Dialkyldimethyl ammonium compound (DADMAC) is widely used in daily life as a typical disinfectant and often co-exists with the heavy metal zinc in sewage environments. This study investigated the effects of co-exposure to zinc (1 mg/L) and DADMAC (0.2–5 mg/L) on the performance, bacterial community, and resistance genes (RGs) in a partial sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation (PSAD-Anammox) system in a sequencing batch moving bed biofilm reactor for 150 days. Co-exposure to zinc and low concentration (0.2 mg/L) DADMAC did not affect the nitrogen removal ability of the PASD-Anammox system, but increased the abundance and transmission risk of free RGs in water. Co-exposure to zinc and medium-to-high (2–5 mg/L) DADMAC led to fluctuations in and inhibition of nitrogen removal, which might be related to the enrichment of heterotrophic denitrifying bacteria dominated by Co-exposure to zinc and high concentration DADMAC (5 mg/L) stimulated the secretion of extracellular polymeric substances and increased the proliferation risk of intracellular RGs in sludge. This study provided insights into the application of PSAD-Anammox system and the ecological risks of wastewater containing zinc and DADMAC.

中文翻译：

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暴露于锌和二烷基二甲基铵化合物会改变部分硫自养反硝化与厌氧氨氧化过程中的细菌群落结构和抗性基因水平


二烷基二甲基铵化合物（DADMAC）作为一种典型的消毒剂广泛应用于日常生活中，并且经常与污水环境中的重金属锌共存。本研究调查了同时接触锌 (1 mg/L) 和 DADMAC (0.2–5 mg/L) 对部分硫自养反硝化与厌氧铵结合的性能、细菌群落和抗性基因 (RG) 的影响氧化 (PSAD-Anammox) 系统在序批式移动床生物膜反应器中进行 150 天。锌和低浓度 (0.2 mg/L) DADMAC 的共同暴露不会影响 PASD-Anammox 系统的脱氮能力，但会增加水中游离 RG 的丰度和传播风险。锌和中高（2-5 mg/L）DADMAC 共同暴露导致脱氮效果波动和抑制，这可能与锌和高浓度 DADMAC 共同暴露为主的异养反硝化细菌的富集有关。浓度 DADMAC (5 mg/L) 会刺激细胞外聚合物的分泌，并增加污泥中细胞内 RG 的增殖风险。本研究为PSAD-Anammox系统的应用以及含锌和DADMAC废水的生态风险提供了见解。