At the phylum level, proteobacteria were dominant in 60–70% of all treatments, including the control group. In the control group, Bacteroidetes increased with time and reached more than 30% abundance at eight days, while the abundance in KBM-1 and BM-S-1 treatments increased by approximately 25%. In the case of Firmicutes, there was no difference between the control and the treatments regardless of the treatment period length, and fusobacteria almost disappeared after eight days (Fig. 6). At the genus level, Acinetobacter, Bacteroides, Citrobacter, Comamonas, and Arcobacter were dominant in all treatments after eight days (Fig. 6). Acinetobacter decreased significantly in the KBM-1 treatment, while Citrobacter tended to increase two-fold.Comamonas sp. was one of the dominant genera in all treatments after eight days. This genus can contain denitrifying microorganisms.In fact, the levels of nitrate-N in the treatments with KBM-1 and BM-S-1 both decreased by 50% after eight days as opposed to that of the control (28%), indicating potential denitrification activity of Comamonas sp.In the KBM-1 treatment, Bacteroides graminisolvens showed approximately half the density of those in the other treatments after four days. The species was inhibited by treatment with KBM-1 (Fig. 6). As the treatment period progressed from four to eight days, the species density tended to decrease overall, but some species increased. The Escherichia coli group showed a two- tofour-fold decrease, while Citrobacter freundii decreased in the control and BM-S-1 treatment but increased in the KBM-1 treatment. The densities of Bacteroides graminisolvens, Comamonas jiangduensis, and Arcobacter defluvii, which increased after eight days, were two to three times higher than those of the four-day treatment. Comamonas jiangduensis can act as a denitrifier. Here, the density of Bacteroides graminisolvens in the control group was approximately 12% lower than that in the KBM-1 and BM-S-1 treatments.However, the facultative anaerobes (Sporolactobacillus inulinus, Lactobacillus mali, and Lactobacillus casei comprising 32% of the total communities) and the obligate anaerobe (Clostridium tyrobutyricum, 9%) identified from the active culture of KBM-1 were hardly detected in the solid waste treated with KBM-1.After four days, the highest values of α-diversity indices (OTUs, Chao1, Jackknife, and Shannon) were observed in the KBM-1 treatment, while the lowest were in the BM-S-1 treatment. The highest values of α-diversity indices were observed in the treatment of KBM-1 after eight days (Table 5).The results of the beta diversity of microbial communities in the solid waste treatment are shown in terms of UniFrac cluster analysis in Fig. 8. The BM-S-1 treatment and control were clustered in the same group after four days, but the KBM-1 treatment was grouped differently, indicating that the growth and adaptation of BM-S-1 were somewhat slow even after four days. The BM-S-1 and KBM-1 treatments grouped together after eight days, but the control was located differently.The reason for this appeared to be the formation of a specific group of microorganisms during the degradation of the solid waste by the inoculated microorganisms over time. Therefore, it was assumed that these microorganisms caused the differences in nitrogen removal and organic acid production abilities in the solid waste treatment.