Zhetai Hu,Peide Sun,Zhirong Hu,Jingyi Han,Ruyi Wang,Liang Jiao,Pengfei Yang
The effects of Erythromycin (ERY) and oxytetracycline (OTC), including individual and combinative effect, on enhanced biological phosphorus removal (EBPR) system within a short-term (24 h) were evaluated in this study. Results showed that the P-removal efficiency decreased to 34.6% and 0.0% under the effect of ERY (10 mg/L) and OTC (10 mg/L) for 24 h. OTC concentration higher than 5 mg/L was sufficient to cause serious adverse impact on the EBPR performance. While the performance of EBPR system will be impacted by ERY above 10 mg/L. OTC, due to its special antibacterial action to the gram-negative bacteria which most PAOs belong to, has more serious negative effect on the EBPR performance than ERY does. Moreover, in the combined antibiotics test, neither synergistic nor antagonistic effect was detected between ERY and OTC. Finally, ERY (10 mg/L) and OTC (10 mg/L) could inhibit the microorganisms’ activity, while couldn’t induce serious microorganisms death within 24 h.
Ligui Wu,Qiaofeng Wu,Jingcheng Xu,Lingling Rong,Xiaoli Yu,Chen Cai,Xiangfeng Huang,Xiaoming Zou
The effects of antibiotics on the proliferation of antibiotic resistant genes (ARGs) in WWTPs have drawn great attention in recent years. The effects of antibiotics on ARGs in the enhanced biological phosphorus removal (EBPR) system and its mechanisms, however, are still not well understood. In this study, EBPR systems were constructed using activated sludge to investigate the effects of ten commonly detected antibiotics in the environment on the proliferation of ARGs and the mechanisms involved. The results showed that the total abundance of ARGs increased to varying degrees with the addition of different antibiotics (0.05 mmol/L), and the top 30 ARGs increased by 271.1 % to 370.0 %. Mobile genetic elements (MGEs), functional modules, and the bacteria community were consistently related to the changes in ARGs. Refractory antibiotics, in particular, have a stronger promoting effect on transduction in the EBPR system. The insertion sequence common region (ISCR) and transposon (Tnp) were identified as crucial factors in the proliferation of ARGs. Moreover, the risk of polyphosphate accumulating organisms (PAOs) carrying ARGs in the presence of antibiotics should not be ignored. Our findings emphasize the potential efficacy of employing strategies that target the reduction of MGEs, regulation of cellular communication, and management of microbial communities to effectively mitigate the risks associated with ARGs.