College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China.
Water Res. 2020 Jul 1;178:115851. doi: 10.1016/j.watres.2020.115851. Epub 2020 Apr 23.
Triclocarban (TCC) is a highly effective antibacterial agent, which is widely used in a variety of applications and present at significant levels (e.g., 760 μg/L) in wastewater worldwide. However, the interaction between TCC and nitrifiers, important microbial cultures in wastewater treatment plants, has not been documented. This work therefore aimed to evaluate the fate of TCC in a nitrifying culture and its impact on nitrifiers in four long-term nitrifiers-rich reactors, which received synthetic wastewater containing 0, 0.1, 1, or 5 mg/L TCC. Experimental results showed that 36.7%-50.7% of wastewater TCC was removed by nitrifying cultures in stable operation. Mass balance analysis revealed that the removal of TCC was mainly achieved through adsorption rather than biodegradation. Adsorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for the removal while fourier transform infrared spectroscopy indicated that several functional groups such as hydroxyl, amide and polysaccharide seemed to be the main adsorption sites. The adsorbed TCC significantly deteriorated settleability and performance of nitrifying cultures. With an increase of influent TCC from 0 to 5 mg/L, reactor volatile suspended solids and effluent nitrate decreased from 1200 ± 90 mg/L and 300.81 ± 7.52 mg/L to 880 ± 80 and 7.35 ± 4.62 mg/L while effluent ammonium and nitrite increased from 0.41 ± 0.03 and 0.45 ± 0.23 mg/L to104.65 ± 3.46 and 182.06 ± 7.54 mg/L, respectively. TCC increased the extracellular polymeric substances of nitrifying cultures, inhibited the specific activities of nitrifiers, and altered the abundance of nitrifiers especially Nitrospira sp.. In particular, TCC at environmentally relevant concentration (i.e., 0.1 mg/L) significantly inhibited NOB activity and reduced NOB population.
三氯生（TCC）是一种高效的抗菌剂，广泛应用于各种领域，其在全球废水中的浓度很高（例如 760μg/L）。然而，TCC 与硝化菌（废水处理厂中重要的微生物种群）之间的相互作用尚未被记录。因此，本工作旨在评估 TCC 在硝化培养物中的归宿及其对四个长期富含硝化菌的反应器中硝化菌的影响，这些反应器接收含有 0、0.1、1 或 5mg/L TCC 的合成废水。实验结果表明，稳定运行的硝化培养物可去除废水中 36.7%-50.7%的 TCC。质量平衡分析表明，TCC 的去除主要通过吸附而不是生物降解。吸附动力学分析表明，非均相多层吸附是去除 TCC 的主要机制，傅里叶变换红外光谱表明，羟基、酰胺和多糖等几种功能基团似乎是主要的吸附位点。被吸附的 TCC 显著恶化了硝化培养物的沉降性能和处理效果。当进水 TCC 从 0 增加到 5mg/L 时，反应器的挥发性悬浮固体和出水硝酸盐分别从 1200±90mg/L 和 300.81±7.52mg/L 降至 880±80mg/L 和 7.35±4.62mg/L，而出水氨氮和亚硝酸盐分别从 0.41±0.03mg/L 和 0.45±0.23mg/L 增加到 104.65±3.46mg/L 和 182.06±7.54mg/L。TCC 增加了硝化培养物的胞外聚合物，抑制了硝化菌的比活性，并改变了硝化菌的丰度，尤其是硝化螺旋菌属。特别是，环境相关浓度（即 0.1mg/L）的 TCC 显著抑制了亚硝酸盐氧化菌（NOB）的活性并降低了其种群数量。
