Department of Civil, Environmental & Geomatic Engineering, University College London, London WC1E 6BT, UK.
Department of Chemistry, University College London, London WC1E 6BT, UK.
J Hazard Mater. 2023 Oct 15;460:132511. doi: 10.1016/j.jhazmat.2023.132511. Epub 2023 Sep 9.
The granular activated carbon (GAC) sandwich modification to slow sand filtration could be considered as a promising technology for improved drinking water quality. Biofilms developed on sand and GAC surfaces are expected to show a functional diversity during the biofiltration. Bench-scale GAC sandwich biofilters were set-up and run continuously with and without antibiotic exposure. Surface sand (the schmutzdecke) and GAC biofilms were sampled and subject to high-throughput qPCR for antibiotic resistance gene (ARG) analysis and 16 S rRNA amplicon sequencing. Similar diversity of ARG profile was found in both types of biofilms, suggesting that all ARG categories decreased in richness along the filter bed. In general, surface sand biofilm remained the most active layer with regards to the richness and abundance of ARGs, where GAC biofilms showed slightly lower ARG risks. Network analysis suggested that 10 taxonomic genera were implicated as possible ARG hosts, among which Nitrospira, Methyloversatilis and Methylotenera showed the highest correlation. Overall, this study was the first attempt to consider the whole structure of the GAC sandwich biofilter and results from this study could help to further understand the persistence of ARGs and their association with the microbial community in drinking water biofiltration system.
颗粒活性炭（GAC）夹层改性慢砂滤池可以被认为是一种提高饮用水水质的有前途的技术。预计在生物过滤过程中，砂和 GAC 表面上形成的生物膜将显示出功能多样性。建立了台式 GAC 夹层生物滤池，并在有和没有抗生素暴露的情况下连续运行。采集表层砂（schmutzdecke）和 GAC 生物膜样本，并进行高通量 qPCR 分析抗生素抗性基因（ARG）和 16S rRNA 扩增子测序。两种生物膜的 ARG 图谱具有相似的多样性，表明所有 ARG 类别沿滤床的丰富度都降低了。一般来说，表层砂生物膜在 ARG 的丰富度和丰度方面仍然是最活跃的层，而 GAC 生物膜的 ARG 风险略低。网络分析表明，有 10 个分类属可能与 ARG 有关，其中硝化螺旋菌、甲基厌氧甲烷杆菌和甲基贪噬菌与 ARG 的相关性最高。总的来说，本研究首次尝试考虑 GAC 夹层生物滤池的整体结构，本研究的结果有助于进一步了解 ARGs 的持久性及其与饮用水生物过滤系统中微生物群落的关系。
