Elucidating the migration characterization of antibiotic resistance genes in waste activated sludge from four distinct industrial wastewaters

The harmless treatment of industrial wastewater WAS (waste activated sludge) is a critical issue related to public health, in which understanding the occurrence and transfer characteristics of ARGs (antibiotic resistance genes) is urgent. Given the significant variations across different industries, ARGs transfer risks tend to differ substantially. To comparatively analyze the above issues and then proposed targeted management strategies, this study therefore selected WAS from four representative industrial sectors: pesticide factory (PF), traditional Chinese medicine factory (TCMF), canned meat processing factory (CMPF), and chemical industrial factory (CF). Results demonstrated these four WAS types could be classified into two groups for tailored management: PF and CF, TCMF and CMPF. All four WAS contained various organic compounds, with PF and CF may showing relatively higher toxicity, which inhibited microbial growth and reduced relative abundance of ARGs carriage. However, MGE (mobile genetic elements) were enriched, thereby promoting horizontal transfer of ARGs. Conversely, TCMF and CMPF provided conditions for microbial proliferation, generating more virulence factors and carrying higher ARGs relative loads. Vertical transfer maybe the dominate ARGs transfer pathway in these WAS, followed by conjugation. Above results demonstrated that subsequent WAS treatment should adopt category-specific, integrated technological approaches: PF and CF required thorough organic degradation coupled with MGE suppression in PF and plasmid inactivation in CF, while TCMF and CMPF necessitated complete microbial inactivation and CMPF needed augment the inhibition of biofilm formation. This tailored strategy provided an insight into ARGs control for advancing industrial WAS harmless treatment.