Characteristics
Standard waste collection vehicles perform two functions: They haul waste to the final disposal site, and they compact each load of waste to increase its density and reduce overall hauling costs. The municipal solid waste deposited at a landfill has a density of 550 to over 650 pounds per cubic yard (approximately 20 to 25 pounds per cubic foot). This is the result of compaction within the truck during collection operations as the truck’s hydraulic blades compress waste that has a typical density of 10 to 15 pounds per cubic foot at the curbside. The in-vehicle compaction effort should approximately double the density and half the volume of the collected waste. However, these values are rough averages only and can vary considerably given the irregular and heterogeneous nature of municipal solid waste.

Holding capacity varies according to make and type of truck. Effective capacity may be reduced by the use of multiple storage hoppers (as in recycling trucks) or due to the nature of the collection apparatus (as with the pneumatic hose) or the physical characteristics of the waste itself (such as large sized, uncompactable debris managed by grapple trucks). Front-end loaders tend to be larger, with body storage capacities of 30 cubic yards to 40 cubic yards. Rear-end loader capacities range from 11 cubic yards to 31 cubic yards, with 25 cubic yards being typical. Side-loader capacities are somewhat smaller still, from 6 cubic yards to 28 cubic yards.

The operational lifetime of a waste collection vehicle is not that much different than for any other similar truck chassis or vehicle performing similar functions (such as dump trucks). The key to prolonging the life of a waste collection vehicle is to perform regular maintenance and repairs as needed. Like similar trucks in a rough-use environment, special care has to be made to the drive trains in general and the transmissions in particular. Aside from the accumulated effects of constant stopping and starting along the collection route, the only real difficult operational environment for a waste collection truck is at the landfill itself. Judging by the extensive resale market for waste collection vehicles, a properly maintained truck can expect an extensive operational lifetime (often for more than a decade or two). But as the saying goes: “It ain’t the years, it’s the mileage.”

Typical capital costs vary with the type of waste collection vehicle being acquired. Standard vehicles managing commingled municipal solid waste can cost from $110,000 to $140,000 per truck for manual rear loaders or $115,000 to $140,000 per truck for mechanically operated front loaders and side loaders. Recycling trucks with the standard four separate waste compartments can run from $120,000 to $140,000 per truck (all costs from Handbook of Solid Waste Management, Kreith and Tchobanoglous, 2002; with costs adjusted to the Engineering News Record Construction Cost Index of 6,500).

The operations and maintenance costs can vary considerably, depending on the length of the collection routes, the number of stops made along the route, and the tonnage collected on each route. It isn’t the continuous running of the truck that causes wear and tear; it’s the repetitive stops and starts required by waste collection operations. These are what wear down the brakes, transmission, et cetera. Annual O&M costs are measured in terms of dollars per ton each year. Operating costs also include the labor costs associated with the driver and the loaders (for non-automated collection vehicles). Typical O&M costs for collecting commingled municipal solid waste range from $50 to $70 per ton. Being more labor intensive with the handling requirements for multiple wastestreams, the collection of source-separated recyclable materials can vary from $100 to $140 per ton.

There is an old saying in the waste industry that “You don’t make money picking waste up; you make money by putting it back down again.” Given the labor-intensive requirements of waste collection operations (even with automated loaders) versus the capital-intensive requirements of landfill construction and operations, it is easy to see why this is so. The costs of collecting and hauling wastes can be determined in a relatively straightforward manner (e.g., truck miles or labor hours) and vary mostly with population density. The more densely populated the area being serviced by a waste collection vehicle fleet, the lower the O&M costs due to less wasted transit time spent traveling between stops. Operations at the landfill where the waste is disposed are unique in that they combine relatively high upfront capital costs (associated with permitting and constructing the landfill itself) and relatively low operating costs. Therefore, it is often best to treat the two operations as separate cost centers for the purposes of accounting.

Major Makes and Models
One of the biggest names in heavy-duty trucks, Mack Trucks, has an extensive line of waste collection vehicles. The design of its TerraPro Series is based on the successful MR and LE Series, with an emphasis on operator comfort and ergonomically designed workflow to maximize productivity. The flexible design of the TerraPro Series can accommodate front-loader, side-loader, and rear-loader applications. Equipped with a diesel particulate filter, the TerraPro series runs cleaner than its predecessors. The TerraPro Cabover model is the industry’s leading seller and is augmented by the versatile Low Entry model. Designed for rugged use, the Cabover optimizes maneuverability with a small turning radius. It comes equipped with a 300-horsepower engine delivering more than 1,200 foot-pounds of torque to an eight-speed transmission.

Mack’s Low Entry waste collection vehicle is the result of comprehensive customer research and engineering redesign of traditional waste collection concepts. Its design combines an in-cab control Link with a back-of-cab body link system serving as quick connection, bodybuilder interfaces. This allows for flexibility in body installation, allowing for the use of side-loader or rear-loader systems. Its 300-horsepower engine delivers over 1,200 foot-pounds of torque to a six-speed transmission.

In an industry dedicated to protecting human health and the environment, it’s surprising that more manufacturers don’t “go green.” Well that is exactly what Volvo has done with its new Volvo FE Hybrid waste collection vehicle. Volvo plans to put this newly developed diesel-electric hybrid into full production later this year. Waste collection vehicles constantly stop and start as they make their way around collection routes. In doing so, they become big wasters of fuel as they sit around idling while the waste is being loaded. Volvo’s simple hybrid design includes a 320-horsepower diesel engine with a 120-kW lithium-ion electric battery and motor. The electric motor can power the truck up to speeds of 12 miles per hour and will receive energy recharges every time the truck hits its brakes. Initial estimates indicate that the new trucks will use 20% less fuel with a proportional reduction in emissions.

In step with Volvo is Peterbilt’s (a division of PACCAR Inc.) new hydraulic hybrid Model 320 HLA, equipped with hydraulic launch assist (HLA) technology developed by the Eaton Corp. HLA works by recovering up to 75% of the energy normally lost to waste heat while braking. This system captures braking energy and stores it as pressurized hydraulic fluid in an onboard accumulator, instead of an eclectic battery. The fluid is then used to help propel the truck when the driver gets it back under way. Not only can the compressed fluid drive the vehicle at low speeds, it can also provide an 18% improvement in acceleration efficiencies. Early estimates indicate that the reductions in emissions and fuel consumption by the Model 320 are significant. Furthermore, the use of a hydraulic hybrid system results in a 50% reduction in annual brake realignment maintenance requirements. “The Model 320 HLA is an ideal environmental option for refuse applications,” says Bill Jackson, Peterbilt general manager and PACCAR vice president. “Dramatic improvements in fuel economy, reductions in emissions, and lower maintenance costs spotlight the Peterbilt Model 320 Hydraulic Hybrid as the environmentally responsible, fuel-efficient solution for municipal and residential solid waste transportation fleets. These fleets operate in some of the most demanding of truck applications, often making 800 to 1,200 stops per day on collection routes.”

Peterbilt’s traditional Model 320 is ergonomically designed for driver comfort. A removable three-frame cross-member allows for ease of service. Power trains are available in either front-mounted or transmission-driven configurations. Optional frame liners are available for heavier applications (like hauling concrete and bric-a-brac from construction-and-demolition debris. It offers a full range of axle selections in single, tandem, or tri-drive configurations, plus a full complement of tag and pusher axle option. The Model 320 is available in a variety of configurations with a full range of options for the refuse, construction, and inner-city hauling markets. It comes equipped with a 306- to 470-horsepower engine delivering power to an 8- or 13-speed transmission. The various combinations of options allows for customized applications for specific operations.

International’s Durastar waste collection vehicles are designed and built for simplicity and endurance with minimal downtime. The integrated wiring design of its Diamond Logic electrical system utilizes 40% less wiring than standard waste truck electrical systems. This reduces the need for maintenance and the potential for repair. Well-planned, synchronized service intervals further reduce maintenance costs. Durastar’s MaxxForce DT engine provides up to 9% to 13% improvement in fuel economy. This fuel-injected V6 engine provides the industry’s best combination of horsepower and torque.

Freightliner’s Business Class M2 series of waste collection trucks provides flexible configurations based on four models. These trucks are designed to support a wide variety of bodies and chassis-mounted equipment. This can come with MBE900 engines that can deliver up to 350 horsepower, and with wheelbases that provide a tight 55-degree wheel cut for ease of maneuverability. The MS models can come with either manual or automatic transmissions from Mercedes-Benz, Eaton Fuller, or Allison, along with Freightliner’s Smart Shift option. The multiplex wiring system reduces the number of wires by nearly 50%, and comes with color-coding and ServiceLink diagnostic tools for ease of maintenance and repair. The most versatile of these models is the M2 106V, providing front engine power-train operation housed in front frame extensions. These frame extensions come in increments of 6 inches, 12 inches, or 24 inches.

The Crane Carrier Corp. (CCC) provides both a packaged front loader (PFL) and a packaged side loader (PSL) model waste collection vehicle. Utilizing a Cummins ISC-260 engine delivering 258–800 horsepower to an Allison transmission, the PSL model carries waste storage bodies ranging in size from 25 cubic yards to 37 cubic yards. It is built on the company’s standard low-entry tilt chassis.

As the only ISO 9000–certified domestic refuse body manufacturer in America, Heil provides a full range of refuse collection vehicles (front loaders, rear loaders, side loaders, and recyclers). Its front loaders come with a patented clamp-on arm that reduces maintenance by 70% and comes standard on its Half Pack and Half Pack Sierra front loaders. The Sierra is a lightweight version of the standard Half Pack, with all of the features and performance characteristics of the Half Pack but with 13% less gross body weight. The 40-cubic-yard Half Pack Sierra weighs just 16,700 pounds versus 19,300 pounds for the same size standard Half Pack body. Both bodies offer payloads up to 1,200 pounds per cubic yard, a packer cycle time of 22 to 26 seconds, and arm cycle times of 18 to 20 seconds. Rear loaders are represented by Heil’s Formula series trucks (4000, 4060 SB, and 5000). They come in a variety of sizes from 11 to 32 yards, with an optional narrow body version also available. The SB is a split-body model with a dual tailgate refuse or recycling rear loader. It has separate compartments and independent unloading capability.

A greater diversity is provided in Heil’s side loaders. The original Square Body is the loader designed for Class 7 and Class 8 tucks ranging in size form 18 to 33 cubic yards. The Durapack is a high-compaction version with somewhat higher capacity ranging from 26 to 33 yards. With its exceptionally long-reach arm, Heil’s Rapid Rail is the company’s original model automated side loader. The Starr system is a trailer version of the Rapid Rail with a very small turning radius, and the Co-Collector is a split-body version. For designated routes where full-size collection vehicles cannot go (small alleys and narrow roads), Heil has its Retriever class of small side loaders. For recycling application, Heil provides the Recycle 2000. With its two-commodity compaction recycling body for tandem trucks, it is loaded from side-mounted buckets.

McNeilus, a manufacturer of concrete trucks as well as refuse trucks, provides a complete ensemble of rear, front, and side loaders. The company’s front loaders come in the matched Atlantic and Pacific models. The Atlantic has AR-450 abrasion-resistant sidewalls and an arm capacity of 10,000 pounds. The Pacific is designed to meet tougher weight laws out on the West Coast. The company’s line of automated side loaders greatly increases waste collection operational efficiencies. A more flexible version is the Manual/Automated side loader that also allows for manual rear loading. The McNeilus Standard rear loader has a packing cycle of only 16 seconds, significantly increasing the speed of operations. The Tag Axle version has the rear axle built into the tailgate, creating better weight distribution to all three axles. The Heavy Duty version is suitable for large loads and commercial waste pickups. The XC Extra Compaction is the extreme limit of waste compaction capabilities, allowing for more tonnage per load of waste. The large-scale vehicles are augmented by the cost effective Metro-Pak and the smaller, more agile McNeilus M5.

Autocar LLC builds and supports Class 8 LCF refuse trucks. Running both on diesel and on natural gas, the Autocar E3 Advanced Hydraulic Hybrid Drive has the best overall strength-to-weight ratio in the industry. Equipped with a Cummins 345-horsepower engine that delivers 1,150 foot-pounds of torque, the E3 has a wide range of vehicle and body configurations. The company’s new E3 Hybrid stores energy from braking and provides 50% fuel savings and reduced emissions.

GS Products delivers a family of mobile solid waste and recycling equipment and highly specialized collection equipment, including its MP-8000 Sideloader, 6000 Side Dump, 5000 Top Loader, and 3000 End Dump. Based on proven design concepts and readily available parts, its goal is to produce durable, easy-to-maintain machines.
Natural Gas Vehicles (NGVs) for Your Waste Fleet?
Diesel-to-natural-gas engine conversions for waste collection and transfer vehicles have been around for two decades, but it hasn’t been until recently that they’ve begun to capture the attention of waste fleet managers, so you might ask, “Why now?”
There are a number of reasons, among which some leading candidates are:
• Environmental: Natural gas engines (NGEs) are inherently cleaner-burning than their diesel counterparts and are able to meet 2010 emissions requirements generally without the need for complex aftertreatment devices.
• Economics: NGV operating costs are equal to and perhaps less than their diesel counterparts, owing to prevailing fuel cost savings, reduced maintenance costs (principally exhaust aftertreatment system-related), and a variety of federal and other incentives designed to bring acquisition and ownership costs into line with diesel-powered vehicles.
• Public perception: NGEs are quieter (10 dB) than their diesel counterparts (which makes them more neighborhood friendly, particularly where local traffic ordinances encourage off-hour collection and transfer activities), are thought to be “greener” in matters beyond the environmental realm, and provide an antidote to our reliance on foreign oil.
There are other reasons as well—resource availability (proven reserves), gas delivery infrastructure, renewable resource augmentation (LFG/biomethane), and decreasing costs of fueling systems—but the main reason for their emergence lies in the heavy investment and leadership on the part of engine suppliers such as Cummins Westport, vehicle manufacturers such as McNeilus, Autocar, E-Z Pack, Crane Carrier, Mack, and Peterbilt, and fueling infrastructure providers such as Clean Energy.
The Cummins Westport ISL G is an 80% common version of its 8.9-liter diesel workhorse. Principal differences lie in its valve train (two rather than four valves per cylinder), cylinder head design (compression ratio and combustion chamber), and fuel delivery system (manifold versus common rail injection). Variants of the basic engine deliver from 250 to 320 horsepower and from 600 to 1,000 foot-pounds of torque while emitting 0.2 gm/bhp-hr NOx and 0.01 gm/bhp-hr particulates.
McNeilus has delivered NGVs to a number of fleets throughout the country, including the city of Long Beach CA, V. Garofalo Carting at Brentwood NY, CleanScapes at Seattle, WA, and most recently the city of Chicago, where it has delivered 20 units.
“Our entire collection fleet has McNeilus bodies,” reports Vernon Helbig, superintendent of maintenance for the city of Long Beach. “All of our side loaders are NGVs with Cummins engines, and we’re in the process of converting our rear loaders as well. We’ve found that the natural-gas engines require considerably less maintenance than diesel.”
E-Z Pack Manufacturing, LLC, is in the process of delivering 10 new CNG-powered Hercules ASL trucks to Choice Environmental Services Inc., in Fort Lauderdale, FL. E-Z Pack’s CNG side loader is unique because it features onboard CNG fuel cells integrated into the body in addition to the standard chassis mounted fuel tanks.
Autocar—With more than 500 natural-gas Xpeditors on the road, Autocar has established itself as a leading supplier of LCF Class 8 natural gas refuse trucks. Recently the company delivered 102 NGVs to the City of Seattle and is currently working with Sunnyvale CA-based Specialty Solid Waste and Recycling (SSWR) to replace 30 of its 37 refuse haulers with Xpeditor NGVs.
Clean Energy—With no leasing agreements, access fees, or capital outlay for the city, Clean Energy provides the fueling infrastructure to support Smithtown, NY’s CNG-fueled waste haulers at a starting price of $2.33 per diesel gallon equivalent (DGE), increasing to $2.95 per DGE in 2013. Clean Energy is currently constructing a fueling station to support the Choice Environmental fleet in Fort Lauderdale.
About the Author

Daniel P. Duffy

Daniel P. Duffy, P.E., writes frequently on the topics of landfills and the environment.

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