Page 118 - Materials Chemistry, Second Edition

CAT3525_C04.qxd 1/27/2005 11:12 AM Page 89
Characterization of Solid Waste 89
● Hemicellulose
● Cellulose and lignocellulose
● Lignin
● Fats, oils, and waxes

4.5.6 CARBOHYDRATES
The main sources of carbohydrates are putrescible garbage and yard wastes. Carbohydrates are
designated by the general formula (CH O) and include a range of sugars and their polymers
2
x
such as starch and cellulose (Figure 4.8). Some polymers vary markedly in their resistance to
hydrolysis. The starch polymers readily hydrolyze to glucose (Figure 4.9), which is a water-sol-
uble and highly biodegradable simple sugar. Such polymers may therefore attract pests such as
flies and rats. Sugars account for 4 to 6% and starches 8 to 12% of the dry weight of MSW
(Pfeffer, 1992).

TABLE 4.20
Elemental Analysis of Organic Materials Used as Feedstock for Biological
Conversion Processes
Component Newspaper Office Paper Yard Waste Food Waste
K (%) 0.35 0.29 2.27 4.18
Ca (%) 0.01 0.10 0.42 0.43
Mg (%) 0.02 0.04 0.21 0.16
NH –N (mg/kg) 4 61 149 205
4
NO –N (mg/kg) 4 218 490 4278
3
SO –S (mg/kg) 159 324 882 855
4
P (mg/kg) 44 295 3500 4900
B (mg/kg) 14 28 88 17
Zn (mg/kg) 22 177 20 21
Mn (mg/kg) 49 15 56 20
Fe (mg/kg) 57 396 451 48
Cu (mg/kg) 12 14 7.7 6.9
Ni (mg/kg) — — 9.0 4.5

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.

CH 2OH H OH
H
O O
H OH H
OH H H
O O O
H H
H OH CH 2OH

FIGURE 4.8 General structure of a carbohydrate molecule.