抗性基因在抗生素制药废水处理过程的分布特征、消长机制及控制原理

Antibiotic resistance genes (ARGs) as the emerging pollutant, have been paid more concern in the recent years. Pharmaceutical wastewater treatment process is the highly polluted area of the ARGs because of the high residues of the antibiotics during its treatment process. This project will apply the qPCR and high-throughput DNA sequencing techniques to study the antibiotic resistance genes in the pharmaceutial waste water treatment process. The field work combined with the laboratory scale simulation was applied. To evaluate the treating efficiency of the ARGs in pharmaceutical waste water treatment process, a reliable method including DNA extraction and qPCR quantify was established. The spacial distribution and fate of ARGs during different processing unit was studied to promulgate the pollution profile and trend of ARGs. The high-throughput DNA sequencing technique was applied to study the mechanism of growth and decline of ARGs and possible influencing factors in the key unit. The molecular mechanism of ARGs propagation in the pharmaceutial waste water process was elucidated. Finally, the laboratory scale study was applied to study the treating efficiency of different forms of ARGs and key influencing factors. The principle of ARGs control in pharmaceutial waste water was clarified. This study provides baseline data to establish the discharge standard for the antibiotics and ARGs and provides theoretical reference for ARGs deep reduce in pharmaceutial wastewater.

针对抗生素制药废水处理过程很可能成为抗性基因污染的高发区域，本项目拟采用分子生物学手段qPCR和最新宏基因组高通量测序技术，现场采样和室内小试模拟相结合，围绕抗生素制药废水中的抗性基因污染开展工作。研究建立一套通用可靠的方法技术体系评估典型抗生素制药废水现行处理工艺对抗性基因的处理效率。研究抗性基因在不同废水处理单元的空间分布及归趋，揭示制药废水处理过程抗性基因的污染特征及消长规律。采用宏基因组手段重点研究关键单元抗性基因的消长机制及影响因素，阐明抗性基因在制药废水处理过程中传播扩散的分子机制。室内小试模拟研究抗生素制药废水深度处理对不同形态抗性基因的处理效率及关键调控因子识别，阐明抗性基因在抗生素制药废水处理过程中的控制原理。该研究为科学制定制药废水抗生素及抗性基因的排放标准提供理论依据，为抗生素制药废水针对抗性基因的深度削减提供理论参考。

该研究针对抗生素制药废水处理过程很可能成为抗性基因污染的高发区域，采用分子生物学手段qPCR和最新宏基因组高通量测序技术，现场采样实验室分析结合污水处理室内小试模拟。结果发现，典型抗生素制药废水现行处理工艺对抗生素的处理效率在48-99%之间，发生在生物单元的降解是抗生素去除的主要机制。与进水相比，尽管抗性基因的出水含量有所降低（0.5-2.5个数量级），但并没有被真正去除，抗性基因通过污泥沉降被转移至脱水污泥中，浓度高达(9.380.73)107至(4.300.81)1010 copies/g dw，增加其进入环境的风险。研究发现，制药废水高浓度的抗生素对出水中的抗性基因够成了环境选择压力，因此减少抗生素进入制药废水处理系统可以有效地减少抗性基因的增殖。脱水污泥与出水排放的抗性基因的总量比进水中高，个别基因亚型高达14倍，表明经污水处理后抗性基因非但没有降低，反而发生了增殖，增殖主要发生在生物单元。对比不同生物处理工艺，传统的活性污泥法比周期循环活性污泥法（CASS）、序批式活性污泥法（SBR）和膜生物反应器方式（MBR）对抗性基因的增殖效果更为显著。制药废水中进水COD负荷和抗生素浓度在生物处理单元中对四环素类抗生素去除效率影响较大，进水COD负荷的增加促进TCs去除率的增加，相反，抗生素浓度的升高则导致了TCs去除效率降低。通过废水关键生化处理单元抗性基因削减模型的建立及优化控制研究获得了不同处理单元包括深度处理工艺对典型抗性基因的去除，结果发现化学氧化处理对抗性基因去除效果明显，相比紫外UV（去除率-0.3-1.4个数量级）和臭氧O3（去除率-1.0-1.0个数量级），Fenton工艺对抗性基因具有最高的处理效率（去除率高达2个数量级）。尤其是Fenton及UV+Fenton联合工艺效果最好，去除率最高能达到2个数量级。该研究为我国制药废水抗性基因的排放种类及浓度提供第一手数据，为科学制定制药废水抗生素及抗性基因的排放标准提供理论依据，为抗生素制药废水针对抗性基因的深度削减提供理论参考。