Geography Reference
In-Depth Information
This is the same amount of time used by Arribas et al.
2010.(Anecdotal evidence would indicate that this collection time is
actually much longer with some smaller companies due to trucks that
do not compact waste efficiently or a single employee doing both
driving and collecting of solid waste.) According to workers at the
local transfer stations, the amount of time spent unloading a full truck
varies between 5-15 minutes depending on the number of other trucks
present. This research uses an average time of 10 minutes for each
visit to the transfer station.
solid waste collection truck size
-the size of each company's solid
waste collection truck varies from the smallest of a 2cubic yard loader
to the largest of 25 cubic yards. Varying sizes of 11, 12, 14, and 20
cubic yard loaders also exist. Because so few companies were willing
to cooperate when contacted, the size of each hauler was visually
estimated and placed into one of three size categories:
Mini - 4 cubic yard loader = 1.0 tons (2,000 lbs) of solid waste
Mid - 12 cubic yard loader = 4.5 tons (9,000 lbs) of solid waste
Large - 25 cubic yard loader = 10.5 Tons (21,000 lbs) of solid
waste
Based on solid waste hauler size and amount of solid waste per household,
the approximate number of households each can collect prior to capacity is 40
houses for a mini-hauler, 180 houses for a mid-hauler, and 420 houses for a
large hauler.
3.1. Vehicle Routing Problem
These data and methods were used in conjunction with the VRP to assess
the current collection system and also propose more efficient collection
scenarios. Figure 3 illustrates of a layout of the VRP model as it relates to
solid waste collection within the city. Even though some companies utilize
more than one truck to collect solid waste, this research models one collection
truck per company on each collection day. Three separate collection scenarios
for the City of Altoona were modeled: current collection, controlled collection,
and improved efficiency. The current collection scenario models all 20
independent companies as they collect solid waste on each of the four
collection days.
