Seasonal dynamics of bacterial communities associated with antibiotic removal and sludge stabilization in three different sludge treatment wetlands

Abstract

In this study, antibiotics removal, sludge stabilization and the change in the bacterial community in sludge treatment wetlands (STWs) were investigated in different seasons. Pilot-scale STWs were characterized for sludge stabilization and the fate of antibiotics in surplus sludge applied during different seasons in three different configurations. The three configurations were unit S1 with ventilation, unit S2 with ventilation and reed plantings and unit S3 with reed plantings. The antibiotics used were ciprofloxacin, azithromycin and oxytetracycline and their degradation, degree of sludge stabilization and bacterial community dynamics were monitored. The results showed that the removal of antibiotics and reduction in the amount of organics in the planted units S2 and S3 were higher than those in the unplanted unit S1, especially in summer. The antibiotic removal efficiency in the planted unit S2, which was equipped with aeration tubes, was the highest over the entire test period. Bacterial community was analyzed by IlluminaMiSeq sequencing of the 16SrRNA gene, showed that the presence of plants in STWs enhanced microbial diversity and richness which promote the removal of antibiotics and sludge stabilization. Proteobacteria, Bacteroidetes and Firmicutes were dominant in the bacterial communities, with Thiobacillus, Dechloromonas and Pseudomonas occurring as dominant genera.