Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China; Hunan BISEN Environmental & Energy Co. Ltd., Changsha 410100, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
School of Environment, Tsinghua University, Beijing 100084, China.
Sci Total Environ. 2022 Feb 25;809:152221. doi: 10.1016/j.scitotenv.2021.152221. Epub 2021 Dec 8.
Biophysical drying (BPD) is one of the best alternatives for reducing the moisture content from sewage sludge by utilizing biological heat from aerobic reactions. However, the fate of emerging pollutants during BPD process is largely unknown. In this study, the fates of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) were investigated during a pilot-scale BPD treatment of sewage sludge. A total of 20 types (388 subtypes) of ARGs and 16 types (364 subtypes) of MRGs were detected by metagenomic sequencing and annotation. The total abundance of ARGs decreased from 1.78 ± 0.13 copies/16S rRNA to 0.55 ± 0.01 copies/16S rRNA while the total abundance of MRGs increased from 3.81 ± 0.01 copies/16S rRNA to 6.30 ± 0.02 copies/16S rRNA, showing the distinct behaviors of ARGs and MRGs during BPD process. The ARGs were effectively reduced during the mesophilic and thermophilic stages of BPD process and the reduction of ARGs fitted the first-order kinetic model (p < 0.01). Microbial community analysis showed that the abundance of potential pathogens also decreased during BPD process. On the contrary, the abundances of most MRG subtypes (78.3%) were enriched during BPD process with up to 122-fold change, implying the potential threats for the end product of BPD process. These results together indicate that although the ARGs and potential pathogens can be effectively reduced during BPD process, the safety for the end product still needs to be considered due to the enrichment of MRGs.
生物物理干燥（BPD）是利用好氧反应产生的生物热来降低污水污泥水分含量的最佳方法之一。然而，在 BPD 过程中新兴污染物的命运在很大程度上是未知的。在这项研究中，通过宏基因组测序和注释，研究了抗生素抗性基因（ARGs）和金属抗性基因（MRGs）在污水污泥中进行的中试规模 BPD 处理过程中的命运。共检测到 20 种（388 种亚型）ARGs 和 16 种（364 种亚型）MRGs。ARGs 的总丰度从 1.78±0.13 拷贝/16S rRNA 降低到 0.55±0.01 拷贝/16S rRNA，而 MRGs 的总丰度从 3.81±0.01 拷贝/16S rRNA 增加到 6.30±0.02 拷贝/16S rRNA，表明 ARGs 和 MRGs 在 BPD 过程中表现出不同的行为。ARGs 在 BPD 过程的中温和高温阶段得到有效去除，ARGs 的减少符合一级动力学模型（p<0.01）。微生物群落分析表明，潜在病原体的丰度也在 BPD 过程中降低。相反，大多数 MRG 亚型（78.3%）在 BPD 过程中得到了富集，最高可达 122 倍的变化，这意味着 BPD 过程的最终产物存在潜在威胁。这些结果表明，尽管 ARGs 和潜在病原体可以在 BPD 过程中得到有效去除，但由于 MRGs 的富集，仍需要考虑 BPD 过程最终产物的安全性。
