Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, School of Environmental and Natural Resources, Zhejiang University of Science and Technology, Hangzhou 310023, China.
Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Waste Manag. 2022 Jan 1;137:89-99. doi: 10.1016/j.wasman.2021.10.029. Epub 2021 Nov 5.
Conditioning can drastically improve the dewaterability of sewage sludge and is widely practiced in most wastewater treatment plants (WWTPs). Sludge conditioning was also reported as a crucial step in sludge treatment to attenuate antibiotic resistance, but it remains unclear whether the attenuated antibiotic resistance by conditioning treatments would guarantee low abundance of antibiotic resistance genes (ARGs) in the compost products of municipal sewage sludge. Herein, the impacts of three conditioning treatments, including bioleaching and chemical conditioning using Fe[III]/CaO or polyacrylamide (PAM), on the abundances of 20 ARGs and 4 mobile genetic elements (MGEs) during conventional aerobic composting of dewatered sludge were investigated. It was found that the absolute and relative abundances of total ARGs in compost product of bioleached sludge accounted for only 13.8%-28.8% of that in compost products of un-conditioned, Fe[III]/CaO-conditioned, or PAM-conditioned sludges. Besides, bioleaching conditioning resulted in the lowest abundances of ARG subtypes and ARG-associated bacteria in the sludge compost product. The shift of ARG profiles in the bioleached sludge composting can be mainly ascribed to the ARG-associated bacteria, while the MGEs drove the ARG profiles during conventional composting of un-conditioned sludge and the two chemically conditioned sludge. Thus, bioleaching conditioning is superior to the chemical conditioning using Fe[III]/CaO or PAM in mitigating antibiotic resistance in sludge compost products, which was contributed by the pre-removal of ARGs prior to composting treatment and the potential limitation of ARGs transfer during conventional composting.
调理可以显著改善污水污泥的脱水性能，并且在大多数废水处理厂（WWTP）中广泛应用。污泥调理也被报道为污泥处理的关键步骤，以减弱抗生素抗性，但调理处理减弱的抗生素抗性是否能保证城市污水污泥堆肥产品中抗生素抗性基因（ARGs）的低丰度仍不清楚。在此，研究了三种调理处理（包括生物沥滤和使用 Fe[III]/CaO 或聚丙烯酰胺（PAM）的化学调理）对脱水污泥常规好氧堆肥过程中 20 个 ARGs 和 4 个移动遗传元件（MGEs）丰度的影响。结果发现，生物沥滤污泥堆肥产物中总 ARGs 的绝对丰度和相对丰度仅占未调理、Fe[III]/CaO 调理或 PAM 调理污泥堆肥产物中总 ARGs 的 13.8%-28.8%。此外，生物沥滤调理导致污泥堆肥产物中 ARG 亚类和 ARG 相关细菌的丰度最低。生物沥滤污泥堆肥中 ARG 图谱的变化主要归因于 ARG 相关细菌，而 MGEs 在未调理污泥和两种化学调理污泥的常规堆肥过程中驱动了 ARG 图谱。因此，与使用 Fe[III]/CaO 或 PAM 的化学调理相比，生物沥滤调理在减轻污泥堆肥产品中的抗生素抗性方面更具优势，这归因于在堆肥处理前预先去除 ARGs 以及在常规堆肥过程中 ARGs 转移的潜在限制。
