title: Anaerobic treatment of antibiotic production wastewater pretreated with enhanced hydrolysis: Simultaneous reduction of COD and ARGs.
abstract: The presence of high concentration antibiotics in wastewater can disturb the stability of biological wastewater treatment systems and promote generation of antibiotic resistance genes (ARGs) during the treatment. To solve this problem, a pilot system consisting of enhanced hydrolysis pretreatment and an up-flow anaerobic sludge bed (UASB) reactor in succession was constructed for treating oxytetracycline production wastewater, and the performance was evaluated in a pharmaceutical factory in comparison with a full-scale anaerobic system operated in parallel. After enhanced hydrolysis under conditions of pH 7 and 85 °C for 6 h, oxytetracycline production wastewater with an influent chemical oxygen demand (COD) of 11,086 ± 602 mg L-1was directly introduced into the pilot UASB reactor. With the effective removal of oxytetracycline and its antibacterial potency (from 874 mg L-1to less than 0.61 mg L-1and from 900 mg L-1to less than 0.84 mg L-1, respectively) by the enhanced hydrolysis pretreatment, an average COD removal rate of 83.2%, 78.5% and 68.9% was achieved at an organic loading rate of 3.3, 4.8 and 5.9 kg COD m-3d-1, respectively. At the same time, the relative abundances of the total tetracycline (tet) genes and a mobile element (Class 1 integron (intI1)) in anaerobic sludge on day 96 were one order of magnitude lower than those in inoculated sludge on day 0 (P < 0.01). The reduction of ARGs was further demonstrated by metagenomic sequencing. By comparison, the full-scale anaerobic system treating oxytetracycline production wastewater with an influent COD of 3720 ± 128 mg L-1after dilution exhibited a COD removal of 51 ± 4% at an organic loading rate (OLR) 1.2 ± 0.2 kg m-3d-1, and a total tet gene abundance in sludge was five times higher than the pilot-scale system (P < 0.01). The above result demonstrated that enhanced hydrolysis as a pretreatment method could enable efficient anaerobic treatment of oxytetracycline production wastewater containing high concentrations of oxytetracycline with significantly lower generation of ARGs.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Qizhen
authors.initials: Q
authors.lastname: Yi
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: zhangyu@rcees.ac.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Post Office Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D000693:Anaerobiosis; D000900:Anti-Bacterial Agents; D019149:Bioreactors / Q000382:microbiology; D006868:Hydrolysis; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D062065:Wastewater
keywords: Anaerobic treatment; Antibacterial potency; Antibiotic resistance; Hydrolysis pretreatment; Oxytetracycline production wastewater