摘要
抽象图像
污水污泥是抗生素抗性基因（ARGs）的主要环境库之一，而其循环利用会向农业土壤中释放大量的ARGs。污泥调理处理作为改善污泥脱水的一个不可或缺的步骤，可以提高污泥的脱水能力，同时减少污泥堆肥中的ARG，但目前尚不清楚污泥调理处理如何影响经污泥堆肥改良的不同农业土壤中的ARGs分布。在本研究中，对两种农业土壤（即红土和黄棕壤）中18种ARGs和2种可移动遗传元素（MGE）的命运进行了170天的研究，研究了不同条件处理（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）产生的污泥堆肥的土地施用。结果表明，在用生物漂白污泥堆肥改良的红土和黄棕壤中（第170天），总ARGs和MGE的绝对丰度最低，仅为用生污泥、PAM条件污泥或Fe[III]/CaO条件污泥的堆肥产物改良的相应土壤中的26.4–76.8%。此外，与其他条件处理相比，生物浸出条件处理在很大程度上限制了典型污泥载ARGs（sul2、aadA1、aadA2-01、aadA2-02和aadA2-03）及其潜在宿主的富集。研究发现，通过生物浸出处理获得的污泥携带的ARGs富集程度要低得多，这很可能是由于生物浸出污泥堆肥中ARGs的丰度较低，以及携带ARGs细菌在改良农业土壤中的生长有限。因此，在用污泥堆肥改良的不同农业土壤中，生物浸出处理在减轻抗生素耐药性方面优于使用Fe[III]/CaO或PAM的化学处理，这是由于污泥堆肥中ARGs的预先去除和污泥堆肥土地施用后携带ARGs细菌的潜在有限生长。
Abstract
Abstract Image
Sewage sludge is one of the major environmental reservoirs of antibiotic resistance genes (ARGs), while its recycling releases abundant ARGs into the agricultural soils. Sludge conditioning treatment, as an indispensable step to improve sludge dewatering, can enhance the dewaterability of sewage sludge and meanwhile attenuate ARGs in sludge compost, but it remains unclear how sludge conditioning treatments impact the ARG profiles in different agricultural soils amended with sludge composts. In the present study, the fates of 18 ARGs and 2 mobile genetic elements (MGEs) in two types of agricultural soils (i.e., red soil and yellow–brown soil) were investigated for 170 days, after the land application of sludge composts derived from different conditioning treatments, including bioleaching and chemical conditioning using Fe[III]/CaO or polyacrylamide (PAM). The results showed that the absolute abundance of total ARGs and MGEs was the lowest in both the red soil and the yellow–brown soil amended with bioleached sludge compost (Day 170), which were only 26.4–76.8% of that in the corresponding soils amended with the compost products of raw, PAM-conditioned, or Fe[III]/CaO-conditioned sludge. Besides, in comparison with other conditioning treatments, the bioleaching conditioning treatment more greatly limited the enrichment of typical sludge-borne ARGs (sul2, aadA1, aadA2-01, aadA2-02, and aadA2-03) and their potential hosts. It was found that the much less enrichment of sludge-borne ARGs achieved by bioleaching conditioning most probably resulted from both the low abundance of ARGs in bioleached sludge compost and the limited growth of bacteria carrying ARGs in the amended agricultural soils. Therefore, bioleaching conditioning is superior to the chemical conditioning using Fe[III]/CaO or PAM in mitigating antibiotic resistance in different agricultural soils amended with sludge composts, which was contributed by the preremoval of ARGs in sludge compost and the potentially limited growth of bacteria carrying ARGs after the land application of sludge compost.

https://pubs.acs.org/doi/abs/10.1021/acsestengg.2c00113