Membrane biofouling has been intensively investigated over many years; however, little attention has been paid to the role of slightly elevated nutrients in the fouling formation, especially during drinking water treatment. In this study, we evaluated the respective contribution of slightly elevated nitrogen (ca. 0.5 mg·L⁻¹) and phosphorus (ca. 0.1 mg·L⁻¹) concentrations to membrane biofouling formation and deciphered the associated mechanisms. The results demonstrated that the slight concentration elevation of nitrogen did not substantially decrease the permeate flux, but approximately 50% of the permeate flux was reduced by the elevated phosphorus. The fouling layer was thickened about 4–fold due to the slight elevation of phosphorus and this resulted in the best removal performance of fluorescent organics. In contrast, the fouling layer structure was not markedly changed by the elevated nitrogen. The concentrations of proteins and polysaccharides in the fouling layers increased to different degrees, with phosphorus playing a more pronounced role than nitrogen. The molecular experiments revealed that the filamentous Arthronema dominated the nitrogen–enriched fouling layer, but they decreased to nearly zero in the phosphorus–enriched fouling layer, and the Xanthobacter, which was capable of secreting large amounts of EPS, was enhanced. The growth of algae Chlorellales was stimulated by the elevated nitrogen, while Sphaeropleales was dominant with elevated phosphorus, and for protozoa, Vannella was increased by nitrogen, whereas members of Hartmannella were enhanced by phosphorus. Our findings indicate that the impact of slight increases in concentration of nutrients, especially phosphorus, should be taken into account in drinking water treatment.

多年来，人们对膜生物污垢进行了深入研究。然而，很少有人关注微量升高的营养物质在污垢形成中的作用，尤其是在饮用水处理过程中。在这项研究中，我们评估了略微升高的氮（约 0.5 mg·L ^-1）和磷（约 0.1 mg·L ^-1) 浓度对膜生物污染的形成并破译相关机制。结果表明，氮的轻微浓度升高并没有显着降低渗透通量，但大约 50% 的渗透通量因磷的升高而降低。由于磷的轻微升高，污垢层增厚了约 4 倍，这导致荧光有机物的去除性能最佳。相比之下，污垢层结构没有因氮的升高而显着改变。污垢层中蛋白质和多糖的浓度都有不同程度的增加，其中磷的作用比氮的作用更明显。分子实验表明，丝状关节炎富氮污染层占主导地位，但在富磷污染层中它们几乎为零，并且能够分泌大量EPS的黄杆菌得到增强。藻类小球藻的生长受氮升高的刺激，而球藻纲的生长受磷升高的影响，原生动物的生长受氮的影响，而哈特曼氏菌的成员受磷的增强。我们的研究结果表明，在饮用水处理中应考虑营养物质（尤其是磷）浓度略有增加的影响。