Lime addition significantly attenuates tetracycline resistance genes and class 1 integrons in dewatered sludge by affecting bacterial profiles. Issue 3 (June 2022)

• Record Type: Journal Article
• Authors: Chen, Maoxia; Chang, Jiali; Jiang, Tao; Wei, Shiqian; Zou, Jiawei; Yang, Juan; Ma, Xuguang
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 3(2022)
• Publication Date: 2022-06
• Subjects: ARGs antibiotic resistance genes -- EFF efflux pump -- EAS excess activated sludge -- MGEs mobile genetic elements -- RPP ribosome protection protein -- WWTPs wastewater treatment plants -- AD anaerobic digestion -- CASS cyclic activated sludge system; Tetracycline resistance genes -- Excess activated sludge -- Lime addition treatment -- Moisture content -- Microbial community variation; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.107429
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: To verify the hypothesis that adding lime can remove antibiotic resistance genes (ARGs) in excess activated sludge (EAS), in this study, we explored the effects of lime addition at different ratios on the removal of tetracycline resistance genes (TRGs, tetW / tetS / tetZ / tetC / tetX ) and class 1 integrons ( intI1 ) in dewatered EAS. The microbial community succession was also analyzed. Drying without lime addition for 7 d significantly reduced the total content of TRGs and intI1 with a removal efficiency of 72.88%, and lime addition further promoted the removal effect and achieved a removal efficiency exceeding 98.54%. A higher L/S ratio did not result in more effective removal of TRGs. The fate of TRGs did not correlate with their resistance mechanism. Lime addition promoted the removal of TRGs by enhancing the decrease in moisture content and changing the microbial community structure. Principal component analysis suggested that the core microbial community was significantly distinct and clustered more by the treatment stage than the method used. Spearman correlation and network analyses indicated that 17 genera belonging to five phyla ( Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Nitrospirae ) were significantly positively or negatively correlated (|R| > 0.6, p < 0.05) with TRGs and intI1 . These findings increase our understanding of the benefits of lime addition treatment for attenuating TRGs and intI1 in EAS. Adding lime to EAS is straightforward and cost-effective and contributes toward preventing the release of TRGs and intI1 into the total environment. Graphical Abstract: ga1 Highlights: Total TRG content significantly reduced by 98.54% with lime addition for 7 days. A higher L/S ratio did not result in the more effective removal of TRGs. The change of TRGs did not correlate with their bacterial resistance mechanism. Lime addition promoted TRG removal by affecting microbial community structure.