摘要
      调理可以显著提高污水污泥的脱水能力，并在大多数污水处理厂（WWTP）中广泛应用。据报道，污泥调理也是污泥处理中减弱抗生素耐药性的关键步骤，但目前尚不清楚通过调理处理减弱的抗生素耐药性是否能保证城市污水污泥堆肥产品中抗生素耐药性基因（ARGs）的低丰度。本文研究了在脱水污泥的常规好氧堆肥过程中，三种条件处理，包括生物浸出和使用Fe[III]/CaO或聚丙烯酰胺（PAM）的化学条件处理，对20种ARGs和4种可移动遗传元素（MGE）丰度的影响。研究发现，生物漂白污泥堆肥产品中总ARGs的绝对和相对丰度仅占未处理、Fe[III]/CaO处理或PAM处理污泥堆肥产品的13.8%-28.8%。此外，生物浸出条件导致污泥堆肥产品中ARG亚型和ARG相关细菌的丰度最低。生物漂白污泥堆肥中ARG谱的变化主要归因于ARG相关细菌，而在未经处理的污泥和两种化学处理的污泥的常规堆肥过程中，MGE驱动了ARG谱。因此，在减轻污泥堆肥产品中的抗生素耐药性方面，生物浸出处理优于使用Fe[III]/CaO或PAM的化学处理，这是由于在堆肥处理之前预先去除了ARGs，以及传统堆肥过程中ARGs转移的潜在限制。
Abstract
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.

https://www.sciencedirect.com/science/article/abs/pii/S0956053X21005699