Performance and microbial community responses of the partial nitration process to tetracycline and Zn(II)

The feasibility of using the partial nitration (PN) process to treat wastewater containing tetracycline (TC) and Zn (II) was evaluated in this study. The community structure was analyzed using quantitative real-time PCR. The results suggested that the IC50 of TC and Zn(II) on the PN sludge were 235.8 and 41.8 mg L-1, respectively. The PN sludge was insensitive to TC at a relatively high concentration (<= 300 mg L-1) during the short-term exposure. Long-term test demonstrated that the PN sludge could tolerate 150 mg L-1 of TC after a domestication period. The PN performance was significantly inhibited when the concentration of Zn(II) reached 5 mg L-1. Real-time PCR revealed that the dynamics of the ammonia-oxidizing bacteria (AOB) were indicative for the operation of the PN process. The analyses also indicated that there was a direct correlation between the size of the indicative population and PN performance.