October 2009

The Workhorses of Waste

Collection vehicles vary according to type and specification.

Article Tools

Create a Link to this Article
Refuse Truck

Photo: Mcneilus

By Daniel P. Duffy

Comments


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).

Advertisement

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. Next Page >

What Do You Think?

Post a Comment

Be the first to tell us what you think!

Post a Comment

Not a subscriber? Sign Up
 
 
*  
 




 

Get MSW Email Updates!

Get weekly news and updates through our MSW email newsletter!