抗生素废水处理过程中耐药菌与抗性基因的转归特征与去除机制研究

China is the largest producer of antibiotics in the world, with the largest quantity of discharged antibiotic wastewater. Antibiotic wastewater is full of antibiotic resistance bacteria (ARB) and genes (ARG), which make antibiotic wastewater the important pollutant source of resistance dissemination. However, there is a missing gap of removing ARB and ARG in the antibiotic wastewater at present around the world. Therefore, the purposes of this study aim to improve the removal performance of ARB and ARG in antibiotic wastewater treatment and understand the mechanism of removing ARB and ARG. As the most used antibiotics of human and veterinary, wastewater of ??-lactam or tetracycline antibiotics is selected in this project, and the fate, distribution and removals of ARB and ARG during antibiotic wastewater/sludge treatment processes will be investigated by field survey and lab experiments. As for improving removal performance of ARB and ARG in wastewater and sludge, memberane bioreactor (MBR) and sludge pretreatment-anaerobic digestion processes will be optimised instead of the conventional processes of antibiotic wastewater treatment.Meanwhile, the mechanism of removing ARB and ARG in antibiotic wastewater and sludge treatment processes will be analyzed through investigating links among residual antibiotics, microbial community and ARB & ARG. Results of this project would be beneficial for antibiotic resistance dissemination control in China.

我国是抗生素最大生产与消费国，废水排放量大。抗生素废水及其处理过程产生的污泥中含有大量耐药菌（Antibiotic resistance bacteria,ARB）与抗性基因(Antibiotic resistance genes,ARG)，是抗性传播的重要污染源。但目前国内外缺乏抗生素废水处理过程中ARB与ARG去除的深入研究。因此，本课题以使用最广泛的抗生素β-内酰胺类/四环素类抗生素废水为研究对象，通过现场调查和实验室研究，考察ARB与ARG在抗生素废水、污泥处理过程中的转归特征与去除效果；以提高ARB和ARG去除效果为目的，重点考察膜生物反应器和污泥预处理+厌氧消化工艺对抗生素废水与污泥中ARB与ARG去除效果的影响，优化工艺操作参数；研究处理过程中ARB及ARG与抗生素残留量和微生物群落特征的相互联系，探讨ARB与ARG的去除机制，为我国有效控制抗性传播提供科学依据。

抗生素废水及其剩余污泥中含有大量耐药菌（Antibiotic resistance bacteria, ARB）与抗性基因(Antibiotic resistance genes, ARGs)，是抗性传播的重要污染源。因此本课题对抗生素废水及其剩余污泥处理过程中ARB与ARGs归趋进行深入研究，以期为控制抗性污染传播提供科学依据。研究结果表明：.（1）螺旋霉素废水处理厂厌氧-缺氧-好氧工艺能有效削减肠球菌；各单元分离出的肠球菌对4种大环内酯类抗生素均为100%耐药；原厂工艺对肠球菌的耐药率并无削减作用，肠球菌ermB检出率在污水处理过程中仅削减9%。废水生物处理对污水中的ermB、ermF、mefA、ereA、mphB和Tn916/1545浓度有削减效果，但会导致ermX、intI1、ISCR1浓度增加。.（2）与现场好氧工艺对比，好氧MBR工艺对肠球菌耐药率、ermB检出率，以及污水中的ARGs和转移元件都有更佳的削减效果，在出水水质指标近似时，HRT越长对肠球菌耐药性和ARGs的处理效果越好。.（3）原厂剩余污泥中含有大量的耐药肠球菌和ARGs，采用微波、热水解、臭氧污泥预处理强化厌氧消化。微波和热水解预处理可显著去除肠球菌，但不能削减肠球菌耐药性，其携带ARGs的检出率不减甚至有所增加，但可有效削减污泥中的ARGs和移动元件，削减效果为热水解>微波>臭氧。.（4）污泥中温厌氧消化可导致ARGs和移动元件总浓度增加，肠球菌对四环素的耐药率增加。厌氧消化后，与未预处理污泥相比，微波和热水解污泥ARGs和移动元件总浓度和丰度最低。.（5）污水和污泥中ARGs受多种因素影响：①转移元件的影响：无论在污水还是污泥中，ermB， mphB，ermX之间的相关性较强，且都受intI1影响较大。②环境因素的影响：污水中COD对Tn916/1545有正向影响，而mefA受氨氮影响显著；ereA，ermB，ermF，mphB与生物量和COD的正相关。污泥中ermB，ermF，ermX，intI1与螺旋霉素和新螺旋霉素残余浓度均密切相关。mphB与螺旋霉素和污泥有机组分相关，mefA受碱度影响较大。③群落结构的影响：浮霉菌门、酸杆菌门、绿弯菌门和变形菌门对intI1、ermF、ermX正相关，ISCR1与TM7菌门有关，厚壁菌门则对mefA和Tn916/1545有正向影响。