In a long-term FBC reactor, a problem that is likely to occur and which needs to be monitored is the significant abrasion of the bulking agents. Nagao et al. noted that both plastic bottle flakes and wood chips were capable of maintaining a high rate of decomposition. In addition, the bacterial community was examined by 16S rDNA clone analysis and the difference in the community between the two bulking agents was compared [15].

1.1.2 Small-Scale and Large-Scale Reactor

As mentioned above, a variety of bacterial community structures in various com­posting reactors have been reported. Nevertheless, knowledge of the microbial community in large-scale, completely-mixed composting reactors is still lacking. Therefore, this study was conducted to clarify the bacterial community succession during the start-up period of a large-scale, completely-mixed composting reactor by using 16S rDNA clone and DGGE analysis, and to compare it with the bacterial community in a small-scale reactor.