Page 143 - Materials Chemistry, Second Edition

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114 Waste Management Practices: Municipal, Hazardous, and Industrial
TABLE 5.2 (continued)
Loading Height Speed
The lower the loading height, the more easily solid waste Vehicles should perform well at a wide range of speeds
can be loaded into the truck. If the truck loading height is Design Considerations
too high, the time required for loading and the potential • Distance to disposal site
of injuries to the crew members will increase because of • Population and traffic density of an area
strain and fatigue • Road conditions and speed limits of routes that will be
used
Design Considerations
• Weight of full solid waste containers Adaptability to Other Uses
• If higher loading height is being considered, consider Municipalities may wish to use solid waste collection
an automatic loading mechanism equipment for other purposes such as snow removal

Source: Pferdehirt, W., 1994. Reproduced with kind permission of W.P Pferdehirt, University of Wisconsin-Madison.

Additionally, certain cost data should be compared for each truck being considered, including initial
capital cost, annual maintenance and operation costs, and expected service life (U.S. EPA, 2003).
If the number of households that a truck can service in a single day has been determined, the
number of collection vehicles needed for a community can be estimated by the equation (Vesilind
et al., 2002)

N SF/XW (5.1)

where N is the number of collection vehicles needed, S the total number of households serviced, F
the number of collections per week, X the number of customers a truck can service per day and W
the number of workdays per week.

EXAMPLE 5.3
From the data for the town of Livengood (Example 5.1), determine the number of collection vehi-
cles needed if 8250 households must be serviced once per week. The trucks collect wastes 4 days
per week, with 1 day for routine truck maintenance and other projects.
We will assume that an average truck can service 1.4 households per minute. The actual time
spent collecting is 5 h. The total number of households served per day is

1.4/1 x/(5 h 60 min) 420 customers per day
N SF/XW

N 8250 1/420 4 4.9 trucks

5.3.8 DEVELOPING COLLECTION ROUTES

Thorough collection routes and schedules must be developed for the proposed collection program.
Efficient routing and rerouting of collection vehicles hold down costs by reducing the labor
expended for collection. Routing procedures usually comprise two separate components: micro-
routing and macrorouting (U.S. EPA, 2003). Macrorouting consists of dividing the total collection
area into routes of a size sufficient for a 1 day collection for a single crew. The size of a route is a
function of the amount of waste collected per stop, distance between stops, loading time, and traf-
fic conditions. Barriers such as railroad embankments, rivers, and roads with heavy competing traf-
fic can be used to divide route areas.