Page 122 - Materials Chemistry, Second Edition

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Characterization of Solid Waste 93

TABLE 4.21
Biodegradability of Selected Organic Components in MSW

Component Lignin Content (as % of VS) BF (as % of VS)
Food waste 0.4 0.82
Newsprint 21.9 0.22
Office paper 0.4 0.82
Cardboard 12.9 0.47
Yard waste 4.1 0.72
BF (Biodegradable fraction) 0.83 – (0.028) LC, where LC % of VS (volatile solids).
Source: Tchobanoglous, G. et al., Integrated Solid Waste Management: Engineering
Principles and Management Issues, McGraw-Hill, New York, 1993. Data reproduced
with kind permission of the McGraw-Hill Companies, Inc.

increase MSW density for long-distance transport, for example in rail cars. An upper limit of baled
3
3
density is approximately 900 kg/m (1500 lb/yd ) (Pfeffer, 1992). Values for waste density are shown
in Table 4.22.
EXAMPLE 4.5

During a sampling event at a tipping floor of a MRF, MSW is found to contain the following com-
ponents:

Component Density (kg/m ) Amount in Sampled Waste (% by Wt)
3
Food waste 290 22
Mixed plastics 60 12
Glass 200 8
Ferrous and aluminum 200 12
Textiles 60 5
Dust, dirt 500 28

What is the average density of this solid waste mixture?

SOLUTION

Average density (0.22)(290) (0.12)(60) (0.08)(200) (0.12)(200)
(0.05)(60) (0.28)(500)
254 kg/m 3

Efficient use of landfill volume is an essential parameter in landfill management. During routine
waste management operations (e.g., landfilling, tipping at a transfer station), trucks are weighed
when entering and exiting the facility. With knowledge of the compacted density, the volume of land
required at a landfill can then be calculated.
The density of MSW can be calculated on an as-compacted or as-discarded basis. The com-
paction ratio r is defined as the ratio of the as-compacted density ρ to the as-discarded density ρ
c d
and is given by

r ρ / ρ (4.9)
c d