This study investigates the response of activated sludge to continuous nanosilver (AgNPs) input in a large concentration range. In addition to substrate removal, changes taking place in the different fractions of Extracellular Polymeric Substances (EPS), namely, very loosely bound-EPS (VLB-EPS), loosely bound-EPS (LB-EPS), and tightly bound-EPS (TB-EPS), as well as the protein and carbohydrate content of each fraction were examined. At relatively low AgNP concentrations (5 mg/L), production of loosely bound fractions became higher. At AgNP ≥ 12 mg/L, also TB-EPS production was promoted. Seemingly, bacteria were protected from inhibitory effects by regulation of EPS production. Moreover, new proteins emerged in EPS. Respiration tests indicated no effect on substrate removal even at high AgNP concentrations because the nanomaterial lost its effectiveness upon continuous aeration. In WWTPs, AgNP concentrations are normally below 0.8 mg/L. Therefore, no negative impact on substrate removal and no visible changes in EPS production would be expected.

这项研究调查了活性污泥在较大浓度范围内对连续纳米银（AgNPs）输入的响应。除去除底物外，细胞外聚合物（EPS）的不同部分也发生了变化，即非常松散结合的EPS（VLB-EPS），松散结合的EPS（LB-EPS）和紧密结合的EPS（检查了TB-EPS）以及每个部分的蛋白质和碳水化合物含量。在相对较低的AgNP浓度（5 mg / L）下，松散结合的馏分的产量更高。当AgNP≥12 mg / L时，也促进了TB-EPS的产生。看来，通过调节EPS的产量可以保护细菌免受抑制作用。此外，EPS中出现了新的蛋白质。呼吸测试表明，即使在高AgNP浓度下，对底物的去除也没有影响，因为纳米材料在连续通气后失去了有效性。在污水处理厂中，AgNP浓度通常低于0.8 mg / L。因此，不会对基材去除产生负面影响，也不会预期EPS产生明显变化。