Bioaerosolization behavior along sewage sludge biostabilization

Biostabilization is a cost-effective method for the beneficial utilization of sewage sludge. However, during the operation of sludge biostabilization, some microbial species could be released into the atmospheric environment from the solid-phase of sludge easily and present a high risk to human health. This study aimed to evaluate the risk of bioaerosol during sludge biostabilization. We found a total of nine bacterial phyla, one archaeal phylum, and two fungal phyla in the bioaerosol samples. Among them, Proteobacteria, Actinobacteria, Bacteroidetes, and Ascomycota were the dominant phyla. In addition, the bioaerosolization indexes (BI) of prokaryotic phyla and fungal phyla ranged 0–45 and 0–487, respectively. Massilia, Pseudarthrobacter, Pseudomonas, Tremellales spp., and Fusarium were the preferentially aerosolized microbial genera with maximum bioaerosolization indexes of 19962, 10360, 1802, 3055, and 7398. The bioaerosol concentration during the biostabilization ranged from 160 to 1440 cell/m, and we identified species such as Stenotrophomonas rhizophila and Fusarium graminerum with high bioaerosolization indexes that could be threats to human health. Euryachaeota, which belongs to archaeal phyla, had the highest biostabilization index in our study. We also found that Pseudarthrobacter was the easiest to aerosolize during the sludge biostabilization process.