title: Removal mechanisms for extremely high-level fluoroquinolone antibiotics in pharmaceutical wastewater treatment plants.
abstract: Pharmaceutical wastewater treatment plants (PWWTPs) receive industrial effluents from the plant that contain extremely high levels of antibiotics and are regarded as one of the major sources of antibiotics in the environment. Two PWWTPs have been selected in Zhejiang Province, China, to assess the removal mechanisms of fluoroquinolone antibiotics (FQs). PWWTP A uses activated sludge with biocarriers in a moving bed biofilm reactor in anoxic and aerobic units, and PWWTP B uses biological units under anaerobic, aerobic, and anoxic conditions. The wastewater samples and solid samples (sludge and suspended solid matter) were analyzed using solid-phase extraction and ultra-performance liquid chromatography-mass spectrometry. Ofloxacin (OFX) was detected in each stage of PWWTP A, and enrofloxacin and ciprofloxacin were detected in PWWTP B. The concentrations of FQs ranged from 0.32 μg/L to 5.7 mg/L. Although the FQs were largely removed in the biological units (94.5 to 99.9%), large amounts were still discharged in the final effluent (up to 88.0 ± 7.0 μg/L) and dewatered sludge (up to 0.85 ± 0.24 mg/kg). Mass balance analyses of samples from PWWTP A indicated that biodegradation (93.8%) was the major mechanism responsible for the removal of OFX, whereas the contribution of sorption by sludge (0.79%) was less significant, deviating from the findings of most similar studies. Using linear analysis and correlation analysis, we found that the log10values of the FQ concentration in the sludge were positively related with the log10values of the equilibrium concentration in water (Cw). These relationships can be described by a Freundlich-like equation. However, these relationships were negative when the Cwvalues were high. Our preliminary explanation is that the equilibrium Cwplays an important role in controlling the sorption behavior of FQs in activated sludge.
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China.|Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing, 210042, China.
authors.forename: Xinyan
authors.initials: X
authors.lastname: Guo
authors.affiliation: Chinese Society For Environmental Sciences, Beijing, 100082, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China.|Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing, 210042, China.
authors.forename: Xiangji
authors.initials: X
authors.lastname: Kong
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China.|Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing, 210042, China.
authors.forename: Deyang
authors.initials: D
authors.lastname: Kong
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China.|Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing, 210042, China.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Shan
authors.affiliation: Ministry of Environmental Protection, Nanjing Institute of Environmental Science, 8 Jiang-wang-miao Street, Nanjing, 210042, China. wangna@nies.org.|Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection of China, Nanjing, 210042, China. wangna@nies.org.
authors.forename: Na
authors.initials: N
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D001673:Biodegradation, Environmental; D002681:China; D002853:Chromatography, Liquid; D024841:Fluoroquinolones / Q000032:analysis*; D013058:Mass Spectrometry; D012722:Sewage / Q000737:chemistry; D052616:Solid Phase Extraction; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Antibiotics; Fluoroquinolone; Mass balance; Pharmaceutical wastewater treatment plants; Removal; Sorption