Nanoplastics in the environment and their effect on the ecosystem has aroused wide concern. This study investigated the effect of polystyrene nanoplastics on activated sludge properties, including nutrient removal, dewaterability, and short chain fatty acid (SCFA) production potential. The results indicated that the nanoplastics inhibited the ammonia oxidation rate and nitrate generation rate during nitrification. The denitrification rate was also inhibited in the presence of nanoplastics, while the percentage of total inorganic nitrogen removed was not affected. The phosphorus absorption rates during the aerobic stage were 75.52%, 76.19%, 60.69%, 71.58%, and 49.48% for nanoplastics concentrations of 0, 10, 50, 100, and 1,000 μg/L. The phosphorus release was inhibited in the reactors where nanoplastics were added during denitrification. These results indicate that bacteria, including nitrifiers, denitrifiers, and phosphorus-accumulating bacteria are affected by the nanoplastics. This probably attributed to the nanosize of the polystyrene effect on bacterial cells or overproduction of reactive oxygen species that caused dysfunction of microbial metabolism. SCFA production was inhibited by adding nanoplastics, particularly at a concentration of 10 μg/L, suggesting that the hydrolysis and acidification processes were affected by the nanosized polystyrene. The dewaterability of the activated sludge was improved after adding nanoplastics, this probably attributed to the aggregation of polystyrene and its function as a sludge skeleton builder. The results of this study reveal that nanoplastics have a negative effect on activated sludge properties, which should be considered for practical applications.

环境中的纳米塑料及其对生态系统的影响引起了广泛关注。这项研究调查了聚苯乙烯纳米塑料对活性污泥特性的影响，包括去除营养，脱水性和短链脂肪酸（SCFA）的生产潜力。结果表明，纳米塑料在硝化过程中抑制了氨氧化速率和硝酸盐生成速率。在存在纳米塑料的情况下，反硝化速率也受到抑制，而去除的总无机氮的百分比不受影响。对于浓度为0、10、50、100和1,000μg/ L的纳米塑料，好氧阶段的磷吸收率为75.52％，76.19％，60.69％，71.58％和49.48％。在反硝化过程中加入纳米塑料的反应器中，磷的释放受到抑制。这些结果表明，包括硝化剂，反硝化剂和磷积累细菌在内的细菌都受到纳米塑料的影响。这可能归因于聚苯乙烯对细菌细胞的纳米作用或导致微生物代谢功能障碍的活性氧的过量生产。通过添加纳米塑料（尤其是浓度为10μg/ L）可以抑制SCFA的产生，这表明水解和酸化过程受到纳米级聚苯乙烯的影响。添加纳米塑料后，活性污泥的脱水性得到了改善，这可能归因于聚苯乙烯的聚集及其作为污泥骨架助洗剂的功能。这项研究的结果表明，纳米塑料对活性污泥特性有负面影响，