28 Organic waste recycling: technology and management
reasons, food waste is normally collected together with other kinds of wastes to be
processed and treated at a solid waste treatment plant. If composting is to be
employed as a means to stabilize and produce fertilizer from the solid wastes,
several methods of solid waste processing have to be utilized to separate out the
food waste. These processing methods include mechanical size reduction and
component separation, the details of which can be found in the book Integrated
Solid Wastes Management (Tchobanoglous et al. 1993) and Handbook of Solid
Waste Management (Wilson 1977). The subject of composting is described in
Chapter 3 of this book.
Table 2.5 Comparative solid wastes analysisa
Thailand b Egypt c U.K d U.S.A e
Food wastes (organic) 63.6 70 17.6 9
Paper and card board 8.2 10 36.9 40
Metals 2.1 4 8.9 9.5
Glass 3.5 2 9.1 8
Textiles 1.4 2 2.4 2
Plastics and rubber 17.3 1 1.1 7.5
Miscellaneous, incombustible 3.2 10 21.9 4
Miscellaneous, combustible 0.7 1 3.1 20
Bulk density, kg/L 0.28 - 0.16 0.18
aunit in % wet weight
bhttp://www.mnre.go.th
cCook and Kalbermatten (1982)
dDepartment of Environment (1971)
eTchobanoglous et al. (1993)
2.2 ANIMAL WASTES
The amount and composition of animal wastes (feces and urine) excreted per unit
of time also vary widely. They depend on various factors such as the total live
weight of the animal (TLW), animal species, animal size and age, feed and water
intake, climate, and management practices, etc. For design of facilities for animal
waste collection and treatment, measurements and samples should be taken at the
farm site or (if the farm is not built) at similar sites. For planning purpose,
Taiganides (1978) suggests that the general guideline values given in Table 2.6
may be used. Young animals excrete more waste per unit of TLW than mature
animals. The quantities of wastewater or wastes to be handled would, in general, be
larger than those given in Table 2.6, due to the addition of dilution water,
washwater, moisture absorbing materials and litter, etc.