Page 336 - Materials Chemistry, Second Edition

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The Sanitary Landfill 307

Density

FIGURE 10.9 Density of MSW in
a landfill cell as related to the number
of passes by machinery over the
waste. (From Vesilind et al., Solid
Waste Engineering, 1st ed., © 2002.
0
1 2 3 4 5 6 7 8 9 10 Reproduced with kind permission of
Number of passes made with each steel Brooks/Cole, a division of Thomson
wheel, rubber tire, or track Learning:www.thomsonrights.com.)

The above value, however, should be increased by about 50% to allow for use of daily cover, final
cover, receiving areas, roads, fencing, and other structures.

Required land area for 25 years 0.7 ha 25 years 1.5
26.25 ha or 64.8 acres

In the above example, what is the daily waste generation rate per capita? How does this figure com-
pare with the estimated national average (Chapter 1)?

10.4.14.2 Cover Materials
At the end of each operating day, active landfill cells must be covered with at least 6 in. of soil or sim-
ilar material to control disease vectors, fires, odors, blowing litter, and scavenging by animals (40 CFR
Part 258.21) (Figure 10.10). More frequent application of soil may be required if a specific nuisance
or hazard condition occurs at the facility, for example, strongly malodorous or gas-producing wastes.
In some instances local soil may not be readily available as a cover material; therefore, alter-
native materials may be required. The alternative material must be shown to control all relevant haz-
ards and nuisances (disease vectors, fires, and odors). Alternative cover materials may be natural or
commercially produced and must not pose a threat to human health and the environment. Some use-
ful materials are those that may be considered waste; therefore, using these materials is an efficient
use of landfill space. Examples of alternative materials include (U.S. EPA, 1992b):

● Fly ash and bottom ash from utilities and municipal waste incinerators
● Composted MSW or sewage sludge
● Foundry sands
● Yard waste (lawn clippings, leaves, and tree branches)
● Construction and demolition debris
● Shredded automobile tires
● Some commercially available cover materials include:
Foam that is sprayed onto the working face
Slurry products (e.g., fibers from recycled newspaper and wood chip slurry)
(U.S. EPA, 1992b).

Some of the commercial alternatives may require specially designed application equipment.