纳米氧化铜颗粒和环丙沙星对好氧颗粒污泥的协同胁迫效应

纳米颗粒和抗生素在污水处理厂中的共同存在可产生综合毒性.选择纳米氧化铜颗粒(CuO NPs)和环丙沙星(CIP)作为纳米颗粒和抗生素的代表性物质,探究了CuO NPs和CIP共存胁迫对好氧颗粒污泥(AGS)系统的运行性能、污泥特性和微生物群落的长期影响.结果表明:CuO NPs单独胁迫使脱氮性能轻微提高,对碳和磷的去除性能轻微下降.CIP单独胁迫显著抑制了碳、氮和磷的去除性能.CuO NPs和CIP共存时对碳、氮和磷去除表现出明显的协同抑制效应.CuO NPs和CIP共存胁迫使细胞膜完整性下降,乳酸脱氢酶(LDH)释放量增多,胞外聚合物(EPS)分泌增强,且溶解性EPS(S-EPS)的官能团发生显著变化.CuO NPs和CIP共存胁迫改变了微生物群落结构,对生物多样性具有显著的协同抑制效应,对微生物具有较强的毒性作用.

Synergistic stress effect of copper oxide nanoparticles and ciprofloxacin on aerobic granular sludge

The coexistence of nanoparticles and antibiotics in wastewater treatment plants can produce combined toxicity. CuO NPs and CIP were used as representative substances of nanoparticles and antibiotics, respectively, to investigate the long-term coexistence effects of CuO NPs and CIP on the operation performance, sludge characteristics and microbial community in aerobic granular sludge (AGS) systems. The nitrogen removal under CuO NPs single stress slightly improved. Meanwhile, the carbon and phosphorus removal slightly decreased in the AGS system. CIP single stress significantly inhibited the removal of carbon, nitrogen and phosphorus. The coexistence stress of CuO NPs and CIP showed an obvious synergistic inhibition on the removal of carbon, nitrogen and phosphorus. The coexistence stress of CuO NPs and CIP decreased cell membrane integrity, increased lactate dehydrogenase (LDH) release, enhanced extracellular polymeric substances (EPS) secretion, and significantly changed the functional groups of soluble EPS(S-EPS) in AGS systems. The coexistence stress of CuO NPs and CIP changed microbial community structure, had a significant synergistic inhibition on biodiversity, and had a strong toxicity on microorganisms.