Page 149 - Materials Chemistry, Second Edition

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120 Waste Management Practices: Municipal, Hazardous, and Industrial
Direct-discharge Noncompaction Stations
These stations are generally designed with two operating floors. In the transfer operation, wastes
are dumped directly from collection vehicles on the top floor through a hopper and into open-top
trailers on the lower floor. The trailers are often positioned on scales so that dumping is halted when
the maximum payload is reached. These stations are efficient because waste is handled only once.
However, some provision for waste storage must be provided at peak drop-off times or during sys-
tem interruptions.

Platform or Pit noncompaction Stations
In platform or pit stations, collection vehicles dump their wastes onto an area where wastes are
temporarily stored and sorted for recyclables or unacceptable materials. The waste is then
pushed into open-top trailers by front-end loaders (Figure 5.8). Platform stations are also con-
structed with two levels. Temporary storage is provided that can accommodate peak inflow of
wastes. Construction costs may be higher with this type of station because of the increased floor
space; however, the ability to temporarily store wastes results in a need for fewer trucks and
trailers. Also, facility operators can haul wastes at night or during other slow traffic periods
(U.S. EPA, 2003).
Compaction Stations
Compaction transfer stations use mechanical equipment to compact wastes before they are trans-
ferred. A hydraulically powered compactor is commonly used to compress wastes. Wastes are fed
into the compactor through a chute either directly from collection trucks or after storage in a pit.
The hydraulic ram pushes waste into the transfer trailer, which is mechanically linked to the com-
pactor. Compaction stations are used when (1) wastes must be baled for shipment (e.g., rail haul)
or for delivery to a balefill; (2) open-top trailers cannot be used because of size restrictions such as
viaduct clearances; and (3) the site layout does not accommodate a multilevel building conducive
to loading open-top trailers (U.S. EPA, 2003).

Transfer Station Design Considerations
The main objective in designing a transfer station should be to facilitate efficient operations. The
operating program should be as simple as possible; waste handling should be minimized and the

FIGURE 5.8 Pit-type noncompaction transfer station.