Page 123 - Materials Chemistry, Second Edition

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94 Waste Management Practices: Municipal, Hazardous, and Industrial

TABLE 4.22
Density and Moisture Content of MSW
3
Waste Source Component of Waste Density (kg/m ) Moisture Content (% by Wt)
Domestic Food 290 70
Paper products 70 5
Plastic 60 2
Glass 200 2
Metals 200 2
Clothing and textiles 60 10
Ashes, dust 500 8
Municipal Uncompacted 60–120 20
Baled waste 470–900 —
Compacted in collection truck 300–400 20
Compacted in landfill 300–890 25
Adapted from Vesilind, P.A. et al., Environmental Engineering, 2nd ed., Butterworths, Boston, MA, 1998.
Reproduced with kind permission of Elsevier Publishing.

A final disposal compaction ratio is calculated for landfills, and a compactor machine ratio is used
for equipment such as a baler, which is used to increase MSW density prior to disposal. A common
compaction ratio for a compacter machine may range from 2 to 4 (Sincero and Sincero, 1996).
If materials having different densities are expressed in terms of their weight fraction, the equa-
tion for calculating the overall bulk density is

(M M )
b
a
ρ (4.10)
M /P M /P (a b)
a a b b
where M is the mass of A, M the mass of B, ρ the bulk density of A and ρ the bulk density of B.
a
b
a
b
When there are more than two materials to be considered, the above equation is extended.
The degree of volume reduction that occurs as a result of waste compaction, whether in a baler
or landfill, is an important design variable. Waste volume reduction is calculated by the equation
(Vesilind et al., 2002)
V / V F (4.11)
o
c
where F is the fraction remaining of initial volume as a result of compaction, V the initial volume
o
and V the compacted volume.
c
EXAMPLE 4.6
For the following waste mixture,

Component % by Wt Uncompacted Bulk Density (kg/m )
3
Corrugated cardboard 25 30
Paper products 15 61
Aluminum 9 38
Food waste 29 368
Yard waste 22 7.1