An appropriate temperature and thermophilic phase are necessary for FW composting. Many previous studies attempted to use quick external heating equipments, but seldom obtained satisfactory
results. This is because the rapid temperature increase by external heating might not be beneficial for microorganism growth. Different responses of microorganism to the changing
temperature can dramatically affect the performance of FW composting. In a typical self-heated FW composting process, temperature is gently increased along with the microbiological activity
of aerobic microorganism; it then drops under anaerobic environment when the pH reaches a certain level. Mesophilic microbes thus obtain a more suitable growing temperature, and finally
mature the remaining OM in a short period. In general, the selfheated composting provides a favorable thermophilic range (55–60 C) in a suitable period, and thus is necessary for the growth of both thermophilic and mesophilic microorganism. In quick external-heated composting, however, temperature always keeps in a certain level; the thermophilic microbes decrease with the increasing pH and decreasing oxygen concentration, but mesophlic microbes could not be active under such a high temperature. Therefore, quick external-heated composting can hardly provide a suitable temperature variation for supporting the succession of various microbial communities, and thus generate satisfactory composting performance.