摘要
      生物物理干燥（BPD）是利用好氧反应产生的生物热降低污泥含水量的最佳替代方案之一。然而，在BPD过程中新出现的污染物的命运在很大程度上是未知的。在本研究中，研究了抗生素抗性基因（ARGs）和金属抗性基因（MRGs）在污泥BPD处理中的命运。通过宏基因组测序和注释，共检测到20种类型（388种亚型）的ARGs和16种类型（364种亚类型）的MRG。ARGs的总丰度从1.78±0.13拷贝/16S rRNA下降到0.55±0.01拷贝/16S r RNA，而MRG的总丰度则从3.81±0.01拷贝/16 S rRNA上升到6.30±0.02拷贝/16S R RNA，显示出ARGs和MRG在BPD过程中的不同行为。在BPD过程的中温和高温阶段，ARGs被有效地减少，并且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，在BPD期间，潜在病原体的丰度也降低了。相反，大多数MRG亚型（78.3%）的丰度在BPD过程中富集，变化高达122倍，这意味着对BPD过程的最终产物的潜在威胁。这些结果共同表明，尽管在BPD过程中可以有效减少ARG和潜在病原体，但由于MRG的富集，最终产品的安全性仍需考虑。
Abstract
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.

https://www.sciencedirect.com/science/article/abs/pii/S0048969721072971