Drinking water treatment residue (DWTR)-based biofilter is an environment-friendly and cost-effective technology for eliminating nutrients and emerging organic contaminants (EOCs) from natural water. This study explored the removal efficiencies of five trace-level EOCs and the associated microbial response of biofilm in two identical DWTR-based biofilters under varying hydraulic loading rate (HLR) conditions over six months of operation. The results showed that the most recalcitrant EOC (carbamazepine) was mainly removed by DWTR adsorption (7.8–11.0 ng g), while the response of the biofilm community to HLR significantly affected the degradation of 17α-ethinylestradiol, sulfamethoxazole, roxithromycin, and sulfathiazole ( < 0.001). A higher HLR significantly stimulated the production of extracellular polymeric substance and increased the stochasticity and diversity of community assembly, improving denitrification and the removal efficiency of DWTR-based biofilm for biodegradable roxithromycin (80 %) and sulfamethoxazole (76 %). In contrast, lower HLR led to carbon limitation and exerted substrate selection pressures, resulting in more deterministic and stable community assembly, with keystone species such as enriched in EOC degradation-related functional genes. Moreover, co-occurrence network analysis revealed a simpler but more intensive interaction network among EOC degraders under the lower HLR condition. This interaction network facilitated the co-metabolism of influent organic carbon and the removal of more recalcitrant contaminants, 17α-ethinylestradiol (48 %) and sulfathiazole (37 %). This study offered a novel insight into biofilter management from a hybrid perspective of environmental microbiology and engineering science, highlighting the dynamic adaptation of microbes to specific EOC degradation under varying HLR conditions.

中文翻译：

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饮用水处理残留物生物过滤系统中新兴有机污染物的不同去除：水力负荷率对微生物学的影响


基于饮用水处理残渣 (DWTR) 的生物过滤器是一种环保且经济高效的技术，用于消除天然水中的营养物质和新兴有机污染物 (EOC)。本研究探讨了两个相同的基于 DWTR 的生物过滤器在不同水力负载率 (HLR) 条件下运行六个月期间五种痕量 EOC 的去除效率以及生物膜的相关微生物反应。结果表明，最顽固的 EOC（卡马西平）主要通过 DWTR 吸附去除（7.8–11.0 ng g），而生物膜群落对 HLR 的响应显着影响 17α-炔雌醇、磺胺甲恶唑、罗红霉素和磺胺噻唑的降解（ <0.001）。较高的 HLR 显着刺激细胞外聚合物的产生，增加群落组装的随机性和多样性，提高反硝化作用和基于 DWTR 的生物膜对可生物降解的罗红霉素 (80%) 和磺胺甲恶唑 (76%) 的去除效率。相比之下，较低的 HLR 导致碳限制并施加底物选择压力，从而导致更具确定性和稳定的群落组装，其中关键物种（例如富含 EOC 降解相关功能基因）的群落组装。此外，共现网络分析揭示了在较低 HLR 条件下 EOC 降解剂之间存在更简单但更密集的相互作用网络。这种相互作用网络促进了流入有机碳的共同代谢，并去除了更顽固的污染物，即 17α-炔雌醇 (48%) 和磺胺噻唑 (37%)。 这项研究从环境微生物学和工程科学的混合角度对生物过滤器管理提供了新颖的见解，强调了微生物在不同 HLR 条件下对特定 EOC 降解的动态适应。