Simultaneous removal of triclosan and nitrate by a stable denitrifying microbial consortium

The co-existence of antibiotics and nitrate in common in the aquatic environment, so the simultaneous removal of antibiotics and nitrate is necessary, but still challenge. In this study, a stable denitrifying microbial consortium capable of degrading triclosan was isolated from a long-term operated denitrifying bioreactor used for biological nitrate removal. The microbial consortium consisted of Pseudomonas (93.47 %), Burkholderia (1.56 %) and Cupriavidus (1.17 %) based on high-throughout sequencing analysis. The denitrification efficiency was higher under anoxic condition than that under aerobic condition . However, the accumulation of nitrite was observed under anoxic condition, with maximal concentration of 10.2 mg/L. Triclosan had negative impact on denitrification under both aerobic and anoxic conditions. The pseudo first-order kinetic constant of denitrification was 0.0303 h −1 and 0.0468 h −1 under aerobic and anoxic conditions, respectively. Dechlorination of triclosan was observed under aerobic condition but not under anoxic condition. Hydroxylated-triclosan, 2,4-dichlorophenol and phenol were identified as intermediate products of triclosan degradation.