96 Organic waste recycling: technology and management
declines, members of the actinomycetes become the dominant group which may
give the heap surface a white or grey appearance.
Figure 3.3 Food web of the compost pile (Dindal 1978; reproduced by permission of the
JG Press)
Thermophilic bacteria mostly Bacillus spp. (Strom 1985), play a major role in
the decomposition of proteins and other carbohydrate compounds. In spite of being
confined primarily to the outer layers of the compost piles and becoming active
only during the latter part of the composting period, fungi and actinomycetes play
an important role in decomposing cellulose, lignins and other more resistant
materials, which are attacked after the readily decomposed materials have been
utilized. The common species of actinomycetes are reported to be Streptomyces
andThermoactinomyces, while Aspergillus is the common fungus species (Strom
1985).
After these stages, the first level consumers become the food for second level
consumers such as mites, beetles, nematodes, protozoa and rotifers. Third level
consumers such as centipedes, rove beetles and ants prey on the second level
consumers. A schematic diagram showing the growth patterns of different level
consumers with composting time and temperature is presented in Figure 3.2.