Fig. 4(b) shows the changes in thermophilic bacteria biomass. We can see thermophilic bacteria biomass in DHAF ishigher than in TSC by almost three orders of magnitude under the temperature of 53–59 C, which is the symbol of intense microbial activity.
The reason can be attributed to aeration, friction and collision. In order to find the relationships between microbial activity and aeration, friction, collision, an investigation to compost particle was carried out as follows.