Section 6: SOLID WASTE PROCESSING AND
VOLUME REDUCTION CONVERSION
6.1 Solid Waste Processing Operations. Solid waste may be processed
manually, mechanically, or both for the purpose of separating and recover
materials from it, and to reduce the amount of material requiring disposa
at a sanitary landfill. Commonly used waste processing operations and th
benefits are summarized in Table 10.
The configuration of a mechanical solid waste processing system is
selected to achieve site-specific product specifications. A schematic
representation of a processing configuration is shown in Figure 7 to
familiarize the reader with typical system variations employed to recover
various solid waste-derived materials. As illustrated in the figure,
various degrees of processing and of material recovery are potentially
possible. In general, the greater the degree of processing, the greater
quality (i.e., lack of contamination) of the recovered materials, and the
higher the cost of equipment and operations.
The area required for a solid waste processing plant depends on a num
of factors, including the mass throughput rate, the degree of processing,
and storage requirements. As an example, the area of a building to house
the system schematically shown in Figure 7 would be about one fourth acre
(1000 square meters) for a plant with a throughput capacity of 100 tons (
metric tons) per day. Approximately one fifth of that area would be devo
to solid waste receiving and storage.
Diagrams of several of the unit processes described in this section a
shown in Figures 8 through 10.
6.1.1 Source Separation/Recycling. Source separation is the manual
segregation of solid waste into a disposable component, and a recyclable
component or components at the point of solid waste generation. The item
most commonly recycled through source separation are corrugated fiber,
newspaper, glass, steel cans, and aluminum beverage containers. In the c
of residential solid waste, the segregated recyclable items are collected
from individual households using collection vehicles (i.e., curbside
collection); alternatively, recyclable items are brought by individuals t
centralized recycling centers. Recycling centers may or may not offer
payment for materials taken to the center.
The quantities of materials and the number of segregated components a
generally the governing factors in the selection of the type of equipment
used in curbside collection programs. The type of equipment used in
curbside collection programs varies from commercially available collectio
vehicles to specially designed vehicles and container systems.
Materials collected at the curbside are generally taken to a centrali
location for processing and storage. At the centralized recycling center
separated items often require some processing (e.g., shredding and baling
to facilitate their transportation and to meet secondary material