Page 148 - Materials Chemistry, Second Edition

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Municipal Solid Waste Collection 119
$30

Haul cost without
transfer station

"Break even"
Hauling cost, $/ton $20 point Haul cost with

station
$10 transfer
Transfer station
capital, operating,
and maintenance
cost
$0
0 10 20 30 40 50 60
Round-trip distance from waste source to disposal, (mile)

FIGURE 5.7 Comparison of waste hauling costs with and without a transfer station (U.S. EPA, 2002).
Assumptions used to create this sample comparison were as follows:
Cost to construct, own and operate transfer station ($/ton) $10
Average payload of collection truck hauling directly to landfill (tons) 7
Average payload of transfer truck hauling from transfer station to landfill (tons) 21
Average trucking cost (direct or transfer hauling) ($/mile) $3

5.3.12.1 Small to Medium Transfer Stations (capacity of less than 100 to 500 tons/day)

Small to medium transfer stations are usually “direct-discharge” facilities that provide little area for
interim waste storage. Such stations are equipped with operating areas for waste collection trucks
and are often provided with drop-off areas for use by the public. Direct-discharge stations are often
constructed with two operating floors. A compactor or open-top container is located on the lower
level. Users enter the upper level and dump wastes into hoppers attached to these containers.
Some smaller transfer stations used in rural areas may use simple drop-off collection, in which
a series of open-top containers are filled by users. The containers are then emptied into a larger vehi-
cle at the station or hauled directly to the disposal site. The number and size of containers at the facil-
ity depends on the size and population density of the area served and the frequency of collection.

5.3.12.2 Large Transfer Stations

Large transfer stations are designed for heavy commercial use by private and municipal collection
vehicles. When collection vehicles arrive at the site, they are checked in for billing, weighed, and
directed to the appropriate dumping area. Check-in and weighing procedures are often automated
for regular users. Collection vehicles travel to the dumping area and empty wastes into a trailer, pit,
or onto a platform. Transfer vehicles are weighed after loading to just under maximum legal
weights; this maximizes payloads and minimizes weight violations.
Several different designs for larger transfer operations are common depending on the transfer dis-
tance and vehicle type. Most designs fall into one of three categories: (1) direct-discharge noncom-
paction stations; (2) platform/pit noncompaction stations; or (3) compaction stations (U.S. EPA, 2003).