ADVANCED SOLID WASTE MANAGEMENT UNIT IV

(0 'tors tion -age iges the uck md

'liel is

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tvl 11loisl1lll' l 0111,'111, W '[ basts, oil) w=ini(iHl(w('I)W'j ht ( sarnpl d = final ( Ily) wciaht f ample

SOI1l ngineers d fIn 'Ill isture content on a dry weight basis as

w - d Md=-d-X 100

where Md = moisture content on a dry basis, %. This relationship seems at first irrational, because the moisture content can

exceed 100%, but in some fields, such as geotechnical engineering, moisture con- tent on a dry basis is useful. In this text, moisture is always expressed on awet basis unless otherwise indicated.

Drying is usually done in an oven at 77°C (170°F) for 24 h to ensure com- plete dehydration and yet avoid undue vaporization ofvolatile material. The mois- ture content of various refuse components varies widely, as shown in Table 2-6,

The moisture content of anywaste can be estimated by knowing the fraction of various components and using either measured values of moisture content or typical values from a list (such asTable 2-6). This calculation is illustrated in Example 2-2.

Table 2-6 Moisture Content of Uncompacted Refuse Components

Moisture Content

Component

Residential Aluminum cans Cardboard Fines (dirt, etc.) Food waste Glass Grass Leather Leaves Paper Plastics Rubber Steel cans Textiles Wood Yard waste

Commercial Food waste Mixed commercial Wood crates and pallets Construction (mixed)

Range Typical

2-4 4-8 6-12

50-80 1-4

40-80 8-12

20-40 4-10 1-4 1-4 2-4 6-15

15-40 30-80

3 5 8

70 2

60 10 30 6 2 2 3 10 20 60

50-80 10-25 10-30 2-15

70 15 20 8

Source: [20based on 21J