规模化猪场废水处理过程中四环素类和磺胺类抗生素的降解特征

Characteristics of Degradation Tetracyclines and Sulfonamides During Wastewater Treating Processes in an Intensive Swine Farm

  • 摘要: 针对畜禽养殖场废水处理过程中抗生素的残留水平及其消减特征等问题,以苏南地区典型规模生猪养殖场为研究对象,探讨了冬季和夏季猪场废水处理各环节中四环素类(TCs)和磺胺类(SAs)抗生素的浓度及降解特征。结果发现,现有沼气工程进料浓度高,水力停留时间短,对土霉素(OTC)、金霉素(CTC)和强力霉素(DOX)的去除率分别为12.9%~69.3%、20.4%~60.9%和25.3%~55.0%,对磺胺嘧啶(SD)、磺胺二甲嘧啶(SM)和磺胺氯哒嗪(SCP)的去除率分别为13.8%~18.2%、46.8%~61.8%和18.1%~48.7%。冬季出料沼液中抗生素浓度远高于夏季,其中ρ(CTC)、ρ(SD)和ρ(SCP)平均值分别为0.887、0.492、和10.160 μg·L-1,直接还田存在生物安全风险。沼液后处理(如沉淀池和水生植物塘)对大幅降低沼液中TCs和SAs有积极作用,且夏季去除率(>90%)高于冬季,是沼液无害化处理和农田安全利用的重要措施。厌氧–好氧生物处理组合工艺是养殖废水中抗生素(特别是SAs)有效降解的重要手段。

     

    Abstract: Antibiotics and their metabolites are emerging contaminants posing a potential worldwide human health risk. Intensive animal husbandry is believed to be a major contributor to the increasing environmental burden of antibiotics. As to the antibiotics in animal manure in China, little information is available regarding characteristics of the degradation of antibiotics during wastewater treating processes in intensive animal husbandry. The aim of this study was to investigate concentrations of tetracyclines (TCs) and sulfonamides (SAs) types of antibiotics in wastewater and to explore their degradation characteristics during the processes of treating the wastewater in an intensive swine farm typical of the region of South Jiangsu in winter and summer. Results show that in wastewater treatment using the prevailing biogas digesters, as the incoming wastewater was high in pollutant concentration,and its hydraulic retention time was short, the treatment was only able to remove 12.9%-69.3%, 20.4%-60.9%, 25.3%-55.0%, 13.8%-18.2%, 46.8%-61.8% and 18.1%-48.7%, of the oxytetracycline (OTC), chlorotetracycline (CTC), doxycycline (DOX), sulfadiazine (SD), sulfadimidine (SM) and sulfachlorpyridazine (SCP) in the wastewater, respectively. Besides, residual concentrations of TCs and SAs in the treated wastewater were much higher in winter than in summer, especially that of CTC, SD and SCP being 0.887, 0.492 and 10.160 μg·L-1, respectively, on average. Direct discharge of such wastewater from digesters into farm fields would pose high risks to biological safety. Post-treatment of the biogas slurry through a sedimentation tank and/or a pond with hydrophyte pond, had some positive effects on removals of TCs an SAs, especially in summer, when the residual removal rate could reach up to over 90%. So it is a critical measure to dehazardize biogas slurry for its safe use in farmlands. All the findings in this study demonstrate that the technology combining anaerobic and aerobic bio-treatment processes in removing antibiotics, SAs in particular, in wastewater from animal farms is a major and effective one.

     

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