Biodegradation and Adsorption of Antibiotics in the Activated Sludge Process

• Published in: Environmental science & technology Vol. 44; no. 9; pp. 3468 - 3473
• Main Authors: Li, Bing, Zhang, Tong
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-05-2010
• Subjects: Adsorption; Anti-Bacterial Agents - chemistry; Antibiotics; Applied sciences; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Bioremediation; Biotechnology; Cations; Environment and pollution; Environmental science; Exact sciences and technology; Fluoroquinolones - chemistry; Fresh water; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Kinetics; Magnesium - chemistry; Mass Spectrometry - methods; Other wastewaters; Pollution; Remediation and Control Technologies; Saline water; Sewage; Sludge; Time Factors; Waste Disposal, Fluid - methods; Wastewaters; Water Pollutants, Chemical - analysis; Water Purification; Water treatment and pollution; Hong Kong; Asia; China; Biodegradation; Drug; Activated sludge; Sulfonamide; Biodegradability; Operating conditions; Biological purification; Salinity; Hydrolysis; Persistence; Antibiotic; Adsorption; Batchwise; Volatilization; Micropollutant; Urban waste water; Kinetics; Waste water purification; Organic compounds
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es903490h

The removal of 11 antibiotics of 6 classes, that is, two β-lactams (ampicillin and cefalexin), two sulfonamides (sulfamethoxazole and sulfadiazine), three fluoroquinolones (norfloxacin, ofloxacin, and ciprofloxacin), one tetracyclines (tetracycline), two macorlides (roxithromycin and anhydro-erythromycin), and one others (trimethoprim), in activated sludge process was investigated using two series of batch reactors treating freshwater and saline sewage respectively. At environmental relevant concentrations tested in this study, biodegradation and adsorption were the major removal routes for the target antibiotics, where volatilization and hydrolysis were neglectable. Among the 11 target antibiotics, cefalexin and the two sulfonamides were predominantly removed by biodegradation in both freshwater and saline sewage systems. Ampicillin, norfloxacin, ciprofloxacin, ofloxacin, tetracycline, roxithromycin, and trimethoprim were mainly removed by adsorption. Divalent cations (Ca2+ and Mg2+) in saline sewage significantly decreased the adsorption of the three fluoroquinolones onto activated sludge. These three fluoroquinolones also exhibited certain biodegradability in the saline activated sludge reactor. Erythromycin-H2O was persistent in both saline and freshwater systems under the experimental conditions and could not be removed at all. Kinetics study showed that biodegradation of cefalexin, the two sulfonamides and the three fluoroquinolones followed first-order model well (R 2: 0.921−0.997) with the rate constants ranging from 5.2 × 10−3 to 3.6 × 10−1 h−1.